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IEEE Transactions on Information Theory

Issue 2 • Mar 1998

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Displaying Results 1 - 25 of 47
  • The shape of low excursions of the envelope of a signal plus noise

    Publication Year: 1998, Page(s):882 - 886
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (200 KB)

    Like low excursions of the envelope of narrowband noise, those of the sum of a signal plus narrowband noise are hyperbolic in shape if the signal-to-noise ratio r is not high. When r≫1, low excursions of the envelope are hyperbolic if the signal is frequency-modulated but have a quartic shape with one or two minima if it is not. This article illuminates various aspects of FM clicks View full abstract»

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  • Systematic lossy source/channel coding

    Publication Year: 1998, Page(s):564 - 579
    Cited by:  Papers (156)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (544 KB)

    The fundamental limits of “systematic” communication are analyzed. In systematic transmission, the decoder has access to a noisy version of the uncoded raw data (analog or digital). The coded version of the data is used to reduce the average reproduced distortion D below that provided by the uncoded systematic link and/or increase the rate of information transmission. Unlike the case o... View full abstract»

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  • An asymptotic analysis of DS/SSMA communication systems with general linear modulation and error control coding

    Publication Year: 1998, Page(s):870 - 881
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (468 KB)

    We investigate direct-sequence spread-spectrum multiple-access (DS/SSMA) communication systems with general linear modulation and error control coding. By the central limit theorem for martingale difference arrays, it is proved that under general conditions, the overall multiple-access interference (MAI) across different symbol intervals tends to a jointly complex Gaussian random vector as both th... View full abstract»

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  • Resolvability theory for the multiple-access channel

    Publication Year: 1998, Page(s):472 - 487
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1056 KB)

    We study the randomness needed for approximating the output distribution of a multiple-access channel, where the original input processes are independent of each other. The approximation is achieved by simulating (possibly alternative) input processes at each of the entries, where the sources of randomness available for the simulators are independent of each other, and the simulators do not cooper... View full abstract»

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  • Information and control: matching channels

    Publication Year: 1998, Page(s):542 - 563
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1268 KB)

    The transmission problem for noisy channels is usually studied under the condition that the decoding error probability λ is small and is sometimes studied under the condition that λ=0. Here we just require that λ<1 and obtain a problem which is equivalent to a coding problem with small λ for the “deterministic matching channel.” In this new model, a coope... View full abstract»

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  • A detection optimal min-max test for transient signals

    Publication Year: 1998, Page(s):866 - 869
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (168 KB)

    Page's (1954) test is optimal for detecting a permanent change in distribution, in the sense that it minimizes the worst case average delay to detection given an average distance between false alarms. When used to detect transient signals, however, it in fact becomes the generalized likelihood ratio test (GLRT). Since a GLRT is in almost all cases ad hoc, Page's test used as such cannot be said to... View full abstract»

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  • Some structural properties of convolutional codes over rings

    Publication Year: 1998, Page(s):839 - 845
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    Convolutional codes over rings have been motivated by phase-modulated signals. Some structural properties of the generator matrices of such codes are presented. Successively stronger notions of the invertibility of generator matrices are studied, and a new condition for a convolutional code over a ring to be systematic is given and shown to be equivalent to a condition given by Massey and Mittelho... View full abstract»

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  • Source codes as random number generators

    Publication Year: 1998, Page(s):462 - 471
    Cited by:  Papers (26)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (440 KB)

    A random number generator generates fair coin flips by processing deterministically an arbitrary source of nonideal randomness. An optimal random number generator generates asymptotically fair coin flips from a stationary ergodic source at a rate of bits per source symbol equal to the entropy rate of the source. Since optimal noiseless data compression codes produce incompressible outputs, it is n... View full abstract»

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  • Density estimation from an individual numerical sequence

    Publication Year: 1998, Page(s):537 - 541
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (264 KB)

    This paper considers estimation of a univariate density from an individual numerical sequence. It is assumed that (1) the limiting relative frequencies of the numerical sequence are governed by an unknown density, and (2) there is a known upper bound for the variation of the density on an increasing sequence of intervals. A simple estimation scheme is proposed, and is shown to be L1 con... View full abstract»

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  • Typical error pattern recovery of the Hopfield memory under error-tolerant conditions

    Publication Year: 1998, Page(s):861 - 865
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (220 KB)

    We lower-bound the error-correcting capabilities of the Hopfield (1982) network under error-tolerant conditions, given some distorted version of a fundamental memory with a random (typical) error pattern. Our main result is that for any sufficiently small α, and for any ρ<1/2, a Hopfield memory with n neurons can store αn fundamental memories, such that the following is satisfie... View full abstract»

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  • Some new extremal self-dual codes with lengths 44, 50, 54, and 58

    Publication Year: 1998, Page(s):809 - 812
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    We construct extremal self-dual codes with lengths 44, 50, 54, and 58. They have weight enumerators for which extremal codes were previously not known to exist. Two methods are used for constructing the codes using self dual codes of same or smaller length. To obtain the codes we use a combinatorial optimization search View full abstract»

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  • A tight upper bound on discrete entropy

    Publication Year: 1998, Page(s):775 - 778
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (152 KB)

    The standard upper bound on discrete entropy was derived based on the differential entropy bound for continuous random variables. A tighter discrete entropy bound is derived using the transformation formula of Jacobi theta function. The new bound is applicable only when the probability mass function of the discrete random variable satisfies certain conditions. Its application to the class of binom... View full abstract»

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  • Systematic feed-forward convolutional encoders are better than other encoders with an M-algorithm decoder

    Publication Year: 1998, Page(s):831 - 838
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    Consider nonbacktracking convolutional decoders that keep a fixed number of trellis survivors. It is shown that the error performance of these depends on the early part of the distance profile and on the number of survivors kept, and not on the free distance or the details of the code generators. Particularly, the encoder may be feedforward systematic without loss. Furthermore, this kind of encode... View full abstract»

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  • On a new class of codes for identifying vertices in graphs

    Publication Year: 1998, Page(s):599 - 611
    Cited by:  Papers (165)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (636 KB)

    We investigate a new class of codes for the optimal covering of vertices in an undirected graph G such that any vertex in G can be uniquely identified by examining the vertices that cover it. We define a ball of radius t centered on a vertex υ to be the set of vertices in G that are at distance at most t from υ. The vertex υ is then said to cover itself and every other vertex in the... View full abstract»

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  • The information-theoretic capacity of discrete-time queues

    Publication Year: 1998, Page(s):446 - 461
    Cited by:  Papers (47)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (780 KB)

    The information-theoretic capacity of continuous-time queues was analyzed recently by Anantharam and Verdu (see ibid. vol.42, p.4-18, 1996). Along similar lines, we analyze the information-theoretic capacity of two models of discrete-time queues. The first model has single packet arrivals and departures in a time slot and independent packet service times, and is the discrete-time analog of the con... View full abstract»

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  • Asymptotic multiuser efficiencies for decision-directed multiuser detectors

    Publication Year: 1998, Page(s):502 - 515
    Cited by:  Papers (19)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (672 KB)

    The asymptotic multiuser efficiencies (AMEs) are derived for various classes of decision-directed multiuser detectors, including multistage detectors, and decision-feedback detectors. Novel classes of soft-decision multistage detectors are proposed and analyzed. Each class is specified in part by a soft-decision nonlinearity, such as a symmetric quantizer or a linear clipper. Closed-form expressio... View full abstract»

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  • The sample complexity of pattern classification with neural networks: the size of the weights is more important than the size of the network

    Publication Year: 1998, Page(s):525 - 536
    Cited by:  Papers (361)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (584 KB)

    Sample complexity results from computational learning theory, when applied to neural network learning for pattern classification problems, suggest that for good generalization performance the number of training examples should grow at least linearly with the number of adjustable parameters in the network. Results in this paper show that if a large neural network is used for a pattern classificatio... View full abstract»

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  • Critical distortion of Potts model

    Publication Year: 1998, Page(s):896 - 899
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (176 KB)

    The critical distortion dc of the Potts models on a number of lattices is shown to be related to the radius of convergence R of Mayer's series by dc=(q-1)R/(1+R). By using the matrix representation of Mayer's series, a recursive approach is applied to estimate R, and hence dc for Ising models for which q=2 View full abstract»

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  • Asymptotic eigenvalue distribution of block-Toeplitz matrices

    Publication Year: 1998, Page(s):858 - 861
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (152 KB)

    The need for approximating block-Toeplitz with Toeplitz block matrices by means of block-circulant with circulant block matrices with the objective of transforming an inherently ill-posed image deconvolution problem to a well-posed one motivated a surge of papers on the analysis of the quality as well as the speed of convergence of the algorithms that produce such approximants to serve as precondi... View full abstract»

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  • Redundancy of the Lempel-Ziv string matching code

    Publication Year: 1998, Page(s):787 - 791
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    For any given source output string from a unifilar, Markov source, we bound from above the amount by which the number of binary digits used by two variants of LZ'77 to encode the string exceeds its self-information as a function of its length and self-information View full abstract»

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  • Decompositions and extremal type II codes over Z4

    Publication Year: 1998, Page(s):800 - 809
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    In previous work by Huffman and by Yorgov (1983), a decomposition theory of self-dual linear codes C over a finite field Fq was given when C has a permutation automorphism of prime order r relatively prime to q. We extend these results to linear codes over the Galois ring Z4 and apply the theory to Z4-codes of length 24. In particular we obtain 42... View full abstract»

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  • Shannon capacity of M-ary redundant multitrack runlength limited codes

    Publication Year: 1998, Page(s):766 - 774
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (548 KB)

    We consider multiamplitude, multitrack runlength-limited (d, k) constrained channels with and without clock redundancy. We calculate the Shannon capacities of these channels and present some simple 100% efficient codes. To compute capacity a constraint graph equivalent to the usual runlength-limited constraint graph is used. The introduced graph model has the vertex labeling independent of number ... View full abstract»

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  • Achievable rates for Tomlinson-Harashima precoding

    Publication Year: 1998, Page(s):824 - 831
    Cited by:  Papers (64)  |  Patents (38)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    This article examines Tomlinson-Harashima precoding (1971, 1972) on discrete-time channels having intersymbol interference and additive white Gaussian noise. An exact expression for the maximum achievable information rate of zero-forcing (ZF) THP is derived as a function of the channel impulse response, the input power constraint, and the additive white Gaussian noise variance. Information rate bo... View full abstract»

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  • A trellis-based recursive maximum-likelihood decoding algorithm for binary linear block codes

    Publication Year: 1998, Page(s):714 - 729
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (720 KB)

    This paper presents an efficient trellis-based maximum-likelihood decoding algorithm for binary linear block codes. This algorithm is recursive in nature and is devised based on the structural properties and optimum sectionalization of a code trellis. The complexity of the proposed decoding algorithm is analyzed. Numerical results show that the proposed decoding algorithm significantly reduces the... View full abstract»

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  • Limits to consistent on-line forecasting for ergodic time series

    Publication Year: 1998, Page(s):886 - 892
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    This article concerns problems of time-series forecasting under the weakest of assumptions. Related results are surveyed and are points of departure for the developments here, some of which are new and others are new derivations of previous findings. The contributions in this study are all negative, showing that various plausible prediction problems are unsolvable, or in other cases, are not solva... 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