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Wolf, J. K.

Publications and source records attributed to Wolf, J. K..

5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Algebraic decoding of block codes over a q-ary input, Q-ary output channel, Q greater than q.

Decoding algorithms designed for one output alphabet are shown to be effectively usable for channels with a different output alphabet. The described technique that makes this possible can be used in conjunction with an arbitrary distance measure between input and output vectors. Thus, Hamming distance, Lee distance, or a burst distance can be assumed. Examples are presented for each of these distances.

Wainberg, S.↗
NASA NTRS1972

Burst decoding of binary block codes on Q-ary output channels.

The burst-b distance between two binary vectors is defined and shown to be a metric. This definition is applied to a binary-input, Q-ary output channel where errors occur in bursts. A decoding algorithm is presented for such a channel that is an extension of Weldon's (1971) weighted erasure decoding. Examples are presented illustrating the techniques.

Wainberg, S.↗
NASA NTRS1972

Permutation codes for sources.

Source encoding techniques based on permutation codes are investigated. For a broad class of distortion measures it is shown that optimum encoding of a source permutation code is easy to instrument even for very long block lengths. Also, the nonparametric nature of permutation encoding is well suited to situations involving unknown source statistics. For the squared-error distortion measure a procedure for generating good permutation codes of a given rate and block length is described. The performance of such codes for a memoryless Gaussian source is compared both with the rate-distortion function bound and with the performance of various quantization schemes. The comparison reveals that permutation codes are asymptotically ideal for small rates and perform as well as the best entropy-coded quantizers presently known for intermediate rates. They can be made to compare favorably at high rates, too, provided the coding delay associated with extremely long block lengths is tolerable.

Berger, T.↗