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Parameterised Compression for Sparse Bitmaps
 Proc. ACMSIGIR International Conference on Research and Development in Information Retrieval
, 1992
"... : Fulltext retrieval systems typically use either a bitmap or an inverted file to identify which documents contain which words, so that the documents containing any combination of words can be quickly located. Bitmaps of word occurrences are large, but are usually sparse, and thus are amenable to a ..."
Abstract

Cited by 30 (8 self)
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: Fulltext retrieval systems typically use either a bitmap or an inverted file to identify which documents contain which words, so that the documents containing any combination of words can be quickly located. Bitmaps of word occurrences are large, but are usually sparse, and thus are amenable to a variety of compression techniques. Here we consider techniques in which the encoding of each bitvector within the bitmap is parameterised, so that a different code can be used for each bitvector. Our experimental results show that the new methods yield better compression than previous techniques. Categories and Subject Descriptors: E.4 [Coding and Information Theory]: Data compaction and compression; H.3.2 [Information Storage]: File organisation . Keywords: Fulltext retrieval, data compression, document database, Huffman coding, geometric distribution, inverted file. 1 Introduction Fulltext retrieval systems are used for storing and accessing document collections such as newspaper a...
Is Huffman Coding Dead?
 COMPUTING
, 1993
"... In recent publications about data compression, arithmetic codes are often suggested as the state of the art, rather than the more popular Huffman codes. While it is true that Huffman codes are not optimal in all situations, we show that the advantage of arithmetic codes in compression performance is ..."
Abstract

Cited by 17 (3 self)
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In recent publications about data compression, arithmetic codes are often suggested as the state of the art, rather than the more popular Huffman codes. While it is true that Huffman codes are not optimal in all situations, we show that the advantage of arithmetic codes in compression performance is often negligible. Referring also to other criteria, we conclude that for many applications, Huffman codes should still remain a competitive choice.
Robust Universal Complete Codes for Transmission and Compression
 Discrete Applied Mathematics
, 1996
"... Several measures are defined and investigated, which allow the comparison of codes as to their robustness against errors. Then new universal and complete sequences of variablelength codewords are proposed, based on representing the integers in a binary Fibonacci numeration system. Each sequence is ..."
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Cited by 10 (4 self)
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Several measures are defined and investigated, which allow the comparison of codes as to their robustness against errors. Then new universal and complete sequences of variablelength codewords are proposed, based on representing the integers in a binary Fibonacci numeration system. Each sequence is constant and need not be generated for every probability distribution. These codes can be used as alternatives to Huffman codes when the optimal compression of the latter is not required, and simplicity, faster processing and robustness are preferred. The codes are compared on several "reallife" examples. 1. Motivation and Introduction Let A = fA 1 ; A 2 ; \Delta \Delta \Delta ; An g be a finite set of elements, called cleartext elements, to be encoded by a static uniquely decipherable (UD) code. For notational ease, we use the term `code' as abbreviation for `set of codewords'; the corresponding encoding and decoding algorithms are always either given or clear from the context. A code i...
Models of Bitmap Generation: A Systematic Approach to Bitmap Compression
 Inf. Proc. & Management, v28
, 1992
"... : In large IR systems, information about word occurrence may be stored in form of a bit matrix, with rows corresponding to different words and columns to documents. Such a matrix is generally very large and very sparse. New methods for compressing such matrices are presented, which exploit possible ..."
Abstract

Cited by 5 (2 self)
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: In large IR systems, information about word occurrence may be stored in form of a bit matrix, with rows corresponding to different words and columns to documents. Such a matrix is generally very large and very sparse. New methods for compressing such matrices are presented, which explways either given or clear from the context. A code i...
Models of Bitmap Generation: A Systematic Approach to Bitmap Compression
 Inf. Proc. & Management, v28
, 1992
"... : In large IR systems, information about word occurrence may be stored in form of a bit matrix, with rows corresponding to different words and columns to documents. Such a matrix is generally very large and very sparse. New methods for compressing such matrices are presented, which exploit possible ..."
Abstract

Cited by 5 (2 self)
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: In large IR systems, information about word occurrence may be stored in form of a bit matrix, with rows corresponding to different words and columns to documents. Such a matrix is generally very large and very sparse. New methods for compressing such matrices are presented, which expnd+How%3F+%28And+their+application+to+H.263%29&rft.jtitle=&rft.date=2000&rft.pages=&rft.genre=unknown&rft.aulast=Boncelet&rft.aufirst=+Charles&rft.au=Boncelet%2C+Charles">
Is Huffman Coding Dead?
, 1993
"... In recent publications about data compression, arithmetic codes are often suggested as the state of the art, rather than the more popular Huffman codes. While it is true that Huffman codes are not optimal in all situations, we show that the advantage of arithmetic codes in compression performance is ..."
Abstract
 Add to MetaCart
In recent publications about data compression, arithmetic codes are often suggested as the state of the art, rather than the more popular Huffman codes. While it is true that Huffman codes are not optimal in all situations, we show that the advantage of arithmetic codes in compression performance is often negligible. Referring also to other criteria, we conclude that for many applications, Huffman codes should still remain a competitive choice.