IEEE Transactions on Information Theory

Volume 39 Issue 4 • July 1993

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Displaying Results 1 - 25 of 41
  • Common randomness in information theory and cryptography. I. Secret sharing

    Publication Year: 1993, Page(s):1121 - 1132
    Cited by:  Papers (631)  |  Patents (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1281 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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  • Vector quantization with complexity costs

    Publication Year: 1993, Page(s):1133 - 1145
    Cited by:  Papers (57)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1702 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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  • Strong universal consistency of neural network classifiers

    Publication Year: 1993, Page(s):1146 - 1151
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (587 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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  • On the density of phase-space expansions

    Publication Year: 1993, Page(s):1152 - 1156
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (398 KB)

    Phase-space decompositions for signals of finite energy have been used to formulate the intuitive but elusive idea that frequency content of a signal can vary with time as the signal evolves. The decompositions consist of subdividing the time and frequency axes into certain ranges and expanding signals stably in a two-parameter basis of fixed functions of time, in which the (k,m)th coefficient is ... View full abstract»

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  • Wavelet transforms associated with finite cyclic groups

    Publication Year: 1993, Page(s):1157 - 1166
    Cited by:  Papers (48)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (966 KB)

    Multiresolution analysis via decomposition on wavelet bases has emerged as an important tool in the analysis of signals and images when these objects are viewed as sequences of complex or real numbers. An important class of multiresolution decompositions are the Laplacian pyramid schemes, in which the resolution is successively halved by recursively low-pass filtering the signal under analysis and... View full abstract»

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  • Alphabet-constrained vector quantization

    Publication Year: 1993, Page(s):1167 - 1179
    Cited by:  Papers (9)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1273 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 simulations usin... 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 (22)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1548 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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  • 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 (643 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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  • 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 (1495 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 decoding s... 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 (49)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1204 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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  • Multilevel codes for unequal error protection

    Publication Year: 1993, Page(s):1234 - 1248
    Cited by:  Papers (124)  |  Patents (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1231 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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  • Correcting dependent errors in sequences generated by finite-state processes

    Publication Year: 1993, Page(s):1249 - 1260
    Cited by:  Papers (17)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1306 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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  • Universal decoding for memoryless Gaussian channels with a deterministic interference

    Publication Year: 1993, Page(s):1261 - 1269
    Cited by:  Papers (31)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (722 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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  • A measure of relative entropy between individual sequences with application to universal classification

    Publication Year: 1993, Page(s):1270 - 1279
    Cited by:  Papers (67)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (876 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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  • Universal schemes for sequential decision from individual data sequences

    Publication Year: 1993, Page(s):1280 - 1292
    Cited by:  Papers (46)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1372 KB)

    Sequential decision algorithms are investigated in relation to a family of additive performance criteria for individual data sequences. Simple universal sequential schemes are known, under certain conditions, to approach optimality uniformly as fast as n/sup -1/ log n, where n is the sample size. For the case of finite-alphabet observations, the class of schemes that can be implemented by finite-s... View full abstract»

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  • Proper complex random processes with applications to information theory

    Publication Year: 1993, Page(s):1293 - 1302
    Cited by:  Papers (527)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (964 KB)

    The covariance of complex random variables and processes, when defined consistently with the corresponding notion for real random variables, is shown to be determined by the usual complex covariance together with a quantity called the pseudo-covariance. A characterization of uncorrelatedness and wide-sense stationarity in terms of covariance and pseudo-covariance is given. Complex random variables... 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 (741 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 Sigma is a shift of finite type and S is a sofic system with k/n=h(S)/h( Sigma ), where h denotes entropy, there is a noncatastrophic finite-state invertible code from Sigma to S at rate k:n if Sigma and S satisfy a certain algebrai... View full abstract»

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  • On the capacity of a cascade of channels

    Publication Year: 1993, Page(s):1310 - 1321
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1177 KB)

    A class of information-theoretic problems is introduced that deals with systems in which information is transmitted through a series of noisy channels with limited or no processing between channels. Some basic questions that arise in such systems are examined in detail. The effects of ordering of the channels on overall capacity and the characteristics that cause channels to have high capacity whe... View full abstract»

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  • Partition function estimation of Gibbs random field images using Monte Carlo simulations

    Publication Year: 1993, Page(s):1322 - 1332
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1008 KB)

    A Monte Carlo simulation technique for estimating the partition function of a general Gibbs random field image is proposed. By expressing the partition function as an expectation, an importance sampling approach for estimating it using Monte Carlo simulations is developed. As expected, the resulting estimators are unbiased and consistent. Computations can be performed iteratively by using simple M... 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 (54)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2161 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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  • Markov modeling for Bayesian restoration of two-dimensional layered structures

    Publication Year: 1993, Page(s):1356 - 1373
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1845 KB)

    Bayesian estimation of two-dimensional stratified structures is described. The major point addressed is the derivation of a statistical prior model that adequately describes such layered media. This problem is of interest in applications in which the data are generally processed in one dimension only. In order to take local interactions into account, a Markovian description is used. The model is d... View full abstract»

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  • Asymptotic results for maximum likelihood estimation with an array of sensors

    Publication Year: 1993, Page(s):1374 - 1385
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1173 KB)

    In many cases, the maximum likelihood (ML) estimator is consistent and asymptotically normal with covariance equal to the inverse of the Fisher's information matrix. It does not follow, though, that the covariance of the ML estimator approaches the Cramer-Rao lower bound as the sample size increases. However, it is possible to draw such a conclusion for the adaptive array problem in which directio... View full abstract»

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  • Bounds on the Bayes and minimax risk for signal parameter estimation

    Publication Year: 1993, Page(s):1386 - 1394
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (638 KB)

    In estimating the parameter theta from a parametrized signal problem (with 0<or= theta <or=L) observed through Gaussian white noise, four useful and computable lower bounds for the Bayes risk are developed. For problems with different L and different signal to noise ratios, some bounds are superior to others. The lower bound obtained from taking the maximum of the four, serves not only as a ... 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 (394 KB)

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

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

    Publication Year: 1993, Page(s):1398 - 1401
    Cited by:  Papers (82)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (438 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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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