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Computers, IEEE Transactions on

Issue 7 • Date Jul 1989

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Displaying Results 1 - 12 of 12
  • Performance of the direct binary n-cube network for multiprocessors

    Publication Year: 1989 , Page(s): 1000 - 1011
    Cited by:  Papers (62)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1000 KB)  

    A mathematical model for predicting the performance of the direct binary n-cube interconnection scheme is presented. These predictions are checked against simulations of a comparable system. The results for the network are compared to known results for indirect interconnection schemes like the crossbar and indirect n-cube networks. Special operation conditions such as broadcasts and hot spots are considered. The following main inferences can be drawn from the study. Indirect networks need to use switches of size significantly larger than 2×2 to equal or better the performance of the hypercube system, under equiprobable distribution of message destinations. Sources attached to nodes in the direct network must be capable of generating multiple messages in a cycle to exploit the available bandwidth fully which is a key difference from the indirect networks. A variant of the standard broadcast algorithm introduced achieves a balanced distribution of network traffic, permitting the hypercube to support significant amounts of broadcast messages. These studies indicate that the transient effects of potential hot spot nodes on the background messages are small in the case of the hypercube View full abstract»

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  • Improved techniques for estimating signal probabilities

    Publication Year: 1989 , Page(s): 1041 - 1045
    Cited by:  Papers (42)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB)  

    The problem is presented in the context of some recent theoretical advances on a related problem, called random satisfiability. These recent results indicate the theoretical limitations inherent in the problem of computing signal probabilities. Such limitations exist even if one uses Monte Carlo techniques for estimating signal probabilities. Theoretical results indicate that any practical method devised to compute signal probabilities would have to be evaluated purely on an empirical basis. An improved algorithm is offered for estimating the signal probabilities that takes into account the first-order effects of reconvergent input leads. It is demonstrated that this algorithm is linear in the product of the size of the network and the number of inputs. Empirical evidence is given indicating the improved performance obtained using this method over the straightforward probability computations. The results are very good, and the algorithm is very fast and easy to implement View full abstract»

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  • Models for the combined logical and physical design of databases

    Publication Year: 1989 , Page(s): 955 - 967
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1188 KB)  

    Given the set of intended transactions, the authors model the problem of choosing the most efficient decomposition of the universal set of attributes. Unlike other models which neglect the logical structure developed in database theory, the model developed incorporates it as part of a mathematical program. This provides a comprehensive and an integrated formulation for the combined logical and physical database design problem. The integrated problem and its ε-approximation schemes are shown to be NP-complete. An example shows the benefit of such an approach over more conventional ones View full abstract»

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  • On the fractal dimension of computer programs and its application to the prediction of the cache miss ratio

    Publication Year: 1989 , Page(s): 1012 - 1026
    Cited by:  Papers (24)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1024 KB)  

    Fractal geometry is proposed as a powerful measure of program behavior, and its application to the prediction of the miss ratio of programs in fully associative caches is presented. Programs are modeled as one-dimensional fractal random-walks. The fractal cache model is based on the parameterization of a program trace by a small number of constants, one of which is the fractal dimension of the program. The model is validated by trace-driven simulations of several program traces. With this model, it is possible to read the trace of a program once, and then predict the behavior of the miss ratio curve of that program in fully associative caches of varying sizes View full abstract»

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  • Representational and denotational semantics of digital systems

    Publication Year: 1989 , Page(s): 986 - 999
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1144 KB)  

    The input/output transformation effected by digital systems can be considered as concrete realizations of abstract mathematical functions. The mappings between abstract functions and concrete realizations, if kept explicit throughout the formulation, constitute the necessary `handles' (embodied by function definitions) for transformational reasoning about digital systems. Deductive reasoning can be factored out and reduced considerably. This is demonstrated by a functional recast of the major parts of digital systems theory. Since the emphasis of this study is on the method (transformational reasoning) rather than on new system concepts, examples are chosen from familiar areas. However, some new results are obtained View full abstract»

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  • Approximate analysis of single and multiple ring networks

    Publication Year: 1989 , Page(s): 1027 - 1040
    Cited by:  Papers (39)  |  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (912 KB)  

    Asynchronous packet-switched interconnection networks with decentralized control are very appropriate for multiprocessing and data-flow architectures. The authors present performance models of single- and multiple-ring networks based on token-ring, slotted-ring, and register-insertion-ring protocols. The multiple ring networks have the advantage of being reliable, expandable, and cost effective. An approximate and uniform analysis, based on the gate M/G/1 queuing model, has been developed to evaluate the performance of both existing single-ring networks and the proposed multiple-ring networks. Approximations are good for low and medium load. The analyses are based on symmetric ring structure with nonexhaustive service policy and infinite queue length at each station. They essentially involve modeling of queues with single- and multiple-walking servers. The results obtained from the analytical models are compared to those obtained from simulation View full abstract»

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  • Multidimensional balanced binary trees

    Publication Year: 1989 , Page(s): 968 - 985
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (988 KB)  

    A new balanced multidimensional tree structure called a k-dimensional balanced binary tree, where k is a positive integer, is presented and integrated. It is shown that the data structure can be used to manage a set of n k-dimensional data items such that access, insertion, and deletion operations can be supported in O(log n+k) time. The data structure is a multidimensional generalization of a balanced binary tree and retains much of the simplicity and efficiency of the base structure. The data structure requires O(k) single rotations for each insertion or deletion operation View full abstract»

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  • Fast rounding in multiprecision floating-slash arithmetic

    Publication Year: 1989 , Page(s): 1049 - 1052
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    A computational algorithm is described which quickly rounds large fractions into a fixed-length multiprecision floating-slash representation, using single-precision operations where possible. An easily calculated criterion for terminating the rounding process is given View full abstract»

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  • Efficient CSMA/CD-based protocols for multiple priority classes

    Publication Year: 1989 , Page(s): 943 - 954
    Cited by:  Papers (10)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (984 KB)  

    Efficient, reservation-based CSMA/CD protocols for handling multiple-priority-class traffic are presented. The new protocols allow the transmission of a varying-length stream of packets with just a single reservation. Two protocols are proposed, one for a system in which the number of active users (contenders) in the currently highest priority class can be determined during the reservation period, and the other for a system in which this number cannot be determined. If the number of active users is known, then optimal p-persistence is used to transmit the packets; otherwise, a dynamically determined combination of one-persistant and p-persistent periods is used to transmit the packets in the reserved priority group and to prevent lower priority users from interrupting the reserved priority transmission stream. Preemptive and nonpreemptive versions of the protocols are described. A simple analytical model is developed and used to obtain channel efficiency as a function of priority group size. Using this model, it is shown that the new protocols allow higher channel utilization than previous, reservation-per-attempted-transmission protocols View full abstract»

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  • A new algorithm for multiplication in finite fields

    Publication Year: 1989 , Page(s): 1045 - 1049
    Cited by:  Papers (14)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (420 KB)  

    A new algorithm is presented for computing the product of two elements in a finite field by means of sums and products in a fixed subfield. The algorithm is based on a normal basis representation of fields and assumes that the dimension m of the finite field over the subfield is a highly composite number. A very fast parallel implementation and a considerable reduction in the number of computations are allowed, in comparison to some methods discussed in the literature View full abstract»

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  • On fault-tolerant structure, distributed fault-diagnosis, reconfiguration, and recovery of the array processors

    Publication Year: 1989 , Page(s): 932 - 942
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (844 KB)  

    A study is made of the design of fault-tolerant array processors. It is shown how hardware redundancy can be used in the existing structures in order to make them capable of withstanding the failure of some of the array links and processors. Distributed fault-tolerance schemes are introduced for the diagnosis of the faulty elements, reconfiguration, and recovery of the array. Fault tolerance is maintained by the cooperation of processors in a decentralized form of control without the participation of any type of hardcore or fault-free central controller such as a host computer. Time redundancy is utilized by assigning the functions of the failed processors to fault-free processors View full abstract»

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  • Systolic s2-way merge sort is optimal

    Publication Year: 1989 , Page(s): 1052 - 1056
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    The time complexity of Thompson and Kung's (1977) s2 -way merge sort is analyzed and shown to be asymptotically optimal with respect to the recently improved lower bound on sorting on a mesh-connected n×n array. New lower bounds for systolic sorting are derived. A systolic version of s2 -way merge sort is systematically constructed and shown to be asymptotically optimal as well View full abstract»

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The IEEE Transactions on Computers is a monthly publication with a wide distribution to researchers, developers, technical managers, and educators in the computer field.

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Editor-in-Chief
Paolo Montuschi
Politecnico di Torino
Dipartimento di Automatica e Informatica
Corso Duca degli Abruzzi 24 
10129 Torino - Italy
e-mail: pmo@computer.org