Jen-Chun Chang

Distance-preserving mappings from binary vectors to permutations

Mappings of the set of binary vectors of a fixed length to the set of permutations of the same length are useful for the construction of permutation codes. In this article, several explicit constructions of such mappings preserving or increasing the Hamming distance are given. Some applications are given to illustrate the usefulness of the construction. In particular, a new lower bound on the maximal size of permutation arrays (PAs) is given.

Distance-increasing mappings from binary vectors to permutations

In this correspondence, for any k ges 2, we first propose two constructions of (n,k) distance-increasing mappings (DIMs) from the set of binary vectors of length n to the set of permutations of the same length that strictly increase the Hamming distance by at least k except when it is obviously not possible. Next, we prove that for any k ges 2, there is a smallest positive integer nk such that an (n,k) DIM can be constructed for any n ges nk. An explicit upper bound on nk is also given

A fast reliability-algorithm for the circular consecutive-weighted-k-out-of-n:F system

An O(T n) algorithm is presented for the circular consecutive-weighted-k-out-of-n:F system, where T/spl les/min[n,[(k-/spl omega//sub max/)//spl omega//sub min/]+1]; /spl omega//sub max/, /spl omega//sub min/ are the maximum, minimum weights of all components. This algorithm is simpler and more efficient than the Wu and Chen O(min[n,k] n) algorithm. When all weights are unity, this algorithm is simpler than other O(k-n) published algorithms.

Distance-increasing mappings from binary vectors to permutations that increase hamming distances by at least two

In this correspondence, for any k ges 2, we first propose two constructions of (n,k) distance-increasing mappings (DIMs) from the set of binary vectors of length n to the set of permutations of the same length that strictly increase the Hamming distance by at least k except when it is obviously not possible. Next, we prove that for any k ges 2, there is a smallest positive integer nk such that an (n,k) DIM can be constructed for any n ges nk. An explicit upper bound on nk is also given

Comments on "Reliability and component importance of a consecutive-k-out-of-n system" by Zuo

Abstract Zuo claimed that the comparison of Birnbaum importance between two components for a consecutive- k -out-of- n : G system is the same as that for the F -system. We show that this is not the case and give a correct relation between the two systems.

Distance-Preserving and Distance-Increasing Mappings From Ternary Vectors to Permutations

Permutation arrays have found applications in powerline communication. One construction method for permutation arrays is to map good codes to permutations using a distance-preserving mappings (DPM). DPMs are mappings from the set of all q-ary vectors of a fixed length to the set of permutations of some fixed length (the same or longer) such that every two distinct vectors are mapped to permutations with the same or larger Hamming distance than that of the vectors. A DPM is called distance increasing (DIM) if the distances are strictly increased (except when the two vectors are equal). In this correspondence, we propose constructions of DPMs and DIMs from ternary vectors. The constructed DPMs and DIMs improve many lower bounds on the maximal size of permutation arrays.

A Hybrid RFID Protocol against Tracking Attacks

We study the problem how to construct an RFID mutual authentication protocol between tags and readers. Juels (in Journal on Selected Areas in Communications, 2006) proposed an open question which asks whether there exists a fully privacy-preserving RFID authentication protocol in which the time complexity of a successful authentication phase can be done in sub-linear time

New simple constructions of distance-increasing mappings from binary vectors to permutations

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Distance-increasing mappings from binary vectors to constant composition vectors

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A Minimal-Automaton-Based Algorithm for the Reliability of Con(d, k, n) Systems

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