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EARLY ORIENTATION SELECTION—INFERRING TRACE, TANGENT, AND CURVATURE FIELDS

International Journal of Pattern Recognition and Artificial Intelligence 1988年第3期2卷 443-457页

作者： STEVEN W. ZUCKER Canadian Institute for Advanced Research Computer Vision and Robotics Laboratory Department of Electrical Engineering McGill University Montréal Québec Canada

Orientation selection is the inference of orientation information out of images. It is one of the foundations on which other visual structures are built, since it must precede the formation of contours out of pointillist data and surfaces out of surface markings. We take a differential geometric view in defining orientation selection and develop algorithms for actually doing it. The goal of these algorithms is formulated in mathematical terms as the inference of a vector field of tangents (to the contours), and the algorithms are studied in both abstract and computational forms. They are formulated as matching problems, and algorithms for solving them are reduced to biologically plausible terms. We show that two different matching problems are necessary, the first for 1-dimensional contours (which we refer to as Type I processes) and the second for 2-dimensional flows (or Type II processes).

关键词： computer vision Orientation selection Curve detection Relaxation Edge detection Texture

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Board-level diagnosis by signature analysis

Board-level diagnosis by signature analysis

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IEEE International Test Conference

作者： M.G. Karpovsky P. Nagvajara Research Laboratory for Design and Testing of Computer and Communication Systems Computer and Communication Systems Computer and Communication Systems Department of Electrical Computer and System Engineering Boston University Boston MA USA

Board-level diagnostic techniques by signature analysis based on single-error-correcting Hamming codes over GF(2/sup M/) (where M is the number of outputs per chip) are presented. Two techniques are considered: the space-time compressor technique for the case when responses from N chips on the board are wired to the compressor; and the time compressor technique for the case when test responses from each chip are transferred to the compressor via system bus. Assuming a single-faulty-chip model, a faulty chip on the board under test is located by an analysis of the relationship between the distortions in the obtained signatures. Both techniques for board-level diagnosis require less hardware than the straightforward diagnostic techniques using a built-in signature analyzer for every chip or selective testing of each chip via the system bus, hence offering an efficient approach for a design of a built-in-self-test board for for manufacturing testing.< >

关键词： System testing System buses Hardware Built-in self-test Automatic testing Pattern analysis Fault diagnosis Laboratories Design engineering systems engineering and theory

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A Topological Global Routing Algorithm For General Cells

A Topological Global Routing Algorithm For General Cells

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Asilomar Conference on Signals, systems & computers

作者： Daisun Zhou Shu-Park Chan Circuits and Systems Research Laboratory Electrical Engineering and Computer Science Department Santa Clara University Santa Clara CA USA

An algorithm is presented to accomplish the global routing for general cell routing problems. More specifically, the branch-and-bound method is used to find the minimal cost path that is feasible between two pins on the routing surface. An extension of this algorithm is used to form multipoint nets. The algorithm is described and illustrated.

关键词： Routing Wire Pins Cost function Circuits and systems Laboratories Integrated circuit layout Search methods

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Electrokinetic pumping using traveling wave high voltages

Electrokinetic pumping using traveling wave high voltages

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Conference Record of the IEEE Industry Applications Society Annual Meeting (IAS)

作者： A.P. Washabaugh M. Zahn J.R. Melcher Department of Electrical Engineering and Computer Science Laboratory for Electromagnetic and Electronic Systems High Voltage Research Laboratory Massachusetts Institute of Technology Cambridge MA USA

Charge separation near a liquid/solid interface is explored by electrokinetic pumping of Freon TF and transformer oil using high-voltage traveling waves. Fluid-head-displacement measurements show strong dependencies on peak voltage amplitude (1.0-2.5 kV), frequency (0.1-20 Hz), and liquid conductivity (10/sup -13/-10/sup -9/ S/m). For any conductivity, reverse pumping (opposite to the traveling wave direction) occurs when the ratio of the voltage to the frequency is small, but switches to forward pumping when the ratio is large. The greatest displacement occurs when the dielectric relaxation and charge migration times are comparable. Preliminary measurements of average volume charge density, by sampling a portion of the liquid, relate net positive charge to forward pumping and net negative charge to reverse pumping. A charge transport analysis coupled to viscous dominated flow describes some features of the pumping.< >

关键词： Electrokinetics Voltage Pumps Solids Oil insulation Conductivity measurement Frequency measurement Switches Dielectrics Density measurement

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Sensitive low field Kerr electro-optic measurements in transformer oil

Sensitive low field Kerr electro-optic measurements in trans...

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Conference on electrical Insulation and Dielectric Phenomena, (CEIDP)

作者： D. Sheen T. Fujiwara M. Zahn Department of ELectrical Engineering and Computer Science Laboratory of Electromagnetic and Electronic Systems High Voltage Research Laboratory Massachusetts Institute of Technology Cambridge MA USA

A frequency-selective amplifier was used to make sensitive Kerr electro-optic field mapping measurements with a small signal AC voltage superimposed on a DC level. With several different electrode materials, including brass, stainless steel, and aluminium, the authors have observed very significant levels of field distortion due to positive space charge on the order of 400 mu C/m/sup 3/. It was possible to measure field strengths as low as 100 V/cm with typical average field strengths tested over the range of 500 V/cm to 29 kV/cm. The transient evolution of these fields was also measured, showing the transition from a uniform to a highly nonuniform field on a time scale on the order of 60 s.< >

关键词： Distortion measurement Signal mapping Frequency measurement Electrodes Building materials Steel Aluminum Space charge Testing Time measurement

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Transient charge conduction in high field stressed dielectrics

Transient charge conduction in high field stressed dielectri...

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International Symposium on electrical Insulation

作者： M. Zahn Department of Electrical Engineering and Computer Science Laboratory for Electromagnetic and Electronic Systems High Voltage Research Laboratory Massachusetts Institute of Technology Cambridge MA USA

Recent Kerr electrooptic field and charge mapping measurements in electron-beam-irradiated and high-voltage-stressed solid dielectrics are analyzed in terms of a drift-dominated conduction model. A one-dimensional model with a lossy dielectric medium is treated. Attention is directed to the transient decay after the excitation is removed and the terminals are either short- or open-circuited. The effects of relaxation are investigated.< >

关键词： Voltage Electrodes Differential equations Dielectric losses Solids Short circuit currents Current density Region 1

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Robust model parameter extraction using large-scale optimization concepts

Robust model parameter extraction using large-scale optimiza...

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Microwave, MTT-S International Symposium

作者： J.W. Bandler S.H. Chen S. Ye Q.J. Zhang Simulation Optimization Systems Research Laboratory Department of Electrical and Computer Engineering McMaster University Hamilton Canada Optimization Systems Associates Inc. Dundas ONT Canada

A robust approach to FET model parameter extraction is presented. By introducing DC constraints and formulating the modeling process as a complete and integrated optimization problem, the uniqueness and reliability of the extracted model parameters is improved. The approach uses multibias measurements and DC device characteristics in a sequential model building approach based on a decomposition dictionary that can be used to arrive at a suitable compromise between the simplicity and adequacy of the model. Novel automatic decomposition concepts for large-scale optimization are used to detect possible model topology deficiencies. A powerful l/sub 1/ optimization technique is used in the algorithm, and all the required gradients are provided through efficient adjoint analyses for both DC and AC sensitivities. A FET modeling example is described in detail to demonstrate the approach.< >

关键词： Robustness Parameter extraction Large-scale systems Power system modeling Equivalent circuits Microwave measurements Dictionaries Topology Scattering parameters Computational modeling

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An Integrated Approach to Controls and Diagnostics: The 4-Parameter Controller

An Integrated Approach to Controls and Diagnostics: The 4-Pa...

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American Control Conference (ACC)

作者： C. N. Nett C. A. Jacobson A. T. Miller Control Systems Laboratory GE Corporate Research and Development Center Schenectady NY USA Department of Electrical and Computer Engineering Northeastern University Boston MA USA

In this paper we present a theoretical basis for an integrated approach to the design of reliable control systems. In this approach, the control and diagnostic modules of a reliable control system are designed together, instead of independently, thereby accounting for the interactions which occur between these two modules in a functioning reliable control system. The approach makes use of a significant generalisation of the familiar 2-parameter controller known as the 4-parameter controller. This controller has two vector inputs and not one, but two vector outputs; correspondingly, this controller is comprised of not two, but four matrix parameters. The additional controller output is monitored to detect and isolate sensor and actuator faults, thereby providing the controller with diagnostic capabilities, or "intelligence," in addition to its control capabilities. Using a parameterization of all stabilising 4-parameter controllers, the fundamental limitations and inherent tradeoffs governing the design of reliable control systems are clarly delineated, with special attention given the issues of uncertainty and control/diagnostic interaction. Several means for resolving these desig tradeoffs are proposed, and illustrated by way of non-trivial examples. These results are expected to pave the way for the achievement of improved overall control/dignostic performance in reliable control systems, and also to pave the way for the achivement of significant complexity reductions in both the design and implementation of reliable control systems.

关键词： Control systems Fault detection Signal processing research and development Jacobian matrices Reliability theory Monitoring Actuators Uncertainty Intelligent control

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Yield Optimization of Large Scale Microwave Circuits

Yield Optimization of Large Scale Microwave Circuits

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European Conference on Microwave

作者： J.W. Bandler R.M. Biernacki S.H. Chen M.L. Renault J. Song Q.J. Zhang Optimization Systems Associates Inc. P.O. Box 8083 Dundas Ontario Canada L9H 5E7 Simulation Optimization Systems Research Laboratory Department of Electrical and Computer Engineering McMaster University Hamilton Canada L8S 4L7. Simulation Optimization Systems Research Laboratory Department of Electrical and Computer Engineering McMaster University Hamilton Canada Optimization Systems Associates Inc. Dundas ONT Canada

In this paper we demonstrate for the first time the feasibility of yield optimization of large scale microwave circuits. A combined strategy to attack this difficult problem is proposed, which includes the use of supercomputers, efficient approximation to the circuit responses, and the use of fast, dedicated simulation techniques. We have successfully accomplished the yield optimization of a 5 channel multiplexer with 75 design and toleranced variables, 124 constraints and up to 200 statistically perturbed circuits. No microwave circuit design of this type and on this scale has ever been reported.

关键词： Large-scale systems Microwave circuits Circuit optimization Design optimization Circuit synthesis Tunable circuits and devices Circuit simulation Supercomputers Constraint optimization Multiplexing

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A new class of sequential and adaptive algorithms with application to noise cancellation

A new class of sequential and adaptive algorithms with appli...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： M. Feder E. Weinstein A.V. Oppenheim Department of Electrical Engineering and Computer Science Research Laboratory of Electronics Massachusetts Institute of Technology Cambridge MA USA Department of Ocean Engineering Woods Hole Oceanographic Institution Woods Hole MA USA Department of Electronic Systems Faculty of Engineering Tel-Aviv University Tel-Aviv Israel

A class of sequential and adaptive algorithms for parameter estimation are presented that are based on the iterative estimate-maximize (EM) algorithm. In some cases sequential algorithms are derived that perform an exact EM step in each recursion; an example for these cases is given for the linear least-squares problem. In general, however, it is necessary to approximate the EM iteration in order to develop sequential algorithms. The application of this class of algorithms to the two-microphone noise cancellation problem is described.< >

关键词： Adaptive algorithm Noise cancellation Signal processing algorithms Iterative algorithms Parameter estimation Data engineering electrical capacitance tomography Current measurement Adaptive signal processing Resonance light scattering

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