System Design Of Extensive Metasearch Engine (EMSE)

Along with the fast increment of the information on the Internet, search engine has become an important information retrieval tool and developed rapidly in recent years. Metasearch engine is a new kind of software constructed between the users and the underlying search engines. To use information resources adequately and to reduce new inputs, it becomes one of the hottest research problems to the information service organizations.This thesis starts from the concepts of search engine and metasearch engine and introduces their background technologies, realizing principles and developmental statuses. To extend the function and searching range of metasearch engines, extensive metasearch engine (EMSE) was put forward. It can search other kinds of databases besides search engines, such as OPAC, online databases and news websites.Based on the comprehensive researches on the existing metasearch engines, this thesis discusses the techniques used and the problems met in realizing metasearch engines. After that, it gives the approaches of database selection, document selection, database accessing and result merging and the system design of EMSE. At the end of this thesis, the further ameliorations and the future development of EMSE are discussed.