Review on Distributed Search Engine Model

This paper reviews the model,structure and search method for distributed search engine,and then discusses the evaluation of search engines. From the offline processing and online processing,the basic modules of search engine are discussed. The essential factor of search engine performance is determined by the online search processing. Divided from the distributed search engine model,the search engine consists of four main subsystems: Web crawler system,building index system,retrieval system and log analyzing system. The inverted index is divided into document ids and term frequency( or influence) sequence,which is composed of the dictionary structure and inverted file. Then the paper discusses the typically three types strategies of query processing for the current search eninge,and compares their adaptiation conditions. Finally,the two improtant indicators of evaluation of search engines are reviewed and enumerated the quantitative evaluation formula,which are query efficiently and quality of results,respectively.