Keywords : Huffman coding


Enhancing Cost and Security of Arabic SMS Messages over Mobile Phone Network

Abdullah A. Abdullah

AL-Rafidain Journal of Computer Sciences and Mathematics, 2009, Volume 6, Issue 3, Pages 111-127
DOI: 10.33899/csmj.2009.163826

This paper investigates a novel algorithm for compressing and encrypting Arabic short text messages (SMS messages). Short text messages are used in cellular networks. Compression is required for saving the transmission energy or to use bandwidth in an efficient manner in addition to save the user money while the end-to-end effective encryption is required for security providence. This work succeeded to overcome small size limitation of the SMS message by changing Arabic characters coding from Unicode to Base64 coding scheme and developing a runt version of lossless Huffman coding scheme. Examples are shown where the application of the text compressor for short message services offering more than three times the capacity compared to a standard message.
 

New Method to Reduce the Size of Codebook in Vector Quantization of Images

Sahar K. Ahmed

AL-Rafidain Journal of Computer Sciences and Mathematics, 2005, Volume 2, Issue 1, Pages 53-62
DOI: 10.33899/csmj.2005.164067

The vector quantization method for image compression inherently requires the generation of a codebook which has to be made available for both the encoding and decoding processes. That necessitates the attachment of this codebook when a compressed image is stored or sent. For the purpose of improving the overall efficiency of the vector quantization method, the need arose for improving a means for the reduction of the codebook size.
In this paper, a new method for vector quantization is presented by which the suggested algorithm reduces the size of  the codebook generated in vector quantization. This reduction is performed by sorting the codewords of the codebook then the differences between adjacent codewords are computed. Huffman coding (lossless compression) is performed on the differences in order to reduce the size of the codebbook.