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SEAS Standing Faculty Research Directory
Alphabetical

Faculty Listed Alphabetically
Faculty Listed by Department

A   B   C   D   E   F   G   H   I   J   K   L   M  
N   O   P   Q   R   S   T   U   V   W   X   Y   Z  



Ritesh Agarwal

Assistant Professor of Materials Science and Engineering
Email: riteshag at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
I am primarily interested in the studies of the properties of self-assembled nanostructured materials ranging from molecular to macroscopic length scales with a goal of developing the bottom-up paradigm to assemble virtually any kind of a functional system ranging from integrated photonics and electronics to chemical or biological sensors. The underlying theme of my research interests centers on rational synthesis of nanomaterials with accurate control over dimension and composition, detailed understanding of the modified properties of materials at the nanoscale, development of novel device technologies based on the unique properties of nanomaterials, and the integration of nanostructures on a common platform during the assembly process with exquisite spatial control.

Specfic Research Areas include:
1) Growth and characterization of complex but precisely defined nanowire heterostructures for the assembly of novel nanophotonic devices based on quantum confinement effects.

2) Evolve schemes for the assembly of nanostructured materials into complex, yet well controlled patterns by combining the holographic optical tweezer (HOT) technique with other chemical, physical or biological based assembly approaches.

Selected Recent Publications:
R. Agarwal, K. Ladavac, Y. Roichman, G. Yu, C. M. Lieber and D. G. Grier, "Manipulation and Assembly of Nanowires with Holographic Optical Traps," Submitted.

O. Hayden, R. Agarwal, and C.M. Lieber, "Nanowire Based Avalanche Photodiodes, " Submitted.

R. Agarwal, C.J. Barrelet and C.M. Lieber, "Lasing in Single Cadmium Sulfide Nanowire Optical Cavities," Nano Lett. 5, 917 (2005).

X. Duan, Y. Huang, R. Agarwal and C. M. Lieber, "Single-Nanowire Electrically Driven Lasers," Nature 421, 241-245 (2003).


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Rajeev Alur

Zisman Family Professor of Computer and Information Science
Email: alur at cis.upenn.edu
Personal Website

Research Interests:
Design tools for embedded software, Formal modeling and verification of reactive systems, Model checking, Hybrid systems, Distributed computing, Logic and automata theory.

Selected Recent Publications:
Analysis of recursive state machines. Alur, R; Benedikt, M; Etessami, K; Godefroid, P; Reps, T; Yannakakis, MACM TRANSACTIONS ON PROGRAMMING LANGUAGES AND SYSTEMS, 27 (4): 786-818 JUL 2005.

R. Alur, K. Etessami, and M. Yannakakis. Realizability and verification of MSC graphs. Theoretical Computer Science, 2005.

R. Alur, K. McMillan, and D. Peled. Deciding global partial-order properties. Formal Methods in Design, 2005.

R. Alur, P. Madhusudan, and W. Nam. Symbolic compositional verification by learning assumptions. 17th International Conference on Computer-Aided Verification, 2005.

R. Alur, V. Kumar, P. Madhusudan, and M. Viswanathan. Congruences for visibly pushdown languages. 32nd International Colloquium on Automata, Languages, and Programming, 2005.

R. Alur, S. Chaudhuri, K. Etessami, and P. Madhusudan. On-the-fly reachability and cycle detection for recursive state machines. 11th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, 2005.

R. Alur, S. La Torre and P. Madhusudan. Perturbed timed automata, Eighth International Workshop on Hybrid Systems: Computation and Control, 2005.

R. Alur and A. Chandrashekharapuram. Dispatch sequences for embedded control models. 11th IEEE Real-Time and Embedded Technology and Applications Symposium, 2005.

S. Burckhardt, R. Alur, and M. Martin. Verifying safety of a token coherence implementation by parametric compositional refinement. Sixth International Conference on Verification, Model Checking, and Abstract Interpretation, 2005.

R. Alur, P. Cerny, P. Madhusudan, and W. Nam. Synthesis of interface specifications for Java classes. 32nd ACM Symposium on Principles of Programming Languages, 2005.

R. Alur, S. Kannan, and S. La Torre. Polyhedral flows in hybrid automata. Formal Methods in System Design, 2004.

Z. Yang and R. Alur. Variable reuse for efficient image computation. 5th International Conference on Formal Methods in Computer-Aided Design, 2004.

Alur, R. Games for formal design and verification of reactive systems. Automated Technology for Verification and Analysis. Second International Conference, ATVA 2004. Proceedings (Lecture Notes in Computer Science Vol. 3299, 2004, p 1.

M. McDougall, R. Alur, and C.A. Gunter. A model-based approach to integrating security policies for embedded devices. Fifth ACM Conference on Embedded Software, 2004.

R. Alur and P. Madhusudan. Decision problems for timed automata: A survey. 4th Intl. School on Formal Mthods for Computer, Communication, and Software Systems: Real Time, 2004.

R. Alur, M. Bernadsky, and P. Madhusudan. Optimal reachability for weighted timed games. 31st International Colloquium on Automata, Languages, and Programming, 2004.

R. Alur, K. Etessami, and P. Madhusudan. A temporal logic of nested calls and returns. Tenth International Conference on Tools and Algorithms for the Construction and Analysis of Systems, 2004.

R. Alur and P. Madhusudan. Visibly pushdown languages. 36th ACM Symposium on Theory of Computing, 2004.

M. Bernadsky, R Sharykin, and R. Alur. Structured modeling of concurrent stochastic hybrid systems. Joint Conference on Formal Modeling and Analysis of Timed Systems and Formal Techniques in Real-Time and Fault Tolerant Systems, 2004.

R. Alur and R. Grosu. Modular refinement of hierarchic reactive machines. ACM Transactions on Programming Languages and Systems, 2004

R. Alur, K. Etessami, and M. Yannakis. Inference of message sequence charts. IEEE Transactions on Software Engineering, 2003.

R. Alur, S. Chaudhuri, K. Etessami, S. Guha, and M. Yannakakis. Compression of partially ordered strings. 15th International Conference on Concurrency Theory, 2003.

R. Alur, F. Ivancic, J. Kim, I. Lee, and O. Sokolsky. Generating embedded software from hierarchical hybrid models. ACM Symposium on Languages, Compilers, and Tools for Embedded Systems, 2003.

R. Alur, S. La Torre, and P. Madhusudan. Modular strategies for infinite games on recursive game graphs. 15th International Conference on Computer-Aided Verification, 2003.

R. Alur, S. La Torre, and P. Madhusudan. Modular strategies for recursive game graphs. Ninth International Conference on Tools and Algorithms for the Construction and Analysis of Systems, 2003.

R. Alur, S. La Torre, and P. Madhusudan. Playing games with boxes and diamonds. 14th International Conference on Concurrency Theory, 2003

R. Alur, T. Dang, and F. Ivancic. Counter-example guided predicate abstraction of hybrid systems. Ninth International Conference on Tools and Algorithms for the Construction and Analysis of Systems, 2003.

R. Alur, T. Dang, and F. Ivancic. Progress on reachability analysis of hybrid systems using predicate abstraction. Sixth International Workshop on Hybrid Systems: Computation and Control, 2003.

P. Madhusudan, W. Nam, and R. Alur. Symbolic computational techniques for solving games. Workshop on Bounded Model Checking, 2003.

R. Alur, C. Belta, F. Ivancic, V. Kumar, H. Rubin, J. Schug, O. Sokolsky, and J. Webb. Visual programming for modeling and simulation of biomolecular regulatory networks. International Conference on High Performance Computing, 2002.

R. Alur, M. McDougall and Z. Yang. Exploiting behavioral hierarchy for efficient model checking. 14th International Conference on Computer-Aided Verification, 2002.

R. Alur, T. Dang, and F. Ivancic. Reachability analysis of hybrid systems via predicate abstraction. Fifth International Workshop on Hybrid Systems: Computation and Control, 2002.

A. Goodloe, M. McDougall, C. Gunter and R. Alur. Predictable programs in barcodes. International Conference on Compilers, Architecture and Synthesis of Embedded Systems (CASES), 2002.


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P. S. Ayyaswamy

Asa Whitney Professor of Dynamical Engineering; Graduate Group Chair
Email: ayya at seas.upenn.edu
Personal Website

Research Interests:
Interconnection processes in microelectronic packaging technology: wire and die bonding: We have been investigating the melting of metals and alloys by arc-discharges and subsequent solidification. This is in regard to microelectronic interconnection by wire bonding. Recently we have extended these studies to include plasma spraying/etching. With regard to die-bonding, we have established new results for the flow of yield stress fluids. Microgravity fluid mechanics, mass transfer, and biotechnology: Here our objective has been to determine the mechanisms responsible for changes in osteoblast behavior under simulated microgravity conditions by employing experimental and numerical/analytical methods. We have conducted in vitro experiments with osteoblasts in the rotating wall vessels to assess the effects of both gravity and hydrodynamic shear stresses on the function of bone cells. Convective heat and mass transfer in the presence of a phase-change: We have been investigating forced convection effects on condensation, evaporation and combustion. Study of transport associated with moving liquid drops is emphasized. We are also studying the effect of electric fields on flames under normal and microgravity conditions.

Selected Recent Publications:
P. Ayyaswamy, M. Parker and B. Drolen Study of a Loop Heat Pipe (LHP) for Spacecraft Thermal Control: Part III: Numerical Simulation. (submitted)

P. Ayyaswamy, M. Parker and B. Drolen. Studies with a Loop Heat Pipe (LHP) for Spacecraft Thermal Control: Part IV: Experiments aboard Space Shuttle Columbia Mission of 1997. (submitted)

P. Ayyaswamy, M. Parker and B. Drolen.Ground based Studies with a Loop Heat Pipe (LHP) for Spacecraft Thermal Control: Part II: Experiments under Ambient Conditions. J. Thermophysics and Heat Transfer, 2005.

M.A. Bucaro, J. Fertala, CS Adams, et al. Bone cell survival in microgravity – Evidence that modeled Microgravity increases osteoblast sensitivity to apoptogens. Transport Phenomena in Microgravity, 1027: 64-73. 2004.

P. Ayyaswamy, M. Parker and B. Drolen. Ground based Studies with a Loop Heat Pipe (LHP) for Spacecraft Thermal Control: Part I: Vacuum Chamber Tests. J. Thermophysics and Heat Transfer, 2004.

K. Mukukndakrishnan, P. Ayyaswamy, M. Risbud, H. Hu, and I. Shapiro. Modeling of Phosphate Ion Transfer to the Surface of Osteoblasts Under Normal Gravity and Simulated Microgravity Conditions. Annals of the New York Academy of Sciences, 2004.

P. Ayyaswamy, S. S. Sripada and I. M. Cohen. Melting of a wire anode followed by solidification: A three-phase moving interface problem. J. Heat Transfer, Trans. ASME, 125, No. 4, 661-668, 2003.

P. Ayyaswamy. Bioactive, degradable composite microspheres: effect of filler material on surface reactivity. Microgravity Transport Processes in Fluid, Thermal, Biological and Materials Sciences, Annals of the New York Academy of Sciences,79, Ed: S.S. Sadhal, 974, 556-564, 2002.

P. Ayyaswamy, I.M. Cohen. Low Energy Plasma Heat Transfer as Applied to Microelectronic Packaging. Annual Review of Heat Transfer, XII, 27-78, 2002.

P. Ayyaswamy, I.M. Cohen. Low energy plasma heat transfer in microelectronic manufacturing. Proc. Intl. Symp. Recent trends in heat and mass transfer, Indian Institute of Technology, Guwahati, India, 2002.

P. Ayyaswamy, K. Mukundakrishnan and I. M. Cohen. Electric field effects on ion transport in heated flows.Fifth ISHMT/ASME Heat and Mass Transfer Conference, Kolkata, India, 2002.

P. Ayyaswamy, Ed. Chang-Lin Tien, V. Prasad, and F. Incropera. Low Energy Plasma Heat Transfer as Applied to Microelectronic Packaging.
in Annual Review of Heat Transfer, vol. XII 2002.


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Norman I. Badler

Professor of Computer and Information Science; Director, Center for Human Modeling and Simulation; Associate Dean of the School of Engineering and Applied Science
Email: badler at seas.upenn.edu
Personal Website

Research Interests:
Computer graphics, human movement simulation, embodied agents, three-dimensional virtual and augmented reality interaction; and relationships between human movement, natural language, instructions and communication.

Selected Recent Publications:
L. Zhao, Y. Liu, and N. Badler. Applying empirical data on upper torso movement to real-time collision-free reach tasks. SAE Digital Human Modeling Conference, Iowa City, IA, 2005.

N. Badler, J. Allbeck, S.-J. Lee, R. Rabbitz, T. Broderick, and K. Mulkern. New behavioral paradigms for virtual human models. SAE Digital Human Modeling Conference, Iowa City, IA, 2005.

L. Zhao and N. Badler. Acquiring and Validating Motion Qualities from Live Limb Gestures. Graphical Models, 2005.

J. Allbeck and N. Badler. Creating Embodied Agents with Cultural Context. In R. Trappl and S. Payr (Eds.), Agent Culture: Designing virtual characters for a multi-cultural world. New York: Lawrence Erlbaum Associates, 2004.

J. Allbeck and N. Badler. Representing and Parameterizing Agent Behaviors. Life-like Characters: Tools, Affective Functions and Applications. Helmut Prendinger and Mitsuru Ishizuka, Ed. Springer, Germany, 2003.

K. Ashida and N. Badler. Feature preserving manifold mesh from an octree. Solid Modeling and Applications 2003, pp. 292-297.

Y. Liu and N. Badler. Real-Time Reach Planning for Animated Characters Using Hardware Acceleration. Computer Animation and Social Agents, IEEE Computer Society, New Brunswick, NJ, May 2003, pp. 86-93.

A. Bloomfield, Y. Deng, P. Rondot, J. Wampler, D. Harth, M. McManus, N. Badler. A Taxonomy and Comparison of Haptic Actions for Disassembly Tasks. IEEE Virtual Reality Conf., LA, CA, March 2003, pp. 225-231.

J. Allbeck and N. Badler. Embodied Autonomous Agents. In Handbook of Virtual Environments. K. Stanney, ed., Lawrence Erlbaum Associates, 2002, pp. 313-332.

N. Badler and J. Allbeck. Towards behavioral consistency in animated Agents. Deformable Avatars, Kluwer Academic Publishers, N. Magnenat-Thalmann and D. Thalmann, eds., 2001, pp. 191-205.

J. Allbeck and N. Badler. Toward representing agent behaviors modified by personality and emotion."Workshop on Embodied Conversational Agents -Let's specify and evaluate them! at AAMAS 2002, Bologna, Italy.

J. Allbeck, K. Kipper, C. Adams, W. Schuler, E. Zoubanova, N. Badler, M. Palmer, and A. Joshi. ACUMEN: Amplifying Control and Understanding of Multiple ENtities. Autonomous Agents and Multi-Agent Systems, July 2002, Bologna, Italy, pp. 191-198.

N. Badler. LiveActor: A virtual training environment with reactive embodied agents. Workshop on Intelligent Human Augmentation and Virtual Environments, Univerity of North Carolina at Chapel Hill, Oct. 2002.

N. Badler, J. Allbeck, and R. Bindiganavale. Describing human and group movements for interactive use by reactive virtual characters. Army Science Conference, 2002

N. Badler, J. Allbeck, L. Zhao, and M. Byun. Representing and parameterizing agent behaviors. Proc. Computer Animation, IEEE Computer Society, 2002, Geneva, Switzerland, pp. 133-143.

N. Badler, C. Erignac, and Y. Liu. Virtual humans for validating maintenance procedures. Comm. of the ACM, July 2002, pp. 57-63.

M. Byun and N. Badler. FacEMOTE: Qualitative parametric modifiers for facial animations. Symposium on Computer Animation, San Antonio, TX, July 2002, pp. 65-71.

J. Gratch, J. Rickel, E. Andre, N. Badler, J. Cassell, and E. Petajan. Creating interactive virtual humans: Some assembly required. IEEE Intelligent Systems, 2002.

S. Lee, J. Badler, and N. Badler. Eyes alive. ACM Transactions on Graphics - Special Issue, Proceedings of SIGGRAPH 2002, San Antonio, TX, pp. 637-644.

H. Shin, J. Allbeck, D. M. Elliott, and N. I. Badler. Modeling a deformable human arm for constrained reach analysis.Proc. Digital Human Modeling Conference, Munich, Germany, June 18-20, 2002, VDI Berichte 1675, pp. 217-228, VDI-Gesellschaft Fahrzeugund Verkehrstechnik - Düsseldorf: VDI Verlag and SAE-International.


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John L. Bassani

Richard H. and S. L. Gabel Professor of Mechanical Engineering; Professor of Materials Science and Engineering
Email: bassani at seas.upenn.edu
Personal Website

Research Interests:
Plastic Deformation of Crystals: Plastic deformation of crystalline solids, including ordered compounds and multiphase materials, is investigated. Strain localization is studied under multiple slip deformations. Nonlocal effects that give rise both to size-dependent phenomena and patterning of localized flow are also investigated utilizing both continuum theories and discrete dislocation simulations. Interface Mechanics: The relationship between atomic-level (discrete) and continuum properties of heterogeneous solids is studied. In particular, the spatially-varying (anisotropic) elastic properties of interfaces and their effect on lattice vibrations (phonons) and localized waves are investigated. The implication of distinct atomic structures on interface diffusion is being explored in relation to another current interest in decohesion along interfaces. Fracture: Fracture along interfaces is studied from several perspectives with recent interest in dynamic embrittlement arising from impurity diffusion. Atomistic simulations are utilized to guide the continuum modeling of this thermodynamically non-equilibrium process. Models for crack propagation are being developed and compared with experiments.

Selected Recent Publications:
Vitek, V., Mrovec, M., Bassani, J.L. Influence of non-glide stresses on plastic flow: From atomistic to continuum modeling. Materials Science and Engineering A, v 365, n 1-2, Jan 25, 2004, p 31-37.

Acharya, A., Bassani, J.L., Beaudoin, A. Geometrically necessary dislocations, hardening, and a simple gradient theory of crystal plasticity. Scripta Materialia, v 48, n 2, 13 Jan. 2003, p 167-72.

Braginsky, M., Bassani, J. L. and Vitek, V. Elastic Properties of Heterogeneous Atomic Structures. Philosophical Magazine, 2002.

Mishin, Y., Sofronis, P., Bassani, J.L. Thermodynamic and kinetic aspects of interfacial decohesion. Acta Materialia, v 50, n 14, 16 Aug. 2002, p 3609-22.


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Haim H. Bau

Professor of Mechanical Engineering and Applied Mechanics; Professor of Electrical and Systems Engineering
Email: bau at seas.upenn.edu
Personal Website

Research Interests:
Active Control of Flow Patterns: Often, in industrial processes and in propulsion, fluids behave in an undesirable way. For example, oscillatory convection in a crystal melt leads to defects in the crystal. Conversely, in chemical reactions and combustion, it is desirable to maintain chaotic and turbulent flows to achieve vigorous mixing. Applying ideas of control theory, we are studying experimentally and theoretically the feasibility of modifying flow patterns so as to achieve optimal flow conditions for various processes. For example, with the use of a feedback controller effecting small perturbations in boundary conditions, we have been able to maintain laminar flows under conditions in which chaotic flows would normally occur and conversely, induce chaos under conditions when the flow would normally tend to be laminar. Micro-fluidics: In experiment and theory, we are studying transport processes in very small devices and we are developing various microfluidic components. The objective is to develop the necessary science base needed to accommodate biological and chemical laboratories on a "chip." Among other things, we are developing micro mixers, inertial separators of particles, thermal cyclers, and electrophoretic cells. Most recently, our efforts have focused on constructing MEMS devices on low-temperature, co-fired, ceramic tapes.

Selected Recent Publications:

Kim, B.M., Murray, T., and Bau, H.H. The fabrication of integrated carbon pipes with sub-mircon diameters. Nanotechnology, v 16, n 8, August 1 2005, p 1317-1320.

Qian, S. and Bau, H.H. Magnetrohydrodynamic flow of RedOx electrolyte. Physics of Fluids. 2005.

Kim, B.M., Qian, S., and Bau, H.H. Filling carbon nanotubes with particles. Nano Letters 5, 2005.

Qian, S. and Bau, H.H. Magneto-hydrodynamic stirrer for stationary and moving liquids. Sensors and Actuators B-Chemical 106, 2005.

Qian, S., Burger, R., and Bau, H.H. Analysis of sedimentation biodetectors. Chemical Engineering Science, 2005.

Kim, B.M., Sinha S., and Bau, H.H. Optical microscope study of liquid transport in carbon nanotubes. Nano Letters 4, 2004.

Qian, S. and Bau, H.H. Analysis of lateral flow biodetectors: competitive format. Analytical Biochemistry, 2004.

Eyoy, S., DiLello N., Bau, H.H., et al. Dielectrophoretic assembly and integration of nanowire devices with functional CMOS operating circuitry. Microelectric Engineering, 2004.

Liu, Hui, Bau, Haim H. The dialectrophoresis of cylindrical and spherical particles submerged in shells and in semi-infinite media. Physics of Fluids, v 16, n 5, May, 2004, p 1217-1228.

Hui Liu, Bau, H.H., Hu, H. On the translation of a cylinder in a long tube. Physics of Fluids, v 16, n 4, April 2004, p 998-1007.

Chen, Z., Qian, S., Abrams, W.R., Malamud, D., and Bau, H.H. Thermosiphon-based PCR reactor: experiment and modeling. Analytical Chemistry, 2004.

Liu, Hui, Bau, Haim H., Hu, Howard H. Electrophoresis of concentrically and eccentrically positioned cylindrical particles in a long tube. Langmuir, v 20, n 7, Mar 30, 2004, p 2628-2639.

Qian, S. and Bau, H.H. A mathematical model of lateral flow bioreactions applied to sandwich assays. Analytical Biochemistry, 2003.

Yi, Mingqiang, Bau, Haim H. The kinematics of bend-induced mixing in micro-conduits. International Journal of Heat and Fluid Flow, v 24, n 5, October, 2003, p 645-656.

Yu Xiang, Bau, H.H. Complex magnetohydrodynamic low-Reynolds-number flows. Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), v 68, n 1, July 2003, p 16312-1-11.

Bau, H.H., Jianzhong Zhu, Shizhi Qian, Yu Xiang. A magneto-hydrodynamically controlled fluidic network. Sensors and Actuators B (Chemical), v B88, n 2, 15 Jan. 2003, p 205-16.

Bau, Haim H., Zhu, Jianzhong, Qian, Shizhi, Xiang, Yu. A magneto-hydrodynamic micro fluidic network. American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FED, v 258, 2002, p 407-414.

Mingqiang Yi, Shizhi Qian, Bau, H.H. A magnetohydrodynamic chaotic stirrer. Journal of Fluid Mechanics, v 468, 10 Oct. 2002, p 153-77.

Qian, Shizhi, Bau, Haim H. Chaotic electroosmotic flow. American Society of Mechanical Engineers, Micro-Electromechanical Systems Division Publication (MEMS), 2002, p 405-412

Shizhi Qian, Jianzhong Zhu, Bau, H.H. A stirrer for magnetohydrodynamically controlled minute fluidic networks. Physics of Fluids, v 14, n 10, Oct. 2002, p 3584-92.

Qian, Shizhi, Bau, Haim H. A chaotic electroosmotic stirrer. Analytical Chemistry, v 74, n 15, Aug 1, 2002, p 3616-3625.

Mingqiang Yi, Bau, H.H., Howard Hu. Peristaltically induced motion in a closed cavity with two vibrating walls. Physics of Fluids, v 14, n 1, Jan. 2002, p 184-97.

Jihua Zhong, Mingqiang Yi, Bau, H.H. Magneto hydrodynamic (MHD) pump fabricated with ceramic tapes. Sensors and Actuators A (Physical), v A96, n 1, 31 Jan. 2002, p 59-66.


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George Biros

Assistant Professor of Mechanical Engineering and Applied Mechanics; Assistant Professor of Computer and Information Science
Email: biros at seas.upenn.edu
Personal Website

Research Interests:
Computational science and engineering; optimization; bioengineering; parallel computing.

Selected Recent Publications:
Akcelik V, Biros G, Draganescu A, Hill J, Ghattas O, and Van Bloeman Waanders B. Dynamic data-driven inversion for terascale simulations: real-time identification of airborne contaminants.

Biros G. and Ghattas O. Parallel Lagrange-Newton-Krylov-Schur Methods for PDE-Constrained Optimization. Part II: The Lagrange-Newton solver, and its Application to Optimal Control of Steady Viscous Flows.

Biros G. and Ghattas O. Parallel Lagrange-Newton-Krylov-Schur Methods for PDE-Constrained Optimization. Part I: the Krylov-Schur Solver. Siam Journal on Scientific Computing, to appear.

Ying LX, Biros G, Zorin D. A kernel-independent adaptive fast multipole algorithm in two and three dimensions. JOURNAL OF COMPUTATIONAL PHYSICS 196 (2): 591-626 MAY 20 2004.

Biros G, Ying LX, Zorin D. A fast solver for the Stokes equations with distributed forces in complex geometries. JOURNAL OF COMPUTATIONAL PHYSICS 193 (1): 317-348 JAN 1 2004.

Ying L., Biros G., Zorin D., and Harper L. A New Parallel Kernel-Independent Fast Multipole Method. The SCXY Conference Series, November 2003.

Akcelik V., Bielak J, Bros G, Pnomeritakis I, Fernandez A., Ghattas O., Kim E.J. , O'Hallaron D., and Tu T.High-resolution Forward and Inverse Earthquake Modeling on Terascale Computers
The SCXY Conference Series, November 2003.

Ying L., Biros G.,and Zorin D. A Kernel-Independent Adaptive Fast Multipole Method In Two and Three Dimensions. Journal of Computational Physics, 2003.

Akcelik, V., Biros, G., Ghattasa, O., Long, K.R., Van Waanders, B.B. A variational finite element method for source inversion for convective-diffusive transport. Finite Elements in Analysis and Design, v 39, n 8, May 2003, p 683-705.

Akcelik V., Biros G. and Ghattas O. Parallel Multiscale Gauss-Newton-Krylov Methods for Inverse Wave Propagation. The SCXY Conference Series, November 2002.

Biros G., Ying L., and Zorin D. An Embedded Boundary Integral Equation Solver for the Unsteady Incompressible Navier-Stokes Equations, November 2002.

Biros G., Ying L. and Zorin D. An Embedded Boundary Integral Equation Solver for the Stokes Equations. Journal of Computational Physics, June 2002.

Biros G., Ying L. and Zorin D. The Embedded Boundary Integral Equation Solver for the Incompressible Navier-Stokes equations. International Association for Boundary Element Methods Symposium, The University of Texas at Austin, TX, May 28-30, 2002.


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Matthew Blaze

Associate Professor of Computer and Information Science
Email: blaze at cis.upenn.edu
Personal Website

Research Interests:
Secure Systems and Cryptology - My research focuses on the architecture and design of secure systems based on cryptographic techniques, analysis of secure systems against practical attack models, and on finding new cryptographic primitives and techniques. This work has led directly to several new cryptographic concepts, including: "Remotely-Keyed Encryption," which allows the use of inexpensive, low-bandwidth secure hardware to protect high-bandwidth communication and stored data, "Atomic Proxy Cryptography," which allows re-encryption by untrusted third parties, and "Master-Key Encryption," which provides a systematic way to design (and study) ciphers with built-in "back doors." I am especially interested in the use of encryption to protect insecure systems such as the Internet. I was a designer of swIPe, a predecessor of the now standard IPSEC protocol for protecting Internet traffic. Another project, CFS, investigated and demonstrated the feasibility of including encryption as file system service. Recently, I've applied cryptologic techniques to other areas, including the analysis of physical security systems; this work yielded a powerful and practical attack against virtually all commonly used master-keyed mechanical locks. Trust Management: I coined the term, and am one of the inventors of, Trust Management, which provides the abstract layer in which a system decides whether to allow some potentially dangerous action. This work has led to two trust management languages, KeyNote and PolicyMaker, that provide tools for specifying policy, delegating authority, and controlling access. In addition to providing a useful framework for studying and proving security properties of distributed systems, our tools have been used to build powerful policy control mechanisms into several important applications, including the OpenBSD IPSEC implementation. Technology and Public Policy: Cryptology and computer security have important relationships to vital areas of public policy, and my work has touched on these in several ways. In 1994, I discovered a serious flaw in the US Government's "Clipper" encryption system, which had been proposed as a mechanism for the public to encrypt their data in a way that would still allow access by law enforcement. I have edited several influential reports on encryption policy, including the 1998 study of "key escrow" systems that demonstrated that such systems are inherently less secure and more expensive than systems without such a feature. This work contributed to the recent shift in U.S. encryption policy. More recently, I have been active in the analysis of the FBI's "Carnivore'' Internet wiretap system. I have testified before various comittees of the US Congress and European Parliament several times, providing technical perspective on the problems surrounding law enforcement and intelligence access to communications traffic and computer data.

Selected Recent Publications:
M. Blaze. Toward a broader view of security protocols. 12th Cambridge International Workshop on Security Protocols. Cambridge, UK, April 2004.

M. Blaze. Cryptology and Physical Security: Rights Amplification in Master-Keyed Mechanical Locks. March 2003. IEEE Security and Privacy. March/April 2003.

Blaze, M., ed. Financial Cryptography. 6th International Conference, FC 2002. Revised Papers (Lecture Notes in Computer Science Vol.2357). Springer-Verlag, 2003, viii+299 pp.

Blaze, M., Ioannidis, J., Ioannidis, S., Keromytis, A.D., Nikander, P., Prevelakis, V. TAPI: transactions for accessing public infrastructure. Personal Wireless Communications. IFIP-TC6 8th International Conference, PWC 2003. Proceedings (Lecture Notes in Comput. Sci. Vol.2775), 2003, p 90-100

W. Aiello, S. M. Bellovin, M. Blaze, R. Canetti, J. Ioannidis, A. D. Keromytis, and O. Reingold. Efficient, DoS-Resistant, Secure Key Exchange for Internet Protocols." In Proc. ACM Computer and Communications Security (CCS) Conference. November 2002, Washington, DC. (pp 48-58).

Blaze, M., Ioannidis, J., Keromytis, A.D. Trust management for IPsec. ACM Transactions on Information and Systems Security, v 5, n 2, May 2002, p 95-118.


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Kwabena A. Boahen

Associate Professor of Bioengineering; Assistant Professor of Electrical and Systems Engineering; Member of Institute for Medicine and Engineering (secondary appointment in Electrical and Systems Engineering)
Email: boahen at seas.upenn.edu , kwabena at neuroengineering.upenn.edu
Personal Website   |   Research Website

Research Interests:
Nature has evolved computational structures that use energy a million times more efficiently than human-engineered computers do and the vertebrate visual system has a dedicated front-end (the retina) that encodes information a thousand times less redundantly than CCD cameras. Engineers are far from matching either the efficiency of neural computation or the effectiveness of neural coding. By studying how nature co-optimizes these structural and functional constraints, we seek to engineer sensorimotor systems that match the efficiency and the effectiveness of their biological counterparts.

To achieve this goal, we recreate the structure and function of neural systems in silicon using very large scale integration (VLSI) complementary metal–oxide–semiconductor (CMOS) technology. To build these neuromorphic systems, we proceed from the device level, through the circuit level, to the system level. At the device level, we mimic electrodiffusion of ions through membrane channels with electrodiffusion of electrons through transistor channels. At the circuit level, we derive minimal implementations of synaptic interaction, dendritic integration, and active membrane behavior. At the system level, we synthesize the spatiotemporal dynamics of the cochlea, the retina, and early stages of cortical processing.

Selected Recent Publications:

Zaghloul, K.A. and Boahen, K.A. A silicon model of the mammalian retina. Proceedings of the National Academy of Science. In Review.

Zaghloul, K.A. and Boahen, K.A. An on-off log-domain circuit that recreates temporal filtering in the inner retina. IEEE Transactions on Circuits and Systems II. In Review.

Zaghloul, K.A. and Boahen, K.A. Reproducing optic nerve signals in a retinomorphic chip I: Outer and inner retina models. IEEE Transactions on Biomedical Engineering. In Review.

Zaghloul, K.A. and Boahen, K.A. An on-off log-domain circuit that recreates adaptive filtering in the retina. IEEE Transactions on Circuits and Systems I. In press.

Boahen, K.A. Neuromorphic Microchips. Scientific American, 2005.

Choi, T.Y.W., Merolla, P.A., Arthur, JV. Boahen, K. Neuromorphic implementation of orientation hypercolumns. IEEE Transactions on Circuits and Systems I, 2005.

Zaghloul, K.A., Boahen, K., and Demb, J.B. Contrast adaptation in subthreshold and spiking responses of mammalian Y-type retinal ganglion cells. Journal of Neursocience, 2005.

Zaghloul, K.A. and Boahen, K.A. An ON-OFF log domain circuit that recreates adaptive filtering in the retina. IEEE Transactions on Circuits and Systems I, 2005.

Boahen, K.A. A burst-mode word-serial address-event channel-III. Analysis and Testing. IEEE Transactions on Circuits and Systems I, 2004.

Boahen, K.A. A burst-mode word-serial address-event channel-II. Receiver design. IEEE Transactions on Circuits and Systems I, 2004.

Boahen, K.A. A burst-mode word-serial address-event channel-I. Transmitter design. IEEE Transactions on Circuits and Systems I, 2004.

Arthur, J.V. and Boahen, K.A. Recurrently connected silicon neurons with active dendrites for one-shot learning. International Joint Conference on Neural Networks, 2004.

Merolla, P. and Boahen, K.A. A recurrent model of orientation maps with simple and complex cells. Advances in Neural Information Processing Systems, 2004.

Choi, T., Shi, B. and Boahen, K.A. A multi-chip model of cortical orientation hypercolumns. IEEE International Symposium on Circuits and Systems, 2004.

Zaghloul, K.A., Boahen, K. Optic nerve signals in a neuromorphic chip II: testing and results. IEEE Transactions on Biomedical Engineering, v 51, n 4, April 2004, p 667-75.

Zaghloul, K.A., Boahen, K. Optic nerve signals in a neuromorphic chip I: Outer and inner retina models. IEEE Transactions on Biomedical Engineering, v 51, n 4, April 2004, p 657-66

Choi, T.Y.W., Shi, B.E., Boahen, K.A. An ON-OFF orientation selective address event representation image transceiver chip. IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, v 51, n 2, Feb. 2004, p 342-53.

Choi, T.Y.W., Shi, B.E., Boahen, K. An orientation selective 2D AER transceiver. Proceedings of the 2003 IEEE International Symposium on Circuits and Systems (Cat. No.03CH37430), 2003, pt. 4, p IV-800-3 vol.4.

Wen, B., Boahen, K. A Linear Cochlear Model with Active Bi-directional Coupling. Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, v 3, 2003, p 2013-2016.

Hynna, K.M., Boahen, K.A. A silicon implementation of the thalamic low threshold calcium current. Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, v 3, 2003, p 2228-2231.

Zaghloul, K.A., Boahen K., Demb JB. Different circuits for ON and OFF retinal ganglion cells cause different contrast sensitivities. Journal of Neuroscience. 23(7):2645-54, 2003 Apr 1.

Culurciello, E., Etienne-Cummings, R., Boahen, K.A. A biomorphic digital image sensor. IEEE Journal of Solid-State Circuits, v 38, n 2, Feb. 2003, p 281-94.

Taba, B. and Boahen, K. Topographic map formation by silicon growth cones. Advances in Neural Information Processing Systems, 2003.

Shi, B.E., Boahen, K. Competitively coupled orientation selective cellular neural networks. IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, v 49, n 3, March 2002, p 388-94.

Shi, Bertram E., Choi, Thomas Yu Wing, Boahen, Kwabena. On-off differential current-mode circuits for Gabor-type spatial filtering. Proceedings - IEEE International Symposium on Circuits and Systems, v 2, 2002, p II/724-II/727.

Boahen, K. A retinomorphic chip with parallel pathways: encoding INCREASING, ON, DECREASING, and OFF visual signals. Analog Integrated Circuits and Signal Processing, v 30, n 2, Feb. 2002, p 121-35.


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Eric T. Boder

Assistant Professor of Chemical and Biomolecular Engineering
Email: boder at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Development and optimization of proteins as therapeutic agents; engineering the immune response; biophysics and structural biology of immunological receptors; high affinity protein binding. Proteins are naturally occurring polymers comprised of amino acid subunits. The advantage of these molecules is their ability to catalyze a wide range of complex chemistries and engage in countless exquisitely specific molecular interactions, yet each protein is itself constructed from a single synthetic chemistry and its function is perfectly contained within a simple genetic code. The ability of this class of molecule to perform highly complex tasks, combined with their relative ease of synthesis by microorganisms, has spurred the development of an industry pursuing the use of proteins in separations, diagnostics, and numerous medical therapies. Protein pharmaceuticals, also called biopharmaceuticals, represent a rapidly developing product area in industry. In many cases, the extreme specificity of molecular interations required to inhibit certain disease states has limited the success of small organic pharmaceuticals in treatment. Protein reagents have the potential to overcome this obstacle; however, the utility of proteins as therapeutic agents has been limited by the lack of a quantitative engineering approach to developing proteins with the appropriate molecular properties. My goal is to develop a program of research addressing this need. This research must consider several critical points: 1. Selection of a molecular scaffold with properties suitable for the intended application (e.g, tissue penetration properties, thermal stability); 2. Development of protein engineering processes for quantitatively altering the functional properties of the chosen reagent to optimize for the specific application; 3. Quantitative analysis of the relevant molecular properties and combination of this knowledge with protein engineering processes for molecular design. A particular target application of this research is engineering the immune response. Numerous devastating diseases result from destruction of the body's own tissues due to attack by the cellular immune system (autoimmunity). Misidentification of self in autoimmunity and immunological attack of transplanted tissues, as well as failure of the immune system to identify certain harmful entities (e.g., certain viruses or tumor cells), is essentially a problem of molecular recognition. Inhibiting undesirable immune responses or stimulating immune responses against novel targets are problems most likely to be solved by taking advantage of the unique properties of engineered protein reagents. Research in this area makes use of tools from molecular biology, protein chemistry, and biophysics.

Selected Recent Publications:
Parthasarathy R, Subramanian S, Boder ET, Discher DE. Post-translational regulation of expression and conformation of an
immunoglobulin domain in yeast surface display. Biotechnol Bioeng. 2005 Sep 13.

Boder ET, Bill JR, Nields AW, Marrack PC, Kappler JW. Yeast surface display of a noncovalent MHC class II heterodimer complexed with antigenic peptide. Biotechnol Bioeng. 2005 Sep 9.

Park, S., Boder, E.T., and Saven, J.G. Modulating the DNA affinity of Elk-1 with computationally selected mutations. Journal of Molecular Biology, 2005.

Park, S.J., Kono, H., Wang, W., Boder, E.T., and Saven, J.G. Progress in the development and application of computational methods for probabilistic protein design. Computers and Chemical Engineering, 2005.

Dahl, K.N., Photos, P.J., Parthasarathy, R., Westhoff, C.M., Boder, E.T., Discher, D.E. Marker of self" CD47: From erythrocyte to drug delivery. Annual International Conference of the IEEE Engineering in Medicine and Biology, 2002.


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Daniel K. Bogen

Associate Professor of Bioengineering; Associate Professor of Bioengineering in Medicine; Associate Professor of Rehabilitation Medicine; Associate Professor of Bioengineering in Pediatrics
Email: dan at seas.upenn.edu
Personal Website

Research Interests:
My primary research interest is in pediatric rehabilitation engineering-developing new technology to diagnose and treat disabled children. I am especially interested in cognitive rehabilitation of children with brain injury and other neurological or cognitive disorders. This work involves the development of new kinds of pediatric user-interfaces to biomedical devices-interfaces which are appealing to children, and which allow the children to operate diagnostic and therapeutic instruments.

Selected Recent Publications:

Yoo, T.D., JungHyunHan, Eunyoung Kim, and Bogen, D.K. Geometrical analysis for assistive medical device design. Computational and Information Science. First International Symposium, CIS 2004.

Berger, R.P., Bogen, D., Dulani, T., and Broussard, E. Implementation of a program to teach pediatric residents and faculty about domestic violence. Archives of Pediatrics & Adolescent Medicine, 2002.


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Dawn A. Bonnell

Trustees Chair Professor of Materials Science and Engineering; Professor of Bioengineering; Director of Nano-Bio Interface Center
Email: bonnell at lrsm.upenn.edu
Personal Website   |   Research Website

Research Interests:

Research in the Bonnell Group is focused on the fundamental basis of property variations at nanometer length scales in complex materials and exploiting these variations to make functional nanosystems.

The length scale may be due to the size of the system as in a 3 nm metal cluster, or to the vicinity of a defect such as an atomic interface in a solid or a bonding defect in a molecular wire. The focus on complex materials enables a large range of functional behavior. Our studies involve transition metal oxides, organic and inorganic ferroelectric compounds, functionalized organic and biological molecules, and non conventional semiconductors. New methods of fabrication are required to produce composites of these constituents that are useful for molecular electronics or biochemical sensors.

Selected Recent Publications:

Staii, C., Johnson, A.T. Jr., Shao, R., and Bonnell, D.A. High frequency scanning gate microscopy and local memory effect of carbon nanotube transistors. Nano Letters 5, 2005.

Lei, X., Li, D.B., Shao, R., and Bonnell, D.A. In situ deposition/positioning of magnetic nanoparticles with ferroelectric nanolithography. Journal of Materials Research, 2005.


Strachan, D.R., Smith, D.E., Johnston, D.E., et al. Controlled fabrication of nanogaps in ambient environment for molecular electronics. Applied Physics Letters, 2005.

Kalinin, S.V., Shao, R., and Bonnell D.A. Local phenomena in oxides by advanced scanning probe microscopy. Journal of the American Ceramic Society, 2005.

Shao, R. and Bonnell, D.A. Probing electrical transport across oxide interfaces by noncontact atomic force microscopy. Applied Physics Letters, 2004.

Kalinin, S.V., Gruyerman, A., and Bonnell, D.A. Quantitative analysis of nanoscale switching in SrBi2Ta 2O9 thin films by piezoresponse force microscopy. Applied Physics Letters, 2004.

Lei, X., Kalinin, S., Hu, Z., and Bonnell, D.A. Ferroelectric lithography of multicomponent nanostructure. Ceramic Transactions, 2004.

Shao, R., Vavro, J., and Bonnell, D.A. Low-temperature study of nonlinear transport across oxide grain boundaries. Applied Physics Letters, 2004.

Shao, R., and Bonnell, D.A. Scanning probes of nonlinear properties in complex materials. Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers, 2004.

Dawn A. Bonnell, Rui Shao (2003) Principles of Basic and Advanced Scanning Probe Microscopy. NATO ASI Series Klewer Acad Pub.

D. Bonnell, F. Zypmann. (2003) Spatially Resolved Characterization of Local Phenomena in Materials and Nanostructures. MRS Proceedings Volume 738.

Sergei V. Kalinin and Dawn A. Bonnell. (2003) Scanning Probe Microscopy Of Piezoelectric And Transport Phenomena In Electroceramic Materials. NATO ASI Series Klewer Acad Pub.

R. Shao, D. Bonnell (2003) NanoImpedance Spectroscopy of Electrically Active Interfaces. Proc. of the Materials Research Society Symposium, 738 163-68.

D. A. Bonnell, S. Kalinin. (2002) Local Polarization, Charge Compensation and Chemical Interactions on Ferroelectric Surfaces: A Route Toward New Nanostructures
Proc. of the Materials Research Society Symposium, Vol. 688, Ferroelectric Thin Films X.

M. Freitag, S. Kalinin, D. Bonnell, A. T. Johnson (2002) Role Of Defects In Electronic Transport Through Semiconducting Single-Wall Carbon Nanotubes.Phys Rev Letters 89 216801.

A.T. Johnson, M. Freitag, M. Radosavljevic, S.V. Kalinin, and D.A. Bonnell. (2002) Role of Defects in Carbon Nanotube Circuits International. Journal of Nanoscience 1, 247 - 254.

S. Kalinin, D. Bonnell (2002) Contrast Mechanism Maps For Piezoresponse Force Microscopy. J. Mat. Res., 17 936-939.

S. Kalinin, D. A. Bonnell (2002) Imaging Mechanism Of Piezoresponse Force Microscopy Of Ferroelectric. Physical Review B 64 125408.

S. Kalinin, D. A. Bonnell (2002) Scanning Impedance Microscopy: From Impedance Spectra To Impedance Images. Microscopy Today 2 22.

S. Kalinin, D. A. Bonnell (2002). Scanning Impedance Microscopy: From Impedance Spectra to Impedance Imaging. Proc. of the Materials Research Society Symposium Vol. 699.

S. Kalinin, D. A. Bonnell. (2002) Scanning Impedance Microscopy of an Active Schottky Barrier Diode. J. Applied Physics, 91 832-39.

Sergei Kalinin, D. Bonnell, T. Alvarez, X. Lei, Z. Hu, J. Ferris, Q. Zhang, S. Dunn. (2002) Atomic Polarization, Charge Compensation and Local Reactivity on Ferroelectric Surfaces: a new route toward complex nanostructures. Nano Letters 2 589-594.

S. Kalinin, D. Bonnell, M Freitag, A. T. Johnson (2002) Tip-Gating Effect in Scanning Impedance Imaging of Nanoelectronic Devices. Appl. Phys. Lett. 81 5219-5221.

S. Kalinin, M. Freitag, A. T. Johnson, D. Bonnell. (2002) Carbon Nanotubes As A Tip Calibration Standard In Electrostatic Scanning Probe Microscopies. Appl. Phys. Lett. 81 754-756.

S. Kalinin, C. Johnson, D. A. Bonnell (2002) Domain Polarity and Temperature Induced Potential Inversion on the BaTiO3 (100) Surface 91 3816. Applied Physics Letters.

S. Kalinin, D. Bonnell, K.M. Nair, A.S. Bhalla, T.K. Gupta, et al. (2002) Dielectric Materials and Devices, Eds. Temperature-Dependent Polarization And Electric Potential On Ferroelectric BaTiO3 (100) Surface. Proceedings of 102 American Ceramic Society Meeting.

S. Kalinin, M. Sochumel, P. Davies, D. Bonnell J. (2002) Potential And Impedance Imaging Of Polycrystalline BiFeO3 Ceramics. Am. Ceram. Soc., 85 3011-3117.

G. Popov, S.V. Kalinin, T. Alvarez, T. Emge, M. Greenblatt, and D.A. Bonnell (2002) Micromagnetic And Magnetoresistance Studies Of Ferromagnetic La0.83Sr0.13MnO2.98 Crystals. Physical Review B, 64 064426.

J. R. Smith, D. A. Bonnell (2002) Nanometer Scale Property Variation in CrOCN Thin Films. J. American Ceramic Society 85 2873-81.


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Joseph Bordogna

lfred Fitler Moore Professor of Engineering
Email: bordogna at seas.upenn.edu
Personal Website

Research Interests:
Optoelectronics, manufacturing systems, environmental technologies, management of technological innovation, educational innovation, federal science and engineering policy.

Selected Recent Publications:
Bordogna, J. Time travel to 2029: Nanotechnology. Semiconductor International, v 27, n 1, Jan. 2004, p 40-2.

Bordogna, J. Nano transformations: a future of our making. IEEE International Electron Devices Meeting 2003, 2003, p 1.3.1-4.

Bordogna, Joseph. Eisenstein's departure from the NSF [3]. Science, v 297, n 5579, Jul 12, 2002, p 193-194.


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Gershon Buchsbaum

Professor of Bioengineering; Member of the Institute for Neurological Sciences; Member of the Institute for Medicine and Engineering; Member of the Institute for Research in the Cognitive Sciences
Email: gershon at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Visual signal processing and image coding, modeling of retinal and visual system architecture and function, auditory-visual scene analysis, computational neuroscience. Research Techniques: Modeling and simulation; image processing; digital signal processing; neural networks. Research Summary: The neural architecture of the visual system with its unique and elaborate response properties in space, time and color provides us with all the features and richness of our visual world. The main goals of our research are: 1) to understand how the visual neural architecture is matched to the image and how it samples, codes and processes the different features of the image. 2) To identify the attributes of natural images that are most critical for coding in the visual system. Questions we ask are: What are the significant correlations and functional relations among the different image features? How do critical parameters such as contrast in time, space and color and local and global details affect visual image processing? How does visual processing match and adapt to dynamic changes in the image? How does the visual system extract image features such as spatial detail and color? To investigate these questions, we apply quantitative analysis and simulation methods from image processing and neural networks that are rigorously based on known anatomy and physiology and explore the design principles and strategy underlying the visual system neural architecture.

Selected Recent Publications:
Buchsbaum, G., Bloch, O. Color categories revealed by non-negative matrix factorization of Munsell color spectra. Vision Research, v 42, n 5, March 2002, p 559-63.

D. Tailor, L. Finkel, G. Buchsbaum. Color Opponent Receptive Fields Derived from Independent Component Analysis of Natural Images. Vision Research, 40, 2671-2676, 2000.


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Jason A. Burdick

Assistant Professor of Bioengineering
Email: burdick2 at seas.upenn.edu
Personal Website

Research Interests:
Developing degradable polymeric biomaterials that can be used for tissue engineering, drug delivery, and fundamental polymer studies. The platform polymer technology involves the development of multifunctional monomers that form degradable crosslinked networks via a photoinitiated polymerization. Dr. Burdick’s specific research interests include: scaffolding for cell and growth factor delivery in bone and cartilage regeneration, molecule delivery for treatment of the injured spinal cord, and investigating the influence of monomer structure on resulting network macroscopic and microscopic properties.

Selected Recent Publications:
J.A. Burdick and Molly M. Stevens, “Biomedical Hydrogels,” in Biomaterials, Artificial Organs, and Tissue Engineering (eds. J. Jones and L. Hench), Woodhead Publishing Ltd., Cambridge, in press.

B.A. Pfeifer, J.A. Burdick, S. Little, R. Langer, “Poly(ester-anhydride):Poly(
-amino ester) Micro- and Nanospheres: DNA Encapsulation and Cellular Transfection,” International Journal of Pharmaceutics, in press.

J.A. Burdick, M. Ward, E. Liang, M.J. Young, R. Langer, “Stimulation of Neurite Outgrowth by Neurotrophins Delivered from Degradable Hydrogels,” Biomaterials, in press.

S. Levenberg*, J.A. Burdick*, T. Kraehenbuehl, R. Langer, “Neurotrophin Induced Differentiation of Human Embryonic Stem Cells on 3-Dimensional Polymeric Scaffolds,” Tissue Engineering, 11: 506-512, 2005. (*authors contributed equally)

J.A. Burdick, C. Chung, X. Jia, M.A. Randolph, R. Langer, “Controlled Degradation and Mechanical Behavior of Photopolymerized Hyaluronic Acid Networks,” Biomacromolecules, 6: 386-391, 2005.

B.A. Pfeifer, J.A. Burdick, R. Langer, “Formulation and Surface Modification of Poly(Ester-Anhydride) Micro- and Nanospheres,” Biomaterials, 26: 117-124, 2005.

T.M. Lovestead, J.A. Burdick, K.S. Anseth, C.N. Bowman, “Understanding Multivinyl Monomer Photopolymerization Kinetics through Modeling and GPC Investigation of Degradable Networks,” Polymer, 46: 6226-6234, 2005.

A. Khademhosseini, J. Yeh, S. Jon, G. Eng, K.Y. Suh, J.A. Burdick, R. Langer, “Molded PEG Microstructures for Capturing and Shear Protecting Cells Within Microfluidic Channels,” Lab On A Chip, 4: 425-430, 2004.

J.A. Burdick, A. Khademhosseini, R. Langer, “Fabrication of Gradient Hydrogels Using a Microfluidics/ Photopolymerization Process,” Langmuir, 20: 5153-5156, 2004.

J.A. Burdick, M. Ward, E. Liang, M. Young, R. Langer, “Controlled Delivery of Neurotrophic Factors from Photocrosslinkable and Degradable PEG Hydrogels,” J. Neurotrauma 21: 1311, 2004.

D.G. Anderson, J.A. Burdick, R. Langer, “Smart Biomaterials,” Science, 305: 1923-1924, 2004.

X. Jia, J.A. Burdick, J. Kobler, R.J. Clifton, J.J. Rosowski, S.M. Zeitels, R. Langer, “Synthesis and Characterization of In Situ Crosslinkable Hyaluronic Acid-Based Hydrogels with Potential Application for Vocal Fold Regeneration,” Macromolecules, 37: 3239-3248, 2004.

J.A. Burdick, T.S. Johnson, M.A. Randolph, M. Yaremchuk, R. Langer, “Neocartilage Formation in Photocrosslinked PEG/Polysaccharide Hydrogels,” Transactions of the 5th Combined Meeting of the Orthopaedic Research Societies of the USA, Canada, Japan, and Europe, October 2004.

J.A. Burdick, T. Lovestead, K.S. Anseth, “Kinetic Chain Lengths in Highly Crosslinked Networks Formed by the Photoinitiated Polymerization of Degradable Divinyl Monomers: A GPC Investigation,” Biomacromolecules, 4: 149-156, 2003.

K.A. Davis, J.A. Burdick, K.S. Anseth, “Photopolymerized Crosslinked Degradable Copolymer Networks for Tissue Engineering Applications,” Biomaterials, 24: 2485-2495, 2003.

J.A. Burdick, W.S. Dernell, D. Frankel, K.S. Anseth, “An Initial Investigation of Photocurable 3-Dimensional Lactic Acid Based Scaffolds in a Critical-Sized Cranial Defect,” Biomaterials, 24: 1613-1620, 2003.

A.K. Poshusta, J.A. Burdick, D.J. Mortisen, R.F. Padera, D. Ruehlman, M.J. Yaszemski, K.S. Anseth, “Histocompatibility of Photocrosslinked Polyanhydrides: A Novel In Situ Forming Orthopaedic Biomaterial,” Journal of Biomedical Materials Research, 64A: 62-69, 2003.


K.S. Anseth and J.A. Burdick. New Directions in Photopolymerizable Biomaterials, MRS Bulletin, 27:130-138, 2002.

J.A. Burdick and K.S. Anseth. Photoencapsulation of Osteoblasts in Injectable RGD-Modified PEG Hydrogels for Bone Tissue Engineering, Biomaterials, 23: 4315-4323, 2002.


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Thomas A.V. Cassel

Practice Professor of Mechanical Engineering and Applied Mechanics; Director, Engineering Entrepreneurship Program
Email: tcassel at seas.upenn.edu
Personal Website

Research Interests:
Engineering Entrepreneurship

Selected Recent Publications:
Thomas Cassel. Engineering Entrepreneurship at Penn. Proceedings of the 2003 American Society for Engineering Education Annual Conference & Exposition. 2003.


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Christopher S. Chen

Associate Professor of Bioengineering
Email: chrischen at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Micro- and Nanotechnology; Transduction of mechanical forces by cells; Relationship between cellular and multicellular structure and biological function; Angiogenesis; Cancer; and Stem cell biology. Dr. Chen's laboratory studies how the interactions between cells and their surrounding tissue microenvironment drives their behavior. His group develops novel microfabriaction and nanotechnology-based tools to manipulate and monitor these interactions in order to better understand how cells function in normal and disease contexts.

Selected Recent Publications:
Nelson, CM; Jean, RP; Tan, JL; Liu, WF; Sniadecki, NJ; Spector, AA; Chen, CS. Emergent patterns of growth controlled by multicellular form and mechanics. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 102 (33):
11594-11599 AUG 16 2005.

Herndon, T.M., Pirone, D.M., Tsokos, G.C., Chen, C.S., (2005) T cell-to-T cell clustering enhances NF-κB activitity by a PI3K signal mediated by Cbl-b and Rho. Biochem Biophys Res Comm. 332:1133-1139.

Tanase, M., Felton, E.J., Gray, D.S., Hultgren, A., Chen, C.S., Reich, D. (2005) Assembly of multicellular constructs and microarrays of cells using magnetic nanowires. Lab on a Chip. 5:598-605.

Lemmon, C.A., Sniadecki, N.J., Ruiz, S.A., Tan, J.T., Romer, L.H., Chen, C.S. (2005) Shear Force at the Cell-Matrix Interface: Enhanced Analysis For Microfabricated Post Array Detectors. Mechanics & Chemistry of Biosystems. 2(1):1-16.

Yim, E.K.F., Reano, R.M., Pang, S.W., Yee, A.F., Chen, C.S., Leong, K.W. (2005) Nanopattern-induced changes in morphology and motility in smooth muscle cells. Biomaterials. 26:54035-5413.

Chen, C.S., Jiang, X., Whitesides, G.M. (2005) Microengineering the Enviroment of Mammalian Cells in Culture. MRS Bulletin. 30:194-201.

Wang, A.Y., Mo, X., Chen, C.S., Yu, S.M., (2005) Facile Modification of Collagen Directed by Collagen Mimetic Peptides. J Am Chem Soc. 127(12):4130-4131

Hultgren, A., Tanase, M., Felton, E.J., Bhadriraju, K., Salem, A.K., Chen, C.S., Reich, D. (2005) Optimization of Yield in Magnetic Cell Separations Using Nickel Nanowires of Different Lengths. Biotech Prog. 21:509-515.

Pirone, D.M., Chen, C.S. (2004) Strategies for Engineering the Adhesive Microenviroment. (2004) J Mammary Gland Biol Neoplasia 9(4):405-417.

Pirone, D.M., Chen, C.S. (2004) Using lab-on-a-chip technologies to understand cellular mechanotransduction. Lab-On-Chips for Cellomics (ed. H. Anderson, A. van den Berg). Kluwer Academic. 16:1303-1313.

Raghavan, S., Chen, C.S. (2004) Micropatterned environments in cell biology. Adv Mat. 16:1303-1313.

Chen, C.S., Tan, J.L., Tien, J. (2004) Mechanotransduction at cell-matrix and cell-cell contacts. Ann Rev Biomed Eng. 6:275-302.

McBeath, R., Pirone, D., Nelson, C.M., Bhadriraju, K., Chen, C.S. (2004) Cell shape, cytoskeletal tension, and RhoA regulate stem cell lineage commitment. Development Cell. 6:483-495.

Nelson, C.M., Pirone, D., Tan, J.L., Chen, C.S. (2004) VE-cadherin regulates cytoskeletal tension, cell spreading and focal adhesions by stimulating RhoA. Mol Biol Cell. 15:2943-2953.

Gray, D.S., Tien, J., Chen, C.S. (2003) High conductivity elastomeric electronics. Advanced Materials. 166:393-397.

Birenbaum, N.S. , Lai, B.T., Chen, C.S. , Reich, D.H. and Meyer, G.J. (2003) Selective non-covalent adsorption of protein to bifunctional metallic nanowire surfaces. Langmuir. 19:9580-9582.

Tan, J.L., Liu, W., Nelson, C.M., Raghavan, S., Chen, C.S. (2003) A simple approach to micropattern cells on common culture substrates by tuning substrate wettability. Tissue Engineering. 10:865-872.

Chen, C.S ., Alonso, J.L., Ostuni, E., Whitesides, G.M., Ingber, D.E. (2003) Cell shape provides global control of focal adhesion assembly. Biochem Biophys Res Comm. 307:355-361.

Reich, D. H., M. Tanase, A. Hultgren, L. A. Bauer, Chen, C.S. , Meyer, G.J. (2003) Biological applications of multifunctional magnetic nanowires. J Appl Phys. 10:7275-7280.

Jean, R., Spector, A., Chen, C.S. (2004) Characterization of the nuclear deformation caused by changes in endothelial cell shape. J Biomech Eng. 126:552-558.

Gray, D.S., Chen, C.S. (2003) Patterning cells in registration with high fidelity using dielectrophoresis. Biosensors Bioelectronics. 19:771-780.

Nelson, C.M., Chen, C.S. (2003) Engineering cell adhesion for biotechnology applications. Chem Eng Tech.

Plant, A.L., Chen, C.S., Groves, J.T., Parikh, A.N. (2003) The biomolecular interface. Langmuir. 19:1449-1450.

Hultgren, A., Tanase, M., Chen, C.S ., Reich, D. (2003) Cell manipulation using magnetic nanowires. J Appl Phys. 10:7554-7556.

Tan, J.L., Tien, J., Pirone, D., Gray, D.S., Chen, C.S . (2003) Cells lying on a bed of microneedles: An approach to isolate mechanical force. Proc Nat Acad Sci USA. 100:1484-1489.

Nelson, C.M., Chen, C.S. (2003) VE-cadherin simultaneously stimulates and inhibits cell proliferation by altering cytoskeletal structure and tension. J Cell Science 116:3571-3581.

Nelson, C.M., Raghavan, S., Tan, J.L., Chen, C.S. (2002) Degradation of micropatterned surfaces by cell-dependent and -independent processes. Langmuir. 9:1493-1499.

Gray, D.S., Tien, J., Chen, C.S. (2002) Cell migration on surfaces patterned with differential mechanical compliance. J Biomed Mater Res. 66A(3):605-14.

Bhadriraju, K., Chen, C.S. (2002) Engineering cellular microenvironments to improve cell-based drug testing. Drug Disc Tod. 7:612-620.

Nelson, C.M., Chen, C.S. (2002) signaling by direct contact increases cell proliferation via a PI3K-dependent signal. FEBS Letters. 514:238-242.

Tan, J.L., Tien, J., Chen, C.S. (2002) Microcontact printing of proteins on mixed self-assembled monolayers. Langmuir. 18: 519-523.

Tien, J., Nelson, C.M., Chen, C.S. (2002) Fabrication of aligned microstructures with a single elastomeric stamp. Proc Nat Acad Sci USA. 99: 1758-1762.


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I-Wei Chen

Professor of Materials Science and Engineering
Email: iweichen at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Ferroelectric Oxides: Ferroelectrics are used in applications from smart skis to smart card, and in wireless communication gears. Their thin film and bulk properties are affected by internal and external interfaces, lattice defects, and electronic carriers, in addition to the underlying driving force and phase assemblage. Manipulating and understanding these relationships through processing and modeling is a focus of our research. cStructural Ceramics: We have developed two novel structural ceramics in recent years. One is a new tough Si-Al-O-N ceramic that can be used as a high temperature hard material such as metal cutting tools and engine parts. The other is a ceramic wood with a wavy multilayer texture that deflects cracks and allows graceful failure. Microstructure control is the key to these developments and a focus of our research. Nanocomposites: Nanophase materials often have physical, chemical and biological properties fit for new applications. We have developed a nanocomposite of silica and biomolecules that have excellent sensing and catalyzing capabilities. We also discovered some nanophase oxides that allow grain boundary diffusion but not grain boundary migration. Low temperature processing is the key to fabricating these nanocomposites and a focus of our research.

Selected Recent Publications:
Kim, C.J., and Chen. I.W. Resistance switching of Al/(Pr,Ca)MnO3 thin films. Japanese Journal of Applied Physics Part 2, 2005.

Kim, C.J., Kim, B.I., and Chen, I. Dependence of electrode on switching effect of Pr1-xCa xMnO3 thin film. Japanese Journal of Applied Physics Part 1, 2005.

McGill, S.A., Miller, R.I., Torrens, O.N., et al. Optical evidence for transient photoinduced magnetization in La0.7Ca0.3MnO3. Physical Review, 2005.

Stachelek, S.J., Alferieve, I., Choi, H., Kronsteiner, A., Uttayarat, P., Gooch, K.J., Composto, R.J., Chen, I., Hebbel, R.P., and Levy, R. J. Cholesterol-derivatized polyurethane: Characterization and endothelial cell adhesion. Journal of Biomedical Materials Research, 2005.

Chen, I., Lin, Y., and Lin, Y. Tunnel minimization and relay for managing virtual private networks. GLOBECOM-IEEE Global Telecommunications Conference, 2004.

Hazuda D.J., Anthony N.J., et al. A naphthyridine carboxamide provides evidence for discordant resistance between mechanistically identical inhibitors of HIV-1 integrase. Proceedings of the National Academy of Sciences of the United States of America, 2004.

Chen, I-wei, Mamchik, Alexander. Preparation of magnetically and electrically-induced variable resistance materials. U.S. Pat. Appl. Publ. 2004.

X.M. Chen, Y.H. Tang, I.-W. Chen, Z.C. Xu, S.Y. Wu. Dielectric and Magnetoelectric Characterization of CoFe2O4/Sr0.5Ba0.5Nb2O6 Composites. Submitted to J. Appl. Phys., 2004.

H. Choi, S. R. Choi, R. Zhou, H. F. Kung, I-W. Chen. Iron Oxide Nanoparticles as MR Contrast Agent for Tumor Imaging via Folate Receptor-targeted Delivery. Accepted for publication in Acad. Radiology, 2004.

Ilia Fishbein, Ivan S. Alferiev, John M. Vohs, Gordon S. Wong, I-Wei Chen, Alexander Mamchik, Robert J. Levy. Nanoscale Patterning of Adenoviral Gene Vectors on Steel Surfaces using Polybisphosphonates. Submitted to Nature Materials, 2004.

C-J. Kim, J. E. Sanchez, Jr., S. Longcor, and I-W. Chen. Resistance Switching at the Electrode Interface of (Pr,Ca)MnO3 Thin Films. Submitted to Appl. Phys. Lett., 2004.

Anna Marie Lipski, Claude Jaquiery, Hoon Choi, Daniel Eberli, Molly Stevens, Ivan Martin, I-Wei Chen, V. Prasad Shastri,. Nano-scale Engineering of Biomaterial Surfaces. Submitted to Nature Materials, 2004.

A.Mamchik, W. Dmowski, T. Egami, and I-Wei Chen. Magnetic Impurities in Conducting Oxides: II. (Sr1-xLax)(Ru1-xCox)O3 System. Submitted to Phys. Rev. B, 2004.

S.A. McGill, R.I. Miller, O.N. Torrens, A. Mamchik, I-Wei Chen and J.M. Kikkawa, Dynamic Kerr Effects and Spectral Weight Transfer in the Manganites. Accepted for publication in Phys. Rev. Lett., 2004.

S.A. McGill, R.I. Miller, O.N. Torrens, A. Mamchik, I-Wei Chen and J.M. Kikkawa. Optical Evidence for Transient Photo-induced Magnetization in La0.7Ca0.3MnO3. submitted to Phys. Rev. Lett, 2004.

Shastri, Venkatram P., Chen, I-Wei, Choi, Hoon, Lipski, Anna Marie.Engineering of material surfaces with functional particles. U.S. Pat. Appl.Publ. 2004, 22 pp., Cont.-in-part of U.S. Ser. No. 427,242.

V. P. Shastri, I-Wei Chen and William Znidarsic. Biomimetic Hierarchies usingFunctionalized Nanoparticles as Building Blocks. U.S. Patent application, 2004.

Sy, Jay C., Chen, I-Wei, Shastri, V. Prasad. Emulsion-based control ofelectrospun fiber morphology. Polymer Preprints (American Chemical Society,Division of Polymer Chemistry) 2004.

Yu, Jay, Du, Henry, Shuba, Roman, Chen, I-Wei. Dopant-dependent oxidationbehavior of a-SiAlON ceramics. Journal of Materials Science, 2004.

Zenotchkine, M., Shuba, R., Chen, I-Wei. Liquid-phase growth of small crystalsfor seeding a-SiAlON ceramics. Journal of the American Ceramic Society, 2004.

I-Wei Chen and A. Mamchik. Magnetically and Electrically-Induced Variable Resistance Materials and Method for Preparing Same. U.S. Patent application, 2003.

Chen, I. -Wei, Shuba, R. A., Zenotchkine, M. Y. Development of tough a-Sialon. Key Engineering Materials, 2003.

I.-W. Chen, L. Wang and A. Davenport. Accelerated Precipitate Coarsening due to a Concomitant Secondary Phase Transformation. Acta Materialia, 51 [6] 1691 - 1703, 2003.

H. Choi and I-Wei Chen. Fibrous Composites for Tissue Engineering. U.S. Patent application, 2003.

H. Choi and I-Wei Chen. Nanometer-sized Carrier Medium. U.S. Patent application, 2003.

H. Choi and I-W. Chen. Surface-modified Silica Colloid for Diagnostic Imaging. J. Colloid Interf. Sci., 282 [2], 435-37, 2003.

A. Mamchik and I-W. Chen. Large Magnetoresistance in Magnetically Frustrated Ruthenates. Appl. Phys. Lett. 82 [4] 613-15, 2003.

A. Mamchik and I-Wei Chen. Magnetic Impurities in Conducting Oxides: I. (Sr1-xLax)(Ru1-xFex)O3 System. Submitted to Phys. Rev. B, 2003.

V. P. Shastri, I-Wei Chen, H. Choi and A. M. Lipski. Functionalized Surface Coatings for Biomedical Uses. U.S. Patent application, 2003.

Stanley J. Stachelek, Ivan Alferiev, Hoon Choi, Allyson Kronsteiner, Pimporn Uttayarat, Keith Gooch, Russ Composto, I-Wei Chen, Robert J. Levy. Cholesterol Derivatized Polyurethane: Characterization and Endothelial Cell Adhesion. Submitted to J. Biomaterials, 2003.

Wang, Lingling, Tien, Tseng-Ying, Chen, I-Wei. Formation of b-silicon nitridecrystals from (Si,Al,Mg,Y)(O,N) liquid: II, population dynamics and coarseningkinetics. Journal of the American Ceramic Society, 2003.

Wang, Lingling, Tien, Tseng-Ying, Chen, I-Wei. Formation of b-silicon nitridecrystals from (Si,Al,Mg,Y)(O,N) liquid: I, phase, composition, and shapeevolutions. Journal of the American Ceramic Society, 2003.

Zenotchkine, M., Shuba, R., Chen, I-Wei. Effect of seeding on themicrostructure and mechanical properties of a-SiAlON: III, comparison ofmodifying cations. Journal of the American Ceramic Society, 2003.

Chen, I-Wei. Antiferroelectricity-the invisible hand behind goodferroelectrics. Dielectric Materials and Devices, [Proceedings of theAdvances in Dielectric Materials and Multilayer Electronic Devices Symposium atthe 102nd Annual Meeting of the American Ceramic Society], St. Louis, MO,United States, Apr. 30-May. 3, Meeting Date 2000, 519-531, 2002.

Dakskobler, Ales, Kosmac, Tomaz, Chen, I-Wei. Paraffin-based process forproducing layered composites with cellular microstructures. Journal of the American Ceramic Society, 2002.

Riedel, Ralf, Zerr, Andreas, Schwarz, Marcus Rolf, Kroke, Edwin Rolf Balduin,Chen, I-wei. Sialon spinel and multicomponent (oxide)-nitride-spinels, amethod for their production, and their use. PCT Int. Appl, 2002.

Schwarz, Marcus, Zerr, Andreas, Kroke, Edwin, Miehe, Gerhard, Chen, I-Wei,Heck, Martin, Thybusch, Brunhilde, Poe, Brent T., Riedel, Ralf. Spinelsialons. Angewandte Chemie, International Edition, 2002.

Zenotchkine, Misha, Shuba, Roman, Chen, I-Wei. Effect of heating schedule onthe microstructure and fracture toughness of a-Sialon-cause and solution.Journal of the American Ceramic Society, 2002.

M. Zenotchkine, R. Shuba, and I-W. Chen. Effect of Seeding on the Microstructure and Mechanical Properties of -SiAlON: II. Ca-SiAlON. J. Am. Ceram. Soc., 85 [5] 1260-67, 2002.

Zenotchkine, Misha, Shuba, Roman, Kim, Joo-Sun, Chen, I-Wei. Effect of seeding on the microstructure and mechanical properties of a-SiAlON: I, Y-SiAlON. Journal of the American Ceramic Society, 2002.


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Ira M. Cohen

Professor of Mechanical Engineering and Applied Mechanics
Email: imcohen at seas.upenn.edu
Personal Website

Research Interests:
When a gas is sufficiently ionized that the Debye length is the smallest characteristic length, we may call it plasma. Plasmas are used for illumination as glow and arc discharges, for melting and welding materials, and for etching, deposition, and spray coating. We have studied the heating, melting, rollup into a ball, cooling and solidification of very fine wires used for microelectronic interconnections. The heat is supplied by a low current electric arc discharge struck between the wire anode and a cathode. We are also interested in plasmas that occur in combustion flames as well as high intensity plasmas used for spray deposition to create temperature or corrosion resistant coatings. Finally, breakdown characteristics of gases may be used in diagnostics of gas composition.

The classical problem of the decay of a laminar shear layer, starting from a velocity discontinuity at the origin, has never been solved. A basic question related to the solution of this problem is the following. The Navier-Stokes equations which describe the problem are elliptic. Why is it that the Navier-Stokes equations require downstream boundary conditions on the velocity components for an unique solution, but the boundary layer equations, which are purported to be the downstream limit of the Navier-Stokes equations, being parabolic, cannot accept a downstream boundary condition?

Selected Recent Publications:

Ira M. Cohen and Pijush K. Kundu. Fluid Mechanics,Third Edition. Elsevier Academic Press, 2004.

S. S. Sripada, Ira M. Cohen and P. S. Ayyaswamy. Melting of a wire anode followed by solidification: A three-phase moving interface problem. Trans. ASME, J. Heat Transfer, 125, pp. 661 - 668, 2003.

Ira M. Cohen and P. S. Ayyaswamy. Low energy plasma heat transfer as applied to microelectronic manufacturing. Annual Review of Heat Transfer, Vol. XII, edited by C. L. Tsien, V. Prasad, and F. Incropera, pp. 27 -78, Begell House, Inc., New York, 2002.


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Russell J. Composto

Graduate Chair of Materials Science and Engineering; Associate Professor of Materials Science and Engineering; Associate Professor of Chemical and Biomolecular Engineering
Email: composto at lrsm.upenn.edu
Personal Website   |   Research Website

Research Interests:
Polymeric coatings are important in the microelectronics, medical, and chemical industries. Whereas many formulations rely on Edisonian principles, our research aims to provide a fundamental understanding of surface and interface properties using a tool-box of complimentary techniques including low-energy forward recoil spectrometry, a technique developed at Penn, neutron reflectivity, atomic force microscopy, and self-consistent mean field models (SCMF). This research provides new opportunities for technologists to optimize material properties by manipulating macromolecules. Molecular Control of Adhesion: Block copolymers designed to have one block anchor to a substrate and the other entangle with matrix chains can greatly improve adhesion. Previous studies have focused on varying matrix chain length and type in order to manipulate interfacial properties such as interfacial excess and adsorbed layer thickness. Using SCMF, the segment-substrate interaction strength can be determined. Future studies will involve variation of block lengths and substrate surface energy, and adhesion. Dynamics of Phase Separating Thin Film Blends: Many industrial coatings involve multi-phase systems. We are studying how films undergoing phase separation are influenced by surface and interface wetting. A comprehensive understanding of thin film kinetics is underway by simultaneously measuring the wetting layer growth, phase morphology below the wetting layer, domain coarsening, and surface roughness. By understanding how phase separation influences wetting, technologists will be able to control film properties including wettability, wear and permeability.

Selected Recent Publications:
Costa, AC; Composto, RJ; Vlcek, P; Morera, S. Dewetting and adsorption in homopolymer films containing triblock copolymers: Role of chain architecture and anchoring block molar fraction. JOURNAL OF ADHESION, 81 (7-8): 683-698 JUL-AUG 2005.

Walters, R.M., Winey, K.I., Composto, R.J. Kinetics of surface segregation in ionomer films. Polymer, submitted.

Characterization of Dextran Coatings on Silicon Wafers: a Model Surface for studying gas bubbles adhesion to vessel walls in intravascular gas embolism. M. Ombelli, D. M. Eckmann† and R. J. Composto, J. Langmuir, submitted.

A.C. Costa, M Geoghegan, P. Vlcek and R. J. Composto. Block Copolymer Adsorption from a Homopolymer Melt to Silicon Oxide: Effects of Non-Adsorbing Block Length and Anchoring Block-Substrate Interaction. Macromolecules, in press.

A. R. El-Ghannam, P. Ducheyne C. S. Adams, R. J. Composto, I. M. Shapiro, and. J. Bio. Model Surfaces engineered with nanoscale roughenss and RGD tripeptides promote osteoblast activity Mat. Res., in press.

G.K. Toworfe, R.J. Composto, I.M. Shapiro, P. Ducheyne, Nucleation and growth of calcium phosphate on amine-, carboxyl- and hydroxyl-silane self assembled monolayers, Biomaterials. 2005 Aug 1.

Uttayarat P, Toworfe GK, Dietrich F, Lelkes PI, Composto RJ. Topographic guidance of endothelial cells on silicone surfaces with micro- to nanogrooves: Orientation of actin filaments and focal adhesions. J Biomed Mater Res A. 2005 Aug 18.

Uttayarat, P., Lelkers, P.I., and Composto, R.J. Effect of nano-to micro-scale surface topography on the orientation of endothelial cells. Materials Research Society Symposium Proceedings, Nanoscale Materials Science in Biology and Medicine, 2005.

Ombelli, M., Costello, L.B., Meng, Q.C., Composto, R.J., and Eckmann, D. Competitive adsorption of plasma proteins on polysaccharide-modified silicon surfaces. Materials Research Society Symposium Proceedings, Nanoscale Materials in Biology and Medicine, 2005.

Grigoriou, V., Shapiro, I. Cavalcanti-A., Elisabeth, A., Composto, R.J. et al. Apoptosis and survival of osteoblast-like cells are regulated by surface attachment. Journal of Biological Chemistry, 2005.

Stachelek, S.J., Alferiev, I., Choi, H., Kronsteiner, A., Uttayarat, P., Gooch, K.J., Composto, R.J., et al. Cholesterol-derivatized polyurethane: Characterization and endothelial cell adhesion. Journal of Biomedical Materials Research, 2005.

Lee, M.H., Brass, D.A., Morris, R., Composto, R.J., Ducheyne, P. The effect of non-specific interaction on cellular adhesion using model surfaces. Biomaterials, 2005.

Ombelli, M., Costello, L., Meng, Q.C., Composto R.J. Quantitative evaluation of proteins adsorbed on polysaccharide biomimetic coatings. JOM, 2004.

G. K. Toworfe, R. J. Composto, C. S. Adams, I. M. Shapiro, P. Ducheyne. Fibronectin adsorption on surface-activated polydimethylsiloxane and its effect on cellular function. Journal of Biomedical Materials Research, 2004.

H. J. Chung and R. J. Composto. Breakdown of Dynamic Scaling in Thin Film Polymer Blends Undergoing Phase Separation. Phys. Rev. Lett., 92, 185704, 2004.

A. C. Costa and R. J. Composto, C. Creton, P. Vlcek, and A. Chiche. Tack Tests of Block Copolymer-Homopolymer Adhesion Polymer, 45, 4445-4451, 2004.

M. H. Lee, R. M. Morris, D. Boettiger, R. J. Composto, P. Ducheyne Quantitative Measurements of Protein Adsorption and Fibronectin-mediated Cell Adhesion on Self-Assembled Monolayer Substrates. 2004 World Biomaterials Congress, Australia, April 2004.

D. Miksa, E. Irish, D. Chen, R. J. Composto and D. M. Eckmann. Biomimetic surfaces via dextran immobilization; characterization and analysis. Spring MRS Meeting, San Francisco. April 2004.

G. Toworfe, R. J. Composto, C. S. Adams, I. M. Shapiro, P. Ducheyne. Effect of Surface Activated Polydimethyl-Siloxane on Fibronectin Adsorption and Cell Function.Mat. Res. Soc. Symp. Proc. Vol. EXS-1, Materials Research Society: Pittsburg, PA F7.8.1, 2004.

R. J. Composto and H-J. Chung. Phase Separation Dynamics in Thin-Film Polymer Blends: Influence of Polymer Composition and Mobile Nanoparticles. Poly. Mat. Sci. and Engineering 89, 117, 2003

A. C. Costa, R. J. Composto and P. Vlcek. Dewetting of Thin Film Blends Containing Block Copolymer: Effects of Nonadsorbing Block Length and Substrate Hydrophobicity. Macromolecules, 36, 3254-3260, 2003.

M. Ombelli, D. M. Eckmann and R. J. Composto. Biomimetic Dextran Coatings On Silicon Wafers: Thin Film Properties And Wetting. Mat. Res. Soc. Symp. Proc. Vol. 734, Materials Research Society: Pittsburg, PA, B10.7.1, 2003.

M. Ombelli, D. M. Eckmann and R. J. Composto. Dextran Grafted Silicon Substrates: Preparation, Characterization And Biomedical Applications. Mat. Res. Soc. Symp. Proc. Vol. 774, Materials Research Society: Pittsburg, PA, O7.25.1, 2003.

H. Wang and R. J. Composto. Wetting and Phase Separation in Polymer Blend Films: Identification of Four Thickness Regimes with Distinct Morphological Pathways. Special Issue: Polymers at Interfaces. Interface Science, 11, 237-248, 2003

H. Wang, J. F. Douglas, S. K. Satija, R. J. Composto, and C. C. Han. Early-Stage Compositional Segregation in Polymer Blend Films. Physical Review E, 67, 061801, 2003.

E. A. Calvalcanti-Adam, I. M. Shapiro, E. J. Macarak, R. J. Composto, A. El Ghannam, C. S. Adams. RGD Peptides Immobilized on a mechanically deformable surface promote osteoblast differentiation. J. Bone Min. Res., 17, 2130-2140, 2002.

R. J. Composto, R. Walters and J. Genzer. Ion Beam Techniques and Their Application in Polymer Science. Materials Science and Engineering Reports: A Review Journal. Elsevier Science, Switzerland. (38/3-4 pp. 107-180) 1 July 2002

R. M. Walters, K. E. Sohn, K. I. Winey, and R. J. Composto. Local Acid Environment in Poly(ethylene-ran-methacrylic acid) Ionomers. J. Poly. Sci.: Physics, 41, 2833-2841, 2002.

H. Wang and R. J. Composto. Kinetics of Surface and Interfacial Fluctuations in Phase Separating Polymer Blend Films. Macromolecules, 35, 2799-2809, 2002.


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John C. Crocker

Assistant Professor of Chemical and Biomolecular Engineering and Skirkanich Assistant Professor of Innovation in Chemical Engineering
Email: jcrocker at seas.upenn.edu
Personal Website

Research Interests:
Microrheology of biopolymers, recA searching, 3-D microscopy, device biophysics. Dr. Crocker's research seeks to understand the feedback of mechanical force or stress with biochemistry on the cellular and macromolecular scales and to use the results to engineer useful devices for medical and biochemical applications.

Selected Recent Publications:
M.P. Valignat, O. Theodoly, J.C. Crocker, et al. Reversible self-assembly and directed assembly of DNA-linked micrometer-sized colloids. Proceedings of the National Academy of Sciences of the United States of America, 102(12):4225-9 March 22 2005.

P. L. Biancaniello, A.J. Kim, and J.C. Crocker. Colloidal interactions and self-assembly using DNA hybridization. Physical Review Letters, v 94, n 5, February 11 2005, p 1-4.

A.J. Kim, V. N. Manoharan, J.C. Crocker. Swelling-based method for preparing stable, functionalized polymer colloids. Journal of the American Chemical Society, v 127, n 6, Feb 16 2005, p 1592-1593.

J.C. Crocker, B.D. Hoffman, G. Massiera, et al. Rheology and strain fluctuations in living cells: Implications for cell mechanics. Biophysical Journal 86(1): 59A-59A Part 2 Suppl. S Jan 2004.

D.T. Chen, E.R. Weeks, J.C. Crocker, M.F. Islam, R. Verma, J. Gruber, A.J. Levine, T.C. Lubensky and A.G. Yodh. Rheological Microscopy: Local mechanical properties from microrheology. Phys. Rev. Lett., 90 (10): 108301, 2003.

Milam, Valeria T., Hiddessen, Amy L., Crocker, John C., Graves, David J., Hammer, Daniel A. DNA-Driven Assembly of Bidisperse, Micron-Sized Colloids. Langmuir, v 19, n 24, Nov 25, 2003, p 10317-10323.

Crocker, John C., Kim, Anthony J., Biancaniello, Paul. Programming colloidal interactions with DNA hybridization. Abstracts of Papers, 226th ACS National Meeting, New York, NY, United States, September 7-11, 2003.

M.L. Gardel, M.T. Valentine, J.C. Crocker, A.R. Bausch and D.A. Weitz. Microrheology of Entangled F-actin Solutions. Phys. Rev. Lett., 91 (15): 158302, 2003.

A.W.C. Lau, B.D. Hoffman, A. Davies, J.C. Crocker and T.C. Lubensky. Microrheology, stress fluctuations, and active behavior of living cells. Phys. Rev. Lett., 91 (19): 198101, 2003.

Dasgupta, B.R., Shang-You Tee, Crocker, J.C., Frisken, B.J., Weitz, D.A. Microrheology of polyethylene oxide using diffusing wave spectroscopy and single scattering. Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), v 65, n 5, p 051505/1-10 May 2002.


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Kostas Daniilidis

Associate Professor of Computer and Information Science
Email: kostas at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
Omnidirectional Vision, Tele-immersion, Analysis of Visual Motion.

Selected Recent Publications:

Yu, W., Sommer, G., Daniilidis, K. Duncan, J.S. Using skew Gabor filter in source signal separation and local spectral orientation analysis. Image and Vision Computing, 2005.

Gupta, D., Kumar, A., Daniilidis, K. Using omnidirectional structure from motion for registration of range images or minimal overlap. Proceedings – 2nd International Symposium on 3D Data Processing, Visualization and Transmission, 2004.

Zabulis, X., and Daniilidis, K. Multi-camera reconstruction based on surface normal estimation and best viewpoint selection. Proceedings – 2nd International Symposium on 3D Data Processing, Visualization and Transmission, 2004.

Isler, V., Kannan, S., Daniilidis, K. Sampling based sensor-network deployment. IEEE/RSJ International Conference on Intelligent Robots and Systems, 2004.

Daniilidis, K., and Papanikolopoulos, N. Special issue on panoramic robots. IEEE Robotics and Automation Magazine, 2004.

Gupta, D. and Daniilidis, K. Planar motion of a parabolic catadioptric camera. Proceedings – International Conference on Pattern Recognition, 2004.

Makadia, A., Sorgi, L., and Daniilidis K. Rotation estimation from spherical images. Proceedings – International Conference on Pattern Recognition, 2004.

Naroditsky, O. and Daniilidis, K. 3D scanning using spatiotemporal orientation. Proceedings – International Conference on Pattern Recognition, 2004.

Sorgi, L. and Daniilidis, K. Template gradient matching in spherical images. Proceedings of SPIE – The International Society for Optical Engineering, Imaging Processing: Algorithms and Systems III, 2004.

V. Isler, S. Kannan, K. Daniilidis, P. Valtr. VC-Dimension of Exterior Visibility, IEEE Trans. Pattern Anal. Mach. Intell., 2004.

Mulligan, J., Zabulis, X., Kelshikar, N., and Daniilidis, K. Stereo-based environment scanning for immersive telepresence. IEEE Transactions on Circuits and Systems for Video Technology, 2004.

A. Ansar and K. Daniilidis, Linear Pose Estimation from Points and Lines, IEEE Trans. Pattern Anal. Mach. Intell., 25:578-589, 2003.

C. Geyer and K. Daniilidis. Mirrors in motion: Epipolar geometry and motion estimation. International Conference on Computer Vision, Nice, France, pp. 766-773, 2003.

C. Geyer and K. Daniilidis. Omnidirectional Video. The Visual Computer, accepted, 2003.

A. Makadia and K. Daniilidis. Direct 3D-rotation estimation from spherical images via a generalized shift theorem. IEEE Computer Vision Pattern Recognition, 2003.

V. Isler, S. Kannan, and K.Daniilidis. Local Exploration Algorithms: Competitive Analysis and Probabilistic Framework. In Proc. IEEE Int. Conf. on Robotics and Automation, Taipei, Taiwan. May 12-17, 2003.

J. Mulligan and N. Kelshikar and X. Zabulis amd and K. Daniilidis. Stereo-based environment scanning for immersive tele-presence, IEEE Trans. on Circuits and Systems for Video Technology, Special Issue on Immersive Telepresence, 2003, accepted.

W. Yu and G. Sommer and K. Daniilidis. 3D-Orientation Signatures with Conic Kernel Filtering for Multiple Motion Analysis. Image and Vision Computing, 2003.

A. Ansar and K. Daniilidis. Linear Pose Estimation from Points or Lines. In Proc. Seventh European Conference on Computer Vision, Copenhagen, Denmark, 2002.

K. Daniilidis. Oriented Structure of the Occlusion Distortion: Is It Reliable? IEEE Trans. Pattern Anal. Mach. Intell., 24:1286-1290, 2002.

K. Daniilidis, C. Geyer, V. Isler, and A. Makadia. Omnidirectional Sensing for Robot Control. In Workshop on Control Problems in Robotics and Automation, Dec 2002.

C. Geyer and K. Daniilidis. Para-cata-dioptric Calibration. IEEE Trans. Pattern Anal. Mach. Intell., 24:687--695, 2002.

C. Geyer and K. Daniilidis. Properties of the Catadioptric Fundamental Matrix. In Proc. Seventh European Conference on Computer Vision, Copenhagen, Denmark, 2002.

J. Mulligan, V. Isler, K. Daniilidis. Trinocular Stereo: A New Algorithm and its Evaluation. International Journal for Computer Vision, Special Issue on Stereo and Multi-baseline Vision, 47:51-61, 2002.

H.~Towles, W.-C. Chen, R.~Yang, S.-U. Kum, H.~Fuchs, N.~Kelshikar, J.~Mulligan, K.~Daniilidis, L.~Bolden, B.~Zelesnik, A.~Sadagic, and J.~Lanier. 3D Tele-collaboration over Internet2. In International Workshop on Immersive Telepresence, Juan-les-Pins, France, Dec 2002.

W. Yu, G. Sommer, and K. Daniilidis. Multiple Motion Analysis: in Spatial Domain or in Spectral Domain? Computer Vision and Image Understanding, 2002.


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Susan B. Davidson

Appointments: Weiss Professor of Computer and Information Science; Deputy Dean of the School of Engineering and Applied Science
Email: susan at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
Distributed systems, database systems, and bioinformatics.

Selected Recent Publications:
Steven Bird, Yi Chen, Susan Davidson, Haejoong Lee, Yifeng Zheng. Extending XPath to Support Linguistic Queries. Programming Language Technologies for XML, 2005.

Yi Chen, Susan Davidson, Yifeng Zheng. ViteX: a Streaming XPath Processing System. International Conference on Data Engineering, 2005.

Yi Chen, Susan Davidson, Yifeng Zheng. BLAS: An Efficient XPath Processing System. SIGMOD, 2004.

Yi Chen, George A. Mihaila, Susan Davidson, Sriram Padmanabhan. EXPedite: a system for Encoded XML Processing. Thirteenth Conference on Information and Knowledge Management, 2004.

Vanessa Braganholo, Susan Davidson, Carlos Heuser. From XML View Updates to Relational View Updates: old solutions to a new problem. International Conference on Very Large Databases (VLDB), 2004.

Vanessa Braganholo, Susan Davidson, Carlos Heuser. Propagating XML View Updates to a Relational Database. Technical Report RP-341, 2004.

Yi Chen, Susan Davidson, Yifeng Zheng. BLAS: An Efficient XPath Processing System. SIGMOD2004, 2004.

Vanessa Braganholo, Susan Davidson, Carlos Heuser. On the updatability of XML views over relational databases. WebDB 2003, 2003.

Vanessa Braganholo, Susan Davidson, Carlos Heuser. Reasoning about the updatability of XML views over relational databases. Technical Report MS-CIS-03-13, 2003.

Vanessa Braganholo, Susan Davidson, Carlos Heuser. UXQuery: building updatable XML views over relational databases. Proceedings of the Brazilian Symposium on Databases, 2003.

Vanessa Braganholo, Susan Davidson, Carlos Heuser. Using XQuery to build updatable XML views over relational databases.Technical Report MS-CIS-03-18, 2003.

Peter Buneman, Susan Davidson, Wenfei Fan, Carmem Hara, Wang-Chiew Tan. Reasoning about Keys for XML. Information System, 2003.

Yi Chen, Susan Davidson, Carmem Hara, Yifeng Zheng. RRXS: Redundancy reducing XML storage in relations. International Conference on Very Large Databases (VLDB), 2003.

Susan Davidson, Wenfei Fan, Carmem Hara, Jing Qin. Propagating XML Constraints to Relations. ICDE2003, 2003.

Yi Chen, Susan Davidson, Yifeng Zheng. Constraint Preserving XML Storage in Relations. WebDB, 2002.

Yi Chen, Susan Davidson, Yifeng Zheng. Validating Constraints in XML. Technical Report MS-CIS-02-03, 2002.

Yi Chen, Susan Davidson, Yifeng Zheng. XKvalidator: A Constraint Validator For XML. Proceedings of ACM Conference on Information and Knowledge, 2002.


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Peter K. Davies

Chairman and Professor of Materials Science and Engineering
Email: davies at lrsm.upenn.edu
Personal Website

Research Interests:
Ceramics for Wireless Communication: Ceramic dielectric resonators have revolutionized microwave-based wireless communication devices by reducing the size and cost of filters and oscillators in systems ranging from cellular phones to global positioning technologies. The goals of our work are to understand what aspects of the chemistry, structure and processing of these materials are critical in realizing an optimized electronic performance, and use these crystal chemical insights to design and prepare new oxides with an improved dielectric performance. Relaxor Ferroelectric Oxides: Relaxor ferroelectric oxides such as lead magnesium niobate have attracted widespread interest for applications in multi-layer capacitors, transducers, electro-optic devices, and thin film memories. The properties of these systems are intimately related to the nano-level ordering of the metal cations in their crystal structures. Using a broad range of probes to explore their local structure, and new processing schemes and chemical substitutents, we have developed methods to control the cation order and modify the ferroelectric properties of these systems. These approaches are being used to develop a new class of ferroelectric and piezoelectric materials. Cation Order in Electronic Oxides: Ordering reactions can be responsible for order of magnitude changes in the conduction, dielectric, and optical properties of oxide systems. We are using a combination of TEM and diffraction probes, and novel low temperature synthesis routes to explore the response of the properties of a series of transition metal oxide systems to variations in their short-, medium-, and long-range cation order.

Selected Recent Publications:
Magid, R; Davies, PF. Endothelial protein kinase C isoform identity and differential activity of PKC xi in an athero-susceptible region of porcine aorta. CIRCULATION RESEARCH, 97 (5): 443-449 SEP 2 2005.

M.R. Suchomel, and P.K. Davies. Enhanced tetragonality in x(PbTiO/sub 3/-(1-x)Bi(Zn/sub 1/2 /Ti/sub1/2/)O/sub 3/ and related solid solution systems. Applied Physics Letters, v 86, n 26, June 27, 2005, p 262905-1-3.

M. Thirumal and P.K. Davies. Ba8ZnTa6O24: A New High Q Dielectric Perovskite. Journal of the American Ceramic Society, (in press)

M. Thirumal and P. K. Davies. Tunable High Q Perovskite Dielectrics in the BaO-NiO-Ta2O5 System. Applied. Physics Letters, under review.

A.Y. Borisevich and P.K. Davies. Effect of V2O5 doping on the sintering and dielectric properties of M-phase Li1+x-yNb1-x-3yTix+4yO3 ceramics. Journal of the American Ceramic Society, 2004.

P. Juhas, M. Akbas and P.K. Davies. Structure and Dielectric Properties of the Pb(Sc2/3W1/3)O3-PbMO3 Relaxors (M=Zr, Ti). Journal of the American Ceramic Society. 2004.

P. Juhas, I. Grinberg, A.M. Rappe, W. Dmowski, T. Egami, and P.K. Davies. Correlations Between the Structure and Dielectric Properties of Pb(Sc2/3W1/3)O3-Pb(Ti/Zr)O3 Relaxors. Physical Review B, 2004.

M.R. Suchomel and P.K. Davies. Predicting the Position of the Morphotropic boundary in New High Temperature PbTiO3-Bi(B'B") O3 Based dielectric Ceramics. Journal of Applied Physics, 2004.

H. Wu and P.K. Davies. Non-stoichiometric 1:2 Ordered Perovskites in the Ba(Li1/4Nb3/4)O3-Ba(Li2/5W3/5)O3 System. Journal of Solid State Chemistry, 2004.

H. Wu and P.K. Davies. Ordered Perovskites in the A2+(Li1/4Nb3/4)O3-A2+(Li2/5W3/5)O3 (A2+ = Sr ,Ca). Systems Journal of Solid State Chemistry, 2004.

A.Y. Borisevich and P.K. Davies. 1:2 Cation order in A(Li1/3(Nb,Ta)2/3)O3 Microwave Perovskites. Applied Physics Letters, 84(8), 1347-1349, 2004.

R. Tarvin and P.K. Davies.A- and B-Site Order in (Na1/2La1/2)(Mg1/3Nb2/3)O3 Perovskites. Journal of the American Ceramic Society, 859-864, 87(5), 2004.

A. Y. Borisevich and P. K. Davies. La(Li1/3Ti2/3)O3: A New 1:2 Ordered Perovskite. Journal of Solid State Chemistry, 170(1), 198-201, 2003.

P.K. Davies, A. Borisevich and M. Thirumal. Communicating with Wireless Perovskites: Cation Order and Zinc Volatilization. Journal of the European Ceramic Society, 23(14), 2461-66, 2003.

L. Farber and P.K. Davies. Influence of Cation Order on the Dielectric Properties of Pb(Mg1/3Nb2/3)O3 - Pb(Sc1/2Nb1/2)O3 (PMN-PSN) Relaxor Ferroelectrics. Journal of the American Ceramic Society, 86(11), 1861-66, 2003.

P. Juhas, W. Dmowski, I. Grinberg, T. Egami, A.M. Rappe and P.K. Davies. Correlations Between the Structure and Dielectric Properties of Pb(Sc2/3W1/3)O3-Pb(Ti/Zr)O3 Relaxors. AIP Conf. Proc., 677, 108, 2003.

D. Y. Suarez-Sandoval and P. K. Davies. Structure and Phase Stability of the CdTiO3-PbTiO3 System. Applied Physics Letters, 82(19), 3215-3217, 2003.

A. Y. Borisevich, and P. K. Davies. Crystalline Structure and Dielectric Properties of Li1+x-yNb1-x-3yTix+4yO3 M-phase Solid Solutions. Journal of the American Ceramic Society, 85(3), 573-578, 2002.

A. Y. Borisevich and P. K. Davies. Synthesis and Dielectric Properties of Li1-x+yTa1-x-3yTix+4yO3 M-phase Solid Solutions. Journal of the American Ceramic Society, 85(10), 2487-2491, 2002.

W. Dmowski, M. Akbas, T.Egami and P.K. Davies. Structure Refinement of Large Domain Relaxors in the Pb(Mg1/3Ta2/3)O3-PbZrO3 System. Journal of the Physics and Chemistry of Solids, 63(1), 15-22, 2002.

L. Farber, I. Levin, A. Borisevich, I.E. Grey, R.S. Roth, and P. K. Davies. Structural Study of Li1+x-yNb1-x-3yTix+4yO3 Solid Solutions. Journal of Solid State Chemistry, 166(1), 81-90, 2002.

L. Farber, M. Valant, M. A. Akbas, and P. K. Davies. Cation Ordering in Pb(Mg1/3Nb2/3)O3-Pb(Sc1/2Nb1/2)O3 (PMN-PSN) solid solutions. Journal of the American Ceramic Society, 85(9), 2319-2324, 2002.

B. Jancar, P. K. Davies, D. Suvorov and M. Valant. Cation arrangement and microstructure of dielectric ceramics based on the system Ba(Zn1/3Nb2/3)O3-Ba(Zn1/2W1/2)O3. Zbornik Referatov s Posvetovanja Slovenski Kemijski Dnevi, Maribor, Slovenia, Sept. 26-27, 2002 (Part 2), 808-813, 2002.

P. Juhas, P.K. Davies, M. A. Akbas. Chemical Order and Dielectric Properties of Lead Scandium Tungstate Relaxors. AIP Conference Proceedings, 626(Fundamental Physics of Ferroelectrics 2002), 108-116, 2002.

S.V. Kalinin, M. R. Suchomel, P.K. Davies, D.A. Bonnell. Potential and Impedance Imaging of Polycrystalline BiFeO3 Ceramics. Journal of the American Ceramic Society, 85(12), 3011-3017, 2002.


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Scott L. Diamond

Arthur E. Humphrey Professor of Chemical and Biomolecular Engineering and Bioengineering; Associate Director and Charter Member of Institute for Medicine and Engineering; Director of Biotechnology Program
Email: sld at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Mechano-biology, blood clotting and blood clot dissolving reactions, pharmacodynamics of thrombolytic therapies, endothelial gene therapy, proteomics of blood. Endothelial Cell Mechanobiology: This research ultilizes molecular and cell biology approches to explore issues related to cardiovascular disease of the arterial system. Our focus is on how physical forces generated by blood flow (hemodynamics) regulate blood vessel wall biology. Vascular surgeons and pathologists have long recognized that atherosclerotic lesions are localized at sites of low and disturbed blood flow. Additionally, physiologists have recognized that the endothelium plays an important role in matching the vessel diameter to the blood flow through vessel. Yet how does an endothelial cell respond to its hemodynamic environment? To date, our investigations have shown that the expression of several genes is altered in complete ways when endothelial cells are exposed to arterial levels of physical forces. We are interested in defining and promoting the hemodynamic regulation of endothelial phenotypes associated with enhanced vasodilatory activity and smooth muscle cell growth antagonism. Thrombosis and Thrombolytics: Thrombolytic therapy is well established in the US as a treatment for acute MI as well as for peripheral arterial and venous thrombosis. Thrombolytic treatment of stroke is in the developmental stage. A goal of our research is the advancement of large scale computations to simulate intravenous, intracoronary, or intrathrombic delivery of a combination of lytic agents to a given clot structure/comoposition for coronary, peripheral artery, and venous thrombolysis. We are conducting experimental and theoretical investigations of blood clotting and blood clot dissolving reactions under realistic hemodynamic conditions. We seek to define the quantitative relationship between the pharmacodynamics of a given thrombolytic therapy, the composition and location of a thrombus, and the consequent reperfusion time and flow rate. Particular attention is placed on the penetration rates of plasma constituents into thrombi (driven by hemodynamic pressures) and the consequent dissolution dynamics. We are advancing the use of computer simulation of the clot dissolving reactions using biphasic, multicomponent convection-dispersion-reaction equations for erodible fibrin structures with heterogeneous adsorption and reaction. Additionally, the design of catheters for local thrombolytics requires accurate understanding of coupled reaction-transport processes. Endothelial Gene Therapy: Gene transfer by nonviral methodologies (e.g. lipofection) are not efficient in cell populations with low mitotic rates. Unfortunately, cells are not actively dividing in many in vivo tissues that are potential clinical targets for gene therapy. While receptor targeting, fusigenic peptides, or endosome disrupting agents help overcome some of the first barriers that limit liposome-based gene delivery, virus free gene transfer using liposomes will have limited clinical utility because of the difficulty of transporting genetic material into the nucleus of a nondividing cell. We propose research to understand and potentially overcome this final rate limit of nuclear entry encounted with lipofection of nondividing cells. We seek to develop methodologies for delivering large genetic packages into the nucleus of nondividing cells. This will be critical for the success of nonviral mediated gene therapy in vivo and various tissue engineering applications where the low mitotic index of target cells would greatly limits the impact of many potential therapies.

Selected Recent Publications:
Price, A; Limberis, M; Gruneich, JA; Wilson, JM; Diamond, SL. Targeting viral-mediated transduction to the lung airway epithelium with the anti-inflammatory cationic lipid dexamethasone-spermine.MOLECULAR THERAPY, 12 (3): 502-509 SEP 2005.

ASimmons, G; Gosalia, DN; Rennekamp, AJ; Reeves, JD; Diamond, SL; Bates, P. Inhibitors of cathepsin L prevent severe acute respiratory syndrome coronavirus entry. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 102 (33): 11876-11881 AUG 16 2005.

Gosalia, D.N., Salisbury, C.M., Ellman, J.A., et al. High throughput substrate specificity profiling of serine and cysteine proteases using solution-phase flurogenic peptide microarrays. Molecular and Celluar Proteomics 4(5): 626-646 May 2005.

Ma, H.C., Horiuchi, K.Y., Wang, Y. et al. Nanoliter homogeneous ultra-high throughput screening microarray for lead discoveries and IC50 profiling. Assay and Drug Development Technologies 3(2): 177-187 April 2005.

Lo, K. Diamond, S.L. Blood coagulation kinetics: high throughput method for real-time reaction monitoring. Thrombosis & Haemostasis, 92(4), 874-82, October 2004.

Goel, M.S. and Diamond, S.L. Favor VII-a mediated tenase function on activated platelets under flow. Journal of Thrombosis and Haemostatis 2(8): 1402-1410 August 2004.

Price, A., Limberis, M., Gruneich, J. et al. Targeted gene transfer to lung airway epithelium using plasmid or adenoviral vectors formulated with an anti-inflammatory dexamethasone-spermine conjugate. Molecular Therapy 9:S189 Suppl. 1, May 2004.

Diamond, Scott L. High efficiency lipofection and gene correction of mouse embryonic stem cells using nuclear targeting technology. Abstracts of Papers, 227th ACS National Meeting, Anaheim, CA, United States, March 28-April 1, 2004, BIOT-121.

Eckmann, David M., Diamond, Scott L. Surfactants Attenuate Gas Embolism- induced Thrombin Production. Anesthesiology, 2004, 100(1), 77-84.

Gosalia, Dhaval N., Salisbury, Cleo M., Diamond, Scott L., Ellman, Jonathan A. Profiling serine protease substrate specificity with solution phase peptide microarrays. Abstracts of Papers, 227th ACS National Meeting, Anaheim, CA, United States, March 28-April 1, 2004, BIOT-114.

Gruneich, J. A., Price, A., Zhu, J., Diamond, S. L.. Cationic corticosteroid for nonviral gene delivery. Gene Therapy, 2004, 11(8), 668-674.

Ji JY. Diamond SL. Exogenous nitric oxide activates the endothelial glucocorticoid receptor. Biochemical & Biophysical Research Communications. 318(1):192-7, 2004 May 21.

Kadash, K. E., Lawrence, M. B., Diamond, S. L.. Neutrophil string formation: Hydrodynamic thresholding and cellular deformation during cell collisions. Biophysical Journal, 2004, 86(6), 4030-4039.

Ma, Haiching, Liu, Qin, Diamond, Scott L., Pierce, Eric A. Mouse embryonic stem cells efficiently lipofected with nuclear localization peptide result in a high yield of chimeric mice and retain germline transmission potency. Methods (San Diego, CA, United States) 2004, 33(2), 113-120.

J. M. Abrahams, S. L. Diamond. Biological and Future Management of Aneuryms. Management of Cerebral Aneurysms. Eds. P.D. LeRoux and H.R. Winn. Elsevier Science., 2003.

T.A. Doggett, G. Girdhar, A. Lawshe, J.L. Miller, I.J. Laurenzi, S.L. Diamond, T.G. Diacovo. Kinetic analysis of mutant GPIb alpha-vWF-A1 bonds reveal similarities between genetically distinct bleeding disorders. Blood., 2003.

M.Goel, S.L. Diamond. Neutrophil cathepsin G enhances prothrombinase and fibrin formation under flow by activating fibrinogen-adherent platelets. J. Biol. Chem. 278, 9458, 2003.

M. Goel, S. L. Diamond. Thrombosis. Encyclopedia of Biomaterials and Biomedical Engineering. Eds. G. E. Wnek, G. L. Bowlin. Marcel Dekker. In press, 2003.

D. Gosalia, S.L. Diamond. Printing chemical libraries for nanoliter fluid phase reactions. Proc. Natl. Acad. Sci. USA (Track II), 2003.

J. Y. Ji, H. Jing, S. L. Diamond. Shear stress enhances nuclear localization of endothelial glucocorticoid receptor and expression from the GRE promoter. Circ. Res. 92, 279, 2003.

Laurenzi, I.J., Diamond, S.L. Kinetics of random aggregation-fragmentation processes with multiple components. Physical Review E, v 67, n 5 1, May, 2003, p 051103/1-051103/5.

I.J. Laurenzi, S.L. Diamond. Kinetics of Reversible Aggregation and Gelation with Multiple Components. Phys. Rev. E. 67, 51103, 2003.

E. A. Pierce, Q. Liu, O. Igoucheva, H.Ma, R. Omarrudin, S. L. Diamond, K. Yoon. Oligonucleotide-directed single base DNA alterations in mouse embryonic stem cells. Gene Therapy. 10:24, 2003.

JM. Abrahams, C Song, MS Grady, SL Diamond, RJ Levy. Endovascular Microcoil Gene Delivery Using Immobilized Anti-adenovirus Antibody for Vector Tethering. Stroke. 33, 1376, 2002.

T. A. Doggett, G. Girdhar, A. Lawshe, D. W. Schmidtke, I. J. Laurenzi, S. L. Diamond, T. G. Diacovo. Selectin-like Kinetics and Biomechanics Promote Rapid Platelet Adhesion in Flow: The GPIb[alpha]-vWF Tether Bond. Biophysical J. 83, 194, 2002.

M. Goel, S. L. Diamond, Adhesion of Normal Erythrocytes to Activated Neutrophils, Activated Platelets, and Fibrin Polymerized from Plasma at Depressed Venous Shear Rates, Blood, 100, 3739, 2002.

Goel MS. Diamond SL. Adhesion of normal erythrocytes at depressed venous shear rates to activated neutrophils, activated platelets, and fibrin polymerized from plasma Blood. 100(10):3797-803, 2002 Nov 15.

Goel, M.S., Diamond, S.L. Adhesive interactions of erythrocytes with neutrophils, platelets and fibrin: Implications for deep vein thrombosis. Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, v 1, 2002, p 353.

Goel, M.S., Murciano, J.-C., Medinilla, S., Yamamoto, A., Cines, D.B., Muzykantov, V.R., Diamond, S.L. Dynamics of fibrin clot lysis under flow conditions by erythrocyte-linked tPA. Conference Proceedings. Second Joint EMBS-BMES Conference 2002. 24th Annual International Conference of the Engineering in Medicine and Biology Society. Annual Fall Meeting of the Biomedical Engineering Society (Cat. No.02CH37392), 2002, pt. 1, p 520 vol.1.

Gosalia, D.N., Diamond, S.L. High throughput screening using enzyme assay microarrays. International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, v 2, 2002, p 1628-1629.

Gruneich, J.A. , Diamond, S.L. Cationic corticosteroid vehicle for gene delivery. Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, v 1, 2002, p 550.

Ji, J.Y., Diamond, S.L. Shear stress activation of the glucocorticoid receptor transcription pathway. Conference Proceedings. Second Joint EMBS-BMES Conference 2002. 24th Annual International Conference of the Engineering in Medicine and Biology Society. Annual Fall Meeting of the Biomedical Engineering Society (Cat. No.02CH37392), 2002, pt. 1, p 651 vol.1.

I.J. Laurenzi, J.D. Bartels, S.L. Diamond. A general algorithm for exact numerical simulation of multi-component aggregation. J. Comput. Phys. 177, 418 2002.

I.J. Laurenzi, S.L. Diamond. Multicomponent Aggregation and Gel Formation via Simultaneous Convection and Diffusion. I.E.C.&R. 40: 413, 2002.

Laurenzi, I.J., Bartels, J.D., Diamond, S.L. A general algorithm for exact simulation of multicompon ent aggregation processes. Journal of Computational Physics, v 177, n 2, 10 April 2002, p 418-49.

Laurenzi, Ian J., Diamond, Scott L. Bidisperse aggregation and gel formation via simultaneous convection and diffusion. Industrial and Engineering Chemistry Research, v 41, n 3, Feb 6, 2002, p 413-420.

Laurenzi, I.J., Diamond, S.L. Dynamics of polymerization of macromolecules with multiple binding sites. Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, v 3, 2002, p 2204.

H. Ma, J. Zhu, M. Maronski, V.M.Y. Lee, M. Dichter, S.L. Diamond. Nonclassical nuclear localization signal peptides for high efficiency lipofection of primary neurons and neuronal cell lines. Neurosci. 111, 1, 2002.

E.Y.H. Park, M.J. Smith, E. S. Stropp, J. A. Diveietro, W. F. Walker, D.W. Schmidtke, S.L.Diamond, M.B. Lawrence. Comparison of PSGL-1 microbead and neutrophil rolling: Microvillus elongation stabilizes P-selectin clusters. Biophysical J. 82, 1835, 2002.

A. Subramanian, H. Ma, K.N. Dahl, J. Zhu, and S.L. Diamond. Adenovirus or HA-2 peptide assisted lipofection increases cytoplasmic plasmid in nondividing endothelium with little enhancement of transgene expression. J. Gene Med. 4:75, 2002.


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Dennis E. Discher

Professor of Chemical and Biomolecular Engineering, Bioengineering, and Mechanical Engineering and Applied Mechanics; Physics and Cell & Molecular Biology Graduate Groups; Adjunct Professor, Structural Biology – The Wistar Institute; Member, Institute of Medicine and Engineering,Graduate Group Chair, Chemical and Biomolecular Engineering.
Email: discher at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Biophysical Engineering & Polymers Lab, specifically membranes and soft interfaces within and across the fields of systems biophysics and polymers. Systems of direct interest include: protein folding and flexibility, blood cell adhesion and immunocompatability, block copolymer vesicles and worm-like micelles for drug delivery, physical determinants of stem cell and myocyte differentiation and disease, and nuclear envelope-chromatin interactions in isolated nuclei. Methods used range from molecular biology and single molecule AFM to micro-patterning and fluorescence ultra-microscopy. Modeling efforts range from pathway kinetics and continuum mechanics to computation intensive Monte Carlo and molecular dynamics.

Selected Recent Publications:
Geng Y, Discher DE. Hydrolytic Degradation of Poly(ethylene oxide)-block-Polycaprolactone Worm Micelles. J Am Chem Soc. 2005 Sep 21;127(37):12780-1.

Parthasarathy R, Subramanian S, Boder ET, Discher DE. Post-translational regulation of expression and conformation of an
immunoglobulin domain in yeast surface display. Biotechnol Bioeng. 2005 Sep 13.

Bhasin N, Law R, Liao G, Safer D, Ellmer J, Discher BM, Sweeney HL, Discher DE. Molecular Extensibility of Mini-dystrophins and a Dystrophin Rod Construct. J Mol Biol. 2005 Aug 30.

Sen S, Subramanian S, Discher D. Indentation and adhesive probing of a cell membrane with AFM: model and experiments. Biophys J. 2005 Aug 19.

Vijayan, K; Discher, DE; Lal, J; Janmey, P; Goulian, M. Interactions of membrane-active peptides with thick, neutral, nonzwitterionic bilayers.JOURNAL OF PHYSICAL CHEMISTRY B, 109 (30): 14356-14364 AUG 4 2005.

Y. Geng, F. Ahmed, N. Bhasin, and D.E. Discher. Visualizing worm micelle dynamics and phase transitions of a charged diblock copolymer in water. Journal of Physical Chemistry B 109: 3772-3779, 2005.

M. Griffin, H. Feng, M. Tewari, P. Acosta, M. Kawana, H.L. Sweeney, and D.E.Discher. g-Sarcoglycan deficiency increases cell contractility, apoptosis, and MAPK pathway activation but does not affect adhesion. Journal of Cell Science 118: 1405-1416, 2005. *Cover Article and accompanying Editor’s Highlight*

V. Ortiz, S. Nielsen, M.L. Klein, and D.E. Discher. Unfolding a linker between helical repeats. Journal of Molecular Biology 349: 638-647, 2005.

R.S. Leite, A.G. Brown, A.J. Engler, S. Parry and D.E. Discher. Proteomics reveals a hemoglobin fragment in cervicovaginal fluid from women in labor that potentiates the action of uterotonic agents. Journal of the Society for Gynecologic Investigation, 12(2): 263A-263A 561 Suppl S. February 2005.

R. Law, N. Bhasin and D. Discher. Application of probe microscopy to protein unfolding: Adsorption and ensemble analyses. Applications of Scanned Probe Microscopy to Polymers, 897: 162-181 2005.

Y. Kim, P. Dalhaimer, D. Christian, and D.E. Discher. Polymeric worm micelles as nano-carriers for drug delivery. Nanotechnology 16: S484-S491, 2005.

P. Dalhaimer, A. Engler, R. Parthasarthy, and D.E. Discher. Targeted worm micelles. Biomacromolecules 5: 1714-17.

G. Srinivas, D.E. Discher, and M.L. Klein. Self assembly and properties of diblock copolymers via coarse grain molecular dynamics. Nature Materials 3, 638(2004). With accompanying News and Views by R. Lipowsky.

P. Dalhaimer, O Wagner, P. Janmey, H. Aranda-Espinoza, and D.E. Discher. Flexibility transition and loop conformations in irreversible adsorption of polymers. (revision in review for Physical Review Letters).

L. Richert, A. Engler, D.E. Discher, and C. Picart. Elasticity of native and
cross-linked polyelectrolyte multilayer films. Biomacromolecules, v 5, n 5, September/October 2004, p 1908-1916.

K. N. Dahl, S.M. Kahn, and K.L. Wilson, and D.E. Discher. The nuclear envelope lamina network has elasticity and a compressibility limit suggestive of a molecular shock absorber. Journal of Cell Science 117: 4779-4786, 2004.

M. Griffin, S. Sen, H.L. Sweeney, and D.E. Discher. Adhesion-contractile
balance in myocyte differentiation. Journal of Cell Science 117: 5855-5863, 2004.

N. Bhasin, P. Carl. S. Harper, G. Feng, H. Lu, D.W. Speicher, and D.E. Discher. Chemistry on a single protein, VCAM-1, during forced unfolding. Journal of Biological Chemistry 279: 45865-45874, 2004.

P. Janmey and D.E. Discher. Holding it together in the ye. Nature, v 431, n 7009, October 7 2004, p 635-636.

F. Ahmed and D.E. Discher. Controlled release from polymersome vesicles blended with PEO-PLA or related hydrolysable copolymer. Journal of Controlled Release 96: 37-53, 2004. Best Paper Award 2004: Jorge Heller Award.

A. Eckhart, A.J. Engler, and D.E. Discher. Influence of protein synthesis on smooth muscle cells spreading. Molecular Biology of the Cell, 15:150A-150A 832 Suppl S. Nov 2004.

A.J. Engler, M. Berry, H.L. Sweeney, and D.E. Discher. Substrate compliance alters human mesenchymal stem cell morphology. Molecular Biology of the Cell, 15: 298A-298A 1652 Suppl S. November 2004.

P. Dalhaimer, H. Bermudez, and D.E. Discher. Biopolymer mimickry with polymeric worm micelles: MW-scaled flexibility, locked-in curvature, and coexisting microphases. Journal of Polymer Science - Polymer Physics B42: 168-172, 2004.

A. Engler, L. Bacakova, C. Newman, A. Popescu, M. Sheehan, and D.E. Discher. Substrate compliance versus ligand density in cell on gel responses. Biophysical Journal 86: 617-628, 2004.

Engler, L. Richert, J. Wong, C. Picart, and D.E. Discer. Surface probe
measurements of the elasticity of sectioned tissue and thin gels: correlations between subtrate stiffness and cell adhesion. Surface Science 570: 142-154, 2004.

R. Law, S. Harper, D.W. Speicher, and D.E. Discher. Influence of lateral
association on forced unfolding of antiparallel spectrin heterodimers. Journal of Biological Chemistry 279, 2004.

M. Sheehan, A. Engler, T. Barber, K.E. Healy, H.L. Sweeney, and D.E. Discher. Patterning, Prestress, and Peeling dynamics of myocytes. Biophysical Journal, Feb. 2004.

H. Bermudez, H. Aranda-Espinoza, D.A. Hammer, and D.E. Discher. Pore stability and dynamics in polymer membranes. Europhysics Letters 64: 4-10, 2003.

K.N. Dahl, R. Parthasarthy, C. Westhoff, and D.E. Discher. The role of human protein 4.2 in the attachment of CD47 to the red cell cytoskeleton. Blood web-published DOI 10.1182, 2003.

K.N. Dahl, C. Westhoff, and D.E. Discher. Fractional attachment of CD47 (IAP) to the erythrocyte cytoskeleton and visual co-localization with Rh protein complexes. Blood 101: 1194-1199, 2003.

P. Dalhaimer, F.S. Bates, and D.E. Discher. Single molecule visualization of stiffness-tunable, flow conforming worm micelles. Macromolecules 36: 6873-6877, 2003.

R. Law, G. Liao, S. Harper, G. Yang, D.W. Speicher, and D.E. Discher. Pathway shifts and thermal softening in temperature-coupled forced unfolding of spectrin domains. Biophysical Journal 85: 3286-3293, 2003.

R. Law, P. Carl, S. Harper, P. Dalhaimer, D.W. Speicher, and D.E. Discher. Cooperativity in forced unfolding of tandem spectrin repeats. Biophysical Journal 84: 533-544, 2003.

P. Photos, B.M. Discher, L. Bacakova, F.S. Bates, and D.E. Discher .
Polymersomes in vivo: increased stealth with both PEG density and molecular weight. Journal of Controlled Release 90: 323-334, 2003.

A. Popescu, R. Law, S. Kahn, and D.E. Discher. Adhesively tensed erythrocyte membrane: lysis dynamics and AFM probing. Biophysical Journal 85: 2746-2759, 2003.

H. Aranda-Espinoza, P. Carl, J-F. Letterier, P.A. Janmey, and D.E. Discher. Domain Unfolding in Neurofilament Sidearms: Effects of Phosphorylation and ATP. FEBS Letters 531: 397-401, 2002.

B.M. Discher', H. Bermudez' , Y.-Y. Won, D.A. Hammer, F.S. Bates, and D.E.Discher. Crosslinked copolymer vesicles with broadly tunable stability. Journal of Physical Chemistry B106: 2848-2854,2002.

D.E. Discher * and Adi Eisenberg. Polymer Vesicles. Science 297: 967-973, 2002. (*corresponding author of invited review).

C-M. Lee, M. Santore, F.S. Bates, and D.E. Discher. From membranes to melts, Rouse to reptation: diffusion in polymersome versus lipid bilayers. Macromolecules, 35: 323-326, 2002.


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Paul Ducheyne

Professor of Bioengineering; Professor of Orthopaedic Surgery Research; Member of the Institute for Medicine and Engineering; Director of Center for Bioactive Materials and Tissue Engineering
Email: ducheyne at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Since the late 1980's when the challenge of in vitro synthesis of bone tissue was first addressed, the investigation of mechanistic effects of materials on cellular functions, specifically cell attachment, proliferation, differentiation and extracellular matrix formation, have been central to this lab's activities. Analyses deal extensively with the interface zone between materials and cells and tissues, using both materials science techniques as well as life science methods. In addition, studies focus on the combined effects of microgravity and substrate material on cellular functions; and on material surface modification and controlled release of growth factors. Several tissue engineering applications are pursued. Specifically, the laboratory studies whether bone defects can be repaired with full return of mechanical function by treating defects with in vitro synthesized bone tissue. Another project involves the treatment of intervertebral disk degeneration with tissue engineered constructs.

Selected Recent Publications:
J. Yao, P. Ducheyne, S.R. Turteltaub. A three-dimensional nonlinear finite element analysis of the mechanical behavior of tissue engineered intervertebral discs under complex loads, Biomaterials, in press.

J. Yao, S. Radin, P.S. Leboy and P. Ducheyne, Solution mediated effect of bioactive glass in poly(lactic-co-glycolic acid)-bioactive glass composites on osteogenesis of marrow stromal cells, J. Biomed. Mater. Res.,in press.

W. Lai, J. Garino, C. Flaitz, P. Ducheyne, Excretion of resorption products from bioactive glass implanted in rabbit muscle, J. Biomed. Mater. Res., in press.

G.K. Toworfe, R.J. Composto, I.M. Shapiro, P. Ducheyne, Nucleation and growth of calcium phosphate on amine-, carboxyl- and hydroxyl-silane self assembled monolayers, Biomaterials. 2005 Aug 1.

M.H. Lee, R.M. Morris, D. Boettiger, R.J. Composto and P. Ducheyne. The effect of non-specific forces on short-term adhesion of cells to substrates of controlled physicochemical characteristics, Biomaterials, submitted

M.H. Lee, D.A. Brass, R. Morris, R. Composto, P. Ducheyne, The effect of non-specific interactions on cellular adhesion using model surfaces, Biomaterials26, 1721-1730 (2005)

J. Yao, S. Radin, P.S. Leboy and P. Ducheyne, The effect of bioactive glass content on synthesis and bioactivity of composite poly (lactic-co-glycolic acid)/bioactive glass substrate for tissue engineering, Biomaterials. 26, 1935-43 (2005)

V. Grigoriou, I.M. Shapiro, E.A. Cavalcanti-Adam, R.J. Composto, P. Ducheyne, C.S. Adams, Osteoblast apoptosis and survival is regulated by integrin-mediated surface attachment, J. Biolog. Chem., 280, 1733-9 (2005)

S. Radin, G. Reilly, G. Bhargave, P.S. Leboy, P. Ducheyne, Osteogenic effects of bioactive glass on bone marrow stromal cells, J. Biomed. Mater. Res., 73A: 21-29 (2005)

S. Radin, G. El-Bassyouni, E.J. Vresilovic, E. Schepers, P.Ducheyne, In vivo tissue response to resorbable silica xerogels as controlled release materials, Biomaterials, 26, 1043-1052 (2005)

G.K. Toworfe, R.J. Composto, C.S. Adams, I.M. Shapiro, and P. Ducheyne, Fibronectin Adsorption on Surface-activated Polydimethylsiloxane and its effect on Cellular Function, J. Biomed. Mater. Res., 71A: 449–461 (2004)

A. R. El-Ghannam, P. Ducheyne, M. Risbud, C. S. Adams, I. M. Shapiro, D. Castner, S. Golledge and R. J. Composto, Model Surfaces Engineered with Nanoscale Roughness and RGD Tripeptides Promote Osteoblast Activity, J. Biomed. Mater. Res., 68A, 615-627 (2004)

G.A. Silva, F.J. Costa, O.P. Coutinho, S. Radin, P. Ducheyne, R.L. Reis, Synthesis and evaluation of novel, bioactive composite starch – bioactive glass microparticles, J. Biomed. Mater. Res., 70A, 442-449 (2004)

J.C. Gan, P. Ducheyne, E. Vresilovic, W. Swaim, I.M. Shapiro, Intervertebral disc tissue engineering, II Characterization of the nucleus pulposus, Clin. Orthop., 411, 305 - 314 (2003)

J.C. Gan, P. Ducheyne, E. Vresilovic, I.M. Shapiro, Intervertebral disc tissue engineering, II Cultures of nucleus pulposus cells, Clin. Orthop., 411, 315 - 324 (2003)

W. Lai, J. Garino, P. Ducheyne, Silicon excretion from bioactive glass implanted in rabbit bone, Biomaterials, 23, 213- 217 (2002)

A. Huygh, E. Schepers, L. Barbier, P. Ducheyne, Microchemical transformation of bioactive glass particles of narrow size range followed for 24 months in vivo, J. Mat. Sci: Mat Med, 13, 315-320 (2002)

S. Radin, S. Falaize, M.H. Lee, P. Ducheyne, In vitro bioactivity and degradation behavior of silica xerogels intended as controlled release materials, Biomaterials, 23, 3113-3122 (2002).

R. Rajpurohit, M.V. Risbud, P. Ducheyne, E.J. Vresilovic and I.M. Shapiro, Phenotypic characteristics of the nucleus pulposus: Expression of hypoxia Inducing factor-1, glucose transporter-1 and MMP-2, Cell and Tissue Res., 308, 401-407 (2002)

T. Livingston, P. Ducheyne, J. Garino, The combination of osteoprogenitor cells and a bioactive ceramic scaffold promote bone repair, J. Biomed. Mater. Res., 62, 1-13 (2002)






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Dawn M. Elliott

Associate Professor of Orthopaedic Surgery and Bioengineering
Email: delliott at mail.med.upenn.edu
Personal Website

Research Interests:
Dr. Elliott studies the biomechanical function of orthopaedic soft tissues in health, aging, degeneration, injury and healing. Her primary focus is the intervertebral disc, which supports and distributes loads and permits motions of the spine. She also studies other tissues including tendon, ligament, meniscus, and articular cartilage. With age, the intervertebral disc undergoes progressive and irreversible degenerative changes that often lead to low back pain. Surgical treatment options are extremely limited and do not restore disc function. To describe the complex material behaviors of these tissues, including anisotropy, nonlinearity, inhomogeneity, and viscoelasticity, Dr. Elliott primarily uses mathematical models and mechanical tests. The mathematical models are applied to the study of human tissue as well as animal models which mimic human conditions. Mathematical models and mechanical tests, in combination with biochemical composition and microstructural measurements, lead to a better understanding of tissue function as well as the mechanisms for degeneration, injury and healing. In addition, the detailed knowledge of material behaviors gained through these methods is valuable in the development and evaluation of new treatments, such as surgical repair and tissue engineering.

Selected Recent Publications:

Sarver JJ and Elliott DM. Mechanical differences between lumbar and tail motion segments in the mouse. Journal of Orthopaedic Research 23(1):150-5, January 2005.

Yin L, and Elliott DM. A homogenization model of the annulus fibrosus. Journal of Biomechanics, v 38, n 8, August 2005, p 1674-1684.

Guerin HL and Elliott DM. The role of fiber-matrix interactions in a nonlinear fiber-reinforced strain energy model of tendon. Journal of Biomechanical Engineering, v127, n2, April 2005, p 345-350.

Elliott DM, Sarver JJ. Validation of the mouse and rat disc as mechanical models of the human lumbar disc. Spine, 29:713-722, 2004 (ISSLS Young Investigator Award Winner)

Johannessen W, Vresilovic EJ, Wright AC, Elliott DM. Intervertebral disc mechanics are restored following cyclic loading and unloaded recovery. Annals of Biomedical Engineering, 32(1): 70-76, 2004

Sarver JJ and Elliott DM. Altered disc mechanics in mice genetically engineered for reduced type I collagen. Spine 29(10):1094-8, May 15 2004.

Leonard BM, Shults J, Elliott DM, Stallings VA, Zemel BS. Interpretation of whole body dual energy X-ray absorptiometry measures in children: comparison with peripheral quantitative computed tomography. Bone 34(6):1044-52, June 2004.

Yin L and Elliott DM. A Biphasic and transversely isotropic mechanical model for tendon: application to mouse tail fascicles in uniaxial tension. Journal of Biomechanics 37:907-916, 2004

Elliott DM, PS Robinson, JA Gimbel, JJ Sarver, JA Abboud, RV Iozzo, LJ Soslowsky. Effect of altered matrix proteins on quasi-linear viscoelastic properties in transgenic mouse tail tendons, Annals of Biomedical Engineering 31:599-605, 2003

Lynch, HA, Johannessen W, Wu JP, Jawa A, Elliott DM. Effect of fiber orientation and strain-rate on the nonlinear uniaxial tensile material properties of tendon. Journal of Biomechanical Engineering, 125:726-731, 2003.

Sarver JJ, Robinson PS, Elliott DM. Methods for Quasi-linear viscoelastic modeling of soft tissue: Application to incremental stress relaxation experiments. Journal of Biomechanical Engineering, 125:754-758, 2003

Wyland DJ, Guilak F, Elliott DM, Setton LA, Vail TP. Chondropathy after meniscal tear or partial meniscectomy in a canine model, Journal of Orthopaedic Research 20:996-1002, 2002

Elliott DM., Jones R., Setton LA., Scully SP., Vail TP., Guilak F.: Joint degeneration following meniscal allograft transplantation in a canine model: mechanical properties and semiquantitative histology of articular cartilage. Knee Surgery, Sports Traumatology, Arthroscopy 10:109-118, 2002.

Elliott DM., Narmoneva DA., Setton LA.: Direct measurement of the Poisson's ratio of human patella cartilage in tension. Journal of Biomechanical Engineering 124: 223-228, 2002

Shin H, Allbeck J, Elliott DM, Badler NI: Modeling a deformable human arm for constrained reach analysis. Proceedings Digital Human Modeling Conference, Munich, Germany, BDI Berichte 1675: 217-228, SAE International (ISBN 0-7680-1025-X), 2002.


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Nader Engheta

H. Nedwill Ramsey Professor of Electrical and Systems Engineering, UPS Foundation Distinguished Educator
Email: engheta at ee.upenn.edu
Personal Website

Research Interests:
Metamaterials, Fields and Waves and Their Information Contents, Theory and Simulation of Nano-Optics, Optical Nanocircuits, and Near-Field Nano-Scale Devices and Systems, Nanostructured Materials Modeling, Miniaturized Antennas, Photonic Band Gap Structures, Reverse-Engineering of Polarization Vision and Information Sensing in Nature, Bio-Inspired/Biomimetic Sensing, Processing, and Displaying Polarization Information, Physics of Information Contents in Polarization Vision, Bio-Inspired Hyperspectral Imaging, Through-Wall Microwave Imaging, Electromagnetics/Electrophysics of Event-Related Brain Cortical Potentials (e.g., EEG), Mathematics of Fractional Operators and Fractal Domains.

Selected Recent Publications:
Engheta, N; Salandrino, A; Alu, A. Circuit elements at optical frequencies: Nanoinductors, nanocapacitors, and nanoresistors. PHYSICAL REVIEW LETTERS, 95 (9): Art. No. 095504 AUG 26 2005.

Alu A, Engheta N. Achieving transparency with plasmonic and metamaterial coatings. Phys Rev E, Part 2 July 2005 Jul;72 (1-2) :016623.

Engheta, N., Alu, A., and Salandrino, A. Nanocircuit elements, nano-transmission lines and nano-antennas using plasmonic materials in the optical domain. 2005 IEEE International Workshop on Antenna Technology: Small Antennas and Novel Metamaterials, 2005, p 165-8.

Engheta, N. and Ziolkowski, R.W. A positive future for double-negative metamaterials. IEEE Transactions on Microwave Theory and Techniques, 2005.

Al, A. and Engheta, N. Polarizabilities and effective parameters for collections of spherical nanoparticles formed by pairs of concentric double-negative, single-negative, and/or double-positive metamaterial layers. Journal of Applied Physics, 2005.

Mussetta, M., Bliznyuk, N., Pirinoli, P., Engheta, N., and Zieh R.E. Application of genetic algorithms for optimization of a FSS reflectarray antenna. Mathematical Methods in Electromagnetic Theory, MMET, Conference Proceedings, Conference Proceedings, 10th International Conference on Mathematical Methods in Electromagnetic Theory, 2004.

Zhu, J., Hoorfar, A., and Engheta, N. Peano antennas. IEEE Antennas and Wireless Propagation Letters, 2004.

Caiazzo, M., Maci, S., and Engheta, N. A metamaterial surface for compact cavity resonators. IEEE Antennas and Wireless Propagation Letters, 2004.

Bliznyuk, N., Engheta, N., and Hoorfar, A. An efficient hybrid computational technique for certain scattering and radiation problems in layered media. IEEE Aerospace Conference Proceedings, 2004.

Alu, A., Engheta, N., and Vegni, L. Metamaterial bilayers for enhancement of wave transmission through a small hole in a flat perfectly conducting screen. IEEE Antennas and Propagation Society, AP-S International Symposium, 2004.

McVay, J., Hoorfar, A., and Engheta, N. Small dipole antenna near peano high-impedance surfaces. IEEE Antennas and Propagation Society, AP-S International Symposium, 2004.

Alu, A., Engheta, N. Peculiar radar cross-section properties of double-negative and single-negative metamaterials. Proceedings of the 2004 IEEE Radar Conference (IEEE Cat. No.04CH37509), 2004, p 91-3.

Lin, S., Yemelyanov, K.M., Pugh, E.N. Jr., and Engheta, N. Polarization enhanced visual surveillance techniques. IEEE International Conference on Networking, Sensing and Control, 2004.

Bliznyuk, Natalia, Engheta, Nader. Numerical study of polarization-dependent focusing for a bilayer planar FSS reflective lens at millimeter wavelengths. Microwave and Optical Technology Letters, v 40, n 5, Mar 5, 2004, p 361-365.

McVay, J., Engheta, N., Hoorfar, A. High impedance metamaterial surfaces using Hilbert-curve inclusions. IEEE Microwave and Wireless Components Letters, v 14, n 3, March 2004, p 130-2.

Alu, A., Engheta, N. Guided modes in a waveguide filled with a pair of single-negative (SNG), double-negative (DNG), and/or double-positive (DPS) layers. IEEE Transactions on Microwave Theory and Techniques, v 52, n 1, pt.1, Jan. 2004, p 199-210.

Alu, Andrea, Engheta, Nader. Mono-modal waveguides filled with a pair of parallel epsilon-negative (ENG) and mu-negative (MNG) metamaterial layers. IEEE MTT-S International Microwave Symposium Digest, v 1, 2003, p 313-316.

Alu, A., Engheta, N. Pairing an epsilon-negative slab with a mu-negative slab: resonance, tunneling and transparency. IEEE Transactions on Antennas and Propagation, v 51, n 10, pt.2, Oct. 2003, p 2558-71.

Alu, Andrea, Engheta, Nader. Distributed-Circuit-Element Description of Guided-Wave Structures and Cavities Involving Double-Negative or Single-Negative Media. Proceedings of SPIE - The International Society for Optical Engineering, v 5218, 2003, p 145-155.

Alu, A., Engheta, N. Mode excitation by a line source in a parallel-plate waveguide filled with a pair of parallel double-negative and double-positive slabs. IEEE Antennas and Propagation Society International Symposium. Digest. Held in conjunction with: USNC/CNC/URSI North American Radio Sci. Meeting (Cat. No.03CH37450), 2003, pt. 3, p 359-62 vol.3.

Engheta, N. . Is Foster's reactance theorem satisfied in double-negative and single-negative media? Microwave and Optical Technology Letters, v 39, n 1, 5 Oct. 2003, p 11-14.

Engheta, N. Metamaterials with negative permittivity and permeability: background, salient features, and new trends. 2003 IEEE MTT-S International Microwave Symposium Digest (Cat. No.03CH37411), 2003, pt. 1, p 187-90 vol.1.

McVay, John, Hoorfar, Ahmad, Engheta, Nader. Radiation characteristics of microstrip dipole antennas over a high-impedance metamaterial surface made of Hilbert inclusions. IEEE MTT-S International Microwave Symposium Digest, v 1, 2003, p 587-590.

Yemelyanov, Konstantin M., Lin, Shih-Schon, Luis, William Q., Pugh Jr., Edward N., Engheta, Nader. Bio-inspired display of polarization information using selected visual cues. Proceedings of SPIE - The International Society for Optical Engineering, v 5158, 2003, p 71-84.

Jinhui Zhu, Hoorfar, A., Engheta, N. Bandwidth, cross-polarization, and feed-point characteristics of matched Hilbert antennas. IEEE Antennas and Wireless Propagation Letters, v 2, 2003, p 2-5.

Ziolkowski, Richard W., Engheta, Nader. Metamaterial Special Issue Introduction. IEEE Transactions on Antennas and Propagation, v 51, n 10 I, October, 2003, p 2546-2549.

Yemelyanov, K.M., Lo, M.A., Pugh, E.N., Jr., Engheta, N. Display of polarization information by coherently moving dots. Optics Express, v 11, n 13, 30 June 2003.

Alu, A., Engheta, N. Anomalous mode coupling in guided-wave structures containing metamaterials with negative permittivity and permeability. Proceedings of the 2002 2nd IEEE Conference on Nanotechnology (Cat. No.02TH8630), 2002, p 233-4.

Alu, A., Engheta, N. Radiation from a traveling-wave current sheet at the interface between a conventional material and a metamaterial with negative permittivity and permeability. Microwave and Optical Technology Letters, v 35, n 6, 20 Dec. 2002, p 460-3.

Engheta, N. Electromagnetics of complex media and metamaterials. Conference Proceedings. 2002 International Conference on Mathematical Methods in Electromagnetic Theory. MMET 02 (Cat. No.02EX554), 2002, pt. 1, p 175-80 vol.1.

Engheta, N. An idea for thin subwavelength cavity resonators using metamaterials with negative permittivity and permeability. IEEE Antennas and Wireless Propagation Letters, v 1, n 1, 2002, p 10-13.

Engheta, N. Thin absorbing screens using metamaterial surfaces. IEEE Antennas and Propagation Society International Symposium (IEEE Cat. No.02CH37313), 2002, pt. 1, p 392-5 vol.1.


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Nabil H. Farhat

Professor of Electrical and Systems Engineering
Email: farhat at ee.upenn.edu
Personal Website

Research Interests:
Development of Qualitative theory of corticonics (echoing electronics): This research seeks to identify salient features of cortical organization to be abstracted and used in the design of artificial systems with brain-like intelligence. Research involves concepts from nonlinear dynamics, bifurcation theory, Information Theory, and complexity driven self organization. Applications are being developed in the classification and generation of dynamic patterns, complexity driven learning, and computing with diverse attractors.

Selected Recent Publications:
Jie Yuan; Farhat, N.; Van der Spiegel, J. GBOPCAD: a synthesis tool for high-performance gain-boosted opamp design. IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, v 52, n 8, Aug. 2005, p 1535-44.


Nabil H. Farhat, "Dynamical Brain Model for Use in Data Processing Application", Patent publication, US 2004/0073415 A1, April 15, 2004.

Nabil H. Farhat. Corticonic Networks for Higher-Level Processing. Proc. IASTED Int. Conf. on Neural Networks and Computational Intelligence, Feb. 2004.

Nabil H. Farhat, Jie Yuan. A compensation-based optimization methodology for gain-boosted OPAMP. IEEE International Symposium on Circuits and Systems, 2004.

Hernandez, E.D.M., Geehyuk Lee, Farhat, N.H. Analog realization of arbitrary one-dimensional maps. IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, v 50, n 12, Dec. 2003, p 1538-47.

Farhat, Nabil H. Dynamic brain-state-in-a-box. Proceedings of SPIE - The International Society for Optical Engineering, v 4787, 2002, p 277-279.

Lee, Geehyuk, Farhat, Nabil H. Erratum: The double queue method: A numerical method for integrate-and-fire neuron networks (Neural Networks (2002) 14:6-7 (921-932) PII: S089360800100034X). Neural Networks, v 15, n 7, September, 2002, p 931.

Geehyuk Lee, Farhat, N.H. The bifurcating neuron network.2. An analog associative memory. Neural Networks, v 15, n 1, Jan. 2002, p 69-84.


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Leif H. Finkel

Professor of Bioengineering; Member of the Institute for Neurological Sciences; Member of the Institute for Medicine and Engineering; Member of the Institute for Research in Cognitive Science
Email: leif at seas.upenn.edu, leif at neuroengineering.upenn.edu
Personal Website   |   Research Website

Research Interests:
Our lab is devoted to trying to understand computation in real neural circuits, and to applications of these insights to neurological and psychiatric diagnosis and treatment. We are developing biophysical level simulations of neocortex, hippocampus and basal ganglia. Current applications are directed at understanding the alterations in brain function in schizophrenia, seizure disorders, and Parkinson’s disease. An underlying theme is the study of mechanisms of neural oscillations, synchronization, and integration of multiple inputs to a cell. We have close collaborations with colleagues working on electrophysiology, human intracranial EEG and deep brain recording, fMRI, and implanted seizure detection/termination devices.
A second focus of the lab is on visual perception. We are particularly interested in neural mechanisms of spatiotemporal pattern recognition and Bayesian integration with a current focus on biological motion perception.

Selected Recent Publications:
Wolf, J.A., Moyer, J.T., Lazarewicz, M., Contreras, D., Benoit-Marand, M., O’Donnell, P., and Finkel, L.H. (2005) NMDA:AMPA Ratio Impacts State Transitions and Entrainment to Oscillations in a Computational Model of the Nucleus Accumbens Medium Spiny Projection Neuron. J. Neuroscience (in press).

Lazarewicz, M.T., Das, S., and Finkel, L.H. Recognition of temporal event sequences by a network of cortical neurons. Neurocomputing, 2005.

Wolf, J.A., Moyer, J.T., and Finkel, L.H. The role of NMDA currents in state transitions of the nucleus accumbens medium spiny neuron. Neurocomputing, 2005.

Das, S., Lazarewicz, M., and Finkel, L.H. Principal component analysis of temportal and spatial information for human gait recognition. 26th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2004.

Geerts H., Finkel L. Behavioral problems in dementia and neuroleptics: A computational model of Risperidone's efficacy. BIOLOGICAL PSYCHIATRY 55: 13S-13S 45 Suppl. 8 APR 15 2004.

Geerts H, Lazarewicz M, Spiros A, et al. Galantamine benefits in Alzheimer's disease are related to increases in dopamine output. SCHIZOPHRENIA RESEARCH 60 (1): 135-135 Suppl. S MAR 15 2003.

Kim, D.H., Finkel, L.H. Hyperspectral image processing using locally linear embedding. Conference Proceedings. 1st International IEEE EMBS Conference on Neural Engineering 2003 (Cat. No.03EX606), 2003, p 316-19.

Murphy, T.A., Matlin, M., Finkel, L.H. Curvature covariation as a factor in perceptual salience. Conference Proceedings. 1st International IEEE EMBS Conference on Neural Engineering 2003 (Cat. No.03EX606), 2003, p 16-19.

Wolf, J.A., Finkel, L.H. A computational model of the Nucleus accumbens: network properties and their functional implications. Conference Proceedings. 1st International IEEE EMBS Conference on Neural Engineering 2003 (Cat. No.03EX606), 2003, p 214-17.

Geerts H, Dani J, Spiros A, et al. The increase of dopamine by galantamine explains its proven clinical benefits on non-cognitive scales. EUROPEAN NEUROPSYCHOPHARMACOLOGY 12: S380-S380 Suppl. 3 OCT 2002.

Geerts H. Finkel L. Carr R. Spiros A. Nicotinic receptor modulation: advantages for successful Alzheimer's disease therapy. Journal of Neural Transmission. Supplementum. (62):203-16, 2002.

Lazarewicz M, Spiros A, Finkel L, et al. Understanding the dual mode of action of galantamine using a virtual synaptic cleft. NEUROBIOLOGY OF AGING 23 (1): 447 Suppl. 1 JUL-AUG 2002.


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John E. Fischer

Professor of Materials Science and Engineering
Email: fischer at lrsm.upenn.edu
Personal Website

Research Interests:
Carbon nanotubes: The versatility of carbon chemical bonding allows thesynthesis of new allotropes (fullerenes, nanotubes) in addition to thewell-known graphite and diamond. Nanotubes can be envisioned as singlehexagonal graphite layers rolled into long, seamless cylinders a fewnanometers in diameter and 1000's of times longer. Believed to beatomically perfect, these exhibit spectacular mechanical and electricalproperties. As part of a large interdisciplinary team(www.seas.upenn.edu/mse/research/nanotubes.html) we are studying thefundamental properties and potential applications of this new class ofmaterials. Examples include tiny analogs of field effect transistors (the"tubeFET"), electrochemical devices for energy storage, high-strengthlight-weight composites, and multifunctional fibers which combine severaldesired properties in a single material. Fullerene materials: Buckminsterfullerene, a new crystalline form of purecarbon, is constructed from soccer ball-shaped 60-atom molecules("buckyballs'") which are atomic-scale analogs of Buckminster Fuller'sgeodesic domes. Interatomic bonds within a molecule are strong (as indiamond), while the bonding between molecules in the crystal is weak (likethe interlayer bonding in graphite thus facilitating the incorporation offoreign atoms and molecules into the large interstitial voids. Theimagination of materials scientists has been especially aroused by thediscovery of metallic behavior and superconductivity in alkalimetal-intercalated solid C60. We use solid state chemistry techniques,x-ray and neutron diffraction, and low-temperature electronic propertymeasurements to search for interesting new materials and to explain thesupeconducting behavior in these unusualmolecular solids.

Selected Recent Publications:
Zhou, W. ; Fischer, J.E.; Heiney, P.A.; Fan, H.; Davis, V.A.; Pasquali, M.; Smalley, R.E. Single-walled carbon nanotubes in superacid: X-ray and calorimetric evidence for partly ordered H/sub 2/SO/sub 4/. Physical Review B (Condensed Matter and Materials Physics), v 72, n 4, 15 July 2005, p45440-1-5.

W. Zhou, J. Vavro, N.M. Nemes, J.E. Fischer, F. Borondics, K. Kamaras, D.B. Tanner. Charge transfer and Fermi level shift in p-doped single-walled carbon nanotubes. Physical Review B (Condensed Matter and Material Physics), v 71, n 20, May 15 2005, p 205423-1-7.

J. Vavro, J. M. Kikkawa and J. E. Fischer. Metal-insulator transition in doped single-wall carbon nanotubes. Physical Review B, 2005.

C.Y. Nam, J.Y. Ki., and J.E. Fischer. Focused-ion-beam platinum nanopattering for GaN nanowires: Ohmic contacts and patterned growth. Applied Physics Letters, 2005.

J. Chmiola, G. Yushin, R.K. Dash, et al. Double-layer capacitance of carbide derived carbons in sulfuric acid. Electrochemical and Solid State Letters, 2005.

W. Zhou, P.A. Heiney, H. Fan, R.E. Smalley, J.E. Fischer. Single-walled carbon nanotube-templated crystallization of H 2SO4: Direct evidence for protonation. Journal of the American Chemical Society, 2005.

C. Y. Nam, D. Tham and J. E. Fischer. Effect of the polar surface on GaN nanostructure morphology and growth orientation. Applied Physics Letters, 2004.

H. Wang, W. Zhou, D. L. Ho, K. I. Winey, J. E. Fischer, C. J. Glinka and E. K. Hobbie. Dispersing single-wall carbon nanotubes with surfactants: A neutron scattering study. Nano Letters, 2004.

S. Badaire, V. Pichot, C. Zakri, P. Poulin, P. Launois, J. Vavro, C. Guthy, M. Chen, and J.E. Fischer. Correlation of properties with preferred orientation in coagulated and stretch-aligned single-wall carbon nanotubes. Journal of Applied Physics, 2004.

F. Du, R. C. Scogna, W. Zhou, S. Brand, J. E. Fischer and K. I. Winey. Nanotube networks in polymer nanocomposites: rheology and electrical conductivity Macromolecules , 2004.

L. M. Ericson, H. Fan, H. Peng, V. A. Davis, J. Sulpizio, Y. Wang, R. Booker, W. Zhou, J. Vavro, C. Guthy, S. Ramesh, C. Kittrell, G. Lavin, H. Schmidt, W. W. Adams, M. Pasquali, W.-F. Hwang, R. H. Hauge, J. E. Fischer and R. E. Smalley. Macroscopic neat single-walled carbon nanotube fibers. Science, 2004.

M.C. Llaguno, J.E. Fischer, A.T. Johnson, Jr.Observation of Thermopower Oscillations in the Coulomb Blockade Regime in a Semiconducting Carbon Nanotube. Nano Letters 4, 45, 2004.

W. Zhou, M. F. Islam, H. Wang, D. Ho, A. G. Yodh, K. I. Winey and J. E. Fischer. Small angle neutron scattering from single wall carbon nanotube suspensions: evidence of isolated rigid rods and rod networks.Chem. Phys. Letters 384, 185, 2004.

W. Zhou, J. Vavro, C. Guthy, K. I. Winey, J. E. Fischer, L. M. Ericson, S. Ramesh, R. Saini, V. A. Davis, C. Kittrell, M. Pasquali, R. H. Hauge and R. E. Smalley. Single wall carbon nanotube fibers extruded from super-acid suspensions: Preferred orientation, electrical and thermal transport. J. Appl. Physics 95, 649, 2004.

W. Zhou, K. I. Winey, J. E. Fischer, S. Kumar and H. Kataura. Out-of-plane preferred orientation of single wall carbon nanotube films. Appl. Phys. Letters 84, 2172, 2004.

R. Barsotti, Jr., J. E. Fischer, C. H. Lee, J. Mahmood, C. K. W. Adu and P. C. Eklund. Imaging, structural and chemical analysis of silicon nanowires. Quantum Confined Semiconductor Nanostructures, edited by J.M. Buriak, D.D.M. Wayner, F. Priolo, B. White, V. Klimov and L. Tsybeskov (Materials Research Society Symposium Proceedings 737, Mater. Res. Soc. Warrendale, PA, USA), 2003.

F. Du, J. E. Fischer and K. I Winey. A coagulation method to prepare single-walled carbon nanotube/PMMA composites and their modulus, electrical conductivity and thermal stability. J. Polymer Sci. B: Polymer Physics 41, 3333, 2003.

J. E. Fischer, W. Zhou, J. Vavro, M. C. Llaguno, C. Guthy, R. Haggenmueller, M. J. Casavant, D. E. Walters and R. E. Smalley. Magnetically aligned single wall carbon nanotube films: preferred orientation and anisotropic transport properties. J. Appl. Physics 93, 2157, 2003.

Y. Gogotsi, A. Nikitin, H. Ye, W. Zhou, J. E. Fischer, B. Ye, H. Foley and M. Barsoum. Nanoporous carbide-derived carbons with tuneable pore size. Nature Materials 2, 591, 2003.

R. Haggenmueller W. Zhou, J.E. Fischer and K.I. Winey, J. Nanosci. Mechanical and structural investigation of highly aligned single-walled carbon nanotubes in polymer composites. Nanotech. 3, 105, 2003.

I. Isaev, G. Salitra, A. Soffer, Y. S. Cohen, D. Aurbach and J. E. Fischer. A new approach for the preparation of anodes for Li-ion batteries based on activated hard carbon cloth with pore design. J. Power Sources 119-121, 28, 2003.

C. H. Lee, K. T. Kang, K. S. Park, M. S. Kim, H. S. Kim, H. G. Kim, J. E. Fischer and A. T. Johnson. The nano-memory devices of a single wall and peapod structural carbon nanotube field effect transistor. Japan J. Appl. Phys. Part 1, 42, 5392, 2003.
J. Vavro, M. C. Llaguno, J. E. Fischer, S. Ramesh, R. K. Saini, L. M. Ericson, V. A. Davis and R. E. Smalley Thermoelectric power of p-doped single-wall carbon nanotubes and the role of phonon drag. Phys. Rev. Letters 90, 065503, 2003.

Q. Xiong, R. Gupta, K.W. Adu, G. U. Sumanasekera, E. C. Dickey, D. Tham, J. E. Fischer and P.C. Eklund. Raman spectroscopy and structure of crystalline GaP nanowires. J. Nanosci. Nanotech. 3, 1, 2003.

W. Zhou, K. I. Winey, J. E. Fischer, S. Ramesh, R. K. Saini, L. M. Ericson, V. A. Davis, M. Pasquali, R. H. Hauge and R. E. Smalley. Preferred orientation in fibers of HiPco single wall carbon nanotubes from diffuse x-ray scattering. in Nanomaterials for Structural Applications, edited by C. Berndt et al., (Materials Research Society Symposium Proceedings 740, Mater. Res. Soc. Warrendale, PA, USA), 2003.

R. Barsotti, Jr., J. E. Fischer, C. H. Lee, J. Mahmood, C. K. W. Adu and P. C. Eklund. Imaging, structural and chemical analysis of silicon nanowires. Applied Phys. Lett. 81, 2866, 2002.

M. J. Biercuk, M. C. Llaguno, M. Radosavljevic, J. K. Hyun, A. T. Johnson and J. E. Fischer. Carbon nanotube composites for thermal management. Appl. Phys. Letters 80, 2767, 2002.

P. C. Eklund, B. K. Prahdan, U. J. Kim, J. E. Fischer, A. D. Friedman, B. C. Holloway, K. Jordan and M. W. Smith. Large-scale production of single-walled carbon nanotubes using ultrafast pulses from a free electron laser. Nano Letters 2, 561, 2002.
J. E. Fischer. Chemical doping of single-wall carbon nanotubes. Accounts of Chemical Research 30, 21, 2002.

J. Hone, M. C. Llaguno, M. Biercuk, A. T. Johnson, B. Batlogg, Z. Benes and J. E. Fischer. Thermal properties of carbon nanotubes and nanotube-based materials. Applied Physics A 74, 339, 2002.

J. C. Lasjaunias, K. Biljacovic, Z. Benes, J. E. Fischer and P. Monceau. Low temperature specific heat of single wall carbon nanotubes Phys. Rev. B 65, 113409, 2002.

N. M. Nemes, J. E. Fischer, K. Kamarás, D. B. Tanner and A. G. Rinzler. Electronic and structural properties of alkali doped SWNT. in Molecular Nanostructures, edited by H. Kuzmany, J. Fink, M. Mehring and S. Roth, AIP Conf. Proc. 633, 2002, p. 259.

P. Papanek, J. E. Fischer and N. S. Murthy. Low-frequency amide modes in different hydrogen-bonded forms of nylon-6 studied by inelastic neutron scattering and density-functional calculations. Macromolecules 35, 4175, 2002.

J. Vavro, M. C. Llaguno, B. C. Satishkumar, R. Haggenmueller, K. I. Winey, D. E. Luzzi, J. E. Fischer, G. U. Sumanasekera and P. C. Eklund. Electrical and thermal properties of C60-filled single wall carbon nanotubes. in Molecular Nanostructures, edited by H. Kuzmany, J. Fink, M. Mehring and S. Roth, AIP Conf. Proc. 633, 2002, p. 127.

J. Vavro, M. C. Llaguno, B. C. Satishkumar, D. E. Luzzi and J. E. Fischer. Electrical and thermal properties of C60-filled single-wall carbon nanotubes. Appl. Phys. Letters 80, 1450, 2002.


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Kenneth R. Foster

Professor of Bioengineering and Associate Professor of Electrical and Systems Engineering
Email: kfoster at seas.upenn.edu
Personal Website

Research Interests:
My interests relate to biomedical applications of nonionizing radiation from audio through microwave frequency ranges, and health and safety aspects of electromagnetic fields as they interact with the body. Another and somewhat broader topic of interest is technological risk, and impact of technology (principally, electrotechnologies) on humans.

Selected Recent Publications:
Foster, Kenneth R. Spectral lines: Building better lie detectors with neuroscience? IEEE Spectrum, v 42, n 7, July, 2005, p 5.

Wolpe PR, Foster KR, Langleben DD. Am J Bioeth. 2005 Spring;5(2):39-49. Emerging neurotechnologies for lie-detection: promises and perils.

L. Sheikh and K. R. Foster, The Left Ventricular Assist Device: A Multicultural Look at an Expensive Medical Technology 20th Annual IASTS Conference, Baltimore MD. Feb. 2005

K.R. Foster, Peering Into the Brain: Ethical Implications of New Polygraph Techniques, 20th Annual IASTS Conference, Baltimore MD. Feb. 2005

Peering into the Brain: New Methods of Polygraph Analysis. Bioethics conference, University of Pennsylvania, April 2005.

K. R. Foster, The mechanisms paradox, NATO Advanced Science Workshop, Yerevan, Armenia, March 2005

A. R.Sheppard et al. Biophysical Mechanisms For Effects of RF Energy: Report Of A Multiinvestigator Review: Nonthermal Mechanisms. 2005 Bioelectromagnetics Meeting, Dublin, June 2005

M. L. Swicord et al., Biophysical Mechanisms For Effects of RF Energy:Report Of A Multiinvestigator Review. I - Fields and Energy Absorption at Tissue, Cellular, and Molecular Levels. 2005 Bioelectromagnetics Meeting, Dublin, June 2005

K. R. Foster, Search for new mechanisms of interaction of radiofrequency fields with tissue, URSI conference, Coherence and Electromagnetic Fields in Bioplogical Systems, Prague, Czech Republic, July 2005.

K. R. Foster. Limiting Technology: Issues in Setting Exposure Guidelines For Radiofrequency Energy. In Ma Jian-Guo, Ed. 3rd Generation Mobile Communication Systems: Future Developments and Advanced Topics, Springer, in press.

J.E. Moulder, K.R. Foster, L.S. Erdreich. Mobile phones, mobile phone base stations and cancer: a review. International Journal of Radiation Biology, 2005.

K.R. Foster, M.H. Repacholi. Biological effects of radiofrequency fields: does modulation matter? Radiation Research, 2004.

P. Douglas, C. Morgan, H. Lee, K. R. Foster. LVAD As Destination Therapy - The Economic Dilemma. Technology in Society Magazine, 23(2):23-27, 2004.

K.R. Foster. Security Concerns, Scientific Societies and Globalization. IEEE Society on Social Implications of Technology conference, 2004.

Q. Balzano, A.R. Sheppard, K. R. Foster, M.L. Swicord. Field and temperature gradients in tissues near resonant short wires. Bioelectromagnetics Society Annual Meeting, 2004.

K.R. Foster, E.R. Adair. Modeling thermal responses in human subjects following extended exposure to radiofrequency energy. BioMedical Engineering OnLine, 2004.

K. R. Foster. Biological Effects of Radiofrequency Energy As Related to Health and Safety, Encyclopedia of RF and Microwave Engineering, Wiley, 2003.

K. R. Foster. Mechanisms of Interaction of ELF Fields and Biological Systems, Radiat. Prot. Dosim. 106(4), pp 301-310, 2003.

K. R. Foster, P. R. Wolpe, A. R. Caplan, Ethics and the Brain. IEEE Spectrum, June 2003.

K. R. Foster. Mightier Math. IEEE Spectrum, Feb. 2003.

K. R. Foster, J A. D'Andrea, S Chalfin, DJ Hatcher. Thermal modeling of millimeter wave damage to the primate cornea at 35 GHz and 94 GHz. Health Physics 84 (6): 764-769, 2003.

Laurence JA, McKenzie DR, Foster KR. Application of the heat equation to the calculation of temperature rises from pulsed microwave exposure. J Theor Biol. 222(3):403-5, 2003.

K. R. Foster. The precautionary principle - common sense or environmental extremism? IEEE Technology and Society Magazine, 21:8-13, 2002.

K. R. Foster. Herman Schwan. und die Expositionsgrenzwerte für Mikrowellenstrahlung. Naturwissenschaftliche Rundschau 55:638-645, Dec. 2002.

K. R. Foster et al. Electromagnetic hypersensitivity - - A COMAR technical information statement. IEEE Eng. Med. Biol. Sept/Oct 173-175, 2002.

K. R. Foster, C.-K. Chou, P. Riu. Use of "protective devices" for cellular telephones - A COMAR technical information statement. IEEE Eng. Med. Biol. May/June 2002, 105-106.

K. R. Foster, Herman P. Schwan. A Scientist and Pioneer in Biomedical Engineering. Annual Reviews of Biomedical Engineering 4:1-27, 2002.

Litvak E, Foster KR, Repacholi MH. Health and safety implications of exposure to electromagnetic fields in the frequency range 300 Hz - 10 MHz. Bioelectromagnetics 23:68-82, 2002.

P. Vecchia and K. R. Foster. Precaution and controversies-Regulating radiofrequency fields in Italy. IEEE Technology and Society Magazine. 21:23-27, 2002.

Ziskin MC, Adair ER, Bassen HI, Chou CK, Cohen J, D'Andrea JA, Doyle RL, Erdreich LS, Foster KR, Gandhi OP, Heynick LN, Klauenberg BJ, Leonowich JA, Lin JC, Meltz ML, Merritt JH, Miller RD, Murphy MR, Osepchuk JM, Petersen RC, Sena DT, Sutton CH, Tell RA, Varanelli AG, Walleczek J, Medical aspects of radiofrequency radiation overexposure, HEALTH PHYSICS,82(3):387-391 MAR 2002.


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Jean H. Gallier

Professor of Computer and Information Science
Email: jean at cis.upenn.edu
Personal Website

Research Interests:
Logic in computer science, automated deduction, unification, logic programming, compilers. New interests: geometry of curves and surfaces, CAGD, motion planning, classical mechanics, robotics, computer vision.

Selected Recent Publications:

Ramaswami, S., Siqueira, M., Sundaram, T., Gallier, J. and Gee, J. Constrained quadrilateral meshes of bounded size. International Journal of Computational Geometry and Applications, 15(1):55-98, February 2005.

Gallier, J.H., La Torre, S., Mukhopadhyay, S. Deterministic finite automata with recursive calls and DPDAs. Information Processing Letters, v 87, n 4, 31 Aug. 2003, p 187-93.

Gallier, J., Xu, D. Computing exponentials of skew-symmetric matrices and logarithms of orthogonal matrices. International Journal of Robotics & Automation, v 18, n 1, 2003, p 10-20.

Gallier, J.H Computing Exponentials of Real Matrices Diagonalizable Over C. January 2001.


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Louis A. Girifalco

University Professor
Email: lag at lrsm.upenn.edu
Personal Website

Research Interests:
Analysis of Technological Change; Theory of nanotube systems containing intercalated and intraccalated molecules; Statistical mechanics of one-dimensional systems. Theory of Graphitic Structures: Those cohesive and statistical mechanical properties of graphitic structures that depend on the van der Waals interactions among them are are being studied by using the potential energy interaction functions among them in the theory of the statistical mechanics of low-dimensional structures. The systems consist of nanotubes and ropes containing fullerene molecules. The properties include interaction energies, cohesive energy, heat capacity and other thermodynamic functions, as well as the nature of the clustering of fullerene molecules in these systems. The methods used include lattice gas theory, configurational integral theory and Monte Carlo calculationsTheory of Statistical Mechanics in One Dimension: Solutions exist for several one-dimensional statistical mechanical models in which molecules interact with nearest neighbor only. Studies are under way to extend these theories to non-nearest neighbor interaction for both lattice-gas and configurational integral methods.

Selected Recent Publications:
Khantha, M., Cordero, N.A., Molina, L.M., et al. Interaction of lithium with graphene: An ab initio study. Physical Review B 70 (12): Art. NO. 125422 September 2004.

Hodak, M., Girifalco, L.A. Systems of C/sub 60/ molecules inside (10,10) and (15,15) nanotube: a Monte Carlo study. Physical Review B (Condensed Matter and Materials Physics), v 68, n 8, 15 Aug. 2003, p 85405-1-7.

Girifalco, L.A., Hodak, M. One-dimensional statistical mechanics models with application to peapods. Applied Physics A (Materials Science Processing), v A76, n 4, March 2003, p 487-98.

Hodak, M., Girifalco, L.A. Ordered phases of fullerene molecules formed inside carbon nanotubes. Physical Review B (Condensed Matter and Materials Physics), v 67, n 7, 15 Feb. 2003, p 75419-1-4.

Hodak, M. , Girifalco, L.A. Cohesive properties of fullerene-filled nanotube ropes. Chemical Physics Letters, v 363, n 1-2, 2 Sept. 2002, p 93-8.

Girifalco, L.A. , Hodak, M. Van der Waals binding energies in graphitic structures. Physical Review B (Condensed Matter and Materials Physics), v 65, n 12, 15 March 2002, p 125404/1-5.


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Eduardo D. Glandt

Dean, School of Engineering and Applied Science; Robert D. Bent Professor of Chemical and Biomolecular Engineering
Email: eglandt at seas.upenn.edu
Personal Website

Research Interests:
Molecular simulations of gas adsorption, polymer adsorption, barriers to mass transfer in catalysts and adsorbents, modeling of industrially relevant adsorbents. Molecular Simulations of Gas Adsorption: This work applies molecular models and computer simulation techniques to investigate how the microstructure of a porous material affects its physical and chemical properties and, especially, its capacity as an adsorbent. The goal is to offer guidance in the preparation of high-capacity adsorbents. For example, adsorbed natural gas offers attractive features as a potential fuel for urban transportation: the filling pressure is relatively low (300-400 psig) compared to that of compressed gas, while the energy density may be as high as 20% of that for liquified natural gas. Important practical problems that affect the implementation of adsorption systems can be readily examined by molecular simulation. They include (i) heat effects, which severely limit the feasible rates of adsorption and desorption; (ii) multicomponent separation, which leads to a partial saturation of the substrate by traces of heavier components; and (iii) the presence of very active impurities, such as water vapor, which results in capillary condensation and pore blockage. Thermodynamics and Gelation of Polymer Solutions: Some powerful techniques developed for the molecular modeling of simple liquids, the so-called integral-equation theories, can now be extended to the much more challenging problem of describing the thermodynamics and structure of polymer solutions and melts. Our research program is a theoretical and experimental study of the formation of physical gels, such as those used in foods and similar applications. The "gelation phase diagram" is similar to but more complex than a thermodynamic phase diagram. This work is also concerned with the configuration and thermodynamic properties of polymer molecules in random porous media. Their distribution and retention are important in chromatographic separation processes as well as in oil-recovery applications. Transport Properties of Random Materials: The effective properties (e.g. diffusivity, thermal and electrical conductivities, permeability to fluid flow, and even chemical reactivity) of a porous material are strong functions of the geometric structure of the solid and also of its topological characteristics: the connectedness of the solid and of the pores. These properties can be estimated in a very intuitive way by reproducing the structure of the material in a computer and by simulating the paths followed by individual molecules as they diffuse and are convected through the pore space. Concepts from percolation theory, the science of connectivity, must also be applied in order to take into account that in large systems a fraction of the pores are actually not accessible to transport and reaction.

Selected Recent Publications:

Danwanichakul, P. and Glandt, E.D. Percolation and jamming in structures built through sequential deposition of particles. Journal of Colloid and Interface Science, 2005.

Danwanichakul P. and Glandt, E.D. Particle correctedness and cluster formation in sequential depositionos of particles: Integral-equation theory. Journal of Chemical Physics, 2004.

Schmidt, Ferdinand P., Luther, Joachim, Glandt, Eduardo D. Influence of adsorbent characteristics on the performance of an adsorption heat storage cycle. Industrial and Engineering Chemistry Research, v 42, n 20, Oct 1, 2003, p 4910-4918.

Danwanichakul, P., Glandt, E.D. Sequential quenching of square-well particles. Journal of Chemical Physics, v 114, n 4, 22 Jan. 2001, p 1785-90.


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Keith J. Gooch

Assistant Professor of Bioengineering; Assistant Professor of Chemical and Biomolecular Engineering; Member of the Institute for Medicine and Engineering
Email: kgooch at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Our research is in the general areas of tissue-engineering and gene therapy. A brief description of each of the mainprojects in the lab are below. Tissue-engineered blood vessels for bypass grafts: There is a sizable unmet demand for effective small-diameter vascular prostheses for use in coronary bypass surgery. Currently, the best replacements for occluded arteries areautologous arteries, which have a cumulative patency rate of 93% after 5 years. Donor veins of appropriate dimensions are more readily available and are frequently used despite their substantially lower patency (45% after 5 years). We are currently exploring two alternative approaches to generate vascular grafts. The first approach attempts to improve the patency of autologous veins by exposing the veins to the appropriate mechanical environment (arterial pressure) outside the body prior to use as bypass graft, thereby directing the remodeling of the vessel thus improving the quality of the veins. The second approach attempts to improve the supply of autologous arteries by exposing the arteries to the appropriate mechanical environment (longitudinal strain) outside prior to use as bypass graft, thereby directing the growth of the vessel thus improving the quantity of graftable arteries. Tissue-engineered microvascular networks for gene therapy: A second project with a strong cardiovascular focus is the use of tissue-engineered microvascular networks for gene therapy. The enormous potential of gene therapy to improve human health remains largely unrealized due to a number of obstacles. One obstacle is the introduction of genetically modified cells to a location in the body from which the desired gene product may reach its required location. For a number of conditions (e.g., pituitary dwarfism and hemophilia) efficient delivery of the new protein to the blood is required. Tissue-engineered networks of genetically modified endothelialc ells have many promising characteristics that may permit efficient delivery of proteins to the blood. We have developed such as a system and have demonstrated its ability to delivery therapeutic levels of a model protein (human growth hormone) to the blood stream in experimental animals. We are currently exploring the ability of this system to deliver other proteins that may be clinically useful as well as modifications to the system that could prepare it for eventual use in humans.Tissue-engineered beta cells from pancreatic ductal epithelial cells: The goal of this project is to combine existing understanding of beta cell development with techniques previously employed to generate tissues invitro to create tissue-engineered islets by recapitulating in vitro processes known to occur in vivo during embryonic development and in adults in response to specific stimuli.

Selected Recent Publications:

Gusic RJ, Myung R, Petko M, Gaynor JW, Gooch KJ. Mechanical properties of native and ex vivo remodeled saphenous veins. J Biomech (in press).

Nichol JW, Petko M, Myung RJ, Gaynor JW, and Gooch KJ Hemodynamic Conditions Modulate the Growth, Remodeling, and Mechanical Properties of Arteries Subjected to Increased Axial Loading Ex Vivo. Ann. Biomed. Eng (in press).

Sieminski AL, Hebbel RP, and Gooch KJ. Human blood outgrowth endothelial cells have reduced dependence on growth factors and phorbol esters for elongation, network formation, and lumen formation during in vitro angiogenesis. Tissue Eng (in press).

Gusic RJ, Myung R, Petko M, Gaynor JW, and Gooch KJ. Shear stress and pressure modulate saphenous vein remodeling ex vivo. J. Biomech. 2005 September, 38(9):1760-9. Epub 2005 Jan 4.

Nichol JW, Petko M, Myung RJ, Gaynor JW, and Gooch KJ. Hemodynamic conditions alter axial and circumferential remodeling of arteries engineered ex vivo. Annals of Biomedical Engineering, 2005.

Stachelek SL, Alferiev I, Choi H, et al. Cholesterol-derivatized polyurethane: Characterization and endothelial cell adhesion. Journal of Biomedicals Materials Research, 2005.

Schreiber FS, Deramaudt TB, Brunner T, Boretti MI, Gooch KJ, Enders GH, Bernhard EJ, and Rustgi AK. Successful growth and characterization of mouse pancreatic ductal epithelial cells: properties of Ki-ras oncogene. Gastroenterology, 2004.

Sieminski AL and Gooch KJ. Salmon fibrin supports an increased number of sprouts and decreased degradation while maintaining sprout length relative to human fibrin in an in vitro angiogenesis model. J Biomaterials Science. Polymer Edition. 15(2):237-42. 2004.

Sieminski AL, Hebbel RP, and Gooch KJ. The Relative Magnitudes of Endothelial Force Generation and Matrix Stiffness Modulate Capillary Morphogenesis In Vitro. Exp Cell Res 297(2):574-84. 2004.

Clerin V, Nichol J, Petko M, Myung RJ, Gaynor JW and Gooch KJ. Tissue Engineering of Arteries by Directed Remodeling of Intact Arterial Segments. Tissue Eng, 9(3):461-72. 2003.

Lawrence AR, Gusic RJ and Gooch KJ. Noninvasive Determination of Perfused Artery Dimensions Ex Vivo Using a Pressure-Diameter Relationship. Biorheology 40 (5):523-9. 2003.

Nichol JW and Gooch KJ. Characterization Of Collagen And Elastin Remodeling In Engineered Arteries. ASME Intl Mech Engr Congress & Expo Nov 2003.

Boretti MI and Gooch KJ. Cell Clustering Enhances the Tissue Engineering of Beta Cells from Pancreatic Ductal Epithelial Cells. Biomedical Engineering Society Annual Meeting, Nashville, TN. Oct 2003.

Gusic RJ, Myung R, Petko M, Gaynor JW, and Gooch KJ. Shear Stress and Pressure Modulates Saphenous Vein Remodeling Ex Vivo. Biomedical Engineering Society Annual Meeting, Nashville, TN. Oct 2003.

Lawrence AR and Gooch KJ. Effects of Transmural Pressure on Arteries Perfused Long-Term Ex Vivo. Biomedical Engineering Society Annual Meeting, Nashville, TN. Oct 2003.

Lawrence AR and Gooch KJ. Mechanical Properties of Porcine Carotid Arteries Perfused Under Hypertensive Pressure Long-Term Ex Vivo. Frontiers in Biomechanics Conference, Nashville, TN. Oct 2003.

Nichol JW and Gooch KJ. Hemodynamic Environment and Axial Strain Interact to Alter Growth, Remodeling of Engineered Arteries. Biomedical Engineering Society Annual Meeting, Nashville, TN. Oct 2003.

Nichol JW and Gooch KJ. Interactions between hemodynamic environment and axial strain alter remodeling in engineered arteries ex vivo. Frontiers in Biomechanics Conference, Nashville, TN. Oct 2003.

Sieminski AL and Gooch KJ. Balance Between Endothelial Force Generation and Matrix Stiffness in an In Vitro Angiogenesis Model. Biomedical Engineering Society Annual Meeting, Nashville, TN. Oct 2003.

Sieminski AL, Hebbel RP, Gooch KJ. Improved Microvascular Network Formation by Bone Marrow-Derived Endothelial Cells. Biomedical Engineering Society Annual Meeting, Nashville, TN. Oct 2003.

Blunk T, Sieminski AL, Croft C, Courter DL, Chieh J, Khurana JS, and Gooch KJ. Bone Morphogenetic Protein 9: A Potent Modulator Of Engineered Cartilage Development In Vitro. ASME Summer Bioengineering Conference. Jun 2003.

Boretti MI and Gooch KJ. Induced Cell Clustering Enhances Islet Beta Cell Formation from Pancreatic Ductal Epithelial Cells. ASME Summer Bioengineering Conference. Jun 2003.

Daxinin S, Sieminski AL, Smith J, Gooch KJ, and Shastri P. Retention of Endothelial Cells Under High Shear Stress on Micropatterned Polyurethane Surfaces. ASME Summer Bioengineering Conference. Jun 2003.

Gusic RJ, Myung R, Petko M, Gaynor W, and Gooch KJ. The Effects of Shear Stress and Pressure on Saphenous Vein Remodeling Ex Vivo. ASME Summer Bioengineering Conference. Jun 2003.

Lawrence AL, Gusic RJ, and Gooch KJ. Noninvasive Determination of Perfused Artery Dimensions Ex Vivo Using a Pressure-Diameter Relationship. ASME Summer Bioengineering Conference. Jun 2003.

Nichol JW and Gooch KJ. Characterization of Collagen Production and Active Remodeling Present in Engineered Arteries Created by Directed Remodeling. ASME Summer Bioengineering Conference. Jun 2003.

Sieminski AL, Hebbel RP, and Gooch KJ. Improved Microvascular Network Formation By Adult Human Blood Outgrowth Endothelial Cells Relative to Mature Human Endothelial Cells. ASME Summer Bioengineering Conference. Jun 2003.

Blunk T, Sieminski AL, Gooch KJ, Courter DL, Hollander A, Nahir AM, Langer R, Vunjak-Novakovic G, and Freed LE. Differential Effects of Growth Factors on Tissue-Engineered Cartilage. Tissue Eng, 8(1):73-84; 200.2

Clerin V, Gusic RJ, O'Brien R, Kirshbom PM, Myung RJ, Gaynor JW, and Gooch KJ. Mechanical environment, donor age, and presence of endothelium interact to modulate porcine artery viability ex vivo. Ann. Biomed. Eng, 30(9):1117-27; 2002.

Gooch KJ, Blunk T, Courter DL, Sieminski AL, Vunjak-Novakovic G, Freed LE. Bone Morphogenetic Proteins-2, -12, and -13 modulate in vitro development of engineered cartilage. Tissue Eng, 8(4):591-601; 2002.

Nichol JW, Clerin VM, and Gooch KJ. Tissue-engineered arteries created by directed remodeling of intact arterial segments. ASME IMECE Bioengineering Division, New Orleans, LA. Nov 2002.

Boretti M and Gooch KJ. Induced Cell Clustering Enhances Islet Beta Cell Formation from Pancreatic Ductal Epithelial Cells. Biomedical Engineering Society Annual Meeting, Houston, TX. Oct 2002.

Gusic RJ and Gooch KJ. Biomechanics of Porcine Saphenous Veins Ex Vivo. Biomedical Engineering Society Annual Meeting, Houston, TX. Oct 2002.

Lawrence AR, Gusic RJ, and Gooch KJ. Determination of wall thickness from pressure-diameter data from perfused excised or tissue-engineered vessels. Biomedical Engineering Society Annual Meeting, Houston, TX. Oct 2002.

Nichol JW, Clerin V, and Gooch KJ. Tissue engineering of intact arterial segments by directed remodeling. Biomedical Engineering Society Annual Meeting, Houston, TX. Oct 2002.

Sieminski AL, Hebbel RP, and Gooch KJ. Tissue Engineered Microvascular Networks from Adult Human Endothelial Progenitor Cells. Biomedical Engineering Society Annual Meeting, Houston, TX. Oct 2002.

Sieminski AL, Padera R, Blunk T, Gooch KJ. Systemic Delivery of hGH Using Genetically Modified Tissue-Engineered Microvascular Networks: Prolonged Delivery and Endothelial Survival with Inclusion of Non-Endothelial Cells. Tissue Eng, 8(6): 1057-1069; 2002.

Schreiber FS, Harada H, Boretti MB, Gooch KJ and Rustgi A. Activation of mutant Ki-ras in murine pancreatic ductal cells induces cell cycle regulators. Digestive Disease Week, San Francisco, CA. May 2002.

Sieminski AL and Gooch KJ. Microvascular Networks for Gene Therapy. Keystone Conference on Biological Response to the Extracellular Matrix. Banff Alberta, Canada. Feb 2002.


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Raymond J. Gorte

Russell Pearce and Elizabeth Crimian Heuer Professor of Chemical and Biomolecular Engineering; Professor of Materials Science and Engineering
Email: gorte at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Automotive Emissions Control Catalysis: Current automotive catalysts are a complex mixture of precious metals and various oxides. Meeting present standards for NO, CO, and hydrocarbons requires that the interactions between the various components be carefully engineered. This is especially true for the oxygen-storage component, a critical part of the catalyst which controls the oxygen stoichiometry by means of a reducible oxide, usually ceria. We have shown that the reducibility of ceria, and its interaction with the precious-metal components, depends strongly on the structure of the ceria and the presence of various dopants. We use a wide variety of techniques to study this affect, range from measurements of reaction kinetics, electron microscopy, isotope-labelling studies, and low-angle, x-ray scattering. The goal is to develop a better understanding of those factors which influence the catalytic properties.

Electrodes for Solid-Oxide Fuel Cells: Solid-Oxide Fuel Cells (SOFC) offer an attractive alternative to gas turbines for generating electricity. In SOFCs, oxygen anions are transported through an oxide membrane and react with the fuel at the anode. A major problem is that typical anode materials are only active enough to work with hydrogen, so that practical fuels, like methane, must first be steam reformed to hydrogen. This imposes severe limitations on the operating conditions. We are using concepts developed from our program in automotive catalysis to synthesize anodes which are active for the direct oxidation of hydrocarbon fuels. This work involves building model SOFCs and performing spectroscopic studies of the anodes.

Selected Recent Publications:
"Cu-Co Bimetallic Anodes for Direct Utilization of Methane in Solid Oxide Fuel Cells", Shung-Ik Lee, Kipyung Ahn, John M. Vohs, and Raymond J. Gorte, Electrochemical & Solid State Letters, 8 (2005) A48-51.

"Comparison of the Performance of Cu-CeO2-YSZ and Ni-YSZ Composite SOFC Anodes with H2, CO, and Syngas", O. Costas-Nunes, R. J. Gorte, and J. M. Vohs, Journal of Power Sources, 141 (2005) 241-249.

"Fabrication of Direct-Utilization SOFC from a Single Laminated Structure", Kipyung Ahn, Yingyi Huang, Shung-Ik Lee, John M. Vohs, and Raymond J. Gorte, Proceedings of the Electrochemical Society, in press.

"Highly Sulfur Tolerant Cu-Ceria Anodes for Solid Oxide Fuel Cells", Hongpeng He, J. M. Vohs, and R. J. Gorte, Electrochemical and Solid State Letters, 8 (2005) A279-280.

"Carbonaceous deposits in direct utilization hydrocarbon SOFC anode", H. He, J. M. Vohs, and R. J. Gorte, Journal of Power Sources, 144 (2005) 135-140.

"Studies of the Water-Gas-Shift Reaction with Ceria-Supported Precious Metals", S. Zhao and R. J. Gorte, Catalysis Today, 104 (2005) 18-24.

"Characterization of LSM-YSZ Composites Prepared by Impregnation Methods", Y. Huang, J. M. Vohs, and R. J. Gorte, Journal of the Electrochemical Society, 152 (2005) A1347-53.

"High mobility of ceria films on zirconia at moderate temperatures", O. Costa-Nunes, R. J. Gorte, and J. M. Vohs, Journal of Materials Chemistry, 15 (2005) 1520 - 1522.

"Recent Developments Towards Commercialization of Solid Oxide Fuel Cells", R. J. Gorte, AIChE Journal, accepted.

"Enhanced thermal stability of SOFC anodes made with CeO2-ZrO2 solutions", K. Ahn, H. He, J. M. Vohs, and R. J. Gorte, Electrochemical and Solid State Letters, 8 (2005) A414-17.

"Influence of Composition and Cu Impregnation Method on the Performance of Cu/CeO2/YSZ SOFC Anodes", S. Jung, C. Lu, H. He, K. Ahn, R. J. Gorte, and J. M. Vohs, Journal of Power Sources, accepted.

"A Study of Carbon Formation and Prevention in Hydrocarbon-Fueled SOFC", T. Kim, G. Liu, M. Boaro, S.-I. Lee, J. M. Vohs, R. J. Gorte, O. H. Al-Madhi, B. O. Dabbousi, Journal of Power Sources, accepted.

‘'Structure and Thermal Stability of Ceria Films Supported on YSZ(100) and α-Al2O3(0001)", O. Costas-Nunes, R. Ferrizz, R. J. Gorte, and J. M. Vohs, Surface Science, accepted.

"Novel Cathodes Prepared by Impregnation Procedures", Y. Huang, J. M. Vohs, and R. J. Gorte, Proceedings of the Electrochemical Society, Vol. 2005-07, 1735-44.

"The Effect of Polarization on LSM-YSZ Composite Cathodes", S. McIntosh, Y. Huang, J. M. Vohs, and R. J. Gorte, Proceedings of the Electrochemical Society, Vol. 2005-07, 1549-54.

"Novel Bimetallic Anodes for Direct Utilization of Hydrocarbon Fuels", K. Ahn, S.-I. Lee, J. M. Vohs, and R. J. Gorte, Proceedings of the Electrochemical Society, Vol. 2005-07, 1360-68.

"Fabrication of SOFC Electrodes by Impregnation Methods", Y. Huang, J. M. Vohs, and R. J. Gorte, Proceedings of the 107th American Ceramic Society Meeting, accepted.

"An Investigation of NOx Storage on Pt-BaO-Al2O3", G. Zhou, T. Luo, and R. J. Gorte, submitted.

"Characterization of Acylating Intermediates Formed in H-ZSM-5", O. Kresnawahjuesa, R. J. Gorte, and David White, Journal of Molecular Catalysis A, 208 (2004) 175-185.

"Advanced Anodes for High Temperature Fuel Cells", A. Atkinson, S Barnett, R. J. Gorte, J.T.S. Irvine, A.J. McEvoy, M.B. Mogensen, S. Singhal, and J. Vohs, Nature Materials, 3 (2004) 17-27.

"The Activity of Fe-Pd Alloys for the Water-Gas Shift Reaction", S. Zhao and R. J. Gorte, Catalysis Letters, 92 (2004) 75-80.

"Measurement of Electrode Overpotentials for Direct Hydrocarbon Conversion Fuel Cells", V. Krishnan, R. J. Gorte, and J. M. Vohs, Solid State Ionics, 166 (2004) 191-197.

"Deactivation of the Water-Gas-Shift Activity of Pd/Ceria by Mo", S. Zhao, T. Luo, and R. J. Gorte, Journal of Catalysis, 221 (2004) 413-420.

"Low-Temperature Method for Fabrication of Oxide Composites", H. He, Y. Huang, J. Regal, M. Boaro, J. M. Vohs, and R. J. Gorte, Journal of the American Ceramic Society, 87 (2004) 331-336.

"An Examination of Carbonaceous Deposits in Direct-Utilization SOFC Anodes", S. McIntosh, H. He, S.-I. Lee, O. Costa-Nunes, V. V. Krishnan, J. M. Vohs and R. J. Gorte, Journal of the Electrochemical Society, 151 (2004) A604-A608.

"Fabrication of LSF-YSZ Composite Cathodes", Y. Huang, J. M. Vohs, and R. J. Gorte, Journal of the Electrochemical Society, 151 (2004) A646-A651.

"The Effect of Polarization on and Implications for Characterization of LSM-YSZ Composite Cathodes", S. McIntosh, S. B. Adler, J. M. Vohs, and R. J. Gorte, Electrochemical and Solid State Letters, 7 (2004) A111-A114.

"The Acylation of Propene by Acetic Acid over H-ZSM-5: The Role of Competitive Adsorption in Stability and Selectivity", O. Kresnawahjuesa, R. J. Gorte, and David White, Journal of Molecular Catalysis A, 212 (2004) 309-314.

"A Study of SOFC Anodes Based on Cu-Ni and Cu-Co Bimetallics", S.-I. Lee, J. M. Vohs, and R. J. Gorte, Journal of the Electrochemical Society, 151 (2004) A1319-A1323.

"Characterization of Sr-Doped LaCoO3-YSZ Composites Prepared by Impregnation Methods", Y. Huang, K. An, J. M. Vohs, and R. J. Gorte, Journal of the Electrochemical Society, 151 (2004) A1592-1597.

"Characterization of SO2-Poisoned Ceria-Zirconia Mixed Oxides", T. Luo and R. J. Gorte, Applied Catalysis B, 53 (2004) 77-85.

"Direct Hydrocarbon SOFC", S. McIntosh and R. J. Gorte, Chemical Reviews, 104 (2004) 4845-4865.

"A Comparison of Ceria and Sm-Doped Ceria for Hydrocarbon Oxidation Reactions", S. Zhao and R. J. Gorte, Applied Catalysis A, 227 (2004) 129-136.

"Recent Developments on Anodes for Direct Fuel Utilization in SOFC", R. J. Gorte, J. M. Vohs, and S. McIntosh, Solid State Ionics, 175 (2004) 1-6.

"Development of Intermediate-Temperature Solid Oxide Fuel Cells for Direct Utilization of Hydrocarbon Fuels", C. Lu, S. An, W. L. Worrell, J. M. Vohs, and R. J. Gorte, Solid State Ionics, 175 (2004) 47-50.

"Characterization of Cu-CeO2 direct hydrocarbon anodes in a solid oxide fuel cell with lanthanum gallate electrolyte", S. An, C. Lu, W. L. Worrell, R. J. Gorte, and J. M. Vohs, Solid State Ionics, 175 (2004) 135-138.

"Characterization of YSZ-YST Composites for SOFC Anodes", H. He, Y. Huang, J. M. Vohs, and R. J. Gorte, Solid State Ionics, 175 (2004) 171-176.


“Novel SOFC Anodes for the Direct Electrochemical Oxidation of Hydrocarbons”, R. J. Gorte and J. M. Vohs, Journal of Catalysis, 216 (2003) 477-486.

“The Role of Hydrocarbon Deposits in the Enhanced Performance of Direct-Oxidation SOFCs”, S. McIntosh, J. M. Vohs, and R. J. Gorte, Journal of the Electrochemical Society, 150 (2003) A470-476.

“Solid Oxide Fuel Cells for the Direct Oxidation of Hydrocarbon Fuels with Samaria Doped Ceria Electrolyte”, C. Lu, W. L. Worrell, R. J. Gorte, and J. M. Vohs, Journal of the Electrochemical Society, 150 (2003) A354-358.

“Synthesis of Highly Porous YSZ by Tape-Casting Methods”, M. Boaro, J. M. Vohs, R. J. Gorte, Journal of the American Ceramic Society, 86, (2003) 395-400.

"A Mechanistic Study of Sulfur Poisoning of the Water-Gas-Shift Reaction Over Pd/Ceria", T. Luo and R. J. Gorte, Catalysis Letters, 85 (2003) 139-146.

"Determining the Ce2O2S-CeOx phase boundary for conditions relevant to adsorption and catalysis", R. Ferrizz, R. J. Gorte, and J. M. Vohs, Applied Catalysis B, 43 (2003) 273-280.

"The Effect of Fe and Other Promoters on the Activity of Pd/Ceria for the Water-Gas Shift Reaction", X. Wang and R. J. Gorte, Applied Catalysis A, 247 (2003) 157-162.

"A Study of Direct-Oxidation SOFC with n-Butane at Higher Fuel Utilization", O. Costas-Nunes, J. M. Vohs, and R. J. Gorte, Journal of the Electrochemical Society, 150 (2003) A858-63.

"The Effect of Oxide Dopants in Ceria on n-Butane Oxidation", S. Zhao and R. J. Gorte, Applied Catalysis A, 248 (2003) 9-18.

"A Comparison of Cu-Ceria-SDC and Au-Ceria-SDC Composites for SOFC Anodes", C. Lu, W. L. Worrell, J. M. Vohs, and R. J. Gorte, Electrochemical Society Proceedings Volume 2003-07, 773-780; also, Journal of the Electrochemical Society, 150 (2003) A1357-A1359.

"Direct Oxidation as a Market Enabler for Solid-Oxide Fuel Cells", E. E. Paz, C. Wang, P. Palanisamy, R. J. Gorte, and J. M. Vohs, Electrochemical Society Proceedings Volume 2003-07, 787-792.

"Copper-Plated Stainless Steel for Bipolar Plates in Direct-Oxidation SOFC", S.-I. Lee, S. McIntosh, J. M. Vohs, and R. J. Gorte, Electrochemical Society Proceedings Volume 2003-07, 865-871.

"A Comparison of Cu-ceria-SDC and Au-ceria-SDC Composites for SOFC Anodes", C. Lu, W. L. Worrell, J. M. Vohs, and R. J. Gorte, Proceedings of the Electrochemical Society (2003) 773-780.

"Scandia stabilized zirconia (ScSZ) SOFCs for the direct oxidation of hydrocarbon fuels", S. An, C. Lu, W. L. Worrell, J. M. Vohs, and R. J. Gorte, Proceedings of the Electrochemical Society (2003) 66-72.

"A Study of Direct-Oxidation SOFC Anodes by Impedance Spectroscopy", S. McIntosh, J. M. Vohs, and R. J. Gorte, Journal of the Electrochemical Society, 150 (2003) A1305-1312.

"Effect of Precious-Metal Dopants on SOFC Anodes for Direct Utilization of Hydrocarbons", S. McIntosh, J. M. Vohs, and R. J. Gorte, Electrochemical and Solid State Letters, 6 (2003) A240-A243.

"Effect of Synthesis Conditions on the Performance of Cu-CeO2-YSZ Anodes in SOFC", H. He, J. M. Vohs, and R. J. Gorte, Journal of the Electrochemical Society, 150 (2003) A1470-75.

“Removal of Tetramethylammonium Cations from Zeolites at Low Temperatures”, O. Kresnawahjuesa, D. H. Olson, R. J. Gorte, and G. H. Kühl, Microporous and Mesoporous Materials, 51 (2002) 175-188.

“A Study of Steam Reforming of Hydrocarbon Fuels on Pd/ceria”, X. Wang and R. J. Gorte, Applied Catalysis A, 224 (2002) 209.

“SO2 Poisoning of Ceria-Supported, Metal Catalysts”, R. J. Gorte, and T. Luo, in "Catalysis by Ceria and Related Materials", A. Trovarelli, editor, Imperial College Press (2002) pp 377 - 389.

“Cu-Ni Cermet Anodes for Direct Oxidation of Methane in Solid-Oxide Fuel Cells”, H. Kim, C. Lu, W. L. Worrell, J. M. Vohs, and R. J. Gorte, Journal of the Electrochemical Society 149 (2002) A247-A250.

“Novel SOFC Anodes for the Direct Electrochemical Oxidation of Hydrocarbons, R. J. Gorte, H. Kim, and J. M. Vohs, Journal of Power Sources, 106 (2002) 10-15.

“Characterization of Solid Acids”, R. J. Gorte, in “Handbook on Porous Solids”, edited by F. Schuth, K. Sing, and J. Weitkamp, Willey, 2002, pp 432 - 460.

“Fabrication of Highly Porous YSZ by Acid Leaching Ni from a Ni-YSZ Cermet”, H. Kim, C. daRosa, M. Boaro, J. M. Vohs, and R. J. Gorte, Journal of the American Ceramic Society, 85 (2002) 1473-1476.

“Anode Development for Direct Oxidation of Hydrocarbons”, R. J. Gorte, Electrochemical Society, Proceedings Volume 2002-5, 60-71.

“Fabrication of SDC, Electrolyte-Supported ITSOFCs for Direct Oxidation of Hydrocarbon Fuels”, C. Lu, W. L. Worrell, J. M. Vohs, and R. J. Gorte, Electrochemical Society, Proceedings Volume 2002-5, 72-78.
Characterization of a Cu0.8Ni0.2-CeO2-YSZ Anode-Composite For the Direct Oxidation of Dry Methane”, C. Lu, W. L. Worrell, H. Kim, R. J. Gorte, J. M. Vohs, Electrochemical Society, Proceedings Volume 2002-5, 88-96.

“An Examination of Rare-Earth Additives on Performance of Cu-YSZ Cermet Anodes”, S. McIntosh, J. M. Vohs, and R. J. Gorte, Electrochimica Acta, 47 (2002) 3815-3821.

“An Examination of Bronsted-Acid Sites in H-[Fe]ZSM-5 for Olefin Oligomerization and Adsorption”, O. Kresnawahjuesa, G. H. Kuehl, R. J. Gorte, and C. A. Quierini, Journal of Catalysis, 210 (2002) 106-115.

“An Examination of Sulfur Poisoning on Pd/Ceria Catalysts”, T. Luo, J. M. Vohs, and R. J. Gorte, Journal of Catalysis, 210 (2002) 397-404.

“TPD and XPS Investigation of the Interaction of SO2 and Ceria”, R. M. Ferrizz, R. J. Gorte, and J. M. Vohs, Catalysis Letters, 82 (2002) 123-129.

“A Simple, Inexpensive, and Reliable Method for Measuring Brønsted-Acid Site Densities in Solid Acids”, O. Kresnawahjuesa, R. J. Gorte, D. de Oliveira, and L. Y. Lam, Catalysis Letters, 82 (2002) 155-160.

"Development of Solid Oxide Fuel Cells for the Direct Oxidation of Hydrocarbon Fuels", C. Lu, W. L. Worrell, C. Wang, S. Park, H. Kim, J. M. Vohs, and R. J. Gorte, Solid State Ionics, 152-153 (2002) 393-397.

“Deactivation Mechanisms for Pd/Ceria During the Water-Gas-Shift Reaction”, X. Wang, R. J. Gorte, and J. P. Wagner, Journal of Catalysis, 212 (2002) 225-230.


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William R. Graham

Undergraduate Chair and Professor of Materials Science and Engineering; Professor of Electrical and Systems Engineering
Email: wgraham at lrsm.upenn.edu
Personal Website

Research Interests:
Geometric, electronic, and vibrational structure and properties of surfaces and thin-film interface systems; medium-energy ion scattering, low-energy electron diffraction, Auger electron spectroscopy, molecular beam epitaxy, ultra-high-vacuum thin-film growth and characterization techniques.

Selected Recent Publications:
Andre, Paul Steven, Colgan, Evan George, Flake, John C., Fryer, Peter M., Graham, William, O'Sullivan, Eugene J. Formation of ohmic contact using self-doping layer for thin film transistor. Jpn. Kokai Tokkyo Koho, 2001,11 pp.

Sherman, W.B., Banerjee, R., DiNardo, N.J., Graham, W.R. RBS studies of the absolute coverage of Cs on the Si(111)-7*7 surface. Surface Science, v 479, n 1-3, 20 May 2001, p 136-40.


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David J. Graves

Associate Professor of Chemical and Biomolecular Engineering
Email: graves at seas.upenn.edu
Personal Website

Research Interests:
Bioproduct recovery from living cells, chemical conversions in living cells, DNA identification with immobilized hybridization.Bioproduct Recovery and Purification: Genetic engineering has recently captured public attention because of its potential for creating a limitless variety of biological materials. However, the commercialization of such products requires much more than just genetic manipulation and cloning of a cell which produces the product. The bioproduct must be recovered from a very dilute suspension, and separated from thousands of other similar molecules efficiently and inexpensively. We are studying several novel ways to recover such products selectively and continuously from fermentation broths or broken cell suspensions. One of the most promising techniques involves continuous adsorption in an unusual device called the magnetically stabilized fluidized bed (MSFB). The MSFB has significant advantages in productivity, simplicity, and freedom from clogging by debris over standard packed bed systems, and it can be much more efficient than fluidized systems. This work involves both ordinary ion exchange chromatography and a highly selective adsorption based on a biochemical "affinity" between the desired bio-molecule and a natural partner molecule (such as an antibody, receptor, inhibitor, etc.) in the MSFB. Eukaryotic Cell Technology: Although biochemical engineers have dealt successfully with bacterial and fungal cell cultures for many years, recent scientific work has shown that important products can be obtained from cultures of mammalian and plant cells. Thus, the unique engineering aspects of such delicate and complex systems are of great current interest. We are involved in several projects in this area. One involves studies on the adhesion of cells to each other and to surfaces. Although our studies are fundamental in orientation, they have relevance to cell separations, the metastasis of tumors, and cellular defense mechanisms. A second project is based on the use of the MSFB for the culture of isolated plant cells. This technology has considerable relevance to the growth of other cell types as well. Finally, studies are also underway on an important new anti-cancer drug which is found in an endangered species of yew. The challenge here is to grow cells of the endangered plant in the laboratory or to discover cost-effective ways to isolate the drug from more common species of this plant, in which it occurs at lower concentrations.

Selected Recent Publications:

Kajiyama, T., Miyahara, Y., Kricka, L. J., Wilding, P., Graves, D. J., Surrey, S., Fortina, P.,Genotyping on a Thermal Gradient DNA Chip," Genome Research 13, 467-475, 2003.

Milam, V.T.,Hiddessen, A.L., Crocker, J.C., Graves, D.J., and Hammer, D.A. DNA-driven Assembly of Bidisperse, Micron-sized Colloids," Langmuir, 19, 10317-10323, 2003.

Zhang, Y., Eniola, A.O., Graves, D.J., and Hammer, D.A. Specific Adhesion of Micron-Sized Colloids to Surfaces Mediated by Hybridizing DNA Chains. Langmuir, 19, 6905-6911, 2003.

Graves, D.J., Su, H.-J., Surrey, S., and Fortina, P. A Four-Laser Scanning Confocal System for Microarray Analysis BioTechniques, 32, #2 346-355 2002.

Su, H.J., Surrey, S., McKenzie, S.E., Fortina, P., and Graves, D.J. Kinetics of Heterogeneous Hybridization on Indium Tin Oxide Surfaces with and without an Applied Potential. Electrophoresis, 23, 1551-57, 2002.


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Roch Guerin

Professor of Electrical and Systems Engineering and Professor of Computer and Information Science (secondary appointment)
Email: Guerin at ee.upenn.edu
Personal Website

Research Interests:
Scalable QoS solutions. Routing and traffic engineering. "Robust networking", i.e., techniques that allow you to design networks and network mechanisms that can ensure efficient operation across a broad range of operational charactetistics. Wireless and ad-hoc networks.

Selected Recent Publications:

S. Tao, J. Apostolopoulos, and R. Guerin. Real-Time Monitoring of Video Quality in IP Networks. In Proceedings of ACM NOSSDAV’05, Skamania, OR, June 2005.

E. Vergetis, R. Guerin and S. Sarkar. Improving Performance Through Channel Diversity in the Presence of Bursty Losses. In Proceedings ITC-19, Beijing, China, August 2005.

Y. Huang and R. Guerin. Does Over-Provisioning Become More or Less Efficient as Networks Grow Larger? In Proceedings of ICNP 2005, Boston, MA, November 2005.

Y. Xu and R. Guerin. On the Robustness of Router-based Denial-of-Service (DoS) Systems. ACM Computer Communication Review, Vol. 35, No. 3, July 2005.

E. Vergetis, R. Guerin and S. Sarkar. Can Bluetooth Succeed as a Large-Scale Ad Hoc Networking Technology? IEEE J. Select. Areas. Commun., Special Issues on Wireless Ad-Hoc Networks, Vol 23, No. 5, March 2005.

A. Sridharan and R. Guerin. Making OSPF/IS-IS Routing Robust to Link Failures. In Proceedings of Networking’2005, University of Waterloo, Ontario, Canada, May 2005.

A. Sridharan, R. Guerin, and C. Diot, Achieving Near-Optimal Traffic Engineering Solutions for Current OSPF/IS-IS Networks. IEEE/ACM Trans. Netw. Vol 13, No. 2, April 2005.

Y. Xu and R. Guerin, Individual QoS Versus Aggregate QoS: A Loss Performance Study. IEEE/ACM Transactions on Networking, Vol. 13, No. 2, April 2005.

R. Sofia, R. Guerin, and P. Veiga. Enabling Scalable Inter-AS Signaling: A Load Reduction Approach. In Proceedings of IEEE ISCC’2005, La Manga del Mar Menor, Cartagena, Spain, June 27-30, 2005.

S. Tao, K. Xu, A. Estepa, T. Fei, L. Gao, R. Guerin, J. Kurose, D. Towsley, Z-L. Zhang. Improving VoIP Quality Through Path Switching. In Proceedings of IEEE INFOCOM’2005, Miami, Fl., March 2005.

S. Tao, K. Xu, Y. Xu, T. Fei, L. Gao, R. Guerin, J. Kurose, D. Towsley, Z-L. Zhang. Exploring the Performance Benefits of End-to-End Path Switching. In Proceedings of IEEE ICNP 2004, Berlin, Germany, Oct, 2004.

S. Tao and R. Guerin. Application-Specific Path Switching: A Case Study for Streaming Video. In Proceedings of ACM Multimedia 2004, October 10-16 2004, New York, NY.

S. Tao and R. Guerin, On-line Estimation of Internet Path Performance: An ApplicationPerspective. In Proceedings of IEEE INFOCOM’2004, Hong Kong, March 2004.

Y. Huang and R. Guerin, A Simple FIFO-Based Scheme for Differentiated Loss Guarantees.In Proceedings of The Twelfth IEEE International Workshop on Quality of Service (IWQoS2004), June 7-9, 2004, Montreal, Canada.

R. Guerin, J. Rank, S. Sarkar, and E. Vergetis, Forming Connected Topologies in Bluetooth Ad-hoc Networks - An Algorithmic Perspective. In Proceedings of ITC’18, Berlin, Germany, September 2003.

Y. Huang, R. Guerin, and P. Gupta, Supporting Excess Real-Time Traffic with Active Drop Queue. In Proceedings of ITC’18, Berlin, Germany, September 2003.

R. Sofia, R. Guerin, and P. Veiga, SICAP: A Shared-segment Inter-domain Control Aggregation
Protocol. In Proceedings of HPSR’2003, Torino, Italy, June 2003.

R. Sofia, R. Guerin and P. Veiga. A Shared-segment Inter-domain Control Aggregation Protocol. In Proceedings of HPSR’2003, Torino, Italy, June 2003.

A. Sridharan, R. Guerin, and C. Diot, Achieving Near-Optimal Traffic Engineering Solutionsfor Current OSPF/IS-IS Networks. In Proceedings of IEEE INFOCOM’2003, San Francisco,CA, March 2003.

Y. Xu and R. Guerin. On Evaluating Loss Performance Deviation: A Simple Tool and ItsPractical Implications. In Proceedings of the 2nd International Workshop on QoS in Multiservice IP Networks (QoS-IP 2003), Milano, Italy, February 2003.

X.Lu, S. Tao, M. El Zarki, and R. Guerin, Quality-based Adaptive Video Over the Internet.In Proceedings of CNDS’2003, Orlando, FL, January 2003.

R. Sofia, R. Guerin, and P. Veiga, An Investigation of Inter-Domain Control AggregationProcedures. In Proceedings of ICNP’2002, Paris, France, November 2002.

R. Guerin and A. Orda. Computing Shortest Paths for Any Number of Hops. IEEE/ACM Transactions on Networking, Vol. 10, No. 5, pp. 613-620, October 2002.

M. Goyal, R. Guerin, and R. Rajan, Predicting TCP Throughput From Non-invasive Data.In Proceedings of INFOCOM’2002, New York, NY, June 2002.

Y. Xu and R. Guerin, Individual QoS versus aggregate QoS: A loss performance study. In Proceedings of INFOCOM’2002, New York, NY, June 2002).

R. Guerin, E. Kim and S. Sarkar. Bluetooth Technology: Key Challenges and Initial Research. In Proceedings of the 2002 Conference on Network and Distributed Simulations(CNDS’2002), San Antonio, TX, January 2002.


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Sudipto Guha

Assistant Professor of Computer and Information Science and Class of 1965 Computer and Information Science Term Assistant Professor
Email: sudipto at seas.upenn.edu
Personal Website

Research Interests:
Design and analysis of algorithms for computation under constrained resources, graph approximation algorithms for NP-hard problems, single pass data stream algorithms, efficient optimization in database query and mining, randomized algorithms and combinatorial optimization.

Selected Recent Publications:
M. Charikar and S. Guha. Improved combinatorial algorithms for facility location problems. SIAM Journal on Computing 34 (4): 803-824 2005.

Y. Azar, A., Buchsbaum, B. Chazelle, et al. Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms: Preface, 2005, p xiii.

T. Batu, S. Guha and S. Kannan. Inferring mixtures of Markov chains. Lecture Notes in Artificial Intelligence, v 3120, Learning Theory, 2004, p 186-199.

J. Chuzhoy, S. Guha, E. Halperin, J. Naor, S. Khanna, G. Kortsatz. Asymmetric k-center is O(log n) hard to approximate. Proceedings of the 36th ACM Symposium on Theory of Computing, 2004, P 21-27.

J. Chuzhoy, S. Guha,S. Khanna,S. Naor. Machine Minimization for Scheduling jobs with Interval Constraints. Proceedings of Foundations of Computer Science (FOCS), 2004, p 81-90.

S. Guha, K. Shim, J. Woo. REHIST: Relative Error Histogram Construction Algorithm. Proceedings of International conference on Very Large DataBases (VLDB), 2004.

S.Guha, N. Koudas, A. Marathe and D. Srivastava. Merging the Results of Approximate Match operations. Proceedings of International conference on Very Large DataBases (VLDB), 2004, p 636-647.

S. Guha, C. Kim, K. Shim. XWAVE: Approximate Extended Wavelets for Streaming Data. Proceedings of International conference on Very Large DataBases (VLDB), 2004.

R. Alur, S. Chaudhuri, K. Etessami, S. Guha, and M. Yannakakis Compression of Partially Ordered Strings. Proceedings of International Conference on Concurrency Theory (CONCUR), pp 42-56, 2003.

C. Chekuri, S. Guha, and J. Naor. Approximate Steiner K Cuts. Proceedings of International Colloquim on Automata, Languages and Processing (ICALP), pp 188-199, 2003.

J. Chuzhoy, S. Guha, E. Halperin, J. Naor, S. Khanna, G. Kortsatz, R. Krauthgamer.
Asymmetric k-center is O(log n) hard to approximate. Electronic Colloquium in Computational Complexity, Reports (037) and (038), 2003.

G. Even, S. Guha and B. Schieber. Improved Approximations of Crossings in Graph Drawings and VLSI layout areas. SIAM Journal of Computing, v32(1), pp 231-252, 2003.

S. Guha, D. Gunopulous, N. Koudas. Correlating Synchronous and Asynchronous Data Streams. to appear in Proceedings of ACM-SIGKDD International
conference on Knowledge Discovery and Data Mining, pp 539-534, 2003.

S. Guha, D. Gunopulous, N. Koudas, D. Srivastava, and M. Vlachos. Efficient Approximation of Optimization Queries Under Parametric Aggregation Constraints. Proceedings of International conference on Very Large DataBases (VLDB), pp 778-789, 2003.

S. Guha, R. Hassin, S. Khuller, and E. Or. Capacitated Vertex Cover with Applications. Journal of Algorithms, special issue on 12th ACM SODA, v48(1), pp 257-270, 2003.

S. Guha, S. Krishnan, K. Munagala, and S. Venkatasubramanian. Applications of two sided depth test to CSG rendering in Proceedings of ACM-I3D Symposium on Interactive 3D graphics, 2003.

S. Guha, N. Koudas, D. Srivastava, and T. Yu. Index Based Approximate XML Joins. Proceedings of International Conference in Data Engineering (ICDE), pp 708-711, 2003.

S. Guha, A. Markopoulou, F. A. Tobagi. Hierarchical Reliable Multicast: Performance Analysis and Optimal Placement of Proxies. Computer Communications 26(18), 2070-2081, 2003.

S. Guha, A. Meyerson, N. Mishra, R. Motwani, and L. O'callaghan. Clustering Data Streams: Theory and Practice. TKDE Special issue on Streaming v15(3), pp 515-529, 2003.

S. Guha, A. Meyerson, and K. Munagala. A Constant Factor Approximation Algorithm for the Fault-Tolerant Facility Location Problem. Journal of Algorithms, v48(2), pp 429-440, 2003.

A. Bar-noy, S. Guha, Y. Katz, J. Naor, B. Schieber and H. Sachnai, Throughput Maximization of Real-Time Scheduling with Batching. Proceedings of ACM-SIAM Symposium on Discrete Algorithms (SODA), pp 742-751, 2002.

M. Charikar, S. Guha, E. Tardos and D. Shmoys. A Constant factor Approximation for the K median Problem. Invited to special (STOC 1999) issue of Journal of Computer and System Sciences, v65(1), pp 129-149, 2002.

A. C. Gilbert, S. Guha, P. Indyk, Y. Kotidis, S. Muthukrishnan and M. J. Strauss. Fast Small-space Algorithms for Approximate Histogram Maintenance. Proceedings of ACM-STOC Symposium on Theory of Computing, pp 389-398, 2002.

A. C. Gilbert, S. Guha, P. Indyk, S. Muthukrishnan and M. J. Strauss. Near-Optimal Sparse Fourier Representations via Sampling. Proceedings of ACM-STOC Symposium on Theory of Computing, pp 152-161, 2002.

S. Guha, R. Hassin S. Khuller and E. Or. Capacitated Vertex Covering with Applications. Proceedings of ACM-SIAM Symposium on Discrete Algorithms (SODA), pp 858-865, 2002.

S. Guha, P. Indyk, S. Muthukrishnan and M. J. Strauss. Histogramming Data Streams with Fast per Item Processing in Proceedings of International Colloquim on Automata. Languages and Processing (ICALP), pp 681-692, 2002.

S. Guha, H. Jagadish, N. Koudas, D. Srivastava, and T. Yu, Approximate XML Joins. Proceedings of ACM-SIGMOD International Conference on Management of Data, pp 287-298, 2002.

S. Guha and N. Koudas. Approximating a Data Stream for Querying and Estimation: Algorithms and Performance. Proceedings of International Conference in Data Engineering (ICDE), pp 567-576, 2002.

S.Guha, N. Koudas, and D. Srivastava. Fast Algorithms For Hierarchical Range Histogram Construction. Proceedings of ACM-PODS Principles of Database Systems, 180-187, 2002.

S. Guha and K. Munagala. Generalized Clustering. Proceedings of ACM-SIAM Symposium on Discrete Algorithms (SODA), pp 484-485, 2002.

S. Guha and K. Munagala. Improved Algorithms for the Data Placement Problem. Proceedings of ACM-SIAM Symposium on Discrete Algorithms (SODA), pp 106-107, 2002.

L. O'Callaghan, N. Mishra, A. Meyerson, S. Guha and R. Motwani. Streaming Data-Algorithms for High Quality Clustering. Proceedings of International Conference in Data Engineering (ICDE), pp 685-695, 2002.

N. Thaper, S. Guha, P. Indyk, and N. Koudas. Dynamic Multidimensional Histograms in Proceedings of ACM-SIGMOD International Conference on Management of Data, pp 428-439, 2002.


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Daniel A. Hammer

Alfred G. and Meta A. Ennis Professor of Bioengineering, Chairman, Department of Bioengineering; Professor, Chemical and Biomolecular Engineering; and Member, Institute for Medicine and Engineering
Email: hammer at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Understanding and manipulating the behavior of biological systems, biophysics of cell adhesion, virus-cell interactions, soft-bio materials. Our work on cell adhesion is aimed at understanding how the dynamics and strength of cell adhesion is controlled by the physical and chemical properties of cell surface molecules. We use several tools to pursue this relationship. First, we alter the chemistry of adhesion molecules systematically and measure the resulting affect on adhesion in carefully constructed assays. Second, we have developed "cell-free" adhesion assays in which we measure the dynamics of adhesion when adhesion molecules are attached to beads and inert substrata, thus focusing unambiguously on the role of surface adhesion molecules in controlling adhesion. Third, in collaboration with Dr. Rick Waugh (University of Rochester) we have built a calibrated microcantilever to measure the strength of adhesion of individual adhesive bonds. And finally, we have developed a computer algorithm, "adhesive dynamics", in which we can simulate the adhesion of cells to surfaces. This algorithm represents a wonderful tool to test systematically the relationship between adhesion molecule properties and cell adhesion in ways that are not feasible experimentally. Our efforts in cell adhesion research have led to a number of fundamental insights. We have been the first lab to recreate "rolling" - the slow translation of white blood cells over blood vessel walls - in a cell free system. In collaboration with Dr. Tim Springer (Harvard), we were the first to measure the relationship between force and bond dissociation for a bioadhesion molecule. Also, we were the first lab to calculate the complete phase diagram of adhesion, relating adhesion molecule properties to the dynamics of adhesion. Virus-cell interactions: Viruses are fascinating, compact biological packages whose sole goal is to infect host cells. Not only do viruses cause disease, but they can also be used to introduce missing genes into cells (gene therapy). Our lab is focused on the fundamental factors that control viral infection, with a long term goal to increase the efficiency of infection (for gene therapy) or block infection (in viral mediated disease). A step in the viral infection cascade is membrane fusion, where the outer lipid bilayer of the virus fuses with a membrane of the host cells. The coalescence of these two membranes allows the genetic material of the virus to enter the host cell nucleus. This fusion is mediated by proteins on the viral surface, which are designed to cause membrane coalescence, often at low pH. We have been interested in the mechanism of fusion, and how it is controlled by the physical chemistry of the viral adhesion molecules and the lipid chemistry of the cell membranes. Our long-term goal is to reconstitute the fusion activity of viral molecules into larger structures, such as vesicles and cells, and to measure the mechanics and dynamics of fusion using micropipette.

Selected Recent Publications:
Zhang Y, Hammer DA, Graves DJ. Competitive Hybridization Kinetics Reveals Unexpected Behavior Patterns Biophys J. 2005 Aug 26.

Sarratt, KL; Chen, H; Zutter, MM; Santoro, SA; Hammer, DA; Kahn, ML. Aggregate formation to collagen under flow. BLOOD, 106 (4): 1268-1277 AUG 15 2005.

Lin, J.J.; Bates, F.S.; Hammer, D.A.; Silas, J.A.. Adhesion of polymer vesicles. Physical Review Letters, v 95, n 2, 8 July 2005, p 026101/1-4.

Eniola, AO; Hammer, DA. In vitro characterization of leukocyte mimetic for targeting therapeutics to the endothelium using two receptors.

BIOMATERIALS, 26 (34): 7136-7144 DEC 2005

Biophys J. 2005 Aug 12; [Epub ahead of print]
I-Domain of Lymphocyte Function-Associated Antigen-1 (LFA-1) Mediates Rolling of
Polystyrene Particles on ICAM-1 under Flow.
Hammer DA, Eniola AO, Krasik E, Smith L, Song G.

Willcox, P.J., Reinhart-King, C.A., Lahr, S. J., Degrado, W.F. and Hammer, D.A. Dynamic heterodimer-functionalized surfaces for endothelial cell adhesion. Biomaterials, v 26, n 23, August 2005 p 4757-4766.

Caputo, K.E. and Hammer, D.A. Effect of microvillus deformability on leukocyte adhesion explored using adhesive dynamics simulations. Biophysical Journal, 89(1), 187-200, July 2005.

Reinhart-King C.A., Dembo, M., and Hammer D.A. The dynamics and mechanics of endothelial cell spreading. Biophysical Journal, 89(1), 676-689, July 2005.

King, M.R., Henrich V., Evnas, E. and Hammer D.A. Nano-to-micro scale dynamics of P-selectin detachment from leukocyte interfaces. III. Numerical simulation of tethering under flow. Biophysical Journal, 88(3): 1676-83, March 2005.

English T.J. and Hammer, D.A. The effect of cellular receptor diffusion on receptor-mediated viral binding using Brownian adhesive dynames (BRAD) simulations. Biophysical Journal, 88(3), 1666-75, March 2005.

Ghoroghchian P.P., Frail P.R., Susumu, K., Blessington, D. Brannan, A.K., Bates F.S., Chance B., Hammer, D.A. and Therien, M.J. Near infrared-emissive polymersomes: self-assembled soft matter for in vivo optical imaging. Proceedings of the National Academy of Sciences of the United States of America, 102(8), 2922-7, February 22, 2005.

Hammer, D.A. Leukocyte adhesion. What’s the catch? Current Biology, 15(3): R96-9, February 8 2005.

Eniola, A.O. and Hammer, D.A. Characterizatio of biodegradable drug delivery vehicles with the adhesive properties of leukocytes II: Effect of degradation on targeting activity. Biomaterials, v 25, n 6, February 2005, p 661-670.

Aranda-Espinoza, H., Dembo, M., and Hammer, D.A. The traction stresses of neutrophils during adhesion and chemokinesis. Biophysical Journal, 88(1), 540A-540A Part 2 Suppl. S Jan 2005.

Im, J.H., Fu, W., Wang, H., Bhatia, S.K., Hammer, D.A., Kowalska, M.A., and Muschel, R.J. Coagulation facilitates tumor cell spreading in the pulmonary vasculature during early metastatic colony formation. Cancer Research, 64(23), 8613-9, December 1 2004.

Reinhart-King, C.A., Dembo, M., and Hammer D.A. Endothelial cell spreading dynamics. Molecular Biology of the Cell 15, 174A-174A 964 Supp., November 2004.

Paszek, M.J., Zahir, N., Lakins, J.N. et al. Mechano-signaling in mammary morphogenesis and tumorigenesis. Molecular Biology of the Cell 15: 241A-241A 1329 Suppl, November 2004.

Krasik, E.F., and Hammer, D.A. A semianalytic model of leukocyte rolling. Biophysical Journal, 87(5): 2919-30, November 2004.

Hiddesse, A.L., Weitz, D.A., and Hammer D.A. Rheology of binary colloidal structures assembled via specific biological cross-linking. Langmuir, v 20, n 16, Aug 3 2004, p 6788-6795.

Sarratt, K.L., Chen, H., Kahn, M.L., and Hammer, D.A. Platelet receptor glycoprotein VI-mediated adhesion to type I collage under hydrodynamic flow. Annals of Biomedical Engineering, v32, n 7, July 2004, p 970-976.

Lin, J.H., Silas, J.A., Bermudez, H., Milam, V.T., Bates, F.S., and Hammer, D.A. The effect of polymer chain length and surface density on the adhesiveness of functionalized polymersomes. Langmuir, v 20, n 13, Jun 22 2004, p 5493-5500.

T.J. English and D.A. Hammer, "Detailed analysis of the equivalent site hypothesis for receptor-medicated viral binding using Brownian Adhesive Dynamics (BRAD) simulations," Biophy. J. 86, 3359 (2004).

Bermudez, H., Hammer, D.A., Discher, D.E. Effect of bilayer thickness on membrane bending rigidity. Langmuir, v 20, n 3, Feb 3, 2004, p 540-543.

Lau, W.L., Ege, D.S., Lear J.D., Hammer D.A., and DeGrado, W.F. Oligomerization of fusogenic peptides promotes membrane fusion by enhancing membrane destabilization. Biophysical Journal, 86(1 Pt 1), 272-84, January 2004.

Milam, Valeria T. , Hiddessen, Amy L., Crocker, John C., Graves, David J., Hammer, Daniel A. DNA-Driven Assembly of Bidisperse, Micron-Sized Colloids. Langmuir, v 19, n 24, Nov 25, 2003, p 10317-10323.

Bermudez, H., Aranda-Espinoza, H., Hammer, D.A., Discher, D.E. Pore stability and dynamics in polymer membranes. Europhysics Letters, v 64, n 4, 15 Nov. 2003, p 550-6.

Bhatia, S.K., Hammer, D.A. The shear threshold effect for particle adhesion to bioreactive surfaces: influence of receptor and ligand site density. Proceedings of the IEEE 29th Annual Northeast Bioengineering Conference (Cat. No.03CH37433), 2003, p 187-8.

Bhatia, S.K., Hammer, D.A. Dynamic simulations of inflammatory cell recruitment: the state diagram for cell adhesion mediated by two receptors. Proceedings of the IEEE 29th Annual Northeast Bioengineering Conference (Cat. No.03CH37433), 2003, p 158-9.

English, T.J., Hammer, D.A. HIV viral docking: model predictions for bond number and trajectory. Proceedings of the IEEE 29th Annual Northeast Bioengineering Conference (Cat. No.03CH37433), 2003, p 156-7.

Eniola, A.O., Willcox, P.J., Hammer, D.A. Interplay between rolling and firm adhesion elucidated with a cell-free system engineered with two distinct receptor-ligand pairs. Biophysical Journal, v 85, n 4, Oct. 2003, p 2720-31.

Zhang, Ying, Eniola, A. Omolola, Graves, David J., Hammer, Daniel A. Specific adhesion of micron-sized colloids to surfaces mediated by hybridizing DNA chains. Langmuir, v 19, n 17, Aug 19, 2003, p 6905-6911.

King MR. Hammer DA. Hydrodynamic recruitment of rolling leukocytes in vitro. Biophysical Journal. 84(6):4182, author reply 4183, 2003 Jun.

Bhatia, Sujata K., Swers, Jeffrey S., Camphausen, Raymond T., Wittrup, K. Dane, Hammer, Daniel A. Rolling adhesion kinematics of yeast engineered to express selectins. Biotechnology Progress, v 19, n 3, May/June, 2003, p 1033-1037.

Bhatia, S.K. , King, M.R., Hammer, D.A. The state diagram for cell adhesion mediated by two receptors. Biophysical Journal, v 84, n 4, April 2003, p 2671-90.

Reinhart-King, Cynthia A., Dembo, Micah, Hammer, Daniel A. Endothelial cell traction forces on RGD-derivatized polyacrylamide substrata Langmuir, v 19, n 5, Mar 4, 2003, p 1573-1579.
Bermudez, Harry, Brannan, Aaron K., Hammer, Daniel A., Bates, Frank S., Discher, Dennis E. Molecular weight dependence of polymersome membrane structure, elasticity, and stability. Macromolecules, v 35, n 21, Oct 8, 2002, p 8203-8208.

Bhatia, Sujata K., Hammer, Daniel A. Influence of receptor and ligand density on the shear threshold effect for carbohydrate-coated particles on L-selectin. Langmuir, v 18, n 15, Jul 23, 2002, p 5881-5885.

Bhatia, S.K., Hammer, D.A. The shear threshold effect for adhesion through L-selectin: influence of receptor and ligand site density. Conference Proceedings. Second Joint EMBS-BMES Conference 2002. 24th Annual International Conference of the Engineering in Medicine and Biology Society. Annual Fall Meeting of the Biomedical Engineering Society (Cat. No.02CH37392), 2002, pt. 1, p 647-8 vol.1.

Bhatia, S.K., Swers, J.S., Camphausen, R.T., Wittrup, K.D., Hammer, D.A. Rolling adhesion of yeast engineered to express cell adhesion molecules. Proceedings of the IEEE 28th Annual Northeast Bioengineering Conference (IEEE Cat. No.02CH37342), 2002, p 115-16.

Bhatia, S.K. , Swers, J.S., Capmhausen, R.T., Wittrup, K.D., Hammer, D.A. Yeast surface display of cell adhesion molecules: a tool for molecular evolution and cellular motion characterization. Conference Proceedings. Second Joint EMBS-BMES Conference 2002. 24th Annual International Conference of the Engineering in Medicine and Biology Society. Annual Fall Meeting of the Biomedical Engineering Society (Cat. No.02CH37392), 2002, pt. 1, p 732-3 vol.1.

Discher, B.M., Bermudez, H., Hammer, D.A., Discher, D.E., You-Yeon Won, Bates, F.S. Cross-linked polymersome membranes: Vesicles with broadly adjustable properties. Journal of Physical Chemistry B, v 106, n 11, 21 March 2002, p 2848-54.

Eniola, A.O., Hammer, D.A. Biodegradable artificial leukocyte for targeted drug delivery. Conference Proceedings. Second Joint EMBS-BMES Conference 2002. 24th Annual International Conference of the Engineering in Medicine and Biology Society. Annual Fall Meeting of the Biomedical Engineering Society (Cat. No.02CH37392), 2002, pt. 1, p 521-3 vol.1.

Eniola, A. Omolola, Rodgers, Stephen D., Hammer, Daniel A. Characterization of biodegradable drug delivery vehicles with the adhesive properties of leukocytes. Biomaterials, v 23, n 10, 2002, p 2167-2177.

Sarratt, K.L., Chen, H.M., Kahn, M.L., Hammer, D.A. Effect of shear stress on platelet activation via the glycoprotein VI receptor. Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, v 1, 2002, p 674-675.

Tees, David F. J., Chang, Kai-Chien, Rodgers, Stephen D., Hammer, Daniel A. Simulation of cell adhesion to bioreactive surfaces in shear: The effect of cell size. Industrial and Engineering Chemistry Research, v 41, n 3, Feb 6, 2002, p 486-493.


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Howard H. Hu

Associate Professor of Mechanical Engineering and Applied Mechanics
Email: hhu at seas.upenn.edu
Personal Website

Research Interests:
Computational Fluid Dynamics: The goal is to develop high-performance software packages capable of simulating the motion of thousands of dispersed rigid and deformable particles in fluids. The computational schemes use a special finite element method, and the computation is performed on an unstructured body-fitted grid with an arbitrary Lagrangian-Eulerian moving mesh technique. Modeling Complex Flows Involving Multiphase and Polymeric Fluids: This project is to simulate the motion of a large number of solid particles in both Newtonian fluids, governed by the Navier-Stokes equations, and in various models of viscoelastic fluids. The goal is to elucidate the fundamental dynamics of particulate flows and solve problems in mechanical, chemical and petroleum engineering, food processing, biological and medical applications. Fluid Surface/Interface Instability: The project is to numerically analyze the hydrodynamic instability of the interface between two fluids, and to develop tools for diagnosing physical mechanisms of the instabilities. It has practical applications, for example, in the water-lubricated transport of highly viscous materials through pipelines.

Selected Recent Publications:

Hu, H.H. and Wang K.H. Damping effect on waves propagating past a submerged horizontal plate and a vertical porous wall. Journal of Engineering Mechanics, ASCE 131(4), 427-437, April 2005.

Mukundakrishnan K., Ayyaswamy P.S., Risbud, M., Hu, H.H., and Shapiro I.M. Modeling of phosphate ion transfer to the surface of osteoblasts under normal gravity and simulated microgravity conditions. Annals of the New York Academy of Sciences 1027, 85-98, November 2004.

Swaminathan, T.N., Hu, Howard H. Particle interactions in electrophoresis due to inertia. Journal of Colloid and Interface Science, v 273, n 1, May 1, 2004, p 324-330.

Hui Liu, Bau, H.H., Hu, H. On the translation of a cylinder in a long tube. Physics of Fluids, v 16, n 4, April 2004, p 998-1007.

Liu, Hui, Bau, Haim H., Hu, Howard H. Electrophoresis of concentrically and eccentrically positioned cylindrical particles in a long tube. Langmuir, v 20, n 7, Mar 30, 2004, p 2628-2639.

Gan, H., Chang, J., Feng, J. J. & Hu, H. H. Direct numerical simulation of the sedimentation of solid particles with thermal convection. J. Fluid Mech. 481, 385-411, 2003.

Gan, H., Feng, J. J. & Hu, H. H. Simulation of the sedimentation of melting solid particles. Int. J. Multiphase Flow. 29(5), 751-769, 2003.

N. Patankar and H.H. Hu. Finite Reynolds Number Effect on the Rheology of a Suspension of Neutrally Buoyant Solid Bodies in a Newtonian Fluid. International Journal of Multiphase Flow28, 409-425, 2002.

Yi, M., Bau, H.H., Hu, H. Peristaltically induced motion in a closed cavity with two vibrating walls. Physics of Fluids, v 14, n 1, January, 2002, p 184-197.


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Zachary G. Ives

Assistant Professor of Computer and Information Science; Associated Faculty, Penn Center for Bioinformatics
Email: zives at cis.upenn.edu
Personal Website

Research Interests:
My research interests generally lie in the areas of databases and distributed systems, especially as they relate to the Web and to Web-scale information sharing. I have two main research directions here at Penn.

The first project is a system called Orchestra, which focuses on the problem of collaborative data sharing. Here, we have a loose confederation of databases or data warehouses in which the members want to share information (even though they have different schemas). Moreover, each site is independently updating the contents of its database, often making corrections and amendments. The major challenge is how to -- in a peer-to-peer like system with no central control -- propagate the updates from one participant to another and allow each site to override updates from elsewhere. Our goal is to support environments in which the local participant has complete control of his or her data and schema, but can import data from elsewhere in a "managed" fashion. Within this context, we are studying a number of problems relating to update translation and propagation, peer-to-peer system architectures, distributed update translation, and distributed query processing. This project is funded by an NSF CAREER award, and it builds upon components developed for the Tukwila and Piazza systems.

My second major project, in collaboration with Prof. Insup Lee, focuses on the problem of programming large-scale and complex sensor networks. The Aspenn system focuses on a setting in which large numbers of distributed sensors, with varying capabilities, must be coordinated in order to manage and reason about collections of physical entities and phenomena.

Selected Recent Publications:

Zachary Ives, Madhukar Anand, and Insup Lee. Quantifying Eavesdropping Vulnerability in Sensor Networks. VLDB Workshop on Data Management for Sensor Networks, August 2005.

Zachary Ives, Alon Halevy, Peter Mork, and Igor Tatarinov. Mediation of Semantic Web Data in Piazza. Book Chaper, Semantic Web and Peer-to-Peer: Opportunities and Challenges.

Zachary Ives, Alon Halevy, Dan Suciu, and Igor Tatarinov. Schema Mediation for Large-Scale Data Sharing. VLDB Journal Vol 14 No 1 March 2005.

Zachary Ives, Nitin Khandelwal, Aneesh Kapur, and Murat Cakir. ORCHESTRA: Rapid Collaborative Sharing of Dynamic Data. CIDR, January 2005, Asilomar CA.

Zachary Ives, Alon Y. Halevy, Daniel S. Weld. Adapting to Source Properties in Processing Data Integration Queries. ACM SIGMOD Conference on Management of Data, June 2004, Paris, France.

Zachary Ives, Alon Halevy, Peter Mork, Igor Tatarinov. Piazza: Mediation and Integration Infrastructure for Semantic Web Data. Journal of Web Semantics, Vol. 1 No. 2, February 2004, 155-175.

Zachary Ives, Alon Halevy, Jayant Madhavan, Peter Mork, Dan Suciu, and Igor Tatarinov. The Piazza Peer Data Management System. IEEE Transactions on Knowledge and Data Engineering, Vol 16 No. 7, July 2004, 787-798.

Igor Tatarinov, Zachary Ives, Jayant Madhavan, Alon Halevy, Dan Suciu, Nilesh Dalvi, Xin (Luna) Dong, Yana Kadiyska, Peter Mork. The Piazza Peer Data Management Project. SIGMOD Record, Vol 32(3), September, 2003.

Alon Halevy, Zachary Ives, Peter Mork, Igor Tatarinov. Piazza: Data Management Infrastructure for Semantic Web Applications. Twelfth World Wide Web Conference, May 2003.

Alon Y. Halevy, Zachary G. Ives, Dan Suciu, Igor Tatarinov. Schema Mediation in Peer Data Management Systems. International Conference on Data Engineering, March 2003.

Oren Etzioni, Alon Halevy, AnHai Doan, Zachary Ives, Jayant Madhavan, Luke McDowell, Igor Tatarinov. Crossing the Structure Chasm. Conference on Innovative Database Systems Research (CIDR), January 2003.

Zachary G. Ives, Alon Y. Halevy, Daniel S. Weld. An XML Query Engine for Network-Bound Data. VLDB Journal, Vol. 11 No. 4.


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Ali Jadbabaie

Assistant Professor of Electrical and Systems Engineering
Email: jadbabai at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Optimization-based, dynamically reconfigurable control with applications to Unmanned Aerial Vehicles (UAVs); Distributed coordination and control of multi-agent systems; Robust control of Linear Parameter Varying (LPV) systems; Graph theory, theory of non-negative matrices and Markov chains

Selected Recent Publications:
N. Moshtagh, A. Jadbabaie, and K. Daniilidis. Vison-based distributed coordination of mutliagent systems. First Workshop on Robotics Science and Systems, Cambridge, MA, June 2005.

N. Moshtagh, A. Jadbabaie, and K. Daniilidis. Distributed geodesic control laws for flocking of nonholonomic agents. ECC-CDC 2005, Seville, Spain.

A. Ahmadzadeh, A. Halasz, S. Prajna, A. Jadbabaie, and V. Kumar. Analysis of the Lactose metabolism in E. coli using sum-of-squares decomposition. ECC-CDC 2005, Seville, Spain.

Papachristodoulou and A. Jadbabaie. Synchronization in Oscillator Networks: Switching topologies and presence of nonhomogeneous delays. ECC-CDC 2005, Seville, Spain.

S. Prajna and A. Jadbabaie. Methods for Safety verification of time delay systems. ECC-CDC 2005, Seville, Spain.

S. Prajna, A. Jadbabaie, and G.J. Pappas. A Framework for Worst-Case and Stochastic Safety Verification Using Barrier Certifciates. IEEE Transactions on Automatic Control, March 2005.

H. Tanner, A. Jadbabaie, and G.J. Pappas. Flocking in fixed and switching networks. IEEE Transaction on Automatic Control, March 2005.

A. Jadbabaie and J. Hauser. On the stability of receding horizon control with a general terminal cost. IEEE Transactions on Automatic Control, May 2005.

A. Jadbabaie, N. Motee, and M. Barahona. On the stability of the Kuramoto model of coupled nonlinear oscillators. American Control Conference (ACC 2004).

S. Prajna and A. Jadbabaie. Saftey verification of hybrid systems using barrier certificates. Hybrid Systems: Computation and Control, Springer Lecture Notes in Computer Science, March 2004.

A. Jadbabaie. On geographic routing without location information. IEEE Conference on Decision and Control, The Bahamas, 2004.

J-S. Kim, T-W. Yoon, A. Jadbabaie, and C. De Persis. Input-to-state stabilizing MPC for neutrally stable linear systems subject to input constraints. IEEE Conference on Decision and Control, p 5041-6, 2004.

H. Tanner, A. Jadbabaie, and G. J. Pappas. Stable flocking of mobile agents, Part I: Fixed Topology. IEEE Conference on Decision and Control, Maui, HI, December 2003.

H. Tanner, A. Jadbabaie, and G. J. Pappas. Stable flocking of mobile agents, Part II: Dynamic Topology. IEEE Conference on Decision and Control, Maui, HI, December 2003.

H. Tanner, A. Jadbabaie, and G. J. Pappas. Flocking in fixed and switching networks. Submitted to Automatica, July 2003.

A. Jadbabaie. On coordination strategies for mobile agents with changing nearest neighbor sets. IEEE Mediterranian Conference on Control and Automation, Rhodes, Greece, June 2003.

A. Jadbabaie, J. Lin, and A. S. Morse. Coordination of groups of mobile autonomous agents using nearest neighbor rules. IEEE Transactions on Automatic Control, Vol. 48, No. 6, June 2003, pp. 988-1001.

H. Tanner, A. Jadbabaie, and G. J. Pappas. Coordination of multiple autonomous vehicles IEEE Mediterranian Conference on Control and Automation, Rhodes, Greece, June 2003.

A. Jadbabaie, C. Depersis, and T.W. Yoon A globally stabilizing receding horizon controller for neutrally stable linear systems with input constraints. IEEE Conference onDecisiona nd Control, Las Vegas, NV, 2002.

A. Jadbabaie and J. Hauser. Control of a thrust-vectored flying wing: A receding horizon/LPV approach. International Journal of Robust and Nonlinear Control, Vol. 12, No. 9, July 2002, pp. 869-896.

A. Jadbabaie, J. Lin, and A. S. Morse. Coordination of groups of mobile autonomous agents using nearest neighbor rules. IEEE Conference on Decision and Control, Las Vegas, NV, 2002.

A. Jadbabaie and A.S. Morse. On the ISS property for receding horizon control of constrained linear systems.IFAC World Congress, Barcelona, Spain, July 2002.

R. Murray, J. Hauser, A. Jadbabaie, M. Milam, W. Dunbar, and R. Franz, in G. Balas and T. Samad, editors. Online control customization via optimization based control. Software Enabled Control: Information Technologies for Dynamical Systems. John Wiley and Sons, 2002.


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Dwight L. Jaggard

Professor of Electrical and Systems Engineering; Undergraduate Curriculum Chair
Email: jaggard at ee.upenn.edu
Personal Website

Research Interests:
Fractal Electrodynamics: The interaction of electromagnetic waves with fractal structures defines the area of fractal electrodynamics. We investigate ways in which multi-scale structures imprint their geometry on interrogating waves and methods by which self-similarity can be used to design new classes of filters and radiators. Applications include the remote description of rough surfaces, scattering from and inverse scattering of fractal superlattices, and the synthesis of novel fractal antennas and arrays. Electromagnetic Chirality: The chirality parameter provides an extra degree of freedom (along with permittivity and permeability) for the design of new microwave, millimeter wave and optical devices. This parameter indicates the "handedness" of the material. We examine theoretically and numerically new classes of chiral filters, radiators, shields and guiding structures. Waves, Topology, and Symmetry: We investigate the effect of topology and symmetry on wave scattering and propagation through the study of wave interactions with families of canonical knots and unknots. Initial studies indicate the importance of polarization in remotely classifying several groups of wire scatterers.

Selected Recent Publications:

Laksari, Y., Aubert, H., Jaggard, D.L., et al. Lacunarity of fractal superlattices: A remote estimation using wavelets. IEEE Transactions on Antennas and Propagation, 53(4), 1358-1363, April 2005.

Yang, X., Wu, T.X., and Jaggard, D.L. Physical properties of wave scattering by a chiral grating. Journal of the Optical Society of America A: optics And Image Science, and Vision, v 21, n 11, November 2004, p 2109-2116.

K. Eftaxias, P. Frangos, P. Kapiris, J. Ploygiannakis, J. Kopanas, A. Petzakis, P. Skountzos and D. Jaggard, "Review and a Model of Pre-seismic Electromagnetic Emissions in terms of Fractal Electrodynamics," Fractals 12, 243 (2004).

Y. Laksari, H. Aubert, D. L. Jaggard and J. Y. Tourneret. Lacunarity of Fractal Superlattices: A Remote Estimation Using Wavelets. to appear in IEEE Trans. Ant. Propagat, 2004.

X. Yang, T. X. Wu and D. L. Jaggard. Scattering of Chiral Photonic Crystal. IEEE Transactions on Antennas and Propagation, v 52, n 1, 2004, p 1859-1870.

Chin, C., Wehrli, F.W., Hwang, S.N., Jaggard, D.L., Hackney, D.B., and Wehrli, S.W. Feasibility of probing boundary morphology of structured materials by 2D NMR q-space imaging. Journal of Magnetic Resonance, v 160, n 1, January 2003, p 20-25.

C-L Chin, F. W. Wehrli, S. N Hwang, D. L. Jaggard, D. B. Hackney and SuW. Wehrli. Feasibility of Probing Boundary Morphlogy of Biological Cells and Tissues by NMR 2D q-Space Imaging. submitted for publication (August 2002), appeared fall 2002.

Y., Laksari, H. Aubert and D. L. Jaggard. A Wavelet-Based Partition Function for the Remote Analysis of Discrete Self-Similar Objects. Elec. Lett. 38, 741-742, July 2002.

O. Manuar and D. L. Jaggard. From Loop to Trefoil. to appear in the IEEE Trans. Ant. and Propagat, 2002.

X. Yang, T. X. Wu and D. L. Jaggard. Synchronization Recovery of Chaotic Wave Thourgh An Imperfect Channel. IEEE Antennas and Wireless Propagat. Lett. 1, 154-156, 2002.



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Aravind K. Joshi

Henry Salvatori Professor of Computer and Cognitive Science
Email: joshi at cis.upenn.edu
Personal Website

Research Interests:
Natural-language processing, natural-language interfaces, artificial intelligence, cognitive science.

Selected Recent Publications:
Shen L.B. and Joshi, A.K. Flexible margin selection for reranking with full pairwise samples. Natural Language Processing – IJCNLP 2004, 3248:446-455 2005.

Joshi, A.K. Domains of locality. Data and Knowledge Engineering, v 50, n 3 SPEC. ISS., September 2004, p 277-289.

Joshi, A.K. Starting with complex primitives pays off: complicate locally, simplify globally. Cognitive Science, 28(5), September-October 2004, p 637-668.

Forbes, K., Miltsakaki, E., Prasad, R., Sarkar, A., Joshi, A., Webber, B. D-LTAG system: discourse parsing with a lexicalized tree-adjoining grammar. Journal of Logic, Language and Information, v 12, n 3, Summer 2003, p 261-79.

Joshi, A.K. A note on the strong and weak generative powers of formal systems. Theoretical Computer Science, v 293, n 2, 6 Feb. 2003, p 243-59.

Joshi, A.K. Starting with complex primitives pays off. Computational Linguistics and Intelligent Text Processing. 4th International Conference, CICLing 2003. Proceedings (Lecture Notes in Computer Science Vol.2588), 2003, p 1-10.

Allbeck, J., Kipper, K., Adams, C., Schuler, W., Zoubanova, E., Badler, N., Palmer, M., Joshi, A. ACUMEN: amplifying control and understanding of multiple entities. Proceedings of the First International Joint Conference on Autonomous Agents and Multiagent Systems, 2002, p 191-8.


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Sampath Kannan

Professor of Computer and Information Science
Email: kannan at cis.upenn.edu
Personal Website

Research Interests:
Program checking, probabilistic algorithms, learning theory, graph theory and combinatorics, computational biology, algorithms for code generation.

Selected Recent Publications:

Feigenbaum, J., Kannan, S., McGregor, A., Suri, S., and Zhang, J. Graph distances in the streaming model: The value of space. Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms, Proceedings of the Sixteenth Annual ACM-SIAM Symposium of Discrete Algorithms, 2005, p 745-754.

Feighenbaum, J., Kannan, S., and Zhang, J. Computing diameter in the streaming and sliding-window models. Algorithmica, v 41, n 1 Januray 2005, p 25-41.

Isler, V., Kannan, S., and Daniilidis, K. Sampling based sensor-network deployment. 2004 IEEE/RSJ International Conference on Intelligent Robots and Systems, v 2, 2004, p 1780-1785.

Batu, T., S. Guha, and S. Kannan. Inferring Mixtures of Markov Chains. Proceedings Computational Learning Theory (COLT), 2004, p 186-199.

Alur, R., Kannan, S., and La Torre, S. Polyhedral flows in hybrid automata. Formal Methods in System Design, v 24, n 3, May 2004, p 261-280.

Batu, Tugkan, Kannan, Sampath, Khanna, Sanjeev, McGregor, Andrew. Reconstructing Strings from Random Traces. Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms, v 15, 2004, p 903-911.

Feigenbaum, J., S. Kannan, A. McGregor, S. Suri, and J. Zhang. On Graph Problems in a Semi-Streaming Model. Proc. ICALP, 2004: 531-543.

Goldberg, L. M. Jerrum, S. Kannan, and M. Paterson. A Bound on the Capacity of Backoff and Acknowledgement-Based Protocols. SIAM J. Computing. Vol 33. No. 2, p 313-331, 2004.

Isler, Volkan, Kannan, Sampath, Khanna, Sanjeev. Randomized Pursuit-Evasion with Limited Visibility. Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms, v 15, 2004, p 1053-1062. Isler, V., Kannan, S., Daniilidis, K., Valtr, P. VC-dimension of exterior visibility. IEEE Transactions on Pattern Analysis and Machine Intelligence, v 26, n 5, May 2004, p 667-71.

V. Isler and S. Kannan and S. Khanna. Locating and Capturing an Evader in a Polygonal Environment. Sixth International Workshop on the Algorithmic Foundations of Robotics,351-366, 2004.

Kim, Moonzoo, Viswanathan, Mahesh, Kannan, Sampath, Lee, Insup, Sokolsky, Oleg. Java-MaC: A Run-Time Assurance Approach for Java Programs. Formal Methods in System Design, v 24, n 2, March, 2004, p 129-155.

Isler, V., Kannan, S., Daniilidis, K. Local exploration: online algorithms and a probabilistic framework. 2003 IEEE International Conference on Robotics and Automation (Cat. No.03CH37422), 2003, pt. 2, p 1913-20 vol.2.

Feigenbaum, Joan, Kannan, Sampath, Strauss, Martin J., Viswanathan, Mahesh An approximate L1-difference algorithm for massive data streams. SIAM Journal on Computing, v 32, n 1, January, 2003, p 131-151.

Kannan, Sampath, Khanna, Sanjeev. Selection with monotone comparison costs Source: Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms, 2003, p 10-17.

Anderson, R., S. Kannan, H. Karloff, and R.E. Ladner. Thresholds and optimal binary comparison search trees. J. Algorithms 44(2): 2002, p 338-358. Feigenbaum, J., Kannan, S., Strauss, M., Viswanathan, M. Testing and Spot-Checking of Data Streams. Algorithmica (New York), v 34, n 1, September, 2002, p 67-80.

Moonjoo Kim, Kannan, S., Insup Lee, Sokolsky, O., Viswanathan, M. Computational analysis of run-time monitoring - fundamentals of Java-MaC. Electronic Notes in Theoretical Computer Science, v 70, n 4, 2002.


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Saleem A. Kassam

Solomon and Sylvia Charp Professor of Electrical and Systems Engineering
Email: kassam at ee.upenn.edu
Personal Website

Research Interests:
Current research interests are in Communication Systems, Wireless Channels, Blind Signal Separation, Channel Equalization, and in High- Resolution Imaging Arrays. Applications of this research include wireless communications, data transmission, image analysis, radar and sonar, and medical applications including ultrasound imaging and brain activity monitoring. Research is conducted with graduate students pursuing Ph.D. degrees, and other faculty members, in the Moore School of Electrical Engineering.

Selected Recent Publications:

Tang, W., and Kassam, S.A. Statistical Characteristics of the Envelope in Diversity Combining of Two Correlated Rayleigh Fading Channels. IEE Proceedings – Communications. (under review)

Ahmad, F., Amin, M.G., and Kassam, S.A. Synthetic Aperture Beamformer for Imaging through a Dielectric Wall. IEEE Trans. Aerospace & Electronic Systems, 41, 2005, v 41, n 1, January 2005, p 271-283.

He, L., Kassam, S.A., and Thaiuppathump, T. Blind Separation of Complex I/Q Independent Sources with Phase Recovery. IEEE Signal Processing Letters, v 12, n 5, May 2005, p 419-422.

Ahmad, F., Amin, M.G., and Kassam, S.A. Through-the-wall wideband synthetic aperture beamformer. IEEE Antennas and Propagation Society, AP-S International Symposium, v 3, 2004, p 3059-3062.

Guo, Y., Kassam, S.A., Ahmad, F., and Amin, M. Reduced complexity multi-frequency imaging using active aperture synthesis. IEEE Antennas and Propagation Society, AP-S International Symposium (Digest), v 3, 2004, p 3071-3074.

Zhang, Y., Kassam, S.A. Robust rank-EASI algorithm for blind source separation. IEEE Proceedings: Communications, v 151, n 1, February, 2004, p 15-19.

Ahmad, F., Frazer, G.J., Kassam, S.A., Amin, M.G. Design and implementation of near-field, wideband synthetic aperture beamformers. IEEE Transactions on Aerospace and Electronic Systems, v 40, n 1, Jan. 2004, p 206-20.

Ahmad, F., Amin, M.G., Kassam, S.A., Frazer, G.J. A wideband, synthetic aperture beamformer for through-the-wall imaging. IEEE International Symposium on Phased Array Systems and Technology 2003 (IEEE Cat. No.03TH8681), 2003, p 187-92.

Ahmad, Fauzia, Frazer, Gordon J., Kassam, Saleem A., Amin, Moeness G. A new approach for near-field wideband synthetic aperture beamforming. ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings, v 5, 2003, p 89-92.


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Michael Kearns

Professor of Computer and Information Science; National Center Chair in Resource Management and Technology; Co-Director of the Institute for Research in Cognitive Science; Secondary Appointment in Operations and Information Management in the Wharton School
Email: mkearns at cis.upenn.edu
Personal Website

Research Interests:
My primary research interests are in artificial intelligence and machine learning, including computational learning theory, reinforcement learning, probabilistic inference and graphical models, and computational issues in game theory and economics. I have worked on a variety of applications of AI to human-computer interaction, including spoken dialogue systems and software agents in MUDs. I also have interests in cryptography and network security, theoretical computer science, and computational finance.

Selected Recent Publications:
M. Kearns, K. Crammer, and J. Wortman. Learning from Data of Variable Quality. Preprint under revision, 2005.

M. Kearns, Y. Nevmyvaka and Y. Feng. Reinforcement Learning for Optimized Trade Execution. Preprint under revision, 2005.

M. Kearns, J. Jacobs, J. Wortman, M. Kahana and I. Fried. Machine Learning for Multi-Cell Human Intent Inference. Preprint under revision, 2005.

M. Kearns and S. Suri. Networks Preserving Evolutionary Stability and Power of Randomization. Prepring under revision, 2005.

M. Kearns, Y. Nevmyvaka, A. Papandreou and K. Sycara. Electronic Trading in Order-Driven Markets: Efficient Execution. IEEE Conference on Electronic Commerce, 2005.

M. Kearns. Economics, Computer Science, and Policy. Issues in Science and Technology, v 21, n 2, Winter 2005, p 37-47.

M. Kearns, S. Kakade, Y. Mansour and L. Ortiz. Competitive Algorithms for VWAP and Limit Order Trading. To appear, ACM Conference on Electronic Commerce, 2004.

M. Kearns, S. Kakade and L. Ortiz. Graphical Economics. COLT 2004.

M. Kearns, S. Kakade, L. Ortiz, R. Pemantle, and S. Suri. Economics Properties of Social Networks. In Proceedings of NIPS 2004.

M. Kearns, S. Kakade and J. Langford. Exploration in Metric State Spaces. ICML 2003.

M. Kearns, S. Kakade, J. Langford, and L. Ortiz. Correlated Equilibria in Graphical Games. ACM Conference on Electronic Commerce, 2003.

M. Kearns, L. Ortiz. Algorithms for Interdependent Security Games. NIPS 2003.

M. Kearns, L. Ortiz. The Penn-Lehman Automated Trading Project. IEEE Intelligent Systems, Nov/Dec 2003.

M. Kearns, E. Allender, S. Arora, C. Moore, A. Russell. A Note on the Representational Incompatabilty of Function Approximation and Factored Dynamics. Proceedings of NIPS 2002.

M. Kearns, C. Isbell, S. Singh, D. Litman, J. Howe. CobotDS: A Spoken Dialogue System for Chat. Proceedings of AAAI 2002.

M. Kearns, Y. Mansour. Efficient Nash Computation in Large Population Games with Bounded Influence. Proceedings of UAI 2002

M. Kearns, L. Ortiz. Nash Propagation for Loopy Graphical Games. Proceedings of NIPS 2002.


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John D. Keenan

Professor of Electrical & Systems Engineering
Email: keenan at seas.upenn.edu
Personal Website

Research Interests:
Biological and health effects of pollution, wastewater treatment, water resources engineering, environmental impact assessment, hazardous materials in the environment.

Selected Recent Publications:
J.D. Keenan, Manaf El-Farhan, P. H. Chin-Hong, and W. K. Shieh. Performance of Anaerobic Reactors during Pseudo--Steady State Operation. Journal of Chemical Technology & Biotechnology 69, 45-57, 1997.

J.D. Keenan, Marc E. Norman and Patrick T. Harker. A Spatial Price Equilibrium Analysis of Market--Based Incentives to Abate Nonpoint Source Nutrient Water Pollution. Journal of Environmental Systems 24, 4, 409-44, 1996.

J.D. Keenan and Marc E. Norman. Market Incentives to Reduce Nonpoint Source Agricultural Nutrient Pollution: A Theoretical and Implementational Discussion. Journal of Environmental Systems 24, 2, 151-167, 1995.


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Sanjeev Khanna

Associate Professor of Computer and Information Science
Email: sanjeev at cis.upenn.edu
Personal Website

Research Interests:
Approximation algorithms, combinatorial optimization, hardness of approximation, network design and routing, and scheduling.

Selected Recent Publications:

S. Khanna, C. Chekuri. A PTAS for the Multiple Knapsack Problem. To appear in SIAM Journal on Computing (SICOMP).

S. Khanna, J. Naor and F.B. Shepherd. Directed Network Design Problems with Orientation Constraints.To appear in SIAM Journal on Discrete Mathematics (SIDMA).

N. Bansal, M. Charikar, S. Khanna, and J. Naor. Approximating the average response time in broadcast scheduling. Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms, 2005, p 215-221.

S. Khanna, C. Chekuri, S. Naor, and L. Zosin. A linear programming formulation and approximation algorithms for the metric labeling problem. SIAM Journal on Discrete Mathematics, 18(3), 2005, p 608-625.

S. Khanna, C. Chekuri, and F.B. Shepherd. Edge Disjoint Paths in Planar Graphs. Proc. 45th IEEE Symposium on Foundations of Computer Science, 2004.

S. Khanna, J. Chuzhoy, S. Guha, and S. Naor. Machine Minimization for Scheduling Jobs with Interval Constraints. Proc. 45th IEEE Symposium on Foundations of Computer Science, 2004.

Andreas Björklund, Thore Husfeldt, Sanjeev Khanna. Approximating Longest Directed Paths and Cycles. Proc. 31st International Colloquium on Automata, Languages, and Programming (ICALP), 2004.

S. Khanna, T. Batu, S. Kannan, and A. McGregor. Reconstructing strings from random traces. Proc. 15th Annual Symposium on Discrete Algorithms (SODA), pp. 910-918, 2004.

S. Khanna, P. Buneman, K. Tajima, and W. Tan. Archiving Scientific Data. ACM Transactions on Database Systems (TODS), 29: 2-42, 2004. (Special issue devoted to papers invited from SIGMOD/PODS 2003.)

S. Khanna, C. Chekuri. Approximation Algorithms for Minimizing Average Weighted Completion Time. Handbook of Scheduling, Chapman & Hall/CRC Computer and Information Science Series, Joseph Y-T. Leung (Ed.) 2004.

S. Khanna, C. Chekuri. On Multidimensional Packing Problems. SIAM Journal on Computing (SICOMP), 33(4), 837-851, 2004.

S. Khanna, C. Chekuri and F. B. Shepherd. The All-or-Nothing Multicommodity Flow Problem.36th ACM Symposium on Theory of Computing (STOC), 2004.

S. Khanna, C. Chekuri, A. Goel, and A. Kumar. Multi-processor Scheduling to Minimize Flowtime with eps Resource Augmentation. 36th ACM Symposium on Theory of Computing (STOC), 2004.

S. Khanna, J. Chuzhoy, S. Guha, E. Halperin, G. Kortsarz, R. Krauthgamer, and S. Naor. Asymmetric k-center is log^*n-hard to Approximate. 36th ACM Symposium on Theory of Computing (STOC), 2004.

S. Khanna, M. Greenwald. Power-Conserving Computation of Order-Statistics over Sensor Networks. 23rd ACM Symposium on Principles of Database Systems (PODS), 275-285, 2004.

S. Khanna, V. Guruswami. On the Hardness of $4$-coloring a $3$-colorable Graph. SIAM Journal on Discrete Mathematics (SIDMA), 18(1), 30-40, 2004.

S. Khanna, V. Isler and S. Kannan. Randomized pursuit-evasion with limited visibility. Proc. 15th Annual Symposium on Discrete Algorithms (SODA), pp. 1060-1069, 2004.

S. Khanna, M. Adler, S. Khanna, R. Rajaraman, A. Rosén. Time-Constrained Scheduling of Weighted Packets on Trees and Meshes. Algorithmica 36(2): 123-152, 2003.

S. Khanna, C. Chekuri. Edge Disjoint Paths Revisited. Proc. 14th Annual Symposium on Discrete Algorithms (SODA), 2003.

S. Khanna, V. Guruswami, B. Shepherd, R. Rajaraman and M. Yannakakis. Near-Optimal Hardness Results and Approximation Algorithms for Edge-Disjoint Paths and Related Problems.Journal of Computer and System Sciences (JCSS), 67(3), 473-496, 2003.

S. Khanna, S. Kannan. Selection with Monotone Comparison Costs. Proc. 14th Annual Symposium on Discrete Algorithms (SODA), 2003.

S. Khanna, P. Buneman, K. Tajima, and W. Tan. Archiving Scientific Data.ACM SIGMOD International Conference on Management of Data (SIGMOD), 2002.

S. Khanna, P. Buneman and W. Tan. On Propagation of Deletions and Annotations through Views. 21st ACM Symposium on Principles of Database Systems (PODS), 2002.

S. Khanna, C. Chekuri. Approximation Schemes for Preemptive Weighted Flow Time. 34th ACM Symposium on Theory of Computing (STOC), 2002.


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Mahadevan Khantha

Research Assistant Professor of Materials Science and Engineering
Email: khantha at seas.upenn.edu
Personal Website

Research Interests:
Deformation of metals and compounds, brittle-ductile transition, strain relaxation in thin films, yield and mechanical behavior of nanostructures, and modeling of glass transition. Dr. Khantha is an expert in the statistical mechanics of defects and failure in crystalline solids. She has advanced a new theory of the brittle-ductile transition based on a novel cooperative model of defect nucleation at finite temperatures. She is currently adapting this approach to study the nucleation of defects in other restricted geometries such as thin films and nanostructures. She has also done extensive modeling of deformation of metals and compounds using atomistic simulation of defects in crystals

Selected Recent Publications:
Khantha, M., Cordero, N.A., Molina, L.M., et al. Interaction of lithium with graphene: An ab initio study. Physical Review B 70 (12): Art. NO. 125422 September 2004.

Chen, Hao, Khantha, Mahadevan, Egami, Takeshi. Effect of compositional short range order on glass formation in binary metallic system. Materials Research Society Symposium - Proceedings, v 754, 2003, p 65-70.

Khantha, M., Vitek, V., Pope, D.P. Strain-rate dependence of the brittle-to-ductile transition temperature in TiAl. Materials Research Society Symposium - Proceedings, v 646, 2001, p N1111-N1116.

Khantha, M., Vitek, V., Pope, D.P. Strain-rate dependent mechanism of cooperative dislocation generation: application to the brittle-ductile transition. Materials Science & Engineering A (Structural Materials: Properties, Microstructure and Processing), v A319-321, Dec. 2001, p 484-9.


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Daniel E. Koditschek

Alfred Fitler Moore Professor of Electrical and Systems Engineering
Email: kod at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Sensor driven dynamically dexterous robot manipulation. Learning piecewise linear functional approximants. Computational neuromechanics.

Selected Recent Publications:
Lin PC, Komsuoglu H, Koditschek DE. A leg configuration measurement system for full-body pose estimates in a hexapod robot. IEEE TRANSACTIONS ON ROBOTICS 21 (3): 411-422 JUN 2005

Karagoz CS, Bozma HI, Koditschek DE. Feedback-based event-driven parts moving. IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION 20 (6): 1012-1018 DEC 2004

Altendorfer R, Koditschek DE, Holmes PStability analysis of legged locomotion models by symmetry-factored return maps. TERNATIONAL JOURNAL OF ROBOTICS RESEARCH 23 (10-11): 979-999 OCT-NOV 2004.

Altendorfer R, Koditschek DE, Holmes P.Stability analysis of a clock-driven rigid-body SLIP model for RHex . INTERNATIONAL JOURNAL OF ROBOTICS RESEARCH 23 (10-11): 1001-1012 OCT-NOV 2004

Koditschek DE, Full RJ, Buehler M. Mechanical aspects of legged locomotion control. ARTHROPOD STRUCTURE & DEVELOPMENT 33 (3): 251-272 JUL 2004

Saranli U, Rizzi AA, Koditschek DE. Model-based dynamic self-righting maneuvers for a hexapedal robot. INTERNATIONAL JOURNAL OF ROBOTICS RESEARCH 23 (9): 903-918 SEP 2004

Groff RE, Khargonekar PP, Koditschek DE. A local convergence proof for the minvar algorithm for computing continuous piecewise linear approximations. SIAM JOURNAL ON NUMERICAL ANALYSIS 41 (3): 983-1007 2003

Westervelt ER, Grizzle JW, Koditschek DE. Hybrid zero dynamics of planar biped walkers. IEEE TRANSACTIONS ON AUTOMATIC CONTROL 48 (1): 42-56 JAN 2003

Cowan NJ, Weingarten JD, Koditschek DE. Visual servoing via navigation functions.
IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION 18 (4): 521-533 AUG 2002

Klavins E, Koditschek DE. Phase regulation of decentralized cyclic robotic systems.
INTERNATIONAL JOURNAL OF ROBOTICS RESEARCH 21 (3): 257-275 MAR 2002.

Nakanishi Y, Fukuda T, Koditschek DE. Brachiation on a ladder with irregular intervals. ADVANCED ROBOTICS 16 (2): 147-160 2002

Ghrist RW, Koditschek DE. Safe cooperative robot dynamics on graphs. SIAM JOURNAL ON CONTROL AND OPTIMIZATION 40 (5): 1556-575 JAN 9 2002

Karagoz CS, Bozma HI, Koditschek DE. EDAR - mobile robot for parts moving based on a game-theoretic approach. ELECTRONICS LETTERS 38 (3): 147-148 JAN 31 2002


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Vijay Kumar

Chair of Mechanical Engineering and Applied Mechanics; Professor of Computer and Information Science
Email: kumar at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
Robotics; coordination of multiple robotic vehicles; modeling, analysis and synthesis of biomolecular networks; multi-body dynamics with frictional contacts.

Selected Recent Publications:
L. Chaimowicz, A. Cowley, B. Grocholsky, M. A. Hsieh, J. F. Keller, V. Kumar, and C. J. Talor, “Deploying Air-Ground Multi-Robot Teams in Urban Environments,” Proceedings of the Third Multi-Robot Systems Workshop, Washington, DC, March 2005.

S. Chitta, P. Cheng, E. Frazzoli, and V. Kumar, “RoboTrikke: A Novel Undulatory Locomotion System,” IEEE International Conference on Robotics and Automation, April 18-22, Barcelona, Spain.

R. Rao, V. Kumar, and C. J. Taylor, “Planning and Control of Mobile Robots in Image Space from Overhead Cameras,” IEEE International
Conference on Robotics and Automation, April 18-22, Barcelona, Spain.

B. Grocholsky, R. Swaminathan, J. Keller, V. Kumar and G. Pappas, “Information Driven Coordinated Air-Ground Proactive Sensing,” IEEE
International Conference on Robotics and Automation, April 18-22, Barcelona, Spain.

L. Chaimowicz, N. Michael, and V. Kumar, “Controlling Swarms of Robots Using Interpolated Implicit Functions,” IEEE International
Conference on Robotics and Automation, April 18-22, Barcelona, Spain.

S. P. Parikh, V. Grassi, V. Kumar, and J. Okamoto, “Usability Study of a Control Framework for an Intelligent Wheelchair,” IEEE International Conference on Robotics and Automation, April 18-22, Barcelona, Spain.

Tanner, H. G., Kumar, V. and G. J. Pappas, “Leader-to-Formation Stability,” IEEE Transactions on Robotics and Automation, June, 2004.

P. Song, J.S. Pang, and V. Kumar, “A Semi-Implicit Time-Stepping Model for Frictional Compliant Contact Problems”. International Journal for Numerical Methods in Engineering, Accepted for publication,Vol. 60, June 2004: 2231-2261.

J. Esposito and V. Kumar, “An Asynchronous Integration and Event Detection Algorithm for Simulating Multi-Agent Hybrid Systems,” ACM Transactions on Modeling and Computer Simulation, 2004,in press.

Belta, C., and Kumar, V. “Abstractions and Control Policies for a Swarm of Robots,” IEEE Transactions on Robotics, vol.20, no.5, 2004: 865-875.

G. A. S. Pereira, V. Kumar, and M. F. M. Campos, “Decentralized Algorithms for Multirobot Manipulation via Caging,” in International Journal of Robotics Research, Accepted for publication, 2004.

V. Kumar, D. Rus, and S. Singh, “Robot and Sensor Networks for First Responders,” IEEE Pervasive Computing, October-December 2004: pp 24-33.
Belta, C., Esposito, J. M., Kim, J, and Kumar, V., “Computational techniques for analysis of genetic network dynamics,” Int. Journal of Robotics Research, 2004.

P. Song, J. Trinkle, V. Kumar, and J. Pang, “Design of Part Feeding and Assembly Processes with Dynamics,” IEEE International Conference on
Robotics and Automation, New Orleans, LA, April 2004.

R. Rao, C. J. Taylor, and V. Kumar, “Experiments in Robot Control from Uncalibrated Overhead Imagery,” Proceedings of the 9th International Symposium of Experimental Robotics,Singapore, June 2004.

B. Grocholsky, S. Bayraktar, V. Kumar, C. J. Taylor, and G. Pappas, “Synergies in Feature Localization by Air-Ground Teams,” Proceedings of the 9th International Symposium of Experimental Robotics,Singapore, June 2004.

R. Rao, C. J. Taylor, and V. Kumar, “Calibrating an Air-Ground Control System from Motion Correspondences,” Proceedings of the IEEE International Conf. on Computer Vision and Pattern Recognition,Washington D.C., June 2004.

L. Chaimowicz and V. Kumar, “Aerial Shepherds: Coordination among UAVs and Swarms of Robots,” 7th International Symposium on Distributed
Autonomous Robotic Systems, Toulouse, France, June 23-25, 2004.

J. Esposito, J. W. Kim, and V. Kumar, “Adaptive RRT’s for Validating Hybrid Robotic Control Systems,” 6th International Workshop on Algorithmic Foundations of Robotics, Utrecht, Netherlands, July 11-13, 2004.

Zhang, F., Pereira, G., and V. Kumar, “Necessary and Sufficient Conditions for Localization of Robot Networks,” ASME International Design Engineering Technical Conferences, Mechanics and Robotics Conference, Salt Lake City, 2004 (Finalist, Mechanisms and Robotics Best Paper Award).

Stump, E. and V. Kumar, “Workspace Delineation of Cable-Actuated Parallel Manipulators,” ASME International Design Engineering Technical Conferences, Mechanics and Robotics Conference, Salt Lake City, 2004.

Chitta, C., Heger, F., and V. Kumar, “Design, Analysis, Simulation and Experimental Results for a Rollerblading Robot,” ASME International Design Engineering Technical Conferences, Mechanics and Robotics Conference, Salt Lake City, 2004.


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Kenneth R. Laker

Professor and Graduate Group Chair of Electrical and Systems Engineering
Email: laker at ee.upenn.edu


Research Interests:
Mixed mode integrated circuit design and testing: High performance, low-power data acquisition and RF systems have many important applications and present challenging obstacles for design, implementation and testing. The primary areas of research are the development of architectures that enable the realization of high dynamic range requirements when implemented in low voltage technologies; explore distributed and parallel architectures that expand the signal bandwidth available in over sampled analog-to-digital converters; switched capacitor systems; and development of robust test methodologies for mixed-signal and RF ICs

Selected Recent Publications:
Chao Xu, Sargeant, W., Laker, K.R., Van der Spiegel, J. A fully integrated CMOS phase-locked loop with 30 MHz to 2 GHz locking range and +or-35 ps jitter. Analog Integrated Circuits and Signal Processing, v 36, n 1-2, July-Aug. 2003, p 91-7.

Chao Xu, Barber, F., Laker, K., Van der Spiegel, J. Analysis of clock buffer phase noise. 2002 IEEE International Symposium on Circuits and Systems. Proceedings (Cat. No.02CH37353), 2002, pt. 5, p V-657-60 vol.5.

Chao Xu, Sargeant, W., Laker, K., Van der Spiegel, J. An extended frequency range CMOS voltage-controlled oscillator. ICECS 2002. 9th IEEE International Conference on Electronics, Circuits and Systems (Cat. No.02EX611), 2002, pt. 2, p 425-8 vol.2.

Geselowitz MN, Sloan ME, Laker KR. Guest editorial: The educational activities of the IEEE history center. IEEE TRANSACTIONS ON EDUCATION 45 (3): 205-208 AUG 2002.

Sun, Xiaohong, Laker, Kenneth R. Tonal behavior analysis of an adaptive second-order sigma-delta modulator. Proceedings - IEEE International Symposium on Circuits and Systems, v 4, 2002, p IV/277-IV/280.


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Daniel Lee

Assistant Professor of Electrical and Systems Engineering and Bioengineering (Secondary Appointment)
Email: ddlee at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Applying neural approaches to machine learning and other engineering systems problems. Dr. Lee's strengths in modern probabilistic and nonlinear modeling techniques, learning theories, robotics and machine learning will be a great asset to the Electrical Engineering Department's research programs. He brings a new dimension to the Neuroengineering Program at Penn and will strengthen ties with GRASP, IRCS, and the Departments of Bioengineering and Computer and Information Science.

Selected Recent Publications:
J. H. Ham, D. D. Lee, and S. Mika, and B. Schoelkopf. A kernel view of the dimensionality reduction of manifolds. to appear in Proceedings of the International Conference on Machine Learning, 2004.

Y. Lin, D. D. Lee and L. K. Saul. Nonnegative deconvolution for time of arrival estimation. to appear in International Conference on Acoustics, Speech, and Signal, 2004.

N. G. Hockstein, E. R. Thaler, W. T. Miller, D. A. Torigian, D. D. Lee, C. W. Hanson. Diagnosis of Pneumonia Using an Electronic Nose: A Prospective Study. Proceedings of the Triological Society, 2004.

B. D. Mensh, E. Aksay, D. D. Lee, H. S. Seung and D. W. Tank. Spontaneous eye movements in goldfish: oculomotor integrator performance, plasticity, and dependence on visual feedback. Vision Research 44, 711-726, 2004.

O. L. White, D. D. Lee and H. Sompolinsky. Short-term memory in orthogonal neural networks. Phys. Rev. Lett. 92, 148102, 2004.

D. Cohen, Y. H. Ooi, P. Vernaza, and D. D. Lee. The University of Pennsylvania Robocup 2003 Legged Soccer Team to appear in Robocup 2003: Robocup Soccer World Cup VII , 2003.

J. H. Ham, D. D. Lee, and L. K. Saul. Learning high dimensional correspondences with low dimensional manifolds. Proceedings of the ICML 2003 Workshop on The Continuum from Labeled to Unlabeled Data in Machine Learning and Data Mining, 34-41, 2003.

L. K. Saul, D. D. Lee, C. L. Isbell and Y. Lecun Real time voice processing with audiovisual feedback: toward autonomous agents with perfect pitch.. Advances in Neural and Information Processing Systems 15, 1181-1188 , 2003.

F. Sha, L. K. Saul, and D. D. Lee. Multiplicative updates for large margin classifiers. Proceedings of the Sixteenth Annual Conference on Computational Learning Theory, 188-202, 2003.

F. Sha, L. K. Saul and D. D. Lee. Multiplicative updates for nonnegative quadratic programming in support vector machines. Advances in Neural and Information Processing Systems 15, 1041-1048 , 2003.

D. D. Lee. Dimensionality reduction for sensorimotor learning in mobile robots. Proceedings of the SPIE 4479, 4-11, 2002.

L. K. Saul and D. D. Lee. Multiplicative updates for classification by mixture models. Advances in Neural and Information Processing Systems 14. 897-904, 2002.


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Insup Lee

Professor of Computer and Information Science
Email: lee at cis.upenn.edu
Personal Website

Research Interests:
Distributed systems, real-time computing, programming languages, operating systems, formal specification and analysis of time-dependent systems, and software engineering methods and tools.

Selected Recent Publications:
Penubarthi, C.; Myuhng-Joo Kim; Insup Lee. Security in sensor networks for medical systems torso architecture. Computational Science and Its Applications - ICCSA 2005. International Conference. Proceedings, Part I (Lecture Notes in Computer Science Vol. 3480),
2005, p 156-65.

Insik, S. and Insup L. Compositional real-time scheduling framework. Proceedings, 25th IEEE International Real-Time Systems Symposium, 2004, p 57-67.

Insup Lee, Oleg Sokolsky and George Pappas. Platform-Independent Autonomy Modeling. Proceedings of the 4th International Conference on Intelligent Systems Design and Applications (ISDA 2004), Budapest, Hungary, August 26-28, 2004.

Rajeev Alur, David Arney, Elsa L. Gunter, Insup Lee, Jaime Lee, Wonhong Nam, Frederick Pearce, Steve Van Albert, Jiaxiang Zhou. Formal specifications and analysis of the computer-assisted resuscitation algorithm (CARA) Infusion Pump Control System. International Journal in Software Tools for Technology Transfer, 2004, 4: 1-12.

Insik Shin, Insup Lee, and Sang Lyul Min. A Design Approach for Real-Time Embedded Systems with Energy and Code Size Constraints. Proceedings of the 10th Real-time and Embedded Computing Systems and Applications Conference, RTCSA 2004, Gothenburg, Sweden, August 25-27, 2004.

Oleg Sokolsky and Insup Lee. Resource Modeling for Embedded Systems Design, Proceedings of the Workshop on Software Technologies for Future Embedded and Ubiquitous Computing (WSTFEUS 2004), Vienna, Austria, May 11-12, 2004.

Usa Sammapun, Arvind Easwaran, Insup Lee, Oleg Sokolsky. Simulation of Simultaneous Events in Regular Expressions for Run-Time Verification. Proceeding of Runtime Verification Workshop (RV'04), Barcelona, Spain, April 3, 2004.

Yerang Hur, Jesung Kim, Insup Lee, and Jin-Young Choi. Sound Code Generation from Communicating Hybrid Models, Proceedings of Hybrid Systems: Computation and Control (HSCC04), Philadelphia, Pennsylvania, March 25-27, 2004, LNCS 2939, pp. 432-447, 2004.

Moonjoo Kim, Sampath Kannan, Insup Lee, Oleg Sokolsky, Mahesh Viswanathan. Java-MaC: a Rigorous Run-time Assurance Tool for Java Programs, Formal Methods in Systems Design, Vol 24, No 2, March 2004.

Usa Sammapun, Oleg Sokolsky. Proceedings of the 1st International Workshop on Automated Technology for Verification and Analysis (ATVA'03).Regular Expressions for Run-Time Verification, Taipei, Taiwan, December 10-12, 2003.

Insik Shin and Insup Lee. Periodic Resource Model for Compositional Real-Time Guarantees. Proceeding of the 24th IEEE Real-Time Systems Symposium, RTSS 2003 Cancun, Mexico, December 3-5, 2003Awarded as the Best Paper of RTSS 2003.

Li Tan, Jesung Kim, and Insup Lee.Testing and Monitoring Model-based Generated Program. Proceeding of Runtime Verification Workshop (RV'03), Boulder, Colorado, July 13, 2003.

Rajeev Alur, Franjo Ivancic, Jesung Kim, Insup Lee and Oleg Sokolsky. Generating Embedded Software from Hierarchical Hybrid Models. Proceeding of ACM SIGPLAN Languages, Compilers, and Tools for Embedded Systems (LCTES'03), San Diego, California, June 11-13, 2003.

Jesung Kim and Insup Lee. Modular Code Generation from Hybrid Automata based on Data Dependency. Proceedings of The 9th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS 2003), Washington, DC, May 27-30, 2003.

Hyoung Seok Hong, Sung Deok ?ha, Insup Lee, Oleg Sokolsky, and Hasan Ural. Data Flow Testing as Model Checking. Proceedings of ICSE'03, Portland, Oregon, May 3-10, 2003.

Insup Lee, Anna Philippou, and Oleg Sokolsky. Process Algebraic Modeling and Analysis of Power-Aware Real-Time Systems. Computing and Control Engineering Journal, Vol 13, Number 4, pp. 180-188, 2003.

Oleg Sokolsky, Anna Philippou, Insup Lee, and Kyriakos Christou. Modeling and Analysis of Power-Aware Systems. Proceedings of TACAS'03, Warsaw, Poland, April 7-11, 2003, LNCS 2619, pp. 409-425.

Rajeev Alur, Thao Dang, Joel Esposito, Yerang Hur, Franjo Ivancic, Vijay Kumar, Insup Lee, Pradyumna Mishra, George Pappas, and Oleg Sokolsky. Hierarchical Modeling and Analysis of Embedded Systems. Proceedings of IEEE, Vol. 91, No 1, January 2003, pp. 11-28 .

Insik Shin, Insup Lee, Sang Lyul Min. Embedded System Design Framework for Minimizing Code Size and Guaranteeing Real-Time Requirements. Proceedings of the 23rd IEEE Real-Time Systems Symposium, RTSS 2002, Austin, TX, December 2-5, 2002.

Insup Lee, Anna Philippou, and Oleg Sokolsky. A General Resource Framework for Real-Time Systems. Proceedings of the Monterey Workshop, Venice, Italy, October 8-11, 2002

Moonjoo Kim, Sampath Kannan, Insup Lee, Oleg Sokolsky, Mahesh Viswanathan. Computational Analysis of Run-time Monitoring - Fundamentals of Java-MaC, 2nd International Workshop on Run-time Verification. Copenhagen, Denmark, July 26, 2002; to appear in Electronic Notes in Theoretical Computer Science 70 No. 4.

Moonjoo Kim, Insup Lee, Usa Sammapun, Jangwoo Shin, Oleg Sokolsky. Monitoring, Checking, and Steering of Real-Time Systems. 2nd International Workshop on Run-time Verification. Copenhagen, Denmark, July 26, 2002; to appear in Electronic Notes in Theoretical Computer Science 70 No. 4.

Yerang Hur, Insup Lee. Distributed Simulation of Multi-Agent Hybrid Systems. IEEE International Symposium on Object-Oriented Real-time distributed Computing (ISORC), Crystal City, Virginia, USA, April 29-May 1, 2002.

. Hyoung Seok Hong, Insup Lee, Oleg Sokolsky, and Hasan Ural. A Temporal Logic Based Theory of Test Coverage and Generation International Conference on Tools and Algorithms for Construction and Analysis of Systems (TACAS2002), Grenoble, France, April 8 - 11, 2002.


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E. Christopher Lewis

Assistant Professor of Computer and Information Science
Email: eclewis at cis.upenn.edu
Personal Website

Research Interests:
Practical compilers and programming languages; computer architecture; and programming systems for scalable parallel machines.

Selected Recent Publications:
Corliss, M.L.; Lewis, E.C.; Roth, A. Using DISE to protect return addresses from attack. Computer Architecture News, v 33, n 1, March 2005, p 65-72.

Marc L. Corliss, E Christopher Lewis, and Amir Roth. "The Implementation and Evaluation of Dynamic Code Decompression using DISE," ACM Transactions on Embedded Computing Systems, 4(1):38-72, February 2005.

Marc L. Corliss, E Christopher Lewis, and Amir Roth, "Low-Overhead Debugging via Flexible Dynamic Instrumentation via DISE," In the Proceedings of the Eleventh International Symposium on High-Performance Computer Architecture (HPCA-11), pages 303-314, February 2005.

Colin Blundell, E Christopher Lewis, and Milo M.K. Martin, "Deconstructing Transactional Semantics: The Subtleties of Atomicity," In the Proceedings of the Annual Workshop on Duplicating, Deconstructing, and Debunking (held in conjunction with ISCA), June 2005.
Marc L. Corliss, E Christopher Lewis, and Amir Roth. "Using DISE to Protect Return Addresses from Attack," In the Proceedings of the Workshop on Architectural Support for Security and Anti-Virus (held in conjunction with ASPLOS), October 2004.

Marc L. Corliss, E Christopher Lewis, and Amir Roth. DISE: A Programmable Macro Engine for Customizing Applications. in Proceedings of the Thirtieth International Symposium on Computer Architecture (ISCA-30), June 2003.

Marc L. Corliss, E Christopher Lewis, and Amir Roth. A DISE Implementation of Dynamic Code Decompression. in Proceedings of the Conference on Languages, Compilers, and Tools for Embedded Systems (LCTES '03), June 2003.

Marc L. Corliss, E Christopher Lewis and Amir Roth. DISE: Dynamic Instruction Stream Editing. CIS Technical Report MS-CIS-02-24, Jul. 2002.


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Noam Lior

Professor of Mechanical Engineering and Applied Mechanics
Email: lior at seas.upenn.edu
Personal Website

Research Interests:
Combustion: Heat & mass transfer, fluid dynamics and kinetics of combustion processes in novel, low-emissions combustors for different fuels, with focus on pulverized coal. Development of the radiatively-conductively stabilized combustor. Energy conversion: Development and analysis of novel high-efficiency low pollution power generation system, using fossil, renewable, and nuclear energy. Fuel cells. Solar heating and cooling. Energy storage. Exergy analysis. Water desalination and flash evaporation: Heat & mass transfer, fluid dynamics and evaporation analysis for the improvement of existing water desalination processes, and for the development of novel ones. Flash evaporation. Measurements and control in water desalination. Membrane distillation. Manufacturing: Heat treatment (quenching) by gases: heat transfer and fluid mechanics in the gas, and distortions and microstructure and mechanical properties of the treated solids. Electrolytic removal of corrosion from steel: fluid mechanics, mass transfer and electrochemistry of the process. Crystal growth.

Selected Recent Publications:

N. Zuckerman and N. Lior. Impingement of heat transfer: Correlations and numerical modeling. Journal of Heat Transfer-Transactions of the ASME 127(5), May 2005, p 544-552.

N. Ipek, N. Lior, and A. Eklund. Improvement of the electrolytic metal pickling process by inter-electrode insulation. Ironmaking and Steelmaking, 32(1), February 2005, p 87-96.

A. M. Alklaibi and N. Lior. Transport analysis of air-gap membrane distillation. Journal of Membrance Science, v 255, n 1-2, June 15 2005, p 239-253.

R. Wiberg and N. Lior. Heat transfer from a cylinder in axial turbulent flows. International Journal of Heat and Mass Transfer, v 48, n 8, April 2005, p 1505-1517.

A. M. Alklaibi and N. Lior. Membrane-distillation desalination: Status and potential. Desalination, v 171, n 2, January 10 2005, p 111-131.

N. Lior and H.S. AL-Sharqawi. Exergy analysis of flow dehumidification by solid desiccants. Energy, v 30, n 6, May 2005, p 915-931.

N. Zhang, R. Cai, and N. Lior. A novel ammonia-water cycle for power and refrigeration cogeneration. American Society of Mechanical Engineers, Advanced Energy Systems Division AES, v 44, 2004, p 183-196.

N. Lior. The cooling process in gas quenching. Journal of Materials Processing Technology, v 155-156, 30 November 2004, p 1881-8.

R. Wiberg and N. Lior, Errors in thermochromic liquid crystal thermometry. Review of Scientific Instruments, v 75, n 9, September 2004, p 2985-2994.

R. Wieberg and N. Lior. Temperature measurements using thermochromic liquid crystals. Journal of Heat Transfr, v 126, n 4, August 2004, p 503-504.

P. Freund, Y. Kaya and N. Lior. Editors, Special Issue of Energy from The 6th International Conference on Greenhouse Gas Control Technologies - Kyoto, Japan, 1 - 4 October 2002; Energy,Vol. 29, Issues 9-10, Pages 1237-1657, July - August 2004.

I.L. Leites, D.A. Sama, N. Lior. The theory and practice of energy saving in the chemical industry: some methods for reducing thermodynamic irreversibility in chemical technology processes. Energy, vol. 28, 1, 2003, pp. 55 - 97, with Corrigendum, Energy, 29, 2, 2004, 301-304.

N. Lior, Editor, Special issue of ENERGY from ECOS 2001, The International Congress on Efficiency, Costs, Optimization, Simulation and environmental aspects of energy systems and processes, Istanbul, Turkey, 4-6 July 2001; Energy, Vol. 29, Issue 3, 2004, pp. 307-489.

N. Lior, W. Sarmiento-Darkin, H. S. Al-Sharqawi. The Exergy Fields in Transport Processes: Their Calculation and Use. invited keynote presentation and paper, Proc. ASME - ZSIS International Thermal Science Seminar II, Bled, Slovenia, June 13 - 16, 2004, pp. 155-169.

A. Steinfeld and N. Lior. Editors, special issue of Energy from SolarPACES 2002; Energy, Vol. 29, Issues 5-6, pp. 633-959, 2004.

Hassan S. Al-Sharqawi and Noam Lior.Conjugate computation of transient flow and heat & mass transfer between humid air and desiccant plates and channels. Proc. IMECE'03, 2003 ASME International Mechanical Engineering Congress & Exposition, paper IMECE2003-41890, Washington, D.C., Nov. 16-21, 2003, ASME, NY.

R. Wiberg and N. Lior. Error causes and magnitudes in thermochromic liquid crystal thermometry, paper IMECE2003-42101. Proc. IMECE'03, 2003 ASME International Mechanical Engineering Congress & Exposition, Washington, D.C., Nov. 16-21, 2003, ASME, NY.

Na Zhang and Noam Lior. Configuration analysis of a novel zero CO2 emission cycle with LNG cryogenic exergy utilization, paper IMECE2003-41958, Proc. IMECE'03, 2003 ASME International Mechanical Engineering Congress & Exposition, Washington, D.C., Nov. 16-21, 2003, ASME, NY.

N. Lior. Energy resources: the present situation and possible paths to the future (the conference opening presentation). the Global Watch conference sponsored by Stat Oil Co., 29 August 2003, Norwegian University of Science and Technology, Trondheim, Norway.

N. Lior. The cooling process in gas quenching. invited keynote presentation and paper, Proc. International Conference on Advances in Materials and Processing Technology, AMPT 2003, Vol. 1, pp. 171-179, July 2003, Dublin, Ireland (accepted for publication in J. Materials Processing Technol.).

O. Macchion N. Lior and A. Rizzi. Computational Study of velocity distribution and pressure drop for designing gas quench chamber and furnace ducts. AMPT 2003, Proc. Int. Conf. Advances in Materials and Processing Technologies, Vol. 1, pp. 155-158, 8-11 July 2003, Dublin, Ireland.

N. Lior. Water Resources, and the Science and Technology for their Enhancement and Preservation. invited keynote presentation at the 2d UNESCO sponsored Conference on Sustainable Development of Energy, Water and Environment Systems, 15-20 June 2003, Dubrovnik, Croatia.

N. Lior and H. S. Al-Sharqawi. Exergy analysis of flow dehumidification by solid desiccants, presented in International conference on the occasion of Lars Onsager's 100th birthday: transport, dissipation, and turbulence. Trondheim, Norway, June 1-5, 2003.


Na Zhang and Noam Lior. A novel near-zero emission thermal cycle with LNG cryogenic exergy utilization. Proc. ECOS 2003, Vol. 3, pp. 1467-1478, June 30-July 2, 2003, Copenhagen, Denmark.

Jérôme Ferrari, Noam Lior, Jan Slycke. An evaluation of gas quenching of steel rings by multiple-jet impingement. J. Materials Processing Technol., Volume 136, Issues 1-3 , 10 May 2003, Pages 190-201.

W. Fratzscher, K. Stephan and N. Lior, Editors. Special issue of Energy from Strategies of Waste Energy Usage: Belin-Brandenburg Academy of Sciences Conference Dec 1999; Energy, Vol. 28, Issue 13, 2003, pp. 1279-1374.

N. Lior. Energy resources: the present situation and possible paths to the future. invited paper, Gordon Conference on Modern Developments in Thermodynamics, Il Ciocco, Italy, May 2003.

A.M. Alklaibi and N. Lior. Status and potential for membrane-distillation desalination. Proc. IDA World Congress on Desalination and Water Reuse, Bahamas, March 2003, International Desalination Association, Topsfield, MA, USA.

M. Vynnycky, J. Ferrari, and N. Lior. Some Analytical And Numerical Solutions to Inverse Problems Applied to Phase-Transformation Tracking Gas Quenching. ASME J. Heat Transfer, vol. 125, 1, 2003, pp. 1-10.

N. Ipek , N. Lior , F. Bark , A. Eklund, A. Alemany. A simple analytical model for predicting some features of the electrolytic steel-pickling process. Russian Journal of Electrochemistry, vol. 38, 3, 2002, pp. 238-246.

M. Ishida, G. Tsatsaronis, M.J. Moran, H. Kataoka and N. Lior. Editors, Special issue of Energy Conversion and Management from ECOS '99; Energy Conversion and Management J., Vol. 43, Nos. 9-12, 2002, pp. 1121-1581.

Jérôme Ferrari, Noam Lior, Jan Slycke. Gas quenching of steel rings by jet impingement. Proc. ASM International 2002 IFHTSE/ISEC 13th International Federation for Heat Treatment and Surface Engineering Congress, October 7-10, 2002, Columbus, Ohio.

N. Lior. Thoughts about future power generation systems and the role of exergy analysis in their development. Energy Conversion and Management J., vol. 43, 2002, pp. 1187-1198.

N. Lior. The state and perspectives of research in the energy field. invited keynote paper, The Third International Biennial Workshop "Advances in Energy Studies: Reconsidering the Importance of Energy, pp. 351-364, Porto Venere, Italy, 24-28 September 2002.

N. Lior. Water Demand and Water Desalination Technologies/ invited keynote lecture and paper, Dubrovnik 2002 Conference on "Sustainable Development of Energy, Water and Environmental Systems", June 2-7, 2002, Dubrovnik, Croatia.

A. Klaibi and N. Lior. Transport analysis in membrane distillation. Proc. IDA World Congress on Desalination and Water Reuse, Manama, Bahrain, March 2002; International Desalination Association, Topsfield, MA, USA.

N. Lior, R. Chung, and O. Miyatake. Correlations (updated) for predicting the flow through MSF plant inter-stage orifices. Desalination, vol. 151, 2002, pp. 209-216.

Takahisa Yamamoto, Tomohiko Furuhata, Norio Arai, and Noam Lior.Analysis of a high efficiency-low emissions "Chemical Gas Turbine" system. AIAA J. Propulsion & Power, Vol. 18, pp. 432-439, 2002.


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Honghui Lu

Assistant Professor of Computer and Information Science
Email: hhl at seas.upenn.edu
Personal Website

Research Interests:
Large scale distributed systems, high-performance applications, server architecture, networking. Dr. Lu's research has resulted in an innovative combination of compile-time and run-time methods that yields much better performance for practical multiprocessing across Networks of Workstations (NOW) than previous approaches; this work has already deeply affected standard practice.

Selected Recent Publications:
Jin Chen, Wu Baohua, Margaret Delap, Bjorn Knuttson, Honghui Lu, and Cristiana Amza. Locality Aware Dynamic Load Management for Massively Multiplayer Games. ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming (PpoPP), June 2005, Chicago, Illinois.

Yun Mao, Bjorn Knuttson, Honghui Lu and Jonathan M. Smith. Distributed Home Agent for Robust Mobile Access (DHARMA). INFOCOM 2005, March 2005, Miami, Florida.

M. DeLap, B. Knutsson, H. Lu, O. Sokolsky, U. Sammapun, I. Lee and C. Tsarouchis. Is Runtime Verification Applicable to Cheat Detection? Netgames '04, August 2004, Portland, Oregon.

Bjorn Knutsson, Honghui Lu, Wei Xu and Bryan Hopkins. Peer-to-Peer Support for Massively Multiplayer Games. INFOCOM 2004, March 2004, Hong Kong, China.

Honghui Lu, Björn Knutsson, Margaret Delap, John Fiore and Baohua Wu. The Design of Synchronization Mechanisms for Peer-to-Peer Massively Multiplayer Games. Penn CIS Tech Report MS-CIS-04-xy.pdf, 2004.

Bjorn Knutsson, Honghui Lu, Jeffrey Mogul and Bryan Hopkins. Architecture and Performance of Server-Directed Transcoding. ACM Transactions on Internet Technology Vol. 3, No. 4, November 2003, pages 1-33.

Yun Mao, Bjorn Knutsson, Honghui Lu and Jonathan M. Smith. Distributed Home Agent for Robust Mobile Access (DHARMA).Work in Progress Reports, SOSP '03.

Bjorn Knutsson, Honghui Lu, and Jeffrey Mogul, Architecture and Pragmatics of Server-Directed Transcoding. Proceedings of the 7th International Web Content Caching and Distribution Workshop, pp. 229-242, August 2002.

Wei Xu and Honghui Lu. Supporting Massively Multiplayer Games with Peer-to-Peer Systems. Work in Progress Reports, OSDI '02.


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Jennifer R. Lukes

William K. Gemmill Term Assistant Professor of Mechanical Engineering and Applied Mechanics
Email: jrlukes at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Nanoscale thermal, fluid, and mass transport; molecular dynamics simulation; laser-based materials characterization; field-directed patterning for nanofabrication; flow measurement in confined geometries; micro- and nanoscale engineering.

Selected Recent Publications:

J. R. Lukes and C.-L. Tien, 2004, "Molecular Dynamics Simulation of Thermal Conduction in Nanoporous Thin Films," Microscale Thermophysical Engineering, Vol. 8, pp. 341-359.

H. Zhong and J. R. Lukes, 2004, "Thermal Conductivity of Single-Wall Carbon Nanotubes," Proceedings of the 2004 International Mechanical Engineering Congress and Exposition, Anaheim, California, IMECE2004-61665.

Y. Chen, D. Li, J. Yang, Y. Wu, J. R. Lukes, and A. Majumdar, 2004, "Molecular Dynamics Study of the Lattice Thermal Conductivity of Kr/Ar Superlattice Nanowires," Physica B, Vol. 349, pp. 270-280.

Y. Chen, J. R. Lukes, D. Li, J. Yang, and Y. Wu, 2004, "Thermal Expansion and Impurity Effects on Lattice Thermal Conductivity of Solid Argon," Journal of Chemical Physics, Vol. 120, pp. 3841-3846.

Y. Chen, J.-G. Weng, J. R. Lukes, A. Majumdar, and C.-L. Tien, 2001, Molecular Dynamics Simulation of the Meniscus Formation between Two Surfaces. Applied Physics Letters, Vol. 79, pp. 1267-1269.


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David E. Luzzi

Professor of Materials Science and Engineering
Email: luzzi at seas.upenn.edu
Personal Website

Research Interests:
Material structure/property relationships at nanometer-length scales; carbon nanotubes; intermetallic compounds and composites; interfaces: structure, diffusion, phase transformations and mechanical properties; electron microscopy.

Selected Recent Publications:
Jaroenapibal, P; Chikkannanavar, SB; Luzzi, DE; Evoy, S. Nanomechanical resonance studies of carbon nanotube peapod bundles. JOURNAL OF APPLIED PHYSICS, 98 (4): Art. No. 044301 AUG 15 2005.

S.B. Chikkannanavar, S. Paulson, A.T. Johnson and D.E. Luzzi. Synthesis of Peapods Using Substrate Grown Single Wall Carbon Nanotubes: An Enabling Step Towards Peapods Devices. Nano Ltrs, v 5, n 1, January 2005, p 151-155.

S. Evoy, M. Riegelman, N. Naguib, H. Ye, P. Jaroenapibal, D.E. Luzzi and Y. Gogotsi Dielectrophoretic Assembly of Carbon Nanotube Nanoelectromechanical Devices. IEEE Transactions On Nanotechnology, 2004.

P. Jaroenapibal. D.E. Luzzi, S. Evoy, et al. Transmission-electron-microscopic studies of mechanical properties of single-walled carbon nanotube bundles. Applied Physics Letters: 85(19), November 2004.

I.V. Rubtsov. R.M. Russo, T. Albers, et al. Visible and near-infrared excited-state dynamics of single-walled carbon nanotubes. Applied Physics A-Materials Science and Processing, 79(7), 1747-1751, November 2004.

B.W. Smith, D.E. Luzzi, and G.P. Adams. Rhenium oxide nanoparticles for the targeted radiotherapy of solid tumors. Abstracts of the Papers of the American Chemical Society, 228, 2004.

P. Jaroenapibal, D.E. Luzzi, and S. Evoy. In-situ Nanomechanical Studies of Carbon Nanotube Bundles. Conference on Nanotechnology, 2004.

Luzzi, David E. Synthesis, processing, and characterization of filled and unfilled carbon nanotubes. Abstracts of Papers, 227th ACS National Meeting, Anaheim, CA, United States, March 28-April 1, 2004, IEC-218.

Russo, Richard M., Deria, Pravas, Rubtsov, Igor, Therien, Michael J., Luzzi, David E.. Production and characterization of suspensions of single-wall carbon nanotubes. Abstracts of Papers, 227th ACS National Meeting, Anaheim, CA, United States, March 28-April 1, 2004, IEC-219.

Sloan, Jeremy, Luzzi, David E., Kirkland, Angus I., Hutchison, John L., Green, Malcolm L.H. Imaging and Characterization of Molecules and One-Dimensional Crystals Formed within Carbon Nanotubes. MRS Bulletin, v 29, n 4, April, 2004, p 265-271+240-243.

Hernandez, E., Meunier, V., Smith, B.W., Rurali, R., Terrones, H.,Nardelli, M.B., Terrones, M., Luzzi, D.E., Charlier, J.-C. Fullerene coalescencein nanopeapods: a path to novel tubular carbon. Nano Letters, v 3, n 8, Aug. 2003, p 1037-42.

Johnson, A. T., Paulson, S., Chikkanavar, S. B., Radosavljevic, M.,Freitag, M., Thadani, K. V., Kalinin, S. V., Bonnell, D. A., Luzzi, D. E. Carbonnanotube electronics: The "inside story". Proceedings -Electrochemical Society, 2003-15(Fullerenes--Volume 13: Fullerenes and Nanotubes), 258-263, 2003.

Kuzmany, H., Pfeiffer, R., Kramberger, C., Pichler, T., Liu, X.,Knupfer, M., Fink, J., Kataura, H., Achiba, Y., Smith, B.W., Luzzi, D.E. Analysis of the concentration of C60 fullerenes in single wall carbon nanotubes. Applied Physics A: Materials Science and Processing, v 76, n 4, March, 2003, p 449-455.

Luzzi, David E.. Synthesis, structure, and properties of fullerene and nonfullerene nanopeapods. Abstracts of Papers, 225th ACS National Meeting, New Orleans, LA, United States, March 23-27, 2003, COLL-370.

Pan, Ling, Luzzi, David E. Microscopic and Quantitative Investigations on PST Ti-Al/Ti Reaction Diffusion Couples. Materials Research Society Symposium - Proceedings, v 753, 2003, p 187-192.

L. Pan and D. E. Luzzi. Microstructure Evolution In Polysynthetically Twinned (PST) Ti-Al/Ti Diffusion Couples. Phil. Mag., 2003, NSF #DMR96-15228, Penn NSF MRSEC # DMR 00-79909 and NSF # DMR 94-13550, 2003.

Satishkumar, B.C., Taubert, A., Luzzi, D.E. Filling single-wall carbon nanotubes with d- and f-metal chloride and metal nanowires. Journal of Nanoscience and Nanotechnology, v 3, n 1-2, Feb.-April 2003, p 159-63.

Won-Yong Kim, Luzzi, D.E., Pope, D.P. Room temperature deformationbehavior of the Hf-V-Ta C15 Laves phase. Intermetallics, v 11, n 3, 2003, p 257-67.

Chikkannanavar, Satishkumar B., Smith, Brian W., Russo, Richard M., Stercel, Ferenc, Luzzi, David E. Processing of single wall carbon nanotubes and implications for filling experiments. Materials Research Society Symposium - Proceedings, v 706, 2002, p 29-34.

Chikkannanavar, S.B., Taubert, A., Luzzi, D.E. Filling single wall carbon nanotubes with metal chloride and metal nanowires and imaging with scanning transmission electron microscopy. Making Functional Materials with Nanotubes. Symposium (Materials Research Society Symposium Proceedings Vol.706), 2002, p 205-10.

Hornbaker, D. J., Kahng, S.-J., Misra, S., Smith, B. W., Johnson, A. T.,Mele, E. J., Luzzi, D. E., Yazdani, A. Mapping the one-dimensional electronic states of nanotube peapod structures. Science (Washington, DC, UnitedStates), 295(5556), 828-831, 2002.

Kane, C.L., Mele, E.J., Johnson, A.T., Luzzi, D.E., Smith, B.W.,Hornbaker, D.J., Yazdani, A. Theory of scanning tunneling spectroscopy of fullerene peapods. Physical Review B (Condensed Matter and Materials Physics), v 66, n 23, 15 Dec. 2002, p 235423-1-15.

Kimura, Y., Luzzi, D.E., Pope, D.P. Deformation twinning in a HfV/sub 2/+Nb- based Laves phase alloy. Materials Science & Engineering A (Structural Materials: Properties, Microstructure and Processing), v A329-331, 2002, p 241- 8.

Pfeiffer, R., Pichler, T., Holzweber, M., Plank, W., Kuzmany, H.,Kataura, H., Luzzi, D. E.. Concentration of C60 molecules in SWCNT. AIP Conference Proceedings, 633( Structural and Electronic Properties of Molecular Nanostructures), 108-112, 2002.

Smith, B.W., Russo, R.M., Chikkannanavar, S.B., Luzzi, D.E. High-yield synthesis and one-dimensional structure of C/sub 60/ encapsulated in single- wall carbon nanotubes. Journal of Applied Physics, v 91, n 11, 1 June 2002, p 9333-40.

Smith, B.W., Russo, R.M., Chikkannanavar, S.B., Stercel, F., Luzzi, D.E.Reproducible synthesis of C/sub 60/@SWNT in 90% yields. Making Functional Materials with Nanotubes. Symposium (Materials Research Society Symposium Proceedings Vol.706), 2002, p 67-72.

Smith, Brian W., Russo, Richard M., Stercel, Ferenc, Luzzi, David E.,Chikkannanavar, S.B. Structure and properties of C60@SWNT. Materials Research Society Symposium - Proceedings, v 706, 2002, p 193-198.

Stercel, F., Nemes, N.M., Fischer, J.E., Luzzi, D.E. Single wall carbon nanotubes filled with metallocenes: a first example of nonfullerene peapods. Making Functional Materials with Nanotubes. Symposium (Materials Research Society Symposium Proceedings Vol.706), 2002, p 245-50.

Vavro, J., Llaguno, M.C., Satishkumar, B.C., Luzzi, D.E., Fischer, J.E.Electrical and thermal properties of C/sub 60/-filled single-wall carbon nanotubes. Applied Physics Letters, v 80, n 8, 25 Feb. 2002, p 1450-2.

Vavro, J., Llaguno, M.C., Satishkumar, B.C., Haggenmueller, R., Winey, K.I., Luzzi, D.E., Fischer, J.E., Sumanasekera, G.U., Eklund, P.C. Electrical and thermal properties of C/sub 60/-filled single wall carbon nanotubes. AIP Conference Proceedings, n 633, 2002, p 127-30.

Yazdani, Ali, Hornbaker, D. J., Khang, S.-J., Misra, S., Smith, B. W., Luzzi, D. E., Johnson, A. T., Mele, E. J. Spatial modulation of electronic states in nanoscopic peapods. Proceedings - Electrochemical Society, 2002-12 (Fullerenes--Volume 12: The Exciting World of Nanocages and Nanotubes),460- 465, 2002.


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Edward J. Macarak

Professor of Bioengineering; Chairman and Associate Professor of Anatomy and Cell Biology; School of Dental Medicine
Email: macarak at biochem.dental.upenn.edu
Personal Website

Research Interests:
Our laboratory studies genes that are mechanically sensitive and uniquely activated by forces. Using cell models of vascular endothelium and smooth muscle, vascular cell response to stretch and the identification of genes that uniquely respond when cells are mechanically deformed is being carried out. An example of such a gene is the Platelet Activation Factor receptor (PAFr) whose expression is increased in response to mechanical stretch. Additional models of mechanically sensitive tissues that are currently being studied include the urinary bladder and the periodontal ligament. We are investigating, using targeted PCR based techniques, extracellular matrix gene activation and the role of specific transcription factors in mediating alteration in gene expression. An additional area of interest is the role of a chemically engineered heparin mimic, Beta Cyclodestrix Sulfate (BCDS). The goal of these studies is to understand the mechanism by which simple alterations in the chemical structure of BCDS can alter its angiostatic or angiogenic properties.

Selected Recent Publications:
Wei, W.J., Macarak, E.J., Kogan, B.A., et al. Apoptosis/mitosis are required for force-depended fetal bladder development. Journal of Urology, 173(4), April 2005, p 37-38.

Tamura, I., Chaqour, B., Howard, P.S., et al. Effect of IGFs on the expression of EGR-1 and –2 in human periodontal ligament fibroblasts. Molecular Biology of the Cell 15, November 2004, p 368A-369A.

Macarak, E.J., Wei, W., Kogan, B.A., et al. Urinary diversion alters gene expression in fetal sheep bladders. Journal of Urology, 171(4), April 2004, p 45.

Macarak,E.J., Zderic, S.A., Ninomiya, Y., et al. Smooth muscle trans-membrane sarcoglycan complex in partial bladder outlet obstruction. Journal of Urology, 171(4), April 2004, p 455-455.

He, Y., Macarak, E.J., Korostoff, J.M., Howard, P.S. Compression and tension: differential effects on matrix accumulation by periodontal ligament fibroblasts in vitro. Connective Tissue Research, 45(1), 2004, p 23-39.

Kirsch, A.J., Macarak. E.K., et al. Molecular response of the bladder to obstruction. Advances in Experimental Medicine & Biology, 539 (Pt. A), 2003, p 195-216.

Coplen, D.E., Macarak, E.J., and Howard, P.S. Matrix synthesis by bladder smooth muscle cells is modulated by stretch frequency. In Vitro Cellular & Developmental Biology, Animal, 39(3-4), March-April 2003, p 157-62.

Stanton, M.C., Clement, M., Macarak, E.J., Zderic, S.A., and Moreland, R.S. Partial bladder outlet obstruction alters Ca2+ sensitivity of force, but not of MLC phosphorylation, in bladder smooth muscle. American Journal of Physiology-Renal Fluid and Electrolyte Physiology, 285(4), October 2003, F703-10.

Tamura, I., Sakaki, T., Chaqour, B., Howard, P.S., Ikeo, T., and Macarak, E.J. Correlation of P-cadherin and beta-catenin expression and phosphorylation with carcinogenesis in rat tongue cancer induced with 4-nitroquinoline 1-oxide. Oral Oncology, 39(5), July 2003, p 506-14.

Matsumoto, S., Kogan, B.A., Levin, R.M., Howard, P.S., Macarak, E.J. Response of the fetal sheep bladder to urinary diversion. Journal of Urology, February 2003, p 735-9.

Cavalcant-Adam, E.A., Shapiro, I.M., Composto, R.J., Macarak, E.J., and Adams, C.S. RGD peptides immobilized on a mechanically deformable surface promote osteoblast differentiation. Journal f Bone and Mineral Research, 17(12), December 2002, p 2130-40.


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Mitchell Marcus

Professor of Computer and Information Science; RCA Professor of Artificial Intelligence
Email: mitch at cis.upenn.edu
Personal Website

Research Interests:
Statistical natural language processing, computational theories of grammar, cognitive science.

Selected Recent Publications:

Marcus, Mitchell. The 2003 Benjamin Franklin Medal in computer and cognitive science presented to John McCarthy (Stanford California). John McCarthy's multiple contributions to the foundations of artificial intelligence and computer science. Journal of the Franklin Institute, v 341, n 3, May, 2004, p 215-221.

Hewett, Thomas T., Marcus, Mitchell The case for a Benjamin Franklin medal in computer and cognitive science for Marvin L. Minsky. Journal of the Franklin Institute, v 339, n 3, May, 2002, p 295-302.

Marcus, Mitch .The 2001 Bower Award for business leadership presented to Irwin Mark Jacobs. Journal of the Franklin Institute, v 339, n 3, May, 2002, p 277-281.


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Susan S. Margulies

Professor of Bioengineering; Member of the Institute for Medicine and Engineering
Email: margulies at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Cells within the body routinely tolerate deformations during activities such as head turning and breathing, yet when cells are deformed beyond a safe limit or injury threshold, function and structure are altered temporarily or even permanently. Our goal is to determine functional and structural injury thresholds in the brain and lung, and use them to understand mechanisms of traumatic brain and lung injury. In addition, our study of the biochemical and molecular biology of injured cells facilitates the development of preventive and therapeutic measures. Because human tissues tend to be inhomogeneous, anisotropic and nonlinear, and the tissues of interest undergo large strains, determining the complex relationship between cellular and macroscopic responses requires an integrated biomechanics approach consisting of several simultaneous rigorous engineering experimental and theoretical analyses. Tissue mechanical properties and injury thresholds are measured and used to develop computational models. These models are used to generalize our experimental cell and tissue findings and determine macroscopic injury mechanisms. Applications of current work are in the areas of traumatic head injury in adults and children, and ventilator-induced lung injury. These studies parallel clinical investigations regarding the treatment and detection of traumatic injury.

Selected Recent Publications:
Coats B, Margulies SS. Material properties of porcine parietal cortex. J Biomech. 2005 Sep 6.

Patel, AS; Reigada, D; Mitchell, CH; Bates, SR; Margulies, SS; Koval, M. Paracrine stimulation of surfactant secretion by extracellular ATP in response to mechanical deformation. AMERICAN JOURNAL OF PHYSIOLOGY-LUNG CELLULAR AND MOLECULAR PHYSIOLOGY, 289 (3): L489-L496 SEP 2005.

Cavanaugh KJ and Margulies SS. Stretch increases alveolar epithelial permeability to uncharged tracers. Am Rev Resp Crit Care Med (in review)

Arbogast, K.B., Margulies, S.S., Christian, C.W. Initial neurologic presentation in young children sustaining inflicted and unintentional fatal head inuries. Pediatrics, 116(1), July 2005, p 180-184.

Gefen, A., Gefen, N., Linder-Ganz, E., et al. In vivo muscle stiffening under bone compression promotes deep pressure sores. Journal of Biomechanical Engineering-Transactions of the ASME, 127(3), June 2005, p 512-524.

Johnson KR, Zahir N, Alston-Mills B, Reid, S. Gasser, D., Gefen A, Margulies S, Weaver VM. Extracelluar matrix stiffness synergizes with ErbB2 to promote malignant transformation of the breast. Molecular Biology of the Cell, 15: 301A-301A 1666 Suppl. S. November 2004.

Fisher JL, Levitan I, and Margulies SS. Plasma membrane surface increases with tonic stretch of alveolar epithelial cells. Am. J. Resp. Cell Mol Biol, 31(2), August 2004, 200-8.

Raghupathi, R., Mehr, M.F., Helfaer, M.A., and Margulies, S.S. Traumatic axonal injury is exacerbated following repetitive closed head injury in the neonatal pig. Journal of Neurotrauma, 21(3), March 2004, p 307-16.

Ji, S., Dougherty, L., and Margulies, S.S. In vivo measurements of human brain displacement. Proc. Of 48th Stapp Car Crash Conference, SAE, 2004.

Zhu, Q., Prange, MM, and Margulies, S.S. Development and validation of pediatric axonal tissue injury threshold. Proc. Of 48th Stapp Car Crash Conference, SAE, 2004.

Gefen A and Margulies SS. Are in vivo and in situ brain tissues mechanically similar? J Biomech, 2004, 37:1339-1352.

Raghupathi R, Mehr MF, Helfaer MA, and Margulies SS. Increases in regional axonal injury following repetitive closed head injury in the neonatal pig. J Neurotrauma, 2004, 21:307-316.

Gefen A. Gefen N. Zhu Q. Raghupathi R. Margulies SS. Age-dependent changes in material properties of the brain and braincase of the rat. Journal of Neurotrauma. 20(11):1163-77, 2003 Nov.

Prange MT, Coats B, Duhaime AC and Margulies SS. Anthropomorphic simulations of falls, shakes and inflicted impacts for infants. J Neurosurg. 2003, 99: 143-150.

Cavanaugh KJ and Margulies SS. Measurement of stretch-induced loss of alveolar epithelial barrier integrity with a novel in vitro method. Am J Physiol Cell 2002, 283:1801-C1808.

Fisher J and Marguilies SS. Na+-K-ATPase activity in alveolar epithelial cells increases with cyclic stretch. J. Appl Physiol. 2002, 283: L737-L746.

Margulies, S.S, Cavanaugh, K.J., Fisher, J.L. Lung inflation: Can you get too much of a good thing? Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings, v 2, 2002, p 1470-1471.

Prange MT and Margulies SS. Regional, directional and age-dependent properties of brain undergoing large deformation. J Biomed Eng. 2002, 124:244-252.

Raghupathi R and Margulies SS. Traumatic axonal injury after closed head injury in the neonatal pig. J Neurotrauma 2002, 19:843-853.


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Milo M. K. Martin

Assistant Professor of Computer and Information Science
Email: milom at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
My research area of expertise is computer architecture; however, my interests include many aspects of computer systems research (e.g., compilers, security, databases, networking, embedded systems, and distributed systems). I'm a member of Penn's Computer Architecture and Compilers Group (ACG) and I collaborate with Professors Amir Roth and E. Lewis. My recent research has explored hardware techniques to improve the performance of commercial workloads on shared-memory multiprocessors. A main contribution was the development of a new coherence protocol that decouples correctness from performance. This decoupling reduced complexity while increasing performance and providing robust performance over many workloads and system configurations. Finally, this new protocol enabled the deployment of a wide range of optimizations by reducing the complexity of their implementations.


Selected Recent Publications:
Milo M.K. Martin. Formal Verification and Its Impact on the Snooping versus Directory Protocol Debate. International Conference on Computer Design (ICCD), October 2005.

Colin Blundell, E Christopher Lewis, and Milo M.K. Martin. Deconstructing Transactional Semantics: The Subtleties of Atomicity. Workshop on Duplicating, Deconstructing, and Debunking (WDDD), June 2005.

Michael R. Marty, Jesse D. Bingham, Mark D. Hill, et al. Improving Multiple-CMP Systems Using Token Coherence. International Symposium on High Performance Computer Architectures, February 2005.

Sebastian Burckhardt, Rajeev Alur, and Milo M.K. Martin. Verifying Safety of a Token Coherence Implementation by Parametric Compositional Refinement. Sixth International Conference on Verification, Model Checking and Abstract Interpretation, January 2005.

Daniel J. Sorin, , Mark D. Hill, and David A. Wood. Using Speculation to Simplify Multiprocessor Design. International Parallel and Distributed Processing Symposium (IPDPS), April 2004.

Milo M.K. Martin, Mark D. Hill and David A. Wood. Token Coherence: A New Framework for Shared-Memory Multiprocessors. IEEE Micro, November-December 2003.

Milo M. K. Martin, Pacia J. Harper, Daniel J. Sorin, Mark D. Hill, and David A. Wood. Using Destination-Set Prediction to Improve the Latency/Bandwidth Tradeoff in Shared Memory Multiprocessors. International Symposium on Computer Architecture (ISCA), June 2003.

Milo M. K. Martin, Mark D. Hill, and David A. Wood. Token Coherence: Decoupling Performance and Correctness. International Symposium on Computer Architecture (ISCA), June 2003.

Alaa R. Alameldeen, Milo M.K. Martin, Carl J. Mauer, Kevin E. Moore, Min Xu, Daniel J. Sorin, Mark D. Hill and David A. Wood. Simulating a $2M Commercial Server on a $2K PC. IEEE Computer, February 2003.

Daniel J. Sorin, Manoj Plakal, Anne E. Condon, Mark D. Hill, Milo M. K. Martin and David A. Wood. Specifying and Verifying a Broadcast and a Multicast Snooping Cache Coherence Protocol. IEEE Transactions on Parallel and Distributed Systems, June 2002 (vol 13, number 6). (Previously available as Dept. of Computer Sciences Technical Report CS-TR-2000-1412, March 2000.)

Daniel J. Sorin, Milo M. K. Martin, Mark D. Hill, and David A. Wood. SafetyNet: Improving the Availability of Shared Memory Multiprocessors with Global Checkpoint/Recovery. International Symposium on Computer Architecture (ISCA), May 2002.

Alaa R. Alameldeen, Carl J. Mauer, Min Xu, Pacia J. Harper, Milo M.K. Marti, Daniel J. Sorin, Mark D. Hill and David A. Wood. Evaluating Non-deterministic Multi-threaded Commercial Workloads. Workshop On Computer Architecture Evaluation using Commercial Workloads (CAECW), February 2002.

Milo M. K. Martin, Daniel J. Sorin, Mark D. Hill, and David A. Wood. Bandwidth Adaptive Snooping. 8th International Symposium on High Performance Computer Architecture (HPCA), February 2002.


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David F. Meaney

Professor of Bioengineering, Neurosurgery; Member of the Institute for Medicine and Engineering
Email: dmeaney at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:

We are part of a very new field at the intersection between molecular neurobiology and biomedical engineering that we term molecular neuroengineering. Molecular neuroengineering uses the tools of molecular and cell biology,computational biology, and bioengineering to understand how the nervous system works at the single cell and molecular scale. There is tremendous clinical potential for work in this area, since knowing the molecular triggering events within a single cell or small multi-cellular networks will provide the earliest possible targets for treating a disease. We build systems to measure the biochemical and genomic response of single cells or cell networks to controlled stimulation that mimic either physical injury or regeneration in the nervous system. We use data from these measurements to build models of how cells of the nervous system will respond following either an injury or during growth, and we use these models to identify key regulating points in the response of these cells that might be targets for reducing the effects of the injury or, alternatively, paths to stimulate growth. We believe the future treatment of disease will become increasingly reliant on information at this scale in the nervous system, simply because it provides the best time to treat a disease. At a more fundamental level, we will also learn how cells in the nervous system can adapt dynamically under even normal, physiological conditions

Selected Recent Publications:
Longhi, L., Saatman, K.E., Fujimoto, S., et al. Temporal window of vulnerability to repetitive experimental concussive brain injury. Neurosurgery, 56(2), February 2005, p 364-74.

Ledoux, W.R., Meaney, D.F., and Hillstrom, H.J. A quasi-linear, viscoelastic, structural model of the plantar soft tissue with frequeny-sensitive damping properties. Journal of Biomechanical Engineering, v 126, n 6, December 2004, p 831-837.

Lusardi, T.A., Rangan, J., Sun, D., Smith, D.H., and Meaney, D.F. A device to study the initiation and propagation of calcium transients in cultured neurons after mechanical stretcth. Ann. Biomed. Eng., 32(11), November 2004, p 1546-58.

Pfister, B.J., Iwata, A., Meaney, D.F., and Smith, D.H. Extreme stretch growth of integrated axons. J. Neurosci, 24(36), September 2004, p 7978-83.

Pfister, B.P., Huang, J., Zager, E.L., et al. Engineering nerve constructs for clinical application. Journal of Neurotrauma, 21(9), September 2004, p 1288.

DeRidder, M.N., Raghupathi, R., and Meaney, D.F. Effects of ifenpordil on the level of calpain and caspase-3 mediated cell death in the hippocampus. Journal of Neurotrauma, 21(9), September 2004, p 1306.

Schiffman, K.K., Geddes, D.M. and Meaney, D.F. Neuronal response to injury varies depending on both magnitude and directionality of applied stretch. Journal of Neurotrauma, 21(9), September 2004, p 1315.

Miller, W.J. and Meaney, D.F. Mechanically injured astrocytes activate nearby astrocytes through an ATP-mediated pathway in vitro. Journal of Neurotrauma, 21(9), September 2004, p 1316.

Geddes, D.M., and Meaney, D.F. Synaptic NMDA receptors are an initiating factor in the cytosolic calcium response to stretch. Journal of Neurotrauma, 21(9), September 2004, p 1316.

Chen, X.H., Siman, R., Iwata, A., Meaney, D.F., Trojanowski, J.Q., Smith D.H. Long-term accumulation of amyloid-beta, beta-secretase, presenilin-1, and caspasse-3 in damaged axons following brain trauma. Am. J. Pathol, 165(2), August 2004, p 357-71.

Davis JE, Eberwine JH, Hinkle DA, et al. Methodological considerations regarding single-cell gene expression profiling for brain injury. NEUROCHEMICAL RESEARCH 29 (6): 1113-1121 JUN 2004.

Iwata A, Stys PK, Wolf JA, et al. Traumatic axonal injury induces proteolytic cleavage of the voltage-gated sodium channels modulated by tetrodotoxin and protease inhibitors. JOURNAL OF NEUROSCIENCE 24 (19): 4605-4613 MAY 12 2004.

Lusardi TA, Wolf JA, Putt ME, et al. Effect of acute calcium influx after mechanical stretch injury in vitro on the viability of hippocampal neurons. JOURNAL OF NEUROTRAUMA 21 (1): 61-72 JAN 2004.

Bain, Allison C., Shreiber, David I., Meaney, David F. Modeling of Microstructural Kinematics during Simple Elongation of Central Nervous System Tissue. Journal of Biomechanical Engineering, v 125, n 6, December, 2003, p 798-804.

Lusardi TA, Smith DH, Wolf JA, et al.The separate roles of calcium and mechanical forces in mediating cell death in mechanically injured neurons. BIORHEOLOGY 40 (1-3): 401-409 Sp. Iss. SI 2003.

Pfister BJ, Iwata A, Meaney DF, et al. Engineering nerve constructs in vitro. JOURNAL OF NEUROTRAUMA 20 (10): P124 OCT 2003.

Taylor A, Liu G, Meaney D. Temporal profile of differential gene expression following glutamate exposure in cultured hippocampal neurons. JOURNAL OF NEUROTRAUMA 20 (10): P339 OCT 2003.

Saatman KE, Abai B, Grosvenor T, et al. Traumatic axonal injury results in biphasic calpain activation and retrograde transport impairment in mice. JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 23 (1): 34-42 JAN 2003.

Marciano PG, Eberwine JH, Ragupathi R, et al. Expression profiling following traumatic brain injury: A review. NEUROCHEMICAL RESEARCH 27 (10): 1147-1155 OCT 2002.

Smith DH, Meaney DF. Roller coasters, G forces, and brain trauma: On the wrong track? JOURNAL OF NEUROTRAUMA 19 (10): 1117-1120 OCT 2002.


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Max Mintz

Professor of Computer and Information Science
Email: mintz at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
Decision making under uncertainty, stochastic modeling, and multisensor fusion, with applications for multiagent robotic systems.

Selected Recent Publications:

G.Egnal, M. Mintz, and R. P. Wildes. A Stereo Confidence Metric Using Single View Imagery with Comparison to Five Alternative Approaches. Image and Vision Computing, v 22, n 12 SPEC. ISS., October 1 2004, p 943-957.

R. Alur, C. Belta, V. Kumar, M. Mintz, G. Pappas, H. Rubin, and J. Schug. Modeling and Analyzing Biomolecular Networks. Computing in Science and Engineering. Vol. 4(1), pp. 20-31, 2002.

G. Egnal, M. Mintz, and K. Daniilidis. Limiting the Search Range of Correlation Stereo Using Silhouettes. CIPPRS/IAPR International Conference on Vision Interface, May 2002.

G. Egnal, M. Mintz, and R. P. Wildes. A Stereo Confidence Metric Using Single View Imagery. CIPPRS/IAPR International Conference on Vision Interface, May 2002.


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Steven Nicoll

Assistant Professor of Bioengineering and Orthopaedic Surgery; Member of the Institute for Medicine and Engineering
Email: nicoll at seas.upenn.edu
Personal Website

Research Interests:
Epigenetic Control of Cellular Phenotype: Recent advances in tissue engineering have increased the need for specialized cell populations to promote tissue regeneration. Embryonic stem cells have been investigated for such applications and hold great therapeutic promise. However, practical and ethical considerations may ultimately limit the widespread use of such progenitor cells. Our approach involves the conversion of skin cells, specifically human dermal fibroblasts, to specialized cell types by regulating environmental cues such as oxidative and mechanical stresses that govern cell differentiation. Thus far, we have successfully induced dermal fibroblasts to differentiate into chondrocytes (i.e., cartilage cells) and are currently using these cells to engineer articular cartilage. We are extending these studies to explore whether such fibroblasts may give rise to other cell types (i.e., bone and muscle-forming cells) by modulation of similar epigenetic pathways. Biomimetic Scaffolds for Connective Tissue Repair: The success of implantable materials depends heavily upon their ability to integrate with surrounding host tissue. The incorporation of growth factors into carrier materials as well as the immobilization of bioactive peptides which mimic the cell binding domains of extracellular matrix macromolecules are current approaches that we use to promote cell adhesion and improve implant fixation and stability. A particular class of collagen mimetic peptides has been shown to stimulate cell attachment and differentiation on clinically relevant biomaterials. The interaction of these collagen-like peptides with cell surface receptors and their potential to generate precise, three-dimensional cellular architectures are being characterized on materials used in the development of living tissue surrogates. Transcriptional and Genetic Determinants of Chondrogenesis: We utilize an in vitro model system for cartilage differentiation developed in our laboratory to explore signal transduction pathways and identify novel genes involved in chondrogenesis. Expanding on previous work with the transforming growth factor-ß (TGF-ß) family of polypeptide cytokines, we study the role of transcription factors that act downstream of pathways mediated by TGF-ß family members. In addition, we are attempting to isolate regulatory genes essential to cartilage formation using a variety of techniques including differential display reverse-transcription-PCR and gene microarray analyses. Cloning of such genes may result in the discovery of novel growth and morphogenetic factors that may be of use in clinical orthopaedics.

Selected Recent Publications:
Hee, C.K., Jonikas, M.A., and Nicoll, S.B. Influence of three-dimensional scaffold on the expression of osteogenic differentiation markers by human dermal fibroblasts. Biomaterials, in press, 2005.

Brink, H.E., Stalling, S. S. and Nicoll, S.B. Influence of serum on fetal and adult dermal fibroblast migration, adhesion and collagen expressin. In Vitro Cell. Dev. Biol., in press, 2005.

Wheaton, A.J., Corbo, M.T., Elliott, D.M., et al. Noninvasive measurement of cartilage biomechanics using T-1 beta MRI. Osteoarthritis and Cartilage 12: S21-S21 Suppl. B 2004.

Basalo, I.M., Mauck, R.L., Kelly, T.N., et al. Cartilage interstitial fluid load support in unconfined compression following enzymatic digestion. Journal of Biomechanical Engineering, v 126, n 6, December 2004, p 779-786.

Hee, C.K., Jonikas, M.A., and Nicoll, S.B. Influence of three-dimensional scaffold on osteogenic differentiation of human dermal fibroblasts. Transactions, 7TH World Biomaterials Congress, 2004, p 450.

Park S. Krishnan R. Nicoll SB. Ateshian GA. Cartilage interstitial fluid load support in unconfined compression. Journal of Biomechanics. 36(12):1785-96, 2003 Dec.

Mauck RL. Nicoll SB. Seyhan SL. Ateshian GA. Hung CT. Synergistic action of growth factors and dynamic loading for articular cartilage tissue engineering. Tissue Engineering. 9(4):597-611, 2003 Aug.

Nicoll, S.B., Mauck, R.K., Tsay, R.C., et al. Intermittent hydrostatic pressurization modulates gene expression in human dermal fibroblasts seeded in three-dimensional polymer scaffolds. American Society of Mechanical Engineers, Bioengineering Division BED, v 54, 2002, p 103-104.

Nicoll, S. B., Barak, O., Csóka, A. B., Bhatnagar, R. S. and Stern, R. Hyaluronidases and CD44 undergo differential modulation during chondrogenesis. Biochem Biophys Res Comm, 292:819-825, 2002.


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George Pappas

Associate Professor of Electrical and Systems Engineering; Associate Professor of Computer and Information Sciences; Associate Professor of Mechanical Engineering and Applied Mechanics.
Email: pappasg at ee.seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Hybrid systems, hierarchical control systems, embedded real-time systems, nonlinear systems, geometric control theory, robotics, unmanned aerial vehicles, formation control systems, distributed control of multi-agent systems.

Selected Recent Publications:
Haghverdi, Esfandiar (Departments of ESE and CIS, University of Pennsylvania);
Tabuada, Paulo; Pappas, George J. Bisimulation relations for dynamical, control, and hybrid systems. Theoretical Computer Science, v 342, n 2-3, Sep 7, 2005, p 229-261.

Michael Zavlanos and George J. Pappas. Controlling connectivity of dynamic graphs. IEEE Conference on Decision and Control, Seville, Spain, December 2005, submitted.

Antoine Girard and George J. Pappas. Approximate bisimulations for constrained linear systems. IEEE Conference on Decision and Control, Seville, Spain, December 2005, submitted.

Nicolo Giorgetti and George J. Pappas. Bounded model checking for hybrid dynamical systems. IEEE Conference on Decision and Control, Seville, Spain, December 2005, submitted.

George Fainekos, Hadas Kress-Gazit, and George J. Pappas. Hybrid controllers for path planning: a temporal logic approach. IEEE Conference on Decision and Control, Seville, Spain, December 2005, submitted.

Gianluca Mariottini, George J. Pappas, Domenico Prattichizzo, and Kostas Daniilidis. Vision-based localization of leader-follower formations. IEEE Conference on Decision and Control, Seville, Spain, December 2005, submitted.

Stephen Prajna Ali Jadbabaie, and George J. Pappas. A framework for worst-case and stochastic safety verification using barrier certificates. IEEE Transactions on Automatic Control, March 2005.

George Fainekos, Hadas Kress Gazit, and George J. Pappas. Temporal logic planning for mobile robots. IEEE Conference on Robotics and Automation, Barcelona, Spain, April 2005.

Mohamed Babaali, and George J. Pappas. Observability of switched linear systems in continuous time. Hybrid Systems: Computation and Control, Zurich, Switzerland, March 2005.

Antoine Girard and George J. Pappas. Approximation metrics for discrete and continuous systems. IEEE Transactions on Automatic Control, May 2005, submitted.

Mohamed Babaali and George J. Pappas. Mode observability in switched linear systems. IEEE Transactions on Automatic Control, May 2005, submitted.

Stephen Prajna, Ali Jadbabaie, and George J. Pappas. A framework for worst-case and stochastic safety verification using barrier certificates. IEEE Transactions on Automatic Control, March 2005, submitted.

Herbert Tanner, Ali Jadbabaie, and George J. Pappas. Flocking in fixed and switching networks. IEEE Transactions on Automatic Control, April 2005, submitted.

Esfandiar Haghverdi, Paulo Tabuada, and George J. Pappas. Bisumulation relations for dynamical, control and hybrid systems. Theoretical Computer Science, 2005.

Paulo Tabuada, George J. Pappas, and Pedro Lima. Motion feasibility of multi-agent formations. IEEE Transactions on Robotics, 21(3): 387-392, June 2005.

Paulo Tabuada and George J. Pappas. Quotients of fully nonlinear control systems. SIAM Journal of Control and Optimization, 43(5):1844-1866, 2005.

Paulo Tabuada and George J. Pappas. Hierarchichal trajectory generation for a class of nonlinear systems. Automatica, 41(4): 701-708, April 2005.

Selcuk Bayraktar, Georgios Fainekos, and George J. Pappas. Experimental cooperative control of unmanned aerial vehicles.Submitted to the Proceedings of the 43rd IEEE Conference on Decision and Control, The Bahamas, December 2004.

Stephen Prajna, Ali Jadbabaie, and George J. Pappas. Stochastic safety verification using barrier certificates. Submitted to the Proceedings of the 43rd IEEE Conference on Decision and Control, The Bahamas, December 2004.

Hakan Yazarel, Stephen Prajna, and George J. Pappas. S.O.S. for safety.Submitted to the Proceedings of the 43rd IEEE Conference on Decision andControl, The Bahamas, December 2004.

Volkan Isler, Calin Belta, Kostas Daniilidis, and George J. Pappas. Hybrid control for visibility-based pursuit evasion games. Proceedings of the 2004 IEEE/RSJ International Conference on Intelligent Robots and Systems, Sentai, Japan, September 2004.

Herbert Tanner, George J. Pappas and Vijay Kumar. Leader to formatin stability. IEEE Transactions on Robotics and Automation, 20(3):443-455, June 2004.

Rajeev Alur, Salvatorre La Torre, and George J. Pappas. Optimal paths in weighted timed automata. Theoretical Computer Science, 318(3):297-322, June 2004.

Hakan Yazarel, and George J. Pappas. Geometric programming relaxations for linear system reachability (Finalist,Best Student Paper Award).Proceedings of the 2004 American Control Conference, Boston, MA, June 2004

Paulo Tabuada and George J. Pappas. Bisimilar control affine systems.Systems & Control Letters, 52(1):49-58, May 2004.

Paulo Tabuada, George J. Pappas, and Pedro Lima. Compositional abstractions of hybrid control systems.Discrete Event Dynamic Systems, 14(2):203-238, April 2004.

George J. Pappas. Bisimilar linear systems.Automatica, 39(12):2035-2047, December 2003.

Paulo Tabuada and George J. Pappas. Abstractions of Hamiltonian control systems. Automatica, 39(12):2025-2033, December 2003.

Paulo Tabuada, and George J. Pappas. Finite bisimulations of controllable linear systems. Proceedings of the 42nd IEEE Conference on Decision and Control, Maui, Hawaii, December 2003.

Paulo Tabuada, and George J. Pappas. From discrete specifications to hybrid control. Proceedings of the 42nd IEEE Conference on Decision and Control, Maui, Hawaii, December 2003.

Paulo Tabuada, and George J. Pappas. Hierarchical trajectory generation for a class of nonlinear systems. Proceedings of the 42nd IEEE Conference on Decision and Control, Maui, Hawaii, December 2003.

Herbert Tanner, Ali Jadbabaie, and George J. Pappas. Stable flocking of mobile agents, Part II : Dynamic Topology. Proceedings of the 42nd IEEE Conference on Decision and Control, Maui,Hawaii, December 2003.

Herbert Tanner, Ali Jadbabaie, and George J. Pappas. Stable flocking of mobile agents, Part I : Fixed Topology.Proceedings of the 42nd IEEE Conference on Decision and Control, Maui, Hawaii, December 2003.

Paulo Tabuada and George J. Pappas.From nonlinear to hamiltonian via feedback. IEEE Transactions on Automatic Control, 48(8):1439- 1442, August 2003.

Herbert Tanner, Ali Jadbabaie, and George J. Pappas. Coordination of multiple autonomous vehicles.Proceedings of the 11th IEEE Mediterranean Conference on Control and Automation, Rhodes, Greece, June 2003.

Herbert Tanner, and George J. Pappas. Abstractions of constrained linear systems. Proceedings of the 2003 American Control Conference, Denver, CO, June 2003.

Paulo Tabuada and George J. Pappas. Model checking LTL over controllable linear systems is decidable. Hybrid Systems : Computation and Control, Lecture Notes in Computer Science,volume 2623, Springer, April 2003.

Esfandiar Hagverdi, Paulo Tabuada, and George J. Pappas.Bisimulation relations for dynamical and control systems.In Category Theory and Computer Science (CTCS), Electronic Notes in Theoretical Computer Science, Ottawa, February 2003.

R. Alur, T. Dang, J. Esposito, Y. Hur, F. Ivancic, V. Kumar, I. Lee, P. Mishra, G. J. Pappas, and O. Sokolsky. Hierarchical modeling and analysis of embedded systems.Proceedings of the IEEE, 91(1):11-28, January 2003.

Paulo Tabuada and George J. Pappas. Bisimilar control affine systems.Proceedings of the 41st IEEE Conference on Decision and Control, Las Vegas, NV, December 2002.

Paulo Tabuada and George J. Pappas.Discrete synchronization of hybrid systems. Proceedings of the 41st IEEE Conference on Decision and Control, Las Vegas, NV, December 2002.

Paulo Tabuada and George J. Pappas. From nonlinear to hamiltonian via feedback. Proceedings of the 41st IEEE Conference on Decision and Control, Las Vegas, NV, December 2002.

Herbert Tanner, George J. Pappas, and Vijay Kumar. Input-state-stability on formation graphs. Proceedings of the 41st IEEE Conference on Decision and Control, Las Vegas, NV, December 2002.

R. Fierro, A. Das, J. Spletzer, J. Esposito, V. Kumar, J. Ostrowski, G.Pappas, CJ Taylor, Y. Hur, R. Alur, I. Lee, G. Grudic, and B. Southall. A framework and architecture for multirobot coordination.International Journal of Robotics Research, 21(10-11):977-995 October-November 2002.

Esfandiar Haghverdi, Paulo Tabuada, and George J. Pappas. Unifying bisimulation relations for discrete and continuous systems.Proceedings of the Mathematical Theory of Networks and Systems, Notre Dame,IN, August 2002.

Paulo Tabuada and George J. Pappas. Quotients of fully nonlinear control systems. Proceedings of the Mathematical Theory of Networks and Systems, Notre Dame, IN, August 2002.

Herbert Tanner, George J. Pappas, and Vijay Kumar. Stability properties of interconnected vehiclesProceedings of the Mathematical Theory of Networks and Systems, Notre Dame,IN, August 2002.

Herbert Tanner and George J. Pappas. Formation input-to-state stability. Proceedings of the 15th International Federation on Automatic Control World Congress, Barcelona, Spain, July 2002.

Paulo Tabuada, George J. Pappas, and Pedro Lima. Decentralizing formations of multi-agent systems.Proceedings of the 10th Mediterranean Conference on Control and Automation, Lisbon, Portugal, July 2002.

Herbert Tanner and George J. Pappas. Simulation relations for discrete-time linear systems.Proceedings of the 15th International Federation on Automatic Control World Congress, Barcelona, Spain, July 2002.

Pradyumna Mishra and George J. Pappas. Flying Hot Potatoes.Proceedings of the 2002 American Control Conference, pages 754-759,Anchorage, Alaska, May 2002.

George J. Pappas, and Slobodan Simic. Consistent abstractions of affine control systems. IEEE Transactions on Automatic Control, 47(5):745-756, May 2002.

Herbert Tanner, Vijay Kumar, and George J. Pappas. The effect of feedback and feedforward on formation ISS. Proceedings of the 2002 International Conference on Robotics andAutomation, pages 3448-3453, Arlington, VA, May 2002.

Paulo Tabuada, George J. Pappas, and Pedro Lima. Composing abstractions of hybrid systems. Hybrid Systems : Computation and Control, Lecture Notes in Computer Science, volume 2289, Springer, March 2002.

Rajeev Alur, Calin Belta, Vijay Kumar, Max Mintz, George J. Pappas, Harvey Rubin, and Jonathan Schug. Modeling and analyzing biomolecular networks.Computing in Science and Engineering, 4(1):20-31, January 2002


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Fernando Pereira

Andrew and Debra Rachleff Professor of Computer and Information Science and Chair of the Department of Computer and Information Science
Email: pereira at seas.upenn.edu
Personal Website

Research Interests:
My main research goal is to develop machine-learnable models of language and other natural sequential data such as biological sequences. Penn, with its strong machine learning group, and its deep connections between computer science, linguistics, and computational biology, is the ideal place to pursue those goals. My most recent work has been on finite-state models for text information extraction and speech recognition, but I am also interested in information-theoretic approaches to inducing compact representations of multivariate data, and on bridging the gap between distributional and logical views of natural-language syntax and semantics.

Conditional probability models for information extraction and segmentation: Many sequence-processing problems involve breaking it into subsequences (person name vs other), or labeling sequence elements (parts of speech). Existing probabilistic methods for these tasks, in particular HMMs, have difficulty in dealing with multiple overlapping features of the input sequence. Maximum entropy Markov models were a first approach to this problem, which have now been superseded the more powerful conditional random fields. We are applying these models to information extraction from biomedical text and to gene finding.

Finite-state speech processing: What do regular expressions turn into when we need to assign weights (maybe probabilities) to alternative matches, and to compose pattern matchers? Weighted finite-state transducers. At AT&T, I was involved in developing these as a framework for speech recognition, leading to a creation of a powerful library that has been made available for non-commercial use.

The information bottleneck: How does one quantify the notion of information about something? Given some variables of interest, sources of information about those variables can be compressed while preserving the information about the variables. The tradeoff between compression and information preservation, which we call the information bottleneck, answers the question. Using this model, we can build compact representations of complex relationships, for instance word cooccurrences in text.

Formal semantics of natural language: The syntactic structures of natural-language sentences and their meanings must be linked by a systematic, compositional process for language learning and use to be possible. However, this form of compositionality is more subtle than those used in logical and programming languages. Linear logic turns out to be a good metalanguage to describe the natural-language syntax-semantics mapping.

Selected Recent Publications:
Jeremiah Crim, Ryan McDonald, and Fernando Pereira. Automatically annotating documents with normalized gene lists. BMC Bioinformatics, 6(Supp 1):S13, 2005.

Andrew McCallum, Kedar Bellare, and Fernando Pereira. A conditional random field for discriminatively-trained finite-state string edit distance. In Proceedings of the 21st Conference on Uncertainty in Artificial Intelligence (UAI 2005), 2005.

Ryan McDonald and Fernando Pereira. Identifying gene and protein mentions in text using conditional random fields. BMC Bioinformatics, 6(Suppl 1): S6, 2005.

Ryan McDonald, Koby Crammer, and Fernando Pereira. Online large-margin training of dependency parsers. In 43rd Annual Meeting of the Association for Computational Linguistics (ACL 2005), 2005.

Ryan MdDonald, Fernando Pereira, Seth Kulick, Scott Winters, Yang Jin, and Pete White. Simple algorithms for complex relation extraction with applications to biomedical ie. In 43rd Annual Meeting of the Association for Computational Linguistics (ACL 2005), 2005.

John Blitzer, Kilian Weinberger, Lawrence Saul, and Fernando Pereira. Hierarchical distributed representations for statistical language modeling. In Lawrence K. Saul, Yair Weiss, and Léon Bottou, editors, Advances in Neural Information Processing Systems 17, Cambridge, MA, 2004. MIT Press.

Amir Globerson, Gal Chechik, Fernando Pereira, and Naftali Tishby. Euclidean embedding of co-occurrence data. In Lawrence K. Saul, Yair Weiss, and Léon Bottou, editors, Advances in Neural Information Processing Systems 17, Cambridge Massachusetts, 2004. MIT Press.

David McAllester, Michael Collins, and Fernando Pereira. Case-factor diagrams for structured probabilistic modeling. In Proceedings of the 20th Conference on Uncertainty in Artificial Intelligence, July 2004.

Ryan McDonald and Fernando Pereira. Identifying gene and protein mentions in text using conditional random fields. In Critical Assessment of Text Mining Methods in Molecular Biology. European Molecular Biology Organization, 2004.

Ryan T. McDonald, R. Scott Winters, Mark Mandel, Yang Jin, Peter S. White, and Fernando Pereira. An entity tagger for recognizing acquired genomic variations in cancer literature. Bioinformatics, 2004. To appear.

Fei Sha and Fernando Pereira. Shallow parsing with conditional random fields. In Proceedings of HLT-NAACL 2003, pages 213-220. Association for Computational Linguistics, 2003.

Mehryar Mohri, Fernando Pereira, and Michael Riley. Weighted finite-state transducers in speech recognition. Computer Speech and Language, 16(1):69-88, 2002.


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Benjamin C. Pierce

Professor of Computer and Information Science, CIS Graduate Group Chair
Email: bcpierce at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
Programming languages, type systems, concurrent and distributed programming, process calculi, optimistic data replication.

Selected Recent Publications:
J. Nathan Foster, Michael B. Greenwald, Christian Kirkegaard, Benjamin C. Pierce, and Alan Schmitt. Exploiting Schemas in Data Synchronization. In Database Programming Languages (DBPL), August 2005.

Brian E. Aydemir, Aaron Bohannon, Matthew Fairbairn, J. Nathan Foster, Benjamin C. Pierce, Peter Sewell, Dimitrios Vytiniotis, Geoffrey Washburn, Stephanie Weirich, and Steve Zdancewic. Mechanized metatheory for the masses: The POPLmark Challenge. In International Conference on Theorem Proving in Higher Order Logics (TPHOLs), August 2005.

Michael Y. Levin and Benjamin C. Pierce. Type-based Optimization for Regular Patterns. Technical Report MS-CIS-05-13, University of Pennsylvania, June 2005.

Michael Y. Levin and Benjamin C. Pierce. Type-based Optimization for Regular Patterns. In Database Programming Languages (DBPL), August 2005.

Benjamin C. Pierce. Fancy Types for XML: Friend or Foe?, April 2005. Talk at LINKS workshop, April 2005.

Benjamin C. Pierce. Harmony: The Art of Reconciliation, April 2005. Invited talk at Trusted Global Computing conference, April 2005.

Vladimir Gapeyev, Michael Y. Levin, Benjamin C. Pierce, and Alan Schmitt. XML Goes Native: Run-time Representations for Xtatic. In 14th International Conference on Compiler Construction, April 2005.

J. Nathan Foster, Michael B. Greenwald, Christian Kirkegaard, Benjamin C. Pierce, and Alan Schmitt. Schema-Directed Data Synchronization. Technical Report MS-CIS-05-02, University of Pennsylvania, March 2005. Supercedes MS-CIS-03-42.

Haruo Hosoya, Jérôme Vouillon, and Benjamin C. Pierce. Regular Expression Types for XML. ACM Transactions on Programming Languages and Systems (TOPLAS), 27(1):46-90, January 2005. Preliminary version in ICFP 2000.

Vladimir Gapeyev, Michael Y. Levin, Benjamin C. Pierce, and Alan Schmitt. The Xtatic Compiler and Runtime System, 2005.

Benjamin C. Pierce, editor. Advanced Topics in Types and Programming Languages. MIT Press, 2005.

Michael B. Greenwald, Sanjeev Khanna, Keshav Kunal, Benjamin C. Pierce, and Alan Schmitt. Agreement is Quicker than Domination: Conflict Resolution for Optimistically Replicated Data. Submitted for publication; available electronically, 2005.

J. Nathan Foster, Michael B. Greenwald, Jonathan T. Moore, Benjamin C. Pierce, and Alan Schmitt. Combinators for Bi-Directional Tree Transformations: A Linguistic Approach to the View Update Problem. In ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages (POPL), Long Beach, California, 2005. Extended version available as University of Pennsylvania technical report MS-CIS-03-08. Earlier version presented at the Workshop on Programming Language Technologies for XML (PLAN-X), 2004.

Eijiro Sumii and Benjamin C. Pierce. A Bisimulation for Type Abstraction and Recursion. In ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages (POPL), Long Beach, California, 2005.

Vladimir Gapeyev, Michael Y. Levin, Benjamin C. Pierce, and Alan Schmitt. The Xtatic Experience. In Workshop on Programming Language Technologies for XML (PLAN-X), January 2005. University of Pennsylvania Technical Report MS-CIS-04-24, Oct 2004.

Benjamin C. Pierce. Combinators for Bi-Directional Tree Transformations: A Linguistic Approach to the View Update Problem, October 2004. Invited talk at New England Programming Languages Symposium.

Vladimir Gapeyev and Benjamin C. Pierce. Paths into Patterns. Technical Report MS-CIS-04-25, University of Pennsylvania, October 2004.

Benjamin C. Pierce and Jérôme Vouillon. What's in Unison? A Formal Specification and Reference Implementation of a File Synchronizer. Technical Report MS-CIS-03-36, Dept. of Computer and Information Science, University of Pennsylvania, 2004.

Eijiro Sumii and Benjamin C. Pierce. A Bisimulation for Dynamic Sealing. In ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages (POPL), Venice, Italy, 2004. Full version to appear in Theoretical Computer Science.

Benjamin C. Pierce. Harmony: A Synchronization Framework for Tree-Structured Data, September 2003. Slides from a talk presented in several places (Cambridge, Edinburgh, Philadelphia, Princeton) in Fall 2003.

Haruo Hosoya and Benjamin C. Pierce. XDuce: A Statically Typed XML Processing Language. ACM Transactions on Internet Technology, 3(2):117-148, May 2003.

Michael Y. Levin and Benjamin C. Pierce. TinkerType: A Language for Playing with Formal Systems. Journal of Functional Programming, 13(2), March 2003. A preliminary version appeared as an invited paper at the Logical Frameworks and Metalanguages Workshop (LFM), June 2000.

Benjamin C. Pierce. Types and Programming Languages: The Next Generation, 2003. Invited tutorial at Logic in Computer Science (LICS).

Vladimir Gapeyev, Michael Levin, and Benjamin Pierce. Recursive Subtyping Revealed. Journal of Functional Programming, 12(6):511-548, 2003. Preliminary version in International Conference on Functional Programming (ICFP), 2000. Also appears as Chapter 21 of Types and Programming Languages by Benjamin C. Pierce (MIT Press, 2002).

Trevor Jim, Benjamin C. Pierce, and Jérôme Vouillon. How to Build a File Synchronizer. Manuscript, 2003.

Eijiro Sumii and Benjamin C. Pierce. Logical Relations for Encryption. Journal of Computer Security, 11(4):521-554, 2003. Extended abstract appeared in ph14th IEEE Computer Security Foundations Workshop, pp. 256-269, 2001.

Vladimir Gapeyev and Benjamin C. Pierce. Regular Object Types. In European Conference on Object-Oriented Programming (ECOOP), Darmstadt, Germany, 2003. A preliminary version was presented at FOOL '03.

M. Okada, B. Pierce, A. Scedrov, H. Tokuda, and A. Yonezawa, editors. Software Security - Theories and Systems, number 2609 in Lecture Notes in Computer Science. Springer-Verlag, 2003. Revised papers from the Mext-NSF-JSPS International Symposium on Software Security, Tokyo, Japan, November 8-10, 2002.

Benjamin C. Pierce and Alan Schmitt. Lenses and View Update Translation. Manuscript, 2003.

Michael B. Greenwald, Jonathan T. Moore, Benjamin C. Pierce, and Alan Schmitt. A Language for Bi-Directional Tree Transformations. Technical Report MS-CIS-03-08, University of Pennsylvania, 2003. Revised April 2004.

Benjamin C. Pierce, Alan Schmitt, and Michael B. Greenwald. Bringing Harmony to Optimism: A Synchronization Framework for Heterogeneous Tree-Structured Data. Technical Report MS-CIS-03-42, University of Pennsylvania, 2003. Superceded by MS-CIS-05-02.

Michael B. Greenwald, Jonathan T. Moore, Benjamin C. Pierce, and Alan Schmitt. A Language for Bi-Directional Tree Transformations. Manuscript; available at http://www.cis.upenn.edu/~bcpierce/papers/lenses.pdf, 2003.

Atsushi Igarashi and Benjamin C. Pierce. On Inner Classes. Information and Computation, 177(1):56-89, August 2002. A special issue with papers from the 7th International Workshop on Foundations of Object-Oriented Languages (FOOL), informal proceedings. An earlier version appeared in \bgroup Proceedings of the 14th European Conference on Object-Oriented Programming (ECOOP), Springer LNCS 1850, pages 129-153.

Benjamin C. Pierce. Synchronize globally, compute locally, July 2002. Keynote address at Research Day on Global Computing, EFPL, Lausanne.

Benjamin C. Pierce. Types and Programming Languages. MIT Press, 2002.


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Pedro Ponte-Castaneda

Professor of Mechanical Engineering and Applied Mechanics
Email: ponte at lrsm.upenn.edu
Personal Website

Research Interests:
Nonlinear Composite Materials: Most of the available theories for predicting the effective properties of composite materials assume linear constitutive behavior. However, more often than not, nonlinear effects are critical in the modeling of real engineering materials. This project addresses nonlinear constitutive and kinematical effects as observed in low-temperature plasticity and high-temperature creep of metal-matrix composites, as well as in the large-deformation behavior of black-filled elastomers.

Microstructure Evolution and Localization in Manufacturing Processes: Shear localization in metals plays an important role in restricting the potential applications of several manufacturing processes. This difficulty is compounded by the presence of microstructural defects that may enhance, or delay the onset of localizations during processing. This project is concerned with the theoretical development of constitutive models for porous materials, accounting for the evolution of the microstructure, which will be useful in assessing the effect of porosity on localization.

Low-Symmetry Polycrystals: A fundamental problem in materials engineering is the computation of the macroscopic behavior of polycrystalline aggregates from the microscopic behavior of their constituent grains and suitable microstructural information. Exactly 50 years since its introduction by G. I. Taylor, this is still being done by means of the uniform strain-rate approximation. While appropriate for high-symmetry crystals (e.g., FCC), the Taylor approach is highly inaccurate for low-symmetry crystals (e.g., HCP), especially when the number of independent slip systems is less than 5. In this project, the "second-order" procedure is used, fully accounting for crystallographic and morphological texture evolution.

Selected Recent Publications:
P. Ponte Castaneda. Linear comparison methods for nonlinear composites. In Nonlinear Homogenization and Applications to Composites, Polycrystals and Smart Materials (NATO Science Series), edited by B. Gambin, P. Ponte Castaneda and J. J. Telega, Kluwer. In press.

P. Ponte Castaneda and J. J. Telega (Eds.) Nonlinear Homogenization and Applications to Composites, Polycrystals and Smart Materials. NATO Science Series, Kluwer. In press.

Lopez-Pamies, O. Castaneda, P.P. Second-order estimates for the macroscopic response and loss of ellipticity in porous rubbers at large deformations. Source: Journal of Elasticity, v 76, n 3, Sept. 2004, p 247-87.

N. Aravas and P. Ponte Castaneda. Numerical methods for porous metals with deformation-induced anisotropy. Computer Methods in Applied Mechanics and Engineering, 2004: accepted.

P. Gilormini, Y. Liu and P. Ponte Castaneda. Application of a variational self-consistent procedure to the prediction of deformation textures in polycrystals. In Multi-Scale Modeling and Characterization of Elastic-Inelastic Behavior of Engineering Materials (IUTAM Symposium), edited by S. Ahzi et al., 17-24, New York: Kluwer, 2004.

R. Lebensohn, Y. Liu and P. Ponte Castaneda. Macroscopic properties and field fluctuations in model power-law polycrystals: full-field solutions versus second-order estimates. Proceedings of the Royal Society of London A 460, 2004: 1381-1405.

O. Lopez-Pamies and P. Ponte Castaneda. Second-order estimates for the effective behavior and field fluctuations in finite elasticity. Mathematics and Mechanics of Solids, 2004: in press.

O. Lopez-Pamies and P. Ponte Castaneda. Second-order estimates for the macroscopic response and loss of ellipticity in porous rubbers at large deformations. Journal of Elasticity, 76(3), September 204, p 247-287.

Y. Liu and P. Ponte Castaneda. Homogenization estimates for the average behavior and field fluctuations in cubic and hexagonal viscoplastic polycrystals. Journal of the Mechanics and Physics of Solids 52, 2004: 1175-1211.

Y. Liu and P. Ponte Castaneda. Second-order theory for the effective behavior and field fluctuations in viscoplastic polycrystals.Journal of the Mechanics and Physics of Solids 52 2004: 467-495.

P. Gilormini, Y. Liu and P. Ponte Castaneda. Homogenization-based predictions for texture evolution in halite. In Computational Mechanics of Solid Materials at Large Strains (IUTAM Symposium), edited by C. Miehe, 269-278, New York: Kluwer Academic Publishers, 2003.

P. Gilormini, Y. Liu and P. Ponte Castaneda. Variational self-consistent estimates for texture evolution in viscoplastic polycrystals-Application to titanium. Acta Materialia 51, 2003: 5245-5437.

M. Idiart and P. Ponte Castaneda. Field fluctuations and macroscopic properties for nonlinear composites. International Journal of Solids and Structures 40, 2003: 7015-7033.

O. Lopez-Pamies and P. Ponte Castaneda. Second-order estimates for the large deformation response of particle-reinforced rubbers. Comptes Rendus Mecanique 331, 2003: 1-8.

P. Ponte Castaneda. On the homogenized behavior of reinforced and other Bingham composites." Philosophical Transactions of the Royal Society of London A 361, 2003: 947-964.

J. P. Briggs and P. Ponte Castaneda. Variational estimates for the effective response of SMA-actuated fiber composites. Journal of Applied Mechanics 69, 2002: 470-480.

Y. Liu, P. Gilormini, and P. Ponte Castaneda. Application of the variational self-consistent model to the deformation textures of titanium. International Journal of Forming Processes 5, 2002: 327-336.

J. Pastor and P. Ponte Castaneda. Yield criteria for porous media in plane strain: second-order estimates versus numerical results. Comptes Rendus Mecanique 330. 2002: 741-747.

P. Ponte Castaneda. Second-order homogenization estimates for nonlinear composites incorporating field fluctuations. I. Theory. Journal of the Mechanics and Physics of Solids 50, 2002: 737-757.

P. Ponte Castaneda. Second-order homogenization estimates for nonlinear composites incorporating field fluctuations. II. Applications. Journal of the Mechanics and Physics of Solids 50, 2002: 759-782.


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David P. Pope

Professor of Materials Science and Engineering
Email: pope at seas.upenn.edu
Personal Website

Research Interests:
Brittle-to-ductile Transition: We have developed a model for this transition that is based on the homogeneous, cooperative nucleation of large numbers of dislocation loops, driven by high local stresses and aided by overlapping dislocation stress fields. We are testing the model by doing bending deformation experiments on high quality Si single crystals and finding that the behavior is qualitatively in agreement with the theory.

Deformation of Ordered Alloys, Laves Phases: This research concentrates on the deformation mechanisms of Laves phases (ordered alloys with a fairly complicated cubic or hexagonal crystal structure). Some of these alloys that deform by mechanical twinning and we have shown that the mechanism involves a non-homogeneous shear mechanism. The process appears to involve "sychroshear" which is a shear process in which two adjacent but very specific atomic planes undergo slip by ordinary Shockley partial dislocations.

Deformation of Ordered Alloys: Near-stoichiometric TiAl alloys with less than 52 atomic % Al form a lamellar microstructure with many layers of TiAl separated by (111) interfaces, with the occasional Ti3Al layer between. The deformation of this material is largely controlled by the (111) interfaces themselves. We are investigating how the interfacial planes control the deformation of this material and are finding that twinning and slip processes are very closely linked in this material, both spatially and temporally.

Selected Recent Publications:
Chen, Yali , Pope, David P., Vitek, Vaclav. Dislocation/Twin/Interface Interactions during Deformation of PST TiAl Single Crystals, an AFM Study. Materials Research Society Symposium - Proceedings, v 753, 2003, p 155-160.

Kim, Won-Yong, Luzzi, David E., Pope, David P. Room temperature deformation behavior of the Hf-V-Ta C15 Laves phase. Intermetallics, v 11, n 3, March, 2003, p 257-267.

Powell, R.M., Anderson, H., van der Spiegel, J., Pope, D.P. Using Web-based technology in laboratory instruction to reduce costs. Computer Applications in Engineering Education, v 10, n 4, Feb. 2003, p 204-14.

Kimura, Y., Luzzi, D.E., Pope, D.P. Deformation twinning in a HfV/sub 2/+Nb-based Laves phase alloy. Materials Science & Engineering A (Structural Materials: Properties, Microstructure and Processing), v A329-331, 2002, p 241-8.

Liu CT, Whang SH, Pope DP, et al. Special issue - 5th International Conference on Structural and Functional Intermetallics - 16-19 July, 2000, Vancouver, Canada - Preface. MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING 329: xiii-xiii Sp. Iss. SI JUN 2002.


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Sohrab Rabii

Professor of Electrical and Systems Engineering
Email: rabii at ee.upenn.edu
Personal Website

Research Interests:

High Pressure Phases of Alkali-Graphite Intercalation Compounds:
The structural parameters of new high pressure phases of lithium intercalated graphite are studied by total energy calculations using ab initio pseudopotentials, using local density functional formalism. The wavefunctions are used to obtain the momentum densities and directional Compton profile for the electrons in order to test the quality of the result by comparing them to measurements of inelstic scattering of photons from these compounds.

Electron Momentum Densities in Doped and Undoped Fullerines:Compton profiles are being calculated for C60, K3C60, and K4C60 using wavefunctions obtained from pseudopotential, local density functional calculations for this materials. The results are used to explain the discrepancies between the predictions of the LDA calclations and experimntal results.

Study of Equation of States for RbxC60 (x=3,4 and 6) . ab initio electronic structure calculations are carried out for these compounds as a fucntion of pressure and the resulting electon momentum densites are compared with directional Compton profiles measures as a function of tempreature and pressure.

Electronic Structure of MO2 (M = Co, Ni): These compounds have applications as electrodes in secondary batteries. We are calculating the electronci stuructue of these material using plavewave pseudopotential calculatiions within the local density functional approximation. The results are compared with measurements of inelastic phton scattering from these compounds.

Selected Recent Publications:

In Situ pressure study of Rb4C60 insulator to metal transition by Compton scattering. A.A.Sabouri-Dodaran, Ch.Bellin, M. Marangolo, G. Loupias, S, Rabii, F. Rachdi, Th. Buslaps, and M. Mezouar. Phys, Rev B 72, 086412(2005)

Equation of state of RbxC60 (x=3,4 and 6). A. Sabouri-Dodaran, M. Marangolo, Ch. Belin, F. Mauri, G. Fiquet, G. Loupias. M. Mezouar, W. Chrichton, F. Rachdi, C. Hérold and S. Rabii. Phy. Rev. B 70, 174117(2004)

Electronic density distortion of NiO2 due to intercalation by Li S. Chabaud, Ch. Bellin, F. Mauri, G. Loupias, S. Rabii, L. Croguennee, C.Pouillerie, C. Delmas, and Th. Buslap. J. Phys. and Chem. of Solids 65, 241-243(2004)

Evidence of a weak electronic density distortion in polymerized A 1C 60 (A=K and Rb) compared to pristine C 60. M. Marangolo, Ch. Bellin, G. Loupias, S. Rabii, S.C. Erwin, Th. Bislaps and A. Issolah Physica B, 318, 365 (2002)

Momentum density of electrons in CsRb2C60, versus Temperature
M. Marangolo, G. Loupias, S. Rabii, S. Erwin, C. Herold, J-F. Marêché, Ph. Lagrange, T. Buslap, P. Suortti. J. of Molecular and Liquid Crystals, 339, 217(2000).

Experimental and theoretical study of electron momentum density of AnC60 (n=3,4) and comparison with pristine C60. M. Marangolo, Ch. Bellin, G. Loupias, , S. Rabii, S. C. Erwin, Th. Buslap. Phys. Rev. B 60, 17084 (1999).

Experimental and theoritical study of electron density of K6C60 and comparison to pristine C60. M. Marangolo, J. Moscovici, G. Loupias, , S. Rabii, S. C. Erwin, C. Hérold, J-F. Marêché and Ph. Lagrange. Phys. Rev. B 58, 7593 (1998).

Selected recent conference presenrations

Study of insulator to metal transition in Rb4C60 by coheent and incoherent X-ray scattering under pressure. A.A. Sabouri-Dodaran, Ch. Bellin, M. Marangolo, F. Mauri, G. Fiquet, G. Loupias, M. Mezouar, Th. Buslap, F. Rachdi, C. Herold and S. Rabii. 13th International Symposium on Intercalation Compounds, June 6-9, Clermont-Ferrand, France

Equation of state of Rb4C60. A.A. Sabouri-Dodaran, M. Marangolo, Ch. Bellin, F. Mauri, G. Fiquet, G. Loupias, M. Mezouar, W. Crichton, Th. Buslap, F. Rachdi, C. Herold and S. Rabii. 13th International Symposium on Intercalation Compounds, June 6-9, Clermont-Ferrand, France

Study of Metal-insulator transition in Rb4C60 by Compton scattering, under pressure. Genevieve Loupias, A. A. Sabouri-Dodaran, M. Marangolo, Ch. Bellin, F. Mauri, S. Rabii, Th. Buslaps, M. Mezouar and W. Crichton. Sagamore XIV Conference on Charge, Momentum and Spin Densities, August 13-18, 2003, Broome, North West Territory, Australia.

Electronic distortion of the host density in LixMO2 (M = Co, Ni) by Compton Scattering. Invited Paper: 12th International Symposium on Intercalation Compounds, June 1-5, 2003, Poznan, Poland.

Study of metal-insulator transition in Rb4C60 by Compton scattering, under pressure. A. A. Sabouri Dodaran, Ch. Bellin, M. Marangolo, F. Mauri, G. Loupias, S. Rabii, Th. Buslaps, M. Mezouar and W. Crichton
International Conference on Numerical Methods in Electronic Structure Theory, ICTP, Trieste, Italy, 1/16/2003.

Study of metal-insulator transition in Rb4C60 by Compton scattering under pressure. M Marangolo, A. Sabouri, Ch. Bellin, F. Mauri, G. Loupias, S. Erwin, S. Rabii, F. Rachdi, Th. Buslaps, M. Mezouar,
XI Int. Symposium on Intercalation Compounds,.Moscow, Russia, 26-31 May 2001

Electron density distortion of LixMO2 (M= Co, Ni) as a function of x
S, Chabaud, F.Mauri, C. Bellin, G.Loupias, S. Rabii, L. Crogueennec, C. Pouillerie and C.Delmas. XI Int. Symposium on Intercalation Compounds,.Moscow, Russia, 26-31 May 2001

Experimental and theoretical study of electron momentum density of AnC60 (n=3,4 and 6, A= alkali ions) and comparison to pristine C60
M.Marangolo, G.Loupias, S.Rabii, S.C.Erwin,and T. Buslaps
Sagamore XIII, Conf. on Charge, Spin and Momentum Densities, Stare Jablonki, Poland, 3-9 Sept. 2000

Compton and XANES studies of LixMO2 (M= Co, Ni). S.Chabaud, F.Mauri, C. Bellin, G.Loupias, S. Rabii, L. Crogueennec, C. Pouillerie and C.Delmas. Sagamore XIII, Conf. on Charge, Spin and Momentum Densities, Stare Jablonki, Poland, 3-9 Sept. 2000


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Ravi Radhakrishnan

Assistant Professor of Bioengineering
Email: rradhak at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Studying biochemical phenomena at various length and timescales from electronic structure to signaling pathways by employing tools from Computational Biology, Statistical Mechanics, and Quantum Mechanics. Dr. Radhakrishnan's research lies in the interface of chemical physics and molecular biology and is currently focused on various biophysical and biochemical problems spanning carcinogenesis, therapeutic inhibition of signaling enzymes, RNA catalysis, membrane phenomena, and targeted drug delivery.

Selected Recent Publications:

R. Radhakrishnan, T. Schlick, Fidelity Discrimination in DNA polymerase beta: differing closing profiles for a mismatched (G:A) versus matched (G:C) base pair, J. Am. Chem. Soc., 2005, in press.

C.S. Lo, R. Radhakrishnan, and B.L. Trout. Application of transition path sampling methods in catalysis: A new mechanism for C-C bond formation in the methanol coupling reaction in chabazite. Catalysis Today, 2005, 105, 93-105.

R. Radhakrishnan and T. Schlick, "Biomolecular Free Energy Profiles by a Shooting/Umbrella Sampling Protocol (BOLAS)", 2004, J. Chem. Phys., 121, 2436.

R. Radhakrishnan and T. Schlick, "Orchestration of cooperative events in DNA synthesis and repair mechanism unraveled by transition path sampling of DNA polymerase beta’s closing", 2004, Proc. Nat. Acad. Sci., 101, 5970.

R. Radhakrishnan, B. L. Trout, "Nucleation of crystalline phases of water under homogeneous and inhomogeneous environments", 2003, Phys. Rev. Lett., 90, 158301

C. Lo, C. A. Giurumescu, R. Radhakrishnan, B. L. Trout, "Methanol coupling in the zeolite chabazite studied via first-principles molecular dynamics", 2004 Mol. Phys., 102, 281

R. Radhakrishnan and T. Schlick. Transition path sampling of DNA polymerase's closing conformational change unravels orchestration of cooperative events in DNA synthesis and repair mechanisms. Proc. Nat. Acad. Sci., in press, 2004.

R. Radhakrishnan, B. L. Trout. Order parameters in molecular simulations. Handbook of Materials Modeling, Ed. S. Yip, Chapter 6, Kluwer Academic Publishers, Dordrecht, in press. (invited paper)

K. E. Gubbins, M. Sliwinska-Bartkowiak, R. Radhakrishnan. Effect of confinement on freezing and melting. To be submitted to J. Phys.: Cond. Matter, 2003.

C. Lo, C. A. Giurumescu, R. Radhakrishnan, B. L. Trout. Methanol coupling in the zeolite chabazite studied via first-principles molecular dynamics. Mol. Phys., in press, 2003

R. Radhakrishnan, A. Demurov, H. Herzog, B. L. Trout. A consistent and verifiable model for the dissolution of CO2 in water under hydrate forming conditions. Energy Conversion Management, 44, 771, 2003.

R. Radhakrishnan and T. Schlick. Biomolecular Free Energy Profiles by a Shooting/Umbrella Sampling Protocol (BOLAS). Submitted to J. Chem. Phys, 2003.

R. Radhakrishnan, B. L. Trout. Nucleation of crystalline phases of water under homogeneous and inhomogeneous environments. Phys. Rev. Lett., 90, 158301, 2003.

R. Radhakrishnan, B. L. Trout. Nucleation of hexagonal ice Ih in liquid water. J. Am. Chem. Soc., 125, 7743, 2003.

A. Demurov, R. Radhakrishnan, and B. L. Trout. Computations of Diffusivities in ice and CO2 clathrate via molecular dynamics and Monte Carlo simulations. J. Chem. Phys., 116(2) 702, 2002.

R. Radhakrishnan, M. Sliwinska-Bartkowiak, and K. E. Gubbins. Global Phase Diagrams for Freezing in Porous Media. J. Chem. Phys., 116(3), 1147, 2002.

R. Radhakrishnan, M. Sliwinska-Bartkowiak, and K. E. Gubbins. The nature of Kosterlitz-Thouless transition in quasi-two-dimensional fluids confined in porous media. To be submitted to J. Chem. Phys, 2002.

R. Radhakrishnan, B. L. Trout. A new approach for studying nucleation phenomena using molecular simulations: Application to CO2 hydrate clathrates. J. Chem. Phys., 117(4), 1786, 2002.


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Amir Roth

Assistant Professor of Computer and Information Science
Email: amir at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Computer architecture, microprocessor and memory system design, performance evaluation, novel computing models and platforms, and the interaction of computer architecture, compilation techniques and systems software. Among my currently active projects are pre-execution and p-thread selection, register integration, and dynamic instruction stream editing (dise) which is a collaboration with professor E Lewis.

Selected Recent Publications:
Corliss, M.L.; Lewis, E.C.; Roth, A. Using DISE to protect return addresses from attack. Computer Architecture News, v 33, n 1, March 2005, p 65-72.

Amir Roth. Store Vulnerability Window (SVW): Re-Execution Filtering for Enhanced Load Optimization. In Proc. of ISCA-32, June 6-8 2005.

Vlad Petric and Amir Roth. Energy Aspects of Pre-Execution and Energy-Aware- P-Thread Selection. In Proc. of ISCA-32, June 6-8 2005.

Vlad Petric, Tingting Sha, and Amir Roth. RENO: A Rename-Based Instruction Optimizer. In Proc of. ISCA-32, June 6-8 2005.

Marc L. Corliss, E. Christopher Lewis, and Amir Roth. Low-Overhead Interactive Debugging Using DISE. In Proc. of HPCA-11, February 12-16 2005.

Anne Bracy, Prashant Prahlad, and Amir Roth. Dataflow Mini-Grpahs: Amplifying Superscalar Capacity and Bandwith. Micro-37, December 2004.

Marc L. Corliss, E Christopher Lewis and Amir Roth. A DISE Implementation of Dynamic Code Decompression. In proc. of LCTES-03, Jun. 11-13, 2003.

Marc L. Corliss, E Christopher Lewis and Amir Roth. DISE: A Programmable Macro Engine for Customizing Applications In proc. of ISCA-30, Jun. 9-11, 2003..

Vlad Petric, Anne Bracy, and Amir Roth. Three Extensions to Register Integration. In proc. of MICRO-35, Nov. 20-22, 2002.

Amir Roth and Gurindar S. Sohi. A Quantitative Framework for Automated Pre-Execution Thread Selection. In proc. of MICRO-35, Nov. 20-22, 2002.

Amir Roth and Gurindar S. Sohi. Squash Reuse via a Simplified Implementation of Register Integration. Journal of Instruction Level Parallelism (JILP), Vol. 3, 2002.

Marc L. Corliss, E Christopher Lewis and Amir Roth. DISE: Dynamic Instruction Stream Editing. CIS Technical Report MS-CIS-02-24, Jul. 2002.

Amir Roth, Anne Bracy, and Vlad Petric. Three Extensions to Register Integration. CIS Technical Report MS-CIS-02-22, Jul. 2002.

Amir Roth and Gurindar S. Sohi. A Quantitative Framework for Pre-Execution Thread Selection. CIS Technical Report MS-CIS-02-23, Jul. 2002.


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Jorge J. Santiago-Aviles

Associate Professor of Electrical and Systems Engineering
Email: santiago at ee.upenn.edu
Personal Website

Research Interests:
Meso-scale Electro-Mechanical Systems and Sensors: Often the minute size associated with MEMS (micro-electromechanical systems) is traded off for low cost or the ability of the system or device to operate in harsh environment such as temperature of several hundred degrees Celsius or very corrosive or reacting gases or liquids. With this thought in mind we are involved in the design, fabrication and interfacing of ceramic and plastic based meso-scale (from 10 micrometers to several centimeters) electro-mechanical systems such as high temperature pressure transducers, flow meters, electro-magnetically actuated valves, electrophoretic channels, micro-fluidic devices and others. The basic materials science and manufacturing issues encountered during design and fabrication are pursued utilizing theoretical, numerical and experimental tools.

Selected Recent Publications:
E. W. Simoes, Furlan, R., L. Bruzetti, et al. Microfluidic oscillator for gas flow control and measurement. Flow Measurement and Instrumentation, v 16, n 1, March 2005, p 7-12.

Y. Wang, M. Aponte, N. Leon, et al. Synthesis and characterization of tin oxide microfibres electrospun from a simple precursor solution. Semiconductor Science and Technology, v 19, n 8, August 2004, p 1-57-1060.

Y. Wang, R.Furlan, I . Ramos and J.J. Santiago-Avilés. Electronic Transport Properties of Incipient Graphite Domains Formation in PAN-Derived Carbon Nano-Fibers. IEEE Transactions in Nanotechnology. 3(1), 80, 2004.

Y. Wang, J.J. Santiago-Aviles. Synthesis of lead zirconate titanate nanofibres and the Fourier-transform infrared characterization of their metallo-organic decomposition process. Nanotechnology, v 15, n 1, January 2004, p 32-36.

Y.Wang, R. Furlan, I. Ramos, and J.J. Santiago-Avilés. Synthesis and Characterization of Micro/Nanoscopic PZT Fibers by Electrospinning. Applied Physics A, 78, 1043, 2004.

Y. Wang, and J.J. Santiago-Avilés. Low Temperature Electronic Properties of Electrospun PAN-Derived Carbon Nanofibers. IEEE Transactions in Nanotechnology 3(2), 221, 2004.

N. Beltran, V. Fuenzalida and J.J.Santiago-Aviles. Effect of parasitic capacitances on impedance measurements in microsensors structures: A numerical study. Sensors and Actuator (B), 96/1-2, 139, 2003.

Y. Wang and J.J. Santiago-Aviles. Large Negative Magnetoresistance and 2D Weak Localization In Carbon Nanofibers Fabricated Using Electrospinning. Journal of Applied Physics, 94(3) 1721, 2003.

Y. Wang and J.J. Santiago-Avilés. Magnetoconductance, Carrier Concentration and Mobility Measurements on Electrospun Carbon Fibers. Carbon, 41(12), 2665, 2003.

Y. Wang and J. J. Santiago-Avilés. Synthesis of PZT Nanofibers and the FTIR Characterization of Its MOD Process. Nanotechnology, 15-1, 32 - 36, 2003.

Y.Wang, J.J. Santiago-Aviles, R.Furlan and I. Ramos. Pyrolysis Temperature and Time Dependence of Electrical Conductivity Evolution or Electrostatically Generated Carbon Nano-Fibers. IEEE Transactions in Nanoelectronics, 2(1),1, 2003.

Y.Wang, S. Serrano and J. J. Santiago-Aviles. Conductivity Measurement of Electrospun PAN-based Carbon Nanofiber. Journal of Materials Science Letters 24,1055, 2002.

Y.Wang, S. Serrano and J. J. Santiago-Aviles. Raman Characterization of Graphitization of Electrostatically Prepared Carbon Nanofibers. Synthetic Metals 9567, 1-5, 2002.


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Saswati Sarkar

Assistant Professor of Electrical and Systems Engineering
Email: swati at ee.upenn.edu
Personal Website

Research Interests:
My research interests are in the general area of communications networks withemphasis on resource allocation, routing and scheduling, optimization and control of stochastic systemss, distributed systems and algorithms, quality of service and pricing issues. A brief description of my research areas follow.Resource allocation in multicast networks: The bulk of the multicast traffic in internet consists of multimedia applications, which consume huge network resources. Good resource allocation strategies can be used for congestion control. The constraint is that any practical resource allocation strategy must be comutationally simple, adaptive and local information based. We have investigated routing and scheduling policies which optimize the system performance and satisfies the above constraints. Multicast transmission allows several receivers to join the same applicaton. These receivers have diverse requirements and capabilities. For this purpose, the multimedia signals are coded in several levels of precisions, and receivers adapt to congeston by appropriately choosing the precision level of reception. This advanced multimedia coding technique calls for innovative distribution strategies. We have studied network resource allocation for multilevel coding, and have developed computing and scheduling strategies for ataining several resource allocation objectives. Resource allocation in wireless networks: Bandwidth is a scarce commodiy in wireless networks. The transmission conditions are normally far from perfect, and induce channel errors. A major reason of poor transmission conditions is the interference from other users using the same transmission bandwidth. So resource allocation srategies need to respond to time varying channel conditions and congestion related losses. Quality of service requirements often impose restrictions on allowable interference level. We have studied bandwidth allocation and channel reuse strategies in mobile cellular networks under cochannel and adjacent channel interference constraints. We have investigated the modelling of these interference constrants with the objective of efficient resource allocation, and have developed fixed channel allocaion strategies for attainng several fairness objectives.

Selected Recent Publications:

Saswati Sarkar, Leandros Tassiulas, "End-to-end Bandwidth Guarantees Through Fair Local Spectrum Share in Wireless Adhoc Networks'' Accepted for publication in IEEE Transaction on Automatic Control

Saswati Sarkar, Leandros Tassiulas, "Back pressure based multicast scheduling for fair bandwidth allocation'' Accepted for publication in IEEE Transaction on Neural Networks: Special Issue on Adaptive Learning Systems in Communication Networks.

Prasanna Chaporkar, Saswati Sarkar, "Wireless Multicast: Theory and Approaches'' IEEE Transaction on Information Theory, Vol. 51, No. 6, pp. 1954 - 1972, June 2005.

Saswati Sarkar, Farooq Anjum, Ratul Guha, "Optimal Communication in Bluetooth Piconets,'' IEEE Transaction of Vehicular Technology, Vol. 54, No. 2, pp. 709-721, March, 2005.

Evangelos Vergetis, Roch Guerin, Saswati Sarkar, Jacob Rank, "Can Bluetooth Succeed as a Large-Scale Ad Hoc Networking Technology?'' IEEE Journal for Selected Areas in Communications, Special Issue on Ad Hoc Networks, Part II, Vol. 23, No. 3, pp. 644-656, March 2005.

Saswati Sarkar, Leandros Tassiulas, "Fair Distributed Congestion Control for Multirate Multicast Networks,'' IEEE/ACM Transaction in Networks, vol. 13, no. 1, pp. 121-133, February 2005.

Leandros Tassiulas, Saswati Sarkar, "Maxmin fair scheduling in wireless Ad hoc Networks,'' IEEE Journal for Selected Areas in Communications Special Issue on Ad Hoc Networks, Part I, Vol. 23, No. 1, January 2005, pp. 163-173.

Saswati Sarkar, "Optimum Scheduling and Memory Management in Input Queued Switches with Finite Buffer Space,'' IEEE Transaction of Information Theory, Vol. 50, No. 12, December 2004, pp. 3197-3220.

Koushik Kar, Saswati Sarkar, Leandros Tassiulas, "Achieving Proportional Fairness Using Local Information in Aloha Networks,'' IEEE Transactions of Automatic Control, Vol. 49, No. 10, October 2004, pp. 1858-1862.

Dhanant Subhadrabandhu, Saswati Sarkar, and Faroog Anjum. Efficacy of misuse detection in adhoc neteworks. IEEE Communications Society Conference on Sensor and Ad Hoc Communications and Networks, 2004, p 97-107.

Faroog Anjum, Dhanant Subhadrabandhu, Saswati Sarkar, and Rahul Shetty On optimal placement of intrustion detection modules in sensor networks. First International Conference on Broadband Networks, BroadNets 2004, p 690-699.

Ratul K. Guha, Carl A. Gunter, and Saswati Sarkar. Fair coalitions for power-aware routing in wireless networks. IEEE Confernce on Decision and Control, p 3271-3276.

Saswati Sarkar, Leandros Tassiulas. Fair Bandwidth Allocation for Multicasting in Networks with Discrete Feasible Set. EEE Transaction of Computers, July 2004, Vol. 53, No. 7, pp. 785-797.

Prasanna Chaporkar, Saswati Sarkar. An Adaptive Strategy for Maximizing Throughput in MAC layer Wireless Multicast. To appear in Proceedings of MOBIHOC 2004, Tokyo, Japan, May 24-26, 2004.

Prasanna Chaporkar, Saswati Sarkar. On-line Optimal Wireless Multicast. Proceedings of the 2nd Workshop On Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks. Cambridge, England, pp. 282-291, March 24-26, 2004

Prasanna Chaporkar, Saswati Sarkar. Stochastic Control Techniques for Throughput Optimal Wireless Multicast. Proceedings of Control and Decision Conference (CDC), 2003, Maui, Hawaii, December 9-12, 2003

Saswati Sarkar, Leandros Tassiulas. End-to-end bandwidth guarantees through fair local spectrum share in wireless ad-hoc networks. Proceedings of Control and Decision Conference (CDC), 2003, Maui, Hawaii, December 9-12, 2003

Farooq Anjum, Dhanant Subhadrabandhu, Saswati Sarkar. Intrusion Detection for Wireless Adhoc Networks. Proceedings of Vehicular Technology Conference, Wireless Security Symposium, Orlando, Florida, October 2003.

Koushik Kar, Saswati Sarkar, Leandros Tassiulas. Achieving Proportional Fairness using Local Information in Multihop Aloha Networks.Proceedings of 41st Annual Allerton Conference on Communication, Control and Computing, Allerton, Monticello, Illinois, October 1-3, 2003.

Prasanna Chaporkar, Saswati Sarkar. Admission Control Framework to Provide Guaranteed Delay in Error-prone Wireless Channel. Proceedings of Vehicular Technology Conference, Wireless QoS Symposium, Orlando, Florida, October 2003.

Prasanna Chaporkar, Saswati Sarkar. A Dynamic Threshold Selection Policy for Retransmission in MAC Layer Multicast. Proceedings of 41st Annual Allerton Conference on Communication, Control and Computing, Allerton, Monticello, Illinois, October 1-3, 2003.


Roch Guerin, Jacob Rank, Saswati Sarkar, Evangelos Vergetis. Forming Connected Topologies in Bluetooth Adhoc Networks. Proceedings of International Teletraffic Congress (ITC18), Berlin, Germany, September 2003, pp. 1011-1020.

Sanjeev Khanna, Saswati Sarkar, Insik Shin. An Energy Management Based Collision Resolution Protocol. Proceedings of International Teletraffic Congress (ITC18), Berlin, Germany, September 2003, pp. 951-960 Technical Report.

Saswati Sarkar, Farooq Anjum, Ravi Jain. Throughput Optimal Packet Size Selection (TOPS) for Bluetooth Networks. pp. 151-160 Proceedings of International Teletraffic Congress (ITC18), Berlin, Germany, September 2003, Technical Report.

Prasanna Chaporkar , Saswati Sarkar. MAC layer wireless multicast: Theory and Approach. Proceedings of International Symposium on Information Theory, ISIT 2003, pp. 397, Yokohama, Japan June 29- July 4, 2003.

Saswati Sarkar. Optimum Scheduling and Memory Management in Input Queued Switches with Finite Buffer Space. Proceedings of IEEE INFOCOM, 2003, San Francisco, April 2003.

Saswati Sarkar, Maria Adamou. A Framework for Optimal Battery Management for Wireless Nodes. IEEE Journal for Selected Areas in Communication, special issue on wireless LANs and Home Networks, February 2003, Vol. 21, No. 2, pp. 179-188

Maria Adamou, Saswati Sarkar. Computationally Simple Battery Management Techniques for Wireless Nodes. Invited Paper, European Wireless, Florence 2002, pp. 218-223.

Maria Adamou, Saswati Sarkar. A Framework for Optimal Battery Management for Wireless Nodes. Proceedings of INFOCOM 2002, pp. 1783-1792.

Roch Guerin, Eunyoung Kim, Saswati Sarkar. Bluetooth Technology: Key Challenges and Initial Research. Invited Paper, Conference on Network and Distributed Simulations, 2002.

Saswati Sarkar. A Jointly Optimum Scheduling and Memory Management for Matching Based Service. Proceedings of IEEE CDC, 2002, Las Vegas, December 2002, pp. 2371-2376

Koushik Kar, Saswati Sarkar, Leandros Tassiulas. A scalable low overhead rate control algorithm for multirate multicast sessions. IEEE Journal of Selected areas in Communication, Special issue in Network Support for Multicast Communications, October 2002, Vol. 20, No. 8, pp. 1541-1557

Saswati Sarkar, Leandros Tassiulas. A Framework for Routing and Congestion Control for Multicast Information Flows. IEEE Transactions on Information Theory, October 2002, Vol. 48, No. 10, pp. 2690-2708.

Prasanna Chaporkar , Saswati Sarkar. Providing Stochastic Delay Guarantees Through Channel Characteristics Based Resource Reservation in Wireless Network. Proceedings of Wireless Workshop on Mobile Multimedia, WoWMoM 2002, Atlanta, September 2002, pp. 1-8.

Saswati Sarkar, Tianmin Ren, Leandros Tassiulas. Achieving Fairness in Multicasting with Almost Stateless Rate Control. Invited Paper Proceedings of SPIE, (Scalability and Traffic Control In IP Networks, II) Vol. 4868, pp. 16-30, ITCOM 2002, Boston.

Saswati Sarkar, Kumar N. Sivarajan. Channel Assignment Algorithms Satisfying Cochannel and Adjacent Channel Reuse Constraints in Cellular Mobile Networks. IEEE Transactions on Vehicular Technology,Vol. 51, No. 5, pp.954-967, September, 2002.

Saswati Sarkar, Kumar N. Si varajan. Fairness in Wireless Mobile Networks. IEEE Transactions of Information Theory, Vol. 48, No. 8, pp. 2412-2426, Aug. 2002.

Saswati Sarkar, Leandros Tassiulas. Fair Allocation of Utilities in Multirate, Multicast Networks: A framework for unifying diverse fairness objectives. IEEE Transactions of Automatic Control, Special Issue on Control problem in communication networks, Vol. 47, No. 6, June 2002, 931-944

Saswati Sarkar, Leandros Tassiulas End-to-end bandwidth guarantees through fair local spectrum share in wireless ad-hoc networks. 2002.

Leandros Tassiulas, Saswati Sarkar. Maxmin Fair Scheduling in Wireless Networks. Proceedings of INFOCOM 2002, pp. 763-772.


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Lawrence Saul

Associate Professor of Computer and Information Science
Email: lsaul at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
Neural computation and statistical learning

Selected Recent Publications:

K. Q. Weinberger, B. D. Packer, and L. K. Saul (2005). Nonlinear dimensionality reduction by semidefinite programming and kernel matrix factorization. To appear in Z. Ghahramani and R. Cowell (eds.), Proceedings of the Tenth International Workshop on Artificial Intelligence and Statistics, Barbados, West Indies. Best student paper award.

J. H. Ham, D. D. Lee, and L. K. Saul (2005). Semisupervised alignment of manifolds. To appear in Z. Ghahramani and R. Cowell (eds.), Proceedings of the Tenth International Workshop on Artificial Intelligence and Statistics, Barbados, West Indies.

F. Sha and L. K. Saul (2005). Real-time pitch determination of one or more voices by nonnegative matrix factorization. To appear in L. K. Saul,
Y. Weiss, and L. Bottou (eds.), Advances in Neural Information Processing Systems 17. MIT Press: Cambridge, MA.

J. Blitzer, K. Q. Weinberger, L. K. Saul, and F. C. N. Pereira (2005). Hierarchical distributed representations for statistical language models. To appear in L. K. Saul, Y. Weiss, and L. Bottou (eds.), Advances in Neural Information Processing Systems 17. MIT Press: Cambridge, MA.

L. K. Saul, Y. Weiss, and L. Bottou (eds.) (2005). Advances in Neural Information Processing Systems 17: Proceedings of the 2004 Conference, MIT Press: Cambridge, MA.

Y. Mao and L. K. Saul (2004). Modeling distances in large-scale networks by matrix factorization. In Proceedings of the Second Internet Measurement Conference (IMC-04), pages 278-287. Sicily, Italy.

K. Q. Weinberger, F. Sha, and L. K. Saul (2004). Learning a kernel matrix for nonlinear dimensionality reduction. In Proceedings of the Twenty First International Confernence on Machine Learning (ICML-04), pages 839-846. Banff, Canada. Outstanding student paper award.

K. Q. Weinberger and L. K. Saul (2004). Unsupervised learning of image manifolds by semidefinite programming. In Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR-04), vol. 2, pages 988-995. Washington D.C. Outstanding student paper award.

V. Jain and L. K. Saul (2004). Exploratory analysis and visualization of speech and music by locally linear embedding. Proceedings of the International Conference of Speech, Acoustics, and Signal Processing (ICASSP-2004), Montreal, Canada.

Y. Lin, D. D. Lee, and L. K. Saul (2004). Nonnegative deconvolution for time of arrival estimation. Proceedings of the International Conference of Speech, Acoustics, and Signal Processing (ICASSP-2004), Montreal, Canada.

F. Sha, J. A. Burgoyne, and L. K. Saul (2004). Multiband statistical learning for f0 estimation in speech. Proceedings of the International Conference of Speech, Acoustics, and Signal Processing (ICASSP-2004), Montreal, Canada.

S. Thrun, L. K. Saul, and B. Schoelkopf (eds.) (2004). Advances in Neural Information Processing Systems 16, MIT Press: Cambridge, MA.

K. Q. Weinberger, F. Sha, and L. K. Saul (2004). Learning a kernel matrix for nonlinear dimensionality reduction. Proceedings of the Twenty First International Confernence on Machine Learning (ICML-04), Banff, Canada.

K. Q. Weinberger and L. K. Saul (2004). Unsupervised learning of image manifolds by semidefinite programming. Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR-04), Washington D.C.

J. H. Ham, D. D. Lee, and L. K. Saul (2003). Learning high dimensional correspondences from low dimensional manifolds. In Proceedings of the ICML 2003 Workshop on The Continuum from Labeled to Unlabeled Data in Machine Learning and Data Mining, pages 34-41, Washington, D.C.

F. Sha, L. K. Saul, and D. D. Lee (2003). Multiplicative updates for large margin classifiers. In Proceedings of the Sixteenth Annual Conference on Computational Learning Theory, pages 188-202, Washington D.C.

L. K. Saul, D. D. Lee, C. L. Isbell, and Y. LeCun (2003). Real time voice processing with audiovisual feedback: toward autonomous agents with perfect pitch. In S. Becker, S. Thrun, and K. Obermayer (eds.), Advances in Neural Information Processing Systems 15, pages 1205-1212. MIT Press: Cambridge, MA.

L. K. Saul and S. T. Roweis (2003). Think globally, fit locally: unsupervised learning of low dimensional manifolds. Journal of Machine Learning Research 4:119-155.

L. K. Saul, F. Sha, and D. D. Lee (2003). Statistical signal processing with nonnegativity constraints. In Proceedings of the Eighth European Conference on Speech Communication and Technology, volume 2, pages 1001-1004, Geneva, Switzerland.

A. I. Schein, L. K. Saul, and L. Ungar (2003). A generalized linear model for principal component analysis of binary data. In C. M. Bishop and B. J. Frey (eds.), Proceedings of the Ninth International Workshop on Artificial Intelligence and Statistics, pages 14-21, Key West, FL.

F. Sha, L. K. Saul, and D. D. Lee (2003). Multiplicative updates for nonnegative quadratic programming in support vector machines. In S. Becker, S. Thrun, and K. Obermayer (eds.), Advances in Neural Information Processing Systems 15, pages 1065-1073. MIT Press: Cambridge, MA.

S. T. Roweis, L. K. Saul and G. E. Hinton (2002). Global coordination of locally linear models. In T. G. Dietterich, S. Becker, and Z. Ghahramani (eds.), Advances in Neural Information Processing Systems 14, pages 889-896. MIT Press: Cambridge, MA.

L. K. Saul and D. D. Lee (2002). Multiplicative updates for classification by mixture models. In T. G. Dietterich, S. Becker, and Z. Ghahramani (eds.), Advances in Neural Information Processing Systems 14, pages 897-904. MIT Press: Cambridge, MA.


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Peter W. Scherer

Professor of Bioengineering; Member of the Monell Institute of the Chemical Senses
Email: scherer at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Our main research thrust is in using computer numerical modeling to simulate human nasal airflow and odorant uptake on the nasal mucosal walls. We do this in conjunction with olfactory measurements on human subjects carried out at the Monell Institue of Taste and Smell. We are also developing a method of noninvasive cardiac output recovery based on comparing the predictions of a numerical model on lung CO2 washout from the mouth with actual patient measurements. A third research area is the development of a numerical clinical tool in which surgical changes in human nasal cavity anatomy (mostly to relieve nasal obstruction) are modeled before surgery on a computer to optimize the surgical effect on nasal air flow.

Selected Recent Publications:
P.W. Scherer and K. Zhao. Anatomical and Physiological Basis Of Volume Capnography Studied By The Single Path Model, book chpt (32) in book: Capnography - clinical Aspects, Eds. Gravenstein, Jaffe, Paulus, Cambridge U. Press, 2004.

D. Kurtz, K. Zhao, D. Hornung, and P. Scherer. Experimental and Numerical Determination of Odorant Solubility in Nasal and Olfactory Mucosa. Chemical senses, V. 29, no. 9 Oxford U. Press, p. 763-773, 2004.

Zhao, Kai, P.W.Scherer, S.A. Hajiloo, and P. Dalton. Effect of Anatomy on Human Nasal Air Flow and Odorant Patterns: Implications for Olfaction. Chem Senses 29: 365-379, 2004.


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John C. Schotland

Associate Professor of Bioengineering
Email: schotland at seas.upenn.edu
Personal Website

Research Interests: Dr. Schotland's research is focused on theoretical optical physics with applications to biomedical imaging and nano-optics. Areas of current interest include optical tomography, optical imaging of nanoscale systems, and the use of quantum states of light for optical imaging. Inverse problems, particularly inverse scattering problems, are a unifying theme which connects these areas.

Selected Recent Publications:
Markel, V.A. and Schotland, J.C. Multiple projection optical diffusion tomography with plane wave illumination. Physics in Medicine and Biology, v 50, n 10, May 21 2005, p 2351-2364.

Markel, V. and Schotland, J. Symmetries, Inversion Formulas, and Image Reconstruction for Optical Tomography. Phys. Rev. E 70, 056616 (2004).

Carney, S., Schotland, J. and Wolf, E. A Generalized Optical Theorem for Reflection, Transmission and Extinction of Optical Power. Phys. Rev. E, 70, 036611 (2004).

Markel, V. and Schotland, J. Dual-Projection Optical Tomography. Opt. Lett. 17, 2019-2022 (2004).

Carney, S., Frazin, R., Bozhevolnyi, S., Volkov, V., Boltasseva, A., and Schotland, J. Computational Lens for the Near-Field. Phys. Rev. Lett. 92, 163903-1--163903-4, 2004.

Carney, S. and Schotland, J. Near-Field Tomography. in Inside-Out: Inverse Problems and Applications, Cambridge University Press, 2003.

Carney, S. and Schotland, J. Theory of Total Internal Reflection Tomography. J. Opt. Soc. Am. 20, 542, 2003.

Markel, V., Mital, V. and Schotland, J. Inverse Problem in Optical Diffusion Tomography. III Inversion Formulas and Singular Value Decomposition. J. Opt. Soc. Am. A 20, 890, 2003.

Markel, V., O'Sullivan, J. and Schotland, J. Inverse Problem in Optical Diffusion Tomography. IV Nonlinear Inversion Formulas. J. Opt. Soc. Am. A 20, 903, 2003.

Carney, S. and Schotland, J. Determination of Three-Dimensional Structure in Photon Scanning Tunneling Microscopy. J. Opt. A 4, S140-S144, 2002.

Markel, V. and Schotland, J. Effects of Sampling and Limited Data in Optical Tomography. App. Phys. Lett. 81, 1180-1182, 2002.

Markel, V. and Schotland, J. Inverse Problem in Optical Diffusion Tomography. II. Role of Boundary Conditions. J. Opt. Soc. Am A 19, 558, 2002.

Markel, V. and Schotland, J. Scanning Paraxial Optical Tomography. Opt. Lett. 27, 1123, 2002.


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Warren D. Seider

Professor of Chemical and Biomolecular Engineering
Email: seider at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Process analysis, simulation, design, and control. Multiphase equilibria and azeotropic distillations, design and operation at unstable steady states, controller verification under uncertainty, Czochralski crystallization.

Multiphase Equilibria and Azeotropic Distillations: Advances in the calculation of multiphase equilibria are crucial for the successful simulation of heterogeneous azeotropic distillation towers, especially in the presence of salt-water solutions, where electrolytic reactions can lead to salting-out on the trays. Hence, a focus of our work is on the implementation of stability analysis, using the tangent-plane-distance function, to better locate trial phases for the minimization of the Gibbs free energy. In the design and control of these towers, the interfaces between trays having two- and one-liquid phases(s) are very sensitive to the reflux rate. We seek improved strategies for studying the dynamics of these towers and the existence of multiple steady states under normal operating conditions.

Design and Operation at Unstable Steady States: Many processes have been overdesigned because engineers are reluctant to design near or within regimes of complex operations, where they are often economically optimal. This is prevalent in processes with exothermic and autocatalytic reactions and where phases appear and disappear, especially in the critical region. We are developing designs that operate more economically closer to these nonlinear regimes, which are characterized by multiple steady states, periodic and even chaotic operation, often exhibiting inverse response. Improved control strategies are being developed to permit reliable operation near these regimes.

Controller Verification Under Uncertainty: To deal with uncertainties in process design and control, we are developing strategies for the verification of the stability and performance of controllers. Emphasis is placed on situations when both parametric and non-parametric uncertainties exist in the process model. In one approach, a qualitative reasoning technique, using symbolic manipulation, is being created to construct bounding equations. We are also developing a non-parametric Monte Carlo technique. These techniques are being applied for the automatic verification of control actions to prevent the process from straying into hazardous regimes in the face of large disturbances and faults.

Plant Design for Ease of Transition: Through the design of multi-product plants, using the same equipment, capital expenditures are often reduced. In continuous processing, transitions from one product to another are carried out often without shutting down the process; for example, in gas-phase, co-polymerization plants. We seek design strategies that simplify the transitions between many different product grades. To accomplish this, design optimizations account for transition costs, in addition to the costs of steady-state operation. Strategies involving the optimal sequencing of transitions are being developed; for example, to select among scenarios involving the manufacture of products A, C, and B, in sequence, rather than the manufacture of products A, B, and C, in sequence. Objectives include the reduction of transition times and off-specification product.

Selected Recent Publications:
Panjapornpon, C., Soroush, M., and Seider, W.D. A model-based control method applicable to unstable, non-mininum-phase, nonlinear processes. Proceedings of the American Control Conference, v 4, 2004, p 2921-2924.

Lewin, D. R., W. D. Seider, and J. D. Seader. Towards Integrating Design and Control for Defect-free Products. in Chapter D3, The Integration of Design and Control, Eds., P. Seferlis, and M. Georgiades, Elsevier Science, Amsterdam, 2004.

Panjapornpon, C., M. Soroush, and W. D. Seider. A Method of Controlling Unstable, Non-minimum-phase, Nonlinear Processes. IFAC ADCHEM 2003 Symposium, Hong Kong, January 13, 2004.

Seider, W. D., J. D. Seader, and D. R. Lewin. Chemical Product and Process Design Education. Proceedings of FOCAPD-2004 Conference, Princeton Univ., 2004.

Seider, W. D., J. D. Seader, and D. R. Lewin. PSE and Business Decision-Making in the Chemical Engineering Curriculum. Proceedings of PSE-2003 Symposium, Kunming, China, 2004.

Seider, W. D., J. D. Seader, and D. R. Lewin. Product and Process Design Principles: Synthesis, Analysis, and Evaluation. Second Edition, John Wiley, 2004.

Lewin, D. R., W. D. Seider, J. D. Seader, E. Dassau, J. Golbert, D. N. Goldberg, M. J. Fucci, and R. B. Nathanson. Using Process Simulators in Chemical Engineering: A Multimedia Guide for the Core Curriculum, Version 2.0, distributed by John Wiley, 2003.

Kanter, J. M., M. Soroush, and W. D. Seider. Nonlinear Controller Design for Input-Constrained, Multivariable Processes. Ind. Eng. Chem. Res., 41, 3735-3744, 2002.

Kanter, J. M., M. Soroush, and W. D. Seider. Nonlinear Feedback Control of Multivariable Non-minimum-phase Processes. J. Proc. Cont., 12, 6, 667-686, 2002.

Kanter, J. M., M. Soroush, and W. D. Seider. Real-time, Nonlinear Control of a Constrained, Non-minimum-phase Process. AIChE Journal, 48, 10, 2247-2254, 2002.

Lewin, D. R., W. D. Seider, and J. D. Seader. Integrated Process Design Instruction.Comput. Chem. Eng., 26, 295-306, 2002.


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Jianbo Shi

Assistant Professor of Computer and Information Science
Email: jshi at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
My primary research interests are in computer vision. I am also very interested in more general questions in AI and machine learning. My current research topics include:

Human Recognition: We are developing computer algorithms to recognize human at multiple levels of abstractions: from the basic body limb tracking, to human identification, to gesture recognition, to activity inference. The ultimate goal is to develop computation algorithms to understand human behavior in video.

Image Segmentation and Object Recognition: Our research is motivated by two sets of questions,1) how to extract “interesting” patterns from data, and 2) how to guide the grouping process to achieve specific vision tasks, such as recognizing familiar object shapes. In this direction, we have been pursuing a line of research building upon spectral graph theory.

Selected Recent Publications:
Efros, A., Isler, V., Shi, J. and Visontai, M. Seeing through Wather. NIPS 2005.

Benezit, F., Cour, T., and Shi, J. Spectral Segmentation with Multi-Scale Graph Decomposition. CVPR 2005.

Cour, T., Shi, J., and Gogin, N. Learning Spectral Graph Segmentation. AISTAT 2005.

Zhong, H., J. Shi and M. Visontai, Detecting Unusual Events in Video, IEEE Conf. on Computer Vision and Pattern Recognition (CVPR), Washington, D.C., June, 2004.

Gao, J. and J. Shi. Multiple Frame Motion Inference Using Belief Propagation, IEEEInternational Conference on Automatic Face and Gesture Recognition, May, 2004.

Yu, S. and J. Shi. Segmentation Given Partial Grouping Constraints. IEEE Transactions on Pattern Analysis and Machine Intelligence, 26(2):173-83, 2004.

Yu, S. and J. Shi. Multiclass Spectral Clustering, International Conference on Computer Vision(ICCV), Nice, France, October 11-17, 2003.

Takao, N., J. Shi, and S. Baker. Tele-Graffiti: A Camera-Projector Based Remote Sketching System with Hand-Based User Interface and Automatic Session Summarization, International Journal of Computer Vision, 53(2):115-133, July, 2003.

Yu, S. and J. Shi. Object-Specific Figure-Ground Segregation, IEEE Conf. on Computer Vision and Pattern Recognition (CVPR), Wisconsin, June 16-22, 2003.

Robert Collins, Ralph Gross, Jianbo Shi. Silhouette-based Human Identification from Body Shape and Gait. The 5th International conference on Automatic Face and Gesture Recognition, May 2002.

S. Yu and R. Gross and J. Shi. Concurrent Object Segmentation and Recognition with Graph Partitioning, Neural Information Processing Systems, NIPS, 2002.


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Wen K. Shieh

Professor of Chemical and Biomolecular Engineering
Email: shieh at seas.upenn.edu
Personal Website

Research Interests:
Bioenvironmental engineering, biological nitrogen removal, environmental systems modeling.

Selected Recent Publications:
Shieh, Wen K., Tsao, Yachi. Analysis of immobilized cell responses to substrate impulses. Biochemical Engineering Journal, v 18, n 3, June, 2004, p 177-184.

Shieh, Wen K., Tsao, Yachi. Impulse responses of a monoethylamine-fed fluidized bed reactor. Water Research, v 37, n 10, May, 2003, p 2331-2338.

Chen, J.C., Chang, N.B., Shieh, W.K. Assessing wastewater reclamation potential by neural network model. Engineering Applications of Artificial Intelligence, v 16, n 2 SPEC., March, 2003, p 149-157.

Shieh, Wen K., Weiss, Leon, Tai, Shu K. Methods and apparatus for biological treatment of aqueous waste. U.S. Pat. Appl. Publ., 16 pp, 2002.


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Barry Silverman

Professor of Electrical and Systems Engineering; Professor of Computer and Information Science; Professor of General Internal Medicine; Professor at Wharton/OPIM; Director, Ackoff Center for Advancement of Systems Approaches (ACASA), Core Faculty Member, Institute for Research in Cognitive Science; Senior Fellow, Leonard Davis Institute for Health Economics; Core Faculty Member, Center for Human Modeling and Simulation
Email: barryg at seas.upenn.edu
Personal Website

Research Interests:
Complex systems science and the knowledge management life cycle (story generator systems); human performance support and human learning in cyberspace; intelligent agent cognitive modeling and agent based simulation/artifical life; medical/health informatics and edutainment intervention designs.

Selected Recent Publications:
Silverman, BG. Human Performance Simulation. Ch.9 in J.Ness, D.Ritzer, V.Tepe (eds.), The Science and Simulation of Human Performance, NY: Elsevier, Jan. 2005.

van Lent M, McAlinden R, Brobst P, Silverman, BG. Enhancing the Behaviorial Fidelity of Synthetic Entities with Human Behavior Models.13th Conf on Behavior Representation in Modeling and Simulation (BRIMS), SISO, 12-15 May 2004. (Winner of an Outstanding Paper Award)

Silverman, BG, Johns, M, Cornwell, J, O'Brien, K. Human Behavior Models for Agents in Simulators and Games: Part I - Enabling Science with PMFserv. submitted to PRESENCE, 3/04.

Silverman, BG, Johns, M, Cornwell, J, O'Brien, K. Human Behavior Models for Agents in Simulators and Games: Part II - Gamebot Engineering with PMFserv. submitted to PRESENCE, 3/04.

Silverman, BG, Johns, M, Weaver, R., Mosley, J. Understanding the Technology for Learning-Based Interactive Dramas: The Authoring Edutainment Stories for Online Players (AESOP) Generator, submitted to J. of Game Development, 2004.

Silverman, BG, Johns, M, Weaver, R., Mosley, J. Authoring Edutainment Stories for Online Players (AESOP): Introducing Gameplay into Interactive Dramas. Internat'l Conference on Virtual Storytelling, Toulouse, FR: Springer, Nov 2003.

Cornwell, J., O'Brien, K., Silverman, BG, Toth, J. Affordance Theory for Improving the Rapid Generation, Composability, and Reusability of Synthetic Agents and Objects. 12th Conf on Behavior Representation in Modeling and Simulation (BRIMS, formerly CGF), SISO, 12-15 May 2003.

Silverman, BG, Johns, M, Weaver, R. Satisfying the Perceived Need for Free-Play in Pedagogically Oriented Interactive Dramas. Conference on Animated and Social Agents Proceedings., New York: IEEE Press, May 2003.

Toth J, Van Lent, M, Silverman, B., et al. Leveraging gaming in DOD modeling and simulation: Integrating performance and behavior moderator functions into a general cognitive architecture of playing and non-playing characters.12th Conf on Behavior Representation in Modeling and Simulation (BRIMS, formerly CGF), SISO, 12-15 May 2003.

Silverman, BG, Johns, M, Weaver, R, O'Brien, K, Silverman, R. Human Behavior Models for Game-Theoretic Agents. Cognitive Science Quarterly, v.2, n. 3/4, Fall '02, pp. 273-301.

Cornwell, J., Silverman, BG, et al. A Demonstration of the PMF-Extraction Approach: Modeling The Effects of Sound on Crowd Behavior. 11th Conf. On Computer Generated Forces and Behavioral Representation, SISO, May 2002. (Winner of an Outstanding Paper Award)

Silverman, BG, Holmes, J, Kimmel, S, Branas, C. Computer Games May Be Good for Your Health. HIMMS J. Healthcare Info Mgt, v.16,n.2, Spring '02, pp. 80-85.

Silverman, BG, Johns, M., et al.Constructing Virtual Asymmetric Opponents from Data and Models in the Literature: Case of Crowd Rioting. 11th Conf. On Computer Generated Forces and Behavioral Representation, SISO, May 2002. (Winner of an Outstanding Paper Award)

Silverman, BG, Holmes, J, Kimmel, S., et al. Decision Theoretic Emotion Models for Pedagogical Agents in Virtual Reality Games for Healthcare Behavioral Shifting. Ch. 9 in L.Jain (ed), Intelligent Agents and Their Applications, New York: Springer-Verlag, 2002, pp. 250-88.


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Talid R. Sinno

Associate Professor of Chemical and Biomolecular Engineering
Email: talid at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Transport and Reaction in Electronic Materials Processing, Atomistic Simulation for Structure and Property Estimation, Computational and Statistical Mechanical Modeling of Multiscale Phenomena. An important class of materials under current investigation are crystalline semiconductors used as substrates for electronic device fabrication. The quantitative characterization and understanding of their properties as a function of processing conditions is becoming more important as the requirements on purity and uniformity become more stringent. The driving force for these trends is the increasing size and complexity of today's electronic devices. Ideally, knowledge of a material's electronic structure in time as a function of the macroscopic environment would lead to an exact solution to any quantitative question. This, however, is not feasible because the time and length scales that characterize electron dynamics are many orders of magnitude smaller than those that define the macroscale. This issue is central in computational materials research; solutions have thus required the design of multi-scale approaches, typically consisting of separate, focused calculations linked via the exchange of property information between the different time and length scales.

Mesoscale Computation in Solid State Systems: Methods for continuum (O(1 cm)) and atomistic (O(1 nm) scale simulations are well defined. Unfortunately most solid state features relevant to the microelectronics industry lie somewhere in between at the micron length scale. There is great interest in either extending the traditional methods (such as finite element and molecular dynamics simulation) to these scales with parallel computers and faster algorithms, or meshing the two approaches together in what are now referred to as quasicontinuum simulations.

Interfacial and Surface Microscale Phenomena: Lack of a clear physical characterization of boundary conditions is a serious limitation in most solid state transport and reaction models. Currently, inaccurate boundary condition representations are disguised by parameter fitting which usually limits the predictive ability of the model. The issue of microscopically non-homogeneous defect incorporation is becoming more important as defect tolerances become more stringent because peak defect levels can become limiting even though the average level is acceptable. Wafer manufacturers are now investigating the formation of striations with experiments aimed at varying the microscopic growth pattern by altering the convective flow field in the melt. The mechanism of crystal defect formation across a solidification front remains largely unknown and is critically important as a focus of research for the crystal growth industry.

Thermodynamics and Chemistry of Impurities in Silicon: The advent of sophisticated, yet computationally tractable, interatomic potentials for investigating thermodynamics and structure of very small defects will be critical for filling the gaps that experimental measurements leave behind. Of particular current interest is the use of empirical tight-binding (TB) schemes in atomistic simulations of pure and impurity-doped silicon. TB simulation offers the best of both worlds in terms of accuracy and computational expense. TB schemes consider explicitly the electronic structure component in materials modeling without the tremendous expense of fully ab initio calculations. These simulations are starting to provide fairly accurate estimates for many thermophysical properties that are very difficult to obtain by any other method.

Selected Recent Publications:
M. Prasad and T. Sinno, Feature Activated Molecular Dynamics: Parallelization and Application to Systems with Globally Varying Mechanical Fields, in press: Journal of Computer-Aided Molecular Design.

S. Kapur, M. Prasad, J. C. Crocker, and T. Sinno, On the Configurational Entropy of Atomic Clusters in Crystalline Solids, PHYSICAL REVIEW B, 72 (1): Art. No. 014119 JUL 2005.

J. Dai, J. Kanter, S. Kapur, W. D. Seider, and T. Sinno, On-Lattice Kinetic Monte Carlo Simulations of Point Defect Aggregation in Entropically Influenced Crystalline Systems, submitted to Physical Review B.

T. Frewen, M. Prasad, W. Haeckl, W. von Ammon and T. Sinno, A Microscopically Accurate Continuum Model for Void Formation During Semiconductor Silicon Processing, Journal of Crystal Growth, 279 (2005) 258-271.

T. A. Frewen, T. Sinno, W. Haeckl, and W. von Ammon. A Systems-Based Approach for Generating Quantitative Models of Microstructural Evolution in Silicon Materials Processing. Computers and Chemical Engineering, v 29, n 4, March 2005, Control of Multiscale and Distributed Process Systems, p 713-730.

T. Sinno, T.A., Frewen, W. Haeckl, W. von Ammon. Systems-based Approach for Quantitative Modeling of Point Defect Transport and Reaction in Silicon. Proceedings of the 4th International Symposium on Advanced Science and Technology of Silicon Materials, JSPS, 2004.

S. Kapur, M. Prasad, and T. Sinno. Carbon-Mediated Aggregation of Self-Interstitials in Silicon. Physical Review B 69, 2004,155214 1-8.

M. Prasad and T. Sinno. Feature-Activated Molecular Dynamics: An Efficient Approach for Atomistic Simulations of Aggregation in Solids. Journal of Chemical Physics, 05/2004.

T. Sinno and M. Prasad. Internally Consistent Verification of Mean-Field Models of Aggregation using Large-Scale Molecular Dynamics. Molecular Physics 102, 2004, 395-403.

T. Frewen, T. Sinno, E. Dornberger, R. Hoelzl, W. von Ammon, and H. Bracht. Parameterization of Transient Defect Dynamics Models in Czochralski Silicon Crystal Growth. Journal of the Electrochemical Society 150, 2003, G673-G682.

M. Prasad and T. Sinno. An Internally Consistent Approach for Modeling Solid-State Aggregation: I. Atomistic Calculations of Vacancy Clustering in Silicon. Physical Review B 68, 2003, 45206 1-12.

M. Prasad and T. Sinno. An Internally Consistent Approach for Modeling Solid-State Aggregation: II. Mean-field Representations of Atomistic Processes. Physical Review B 68, 2003, 45207 1-13.

M. Prasad and T. Sinno. An Atomistic to Continuum Description of Vacancy Cluster Properties in Crystalline Silicon. Applied Physics Letters, 80, 2002, 1951-1953.


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Jonathan M. Smith

Olga and Alberico Pompa Professor of Computer and Information Science
Email: jms at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
Distributed systems, operating systems, multimedia communications systems, applications of randomness, computer security, and cryptology.

Selected Recent Publications:

Yun Mao, Bjorn Knutsson, Honghui Lu, and Jonathan M. Smith. DHARMA: Distributed Home Agent for Robust Mobile Access. Proceedings, INFOCOM 2005, to appear.

Noriyuki Takahashi and Jonathan M.Smith. Hybrid Hierarchical Overlay Routing (Hyho): Towards Minimal Overlay Dilaion. IEICE Transactions Inf. and Syst. (Special Issue on New Technologies and their Applications of the Internet), Vol. E2004-D(12), to appear, December 2004.

Dirk Bergemann, Joan Feigenbaum, Scott Shenker, and Jonathan M. Smith. Towards An Economic Analysis of Trusted Systems. Proceedings, 3rd Annual Workshop on Economics and Information Security, May 13-14, 2004.

Jonathan M. Smith. Application-Private Networks. in Computer Systems: Theory, Technology and Applications: A Tribute to Roger Needham, ed. Andrew Herbert and Karen Sparck Jones, Springer-Verlag, 2004, pp. 273-278. This first appeared in February 2003 on pages 227-231 in COMPUTER SYSTEMS: Papers for Roger Needham, a private printing, but available at http://www.research.microsoft.com/~aherbert/volume.pdf.

Jonathan M. Smith and Scott M. Nettles. Realizing SwitchWare.Programmable IP Networks: Managementand Rapid Service Deployment, ed. A. Galis, S. Denazis, C. Brou, and C.Klein, Artech House, May 2004 ISBN 1580537456.

Jonathan M. Smith. Programmable Networks Security: Background. Programmable IP Networks: Management and Rapid Service Deployment, ed. A. Galis, S. Denazis, C. Brou, and C.Klein, Artech House, May 2004, ISBN 1580537456.

M.DeYoung, N. Henke, G. Wai, and J. Smith. Rethinking Mobile Telephony with the IMP. in Proceedings, European Wireless, Barcelona, SPAIN, February, 2004, pp. 378-386.

Jonathan M. Smith, Michael B. Greenwald, Sotiris Ioannidis, Angelos D. Keromytis, Ben Laurie, Douglas Maughan, Dale Rahn, and Jason Wright. Experiences Enhancing Open SourceSecurity in the POSSE Project. in Free/Open Source Software Development, ed. Stefan Koch, Idea Group Publishing, Hershey, PA, 2004, pp. 242-257. ISBN 1-59140-369-3.

Jonathan M. Smith and Scott M. Nettles. Active Networking: One View of the Past, Present and Future. IEEE Transactions On Systems, Man and Cybernetics, Part C: Applications and Reviews, Vol. 34(1), pp. 4-18, February 2004.

Ilija Hadzic and Jonathan M. Smith. Balancing Performance and Flexibility with Hardware Support for Network Architectures. ACM Transactions on Computer Systems, Vol. 21(4)pp. 375-411, November 2003.

Angelos D. Keromytis, Kostas Anagnostakis, Sotiris Ioannidis, Michael B. Greenwald, and Jonathan M. Smith. Managing Access Control in Large Scale Heterogenous Networks. Proceedings, Interoperable Networks for Secure Communications Symposium (NATO), Hague, The Netherlands, November 4-6, 2003.

Jonathan M. Smith. At Issue: Should software manufacturers be liable for vulnerabilities in their software? CQ Researcher, p. 811, Congressional Quarterly Press, (Affirmative Position) September 26, 2003.

Michael Hicks, Angelos D.Keromytis, and Jonathan M. Smith. A Secure PLAN (Extended Version). IEEE Transactions On Systems, Man and Cybernetics, Part C: Applications and Reviews, Vol. 33(3), pp. 413-426, August 2003.

Sotiris Ioannidis, Steven M. Bellovin, John Ioannidis, Angelos Keromytis, and Jonathan M. Smith/Design and Implementation of Virtual Private Services," in Proceedings of the IEEE International Workshops on Enabling Technologies: Infrastructure for Collaborative Enterprises (Workshop on Enterprise Security, Special Session on Trust Management in Collaborative Global Computing), June, 2003. Earlier version available as U Penn. CIS Technical Report MS-CIS-01-13.

Stefan Miltchev, Vassilis Prevelakis, Sotiris Ioannidis,John Ioannidis, Angelos D. Keromytis, and Jonathan M. Smith. Secure and Flexible Global File Sharing. in Proceedings,USENIX 2003 (FREENIX track), June 2003, pp. 165-178.

F. Herz, J. Smith, and D. Parkes. Location Enhanced Information Delivery System. U.S. Patent No. 6,571,279, May 27, 2003.

Angelos D. Keromytis, Sotiris Ioannidis, Michael B. Greenwald, and Jonathan M. Smith. The STRONGMAN Architecture. In Proceedings, DARPA Information Survivability Conference and Exhibition, IEEE Press, Washington, DC, April 22-24 2003, pp. 178-188. ISBN 0-7695-1897-4.

James Alexander and Jonathan Smith. Engineering Privacy in Public: Confounding Face Recognition. In Privacy Enhancing Technologies, Third International Workshop, PET 2003, Dresden, Germany, March 26-28, 2003, Revised Papers, ed. Roger Dingledine, Springer-Verlag, Dresden, Germany, 2003, pp. 88-106. ISBN 3-540-20610-8.

Jonathan M. Smith. Gigabit Networks. in The Communications Handbook, Second Edition. ed. Jerry D. Gibson, CRC Press, 2002, pp. 38-1-38-8. ISBN 0-8493-0967-0

Jonathan M. Smith. The Impact of ATM on Operating Systems. ACM Computer Communications Review, Vol. 32(5), pp. 29-37. November, 2002.

Sotiris Ioannidis, Steven M. Bellovin, and Jonathan M. Smith. Sub-Operating Systems: A New Approach to Application Security. In 10th SIGOPS European Workshop, September, 2002.

Michael Hicks, Angelos D. Keromytis, and Jonathan M. Smith. A Secure PLAN (Extended Version). in Proceedings, DARPA Active Networks Conference and Exposition, IEEE Computer Society Press San Francisco, CA, May 29-30, 2002, pp. 224-237.

K.G. Anagnostakis, S. Ioannidis, S. Miltchev, J. Ioannidis, M. Greenwald, and J. M. Smith. Efficient Packet Monitoring for Network Management. in Proceedings, IEEE NOMS, Florence, IT, April 2002, pp. 423-436.


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Tony E. Smith

Professor of Electrical and Systems Engineering; Professor of Regional Science
Email: tesmith at seas.upenn.edu
Personal Website

Research Interests:
Primary area of research is in the theory and application of probabilistic models to spatial interaction behavior. Specific interests focus on structural analysis and axiomatic foundations of such models. Related areas of interest are in probabilistic theories of choice behavior, spatial statistical analysis and GIS. A secondary area of research is in transportation and land use modeling. Specific interests focus on network equilibrium models of traffic flows and general equilibrium models of urban land use.

Selected Recent Publications:

Smith, Tony E. Aggregation Bias in Maximum-Likelihood Estimation of Spatial Autoregressive Processes. Spatial Econometrics and Spatial Statistics, 2004 pp 53-88.

Smith, Tony E. A Scale-Sensitive Test of Attraction and Repulsion between Spatial Point Patterns. Geographical Analysis, 36(4), October 2004, p 315-331.

Smith, Tony E , Song, Sangyoung. A Spatial Mixture Model of Innovation Diffusion. Geographical Analysis, 36(2), April 2004, p 119-145.

Smith, Tony E , Zenou, Ives. Spatial Mismatch, Search Effort and Urban Spatial Structure. Journal of Urban Economics, 54(1), July 2003, p 129-156.

T. Smith, Y. Zenou. A Discrete-Time Stochastic Model of Job Matching. Review of Economic Dynamics, 6: 54-79, 2003.

Tomoya Mori, Koji Nishikimi, and Tony E. Smith. Some Empirical Regularities of Spatial Economies: A Relationship between Industrial Location and City Size, 2003.

T. Smith, A.E. Hillier, D.P. Culhane, and C.D. Tomlin. Predicting Housing Abandonment with the Philadelphia Neighborhood Information System. Journal of Urban Affairs, 25(1): 91-105 , 2002.

Smith, Tony E , James P. LeSage. A Bayesian Probit Model with Spatial Dependencies, 2002.


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Oleg Sokolsky

Research Assistant Professor of Computer and Information Science
Email: sokolsky at cis.upenn.edu
Personal Website

Research Interests:
My main research interest is the application of formal methods to design and verification of distributed real-time systems. Other interests, all related to the main one, include on-line monitoring of distributed systems and formal foundations for it, hybrid systems, automated extraction of specifications from source code, and formal methods in software engineering in general and in embedded software in particular.

Selected Recent Publications:
Usa Sammapun, Arvind Easwaran, Insup Lee, and Oleg Sokolsky. Simulation of Simultaneous Events in Regular Experessions for Run-Time Verification. Electronic Notes in Theoretical Computer Science, v 113, n SPEC. ISS., Jan 3 2005, p 123-143.

Li Tan, Jesung Kim, Oleg Sokolsky, and Insup Lee. Model-based testing and monitoring for hybrid embedded systems. IEEE International Conference on Information Reuse and Integration, 2004, p 487-492.

Li Tan, Oleg Sokolsky and Insup Lee. Specification-based testing with linear temporal logic. IEEE International Confernce on Information Reuse and Integration, 2004, p 493-498.

Margaret Delap, Bjorn Knutsson, Honghui Lu, et al. Is runtime verification applicable to cheat detection. In Proceedigns of the ACM SIGCOMM 2004 Workshops, 2004, p 134-138.

Oleg Sokolsky. Resource modeling for embedded systems design. IEEE Workshop on Software Technologies for Future Embedded and Ubiquitous Systems, 99-103.

Kim, Moonzoo, Viswanathan, Mahesh, Kannan, Sampath, Lee, Insup, Sokolsky, Oleg. Java-MaC: A Run-Time Assurance Approach for Java Programs. Formal Methods in System Design, v 24, n 2, March, 2004, p 129-155.

Alur, R., Thao Dang, Esposito, J., Yerang Hur, Ivancic, F., Kumar, V., Mishra, P., Pappas, G.J., Sokolsky, O. Hierarchical modeling and analysis of embedded systems. Proceedings of the IEEE, v 91, n 1, Jan. 2003, p 11-28.

Alur, Rajeev, Ivancic, Franjo, Kim, Jesung, Lee, Insup, Sokolsky, Oleg. Generating embedded software from hierarchical hybrid models. Proceedings of the ACM SIGPLAN Conference on Languages, Compilers, and Tools for Embedded Systems (LCTES), 2003, p 171-182.

Hong, Hyoung Seok, Cha, Sung Deok, Lee, Insup, Sokolsky, Oleg, Ural, Hasan. Data flow testing as model checking. Proceedings - International Conference on Software Engineering, 2003, p 232-242.

Alur, R., Belta, C., Ivancic, F., Vijay Kumar, Rubin, H., Schug, J., Sokolsky, O., Webb, J. Visual programming for modeling and simulation of biomolecular regulatory networks. High Performance Computing - HiPC 2002. 9th International Conference. Proceedings (Lecture Notes in Computer Science Vol.2552), 2002, p 702-12.

I. Lee, A. Philippou, and O. Sokolsky. A General Resource Framework for Real-Time Systems, Workshop on Radical Innovations of Software and Systems Engineering in the Future. Lecture Notes in Computer ScienceVol.2941, October 2002, p. 234-48.

Lee, Insup, Philippou, Anna, Sokolsky, Oleg. Process algebraic modelling and analysis of power-aware real-time systems. Computing and Control Engineering Journal, v 13, n 4, August, 2002, p 180-188.

H. Hong, I. Lee, O. Sokolsky, and H. Ural. A Temporal Logic Based Theory of Test Coverage and Generation. International Conference on Tools and Algorithms for Construction and Analysis of Systems (TACAS2002), April 8-11, 2002, p.327-41.

K. Bhargavan, C.A. Gunter, M. Kim, I. Lee, D. Obradovic, O. Sokolsky, and M. Viswanathan. Verisim: Formal Analysis of Network Simulations,'' Transactions on Software Engineering.Vol. 28, No. 2, Feb. 2002, pp. 129-145. Preliminary version appeared in the Proceedings of ISSTA'00.

H.-H. Kwak, I. Lee and O. Sokolsky. Parametric approach to the specification and analysis of real-time scheduling based on ACSR-VP. Science of Computer Programming, Vol. 42, Issue 1, Jan 2002, pp. 49--60.

Moonjoo Kim, Kannan, S., Insup Lee, Sokolsky, O., Viswanathan, M. Computational analysis of run-time monitoring - fundamentals of Java-MaC. Electronic Notes in Theoretical Computer Science, v 70, n 4, 2002.

Moonjoo Kim, Insup Lee, Sammapun, U., Jangwoo Shin, Sokolsky, O. Monitoring, checking, and steering of real -time systems. Electronic Notes in Theoretical Computer Science, v 70, n 4, 2002.


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Louis J. Soslowsky

Vice Chair of Research of Department of Orthopaedic Surgery, Director of McKay Orthopaedic Research Lab, Associate Professor of Orthopaedic Surgery, Associate Professor of Bioengineering, Graduate Group Member in Bioengineering and Mechanical Engineering and Applied Mechanics
Email: soslowsk at mail.med.upenn.edu
Personal Website   |   Research Website

Research Interests:
Orthopaedic Bioengineering, Functional Tissue Engineering, Structure-Function Relationships of Tendons and Ligaments, Models for Tendon Injury, Healing, Repair, and Regeneration, Biomechanics of the Shoulder

Selected Recent Publications:
Barton, E.R., Gimbel, J.A., Williams, G.R., Soslowsky, L.J.: Rat supraspinatus muscle atrophy after tendon detachment. Journal of Orthopaedic Research, 23(2): 259-65, March 2005.

Perry, S.M., McIlhenny, S.E., Hoffman, M.C., Soslowsky, L.J.: Inflammatory and angiogenic mRNA levels are altered in a supraspinatus tendon overuse animal model. Journal of Shoulder & Elbow Shoulder, 14(1 Suppl): 79S-83S, January-February 2005.

Yokota, A., Gimbel, J.A., Williams, G.R., and Soslowsky, L.J.: Supraspinatus tendon composition remains altered long after tendon detachment. Journal of Shoulder & Elbo Surgery, 14 (1 Suppl S): 72S-78S, January-February 2005.

Kuhn, J.E., Huston, L.J., Soslowsky, L.J., Shyr, Y., and Blasier, RB.: External rotation of the glenohumeral joint: ligament restraints and muscle effects n the neutral and abducted positions: Journal of Shoulder & Elbow Surgery, 14(1 Suppl S): 29S-48S, January-February 2005.

Robinson, P.S., Huang, T.F., Kazam, E., Iozzo, R.V., Birk, D.E., and Soslowsky, L.J.: Influence of decorin and biglycan on mechanical properties of multiple tendons in knockout mice. Journal of Biomechanical Engineering, v 127, n 1, February 2005, p 181-185.

Lin, T.W., Cardenas, L., and Soslowsky, L.J.: Tendon properties in interleukin-4 and interleukin-6 knockout mice. Journal of Biomechanics, v 38, n 1, January 2005, p 99-105.

Zhang, G., Young, B.B., Ezura, Y., Favata, M., Soslowsky, L.J., Chakravarti, S., and Birk, D.E.: Development of tendon structure and function: Regulation of collagen fibrillogenesis. J Musculoskeletal Neuronal Interactions, in press 2004.

Gimbel, J.A., Sarver, J.J., and Soslowsky, L.J.: The effect of overshooting the target strain on estimating viscoelastic properties from stress relaxation experiments. Journal of Biomechanical Enginering, v 126, n 6, December 2004, p 844-848.

Gimbel, J.A., Van Kleunen, J.P., Mehta, S., Perry, S.M., Williams, G.R., and Soslowsky, L.J.: Supraspinatus tendon structural and mechanical properties in a chronic rotator cuff tear animal model. J Biomechanics, 37:739-749, 2004

Gimbel, J.A., Mehta, S., Van Kleunen, J.P., Williams, G. R., and Soslowsky, L.J.: The tension required at repair to re-appose the supraspinatus tendon to bone rapidly increases following injury. Clin Orth Rel Res, (426)258-65, September 2004

Huang, T.F., Perry, S.M., and Soslowsky, L.J.: Achilles vs supraspinatus tendon changes due to treadmill running in an animal model, Annals Biomed Eng, 32:336-341, 2004

Lin, T.W., Cardenas, L, and Soslowsky, L.J.: Biomechanics of tendon injury and repair. J Biomechanics, 37:865-877, 2004

Huang, T.F., Perry, S.M., and Soslowsky, L.J.: The effect of overuse activity on Achilles tendon in an animal model: A biomechanical study. Annals of Biomedical Engineering, v 32, n 3, March 2004, p 336-341.

Robinson, P.S., Lin, T.W., Reynolds, P., Derwin, K., Iozzo, R., and Soslowsky, L.: Strain rate sensitive mechanical properties of tendon fascicles from mice with genetically engineered alterations in collagen and decorin. J Biomech Eng, 126:252-257, 2004

Robinson, Lin, T., P., Reynolds, P., Jawad, A., Iozzo, R., and Soslowsky, L.: Investigating tendon fascicle structure-function relationships in a transgenic-age mouse model using multiple regression models. Annals Biomed Eng, 32:924-931, 2004

Robinson, P.S., Placide, R., Soslowsky, L.J., and Born, C.T.: Mechanical strength of repairs of the hips short external rotators. J Arthroplasty, 19:204-210, 2004

Zhang, G.Y., Robinson, R.S., Soslowsky, L.J., et al.: Development of tendon structure and function in the decorin-deficient mouse: Relationship between decorin and biglycan expression. FASEB Journal, 18(5): A788-1789. Suppl. S., March 24 2004.
Beredjiklian, P.K., Favata, M., Cartmell, J.S., Flanagan, C.L., Crombleholme, T.M., and Soslowsky, L.J.: Regenerative vs. reparative healing in tendon: An in vivo study of biomechanical and histological properties in a fetal sheep model. Annals Biomed Eng, 31:1143-1152, 2003

Elliott, D.M., Robinson, P.S., Gimbel, J.A., Sarver, J.J, Abboud, J.A., Iozzo, R.V., and Soslowsky, L.J.: Effect of altered matrix proteins on quasilinear viscoelastic properties in transgenic mouse tail tendons. Annals Biomed Eng, 31:599-605, 2003

Kuhn, J.E., Lindholm, S.R., Huston, L.J., Soslowsky, L.J., and Blasier, R.B.: Failure of the biceps superior labral complex: A cadaveric biomechanical investigation comparing the late cocking and early deceleration positions of throwing. Arthroscopy, 19:373-379, 2003.

Mehta, S.M., Gimbel, J.A., and Soslowsky, L.J.: Etiologic and pathogenetic factors for rotator cuff tendinopathy. Clin Sports Med, 22:791-812, 2003

Thomopoulos, S., Williams, G.R., Gimbel, J.A., Favata, M., and Soslowsky, L.J.: Variation of biomechanical, structural and compositional properties along the tendon to bone insertion site. J Orthop Res, 21:413-419, 2003

Thomopoulos, S., Williams, G.R., and Soslowsky, L.J.: Tendon to bone healing: Differences in biomechanical, structural, and compositional properties due to a range of activity levels. J Biomech Eng, 125:106-113, 2003.

Abboud, J. and Soslowsky, L.J.: Interplay of the static and dynamic restraints in glenohumeral instability. Clin Orthop Rel Res, 400:48-57, 2002.

Abboud, J.A., Bozentka, D.J., Soslowsky, L.J., and Beredjiklian, P.K.: Cyclic loading properties of minisuture anchors in carpal bones. Proceedings of the American Academy of Orthopaedic Surgeons, Paper #186, 2002

Abboud, J.A., Bozentka, D.J., Soslowsky, L.J., and Beredjiklian, P.K.: Effect of implant design on the cyclic loading properties of mini suture anchors in carpal bones, J Hand Surg [Am], 27:43-48, 2002.

Bey M.J., Ramsey, M.L., and Soslowsky, L.J.: Intratendinous strain fields of the supraspinatus tendon: Effect of a surgically created articular-surface rotator cuff tear. J Shoulder Elbow Surg, 11:562-569, 2002.

Bey, M.J., Ramsey, M.L., and Soslowsky, L.J.: Intratendinous strain fields of the supraspinatus tendon: The effect of a surgically created articular-surface rotator cuff tear. American Shoulder and Elbow Surgeons Specialty Day, Paper #22, 2002

Bey M.J., Song, H.K., Wehrli, F.W., and Soslowsky, L.J.: Intratendinous strain fields of the intact supraspinatus tendon: The effect of glenohumeral joint position and tendon region. J Orthop Res, 20:869-874, 2002.

Bey M.J., Song, H.K., Wehrli, F.W., and Soslowsky, L.J.: A noncontact, nondestructive method for quantifying intratissue deformations and strains. J Biomech Eng, 124:253-258, 2002.

Bey, M.J. and Soslowsky, L.J.: Intratendinous strain fields of the supraspinatus tendon: The effect of a bursal side partial-thickness rotator cuff tear. Transactions of the Orthopaedic Research Society, 27:862, 2002

Bey, M.J., Squire, M.E., Ramsey, M.L., and Soslowsky, L.J.: The effect of radial head resection and replacement on strain fields of the anterior medial collateral ligament surface: A stereophotogrammetric study. Transactions of the Orthopaedic Research Society, 27:853, 2002

Elliott, D.M., Robinson, P.S., Gimbel, J.A., Sarver, J.J, Iozzo, R.V., and Soslowsky, L.J.: Quasi-linear viscoelastic modeling of tail tendons from transgenic mice. Proceedings of the World Congress of Biomechanics, 1326, 2002

Gamer, L., McDermott, K., Cox, K., Mertens, M., Soslowsky, L.J., and Rosen, V.: Molecular and cellular analysis of rotator cuff tendinosis in a rat model. Transactions of the Orthopaedic Research Society, 27:43, 2002

Gamer, L., McDermott, K., Cox, K., Mertens, M., Soslowsky, L.J., and Rosen, V.: Molecular and cellular analysis of rotator cuff tendinosis in a rat model. Proceedings of the World Congress of Biomechanics, 5236, 2002

Gimbel, J.A., Robinson, P.S., Abboud, J.A., Elliott, D.M., Iozzo, R.V., and Soslowsky, L J.: Determining the source of elasticity and viscoelasticity in transgenic mouse tendon fascicles. Transactions of the Orthopaedic Research Society, 27:603, 2002

Lin, T.W., White, S.M., Robinson, P.S., Derwin, K.A., Plaas, A., and Iozzo, R.V.: Relating extracellular matrix composition with function A study using transgenic mouse tail tendon fascicles. Transactions of the Orthopaedic Research Society, 27:45, 2002

Malicky, D.M., Kuhn, J.E., Frisancho, J.C., Lindholm, S.R., Raz, J.A., and Soslowsky, L.J.: Non-recoverable strain fields of the anteroinferior glenohumeral capsule under subluxation. J Shoulder Elbow Surg, 11:529-540, 2002 (2001 Neer Award Winner).

Thomopoulos, S., Hattersley, G., Rosen, V., Mertens, M., Galatz, L., Williams, G.R., and Soslowsky, L.J.: The localized expression of extracellular matrix components in healing tendon insertion sites: An in situ hybridization study. J Orthop Res, 20:454-463, 2002.

Soslowsky, L.J., Thomopoulos, S., Esmail, A., Flanagan, C.L., Iannotti, J.P., Williamson III, J.D., and Carpenter, J.E.: Rotator cuff tendinosis in an animal model: The role of extrinsic and overuse factors. Ann Biomed Eng, 30:1057-1063, 2002.

Thomopoulos, S., Williams, G.R., and Soslowsky, L.J.: Tendon to bone healing: Changes in structural, compositional, and biomechanical properties due to post-operative activity level. Transactions of the Orthopaedic Research Society, 27:148, 2002

Thomopoulos, S., Williams, G.R., and Soslowsky, L.J.: Variation of biomechanical structural and compositional properties along the tendon to bone insertion site. Transactions of the Orthopaedic Research Society, 27:246, 2002

Thomopoulos, S., Soslowsky, L.J., Flanagan, C.L., Tun, S., Keefer, C.C., Mastaw, J., and Carpenter, J.E.: The effect of fibrin clot on healing rat supraspinatus tendon defects. J Shoulder Elbow Surg, 11:239-247. 2002.


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Val Tannen

Professor of Computer and Information Science
Email: val at cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
Databases, bioinformatics, logic in computer science, programming languages, parallel computing.

Selected Recent Publications:

Deutsch, Alin, Tannen, Val. XML Queries and Constraints, Containment and Reformulation. Theoretical Computer Science, 2005.

Magkanaraki, Aimilia, Tannen, Val, Christophides, Vassilis, and Plexousakis, Dimitris. Viewing the Semantic Web Through RVL Lenses. Web Semantics, 2004.

Bunema, P. and Tannen, V. A Structural Approach to Query Language Design. The Functional Approach to Data Management: Modeling, Analyzing, and Integrating Heterogeneous Data, 2004.

Christophides, V., Karvounarakis, G., Magkanaraki, A., Plexousakis, D., and Tannen, V. The ICS-FORTH Semantic Web Integration Middleware (SWIM). Data Engineering Bull., Vol. 26, Dec 2003, pp 11-18.

Tannen, V., Davidson, S.B., and Harker, S. The Information Integration System K2. Bioinformatics: Managin Scientific Data, Elsevier, 2003.

Deutsch, Alin, Tannen, Val. MARS: A System for Publishing XML from Mixed and Redundant Storage. International Conference on Very Large Databases (VLDB), 2003.

Deutsch, Alin, Tannen, Val. Reformulation of XML Queries and Constraints. International Conference on Database Theory (ICDT), 2003.

Deutsch, Alin Tannen, Val. Querying XML with Mixed and Redundant Storage. Technical Report MS-CIS-02-01, 2002.


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Camillo J. Taylor

Associate Professor of Computer and Information Science; Associate Professor of Electrical and Systems Engineering
Email: cjtaylor at central.cis.upenn.edu
Personal Website   |   Research Website

Research Interests:
Computer vision to control mobile robots, recovering 3D models of rigid scenes from images.

Selected Recent Publications:
Erdinc Altug, James P. Ostrowski, and Camillo J. Taylor. Control of a quadrotor helicopter using dual camera visual feedback. International Journal of Robotics Research, v 24, n 5, May 2005, p 329-341.

Daniel Gomez-Ibanez, Ethan Stump, Benjamin Grocholsky, Vijay Kumar, Camillo J. Taylor. The robotics bus:A local communications bus for robots. Proceedings of SPIE – The International Society for Otpical Engineering, v 5609, Mobile Robots XVII, 2004, p 155-163.

Mong-Ying A. Hsieh, Pranav Srivastava, Vijay Kumar, and Camillo J. Taylor. Composable communcation constraint based control. Proceedings of SPIE – The International Society for Optical Engineering, v 5609, Mobile Robots XVII, 2004, p 102-2004.

Volkan Isler, Sanjeev Khanna, John Spletzer and Camillo J. Taylor. Target Tracking with Distributed Sensors: The Focus of Attention Problem. Submitted to Computer Vision and Image Understanding.

Luiz Chaimowicz, Ben Grocholsky, James F. Keller, Vijay Kumar and Camillo J. Taylor. Experiments in Multirobot Air-Ground Coordination. IEEE Conference on Robotics and Automation, 2004.

Anthony Cowley, Hwa-chow Hsu and Camillo J. Taylor. Distributed Databases for Multi-Robot Teams.IEEE Conference on Robotics and Automation, 2004.

Ben Grocholsky, Selcuk Bayraktar, Vijay Kumar, Camillo J. Taylor and George Pappas. Synergies in Feature Localization in Air-Ground Robot Teams. International Symposium on Experimental Robotics, ISER 04, 2004.

Ani Mong-ying Hsieh, Vijay Kumar and Camillo J. Taylor. Constructing Radio Signal Strength Maps. IEEE Conference on Robotics and Automation, 2004.

Rahul Rao, Vijay Kumar and Camillo Taylor. Experiments in Robot Control from Uncalibrated Overhead Imagery. International Symposium on Experimental Robotics ISER 04, 2004.

Rahul Rao, Camillo J. Taylor and Vijay Kumar. Calibrating an Air-Ground Control System from Motion Correspondences. IEEE Conference on Computer Vision and Pattern Recognition, 2004.

John Spletzer and Camillo J. Taylor. Convex Approximation Strategies for Multi-Robot Localization. Submitted to The Workshop on the Algorithmic Foundations of Robotics, 2004.

E. Altug, J. Ostrowski and C.J. Taylor. Quadrotor Control Using Dual Camera Visual Feedback. International Conference on Robotics and Automation (ICRA 03) pp 576-583, 2003.

Luiz Chaimowicz, Anthony Cowley, Vito Sabella and Camillo J. Taylor. ROCI: A Distributed Framework for Multi-Robot Perception and Control. IEEE/RSJ International Conference on Intelligent Robots and Systems, pp 266-273, 2003.

Volkan Isler, Sanjeev Khanna, John Spletzer and C.J. Taylor.Target Tracking with Distributed Sensors: The Focus of Attention Problem. IEEE/RSJ International Conference on Intelligent Robots and Systems, pp 792-798, 2003.

Sarangi Parikh, Rahul Rao, Sang-Hack Jung, Vijay Kumar, James Ostrowski and Camillo J. Taylor. Human Robot Interaction and Usability Studies for a Smart Wheelchair. IEEE/RSJ International Conference on Intelligent Robots and Systems, pp 3206-3212, 2003.

Rahul Rao, Vijay Kumar and Camillo J. Taylor. Image Based Control of Differentially Flat Systems. IEEE/RSJ International Conference on Intelligent Robots and Systems, pp 743-749, 2003.

John Spletzer, Camillo J. Taylor. Dynamic Sensor Planning and Control. International Journal of Robotics Research, Vol 22, No. 1 pp 7-21 January 2003.

John Spletzer and Camillo J. Taylor.A Bounded Uncertainty Approach to Multi-Robot Localization. IEEE/RSJ International Conference on Intelligent Robots and Systems, pp 1258-1264, 2003.

Camillo J. Taylor. Surface Reconstruction from Feature Based Stereo. International Conference on Computer Vision, pp 432, 2003.

R. Alur, A. Das, J. Esposito, R. Fierro, Y. Hur, G. Grudic, V. Kumar, I. Lee, J. P. Ostrowski, G. Pappas, J. Southall, J. Spletzer, and C. Taylor. A framework and architecture for multirobot coordination. International Journal of Robotics Research Vol. 21, No. 10-11, pp. 977-995, October-November 2002.

E. Altug, J. Ostrowski and C.J. Taylor. Quadrotor Control Using Dual Camera Visual Feedback. International Symposium on Experimental Robotics ISER 02, pp 37-43, 2002.

Aveek Das, Rafael Fierro, Vijay Kumar, Jim Ostrowski and C.J. Taylor. A Vision-Based Formation Control Framework. IEEE Transactions on Robotics and Automation, Vol. 18 No. 5 pp 813-826, October 2002

A. Das, J. Spletzer, V. Kumar and C. Taylor. Ad Hoc Networks for Localization and Control of Mobile Robots. IEEE Conf. on Decision and Control CDC02, pp 1024-1030, 2002.

David Jelinek and C.J. Taylor. View Synthesis with Occlusion Reasoning using Quasi-Sparse Feature Correspondences. European Conference on Computer Vision Copenhagen Denmark, Vol2 pp 463-492, May 2002.

S. Patel, S. H. Jung, J. Ostrowski,R. S. Rao,C. J. Taylor. Sensor Based Door Navigation for a Nonholonomic Vehicle. ICRA2002, IEEE Int.Conf. Robot. Autom., pp 3081-3087, 2002.

G. Pereira, V. Kumar, J. Spletzer, C.J. Taylor and M. Campos. Cooperative Transport of Planar Objects by Multiple Mobile Robots Using Object Closure. International Symposium on Experimental Robotics ISER 02, pp 78-84, 2002.

R.S. Rao, K.Conn, S.H. Jung, J. Katupitiya, T.Kientz, V.Kumar, J. Ostrowski, S. Patel, C.J. Taylor. Human Robot Interaction: Application to Smart Wheelchairs. ICRA2002, IEEE Int.Conf. Robot. Autom., pp 3583-3589, 2002.

John Spletzer and Camillo J. Taylor. A framework for sensor planning and control with applications to vision guided multi-robot systems. ICRA2002, IEEE Int.Conf. Robot. Autom., pp 676-682, 2002.

Camillo J. Taylor. VideoPlus: A Method for Capturing the Structure and Appearance of Immersive Environments. IEEE Transactions on Visualization and Computer Graphics Vol 8 No. 2 pp 171-183, April-June 2002.


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Andrew Tsourkas

Assistant Professor of Bioengineering, Member of the Institute of Medicine and Engineering, Secondary Appointment in Radiology
Email: atsourk at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Developing novel molecular imaging probes to study genetic and protein expression profiles via fluorescence, bioluminescence, and magnetic resonance imaging. Dr. Tsourkas' current research focuses on the detection of gene expression using novel oligonucleotide-based fluorescent probes, targeting molecular markers of disease with magneto-optical nanoparticles, and using molecular reporters to monitor cell signaling pathways.

Selected Recent Publications:

Tsourkas, A., Newton, G., Perez, J.M., Basilion, J.P., and Weissleder, R. Detection of peroxidase/H2O2-mediated oxidation with enhanced yellow fluorescent protein. Analytical Chemistry, v 77, n 9, May 1 2005, p 2862-2867.

Kelly, K., Allport, J., Tsourkas, A., Patel, P., Wolley, A., Shinde-Patil V., Weissleder, R. In vivo imaging of activated endothelium using an anti-VCAM-1 magnetooptical probe. Bioconjugate Chemistry, 16(3), May-June 2005, p 576-581.

Kelly, K., Allport, J. Tsourkas, A., et al. VCAM-1-mediated cell internalization allows in vivo imaging of activated endothelium. Circulation Research, 96(3), February 18 2005, p 327-336.


Tsourkas, A., Weissleder, R., Josephson, L. Surface functionalized nanoparticles using non-aqueous surface chemistry. Manuscript in preparation, 2004.

Bao, G., Tsourkas, A., Santangelo, P. Engineering nanostructured probes for sensitive intracellular gene detection. Mechanics and Chemistry of Biosystems, 1(1), 23-36.

Perez, J., Simeone, F., Tsourkas, A., Josephson, L., Weissleder, R. Peroxidase substrate nanosensors for MR imaging. Nano Letters, 4(1), 119-122, 2004.

Santangelo, P., Nix, B., Tsourkas, A., Bao, G. Dual FRET molecular beacons form RNA detection in living cells. Nucleic Acids Research, 32 (6), Art. No. e57, March 2004.

Tsourkas, A., Hofstetter, O., Hofstetter, H., Weissleder, R., Josephson, L. Magnetic relaxation switch immunosensors detect enantiomeric impurities. Angewandte Chemie International Edition, v 43, n 18, April 26 2004, p 2395-2399.

Tsourkas, A., Weissleder, R. Illuminating the dynamics of intracellular activity with ‘active’ molecular reporters. Mechanics and Chemistry of Biosystems, 1(2), 2004, P 133-145.

Tsourkas, A., Behlke, M., Xu, Y., Bao, G. Spectroscopic features of dual fluorescence/luminescence resonance energy-transfer molecular beacons. AnalyticalChemistry, 75(15), 3697-3703, 2003.

Tsourkas, A., Behlke, M., Rose, S., Bao, G. Hybridization kinetics and thermodynamics of molecular beacons. Nucleic Acids Research, 31(4), 1319-1330, 2003.

Tsourkas, A., Bao, G. Shedding light on health and disease using molecular beacons.Briefings in Functional Genomics and Proteomics, 1(4), 1-13, 2002.

Tsourkas, A., Behlke, M., Bao, G. Hybridization of 2’-O-methyl and 2’-deoxy molecular beacons to RNA and DNA targets. Nucleic Acids Research, 30(23), 5168-5174, 2002.

Tsourkas, A., Behlke, M., Bao, G. Structure-function relationships of shared-stem andconventional molecular beacons. Nucleic Acids Research, 30(19), 4208-4215, 2002.


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Lyle H. Ungar

Associate Professor of Computer and Information Science, Chemical and Biomolecular Engineering, and Electrical and Systems Engineering; Associate Professor of Operations and Information Management; Associate Professor of Genomics and Computational Biology.
Email: ungar at cis.upenn.edu
Personal Website

Research Interests:
Machine learning and data mining, of web pages, consumer purchases, gene expression data, and other large, structured data sets market-based methods for distributed scheduling and optimization of systems including human and computer agents, recommender systems and collaborative filtering (e.g. recommending movies to someone based on similarity of the movies they have liked to movies liked by others), statistical natural language processing, multiple automomous robots, computational biolology and computer go.

Selected Recent Publications:
A. I. Schein, A. Popescul, L.H. Ungar, and D.M. Pennock. CROC: A new evaluation criterion for recommender systems. Electronic Commerce Research, v 5, n 1, 2005, p 51-74.

R. H. Kwon, G. Anandalingam, and L.H. Ungar. Iterative Combinatorial Auctions with Bidder-Determined Combinations. Management Science 51(3), 407-418, March 2005.

P. Le Philip, Amit Bahl, and Lyle H. Ungar. Using Prior Knowledge to Improve Genetic Network Reconstruction from Microarray Data. In Silico Biology, 4(3),: 335-53, 2004.

E.C. Buehler, J.R. Sachs, K. Shao, A., Bagchi and L.H. Ungar. The CRASSS Plug-in for Integrating Annotation Data with Hierarchical Clustering Results. Bioinformatics, 20(17): 3266-9, November 22 2004.

Seth Kulick, Ann Bies, Mark Libeman, Mark Mandel, Ryan McDonald, Martha Palmer, Andrew Schein, and Lyle Ungar. Integrated Annotation for Biomedical Information Extraction. HLT/NAACL, Boston, May 2004.

Alexandrin Popescul, Lyle H. Ungar. Cluster-based Concept Invention for Statistical Relational Learning . In Proceedings of ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (KDD 2004).

Alexandrin Popescul, Lyle H. Ungar. Dynamic Feature Generation for Relational Learning . In Proceedings of Multi-Relational Data Mining Workshop (MRDM 2004) at KDD-04.

Andrew I. Schein, Alexandrin Popescul, Lyle H. Ungar, and David M. Pennock. CROC: A New Metric for Recommender System Evaluation. Electronic Commerce Research, 2004.

Andrew I. Schein, S. Ted Sandler, and Lyle H. Ungar. Bayesian Example Selection using BaBiES. The University of Pennsylvania Department of Computer and Information Science Technical Report No. MS-CIS-04-08, 2004.

Andrew I. Schein, Lyle H. Ungar.A-Optimality for Active Learning of Logistic Regression Classifiers. The University of Pennsylvania Department of Computer and Information Science Technical Report No. MS-CIS-04-07, 2004.

Lyle Ungar, Dean Foster, and Bob Stine. Streaming Feature Selection. Snowbird Learning Conference, 2004.

E.C. Buehler, L.H. Ungar. Maximum Entropy Methods for Biological Sequence Modeling. Journal of Computational Biology , 2003.

D. Pavlov, A. Popeschul, D.M. Pennock, L.H. Ungar. Mixtures of Conditional Maximum Entropy Models. Proceedings, 12th International Conference on Machine Learning, v 2, 2003, p 584-591.

S.T. Park A. Khrabrov, D.M. Pennock, et al. Static and Dynamic Analysis of the Internet Susceptibility to Faults and Attacks. IEEE INFOCOM, v 3, 2003, p 2144-2154.

G. Z. Grudic, L. H. Ungar. Learning Multi-agent Co-ordination using Secondary Reinforcers. 2003.

G. Z. Grudic, V. Kumar, and L. H. Ungar. Using Reinforcement Learning to Refine Autonomous Robot Controllers. 2003.

Seth Kulick, Mark Liberman, Martha Palmer, and Andrew Schein. Shallow Semantic Annotation of Biomedical Corpora for Information Extraction. Proceedings of the 2003 ISMB Special Interest Group Meeting on Text Mining (a.k.a. BioLink). June 27, 2003. Brisbane, Australia.

Roy Kwon and Lyle Ungar. A Combinatorial Auction-Based Method for Supply Chain Management. INFORMS, 2003.

R. Kwon, A. Anadalingam, and L. Ungar. An Approximation Algorithm for Winner Determination in Combinatorial Auctions. 2003.

A. Popescul, D. Foster, L. Ungar. Statistical Relational Learning at Penn. 2003.

Alexandrin Popescul, Lyle H. Ungar, Steve Lawrence, and David M. Pennock . Statistical Relational Learning for Document Mining . In Proceedings of IEEE International Conference on Data Mining (ICDM 2003).

Alexandrin Popescul, Lyle H. Ungar . Statistical Relational Learning for Link Prediction . Workshop on Learning Statistical Models from Relational Data at IJCAI 2003.

Alexandrin Popescul, Lyle H. Ungar. Structural Logistic Regression for Link Analysis. Workshop on Multi-Relational Data Mining at KDD 2003.

Andrew I. Schein, Lawrence K. Saul, and Lyle H. Ungar. A Generalized Linear Model for Principal Component Analysis of Binary Data. Proc. 9th International Workshop of AI & Statistics, 2003.

R. Aron, Markopoulos, P.M. and L.H. Ungar. Dual Pricing and Information Deficit in E-Commerce. WISE 2002.

D. Foster and L. Ungar A Propoal for Learning by Ontological Leaps, 2002.

Markopoulos, P.M. and Kephart, J.O. How Valuable are Shopbots? In Proc. First International Conference on Autonomous Agents and Multiagent Systems (AAMAS-02), Bologna, Italy 2002.

Markopoulos, P.M. and Ungar, L.H. 2002(extended version) Pricing Price Information in E-commerce

P.M. Markopoulos and L.H. Ungar. Book chapter "Shopbots and Pricebots in Electronic Service Markets" in "Game theory and decision theory in agent-based systems", Kluwer Academic Publishers, 2002.

Alexandrin Popescul, Lyle H. Ungar, Steve Lawrence, David M. Pennock . Towards Structural Logistic Regression: Combining Relational and Statistical Learning . Workshop on Multi-Relational Data Mining at KDD 2002.

A. I. Schein, A. Popescul, L. H. Ungar, and D. M. Pennock. Methods and Metrics for Cold-Start Recommendations.in Proceedings of the 25'th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval (SIGIR 2002), pp. 253-260.

Andrew I. Schein, Alexandrin Popescul and Lyle H. Ungar. PennAspect: A Two-Way Aspect Model Implementation .Pennsylvania Department of Computer and Information Science, Technical Report MS-CIS-01-25, 2002.


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Jan Van der Spiegel

Professor and Interim Department Chair, Electrical & Systems Engineering, UPS Term Chair, Director of the Center for Sensor Technologies
Email: jan at ee.upenn.edu
Personal Website

Research Interests:
Vision Sensors: The goal of this program is the study and development of vision systems that are able to deal with the complex sensory processing task. The approach followed is to a large extent inspired by the biological system and makes use of a hierarchy of processing stages. Among the system being studied is a motion perception and visual tracking chip which acquires a two-dimensional image and determines the direction of motion. The chip makes use of a spatially variant layout and of an arbitration scheme between smooth pursuit and acquisition. Another vision sensor that is currently being explored is a polarization difference imager (with Prof. N. Engheta and E. Pugh). The goal is to design and fabricate an integrated microelectronics polarization-difference camera, consisting of a polarization analyzer on top of a CMOS imager. The imager produces, on a per-pixel basis, the weighted sum and difference signals.

Acoustic-Phonetic Feature Extraction for Automatic Speech: The goal of this project is to integrate acoustic-phonetic knowledge into the current state-of-the-art speech recognition systems. We use auditory-based front-end preprocessing that incorporates many of the human-like effects such as critical band filtering, short-term adaptation, forward masking, nonlinearities, etc. The output of such preprocessing block enters the feature extraction system that extracts the acoustic-phonetic features while minimizing error propagation and information loss. New algorithms are designed and implemented for feature extraction and phoneme recognition using both hard- and soft- decision methodologies.

Mixed mode Integrated Circuits for Data Acquisition Systems: We are currently exploring different architectures and algorithms to realize high performance analog-to-digital converters. One project deals background calibration schemes to correct for any residual non-idealities in pipe-lined analog-to-digital converters.

Selected Recent Publications:
Jie Yuan; Farhat, N.; Van der Spiegel, J. GBOPCAD: a synthesis tool for high-performance gain-boosted opamp design. IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications, v 52, n 8, Aug. 2005, p 1535-44.

A. Mouchtaris, J. Van der Spiegel and Paul Mueller. A Spectral Conversion Approach to The Iterative Wiener Filter for Speech Enhancement. Proc. of IEEE Int. Conf. on Multimedia and Expo (ICME2004), Taipei, Taiwan, June 27-30, 2004.

A. Mouchtaris, J. Van der Spiegel and Paul Mueller. Non-Parallel Training For Voice Conversion By Maximum Likelihood Constrained Adaptation. AProc. IEEE Int. Conference on Acoustics, Speech and Signal Processing (ICASSP04), Montreal, May 17-21, 2004.

Jan Van der Spiegel and M. Nishimura. [Plenary talk]. Biologically Inspired Vision Sensor for the Detection of Higher-Level Image Features. Proc. of the IEEE Conf. Electron Devices and Solid-State Circuits, pp. 11-16, Hong Kong, Dec. 16-18, 2003.

S. Sonkusale, J. Van der Spiegel. Mixed-signal calibration of pipelined analog-digital converters. Proceedings. IEEE International SOC [Systems-on-Chip] Conference, 17-20 Sept. 2003.

Chao Xu, Winslow Sargeant, K. Laker and J. Van der Spiegel.Fully Integrated CMOS Phase Locked Loop with 30MHz to 2GHz Locking Range and +/-35ps Jitter. Journal of Analog Integrated Circuits and Signal Processing, July-August 2003, Volume 36, Issue 1-2. pp. 91-97.

A. M. Ali, J. Van der Spiegel and P. Mueller. Auditory-based speech processing based on the average localized synchrony detection", accepted for publication in IEEE Trans. on July Processing, 2002.

Chao Xu, W. Sargeant, K. Laker and J. Van der Spiegel.An Extended Frequency Range CMOS Voltage-Controlled Oscillator. 9th IEEE International Conference on Electronics, Circuits and Systems Conf - ICECS 2002, Proc. Volume: 2 , pp. 15-18 , Sept. 2002.

A. M. Ali, J. Van der Spiegel and P. Mueller. Robust Auditory-Based Speech Processing Using the Average Localized Synchrony Detection. IEEE Trans. on Speech and Audio Processing, Vol. 10, pp. 279-292, July 2002.

R. Powell, H. Anderson, J. Van der Spiegel and D. Pope.Using web-based technology in laboratory instruction to reduce costs. Computer Applications In Engineering Education, Vol. 10, No. 4, pp. 204-214, 2002.

Sameer Sonkusale and Jan Van der Spiegel. A Low Distortion MOS Sampling Circuit. IEEE Int. Symposium on Circuits and Systems - ISCAS, May 2002, Vol. 5, pp. 585 588.

J. Van der Spiegel, R. Etienne-Cummings and M. Nishimura. Biologically Inspired Vision Sensors. Proc. 23rd Int. Conf. On Microelectronics MIEL02), pp. 125-131, Vol.1 , Nis, Yugoslavia, May 2002.

Chao Xu, F. Barber, W. Sargeant, K. Laker and J. Van der Spiegel. Analysis of Clock Buffer Phase Noise. IEEE Int. Symposium on Circuits and Systems - ISCAS, May 2002, Vol. 5, pp. 657 -660.


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Santosh S. Venkatesh

Associate Professor of Electrical and Systems Engineering
Email: venkates at ee.upenn.edu
Personal Website

Research Interests:
Pattern recognition: Complexity of learning from mixtures of labeled and unlabeled examples; finite sample effects on classification performance. The goal of these projects is to develop and analyze algorithms in finite, mixed, pattern classification environments. Computational learning: Dynamics of learning algorithms; sample complexities of learning. The goal of these projects is to track analytically track the progress of learning algorithms in neural network and other applications to come up with universal model selection principles. Information theory: Is fraud detectable? The goal of this project is to analyze models of fraud to determine under what conditions fraudulent data provided by a malicious (or simply sleazy) adversary can be detected. Randomized learning algorithms: Finite memory storage; learning in neural network and other environments with finite resources. The goal of these projects is to design and analyze randomized algorithms which optimally utilize finite memory in a variety of contexts such as neural networks. Communication theory: Redundant transmissions over constrained channels. This project deals with quantifying how redundancy can be exploited maximally in a multi-user, multi-path, communication environment.

Selected Recent Publications:
J-H. Kim and S. S. Venkatesh. Learning Binary Threshold Functions via Iterative Majority Rule. (to appear soon)

S. S. Kunniyur and S. S. Venkatesh. Threshold Functions, Node Isolation, and Emergent Lacunae in Sensor Networks. IEEE Transactions on Information Theory, submitted.

S. S. Venkatesh. Combinatorial Threshold Functions for the Number of Users that Can Be Supported in a Direct Sequence Spread Spectrum System. (to appear soon)

J.H. Song, S.S. Venkatesh, E.A. Conant, et al. Comparative Analysis of Logistic Regression and Artificial Neural Network for Computer-Aided Diagnosis of Breast Masses. Academic Radiology, 12(4), April 2005, p 487-495.

S. S. Venkatesh. Connectivity of Metric Random Graphs, submitted 2004.

S. S. Kunniyur and S. S. Venkatesh. On the Growth of Lacunae in Sensor Networks. 2004 International Symposium on Information Theory, Chicago, Illinois, June 27-July 2, 2004.

S. S. Kunniyur and S. S. Venkatesh. On the Breakdown of Survivor Connectivity in Sensory Networks. 2004 International Symposium on Information Theory, Chicago, Illinois, June 27-July 2, 2004.

S. S. Kunniyur and S. S. Venkatesh. Network Devolution and the Growth of Sensory Lacunae in Sensor Networks. WiOpt'04: Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks, University of Cambridge, UK, March 2004.

C. Gunter, S. Khanna, K. Tan, and S. S. Venkatesh. DoS Protection for Reliably Authenticated Broadcast. 11th Annual Network and Distributed System Security Symposium , San Diego, California, February 2004.


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Vaclav Vitek

Professor of Materials Science and Engineering; Professor of Mechanical Engineering and Applied Mechanics
Email: vitek at lrsm.upenn.edu
Personal Website

Research Interests:
Atomic level behavior of dislocations in transition metals and intermetallic compounds:
Dislocation core structures control the main characteristics of the plastic flow in many crystalline materials, ranging from bcc transition metals, such as molybdenum and tantalum, to complex intermetallics, for example transition metals silicides. Common signatures of core effects are ‘strange’ slip geometries, strong and unusual dependence of flow stress on crystal orientation and temperature and dependence of slip on components of stress other than the shear stress in the slip direction. In this research we seek the relationship between the atomic configuration of dislocation cores and macroscopic plastic flow via computer simulation of the dislocation motion under variously applied stresses. Using the results of atomistic studies we develop physically based constitutive models for macroscopic analyses of the plastic flow. Such multiscale modeling links the atomic level properties of dislocations with macroscopic plastic behavior and builds a bridge between basic physics and properties of engineering materials.

Interfaces and grain boundaries:
Many outstanding problems in materials science are closely linked with interfacial phenomena and the key to a fundamental understanding of the role of interfaces is their atomic structure. Using computer simulation, we are investigating the atomic and electronic structure as well as properties such as interfacial cohesion, diffusion, formation of unusual interfacial phases, interaction with dislocations and interfacial chemistry related to segregation. The calculations range from ab initio DFT based electronic structure calculations, real space tight-binding methods, to state of the art empirical approaches allowing modeling of very large systems. Examples are studies of Nb/sapphire interfaces and interfaces encountered in the lamellar TiAl alloys. The modeling is synergistically linked with the high resolution electron microscopy and other experimental studies.

Descriptions of atomic interactions for atomistic computer modeling:
The necessary precursor of any atomistic studies is a physically based description of atomic interactions that reflects correctly the principal aspects of bonding. We are advancing such descriptions on several levels, ranging from many-body central-force potentials to bond-order potentials that are capable to reflect correctly the mixture of metallic and covalent bonding encountered in many complex structural and functional materials. All these methods are semiempirical but the principal input into these schemes is from ab initio DFT based calculations, which are the present state of the art theoretical tool for study of bonding in materials.

Selected Recent Publications:
Cawkwell, MJ; Nguyen-Manh, D; Woodward, C; Pettifor, DG; Vitek, V. Origin of brittle cleavage in iridium. SCIENCE, 309 (5737): 1059-1062 AUG 12 2005.

V. Vitek. Dislocation Cores and Unconventional Properties of Plastic Behavior. Handbook of Materials Modeling Vol. I: Methods and Models, edited by S. Yip, Springer, pp 2883-2896, 2005.

M. Sob, J. Pokluda, M. Cerny, et al. Theoretical strength of metals and intermetallics from first principles. Materials Science Forum 482: 33-38 2005.

R. Groger and V. Vitek. Breakdown of the Schmid law in bcc molybdenum related to the effect of shear stress perpendicular to the slip direction. Materials Science Forum 482: 123-126 2005.

M. Sob, M. Friak, D. Legut, J. Fiala, and V. Vitek. The role of ab initio electronic structure calculations in studies of the strength of materials. Mat. Sci. Eng. A 387-389, 148-157, 2004.

V. Vitek, M. Mrovec, R. Groger, J.L. Bassani, V. Racherla, and L. Yin. Effects of non-glid stresses on the plastic flow of single and polycrystals of molybdenum. Mat. Sci. Eng. A 387-389, 138-142, 2004.

M. Mrovec, D. Nguyen-Manh, D. G. Pettifor and V. Vitek. Bond-order potential for molybdenum. Application to dislocation behaviour, Phys. Rev. B 69, 094115, 2004.

V. Vitek. Core structure of dislocations in body-centred cubic metals: relation to symmetry and interatomic bonding. Philos. Mag. 84, 415-428, 2004.

V. Vitek, M. Mrovec and J. L. Bassani. Influence of non-glide stresses on plastic flow: from atomistic to continuum modelling. Mat. Sci. Eng. A 365, 31, 2004.

P.N.B. Anongba and V. Vitek. Significance of the deviations of the crack front into the plane perpendicular to the crack propagation direction, Int. J. Fracture 124, 1-15, 2003.

M. J. Cawkwell, Duc Nguyen-Manh, V. Vitek and D. G. Pettifor. A Combined Ab Initio and Bond-Order Potentials Study of Cohesion in Iridium, in Multiscale Phenomena in Materials--Experiments and Modeling Related to Mechanical Behavior, edited by H. M. Zbib, D. H. Lassila, L. E. Levine, K. J. Hemker. MRS Symposium Proceedings, Vol. 779, p. W5.5.1, 2003.

Y. Chen. D. P. Pope and V. Vitek. Dislocation/Twin/Interface Interactions during Deformation of PST TiAl Single Crystals, an AFM Study, in Defect Properties and Related Phenomena in Intermetallic Alloys, edited by E. P. George, H. Inui, M. J. Mills, G. Eggeler. MRS Symposium Proceedings, Vol. 753, p. BB3.10.1, 2003.

M. Friak, M. Sob and V. Vitek. Ab initio calculation of tensile strength of iron. Philos. Mag. 83, 3529-3537, 2003.

M. Friak, M. Sob and V. Vitek. An ab initio study of the ideal tensile strength and mechanical stability of transition-metal disilicides. Phys. Rev. B 68, 184101-10, 2003.

M. Mrovec, T. Ochs, C. Elsässer, V. Vitek, D. Nguyen-Manh and D. G. Pettifor. Never ending saga of a simple boundary. Z. Metallkunde, 94, 244-249, 2003.

D. Nguyen-Manh, D. G. Pettifor, D. J. H. Cockayne, M. Mrovec, S. Znam. Environmentally Dependent Bond-Order Potentials: New Developments and Applications. Bulletin of Materials Science (India) 26, 43-51, 2003.

M. Nomura and V. Vitek. An atomistic study of interfacial diffusion in lamellar TiAl alloys. Interface Science 11, 99-109, 2003.

R. Porizek, S. Znam, D. Nguyen-Manh, V. Vitek and D. G. Pettifor. Atomistic studies of dislocation glide in -TiAl, in Defect Properties and Related Phenomena in Intermetallic Alloys, edited by E. P. George, H. Inui, M. J. Mills, G. Eggeler. MRS Symposium Proceedings, Vol. 753, p. BB4.3.1-6, 2003.

S. Znam, D. Nguyen-Manh, D. G. Pettifor and V. Vitek. Atomistic Modelling of TiAl. Bond-order Potentials with Environmental Dependence. Philos. Mag. 83, 415, 2003.

D. J. Bacon and V. Vitek. Atomic-scale modelling of dislocations and related properties in the h.c.p. metals. Metallugical and Materials Transactions A 33, 721, 2002.

M. S. Duesbery, V. Vitek and J. Cserti. Non-Schmid Plastic Behaviour in BCC Metals and Alloys. Understanding Materials: A Festschrift for Sir Peter Hirsch, edited by C. J. Humphreys, The Institute of Materials, London, p. 165, 2002.

J. A. Moriarty, V. Vitek, V. V. Bulatov and S. Yip. Atomistic Simulations of Dislocations and Defects. Journal of Computer-Aided Materials Design 9, 99-132, 2002.

V. Paidar and V. Vitek. Stacking Fault-Type Interfaces and their Role in Deformation, in Intermetallic Compouds: Principles and Practice, Vol. 3, edited by J. H. Westbrook and R. L. Fleisher, John Wiley, New York, p. 437-467, 2002.

D. G. Pettifor, I. I. Oleinik, D. Nguyen-Manh and V. Vitek. Bond-order potentials: bridging the electronic and atomistic modelling hierirchies. Computational Materials Science 23, 33, 2002.


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John M. Vohs

Chairman and Carl V. S. Patterson Professor of Chemical and Biomolecular Engineering
Email: vohs at seas.upenn.edu
Personal Website

Research Interests:
Surface science studies of model supported vanadia catalysts, fundamental studies of automotive emissions control catalysts, conducting polymer-metal interfaces, surface chemistry of metalorganic chemical vapor deposition (MOCVD) processes. The central theme of understanding and controlling phenomena characteristic of surfaces, interfaces, and thin films. The properties of surfaces and interfaces are fundamental to a variety of technologies ranging from catalysis to electronic materials. In many of these areas it is now evident that a molecular-level understanding of surface and interfacial phenomena will be required for significant advances to be made. Over the past decade, developments in both experimental techniques capable of probing the chemical and physical properties of surfaces and in the molecular theories which describe surface properties have in many ways laid the foundation necessary for these detailed molecular descriptions to be realized. One of the primary goals of the research program is to expand the realm of surface science beyond that of metals to include a spectrum of technologically important materials. Research activities are currently focusing on characterizing molecular processes which occur on three classes of materials: metal oxides, semiconductors, and polymers.

Chemistry of Metal Oxide Surfaces: Metal oxides are an important class of materials used as catalysts for a variety of reactions including selective oxidations, cracking and alcohol synthesis. Metal oxides are also used as high surface area supports for transition metal catalysts, gas sensors, semiconductor devices, and opto-electronic devices. In all of these applications the surface chemical and electronic properties of the oxide play a central role. In light of this importance, it is surprising that relative to other materials (e.g. metals) there have been so few fundamental investigations of their surface chemical properties. Indeed, our research group is one of the few in the world that has a major effort in this area. Our research is currently concentrated in two areas: the adsorption and reaction of organic molecules on oxides, and the interaction of metals with oxide surfaces.

Surface Chemistry of Electronic Materials Processing: Surface chemistry plays an important role in many aspects of the production of electronic materials and their fabrication into useful devices. For example pattern generation, the formation of dielectric layers and interconnects, and dopant incorporation are all steps in the manufacturing of a microelectronic device in which surface reactions take place. The production of thin film electronic materials using molecular beam epitaxy and chemical vapor deposition are also good examples of processes in which surface chemistry is important. The goal of our research efforts in this area is to provide a fundamental description of the reactivity of semiconductor surfaces as well as an understanding of the mechanisms of surface reactions relevant to several of the processing steps listed above. The primary area of the research group is currently concentrating its efforts is on elucidating the mechanisms of surface reactions involved in the production of compound semiconductor thin films using metalorganic chemical vapor deposition (MOCVD) and metalorganic molecular beam epitaxy (MOMBE).

Polymer Surfaces and Interfaces: The surface and interfacial properties of polymers have gained increased importance in coatings/ packaging technologies for microelectronics applications as well as potential applications in nanoscale/molecular electronics and chemical sensors. Beyond the study of surface properties, it is fundamentally important to understand the chemistry of adhesion in ultrathin metal-polymer, semiconductor-polymer, and polymer-polymer interfaces. A recent advance in the characterization of the vibrational structure of surfaces using low energy electrons promises for the first time to allow the chemical structure and reactivity of polymer surfaces to be studied in a quantitative way. Our studies of polymer surfaces will make use of well-characterized model systems and state of the art surface vibrational spectroscopy to study a variety of aspects of polymer surface chemistry. Initial studies will focus on conducting polymers such as polyaniline and polypyrrole which have potential uses as chemical sensors.

Selected Recent Publications:
Ahn, KY; He, HP; Vohs, JM; Gorte, RJ. Enhanced thermal stability of SOFC anodes made with CeO2-ZrO2 solutions. ELECTROCHEMICAL AND SOLID STATE LETTERS, 8 (8): A414-A417 2005.

Y.Y. Huang, J.M. Vohs, and R.J. Gorte. Characterization of LSM-YSZ Composites Prepared by Impregnation Methods. Journal of the Electrochemical Society 152 (7): 1347-1353 2005.

H. He, R.J. Gorte, J.M., and J.M. Vohs. Highly Sulfur Tolerant Cu-ceria anodes for SOFCs. Electrochemical and Solid-State Letters, v 8, n 6, 2005, p A279-A280.

H. He, J.M. Vohs, and R.J. Gorte. Carbonaceous Deposits in Direct Utilization Hydrocarbon SOFC Anode. Journal of Power Sources, v 144, n 1, June 1 2005, p 135-140.

O. Costa-Nunes, R.J. Gorte, and J.M. Vohs. High Mobility of Ceria Films on Zirconia at Moderate Temperatures. Journal of Materials Chemistry 15 (15): 1520-1522 2005.

O. Costa-Nunes, R.J. Gorte, and J.M. Vohs. Comparison of the Performance of Cu-CeO2-YSZ and Ni-YSZ Composite SOFC Anodes with H2, CO, and syngas. Journal of Power Sources, v 141, n 2, March 1 2005, pp 241-249.

S.I. Lee, K. Ahn, J.M. Vohs, and R.J. Gorte. Cu-Co Bimetallic Anodes for Direct Utilization of Methane in SOFCs. Electrochemical and Solid State Letters, v 8, n 1, 2005 p A48-A51.

T. Feng and J.M. Vohs. Temperature-programmed Desorption Study of the Selective Oxidation of Alcohols on Silica-Supported Vanadium Oxide. Journal of Physical Chemistry B 109 (6): 2120-2127, February 17 2005.

M. Enever, S. Linic, K. Uffalussy, J.M. Vohs, and M.A. Barteau. Synthesis, Structure and Reactions of Stable Oxametallacycles from Styrene Oxide on Ag(111). J. Phys. Chem. B, 109(6): 2227-2233 February 17 2005.

T. Feng and J.M. Vohs. A TPD Study of the Oxidation of Alcohols on Silica-Supported Vanadium Oxide Catalysts. J. Phys. Chem. B, in press.

R.J. Gorte, J.M. Vohs, and S McIntosh. Recent Developments on Anodes for Direct Fuel Utilization in SOFCs. Solid State Ionics 175 (1-4): 1-6 Sp. Iss. SI November 30 2004.

C. Lu, S. An, W. L. Worrell, J. M. Vohs, and R. J. Gorte. Development of Intermediate-Temperature Solid Oxide Fuel Cells for Direct Utilization of Hydrocarbon Fuels. Solid State Ionics, 175 (1-4): 47-50 Sp. Iss. SI November 30 2004.

S. An, C. Lu, W. L. Worrell, R. J. Gorte, and J. M. Vohs. Characterization of Cu-CeO2 Direct Hydrocarbon Anodes in a Solid Oxide Fuel Cell with Lanthanum Gallate Electrolyte. Solid State Ionics, 175(1-4)” 135-138 Sp. Iss. SI November 30 2004.

H. He, Y. Huang, J. M. Vohs, and R. J. Gorte. Characterization of YSZ-YST Composites for SOFC Anodes. Solid State Ionics, v 175, n 1-4, November 30 1004, p 171-176.

Y. Huang, K. Ahn, J.M. Vohs, and R.J. Gorte. Characterization of Sr-Doped LaCoO3-YSZ Composites Prepared by Impregnation Methods. J. Electrochem. Soc., v 151, n 10, 2004, p A1592-A1597.

S.-I. Lee, J. M. Vohs, and R. J. Gorte. A Study of SOFC Anodes Based on Cu-Ni and Cu-Co Bimetallics. J. Electrochem. Soc., 151(9): A1319-A1323 2004.

A. Atkinson, S. Barnett, R.J. Gorte, J.T.S. Irvine, A.J. MeEvoy, M.B. Mogensen, S. Singhal, and J.M. Vohs. Advanced Anodes for High Temperature Fuel Cells. Nature Materials, 3, 2004, 17.

T. Feng and J.M. Vohs. Mechanism of -Hydrogen Abstraction from Adsorbed Alkoxides on Supported Metal Oxide Catalysts. J. Phys. Chem. B, 108, 2004, 5647.

T. Feng and J.M. Vohs. A TPD Study of the Partial Oxidation of Methanol to Formaldehyde on CeO2-Supported Vanadium Oxide. J. Catal. 221, 2004, 619.

H. He, Y. Huang, J. Regal, M. Boaro, J.M. Vohs and R. J. Gorte.Low-Temperature Method for Fabrication of Oxide Composites. J. Am. Ceramics Soc., 87, 2004, 331.

Y. Huang, J.M. Vohs, and R.J. Gorte. Fabrication of Sr-doped LaFeO3YSZ Composite Cathodes. J. Electrochem. Soc., 151, 2004, A646.

V.V. Krishnan, S. McIntosh, R.J. Gorte, and J.M. Vohs. Measurement of Electrode Overpotentials for Direct Hydrocarbon Conversion Fuel Cells. Solid State Ionics, 166, 2004, 191.

S. McIntosh, S. B. Adler, J. M. Vohs, and R. J. Gorte.Effect of Polarization on and Implications for Characterization of LSM-YSZ Composite Cathodes. Electrochem. Solid State Lett., 7, 2004, A111.

S. McIntosh, H. He, S.-I. Lee, O. Costa-Nunes, V. V. Krishnan, J. M. Vohs and R. J. Gorte. An Examination of Carbonaceous Deposits in Direct-Utilization SOFC Anodes. J. Electrochem. Soc., 151, 2004, A604.

M. Boaro, J.M. Vohs, and R.J. Gorte. Synthesis of Highly Porous YSZ by Tape-Casting Methods. J. Am. Ceram. Soc., 86, 2003, 395.

O. Costas-Nunes, J.M. Vohs, and R.J. Gorte. A Study of Direct-Oxidation SOFC with n-Butane at Higher Fuel Utilization. J. Electrochem. Soc., 150, 2003, A858.

T. Feng, G.A. Barker and J.M. Vohs. Determination of Active Site Densities on Supported Vanadia Catalysts Using Gravimetric Measurement of Methanol Uptake. Langmuir, 19, 2003, 1268.

R.M. Ferrizz, R.J. Gorte, and J.M. Vohs. Determining the Ce2O2S-CeOx Phase Boundary for Conditions Relevant to Adsorption and Catalysis. Applied Catalysis B: Env., 43, 2003, 273.

I. Fishbein, I.S. Alferiev, G.S. Wong, J.M. Vohs, J.M. Connolloy, R.I. Wilensky, R.J. Levy. An Ultra-Thin Polymer Coating for the Tethering of Adenoviral Vector to the Surface of Coronary Stents. Molecular Therapy, 7, 2003, 853.

R.J. Gorte and J.M. Vohs. Novel SOFC Anodes for the Direct Electrochemical Oxidation of Hydrocarbons. J. Catal., 216, 2003, 477.

H. He, J.M. Vohs, and R.J. Gorte. Effect of Synthesis Conditions on the Performance of Cu-CeO2-YSZ Anodes in SOFCs. J. Electrochem. Soc. 150, 2003, A1470.

S.-I. Lee, S. McIntosh, J. M. Vohs, and R. J. Gorte. Copper-Plated Stainless Steel for Bipolar Plates in Direct-Oxidation SOFC. Electrochemical Society Proceedings, vol. 2003-07, 865-871.

C. Lu, W.L. Worrell, R.J. Gorte, J.M. Vohs. SOFCs for Direct Oxidation of Hydrocarbon Fuels with Samaria-Doped Ceria Electrolyte. J. Electrochem. Soc., 150, 2003, A354.

C. Lu, W. L. Worrell, J. M. Vohs, and R. J. Gorte. A Comparison of Cu-Ceria-SDC and Au-Ceria-SDC Composites for SOFC Anodes. Electrochemical Society Proceedings, vol. 2003-07, 773-780, 2003.

C. Lu, W. L. Worrell, J. M. Vohs, and R. J. Gorte. A Comparison of Cu-Ceria-SDC and Au-Ceria-SDC Composites for SOFC Anodes. J. Electrochem. Soc., 150, 2003, A1357.

S. McIntosh, J.M. Vohs, and R.J. Gorte. Effect of Precious-Metal Dopants on SOFC Anodes for Direct Utilization of Hydrocarbons. Electrochem. Solid State Lett. 6, 2003, A240.

S. McIntosh, J.M. Vohs, and R.J. Gorte. Impedance Spectroscopy for the Characterization of Cu-Ceria-YSZ Anodes for SOFCs. J. Electrochem. Soc., 150, 2003, A1305.

S. McIntosh, J.M. Vohs, and R.J. Gorte. Role of Hydrocarbon Deposits in the Enhanced Performance of Direct-Oxidation SOFCs. J. Electrochem. Soc., 150, 2003, A470.

E. E. Paz, C. Wang, P. Palanisamy, R. J. Gorte, and J. M. Vohs. Direct Oxidation as a Market Enabler for Solid-Oxide Fuel Cells. Electrochemical Society Proceedings, vol. 2003-07, 787-792.

D.P. Pursell, M.-L. Bocquet, J.M. Vohs, and H.-L. Dai. Adsorption Structure, Energetics, and Thermal Reactions of Vinyl Chloride on Ag(111). Surface Science, 522, 2003, 90.

J.M. Vohs. Oxygenated Hydrocarbons on Metal Surfaces. in Landolt-Bornstein, Numerical Data and Fundamental Relationships in Science and Technology, vol 42, subvolume A, Physics of Covered Solid Surfaces - Adsorbed Layers on Surface, H.P. Bonzel, ed., Springer, 2003, pp. 426-440.

J.M. Vohs, T. Feng, and G.S. Wong.Comparison of the Reactivity of High-Surface Area, Monolayer Vanadia/Ceria Catalysts with Vanadia/CeO2(111) Model Systems.Catalysis Today, 85, 2003, 303.

G.S. Wong, M.R. Concepcion and J.M. Vohs. Reactivity of Monolayer V2O5 Films on TiO2(110) Produced via the Oxidation of Vapor-Deposited Vanadium. Surface Science, 526, 2003, 211.

G.M. Crosbie, E.P. Murray, D.R. Bauer, H. Kim, S. Park, J.M. Vohs, and R.J. Gorte. Solid Oxide Fuel Cells for Direct Oxidation of Liquid Hydrocarbon Fuels in Automotive Auxiliary Power Units: Sulfur Tolerance and Operation on Gasoline. SAE paper 2002-01-0410, 2002.

T. Feng and J.M. Vohs. TPD-TGA and Calorimetric Study of the Partial Oxidation of Methanol on TiO2-Supported Vanadium Oxide. J. Catal., 208, 2002, 301.

R.M. Ferrizz, R.J. Gorte, J.M. Vohs. PD and XPS Investigation of the Interaction of SO2 with Model Ceria Catalysts. Cat. Lett., 82, 2002, 123.

R.J. Gorte, H. Kim, and J.M. Vohs. Novel SOFC Anodes for the Direct Electrochemical Oxidation of Hydrocarbons. J. Power Sources, 106, 2002, 10.

H. Kim, C. DaRosa, M. Boaro, J.M. Vohs, and R.J. Gorte. Fabrication of Highly Porous YSZ by Acid Leaching Ni from a Ni-YSZ Cermet. J. Am. Ceramics Soc., 85, 2002, 1473.

H. Kim, C. Lu, W.L. Worrell, J.M. Vohs, and R.J. Gorte.Cu-Ni Cermet Anodes for Direct Oxidation of Methane in Solid-Oxide Fuel Cells. J. Electrochem. Soc. 149, 2002, A247.

C. Lu, W.L. Worrell, H. Kim, R.J. Gorte, and J.M. Vohs. Characterization of a Cu0.8Ni0.2-CeO2-YSZ Anode-Composite for the Direct Oxidation of Dry Methane. Proceedings of the Electrochemical Society, vol. 2002-5, pp.88-96.

C. Lu, W.L. Worrell, J.M. Vohs, and R.J. Gorte. Fabrication of SDC, Electrolyte-Supported ITSOFCs for Direct Oxidation of Hydrocarbon Fuels. Proceedings of the Electrochemical Society, vol. 2002-5, pp. 72-78.

C. Lu, W.L. Worrell, C. Wang, S. Park, H. Kim, J.M. Vohs, R.J. Gorte. Development of Solid Oxide Fuel Cells for the Direct Oxidation of Hydrocarbon Fuels. Solid State Ionics, 152, 2002, 393.

T. Luo, J.M. Vohs, and R.J. Gorte. An Examination of Sulfur Poisoning on Pd/Ceria Catalysts. J. Catal., 210, 2002, 397.

S. McIntosh, J.M. Vohs, and R.J. Gorte. An Examination of Rare-Earth Additives on Performance of Cu-YSZ Cermet Anodes.Electrochem. Acta, 47, 2002, 3815.

G.S. Wong, M.R. Concepcion, and J.M. Vohs. Oxidation of Methanol to Formaldehyde on Vanadia Films Supported on CeO2(111). J. Phys. Chem. B, 106, 2002, 6451.

G.S. Wong and J.M. Vohs. An XPS Study of the Growth and Electronic Structure of Vanadia Films on CeO2(111). Surface Science, 498, 2002, 266.


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Vukan R. Vuchic

UPS Foundation Professor of Transportation Engineering; Professor of Electrical and Systems Engineering
Email: vuchic at seas.upenn.edu
Personal Website

Research Interests:
Urban transportation systems; transit and highway network designs; urban transportation policies and their impact on urban economy, social, and environmental aspects; increasing the livability of metropolitan areas; balanced transportation; comparative analysis of policies and practices affecting transportation in the United States and its peer countries.

Selected Recent Publications:
Lee, Y.J., Vuchic, Vukan R. Transit Network Design with Variable Demand. Journal of Transportation Engineering, v 131, n 1, January 2005, p 1-10.

Vuchic, Vukan R. Urban Transit: Operations, Planning and Economics. John Wiley & Sons, 2005.

Vuchic, Vukan R. Ensuring Sustainability through Mass Transit. Urban Public Transportation Systems: Ensuring Sustainability Through Mass Transit – Proceedings of the Second International Conference, 2004, p 483-489.

Shin, Y.E., Vuchic, Vukan, R., Sin, P.S., and Eun, C.G. Planning for the First Light Rail Transit System in Korea: Jeonju Light Rail Transit Project. Transportation Research Record, n 1872, 2004, p 46-55.

Vuchic, Vukan R. Livable Cities - Will Transportation Professionals Answer the Challenge? Transportation Research News, Nov-. 2003, pp. 22-26.

Vuchic, Vukan R. Urban Public Transportation System. in Section 6.40, Transportation Engineering and Planning of UNESCO Encyclopedia of Life Support Systems -EOLSS, edited by T.J.Kim; EOLSS Publishers, Oxford, UK, 2003; 24 pages. [http://www.eolss.net]

Vuchic, Vukan R. Medium Capacity Guided Transit Systems. Proceedings of the Workshop on Medium-Capacity Transit, Korea Railroad Research Institute, Korea, 25-26 Apr. 2002, pp. 45-72.

Vuchic, Vukan R. Bus Semirapid Transit Mode Development and Evaluation. Journal of Public Transportation, Vol. 5, No. 2, 2002, pp. 71-95.

Vuchic, Vukan R. & Jeffrey M. Casello. Evaluation of Maglev Technology and Its Comparison with High-Speed Rail. Transportation Quarterly, Vol. 56, Spring 2002, pp. 33-49.

Vuchic, Vukan R. & Jeffrey M. Casello. Washington Metro: Planning for Growth. Urban Transport International, No. 40, Mar/Apr 2002, pp. 26-30.


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Stephanie Weirich

Assistant Professor of Computer and Information Science
Email: sweirich at cis.upenn.edu
Personal Website

Research Interests:
My research interests lie in extensions of strongly-typed programming languages to support greater prescriptive and descriptive power. In doing so, I hope to improve the process of building reliable, secure, and efficient software. Why concentrate on typed programming languages? There are a number of formalisms for program verification, but type systems have been one of the most practical. The types of a programming language are an abstraction of the execution of a program written in that language, and so may describe its properties. Therefore, the type system may verify that the program is used consistently and correctly. This facility leads to more secure software because security flaws in software have often resulted from malicious users deliberately supplying arguments that do not satisfy the preconditions of an operation. For example, an intruder may supply a string argument that leads to buffer overflow in order to compromise a software system. The level of assurance about the reliability and security of a program is determined by the precision that we specify its operation. If that specification is too precise, it may restrict what programs may be verified and render the system impractical. Therefore type systems incorporate mechanisms for type abstraction in order to allow user control of the precision of the specification. Likewise, we may need to break the provided abstractions in order to verify certain operations through the use of run-time type checks. For example, if the type of an array statically records its length, but that length has been held abstract, we must check that an array access is within bounds at run time. Therefore, it is important that an expressive type system includes a facility to analyze types at run time. There is another reason to incorporate mechanisms for run-time type analysis: Modern systems are increasingly becoming more adaptive and evolutionary. These frameworks depend crucially on reflection facilities, the ability of programs to dynamically observe objects and adapt to them. Many necessary operations can be specified only in terms of abstractions of these objects (i.e. their types). For example, functions such as garbage-collector tracers, data marshalers, and structural-equality functions operate over the structure of data instead of its value. Therefore, it is important provide a firm basis for the programming languages that will be used to implement these new systems.

Selected Recent Publications:
Dimitrios Vytiniotis, Stephanie Weirich, and Simon Peyton Jones. Boxy type inference for higher-rank types and impredicativity. Submitted for publication, April 2005.

Daniel S. Dantas, David Walker, Geoffrey Washburn, and Stephanie Weirich. PolyAML: A polymorphic aspect-oriented functional programmming language. In ACM SIGPLAN International Conference on Functional Programming (ICFP), Tallinn, Estonia, September 2005. To appear. Online version is draft of April 2005.

Brian E. Aydemir, Aaron Bohannon, Matthew Fairbairn, J. Nathan Foster, Benjamin C. Pierce, Peter Sewell, Dimitrios Vytiniotis, Geoffrey Washburn, Stephanie Weirich, and Steve Zdancewic. Mechanized metatheory for the masses: The POPLmark challenge. In The 18th International Conference on Theorem Proving in Higher Order Logics, Oxford, UK, August 2005.

Geoffrey Washburn and Stephanie Weirich. Generalizing parametricity using information flow. In IEEE Symposium on Logic in Computer Science (LICS), Chicago, IL, USA, June 2005.

Dimtrios Vytiniotis, Geoffrey Washburn, and Stephanie Weirich. An open and shut typecase. In ACM SIGPLAN Workshop on Types in Language Design and Implementation (TLDI), Long Beach, CA, USA, January 2005. 15 pages. An extended version of this paper (50 pages) is University of Pennsylvania Technical Computer and Information Science Report MS-CIS-04-26.

Geoffrey Washburn and Stephanie Weirich. Boxes go bananas: Encoding higher-order abstract syntax with parametric polymorphism. 64 pages. Submitted for publication to Journal of Functional Programming, October 2004.

Stephanie Weirich and Liang Huang. A design for type-directed Java. In Viviana Bono, editor, Workshop on Object-Oriented Developments, ENTCS, 2004. 20 pages. An extended version (49 pages) of this paper is University of Pennsylvania Computer and Information Science Technical Report MS-CIS-04-11.

Simon Peyton Jones, Geoffrey Washburn, and Stephanie Weirich. Wobbly types: Practical type inference for generalised algebraic dataypes. 15 pages, July 2004.

Stephanie Weirich. Higher-order intensional type analysis in type erasure semantics. 29 pages. Accepted to Journal of Functional Programming, pending revision, 2004

Stephanie Weirich. Type-Safe Cast. To appear in Journal of Functional Programming. Published Online Jun 2004.

Geoffrey Washburn and Stephanie Weirich. Boxes go bananas: Encoding higher-order abstract syntax with parametric polymorphism. In/ ACM SIGPLAN International Conference on Functional Programming/, pages 249-262, Uppsala, Sweden, August 2003.

Karl Crary, Stephanie Weirich, and Greg Morrisett. Intensional polymorphism in type erasure semantics. Journal of Functional Programming, 12(6):567-600, November 2002.

Stephanie Weirich. Programming With Types. PhD thesis, Cornell University, August 2002.

Stephanie Weirich. Higher-order intensional type analysis. In Daniel Le Métayer, editor, 11th European Symposium on Programming, pages 98-114, Grenoble, France, April 2002.


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Karen I. Winey

Professor of Materials Science and Engineering; Professor of Chemical and Biomolecular Engineering
Email: winey at lrsm.upenn.edu
Personal Website   |   Research Website

Research Interests:
Ion-Containing Polymers: Morphologies of semi-crystalline and amorphous ionomers; Influences of materials chemistry and processing on ionomer morphologies; Molecular mechanisms of diffusion and permeability; Electron microscopy and x-ray scattering methods.
Nanocomposites: Fabrication of nanotube / polymer composites; Thermal, electrical and mechanical properties; X-ray scattering of nanotube materials.
Block Copolymers: Molecular mechanisms of deformation and alignment; Shear-induced structures and defects; Morphologies and mechanical properties in triblock copolymer systems.
Random Copolymers: Long-term drug delivery systems using PLGA; Blend miscibility in random copolymer systems.

Selected Recent Publications:
A. Budhian, S. J. Siegel, K. I. Winey. Production of haloperidol loaded PLGA nanoparticles for extended controlled drug release of haloperidol. Journal of Microencapsulation, in press.

F. Du, J. E. Fischer, K. I. Winey. Effect of nanotube alignment on percolation conductivity in carbon nanotube / polymer composites. Rapid Communication in Physical Review B, in press.

T. Kashiwagi, F. Du, J. F. Douglas, K. I. Winey, R. H. Harris, Jr., J. R. Shields. Nanoparticle networks reduce flammability polymer nanocomposites. Nature Materials, in press.

N. M. Benetatos, B. W. Smith, P. A. Heiney, K. I. Winey. Toward reconciling STEM and SAXS data from ionomers by investigating gold nanoparticles. Macromolecules, in press.

T. Kashiwagi, F. Du, I. Winey, et al. Flammability properties of polymer nanocomposites with single-walled carbon nanotubes: Effects of nanotube dispersion and concentration. Polymer, v 46, n 2, January 12, 2005, p 471-481.

F. Du,, R.C. Scogna, W. Zhou, et al. Nanotube networks in polymer nanocomposites: Rheology and electroconductivity. Macromolecules, v 37, n 24, November 30 2004, p 9048-9055.

H. Wang, W. Zhou, D.L. Ho, et al. Dispersing single-walled carbon nanotubes with surfactants: A small angle neutron scattering study. Nano Letters 4 (9): 1789-1793 September 2004.

W. Zhou, M. F. Islam, H. Wang, D. L. Ho, A. G. Yodh, K. I. Winey, J. E. Fischer. Small angle neutron scattering from single-wall carbon nanotube suspensions: Evidence for isolated rigid rods and rod networks. Chem. Phys. Lett., 384, 185-189, 2004.

W. Zhou, J. Vavro, C. Guthy, K. I. Winey, J. E. Fischer, L. M. Ericson, S. Ramesh, R. Saini, V. A. Davis, C. Kittrel, M. Pasquali, R. H. Hauge, R. E. Smalley. Single wall carbon nanotube fibers extruded from super-acid suspensions: Preferred orientation, electrical and thermal transport. J. Appl. Physics, 95, 649-655, 2004.

W. Zhou, K. I. Winey, J. E. Fischer, Sreekumar TV, Kumar S, Kataura. Out-of-plane mosaic of single-wall carbon nanotube films. H, Appl. Phys. Lett., 84, 2172-2174, 2004.

F. Du, J. E. Fischer, K. I. Winey. Coagulation method for preparing single-walled carbon nanotube/poly(methyl methacrylate) composites and their modulus, electrical conductivity, and thermal stability.J. Polym. Sci.: Polym. Phys., 41, 3333-3338, 2003.

R. Haggenmueller, W. Zhou, J. E. Fischer and K. I. Winey. Production and characterization of polymer nanocomposites with highly aligned single-walled carbon nanotubes. J. Nanoscience and Nanotechnology, 3, 105-110, 2003.

B. P. Kirkmeyer, R. Puetter, A. Yahil and K. I. Winey. Deconvolution of scanning transmission electron microscopy images of ionomers. J. Polym. Sci.: Polym. Phys., 41, 319-326, 2003.

A. Taubert, J. H. Ferris and K. I. Winey. Rapid preparation of a polymer fiber and a free-standing polymer film for cross-sectional microtomy. Microscopy Today, 11, 36-38, 2003.

A. Taubert, J. D. Wind, D. R. Paul, W. J. Koros, and K. I. Winey. Novel polyimide ionomers: CO2 plasticization, morphology, and ion distribution. Polymer, 44, 1881-1892, 2003.

B. P. Kirkmeyer, A. Taubert, J.-S. Kim and K. I. Winey. Vesicular ionic aggregates in poly(styrene-co-methacrylic acid) ionomers neutralized with Cs.Macromolecules, 35, 2648-2653, 2002.

L. Qiao, A. J. Ryan and K. I. Winey.A correlation between lamellar contraction and applied shear stress in diblock copolymer.Macromolecules, 35, 3596-3600, 2002.

S. J. Siegel, K. I. Winey, R. E. Gur, R. H. Lennox, D. Ikeda, N. Gandhi, W.-X. Zhang. Surgically implantable long-term antipsychotic delivery systems for the treatment of schizophrenia. Neuropsychopharmacology, 26, 817-823, 2002.

A. Taubert and K. I. Winey. Imaging and x-ray microanalysis of poly(ethylene-ran-methacrylic acid) ionomer melt neutralized with Sodium. Macromolecules, 35, 7419-7426, 2002.

R. W. Walters, K. E. Sohn, K. I. Winey and R. J. Composto.Local acid environments in poly(ethylene-ran-methacrylic acid) ionomers. Journal of Polymer Science: Part B: Polymer Physics Edition, 40, 2833-2841, 2002.


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Beth A. Winkelstein

Assistant Professor in Bioengineering, Neurosurgery; Member of the Institute for Medicine and Engineering
Email: winkelst at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Understanding the mechanisms of injury that produce whiplash, sports-related, and other painful injuries. Particular emphasis is placed on understanding injury to individual structures in the neck, such as the facet joints, nerve roots and spinal cord and how mechanical loading to these structures elicits pain. Research efforts incorporate modeling, computational modeling, injury analysis and neuroimmunologic techniques, among others, to begin to develop thresholds for mechanical injury that produce persistent pain; and work towards a definition of the neck's tolerance for painful injury.

Selected Recent Publications:

Quinn KP, Winkelstein BA. Defining Quasilinear Viscoelastic Parameters for the Rat Cervical Facet Capsular Ligament in Tension. BMES Annual Fall Meeting, #142032, accepted, 2005.

Rothman SM, Kreider RA, Winkelstein BA. Spinal Neuropeptide Responses in Persistent and Transient Pain Following Cervical Nerve Root Injury. Spine, in press, 2005.

Simon SL, Davis, MB, Odner D, Udupa JK, Winkelstein BA. CT Imaging Techniques for Describing Motions of the Cervicothoracic Junction and Cervical Spine During Flexion, Extension and Cervical Traction. Spine, in press, 2005.

Lee KE, Franklin AN, Davis MB, Winkelstein BA. Tensile Cervical Facet Capsule Ligament Mechanics: Failure and Subfailure Responses in the Rat. Journal of Biomechanics, in press, 2005.

Hubbard RD, Winkelstein BA. Transient Cervical Nerve Root Compression in the Rat Induces Bilateral Forepaw Allodynia and Spinal Glial Activation: Mechanical Factors in Painful Neck Injuries. Spine, 30(17): 1924-1932, 2005.

Lee KE, Franklin AN, Winkelstein BA. Subfailure Injuries of the Neck: Implications for Whiplash and Pain. International Whiplash Trauma Congress, Breckenridge, CO, February, 2005.

Rothman SM, Kreider RA, Winkelstein BA. Cervical Nerve Root Axotomy & Radiculopathy Produce Different Pain Symptoms & Spinal Neuropeptide Patterns Suggesting Separate Mechanisms of Acute & Chronic Pain. Orthopaedic Research Society 51st Annual Meeting, Poster/Short Talk #371, Washington DC, February, 2005.

Lee KE, Thinnes JH, Gokhin D, Winkelstein BA. A Novel Rodent Neck Pain Model of Facet-Mediated Behavioral Hypersensitivity: Implications for Persistent Pain and Whiplash Injury. Journal of Neuroscience Methods, 137(2):151-159, 2004.

Winkelstein BA, DeLeo JA. Mechanical Thresholds for Initiation and Persistence of Pain Following Nerve Root Injury: Mechanical and Chemical Contributions at Injury. Journal of Biomechanical Engineering, 126(2):258-263, 2004.

Davis M, Simon S, Odner D, Iwanaga T, Udupa JK, Winkelstein BA. Biomechanical Characterization of Cervicothoracic Junction Biomechanics Using CT Imaging. BMES 2004 Annual Fall Meeting, #1138, Philadelphia, PA, October, 2004.

Franklin AN, Lee KE, Winkelstein BA. Tensile Mechanical Characterization of the Rat Facet Capsule. BMES 2004 Annual Fall Meeting, Philadelphia, PA, October, 2004.

Lee KE, Davis MB, Mejilla RM, Winkelstein BA. In Vivo Cervical Facet Capsule Distraction: Mechanical Implications for Whiplash and Neck Pain. Proceedings of 48th Stapp Car Crash Conference, Paper #2004-22-0016, 48:373-393, 2004.

Winkelstein, B.A. Mechanisms of Central Sensitization, Neuroimmunology & Injury Biomechanics in Persistent Pain: Implications for Musculoskeletal Disorders." Journal of Electromyography & Kinesiology, 14(1): 87-93, 2004.

Winkelstein, B.A., DeLeo, J.A. Mechanical Thresholds for Initiation and Persistence of Pain Following Nerve Root Injury: Mechanical and Chemical Contributions at Injury. Journal of Biomechanical Engineering, 126(2):258-263, 2004.

Hubbard R, Rothman S, Winkelstein B. Mechanisms of Persistent Neck Pain Following Nerve Root Compression Injury: Understanding Behavioral Hypersensitivity in the Context of Spinal Cytokine Responses and Tissue Biomechanics. North American Spine Society 19th Annual Meeting, #P49, Chicago, IL, October, 2004.

Rothman SM, Kreider RA, Winkelstein BA. Understanding Mechanisms of Painful Cervical Nerve Root Injury: Defining a Relationship Between Persistent and Resolving Neck Pain Symptoms and Spinal Neuropeptide Responses. Cervical Spine Research Society 32nd Annual Meeting, Paper #38, Boston, MA, December, 2004.

Hubbard, R.D., Lee, K.E., Winkelstein, B.A. Effects of Nerve Root Compression Magnitude on Behavioral Outcomes: Preliminary Findings in a Neck Pain Model. National Neurotrauma Society Meeting, #340. Biloxi, MS, November, 2003.

Winkelstein, B.A., Hubbard, R.D., DeLeo, J.A. Biomechanics and Painful Injuries: Tissue & CNS Responses for Nerve Root Mechanical Injuries. ASME International Mechanical Engineering Conference, #IMECE2003-43117, Washington DC, November, 2003.

Lee, K.E., Thinnes, J.H., Gokhin, D., Winkelstein, B.A. Preliminary Findings in a Novel Facet-Mediated Neck Pain Model: Biomechanical Implications for Whiplash Injuries. International Whiplash Trauma Congress, Abstract #2, Denver, CO, October, 2003.

DeLeo, J.A., Winkelstein, B.A. Physiology of Chronic Spinal Pain Syndromes: From Animal Models to Biomechanics. Spine, 27(22):2526-2537, 2002.

Nightingale, R.W., Winkelstein, B.A., Knaub, K.E., Richardson, W.J., Luck, J.F., Myers, B.S. Comparative Strengths and Structural Properties of the Upper and Lower Cervical Spine in Flexion and Extension. Journal of Biomechanics, 35(6):725-732, 2002.

Rutkowski, M.D., Winkelstein, B.A., Hickey, W.F., Pahl, J.L., DeLeo, J.A. Lumbar Nerve Root Injury Induces CNS Neuroimmune Activation and Neuroinflammation in the Rat: Relationship to Painful Radiculopathy. Spine, 27(15):1604-1613, 2002.

Winkelstein, B.A., DeLeo, J.A. Nerve Root Tissue Injury Severity Differentially Modulates Spinal Glial Activation in a Rat Lumbar Radiculopathy Model: Considerations for Persistent Pain. Brain Research, 956(2):294-301, 2002.

Winkelstein, B.A., Myers, B.S. Importance of Nonlinear and Multivariable Flexibility Coefficients in the Prediction of Human Cervical Spine Motion. Journal of Biomechanical Engineering, 124(5):504-511, 2002.

Winkelstein, B.A., Weinstein, J.N., DeLeo, J.A. Role of Local Biomechanics in Temporal Behavioral Responses of Painful Radiculopathy. 4th World Congress of Biomechanics, #5057, Calgary, Canada, August, 2002.

Winkelstein, B.A., Weinstein, J.N., DeLeo, J.A. The Role of Mechanical Deformation in Lumbar Radiculopathy: An In Vivo Model. Spine, 27(1):27-33, 2002.


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Wayne L. Worrell

Professor of Materials Science and Engineering
Email: worrell at lrsm.upenn.edu
Personal Website

Research Interests:
Chemical, electrochemical and electrical properties of novel materials at elevated temperatures. Their applications in fuel cells, catalysis, and as oxygen-separation membranes and protective coatings. Current research programs include mixed-conducting oxides for solid-oxide fuel cells (SOFCs) and oxygen separation membranes, reduce-temperature SOFCs, anodes for direct oxidation of methane in SOFCs, and high temperature oxidation of materials.

Selected Recent Publications:
Lu, C., An, S., Worrell, W.L., et al. Development of intermediate-temperature solid oxide fuel cells for direct utilization of hydrocarbon fuels. Solid State Ionics 175(1-4): 47-50 Sp. Iss. SI November 30 2004.

An, S., Lu, C, Worrell, W.L. et al. Characterization of Cu-CeO2 direct hydrocarbon anodes in a solid oxide fuel cell with lanthanum gallate electrolyte. Solid State Ionics 175 (1-4): 135-138. Sp. Iss. SI November 30, 2004.

An, S., Lu, C., Worrell, W. L., Vohs, J. M., Gorte, R. J. Scandia stabilized zirconia (ScSZ) SOFCs for the direct oxidation of hydrocarbon fuels. Proceedings - Electrochemical Society, 2002-26(Solid-State Ionic Devices III), 66-72, 2003.

Lu, C., Gorte, R. J., Worrell, W. L., Vohs, J. M. Thin-film samaria doped ceria SOFCs for direct oxidation of hydrocarbon fuels at intermediate temperatures. Proceedings - Electrochemical Society, 2002-26(Solid- State Ionic Devices III), 73-80, 2003.

Lu, C., Worrell, W.L., Vohs, J.M., Gorte, R.J. A Comparison of Cu-Ceria-SDC and Au-Ceria-SDC Composites for SOFC Anodes. Journal of the Electrochemical Society, v 150, n 10, October, 2003, p A1357-A1359.

Lu, C., Worrell, W.L., Gorte, R.J., Vohs, J.M. SOFCs for direct oxidation of hydrocarbon fuels with samaria-doped ceria electrolyte. Journal of the Electrochemical Society, v 150, n 3, March 2003, p A354-8.

Huang, Jiu-Qi, Worrell, Wayne L.. Synthesis and characterization of mixed- conducting praseodymia-doped yttria-stabilized zirconia. Proceedings - Electrochemical Society, 2002-5(High Temperature Materials), 16-25, 2002.

Lu, C., Worrell, W.L., Wang, C., Park, S., Kim, H., Vohs, J.M., Gorte, R.J. Development of solid oxide fuel cells for the direct oxidation of hydrocarbon fuels. Solid State Ionics, Diffusion & Reactions, v 152-153, Dec. 2002, p 393-7.

Kim, H., Lu, C., Worrell, W.L., Vohs, J.M., Gorte, R.J. Cu-Ni cermet anodes for direct oxidation of methane in solid-oxide fuel cells. Journal of the Electrochemical Society, v 149, n 3, March 2002, p A247-50.

Lu, C., Worrell, W. L., Kim, H., Gorte, R. J., Vohs, J. M. Characterization of a Cu0.8Ni0.2-CeO2-YSZ anode-composite for the direct oxidation of dry methane. Proceedings - Electrochemical Society, 2002-5(High Temperature Materials), 88-96, 2002.

Lu, C., Worrell, W. L., Vohs, J. M., Gorte, R. J. Characterization of SDC electrolyte-supported SOFCs for direct oxidation of hydrocarbon fuels. Proceedings - Electrochemical Society, 2002-5 (High Temperature Materials), 72-78, 2002.

Ramberg, C.E., Worrell, W.L. Oxidation kinetics and composite scale formation in the system Mo(Al,Si)/sub 2/. Journal of the American Ceramic Society, v 85, n 2, Feb. 2002, p 444-52.

Wang, Conghua, Worrell, Wayne L.. Effect of synthesis on the phases in scandia-stabilized zirconia (ScSZ). Proceedings - Electrochemical Society, 2002-5 (High Temperature Materials), 9-15, 2002.

Worrell, Wayne L. The solid-solubility limits, mixed-conductivity and electrode performance of cation-doped cubic YSZ. Proceedings - Electrochemical Society, Volume Date 2001, 2001-28(Ionic and Mixed Conducting Ceramics), 75-89, 2002.


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Shu Yang

Skirkanich Assistant Professor of Materials Science and Engineering
Email: shuyang at seas.upenn.edu
Personal Website   |   Research Website

Research Interests:
Synthesis, characterization and fabrication of functional polymers, and organic/inorganic hybrids. Special interests include preparation of functional block copolymers and investigation of their nanostructures; understanding the self-organization process at surfaces and interfaces; development of novel photosensitive materials and non-conventional approaches for nano- and micropatterning of complex 2D and 3D structures; controlling liquid wetting/dewetting behavior on polymer thin films.

Selected Recent Publications:
Moon, JH; Kim, WS; Ha, JW; Jang, SG; Yang, SM; Park, JK. Colloidal lithography with crosslinkable particles: fabrication of hierarchical nanopore arrays. CHEMICAL COMMUNICATIONS, (32): 4107-4109 2005.

Moon, J. H., Yang, S., “Creating three-dimensional polymeric microstructures by multi-beam interference lithography” Journal of Macromolecular Science, Part C: Polymer Reviews. accepted. (invited review)

Yang, S.; Ullal, C. K.; Thomas, E. L.; Chen, G; Aizenberg, J. “Microlens Arrays with Integrated Pores as a Multipattern Photomask”, Appl. Phys. Lett. 2005, 86, 201121.

Yang, S.; Chen, G; Megens, M.; Ullal, C. K.; Han, Y.-J.; Rapaport, R.; Thomas, E. L.; Aizenberg, J. “Functional Biomimetic Microlens Arrays with Integrated Pores”, Adv. Mater. 2005, 17, 435.

Fukukawa, K.; Zhu, L.; Gopalan, P.; Ueda, M.; Yang, S., “Synthesis and Characterization of Silicon-containing Block Copolymers from
Nitroxide-mediated Living Free Radical Polymerization”, Macromolecules, 2005, 38, 263-270.

Jeon, S.; Park, J.-U.; Cirelli, R.; Yang, S., Heitzman, Carla E.; Braun, Paul V.; Kenis, Paul J. A. and Rogers, J. A. “Fabricating complex
three-dimensional nanostructures with high-resolution conformable phase masks”, Proc. Natl. Acad. Sci. USA, 2004, 101: 12428-12433.

Ullal, C K; Maldovan, M.; Thomas, E. L.; Chen, G; Han, Y.-J.; and Yang, S. “Photonic crystals through holographic lithography: simple cubic, diamond like and gyroid like structures”, Appl. Phys. Lett. 2004, 84, 5434.

Krupenkin, T. N.; Taylor, J.A.; Schneider, T. M.; Yang, S. “From Rolling Ball to Complete Wetting on Dynamically Tunable Nanostructured Surfaces”, Langmuir, 2004, 20, 3824.

Yang, S.; Mirau, P.; Sun, J. N.; Gidley, D.“Characterization of nanoporous ultra Low-k thin films templated by copolymers with different
architectures” Rad. Chem. Phys. 2003, 68, 351.

Yang, S.; Krupenkin, T. N.; Mach, P. and Chandross, E. A. “Fabrication of tunable and latchable liquid microlens with photopolymerizable components” Adv. Mater. 2003, 15 (11), 940.

Krupenkin,T. N.; Yang, S.; Mach, P. “Tunable liquid microlens” Appl. Phys. Lett. 2003, 82, 316

Cattaneo, F.; Baldwin, K.; Yang, S.; Krupenkin, T. N. and Rogers, J.A. “Digitally Tunable Microfluidic Optical Fiber Devices”, J. Microelectromech. Sys.,2003, 12, 907.

Hsieh, J. Mach, P.; Cattaneo, F.; Yang, S.; Krupenkin, T.; Baldwin K. and Rogers, J. A. “Tunable microfluidic optical fiber devices based on molded plastic microchannels and electrowetting pumps”, IEEE Photon. Techn. Lett. 2003, 15, 81.

Ullal, C. K.; Maldovan, M.; Wohlgemuth, M.; White, C. A.; Yang, S. and Thomas, E. L. “3D periodic biocontinuous structures through interference lithography: a level set approach”, J. Opt. Soc. Am. A., 2003, 20, 948.

Yang, S.; Horibe, Y.; Chen, C.-H.; Mirau, P.; Tatry, T.; Evans, P.; Grazul, J.and Dufresne, E. M. “Ordered hydrophobic organosilicates templated by block copolymers” Chem. Mater. 2002, 14, 5173.

Yang, S.; Megens, M.; Aizenberg, J.; Wiltzius, P.; Chaikin, P.; Russel, W. “Visible laser-initiated cationic polymerization for multi-beam
interference lithography”, Chem. Mater. 2002, 14, 2831.

Yang, S.; Mirau, P.A.; Pai, C.-S.; Nalamasu, O.; Reichmanis, E.; Pai, J. C.; Obeng, Y. S.; Seputro, J.; Lin, E.; Lee, H.-J.; Sun, J. and Gidley, D. “Nanoporous ultralow dielectric constant organosilicates templated by triblock copolymers”, Chem. Mater. 2002, 14, 369.

Mirau, P. A. and Yang, S. “Solid state proton NMR characterization of ethylene oxide and propylene oxide random and block copolymer composites with poly(methyl silsesquioxanes)”, Chem. Mater, 2002, 14, 249.

Xu, J.; Moxom, J.; Yang, S.; Suzuki, R. and Ohdaira, T. “Porosity in porous methyl-silsesquioxane (MSQ) Films” Appl. Surf. Sci., 2002, 194, 189.

Xu, J.; Moxom, J.; Yang, S.; Suzuki, R. and Ohdaira, T. “Dependence of porosity in methyl-silsequioxane thin films on molecular weight of
sacrificial triblock copolymers”, Chem. Phys. Lett. 2002, 363, 309.

Mach, P.; Krupenkin, T. N.; Yang, S. and Rogers, J. A. “Dynamic tuning of optical waveguides with electrowetting pumps and recirculating fluid channels”, Appl. Phys. Lett., 2002, 81, 202.


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Mark Yim

Associate Professor of Mechanical Engineering and Applied Mechanics; Gabel Family Term Junior Professor of Mechanical Engineering
Email: yim at grasp.upenn.edu
Personal Website   |   Research Website

Research Interests:
Modular reconfigurable robots and locomotion, PolyBot; MEMS and batch fabrication techniques; brute force digital time optimal control.

Selected Recent Publications:
Zhang, Y., Ackerson, L. Duff, D., et al. Stam: A system of tracking and mapping in real environments. IEEE Wireless Communications, v 11, n 6, December 2004, p 87-96.

Golovinsky, A., Yim, M., Zhang, Y., et al. PolyBot and PolyKinetic system: A modular robotic platform for education. IEEE International Conference on Robotics and Automation, 2004, p 1381-1386.

Eldershaw, C., Yim, M., Zhang, Y., Roufas, K. and Duff, D. Motion planning with narrow Cspace passages, Proc. of the IEEE/RSJ Intl. Conf. on Intelligent Robots and Systems (IROS), Las Vegas, 2003.

Yim, M., Eldershaw, C., Zhang, Y. and Duff, D., Self-Reconfigurable Robot Systems: PolyBot. Journal of the Robotics Society of Japan Vol.21, No.8, Nov. 2003.

Yim, M., Roufas, K., Duff, D., Zhang, Y., Eldershaw, C., and Homans, S. Modular ReconfigurableRobots in Space Applications. Autonomous Robots Special Issue on Space Applications Vol.14, No.2/3 March/May. 2003.

Zhang, Y., Roufas, K., Eldershaw C., Yim, M., and Duff, D. Sensor Computation in Modular Self-Reconfigurable Robots. Experimental Robotics VIII, Advanced Robotics Series, Bruno Siciliano Ed. Springer, 2003.

Zhang, Y., Yim, M., Eldershaw, C., Duff, D. and Roufas, K. Phase Automata: a programming model of locomotion gaits for scalable chain-type modular robots. Proc. of the IEEE/RSJ Intl. Conf. on Intelligent Robots and Systems (IROS), Las Vegas, 2003.

Zhang, Y., Yim, M., Eldershaw, C., Duff, D. and Roufas, K. Scalable and reconfigurable configurations and locomotion gaits for chain-type modular reconfigurable robots. Proc. of the IEEE Symp. on Computational Intelligence in Robotics and Automation (CIRA), Japan, 2003.

Yim, M., Duff, D.G. and Roufas, K.D. Walk on the wild side. IEEE Robotics and Automation Magazine, Special Issue on Distributed Robotics, Vol.8, No.4, Dec. 2002.

Yim, M., Zhang, Y., Roufas, K., Duff, D., and Eldershaw, C. Connecting and Disconnecting for Chain Self-Reconfiguration with PolyBot. IEEE/ASME Transactions on Mechatronics, Special Issue on Self-Reconfigurable Robots Vol.7, No.4, pp 431-441, Dec. 2002.

Agrawal, S.K., Kumar, S., and Yim, M.Polyhedral Single Degree-of-freedom Expanding Structures:Design and Prototypes. ASME J. of Mechanical Design, Vol.124, No.3, pp 361-590 Sept.2002.

Zhang, Y., Yim, M., Roufas, K., Eldershaw, C., and Duff, D. Attribute/Service Model: Design Patterns for Distributed Coordination of Sensors, Actuators and Tasks. Proc. of IEEE Workshop on Embedded System Codesign (ESCODES), San Jose, CA, Sept. 24, 2002.

Suh, J.W., Homans, S.B., and Yim, M. Telecubes: Mechanical Design of a Module for Self-Reconfigurable Robotics. Proc. of the IEEE Intl. Conf. on Robotics and Automation, (ICRA), Washington D.C., May 11-15, 2002.

Vassilvitskii, S., Kubica, J., Rieffel, E., Suh, J.W. and Yim, M. On the General Reconfiguration Problem for Expanding Cube Style Modular Robots. Proc. of the IEEE Intl. Conf. on Robotics and Automation, (ICRA), Washington D.C., May 11-15, 2002.

Vassilvitskii, S., Suh, J.W. and Yim, M. A Complete, Local and Parallel Reconfiguration Algorithmfor Cube Style Modular Robots. Proc. of the IEEE Intl. Conf. on Robotics and Automation, (ICRA), Washington D.C., May 11-15, 2002.

Zhang, Y., Roufas, K., Yim, M., and Eldershaw, C. Massively Distributed Control Nets for Modular. Self-Reconfigurable Robots, Proc. of AAAI Spring Symposium Series, March 25-27 2002.

Yim, M., Zhang, Y. and Duff, D. Modular Reconfigurable Robots, Machines that shift their shape to suit the task at hand.IEEE Spectrum Magazine cover article, Feb. 2002.

Zhang, Y., Eldershaw, C., Yim, M., Roufas, K. and Duff, D. A Platform for studying locomotion systems: Modular Self-Reconfigurable Robots. Proc. of NIST workshop on Performance Metrics for Intelligent Systems (PerMIS), Gaithersburg, MD, Aug. 13-15, 2002.

Eldershaw, C., Yim, M., Duff, D., Roufas, K. and Zhang, Y. Modular self reconfigurable robots.Proc. of Robotics for Future Land Warfare Workshop. DSTO Edinburgh, Australia, May 23-24, 2002.


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Steve Zdancewic

Assistant Professor of Computer and Information Science
Email: stevez at cis.upenn.edu
Personal Website

Research Interests:
I study programming languages and computer security. Most recently, my work has focused on language-based enforcement of information-flow policies and understanding declassification. I am also interested in secure concurrent and distributed computing, functional programming languages, type theory, linear logic, theorem proving and mechanized metatheory.

Selected Recent Publications:

Brian E. Aydemir, Aaron Bohannon, Matthew Fairbairn, J. Nathan Foster, Benjamin C. Pierce, Peter Sewell, Dimitrios Vytiniotis, Geoffrey Washburn, Stephanie Weirich, and Steve Zdancewic. Mechanized Metatheory for the Masses: The POPLMark Challenge. In International Conference on Theorem Proving in Higher Order Logics (TPHOLs), 2005.

Michael Hicks, Stephen Tse, Boniface Hicks, and Steve Zdancewic. Dynamic updating of information-flow policies. In Proc. of Foundations of Computer Security Workshop, 2005.

Peng Li and Steve Zdancewic. Unifying Confidentiality and Integrity in Downgrading Policies. In Proc. of Foundations of Computer Security Workshop, 2005.

Stephen Tse and Steve Zdancewic. Designing a Security-typed Language with Certificate-based Declassification. In Proc. of the 14th European Symposium on Programming, 2005. To appear.

Peng Li and Steve Zdancewic. Practical Information-flow Control in Web-based Information Systems. In Proc. of 18th IEEE Computer Security Foundations Workshop, pages 2-15, 2005.

Peng Li and Steve Zdancewic. Downgrading Policies and Relaxed Noninterference. In Proc. 32nd ACM Symp. on Principles of Programming Languages (POPL), pages 158-170, January 2005.

Steve Zdancewic. Challenges for Information-flow Security. In Proceedings of the 1st International Workshop on the Programming Language Interference and Dependence (PLID’04) 2004.

Stephen Tse and Steve Zdancewic. Translating Dependency into Parametricity. In Proc. of the 9th ACM SIGPLAN International Conference on Functional Programming, September 2004.

Andrew Myers, Andei Sabelfeld, and Steve Zdancewic. Enforcing Robust Declassification. In Proc. of 17th IEEE Computer Security Foundations Workshop, June 2004.

Peng Li and Steve Zdancewic. Advanced Control Flow in Java Card Programming. In Proc. of the 2004 ACM SIGPLAN Conference on Languages, Compilers, and Tools for Embedded Systems. ACM Press, June 2004.

Stephen Tse and Steve Zdancewic. Run-time Principals in Information-flow Type Systems. In IEEE 2004 Symposium on Security and Privacy. IEEE Computer Society Press, May 2004.

Peng Li, Yun Mao, and Steve Zdancewic. Information Integrity Policies. In Proceedings of the Workshop on Formal Aspects in Security & Trust (FAST), September 2003.

David Walker, Steve Zdancewic, and Jay Ligatti. A Theory of Aspects. In Proc. of the 8th ACM SIGPLAN International Conference on Functional Programming, Upsala, Sweden, August 2003.

Usa Sammapun, Raman Sharykin, Margaret Delap, Myong Kim, and Steve Zdancewic. Formalizing Java-MaC. In Proceedings of the Third Runtime Verification Workshop. Electronic Notes in Theoretical Computer Science, July 2003.

Steve Zdancewic and Andrew C. Myers. Observational Determinism for Concurrent Program Security. In Proc. of 16th IEEE Computer Security Foundations Workshop, July 2003.

Michael Greenwald, Carl A. Gunter, Björn Knutsson, Andre Scedrov, Jonathan M. Smith, and Steve Zdancewic. Computer Security is Not a Science (but it should be). In Proceedings of the Large-Scale Network Security Workshop, March 2003.

Steve Zdancewic. A Type System for Robust Declassification. In Proceedings of the Nineteenth Conference on the Mathematical Foundations of Programming Semantics. Electronic Notes in Theoretical Computer Science, March 2003.

Lantian Zheng, Stephen Chong, Steve Zdancewic, and Andrew C. Myers. Building Secure Distributed Systems Using Replication and Partitioning. In IEEE 2003 Symposium on Security and Privacy. IEEE Computer Society Press, 2003.

Steve Zdancewic and Andrew C. Myers. Secure Information Flow via Linear Continuations. Higher Order and Symbolic Computation, 15(2/3), 2002.

Steve Zdancewic, Lantian Zheng, Nathaniel Nystrom, and Andrew C. Myers. Secure Program Partitioning. Transactions on Computer Systems, 20(3):283-328, 2002.


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