searching the web using search engines and directories effectively tutorial 4

Searching the Web

Using Search Engines and

Directories Effectively

Tutorial 4

Objectives

• Determine whether a research question is specific or exploratory.

• Learn how to formulate an effective Web search strategy to answer research questions.

• Learn how to use Web search engines, Web directories, and Web meta-search engines effectively.

Objectives

• Use Boolean logic and filtering techniques to improve your Web searches.

• Use advanced search options in Web search engines.

• Assess the validity and quality of Web research resources.

• Learn about the future of Web search tools.

Types of Search Questions

• A specific question is a question that you can phrase easily and one for which you will recognize the answer when you find it.

• An exploratory question is an open-ended question that can be harder to phrase; it is also difficult to determine when you find a good answer.

Specific Question

New Perspectives on the Internet, 5eTutorial 4

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Exploratory Question


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Web Search Process


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Web Search Strategy

• You may need to reformulate, or more clearly state, your question.

• Try to think of synonyms for each word.

• Identify unique phrases that relate to your topic or question.

Using Search Engines

Four Broad Categories Of Search Tools:

1. Search engines

2. Directories

3. Meta-search engines

4. Other Web resources such as Web bibliographies

Understanding Search Engines

• A web search engine is a Web site (or part of a Web site) that finds other Web pages that match a word or phrase you enter.

• The word or phrase you enter in a search engine is called a search expression or a query.

• A search expression or query might also include instructions that tell the search engine how to search.

• A search engine does not search the Web to find a match; it searches only its own database of information about Web pages that it has collected, indexed, and stored.


• A hit is a Web page that is indexed in the search engine’s database and that contains text that matches your search expression.

• Most search engines report the number of hits they find.

• All search engines provide a series of results pages, which are Web pages that contain hyperlinks to the Web pages that contain text that matches your search expression.


• A Web robot, also called a bot or a spider, is a program that automatically searches the Web to find new Web sites and update information about old Web sites that already are in the database.

• Most search engines allow Web page creators to submit the URLs of their pages to search engine databases.

• Search engine operators often sell advertising space on the search engine Web page and on the results pages.


• Some search engine operators sell paid placement rights on results pages. These paid placement links are often labeled as “sponsored,” and they are usually called sponsored links.

• If the advertising appears in a box on the page (usually at the top, but sometimes along the side or bottom of the page), it is usually called a banner ad.

• Revenue from sponsored links and banner ads is used to generate profit after covering the costs of maintaining the computer hardware and software required to search the Web and to create and search the database.



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HotBot search results for the search term “car”

Using More Than One Search Engine

• Each search engine includes different Web pages in its database.

• Different search engines use different rules to evaluate search expressions.

• The best way to determine how a specific search engine interprets search expressions is to read the Help pages on the search engine Web site.

• Search engines change the way they interpret search expressions from time to time, so you should read the Help pages regularly.

Understanding Search Engine Databases

• Search engine databases store different collections of information about the pages that exist on the Web at any given time.

• Each search engine database indexes the information it has collected from the Web differently.

• Search engine robots may collect information from a Web page’s title, description, keywords, HTML tags, or read a certain number of words from each Web page.


• A META tag is HTML code that a Web page creator places in the page header for the specific purpose of informing Web robots about the content of the page.

<HEAD>

<TITLE>Current Developments in Electronic Commerce</TITLE>

<META NAME ="description" CONTENT= "Current news and reports about electronic commerce developments.">

<META NAME ="keywords" CONTENT ="electronic commerce, electronic data interchange, value added reseller, EDI, VAR, secure socket layer, business on the internet">

</HEAD>

META tags in a Web page


• Full text indexing: when search engines store the entire content of every Web page they index.

• Stop words: common words, such as and, the, it, and by, that many search engines omit from their databases.

• Many search engines include information about their search engines, robots, and databases on their Help or About pages.

Search Engine Features

• Page ranking is a way of grading Web pages by the number of other Web pages that link to them. The URLs of Web pages with high rankings are presented first on the search results page.

• A natural language query interface allows users to enter a question exactly as they would ask a person that question.

• The procedure of converting a natural language question into a search expression is sometimes called parsing.

Search Engine Features


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Using Directories and HybridSearch Engine Directories

• A Web directory is a listing of hyperlinks to Web pages that is organized into hierarchical categories.

• The difference between a search engine and a Web directory is that people select the Web pages to include in a Web directory.

• Many directories allow a Web page to be indexed in several different categories.

• The main weakness of a directory is that you must know which category is likely to yield the information you desire.

• Yahoo! is one of the oldest and most respected directories on the Web.



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• The combination of search engine and directory is sometimes called a hybrid search engine directory.

• Using a hybrid search engine directory can help you identify which category in the directory is likely to contain the information you need.

• After you enter a category, the search engine is useful for narrowing a search even further. You can enter a search expression and limit the search to that category.

Using Meta-Search Engines

• A meta-search engine is a tool that combines the power of multiple search engines.

• Some meta-search tools also include directories.

• Because each search engine on the Web has different strengths and weaknesses, you might need to use several individual search engines to perform a complete search for a particular question.

• Using a meta-search engine lets you search several engines at the same time.

• Profusion, a popular meta-search engine, routes search terms to more than ten search engines and Web directories.

Using Meta-Search Engines


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Using Other Web Resources

• Other Web resources are similar to bibliographies in that they contain lists of hyperlinks to Web pages.

• Many of these resources include summaries or reviews of Web pages.

• They are often called Web bibliographies, but many other names are used for them:

• Resource lists• Subject guides• Clearinghouses• Virtual libraries

Using Other Web Resources

• Other web resources are sometimes confusingly called Web directories.

• Web bibliographies are usually more focused on specific subjects than Web directories, and Web bibliographies usually do not include a tool for searching within their categories.

• These other resources can be very useful when you want to obtain a broad overview or a basic understanding of a complex subject area.

• Some Web bibliographies are general references. Most are more focused. Many are created by librarians at university and public libraries.

Boolean Logic andFiltering Techniques

• The most important factor in obtaining good results in a Web search is careful selection of the search terms you use.

• You can usually choose one or two words that will work well when the object of your search is straightforward.

• More complex search questions require more complex queries, which you can use along with Boolean logic, search expression operators, or filtering techniques, to broaden or narrow your search expression.

Boolean Operators

• Boolean algebra was developed by George Boole, a nineteenth century British mathematician.

• Boolean operators, or logical operators, specify the logical relationship between the elements they join.

• Three basic Boolean operators—AND, OR, and NOT—are recognized by most search engines.

• You can use these operators in many search engines by including them with search terms.

Boolean Operators

Search Expression Search Returns Pages that Include

exports AND France AND Japan All of the three search terms

exports OR France OR Japan Any of the three search terms

exports NOT France NOT Japan Exports, but not if the page also includes the terms France or Japan

exports AND France NOT Japan Exports and France, but not Japan

Other Search Expression Operators

• A precedence operator, also called an inclusion operator or a grouping operator, clarifies the grouping within a complex expression and is usually indicated by the parentheses symbols.

• A location operator, or proximity operator, lets you search for terms that appear close to each other in the text of a Web page. The most common location operator offered in Web search engines is the NEAR operator.

Wildcard Characters

• Most search engines support some use of a wildcard character in their search expressions.

• A wildcard character allows you to omit part of a search term.

• Many search engines recognize the asterisk (*) as the wildcard character.

Search Filters

• Many search engines allow you to restrict your search by using search filters.

• A search filter eliminates Web pages from a search.

• The filter criteria can include such Web page attributes as language, data, domain, host, or page component.

Complex Searches

• Most search engines implement many of the operators and filtering techniques you have learned about.

• Some search engines provide separate advanced search pages for these techniques.

• Some search engines allow you to use advanced techniques such as Boolean operators on their simple search pages.

Using AltaVistaAdvanced Search

• Open the AltaVista search engine in your Web browser.

• Select the Advanced Search option.

• Formulate and enter a suitable search expression.

• Click the Find button.

• Evaluate the results and, if necessary, revise your search expression.

Using AltaVista Advanced Search


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Filtered Search in HotBot

• Open the HotBot search engine page in your Web browser.

• Select the HotBot Advanced Search link.


• Set any filters you want to use for the search.

• Click the SEARCH button.


Filtered Search in HotBot


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Filtered Search in Google

• Open the Google search engine page in your Web browser.

• Click the Advanced Search link.

• Formulate and enter suitable search expression elements.

• Formulate and set appropriate search filters.

• Click the Google Search button.


Filtered Search in Google


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Search Engines withClustering Features

• Vivísimo is a search engine that uses advanced technology to group its results into clusters.

• The clustering of results provides a filtering effect.

• The filtering is done automatically by the search engine after it runs the search.

Obtaining Clustered Search Results Using Vivísimo

• Open the Vivísimo search engine page in your browser.


• Click the Search button.


Obtaining Clustered Search Results Using Vivísimo


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Future of Web Search Tools

• A number of different companies and organizations are working on ways to make searching the Web easier.

• Work on natural language interfaces continues as search engine sites strive to make the job of searching even easier for users.

• An increasing number of search engines offer natural language querying as an option for entering search expressions.

Using People to EnhanceWeb Directories

• One company, About.com, hires people with expertise in specific subject areas to create and manage their Web directory entries in those areas.

• The Open Directory Project uses the services of more than 40,000 volunteer editors who maintain listings in their individual areas of interest.

• The Open Directory Project offers the information in its Web directory to other Web directories and search engines at no charge.

Evaluating the Validity and Quality of Web Research Resources

• Information on the Web is seldom subjected to the review and editing processes that have become a standard practice in print publishing.

• The risks of obtaining and relying on inaccurate or unreliable information can be significant.

• Reduce your risk by carefully evaluating the quality of any Web resource on which you plan to rely for information related to an important judgment or decision.

• Evaluate on the Web page’s authorship, content, and appearance.

Author Identity and Objectivity

• Web page should identify the author and present the author’s background information and credentials.

• Check secondary sources for corroborating information.

• Author contact information should be provided.

• Examine the domain identifier in the URL.

• Consider whether the qualifications presented by the author pertain to the material that appears on the Web site.

• Information about the author’s affiliations should be provided.

Content

• Determine timeliness of the content by checking the publication date.

• Read the content critically and evaluate whether the included topics are relevant to the research question at hand.

• Determine whether important topics or considerations were omitted.

• Assess the depth of treatment the author gives to subject.

Form and Appearance

• Many pages that contain low-quality or incorrect information are poorly designed and not well edited.

• A Web page that contains spelling errors indicates a low-quality resource.

• Loud colors, graphics that serve no purpose, and flashing text are all Web page design elements that often suggest low-quality resource.

Summary

• You learned how to formulate specific and exploratory research questions.

• You learned how to use a structured Web search process to find information on the Web.

• You learned how to develop search expressions and used them in search engines, Web directories, and meta-search engines.

Summary

• You learned what Boolean operators, precedence operators, and location operators are and how they work in several major search engines.

• You learned how to use wildcards in search expressions.

• You learned how to use several types of filtering techniques to narrow your search results.

Summary

• You learned how to evaluate the validity and reliability of a Web page by using information about author identity and objectivity.

• You learned how to evaluate the validity and reliability of a Web page by evaluating content, form and appearance.

searching the web using search engines and directories effectively tutorial 4

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