摘要
倒排文档是信息检索系统中最普遍使用的索引机制 ,而索引文件的压缩能大大提高检索速度和节约磁盘空间。倒排文件压缩的传统做法是文档 (标识号 )间距法 (d- gaps)。然而 ,剧烈变化的间距值并不能被著名的前缀自由代码有效编码压缩。为了使间距值得到有效的压缩 ,本文设计了一个文档标识号重置法。模拟试验表明能更有效压缩 d- gaps倒排文档。
The inverted file is the most popular indexing mechanism in an information retrieval system. Compressing an inverted file can greatly improve document search rate and save disk space. Traditionally, the d-gaps technique is used in the inverted file compression by replacing document identifiers with usually much smaller gap values. However, fluctuating gap values cannot be efficiently compressed by some well-known prefix-free codes. In this paper, a document identifier reassignment algorithm is proposed to reduce the gap values. Simulation results show that the average gap values of the inverted files can be reduced effectively.
出处
《现代图书情报技术》
CSSCI
北大核心
2004年第8期61-65,共5页
New Technology of Library and Information Service
