Yair Wiseman

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A simple parallel algorithm for decoding a Huffman encoded file is presented, exploiting the tendency of Huffman codes to resynchronize quickly, i.e. recovering after possible decoding errors, in most cases. The average number of bits that have to be processed until synchronization is analyzed and shows good agreement with empirical data. As Huffman coding(More)
We explore the possibility of using multiple processors to improve the encoding and decoding times of Lempel–Ziv schemes. A new layout of the processors, based on a full binary tree, is suggested and it is shown how LZSS and LZW can be adapted to take advantage of such parallel architectures. The layout is then generalized to higher order trees.(More)
We explore the use of compression methods to improve the middleware-based exchange of information in interactive or collaborative distributed applications. In such applications, good compression factors must be accompanied by compression speeds suitable for the data transfer rates sustainable across network links. Our approach combines methods that(More)
Conventional gang scheduling has the disadvantage that when processes perform I/O or blocking communication, their processors remain idle because alternative processes cannot be run independently of their own gangs. To alleviate this problem, we suggest a slight relaxation of this rule: match gangs that make heavy use of the CPU with gangs that make light(More)
We explore the use of the LZW and LZSS data compression methods. These methods or some versions of them are very common in use of compressing different types of data. Even though on average LZSS gives better compression results, we determine the case in which the LZW perform best and when the compression efficiency gap between the LZW algorithm and its LZSS(More)
Recently, the use of the Burrows-Wheeler method for data compression has been expanded. A method of enhancing the compression efficiency of the common JPEG standard is presented in this paper, exploiting the Burrows-Wheeler compression technique. The paper suggests a replacement of the traditional Huffman compression used by JPEG by the Burrows-Wheeler(More)
Several simulations for parallel collision detection have been suggested during the last years. The algorithms usually greatly depend on the parallel infrastructure and this dependency causes in many times non-scalability performance. The dependency also harms the portability of the simulation. This paper suggests a scalable and portable parallel algorithm(More)