Compressed-Domain Text Indexing and Retrieval

这个项目研究了文本压缩和文本检索之间的相互作用，旨在建立一个并行的文本检索系统，称为Codir，允许压缩域的文本索引和检索。最终，Codir期望能够有效地响应由一个或多个通过布尔运算符连接的“关键字”组成的查询，并且文本数据库中的文档要么包含这些关键字，要么其“主题”与关键字匹配。Codir最重要的特性是它提供的灵活性，允许空间/时间权衡，并在动态索引缓存中使用这种灵活性。Codir开发的技术将应用于两个目标应用领域：网页搜索和使用字幕的视频访问。本项目对文本检索领域的预期贡献是：(1)在统一框架中集成文本压缩和文本检索的性能权衡；(2)详细描述了Codir在生产模式下使用的访问模式和查询统计；(3)开发支持近似关键字搜索和文本数据库频繁就地更新的新技术；(4)将术语加权和主题索引等高级文本分类技术纳入Codir的实现框架。该项目开发的技术有望对企业信息库、互联网搜索引擎和大型基于文本的Web服务器的设计人员有用。

This project investigates the interaction between text compression and text retrieval, and aims to build a parallel text retrieval system called Codir that allows compression-domain text indexing and retrieval. Ultimately, Codir is expected to be able to efficiently respond to queries consisting of one or multiple "keywords" connected via Boolean operators, with documents in the text database that either contain those keywords, or whose "theme" matches the keywords. The most important feature of Codir is the flexibility it provides to allow space/time tradeoff and the use of this flexibility in the Dynamic Index Cache. The two target applications areas to which the technologies developed in Codir are to be applied to are Web Page Searching and Video Access using Captioning. The expected contributions of this project to the text retrieval field are: (1) the performance tradeoffs of integrating text compression and text retrieval in a unified framework; (2) the detailed characterization of the access patterns and query statistics of a production-mode use of Codir; (3) the development of new techniques to support approximate keyword search and frequent in-place updates to the text database; (4) the incorporation of advanced text classification techniques such as term weighting and theme indexing into the implementation framework of Codir. The technologies developed from this project are expected to be useful to designers of corporate information repository, internet search engines, and large-scale text-based Web servers.