A construction of uniquely decodable codes for the two-user binary adder channel is presented. The rates of the codes obtained by this construction are greater than the rates guaranteed by the Coebergh van den Braak and van Tilborg construction and these codes can be used with simple encoding and decoding procedures.

This paper is the second part of a work dealing with two Schiitzenberger's conjectures on variable-length codes. It contains the detailed proofs of the characterization that we obtained for the degree and the decomposability of finite maximal codes over the alphabet {a, b} with at most 3 occurrences of the letter b in each word.

A classification of extremal double circulant self-dual codes of lengths up to 88 is known. We demonstrate that there is no extremal double circulant self-dual code of length 90. We give a classification of double circulant self-dual [90, 45, 14] codes. In addition, we demonstrate that every double circulant self-dual [90, 45, 14] code has no extremal selfdual neighbor of length 90. Finally, we...

An inherent problem with a Variable-Length Code (VLC) is that even a single bit error can cause a loss of synchronisation, and thus lead to error propagation. Codeword synchronisation has been extensively studied as a means to overcome this drawback and efficiently stop error propagation. In this paper, we first present the sufficient and necessary conditions for the existence of binary Huffman...

The K-length of a form f in K[x1, . . . , xn], K ⊂ C, is the smallest number of d-th powers of linear forms of which f is a K-linear combination. We present many results, old and new, about K-length, mainly in n = 2, and often about the length of the same form over different fields. For example, the K-length of 3x − 20xy + 10xy is three for K = Q( √ −1), four for K = Q( √ −2) and five for K = R.

This paper proposes an efficient joint secret key encryption-channel coding cryptosystem, based on regular Extended Difference Family Quasi-Cyclic Low-Density Parity-Check codes. The key length of the proposed cryptosystem decreases up to 85 percent using a new efficient compression algorithm. Cryptanalytic methods show that the improved cryptosystem has a significant security advantage over Ra...

pharmacy, being a profession which its activities are directly related to the health and wellbeing of the people and soci­ety has been described an ethical profession from earliest time. in the recent decades there has been a shift in the phar­macist role from dispensing to relationship with patients and health care providers and interfere the therapeutic process. other branches of pharmacy suc...