Annals of Faculty of Computer and Information Sciences, Hosei University
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HOME >> No.3 CONTENTS >> Toshihisa NISHIJIMA
Professor
Toshihisa NISHIJIMA
Publications(January 2002 - December 2002)
  1. T. Nishijima, "An Upper Bound on the Average Probability of an Undetected Error for the Ensemble of Binary Expansions of Generalized Reed-Solomon Codes," IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Vol. J85-A No. 1, pp. 137-140, January 2002.
    Abstract - We derive an upper bound on the average probability of an undetected error for the ensemble of binary expansions of generalized Reed-Solomon codes and, from this bound, conclude that the ensemble satisfies, in average, the Varshamov - Gilbert bound as well as the expurgated bound asymptotically for large block lengths.
  2. T. Nishijima, "On the Probability of an Undetected Error for Binary Expansions of Concatenated Codes with Generalized Reed-Solomon Outer Codes," IEICE Technical Report, IT-2002-1, pp.1-6, May 2002.
    Abstract - Concatenated codes given by G. D. Forney, Jr. are very important codes from practical and theoretical viewpoint. It can be shown that binary concatenated codes exist in this class which asymptotically meet the Varshamov - Gilbert bound. The constructive concatenated codes are the first asymptotically good codes. However the probability of an undetected error for binary expansion of concatenated codes is not discussed in the literature from both practical and theoretical viewpoints. As the first step, by utilizing the characteristic structure of concatenated codes, an approximately good computation method of the probability of an undetected error without knowing weight distributions of concatenated codes is proposed in this paper. Since the computational complexity of the method is at the most O(n), it is an efficient method when investigating the capability of error detection for a code from practical and theoretical viewpoint. By comparing exact values with approximate value in some examples of the codes, which are small enough for their weight distributions to be found by computer search, we show the efficiency of the approximate values by the proposed method. Their values also is compared with a upper bound on the average probability of an undetected error for the ensemble of those codes.

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