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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： M. O'Hara X. Yu N. Mehdi C. Schwartz D. Wu B. Avitall B. He Bioeng. Program Illinois Univ. Chicago IL USA Department of Electrical Engineering and Computer Science University of Illinois Chicago Bioengineering Program University of Illinois Chicago Department of Medicine University of Illinois Chicago

We investigated the feasibility of obtaining body surface Laplacian maps (BSLMs) from unipolar electrocardiographic recordings in humans. The overall pattern of the BSLMs during ventricular depolarization is reproducible for subjects examined and for multiple sets of maps within a single subject. Right and left ventricular activities are well resolved in the BSLMs over the anterior chest as compared with body surface potential maps (BSPMs). Our experimental results demonstrate the feasibility of performing body surface Laplacian electrocardiographic mapping from potential recordings. The effects of measurement noise and electrode position uncertainty on the Laplacian derivation were also evaluated by computer simulation.

关键词： Laplace equations Humans Electrodes Bioelectric phenomena Electric potential computer simulation Position measurement Noise measurement Signal processing Gaussian noise

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A Model For The Relative Environmental Stability Of A Series Of Polyimide Capacitance Humidity Sensors

A Model For The Relative Environmental Stability Of A Series...

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International Conference on Solid State Sensors and Actuators (TRANSDUCERS)

作者： A.R.K. Ralston C.F. Klein P.E. Thomas D.D. Denton Central Research Johnson Controls Inc. Milwaukee WI USA Materials Science Program Department of Electrical and Computer Engineering and Department of Chemistry University of Wisconsin Madison Madison WI USA

A capacitance humidity sensor is used as a test de- vice to characterize the performance of thirteen polyimide films in relative humidity sensing applications. This sensor has a multilayer, free-standing film construction. It consists of a humidity sensitive polyinfide dielectric core and conductive layers consisting of carbon filled polysul- fone on each side of the polyimide film to form a capacitor. Thirteen polyimide films, including commercial polyimides and films of novel chemistry, are investigated to determine the long term stability of sensors using the films exposed to 85'C/85% RH for a total of 28 days. Differences in film chemistry are used to interpret trends in the environmental stability of the films.

关键词： Stability Polyimides Capacitance Humidity Sensor phenomena and characterization Chemical sensors Chemistry Capacitive sensors Aging Conductive films

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Microemboli characterization by determination of Legendre coefficients of phase function

Microemboli characterization by determination of Legendre co...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Jungkuk Kim J.C. Lin L.O. Reynolds BioEngineering Program University of Illinois Chicago Chicago IL USA Electrical Engineering and Computer Science Department University of Illinois Chicago Chicago IL USA University of Illinois Chicago Chicago IL USA

The characterization of microemboli located in whole blood is attempted by determining the Legendre coefficients of phase function from the scattered light distribution around the medium. In the radiative transport equation, a microembolus is represented as a secondary source and assumed to have a spherical form and the first order transport approximate solution of the equation is used to describe the scattered intensity distribution. After the scattered intensities are determined at the surfaces of the medium, the orthogonal property of Legendre polynomial is used to extract the coefficients out of the intensities. From the obtained coefficients, the size and complex index of refraction of microemboli are determined.

关键词： Particle scattering Red blood cells Laboratories Cells (biology) Equations electrical capacitance tomography Polynomials Position measurement computer simulation Slabs

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Performance of CDMA smart antenna systems

Performance of CDMA smart antenna systems

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Asilomar Conference on Signals, Systems & computers

作者： M. Torlak Guanghan Xu Department of Electrical & Computer Engineering University of Texas Austin Austin TX USA Naval Research under Grant Joint Services Electronics Program Bell Technology Resources Inc. Motorola USA

Preliminary radio frequency (RF) field experiments were conducted to evaluate the performance of smart antenna systems for code-division multiple access (CDMA) systems. Besides conventional multipath fading problems, CDMA schemes are subject to near-far problems. The IS-95 CDMA system uses a 1/3 convolutional encoder and an interleaver to mitigate the fading problem and uses feedback power control schemes to equalize the powers of all the uplink co-channel signals. We evaluate the performance of the IS-95 standard implemented on a smart antenna system in a slow-fading environment. In particular, we evaluate the effects of imprecise power control, convolutional coding, and different beamforming techniques for a CDMA smart antenna system. Our results show that the smart antennas are not so sensitive to imperfect power control and that the optimal (Wiener) beamforming technique outperforms the simple beamforming approach. The most interesting result is that the effect of convolutional coding is not so significant for a smart antenna system than for an single antenna system. Based on our limited experimental results, we found that the 3 times bandwidth dedicated to the 1/3 convolutional encoding is better used to increase the spreading factor in a CDMA smart antenna system, leading to reduced cost and perhaps better performance.

关键词： Multiaccess communication Convolutional codes Convolution Power control Array signal processing Radio frequency Fading Feedback Bandwidth Encoding

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Ultrasonic displacement and strain imaging of coronary arteries with a catheter array

Ultrasonic displacement and strain imaging of coronary arter...

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IEEE Symposium (IUS) Ultrasonics

作者： B.M. Shapo J.R. Crowe A.R. Skovoroda M.J. Eberle N.A. Cohn M. O'Donnell Electrical Engineering and Computer Science Department and Bioengineerin Program University of Michigan Ann Arbor MI USA Institute of Mathematical Problems of Biology Russian Academy of Science Pushchino Russia Endosonics Corporation Rancho Cordova CA USA

Tissue elasticity can be estimated from displacement and strain images acquired under controlled deformation. We extend this approach for coronary arteries, deformed and imaged by an integrated angioplasty balloon and ultrasonic imaging probe. Because the lumen cross section of a severely occluded artery is generally not circular, we have also developed a technique to perform all motion computations in the reference frame of the lumen's geometric center. This coordinate system is independent of the imaging catheter, and consequently referencing to this frame removes artifacts associated with probe motion within the balloon during deformation. Displacements and strains estimated by phase-sensitive correlation-based speckle tracking were used to distinguish arterial plaques in simulated coronary arteries of differing elastic moduli: hard, soft, and homogenous. We have also applied these methods to images of a homogeneous gelatin phantom collected with the integrated probe. The spatial dependence of these quantities shows good agreement with theoretically predicted values.

关键词： Capacitive sensors Ultrasonic imaging Arteries Probes Elasticity Displacement control Strain control Angioplasty Catheters Phase estimation

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Gas desorption from FEA-phosphor screen pairs

Gas desorption from FEA-phosphor screen pairs

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IEEE International Conference on Vacuum Microelectronics (IVMC)

作者： M.E. Malinowski K.D. Stewart D.A.A. Ohlberg T.E. Felter A.G. Chakhovskoi C. Hunt L.E. Shea B.E. Russ J.B. Talbot J. McKittrick Sandia National Laboratories Livermore CA USA Department of Electrical and Computer Engineering University of California Davis CA USA Materials Science Program and Department of AMES University of California San Diego La Jolla CA USA

Gas desorption from a field emitter array (FEA) cathode and phosphor screen anode in a flat panel display must be controlled so that outgassing products produced during display operation do not change cathode electron emission and degrade display performance and uniformity. In order to help understand such desorption processes and to help define pumping requirements in FEA displays, we have determined the major species outgassing from two phosphor screen-FEA cathode systems. The screens were made from YAG:Cr and ZnGa/sub 2/O/sub 4/, candidate materials for use as low voltage phosphors. The YAG:Cr phosphor screen has spectral output primarily in the red, the ZnGa/sub 2/O/sub 4/, in the blue. Outgassing products were measured outside the line-of-sight of both the FEA and phosphor screens. Therefore, if the FEA-screen pairs studied were in a flat panel display, the products detected would be those pumped by appendage pumps mounted on the flat panel. In the current study, we do not measure the source of the products (FEA or screen).

关键词： Phosphors Flat panel displays Field emitter arrays Cathodes Current measurement Vacuum systems Anodes Glass Indium tin oxide Gases

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PARALLEL AND DISTRIBUTED TLM COMPUTATION WITH SIGNAL-PROCESSING FOR ELECTROMAGNETIC-FIELD MODELING

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INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 1995年第3-4期8卷 169-185页

作者： SO, PPM ESWARAPPA, C HOEFER, WJR NSERC/MPR Teltech Research Chair in RF Engineering Department of Electrical and Computer Engineering University of Victoria Victoria British Columbia V8W 3P6 Canada Poman So received his B.Sc. degree in computer science and physics from the University of Toronto Toronto Onatario Canada in 1985. He obtained his B.A. Sc. and M.A.Sc. degrees in electrical engineering (summa cum laude) from the University of Ottawa Ottawa Ontario Canada in 1987 and 1989 respectively. Mr So was a research engineer in the University of Ottawa from January 1989 to October 1991 his research interests included CAD techniques of microwave circuits and numerical methods for electromagnetic wave modelling. He specialized in the development of electromagnetic engineering CAD software and successfully implemented a number of electromagnetic wave simulators based on the two-dimensional and three-dimensional transmission-line matrix methods. From August 1990 to February 1991 he accompanied Professor W. J. R. Hoefer to Rome Italy and Sophia Antiopolas France. During that time he implemented a parallel version of the 3D-TLM simulator for the CM-2 Connection Machine using C-Star and X Windows Library. He is a research engineer and a Ph.D. student at the University of Victoria Victoria British Columbia Canada. He ported the 2D- and 3D-TLM simulators to DECmpp 1200 massively parallel computer using MPL C and C++. He also combined OSA90/hope a commercially available microwave CAD program with a 2D-TLM simulation module for geometry optimization using the Datapipe technique of OSA90/hope. Recently he has developed a distributed client-server computing technique for the TLM method this technique could accelerate the TLM simulation by more than an order of magnitude. Channabasappa Eswarappa received the M.Tech. degree in electrical engineering from the Indian Institute of Technology Kanpur India in 1983 and Ph. D. degree from the University of Ottawa Canada in 1990. He worked as an Assistant Executive Engineer and later as

This paper describes the implementation of transmission-line matrix (TLM) method algorithms on a massively parallel computer (DECmpp 12000), the technique of distributed computing in the UNIX environment, and the combination of TLM analysis with Prony's method as well as with autoregressive moving average (ARMA) digital signal processing for electromagnetic field modelling. By combining these advanced computation techniques, typical electromagnetic field modelling of microwave structures by TLM analysis can be accelerated by a few orders of magnitude.

关键词： Mathematical models

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Synthetic phased array imaging of coronary arteries with an intraluminal array

Synthetic phased array imaging of coronary arteries with an ...

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IEEE Symposium (IUS) Ultrasonics

作者： M. O'Donnell M.J. Eberle D.N. Stephens J.L. Litzza K. San Vicente B.M. Shapo Dept. of Electr. Eng. & Comput. Sci. Michigan Univ. Ann Arbor MI USA Endosonics Corporation Rancho Cordova CA USA Electrical Engineering and Computer Science Department and Bioengineering Program University of Michigan Ann Arbor MI USA

Previous synthetic array methods for intraluminal imaging of coronary arteries have been greatly extended. First, a 64 element, high efficiency, ceramic piezoelectric, array transducer operating at 20 MHz has been constructed. The array is mounted on the surface of a 1.2 mm diameter catheter appropriate for coronary artery applications. Second, integrated into the catheter tip is a custom analog chip set permitting complete data capture from the array. That is, on each firing any combination of array elements can be selected independently as transmitter or receiver. Using data acquired in this way, a complete phased array aperture (i.e. independent transmit and receive apertures) can be reconstructed. To create real-time images, a beam former based on a custom application specific integrated circuit (ASIC) has been designed and built. Beam forming coefficients were derived using an optimal filtering approach accounting for the circular geometry of the array.

关键词： Phased arrays Arteries Catheters Apertures Application specific integrated circuits Ceramics Piezoelectric transducers Transmitters Image reconstruction Filtering

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A DISTRIBUTED MEDIA ACCESS PROTOCOL FOR PACKET RADIO NETWORKS AND PERFORMANCE ANALYSIS .2. NETWORK SET-UP TIME AND DATA RATE

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 1995年第1期8卷 49-63页

作者： POND, LC LI, VOK Communication Sciences Electrical Engineering Systems University of Southern California Los Angeles CA 90089-2565 U.S.A. Lawrence C. Pond received the M.Sc. and Ph.D. degrees in electrical engineering from the University of Southern California in 1983 and 1990 respectively. Dr. Pond is currently a scientist at Hughes Space and Communications Company having joined in 1980. He has worked in the fields of communication system design mobile communication network and spacecraft payload design. He is currently working on the development of satellite-based ATM transport and switching architectures for BISDN and Defense Information System Network amlications. Dr. Pond is a member of IEEE. Victor O. K. Li was born in Hong Kong in 1954. He received his SB SM and Sc.D. degrees in Electrical Engineering and Computer Science from the Massachusetts Institute of Technology Cambridge Massachusetts in 1977 1979 and 1981 respectively. Since February 1981 he has been with the University of Southern California (USC) LOS Angeles California where he is Professor of Electrical Engineering and Director of the USC Communication Sciences Institute. He has published 150 technical papers and has lectured and consulted extensively around the world. His research interests include high-speed communication networks personal communication networks intelligent networks distributed databases queueing theory graph theory and applied probability. Dr. Li is very active in the Institute of Electrical and Electronic Engineers (IEEE) having been a member of the Computer Communications Technical Committee since 1983 and having served as Chairman from 1987–1989. He served as Chairman of the Los Angeles Chapter of the IEEE Information Theory Group from 1983–1985. He is the Steering Committee Chair of the International Conference on Computer Communications and Networks (IC3 N) General Chair of the 1st Annual IC3N held in San Diego California in June 1992 General Chair and Technical Program Chair of the 4th IEEE Workshop on Comp

In this, the second part of a two-part paper, the required time for establishing a mobile packet radio network using the virtual circuit and time division multiple access protocol developed in Part 1 is analysed. Tools are developed to determine the virtual circuit and network set-up times in terms of the channel bandwidth allocated to establish and maintain the network. The tools are then extended to include the effects of user mobility. Then these results are combined with the network capacity results of Part 1 to analyse the trade-off between the data rate and set-up time of the network. Next a hierarchical architecture is proposed and the network data rate versus set-up time trade-off of this architecture is analysed using these tools. This architecture is shown to both provide a higher data rate and establish faster than flat networks of the same number of nodes.

关键词： PACKET RADIO NETWORK EPLRS DISTRIBUTED NETWORK TDMA VIRTUAL CIRCUITS MULTIHOP NETWORK BOUNDED DELAY MOBILITY NETWORK SET-UP TIME HIERARCHICAL NETWORK NETWORK DATA RATE

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Windows computer laboratory as a tutorial for undergraduate electromagnetics

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computer Applications in engineering Education 1995年第3期3卷 183-183页

作者： McCulloch, J. Keddy, W.A. Stuchly, M.A. University of Victoria Department of Electrical and Computer Engineering University of Victoria Victoria British Columbia Canada Janet McCulloch:is a native of Toronto Canada where she briefly attended both York University and the University of Toronto before she set off on a year-long adventure through the Middle East and North Africa. When she returned to Canada she relocated to California. She spent a number of years living both in Los Angeles and coastal Northern California interspersed with several extended trips through the United States Mexico and Central America. Ms. McCulloch moved to Victoria British Columbia in 1989 and a year later registered in the cooperative education program in Electrical Engineering at the University of Victoria. She is presently in the fifth and final year of the program and has her sights set on graduate school. Besides the work described in this article she has been very much involved in the use of technology to assist in the delivery of curriculum at the senior secondary level. She lives on a country property a half-hour from the University with her husband her horse and three cats. W. Alfred Keddy:is an applications programmer/analyst for the Department of Electrical and Computer Engineering at the University of Victoria. He received a BEng (1988) in Electrical Engineering and an MASc (1994) from the University of Victoria. His research interests include distributed systems image processing local area networks VLSI and DSP system design for computation and communication and human–computer interface design. Maria A. Stuchly:received an MSc in Electrical Engineering in 1962 from Warsaw Technical University and a PhD in Electrical Engineering from the Polish Academy of Sciences in 1970. Between the years of 1962 and 1970 she was with the Warsaw Technical University an Institute of the Polish Academy of Sciences. After immigrating to Canada during 1970 her first position was with the University of Manitoba. In 1976 she became employed by the Bureau of Radi

Contents and implementation of a computer laboratory for undergraduate electromagnetics are described. The laboratory consists of four 3-hour sessions covering vector calculus, Maxwell's equations (integral and differential forms), wave propagation in materials, and wave behavior at planar interfaces. Each session contains theory (in the Help file), animations (where relevant) and a quiz. The program runs on IBM compatible 486-based PCs in a Windows environment and uses the Borland C ++ 4.0 compiler.

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