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Computers and Digital Techniques, IEE Proceedings E

Issue 4 • Date July 1986

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Displaying Results 1 - 6 of 6
  • Novel data packing algorithm for improved string matching

    Page(s): 185 - 193
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1194 KB)  

    A novel method for packing sequential data offers improvements in the efficiency of pattern-matching algorithms. The technique utilises the stochastic synchronisation capability of the augmented T-codes, and the typographical packing procedure provided by the binary-depletion T-codes. The two homomorphic coding systems used here and previously presented are introduced briefly again in an informal development of the packing scheme. In the proposed scheme the problem of locating a pattern within a packed data sequence is seen to be analogous to that of determining synchronisation during the decoding of a corrupted message sequence. The systematic details for implementation of the scheme are discussed in terms of a practical application using sequences of naturally occurring DNA code. View full abstract»

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  • Use of multiplexers in direct synthesis of ASM-based designs

    Page(s): 194 - 200
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (882 KB)  

    Techniques are described for translating an ASM chart or table directly into a variety of synthesis forms. These include PROM-, FPLA- and multiplexer-based implementations. A method for improving the circuit economy based on the preselection of qualifiers by means of multiplexers is presented. An algorithm for the simplification of multiplexer networks is also included. View full abstract»

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  • Flexible communication structure for distributed embedded systems

    Page(s): 201 - 211
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1735 KB)  

    The paper describes an extensible communication system for Conic, an architecture for distributed embedded systems. Conic provides a high level programming language with interprocess communication primitives suited to both local and remote communication. These primitives are sufficiently powerful to be used for applications programming yet simple and efficient enough for programming system software. The communication system which supports these primitives is itself implemented in the Conic language. It provides a very simple datagram-like service, over interconnected local area networks. The configuration flexibility of Conic is exploited to allow extension of the basic communication system to give additional services such as virtual circuit or routing. The paper also relates the Conic communication system to the ISO Reference Model and indicates some of the problems of using the model. An earlier version of this paper was presented at the 5th IFAC Workshop on Distributed Computer Control Systems, Sabi Sabi, South Africa, May 1983. View full abstract»

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  • Pedagogic computers

    Page(s): 212 - 222
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1563 KB)  

    Laboratory experiments to familiarise students with the principles of digital control structures, such as computer processors, have in the past been difficult to implement because of the quantity and complexity of the equipment needed. Many institutions have constructed small computers from MSI components, requiring 20¿¿30 hours of a student's time, and providing little, if any, scope for experimentation. A modular approach to the data part of a digital system may be provided with modern LSI components. If a similarly modular approach is taken to the design of the control part, it is possible for an elementary computer to be assembled in as little as two or three hours. Experimentation with a variety of computer processor designs and methodologies for the implementation of the control structure is then possible within the bounds of a short laboratory course, and first hand experience of design tradeoffs can be obtained. The paper describes equipment suitable for such teaching and discusses the design of several simple computer processors intended to provide experience of the use of digital control techniques in instruction format decoding, addressing mode implementation etc. View full abstract»

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  • Microcomputer system specification using interval logic and a modified labelled-net model

    Page(s): 223 - 234
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1370 KB)  

    The application of interval logic and modified labelled-net models for system specification and verification is introduced. By means of interval logic and modified labelled-net models, system properties involving time interval information can be specified and verified. In interval logic, derivation rules are used to obtain the criteria on the time relationships for the correct implementation of the system. The verification of system properties by derivation rules can be performed in the net space by net transformations which can be handled by an interactive computer. The human decision to select an appropriate net transformation rule is indispensable. Token passing is used to verify that the criteria for correct implementation are met by the parameters of a given set of components. An offline program without human intervention may be used to perform this job. An application example of a microcomputer system is used to demonstrate the power of these models. View full abstract»

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  • Efficient parallel processing technique for inverting matrices with random sparsity

    Page(s): 235 - 240
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (747 KB)  

    Algorithms for ordering a sparse matrix A for parallel triangular factorisation and for obtaining the parallel inverse of A are given. The heuristic ordering method is based on graph manipulations. It attempts to minimise the completion time of parallel triangular factorisation while preserving the sparsity of the matrix. The inversion method proposed is based on the triangular factors of A. The task of obtaining the `sparse inverse¿¿of A is represented by a directed acyclic graph. The algorithm and the graph for the full inversion of A are also given. Claims are substantiated by experiments using test data from several electric networks. View full abstract»

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