Transcript Class Powerpoint

Word of the Day
URL
Uniform resource locator – or Web
address, unique to every web page
www.carpeindexum.com/libs100mw/sum05.htm
Searching and Boolean
Operators
LIBS100
June 8, 2005
Web browsers:
Computer software that allows you to
view WWW documents
– Internet Explorer (Microsoft)
– Netscape Navigator/Communicator
– Firefox
review
Structure of the Web
• The Internet : a network of networks;
computers linked together that communicate
by a shared protocol (TCP/IP)
• World Wide Web : data files (e.g., documents,
images, videos, etc.) residing on Internet
information servers (computers); mainly use
HTTP protocol to transfer data
Browser Basics
• Address Bar- where you can input URL
• Go – takes you to address you input
• Home icon – pressing this takes you to
your home page
Browser Basics
• Back – takes you back one page
• Forward – brings you forward one page
• Search bar – where you can input
search terms
Internet
• Exciting place to do research
• Often the first place people turn
• Overwhelmingly huge
– WWW contains “tens of billions” of pages
• Google indexes largest number of pages
– Reports over 8 billion pages indexed
Google
• Largest search engine
• Crawler-based
– Uses software called “crawlers” or “spiders”
to automatically search through web pages
and follows links
• Highly relevant results
Google
• Created in 1998 by 2 Stanford students
• Google is exclusively a search engine
• Elegantly simple, easy to use
What is a Relevant Result??
A hit that meets your informational
need
• “Bad results” due to:
– Poorly constructed queries
– Bad relevance ranking by search engines
– Poorly constructed queries
How does Google rank web
pages??
• Location/frequency
– The location of search terms on the web
page
– How many times search terms appeared
• Link popularity (Google PageRank) number of pages that link TO Page X
boosts Page X’s ranking
• Penalties for artificially inflating results
Google Searches
• Automatically adds AND between your
terms
• Ignores “stop words” the, and, of, to…
• Can use other words to broaden or
narrow search results
Boolean Operators
Boolean Logic
• George Boole (1815-1864) –
Mathemetician who discovered that
logical reasoning can be represented in
terms of mathematical formulas
• Boolean Algebra – Only two conditions
allowed 1=True or 0=False
• Boolean Query – Search terms joined
by AND, OR, NOT
Boolean Operators
• AND – locates records containing both
terms.
• OR – locates records containing either
term
• NOT – locates records containing first
term, but not the second
• In Google (and most other search
engines) the operators MUST be
capitalized
Boolean Machine
http://kathyschrock.net/rbs3k/boolean/
Which query will give us the
most hits?
endangered (AND) birds
endangered OR birds
endangered NOT birds
birds NOT endangered
Boolean Math
•AND use the + sign
•NOT use the – sign
• “Multiplier” enclose phrase in
quotes
No space between search terms and sign!
Modifying Searches
• Based on results list, modify your
search string to get better results
• Add, delete or change terms used
• Use “quotation marks” to search for a
phrase
Work for Monday
• Tyner, Ross. “Choosing and Developing a Topic.”
Okanagan University College 31 Jan 2004. 3 May
2005
http://www.ouc.bc.ca/library/eil/research/topic.html .
• Quiz moved to Wednesday, June 15th
References
• Rothenberger, Michelle. “Search Engines.” Accessed 6
Feb 2005
http://www.carpeindexum.com/libs100/srcheng/srchdir.ppt
• Staff. “Resources, INFS100.” Minneapolis Community
and Technical College. Accessed 6 Feb 2005
• Sullivan, Danny. “Search Features Chart.”
Searchenginewatch.com 26 Oct 2001. Accessed 6 Feb
2005
http://searchenginewatch.com/facts/article.php/2155981