contents
DESCRIPTION
Contents. Boolean Logic Truncation Phrase Searching. the THEORY. Boolean Logic. Boolean logic allows users to combine search terms. Boolean logic allows users to both expand or limit their search. the THEORY. Boolean Logic. - PowerPoint PPT PresentationTRANSCRIPT
Contents
•Boolean Logic
•Truncation
•Phrase Searching
theTHEORY Boolean Logic
• Boolean logic allows users to combine search terms.
• Boolean logic allows users to both expand or limit their search.
• This is achieved by using Boolean operators AND, OR and NOT to link the search terms in searches.
• Boolean logic is used by search engines on the Internet and some CD ROMs.
Boolean Logicthe
THEORY
• An example will explain how the operators (or link words) work to limit or expand your search.
• The question for this search is:
How are children affected by television?
Boolean Logicthe
THEORY
• First it is necessary to isolate the major terms from the example to use as search terms.
• These terms are referred to as key words.
• E.g. The keywords from this example are CHILDREN and TELEVISION.
Boolean Logicthe
THEORY
• The first operator (or link word) to investigate is OR
• How will it affect the search on children and television?
• Will the search expand or will OR limit the search?
Boolean Logicthe
THEORY
• Type in “children OR television”
• Documents retrieved have either of the key words on them.
Boolean LogicUsing
OR
ORHighestretrieval
Television & children
• The second operator (or link word) to investigate is AND
• How will it affect the search on CHILDREN and TELEVISION
Boolean LogicUsingAND
• Type in “children AND television”• Items retrieved only where children
and television both appear on the pages.
Boolean LogicUsingAND
Television & children
ANDnarrows the
search
• The third operator (or link word) to investigate is NOT
• How will it affect the search on CHILDREN and TELEVISION?
Boolean LogicUsingNOT
• Type in “television NOT children”• Items retrieved refer to television
only.
Boolean LogicUsingNOT
Items on
television
NotPages contain
one but not
the other term
• Search engines require users to click on advanced search to use boolean searching.
• Individual engines use boolean slightly differently.
• The example of how Alta Vista uses boolean logic will explain further.
Boolean LogicUsing
ALTA VISTA
• Boolean searching with search engine Alta Vista requires the + (plus) symbol to be placed before all terms if they are to be included. (+ replaces AND)
• E.g. +china +platewill result in both terms being somewhere in all documents retrieved.
Boolean LogicUsing
ALTA VISTA
Try it : http://www.altavista.com/
• Boolean search with Alta Vista requires the – (minus) symbol to be placed before terms which are to be excluded. (- replaces NOT)
• E.g. china –plates retrieves all documents with China but excludes documents containing plates.
Boolean LogicUsing
ALTA VISTA
Try it : http://www.altavista.com/
• Truncation is a tool which can broaden a search.
• Users enter part of a word in order to ensure retrieval of all documents containing variations of the word.
• Try the next examples using Alta Vista.
TruncationUsing
ALTA VISTA
• Tool to broaden searches1.Right hand truncation with*• Type sight*• You will retrieve documents with
sights, sightseeing, sighted etc.
Try it: http://www.altavista.com/
TruncationUsing
ALTA VISTA
2. Internal “wild-card” truncation with*
• Type colo*r
• You will retrieve documents containing both colour and color.
• Try it: http://www.altavista.com/
TruncationUsing
ALTA VISTA
• Phrase searching offers another tool which will contribute to a successful search on the Internet.
• Try the following examples -
Phrase SearchingUsing
• Enclose terms to be searched as a phrase in quotes
“children’s book week”“The capital city of India”
• The phrase will be retrieved exactly as keyed in.Try it: http://www.google.com/
Phrase SearchingUsing
References
•Henninger, M. (1999). Don’t Just Surf. Effective research strategies for the net. University of New South Wales Press Ltd., Sydney.
Tyner, R. (1999). Internet Search Tools & Techniques. M.L.S.Okanagan University College. Available from http://www.sci.ouc.bc.ca/libr/connect96/search.htm
Barlow, L.(1996-1999). The Spider’s Apprentice: A Helpful Guide to Search Engines. Monash Information Services. Available from: http://www.monash.com/spidap4.html
Created & Designed by
Syba Signs P/Lwww.sybasigns.com.au
C 2001 Syba SignsC 2001 Syba Signs