Mata search engine


A metasearch engine is a search tool[1] that sends user requests to several other search engines and/or databases and aggregates the results into a single list or displays them according to their source. Metasearch engines enable users to enter search criteria once and access several search engines simultaneously. Metasearch engines operate on the premise that theWeb is too large for any one search engine to index it all and that more comprehensive search results can be obtained by combining the results from several search engines. This also may save the user from having to use multiple search engines separately.
The term "metasearch" is frequently used to classify a set of commercial search engines, see the list of search engines, but is also used to describe the paradigm of searching multiple data sources in real time. The National Information Standards Organization (NISO) uses the terms Federated Search and Metasearch interchangeably to describe this web search paradigm.

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[edit]Operation


architecture of a metasearch engine
Metasearch engines create what is known as a virtual database. They do not compile a physical database or catalogue of the web. Instead, they take a user's request, pass it to several other heterogeneous databases and then compile the results in a homogeneous manner based on a specific algorithm.
No two metasearch engines are alike[2]. Some search only the most popular search engines while others also search lesser-known engines, newsgroups, and other databases. They also differ in how the results are presented and the quantity of engines that are used. Some will list results according to search engine or database. Others return results according to relevance, often concealing which search engine returned which results. This benefits the user by eliminating duplicate hits and grouping the most relevant ones at the top of the list.
Search engines frequently have different ways they expect requests submitted. For example, some search engines allow the usage of the word "AND" while others require "+" and others require only a space to combine words. The better metasearch engines try to synthesize requests appropriately when submitting them[citation needed].

[edit]See also

For engines, see the list of search engines
  • Search aggregator
  • Travelfox
  • Federated search
  • Metabrowsing
  • Multisearch
  • Travel website

  • Metasearch engines

    See also: Metasearch engine

    Overview table: Identification Systems, their features and scope


    Identification System
    Year of creation
    Level of granularity
    Category
    Community present in the Governing Board
    Standard
    Agencies
    Actionability/
    Persistence
    ISBN
    (International Standard Book Number)
    1972
    Manifestation
    Intelligent
    Publishers/Libraries
    ISO 2108
    Yes
    No
    ISSN
    (International Standard Serial Number)
    1974
    Manifestation
    Dumb
    Libraries
    ISO 3297
    Yes
    No
    ISRC
    (International Standard Recording Code)
    1986
    Expression
    Intelligent
    Music producers
    ISO 3901
    Yes
    No
    SICI
    (Serial Item and Contribution Identifier Standard)
    1991
    Expression
    Intelligent
    Not relevant (but operational in libraries)
    ANSI/NISO Z39.56-1996
    No
    No
    ISMN
    (International Standard Music Number)
    1993
    Manifestation
    Intelligent
    Music Publishers/Libraries
    ISO 10957
    Yes
    No
    ISRN
    (International Standard Report Number)
    1994
    Expression
    Intelligent
    Not relevant (but operational in libraries)
    ISO 10444
    No
    No
    DOI
    (Digital Object Identifier)
    1998
    Object
    Dumb
    Publishers (but open to libraries)
    Syntax conforms to ANSI/NISO Z39.84-2000
    Yes
    Yes
    ISAN
    (International Standard Audiovisual Number)
    2000
    Work/Expression
    Dumb
    Audiovisual Producers
    ISO 15706
    Yes
    No
    ISWC
    (International Standard Musical Work Code)
    2000
    Work
    Dumb
    Authors/Composers
    ISO 15707
    Yes
    No


      

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