IEEE Transactions on Information Theory

A test sequence is called(s,t)-universal if it exercises every function depending on t or fewer inputs on a very large scale integration (VLSI) chip withsinputs. Randomized and deterministic procedures are deseribed for the design of(s,t)-universal sequences and for the signature analysis of the test outputs. View full abstract»

Thekinput and output digits of a rate(k/n)linear convolutional code over a finite field GF(q)are related to a finite set of integers by aq-ary expansion. The mean-square error criterion is used to simultaneously select the optimum encoder and decoder rules. This optimization is performed over all one-to-one generalized encoding rules and all decoding fun... View full abstract»

Many forms of digital memory have been developed for the permanent storage of information. These include keypunch cards, paper tapes, PROMs, photographic film and, more recently, digital optical disks. All these "write-once" memories have the property that once a "one" is written in a particular cell, this cell becomes irreversibly set at one. Thus, the ability to rewrite information in the memory... View full abstract»

Multitype branching processes have been employed to determine the stack algorithm computational distribution for one subtree. These results are extended here to the distribution of the number of computations in any finite number of subtrees. Starting from the computational distribution forK-1subsequent subtrees, a recurrent equation for the distribution forKsubsequent subtree... View full abstract»

For arbitrary number systems we present a new check-digit method that detects all single-digit errors and all transpositions of adjacent digits using a single check digit from the given number system. In previous methods at least one type of transpositional error had to remain undetected. The key to this method lies in using the dihedral groups together with appropriate transformations in the impo... View full abstract»

A lower bound is proposed for the mean-squared error of ann-dimensional vector quantizer with a large number of output points. View full abstract»

Random codes for the arbitrarily varying channel are investigated. The code ensemble is restricted to increase only exponentially with codeword length; a quantity called key rate is used as a measure of the rate of increase. The reliability function for such codes is related to the reliability function for codes with unlimited key rate. Explicit results are obtained in some examples of practical i... View full abstract»

The construction of a class of binary linear codes for masking computer memory defects is presented. These codes are capable of masking three or fewer defects and correcting multiple random errors. View full abstract»

A stochastic model-based approach is presented for estimation of the two-dimensional maximum entropy power spectrum (MEPS) from given finite uniform array data. The method consists of fitting an appropriate two-dimensional noncausal Gaussian-Markov random field (GMRF) model to the given data using the maximum likelihood (ML) technique for parameter estimation. The nonlinear criterion function used... View full abstract»

Some schemes for detecting moving point targets against structured backgrounds from observations on the output of an imaging system are investigated. When the velocity of the target and the background image are considered as known, it is shown that the uniformly most powerful detector, invariant with respect to image intensity variations, consists of specific spatial-temporal differencing schemes.... View full abstract»

It is shown that the multiplier, the increment, and the seed value of a linear congruential random number generator on a binary computer can be deduced from the leading bits of the "random" numbers that are generated. View full abstract»

An explicit construction is presented of uniquely decodable code pairs for the two-access binary erasure channel. Through a computer search we found many code pairs coming from this construction with a rate pair above the nonconstructive lower bound known in the literature. Also presented is a simple uniquely decodable code pair, with a high rate pair, found by a different method. View full abstract»

The performance of chain codes for line drawings in the framework of source coding with a fidelity criterion is investigated. A formal characterization is given for a broad class of chain codes that includes the generalized chain codes of Freeman and the convex quantizers of Koplowitz. Measures of distortion (fidelity) and rate (efficiency) are introduced. The distortion and rate are calculated fo... View full abstract»

This work analyzes the detection performance of autocoherence (i.e., the magnitude-squared complex autocorrelation coefficient estimate) as a nonparametric detector of narrowband signals in broadband noise. The distribution theory of this statistic is derived along with approximations that permit easy analysis of the detection performance. It is shown in particular case studies that only 1 to 2.6 ... View full abstract»