In this paper we focus on the problem of compressed pattern matching for the text compression using antidictionaries, which is a new compression scheme proposed recently by Crochemore et al. (1998). We show an algorithm which preprocesses a pattern of length m and an antidictionary M in O(m 2 + kMk) time, and then scans a compressed text of length n in O(n+ r) time to nd all pattern occurrences...

In this paper we focus on the problem of compressed pattern matching for the text compression using antidictionaries, which is a new compression scheme proposed recently by Crochemore et al. (1998). We show an algorithm which preprocesses a pattern of length m and an antidictionary M in O(m 2 + kMk) time, and then scans a compressed text of length n in O(n+ r) time to nd all pattern occurrences...

Recently permutation multimedia ciphers were broken in a chosen-plaintext scenario. That attack models a very resourceful adversary which may not always be the case. To show insecurity of these ciphers, we present a cipher-text only attack on speech permutation ciphers. We show inherent redundancies of speech can pave the path for a successful cipher-text only attack. To that end, regularities ...

We show that Hopfield neural networks with synchronous dynamics and asymmetric weights admit stable orbits that form sequences of maximal length. For [Formula: see text] units, these sequences have length [Formula: see text]; that is, they cover the full state space. We present a mathematical proof that maximal-length orbits exist for all [Formula: see text], and we provide a method to construc...

We present a solution to the problem of regular expression searching on compressed text. The format we choose is the Ziv–Lempel family, specifically the LZ78 and LZW variants. Given a text of length u compressed into length n, and a pattern of length m, we report all the R occurrences of the pattern in the text in O(2m+mn+Rm logm) worst case time. On average this drops to O(m2 + (n+Rm) logm) or...

We present a solution to the problem of regular expression searching on compressed text. The format we choose is the Ziv-Lempel family, speciically the LZ78 and LZW variants. Given a text of length u compressed into length n, and a pattern of length m, we report all the R occurrences of the pattern in the text in O(2 m + mn + Rm log m) worst case time. On average this drops to O(m 2 + (n + R) l...

We present a solution to the problem of performing approximate pattern matching on compressed text. The format we choose is the Ziv-Lempel family, speciically the LZ78 and LZW variants. Given a text of length u compressed into length n, and a pattern of length m, we report all the R occurrences of the pattern in the text allowing up to k insertions, deletions and substitutions, in O(mkn + R) ti...

We compared entropy for texts written in natural languages (English, Spanish) and artificial languages (computer software) based on a simple expression for the entropy as a function of message length and specific word diversity. Code text written in artificial languages showed higher entropy than text of similar length expressed in natural languages. Spanish texts exhibit more symbolic diversit...

Given two strings, a pattern P of length m and a text T of length n over some alphabet Σ of size σ, we consider the exact string matching problem, i.e. we want to report all occurrences of P in T . The well-known Backward-Nondeterministic-DAWG-Matching (BNDM) algorithm is one of the most efficient algorithm for short to moderate length patterns. In this paper – as a prelude – we take the underl...

We propose an approach to develop a dictionary based reversible lossless text transformation, called LIPT (Length Index Preserving Transform), which can be applied to a source text to improve existing algorithm’s ability to compress. In LIPT, the length of the input word and the offset of the words in the dictionary are denoted with alphabets. Our encoding scheme makes use of recurrence of same...