What are the as uses of Search Engine?
Introduction
A search Engine refers to a huge database of internet resources such as web pages, newsgroups, programs, images, etc. It helps to locate information on World Wide Web.
Users can search for any information by passing queries in form of keywords or phrases. It then searches for relevant information in its database and returns it to the user.
Search Engine Components
Generally, there are three basic components of a search engine as listed below:
- Web Crawler
- Database
- Search Interfaces
Web crawler
It is also known as a spider or bot. It is a software component that traverses the web to gather information.
Database
All the information on the web is stored in a database. It consists of huge web resources.
Search Interfaces
This component is an interface between user and the database. It helps the user to search through the database.
Search Engine Working
A web crawler, database, and search interface are the major components of a search engine that makes search engine work. Search engines make use of Boolean expression AND, OR, NOT to restrict and widen the results of a search. Following are the steps that are performed by the search engine:
- The search engine looks for the keyword in the index for a predefined database instead of going directly to the web to search for the keyword.
- It then uses software to search for the information in the database. This software component is known as web crawler.
- Once web crawler finds the pages, the search engine then shows the relevant web pages as a result. These retrieved web pages generally include the title of the page, size of the text portion, first several sentences, etc.
These search criteria may vary from one search engine to the other. The retrieved information is ranked according to various factors such as frequency of keywords, relevancy of information, links etc.
- User can click on any of the search results to open it.
Architecture
The search engine architecture comprises the three basic layers listed below:
- Content collection and refinement.
- Search core
- User and application interfaces
Search Engine Processing
Indexing Process
The indexing process comprises the following three tasks:
- Text acquisition
- Text transformation
- Index creation
Text acquisition
It identifies and stores documents for indexing.
Text Transformation
It transforms document into index terms or features.
Index Creation
It takes index terms created by text transformations and creates data structures to support fast searching.
Query Process
The query process comprises the following three tasks:
- User interaction
- Ranking
- Evaluation
User interaction
It supports the creation and refinement of the user query and displays the results.
Ranking
It uses queries and indexes to create a ranked list of documents.
Evaluation
It monitors and measures effectiveness and efficiency. It is done offline.
Examples
Following are the several search engines available today:
|
Search Engine |
Description |
|
|
It was originally called BackRub. It is the most popular search engine globally. |
|
Bingen |
It was launched in 2009 by Microsoft. It is the latest web-based search engine that also delivers Yahoo’s results. |
|
Ask |
It was launched in 1996 and was originally known as Ask Jeeves. It includes support for match, dictionary, and conversation questions. |
|
AltaVista |
It was launched by Digital Equipment Corporation in 1995. Since 2003, it is powered by Yahoo technology. |
|
AOL.Search |
It is powered by Google. |
|
Lycos |
It is top 5 internet portals and the 13th largest online property according to Media Matrix. |
|
Alexa |
It is a subsidiary of Amazon and used for providing website traffic information. |
