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IEEE Transactions on Information Theory

Issue 4 • Date Jul 1993

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Displaying Results 1 - 25 of 41
  • Vector quantization with complexity costs

    Publication Year: 1993, Page(s):1133 - 1145
    Cited by:  Papers (54)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1528 KB)

    Vector quantization is a data compression method by which a set of data points is encoded by a reduced set of reference vectors: the codebook. A vector quantization strategy is discussed that jointly optimizes distortion errors and the codebook complexity, thereby determining the size of the codebook. A maximum entropy estimation of the cost function yields an optimal number of reference vectors, ... View full abstract»

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  • Multistage decoding of multilevel block M-PSK modulation codes and its performance analysis

    Publication Year: 1993, Page(s):1204 - 1218
    Cited by:  Papers (26)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1288 KB)

    Multistage decoding of multilevel block multilevel phase-shift keying (M-PSK) modulation codes for the additive white Gaussian noise (AWGN) channel is investigated. Several types of multistage decoding, including a suboptimum soft-decision decoding scheme, are devised and analyzed. Upper bounds on the probability of an incorrect decoding of a code are derived for the proposed multistage d... View full abstract»

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  • Common randomness in information theory and cryptography. I. Secret sharing

    Publication Year: 1993, Page(s):1121 - 1132
    Cited by:  Papers (414)  |  Patents (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1096 KB)

    As the first part of a study of problems involving common randomness at distance locations, information-theoretic models of secret sharing (generating a common random key at two terminals, without letting an eavesdropper obtain information about this key) are considered. The concept of key-capacity is defined. Single-letter formulas of key-capacity are obtained for several models, and bounds to ke... View full abstract»

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  • Universal decoding for memoryless Gaussian channels with a deterministic interference

    Publication Year: 1993, Page(s):1261 - 1269
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (612 KB)

    A universal decoding procedure is proposed for memoryless Gaussian channels with deterministic interfering signals from a certain class. The proposed decoder is universal in the sense that it is independent of the channel parameters and the unknown interfering signal, and, at the same time, attains the same random coding error exponent as the optimal maximum likelihood (ML) decoder, which utilizes... View full abstract»

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  • Covering radius, codimension, and dual-distance width

    Publication Year: 1993, Page(s):1195 - 1203
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (544 KB)

    Upper bounds on the covering radius of codes with a given cardinality and a given dual-distance width are derived. Using an entirely new method, some results published by C. Delorme and P. Sole (1991) for linear codes are generalized, and results are derived for unrestricted codes that have no previous analogue. For some classes of codes, when the parameters lie within certain intervals, results i... View full abstract»

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  • Correcting dependent errors in sequences generated by finite-state processes

    Publication Year: 1993, Page(s):1249 - 1260
    Cited by:  Papers (15)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1132 KB)

    A new channel model and channel inversion algorithm are presented for correcting symbol sequences that have been corrupted by an unknown combination of known fault mechanisms. The algorithm is similar to the Viterbi algorithm in that it is suitable for situations in which the uncorrupted data string is generated by a known finite-state process, but it is more versatile in that it can correct a muc... View full abstract»

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  • Nonparametric maximum entropy

    Publication Year: 1993, Page(s):1409 - 1413
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (540 KB)

    The standard maximum entropy method developed by J.P. Burg (1967) and the resulting autoregressive model have been widely applied to spectrum estimation and prediction. A generalization of the maximum entropy formalism in a nonparametric setting is presented, and the class of the resulting solutions is identified to be a class of Markov processes. The proof is based on a string of information theo... View full abstract»

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  • On the design of an optimal quantizer

    Publication Year: 1993, Page(s):1180 - 1194
    Cited by:  Papers (11)  |  Patents (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1312 KB)

    The problem of designing an optimal quantizer with a fixed number of levels for a wide class of error weighting functions and an arbitrary distribution function is discussed. The existence of an optimal quantizer is proved, and a two-stage algorithm for its design is suggested. In this algorithm, at the first stage, Lloyd's iterative Method I is applied for reducing the region where, at the second... View full abstract»

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  • Maximum likelihood decoding of the Leech lattice

    Publication Year: 1993, Page(s):1435 - 1444
    Cited by:  Papers (25)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (804 KB)

    An algorithm for maximum likelihood decoding of the Leech lattice is presented. The algorithm involves projecting the points of the Leech lattice directly onto the codewords of the (6,3,4) quaternary code-the hexacode. Projection on the hexacode induces a partition of the Leech lattice into four cosets of a certain sublattice 24. Such a partition into cosets enables maximum likelihood decoding of ... View full abstract»

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  • An algorithm for the k-error linear complexity of binary sequences with period 2n

    Publication Year: 1993, Page(s):1398 - 1401
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    Certain applications require pseudo-random sequences which are unpredictable in the sense that recovering more of the sequence from a short segment must be computationally infeasible. It is shown that linear complexity is useful in determining such sequences. A generalized linear complexity that has application to the security of stream ciphers is proposed, and an efficient algorithm is given for ... View full abstract»

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  • Multilevel codes for unequal error protection

    Publication Year: 1993, Page(s):1234 - 1248
    Cited by:  Papers (116)  |  Patents (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1056 KB)

    Two combined unequal error protection (UEP) coding and modulation schemes are proposed. The first method multiplexes different coded signal constellations, with each coded constellation providing a different level of error protection. In this method, a codeword specifies the multiplexing rule and the choice of the codeword from a fixed codebook is used to convey additional important information. T... View full abstract»

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  • On loss functions which minimize to conditional expected values and posterior probabilities

    Publication Year: 1993, Page(s):1404 - 1408
    Cited by:  Papers (22)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    A loss function, or objective function, is a function used to compare parameters when fitting a model to data. The loss function gives a distance between the model output and the desired output. Two common examples are the squared-error loss function and the cross entropy loss function. Minimizing the mean-square error loss function is equivalent to minimizing the mean square difference between th... View full abstract»

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  • The entropy of Markov trajectories

    Publication Year: 1993, Page(s):1418 - 1421
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (244 KB)

    The idea of thermodynamic depth put forth by S. Lloyd and H. Pagels (1988) requires the computation of the entropy of Markov trajectories. Toward this end, the authors consider an irreducible finite state Markov chain with transition matrix P and associated entropy rate H(X)=-Σi,j μiPij log Pij where ... View full abstract»

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  • Noncausal Gauss Markov random fields: parameter structure and estimation

    Publication Year: 1993, Page(s):1333 - 1355
    Cited by:  Papers (51)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1884 KB)

    The parameter structure of noncausal homogeneous Gauss Markov random fields (GMRF) defined on finite lattices is studied. For first-order (nearest neighbor) and a special class of second-order fields, a complete characterization of the parameter space and a fast implementation of the maximum likelihood estimator of the field parameters are provided. For general higher order fields, tight bounds fo... View full abstract»

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  • Alphabet-constrained vector quantization

    Publication Year: 1993, Page(s):1167 - 1179
    Cited by:  Papers (8)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1100 KB)

    Alphabet-constrained rate-distortion theory is extended to coding of sources with memory. Two different cases are considered: when only the size of the codebook is constrained and when the codevector values are also held fixed. For both cases, nth-order constrained-alphabet rate-distortion functions are defined and a convergent algorithm for their evaluation is presented. Specific simulat... View full abstract»

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  • Sliding block codes between constrained systems

    Publication Year: 1993, Page(s):1303 - 1309
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (620 KB)

    The construction of finite-state codes between constrained systems called sofic systems introduced by R. Karabed and B. Marcus (1988) is continued. It is shown that if Σ is a shift of finite type and S is a sofic system with k/n=h(S )/h(Σ), where h denotes entropy, there is a noncatastrophic finite-state invertible code fro... View full abstract»

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  • On the nonperiodic cyclic equivalence classes of Reed-Solomon codes

    Publication Year: 1993, Page(s):1431 - 1434
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    Picking up exactly one member from each of the nonperiodic cyclic equivalence classes of an (n, k+1) Reed-Solomon code E over GF(q) gives a code, E", which has bounded Hamming correlation values and the self-synchronizing property. The exact size of E" is shown to be (1/n) Σd|n μ(d)q1+kd... View full abstract»

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  • On the realization of band-limited power spectra from partial covariance sequence

    Publication Year: 1993, Page(s):1395 - 1397
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    The set M(Ω) of all (discrete-time) power spectra supported on a known interval [-Ω, Ω], (with Ω<π) and whose first N+1 correlation coefficients coincide with a given sequence (γn)n=0,N is characterized. By using the results related to the trigonometric moment problem, it is shown that the positive real functions asso... View full abstract»

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  • Random infinite trees and supercritical behavior of collision resolution algorithms

    Publication Year: 1993, Page(s):1460 - 1465
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (488 KB)

    An analytical evaluation is given of the behavior of the free access stack algorithm when the input load, a Poisson flow of λ packet per slot, is above the maximum throughput achievable by the protocol (within 0.360177 packet per slot) under an infinite population model. In particular, the marginal output stream that the system sustains on the channel is analytically and quantitatively deri... View full abstract»

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  • Strong universal consistency of neural network classifiers

    Publication Year: 1993, Page(s):1146 - 1151
    Cited by:  Papers (26)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (496 KB)

    In statistical pattern recognition, a classifier is called universally consistent if its error probability converges to the Bayes-risk as the size of the training data grows for all possible distributions of the random variable pair of the observation vector and its class. It is proven that if a one-layered neural network with properly chosen number of nodes is trained to minimize the empirical ri... View full abstract»

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  • A linear algebra approach to minimal convolutional encoders

    Publication Year: 1993, Page(s):1219 - 1233
    Cited by:  Papers (48)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1032 KB)

    The authors review the work of G.D. Forney, Jr., on the algebraic structure of convolutional encoders upon which some new results regarding minimal convolutional encoders rest. An example is given of a basic convolutional encoding matrix whose number of abstract states is minimal over all equivalent encoding matrices. However, this encoding matrix can be realized with a minimal number of memory el... View full abstract»

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  • A measure of relative entropy between individual sequences with application to universal classification

    Publication Year: 1993, Page(s):1270 - 1279
    Cited by:  Papers (34)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (744 KB)

    A new notion of empirical informational divergence (relative entropy) between two individual sequences is introduced. If the two sequences are independent realizations of two finite-order, finite alphabet, stationary Markov processes, the empirical relative entropy converges to the relative entropy almost surely. This empirical divergence is based on a version of the Lempel-Ziv data compression al... View full abstract»

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  • Nonbinary codes correcting localized errors

    Publication Year: 1993, Page(s):1413 - 1416
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    A recursive construction of asymptotically dense codes correcting a constant number of localized errors is examined. The codes overcome difficulties for a particular case with an asymptotic Hamming bound in which the number of errors increases linearly with the length of codes. It is shown that this method is applicable to both binary and nonbinary cases View full abstract»

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  • A coding scheme for single peak-shift correction in (d, k)-constrained channels

    Publication Year: 1993, Page(s):1444 - 1450
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (712 KB)

    A two step coding scheme for peak-shift correction in (d, k)-constrained sequences is described. The first step is based on q-ary (q=k-d+1 is a prime) block codes that allow correction of specific types of double errors caused by single peak-shifts. The second step is a simple conversion of q-ary symbols to binary strings of the type 0... View full abstract»

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  • Kullback-Leibler information measure for studying convergence rates of densities and distributions

    Publication Year: 1993, Page(s):1401 - 1404
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (308 KB)

    The Kullback-Leibler (KL) information measure l(f1:f2) is proposed as an index for studying rates of convergence of densities and distribution functions. To this end, upper bounds in terms of l(f 1:f2) for several distance functions for densities and for distribution functions are obtained. Many illus... 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