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Asilomar Conference on Signals, Systems & computers

作者： F. Harris B. Caulfield B. McKnight College of Engineering Electrical & Computer Engineering San Diego State University San Diego CA USA Naval Command Control and Ocean Surveilance Center Naval Research and Development Service San Diego CA USA

This paper presents and compares the structure and performance of new alternate architectures developed for spectral noise shaping in over-sampled analog-to-digital and digital-to-analog converters. These architectures differ from conventional design approaches in two ways. The primary difference is in the distribution of transmission zeros in the noise transfer function, while the secondary difference is the manner in which the architecture forms these transmission zeros.< >

关键词： Noise shaping Filtering theory Digital-analog conversion Transfer functions

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Adaptive interference suppression for CDMA based PCN systems

Adaptive interference suppression for CDMA based PCN systems

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IEEE International Conference on Communications (ICC)

作者： P. Wei T. Soni J.R. Zeidler W.H. Ku P.K. Das Department of Electrical and Computer Engineering University of California San Diego La Jolla CA USA R.d.t. & E. Division Control and Ocean Surveillance Center San Diego CA USA Department of Electrical Computer Engineering University of California San Diego La Jolla CA USA

A number of different techniques for the suppression of narrowband interference due to overlay in code division multiple access (CDMA) systems have previously been studied. The relative performances of three such techniques for a fading channel, multi-user CDMA system are described. Personal communication network systems using suppression filters based on the transversal least mean square (LMS) and the lattice and transform domain algorithms are studied. Bit error rates are found by simulations for different suppression filters. The overlay signal is assumed to be narrowband binary phase shift keying (BPSK) and the performance of these systems is studied for varying BPSK carrier frequency offsets. Since both the lattice and LMS filters converge to the Wiener filter, their relative performance is also studied during the on/off transient of the interference. It is found that the LMS and recursive least square (RLS) perform similarly under stationary interference. The RLS is less susceptible to changes in the interference due to its faster convergence.< >

关键词： Interference suppression Multiaccess communication Personal communication networks Least squares approximation Wiener filter Binary phase shift keying Narrowband Transversal filters Lattices Resonance light scattering

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A network approach to parallel discrete event simulation

A network approach to parallel discrete event simulation

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Annual Conference of AI, Simulation, and Planning in High Autonomy Syslems

作者： S.T. Chang L.J. Peterson P.C.-Y. Sheu Department of Electrical and Computer Engineering Rutgers University Piscataway NJ USA RDT&E Division Naval Command Control and Ocean Surveillance Center San Diego CA USA

A network approach to parallel discrete event simulation is described. A set of production rules is used to describe the behavior of active objects in a simulation system so that production rules can be merged and evaluated collectively in a rule network. To maintain correctness and exploit all possible parallelism, each token is time-stamped and can be processed asynchronously. To handle rollbacks, a lazy cancellation approach is used.< >

关键词： Discrete event simulation Object oriented modeling Production systems Computational modeling Constraint optimization Parallel processing Operating systems control system synthesis Oceans Surveillance

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Rapid Retargetting of a Flexible Pointing System with Structure Mounted Sensors and Actuators

Rapid Retargetting of a Flexible Pointing System with Struct...

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American control Conference (ACC)

作者： Farshad Khorrami Sandeep Jain M. Mattice N. Coleman Control/Robotics Research Laboratory School of Electrical Engineering El Computer Science Polytechnic University Brooklyn NY USA Development and Engineering Center Automation and Robotics Team U.S. Army Armament Research Picatinny Arsenal NJ USA

In this paper, active control of flexible structures through utilization of structure mounted sensors and actuators is considered. Specifically, dynamic feedback design utilizing signals from the accelerometer mounted on the structure is discussed. Furthermore, utilization of piezoceramics for sensing and actuation to provide a higher level of control for vibration damping is investigated. The flexible pointing system considered here is the test-bed at the Army Research Development engineering center (ARDEC), which is a scaled-down representation of real-life targetting systems. This setup is also a nice benchmark problem for system identification and different control design philosophies. The approaches advocated here are based on Youla's parametrization of stabilizing controllers, Wiener-Hopf design and decentralized frequency shaping. Modelling aspects for the setup, taking all the structural intricacies into account, are discussed. The preliminary results indicate a significant improvement in performance through utilization of these control schemes.

关键词： Sensor systems Actuators Flexible structures Feedback Signal design Accelerometers Piezoelectric materials Vibration control Damping System testing

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Use of allpass networks to tune the center frequency of sigma delta modulators

Use of allpass networks to tune the center frequency of sigm...

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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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ISAR imaging of an airborne DC-9 (aircraft)

ISAR imaging of an airborne DC-9 (aircraft)

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1993 IEEE International Conference on Acoustics, Speech, and Signal Processing

作者： M. Soumekh S. Nugroho S. Jones R. Rysdyk S. Tran Department of Electrical & Computer Engineering State University of New York University at Buffalo Amherst NY USA RDT&E Division Naval Command Control and Ocean Surveillance Center San Diego CA USA

The authors discuss the use of realistic ISAR (inverse synthetic aperture radar) data for an airborne DC-9 to exhibit some of the difficulties associated with processing ISAR data and interpretation of a reconstructed ISAR image. They consider methods to address these issues that are based on ISAR signature spectral properties of a moving target. In particular, they show the utility of spatial Doppler (slow-time Doppler) processing ISAR data in the target's velocity and acceleration estimation and its image formation. They present a method for reducing coherent speckle via separating the dominant reflector signature in the compressed ISAR signal. As a result, more details about the aircraft can be extracted from the ISAR data. Reconstruction results for various phases of the DC-9's flight path are presented.< >

关键词： Aircraft High-resolution imaging Synthetic aperture radar Image reconstruction Speckle Image databases Gold Acceleration Radar antennas Radar imaging

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Global robustness of nonlinear systems to state measurement disturbances

Global robustness of nonlinear systems to state measurement ...

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IEEE Conference on Decision and control

作者： R.A. Freeman P.V. Kokotovic Center for Control Engineering and Computation Department of Electrical and Computer Engineering University of California Santa Barbara CA USA University of California Santa Barbara Santa Barbara CA US Dept. of Electr. & Comput. Eng. California Univ. Santa Barbara CA USA

We consider nonlinear control systems for which an estimate x/spl circ/ of the system state x is available for feedback. We assume x/spl circ/=x+d/sub m/, where d/sub m/(t) is an unknown locally bounded state measurement disturbance. We present conditions under which we can design a smooth feedback law u=/spl mu/(x/spl circ/) which renders the mapping from d/sub m/ to x globally input/output stable. For any initial condition, such a feedback law will guarantee that no finite escape times occur, that bounded disturbances d/sub m/ produce bounded signals, and that x/spl rarr/0 when d/sub m//spl rarr/0. We show that the class of systems for which such feedback laws exist include systems in strict feedback form. One important application is in the output feedback stabilization problem, where the disturbance d/sub m/ comes from a separately designed observer.< >

关键词： Nonlinear systems control systems Output feedback State feedback Radio control Stability control engineering control engineering computing Noise robustness Robust control

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A parallel VLSI implementation of Viterbi algorithm for accelerated word recognition

A parallel VLSI implementation of Viterbi algorithm for acce...

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Great Lakes Symposium on VLSI

作者： V. Upadhyaya S.J. Upadhyaya A. Kundu Dept. of Electr. & Comput. Eng. State Univ. of New York Buffalo NY USA Department of Electrical and Computer Engineering State University of New York University at Buffalo Buffalo NY USA Naval Command Control and Ocean Surveillance Center San Diego CA USA

A hardware VLSI implementation of the Viterbi algorithm is presented. The Viterbi algorithm is used to solve a word recognition problem using a hidden Markov model. In order to accelerate the speed of computation for real-time word recognition, the inherent parallelism in the recursion step of the algorithm is exploited. Details of the hardware implementation and experimental results are discussed.< >

关键词： Very large scale integration Viterbi algorithm Acceleration Hidden Markov models Handwriting recognition Hardware Parallel processing Tail Pipelines Text recognition

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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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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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