IEEE Transactions on Information Theory

Volume 45 Issue 4 • May 1999

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Displaying Results 1 - 25 of 37
  • Fast universal coding with context models

    Publication Year: 1999, Page(s):1065 - 1071
    Cited by:  Papers (10)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (157 KB)

    A universal code using context models is constructed, which is optimal in the strong sense that the mean per symbol code length approaches asymptotically the entropy of any data generating tree machine at the fastest possible rate. The number of coding operations required is O (n log log n) for a string of length n, which is much less than in the earlier codes using context models. This is made po... View full abstract»

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  • Entropy computations via analytic depoissonization

    Publication Year: 1999, Page(s):1072 - 1081
    Cited by:  Papers (39)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (290 KB)

    We investigate the basic question of information theory, namely, evaluation of Shannon entropy, and a more general Renyi (1961) entropy, for some discrete distributions (e.g., binomial, negative binomial, etc.). We aim at establishing analytic methods (i.e., those in which complex analysis plays a pivotal role) for such computations which often yield estimates of unparalleled precision. The main a... View full abstract»

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  • Asymptotic performance of vector quantizers with a perceptual distortion measure

    Publication Year: 1999, Page(s):1082 - 1091
    Cited by:  Papers (35)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (288 KB)

    Gersho's (1979) bounds on the asymptotic performance of vector quantizers are valid for vector distortions which are powers of the Euclidean norm. Yamada, Tazaki, and Gray (1980) generalized the results to distortion measures that are increasing functions of the norm of their argument. In both cases, the distortion is uniquely determined by the vector quantization error, i.e., the Euclidean differ... View full abstract»

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  • On the redundancy of lossy source coding with abstract alphabets

    Publication Year: 1999, Page(s):1092 - 1110
    Cited by:  Papers (35)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (619 KB)

    The redundancy problem of lossy source coding with abstract source and reproduction alphabets is considered. For coding at a fixed rate level, it is shown that for any fixed rate R>0 and any memoryless abstract alphabet source P satisfying some mild conditions, there exists a sequence {C/sub n/}/sub n=1//sup /spl infin// of block codes at the rate R such that the distortion redundancy of C/sub ... View full abstract»

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  • Distributed source coding for satellite communications

    Publication Year: 1999, Page(s):1111 - 1120
    Cited by:  Papers (86)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (321 KB)

    Inspired by mobile satellite communications systems, we consider a source coding system which consists of multiple sources, multiple encoders, and multiple decoders. Each encoder has access to a certain subset of the sources, each decoder has access to certain subset of the encoders, and each decoder reconstructs a certain subset of the sources almost perfectly. The connectivity between the source... View full abstract»

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  • Combined array processing and space-time coding

    Publication Year: 1999, Page(s):1121 - 1128
    Cited by:  Papers (339)  |  Patents (42)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (171 KB)

    The information capacity of wireless communication systems may be increased dramatically by employing multiple transmit and receive antennas. The goal of system design is to exploit this capacity in a practical way. An effective approach to increasing data rate over wireless channels is to employ space-time coding techniques appropriate to multiple transmit antennas. These space-time codes introdu... View full abstract»

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  • Non-Gaussian noise models in signal processing for telecommunications: new methods an results for class A and class B noise models

    Publication Year: 1999, Page(s):1129 - 1149
    Cited by:  Papers (344)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (662 KB)

    The subject here is generalized (i.e., non-Gaussian) noise models, and specifically their first-order probability density functions (PDFs). Attention is focused primarily on the author's canonical statistical-physical Class A and Class B models. In particular, Class A noise describes the type of electromagnetic interference (EMI) often encountered in telecommunication applications, where this ambi... View full abstract»

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  • Maximum entropy and robust prediction on a simplex

    Publication Year: 1999, Page(s):1150 - 1164
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (374 KB)

    The related problems of (finite-length) robust prediction and maximizing spectral entropy over a simplex of covariance matrices are considered. General properties of iterative solutions of these problems are developed, and monotone convergence proofs are presented for two algorithms that provide such solutions. The analogous problems for simplexes of spectral densities are also considered. View full abstract»

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  • Universal schemes for learning the best nonlinear predictor given the infinite past and side information

    Publication Year: 1999, Page(s):1165 - 1185
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (752 KB)

    Let {X/sub t/} be a real-valued time series. The best nonlinear predictor of X/sub 0/ given the infinite past X/sub -/spl infin///sup -1/ in the least squares sense, is equal to the conditional mean E{X/sub 0/|X/sub -/spl infin///sup -1/}. Previously, it has been shown that certain predictors based on growing segments of past observations converge to the best predictor given the infinite past when... View full abstract»

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  • Constructions of algebraic-geometry codes

    Publication Year: 1999, Page(s):1186 - 1193
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (231 KB)

    Based on curves over finite fields with many rational points, we present two constructions of linear codes from local expansions of functions at a fixed rational point. It turns out that codes from our constructions have the same bound on their parameters as Goppa's (1981) geometry codes. Furthermore, we prove that our second construction is equivalent to Goppa's construction. Finally, an addition... View full abstract»

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  • Type II codes, even unimodular lattices, and invariant rings

    Publication Year: 1999, Page(s):1194 - 1205
    Cited by:  Papers (62)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (361 KB)

    We study self-dual codes over the ring Z/sub 2k/ of the integers modulo 2k with relationships to even unimodular lattices, modular forms, and invariant rings of finite groups. We introduce Type II codes over Z/sub 2k/ which are closely related to even unimodular lattices, as a remarkable class of self-dual codes and a generalization of binary Type II codes. A construction of even unimodular lattic... View full abstract»

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  • Upper bounds on the size of quantum codes

    Publication Year: 1999, Page(s):1206 - 1215
    Cited by:  Papers (31)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (240 KB)

    This paper is concerned with bounds for quantum error-correcting codes. Using the quantum MacWilliams (1972, 1977) identities, we generalize the linear programming approach from classical coding theory to the quantum case. Using this approach, we obtain Singleton-type, Hamming-type, and the first linear-programming-type bounds for quantum codes. Using the special structure of linear quantum codes,... View full abstract»

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  • Cryptographic distinguishability measures for quantum-mechanical states

    Publication Year: 1999, Page(s):1216 - 1227
    Cited by:  Papers (261)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (253 KB)

    This paper, mostly expository in nature, surveys four measures of distinguishability for quantum-mechanical states. This is done from the point of view of the cryptographer with a particular eye on applications in quantum cryptography. Each of the measures considered is rooted in an analogous classical measure of distinguishability for probability distributions: namely, the probability of an ident... View full abstract»

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  • Optimal binary one-error-correcting codes of length 10 have 72 codewords

    Publication Year: 1999, Page(s):1229 - 1231
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (80 KB)

    The maximum number of codewords in a binary code with length n and minimum distance d is denoted by A(n, d). By construction it is known that A(10, 3)/spl ges/72 and A(11, 3)/spl ges/144. These bounds have long been conjectured to be the exact values. This is here proved by classifying various codes of smaller length and lengthening these using backtracking and isomorphism rejection. There are 562... View full abstract»

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  • Construction of an extremal self-dual code of length 62

    Publication Year: 1999, Page(s):1232 - 1233
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (107 KB)

    We construct an extremal singly-even self-dual [62, 31, 12] code. The existence of such a self-dual code was not previously known. Combined with known results, the above code also determines all lengths for which there are self-dual codes with minimum weight 12. View full abstract»

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  • Constructions of intersecting codes

    Publication Year: 1999, Page(s):1234 - 1237
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (154 KB)

    New constructions of binary linear intersecting codes are presented. Some codes with high distances are shown to be intersecting. View full abstract»

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  • On some cosets of the first-order Reed-Muller code with high minimum weight

    Publication Year: 1999, Page(s):1237 - 1243
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (310 KB)

    We study a family of particular cosets of the first-order Reed-Muller code R(1,m): those generated by special codewords, the idempotents. Thus we obtain new maximal weight distributions of cosets of R(1,7) and 84 distinct almost maximal weight distributions of cosets of R(1,9), that is, with minimum weight 240. This leads to crypotographic applications in the context of stream ciphers. View full abstract»

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  • Two recursive algorithms for computing the weight distribution of certain irreducible cyclic codes

    Publication Year: 1999, Page(s):1244 - 1249
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (221 KB)

    Two recursive algorithms for computing the weight distributions of certain binary irreducible cyclic codes of length n in the so-called index 2 case are presented. The running times of these algorithms are smaller than O(log/sup 2/r) where r=2/sup m/ and n is a factor of r-1. View full abstract»

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  • Cyclic codes and self-dual codes over F/sub 2/+uF/sub 2/

    Publication Year: 1999, Page(s):1250 - 1255
    Cited by:  Papers (85)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (261 KB)

    We introduce linear cyclic codes over the ring F/sub 2/+uF/sub 2/={0,1,u,u~=u+1}, where u/sup 2/=0 and study them by analogy with the Z/sub 4/ case. We give the structure of these codes on this new alphabet. Self-dual codes of odd length exist as in the case of Z/sub 4/-codes. Unlike the Z/sub 4/ case, here free codes are not interesting. Some nonfree codes give rise to optimal binary linear codes... View full abstract»

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  • Further results on generalized Hamming weights for Goethals and Preparata codes over Z/sub 4/

    Publication Year: 1999, Page(s):1255 - 1258
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    This article contains results on the generalized Hamming weights (GHW) for the Goethals and Preparata codes over Z/sub 4/. We give an upper bound on the rth generalized Hamming weights d/sub r/(m,j) for the Goethals code G/sub m/(j) of length 2/sup m/ over Z/sub 4/, when m is odd. We also determine d/sub 3.5/(m,j) exactly. The upper bound is shown to be tight up to r=3.5. Furthermore, we determine... View full abstract»

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  • New upper bounds on generalized weights

    Publication Year: 1999, Page(s):1258 - 1263
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (235 KB)

    We derive new asymptotic upper bounds on the generalized weights of a binary linear code of a given size. We also prove some asymptotic results on the distance distribution of binary codes. View full abstract»

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  • New classes of cyclic extended Goppa codes

    Publication Year: 1999, Page(s):1264 - 1266
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (108 KB)

    We give a condition for a "classical" Goppa (1970) code to have a cyclic extension. This condition follows from the properties of the semilinear automorphism group of the corresponding generalized Reed-Solomon codes. Using this condition, we can construct not only all the known Goppa codes with a cyclic extension, but also new families. View full abstract»

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  • Sequences with almost perfect linear complexity profiles and curves over finite fields

    Publication Year: 1999, Page(s):1267 - 1270
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (132 KB)

    For stream ciphers, we need to generate pseudorandom sequences which are of properties of unpredictability and randomness. A important measure of unpredictability and randomness is the linear complexity profile (l.c.p.) l/sub a/(n) of a sequence a. A sequence a is called almost perfect if the l.c.p. is l/sub a/(n)=n/2+O(1). Based on curves over finite fields, we present a method to construct almos... View full abstract»

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  • Almost perfect nonlinear power functions on GF(2/sup n/): the Welch case

    Publication Year: 1999, Page(s):1271 - 1275
    Cited by:  Papers (98)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (178 KB)

    We summarize the state of the classification of almost perfect nonlinear (APN) power functions x/sup d/ on GF(2/sup n/) and contribute two new cases. To prove these cases we derive new permutation polynomials. The first case supports a well-known conjecture of Welch stating that for odd n=2m+1, the power function x/sup 2m+3/ is even maximally nonlinear or, in other terms, that the crosscorrelation... View full abstract»

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  • Periodic binary sequences with the "trinomial property"

    Publication Year: 1999, Page(s):1276 - 1279
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (191 KB)

    Periodic binary sequences with the "trinomial property" are considered. Some necessary and sufficient conditions for "trinomial pairs" of a nonlinear sequence of period 2/sup n/-1 as well as classifications for trinomial pairs are derived. Complete searches for trinomial pairs of sequences have been completed for 3/spl les/n/spl les/17. We list them here for n/spl les/12. 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.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Alexander Barg

Department of Electrical and Computer Engineering and the Institute for Systems Research, University of Maryland

email: abarg-ittrans@ece.umd.edu