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Computers and Digital Techniques, IEE Proceedings E

Issue 6 • Date November 1985

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Displaying Results 1 - 6 of 6
  • New trapdoor-knapsack public-key cryptosystem

    Page(s): 289 - 292
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (414 KB)  

    The paper presents a new trapdoor-knapsack public-key cryptosystem. The encryption equation is based on the general modular knapsack equation, but, unlike the Merkle-Hellman scheme, the knapsack components do not have to have a superincreasing structure. The trapdoor is based on transformations between the modular and radix form of the knapsack components, via the Chinese remainder theorem. The security is based on factoring a number composed of 256 bit prime factors. The resulting cryptosystem has high density, approximately 30% message expansion and a public key of 14 Kbits. This compares very favourably with the Merkle-Hellman scheme which has over 100% expansion and a public key of 80 Kbits. The major advantage of the scheme when compared with the RSA scheme is one of speed. Typically, knapsack schemes such as the one proposed here are capable of throughput speeds which are orders of magnitude faster than the RSA scheme. View full abstract»

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  • Real-time on-line pattern recognition of eye position and movement

    Page(s): 293 - 308
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1707 KB)  

    A pattern recognition technique has been successfully used as a noninvasive, accurate and sensitive method for direct on-line and real-time measurement of instantaneous eyeball positions and movements. The scheme uses a vidicon camera as the input to a microcomputer system. Both hardware and software windowing are used for tracking eye positions adaptively. The system can be applied to study both one- and two- dimensional eye movements. An error analysis of the approach is also included. View full abstract»

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  • Feature determination and inexact matching of images of industrial components

    Page(s): 309 - 315
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1494 KB)  

    Techniques for the segmentation and recognition of images of overlapping industrial components in visually cluttered environments are described. Image segmentation is based on the Hough transformation of preprocessed edge data, employed as a predictive mechanism for line fitting, merging and redundancy checking, coupled with feedback verification. In the recognition phase, the extracted features are matched inexactly against a database of known models. Hypotheses are based on local feature matches and verified, first, by comparison of a translated and rotated prototype with the feature data, and, secondly, by re-examination of the original gradient data. Examples of experiments performed on single and multiple-component images are presented, demonstrating the robustness of the method. View full abstract»

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  • Markov models for a multiple processor system with a shared bus

    Page(s): 316 - 322
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (858 KB)  

    A finite population queueing model applicable to a class of real-time multiple processor systems with a shared bus is developed and analysed. It assumes Poisson arrivals and services, and its service discipline is FIFO, with the restriction that a customer cannot be served for the (k + l)st time unless all customers have been served k times. The performance of the system is studied by evaluating its throughput. In the special case of equal arrival and service rates, the model reduces to a simpler one, whose solution is obtained by a recursive technique that reduces significantly the computation time. Under certain conditions, the simplified model provides a good approximation to the throughput predicted by the general model. View full abstract»

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  • Virtual memory for microcomputers

    Page(s): 323 - 332
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1370 KB)  

    The use and design of segmented virtual memories suitable for microcomputers is considered from the user interface through the system software to the hardware interface. The provision of a UNIX*-like interface within a segemented virtual machine is outlined. Performance measurements are presented of a paged, segmented system running real workloads. View full abstract»

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  • Completely decentralised communication control in microcomputer clusters

    Page(s): 333 - 338
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (710 KB)  

    Very closely located single-board or single-chip microcomputers, co-operating for a common task, can be linked as clusters, with their sizes being changed arbitrarily depending on the task parallelism and the resources available from each node (microcomputer). Intracluster communications are handled by identical bus/memory arbiters, one in each node. The arbiters switch microprocessors and memories in the same or different nodes to different sides of communication paths. Node-to-node data transfer is fully interlocked, and the performance of each cluster can be predicted with very good accuracy when the number of co-operating nodes and the fractional external memory accesses are known. View full abstract»

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