JAI Narai college of tech. bhopal

SUBMITTED BY:Rishabh AgrawalSUBIMTTED TO:AVENASH SIR

INDEX• INTRODUCTION• WORKING• FACTS• ADVANTAGE• LIMITATIONS• USES

Search Engines

What is a Search Engine?

• Software that enables users to search the Internet or Intranet using keywords.• A program that acts as a catalogue for the Internet or Intranet.• A web search tool that automatically visits websites (using crawlers), records and indexes them within its

database, and generates results based on a user's search criteria.

Popular Search Engines

dictionary definitionssearch

COMPUTING (transitive verb) to examine a computer file, disk, database, or network for particular information

enginesomething that supplies the driving force or energy to a movement, system, or

trend

search enginea computer program that searches for particular keywords and returns a list of

documents in which they were found, especially a commercial service that scans documents on the Internet© Tefko Saracevic 4

Search Engines

How do they work?

• Web CrawlingAutomated “spider” that follows links and then analyses content in pages to determine what should be indexed. Metadata is very important in this phase.

• IndexingData about web pages are stored in an index database for use in later queries. Some search engines, such as Google, store all or part of the source page (referred to as a cache) as well as information about the web pages.

• Searching & ResultsThe engine looks up the index and provides a listing of best-matching web pages according to its criteria. The usefulness of a search engine depends on the relevance of the result set it gives back.

Search Engines

University Search Engine Statistics

• The University uses Microsoft SharePoint Portal Server 2003• ~88,000 web pages are crawled every day• The crawl starts at 6:00am every day• The crawl takes ~ 20 minutes to complete• The search engine is currently crawling:

– www.unisa.edu.au– www.unisanet.unisa.edu.au– www.library.unisa.edu.au

elaboration…similarities, differences

• all search engines have these basic parts in common

• BUT the actual processes – methods how they do it – are based on various algorithms & they differ – most are proprietary with details kept mostly secret but

based on well known principles from information retrieval or classification

– to some extent Google is an exception – they published their method

© Tefko Saracevic 7

limitations• every search engine has limitation as to

– coverage• meta engines just follow coverage limitations & have more of

their own

– search capabilities– finding quality information

• some have compromised search with economics – becoming little more than advertisers © Tefko Saracevic 8

use of search engines … among others

© Tefko Saracevic 9

Search Engines

When I search I don’t get good results …

Four possible causes:

• No ContentThere is no content that matches your search query.

• Bad search phrasesYou are putting in really bad search phrases!

• Bad search engineThe search engine isn’t very good, or isn’t searching the content that it should be.

• Bad contentThe content that you want exists, but the metadata and text within the page is not optimised for a search engine.

how to find a search engine?

• variety of resources that list or categorize engines• SearchEngines.com

search for engines by topic, geography, reference

Search Engine Guideengines categorized by topic; other engine information

Search Engine Colossus – international directory of search engines by country, topic from 198 countries and 61

territories; engines in choice of languages

Phil Bradley’s country based search enginesover 2000 serach engines from countries all over the globe© Tefko Saracevic 11

where to find out?• information about search engines in sources that

have updates, news, tips for searching and more – a MUST for searchers :– Search Engine Watch

• ratings, news, statistics, charts, explanations, tutorials

– Search Engine Showdown • “The users’ guide to web searching” - run by a librarian, news links, ratings

Virtual Chase a site about “Teaching Legal Professionals How To Do Research;,” this section

has very good tips and links for consideration of quality on the web© Tefko Saracevic 12

THANK YOU