IEEE Transactions on Information Theory

Volume 37 Issue 2 • March 1991

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Displaying Results 1 - 25 of 34
  • Coding capacity for a class of additive channels

    Publication Year: 1991, Page(s):233 - 243
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1164 KB)

    Coding capacity is considered for a class of additive dimension-limited channels. The channels may be with or without memory, stationary or nonstationary. The constraint is partially given in terms of an increasing family of finite-dimensional subspaces. A general expression for the capacity is obtained, which depends on the family of subspaces and the relation between the noise covariance and the... View full abstract»

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  • Information capacity of the Poisson channel

    Publication Year: 1991, Page(s):244 - 256
    Cited by:  Papers (49)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1054 KB)

    The information capacity of the Poisson channel with random or time-varying noise intensity is obtained for time-varying peak and average constraints on the encoder intensity. The channel model is specified, and some definitions from information theory are given. Causal feedback is shown not to increase the channel capacity for the case of nonrandom noise intensity. For random noise intensity, use... View full abstract»

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  • Strong converses in source coding relative to a fidelity criterion

    Publication Year: 1991, Page(s):257 - 262
    Cited by:  Papers (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (521 KB)

    Two strong converses are obtained for an abstract alphabet stationary ergodic source coded relative to an appropriate fidelity criterion. It is shown that given a distortion rate point (D,R) that lies below the rate distortion curve, (1) block codes that operate at rate level R must encode sample source blocks at a rate exceeding D with probability tending to one as the block length tends to infin... View full abstract»

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  • Sample converses in source coding theory

    Publication Year: 1991, Page(s):263 - 268
    Cited by:  Papers (44)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (577 KB)

    The rate and distortion performance of a sequence of codes along a sample sequence of symbols generated by a stationary ergodic information source are studied. Two results are obtained: (1) the source sample sequence is encoded by an arbitrary sequence of block codes which operate at a fixed rate level R, and a sample converse is obtained which states that, with probability one, the lower limit of... View full abstract»

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  • Successive refinement of information

    Publication Year: 1991, Page(s):269 - 275
    Cited by:  Papers (345)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (585 KB)

    The successive refinement of information consists of first approximating data using a few bits of information, then iteratively improving the approximation as more and more information is supplied. The goal is to achieve an optimal description at each stage. In general, an ongoing description which is rate-distortion optimal whenever it is interrupted is sought. It is shown that in order to achiev... View full abstract»

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  • An optimum strategy for detection in the presence of random transient disturbance and white Gaussian noise

    Publication Year: 1991, Page(s):276 - 284
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (749 KB)

    Detection of a deterministic signal is considered Because of the presence of the transient disturbance, the traditional totally probabilistic criteria are no longer appropriate, since they cannot be related to the physical reality, as in the case of stationary ergodic noise only. A mixed strategy is proposed for the detection where the disturbance is treated as a semideterministic object while whi... View full abstract»

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  • On universal hypotheses testing via large deviations

    Publication Year: 1991, Page(s):285 - 290
    Cited by:  Papers (32)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    A prototype problem in hypotheses testing is discussed. The problem of deciding whether an i.i.d. sequence of random variables has originated from a known source P/sub 1/ or an unknown source P/sub 2/ is considered. The exponential rate of decrease in type II probability of error under a constraint on the minimal rate of decrease in type I probability of error is chosen for a criterion of optimali... View full abstract»

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  • A parallel systems approach to universal receivers

    Publication Year: 1991, Page(s):291 - 306
    Cited by:  Papers (5)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1746 KB)

    The problem of communication over a channel with unknown characteristics is addressed. The true channel is from a known set of channels, but the transmitter and receiver do not know which of these channels is actually in effect. The goal of a universal receiver is to provide nearly optimal demodulation regardless of the channel that is actually in effect. A parallel receiver implementation is prop... View full abstract»

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  • Constrained solutions in importance via robust statistics

    Publication Year: 1991, Page(s):307 - 316
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (930 KB)

    The problem of estimating estimating expectations of functions of random vectors via simulation is investigated. Monte Carlo simulations, also known as simple averaging, have been used as a direct means of estimation. A technique known as importance sampling can be used to modify the simulation via weighted averaging in the hope that the estimate will converge more rapidly to the expected value th... View full abstract»

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  • Dense target signal processing

    Publication Year: 1991, Page(s):317 - 327
    Cited by:  Papers (53)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (972 KB)

    The problem of determining the density of targets at every range and velocity is addressed. These targets consist of a dense group of reflecting objects moving with different velocities and at different ranges. The problem of how to choose the outgoing signals and process the echoes of those signals from the targets to determine the density function is discussed. The problem is a classical inverse... View full abstract»

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  • Maximum-rank array codes and their application to crisscross error correction

    Publication Year: 1991, Page(s):328 - 336
    Cited by:  Papers (159)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (942 KB)

    A mu -(n*n,k) array code C over a field F is a k-dimensional linear space of n*n matrices over F such that every nonzero matrix in C has rank >or= mu . It is first shown that the dimension of such array codes must satisfy the Singleton-like bound k<or=n(n- mu +1). A family of so-called maximum-rank mu -(n*n,k=n (n- mu +1)) array codes is then constructed over every finite field F and for eve... View full abstract»

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  • On repeated-root cyclic codes

    Publication Year: 1991, Page(s):337 - 342
    Cited by:  Papers (84)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (554 KB)

    A parity-check matrix for a q-ary repeated-root cyclic code is derived using the Hasse derivative. Then the minimum distance of a q-ary repeated-root cyclic code is expressed in terms of the minimum distance of a certain simple-root cyclic code. With the help of this result, several binary repeated-root cyclic codes of lengths up to n=62 are shown to contain the largest known number of codewords f... View full abstract»

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  • Repeated-root cyclic codes

    Publication Year: 1991, Page(s):343 - 345
    Cited by:  Papers (78)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (322 KB)

    In the theory of cyclic codes, it is common practice to require that (n,q)=1, where n is the word length and F/sub q/ is the alphabet. It is shown that the even weight subcodes of the shortened binary Hamming codes form a sequence of repeated-root cyclic codes that are optimal. In nearly all other cases, one does not find good cyclic codes by dropping the usual restriction that n and q must be rel... View full abstract»

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  • The average binary weight-enumerator for a class of generalized Reed-Solomon codes

    Publication Year: 1991, Page(s):346 - 349
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (391 KB)

    An explicit weight-enumerator for the set of binary expansions of a class of generalized Reed-Solomon codes is derived. This enumerator is then used to show that most of these binary codes are asymptotically good, and to bound the rates of self-intersecting codes.<<ETX>> View full abstract»

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  • Binary (18,11)2 codes do not exist-Nor do (64,53)2 codes

    Publication Year: 1991, Page(s):349 - 351
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (329 KB)

    A binary, linear block code C with block length n and dimension n is commonly denoted by (n,k) or, if its minimum distance is d, by (n,k,d). The code's covering radius r(C) can be defined as the smallest number r such that any binary column vector of length (n-k) can be written as a sum of r or fewer columns of a parity-check matrix of C. An (n,k) code with covering radius r is denoted by (n,k)r. ... View full abstract»

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  • Modified bounds for covering codes

    Publication Year: 1991, Page(s):351 - 365
    Cited by:  Papers (42)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1295 KB)

    The covering radius of binary codes is studied. Bounds on K(n,R), the minimum cardinality of any binary code of length n and covering radius R, are found. Modifications of the van Wee lower bounds are proved for K(n,R), the minimal number of codewords in any binary code of length n and covering radius R. The first of the two van Wee bounds is based on studying the Hamming spheres of radius 1 cente... View full abstract»

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  • Classification of pseudo-cyclic MDS codes

    Publication Year: 1991, Page(s):365 - 370
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (574 KB)

    Linear codes are considered. A code is characterized by the length n, the dimension k, and the minimum distance d. An (n,k,d) code over the finite field GF(q) is said to be maximum distance separable (MDS) if d=n-k+1. A. Krishna and D.V. Sarwate (1990) investigated the existence of pseudo-cyclic MDS codes over GF(q) of length n, where n divides q-1 or q+1. It is shown that the pseudo-cyclic MDS co... View full abstract»

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  • Some new constant weight codes

    Publication Year: 1991, Page(s):370 - 371
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (207 KB)

    A(n,d, w) denotes the maximum cardinality of any binary code of length n, minimum distance d, and constant weight w. The results of a search for good constant weight codes using a combinatorial optimization algorithm are reported. A brief description of the algorithm is given. The problem of constructing a constant weight code of length n, minimum distance d, and weight w containing M codewords is... View full abstract»

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  • Bounds for abnormal binary codes with covering radius one

    Publication Year: 1991, Page(s):372 - 375
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (469 KB)

    The normality of binary codes is studied. The minimum cardinality of a binary code of length n with covering radius R is denoted by K(n,R). It is assumed that C is an (n,M)R code, that is, a binary code of length n with M codewords and covering radius R. It is shown that if C is an (n,M)1 code, then it is easy to find a normal (n,M)1 code by changing C in a suitable way, and that all the optimal (... View full abstract»

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  • Necessary conditions for good error detection

    Publication Year: 1991, Page(s):375 - 378
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (359 KB)

    The problem of determining the error detection capabilities of linear codes where the channel is a binary symmetric channel is addressed. Necessary conditions are given on the number of codewords in an (n,k) linear code and its dual for the probability of an undetected error to be upper bounded by 2/sup -(n-k)/.<<ETX>> View full abstract»

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  • Binary linear quasi-perfect codes are normal

    Publication Year: 1991, Page(s):378 - 379
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (206 KB)

    Whether quasi-perfect codes are normal is addressed. Let C be a code of length n, dimension k, covering radius R, and minimal distance d. It is proved that C is normal if d>or=2R-1. Hence all quasi-perfect codes are normal. Consequently, any (n,k)R binary linear code with minimal distance d>or=2R-1 is normal.<<ETX>> View full abstract»

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  • Performance analysis of disk allocation method using error-correcting codes

    Publication Year: 1991, Page(s):379 - 384
    Cited by:  Papers (5)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (441 KB)

    The problem of distributing a Cartesian product file on multiple disks to maximize the parallelism for partial match queries is addressed. C. Faloutsos et al. (1989) have proposed an allocation method for Cartesian product files on multiple disks by using linear error-correcting codes. The performance of the allocation method is analyzed. Some conditions under which the allocation method is strict... View full abstract»

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  • 2-D quasi m-arrays and Gold code arrays

    Publication Year: 1991, Page(s):385 - 388
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (410 KB)

    Two-dimensional quasi-maximal-area arrays (quasi-m-arrays) are proposed. These quasi-m-arrays are so named because their cyclic correlation properties are very close to those of the m-arrays. These arrays are generated by modulo-2 addition of maximal length sequences. The cyclic autocorrelation of any quasi-m-array is close to the delta-function. In addition, the cyclic cross-correlation is small ... View full abstract»

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  • On the maximum tolerable noise for reliable computation by formulas

    Publication Year: 1991, Page(s):388 - 391
    Cited by:  Papers (36)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (478 KB)

    It is shown that if formulas constructed from error-prone three-input gates are used to compute Boolean functions, then a per-gate failure probability of 1/6 or more cannot be tolerated. The result is shown to be tight if the per-gate failure probability is constant and precisely known.<<ETX>> View full abstract»

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  • On the number of points on shells for shifted Z/sup 4//sup n/ lattices

    Publication Year: 1991, Page(s):391 - 393
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (301 KB)

    A conjecture is proven on the number of points on shells for the shifted Z/sup 4 /and the shifted Z/sup 8/ lattices. Furthermore, the results are extended to any shifted Z/sup 4//sup n/ lattice (n=0, 1, . . .). These results provide an easy way to compute the number of points on shells for the type of lattices used in the design of multidimensional signal sets or in vector coding.<<ETX>&g... 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