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WebCrawler by Brian Pinkerton University of Washington. - Vamsheedhar Reddy Alija. What is a WebCrawler. It is a program which browses Worldwide Web in a methodical and automated manner.
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WebCrawlerby Brian Pinkerton University of Washington - Vamsheedhar Reddy Alija
What is a WebCrawler • It is a program which browses Worldwide Web in a methodical and automated manner. • Creates a copy of all the visited pages for later reference by the search engine. • It is a software agent that starts with a list of URL’s to visit, as it visits these URL’s identifies all the hyperlinks in that pages and adds it to the list it has to visit recursively.
WebCrawler • Sensors : The URL’s and the Hyperlinks • Effectors : Its Database • Environment : Software Environment – WWW (Worldwide Web) • Agent : WebCrawler is a Software agent.
Google Crawler (Brin and Page in 1998) • Like any search engine doesn’t search the entire Web ( just the 16% ) • Has some links to start with initially ( URL Server) • In “ Google ” depending on the number of hits updates it • So each time we do a same search we might not get the same results • If our search is not useful it tries to change from its basic set • If a URL has been searched previously….
Other WebCrawlers • FAST Crawler for FAST search engine • Internet Archive Crawler • WebSPHINX
References • http://www.thinkpink.com/bp/WebCrawler/History.html • http://en.wikipedia.org/wiki/Webcrawler