LIS618 lecture 4

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LIS618 lecture 4

• Thomas Krichel
• 2003-02-19

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Structure of talk

• Before online searching
• Introduction to online searching
• Introduction to DIALOG
• Overview
• bluesheets

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before a search I

• what is purpose
• brief overview
• comprehensive search
• What perspective on the topic
• scholarly
• technical
• business
• popular

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before search II

• What type of information
• Fulltext
• Bibliographic
• Directory
• Numeric
• Are there any known sources?
• Authors
• Journals
• Papers
• Conferences

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before search III

• What are the language restrictions?
• What, if any, are the cost restrictions?
• How current need the data to be?
• How much of each record is required?

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DIALOG
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Literature

• http//training.dialog.com/sem_info/courses/pdf_se
  m/dlg1.pdf
• http//training.dialog.com/sem_info/courses/pdf_se
  m/dlg2.pdf
• http//training.dialog.com/sem_info/courses/pdf_se
  m/dlg3.pdf
• http//training.dialog.com/sem_info/courses/pdf_se
  m/dlg4.pdf

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Dialog is a databank

• over 500 databases
• these are also known as files and cover
• references and abstracts for published
  literature,
• business information and financial data
• complete text of articles and news stories
• statistical tables
• Directories
• DIALOG uses the Boolean model

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DIALOG interface

• is still rooted in "traditional" database systems
• dismissed as "dial-a-dog"
• is uses a command-driven interface
• it is very complicated to learn fully
• it is not suitable for the end-user
• it therefore offers a valuable skill to the
  information professional
• it is a challenge for a professor to teach

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Accessing DIALOG

• On the web, go to
• http//www.dialogweb.com/
• Enter username and password, then click on logon
• When it is all done, click logoff in the top menu.

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two steps in DIALOG

• step one select databases (aka files) to look at
  
• step two perform searches on the selected
  databases
• You may wonder why one does not have one single
  step like in a search engine. Discuss.
• today we concentrate on the second step

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working on selected files

• We assume that we have selected database that we
  know and we look at the search interface on the
  selected database.
• The database selection process is a bit more
  complicated, covered next week.
• First, let us login and look at the command
  prompt.
• Then we select the first database (file) with the
  begin command

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The begin command

• As its name suggests, usually the first command.
• begin number, number,
• selects files with numbers number
• Once they are selected they can be searched.
• Now select the ERIC "begin 1"
• "Begin 1" can be abbreviated as "b 1"

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Substeps in the second step

• Identify search terms
• Use Dialog basic commands to conduct a search
• View records online or print the results

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the 's' (select) command

• Once issued the "begin" command to select a
  database, we issue the "s" command on the
  database.
• "s query_terms" where query_terms are the query
  terms
• This will search the index of selected database
  in full-text view for the query issued
• It will not find any of the following "an and by
  for from of the to with". They are stop words.

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connectors

• If you want to use several keywords there are
  three ways
• you can truncate search terms
• you can build an expression by putting several
  keywords together. This is achieved by DIALOG's
  connectors.
• you can combine several expressions with the use
  of Boolean operators
• we will cover this is in turn now

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truncation of terms

• Open Truncation
• "select path?" retrieves all words that begin
  with path paths, pathos, pathway, pathology
• Controlled-Length Truncation
• "select path? ?" retrieves the root and up to
  one additional character paths
• "select path??" retrieves the root and up to two
  additional characters paths, pathos

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truncation of terms II

• Embedded Character truncation can be used for
  variant spellings
• "select organi?ation" -gt organization
  organisation 
• "select fib??board" -gt fiberboard fibreboard 
• This truncation feature is also useful for
  searching for unusual plural forms
• "select wom?n" -gt woman women
• You can also do prefixes by putting the ? in the
  beginning.
• "?mobile" -gt automobile metamobile

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Use of connectors

• Connectors are used to put several words
  together.
• One instance where this is useful is when you
  have words that on their own mean different
  things.
• For example "mate" is a herbal beverage consumed
  in South America. Looking for mate on the
  Internet retrieves a lot of singles' pages.

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terms connected to mate

• What other terms to be used?
• matear (suck mate)
• matero (mate sucker)
• cebar (prepare mate)
• cebador (mate preparer)
• yerba (mate herb)
• bombilla (mate straw)

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connectors I

• '(W)' requires terms to appear one after the
  other next to each other e.g. 'yerba(W)mate?'
  matches "yerba mate".
• '(i W)' where i is an integer, means followed by
  at most i words, e.g. 'ceba?(3W)mate?' matches
  "cebar un maravilloso mate" but not "cebador
  guapo mirando un buen mate"

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connectors II

• '(N)' requires terms to be next to each other
  e.g. 'yerba(N)mate?' matches "yerba mate" or
  "mate yerba".
• '(i N)' where i is an integer, means proximity by
  at most i words, e.g. 'ceba?(3N)mate?' matches
  "cebar mate" or "matear con la cebadora".
• '(S)' searches for the occurrence of connected
  terms in the same paragraph.

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using Boolean operators

• In your query, you can combine several
  expressions with Boolean operators
• Example "?SELECT LIBRARY(W)SCHOOL? AND
  DISTANCE(W)EDUCATION"
• But I usually do not issue such fancy queries.

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executing several searches

• there can be several searches done sequentially,
  and the results sets are saved by the system.
• Each time the system assigns a set number.
• These can be combined in Boolean expressions,
  e.g. 's S1 or S2 and S3'
• Remember that Boolean operations are
  set-theoretic!

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Boolean operators

• when using Booleans, be aware that "and" has
  higher precedence than "or".
• Thus
• a or b and c
• is not the same as
• (a or b) and c
• but it is
• a or (b and c)

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type command

• type set/format/range
• set is a result set
• format is a format
• range can be
• start end
• start is a record number to start
• end is a record number to end
• all

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formats are defined

• 2 -- full record except abstract
• 3 or medium citation
• 5 or long full except full text
• 6 or free title and dialog number
• 8 or short title plus indexing terms
• useful to find other indexing terms
• 9 or full everything
• KWIC or K keywords in context

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http//openlib.org/home/krichel

• Thank you for your attention!