SEARCH ENGINES

By,

CH.KRISHNA MANOJ(Y5CS021),

3/4 B.TECH,

VRSEC.04/19/23 1

CONTENTS

• INTRODUCTION • TYPES OF SEARCH ENGINES• COMPONENTS OF SEARCH ENGINE• SEARCH RESULTS IN A SEARCH ENGINE• ADVANTAGES• DISADVANTAGES• FUTURE SEARCH ENGINE

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What is a Search Engine?

• Search: computing to examine a computer file, disk, database, or network for particular information.

• Engine: something that supplies the driving force or energy to a movement, system, or trend.

• Search engine: a 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

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Why is the search engines necessary?

• With an estimated 800 million web pages finding the one you want is difficult!

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Types of Search Engines

• Three are three types of search engines:

• 1.Automatic search engines:These rely on "software spiders" to index Web sites. You submit your page to a search engine, and the spider will index your entire site.

e.g. Google , Altavista , etc...

• 2.Classified Directory:These rely on submissions

from users and Web site owners to populate

their indexes.

e.g. Msn, Yahoo! , Aol search ,etc......

• 3.Meta-Search Engine: These uses the

multiple automatic search engines.

e.g. Dogpile, Web crawler,etc...........04/19/23 5

Components of a Search Engine

• There are four basic tasks:• 1.web crawler(spider or robot):

• collects pages• checks for page changes

• 2.Indexer:• constructs a sophisticated file structure to enable fast page retrieval

• 3.Searcher:• satisfies user queries

• 4.Ranking results:• results ordered from most relevant to least

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Search Results

• Presented as links

• Supposedly ordered in terms of relevancy to the query

• Some Search Engines score results

• Normally organised if groups of ten per page

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Role of search engines in the internet

• The big is getting bigger, and the rich is getting richer.

• Google -74.8%

• Yahoo-13.8%

• msn-6.4%

• Aol-2.6%

• Ask-1.2%

• Others-1.2%

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Google architecture

• URL server sends list of URLs to be fetched to crawlers

• StoreServer compresses and stores pages

• Indexer extracts words, their pos., size, capital.

• Anchors cont.links and their text

• Sorter generates inverted index

• Searcher uses Lexicon, II, and PR

ADVANTAGES OF SEARCH ENGINES:

• Very easy to use

• Normally global

• The indexes of search engines are usually vast, representing significant portions of the Internet, offering a wide variety and quantity of information resources.

• The growing sophistication of search engine software enables us to precisely describe the information that we seek.

• Search engine marketing consists primarily of search engine optimisation and pay-per-click search advertising.

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DISADVANTAGES OF SEARCH ENGINES:

• Links are often out of date

• Usually too many links are returned

• Returned links are not very relevant

• The Engines don't know about enough pages

• Different engines return different results

• Rankings are sometimes questionable because they are computer-generated rather than human produced.

• Lack of human involvement can lead to poor quality control.

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Reference books

• Emery, Vince. How to Grow Your Business on the Internet. 3d Ed. Scottsdale, AZ: Coriolis Group, 1997.

• Greenberg, Karl. "Search Patterns." Brandweek. September 11, 2000.

• John, Lauren. "Wanted: As More of the IT Universe Moves to the Web, Search Engines Are Being Used to Take on Increasingly Complex Business Functions." Computerworld. July 3, 2000.

• Korper, Steffano, and Juanita Ellis. The E-Commerce Book: Building the E-Empire. San Diego, CA: Academic Press, 2000.

• Regan, Keith. "Does E-Commerce Need Search Engines?" E-Commerce Times. October 18, 2000.

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