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Classification of Gas-Liquid Two-Phase Flow Regime by an Ar-Model

IFAC Proceedings Volumes 1992年第15期25卷 597-602页

作者： K. Inoue G.N. Rao A. Mizutori Y. Morita K. Sekoguchi Department of Control Systems Engineering Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology Iizuka Fukuoka 820 Japan Department of Electronic Engineering Oita University Dannoharu Oita 870-11 Japan Department of Mechanical Engineering Osaka University Yamada-oka Suita Osaka 565 Japan

The discrimination of gas-liquid two-phase flow patterns has so far been made mainly by visual observation; and various flow parameters characterizing the flow, such as fluctuating pressures, void fraction etc., have been employed as quantitative tools for this purpose. It would be useful for the prediction and prevention of accidents experienced in thermal engineering plants dealing with the flow if it could be found the effective techniques for analyzing void fraction signals detected for diagnosing plant operation states. This paper presents pattern recognition and clustering techniques for analyzing the cross-sectional mean void fraction signals in gas-liquid two-phase flow based on an AR-model with bias components. The pattern recognition method based on the Bayes decision rule was applied for the recognition of flow regimes which were determined by visual observations. The clustering methods based on K-mean algorithm and mixture probability algorithm were applied for the determination of the new boundaries on a superficial gas-liquid velocities diagram. The effectiveness of the discussed techniques were confirmed.

关键词： pattern recognition clustering Bayes methods AR-model parameter estimation thermal plants multiphase flow void fraction

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An iteration scheme for dominant singular values

An iteration scheme for dominant singular values

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IEEE International Symposium on computer Aided control System Design (CACSD)

作者： J.R. Bar-on C.W. Gray Department of Electrical Engineering and Computer Science University of Oklahama Norman OK USA Control Systems Subdivision Aerospace Corporation El Segundo CA USA

An iteration method is presented for determining the largest singular value (2-norm) of a matrix, and its corresponding singular vectors. Connections with the power method and Bernoulli's method are presented. A formula is derived which describes the relationship between a matrix perturbation and the perturbation of its singular values.< >

关键词： Eigenvalues and eigenfunctions Symmetric matrices control systems Aerospace control Aerospace engineering Sparse matrices Iterative methods H infinity control Convergence Cellular neural networks

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Optimal Non-Parametric System Identification From Arbitrary Corrupt Finite Time Series: A control-Oriented Approach

Optimal Non-Parametric System Identification From Arbitrary ...

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American control Conference (ACC)

作者： Jie Chen Carl N. Nett Michael K. H. Fan Schools of Aerospace and Electrical Engineering Georgia Institute of Technology Atlanta GA USA Laboratory for Identification and Control of Complex Highly Uncertain Systems (LICCHUS) School of Aerospace Engineering Georgia Institute of Technology Atlanta GA USA Computer-Aided Control Systems Engineering Laboratory (CACSEL) School of Electrical Engineering Georgia Institute of Technology Atlanta GA USA

In this paper we formulate and solve a control-oriented system identification problem for single-input, single-output, linear, shift-invariant, distributed parameter plants. In this problem the available apriori information is minimal, consisting only of worst-case/deterministic, time dependent, upper and lower bounds on the plant impulse response and the additive output noise. The available aposteriori information consists of a corrupt finite output time series obtained in response to a known, non-zero but otherwise arbitrary, applied input. A novel system identification method is presented for this problem. This method maps the available apriori and aposteriori information into an "uncertain model" of the plant. The resulting uncertain plant model is comprised of a nominal plant model, a bounded additive output noise, and a bounded additive model uncertainty. The upper bound on the model uncertainty is explicit, worst-case/deterministic in nature, and expressed in terms of both the l 1 and H ∞ system norms. Under the assumption that the available apriori information is "correct" for the underlying physical plant, the resulting uncertain plant model has the property that it not only "explains" the available aposteriori information, but will also explain all aposteniori information observed in the future. Because this property hinges on the correctness of the available apriori information, a method is also presented for developing confidence that the available apriori information is in fact correct.

关键词： System identification Optimal control control systems Additive noise Robust control Uncertainty Noise level Aerospace engineering Upper bound Fasteners

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Joint detection/estimation for modal order selection in Gaussian and nonGaussian noise

Joint detection/estimation for modal order selection in Gaus...

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MILCOM, Military Communications Conference

作者： S.C.A. Thomopoulos T.W. Hilands Decision and Control Systems Laboratory Department of Electrical and Computer Engineering Pennsylvania State University University Park PA USA Applied Research Laboratory Pennsylvania State University University Park PA USA

The authors present a general approach to determining the number of sinusoids present in measurements corrupted by additive white Gaussian and nonGaussian noise. The approach involves the simultaneous application of maximum a posteriori detection and nonlinear estimation using either the extended Kalman filter when the noise is Gaussian, or the extended high order filter when the noise is nonGaussian. The problem is formulated as a multiple hypothesis testing problem with assumed known a priori probabilities for each hypothesis. The advantage of the approach lies in the potential to accommodate time-varying as well as time-invariant parameters in the measurement model. Experimental evaluation of the approach demonstrates excellent performance in selecting the correct model order and estimating the system parameters even for signal-to-noise ratios as low as -5 dB.< >

关键词： Gaussian noise State estimation Noise measurement Autocorrelation Matrix decomposition Recursive estimation control systems Additive noise Additive white noise Application software

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Nonlinear adaptive detection/estimation for single and multiple radar processing

Nonlinear adaptive detection/estimation for single and multi...

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MILCOM, Military Communications Conference

作者： S.C.A. Thomopoulos T.W. Hilands Department of Electrical and Computer Engineering Decision and Control Systems Laboratory Pennsylvania State University University Park PA USA Applied Research Laboratory Pennsylvania State University University Park PA USA

A nonlinear adaptive detector/estimator is introduced for single and multiple radar data processing. The problem of target detection from returns of monostatic radar(s) is formulated as a nonlinear joint detection/estimation problem on the unknown parameters in the signal return. The problems of detecting the target and estimating its parameters are considered jointly. A bank of spatially and temporally localized nonlinear filters is used to estimate the a posteriori likelihood of the existence of the target in a given space-time resolution cell. Within a given cell, the localized filters are used to produce refined spatial estimates of the target parameters. A decision logic is used to decide on the existence of a target within any given resolution cell based on the a posteriori estimates obtained from the likelihood functions. Simulation results show excellent detection capabilities and excellent resolution in target parameter estimation for both single and multiple sensor data.< >

关键词： Radar detection Spatial resolution Parameter estimation Detectors Data processing Object detection Nonlinear filters Signal resolution Refining Logic

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Nonlinear filtering methods for harmonic retrieval

Nonlinear filtering methods for harmonic retrieval

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MILCOM, Military Communications Conference

作者： T.W. Hilands S.C.A. Thomopoulos Applied Research Laboratory Pennsylvania State University University Park PA USA Decision and Control Systems Laboratory Department of Electrical and Computer Engineering Pennsylvania State University University Park PA USA

The authors address the problem of high-resolution parameter estimation of superimposed sinusoids using nonlinear filtering techniques. Six separate nonlinear filters are evaluated for the estimation of the parameters of sinusoids in white and colored Gaussian noise. Experimental evaluation demonstrates that the nonlinear filters perform very satisfactorily (close to the Cramer-Rao bound) for reasonable values of the initial estimation error. A major advantage of using nonlinear filtering methods for harmonic retrieval is that the filters can be applied to time-varying process models as well.< >

关键词： Filtering Power harmonic filters Nonlinear filters Noise measurement Parameter estimation Equations Gaussian noise Frequency estimation Damping White noise

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Sufficient Conditions for the Robust Stability of systems with Multiaffine Parameter Dependence

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IFAC Proceedings Volumes 1992年第21期25卷 168-171页

作者： B.D.O. Anderson F.J. Kraus M. Mansour S. Dasgupta Department of Systems Engineering Research School of Physical Sciences and Engineering Australian National University GPO Box 4 Canberra ACT 2601 Australia. Automatic Control Laboratory ETH Zurich 8092 Zürich Switzerland Department of Electrical & Computer Engineering University of Iowa Iowa City lA 52242 USA.

A number of robust stability problems take the following form: A polynomial has real coefficients wvhich are multiaffine in real parameters that are confined to a box in parameter space. An efficient method is required for checking the stability of this set of polynomials. We present two sufficient conditions in this paper. They involve: checking certain properties at the corners and edges of the parameter space box.

关键词： Robust Stability Multiaffine Parameter Dependence

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Supervisory control of mode-switch processes: Application to a flexible beam

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Annual Review in Automatic Programming 1992年 17卷 195-200页

作者： R.A. Hilhorst J. van Amerongen P. Löhnberg H.J.A.F. Tulleken Control Systems and Computer Engineering Group Department of Electrical Engineering University of Twente P.O. Box 217 7500 AE Enschede The Netherlands Mechatronics Research Centre Twente P.O. Box 217 7500 AE Enschede The Netherlands Department of Mathematics and Systems Engineering Operational Analysis and Optimization Group Koninklijkel Shell-Laboratorium (Shell Research B.V.) P.O. Box 3003 1003 AA Amsterdam The Netherlands

Many processes operate only around a limited number of operation points. In order to have adequate control around each operation point, an adaptive controller could be used. Then, if the operation point changes often, a large number of parameters would have to be adapted over and over again. This prohibits application of conventional adaptive control, which is more suited for processes with slowly changing parameters. Furthermore, continuous adaptation is not always needed or desired. An extension of adaptive control is presented, in which for each operation point the process behaviour can be stored in a memory, retrieved from it and evaluated. These functions are coordinated by a “supervisor”. This concept is referred to as supervisory control. It leads to an adaptive control structure which, after a learning phase, quickly adjusts the controller parameters based on retrieval of old information, without the need to fully releam each time. This approach has been tested on an experimental set-up of a flexible beam, but it is directly applicable to processes in e.g. the (petro)chemical industry as well.

关键词： Adaptive control Automatic tuning Learning systems Mode-switch processes Timevarying systems Supervisory control

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INTEGRATION OF SHIP control-systems FOR TOTAL SHIP SURVIVABILITY

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NAVAL ENGINEERS JOURNAL 1992年第4期104卷 114-116页

作者： SIMPSON, HL FAMME, JB TAYLOR, B Joseph Famme:is the manager of marine systems CAE-Link Silver Spring Maryland. Mr. Famme joined Link in 1983 where he is responsible for developing marine products including digital control and monitoring systems for ships and submarines. Prior to joining Link then Commander Famme served in the U.S. Navy in all shipboard assignments including command of an FF-1052 class frigate. His engineering duties included supervising new construction sea trials and major mid-life ship overhauls. Mr. Famme has written concept papers defining architectures for future platform control systems and has worked within the simulation industry to introduce the use of distributed computer-based systems for training. He is currently working with various naval organizations and shipbuilding companies to develop the next generation of integrated digital control systems for ships and submarines. Barry Taylor:is the manager of marine systems at CAE Electronics Montreal Canada. CAE is currently supplying the integrated control systems for four classes of ships: the Canadian Patrol Frigate the DDH-280 the USN MHC-51 Minehunter and the SA'AR 5 corvette under construction at Litton - Ingalls Shipbuilding. Prior to joining CAE Electronics in 1987 then Commander Taylor served in the Canadian Navy as an engineering duty officer. His tours included sea duty as the engineering officer on five ships and shore duty assignments including one in the Directorate responsible for ship machinery control systems in the Canadian Navy. Commander Taylor was also the program manager for the Shipboard Integrated Machinery Control System Advanced Development Model (SHINMACS ADM). He has had numerous papers published on integrated ship control systems.

Effective damage control in naval ships has always been an important element of the naval combat equation. After receipt of battle damage, the ship's offensive operational capability depends upon its ability to support or restore vital systems. This in turn depends on the degree of initial damage, the damage control readiness condition of the ship, and effectiveness of the crew in applying the ship's damage control doctrine. In addition to conventional shell, mine, and torpedo threats, the speed and lethality of modern weapon systems presents an increased requirement for damage control readiness. New technology for the monitoring and control of the ship's hull, mechanical, electrical, and damage control (HME&DC) systems is now available with the potential for improving damage control readiness and for aiding the ship's commander in executing his damage control doctrine. This paper will describe the evolution of ship control systems, and discuss the application of current ship control systems technologies to damage control. It will recommend an optimum approach to meeting the requirements of damage control readiness posed by modern day threats, working within the U.S. Navy concept called Total Ship Survivability (TSS).

关键词： Naval Vessels

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Visual pattern recognition using morphological methods

Visual pattern recognition using morphological methods

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

作者： I.N.M. Papadakis J.G. Reisman S.C.A. Thomopoulos Dept. of Electr. & Comput. Eng. Pennsylvania State Univ. University Park PA USA Decision and Control Systems Laboratory Department of Electrical and Computer Engineering Pennsylvania State University University Park PA USA

An effective method for visual pattern recognition using morphological techniques is presented. It is shown that it can be successfully used for the recognition of deformed letters. The method extracts morphological information by the successive dilation of an idealized letter set. At each stage a properly defined similarity index is computed. The maximum values of the similarity index for each stored letter are compared and are used for the classification decision. Classification results are presented for a set of deformed capital English letters with a realistic level of deformation. Skeletonization of the deformed pattern is shown to improve the performance of the classification method. The described method can be easily implemented using a parallel architecture.< >

关键词： Pattern recognition Artificial neural networks Feature extraction Clocks control systems Laboratories Data mining Parallel architectures Character recognition Tiles

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