IEEE Transactions on Information Theory

Volume 41 Issue 3 • May 1995

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Displaying Results 1 - 25 of 35
  • De-noising by soft-thresholding

    Publication Year: 1995, Page(s):613 - 627
    Cited by:  Papers (4520)  |  Patents (73)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1377 KB)

    Donoho and Johnstone (1994) proposed a method for reconstructing an unknown function f on [0,1] from noisy data d/sub i/=f(t/sub i/)+/spl sigma/z/sub i/, i=0, ..., n-1,t/sub i/=i/n, where the z/sub i/ are independent and identically distributed standard Gaussian random variables. The reconstruction f/spl circ/*/sub n/ is defined in the wavelet domain by translating all the empirical wavelet coeffi... View full abstract»

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  • On the continuous wavelet transform of second-order random processes

    Publication Year: 1995, Page(s):628 - 642
    Cited by:  Papers (26)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1310 KB)

    Some second-order properties of random processes such as periodic correlation, stationarity, harmonizability, self-similarity, are characterized via corresponding properties of their wavelet transform: any one of these properties of the wavelet transform characterizes the corresponding property of the increments of the random process, of order equal to the order of regularity of the analyzing wave... View full abstract»

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  • A universal finite memory source

    Publication Year: 1995, Page(s):643 - 652
    Cited by:  Papers (131)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1025 KB)

    An irreducible parameterization for a finite memory source is constructed in the form of a tree machine. A universal information source for the set of finite memory sources is constructed by a predictive modification of an earlier studied algorithm-Context. It is shown that this universal source incorporates any minimal data-generating tree machine in an asymptotically optimal manner in the follow... View full abstract»

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  • The context-tree weighting method: basic properties

    Publication Year: 1995, Page(s):653 - 664
    Cited by:  Papers (368)  |  Patents (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (982 KB)

    Describes a sequential universal data compression procedure for binary tree sources that performs the "double mixture." Using a context tree, this method weights in an efficient recursive way the coding distributions corresponding to all bounded memory tree sources, and achieves a desirable coding distribution for tree sources with an unknown model and unknown parameters. Computational and storage... View full abstract»

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  • Fixed-rate universal lossy source coding and rates of convergence for memoryless sources

    Publication Year: 1995, Page(s):665 - 676
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1024 KB)

    A fixed-rate universal lossy coding scheme is introduced for independent and identically distributed (i.i.d.) sources. It is shown for finite alphabet sources and arbitrary single letter distortion measures that as the sample size n grows the expected distortion obtained using this universal scheme converges to Shannon's distortion rate function D(R) at a rate O(log n/n). The scheme can be extende... View full abstract»

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  • Nonparametric estimation via empirical risk minimization

    Publication Year: 1995, Page(s):677 - 687
    Cited by:  Papers (79)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1034 KB)

    A general notion of universal consistency of nonparametric estimators is introduced that applies to regression estimation, conditional median estimation, curve fitting, pattern recognition, and learning concepts. General methods for proving consistency of estimators based on minimizing the empirical error are shown. In particular, distribution-free almost sure consistency of neural network estimat... View full abstract»

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  • Optimal simultaneous detection and estimation under a false alarm constraint

    Publication Year: 1995, Page(s):688 - 703
    Cited by:  Papers (57)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1410 KB)

    This paper addresses the problem of finite sample simultaneous detection and estimation which arises when estimation of signal parameters is desired but signal presence is uncertain. In general, a joint detection and estimation algorithm cannot simultaneously achieve optimal detection and optimal estimation performance. We develop a multihypothesis testing framework for studying the tradeoffs betw... View full abstract»

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  • Optimum soft-output detection for channels with intersymbol interference

    Publication Year: 1995, Page(s):704 - 713
    Cited by:  Papers (114)  |  Patents (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (958 KB)

    In contrast to the conventional Viterbi algorithm (VA) which generates hard-outputs, an optimum soft-output algorithm (OSA) is derived under the constraint of fixed decision delay for detection of M-ary digital signals in the presence of intersymbol interference and additive white Gaussian noise. The OSA, a new type of the conventional symbol-by-symbol maximum a posteriori probability algorithm, r... View full abstract»

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  • A strong version of the redundancy-capacity theorem of universal coding

    Publication Year: 1995, Page(s):714 - 722
    Cited by:  Papers (57)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (948 KB)

    The capacity of the channel induced by a given class of sources is well known to be an attainable lower bound on the redundancy of universal codes with respect to this class, both in the minimax sense and in the Bayesian (maximin) sense. We show that this capacity is essentially a lower bound also in a stronger sense, that is, for "most" sources in the class. This result extends Rissanen's (1984, ... View full abstract»

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  • Improved redundancy of a version of the Lempel-Ziv algorithm

    Publication Year: 1995, Page(s):723 - 731
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (561 KB)

    The Lempel-Ziv data compression algorithm has the property that for finite-memory sources the redundancy /spl rho//sub n/ (defined as the difference between the average code rate and the entropy when the memory size is n) is O (log log n/log n). We suggest a new version of the algorithm with redundancy /spl rho//sub n/=O (1/log n).<<ETX>> View full abstract»

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  • Covering properties of convolutional codes and associated lattices

    Publication Year: 1995, Page(s):732 - 746
    Cited by:  Papers (17)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1314 KB)

    The paper describes Markov methods for analyzing the expected and worst case performance of sequence-based methods of quantization. We suppose that the quantization algorithm is dynamic programming, where the current step depends on a vector of path metrics, which we call a metric function. Our principal objective is a concise representation of these metric functions and the possible trajectories ... View full abstract»

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  • Coding for two-head recording systems

    Publication Year: 1995, Page(s):747 - 755
    Cited by:  Papers (13)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (766 KB)

    A reduction in the track width in disc-recording systems results in a desirable increase in areal density, but also in the undesirable appearance of inter-track interference (ITI) and loss of signal-to-noise ratio (SNR). One way the effects of ITI may be alleviated is through the use of multiple-head systems simultaneously writing and reading a number of adjacent tracks. In this paper we investiga... View full abstract»

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  • State diagram connectivity and its effects on the decoding of shift-register-based codes

    Publication Year: 1995, Page(s):756 - 761
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (703 KB)

    Coding performance is limited not only by Shannon's (1950) bounds but also by the complexity of decoders. Decoder complexity is in turn governed by the need for the different pieces of the machine to communicate with one another. This paper calculates lower limits on the intra-system information flow for the Viterbi decoding of shift-register-based codes, e.g., convolutional codes. These limits pr... View full abstract»

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  • Shadow codes and weight enumerators

    Publication Year: 1995, Page(s):762 - 768
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (586 KB)

    The technique of using shadow codes to build larger self-dual codes is extended to codes over arbitrary fields. It is shown how to build the codes and how to determine the new weight enumerator as well. For codes over fields equipped with a square root of -1 and not of characteristic 2, a self-dual code of length n+2 can be built from a self-dual code of length n; for codes over a field without a ... View full abstract»

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  • New models and algorithms for future networks

    Publication Year: 1995, Page(s):769 - 780
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1439 KB)

    In future networks, transmission and switching capacity will dominate processing capacity. The authors investigate the way in which distributed algorithms should be changed in order to operate efficiently in this new environment. They introduce a class of new models for distributed algorithms which make explicit the difference between switching and processing. Based on these new models they define... View full abstract»

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  • Subgroup subcodes

    Publication Year: 1995, Page(s):781 - 785
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (482 KB)

    Subgroup subcodes and their duals which can be considered as an extension of subfield subcodes and trace codes are defined. Some of their basic properties are investigated. Examples of good subgroup subcodes are included.<<ETX>> View full abstract»

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  • On spectra of BCH codes

    Publication Year: 1995, Page(s):786 - 788
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (251 KB)

    Derives an estimate for the error term in the binomial approximation of spectra of BCH codes. This estimate asymptotically improves on the bounds by Sidelnikov (1971), Kasami et al. (1985), and Sole (1990).<<ETX>> View full abstract»

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  • On primitive BCH codes with unequal error protection capabilities

    Publication Year: 1995, Page(s):788 - 790
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (321 KB)

    Presents a class of binary primitive BCH codes that have unequal-error-protection (UEP) capabilities. The authors use a previous result on the span of their minimum weight vectors to show that binary primitive BCH codes, containing second-order punctured Reed-Muller (RM) codes of the same minimum distance, are binary-cyclic UEP codes. The values of the error correction levels for this class of bin... View full abstract»

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  • Constructing SCN bases in characteristic 2

    Publication Year: 1995, Page(s):790 - 794
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    A simple deterministic algorithm to construct a normal basis of GF(q/sup n/) over GF(q) (q=p/sup r/, p prime) is given. When p=2, the authors deduce a (self complementary normal-SCN) basis of GF(q/sup n/) over GF(q) for n odd, or n=2t, t odd. In characteristic 2 these cases are known to be the only possible ones for which there exists an SCN basis.<<ETX>> View full abstract»

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  • Linear codes for the sum mod-2 multiple-access channel with restricted access

    Publication Year: 1995, Page(s):794 - 799
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (581 KB)

    Transmission of information through a multiple-access-modulo-2 adder channel is addressed for the situation that out of a fixed family of N potential users at most some m, m<N are active simultaneously. The authors assign codes to the N users in a way that the receiver is able to correct any t or less errors and separate the s/spl les/m messages without a priori knowledge of the subset of activ... View full abstract»

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  • On the second generalized Hamming weight of the dual code of a double-error-correcting binary BCH code

    Publication Year: 1995, Page(s):805 - 808
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (341 KB)

    The generalized Hamming weight of a linear code is a new notion of higher dimensional Hamming weights. Let C be an [n,k] linear code and D be a subcode. The support of D is the cardinality of the set of not-always-zero bit positions of D. The rth generalized Hamming weight of C, denoted by d/sub r/(C), is defined as the minimum support of an r-dimensional subcode of C. It was shown by Wei (1991) t... View full abstract»

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  • Four nonexistence results for ternary linear codes

    Publication Year: 1995, Page(s):800 - 805
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (572 KB)

    It is proved that ternary codes with parameters [15,8,6], [15,9,5], [16,6,8], and [16,7,7] do not exist. This result solves the problem of finding optimal ternary linear codes of length at most 21. A table is given, showing the exact value of d/sub 3/(n,k) for n/spl les/21 with the earliest references.<<ETX>> View full abstract»

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  • Runlength-limited codes for single error detection in the magnetic recording channel

    Publication Year: 1995, Page(s):809 - 815
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (593 KB)

    An arithmetic function that assigns the value 0, 1, or 2 to each binary sequence is introduced. The authors call this function the error-check value. Two sequences that differ by a single symmetric error or a single shift error are shown to have different error-check values. Runlength-limited codes for detecting single-errors are designed by taking a set of the constrained sequences such that each... View full abstract»

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  • Algebraic construction of cyclic codes over Z/sub 8/ with a good Euclidean minimum distance

    Publication Year: 1995, Page(s):815 - 818
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (403 KB)

    Let S(8) denote the set of the eight admissible signals of an 8PSK communication system. The alphabet S(8) is endowed with the structure of Z/sub 8/, the set of integers taken modulo 8, and codes are defined to be Z/sub 8/-submodules of Z/sub 8//sup n/. Three cyclic codes over Z/sub 8/ are then constructed. Their length is equal to 6, 8, and 7, and they, respectively, contain 64, 64, and 512 codew... View full abstract»

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  • Error-locator ideals for algebraic-geometric codes

    Publication Year: 1995, Page(s):819 - 824
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (558 KB)

    The error locations for an algebraic-geometric code C*(D,mP) are exactly the common zeros (that is, a projective variety V(I)) of a set (ideal) I of error-locator functions. The paper gives a one-dimensional Berlekamp-Massey version of the Feng-Rao (1993) algorithm for decoding algebraic-geometric codes C*(D,mP). This produces a generating set for I (as an ideal) of size at most /spl rho/ (the sma... 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
Alexander Barg

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

email: abarg-ittrans@ece.umd.edu