A Study About The Heterogeneities In Meta-engine Systems

Frequently, a user's desired information is stored in the databases of multiple search engines. To satisfy his information needs, he must invoke multiple search engines and identify useful documents from the returned results respectively. That's inefficient and inconvenient. To support unified access to multiple search engines, a meta-engine can be constructed. When a meta-engine receives a query from a user, it invokes the underlying search engines to retrieve useful information for the user. But the heterogeneities exist among the component engines may damage the effectiveness of this distributed retrieval. To overcome the impact of these heterogeneities, all possible heterogeneous problems in the meta-engine environment must be identified and tackled carefully.In this dissertation, we will survey techniques that have been proposed to tackle several main heterogeneous problems for building a good meta-engine, namely, the database selection problem, the document selection problem and the result merging problem. We will also present our approaches to these problems and point out some problems that need to be further researched.