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IEEE Transactions on Information Theory

Issue 5 • Sep 1997

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Displaying Results 1 - 25 of 46
  • Probabilistic crisscross error correction

    Publication Year: 1997, Page(s):1425 - 1438
    Cited by:  Papers (13)
    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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  • Tradeoff between source and channel coding

    Publication Year: 1997, Page(s):1412 - 1424
    Cited by:  Papers (94)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (636 KB)

    A fundamental problem in the transmission of analog information across a noisy discrete channel is the choice of channel code rate that optimally allocates the available transmission rate between lossy source coding and block channel coding. We establish tight bounds on the channel code rate that minimizes the average distortion of a vector quantizer cascaded with a channel coder and a binary-symm... 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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  • On an approximate eigenvector associated with a modulation code

    Publication Year: 1997, Page(s):1672 - 1678
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    Let S be a constrained system of finite type, described in terms of a labeled graph M of finite type. Furthermore, let C be an irreducible constrained system of finite type, consisting of the collection of possible code sequences of some finite-state-encodable, sliding-block-decodable modulation code for S. It is known that this code could then be obtained by state splitting, using a suitable appr... View full abstract»

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  • A practical method for approaching the channel capacity of constrained channels

    Publication Year: 1997, Page(s):1389 - 1399
    Cited by:  Papers (61)  |  Patents (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    A new coding technique is proposed that translates user information into a constrained sequence using very long codewords. Huge error propagation resulting from the use of long codewords is avoided by reversing the conventional hierarchy of the error control code and the constrained code. The new technique is exemplified by focusing on (d, k)-constrained codes. A storage-effective enumerative enco... View full abstract»

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  • Complementary reliability-based decodings of binary linear block codes

    Publication Year: 1997, Page(s):1667 - 1672
    Cited by:  Papers (14)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    This correspondence presents a hybrid reliability-based decoding algorithm which combines the reprocessing method based on the most reliable basis and a generalized Chase-type algebraic decoder based on the least reliable positions. It is shown that reprocessing with a simple additional algebraic decoding effort achieves significant coding gain. For long codes, the order of reprocessing required t... 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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  • Nonuniform sampling of bandlimited signals with polynomial growth on the real axis

    Publication Year: 1997, Page(s):1717 - 1721
    Cited by:  Papers (4)
    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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  • Some decomposable codes: the |a+x|b+x|a+b+x| construction

    Publication Year: 1997, Page(s):1663 - 1667
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    Codes with decomposable structure allow the use of multistage decoding procedures to achieve suboptimum bounded-distance error performance with reduced decoding complexity. This correspondence presents some new decomposable codes, including a class of distance-8 codes, that are constructed based on the |a+x|b+x|a+b+x| construction method. Some existing best codes are shown to be decomposable and h... 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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  • 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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  • On acceptance criterion for efficient successive errors-and-erasures decoding of Reed-Solomon and BCH codes

    Publication Year: 1997, Page(s):1477 - 1488
    Cited by:  Papers (7)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (728 KB)

    We describe an efficient algorithm for successive errors-and-erasures decoding of BCH codes. The decoding algorithm consists of finding all necessary error locator polynomials and errata evaluator polynomials, choosing the most appropriate error locator polynomial and errata evaluator polynomial, using these two polynomials to compute a candidate codeword for the decoder output, and testing the ca... View full abstract»

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  • The zero-guards algorithm for general minimum-distance decoding problems

    Publication Year: 1997, Page(s):1655 - 1658
    Cited by:  Papers (40)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (164 KB)

    We present some properties of an improved version of the zero-neighbors algorithm-the zero-guards algorithm. These properties can be used to find a zero-guards. A new decoding procedure using a zero-guards is also given View full abstract»

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  • Cryptographically resilient functions

    Publication Year: 1997, Page(s):1740 - 1747
    Cited by:  Papers (34)  |  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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  • A lower bound for ternary constant weight codes

    Publication Year: 1997, Page(s):1630 - 1632
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (124 KB)

    We derive a lower bound for ternary constant-weight codes with minimum Hamming distance three. The bound is similar to a bound for binary constant-weight codes with minimum distance four described by Graham and Sloane (1980). It improves upon the Gilbert (1952) bound and coincides asymptotically with the Johnson (1962) bound for fixed weight as the codeword length tends to infinity View full abstract»

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  • A hyperplane-based algorithm for the digital co-channel communications problem

    Publication Year: 1997, Page(s):1536 - 1548
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (648 KB)

    The relationship between the blind digital co-channel communications problem and the problem of finding a separating hyperplane in IRd is explored. A simple model for the blind digital co-channel communications problem is X=AS, where X is a known IR d×N matrix. A is an unknown full-rank IRd×d matrix, and S is an unknown full-rank d×N matrix with ... 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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  • 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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  • A suboptimal lossy data compression based on approximate pattern matching

    Publication Year: 1997, Page(s):1439 - 1451
    Cited by:  Papers (50)  |  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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  • On the effect of truncation length on the exact performance of a convolutional code

    Publication Year: 1997, Page(s):1678 - 1681
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (164 KB)

    In this correspondence, we first correct a mistake in Best et al. (1995) and then present a method to compute the exact probability of information bit error as a function of truncation length K for a rate 1/2, 2 state code, Finally, we generalize the method to compute the exact bit-error probability of the above convolutional code when the information bits are transmitted in blocks. The simulation... View full abstract»

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  • Constructions of nonlinear covering codes

    Publication Year: 1997, Page(s):1639 - 1647
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (516 KB)

    Constructions of nonlinear covering codes are given. Using any nonlinear starting code of covering radius R⩾2 these constructions form an infinite family of codes with the same covering radius. A nonlinear code is treated as a union of cosets of a linear code. New infinite families of nonlinear covering codes are obtained. Concepts of R,l-objects, R,l-partitions, and R,l-length are described f... View full abstract»

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  • Covering numbers for real-valued function classes

    Publication Year: 1997, Page(s):1721 - 1724
    Cited by:  Papers (16)
    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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  • 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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  • 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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  • A lower bound on the undetected error probability and strictly optimal codes

    Publication Year: 1997, Page(s):1489 - 1502
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (824 KB)

    Error detection is a simple technique used in various communication and memory systems to enhance reliability. We study the probability that a q-ary (linear or nonlinear) block code of length n and size M fails to detect an error. A lower bound on this undetected error probability is derived in terms of q, n, and M. The new bound improves upon other bounds mentioned in the literature, even those t... 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
Prakash Narayan 

Department of Electrical and Computer Engineering