This document provides an overview of search engines, including their history, how they work, types of search engines, and advantages. It discusses early search tools like Archie and Gopher. It describes how search engines use spiders and robots to index webpages and how they rank results based on factors like page rank and keyword frequency. The document also outlines the different modules of a search engine and concludes by emphasizing the important role search engines play in accessing online information.

1. RUCHIR KUMAR GUPTA
BTECH FINAL YEAR(I.T.)
0701013084

2. CONTENTS
INTRODUCTION
HISTORY
WORKING
TYPES OF SERCH ENGINE
ADVANTAGES
CONCLUSION

3. INTRODUCTION
Search engine is a software program that
searches for sites based on the words that you
designate as search terms.
Search engines look through their own
databases of information in order to find what
it is that you are looking for.
“Search engine” is the popular term for an
Information Retrieval (IR) system.

4. HISTORY
Archie – First search tool for the Internet
Gopher – indexed plain text documents
Jughead – searched the files stored in Gopher
index system.
Wandex – first Web search engine

5. How do Search Engine Works
 Spiders
 Robots

6. FORMULA
Larry Page and Sergin Brin at Stanford University gave it.
 PA=(1-d)+d (PR(T1))/C (T1)+…+PR (Tn)/C (Tn)
Where
 PR(A): Page Rank of page A
 PR(Ti): Page Rank of pages Ti which link to page A.
 C(Ti): the no of outbound link on page Ti d: damping
factor in the range of 0<d<1,usually set to 0.85.
The highest the PR, the better the inbound link, so it would
seem.

11. APPROXIMATING
RELEVANCE
 Statistical similarity is used to estimate the relevance of
an query to answer.
 Consider the query MAHENDRA SINGH DHONI
1) A good answer contains all three words,and more
frequently the better,we called this term frequency (TF).
2) Some query terms are are more important-have the
discriminatory power-better than others.

12. Resolving a Query
Consider ( cat hat mat )
Select a word from query ( “cat” )
Retrieve the list for the word cat
Find the best ranked document and look up the
mapping table.
Retrieve and Summarize the docs.

13. Search Engine Modules :
A document processor
A query processor
A search and matching function
A ranking capability
 Summarizing and Presenting documents.

14. TYPES OF SEARCH ENGINE
Crawler-Based Search Engines
Human-Powered Directories
Hybrid Search Engines" Or Mixed Results

15. Google use spiders
Large index of keywords.
Google’s PAGE RANK .
1.frequency and location of keywords
within the Web page
2. Web page history.
3. number of other Web pages that link
to the page in question

16. ADVANTAGES
 It organizes the world ‘s information.
 It makes the information universally accessible.
 It makes the information useful.
 Helps people to interact one another.
 Helps to know about the products and goods.
 Helps the people to know about the society.
 Any information can be gathered from google.

17. CONCLUSION
Search engine plays important role in
accessing the content over the internet, it
fetches the pages requested by the user.
 It made the internet and accessing the
information just a click away.
The need for better search engines only
increases
The search engine sites are among the most
popular websites.