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Asilomar Conference on Signals, systems & computers

作者： F. Harris B. Caulfield B. McKnight Systems Engineering Tiernan Communications Inc. San Diego CA USA Electrical and Computer Engineering College of Engineering San Diego State University San Diego CA USA Naval Research and Development Naval Command Control and Ocean Surveillance Center San Diego CA USA

The standard sigma-delta modulator uses feedback around 1-bit quantizers to transform open loop integrator poles into closed loop transmission zeros of the noise transfer function. The DC transmission zeros permit high resolution quantization of data over a frequency band in their neighborhood. Closed loop zeros can be shifted to arbitrary spectral locations by doubling the number of integrators and then applying local feedback around integrator pairs thereby converting them to resonators. These spectrally shifted zeros support high resolution quantization at the selected (arbitrary) center frequency. In the paper the authors describe an alternate technique for shifting the open loop poles around the unit circle. In this method, rather than forming resonators, they use a spectral transformation on the baseband process performed by embedded all-pass filters.< >

关键词： Frequency Delta-sigma modulation Feedback loop Filtering theory Quantization Poles and zeros Transfer functions Baseband Resonator filters

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Prediction and comparisons of C-band reflectivity profiles from S-band dual polarization measurements

Prediction and comparisons of C-band reflectivity profiles f...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： H. Direskeneli T.A. Seliga K. Aydin Information and Control Systems Inc. Hampton VA USA Electromagnetics and Remote Sensing Laboratory Department of Electrical Engineering University of Washington Seattle WA USA Communications and Space Scienceences Laboratory Department of Electrical and Computer Engineering Pennslyvania State University University Park PA USA

Apparent reflectivity factors measured by a radar operating at an attenuating wavelength can be adequately predicted by using the reflectivity factors at horizontal and vertical polarizations measured at a non-attenuating wavelength. This capability is important for understanding effects of rainfall on both microwave communication systems and the operation of weather radars operating at attenuating wavelengths. This paper examines and tests this capability by using S-band dual polarization radar measurements to predict C-band radar reflectivity measurements of the same storm but from a different location. The predictions of C-band observations were obtained from disdrometer-derived relationships between S-band reflectivity factor Z/sub H/(10 cm) and differential reflectivity Z/sub DR/ measurements and C-band reflectivity factor Z/sub H/(5 cm) and specific attenuation A/sub H/. Apparent reflectivity factor measurements at C-band, derived from S-band measurements, compared very well with actual measurements in the same storm. The results support the use of the dual polarization radar technique for predicting scattering and attenuation effects of narrow beam microwave signals propagating through rain-filled media along paths other than that traversed by the radar.< >

关键词： Reflectivity Attenuation measurement Wavelength measurement Radar measurements Polarization Radar scattering Storms Microwave communication Meteorological radar Testing

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Worst Case Identification of Continuous time systems via Interpolation

Worst Case Identification of Continuous time Systems via Int...

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American control Conference (ACC)

作者： Jie Chen Guoxiang Gu Carl N. Nett Schools of AeroSpace and Electrical Engineering Georgia Institute of Technology Atlanta GA USA Department of Electrical and Computer Engineering Louisiana State University Baton Rouge LA USA Laboratory for Identification and Control of Complex Highly Uncertain Systems(LIC-CHUS) School of Aerosapce Engineering Georgia Institute of Technology Atlanta GA USA

We consider a worse case control oriented identification problem recently studied by several authors. This problem is one of the H∞ identification in the continuous time setting. We give a less conservative formulation of this problem. The available apriori information consists of a lower bound on the relative stability of the plant, a frequency dependent upper bound on a certain gain associated with the plant, and an upper bound on the noise level. The available experimental information consists of a finite number of noisy plant point frequency response samples. The objective is to identify from the given apriori and experimental information an uncertain model that includes a stable nominal plant model and a bound on the modeling error measured in H∞ norm. Our main contributions include both a new identification algorithm and several new explicit lower and upper bounds on the identification error. The algorithm proposed belongs to the class of interpolatory algorithms which are known to possess a desirable optimality property under a certain criterion. The error bounds presented improve upon the previously available ones in both the aspects of providing a more accurate estimate of the identification error as well as establishing a faster convergence rate for the proposed algorithm.

关键词： Continuous time systems Interpolation Upper bound control systems Frequency Convergence Sampling methods Stability Noise level System identification

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NAVAL SURFACE COMBATANT SHIP DESIGNERS AID

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NAVAL ENGINEERS JOURNAL 1993年第3期105卷 70-77页

作者： ANDERT, EP The Author:has over 14 years' experience in computer systems development and analysis including naval applications intelligent systems parallel processing signal processing and real-time systems. As vice president of Conceptual Software Systems Inc. he leads software development activities. He is the principal investigator on the development of an automated ship designer's aid automated naval ship producibility tools parallel processing software tools computer-aided software engineering tools and neural networks for sensor data processing. Previously Mr. Andert worked on a data analysis expert system for naval missile tracking the FAA air-traffic control system satellite sensor data processing and the SQS-53 sonar beam-former. Mr. Andert received a B.A. degree and an M.S. in computer science from California State University Fullerton. He has published more than 15 articles on computing in various technical journals books and proceedings.

The naval surface combatant ship design process can be greatly enhanced by a computerized, knowledge-based designer's aid. Naval surface ship design is a technological challenge to maximize ordnance on target which requires the use of rapidly advancing techniques and systems for surveillance, detection, communication, information processing, ordnance deliverv, and propulsion, among others. This paper discusses the first step in the development of a computerized, knowledge-based (expert svstem) tool to assist ship designers in selecting requirements and incorporating the most appropriate combat svstems and certain hull, machinery and electrical system (HM&E) equipment. This Naval Surface Combatant Ship Designer's Aid (NAVSURF) svstem allows the designer to select the type of ship to be developed and required ship characteristics such as speed. It then suggests a set of requirements for the ship along with a set of combat and HM&E equipment based on the selected requirements. The NAVSURF svstem is an interactive environment that suggests requirements and equipment while allowing the user to select alternatives, ask for reports of selected items, upgrade the databases of available requirements, and upgrade the knowledge-base that makes suggestions.

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Development and integration of an equation-solving program for engineering thermodynamics courses

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computer Applications in engineering Education 1993年第3期1卷 265-265页

作者： Klein, S.A. Mechanical Engineering Department University of Wisconsin-Madison 53706 Dr. S. A. Klein:is a professor of Mechanical Engineering at University of Wisconsin-Madison. His engineering degrees (BS University of Illinois-Chicago MS PhD University of Wisconsin-Madison) were obtained in Chemical Engineering. Professor Klein is a member of the Solar Energy Laboratory at Wisconsin. He is the developer of the F-Chart method for sizing solar heating systems and the TRNSYS simulation program which is widely used in simulations of solar processes. Currently Professor Klein is involved in research on solar energy system performance absorption power cycles finite-time thermodynamics applications adsorption processes for air conditioning and air quality control and alternative refrigerants and systems for refrigeration and air conditioning applications. Professor Klein is also involved in the development of engineering computer tools for both instruction and research. In addition to the EES program described in this paper he is the primary author of the thermodynamics instructional program CP/Thermo and the finite element program FEHT.

Thermodynamics problems can be separated into conceptual and mathematical parts. The conceptual part consists of the problem formulation and analysis. The mathematical part seeks to obtain an answer to a problem by solving the equations identified in the analysis. The mathematical part can be complex and time-consuming and often directs the students' focus away from the concepts. An equation solving program called engineering Equation Solver (EES) was developed to reduce the time and effort required by students to solve the mathematical part of thermodynamics problems. EES differs from existing equation solving programs in that it is designed for use by students and it includes an extensive library of built-in functions for thermodynamic and transport properties of fluids. Thermodynamic and transport property data needed for solving engineering problems (eg, steam tables, refrigerant properties, psychrometric and combustion gas data) are built into the program. By eliminating table lookups and algebra, EES allows students to concentrate on engineering fundamentals, as well as to do more complex design problems.

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Steady‐state modelling of a uniform pulse‐width modulated single‐phase AC‐to‐DC converter‐fed DC motor drive

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European Transactions on Electrical Power 1993年第5期3卷 379-386页

作者： Hamed, S.A. Dr. Sadeq A. Hamed (1957) received his B.Sc. degree in Electrical Power Engineering from Damascus University Syria in 1980. From 1980 to 1982 he has been with the Department of Electrical Engineering at the University of Jordan Ammad/Jordan. He obtained the M.Sc. degree in Power Electronics and Systems and the PhD degree in Power Electronics from the University of Manchester Institute of Science and Technology (UMIST) Manchester/GB in 1983 and 1986 respectively. In 1986 he joined the Department of Electrical Engineering. Jordan University as an Assistant Professor. In 1991 became an Associate Professor at the same department. His research activities include modelling and simulation of AC/DC drive systems pulse-width modulation control of motor implementation of computer-controlled drive systems energy saving in the electrical drive industry. (Jordan University Department of Electrical Engineering Amman/Jordan T + 96 26/843555 - 28 13 Fax + 9626/8485 58)

With the increasing availability of power transistor switches, PWM controlled rectifiers can efficiently and economically be employed in low and medium power applications of DC drive systems. In this paper, steady‐state modelling and solution of a uniform pulse‐width modulated single‐phase AC‐to‐DC converter‐fed DC motor drive is accomplished. The developed model is presented in a generalized form that is applicable irrespective of the number of pulses per supply half‐cycle. Measured and predicted parameters are shown to be very close and the model is proved to be efficient and accurate. Both continuous and discontinuous modes of operation are covered, and critical operating conditions at which the system moves from one mode to the other are thoroughly investigated. The effects of the armature inductance‐to‐resistance ratio and the chopping frequency on these critical conditions, load and line harmonics, and on the ripple contents of the armature current are also thoroughly investigated. Copyright © 1993 John Wiley & Sons, Ltd.

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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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QUALITY MANAGEMENT AND MASTER ORDNANCE REPAIR

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NAVAL ENGINEERS JOURNAL 1993年第5期105卷 68-76页

作者： STIMSON, WA MARTINEZ, E William A. Stimson:received his B.S. degree in mathematics from the University of Texas at El Paso in 1964 and his M.S. degree in engineering from the University of Santa Clara in 1971. Mr. Stimson was employed in the aerospace industry for ten years then joined the Naval Ship Weapon Systems Engineering Station in Port Hueneme Calif in 1973. At NSWSES he served ten years as a ship qualification trials project supervisor and seven years as program manager of the Master Ordnance Repair Program. Today Mr. Stimson lives in Charlottesville Va. and is a Ph.D candidate in systems engineering at the University of Virginia majoring in quality management and statistical quality control. Ernest Martinez:received his B.S. degree in computer sciences from National University in 1985. Mr. Martinez was head of combat systems at the Naval Ship Repair Facility Yokosuka Japan for five years returning in 1983 to the Naval Sea Support Center Pacific San Diego Calif. During the next five years he managed the Fleet Modernization Program and was coordinator of the Combat System Readiness Test Program. Today Mr. Martinez lives in San Diego and is employed by the Naval Surface Warfare Center Port Hueneme Calif. as MOR program manager.

Because of the redefinition of national defense needs and the reduction of defense budgets, the management of complex combatant repair is more imperative than ever. To this end, the U.S. Navy is calling for Total Quality Leadership (TQL) strategies from its agencies and contractors. These strategies are derived from well known initiatives of quality management, such as those of Deming. They define the basis of any quality program. Quality methodologies have proven highly effective in the manufacturing sector, but many remain unproven or tentative in service and repair industries. The authors believe that TQL methods can be effective in the repair industry also, but must be developed or adapted to suit the unique characteristics of that industry: high skill, non-rote crafts, with continual customer interface at all levels of operation. In establishing a direction for TQL development, the authors have chosen two elements. The first is the Malcolm Baldrige Quality Improvement Program, which provides guidelines for direction. The second is the Master Ordnance Repair (MOR) Program, which provides the management vehicle. From its beginning in 1983, MOR has been a program of management. The task is explicit in its charter, NAVSEAINST 8000.2, which requires that a MOR contractor manage combat system work and testing. Quality management methods are applied to the MOR program to achieve MOR objectives using Baldrige measurements. Methods are presented which deploy the quality function across the organization. Techniques are provided to improve the company's ability to control its processes and the robustness of its product. These include methods of process analysis that determine added value, ownership, and internal customer. Stress is placed on in-process verification rather than on end-of-process inspection. The recommendations of this paper require no extraordinary skills or costs, but do require a formal and systematic approach to quality issues. The authors believe that

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ACCURACY REQUIREMENTS FOR MEASUREMENT systems WITH UNIFORM AND NORMAL ERRORS

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NAVAL ENGINEERS JOURNAL 1993年第1期105卷 66-69页

作者： SNOW, JM STUCKMAN, BE USHER, JS Jeffrey M. Snow:received his B.S. degree in mechanical engineering from the University of Washington in 1977. He has worked at Boeing Commercial Aircraft Company and Puget Sound Naval Shipyard. Since 1985 he has been at Naval Surface Warfare Center Crane Division (NSWCC). From 1987 to 1990 he was in charge of quality assurance configuration management and reliability for Aegis (SPY-1 and Mk-99) microwave tubes. He currently is in the Radar System Branch at NSWCC. He is a member of ASQC and ASME. His areas of interest include the use of statistics in process improvement efforts and objectively rating and rewarding suppliers for better quality. Bruce E. Stuckman:holds a Ph.D. degree in systems engineering from Oakland University where he also obtained M.S. and B.S. degrees in electrical and computer engineering. In 1992 Dr. Stuckman obtained his J.D. from the University of Louisville where he graduated cum laude. He is currently an associate in the patent and computer law department of Brooks & Kushman a law firm specializing in intellectual property and technology related causes. Prior to this he was an associate professor of both electrical engineering at the University of Louisville and a member of the Research Advisory Board of the South Central Bell Telecommunications Research Center. Dr. Stuckman is the author of over 75 published works in a variety of research areas including global optimization algorithms control systems communication and telecommunication systems and instrumentation electronics. He has served as a technical consultant to such organizations as Control Data Corporation General Electric General Motors Research Laboratories Gulf & Western AT&T Bell Laboratories ARCO Research and Technical Services and the U.S. Government and has been a frequent lecturer at national and international symposia. He is a senior member of IEEE and a member of ASNE Eta Kappa Nu Tau Beta Pi Sigma Xi and Phi Kappa Phi. John S. Usher Ph.D. P.E.:is an assistant professor of industrial engineering

Accuracy requirements are usually determined as a percentage of the specification range of the measured part or process. Setting accuracy requirements in this manner results in a wide and unpredictable range of false rejection and acceptance probabilities. This causes extra costs due to either: 1) over specification of measurement systems accuracy requirements;2) time, effort, retesting, and resolution of false rejections;or 3) system degradation caused by false acceptance of out-of-specification parts. Achieving a consistent and known risk of false acceptance is only possible by considering the measured process C(pk), the process's mean in relation to the center of the specification range, and the measurement system error distribution. This paper presents a method for calculating the probabilities of false rejection and false acceptance for a normal process which is measured with, alternately, uniform and normally distributed error. It is shown that under most conditions uniform error causes 20% to 30% higher false rejection and acceptance probabilities. Thus, knowledge of measurement error distribution could provide lower total production cost.

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computer‐aided calculation of the steady‐state thermal performance characteristics of low‐voltage circuit breakers

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European Transactions on Electrical Power 1993年第5期3卷 347-352页

作者： Völker, F. Dr.-Ing. Frank Völker (1958) VDI studied mechanical engineering special subjects “powerengineering automatic control engineering and mechanical science” at the University-GH-Duisburg/Germany where he got his Dipl.-Ing. degree in 1984. From 1984 to 1990 he has been a scientific assistant at the department “Konstruktionslehre und Fördertechnik” special subject “computer simulation of the performance characteristics of driving systems” at the same University where he received his Dr.-Ing. degree in 1990. In 1990 he joined Klöckner-Moeller GmbH Bonn/Germany as research engineer at the department “Forschung”. Since 1992 he is manager of Energy Management Systems at this company. (Klöckner-Moeller GmbH Head Office Energy Management Systems Hein-Moeller-Str. 7-11 D-53115 Bonn T +49228/602 - 11 62 Fax +49228/602- 11 94)

A discrete thermal network is given as an equivalent circuit of the steady‐state thermal performance characteristics of circuit breakers. The immediate environment of the enclosure and the feeders of the unenclosed switching device are the boundaries of the equivalent circuit, which specifically models the central phase of a three‐phase circuit breaker. computer simulations make it possible to analyse the thermal system performance in rated service. Selected examples prove the high quality of the model and the efficiency of the described method of calculation. Copyright © 1993 John Wiley & Sons, Ltd.

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