# IEEE Transactions on Information Theory

## Filter Results

Displaying Results 1 - 25 of 45
• ### Generalized Hamming weights of nonlinear codes and the relation to the Z4-linear representation

Publication Year: 1999, Page(s):713 - 720
Cited by:  Papers (1)
| | PDF (320 KB)

We give a new definition of generalized Hamming weights of nonlinear codes and a new interpretation connected with it. These generalized weights are determined by the entropy/length profile of the code. We show that this definition characterizes the performance of nonlinear codes on the wire-tap channel of type II. The new definition is invariant under translates of the code, it satisfies the prop... View full abstract»

• ### The second and third generalized Hamming weights of Hermitian codes

Publication Year: 1999, Page(s):709 - 712
Cited by:  Papers (12)
| | PDF (168 KB)

We determine the second and third generalized Hamming weights of all Hermitian codes View full abstract»

• ### Codes on Garcia-Stichtenoth curves with true distance greater than Feng-Rao distance

Publication Year: 1999, Page(s):706 - 709
Cited by:  Papers (6)
| | PDF (172 KB)

We give codes on all members after level 4 of the family of Garcia-Stichtenoth (see Invent. Math., vol.121, p.211-22, 1995) curves with the property dtrue>dFR. These codes also give an improvement on Tsfasman-Vladut-Zink bound View full abstract»

• ### Codes of lengths 120 and 136 meeting the Grey-Rankin bound and quasi-symmetric designs

Publication Year: 1999, Page(s):703 - 706
Cited by:  Papers (2)
| | PDF (188 KB)

In this correspondence, we give a characterization of certain quasi-cyclic self-complementary codes with parameters [120,9,56] and [136,9,64], some quasi-cyclic self-complementary codes are also constructed with parameters [496,11,240] and [528,11,256]. These codes are optimal in the sense that they meet the Grey-Rankin bound, new quasi-symmetric SDP (symmetric difference property) designs are con... View full abstract»

• ### Hadamard-based soft decoding for vector quantization over noisy channels

Publication Year: 1999, Page(s):515 - 532
Cited by:  Papers (40)
| | PDF (856 KB)

We present an estimator-based, or soft, vector quantizer decoder for communication over a noisy channel. The decoder is optimal according to the mean-square error criterion, and Hadamard-based in the sense that a Hadamard transform representation of the vector quantizer is utilized in the implementation of the decoder. An efficient algorithm for optimal decoding is derived. We furthermore investig... View full abstract»

• ### Efficient code constructions for certain two-dimensional constraints

Publication Year: 1999, Page(s):794 - 799
Cited by:  Papers (20)  |  Patents (2)
| | PDF (232 KB)

Efficient encoding algorithms are presented for two types of constraints on two-dimensional binary arrays. The first constraint considered is that of t-conservative arrays, where each row and each column has at least t transitions of the form 0'→1' or 1'→0.' The second constraint is that of two-dimensional DC-free arrays, where in each row and each column the number of `0's equals th... View full abstract»

• ### On a class of self-dual codes derived from quadratic residues

Publication Year: 1999, Page(s):701 - 702
Cited by:  Papers (6)
| | PDF (112 KB)

In 1976, Moore investigated a class of self-dual double-circulant codes based on primes of the form q=3 mod 8. This paper shows that the corresponding length 168 code contains a weight 28 codeword and thus is not extremal. This answers a long-standing question regarding this code. The next five codes in this class are also shown not to be extremal View full abstract»

• ### Unconditionally secure key agreement and the intrinsic conditional information

Publication Year: 1999, Page(s):499 - 514
Cited by:  Papers (106)  |  Patents (16)
| | PDF (784 KB)

This paper is concerned with secret-key agreement by public discussion. Assume that two parties Alice and Bob and an adversary Eve have access to independent realizations of random variables X, Y, and Z, respectively, with joint distribution PXYZ. The secret-key rate S(X;Y||Z) has been defined as the maximal rate at which Alice and Bob can generate a secret key by communication over an ... View full abstract»

• ### Binary sequences with two-level autocorrelation

Publication Year: 1999, Page(s):692 - 693
Cited by:  Papers (9)
| | PDF (104 KB)

We derive the values of the Fourier spectrum, a decomposition, and an achievable upper bound on the linear span, for binary sequences with two-level autocorrelation View full abstract»

• ### Randomly chosen index assignments are asymptotically bad for uniform sources

Publication Year: 1999, Page(s):788 - 794
Cited by:  Papers (11)  |  Patents (2)
| | PDF (308 KB)

It is known that among all redundancy-free codes (or index assignments), the natural binary code minimizes the mean-squared error (MSE) of the uniform source and uniform quantizer on a binary symmetric channel. We derive a code which maximizes the MSE and demonstrate that the code is linear and its distortion is asymptotically equivalent, as the block length grows, to the expected distortion of an... View full abstract»

• ### Coded diversity on block-fading channels

Publication Year: 1999, Page(s):771 - 781
Cited by:  Papers (154)  |  Patents (2)
| | PDF (460 KB)

This paper considers coded diversity schemes over block-fading Rician channels using random coding techniques. Two random coding upper bounds on the error probability of block codes are derived: a new bound and a simpler but looser bound assuming binary input distribution. Also, a new lower bound for any block code is derived using the strong converse to channel coding theorem. The lower bound sho... View full abstract»

• ### Cyclotomy and duadic codes of prime lengths

Publication Year: 1999, Page(s):453 - 466
Cited by:  Papers (15)
| | PDF (620 KB)

We present a cyclotomic approach to the construction of all binary duadic codes of prime lengths. We calculate the number of all binary duadic codes for a given prime length and that of all duadic codes that are not quadratic residue codes. We give necessary and sufficient conditions for p such that all binary duadic codes of length p are quadratic residue (QR) codes. We also show how to determine... View full abstract»

• ### Disjointness of random sequence sets with respect to distinct probability measures

Publication Year: 1999, Page(s):756 - 760
Cited by:  Papers (1)
| | PDF (224 KB)

It is shown that the set of deterministic random sequences (of symbols from a finite alphabet) with respect to a computable probability measure μ, in Martin-Lof's (1966) sense, and the set of deterministic random sequences with respect to another computable probability measure ν are disjoint if μ and ν are different and the measures are either i.i.d. or homogeneous finite-order irreduc... View full abstract»

• ### List decoding of algebraic-geometric codes

Publication Year: 1999, Page(s):432 - 437
Cited by:  Papers (30)  |  Patents (1)
| | PDF (316 KB)

We generalize Sudan's (see J. Compl., vol.13, p.180-93, 1997) results for Reed-Solomon codes to the class of algebraic-geometric codes, designing algorithms for list decoding of algebraic geometric codes which can decode beyond the conventional error-correction bound (d-1)/2, d being the minimum distance of the code. Our main algorithm is based on an interpolation scheme and factorization of polyn... View full abstract»

• ### All Reed-Muller codes are linearly representable over the ring of dual numbers over Z2

Publication Year: 1999, Page(s):700 - 701
Cited by:  Papers (4)
| | PDF (120 KB)

The statement given in the title is proved. Linear codes over chain rings (commutative and noncommutative) are a natural generalization of linear codes over finite fields and of linear codes over integer residue class rings of prime power order. In matters of linear representability there is no obvious reason why we should prefer one chain ring to the other. Yet, apart from Z4, there is... View full abstract»

• ### Correlation attacks on up/down and stop/go cascades

Publication Year: 1999, Page(s):486 - 498
Cited by:  Papers (2)
| | PDF (548 KB)

A probabilistic analysis is conducted to determine conditional and unconditional correlation weaknesses of cascades of up/down clocked shift registers. Similar results are also obtained for cascades of stop/go clocked shift registers. It is theoretically explained how to use the derived properties for fast correlation attacks, whose objective is to recover the linear feedback shift-register initia... View full abstract»

• ### Arbitrarily varying multiple-access channels. I. Ericson's symmetrizability is adequate, Gubner's conjecture is true

Publication Year: 1999, Page(s):742 - 749
Cited by:  Papers (19)
| | PDF (436 KB)

In 1981 Jahn used the elimination technique of the first author to determine the average errors capacity region of an arbitrarily varying multiple-access channel (AVMAC), when this region has a nonempty interior. Here we remove this restriction. In his thesis (1990), Gubner (1990) missed this result because he used the first author's first approach to the MAC, which is based on conditional decodin... View full abstract»

• ### Variable-rate trellis source encoding

Publication Year: 1999, Page(s):586 - 608
Cited by:  Papers (25)  |  Patents (23)
| | PDF (1424 KB)

The fixed slope lossy algorithm derived from the kth-order adaptive arithmetic codeword length function is extended to finite-state decoders or trellis-structured decoders. When this algorithm is used to encode a stationary, ergodic source with a continuous alphabet, the Lagrangian performance converges with probability one to a quantity computable as the infimum of an information-theoretic functi... View full abstract»

• ### Improved rates and asymptotic normality for nonparametric neural network estimators

Publication Year: 1999, Page(s):682 - 691
Cited by:  Papers (27)
| | PDF (580 KB)

We obtain an improved approximation rate (in Sobolev norm) of r -1/2-α(d+1)/ for a large class of single hidden layer feedforward artificial neural networks (ANN) with r hidden units and possibly nonsigmoid activation functions when the target function satisfies certain smoothness conditions. Here, d is the dimension of the domain of the target function, and α∈(0, 1) is... View full abstract»

• ### On the rectangularity of nonlinear block codes

Publication Year: 1999, Page(s):720 - 725
Cited by:  Papers (2)
| | PDF (228 KB)

We give simple sufficient conditions for a code to be rectangular and show that large families of well-known nonlinear codes are rectangular. These include Hadamard (1893), Levenshtein (1964), Delsarte-Goethals (1975), Kerdock (1972), and Nordstrom-Robinson (1967) codes. Being rectangular, each of these codes has a unique minimal trellis that can be used for soft-decision maximum-likelihood decodi... View full abstract»

• ### High-resolution source coding for non-difference distortion measures: the rate-distortion function

Publication Year: 1999, Page(s):533 - 547
Cited by:  Papers (15)
| | PDF (952 KB)

The problem of asymptotic (i,e., low-distortion) behavior of the rate-distortion function of a random vector is investigated for a class of non-difference distortion measures. The main result is an asymptotically tight expression which parallels the Shannon lower bound for difference distortion measures. For example, for an input-weighted squared error distortion measure d(x,y)=||W(x)(y-x)||2... View full abstract»

• ### New upper bounds on error exponents

Publication Year: 1999, Page(s):385 - 398
Cited by:  Papers (38)
| | PDF (688 KB)

We derive new upper bounds on the error exponents for the maximum-likelihood decoding and error detecting in the binary symmetric channels. This is an improvement on the best earlier known bounds by Shannon-Gallager-Berlekamp (1967) and McEliece-Omura (1977). For the probability of undetected error the new bounds are better than the bounds by Levenshtein (1978, 1989) and the bound by Abdel-Ghaffar... View full abstract»

• ### An improved upper bound of the rate of Euclidean superimposed codes

Publication Year: 1999, Page(s):799 - 802
Cited by:  Papers (7)
| | PDF (184 KB)

A family of n-dimensional unit norm vectors is an Euclidean superimposed code if the sums of any two distinct at most m-tuples of vectors are separated by a certain minimum Euclidean distance d. Ericson and Gyorfi (1988) proved that the rate of such a code is between (log m)/4m and (log m)/m for m large enough. In this paper-improving the above long-standing best upper bound for the rate-it is sho... View full abstract»

• ### Linear complexity of de Bruijn sequences-old and new results

Publication Year: 1999, Page(s):693 - 698
Cited by:  Papers (11)
| | PDF (308 KB)

The linear complexity of a de Bruijn sequence is the degree of the shortest linear recursion which generates the sequence. It is well known that the complexity of a binary de Bruijn sequence of length 2n is bounded below by 2n-1+n and above by 2n-1 for n⩾3. We briefly survey the known knowledge in this area. Some new results are also presented, in particular, ... View full abstract»

• ### Trellis-coded quantization for binary erasure channels

Publication Year: 1999, Page(s):781 - 787
Cited by:  Papers (1)
| | PDF (272 KB)

Trellis-coded quantizers (TCQ) are designed for the binary erasure channel (BEC) for memoryless sources. When the bit erasure rate is large, the channel-optimized TCQ can provide up to 1.4 dB improvement over TCQ designed for a lossless channel View full abstract»

## 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
Prakash Narayan

Department of Electrical and Computer Engineering