Matakuliah
Tahun
Versi
: M0284/Teknologi & Infrastruktur E-Business
: 2005
: <<versi/revisi>>
Pertemuan 20
Searching Mechanisms
1
Learning Objectives
• Describe the role of search engines in ebusiness
• Explain how search engines work
• Describe use of search engines in intranet and
extranet environment
• Identify important search engines in the market
• Describe a flexible search strategy
2
Directories and Databases
• Searchable subject/ topic directory
yahoo.com
– A hierarchy of topics entries are submitted
to the site, verified and included in the
directory. Good quality control
• Virtual Libraries
http://sunsite.berkely.edu/internetindex
• Specialized databases both content and
index
– Lexis-Nexis, Medline, Dialog
3
Meta-Search Engines
•Coordinate the services of several searchengines
•Dogpile
www.dogpile.com
•Metacrawler www.metacrawler.com
4
Search Engine Evaluation
• Recall
– Ratio of pages returned to total volume of
pages on the world wide web
• Precision
– Ratio of pages returned that are relevant
• Conflicting nature of the above two criteria
5
Search Engine Evaluation
• Directories like Yahoo are high in
precision, poor in recall
• General sites such as Altavista are high in
recall and poor in precision
• Design challenge in search engine is to
have both high precision and recall
6
Search Engine Evaluation
• Search life cycle
– Initial phase exploration phase high recall
is required
– Later phase exploitation phase high
precision is required
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Popular Search Engines
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Google
Yahoo
Altavista
Northern Light
Lycos
Excite
8
Flexible Search Strategy
• Determine specificity of search required
– In exploration or exploitation phase?
• Choose a search engine that suits the
specificity of search
– meta-search engines for initial phase of
exploration
• Build a search query
– Boolean statements
9
A Search Example
• How to develop a small business in the
engineering area and obtain a prospective
list of customers
– Start with a virtual library
10
A Search Example
11
A Search Example
Response to query “small business”
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A Search Example
• A site on small business
13
A Search Example
• Business Week Site on Small Business
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