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WEB   SEARCH.

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Presentation on theme: "WEB   SEARCH."— Presentation transcript:

1 WEB   SEARCH

2 WEB    SEARCH    STRATEGIES Because the Web is not indexed in any standard manner, finding information can seem difficult. Search engines are popular tools for locating web pages, but they often return thousands of results. So you need to know clear search strategy, using a search engine.

3   WEB    SEARCH    STRATEGIES Successful searching involves two key steps: ·        First, you must have a clear understanding of how to prepare your search. You must identify the main concepts in your topic and determine any synonyms, alternate spellings, or variant word forms for the concepts. ·        Second, you need to know how to use the various search tools available on the Internet. For example, search engines (e.g., AltaVista) are very different than subject directories (e.g., Yahoo). Even search engines themselves can vary greatly in size, accuracy, features, and flexibility.

4 SUBJECT   DIRECTORIES   A subject directory is a catalog of sites collected and organized by humans. Subject directories are often called subject "trees" because they start with a few main categories and then branch out into subcategories, topics, and subtopics.

5 SEARCH   ENGINES   Search engines are very different from subject directories. While humans organize and catalog subject directories, search engines rely on computer programs called spiders or robots to crawl the Web and log the words on each page. With a search engine, keywords related to a topic are typed into a search "box." The search engine scans its database and returns a file with links to websites containing the word or words specified. Because these databases are very large, search engines often return thousands of results.

6 SEARCH   ENGINES   To use search engines effectively, it is essential to apply techniques that narrow results and push the most relevant pages to the top of the results list. Let’s practice the search technique with AltaVista's search engine.

7 IDENTIFY  KEYWORDS When conducting a search, break down the topic into key concepts. For example, to find information on what the FCC has said about the wireless communications industry, the keywords might be: FCC   wireless   communication

8 BOOLEAN  AND Connecting search terms with AND tells the search engine to retrieve web pages containing ALL the keywords. FCC   and   wireless   and   communication In this case the search engine will only return pages where the words FCC, wireless, and communication all appear somewhere on the page. Thus, AND helps to narrow your search results as it limits results to pages where all the keywords appear.

9 BOOLEAN  OR Linking search terms with OR tells the search engine to retrieve web pages containing ANY and ALL keywords. (FCC  or  wireless  or  communication) When OR is used, the search engine returns pages with a single keyword, several keywords, and all keywords.

10 BOOLEAN  AND  NOT AND NOT tells the search engine to retrieve web pages containing one keyword but not the other. dolphins   and  not   Miami The above example instructs the search engine to return web pages about dolphins but not web pages about the "Miami Dolphins" football team.

11 IMPLIED BOOLEAN: PLUS & MINUS
In many search engines, the plus and minus symbols can be used as alternatives to full Boolean AND and AND NOT. The plus sign (+) is the equivalent of AND, and the minus sign (-) is the equivalent of AND NOT. There is no space between the plus or minus sign and the keyword. +welding   +process +Saturn   -car

12 "John F. Kennedy" "Walt Disney World" "global warming"
PHRASE  SEARCHING Surrounding a group of words with double quotes tells the search engine to only retrieve documents in which those words appear side-by-side. Phrase searching is a powerful search technique for significantly narrowing your search results, and it should be used as often as possible. "John F. Kennedy" "Walt Disney World" "global warming"

13 title:"George Washington"+President+Martha
TITLE  SEARCH Field searching is one of the most effective techniques for narrowing results and getting the most relevant websites listed at the top of the results page. A web page is composed of a number of fields, such as title, domain, host, URL, and link. Searching effectiveness increases as you combine field searches with phrase searches and Boolean logic. For example, if you wanted to find information about George Washington and his wife Martha, you could try the following search:  title:"George Washington"+President+Martha

14 DOMAIN  SEARCH The DOMAIN (or site) SEARCH allows you to limit results to certain domains such as websites from the United Kingdom (.uk), educational institutions (.edu), or government sites (.gov). domain:uk   and   title:"Queen Elizabeth"   +domain:edu   +"lung cancer"   +smok*

15 +host:www.disney.com+"special offer"
HOST  SEARCH The HOST SEARCH comes in handy when you need to find something located at a large site that does not have an internal search engine. With this search technique, you can search all the pages at a website (contained in the engine's database) for keywords or phrases of interest. +host: offer"

16 +url:halloween+title:stories url:halloween and title:stories
URL  SEARCH The URL SEARCH limits search results to web pages where the keyword appears in the URL or website address. A URL search can narrow very broad results to web pages devoted to the keyword topic. +url:halloween+title:stories url:halloween   and   title:stories

17 PREPARING    YOUR    SEARCH By spending a few minutes clarifying your search, you can increase your chances of finding what you need fast and effectively. STEP  1:   STATE  WHAT  YOU  WANT  TO  FIND First, in one or two sentences, state what you want to find on the Internet. For example: I want to find information on popular methods of losing weight. What are the characteristics to look for when purchasing a diamond?

18 PREPARING YOUR SEARCH STEP 2: IDENTIFY KEYWORDS
Next, underline the main concepts in the statement. I want to find information on popular methods of losing weight. What are the characteristics to look for when purchasing a diamond?

19 PREPARING YOUR SEARCH STEP 3: SELECT SYNONYMS AND VARIANT WORD FORMS
List synonyms, alternate spellings, and variant word forms of each keyword. popular    common    favorite methods    method    ways    way    techniques    technique losing    lose    reducing    reduce    reduction weight    fat    dieting    diet

20 PREPARING    YOUR    SEARCH STEP  4:   COMBINE  SYNONYMS,  KEYWORDS, AND  VARIANT  WORD  FORMS Combine synonyms with Boolean OR. NOTE: Place parentheses around OR statements. (popular or common or favorite) (methods or method or ways or way or techniques or technique) (losing or lose or reducing or reduce or reduction) (weight or fat or dieting or diet)

21 Use truncation with an asterisk symbol (
Use truncation with an asterisk symbol (*) to combine variant word forms. (popular or common or favorite) (method* or way* or technique*) (los* or reduc*) (weight or fat or diet*)

22 Combine keywords with Boolean AND.
(popular or common or favorite) and (method* or way* or technique*) and (los* or reduc*) and (weight or fat or diet*)

23 PREPARING YOUR SEARCH STEP 5: CHECK YOUR SPELLING
Search engines return websites with words that match your keywords. If you misspell a keyword, your results will contain websites where that word is also misspelled.

24 META- SEARCH   ENGINES   Meta-search engines (also know as multi-threaded engines) search several major engines at once. Meta-search engines do not crawl the Web or maintain a database of web pages. Instead, they act as a middle agent, passing on the query to the major engines and then returning the results.

25 (rules+and+card+and+game+and+bridge)
META- SEARCH   ENGINES   Because the major search engines often produce very different results, meta-search engines provide a quick way to determine which engines are retrieving the best match for your information need. Because search engines vary in ability to interpret complex searches, meta-search engines work best with simple searches. Example for Dogpile ( : (rules+and+card+and+game+and+bridge)

26 SPECIALTY   DATABASES   Sometimes a specialty database will be more effective at finding what you need than a general search engine. Specialty databases are dedicated to collecting relevant sites for a particular subject. Example: At Search.com Click on the research by topic link below the search box. In the Reference category, click on Recipes. Type pumpkin pie in the search box. Click the Search button. Review the results. Click any links of interest.

27 PRACTICE   EXERCISE 1.  What U.S. President was born in a town named Caldwell?    Search: (+President +Caldwell +born) 2.  What are the two species of elephants?    Search: +title:elephant* +two +species 4.  From what place did the Ebola virus get its name?    Search +title:Ebola +virus +name* 5.  What is the address of the Empire State Building?    Search title:"Empire State Building" 6.  What is North Carolina's state bird?    Search +"North Carolina" +"state bird" 7.  Who invented the paper clip?    Search +invent* +"paper clip" 8.   What country had the largest recorded earthquake?    Search +title:earthquake +largest +recorded


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