Design of an Enhanced Rule Based Focused Crawler

The rapid growth of World Wide Web has urged the development of retrieval tools like search engines. Topical crawlers have gained large momentum in recent years. In this paper, a parallel web spider model, based on multi-agent system for cooperative information gathering is presented. The system collects Web pages that are on topic. The system employs two types of agents: retrieval and master agents. Master agents are responsible for disseminating crawling frontiers to individual retrieval agents. The URL frontier is built by a rule based engine which decides the next URL to be downloaded. The retrieval agents coordinate among themselves in order to avoid downloading non productive and duplicate Web pages. The empirical results clearly depict the advantage of rule based design in terms of harvest rate and time.