Declustered data organizations have been proposed to achieve less-intrusive reconstruction of a failed disk’s contents. In previous work, Holland and Gibson identified six desirable properties for ideal layouts. Ideal layouts exist for a very limited family of configurations. The PRIME data layout deviates from the stated ideal only slightly and its run-time performance is very good for light w...

We look at some techniques for constructing permutation arrays using projections in finite projective spaces and the geometry of arcs in the finite projective plane. We say a permutation array PA(n, d) has length n and minimum distance d when it consists of a collection of permutations on n symbols that pairwise agree in at most n − d coordinate positions. Such arrays can also be viewed as non-...

The symmetric group Sn on n letters is a metric space with respect to the Hamming distance. The corresponding isometry group is well known to be isomorphic to the wreath product Sn oS2. A subset of Sn is called a permutation code or a permutation array, and the largest possible size of a permutation code with minimum Hamming distance d is denoted by M(n, d). Using exhaustive search by computer ...

Given a permutation of n elements, stored as an array, we address the problem of replacing the permutation by its kth power. We aim to perform this operation quickly using o(n) bits of extra storage. To this end, we first present an algorithm for inverting permutations that uses O(lg2 n) additional bits and runs in O(n lgn) worst case time. This result is then generalized to the situation in wh...

In this paper, by using the notion of fuzzy subsets, the concept of F-permutation is introduced. Then by applying this notion the concepts of presentation of an F-polygroup, graph of an F-permutation and F-permutation matrices are investigated.

By a quasi-permutation matrix we mean a square matrix over the complex field C with non-negative integral trace. Thus, every permutation matrix over C is a quasipermutation matrix. For a given finite group G, let p(G) denote the minimal degree of a faithful permutation representation of G (or of a faithful representation of G by permutation matrices), let q(G) denote the minimal degree of a fa...

We show how to off-line route any permutation of a n X n meshconnected processor array in 2.5n 3 steps with at most 6 packets per processor per time step and in 2.25n +3 steps with at most 8 packets per processor per time step.

In this paper, two array signal processing techniques are combined with independent component analysis (ICA) to enhance the performance of blind separation of acoustic signals in a reflective environment. The first technique is the subspace method which reduces the effect of room reflection when the system is used in a room. Room reflection is one of the biggest problems in blind source separat...

by a quasi-permutation matrix we mean a square matrix over the complex field c with non-negative integral trace. thus every permutation matrix over c is a quasipermutation matrix. for a given finite group g, let p(g) denote the minimal degree of a faithful permutation representation of g (or of a faithful representation of g by permutation matrices), let q(g) denote the minimal degree of a fait...