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SEARCHING FOR TRUTH

Locating Information on the WWW

chapter5

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Characteristics of Directories

• Topical lists of Internet Resources• arranged in a hierarchical way• differ from search engines: humans maintain

directories and search engines rely on spiders or robots to crawl the Internet for links.

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Characteristics of Directory

• Ask the following questions:– Who selects the included Web resources?– Who categorizes the Web pages and sites?– How are the results displayed?– Are the sources rated? annotated? reviewed?

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Strengths of Directories

• fewer resources than search engine databases

• provide rating or annotation of resources• increase probability of finding relevant results

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Disadvantages

• arbitrary hierarchical arrangements• infrequent updates• subjectivity of rating and annotating

resources

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Using the Yahoo Directory

• Go to Yahoo• click on Science• follow appropriate links to Human Genome

Projects.

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Using Directory Search

• Go to Yahoo home page• click on search and enter “Human genome

project”

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The First Step: Evaluating Your Information Needs

• Types of information most likely to be found on the Internet

• Some reasons why the Web won’t have everything you’re looking for

• Choosing the best tool to start with• A checklist to help you choose the right tool

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Finding Information Gems in Virtual Libraries

• Virtual libraries are directories that contain collections of evaluated resources that have carefully selected by information specialists.

• Subject guides, reference works, and specialized databases, are most likely found in virtual libraries.

• Two popular virtual libraries are the Internet Public Library, http://ipl.org, and the Librarians’ Index to the Internet, http://lii.org.

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Searching the World Wide Web: Using Search Engines

• Search engines use computer programs called spiders or robots to gather information on the Internet.

• The information is kept in a database that is searchable.

• Two popular search engines are Google, http://www.google.com, and AltaVista, http://altavista.com.

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Search Engine Similarities

• Search engines list results by some type of relevancy ranking scheme.

• Two common search features are Boolean searching and phrase searching.

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Search Engine Differences

• Size of the database• Search options• Update frequency• Ranking of search results• Special features (images, news, and so forth)

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Using Several Search Engines Simultaneously: Meta-search Tools

• Some allow you to search several search engines simultaneously.

• Some supply lists of databases that can be searched directly from their pages.

• May provide a good way to keep up with new search engines.

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Task

• Explore the Directory of NPR – describe its organization

• Now look at a web library. Describe its organization

• Find the Kelly book value of my car: a 1998 Honda Civic CX.

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Content Issues: Pornography, Free Speech, Censorship, and Filtering

• Free speech vs. censorship• Communications Decency Act of 1996• Filtering and blocking devices

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UW libraries Top 20 Databases with links

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Summary links for UW libraries reference materials

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Top level, second level and third level classifications of a collection

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National Public Radio (NPR) home page www.npr.org

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The NPR home page Programming pull-down menu

What are the top level

classifications?

What are the top level

classifications?

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The NPR programming hierarchy tree

How many levels in the hierarchy?

How many levels in the hierarchy?

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The Google search engine’s advanced search view

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Restricting the Thai restaurants “hits” by eliminating any page containing the word review.

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Making Effective Queries

• Queries use the three logical operatorsworda AND wordb -- both words must appear

worda OR wordb -- either word may appear

NOT worda -- the word is prohibited from appearing

• Google has separate windows for each• When 1 window is available, write a formula

(Lincoln OR Jefferson) AND NOT Memorial

worda wordb

Which parts of the diagram do the operators

cover?

Which parts of the diagram do the operators

cover?

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The Burmese mountain dog page

Does this page seem

legitimate?

Does this page seem

legitimate?