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Associate Professor,
Ph.D., University of Maryland.
Joint Appointment with IPR
Research Interests
Dr. Lawson’s research interests lie predominantly in the areas of relativistic electronics and high power microwave sources, components, and applications. His current research on microwave sources is concentrated on gyrotron amplifiers and novel hybrid slow wave/fast wave amplifiers. The gyrotron amplifier studies are intended to lead to devices with output powers above 100 MW for 1 microsecond with gains and efficiencies exceeding 50 dB and 40%, respectively. The targeted frequency range is 8-30 GHz. Such devices will make suitable RF drivers for the next generation of linear colliders. The goal of the hybrid amplifier studies is to produce high efficiency, low magnetic field, low voltage, and narrow and broadband amplifiers for a variety of applications. This pioneering work utilizes non-adiabatic magnetic transitions to combine the benefits of slow wave and fast wave devices in a single microwave tube. The high power microwave component research includes theoretical and experimental work on the design of various overmoded coaxial and circular waveguide components. The list of hardware under investigation includes nonlinear waveguide transitions mode converters and injectors, directional couplers, filters, and absorbers.
Professional Service
Conf. Session Chairs: IEEE ICOPS - Fast Wave Millimeter Wave Devices; IEDM - Vacuum Electronics Subcommittee. Chair, IEDM - Vacuum Electronics Subcommittee.
University Service
EE Committees: Academic Affairs; Undergraduate Affairs; Promotions and Tenure ; Chair, Ad Hoc Curriculum Revision . Senior Faculty Teaching Award Committee.
Recent Publications
Professor,
Ph.D., Harvard University.
IEEE Fellow, Optical Society of America Fellow, Photonics Society of Chinese-
Americans Fellow
Research Interests
Dr. Lee’s research interests are in the area of ultrashort-pulse lasers and ultrafast optoelectronics. This includes all aspects of ultrashort-pulse lasers, from generation and characterization of optical pulses to a wide range of applications using the ultrashort pulses.
His current research activities can be categorized into two groups: (1) ultrashort-pulse laser technology and (2) RF optoelectronic applications using ultrafast optical techniques. In the laser technology area, several projects are being pursued. They include the development of a versatile, multi-use, ultrashort-pulse laser system for research in atomic, molecular, and optical science and engineering. The system will deliver picosecond through femtosecond pulses with variable repetition rate, tunable wavelength, and output energy up to 1 mj. RF optoelectronic applications include: optical control devices for millimeter-wave and phased array systems, on wafer optoelectronic characterization of MMICs, ultra-wide-band and terahertz radiation. In addition, he is also working on the high power ultrashort pulse semiconductor laser using multiple quantum well structures as the compact laser source for ultrafast photoconductive switching of circuit elements and optoelectronic high temperature superconductor devices.
Professional Service
Technical Program Committee of the 1992-1996 IEEE MTT-S Intl. Microwave Symp.; Editorial Board, Microwave and Optical Tech. Lett.; Vice President, Photonics Society of Chinese-Americans, 1996.
University Service
Ward Chair Professorship Search Committee; Intl. Exchange Agreement Committee; China Committee; Search Committee for an Administrator for the Block Grant.
Recent Publications
Professor,
Ph.D., Massachusetts Institute of Technology.
IEEE Fellow
Research Interests
Dr. Levine’s research emphasizes two broad areas: control system design and the control of biomechanical systems. Specific current projects in control design include development of an interactive software package for the design of rotorcraft control systems, research on the computation of optimal controls, research on robust adaptive control, research on controlling the shape of large reflectors, and research on the control of aircraft at high angle of attack. Specific current projects in the control of biomechanical systems include development of a mathematical and computer-graphic model of the cricarytenoid joint of the human larynx, development of algorithms for interpolating data from ultrasound scans of the tongue into moving 3-dimensional images of the tongue’s surface, and research on the muscular controls that maximize the speed attained by a bicyclist.
The research on control system design has the long-term goal of understanding the control of multi-input multi-output systems. Such systems are becoming more and more common as sensors and actuators become less expensive and as economic pressures drive system designers to try for greater and greater efficiency of operation.
The research on biocontrols is intended to contribute to the long-term goals of understanding how humans control their voluntary movements and of providing movement aids for individuals, such as those with cerebral palsy, who have some form of difficulty controlling their movements.
University Service
EE: Chair, Ad Hoc Subcommittee of Graduate Studies Research Committee; General Academic Affairs Committee; Graduate Studies and Research Committee.
Recent Publications
Professor Emeritus,
D.E.E., Polytechnic of Brooklyn.
IEEE Life Fellow
Research Interests
Dr. H.C. Lin’s research interests are in the general area of integrated circuits and semiconductor devices. His current interest is in the application of Resonant Tunneling Diodes (RTD) for multiple-valued digital circuit and fuzzy logic. RTDs have very high response and unique folding characteristics. The use of these devices can result in circuit simplification and high speed. RTD analog-to-digital converters and multi-valued memories have been developed.
University Service
Engineering Innovation Hall of Fame Committee.
Recent Publications
Associate Professor,
Ph.D., University of California, Los Angeles.
Joint Appointment with ISR,
NSF National Young Investigator
Research Interests
Dr. Liu’s research interests span all aspects of high performance computational signal processing including parallel and distributed processing, fast algorithm, VLSI, and concurrent architecture, with application to image/video, radar/sonar, communications, and medical and biomedical technology.
His current research activities include but are not limited to the following projects: design and implementation of high-speed, low-power signal/image processing systems; development of low-complexity/real-time schemes for motion estimation and video coding/processing; applications of wavelet theory to tomography and computed imaging; development of intelligent computer-aided diagnosis systems for medical imaging; application of signal processing/array processing to wireless communications; analysis and development of blind equalization and identification algorithms; design and investigation of spectral estimation techniques for NMR spectroscopy for protein structure determination.
Professional Service
Assoc. Editor, IEEE Trans. on Signal Processing; Editor, VLSI Signal Processing; Deisgn and Implementation of Signal Processing Technical Committee, IEEE Signal Processing Soc.; Session Chair, IEEE Intl. Conf. on Image Processing (ICIP), Washington, D.C., Oct. 1995; IEEE Intl.Conf. on Acoustic, Speech, and Signal Processing (ICASSP), Detroit, MI, May 1995; Technical Program Committee, IEEE Intl. Conf. on Image Processing (ICIP), 1995; Program Committee, IEEE Workshop on VLSI Signal Processing, Saikai, Japan, Oct. 1995; Board of Directors, Mei-Hwa Chinese School, Silver Spring, Maryland.
University Service
EE: Dept. Council; Search Committee for Chair; Graduate Studies and Research Committee; Faculty Recruitment Committee; Ad Hoc Committee on Graduate Student Recruitment. ISR: Executive Committee; Chair, Education Program Committee; Faculty Coordinator for Seminar and Student-Faculty Colloquia Series; Chair, 1995 Elections Board; Salary Committee.
Recent Publications
Professor,
Ph.D., University of Kentucky.
Joint Appointment with ISR,
NSF Presidential Young Investigator
Research Interests
Dr. Makowski’s research interests broadly lie in applying advanced methods from the theory of stochastic processes to the modeling and design of a variety of engineering systems. Particular emphasis has been given to issues of performance modeling and analysis, and to problems of dynamic stochastic optimization as they arise in hybrid terrestrial and satellite networking applications.
Recent research interests include the use of asymptotic methods for the performance evaluation of switching systems, long-range dependence modeling for multimedia applications in high-speed networks, and stochastic control formulation of resource allocation issues in wireless networks (e.g., handoffs and paging). He is also currently involved in several industry-sponsored projects dealing with ATM technology.
Professional Service
Assoc. Editor, Discrete Event Dynamic Systems - Theory & Applications; Scientific Program Committee, Les XXVIIIe Journées de Statistique (ASU), Québec City (PQ), May 1996.
University Service
ISR Assoc. Director for Research; Chair, ISR Postdoc Selection Committee; ISR Representative, Engineering Council.
Recent Publications
Professor,
Ph.D., Massachusetts Institute of Technology.
Director, ISR, Joint Appointment with ISR,
IEEE Fellow
Research Interests
Dr. Marcus’ research interests are in the areas of control and systems engineering, stochastic systems, discrete event systems, and fault detection, with applications in manufacturing and communication networks.
His research spans both discrete and continuous time stochastic control problems. In discrete time, his research has focused on hidden Markov models, motivated by quality control problems arising in manufacturing. In particular, he is conducting an extensive research program in the adaptive estimation and control of Hidden Markov Models. Current research focuses on problems with robust and risk-sensitive cost, and on the application of these adaptive methods to problems of reinforcement learning. In continuous time, motivated by flexible manufacturing applications, his research has been concerned with hybrid control problems (controlled switching diffusions) involving both continuous and discrete states. Another current activity involves the application of adaptive control techniques to fault detection methodologies, with application to semiconductor manufacturing.
Motivated by problems in intelligent control, communication networks, and manufacturing, he is also conducting research on the control of discrete event dynamical systems. In supervisory control problems, one is interested in synthesizing a controller (or supervisor) in such a way that the closed loop system has acceptable behavior. His research has involved the solution of supervisor synthesis problems with incomplete observations, the derivation of explicit formulas and efficient algorithms for minimally restrictive supervisors, and the study of stability for such systems. His current research is focused on the development of on-line supervisor synthesis algorithms, and on the development of supervisory control algorithms for systems involving failures, such as those arising in semiconductor manufacturing.
Professional Service
Co-Managing Editor, Acta Applicandae Mathematicae; Assoc. Editor, Math. of Control, Signals, and Sys.; Assoc. Editor, J. Discrete Event Dynamic Sys.; Editor, SIAM J. Control and Optimization; Program Committee, Math. Theory of Networks and Sys.’96.
University Service
Chair, ISR Strategic Planning Committee; College of Engineering Administrative Council; Search Committee for Dean of Engineering; Search Committee for EE Chair; UMIACS Director Search Committee.
Recent Publications
Professor,
Ph.D., Institute of Cybernetics, Ukrainian Academy of Science, USSR.
IEEE Fellow, Research Fellow of GE, Research and Development Center, IEEE Magnetic Society Distinguished Lecturer, Distinguished Scholar/Teacher Award
Research Interests
Dr. Mayergoyz’s research interests are in the general areas of magnetics, electromagnetics, semiconductor device modeling, and power engineering. His current research activities are heavily focused in the areas of mathematical models for hysteresis (with special emphasis on magnetic and superconducting hysteresis), magnetic force microscopy and its applications to magnetic recording and data retrieval from magnetic media, analysis of electromagnetic fields in media with hysteresis, and numerical techniques for the calculation of 3-D electromagnetic fields. Another component of his research activity is numerical modeling of semiconductor devices by using drift-diffusion, hydrodynamic and Boltzmann-Poisson models as well as noise analysis in semiconductor devices from the semi-classical transport point of view.
Professional Service
Consulting Editor for Academic Press; Coordinator of Distinguished Lecturer Program of the IEEE Magnetic Society.
University Service
College Council; Undergraduate Affairs Committee; Applied Mathematics Committee; Curriculum Revision Committee.
Recent Publications
Professor,
Ph.D., Carnegie Melon University.
Joint Appointment with IPR
Research Interests
The research work of Dr. John Melngailis is in the use of ion beams in microfabrication. This includes both focused (point) beams and ion image projection. Focused ion beams are used in the semiconductor industry for local circuit rewiring, for failure analysis, and for mask repair. These applications depend on ion beam induced deposition, ion milling, and gas assisted ion etching. Our efforts are aimed at improving and expanding the usefulness of these techniques by understanding the beam induced microchemistry operating at dimensions below 50 nm and by developing new applications. A new effort is also being launched on the application of higher energy focused ion beam systems to direct maskless, resistless implantation of semiconductor devices. This technique permits the properties of semiconductors to be altered by doping with less than 0.1 µm lateral resolution opening the door to new types of devices.
Ion image projection is a promising technique for future chip fabrication. At present, photolithography is still being used to define the patterns on semiconductor chips down to 0.35 µm minimum linewidth. As minimum dimensions shrink to 0.1 µm and below, a new kind of lithography will need to be developed. The University of Maryland is working in a consortium of U.S. companies, government laboratories, and universities to develop ion projection lithography for future chip fabrication. The work being done here at present includes mask modeling, negative ion source development, and ion resist research.
Professional Service
Section Head for Electron Ion and Photon Beam Symposium.
University Service
Graduate Studies and Research Committee; Ward Chair Search Committee for EE; Senate Committee on Research; Promotion and Tenure Committee; Dept. Chair Search Committee.
Recent Publications
Associate Professor,
Ph.D., Princeton University.
Joint Appointment with IPST, NSF
Presidential Young Investigator,
Fellow, American Physical Society
Research Interests
Professor Milchberg’s research interests are in the area of laser-matter interactions. With use of state-of-the-art high power, ultrashort pulse lasers (which his group designs and builds), his activities encompass the regimes of linear through strongly nonlinear nonperturbative optics. The research is highly interdisciplinary, including elements of solid state physics, atomic physics, plasma physics, and quantum electronics. Applications of these studies include efficient sources of coherent X-rays (extreme harmonics or X-ray lasers) for use in imaging or patterning applications and compact table-top GeV electron accelerators. Among recent results which will bring such applications closer to reality was the first ever demonstration by his group of the optical guiding of ultrahigh intensity laser pulses.
Professional Service
Program Committee, CLEO/QELS Meeting, Baltimore, MD, May 1995; Chair, Topical Group for X-Rays, Optical Society of America, Technical Council; American Local Executive Committee, 15th Intl. Conf. on Coherent and Nonlinear Optics, St. Petersburg, Russia, July 1995.
University Service
IPST: Policy Committee; Salary Committee; Facilities and Services Committe. EE Ph.D. Qual. Exam Panel; Dissertation Defense Committee.
Recent Publications
Patent
Assistant Professor,
Ph.D., University of California, Berkeley.
Joint Appointment with ISR, NSF Career Award
Research Interests
Dr. Milor’s research interest is in the testing of analog and mixed signal circuits. Because analog and mixed signal testing accounts for a significant portion of final device cost, it is considered one of the most important problems in integrated circuit design by many large companies and the Semiconductor Industry Association. In her work, the use of semiconductor process characterization data and circuit/behavioral simulation has been proposed to reduce the cost of production testing of analog circuits. Algorithms have been developed for optimally ordering tests and for identifying redundant tests, which can be dropped without significant fault coverage loss.
A circuit, in order to be manufacturable, needs to be insensitive to uncontrollable variations in the manufacturing process. In her work, statistical modeling algorithms have been developed for calculating parametric yield. Statistical modeling reduces the computational cost of yield estimation by replacing Monte Carlo simulations with a response surface model. Her work primarily concentrates on constructing nonlinear response surface models for high dimensional functions.
Professional Service
SWE Panel Discussion on Women in Academics; Technical Program Committee, Custom Integrated Circuits Conf., 1996; Panel Session Coordinator, VLSI Test Symp., 1996.
Recent Publications
Professor,
Ph.D., Northwestern University.
NSF Presidential Young Investigator
Research Interests
Dr. Nakajima’s research interests are in the general area of computer software/hardware codesign, VLSI, large-scale computational methods, parallel/distributed computing systems, fault-tolerant computing, and applied graph theory. His current research activities include software/hardware codesign, VLSI system design, VLSI design automation, and large-scale computational methods.
Recent advancement of VLSI CAD tools and reconfigurable VLSI devices has made it possible to develop both software and hardware for application- and algorithm-specific computing systems. Using state-of-the-art CAD tools, including Hardware Description Languages, application-specific RISC processors and DSP chips are designed and fabricated into VLSI chips. Low-power chip design methodologies, in particular, at the algorithmic and architectural levels, are also investigated. Based on a recently established algorithm/architecture-based low-power design methodology, 11,500-gate CMOS DSP chips were designed, fabricated, and successfully tested in the VLSI Design Automation Lab (in collaboration with Dr. Liu). These chips are also of high performance when regular supply voltages are applied.
In the area of VLSI design automation, efficient algorithms are developed for routing and placement for gate arrays, FPGAs, and MCMs. Some of our algorithms have been implemented in CAD tools in Japan, having produced over 500 commercial chips. Development of neural network-based algorithms and integrated design system for algorithm-based low-power DSP chips are also in progress.
In the areas of large-scale computational methods and their parallel computing system design, a new method of solving linear equations has been established. It has been applied in many fields, and various improvements over the traditional methods have been reported, such as speed-up of the SPICE circuit simulator. Parallel and distributed system architectures for hardware implementation of this method are also investigated. The ultimate goals are to build application/algorithm-specific computing hardware systems.
Professional Service
Assoc. Editor, J. Circuits, Sys., and Computers.
University Service
Ph.D. Qual. Exam Panel; General Academic Affairs Committee; Graduate Studies and Research Committee; Computer Committee; MOSIS Subcommittee; Ad Hoc Committee on Graduate Studies Recruitment.
Recent Publications
Professor,
D.Sc., Washington University, St. Louis.
Joint Appointment with ISR
Research Interests
Dr. Narayan’s research interests are in the areas of information and communication theory, performance evaluation issues in hybrid wideband terrestrial and satellte communication networks, and system modeling and identification. Applications include data and video compression, transmitter-receiver designs for communication systems, speech recognition, and switching and capacity assignment in high-speed networks.
His current research activities include the statistical modeling of data and universal data compression. This work, which is at the interface of information theory and statistics, involves an investigation of general models for "real" data and the associated theoretical limits of compressibility, together with the development of finite-state algorithms for compressing the data efficiently and on-line. A related activity concerns a study of the fundamental limits of, as well as efficient schemes for, hierarchical or multi-resolution data/video compression and routing in multicasting applications. The issues of bit allocation and rate control for video compression are also being addressed.
Another activity focuses on design and performance analysis for high-speed terrestrial and satellite networks. This study includes the development of models for multimedia traffic displaying short- and long-range dependencies, and the evaluation of component performance and end-to-end quality of service with applications to buffer engineering and capacity assignment.
University Service
Ad Hoc Search Committee for EE Chair; ISR Executive Committee.
Recent Publications
Professor,
Ph.D., University of California, Berkeley.
IEEE Fellow
Research Interests
Professor Newcomb’s research interests are in the general area of circuit and systems theory with reference to VLSI realizations, especially for neural networks and biomedically related systems.
Much of his current research is oriented toward biologically realistic neural networks, including those with live neurons on silicon chips. Some of this research stems from joint undertakings with colleagues at other institutions. For example, the neurophysiologically oriented neural network PC program SYNETSIM of Dr. D. Hartline at the University of Hawaii has been made user friendly by his research group and is presently being translated from a software to a hardware version. Related research concerns the generation of chaos in biologically realistic artificial neural networks with the intent of being able to develop means to control chaotic activity, such as epilepsy, in biological systems. On the more mathematical side, a functional neural network has been developed which is based upon reproducing kernels in Hilbert space and which can be used to model dynamical systems for nonlinear control, this work being also carried out in conjunction with colleagues at the University of California, Irvine. Applications of developed circuits are made to multiple armed robots and new classes of computers. One of the primary research efforts of his Micro-Systems Laboratory group is associated with self emissions from the ear. Theories for these emissions are under development as well as circuits which can be used to control them and which also lead to new classes of hearing aids.
Professional Service
Neural Networks Council Fellows Committee; Organizing Committee - Neural Networks special session for Asilomar Conf., 1995 and ISCAS’96; Session Chair, SICICI’95, Session TAC3-Neural Networks, July 1995; Asilomar CAS Conf., Session TP4-Neural Networks, Oct.1995; Assoc. Editor, IEEE Trans.Circuits and Systems; Neurocomputing; CSSP Journal. Technical Committees: IEEE CAS Neural Systems, ICARCV’96, Singapore; 1995 IEEE Mediterranean Symp. on Control and Automation, Crete; ICNN’96.
University Service
Ph.D. Qual. Exam Panel; President’s Delegation to South East Asia.
Recent Publications
Professor,
Ph.D., Oregon Graduate Center.
Joint Appointment with IPR,
NSF Presidential Young Investigator
Research Interests
Dr. Orloff’s interests are in the production, focusing, and applications of high brightness ion and electron beams. His research is in field emission ion sources, ion optics, and applications of high resolution focused ion beams.
Dr. Orloff joined the faculty at the University of Maryland in December 1993. In 1994, he was principally involved in the establishment of the Laboratory for Ion Beam Research and Applications. His present work involves studies of high brightness gas phase field ionization sources for possible applications in ion lithography and high resolution ion microscopy. Dr. Orloff is also doing research on novel lenses, including space charge lenses, that can be used to improve the performance of the sort of high resolution focused ion beam systems that are widely used for semiconductor device design and fabrication. With the installation at Maryland in the summer of 1995 of a high performance focused ion beam/scanning electron microscope system, he began research in the area of micro-machining—the direct fabrication of objects at scale of ~10 micrometers. He is also planning work on the study of new classes of electrohydro-dynamic ion sources for possible application in secondary ion mass spectrometry as well as beam induced chemistry.
Professional Service
Advisory Committee, Intl. Symp. on Electron, Ion and Photon Beam Tech.; Advisory Panel on Biological Instrumentation and Resources, National Science Foundation, Fall 1995.
University Service
Senate CORE Committee; Fellowship Committee; Graduate Studies and Research Committee; Editor for Fall 1995 and Spring 1996 EE Connections Newsletter.
Recent Publications
Professor,
Ph.D., Syracuse University.
Research Interests
Dr. Oruç’s research is motivated by a variety of problems which arise in the analysis and design of networks for advanced computer and communication systems. These problems range from lower bound complexity questions for certain types of interconnection structures, such as concentrators, superconcentrators, permuters, generalizers, sorters, and non-blocking networks, to the proofs of their existence as well as their explicit constructions within asymptotical orders of such lower bounds. Our techniques in attacking these problems rely on both deterministic and random computation and communication models.
He is also interested in nurturing synergies between different areas of research on computer and communication systems. In this regard, his recent research concentrated on how to use cyclic permutation networks to compute various scalar and vector computations by exploiting monoid and group isomorphisms between algebraic and permutation groups. This work resulted in a U.S. patent.
The structure of full linear groups of nonsingular matrices to develop a network-based computer for matrix computations is presently being studied.
University Service
Dept. Council; College Council, School of Engineering; Chair, Human Relations and Welfare Committee; Ph.D. Qual. Exam Panel.
Recent Publications
Patent
Professor,
Ph.D., Polytechnic Institute of Brooklyn. Joint Appointments with Physics and ISR, American Physical Society Fellow,
Distinguished University Professor, IEEE Fellow
Research Interests
Professor Ott’s research interests are in chaotic dynamics, fundamental theory of chaotic systems and their application to problems in science and engineering.
Some of his areas of interest where fundamental aspects of chaos have been investigated include: (1) bifurcations of chaotic attractors resulting in sudden changes in the size or character of the attractor; (2) studies of the properties of regions of state space that lead to different solutions (e.g., fractal basin boundaries); (3) the properties of chaotic transients (orbits that display chaotic behavior for a finite time after which they abruptly move off to execute some other type of motion); (4) studies of the fractal and multi-fractal properties of invariant measures on chaotic attractors and other invariant chaotic sets.
Some areas of current interest where chaos theory is applied to problems in science and engineering are the following: (1) control of chaotic dynamical systems (the exponential sensitivity of chaos to small perturbations implies that chaotic systems can be controlled by use of only small controls); (2) use of the symbolic dynamics representation of chaotic orbits for the purposes of communication; (3) application of chaotic dynamics to studies of fluids and plasmas (e.g., the kinematic dynamo problem which addresses the question of why the earth and the sun have magnetic fields).
Professional Service
Editorial Board, Chaos; Editorial Board, Dynamics and Stability of Systems; IEEE Plasma Sci. Human Rights Committee; IEEE Plasma Sci. Employment Center Committee.
University Service
EE: Ward Chair Search Committee; Salary Committee; Facilities Committee; Ph.D. Qual. Exam Panel. Physics APT Committee; Provost’s Advisory Committee on Distinguished University Professors; Engineering College ATP Committee; Engineering College Awards Committee.
Recent Publications
Associate Professor,
Ph.D., Cornell University.
Research Interests
Dr. Papamarcou’s research interests are in the areas of information theory and statistical communications. His current efforts are focused on the optimization of multi-sensor networks for distributed inference and data fusion. Different network configurations involving data collection and processing nodes connected via information links of varying capacity are considered. Algorithms are sought that optimally classify random signals while meeting constraints on complexity, time delay, and communication bandwidth. His approach, which is based on large-sample performance figures for regularized signal sources, yields powerful and insightful tools for optimal distributed inference. The results of his work also underscore fundamental differences in the choice of statistical methods and algorithms between single-sensor and multi-sensor systems.
University Service
EE: Director, Honors Program; Ph.D. Qual. Exam Panel; Ad Hoc Committee on Curriculum Revision; General Academic Affairs Committee; Undergraduate Affairs Committee; EE Faculty Advisor, Cooperative Education Program, College of Engineering.
Recent Publications
Professor,
Ph.D., Mainz University, Germany.
IEEE Fellow,
American Physical Society Fellow
Research Interests
Dr. Reiser’s research interests are in the general area of charged particle beams, in particular the study of fundamental properties of beams and the design of particle accelerators and other devices.
His current research activities are focused on experimental and theoretical investigations of beams with strong space-charge forces and applications, such as high-intensity accelerators (for science, material research, and energy), high-power microwave generators, and free-electron lasers. This work includes the self-consistent modeling of beams, the evolution of beam degradation, known as "emittance growth" due to mismatch, temperature anisotropy, instabilities, and other effects.
The major results of this research over the past two decades have been included in the book Theory and Design of Charged Particle Beams, which was published in the fall of 1994 by Wiley and Sons.
Another experimental and theoretical activity started recently is concerned with the use of H- beams for ion projection lithography (IPL). In a collaborative effort, an H- ion source with very favorable beam characteristics developed at Novosibirsk will be assembled and studied at our test facility in the IPR. IPL is a promising technology for production of future integrated micro-circuits with minimum line width below 0.2 mm.
Professional Service
Organizing Committee, 1997 Particle Accelerator Conf.; Chair, Program Committee for 1997 Particle Accelerator Conf.; Scientific Advisory Board, European Accelerator Conf.; Organizing and Program Committees and Session Chair, 8th ICFA Advanced Beam Dynamics Workshop on Space-Charge Dominated Beams and Application of High Brightness Beams, Bloomington, IN, Oct. 1995; Program Committee, U.S. Particle Accelerator School; APS/DPP: Vice-Chair, Executive Committee; Chair, APS Fellowship Committee; Public Relations Coordinator; APS/DPB Education Committee.
University Service
EE: Promotions and Tenure Committee; Search Committee for EE Chair; IPR Library Committee; Engineering Council; APS/DPB: Outstanding Ph.D. Award Committee.
Recent Publications
Professor,
Ph.D., The Catholic University of America.
Research Interests
Dr. Rhee’s research interests cover the broad area of charged particle beams, beam qualities, pulsed power systems, plasma focus, and pseudospark discharge.
His current research activities are centered around studies on pseudospark discharge. The pseudospark is a fast low-pressure gas discharge between a hollow cathode and a planar anode. Interesting phenomna associated with the discharge include fast spark-like discharge and charged particle emission during the discharge. Such phenomena would find immediate applications in fast switches, high-quality charged particle beam sources, and beam source for material processing. Systematic experimental studies have been carried out for the breakdown voltage characteristic, the electron beam current scaling, energy spectrum of the electron beam, the emittance and brightness of the electron beam, and the post acceleration of the electron beam. Interesting experimental results obtained are expressed in empirical formula that would be useful in understanding further the pseudospark phenomena. Currently, study of modeling the pseudospark breakdown is underway based on the measured breakdown voltage characteristic that distinctively differs from Paschen’s law.
Professional Service
Lectured in Korea: Seoul National Univ., Advanced Inst. of Sci. and Tech. in Tejun, and Pohang Univ. of Sci. and Tech.
University Service
Computer Committee; Ph.D. Qual. Exam Panel; Coordinator, EE Dept. World Wide Web page.
Recent Publications
Associate Professor,
Ph.D., Stanford University.
Joint Appointment with ISR, IEEE Senior Member
Research Interests
Dr. Shamma’s research over the last 15 years has dealt with issues in computational neuroscience and the development of microsensor systems for experimental research and neural prostheses. Primary focus has been on uncovering the computational principles underlying the processing and recognition of complex sounds (speech and music) in the auditory system, and the relationship between auditory and visual processing. Other contributions include the development of photolithographic microelectrode arrays for recording and stimulation of neural signals, VLSI implementations of auditory processing algorithms, and development of algorithms for the detection, classification, and analysis of neural activity from multiple simultaneous sources.
University Service
ISR Education Committee.
Recent Publications
Professor,
Ph.D., Harvard University.
Joint Appointment with ISR,
NSF Presidential Young Investigator
Research Interests
Dr. Shayman’s research interests are in the general area of discrete event systems, control theory, and applications to the management of communication networks.
Discrete event systems (DES) are systems in which the variables take on discrete values which change asynchronously at discrete times. Many engineering systems can be represented by DES’s; examples include communication networks, manufacturing systems, and transportation systems. Within the field of DES’s, he is particularly interested in the supervisory control of such systems. He has been involved in the development of a new framework for supervisory control which can be used to design controllers for reactive systems as well as nondeterministic plants. By encapsulating sensor and actuator capabilities with logic to form so-called process objects, and using a single type of binary operator called masked composition to interconnect process objects, it shows promise of providing a foundation for an object-oriented approach to discrete event control.
Within network management, he is primarily interested in fault management. The goal is to develop network management systems that can automatically detect, isolate, and mitigate various faults that occur in a large communication network. The project uses rule-based expert systems and neural networks as tools. Dr. Shayman is also interested in mobility management for wireless networks.
Professional Service
Chair, Technical Committee on Control Theory, IEEE Control Systems Soc.
University Service
Director, M.S. in Systems Engineering (MSSE) Program, ISR; also responsible for administration of Systems Engineering Option for the Professional Master of Engineering Program and continuing development of proposed Ph.D. in Systems Engineering Program; Executive Committee, ISR. EE: Undergraduate Affairs Committee; Human Relations and Welfare Committee; Representative Campus Senate.
Recent Publications
Associate Professor,
Ph.D., Notre Dame University.
Research Interests
Dr. Silio’s research interests are in the area of computer network architecture and performance evaluation. Multiprocessor interconnections using a fiber optic multiple access ring network with a completely distributed, fault tolerant control mechanism are being investigated. The investigation includes Monte Carlo discrete event simulation and analytical modeling to predict performance in varying configurations and to make performance comparisons with other networks. Designs for implementation using fiber optic links and a double ring fault-tolerant configuration in local area computer communication networks are in progress. The reliability of fiber optic ring networks also is being investigated. Work to date has concentrated on obtaining closed form expressions with which to predict reliability of the fault-tolerant ring network configurations proposed in the literature under various measures of reliability. FDDI network structures are of particular interest.
Professional Service
Program Co-chair, 26th Intl. Symp. on Multiple-Valued Logic, Santiago de Compostela, Spain, May 1996; Editorial Board, Multiple-Valued Logic, an Intl. J.; Executive sub-committee, IEEE Computer Society Technical Committee on Multiple-Valued Logic.
University Service
Chief Advisor, Maryland Beta Chapter, Tau Beta Pi Assn.; EE: Ph.D. Qual. Exam Panel; Graduate Studies and Research Committee.
Recent Publications
Assistant Professor,
Ph.D., Carnegie Mellon University.
Joint Appointment with UMIACS,
Faculty Affiliate with ISR
Research Interests
Dr. Stewart’s research interests lie in the area of software engineering for real-time systems. The objective of his research is to develop techniques to improve the quality of real-time systems while reducing development time and cost. The approach is to develop the software models, operating system services, and computer-aided software engineering (CASE) tools required to design dynamically reconfigurable and reusable component-based software. These models, services, and tools comprehensively form The Chimera Methodology, which has been successfully applied to robotics and multi-sensor systems. Other application areas of interest include embedded systems, signal processing, multimedia, process control, virtual laboratories, generic factories, and rapidly deployable systems.
His current research activities are focused on developing a Real-Time Co-Operating System (RTCOS) for multiprocessor workstations. This project involves merging operating system services and tools required to support the Chimera Methodology with the new multiprocessor and real-time features of Solaris 2.x. The software architecture of the proposed RTCOS is analogous to a hardware architecture that involves a main general-purpose processor and a floating point coprocessor. A visual programming user interface based on a software assembly paradigm provides an environment for rapid development of real-time applications.
Additional projects related to his interests include advanced soft real-time scheduling, real-time performance monitoring and debugging, real-time communication protocols for distributed shared memory and networked systems, and extending the Chimera Methodology to support fault-tolerance.
Professional Service
Program Committee for High Assurance Systems Engr. Workshop.
University Service
Department Council; Faculty Search Committee; Computer and Facilities Committee.
Recent Publications
Professor,
Ph.D., University of Michigan.
Research Interests
Dr. Striffler’s general area of interest within the plasma physics field involves intense relativistic electron beams and their uses. Specifically, he has been involved in the theoretical analysis of beam transport properties, the design and understanding of collective ion acceleration systems, the design and development of high-power microwave and millimeter wave sources, and the analysis of high-power switches as a source of high quality electron beams.
Most recently, his research has included the upgrading of a state-of-the-art diode design code to include all self-fields. To date, in various design codes, the self-electric fields have been included but the self-magnetic fields have been neglected. In intense beam diodes that involve substantial magnetic compression, these self-magnetic fields appear to have a substantial effect on the properties of the beam. In addition, low pressure gas breakdown behavior in a hollow cathode configuration has resulted in fast high-power switches and a source of high quality electron beams. This so-called pseudospark discharge has been under investigation as an electron source, and he has been involved with numerical simulation studies of this system. Finally, he has been interested in RF-plasma interaction where surface wave physics dominates. Applications of this latter study includes heating of plasmas by RF sources, and the propagation of RF through the atmosphere. Various nonlinear processes occur in these systems and lead to radiation generation that can serve as a signature of the specific process that is occurring.
University Service
"Advise Five" Program in Division of Letters and Sciences; General Research Board Committee. EE: General Academic Affairs Committee; Graduate Studies and Research Committee; Assoc. Chair for Facilities and Services; Computer Committee; Facilities and Services Committee. Engineering Teaching and Learning Committee; Engineering APT Committee; Engineering Service Award Committee; Director of the Science, Technology, and Society Program in the College Park Scholars Programs.
Assistant Professor,
University of Maryland, College Park.
Research Interests
Dr. Tassiulas’ research interests are in the general area of communications and systems with emphasis on: wireless access networks, progagation-based cell planning and dimensioning, channel and power control, digital signaling in a cochannel interference environment; multihop radio networks, transmission scheduling and packet routing, time-varying topologies, satellite networks, power efficient management; high-speed networks and ATM, architectures, control and management, multimedia traffic modeling, quality of service guarantees for multimedia traffic; multiuser communications and information theory, optimization and control of stochastic systems, distributed systems and algorithms.
Recent Publications
Professor,
Ph.D., New Mexico State University.
IEEE Life Fellow, American Society for Laser Medicine and Surgery Fellow
Research Interests
Dr. Taylor’s research interests lie in applications of microwave radiation in medicine, biology, and industry. Particular projects have included the invention and design of invasive applicators for cancer therapy (the needle radiator which is in wide use) and the invention and design of microwave coagulating devices for surgical use in liver and spleen surgery (successfully tested in human trials). Other work with medical applications has included the design of miniature contact radiators for treatment of surface cancers. Other theoretical and experimental studies completed have involved the use of microwaves in industrial diagnostic applications, such as a tool for determining the moisturization of human skin by cosmetic moisturization products, and in determining the thickness of fat in live cattle. A number of purely theoretical studies have been completed which involve the possible applications of special wave types and wave generators in producing microwave beam fields which can penetrate deeply into tissue for possible medical applications. At this time, work is concentrated on the measurement of the dielectric permittivity of the components of bone at low microwave frequencies, a critical item in the assessment of the penetration of cellular telephone radiation into the human cortex.
University Service
College of Engineering "Hall of Fame" Committee.
Recent Publications
L. S. Taylor, "Microwave Surgery," chapter 5 in New Frontiers in Medical Device Technology, A. Rosen and H. D. Rosen, eds., John Wiley & Sons, New York, NY, 1995.
Professor,
Ph.D., University of California, Berkeley. Permanent Joint Appointment with ISR,
NSF Presidential Young Investigator
Research Interests
Dr. Tits’ main research interests lie in various aspects of optimization-based system design and robust control. The former include theoretical questions in numerical methods for optimization, novel ideas and software for interactive optimization-based design, and application of the above to the design of electrical, chemical, and mechanical systems. Current projects include the development of a fast feasible algorithm for semi-infinite optimization and the development of graphical tools for exploration of design trade-offs. His recent work in robust control has dealt with both parametric and dynamic uncertainty, including contributions to the computation of the structured singular value and of the real stability radius, and to robust pole assignment by state feedback.
Professional Service
Assoc. Editor-At-Large, IEEE Trans. Automatic Control; Assoc. Editor, Systems and Control Lett., Assoc. Editor, Automatica (IFAC Journal); Intl. Program Committee for the IFIP Conf. on Modeling and Optimization, Prague, Czech Republic, July 1995; Intl. Program Committee for the 4th European Control Conf., Brussels, Belgium, July 1997; Intl. Program Committee for the IEEE Intl. Symp. on Computer-Aided Control System Design, Dearborn, MI, Sept.1996.
University Service
EE: Assoc. Chair for Graduate Studies and Research; ex officio member of the Graduate Studies and Research Committee.
Recent Publications
Associate Professor,
Ph.D., Princeton University.
Research Interests
Dr. Tretter’s research interests are in the areas of communication systems and theory, digital signal processing, and error correcting codes. More specifically, he has been working on developing DSP algorithms to use in wireline modems. These include techniques for adaptive echo cancellation, adaptive equalization, carrier recovery and tracking methods, nonlinear precoding techniques, and trellis coding methods combined with shell mapping.
He is also supervising the use of the DSP equipment and software donated to the University of Maryland by Texas Instruments when they designated us as an Elite DSP Laboratory. He is helping various teams and individuals with the details of how to use these resources.
University Service
EE Coordinator for the Professional Master of Engineering Program; Director of Cross-Disciplinary MS in Telecommunications Program; General Academic Affairs Committee; Undergraduate Affairs Committee; Human Relations and Welfare Committee.
Recent Publications
Professor,
Ph.D., State University of New York, Brooklyn.
Joint Appointment with Physics,
American Physical Society Fellow
Research Interests
Dr. Venkatesan’s research program focuses on the science and applications of thin film based multi-component materials of technological interest. Examples are high temperature superconducting copper oxides, colossal magneto-resistive manganates, ferroelectric oxides for high dielectric constant materials and so on. The program includes growth of epitaxial thin films on a variety of substrates, characterization of the composition, structure and the electronic properties of these films and fabrication of novel devices based on the unusual properties of these layers.
Some of the active projects are superconducting electric field effect transistors, tunable high Tc microwave filters, superlattices of high temperature superconductors with tailored properties, colossal magneto-resistive transducers, CMOS structures on wide band gap materials such as SiC. Emphasis is on the physics of charge transfer in the cuprates, vortex dynamics, and dynamics of transport in a spin correlated system.
The research programs emphasize training in the growth and characterization of thin films of complex materials, transport measurements, device fabrication via different lithographic techniques and device characterization. Understanding of the underlying physical mechanisms behind the fascinating properties of these materials is a common thread connecting the various projects.
The facilities are state of the art with seven pulsed laser film deposition systems, Rutherford backscattering systems and X-ray diffractometers, atomic force microscopes, a number of superconducting magnets for transport measurements, and clean room for device processing.
Professional Service
Elected Advisor Industrial Physicist; publication of Amer. Inst. of Physics.
Recent Publications
Professor,
D.S., Technion - Israel.
Joint Appointment with UMIACS, Fellow, ACM
Research Interests
Dr. Vishkin’s research interests are in the area of parallel algorithms and parallel computing. The main concrete motivating question guiding his research has been "how to think in parallel".
This includes search for innovative paradigms and methodologies for the development of parallel algorithms. Work that he has done with this motivation is represented in textbooks on the design of algorithms. He is also interested in contributing to the development and understanding of underlying principles for the evolving generation of parallel computer systems.
Professional Service
General Chair, 4th Workshop on Parallel Algorithms, 2nd Federated Computing Research Conf., Phila., May 1996; Organizer, Project for Suggesting Computer Science Agenda(s) for High-Performance Computing. Program Committees: 22nd Colloquium on Automata, Languages and Programming, Hungary, July 1995; Frontiers ’95, the 5th Symp. on the Frontiers of Massively Parallel Computation, Feb. 1995; 9th IEEE Intl. Parallel Processing Symp., 1995. Conf. Co-Chair, 3rd Israel Symp. on Theory of Computing and Systems, Tel Aviv, Israel, Jan. 1995. Editorial Board: Parallel Processing Lett., J. of Algorithms.
University Service
UMIACS APT Committee.
Recent Publications
Associate Professor,
Ph.D., Princeton University.
Research Interests
Dr. Yang’s research interests are in the general area of semiconductors, including the physics, fabrication techniques, and their devices applications. One project is to realize world’s smallest transistors with channel length of the order of 10 nm. The operating principle of these new transistors is based on quantum mechanical tunneling and new electron transport phenomena in reduced dimensions. The most significant feature of these new transistors is that they are much smaller than the ultimate scaling limit of conventional MOSFETs. Another area is to study the transport and optical properties of semiconductor quantum dots, with emphasis on the role of hetero-interfaces and surfaces.
University Service
General Academic Affairs Committee; Graduate Studies and Research Committee.
Recent Publications
Professor,
Ph.D., University of California, Berkeley. IEEE Fellow
Research Interests
Dr. Zaki’s research interests are in the areas of modeling, simulation, and Computer Aided Design (CAD) of microwave and millimeter wave components and subsystems. Her current research activities are in the development of precise and efficient numerical techniques for modeling complex guiding and resonant electromagnetic structures. Mode matching techniques for the determination of generalized scattering matrices of structures that cannot be described by a single coordinate system (e.g., cylindrical obstacles in rectangular enclosures) are being used to affect reduction of two orders of magnitude in computation times compared to direct numerical solutions of Maxwell’s equations (e.g., using finite element or finite difference). As a result, CAD tools for direct optimization of practical structures such as filters, multiplexers, power dividers, etc. are feasible on PC’s or work stations that require seconds or a few minutes.
The work is being applied for development of several practical systems components, including (1) filter networks with extremely demanding characteristics in the PCN and PCS wireless networks in the newly allocated frequency spectrum; coaxial, combine, and dielectric resonator structures are used for the realization of miniature high quality filters; (2) tunable filters using planar structures in superconducting materials; tunability is achieved by either magnetic (Yig) materials or by varacter voltage controlled diodes; (3) ultra low noise oscillators using dielectric resonators or cooled sapphire resonators; (4) miniature filter banks realized using Low Temperature Cofired Ceramics (LTCC) for application in communications and advanced radar systems.
Professional Service
Chair, IEEE-MTT-S Subcommittee on Dielectric Resonators and Waveguide; Technical Program Committee for 1995 and 1996 IEEE MTT-S Intl. Microwave Symp.; Technical Program Committee for 1995/96 IEEE Antenna and Propagation Society.
University Service
EE: Graduate Studies Committee; Diversity Programs Committee; Recruitment Committee. Panel Discussion, Society of Women Engineers, Women in Academia, Mar. 1995.
Recent Publications
Patents
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