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Lempel
Abraham Lempel ( he, אברהם למפל, born 10 February 1936) is an Israeli computer scientist and one of the fathers of the LZ77 and LZ78, LZ family of lossless data compression algorithms. Biography Lempel was born on 10 February 1936 in Lviv, Lwów, Poland (now Lviv, Ukraine). He studied at Technion - Israel Institute of Technology, and received a Bachelor of Science, B.Sc. in 1963, Master of Science, M.Sc. in 1965, and Doctor of Science, D.Sc. in 1967. Since 1977 he has held the title of full professor. Lempel is now a professor emeritus in Technion. His historically important works start with the presentation of the LZ77 and LZ78, LZ77 algorithm in a paper entitled "A Universal Algorithm for Sequential Data Compression" in the ''IEEE Transactions on Information Theory'' (May 1977), co-authored by Jacob Ziv. He is the recipient of the 1998 Golden Jubilee Award for Technological Innovation from the IEEE Information Theory Society; and the 2007 IEEE Richard W. Hamming Medal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LZ77 And LZ78
LZ77 and LZ78 are the two lossless data compression algorithms published in papers by Abraham Lempel and Jacob Ziv in 1977 and 1978. They are also known as LZ1 and LZ2 respectively. These two algorithms form the basis for many variations including LZW, LZSS, LZMA and others. Besides their academic influence, these algorithms formed the basis of several ubiquitous compression schemes, including GIF and the DEFLATE algorithm used in PNG and ZIP. They are both theoretically dictionary coders. LZ77 maintains a sliding window during compression. This was later shown to be equivalent to the ''explicit dictionary'' constructed by LZ78—however, they are only equivalent when the entire data is intended to be decompressed. Since LZ77 encodes and decodes from a sliding window over previously seen characters, decompression must always start at the beginning of the input. Conceptually, LZ78 decompression could allow random access to the input if the entire dictionary were known in ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |