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OPTIMUM FREQUENCY REUSE IN MOBILE TELEPHONY SYSTEMS

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 1995年第3期8卷 185-190页

作者： KAZANTZAKIS, MG DEMESTICHAS, PP ANAGNOSTOU, ME National Technical University of Athens Computer Science Division Department of Electrical and Computer Engineering Heroon Polytechneiou 9 Zografou Athens 15773 Greece Michael G. Kazantzakii was born in Athens Greece in 1962. He received both the Diploma and Ph.D. Degree from the Electrical Engineering Department of the National Technical University of Athens in 1986 and 1992 respectively. During the period 1992–1993 he was a member of the Staff of the Hellenic Navy Research Centre working in the area of underwater acoustics. Since 1994 he has been a researcher at the National Technical University of Athens Department of Electrical Engineering and Computer Science Telecommunications Laboratory. His interests include data mobile and integrated services networks. Panagiotis P. Demestichas was born in Athens Greece in 1967. He received the Diploma in electrical engineering from the National Technical University of Athens (NTUA) Athens in 1993. At present he is a research assistant at NTUA working towards his Ph.D. dissertation. He participated in the BRITE/EURAM-EURATN and in the RACE-TOMQAT and MONET projects. His research interests are in the areas of broadband and mobile networks queueing theory algorithms and complexity theory. He is a Member of the Technical Chamber of Greece. Miltiades E. Anagnostou was born in Athens in 1958. He received the Electrical Engineers Diploma from the National Technical University of Athens (NTUA) in 1981. During the period 1981–1987 he was a teaching assistant at NTUA. In 1987 he received his Ph.D. in the area of computer networks. In 1987–1989 he served the Greek army in the Air Force Research and Development Center. In 1989–1991 he was a Lecturer and since 1991 he has been an Assistant Professor in the Computer Science Division Department of Electrical and Computer Engineering of the NTUA. He teaches courses on modern telecommunications formal specification of protocols stochastic processes and queueing theory. Since 1981 Dr. Anagnostou has been involved

The reason why cellular mobile telephony systems exist is that they allow frequency reuse. Dynamic allocation algorithms improve the network efficiency and the service quality. Dynamic allocation is closely related to the following instantaneous allocation problem: given a number of channels (frequencies), a cell structure and the number of calls to be accommodated in each cell, find the optimum allocation of channels to cells subject to restrictions concerning the distance of cells, where the same frequency can be reused. In this paper we formulate and solve this problem by showing that it can be reduced to a 0-1 programming problem. Finally we present results, and draw subsequent conclusions.

关键词： MOBILE TELEPHONY FREQUENCY ALLOCATION UMTS

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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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Electronic classroom assessment techniques: Assessment beyond the classroom in a networked environment

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Assessment Update 1995年第6期7卷

作者： Anita Gandolfo Curtis A. Carver Professor of English and director of the Center for Teaching Excellence at the United States Military Academy West Point New York Assistant professor in the Department of Electrical Engineering and Computer Science at the United States Military Academy

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Steady‐state security evaluation of electrical power systems by means of artificial neural network

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European Transactions on Electrical Power 1995年第2期5卷 91-97页

作者： Chiodo, E. Menniti, D. Testa, A. Picardi, C. Elio Chiodo (1959) received the degree in Electronics Engineering in 1985 and the Ph.D. degree in Computational Statistics both from the University of Naplefltaly. He is a Researcher at the Department of Electrical Engineering of the University of Naples and a member of the Italian Statistical Society. His areas of interest include probabilistic methods applied to electric power systems analysis. (University of Naples Fedrrico 11. Electrical Engineering Dept.via Claudio 21 1-80125 Naplefltaly T +3981/7683226 Fax+3981/2396897) Daniele Menniti (1958) received the degree in Electrical Engineering from the University of Calabria. Cosenzataly and the Ph.D. degree in Electrical Engineering from the University of NapleslItaly in 1984 and 1989 respectively. He is a researcher at the Electronic. Computer and Systems Science Department of the University of Calabria. Italy. Hiscurrent research interests concern electric power system analysis real-time control and automation. (University of Calabria Electronic Computer and Systems Science Dep. Arcavacataji Rende (CS). 1-87036 CosenzdItaly T +39984/494707. Fax +39984/4947 13) Alfredo Testa (1950) received the degree in Electrical Engineering from the University of Naples/Italy in 1975. He is an Associate Professor in Electrical Power Systems at the Department of Electrical Engineering of the University of Naples. He is engaged in researches on electrical power systems reliability and harmonic analysis. (University of Naples Federico 11. Electrical Engineering Dep. via Claudio '2 1 1-80 I25 NapleslItaly T + 39 8 I/7 68 3'2 11. Fax+3981/2396897) Ciro Picardi (1949) received the degree in Electronics Engineering from the University of Naples/Italy in 1975. He is currently Associate Professor in Process Control at the Department of Electronic Computer and System Science of the University of Calabria. Italy. His current research interests are in the area of electrical drives robotics neural networks and fuzzy control. (University of Calabria Electronic. Compu

An artificial‐neural‐network (ANN) application for steady‐state security evaluation of electrical power systems is presented. Such application is based upon a combined use of a multilayer back‐propagation neural network and of an opportune electrical system model, previously proposed by some of the authors. In the paper, the definition of steady‐state security and the problems arising from its on‐line evaluation are briefly recalled. Then, the ANN utilized is described with particular reference to the solutions adopted by the authors. Afterwards, some remarks on the system model utilized are reported. Finally, numerical applications on the AEP‐14 bus system are presented and the results obtained with different ANN configurations are analyzed. Copyright © 1995 John Wiley & Sons, Ltd.

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ISDN LOOP EXTENSION USING A MID-SPAN AMPLIFIER

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 1995年第3期8卷 219-224页

作者： ERKER, GJ DODDS, DE KRZYMIEN, WA David E. Dodds was born in Saskatoon Canada in 1945. He received the B. Eng. and MSc. degrees from the University of Saskatchewan in 1966 and 1968 respectively. He worked with Bell Northern Research (Ottawa) on PBX design in 1969 1972 and 1978. Since 1969 he has been with the University of Saskatchewan where he is currently Professor of Electrical Engineering. He teaches courses in electronics and communications and also presents short courses on the fundamentals of telephony. Current research interests are in data transmission signal processing architecture and frame synchronization for PCM and spread spectrum systems. He has been granted five patents relating to commercial products in delta-modulation telephone line interfacing and computer data transmission. In 1986 he was on sabbatical leave at BNR Inc. and worked with an ANSI committee on the standardization of FDDI-II a combined voice and data system. Mr. Dodds is a Registered Consulting Engineer in Saskatchewan. Witold A. Krzyden received his MSc. (Eng.) and Ph.D. degrees (both in Electrical Engineering) in 1970 and 1978 respectively from the Poznan Technical University in Poznan Poland. He was awarded the Minister's of Science and Technology Prize of Excellence for his Ph.D. thesis. From 1970 to 1978 he was a Research Engineer and Teaching Assistant and then from 1978 to 1980 an Assistant Professor of Electrical Engineering at the Poznan Technical University. In 1980 he won a Dutch Government Research Fellowship at the Twente University of Technology in Enschede the Netherlands for the year of 1980/1981. In the following year of 1981/82 he was a Research Assistant Professor there. From 1982 to 1986 he was an Assistant Professor of Electrical Engineering at Lakehead University in Thunder Bay Ontario Canada. In 1986 he joined the Univeristy of Alberta and Alberta Telecommunications Research Centre (now Telecommunications Research Laboratories or TRLabs) as an Associate Professor of Electrical Engineering. Currently he is a Professor of E

The 5.5 km range of the basic rate ISDN loop has been extended by using a negative impedance amplifier and by using a 2 wire/4 wire (2w/4w) amplifier. The negative impedance amplifier extends the range of the loop by 1.0 km, whereas the 2w/4w amplifier extends the range by 1.5 km at the expense of increased complexity. As part of the amplifer design, a resistor/capacitor network has been developed which closely matches the characteristic impedance of telephone cable. Error rate tests have been conducted using various lengths of cable and an operating ISDN line.

关键词： ISDN PHYSICAL LAYER BASIC RATE LOOP RANGE EXTENSION

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Distributed automation control using broadcasting networks

Distributed automation control using broadcasting networks

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International Conference on Industrial Electronics, Control and Instrumentation

作者： I. Lobl P. Morel Department of Microengineering Laboratory of Methods and Techniques for Assembly Swiss Federal Institute of Technology Lausanne Switzerland Department of Computer Science Laboratory of Industrial Computing Swiss Federal Institute of Technology Lausanne Switzerland

Assembly stations, also known as cells, is a generalised term denoting the place where one of the operations is carried out in the sequence needed to assemble a product. As each station is in general dedicated to a specific operation for a specific product, it is uncommon to find two instances of the same station. Stations are custom designed and expensive. The authors have developed standard modular assembly station components that one just has to "plug together to operate". The authors present in this paper an original solution using the LAN system from LonWorks. This solution is at present operational on real production and test cells.< >

关键词： Automation Distributed control Automatic control Broadcasting Assembly Standards development Field buses Laboratories Local area networks Production

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ANALYSIS AND CAD TECHNIQUES FOR PERIODIC LEAKY-WAVE PRINTED ANTENNAS - NUMERICAL AND EXPERIMENTAL RESULTS

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INTERNATIONAL JOURNAL OF MICROWAVE AND MILLIMETER-WAVE computer-AIDED ENGINEERING 1994年第1期4卷 88-99页

作者： ENCINAR, JA Department of Electromagnetism and Circuit Theory Universidad Politécnica de Madrid 28040 Madrid Spain Jose A. Encinar was born in Madrid Spain in 1957. He received the “Ingeniero de Telecomunicacion” and PhD degrees both from the Universidad PolitCcnica de Madrid in 1979 and 1985 respectively. Starting in January of 1980 he was with the Grupo de Electromagnetismo Aplicad0 y Microondas at the Universidad Politecnica de Madrid as a teaching and research assistant from 1980 to 1982 and as an assistant professor from 1983 to 1986. In 1986 he became associate professor. From February to October of 1987 he was at Polytechnic University Brooklyn NY as a postdoctoral fellow of the NATO Science Program. He is currently a professor in the Electromagnetism and Circuit Theory Department at the Universidad Politecnica de Madrid. His research interests include analytical and computer-aided techniques for solving electromagnetic problems in waveguide structures and radiating systems.

Theoretical and experimental results are presented for a printed leaky-wave antenna. Mode-matching and EDC methods have been used to analyze the antenna and to design the prototypes. Reflection, transmission, and radiation measurements have been compared with theoretical predictions with good agreement. A CAD procedure is proposed to reduce the sidelobe level by tapering width and separation of metal strips. (C) 1994 John Wiley & Sons, Inc.

关键词： Antennas

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NUMERICAL-ANALYSIS OF DISCONTINUITIES IN A RECTANGULAR WAVE-GUIDE LOADED WITH ISOTROPIC OR ANISOTROPIC OBSTACLES BY MEANS OF THE COUPLED-MODE METHOD AND THE MODE-MATCHING METHOD

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INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 1994年第6期7卷 433-452页

作者： SOLANO, MA VEGAS, A PRIETO, A Universidad de Cantabria—Departamento de Electrónica Avda. de los Castros s/n 39005 Santander Spain Since 1985 he has been with the Electronics Department at the University of Cantabria with a scholarship from the Spanish Ministry of Education and Science working on the analysis and design of passive devices in dielectric guides and anisotropic waveguides. He is currently Assistant Professor in the Department of Electronics of the University of Cantabria. His current research activities include electromagnetic propagation in waveguide structures and numerical methods in electromagnetics. From 1977 to 1983 he was with the Department of Electronics at the University of Cantabria where he became Associate Professor in 1984. He has worked in electromagnetic wave propagation in plasmas and microwave interferometry. His current research and teaching interests include electromagnetic theory computer methods in electromagnetics and microwave measurements. Andrés Prieto was born in Santander Spain in 1947. He received the Licenciado en Ciencias Fisicas degree in 1973 from the Universidad de Valladolid Spain and the doctor's degree in 1979 from the Universidad de Santander Spain. He was made Profesor Titular in the Departamento de Electronica de la Universidad de Cantabria in 1983 and has been Catedratico since 1993. He is currently working in the area of analytical and numerical methods of solving electromagnetic problems in waveguide structures and microwave circuits.

A hybrid method obtained as a combination of the coupled-mode method (CMM) and the mode-matching method (MMM) is developed and applied in the analysis of multiple dielectric and magnetic discontinuities in rectangular waveguides. As both are moment methods, some kind of truncation has to be carried out in the computer implementation. It is shown that selection of a different number of modes in the two methods is not necessary, unless low-permittivity media inside the waveguide are considered. As a consequence, the procedure for selecting the number of basis functions is only done in one of the methods. Numerical examples are presented showing the behaviour of the method and the proofs of convergence. Examples are included illustrating the power of this hybrid technique, especially in relation to non-reciprocal structures containing magnetized ferrites.

关键词： Rectangular waveguides

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3-D EDGE ELEMENT ANALYSIS OF DIELECTRIC-LOADED RESONANT CAVITIES

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INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 1994年第1期7卷 35-41页

作者： ZHU, ZL DAVIES, JB FERNANDEZ, FA Department of Electronic and Electrical Engineering University College London WC1E 7JE U.K. On leave from the Department of Radio Electronics Peking University Beijing 100871 People's Republic of China. Le-zhu Zhou was born in Guizhou China in 1944. He received the B.S. degree in Physics and M.S. degree in Electronics from Peking University Beijing China in 1968 and 1981 respectively. Since 1981 he has been on the staff of the Department of Radio-Electronics of Peking University. In 1983 he was appointed as a Lecturer. In 1989 he became an Associate Professor. Since September 1991 he has been doing research as an Academic Visitor at the Department of Electronic and Electrical Engineering of University College London. He has been engaged in the electromagnetic field theory and its application. Recently his research interest has been in the computer modelling of optical and microwave structures by using edge element methods. J. Brian Davies was born in Liverpool England in 1932. He received the B.A. degree in mathematics in 1955 from Jesus College Cambridge England. He received the M.Sc. degree in mathematics the Ph.D. degree in mathematical physics and the D.Sc. (Eng) degree in engineering in 1957 1960 and 1980 respectively from the University of London England. From 1955 to 1963 he worked at the Mullard Research Laboratories Salford Surrey England except for two years spent at University College London. In 1963 he joined the academic staff of the Department of Electrical Engineering University of Sheffield England. Since 1967 he has been on the staff at University College London where he is now Professor of Electrical Engineering. From 1971 to 1972 he was Visiting Scientist at the National Bureau of Standards Boulder CO. In 1983 he was a Visitor at the Department of Engineering Science University of Oxford England. From 1988 to 1989 he was a Visiting Professor at the University of Colorado Boulder CO. His research interests have included microwave and optical aspects of electr

The eigenmodes in electromagnetic cavities, loaded with arbitrarily shaped dielectric materials, are computed by the edge element method. The computation shows that the well known 'spurious modes' no longer appear. Formulae are given and verified so that the number of zero eigenvalues, which come from del x H = 0, may be accurately predicted. Formulae for the order and density of the global matrices are given for a rectangular cavity regularly divided into bricks and tetrahedra, allowing an associated comparison between the contrasting edge and nodal element formulations. Comparison of the computed results with available theoretical and previously published data show the edge element approach to be a robust, accurate and effective method.

关键词： Dielectric waveguides

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SYSTEM DESCRIPTION OF LAMBDALG - A HIGHER-ORDER ALGEBRAIC SPECIFICATION LANGUAGE 4th

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4th International Conference on Logic Programming and Automated Reasoning (LPAR 93)

作者： GUI, YX OKADA, M Logic and Formal Methods Lab Department of Computer Science Concordia University Montréal H3G 1M8 QC Canada

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