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PERFORMANCE OF A PRIORITIZED ON-BOARD BASEBAND SWITCH FOR A MULTISERVICE MULTIBEAM SATELLITE

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

作者： BOHM, 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-board baseband switch in conjunction with a multibeam satellite handling integrated services. The services considered for the analysis include voice, video, file transfer and interactive data. The prioritized switch uses both input and output buffering, switch speed-up as well as a two-phase head-of-line resolution algorithm, in order to reduce the buffer loss while maintaining acceptable user delays. The minimum required buffer 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 buffering and switch speed-up are needed even for the lowest priority users. The performance dependence on the switch size is also substantially reduced with head of line resolution and buffering even in a prioritized environment.

关键词： SWITCH ON-BOARD BASEBAND MULTIBEAM PRIORITIZED HEAD-OF-LINE UNIFORM LOAD SPEED-UP

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Dynamic bandwidth allocation in high speed integrated service networks

Dynamic bandwidth allocation in high speed integrated servic...

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IEEE Annual Joint Conference: INFOCOM, IEEE computer and Communications Societies

作者： P.P. Mishra S.K. Tripathi System Design and Analysis Group Department of Computer Science University of Maryland College Park MD USA

A threshold-based dynamic allocation policy, called DQT, in which the bandwidth allocated to each class of traffic is altered based on the queue occupancy at the end of a frame is studied. Two classes of traffic with different quality of service (QOS) requirements are considered, and it is shown that the performance of the proposed scheme is better than that of a static allocation scheme. The performance of the scheme and the parameter sensitivity are studied under both stationary and nonstationary conditions, and it is indicated how parameter values can be chosen.< >

关键词： Channel allocation Intelligent networks Intserv networks Quality of service Resource management Bandwidth Packet switching Switching circuits system analysis and design computer science

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An approach to the direct analysis of transient stability

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

作者： Djukanovic, M.B. Sobajic, 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 been intensely investigated over the last decade as a reliable and accurate tool for transient stability assessment of multimachine power systems. In this paper we propose the Potential Energy Boundary Surface (PEBS) based method for direct analysis of transient stability. The critical value of transient energy and the Critical Clearing Time (T_CCT) 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 based transient security assessment. The proposed approach is tested on the well‐known ten‐generator New England test system demonstrating the validity and accuracy of obtained results. Copyright © 1993 John Wiley & Sons, Ltd.

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DESIGNING FAULT TOLERANT APPLICATIONS IN MARUTI 3

DESIGNING FAULT TOLERANT APPLICATIONS IN MARUTI

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3RD INTERNATIONAL SYMPOSIUM ON SOFTWARE RELIABILITY ENGINEERING

作者： LIANG, DR AGRAWALA, A MOSSE, D SHI, YH System Design and Analysis Group Computer Science Department University of Maryland at College Park College Park 20742 MD United States

ISBN: (纸本)0818629754

In this paper, we introduce a model for developing applications with fault-tolerance requirements and real-time constraints. Applications in this model are specified using computation graphs, in which vertices represent tasks and arcs represent precedence constraints. Tasks are replicated to provide required fault tolerance and ensure that a real-time application will meet its deadlines despite failures. We develop an analytical model to calculate the probability of successful execution of applications with task replications. We propose an efficient algorithm for the analysis of applications that are composed of subgraphs, each of which has a single source and a single sink. The results of the analysis can be used with information from allocation/scheduling to develop applications with desired timing and fault-tolerance requirements. © 1992 IEEE.

关键词： Fault tolerance

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Integration of different system engineering methods using an object-oriented model

Integration of different system engineering methods using an...

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1992 Conference on Object-Oriented Programming systems, Languages, and Applications, OOPSLA 1992

作者： Clausen, Horst D. Hofmann, Anton Pawlitzek, Gabriele H. University of Salzburg Department of Computer Science and System Analysis Jakob-Haringer-Strasse 5 SalzburgA-5020 Austria German Aerospace Research Establishment Software Engineering Laboratory Munnchnerstrasse 20 OberpfaffenhofenD-8031 Germany

ISBN: (纸本)0897916107

The development of large, complex systems consisting of both hardware and software normally involves several companies and/or development teams for the development of the different subsystems forming the entire system. Depending on the kind of subsystem to be developed, these different development teams normally use different system engineering methodologies and/or tool sets to produce their subsystems. However, the usage of different methodologies and tools makes technical management and quality assurance for the entire development effort a difficult task. Therefore the development as well as the maintenance of future systems with their increasing size and complexity requires a common frame for the entire system development and maintenance effort covering different kinds of subsystems, like graphical user interfaces, database systems, expert systems, real-time systems, and so on. This common frame should support the separate and independent development of the different subsystems by different subcontractors using different system engineering methods, the integration of these subsystems to the entire system as well as the maintenance of the entire system. A hierarchical object-oriented model for the encapsulation and integration of different system engineering methods can serve as this common frame, providing traceability from the system requirements model to the implemented system while giving each subsystem development team full scope in choosing the system engineering method most suitable for a specific subsystem. The approach underlying this object-oriented model is the encapsulation of the different subsystems in "high-level objects," which can be either further decomposed into "high-level object" or described in more detail using any appropriate system engineering method. The integration of these "high-level objects" to the entire system is supported by a "definition object" on each layer of each system engineering model. The "definition objects" provide trace

关键词： Maintenance

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Designing fault tolerant application in Maruti

Designing fault tolerant application in Maruti

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International Symposium on Software Reliability Engineering (ISSRE)

作者： D. Liang A. Agrawala D. Mosse Yiheng Shi System Design and Analysis Group Computer Science Department University of Maryland College Park College Park MD USA

A model is given for developing application with fault-tolerance requirements and real-time constraints. Applications in this model are specified using computation graphs, in which vertices represent tasks and arcs represent precedence constraints. Tasks are replicated to provide required fault tolerance and ensure that a real-time application will meet its deadlines despite failures. The authors develop an analytical model to calculate the probability of successful execution of applications with task replications. They propose an efficient algorithm for the analysis of applications that are composed of subgraphs, each of which has a single source and a single sink. The results of the analysis can be used with information from allocation/scheduling to develop applications with desired timing and fault-tolerance requirements.< >

关键词： Fault tolerance Fault tolerant systems Resource management Application software Hardware Scheduling Educational institutions Real time systems Timing Redundancy

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Optimal end-to-end sliding window flow control in high-speed networks

Optimal end-to-end sliding window flow control in high-speed...

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International Phoenix Conference on computers and Communications (IPCCC)

作者： K.-T. Ko S.K. Tripathi Institute for Advanced Computer Studies and System Design and Analysis Group Department of Computer Science University of Maryland College Park MD USA

The performance of the end-to-end sliding window flow control mechanism on a single virtual circuit in the high-speed, wide-area network environment is investigated. The propagation delay is taken into consideration as the dominant delay in the analysis of the sliding window flow control mechanism. A closed queuing network is used to model a single virtual circuit in high-speed networks. Three different approaches are adopted which give similar results. By the influence of propagation delay, the optimal window size which maximizes the network power no longer depends on the number of nodes only, but also depends on the ratio of propagation delay to switch processing delay. The results show that the optimal window size still can be represented as a simple function of network parameters. These results are validated by simulation.< >

关键词： Optimal control Intelligent networks High-speed networks Switches Packet switching Propagation delay Protocols Optical packet switching computer networks Delay effects

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THE QUANTIFICATION OF INTEROPERABILITY

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NAVAL ENGINEERS JOURNAL 1989年第3期101卷 251-256页

作者： MENSH, DR KITE, RS DARBY, PH Dennis Roy Mensh:is currently the task leader Interoperability Project with the MITRE Corporation in McLean Va. He received his B.S. and M.S. degrees in applied physics from Loyola College in Baltimore Md. and the American University in Washington D. C. He also has completed his course work towards his Ph.D. degree in computer science specializing in the fields of systems analysis and computer simulation. He has been employed by the Naval Surface Warfare Center White Oak Laboratory Silver Spring Md. for 20 years in the areas of weapon system analysis and the development of weapon systems simulations. Since 1978 he has been involved in the development of tools and methodologies that can be applied to the solution of shipboard combat system/battle force system architecture and engineering problems. Mr. Mensh is a member of ASNE MORS IEEE U.S. Naval Institute MAA and the Sigma Xi Research Society. Robert S. Kite:is a systems engineer with the Naval Warfare Systems Engineering Department of the MITRE Corporation in McLean Va. Mr. Kite received his B.S. degree in electronic engineering from The Johns Hopkins University in Baltimore Md. Mr. Kite retired from the Federal Communications Commission in 1979 and served a project manager of the J-12 Frequency Management Support Project for the Illinois Institute of Technology Research Institute in Annapolis Md. before joining MITRE. Mr. Kite is presently a member of ASNE the Military Operations Research Society and an associate member of Sigma Xi. Paul H. Darby:has worked in the field of interoperability both in the development of interoperability concepts and systems since joining the Department of the Navy in 1967. He was the Navy's program manager for the WestPacNorth TACS/ TADS and IFFN systems. He is currently head of the Interoperability Branch Warfare Systems Engineering Office Space and Naval Warfare Systems Command. He holds a B.S. from the U.S. Naval Academy.

JCS Pub 1 defines interoperability as “The ability of systems, units or forces to provide services to and accept services from other systems, units or forces and to use the services so exchanged to enable them to operate effectively together.” With JCS Pub 1 as a foundation, interoperability of systems, units or forces can be factored into a set of components that can quantify interoperability. These components are: media, languages, standards, requirements, environment, procedures, and human factors. The concept described in this paper uses these components as an analysis tool to enable specific detailed analyses of the interoperability of BFC3 systems, units, or forces for the purpose of uncovering and resolving interoperability issues and problems in the U.S. Navy, Joint, and Allied arenas. Also, as a management tool, the components can help determine potential interoperability characteristics of future U.S. Navy BFC3 systems for compliance with battle force systems architectures. The approach selected for the quantification of interoperability was the development of a set of measures of performance (MOPs) and measures of effectiveness (MOEs). The MOPs/MOEs were integrated with a candidate set of components, which were used to partition the totality of interoperability into measurable entities. The methodology described employs basic truth table theory in conjunction with logic equations to evaluate the interoperability components in terms of MOPs that were aggregated to MOEs. It is believed that this concept, although elementary and based on fundamental principles, represents an operationally significant approach rather than a theoretical approach to the quantification of interoperability. The vehicle used as a means to measure the MOPs and MOEs was the Research Evaluation and systems analysis (RESA) computer modeling and simulation capability at the Naval Ocean systems Center (NOSC), San Diego, Calif. Data for the measurements were collected during a Tactical I

关键词： Military Engineering

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THE AEGIS DATA BUS EXPERIMENT

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NAVAL ENGINEERS JOURNAL 1989年第5期101卷 53-58页

作者： FRINK, JG VERVEN, DM John G. Frink is an assistant group supervisor in the Fleet Systems Department of The Johns Hopkins University Applied Physics Laboratory. He received his B.S. degree in physics from Michigan State University in 1968 and the M.S. degree in computer science from the University of Maryland in 1971. Mr. Frink worked at the Naval Surface Weapons Center White Oak Laboratory on a variety of weapons systems before joining the Applied Physics Laboratory in 1978. Mr. Frink has supervised the development of a large scale battle group simulation that successfully employs the receiver selection paradigm described herein on a hardware suite composed of an extensible number of (currently 15) processors. David M. Verven is a senior electrical engineer in the Fleet Systems Department of The Johns Hopkins University Applied Physics Laboratory. He received the B.S. degree in electrical engineering from the University of Maryland College Park in 1979 and the M. S. degree in the same discipline from The Johns Hopkins University in 1984. Mr. Verven joined the Applied Physics Laboratory in 1979 and initially worked on analysis of Navy sensor systems. In 1981 he was the AN/SPS-49 test team leader for the New Threat Upgrade (NTU) combat system land-based test. In 1982 he became involved in the development of the BBWRS system. Currently he is involved in real-time computer program development for the CEP project.

This paper documents an experiment performed by The Johns Hopkins University Applied Physics Laboratory to measure the effect of inserting a data bus into a combat system. The experiment was conducted at the Aegis computer Center located at the Naval Surface Weapons Center in Dahlgren, Virginia (NSWC/DL). The purpose of the experiment was to determine whether or not the Aegis Weapon system (the core of the Aegis Combat system) could be operated with a portion of its point-to-point interelement cables replaced by a data bus. The data bus chosen for the experiment employs message broadcasting with receiver selection. A primary goal of the experiment was to minimize the amount of Aegis computer program changes required to accommodate the data bus. The results presented in this paper will show that the experiment was a success. Key certification tests were passed with no computer program changes to the tactical elements and minimal changes in the Aegis tactical executive (ATES) program (less than 110 words changed).

关键词： Data Transmission Equipment

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AIR-CUSHION LANDING CRAFT NAVIGATION

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NAVAL ENGINEERS JOURNAL 1985年第4期97卷 248-260页

作者： GRAHAM, HR KIM, JC BAND, EGU FOWLER, AW Herbert R. Graham:received his degrees of B.S. in 1951 and M.S. in 1958 in aeronautical engineering from the Massachusetts Institute of Technology and the California Institute of Technology respectively. He also attended the Harvard Graduate School of Business Administration. He is presently a task manager at TRW Inc. McLean Virginia responsible for landing craft air cushion (LCAC) engineering support. Since joining TRW in 1967 he has had several technical project management and system engineering responsibilities in amphibious ships transportation and energy. He was responsible for the preliminary engineering design and cost estimates for tracked air cushion vehicles (TACVs). He has been active in several professional societies including ASNE and served as vice-chairman Los Angeles Section American Institute of Aeronautics and Astronautics. John C. Kim:received his degrees of B.S. in electrical engineering Tri-State University 1959 M.S. in electrical engineering Michigan State University 1960 and Ph.D. in electrical engineering Michigan State University. He is presently a senior staff engineer with TRW Inc. McLean Virginia where his technical experience has included communications system engineering and navigation system analysis. Since joining TRW in 1969 he has held numerous positions including section head project manager and department manager. His previous employment includes E-Systems/Melpar Division and Honeywell. Dr. Kim has been active in the IEEE Washington Chapter activities which included secretary vice-chairman and chairman of Systems Science and Cybernetics Group. Edward G.U. Band:received a B.S. degree in mechnical engineering in 1946 and a D.I.C in aeronautical engineering in 1947 at the City and Guilds College of London University. In 1951 he received an M.S. degree from Stevens Institute of Technology in fluid dynamics. After a career in the aircraft industry in England Canada and the U.S.A. he spent several years teaching in Chile and at Webb Institute of Naval Archi

Air cushion vehicles (ACVs) have operated successfully on commercial routes for about twenty years. The routes are normally quite short; the craft are equipped with radar and radio navigation aids and maintain continuous contact with their terminals. Navigation of these craft, therefore, does not present any unusual difficulty. The introduction of air cushion vehicles into military service, however, can present a very different picture, especially when external navigation aids are not available and the craft must navigate by dead reckoning. This paper considers the problems involved when navigating a high-speed air cushion vehicle by dead reckoning in conditions of poor visibility. A method is presented to assess the ACV's navigational capability under these circumstances. A figure of merit is used to determine the sensitivity of factors which affect navigation such as the range of visibility, point-to-point distance, speed, turning radius and accuracy of onboard equipment. The method provides simplistic but adequate answers and can be used effectively to compare the-capability and cost of alternative navigation concepts.

关键词： AIR CUSHION VEHICLES

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