E. Schuegraf. Compression of Large Inverted Files with Hyperbolic Term Distribution. Information Processing and Management, (4):377--384, 1976.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....required for the uncompressed original map. Alternatively, one could record the distances between successive 1 bits, that is, give the position of a 1 bit relative to the preceding 1 bit position rather than relative to the beginning of the vector. This is known as run length coding (Schuegraf [14]) In its simplest form, the length of every run is encoded by a fixed length codeword; since this codeword must be large enough to accommodate the theoretical maximum run length, this is equivalent to the previous method. Since, in simple run length coding, the space allocated for each run must ....

Schuegraf E.J., Compression of large inverted files with hyperbolic term distribution, Inf. Proc. and Management 12 (1976) 377--384.

....compression This paper combines and extends preliminary versions that were presented at the DCC 91 Conference in Snowbird, Utah, and at the SIGIR 91 Conference in Chicago. 1 rates of up to 95 have been reported. Techniques for compressing bitmaps include variants of run length coding [17], 18] Huffman coding [12] 10] and hierarchical methods [19] 6] All of these try to compress each bitmap independently from the others. In [3] a new method is introduced that attempts to improve compression efficiency of a set of bitmaps by collecting similar maps into clusters. In the ....

Schuegraf E.J., Compression of large inverted files with hyperbolic term distribution, Inf. Proc. and Management 12 (1976) 377--384.

....code, and with a batched variant, where the code was selected according to blog p w c. Again there is a small, but definite, improvement in the compression performance. 8 Comparison with Other Methods There has been a great deal of previous work on bitmap compression, and many methods proposed [1, 2, 3, 4, 5, 8, 12, 17, 19, 21]. It is interesting to compare the compression possible with the parameterised models with those previous methods. Compression Manuals GNUbib Comact Huffman (global) 49.8 32.3 25.9 Global model 0.5 0.7 0.1 Total 50.3 33.0 26.0 Huffman (batched) 44.1 30.2 24.6 dlog Ne models 1.6 0.9 0.2 ....

E.J. Schuegraf. Compression of large inverted files with hyperbolic term distribution. Information Processing & Management, 12:377--384, 1976.

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E. Schuegraf. Compression of Large Inverted Files with Hyperbolic Term Distribution. Information Processing and Management, (4):377--384, 1976.

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