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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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ANALYSIS OF A MOVABLE BOUNDARY ACCESS TECHNIQUE FOR A MULTISERVICE MULTIBEAM SATELLITE SYSTEM

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 299-312页

作者： BOHM, S ELHAKEEM, AK MURTHY, KMS HACHICHA, M KADOCH, 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 . He is ITU's Specialist Consultant and Chief Advisor for a number of ITU/UNDP projects including VSATs Rural Networks Digital Broadc

In this paper, the performance of a new movable boundary accessing (MBA) technique for future integrated services multibeam satellite systems is studied. The multiservice environment considered includes both asynchronous and isochronous traffic consisting of video, voice, file transfer and interactive data. The movable boundary access technique proposed here will maximize the utilization of the up-link frame capacity. It is shown that the potential user population is substantially increased with the use of a moving boundary policy with minimal overhead.

关键词： MOVABLE BOUNDARY ACCESS TECHNIQUE MF-TDMA DAMA MULTIBEAM SATELLITE

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MODELING MULTISCALE SPATIAL ECOLOGICAL PROCESSES UNDER THE DISCRETE-EVENT SYSTEMS PARADIGM

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LANDSCAPE ECOLOGY 1993年第4期8卷 273-286页

作者： DEVASCONCELOS, MJP ZEIGLER, BP GRAHAM, LA Centro Nacional de Informaçäo Geográfica Lisboa Portugal Advanced Resource Technology Program Biosciences East room 203 The University of Arizona Tucson USA Department of Electrical and Computer Engineering The University of Arizona Tucson USA School of Renewable Natural Resources Room 203 Biosciences East The University of Arizona Tucson USA

A multi-scale spatial ecological model of a wet sclerophyllous forest subject to recurrent fires is presented. The model is specified in a Discrete Event Systems framework (DEVS) (Zeigler, 1990) interfaced with a Geographic Information System (GIS), and includes the ability to simulate landscape dynamics at several levels of resolution simultaneously. This is achieved by encoding a modular hierarchical representation of the forest landscape components into a set of nested, interconnected, and spatially referenced dynamic models. The results of the landscape dynamics simulations are displayed as sequences of maps through time, illustrating the potential of this modeling methodology for dealing with complex hierarchical structures that operate at several spatial and temporal resolutions.

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Guest Editorial: Focus on Digital Signal Processing Techniques Applied to Space Communications

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European Transactions on Telecommunications 1993年第1期4卷 9-10页

作者： Gaudenzi, Riccardo De Elia, Carlo Harris, Robert A. Rimrdo De Gaudend was born in Rosignano Mmo Italy in 1960. He received the Doctor En- gineer degree (cum Laude) in Electronic Engineering from the University of Pisa. Italy in 1985. From 1986 he was with the European Space Agency (ESA). Stsliow and Communications Engineering Department. Darmrtadt (RFA) where he was involved in satellite telecommunication ground systems design and testing. In particular he followed the development of two new ESA's satellite tracking systems. In 1988 be joined the ESA's Research and Technology Centre (ESTEC). Noordwijk. The Netherlands where is holding a position as releeommunication enginm in the Electrical System Department. He is presently responsible for the definition and development of advanced satellite communication systems. His mull intenst b ddyrducd with effacnt digital modulation and access techniques for fued and mobile wtdlite services synchronization topics and communication systems simulation techniques. Carlo Elia (S'89) was born in Trepuzzi. Italy in 1964. He received the Doctor Engineer degree in Electronic Engineering from Politecnico di Torino. Torino. Italy. in 1989. He his now attending a Doctorate program at PolitanieO di Torino. S i 1990. he has been with the Eurpean Space Agency (ESA) in the Electrical System Department as Tdeeommunications Syrtcm Engineer. His main areas of interest are related to rdvanccd digital modulation and access techniques and channel equalization. R.A. (Bob) Harris (S'69–M'70) received the PhD from the University of Southampton. England in 1971. In 1970 he joined the European Space Agency (then ESRO). based at the European Space Research and Technology Centre (ESTEC) Noordwijk. The Netherlandswas working on telemetry and telecommand systems. Since 1978 he has been Head of the Transmision Techniques Section in the Directorate of Telecom munications. He was involved in the transmission design of the OTS ECS Olympus and European Data Relay systems. He has worked on a wide range of analogue and digital transmission topics wit

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SHIPBOARD DAMAGED STABILITY ASSESSMENT - THE FLOODING CASUALTY CONTROL SOFTWARE

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NAVAL ENGINEERS JOURNAL 1993年第3期105卷 152-166页

作者： ZAHN, PB ROSBOROUGH, J CARLSTROM, R Peter B. Zahn:is a section chief in the Naval Architecture Department at Advanced Marine Enterprises. He is responsible for software development and special trials support. He has led the Flooding Casualty Control Software (FCCS) development effort since joining AME in 1989. He is also responsible for the material handling strikedown and stowage (MHS&S) software development program as well as special trials support for the ACVLAP and T-AGOS 19 programs. Prior to joining AME Mr. Zahn spent nine years with various companies of the ARCTEC Group. His experience includes field trials in venues from the Caribbean to the Bering Sea as well as model tests and engineering design and development efforts. Mr. Zahn received his B.S. in naval architecture and marine engineering from Webb Institute in 1980 and has published various papers on pollution prevention offshore systems and icebreaker design and performance. He is a member of ASNE and SNAME. John Rosborough:has been a naval architect for the Naval Sea Systems Command (NavSea) for the past 15 years. He is currently assigned to the Hydrodynamics Division with responsibility for aircraft carrier stability evaluations and as a task leader for computer-aided ship design development. In the Stability Division he was previously responsible for stability analyses on various amphibious ships SWATHs and foreign ships. He manages the upgrade and augmentation of SHCP at NavSea and is the Navy's technical point of contact for evaluating shipboard stability software and transitioning technology to the fleet. Mr. Rosborough received his B.S. in naval architecture and marine engineering from the University of Michigan in 1977. He is a member of USNI and the Association of Scientists and Engineers at NavSea. Richard Carlstrom:is a naval architect with Advanced Marine Enterprises. He has been responsible for software development in support of a variety of major programs including FCCS and SHCP and is a specialist in stability evaluations for complex ships such as CVs CVNs

The Flooding Casualty Control Software (FCCS) was developed under the auspices of the Naval Sea Systems Command (NavSea) and is currently being deployed on a variety of ships in the neets of both the U.S. Navy and the U.S. Coast Guard. The primary objective of FCCS is to enable damage control personnel to identify critical stability conditions, especially when related to the loss of reserve buoyancy due to battle damage and the destabilizing effects of large quantities of firefighting water, in a timely manner. FCCS was initially deploved in 1990. It utilizes the standard algorithms of the Ship Hull Characteristics program (SHCP). The user interface was designed to allow quick familiarity for shipboard users, primarily the damage control assistant (DCA) and his staff. Intact stability evaluations include the effects of topside icing, high winds, personnel crowding, heavy lifts over the side, high speed turns, and towing. FCCS also supports ballasting analysis for amphibious ships as well as providing bottom reaction and beached stability data for grounding incidents. Bv providing a tool for the ''fuel king'' and DCA to generate the required daily updates on the current ship load and liquids status, FCCS is assured of an accurate baseline in the event of damage. The design allows the evaluation of the ultimate ship stability status for a damage event using simple compartmentation and flooding status inputs. Evaluation of the adequacy of resulting stabilitv, as well as identification of such critical stability parameters as off center loading, margin line immersion, and negative GM, are accomplished by the program. Guidance is provided for the user to initiate appropriate flooding related damage control activities. Initially fitted on USS Oliver Hazard Perry Class frigates, FCCS databases have been for the USCG Hamilton class high endurance cutters, USS Arleigh Burke class Aegis destroyers, and a variety of other U.S. Navy and U.S. Coast Guard ship classes. The progra

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Data Point Reduction for NC Tool Path Generation on Over-Determined Data Set

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IFAC Proceedings Volumes 1992年第7期25卷 117-122页

作者： M. Yeung D. Walton Advanced Manufacturing Technology Program Institute of Mechanical Engineering National Research Council of Canada 435 Ellice Avenue Winnipeg Manitoba Canada R3B 1Y6 Department of Computer Science University of Manitoba Winnipeg Manitoba Canada R3T 2N2

Data acquired for object reproduction by laser or stereovision scanning processes are often over-determined. This causes problems in manufacturing processes, for example, NC tool path generation. Data reduction is a sensible solution to such problems. A heuristic method to reduce the data points with the user given tolerance is presented.

关键词： Data point reduction two axis scanner three axis scanner CNC tool path

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IMPROVING THE SHIP DESIGN, ACQUISITION AND CONSTRUCTION PROCESS

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NAVAL ENGINEERS JOURNAL 1992年第2期104卷 39-57页

作者： RYAN, JC JONS, OP J. Christopher Ryan:earned his bachelor's and master's degrees in Naval Architecture from Webb Institute and MIT respectively. He spent three years at the Advanced Marine Technology Division of Litton Industries working on the DD-963 class ship design and related computer aided design projects. he subsequently went to the Navy Department concentrating on early stage design of surface combatants for 12 years including work on the FFG-7 Sea Control Ship CSGN and CVV aircraft carrier projects. He then shifted focus and became the technical director for the Computer Supported Design Program in NavSea for five years. Mr. Ryan has served in several supervisory positions within the Ship Design Group in NavSea since that time. He is currently the project manager for the Ship Design Acquisition and Construction Process Improvement Project. Otto P. Jons:received a Diplom Ing. in shipbuilding from the Technical University of Hannover W. Germany and an M.S. in naval architecture and marine engineering from the Massachusetts Institute of Technology in 1967. He then joined Litton Ship Systems where he was responsible for the preliminary design of the DD-963 hull structure and then for ship systems as manager LHA Ship Systems Engineering Department. From 1972 to 1974 he was principal research scientist at Hydronautics. In 1976 as technical director he helped establish the local office of Designers and Planners. Otto Jons was one of the co-founders of Advanced Marine Enterprises Inc. in 1976 where he is corporate vice president engineering.

In the spring of 1990, the NavSea Chief Engineer initiated a project to improve the design, acquisition and construction (DAC) of U.S. Navy ships. The project's objectives are to reduce the time and cost of acquiring and operating Navy ships while improving their quality, unlike previous studies on the subject, the project utilizes a rigorous process analysis approach and attempts to use quantitative measures as the basis for recommending improvements. The paper is, of necessity, a status report on the progress of this project. Topics covered include: the DAC process;a look at the current state of ship acquisition time, cost, and quality;the methodology for process improvements;and early findings.

关键词： Naval Vessels

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Effects of aging on polyimide: a model for dielectric behavior (of relative humidity sensors)

Effects of aging on polyimide: a model for dielectric behavi...

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International Conference on Solid State Sensors and Actuators (TRANSDUCERS)

作者： A.R.K. Ralston M.C. Buncick D.D. Denton T.E. Boltshauser J.M. Funk H.P. Baltes Department of Electrical and Computer Engineering and Materials Science Program University of Wisconsin Madison Madison WI USA Physical Electronics Laboratory Swiss Federal Institute of Technology Zurich Switzerland

Quantifying the effect of moisture on the electrical properties of thin dielectric films requires the use of a model that takes into account the geometry of the test structure and the dielectric properties of the air layer above the device. Using this approach, it was found that the electrical properties of dry PI (polyimide) do not change substantially after six weeks of aging at 85 degrees C/85% RH (relative humidity). The dielectric permittivity of PI as a function of %RH increased with aging for excitation frequencies between 12 Hz and 100 kHz. This increase is correlated with observed changes in the surface chemistry of the aged PI film. Shifts in ESCA peak intensities indicate oxidation of the PI surface and deimidization with aging. Possible mechanisms for the observed changes in dielectric properties with aging include a change in the morphology of the bulk PI, resulting in a decreased surface to volume ratio, increased water absorption, a change in the interaction of absorbed water with the PI matrix, and dielectric interfacial effects.< >

关键词： Aging Polyimides Surface morphology Water Moisture Dielectric films Solid modeling Geometry Testing Dielectric devices

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FULL-WAVE SOLUTION OF DIELECTRIC LOADED WAVE-GUIDES AND SHIELDED MICROSTRIPS UTILIZING FINITE-DIFFERENCE AND THE CONJUGATE-GRADIENT METHOD

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INTERNATIONAL JOURNAL OF MICROWAVE AND MILLIMETER-WAVE computer-AIDED engineering 1991年第4期1卷 346-357页

作者： NARAYANAN, V MANELA, M LADE, RK SARKAR, TK Department of Electrical and Computer Engineering Syracuse University Syracuse New York 13244-1240 Viswanathan Narayanan was born in Bangalore India on December 14 1965. He received the BE degree in Electronics and Communications from B.M.S. College of Engineering Bangalore in 1988. He joined the Department of Electrical Engineering at Syracuse University for his graduate studies in 1989 where he is currently a research assistant. His research interests are in microwave measurements numerical electromagnetics and signal processing. Biographies and photos are not available for M. Manela and R. K. Lade. Tapan K. Sarkar (Sf69-M'76-SM'X1) was born in Calcutta. India on August 2 1948. He received the BTech degree from the Indian Institute of Technology Kharagpur India in 1969 the MScE degree from the University of New Brunswick Fredericton Canada in 1971. and the MS and PhD degrees from Syracuse University. Syracuse NY in 1975. From 1975-1976 he was with the TACO Division of the General Instruments Corporation. He was with the Rochester Institute of Technology (Rochester NY) from 1976-1985. He was a Research Fellow at the Gordon Mckay Laboratory Harvard University Cambridge MA from 1977 to 1978. He is now a Professor in the Department of Electrical and Computer Engineering Syracuse University. His current research interests deal with numerical solutions of operator equations arising in electromagnetics and signal processing with application to system design. He obtained one of the “ best solution” awards in May 1977 at the Rome Air Development Center (RADC) Spectral Estimation Workshop. He has authored or coauthored more than 154 journal articles and conference papers and has written chapters in eight books. Dr. Sarkar is a registered professional engineer in the state of New York. He received the Best Paper Award of the IEEE Transactions on Electromagnetic Compatibility in 1979. He was an Associate Editor for feature articles of the lEEE Antennas arid Propagation Sociefy Newsletter and was

Dynamic analysis of waveguide structures containing dielectric and metal strips is presented. The analysis utilizes a finite difference frequency domain procedure to reduce the problem to a symmetric matrix eigenvalue problem. Since the matrix is also sparse, the eigenvalue problem can be solved quickly and efficiently using the conjugate gradient method resulting in considerable savings in computer storage and time. Comparison is made with the analytical solution for the loaded dielectric waveguide case. For the microstrip case, we get both waveguide modes and quasi-TEM modes. The quasi-TEM modes in the limit of zero frequency are checked with the static analysis which also uses finite difference. Some of the quasi-TEM modes are spurious. This article describes their origin and discusses how to eliminate them. Numerical results are presented to illustrate the principles.

关键词： Waveguides

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ROLE OF SIMULATION IN RAPID PROTOTYPING FOR CONCEPT DEVELOPMENT

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NAVAL ENGINEERS JOURNAL 1991年第3期103卷 204-211页

作者： KING, JF BARTON, DE J. Fred King:is the manager of the Advanced Technology Department for Unisys in Reston Virginia. He earned his Ph.D. in mathematics from the University of Houston in 1977. He has been principal investigator of research projects in knowledge engineering pattern recognition and heuristic problem-solving. Efforts include the development of a multi-temporal multispectral classifier for identifying graincrops using LANDSAT satellite imagery data for NASA. Also as a member of the research team for a NCI study with Baylor College of Medicine and NASA he helped develop techniques for detection of carcinoma using multispectral microphotometer scans of lung tissue. He established and became technical director of the AI Laboratory for Ford Aerospace where he developed expert scheduling modeling and knowledge acquisition systems for NASA. Since joining Unisys in 1985 he has led the development of object-oriented programming environments blackboard architectures data fusion techniques using neural networks and intelligent data base systems. Douglas E. Barton:is manager of Logistics Information Systems for Unisys in Reston Virginia. He earned his B.A. degree in computer science from the College of William and Mary in 1978 and did postgraduate work in London as a Drapers Company scholar. Since joining Unisys in 1981 his work has concentrated on program management and software engineering of large scale data base management systems and design and implementation of knowledge-based systems in planning and logistics. As chairman of the Logistics Data Subcommittee of the National Security Industrial Association (NSIA) he led an industry initiative which examined concepts in knowledge-based systems in military logistics. His responsibilities also include evaluation development and tailoring of software engineering standards and procedures for data base and knowledge-based systems. He is currently program manager of the Navigation Information Management System which provides support to the Fleet Ballistic Missile Progr

A valuable technique during concept development is rapid prototyping of software for key design components. This approach is particularly useful when the optimum design approach is not readily apparent or several known alternatives need to be rapidly evaluated. A problem inherent in rapid prototyping is the lack of a "target system" with which to interface. Some alternatives are to develop test driver libraries, integrate the prototype with an existing working simulator, or build one for the specific problem. This paper presents a unique approach to concept development using rapid prototyping for concept development and scenario-based simulation for concept verification. The rapid prototyping environment, derived from artificial intelligence technology, is based on a blackboard architecture. The rapid prototype simulation capability is provided through an object-oriented modeling environment. It is shown how both simulation and blackboard technologies are used collectively to rapidly gain insight into a tenacious problem. A specific example will be discussed where this approach was used to evolve the logic of a mission controller for an autonomous underwater vehicle.

关键词： Military engineering

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