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Searching the World Wide Web. CMP 101 Introduction to Information Systems. L02. Internet Search. What is the World Wide Web?. Billions of Documents Accessible via the Internet Viewed by a web browser . Web documents contain hyperlinks

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Searching the World Wide Web

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Searching the World Wide Web

CMP 101

Introduction to

Information Systems

L02. Internet Search


What is the World Wide Web?

  • Billions of Documents

    • Accessible via the Internet

    • Viewed by a web browser.

  • Web documents contain hyperlinks

    • Allow readers to jump from one web document to another

    • Gateways to audio and video broadcasts, animations, and more.


What is a Search Engine?

  • A collection of software

    • Locates words on web pages

    • Ranks and indexes the words

    • Creates a database that you can search.

  • When using a search engine, you search the database that has been created (not the Web).


How Does a Search Engine Work?

  • Robots, Spiders, Crawlers – Oh My!

    • visits web pages

    • collects words and hyperlinks

    • gives words to the search engine for ranking and indexing

    • differing strategies for crawling yield different results


How Does a Search Engine Work?

  • Ranking and Indexing

    • Meta-information

      • the number of times a word appears on a page

      • the word’s location on a page

      • other much more sophisticated information.

    • differing strategies yield different results


Subject Directories

  • Categorical listing of topics with links to individual web sites.

  • Created with the help of human editors

  • Editors rate and rank the sites

  • Good for narrowing down a topic or browsing a large list of topics.

    Examples include: Yahoo! Directory (dir.yahoo.com), and Gigablast (gigablast.com).


Individual Search Engines

  • Create and maintain a database of indexed and ranked words for searching.

  • Good to use if looking for specific information about a topic.

    Examples Include: Google (google.com), Yahoo! Search (yahoo.com), and Ask (ask.com).


Metasearchers

  • Searches multiple individual search engines

  • Presents results in one convenient list.

  • Good to use to get a feel for how much information is available on a topic.

    Examples include Dogpile (dogpile.com), Mamma (mamma.com), and Clusty (clusty.com).


Search strategy kickoff

  • Determine your needs:


Basic Search Techniques

  • Be specific

  • Put words in the order you would normally expect them to appear.

  • Avoid using common words.

  • Consider synonyms.

  • Use search focus options: (i.e. images, videos, or blogs).


Advanced Search Techniques

  • Boolean logic (AND, OR, NOT):

    • Boolean AND

      • Include all words.

      • Narrows your search.

    • Boolean OR

      • Include any of the words

      • Broadens your search.

      • Useful for synonyms.

    • Boolean NOT or AND NOT

      • Excludes words

      • Narrows your search


Advanced Search Techniques

  • Implied Boolean operators (+, -)

    • Used in place of the Boolean AND and Boolean NOT.

  • Phrase searching (“ “)

    • Place quotes around a phrase.

    • Returns documents where the words appear as a phrase (side by side).

  • Wildcards (*):

    • Used for plurals, alternative endings, or alternative spellings,


Advanced Search Techniques

  • Advanced search form

    • With all the words:Same as using the AND or plus (+) operator.

    • With at least one of the words: Same as using the OR operator.

    • With the exact phrase: Same as using quotes.

    • Without the words: Same as using the NOT or minus (-) operator.


Analyzing results

  • Scan through the first five to ten pages of results.

  • Consider synonyms.

  • Use the NOT or minus (-) operator.

  • Broaden your search.

  • Narrow your search.


Odds and Ends

  • Search engines ignore some pages.

    • dynamic (created on demand) such as a request for account information,

    • require registration or a login (like the Wor-Wic research databases).

  • database not always up-to-date.


Odds and Ends

  • Search within a site.

  • Search for individual words or phrases on a page

    • Edit > Find on this page…on the menu

    • Search List arrow,

      Find on this Page….


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