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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 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….