Transcript Web Search Enginesx

Chapter Five
Web Search Engines
Information Technology Department
Bryar Hassan (BSc & MSc Eng.)
[email protected]
Contents
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What is a Search Engine
Need of Search Engine
How Search Engine Works?
Types of Search Engines
Web Crawler
SEO – Search Engine Optimization
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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.
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Examples of Search Engines
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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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Searching for a keyword
• Searching for the keyword “thapar university” @ google
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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.
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How Search Engine Works?
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Types of Search Engines
• Text Search Engines
– General: AltaVista, Ask Jeeves, Bing, Google
– Specialized: Google Scholar, Scirus, Citeseer
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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
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Web Crawler
• A Web crawler is a computer program that browses the World Wide
Web in a methodical, auto mated manner.
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Crawler
Spider
Robot (or bot)
Web agent
Wanderer, worm
• Examples: googlebot, msnbot, etc.
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Web Crawler Architecture
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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.
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SEO – Search Engine Optimization
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