Transcript - SCT Web Site - Eastern Mediterranean University

Eastern Mediterranean University
School of Computing and Technology
Department of Information Technology
ITEC229
Client-Side Internet and Web Programming
Searching the Web
CHAPTER 2
Prepared by: R. Kansoy
LOGO
Contents
2.1 Searching the Web
2.2 Search Engines
2.3 Searching Techniques
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2.1 Searching the Web
 If you don't know which site to go to for the information
you're looking for you are going to have to search the Web.
 The Web is a worldwide resource of information.
 A primary reason that people use the Web is to search for
specific information, including text, pictures, music, and
video.
 There are many free services you can use to find
information on the Web;
 Search Engines, Search Directories, and Meta Search
Engine
 Some Web sites offer the functionality of both a search
engine and a subject directory.
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2.1 Searching the Web
 Search engines constantly visit Web sites in order to
catalog Web pages.
 Directories are created by humans who assign submitted
sites to an appropriate category or categories, such as
sports or shopping, and related subcategories.
 Meta search engines are search tools that search several
search engines at once.
 Examples: Search Directory – Yahoo, Search Engine –
AltaVista, Meta Search Engine - Mamma.
 You can browse through categories, such as arts or sports,
to find information that interests you or you can search for
a specific word or topic.
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2.1 Searching the Web
Limitations of Internet Research
 Information Available
 Amount of Time
 Quality of Information
 There are limitations of using the Internet as a research tool.
People often have the misconception that the Internet contains
every bit of knowledge...every piece of information ever written,
and that all they have to do is type in their subject and they'll be
able to pull up exactly what they were looking for.
 The Internet doesn't contain every piece of information ever
written and probably never will. There have been millions if not
billions of books and articles published over time and only a
fraction of the information contained within them is on the
Internet. The information doesn't magically appear, someone has
to put it on the Internet.
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2.1 Searching the Web
 In addition, searching for information on the Internet often
takes a great deal of time if you don't know of a site that
contains the information.
 Depending on your subject and which search engine you
use, you may pull up several thousand web pages. And you
may look through all of the pages, which could take hours,
and even then you may not find what you’re looking for. On
the other hand, you can sometimes find a great site with
the information you need in only a few minutes.
 Also keep in mind that since no one controls the Internet,
anyone can put information on it. Some of that information
may be useful and some of it be garbage and useless as a
source for research.
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2.2 Search Engines
 A search engine is a program that finds Web sites, Web
pages, documments, images, videos, news, maps, and
other information related to a specific topic.
 A search engine is helpful in locating information for
which you do not know an exact Web address or are not
seeking a particular Web site.
 Are like the index in the back of a book
 Search engines require that you enter a word or phrase,
called search text or search query, that describes the
item you want to find.
 Each word in the search text is known as a keyword.
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2.2 Search Engines
 Thousands of search engines are available.
 Some search through Web pages for all types of information.
 Other search engines can restrict their searches to a specific type
of information, such as the following items:
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Images
pictures, diagrams, and drawings.
Videos
home videos, music videos, television
programs, and movie clips.
Audio
music, songs, recordings, and sounds.
Publications
news articles, journals, and books.
Maps
maps of a business or address, or driving
directions to a destination.
People or Businesses
addresses and telephone numbers.
Blogs
specific opinions and ideas of others.
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2.2 Search Engines
 Pros
 Large chunk of publicly available web
 Best way to search for specific info on the web
 Cons
 Too much info!!
 Too many irrelevant hits
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2.2 Search Engines
 How do they work?
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Crawl the web with “spider” or “bots”
Travels from link to link
Collects information on publicly available pages
Creates an index of all these sites
Matches the search terms you enter to the index
Presents the search with the results list, or “hits”
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2.3 Searching Techniques
How to Search?
Well-prepared searches will eliminate useless hits and wasted time.
learn how to use a search engine properly to limit the search results to
find only the information which is really relevant.
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What do you need to know about your topic?
Make a list of all the terms connected with your topic.
Include names, organizations, and phrases.
Make a list of the words that are critical to your search.
Note terms that you don’t want to see appear.
Discard the rest.
If you are doing serious research on a specific topic, advanced
searching is a better option.
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2.3 Searching Techniques
Search Engine Operators
Operator
AND, +
OR
NOT, -
()
*
““
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Description
Examples
Explanation
Display hits that include specific
words
art + music
Results have both words art and
music — in any order.
Display hits that include only one
word from a list.
dog OR puppy
Results have either the word dog
or puppy.
Exclude a word from the search
results.
automobile
-convertible
Results include automobile but do
not include convertible.
Combine hits that include
specific
words with those that include
only
one word from a list.
Kalamazoo
Michigan
(pizza OR subs)
Results have both words
Kalamazoo Michigan and either
the word, pizza, or the word,
subs.
Substitute characters in place of
the asterisk.
writer*
Results include any word that
begins with writer
(e.g., writer, writers, writer’s).
Search for an exact phrase in a
certain order.
“19th century
literature”
Results have the exact phrase,
19th century literature.
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2.3 Searching Techniques
 Other techniques you can use to improve your searches
include the following:
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Use specific nouns.
Put the most important terms first in the search text.
List all possible spellings, for example, email, e-mail.
Before using a search engine, read its Help information.
If the search is unsuccessful with one search engine, try
another.
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Searching the Web
END of CHAPTER 2
LOGO
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