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CONCURRENT LARGE-SIGNAL SIMULATION OF AN ACTIVE MICROSTRIP ANTENNA

INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC networks DEVICES AND FIELDS 1995年第1期8卷 3-12页

作者： MCDOWALL, DS FUSCO, VF High Frequency Electronics Laboratory. Department of Electrical and Electronic Engineering The Queen's University of Belfast Ashby Building Stranmillis Road Belfast BT9 5AH U.K. D. Stewart McDowall was born in Dublin Republic 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 Departmnet 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 concurrent programming. He is an Associate Member of the Institute of Electrical Engineers. Vincent F. Fusco was educated at the Queens's University 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 telemetry systems. Currently he is a reader in Microwave Communications in the School of Electrical engineering and Computer Science the Queen's University of Belfast. His current research interests include non-linear microwave circuit simulatino 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.

This paper details the use of a circuit-based EM modelling technique combined with a harmonic balance simulator used to model the radiation from the microstrip bodies comprising an active antenna circuit. The modelling approach adopted for the planar bodies in the circuit will be shown to allow the use of concurrent algorithms in order to reduce overall computational time.

关键词： Microstrip antennas

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TECHNICAL ISSUES REGARDING SATELLITE PACKET-SWITCHING

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 257-267页

作者： IVANCIC, WD CHU, P SHYY, DJ National Aeronautics and Space Administration Lewis Research Center Cleveland Ohio 44135 USA. A design engineer in the Digital Technology Branch of the Space Electronics Division. He has extensive experience in satellite communications systems modulation and coding on-board switching and routeing and high speed digital design. Since joining NASA in 1982 Mr. Ivancic has been responsible for the development of a variety of matrix switch controllers ground terminal equipment numerous pieces of special test equipment a beacon controller for the SARSAT program (Search and Rescue Satellite) and a time-shared decoder for a processing satellite. In addition Mr. Ivancic has been technical contract monitor on a number of advanced communications technology contracts including the Advanced Modulation Technology Development a 5 GHz fibre-optic link and multi-programmable modem study. He was awarded the B.S.E.E. and M.S.E.E. degrees by Cleveland State University in 1982 and 1986 respectively. Cleveland State University Cleveland Ohio 44115 USA. Currently an assistant professor of Electrical Engineering Department at Cleveland State University. He obtained the M.S. and Ph.D. degrees from Iowa State University majoring in Electrical and Computer Engineering. His research interests include high-speed computer networks digital systems and neural networks applications. He is a member of Sigma Xi Phi Kappa Phi as well as the IEEE and ACM. ComSearch Reston Virginia 22091 USA. 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 University Atlanta as a Programmer. From September 1989 to December 1989 he worked for the Advanced Development Laboratory. AMP Inc. Atlanta as a Test Engineer. From February 1990 to August 1993 he wor

Many concepts for advanced communication satellite networks have recently been proposed. Critical technical issues relating to satellite packet switching for meshed very small aperture terminal networks and broadband ... 详细信息

关键词： FAST PACKET SWITCH BISDN MESHED VSAT ON-BOARD PROCESSING

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Fasciolosis in cattle in Louisiana. II. Development of a system to use soil maps in a geographic information system to estimate disease risk on Louisiana coastal marsh rangeland

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Veterinary Parasitology 1993年第1-2期47卷 51-65页

作者： Zukowski, Stanley H. Wayne Wilkerson, G. Malone Jr., John B. Department of Veterinary Microbiology and Parasitology School of Veterinary Medicine Louisiana State University Baton Rouge LA 70803 United States Computer-Aided Design and Geographic Information Systems Laboratory Louisiana State University Baton Rouge LA 70803 United States

A geographic information system (GIS) model of habitat for Lymnaea bulimoides, the snail intermediate host of Fasciola hepatica and the rumen fluke, Calicophoron microbothrioides, on the Chenier Plain of southwest Louisiana was revised to incorporate broad (greater than 100 m) chenier (relict beaches) along with adjacent marsh and transitional soils associated with spatial distribution of L. bulimoides habitat. The proportion of farmland comprised of soils of the GIS model coincided with actual habitat from a previous survey with a sensitivity of 91.3% and a specificity of 80.1%, and regressed significantly against the proportion of farmland comprised of L. bulimoides habitat (n = 12, P = 0.01, r² = 0.50, slope = 0.015). A soil model index was calculated to incorporate (1) the proportion of farmland comprised of soils of the GIS model and (2) stocking rate. Fluke egg shedding indices (mean egg count multiplied by prevalence) were calculated for each fluke species on nine farms at four sampling times over a 2-year period. The maximum egg shedding indices for each farm, taken to indicate potential fluke transmission intensity, were correlated for the two fluke species on herds not recently treated for fasciolosis (n = 9, P = 0.004, r² = 0.72, slope = 0.2), although at no one sampling period were shedding indices of the two fluke species significantly correlated. Egg shedding of C. microbothrioides by cattle correlated with the proportion of farmland comprised of soils included in the GIS model (n = 9, Spearman's rank coefficient was 0.7, P = 0.05). We conclude that (1) the maximum of several observations of the C. microbothrioides egg shedding index may be useful as a surrogate for F. hepatica in estimating risk from snail habitat on a farm when regular flukicide treatment interferes with F. hepatica egg shedding, and (2) the GIS model may estimate site-specific differences in fasciolosis risk to cattle operations in the Chenier Plain based on th

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A general solution to the harmonics summation problem

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European Transactions on Electrical Power 1993年第4期3卷 293-297页

作者： Lehtonen, M. Matti Lehtonen (1959) received his degrees of Master of Science and Licenciate of Technology both in electrical engineering from the Helsinki University of Technology HelsinkiEinland in 1984 and 1989 respectively. From 1984 to 1987 he was with the Consulting Company Ekono planning industrial power systems and developing computer aided design systems. Since 1987 he has been with Technical Research Centre of Finland. His main areas of interest are harmonics reactive power compensation ground fault protection and automation in electrical distribution networks. (Technical Research Centre of Finland Otakaari 7B SF-02 150 Espoo Finland T+3580/4566455 Fax +3580/4566538)

A general solution is presented for the probability density function of the amplitude of the sum of a number of harmonics from different sources. In the solution, the phase angles and amplitudes of component vectors may vary randomly in any given range. If these variation ranges are the same for all the component vectors, then ‐ in addition to them ‐ only arithmetic and geometric sums of the maximum amplitudes need to be known in order to calculate the parameters of the probability density function. Copyright © 1993 John Wiley & Sons, Ltd.

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ACSYNT - A standards-based system for parametric, computer aided conceptual design of aircraft

ACSYNT - A standards-based system for parametric, computer a...

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Aerospace design Conference, 1992

作者： Jayaram, S. Mykiebust, A. Gelhausen, P. Computer Aided Design Laboratory Virginia Polytechnic Institute and State University BlacksburgVA24061 United States Systems Analysis Branch NASA Ames Research Center Moffet Field CA94035 United States

A group of eight U. S. aerospace companies together with several NASA and NAVY centers, led by NASA Ames systems Analysis Branch, and Virginia Tech’s CAD laboratory agreed, through the assistance of American Technology Initiative, in 1990 to form the ACSYNT Institute. The Institute is supported by a Joint Sponsored Research Agreement to continue the research and development in computer aided conceptual design of aircraft initiated by NAS A Ames Research Center and Virginia Tech’s CAD laboratory. The result of this collaboration, a feature-based, parametric computer aided aircraft conceptual design code called ACSYNT, is described in this paper. The code is based on analysis routines begun at NASA Ames in the early ‘70’s. ACSYNT’s CAD system is based entirely on the ISO standard PHIGS and is graphics- device independent. The code includes a highly interactive graphical user interface, automatically generated Hermite and B-Spline surface models and shaded image displays. Numerous features to enhance aircraft conceptual design are described. © 1992 by the American Institute of Aeronautics and Astronautics, Inc.

关键词： NASA

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MULTIPLIER METHODS FOR ENGINEERING OPTIMIZATION

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING 1991年第7期32卷 1485-1525页

作者： ARORA, JS CHAHANDE, AI PAENG, JK Optimal Design Laboratory College of Engineering The University of Iowa Iowa City IA 52242 U.S.A. [?]Senior Engineering Systems Engineer Computer Aided Engineering Electronic Data Systems 750 Tower Dr. Troy MI 48007 U.S.A.

Multiplier methods used to solve the constrained engineering optimization problem are described. These methods solve the problem by minimizing a sequence of unconstrained problems defined using the cost and constraint functions. The methods, proposed in 1969, have been determined to be quite robust, although not as efficient as other algorithms. They can be more effective for some engineering applications, such as optimum design and control of large scale dynamic systems. Since 1969 several modifications and extensions of the methods have been developed. Therefore, it is important to review the theory and computational procedures of these methods so that more efficient and effective ones can be developed for engineering applications. Recent methods that are similar to the multiplier methods are also discussed. These are continuous multiplier update, exact penalty and exponential penalty methods.

关键词： Structural design

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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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CAD CAM MANUFACTURING OF PROTOTYPE SHIPBOARD COMPONENTS

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NAVAL ENGINEERS JOURNAL 1990年第3期102卷 93-99页

作者： CALVERT, TE RODRIGUEZ, FA SLEBZAK, JS Thomas E. Calvert P.E.: is a senior project engineer with the Propulsion and Auxiliary Systems Department David Taylor Research Center Annapolis Md. His interests include application of computers to all aspects of engineering with particular emphasis on utilization of small computers. Mr. Calvert is a licensed professional engineer in Maryland. He received a BSEE from Drexel University in 1969 and since that time has completed a number of graduate courses related to machinery acoustics. Francisco A. Rodriguez:is an engineer with the Propulsion and Auxiliary Systems Department David Taylor Research Center. He was formerly with the Computer-Aided Design/Interactive Graphics Group of the Division of Engineering and Weapons U.S. Naval Academy. His interests include interfacing the computer aided design to the computer aided manufacturing along with related software and hardware development. Mr. Rodriguez received a BSEEfrom the University of Virginia in 1968. James S. Slebzak:is a mechanical engineering technician with the Propulsion and Auxiliary Systems Department David Taylor Research Center. He received his machinists papers in 1971 after serving his apprenticeship at David Taylor Research Center. He continued his education and became the senior numerical control programmer at the Annapolis Laboratory. He completed his mechanical technology degree from Anne Arundel Community College in 1986. His interests are in the application of numerically controlled manufacturing techniques to prototype machinery components.

The machine shop at the Annapolis laboratory of the David Taylor Research Center (DTRC) provides model making and prototype support to a large variety of naval ship related engineering projects. In order to meet these challenging requirements, computer aided design/computer aided manufacturing (CAD/CAM) techniques are being used to produce “one of a kind” prototypes or very low volume production parts. The use of computer aides in these cases is to facilitate the accurate manufacture of a difficult part, rather than to improve manufacturing efficiencies. In addition, the approach provides the flexibility required to support research and development projects. Several examples of prototype shipboard components manufactured using CAD/CAM techniques are presented in this paper. The hardware and software that facilitated these projects are discussed. The examples described have met the requirements to produce a wide variety of prototype shipboard machinery components quickly and accurately.

关键词： Ship Equipment

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A computer INTEGRATED ENGINEERING SYSTEM FOR design AND LIFE-CYCLE MANAGEMENT

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NAVAL ENGINEERS JOURNAL 1986年第3期98卷 115-121页

作者： NICKODEMUS, GH YANUS, ID Irwin D. Yanusgraduated from the University of Pennsylvania with a bachelor's degree in arts and science in 1960 and a bachelor of science degree in mechanical engineering in 1961. In 1963 he received a master of science degree in mechanical engineering from Carnegie-Mellon University. Mr. Yanus is presently the manager of naval systems engineering in the Computer Aided Engineering Department of the Plant Engineering Division of Westinghouse Electric Corporation. His prior experience includes 19 years at the Bettis Atomic Power Laboratory where he performed assignments of increasing responsibility in design analysis development and procurement of nuclear reactor components for naval applications. As the manager of reactor mechanical design he was responsible for the mechanical design of theNimitzclass reactor components and control drive mechanism technology development. Mr. Yanus is a member of the American Society of Mechanical Engineers and the Society of Naval Architects and Marine Engineers. Glen H. Nickodemusgraduated from Michigan State University in 1964 with a bachelor of science degree in civil engineering. He joined the Pittsburgh-Des Moines Corporation in July of the same year. A master of science degree in civil engineering was obtained from Carnegie-Mellon University in 1973. In 1969 Mr. Nickodemus joined the Advanced Reactors Division of the Westinghouse Electric Corporation where he performed design and structural analysis functions for the development of the Fast Flux Test Facility and Clinch River Breeder Reactor Plant (CRBRP). As manager of CRBRP reactor engineering stress analysis he was responsible for the reactor vessel internals closure head control rod drivelines and miscellaneous guard vessels and head access area components. He is currently the manager of software development for the Computer Aided Engineering Department of the Plant Engineering Division. Mr. Nickodemus is a member of the American Society of Mechanical Engineers and is a registered professional engineer in Penn

This paper describes a computer integrated engineering system for design and life cycle management of weapons systems, ships and other multidisciplined systems. All engineering data are stored in a central engineering database. Individual application databases define and process information necessary for specific discipline evaluations. Interface modules between the application databases and the engineering database ensure that the entered data are complete, consistent, compatible, and in compliance with requirements. Conflicts are immediately identified and efficiently resolved. Implementation of the system improves design quality and reduces costs by minimizing the number of design iterations, reducing the effort to implement changes, providing effective storage and retrieval, and reducing the need for ship checks prior to modifications and alterations.

关键词： MILITARY ENGINEERING

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Some Extensions of the Open-Loop Balanced Approach for Model Reduction

Some Extensions of the Open-Loop Balanced Approach for Model...

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American Control Conference (ACC)

作者： J.M. Santiago M. Jamshidi Air Force Academy Colorado Springs CO USA Laboratory for Computer-Aided Design of Systems and Networks Department of Electrical and Computer Engineering University of New Mexico Albuquerque NM USA Department of Electrical Engineering Air Force Institute of Technology USA

This paper provides some extensions of a powerful open-loop model reduction technique called balanced realization. Developed by Moore, this approach uses concepts of controllability and observability to determine a reduced-order model. Moore's work was developed for controllable, observable, and asymototically stable systems. This paper shows that balancing techniques can be easily extended to unstable systems. Furthermore, using another model reduction method, called chained aggregation, the balanced and chained aggregation methods can be easily combined for systems that are also unobservable and uncontrollable.

关键词： Reduced order systems Symmetric matrices Control systems Matrix decomposition Observability Controllability Force control Eigenvalues and eigenfunctions Laboratories design automation

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