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Library 102 Second Class Session
According to Randolph Hock, the author of The Extreme Searcher's Handbook, the strengths and weaknesses of general web directories are as follows:
The three main points to remember about web directories are that they are selective, that is, selected by persons according to some set standards of quality, although some directories allow paid inclusion. Secondly, they are categorized (classified) by broad topics and sub-topics. This hierarchical arrangement helps to narrow a broad topic. Thirdly, usually only the homepage or main page of the site is indexed, which contrasts with search engines where every page of the web site is usually indexed. For more than two concepts, it is generally better to use a search engine. The University of California at Berkeley Library sponsors an excellent tutorial and table of features for recommended subject directories. Although they may appear to be normal web sites,
Proprietary Databases are not. Proprietary means exclusively
owned, private. If you have access to searching one of these databases, it is
because someone has paid for that privilege. These databases are not searched by
web search engines and, therefore, their information does not show up in normal
web search results. These databases make up part of what is referred to as
The Invisible or Deep Web. The proprietary databases that are available to COS students
are linked to the COS Library Web Page under the category: Academic
Electronic Databases. The link is:
Proprietary Databases are one part of the
invisible web (invisible to search engines). Usually these databases require a paid subscription.
Sometimes the site may be password-protected for members only of an
organization; sometimes the site may offer free searching but registration
is required; often newspaper sites require registration.
The Library site at the University of California at Berkeley offers a more in depth discussion of the Invisible Web: http://www.lib.berkeley.edu/TeachingLib/Guides/Internet/InvisibleWeb.html .
_________________________________________________________________________________ Clyde, Anne. "The Invisible Web" Teacher Librarian. April
2002. There is not just one right or wrong way to search the Web, but because the Web is so vast, it is important to find an efficient way to search. That is why a search strategy is important. Some components of a search strategy are as follows: 1. Try to formulate what you are looking for in a complete sentence and identify the key concepts or words in that sentence. 2. Identify concepts or terms that can be searched as a phrase and words that may have synonyms or terms that may need to be more specific. 3. Do a preliminary search and examine your first results. Decide if you need to narrow or broaden your terms and keep examining your results until you find what you want. 4. Use Boolean connectors or advanced search options to refine your search. There are three main characteristics of search engines. First, they index billions of sites whereas directories usually index millions or thousands. Secondly, they are created by indexing software rather than by human selection. Thirdly, they function best when the search query is specific; they are not very effective for browsing. A search engine works first by "crawling" the web for new sites
or sites that have changed. Crawlers are also referred to as "spiders". Each search engine indexes only a fraction of the web. The sites indexed will vary from one search engine to another, so you may need to try your search in more than one engine. At the time of your search, the search engine is retrieving sites from its index, not the actual page; as a result, there could be pages retrieved that no longer exist. Typical search engine search options are by phrase, title, URl, site, domain, language, date, file type, and Boolean operators. These engines have a specific focus: Scirus
- distinguishes itself from existing search engines by
concentrating on scientific content only and by searching both web and journal
sources. It enables scientists, students and anyone searching for scientific
information to chart and pinpoint data, locate university sites, and find
reports and articles in a clutter-free, user-friendly and efficient manner. A link for finding specialized search engines: http://dmoz.org/Computers/Internet/Searching/Search_Engines/Specialized/ Meta Search EnginesUnlike search engines, meta search engines do not compile their own databases; they send the search simultaneously to the major search engines and return the results from several different search engines. Because meta search engines tend to equalize the search to the lowest common denominator, they are best used for simple searches. Very complex search logic or searches with several words will usually not produce good results in a meta search engine. Also meta search engines usually only retrieve about 10% of any of the results in any one of the search engine databases.1 Although the University of California at Berkeley Library has created a table of features for meta search engines, UC Berkeley's library does not recommend using meta search engines. This is the link to this table: http://www.lib.berkeley.edu/TeachingLib/Guides/Internet/MetaSearch.html#Recommend ________________________________________________________________________________________
1 Barker, Joe,
"Meta-Search Engines," Finding Information on the Internet: A TUTORIAL,
10 May 2000,
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