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Search Engines



Search engine basics and types

Search engine basics and types



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Search Engines Search Engines Presentation Transcript

  • Search Engines Shamprasad Pujar IGIDR, Mumbai [email_address]
  • Agenda
    • Basics of Internet
    • Basics of Search engine
    • What is a search engine?
    • Functioning of a search engine
    • Methods of indexing or searching
    • Types of Search engines?
    • Advantages of Search engines?
    • Disadvantages of Search engines?
    • Search engines v/s Directories v/s portals
    • Limitations of search engines
    • Q & A
  • Basics of Internet
    • Anybody can publish anything on the net
    • Content and features of sites change very fast
    • No bibliographic control on published information
    • Internet is a self publishing tool-Evaluate
    • Try out multiple sites, while looking for information
    • Subject Directories and Search Engines vary in their contents
    • Subject Directories/Search engines are highly volatile
    • Good source to locate scholarly literature
  • Basics of Search Engines
    • Store millions of pages in their databases
    • Sites are included automatically based on a set criteria. No human interference
    • Search features/scope vary greatly from one to another
    • Good for beginners and experts
    • Good for searching on a narrow topic
    • Search for particular types of documents, file types, etc is possible
    • Search for any kind of information is possible
    • Different search facility is available for sites, images, news, audio/video files, maps etc
  • What is a Search Engine?
    • Search engine is a tool, which helps in retrieving
    • information from the Internet
    • It indexes the web and accordingly builds its databases
    • Each search engine has its own set rules to index
    • websites
    • When the query or keyword is entered in the search
    • box it checks its ‘index’ with the query
    • Relevant matches are retrieved and returned as 'hits' or
    • 'search results‘
  • Functioning of Search Engine?
  • Methods of Indexing and Searching
    • Keywords from meta tags or web pages
    • Boolean (and, or, not)
    • Mathematical symbols (+, * -)
    • Concept /Computational
    • Natural language searching
  • Types of Search Engines
    • General
        • Example: Bing, Google, Gigablast, etc
    • Meta Search Engines
    • Example: Dogpile, etc
    • Subject Specific search engine
    • Example: Scirus, Intute, Entrez, GoPubMed
    • Intelligent/Specialized Search Engines
    • Example: Kosmix, WolframAlpha
    • Deep Web/Invisible web
    • Example: Library catalogues, Databases
    • Scholarly literature
    • Example: Google Scholar, Base, OAISTER, etc
  • Types of Search Engines
    • General Search Engines :
    • Have own database/index
    • Index sites using their software robot/crawler
    • Index sites on their policy
    • Rank web pages based on their policy
    • Meta Search Engines
    • Search different general search engines
    • Components
    • Dispatch mechanism  Interface Agents  Display
  • Types of Search Engines
    • Subject Specific Search Engines:
    • Index sites on particular subject or material
    • Intelligent/Specialized Search Engines:
    • Concept based searching
    • Allow natural language searching
    • Use thesaurus
    • Personalized Services
    • Deepweb or Inivisible Web:
    • Search content stored in searchable databases
    • Scholarly Literature Search Engines
    • Search content from scholarly journals publishers websites/grey literature published from institutes and repositories
  • Advantages of Search Engines
    • Enable to quick search to vast amount of information from one search box
    • Search on a specific type or piece of
    • information is possible
    • Different types of search engines enable to look for specific types of documents
  • Disadvantages of Search Engines
    • Creates information overload
    • Semantic search is not possible
    • Privacy and security is of concern
    • Makes everyone to dependent
  • Search Engines v/s Directories v/s Portals
    • Crawl Web for information
    • Automatic Indexing
    • Change in webpage automatically gets updated
    • Human editing
    • Change in webpage will not automatically updated
    • Information put by individuals or organizations
  • Limitations of Search Engines
    • Can not index the entire web. Most of the search engines can index only between 40% and 60% of the web
    • Can not index sites governed by passwords and developed using frames
  • Q & A
    • Questions and Answers ??