1. Chapter Five Web Search Engines
Information Technology Department
Bryar Hassan (BSc & MSc Eng.)

2. Contents What is a Search Engine Need of Search Engine
How Search Engine Works?
Types of Search Engines
Web Crawler
SEO – Search Engine Optimization
Internet Technology – First Year

3. What is a Search Engine
A search engine is a searchable database which collects information on web pages from the Internet.
Indexes the information and then stores the result in a huge database where it can be quickly searched.
The search engine provides an interface to search the database.
When you enter a keyword into the search engine, the search engine will look through the billions of web pages to help you find the ones that you are looking for.
Internet Technology – First Year

4. Examples of Search Engines
Internet Technology – First Year

5. Need of Search Engine
Variety: An Internet search can generate a variety of sources for
information. This variety allows anyone searching for information to choose the types of sources they would like to use, or to use a variety of sources to gain a greater understanding of a subject.
Organization: Internet search engines help to organize the Internet and individual websites.
Precision: Search engines do have the ability to provide refined or more precise results.
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6. Searching for a keyword
Searching for the keyword “thapar google
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7. How Search Engine Works?
A Search engine has three parts:
Spider: Deploys a robot program called a spider or robot designed to track down web pages. It follows the links these pages contain, and add information to search engines’ database.
Example: Googlebot (Google’s robot program)
Index: Database containing a copy of each Web page gathered by the spider.
Search engine software: Technology that enables users to query the index and that returns results in a schematic order.
Internet Technology – First Year

8. How Search Engine Works?
Internet Technology – First Year

9. Types of Search Engines
Text Search Engines
General: AltaVista, Ask Jeeves, Bing, Google
Specialized: Google Scholar, Scirus, Citeseer
Image Search Engines - How can we search on the Image content
Video Search Engines - Image Search with Time dimension
Crawler Powered Indexes - google.com
Human Powered Indexes
Hybrid Models - Submitted URLs to a search engine
Semantic Indexes
- Semantic search seeks to improve search accuracy by understanding the searcher's intent and the contextual meaning of terms as they appear in the searchable dataspace, whether on the Web or within a closed system, to generate more relevant results.
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10. Web Crawler
A Web crawler is a computer program that browses the World Wide Web in a methodical, auto mated manner.
Other names
Crawler
Spider
Robot (or bot)
Web agent
Wanderer, worm
Examples: googlebot, msnbot, etc.
- Crawler: a program that systematically browses the World Wide Web in order to create an index of data.
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11. Web Crawler Architecture
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12. Application of Crawling Concept
Search Engine Optimization (SEO) is the process of affecting the visibility of a website or a web page in a search engine's unpaid results, often referred to as "natural," "organic," or "earned" results.
Internet Technology – First Year

13. SEO – Search Engine Optimization
Internet Technology – First Year