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Power Tech Conference

作者： T. Kruger R. Patsch Institute for Industrial Data Processing and Communication (IDK) Mannheim University of Applied Sciences Germany Institute of Materials & Diagnostics in Electrical Engineering University of Siegen Germany

Two procedures are presented which perform noise reduction up to 50+ dB of partial discharge measurements (PDM) in real-time using the frequency domain and digital signal processing, both based on classical PDM. The first solution uses the signal collection from two sources, one of them the usual PDM, the other a reference signal source to track the noise signals influencing the PDM. In the frequency domain as a first step a transfer function will be calculated between the two noise signals of PDM and of the reference. In the second step this transfer function is used to subtract the noise signal from the PDM signal. The second solution makes use of the different spectral characteristics of partial discharge (PDP) pulses and noise signals. Whereas the energy of PDP is spread over a wide frequency range most noise signals are concentrated on various frequencies, so removing high-energy spectral lines removes most of the noise.

关键词： Active noise reduction Partial discharge measurement Frequency domain analysis Frequency measurement Noise measurement Noise reduction Partial discharges Pulse power systems Power measurement Power system reliability

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Resampling routine on heterogeneous networked-based environment

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Journal of the Indian Society of Remote Sensing 2002年第1-2期30卷 7-13页

作者： Gupta, P. Khanna, V. Onong, T. Rao, Thirunadha Dube, N. Dhar, D. Ramakrishnan, R. Majumder, K.L. Department of Computer Science and Engineering Indian Institute of Technology Kanpur - 208016 India Image Processing and Data Product Group Space Applications Centre Ahmedabad - 380 053 India

In this paper, we have described a model to parallelize the resampling routine, which is used in the geometric correction of data provided by remote sensing satellites. Our model is a typical master-slave model consisting of N machines termed as hosts out of which one is designated as the master. The input image data resides on the master. processing of the input image data is done in parallel on the N machines. Issues related to load-balancing and various error conditions that may occur during execution like one of the machines going down have been studied and are incorporated in the model. It also provides the flexibility to add or delete the hosts during the execution of the resampling routine. The serial version of this routine involves huge amount of computations and takes substantial amount of time even for an image of 473 MB. We have implemented our model with the help of PVM which is most often used in distributed computing environment. Our approach has been tested for geometric correction on LISS-III 4 band data of size 473 MB. It is found that if one uses 2. 3 or 4 hosts the overall execution time is reduced by 33%, 42% and 49%, respectively.

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A simplified criterion for repeatability and its application in constraint path planning problems

A simplified criterion for repeatability and its application...

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Proceedings. 2000 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2000) (Cat. No.00CH37113)

作者： R. Schaufler C.H. Fedrowitz R. Kammuller Department of Electrical Engineering Institute for Data Processing Germany

Compared to typical industrial manipulators, redundant manipulators offer more dexterity and flexibility because of their ability to reach points in their workspace in many different ways, e.g. they can perform self-m... 详细信息

关键词： Path planning data processing Kinematics Jacobian matrices

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An algebra for efficiently solving the continuous collision detection problem

An algebra for efficiently solving the continuous collision ...

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Proceedings. 1998 IEEE/RSJ International Conference on Intelligent Robots and Systems. Innovations in Theory, Practice and Applications (Cat. No.98CH36190)

作者： C.H. Fedrowitz F. Duber Department of Electrical Engineering and Computer Science Institute for Data Processing University of Siegen Siegen Germany

An efficient object-oriented collision detection engine has been developed being applicable for complex geometrical models defined constructively and for geometrical primitives which representation base on the widely used boundary representation geometric solid modeler ACIS. An approach, which in a fast pre-processing step reduces the model's complexity by efficiently eliminating those objects from further examinations which do not collide, has been examined. Principally basing on Cameron's S-bound theory (1989, 1990), the approach has been improved by the definition of an algebra for bounding operations and has been adapted for use with ACIS. A new method for solving the continuous collision detection problem is presented offering an algebra on the four-dimensional S-bounds also defined by Cameron.

关键词： Algebra Object oriented modeling Solid modeling Object detection Lattices Computational modeling Hardware Shape Convergence data processing

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A new high precision wide area DGPS system

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JOURNAL OF NAVIGATION 1997年第1期50卷 109-119页

作者： Ashkenazi, V Chao, CHJ Chen, W Hill, CJ Moore, T [a1 ](Institute of Engineering Surveying and Space Geodesy The University of Nottingham)This paper describes an advanced method and the corresponding algorithms which could provide a high precision Wide Area Differential GPS (WADGPS). The service would be suitable for single or dual frequency users and could be introduced with very few reference stations. The two main components of the service are a precise near real-time orbit determination of the GPS satellites and an accurate estimation and modelling of ionospheric and tropospheric effects. Broad principles of the processing algorithms and results of both simulation and real data tests are described. User positioning accuracies of better than 25 m (r.m.s.) in plan and 30 m (r.m.s.) in height are achieved by both single and dual frequency scenarios.Wide Area Differential GPS (WADGPS) is being developed to overcome the main drawbacks of conventional or Local Area Differential GPS (LADGPS) where positional accuracy of a user degrades as the reference-to-user separation increases. The spatial decorrelation of the error sources notably the atmospheric propagation and satellite orbital errors inherent in GPS are the main causes of this accuracy degradation. Several organizations are involved in WADGPS research and different conceptual approaches have been suggested. The proposed methods all share a common basic assumption: that the error sources which affect the system are broken down into individual error components and are modelled separately. The variance between the different techniques comes from the way in which the different error components are modelled.

This paper describes an advanced method, and the corresponding algorithms, which could provide a high precision Wide Area Differential GPS (WADGPS). The service would be suitable for single or dual frequency users, and could be introduced with very few reference stations. The two main components of the service are a precise, near real-time orbit determination of the GPS satellites, and an accurate estimation and modelling of ionospheric and tropospheric effects. Broad principles of the processing algorithms and results of both simulation and real data tests are described. User positioning accuracies of better than 2.5 m (r.m.s.) in plan and 3.0 m (r.m.s.) in height are achieved by both single and dual frequency scenarios.

关键词： satellite navigation differential systems

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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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Development and application of MCAL tools for marine radar instruction

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Computer Applications in engineering Education 1995年第4期3卷 259-259页

作者： Guirguis, S. Korany, E. Abdel-Bary, A. Institute of Graduate Studies and Research Alexandria University Alexandria Egypt Shawkat K. Guirguis:obtained the BSc and M.Sc. degrees in Computer Science and Automatic Control Faculty of Engineering Alexandria University in 1981 and 1984 respectively. In 1988 he obtained a PhD degree in Electronics and Communications Faculty of Engineering Cairo University co-supervised by the Imperial College of Science and Technology University of London where he spent two years as an academic visitor. His current research interests include software quality management multimedia automatic programming and decision support systems. He is currently a lecturer of Computer Science at the Institute of Graduate Studies & Research Alexandria University. Ezzat A. Korany:received the BS degree in Electrical Engineering (Electronics Section) from the University of Alexandria Egypt in 1971 the MS degree in Electrical Engineering (Computer Section) from Ain Shams University Cairo Egypt in 1977 and the PhD degree in Electrical Engineering (Digital Systems) from Florida Institute of Technology U.S.A. in 1982. He is currently an associate professor of Computer Science at the Institute of Graduate Studies & Research University of Alexandria. His research interests are in data communications and multimedia applications computer networks image processing and pattern recognition. Abdel-Latif A. Abdel-Bary:obtained the BEng degree in Electronics Technology from Arab Maritime Transport Academy in 1986. In 1995 he obtained the MSc degree in Information Technology from the Institute of Graduate Studies & Research Alexandria University. His current research interests include ICAL hypermedia and automatic programming.

In this article a multimedia computer-assisted learning (MCAL) system is presented. The major objective of this work was to investigate the potential of using such systems as tools for transferring instructional course information through various types of computer media as opposed to the classic CAL systems. The philosophy and techniques employed to design the system are investigated. Usage of the implemented system and its merits have been illustrated through its application to teach engineering students and technicians the theory and concepts of marine radar. System design, implementation, test, and revision phases are presented and discussed.

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An implementation of parallel production systems with two load balancing mechanisms

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SYSTEMS AND COMPUTERS IN JAPAN 1995年第14期26卷 1-14页

作者： Miyazaki, J Yokota, H Member School of Information Science Japan Advanced Institute of Science and Technology Ishikawa-ken Japan 923 Received his B.E. degree from Tokyo Institute of Technology Tokyo Japan in 1992 and his M.S. degree from Japan Advanced Institute of Science and Technology (JAIST) Ishikawa Japan in 1994. He is a Ph.D. student at School of Information Science JAIST. His research interests include parallel rule base systems active database systems and high performance I/O systems. He is a member of the Institute of Electronics Information and Communication Engineers of Japan and Information Processing Society of Japan. Received his B.E. M.E. and Dr. of Eng. degrees from Tokyo Institute of Technology in 1980 1982 and 1991 respectively. He joined Fujitsu Ltd. in 1982 and was a researcher at the Institute of New Generation Computer Technology (ICOT) from 1982 to 1986 and at Fujitsu Laboratories Ltd. from 1986 to 1992. He is an Associate Professor of School of Information Science Japan Advanced Institute of Science and Technology (JAIST). HIS research interests include parallel computer architecture for databases and data engineering. He is a member of IPS I.E.I.C.E. JSAI IEEE and ACM.

An implementation method is proposed for parallel production systems on multicomputers, or message-passing computers, to speed up execution time. There have been proposed parallel production systems using hash mechanism, but they cause a skewed load distribution problem. To obtain more efficient balance of load, the method addressed here and named clustered parallel production systems (CPPS) adopts two load balancing strategies: hash and demand-driven. Taking account of the cost of termination detection, the execution time of the CPPS and simple hash method are estimated, and implement on an nCube2. The estimation meets the execution results. The CPPS provides much better load balance to improve scalability.

关键词： parallel production system multicomputer message-passing parallel computer load balancing

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ASYNCHRONOUS TRANSFER MODE (ATM) OPERATION VIA SATELLITE - ISSUES, CHALLENGES AND RESOLUTIONS

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 211-222页

作者： CHITRE, DM GOKHALE, DS HENDERSON, T LUNSFORD, JL MATHEWS, N COMSAT Laboratories 22300 Comsat Drive Clarksburg MD 20871 USA. Received his B.Sc. from the University of Bombay India an M.A. in mathematics from the University of Cambridge U.K. and a Ph.D. in physics from the University of Maryland. He is currently an Associate Executive Director of the Network Technology Division at COMSAT Laboratories. He has been involved in research and development activities in ISDN VSAT networks data communications and network systems and architectures. Prior to his current positions Dr. Chitre was a Principal Scientist in the Network Technology Division at COMSAT Laboratories. Dr. Chitre joined COMSAT Laboratories in 1980. He has made major contributions to the analysis and architecture of data communication ISDN and BISDN via satellite. Dr. Chitre directs and participates in the international and national standards activities in ISDN BISDN and data communication as they apply to satellite communication. He was Chairman of the Working Group on Protocols and Network Timing Function of the CCIR/CCITT Joint Ad Hoc Group on ISDN-Satellite Matters during 1990–1992. Currently he is the Chairman of the Working Group on New Technologies in the ITU Intersector Coordinating Group (ICG) on Satellite Matters. Dr. Chitre was a programme manager during 1990 and 1991 on a contract from INTELSAT on systems studies on satellite communications systems architectures for ISDN and broadband ISDN systems. Currently he is the technical manager of the DoD Contract on ATM via satellite demonstration and the programme manager for the INTELSAT contract on analysis and top-level specification of INTELSAT ISDN subnetworks and SDH compatible transport network. Department manager for ISDN/Data Communications in the Network Technology Division of COMSAT Laboratories. His responsibilities include managing the implementation of next generation telecommunication systems for fixed and mobile satellite systems. Current projects include the development of a high data rate gateway switch that provides for the

Key issues regarding the operation of the broadband integrated services digital network (BISDN) via satellite are presented herein. The specific issues, challenges, and their resolutions are detailed. In particular, the impact of error characteristics and propagation delay on the operation of BISDN via satellite is discussed. Solutions are presented for removing adverse effects and providing high-quality service to users of BISDN via satellite.

关键词： ATM BISDN

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HYBRID SATELLITE AND TERRESTRIAL NETWORKS

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 313-327页

作者： CHITRE, DM SHYY, DJ EPHREMIDES, A GUPTA, S COMSAT Laboratories 22300 Comsat Drive Clarksburg MD 20871–9475 USA. Received his B.Sc. from the University of Bombay India an M.A. in mathematics from the University of Cambridge U.K. and a Ph.D. in physics from the University of Maryland. He is currently an Associate Executive Director of the Network Technology Division at COMSAT Laboratories. He has been involved in research and development activities in ISDN VSAT networks data communications and network systems and architectures. Prior to his current positions Dr. Chitre was a Principal Scientist in the Network Technology Division at COMSAT Laboratories. Dr. Chitre joined COMSAT Laboratories in 1980. He has made major contributions to the analysis and architecture of data communication ISDN and BISDN via satellite. Dr. Chitre directs and participates in the international and national standards activities in ISDN BISDN and data communication as they apply to satellite communication. He was Chairman of the Working Group on Protocols and Network Timing Function of the CCIR/CCITT Joint Ad Hoc Group on ISDN/Satellite Matters during 1990–1992. Currently he is the Chairman of the Working Group on New Technologies in the ITU Intersector Coordinating Group (ICG) on Satellite Matters. Dr. Chitre was a programme manager during 1990 and 1991 on a contract from INTELSAT on systems studies on satellite communications systems architectures for ISDN and broadband ISDN systems. Currently he is the technical manager of the DoD Contract on ATM via satellite demonstration and the programme manager for the INTELSAT contract on analysis and top-level specification of INTELSAT ISDN subnetworks and SDH compatible transport network. Received the B.S. degree in electrical engineering from national Chiao-Tung University Hsin-Chu Taiwan in 1983 and the M.S. and Ph.D. degrees in electrical engineering from Georgia Institute of Technology Atlanta GA in 1986 and 1990 respectively. From June 1987 to October 1987 he worked for the Department of Neurology Emory Univers

The role of satellite communications in networks that provide new services, such as frame relay and multimedia, is investigated. Both passive and active (on-board switching/processing) satellite systems are considered. Novel techniques are developed for each system to demonstrate, via detailed analysis and simulation, how the communications bandwidth agility of multipoint/broadcast satellite channels, and the on-board switching/processing, makes it feasible to provide these new services via hybrid satellite and terrestrial networks in a resource-efficient manner.

关键词： HYBRID NETWORKS ON-BOARD processing FRAME RELAY

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