Transcript search expression - E

Chapter 4: Using S.E. &
Directories Effectively
Prepared by: Ms Melinda Chung
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 S.E., Web directories,
and Web meta-S.E. effectively.
Objectives

Use Boolean logic and filtering techniques to
improve your Web searches.

Use advanced search options in Web S.E..

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 is harder to phrase; also difficult
to determine when you find a good answer.
Specific Question
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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 S.E.
Four Broad Categories Of Search Tools:
•
S.E.
•
Directories
•
Meta-S.E.
•
Other Web resources such as Web
bibliographies
Understanding S.E. (S.E.)

A web S.E. is a Web site/part of a Web site that finds
other Web pages that match a word/phrase you enter.

A search expression/query - is the word or phrase
you enter in a S.E.

A search expression/query - can include instructions
telling the S.E. how to search.

A S.E. 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.
Understanding S.E.

A hit is a Web page that is indexed in the
S.E.’s database and that contains text that
matches your search expression.

Most S.E. report the number of hits they find.

All S.E. 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.
Understanding S.E.

A Web robot (bot/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 S.E. allow Web page creators to submit
the URLs of their pages to S.E. databases.

S.E. operators often sell advertising space on
the S.E. Web page and on the results pages.
Understanding S.E.

Some S.E. operators sell paid placement rights on results
pages. These paid placement links are often labeled as
“sponsored,” and are called sponsored links.

A banner ad. - advertisement appears in a box on the page
(usually at the top, but can be at the side or bottom of the
page),

Revenue from sponsored links and banner ads is used to
generate profit after covering the costs of maintaining the
computer h/w and s/w required to search the Web and
creation & maintenance of the database.
Understanding S.E.
HotBot search
results for the
search term “car”
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Using More Than One
S.E.

Each S.E. includes different Web pages in its
database.

Different S.E. use different rules to evaluate search
expressions.

The best way to determine how a specific S.E.
interprets search expressions is to read the Help
pages on the S.E. Web site.

S.E. change the way they interpret search
expressions from time to time, so you should read
the Help pages regularly.
Understanding S.E. Databases

S.E. databases store different collections of
information about the pages that exist on the
Web at any given time.

Each S.E. database indexes the information it
has collected from the Web differently.

S.E. 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.
Understanding S.E. Databases

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.
META tags in a Web 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>
Understanding S.E. Databases

Full text indexing: when S.E. store the entire
content of every Web page they index.

Stop words: common words, such as and,
the, it, and by, that many S.E. omit from their
databases.

Many S.E. include information about their
S.E., robots, and databases on their Help or
About pages.
S.E. Features

Page ranking: 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.

Parsing: the procedure of converting a natural
language question into a search expression.
S.E. Features
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Using Directories and Hybrid
S.E. Directories

A Web directory: a listing of hyperlinks to Web pages
that is organized into hierarchical categories.

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.
Using Directories and Hybrid
S.E. Directories
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Using Directories and Hybrid
S.E. Directories

A hybrid S.E. directory: a combination of S.E.
and directory.

A hybrid S.E. directory helps you identify
which category in the directory is likely to
contain the information you need.

After you enter a category, the S.E. is useful
for narrowing a search even further. You can
enter a search expression and limit the search
to that category.
Using Meta-S.E.

A mega-S.E. - a tool that combines the power of multiple S.E.

Some meta-search tools also include directories.

Using a meta-S.E. lets you search several engines at the
same time.

Profusion, Dogpile, ixquick - popular meta-S.E.

Effective search - use several individual S.E. to perform a
complete search for a particular interest.
Using Meta-S.E.
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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, such as:




Resource lists
Subject guides
Clearinghouses
Virtual libraries
Using Other Web Resources

Web bibliographies - more focused on specific
subjects than Web directories, usually do not
include a tool for searching within their categories.

Are useful when you want to obtain a broad
overview or a basic understanding of a complex
subject area.

Some are general references. Many are created by
librarians at university and public libraries.
Boolean Logic and
Filtering Techniques

The most important factor in obtaining good results careful selection of the search terms used.

Straightforward search object - choose one or two
words.

Complex search questions/queries - use Boolean
logic, search expression operators, or filtering
techniques, to broaden or narrow your search
expression.
Boolean Operators

Boolean algebra - developed by George Boole, a
nineteenth century British mathematician.

Boolean operators/logical operators - specify the
logical relationship between the elements they join.

Three basic Boolean operators—AND, OR, and
NOT—are recognized by most S.E..

Operators can be included 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
exports AND France NOT Japan
includes the terms France or Japan
Exports and France, but not Japan
Other Search
Expression Operators

A precedence operator (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/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 S.E. is the NEAR operator.
Wildcard Characters

Most S.E. support some use of a wildcard
character in their search expressions.

A wildcard character allows you to omit part
of a search term.

Many S.E. recognize the asterisk (*) as the
wildcard character.
Search Filters

Many S.E. 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 S.E. implement many of the operators
and filtering techniques.

Separate advanced search pages for these
techniques - Google.com.

Some S.E. allow advanced techniques such
as Boolean operators on their simple search
pages.
Using AltaVista
Advanced Search

Open the AltaVista S.E. in your Web browser.

Select the Advanced Search option.

Formulate & enter a suitable search expression.

Click the Find button.

Evaluate the results, if necessary, revise your search
expression.
Using AltaVista Advanced
Search
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Filtered Search in HotBot

Open the HotBot S.E. page in your Web
browser.

Select the HotBot Advanced Search link.

Formulate and enter a suitable search
expression.

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 S.E. 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.

Evaluate the results and, if necessary, revise your search
expression.
Filtered Search in Google
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S.E. with
Clustering Features

Vivísimo is a S.E. 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 S.E.
after it runs the search.
Obtaining Clustered Search
Results Using Vivísimo

Open the Vivísimo S.E. page in your browser.

Formulate and enter a suitable search
expression.

Click the Search button.

Evaluate the results and, if necessary, revise
your search expression.
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
S.E. sites strive to make the job of searching even
easier for users.

An increasing number of S.E. offer natural
language querying as an option for entering
search expressions.
Evaluating the Validity & 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.

Reduce your risk by carefully evaluating the quality
of any Web resource on which you plan to rely for
information.

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.

Are the qualifications of author available?

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.

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 S.E., Web
directories, and meta-S.E..
Summary

You learned what Boolean operators,
precedence operators, and location operators
are and how they work in several major S.E..

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.