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Harmonic insertion in PWM inverter drive schemes

European Transactions on Electrical Power 1992年第3期2卷 143-151页

作者： Theocharis, J. Petridis, V. Dr.-Ing. John Theocharis (1956) graduated as an Electrical Engineer from Aristotelian University of Thessaloniki.Greece in 1980. From 1980 to 1985 he has been with the scientific staff of the Department of Electrical Engineering at the Aristotelian University where he received the Ph.D. degree in 1985. Since 1986 he is working as a lecturer and in 1990 he became assistant professor at the Department of Electronics and Computer Engineering in the m e university. His research activities include control power electronics and electrical motor drives. Recently he is working with the Neural Network Systems with applications to field oriented control problems. Aristotelian University of Thessaloniki School of Engineering Faculty of Electrical Engineering Dept. of Electronics & Computer Engineering P.O. Box 438 GR-Thessalonikil/Greece.T+3131/219784Fax + 3031/274868) Prof. Dr.-Ing. Vasilis Petridis (1946) graduated from National Technical University of Athens Greece in 1969.He obtained the M.Sc. and the Ph.D. in electronics and systems from the University of London in 1970 and 1974. respectively. H i s interests include applied automatic control neural networks drives dynamic systems robotics etc. He is currently professor in the Department of Electronics and Computer Engineering of the University of Thessaloniki. (Aristotelian University of Thessaloniki. School of EngineeringFaculty of Electrical Engineering Dept. of Electronics & Computer Engineering P.O. Box 438. GR-ThessaloniW Greece T+3031/219784.Fax+3031/274868)

The procedure of harmonic insertion is generalized in this paper. Analytical expressions of the voltage spectra are derived. The insertion of the 3rd harmonic to the modulating signal, which is of particular interest, is considered as a special case. It is demonstrated in this case that the fundamental harmonic component of the phase and the line‐to‐line voltage is not affected by the insertion of the 3rd harmonic for sufficiently high values of the chopping ratio. However it has been shown that the higher harmonic spectrum is significantly improved as compared to the case of pure sinusoidal modulation. For different values of the fundamental component the optimal values of the amplitude of the third harmonic to be inserted have been calculated so that the distortion factor of the higher harmonic spectrum is minimized. Other cases of harmonic insertion are also considered which provide spectrum efficiency improvement. Experimental results are given which have been obtained by means of a microcomputer controlled PWM generator constructed for this purpose. Copyright © 1992 John Wiley & Sons, Ltd.

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IMPROVED CHANGE TRACKING FOR SOFTWARE MAINTENANCE

IMPROVED CHANGE TRACKING FOR SOFTWARE MAINTENANCE

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1991 CONF ON SOFTWARE MAINTENANCE

作者： GARLAND, JK CALLISS, FW Software Tools Development Honeywell Industrial Automation and Control Phoenix 85023 AZ United States Dept. of Computer Science and Engineering Arizona State University Tempe 85287-5406 AZ United States

ISBN: (纸本)081862325X

With an ever increasing body of software to maintain and a small number ofexperiencedpersonnel, it is critical to improve software maintenance practice. One difficult problem maintenance organizations must address is how to document program evolution. Problem or change reporting and tracking is a key aspect of recording changes to large software systems. Large software systems which evolve over a long period of time magnify the need for organized change tracking due to the number and extent of the changes made. This paper describes a method to incorporate problem solving information in a change tracking database. Problem solving is discussed with regard to structured problem solving techniques for isolating difficult problems. A relational database structure and queries to access the database are discussed. An example of how the change tracking system supports the maintenance problem solving process is also included. © 1991 IEEE.

关键词： computer software maintenance

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computer-aided control engineering Environments: Architecture, User Interface, Data-base Management, and Expert Aiding

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IFAC Proceedings Volumes 1990年第8期23卷 337-348页

作者： J.H. Taylor D.K. Frederick C.M. Rimvall H.A. Sutherland Control systems Laboratory GE Corporate Research and Development P.O. Box 8 Schenfctady NY 12301 USA Dept. of Electrical Computer andd Systems Engineering Rensselaer Polytechnic Institute Troy NY 12180 USA

Modern CAD environments for control systems engineering have begun to support substantial functionality beyond modeling, numerical analysis, and simulation. Three major areas that have emerged in the last five years are advanced user interfaces, data-base management, and expert-systems support ("expert aiding"), In addition, there has been a steady thrust to integrate more completely the various functionalities and software that comprise computer-aided control engineering (CACE). These trends have produced CACE environments which have relatively modest improvements in numerical quality but a vastly different "feel" in terms of integration, support, and "user friendliness. The basic considerations and requirements for a CACE user interface (UI), data-base manager (DBM), and expert aicling are discussed in detail. In many cases, these will be illustrated by examples based on various CACE software suites including the new GE MEAD CACE environment; the basic thrust will be to define needs and show how these can be met. The GE MEAD Project involves the integration of powerful CACE packages under a supervisor which coordinates the execution of these packages with a modern UI, a CACE-oriented DBM, and an expert system. The user interface is designed to facilitate access to the CACE package capabilities by users with widely different levels of familiarity with the environment. The data-base manager keeps track of system models that evolve over time and associates each analysis or design result with the correct model instance. The expert system supplies the machinery for expert aiding complicated or heuristic procedures to free the user from low-level detail and tedium. This system thus exemplifies the trends mentioned above

关键词： computer-aided system design computer interfaces for CAD control engineering applications of computers data-base management systems expert systems software tools

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Model of Rail Current on Electrification Railway

Model of Rail Current on Electrification Railway

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Tenth International Wrocław Symposium on Electromagnetic Compatibility

作者： Li Shaojun Wu Yunxi Computer Center Northern Jiaotong Univ. Beijing 100044 P.R. China Dept. of Comm. and Control Engineering Northern Jiaotong Univ. Beijing 100044 P.R. China

ISBN: (纸本)9798331500092

The traction network is a strong current, unbalanced. nonlinear, multi-conductor, time-varying distributed parameter system. The rails are under such a sophisticated electromagnetic field. The model of the rails current cannot be created very well only by conventional transmission line theory. Based on the Maxwell equation, the authors regard the model from the view of both field and circuit and then put forward the mathematical mode! The earth effect is considered. The model can be applied to not only homogeneous earth but also multi-layer earth. In addition, many factors are taken into consideration. For instance, the resistive, inductive and capacitive coupling, the earth potential and the frequency response of the traction system. Such parameters as the earth conductivity and the ballast resistance were tested on the railway side. Finally, the authors solved the model in digital computer and analyses the error. The test equipments of the strong current were developed successfully by our research group at the department of Comm. and control in Northern Jiaotong University. We used the test equipments to have made an experiment on the railway spot. The results of the theoretical analysis turn out to be sound.

关键词： Rails Earth Mathematical models Impedance Electric potential Rail transportation Couplings Conductivity Admittance Substations

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MAXIMUM-LIKELIHOOD SOFT DECODING OF BINARY BLOCK-CODES AND DECODERS FOR THE GOLAY CODES

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IEEE TRANSACTIONS ON INFORMATION THEORY 1989年第5期35卷 963-975页

作者： SNYDERS, J BEERY, Y Department of Electronic Communications Control and Computer Systems School of Engineering Tel-Aviv University Ramat-Aviv Israel Dept. of Electron. Commun. Control & Comput. Syst. Tel-Aviv Univ. Ramat-Aviv Israel

Maximum-likelihood soft-decision decoding of linear block codes is addressed. A binary multiple-check generalization of the Wagner rule is presented, and two methods for its implementation, one of which resembles the suboptimal Forney-Chase algorithms, are described. Besides efficient soft decoding of small codes, the generalized rule enables utilization of subspaces of a wide variety, thereby yielding maximum-likelihood decoders with substantially reduced computational complexity for some larger binary codes. More sophisticated choice and exploitation of the structure of both a subspace and the coset representatives are demonstrated for the (24, 12) Golay code, yielding a computational gain factor of about 2 with respect to previous methods. A ternary single-check version of the Wagner rule is applied for efficient soft decoding of the (12, 6) ternary Golay code.< >

关键词： Maximum likelihood decoding Block codes Lattices Computational complexity Binary codes Information theory Parity check codes Maximum likelihood detection Conferences Communication system control

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Automated layout synthesis in the YASC silicon compiler

Automated layout synthesis in the YASC silicon compiler

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23rd ACM/IEEE Design Automation Conference, DAC 1986

作者： Krekelberg, David E. Shragowitz, Eugene Sobelman, Gerald E. Lin, Li-Shin Advanced ECAD Laboratory Control Data Corporation MinneapolisMN55440 United States Dept. of Electrical Engineering University of Minnesota MinneapolisMN55455 United States Dept. of Computer Science University of Minnesota MinneapolisMN55455 United States

ISBN: (纸本)0818607025

In this paper, we present algorithms and experimental results for an automated layout synthesis procedure that is used in a high-level silicon compiler. The techniques consist of a unique approach to generalized cell synthesis, together with a novel solution of the placement and routing problem. Our algorithms take advantage of a larger space of possible solutions than is available in conventional, fixed-cell approaches to achieve compact and efficient layouts. First, our techniques for cell synthesis are presented. Then, we describe our placement algorithm, in which the locations of the cells are determined by signal-flow considerations. Next, our pin permutation procedure is described. These permutations are not limited to the relatively few cases of logically equivalent pins, but rather, can exploit a much larger set of transformations involving the re-arrangement of the inner structure of the cells themselves. Finally, our techniques for both global and channel routing are discussed. Experimental results for a complete chip layout are included. © 1986 IEEE.

关键词： Silicon

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Automated layout synthesis in the YASC silicon compiler 86

Automated layout synthesis in the YASC silicon compiler

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Proceedings of the 23rd ACM/IEEE Design Automation Conference

作者： David E. Krekelberg Eugene Shragowitz Gerald E. Sobelman Li-Shin Lin Advanced ECAD Laboratory Control Data Corporation Minneapolis MN Dept. of Electrical Engineering University of Minnesota Minneapolis MN Dept. of Computer Science University of Minnesota Minneapolis MN

ISBN: (纸本)9780818607028

In this paper, we present algorithms and experimental results for an automated layout synthesis procedure that is used in a high-level silicon compiler. The techniques consist of a unique approach to generalized cell synthesis, together with a novel solution of the placement and routing problem. Our algorithms take advantage of a larger space of possible solutions than is available in conventional, fixed-cell approaches to achieve compact and efficient ***, our techniques for cell synthesis are presented. Then, we describe our placement algorithm, in which the locations of the cells are determined by signal-flow considerations. Next, our pin permutation procedure is described. These permutations are not limited to the relatively few cases of logically equivalent pins, but rather, can exploit a much larger set of transformations involving the re-arrangement of the inner structure of the cells themselves. Finally, our techniques for both global and channel routing are discussed. Experimental results for a complete chip layout are included.

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Yet another silicon compiler 85

Yet another silicon compiler

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Proceedings of the 22nd ACM/IEEE Design Automation Conference

作者： David E. Krekelberg Gerald E. Sobelman Chu S. Jhon Advanced ECAD Department Control Data Corporation Minneapolis MN Dept. of Electrical and Computer Engineering University of Iowa Iowa City IA

ISBN: (纸本)9780818606359

In this paper, we describe the YASC high-level silicon compiler which synthesizes compact chip layouts from hierarchical behavioral descriptions. A logic synthesis procedure generates sets of Boolean equations, including multi-phase clocks and any necessary interface logic. A novel technique for layout generation yields cells whose densities approach hand-crafted designs. Two-layer metal NMOS and CMOS technologies are supported, with flexible design rules. In addition to layout synthesis, logic, schematic and graph diagrams are generated directly from a powerful internal data base. The compiler, which runs under the UNIX^^ operating system, includes a menu-driven multi-windowing user environment.

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A Proposed Information System to Master the Maintenance Program in an Iron & Steel Complex

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IFAC Proceedings Volumes 1977年第11期10卷 259-265页

作者： S.A.K. El Sheshe A.G. Hamdy S.E. Aidarous Metallurgical Dept. The General Organization for Industrialization Head of Instrumentation & Control Dept. The Egyptian Iron & Steel Co. Computer & Control Section Faculty of Engineering Ain Shams University Cairo

There is a variety of units existing in the Egyptian Iron & Steel Complex In Helwan area that has been installed in several steps, during a period of two decades. Different suppliers and companies took part in the delivery, erection, and putting into operation of production and auxiliary components of the plant. This situation created difficulties in maintenance, spare parts availability, also some problems in the programming for preventive maintenance duties. In this paper, an information system was developed and adapted to suit the local conditions with the aim to control maintenance viork spare parts production in the local workshops, and to have an inventory control over spares and consumption materials. Such a system was developed taking into consideration the relations between dependent shops, loading of adjacent shops, besides, looking after safe stock level of spares without overloading the economy of the plant. The success of such a system depends upon data collection, continuous information flow from different prcduction shops, and is mainly dependent on people monitoring the system and the efficient computer centerin the plant.

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Sectorial analysis for the metallurgical industries in the Arab world

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IFAC Proceedings Volumes 1977年第14期10卷 113-118页

作者： Sayed Abdel Kader Salah El Din Aidarous El Sayed Metwally The General Organization for Industrialization Metallurgical Dept. Computer and Control Section Fac. of Engineering Ain Sham University Industrial Development Centre for Arab States

A general review of the Industrial planning sector in the Arab World is presented. A sectorial analysis is given showing the interaction between the different concerned Governmental Organization together with their impact on the planning process. The role of the public and private sectors has been discussed with special emphasis on the hletallurgical Industries as an example. The interaction between national and regional planning organizations is considered.

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