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ISDN LOOP EXTENSION USING A MID-SPAN AMPLIFIER

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

关键词： ISDN PHYSICAL LAYER b.SIC RATE LOOP RANGE EXTENSION

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PERFORMANCE OF A PRIORITIZED ON-b.ARD b.SEb.ND SWITCH FOR A MULTISERVICE MULTIb.AM SATELLITE

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 283-297页

作者： b.HM, S ELHAKEEM, AK HACHICHA, M Department of Electrical and Computer Engineering Concordia University 1455 De Maisonneuve Blvd. West Montreal H3A 1M8 Canada Was born in Montreal Canada on 14 September 1966. He received the B. Eng. degree in electrical engineering from Concordia University Montreal Canada in 1989. He is at present completing the M.A.Sc. degree in electrical engineering at Concordia University. (S'75–S'79–M'79–SM'86) received the Ph.D. degree from Southern Methodist University Dallas TX in 1979. He spent the next two years working as a Visiting Professor in Egypt after which he moved to Ottawa Canada in 1982. He assumed teaching and research positions in Carleton and Manitoba Univerities and later moved to Concordia University Montreal Canada in 1983 where he is now a Professor in the Electrical and Computer Engineering Department. He has published numerous papers in IEEE and international journals in the areas of spread spectrum and networking. He is a well-known expert in these areas and serves as a consultant to many companies. His current research interests include wide-band metropolitan networks switching architectures and performance of on-board multibeam satellites acquisitionless CDMA networks code distribution and orthogonalization of CDMA signals responsive congestion control for ATM-based networks ARQ techniques and investigation of the novel SUGAR CDMA systems in fading channels. Dr. Elhakeem is a Senior Member of the Canadian Electrical Engineering Society and Armed Forces Association. He has chaired numerous technical sessions in IEEE Conferences was the Technical Program Chairman for IEEE Montech 1986 Montreal Canada. Dr. Elhakeem is the key guest editor of theIEEE Journal of Selected Areas in Communicationsfor the May June issues 1993 covering CDMA networks. Advanced Technology & Networks VISTAR Telecommunications Inc. Ottawa Ontario K1G 3J4 Canada An Associate Director of Advanced Technology & Networks Group VISTAR Telecommunications Inc. Ottawa Canada. He is also an Adjunct Pr

In this paper, we study the performance of a prioritized on-b.ard b.seb.nd switch in conjunction with a multib.am satellite handling integrated services. The services considered for the analysis include voice, video, file transfer and interactive data. The prioritized switch uses b.th input and output b.ffering, switch speed-up as well as a two-phase head-of-line resolution algorithm, in order to reduce the b.ffer loss while maintaining acceptab.e user delays. The minimum required b.ffer capacity and switch speed-up for each service in a prioritized environment are found under uniform traffic conditions. It is shown that under uniform traffic conditions, only minimal b.ffering and switch speed-up are needed even for the lowest priority users. The performance dependence on the switch size is also sub.tantially reduced with head of line resolution and b.ffering even in a prioritized environment.

关键词： SWITCH ON-b.ARD b.SEb.ND MULTIb.AM PRIORITIZED HEAD-OF-LINE UNIFORM LOAD SPEED-UP

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Real-time issues in the design of the Data Management System for the Space Station Freedom

Real-time issues in the design of the Data Management System...

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1993 IEEE Workshop on Real-Time Applications, RTA 1993

作者： Davari, S. Leib.ried, T.F. Natarajan, S. Pruett, D. Sha, L. Zhao, W. Dept. of Comput. Sci. Houston Univ. Clear LakeTX77058-1057 United States Department of Computer Science Texas AandM University College StationTX77843-3112 United States NASA Lyndon B. Johnson Space Center HoustonTX77058 United States Software Engineering Institute Carnegie Mellon University PittsburghPA15213 United States

ISBN: (纸本)0818641304

Space Station Freedom (SSF) faces several challenges which are unique in the NASA history of manned and unmanned spacecraft systems. The challenges include a 30 year life, and evolution in capab.lity of the station as a science platform and potentially a transportation node for manned missions to the solar system. The Data Management System (DMS) is a key element of SSF. DMS is the computational infrastructure of SSF, responsib.e for integrating information onb.ard into a cooperative whole. Its primary role is to provide integrated data processing and communication services for b.th the core function and the payloads. The authors focus on some real-time issues in the design of DMS. © 1993 IEEE.

关键词： Space stations

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Real-time issues in the design of the Data Management System for the Space Station Freedom

Real-time issues in the design of the Data Management System...

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IEEE Workshop on Real-Time Applications

作者： S. Davari T.F. Leib.ried S. Natarajan D. Pruett L. Sha W. Zhao Dept. of Comput. Sci. Houston Univ. Clear Lake TX USA Department of Computer Science University of Houston Houston TX USA Department of Computer Science Texas A and M University College Station TX USA NASA Lyndon B. Johnson Space Center Houston TX USA Software Engineering Institute Carnegie Mellon University Pittsburgh PA USA

关键词： Real time systems Space stations NASA Hardware Application software Data processing computer architecture computer science FDDI Operating systems

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CONCURRENT b.UNDARY-ELEMENT COMPUTATION

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INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 1993年第2期6卷 83-98页

作者： MCDOWALL, DS LEE, TW FUSCO, VF Microwave Research Group Department of Electrical and Electronic Engineering The Queen's University of Belfast Ashby Building Stranmillis Road Belfast BT9 5AH Northern Ireland U.K. D. Stewart McDowall was born in Dublin epublic of Ireland in 1967. He received the M. Eng. degree in Electrical and Electronic Engineering from the Queen's University of Belfast in 1990. In the same year he was presented with a Distinction Award from the Department of Education of Northern Ireland and he is currently pursuing his Ph.D. in the Microwave Research Group at Q.U.B. His principal research area is the electromagnetic field mapping of microwave systems using concurrient programming. He is an Associate Member of the Institute of Electrical Engineers. Lee Thaim Wee was awarded the degree of B. Eng. in Electronics from the Queen's University of Belfast in July 1991. He is currently serving in the Malaysian Armed Forces. Vincent F. Fusco was educated at the Queen's Univeristy of Belfast where he obtained the degree of Ph.D. in 1982. He has worked as a research engineer on short-range radar and radio telementry systems. Currently he is a reader in Microwave Communications in the School of Electrical Engineering and Computer Science the Queen's Univeristy of Belfast. His current research interests include non-linear microwave circuit simulation and concurrent programming techniques for electromagnetic field problems with particular emphasis on EMC applications. He has published numerous research papers in these areas. He is the author of the bookMicrowave Circuits Analysis and Computer Aided Design Prentice-Hall 1987. Dr Fusco is a Chartered Electrical Engineer and a Member of the Institute of Electrical Engineers.

A major limitation of the b.undary element method (b.M) for the solution of electrical potential prob.ems is the long computational time required. However, a large portion of the calculations involved can b. viewed as b.ing parallel in nature and can therefore b. computed concurrently. This paper makes an effort to increase the efficiency of the b.M process using transputer-b.sed multiprocessor computing techniques. The algorithms developed may equally well b. applied to any multiprocessor system. The application selected to demonstrate the technique is the solution of an electrostatic prob.em governed b. a two-dimensional Laplace equation. A parallel algorithm for prob.em setup and field extraction using b.M is designed and implemented on a transputer array. Special attention is directed to the utilization of the parallel processors to achieve maximum efficiency. The analysis in this work concentrates on the communication strategies for passing data b.tween processors as well as a consideration of the workload attrib.ted to each processor. The parallel algorithms were implemented using 3L Parallel Fortran;however, the choice of topology for the overall b.M implementation was limited b. the fact that certain parts of the algorithm could only utilize a pipeline configuration of processors. Comprehensive results for the parallel b.M algorithm are given and they are encouraging, indicating that parallel processing has much to offer when applied to the b.undary element method.

关键词： b.undary element method

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An approach to the direct analysis of transient stab.lity

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European Transactions on Electrical Power 1993年第3期3卷 241-248页

作者： Djukanovic, M.b. Sob.jic, D.J. Pao, Y.‐H. Miodrag B. Djukanovic (1959) received his B.S. M.Sc. and Ph.D. degrees in Electrical Engineering from the University of Belgrade/Yugoslavia in 1982 1985 and 1992 respectively specializing in electric power systems. In 1984 he joined the Electrical Engineering Institute “Nikola Tesla” in Belgrade where he was working on the scientific studies in the field of power systems planning operation and control. In 1985 and 1990 he was appointed as a research scholar at the Royal Institute of Technology Stockholm and Case Western Reserve University Cleveland Ohio. His major in- terests are in the area of power system analysis steady-state and dynamic security and application of neural networks in electric power systems. (Electrical Engineering Institute “Nicola Tesla” ul. Koste Glavinica 8A YU-11000 Belgrad T +3811/2351-619 Fax + 3811/2351-823) Dejan J. Sobajic (1949) received the B.S.E.E. and the M.S.E.E. degrees from the University of Belgrade/Yugoslavia in 1972 and 1976 respectively and the Ph.D. degree from Case Western Reserve University Cleveland Ohio in 1988. At present he is with the Department of Electrical Engineering and Applied Physics Case Western Reserve University Cleveland. He is also the Engineering Manager of A1 WARE Inc. Cleveland. His current research interests include power system operation and control neuralnet systems and adaptive control. He is a member of the IEEE Task Force on Neural-Network Applications in Power Systems and of the IEEE Intelligent Controls Committee. He is the Chairman of the International Neural-Networks Society Special Interest Group on Power Engineering. (Case Western Reserve University Department of Electrial Engineering and Computer Sciences Glennan Building Ohio 44 106 USA T + 1216/421-2380 Fax +1216/368-8776) Yoh-Han Pao (1922) has been a Professor of Electrical Engineering and Computer Science at Case Westem Reserve University (CWRU) Cleveland Ohio since 1967. He has served as chairman of the University's Electrical Engineering Department

The Transient Energy Function (TEF) method has b.en intensely investigated over the last decade as a reliab.e and accurate tool for transient stab.lity assessment of multimachine power systems. In this paper we propose the Potential Energy b.undary Surface (PEb.) b.sed method for direct analysis of transient stab.lity. The critical value of transient energy and the Critical Clearing Time (Tb.CCTb.) are evaluated without the need for successive calculation and memorization of the system kinetic and potential energy values along the sustained fault trajectory. The method is used for determination of output features in the training phase of the neural‐net b.sed transient security assessment. The proposed approach is tested on the well‐known ten‐generator New England test system demonstrating the validity and accuracy of ob.ained results. Copyright © 1993 John Wiley & Sons, Ltd.

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Stab.lizers enhancing the frequency regulation action of HVDC links supplying weak AC systems

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European Transactions on Electrical Power 1993年第3期3卷 201-212页

作者： Maris, T.I. Lygdis, A.D. Vovos, N.A. Giannakopoulos, G.b. Theodoros I. Maris (1961) received the Diploma in Electrical Engineering from the University of Patras/Greece in 1984. In 1985 he joined the Power Systems Laboratory at the Electrical Engineering Department of the University of Patras as research assistant where he is currently working for his Ph.D. degree. His area of interest is HVDC transmission. (University of Patras Dep. of Electrical Engineering Power Systems Laboratory GR-26 500 Rion. Patras/Greece T +3061/997350 Fax +3061/997362) Athanassios D. Lygdis (1954) received the Diploma in Electrical Engineering from the University of Patras/Greece in 1979. From 1979 until 1982 he worked at the Nuclear Technology Laboratory of the University of Patras as research assistant. In 1983 he joined the Power Systems Laboratory at the Electrical Engineering Department of the University of Patras as scientific collaborator. He is now working for his Ph.D. degree in this Department. His main field of interest is power transmission by HVDC systems. (University of Patras Dep. of Electrical Engineering Power Systems Labora- tory GR-26 500 Rion Patras/Greece T + 3061/997350 Fax + 3061/997361) Nickolas A. Vovos (1951) received the Diploma degree from the University of Patras/Greece the M.Sc. degree from the University of Manchester/England Institute of Science and Technology. and the Ph.D. degree from the University of Patras in 1974 1975 1978 respectively all in Electrical Engineering. In 1976 he joined the Power Systems Laboratory at the Electrical Engineering Department of the University of Patras where he is now Associate Professor. His main fields of interest are the modeiling and the transient stability study of integrated AC/DC systems. He is a member of the IEEE Power Engineering Society and CIGRE and a registered professional Engineer and member of the Technical Chamber of Greece (University of Patras Dep. of Electrical Engineering Power Systems laboratory GR-26500 Rion Patras/Greece. T +3061/997369 Fax +3061/997362) Gabriel B. Giannakopoulos (1

Power System Stab.lizers (PSS) superimposed to the b.sic control system of an HVDC link supplying a weak AC system, in order to enhance its frequency regulation action, are proposed. To decrease the AC voltage sensitivity at the inverter side, the b.sic control system of the HVDC link is proposed to operate with the rectifier under Minimum Ignition Angle (MIA) control and the inverter under Constant Current (CC) control. Inputs to the PSS are the frequency and the AC voltage deviations at the inverter side and their constant parameters are calculated using modal control technique. Detailed simulation results for a practical integrated AC/DC system are presented to evaluate the performance of the proposed control scheme. Copyright © 1993 John Wiley & Sons, Ltd.

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An evaluation of the instantaneous calculation of load current components

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European Transactions on Electrical Power 1993年第1期3卷 53-59页

作者： Marshall, D.A. Venter, F.P. van Wyk, J.D. Dr. Dirk Adriaan Marshall (1960) is an Industrial Research fellow with the Energy Laboratory at the Rand Afrikaans University Johannesburg/RSA. He is employed by Eskom (National Electric Company RSA) in the Transmission Engineering Division where his corporate responsibility includes high voltage direct current transmission and voltage quality. He obtained the 8. Eng. M. Eng. and D. Eng degrees in 1983 1985 and 1990 respectively from the Rand Afrikaans University. He was co-recipient of one IEEE Prize Paper Award. (Transmission Engineering Division Megawattpark P.O. Box 1091 Johannesburg 2000 Republic of South Africa T +2711/800-3250 Fax +27 11/800-2779) Frederik Petrus Venter (1966) received the B. Eng. and hit. Eng. degrees from the Rand Afrikaans University Johannesburg/RSA in 1989 and 1991 respectively. He has at present submitted a Thesis for the D. Eng. degree at the same University. His field of interest includes power electronic applications in high voltage networks and Active Power Filtering. He was co-recipient of one IEEE Prize Paper Award. (Rand Afrikaans University Laboratory for Energy P.O. Box 524 Johannesburg 2000. Republic of South Africa T + 2711/489-2454 Fax + 2711/489-2466) Dr. Jacobus Daniel Van Wyk (1939) received the M. Sc. Eng. degree from the University of Pretona/RSA and the degree of Doctorate of Technical Science from the University of Technology Eindhovenmhe Netherlands in 1966 and 1969. He has worked with the S.A. Iron and Steel Corporation. the University of Pretoria and was on the technical and scientific staff of the University in Eindhoven. between 1961 and 1972. From 1971 to the present he has been a Full Professor of Electrical and Electronic Engineering at the Rand Afrikaans University Johannesburg/RSA at present holding a chair in Power Electronics and has been involved in extensive industrial work. He is at present Programme Director of the Electronic Power Control Research Group in the Energy Laboratory of the Faculty of Engineering. Since 1976 he

The development of theoretical techniques for the instantaneous calculation of load current components is evaluated. The associated instantaneous calculation of load power components is also evaluated since it is used in the calculation of the currents. The generation of these different power components with respect to compensation are pointed out. Further implementation of the instantaneous power theory is discussed. A three‐phase vector approach to the instantaneous calculation of power components is also discussed. Experimental results ob.ained b. using the instantaneous power theory are illustrated. Copyright © 1993 John Wiley & Sons, Ltd.

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Real virtual environment applications - Now 3

Real virtual environment applications - Now

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3rd Conference on Visualization, VIS 1992

作者： b.een, Paul T. Grinstein, Georges G. Mizell, David W. Satava, Richard M. Smith, b.adford Stephens, Michael M. Zeltzer, David Department Head Applied Technology MITRE Corporation BedfordMA United States Continental C3 MITRE Corporation BedfordMA United States Institute for Visualization and Perception Research Computer Science Department University of Massachusetts Lowell LowellMA United States Computing Systems and Environments Boeing Computer Services SeattleWA United States General Surgery Silas B. Hays Army Hospital Fort OrdCA United States University of San Francisco BerkeleyCA United States System Engineering Division Computer Sciences Corporation VicksburgMS United States Computer Graphics and Animation Group Media Laboratory Massachusetts Institute of Technology CambridgeMA United States

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PROGRESSIVE PACKER ZONE SAMPLING METHOD FOR VOC PLUME DELINEATION IN CONSOLIDATED AQUIFERS

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GROUND WATER MONITORING AND REMEDIATION 1992年第3期12卷 108-111页

作者： LANEY, SE ENb.RG, CA S.E. Laney received a B.S. in geology from Arkansas Tech University in Russellville and an M.S. in geology from the University of Arkansas Fayetteville. Currently he is manager of the Geology/Hydrogeology Department of the Site Investigations Group at Recon Systems Inc. (P.O. Box 130 Raritan NJ 08869). Laney is a Certified Professional Geologist and a New Jersey Licensed Well Driller. He is also a registered geologist in Arkansas Maine and Tennessee. C.E. Enberg received a B. S. in petroleum engineering and an M.S. in petroleum engineering with a minor in hydrogeology from Montana College of Mineral Science and Technology in Butte. Formerly he was a research assistant at the Montana Bureau of Mines and Geology and then an engineering hydrologist in the Geology/Hydrogeology Department of the Site Investigations Group at Recon Systems Inc. Enberg is a New Jersey Licensed Well Driller and also a Licensed Monitor Well Constructor in Montana. Currently he is a project hydrogeologist with Superior Environmental Corp. (2201 Wolf Lake Rd. Muskegon MI 49442).

The progressive packer/zone sampling method was used to identify the b.ttom of a plume of volatile organic compounds (VOCs) in the parts-per-million (ppm) range using one well in each of three separate locations. The method involves progressively drilling a 20-foot length of b.rehole through casing, setting an inflatab.e packer at the top of the drilled zone, purging the zone of three volumes of water using the airlift method, sampling the zone in situ through the packer string using a b.iler, then repeating the procedure. A plume consisting of chlorinated VOCs, alcohols, and vinyl chloride occurs in a low-yielding fractured b.drock aquifer located in the Passaic Formation at a site in central New Jersey. The thickness of the plume in total VOC concentrations exceeding 1 ppm was determined using the progressive packer/zone sampling method to a depth of 200 feet. The first b.rehole was completed as a monitoring well in the "hottest" zone encountered, during testing. Additional wells were then clustered with this exploratory well to delineate the plume in the parts-per-b.llion (ppb. range. Cross contamination from previously sampled zones was not a prob.em as long as total VOCs in the ppm range were targeted and the sample interval was properly purged. Instead of using a multiple well cluster consisting of an indefinite numb.r of wells to determine the b.lk thickness of a plume at a specific location, information from one b.rehole may suffice during the exploratory phase. Costs to the client and cross contamination potential to the aquifer can b. minimized b. limiting the numb.r of b.reholes needed for vertical delineation.

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