Abstract
The "concordance" of an information retrieval system can often be stored in form of bit-maps, which are usually very sparse and should be compressed. Hierarchical bit-vector compression consists of partitioning a vector into equi-sized blocks, constructing a new bit- vector Vi+1which points to the non-zero blocks in Vi, dropping the zero-blocks of Viand repeating the process for Vi+1- We refine the method by pruning some of the tree branches if they ultimately point to very few documents; these document numbers are then added to an appended list which is compressed by the prefix-omission technique. The new method was thoroughly tested on the bit-maps of the Responsa Retrieval Project, and gave a relative improvement of about 40% over the conventional hierarchical compression method.
Original language | English |
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Title of host publication | Proceedings of the 9th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, SIGIR 1986 |
Editors | Fausto Rabitti |
Publisher | Association for Computing Machinery, Inc |
Pages | 88-96 |
Number of pages | 9 |
ISBN (Electronic) | 0897911873, 9780897911870 |
DOIs | |
State | Published - 1 Sep 1986 |
Event | 9th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, SIGIR 1986 - Pisa, Italy Duration: 8 Sep 1986 → 10 Sep 1986 |
Publication series
Name | Proceedings of the 9th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, SIGIR 1986 |
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Conference
Conference | 9th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval, SIGIR 1986 |
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Country/Territory | Italy |
City | Pisa |
Period | 8/09/86 → 10/09/86 |
Bibliographical note
Publisher Copyright:© Organization of the 1986-ACM Conference on Research and Development in Information Retrievel.