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IEEE Symposium on computers and Communications (ISCC)

作者： M. Kholief I. Awad M. El-Derini M. Nagi H. Ali Department of Computer Science Old Dominion University Norfolk VA USA Department of Computer Science and Automatic Control Faculty of Engineering Alexandria University Alexandria Egypt

Static task scheduling in distributed computing systems is a very complex problem and known to be NP-hard. This problem is even harder when the module execution times become probabilistic. In this paper we study the effect of probabilistic module execution times on the performance of task-scheduling algorithms. We show that in static task scheduling, for probabilistic module execution times, and in the existence of some factors there is no need to use an expensive task-scheduling algorithm. Given any two static task-scheduling algorithms that use deterministic module execution times in assigning task modules to the distributed system, the performance of these two algorithms will not remain the same when these module execution times become probabilistic rather than deterministic. We also study the effects of some factors an our results.

关键词： Scheduling algorithm Processor scheduling computer science automatic control Read only memory Distributed computing Heuristic algorithms State-space methods

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The ALEX Object Manager

The ALEX Object Manager

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IEEE Symposium on computers and Communications (ISCC)

作者： A.A. Saad G. Badr Computer Science and Automatic Control Department Faculty of Engineering Alexandria University Alexandria Egypt

Object-oriented database systems aim at meeting the data modelling, performance, cooperative design and version management requirements of current advanced applications, such as CAD (computer-aided design), CAM (computer-aided manufacturing), CASE (computer-aided software engineering), CIM (computer integrated manufacturing), hypermedia and expert systems. This paper presents the ALEX Object Manager, which is a part of the ALEX object-oriented database management system that is being developed based on the ODMG-93 standard. The system decomposition and process layout are presented, some implementation problems are discussed and the current status of the system is reported.

关键词： Database systems Design automation computer aided manufacturing computer aided software engineering computer integrated manufacturing Object oriented modeling engineering management Application software CADCAM Expert systems

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A Robust Non-Linear control Design for a Turbogenerator

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IFAC Proceedings Volumes 1997年第21期30卷 275-280页

作者： V. Vesely J. Simovec D.P. Papadopoulos Department of Automatic Control Systems Faculty of Electrical Engineering and Information Technology Slovak University of Technology Bratislava. Department of Electrical Computer Engineering Democritos University of Thrace 67100 Xanthi Greece

In this paper is presented a new approach to robust non-linear control design, which can guarantee a prescribed decay rate of exponential stability for known system uncertainties. The proposed approach doesn’t employ matching conditions. The non-linear power system with deterministic uncertainties is chosen as demonstration example.

关键词： robust non-linear exponential stability semi-linear power system

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A Method of Robust Fault Detection for Dynamic Systems by Using Quasi-ARMAX Modeling

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IFAC Proceedings Volumes 1997年第11期30卷 1157-1162页

作者： K. Kumamaru J. Hu K. Inoue T. Söderström Department of Control Engineering and Science Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology Iizuka 820 Fukuoka Japan Department of Automatic Control and Systems Analysis Institute of Technology Uppsala University P.O.Box 27 Uppsala Sweden

This paper presents a model-based approach to fault detection of dynamic systems, which is robust to unmodeled dynamics. A “Quasi-ARMAX model᾿ is first proposed for describing nonlinear systems by incorporating a group of certain nonlinear structures into a linear ARMAX structure. The model can be used for a best linear approximation of the system, as well as for the estimation of resulting unmodeled dynamics, by a hierarchical implementation of recursive identification. Then robust fault detection is performed based on thresholding approach using Kullback discrimination information as fault detection index, in which the estimated unmodeled dynamics is incorporated.

关键词： Dynamic systems fault detection Kullback discrimination information modeling errors nonlinear systems robust performance

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Fault Detection of Nonlinear Systems by Using Hybrid Quasi-ARMAX Models

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IFAC Proceedings Volumes 1997年第18期30卷 1125-1130页

作者： K. Kumamaru J. Hu K. Inoue T. Söderström Department of Control Engineering and Science Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology Iizuka 820 Fukuoka Japan. Department of Automatic Control and Systems Analysis Institute of Technology Uppsala University P.O.Box 27 Uppsala Sweden

This research is concerned with fault detection of nonlinear systems using Kullback discrimination information (KDI) as an index. A hybrid quasi-ARMAX model is proposed, which combines a linear ARMAX model and a multi-ARX-model based on interpolation. In the case where the faults occur on the ARMAX model part, a KDI-based "robust" fault detection is performed, in which multi-ARX-model part is treated as error due to nonlinear undermodeling. In other cases, the model is transformed into several local ARMAX models and fault detection is performed by using the KDI to discriminate each identified local model. In this paper, we mainly concentrate our discussion on the latter cases.

关键词： Nonlinear systems dynamic systems fault detection Kullback discrimination information quasi-ARMAX modeling local model

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On the numerical speed control of electrical drive systems using stepping motors

On the numerical speed control of electrical drive systems u...

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IEEE International Conference on Intelligent engineering Systems (INES)

作者： G. Baluta S. Resmerita Faculty of Electrical Engineering Department of Electric Drivcs and Power Electronics E2809CGh. Asachi E2809DTechnical University of Iasi Lasi Romania Faculty of Automatic Control and Computer Engineering Department of Automatic Control and Industrial Informatics E2809CGh. Asachi E2809DTechnical University of Iasi Lasi Romania

The paper focuses on the speed control of stepping motors in a closed-loop configuration. An incremental optical encoder is used as the position transducer, allowing the achievement of a minor loop. The numerical control algorithm is implemented using an IBM PC together with a specialized interface for stepper motors. The solution was obtained in two steps: the first was a nonlinear control law and the second was the improvement of the first one by using a PI part.

关键词： Velocity control Samarium automatic control Pulse circuits Optical feedback Nonlinear optics Transducers computer numerical control Digital control Pulse generation

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Considerations Concerning the Speed control of Electrical Drive Systems with Stepper Motors

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IFAC Proceedings Volumes 1997年第27期30卷 455-460页

作者： Gheorghe Bãluṭă Ştefan Resmeriṭă Gheorghe Bäluṭă “Gh. Asachi” Technical University of Iasi Faculty of Electrical Engineering Electric Drives and Power Electronics Department Str. Horia No. 7-9 6600 Iasi Romania tel.032/112770 Ştefan Resmeriṭà “Gh. Asachi” Technical University of Iasi Faculty of Automatic Control and Computer Engineering Department of Automatic Control and Industrial Informatics Str. Horia No. 7-9 6600 Iasi Romania tel. 032/116502 tuiasi.ro

This paper presents a method for Stepper Motor (SM) speed control by means of a minor loop. The compatibility of the SM with the digital electronics allowed a PC to be used for implementing the control algorithm, the SM control being achieved by two hardware interface levels. The SM command is realized with two specialized circuits: L297 (SM controller) and L298N (driver). The control signals for this level are generated through a parallel port 18255 and a programmable timer 18253. Some other circuits complete the microprocessor interface. The software has the following tasks: speed measurement and control algorithm achievement of a PI type. To tune this controller the system characteristics are measured, when the system is unstable, having a relay instead of the PI part. There are treated aspects on choosing the sample period, the position transducer, and the type of speed measurement.

关键词： control applications control closed-loop Stepping motors Numerical algorithms computer controlled systems

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Analysis of deadlocks and circular waits using a matrix model for discrete event systems

Analysis of deadlocks and circular waits using a matrix mode...

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IEEE Conference on Decision and control

作者： F.L. Lewis S. Bogdan A. Gurel O. Pastravanu Automation and Robotics Research Institute University of Texas Arlington Worth TX USA Faculty of Electrical Engineering and Computer University of Zagreb Zagreb Croatia Department Automatic Control and Ind. Inf Polytechnic Institute Iasi Romania

A new matrix rule-based model of discrete-part discrete event systems is given that, together with the well-known Petri net marking transition equation, yields a complete matrix-based dynamical description of these systems. In this application to deadlock analysis, the exact relations between circular blockings and deadlocks are given for a large class of reentrant flow lines. Explicit matrix equations are given for online dynamic deadlock analysis in terms of circular blockings, and certain 'critical siphons' and 'critical subsystems'. This allows efficient dispatching with deadlock avoidance using a generalized kanban scheme. For the class of flow lines considered, the existence of matrix formulae shows that deadlock analysis is not NP-complete, but of polynomial complexity.

关键词： System recovery Discrete event systems Equations Dispatching Robotics and automation Petri nets Manufacturing Bills of materials Assembly Lifting equipment

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Intelligent controller design for the ship steering problem

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IEE PROCEEDINGS-control THEORY AND APPLICATIONS 1996年第1期143卷 17-24页

作者： Enab, YM Faculty of Engineering Automatic Control & Computer Engineering Department El-Mansoura University El-Mansoura Egypt

The reason for the present upsurge of interest in intelligent control is that the present generation of control systems are incapable, to a greater or lesser extent, of dealing with problems of a certain complexity. Fortunately, the human operator (HO) is often expert in keeping the complex control systems on the right track. In this paper a method for controller design has been investigated based on a concept of developing a mathematical model for HO behaviour. The method treats HO behaviour as a dynamic process by itself, transformed from the unknown dynamics of the ship to be controlled. The method of controller design entails observing the human controller, constructing a model of the human controller, and using that model as a basis for an automatic control system. During the observation phase the HO controls the ship and the data representing the state of the ship and human actions are registered. During the modelling phase, a human operator behaviour model (HOBM) is constructed as a neural network and its parameters are estimated. During the testing phase, the HOBM controls the ship and its performance is evaluated under the observation phase conditions and completely different conditions. The method has been successfully applied using computer simulation for the ship steering problem.

关键词： man-machine systems intelligent control neural networks learning systems

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Robust Fault Detection Using Index of Kullback Discrimination Information

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IFAC Proceedings Volumes 1996年第1期29卷 6524-6529页

作者： K. Kumamaru J. Hu K. Inoue T. Söderström Department of Control Engineering and Science Faculty of Computer Science and Systems Engineering Kyushu Institute of Technology Iizuka 820 Fukuoka Japan. Department of Automatic Control and Systems Analysis Institute of Technology Uppsala University P.O.Box 27 Uppsala Sweden

This paper presents a robust fault detection system (FDS) for dynamic systems with unmodeled dynamics. In the FDS, umnodeled dynamics is first qualified as soft bound, which as well as model parameters are estimated using a robust identification algorithm. Then as a fault detection index, Kullback discrimination information (KDI) is derived into a feasible form and an index of umnodeled dynamics is also introduced. A decision making scheme is thus developed so that fault detection is carried out based on the KDI, the index of umnodeled dynamics and other prior information about the system.

关键词： Fault detection parameter identification stochastic modeling robust estimation uncertainty

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