IEEE Transactions on Information Theory

Volume 38 Issue 6 • Nov. 1992

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Displaying Results 1 - 25 of 27
  • Lower bounds on the capacities of binary and ternary networks storing sparse random vectors

    Publication Year: 1992, Page(s):1633 - 1647
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1104 KB)

    It is shown that the memory capacity of networks of binary neurons storing, by the Hebbian rule, sparse random vectors over the field (0, 1)/sup N/ is at least c(N/p log N), where c is a positive scalar involving input error probabilities probability of an element being nonzero. A similar bound is derived for networks of ternary neurons, storing sparse vectors over (-1,0,1)/sup N/. These results, ... View full abstract»

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  • Linear inequalities for covering codes. II. Triple covering inequalities

    Publication Year: 1992, Page(s):1648 - 1662
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1058 KB)

    For Pt.I, see ibid., vol.37, no.3, p.573-82 (May 1991). The linear inequality method for covering codes is generalized. This method reduces the study of covering codes to the study of some local covering problems. One of these problems, the 1-3 covering system, is formulated and studied in detail. The results for this local covering problem lead to new linear inequalities satisfied by covering cod... View full abstract»

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  • Decoding geometric Goppa codes using an extra place

    Publication Year: 1992, Page(s):1663 - 1676
    Cited by:  Papers (28)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1150 KB)

    Decoding geometric Goppa codes can be reduced to solving the key congruence of a received word in an affine ring. If the codelength is smaller than the number of rational points on the curve, then this method can correct up to 1.2 (d*-L)/2-s errors, where d* is the designed minimum distance of the code and s is the Clifford defect. The affine ring with respect to a place P is the set of all ration... View full abstract»

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  • Performance of binary block codes at low signal-to-noise ratios

    Publication Year: 1992, Page(s):1677 - 1687
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (911 KB)

    The performance of general binary block codes on an unquantized additive white Gaussian noise (AWGN) channel at low signal-to-noise ratios is considered. Expressions are derived for both the block error and the bit error probabilities near the point where the bit signal-to-noise ratio is zero. These expressions depend on the global geometric structure of the code, although the minimum distance sti... View full abstract»

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  • Gaps in the binary weight distributions of Reed-Solomon codes

    Publication Year: 1992, Page(s):1688 - 1697
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1133 KB)

    When a Reed-Solomon code is expanded to form a binary code, certain combinations of the spectrum of the Reed-Solomon code and the basis used for the expansion result in large gaps in the weight distribution of the binary code. It is shown that the size of these gaps can be bounded by computing the sums of various powers of the basis elements and applying a theorem normally used for cyclic codes. T... View full abstract»

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  • On the reconstruction aspects of moment descriptors

    Publication Year: 1992, Page(s):1698 - 1708
    Cited by:  Papers (59)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (905 KB)

    The problem of reconstruction of an image from discrete and noisy data by the method of moments is examined. The set of orthogonal moments based on Legendre polynomials is employed. A general class of signal-dependent noise models is taken into account. An asymptotic expansion for the global reconstruction error is established. This reveals mutual relationships between a number of moments, the ima... View full abstract»

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  • Lower and upper bounds on the minimum mean-square error in composite source signal estimation

    Publication Year: 1992, Page(s):1709 - 1724
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1316 KB)

    The performance of a minimum mean-square error (MMSE) estimator for the output signal from a composite source model (CSM), which has been degraded by statistically independent additive noise, is analyzed for a wide class of discrete-time and continuous-time models. In both cases, the MMSE is decomposed into the MMSE of the estimator, which is informed of the exact states of the signal and noise, a... View full abstract»

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  • Arbitrarily varying channels with general alphabets and states

    Publication Year: 1992, Page(s):1725 - 1742
    Cited by:  Papers (33)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1713 KB)

    Previous results of Csiszar and Narayan (1988, 1989, 1991) on the capacity of discrete arbitrarily varying channels with input and state constraints are extended to the case of arbitrary alphabets and state sets. For channels with scalar or vector inputs and additive interference consisting of a deterministic part and noise, both arbitrarily varying subject to power constraints, the capacity for d... View full abstract»

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  • Performance of a spread spectrum packet radio network link in a Poisson field of interferers

    Publication Year: 1992, Page(s):1743 - 1754
    Cited by:  Papers (153)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1163 KB)

    Results on the modeling of interference in a radio communication network and performance measures for the link as a function of distance are presented. It is assumed that a transmitter-receiver pair in a radio network is affected by a set of interferers, using the same modulation and power, whose positions are modeled as a Poisson field in the plane. Assuming a 1/r/sup gamma / propagation power lo... View full abstract»

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  • Image coding by adaptive tree-structured segmentation

    Publication Year: 1992, Page(s):1755 - 1767
    Cited by:  Papers (37)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1548 KB)

    A new algorithmic approach to segmentation-based image coding is proposed. A good compromise is achieved between segmentation by quadtree-based decomposition and by free region-growing in terms of time complexity and scene adaptability. Encoding is to recursively partition an image into convex n-gons, 3<or=n<or=8, until the pixels in the current n-gon satisfy a uniformity criterion. The recu... View full abstract»

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  • AR( infinity ) estimation and nonparametric stochastic complexity

    Publication Year: 1992, Page(s):1768 - 1778
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (857 KB)

    Let H* be the transfer function of a linear stochastic system such that H* and its inverse are in H/sup infinity /(D). Writing the system as an AR( infinity ) system, the best AR (k) approximation of the system is estimated using the method of least squares. A useful representation theorem for the parameter estimation error is presented. The effect of undermodeling and parameter uncertainty (due t... View full abstract»

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  • On tests for normality

    Publication Year: 1992, Page(s):1779 - 1787
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (678 KB)

    The problem of deciding whether a sample of a random field was generated by a Gaussian distribution is considered. Based on extensions of large deviation estimates due to M.D. Donsker and S.R.S. Varadhan (1985), a test that is optimal in a generalized Neyman-Pearson sense is proposed. This test turns out to depend on properties of the entropy of Gaussian processes and does not depend on cumulant c... View full abstract»

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  • Necessary and sufficient condition for capacity of the discrete time Gaussian channel to be increased by feedback

    Publication Year: 1992, Page(s):1788 - 1791
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    The problem of whether the capacity of a discrete-time Gaussian channel is increased by feedback or not is considered. It is well known that the capacity of a white Gaussian channel under an average power constraint is not changed by feedback. The necessary condition under which the capacity of a nonwhite Gaussian channel with blockwise white noise is increased by feedback is given.<<ETX>... View full abstract»

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  • Upper bounds for small trellis codes

    Publication Year: 1992, Page(s):1791 - 1795
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (488 KB)

    An upper bound on the minimum squared distance of trellis codes by packing Voronoi cells is derived and compared with previously known bounds. The authors focus on codes with small memory for modulation formats such as pulse amplitude modulation (PAM), m-ary quadrature amplitude modulation (QAM), and m-ary phase shift keying (PSK). The bound is tight to search results for coset codes with a small ... View full abstract»

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  • New minimum distance bounds for certain binary linear codes

    Publication Year: 1992, Page(s):1795 - 1796
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB)

    Let an (n, k, d)-code denote a binary linear code of length n, dimension k, and minimum distance at least d. Define d(n, k) as the maximum value of d for which there exists a binary linear (n, k, d)-code. T. Verhoeff (1989) has provided an updated table of bounds on d(n, k) for 1<or=k<or=n<or=127. The authors improve on some of the upper bounds given in that table by proving the nonexiste... View full abstract»

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  • On the Hamming distance properties of group codes

    Publication Year: 1992, Page(s):1797 - 1801
    Cited by:  Papers (31)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (621 KB)

    Under certain mild conditions, the minimum Hamming distance D of an (N, K, D) group code C over a non-abelian group G is bounded by D<or=N-2K+2 if K<or=N/2, and is equal to 1 if K>N/2. Consequently, there exists no (N, K, N-K+1) group code C over an non-abelian group G if 1<K<N. Moreover, any normal code C with a non-abelian output space has minimum Hamming distance equal to D=1. Th... View full abstract»

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  • Generalized key-equation of remainder decoding algorithm for Reed-Solomon codes

    Publication Year: 1992, Page(s):1801 - 1807
    Cited by:  Papers (18)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (580 KB)

    A key equation of the remainder decoding algorithm is presented. It is noted that the key equation presents a general relationship between the errors on the received codeword and the coefficients of the remainder polynomial. It is shown that several key equations proposed by L. Welch and E.R. Berlekamp (1983) and others can be derived from the proposed key equation. Useful properties of the key eq... View full abstract»

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  • A burst-error-correcting algorithm for Reed-Solomon codes

    Publication Year: 1992, Page(s):1807 - 1812
    Cited by:  Papers (27)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (552 KB)

    It is known that for a burst-error environment, the error-correcting capability of Reed-Solomon codes can be extended beyond the Singleton bound with a high degree of confidence. This is significant in that an (n, k) code with an arbitrarily small probability of a miscorrection can correct more than (n-k)/2 errors. A decoding algorithm for correcting a burst of length greater than (n-k)/2 is prese... View full abstract»

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  • Exact lower bounds on the codelength of three-step permutation-decodable cyclic codes

    Publication Year: 1992, Page(s):1812 - 1817
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (587 KB)

    The exact lower bounds on codelength n for three-step (T, U) permutation decodable binary cyclic codes of even-valued error number t (t>or=4) are presented. Since the derivation of these results involves only the error position, the results are applicable to cyclic codes over GF(2/sup m/).<<ETX>> View full abstract»

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  • Transform domain characterization of abelian codes

    Publication Year: 1992, Page(s):1817 - 1821
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (504 KB)

    Abelian codes constitute a class of codes that includes cyclic codes as a special case. It is shown that the general class of abelian codes can be characterized in the transform domain using the discrete Fourier transform (DFT) over finite fields with the appropriate mixed radix number system as the indexing scheme for DFT coefficients. A simple transform domain description for dual codes of abeli... View full abstract»

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  • Weighted Reed-Muller codes and algebraic-geometric codes

    Publication Year: 1992, Page(s):1821 - 1826
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (577 KB)

    A generalization of the Reed-Muller codes, the weighted Reed-Muller codes, is presented. The code parameters are estimated and the duals are shown also to be weighted Reed-Muller codes. It is shown how the minimum distance of certain algebraic-geometric codes in many cases can be determined exactly or an upper bound can be found, using subcodes which are weighted Reed-Muller codes.<<ETX>&... View full abstract»

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  • Permutation decoding of abelian codes

    Publication Year: 1992, Page(s):1826 - 1829
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (387 KB)

    A permutation decoding procedure for abelian codes is introduced by using the Groebner bases theory. This method is valid for decoding all the binary abelian codes. Some examples are given to show how powerful this method can be.<<ETX>> View full abstract»

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  • Existence of some extremal self-dual codes

    Publication Year: 1992, Page(s):1829 - 1833
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (467 KB)

    Two new singly-even extremal, self-dual codes are constructed: a (52,26,10) code and a (54,27,10) code.<<ETX>> View full abstract»

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  • Sequential decoding of low-density parity-check codes by adaptive reordering of parity checks

    Publication Year: 1992, Page(s):1833 - 1839
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (827 KB)

    Decoding algorithms in which unpruned codeword trees are generated from an ordered list of parity checks are investigated. The order is computed from the received message, and low-density parity-check codes are used to help control the growth of the tree. Simulation results are given for the binary erasure channel. They suggest that for the small erasure probability, the method is computationally ... View full abstract»

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  • The Lempel-Ziv algorithm and message complexity

    Publication Year: 1992, Page(s):1839 - 1842
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (465 KB)

    Data compression has been suggested as a nonparametric way of discriminating between message sources. Compressions obtained from a Lempel-Ziv algorithm for relatively short messages, such as those encountered in practice, are examined. The intuitive notion of message complexity has less connection with compression than one might expect from known asymptotic results about infinite messages. Neverth... 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