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IEEE Transactions on Information Theory

Issue 5 • Date Sep 1997

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Displaying Results 1 - 25 of 46
  • Cryptographically resilient functions

    Publication Year: 1997, Page(s):1740 - 1747
    Cited by:  Papers (31)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    This correspondence studies resilient functions which have applications in fault-tolerant distributed computing, quantum cryptographic key distribution, and random sequence generation for stream ciphers. We present a number of new methods for synthesizing resilient functions. An interesting aspect of these methods is that they are applicable both to linear and nonlinear resilient functions. Our se... View full abstract»

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  • On the spectrum of distances of a multilevel code, decoded by a multistage decoder

    Publication Year: 1997, Page(s):1736 - 1740
    Cited by:  Papers (5)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    In this correspondence we are concerned with the error rates contributed by component codes in a multilevel code, decoded by a multistage decoder. These error rates are required for estimating the performance of the structure, but more importantly, they can serve as a design tool for achieving high coding gain. The latter objective can be reached by approaching a balance among these error rates. F... View full abstract»

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  • Collision-type multiple-user communications

    Publication Year: 1997, Page(s):1725 - 1736
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (452 KB)

    A collision-type multiple access system is investigated in which every user transmits symbols from a common N-ary frequency-shift-keyed signal alphabet. We present a series of information-theoretic properties of the associated mathematical channel model. In the absence of noise, we calculate a large system approximation to the sum capacity, which is used to show that, in the limit, the combining o... View full abstract»

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  • New constant weight codes from linear permutation groups

    Publication Year: 1997, Page(s):1623 - 1630
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    New constant weight codes are found by considering certain linear permutation groups. A code is obtained as a collection of orbits of words under such a group. This leads to a difficult optimization problem, where a stochastic search heuristic, tabu search, is used to find good solutions in a feasible amount of time. Nearly 40 new codes of length at most 28 are presented View full abstract»

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  • Covering numbers for real-valued function classes

    Publication Year: 1997, Page(s):1721 - 1724
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    We find tight upper and lower bounds on the growth rate for the covering numbers of functions of bounded variation in the L1 metric in terms of all the relevant constants. We also find upper and lower bounds on covering numbers for general function classes over the family of L1(dP) metrics in terms of a scale-sensitive combinatorial dimension of the function class View full abstract»

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  • New single asymmetric error-correcting codes

    Publication Year: 1997, Page(s):1619 - 1623
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (240 KB)

    New single asymmetric error-correcting codes are proposed. These codes are better than existing codes when the code length n is greater than 10, except for n=12 and n=15. In many cases one can construct a code C containing at least [2n/n] codewords. It is known that a code with |C|⩾[2n/(n+1)] can be easily obtained. It should be noted that the proposed codes for n=12 and ... View full abstract»

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  • Nonuniform sampling of bandlimited signals with polynomial growth on the real axis

    Publication Year: 1997, Page(s):1717 - 1721
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    We derive a sampling expansion for bandlimited signals with polynomial growth on the real axis. The sampling expansion uses nonuniformly spaced sampling points. But unlike other known sampling expansions for such signals, ours converge uniformly to the signal on any compact set. An estimate of the truncation error of such a series is also obtained View full abstract»

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  • Long packing and covering codes

    Publication Year: 1997, Page(s):1617 - 1619
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (180 KB)

    We study geometrically the domain of linear binary codes and of unrestricted binary codes in the plane (normalized covering radius, normalized minimal distance) View full abstract»

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  • Stochastic iterative algorithms for signal set design for Gaussian channels and optimality of the L2 signal set

    Publication Year: 1997, Page(s):1574 - 1587
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (764 KB)

    We propose a stochastic iteration approach to signal set design. Four practical stochastic iterative algorithms are proposed with respect to equal and average energy constraints and sequential and batch modes. By simulation, a new optimal signal set, the L2 signal set (consisting of a regular simplex set of three signals and some zero signals), is found under the strong simplex conjecture (SSC) co... View full abstract»

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  • On generalized stable nonuniform sampling expansions involving derivatives

    Publication Year: 1997, Page(s):1714 - 1716
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (144 KB)

    We establish a general sampling expansion involving derivatives for the Paley-Wiener class of functions. It can be thought of as a generalization of Rawn's (1989) result since it is based on the arbitrary sequence of desired derivative order. Also, the class of corresponding nonuniform sampling sequences is more general, i.e., more irregular than those usually encountered in literature View full abstract»

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  • Characterization of quaternary extremal codes of lengths 18 and 20

    Publication Year: 1997, Page(s):1613 - 1616
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (188 KB)

    We prove that, up to equivalence, there is a unique extremal quaternary Hermitian self-dual code of length 18, and that there are two inequivalent extremal quaternary Hermitian self-dual codes of length 20 View full abstract»

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  • Gauss-Markov random fields (CMrf) with continuous indices

    Publication Year: 1997, Page(s):1560 - 1573
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (676 KB)

    Gauss-Markov random fields (GMrfs) play an important role in the modeling of physical phenomena. The paper addresses the second-order characterization and the sample path description of GMrf's when the indexing parameters take values in bounded subsets of ℜd, d⩾1. Using results of Pitt (1994), we give conditions for the covariance of a GMrf to be the Green's function of a partia... View full abstract»

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  • A suboptimal lossy data compression based on approximate pattern matching

    Publication Year: 1997, Page(s):1439 - 1451
    Cited by:  Papers (49)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (704 KB)

    A practical suboptimal (variable source coding) algorithm for lossy data compression is presented. This scheme is based on approximate string matching, and it naturally extends the lossless Lempel-Ziv (1977) data compression scheme. Among others we consider the typical length of an approximately repeated pattern within the first n positions of a stationary mixing sequence where D percent of mismat... View full abstract»

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  • How many information bits does a decoder need about the channel statistics?

    Publication Year: 1997, Page(s):1707 - 1714
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB)

    We investigate the minimum amount of side information about the channel statistics that must be provided to the decoder in order to guarantee reliable communication in the random coding sense, for certain classes of channels View full abstract»

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  • Improvements to the bounds on optimal ternary linear codes of dimension 6

    Publication Year: 1997, Page(s):1632 - 1638
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB)

    New ternary codes of dimension 6 are presented which improve the bounds on optimal linear codes. These codes belong to the class of quasi-twisted (QT) codes, and have been constructed using a greedy algorithm. This work extends previous results on QT codes of dimension 6. In particular, several new two-weight QT codes are presented. Numerous new optimal codes which meet the Griesmer bound are give... View full abstract»

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  • On the aperiodic and odd correlations of the binary Shanbhag-Kumar-Helleseth sequences

    Publication Year: 1997, Page(s):1593 - 1596
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    A previously derived upper bound on hybrid sums over Galois rings is combined with a method due to Vinogradov (1954) to obtain an upper bound for the maximum aperiodic and odd correlations of the binary sequences constructed by Shanbhag, Kumar, and Helleseth (see Proc. 1995 IEEE Int. Symp. on Information Theory, 1995) View full abstract»

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  • Fixed-slope universal lossy data compression

    Publication Year: 1997, Page(s):1465 - 1476
    Cited by:  Papers (43)  |  Patents (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (628 KB)

    Corresponding to any lossless codeword length function l, three universal lossy data compression schemes are presented: one is with a fixed rate, another is with a fixed distortion, and a third is with a fixed slope. The former two universal lossy data compression schemes are the generalization of Yang-Kieffer's (see ibid., vol.42, no.1, p.239-45, 1995) results to the general case of any lossless ... View full abstract»

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  • New good quasi-cyclic ternary and quaternary linear codes

    Publication Year: 1997, Page(s):1647 - 1650
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (132 KB)

    Let [n,k,d;q]-codes be linear codes of length n, dimension k and minimum Hamming distance d over GF(q). The following quasi-cyclic codes are constructed in this paper: [44,11,20;3], [55,11:26:3], [66,11,32;3], [48,12,21;3], [60,12,28;3], [56,13,24;3], [65,13,29;3], [56,14,23;3], [60,15,23;3], [64,16,25;3], [36,9,19;4], [90,9,55;4], [99,9,61;4], [30,10,14;4], [50,10,27;4], [55,10,30;4], [33,11,15;4... View full abstract»

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  • Is code equivalence easy to decide?

    Publication Year: 1997, Page(s):1602 - 1604
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (108 KB)

    We study the computational difficulty of deciding whether two matrices generate equivalent linear codes, i.e., codes that consist of the same codewords up to a fixed permutation on the codeword coordinates. We call this problem code equivalence. Using techniques from the area of interactive proofs, we show on the one hand, that under the assumption that the polynomial-time hierarchy does not colla... View full abstract»

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  • New extremal self-dual codes of lengths 42 and 44

    Publication Year: 1997, Page(s):1607 - 1612
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (204 KB)

    All extremal binary self-dual codes of lengths 42 and 44 which have an automorphism of order 5 with eight independent cycles are obtained up to equivalence. There are 109 inequivalent [42, 21, 8] codes with such an automorphism. All [44, 22, 8] codes that are obtained have 29 different weight enumerators View full abstract»

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  • The quadratic Gaussian CEO problem

    Publication Year: 1997, Page(s):1549 - 1559
    Cited by:  Papers (148)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (588 KB)

    A firm's CEO employs a team of L agents who observe independently corrupted versions of a data sequence {X(t)}t=1. Let R be the total data rate at which the agents may communicate information about their observations to the CEO. The agents are not allowed to convene. Berger, Zhang and Viswanathan (see ibid., vol.42, no.5, p.887-902, 1996) determined the asymptotic beh... View full abstract»

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  • Probabilistic crisscross error correction

    Publication Year: 1997, Page(s):1425 - 1438
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (776 KB)

    The crisscross error model in data arrays is considered, where the corrupted symbols are confined to a prescribed number of rows or columns (or both). Under the additional assumption that the corrupted entries are uniformly distributed over the channel alphabet, and by allowing a small decoding error probability, a coding scheme is presented where the redundancy can get close to one half the redun... View full abstract»

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  • Sequential prediction and ranking in universal context modeling and data compression

    Publication Year: 1997, Page(s):1697 - 1706
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (420 KB)

    Most state-of-the-art lossless image compression schemes use prediction followed by some form of context modeling. This might seem redundant at first, as the contextual information used for prediction is also available for building the compression model, and a universal coder will eventually learn the “predictive” patterns of the data. In this correspondence, we provide a format justif... View full abstract»

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  • Optimal multiplexing on a single link: delay and buffer requirements

    Publication Year: 1997, Page(s):1518 - 1535
    Cited by:  Papers (84)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (740 KB)

    This paper is motivated by the need to provide per-session quality of service guarantees in fast packet-switched networks. We address the problem of characterizing and designing scheduling policies that are optimal in the sense of minimizing buffer and/or delay requirements under the assumption of commonly accepted traffic constraints. We investigate buffer requirements under three typical memory ... View full abstract»

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  • On Diamond codes

    Publication Year: 1997, Page(s):1400 - 1411
    Cited by:  Papers (5)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (452 KB)

    A Diamond code is an error-correcting code obtained from two component codes. As in a product code, any symbol in a word of a Diamond code is checked by both component codes. However, the “code directions” for the component codes have been selected to minimize the memory that is required between successive decoding stages for the component codes. Diamond codes combine the error correct... View full abstract»

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Aims & Scope

IEEE Transactions on Information Theory publishes papers concerned with the transmission, processing, and utilization of information.

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Meet Our Editors

Editor-in-Chief
Frank R. Kschischang

Department of Electrical and Computer Engineering