Your SlideShare is downloading. ×
Precis
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×

Saving this for later?

Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime - even offline.

Text the download link to your phone

Standard text messaging rates apply

Precis

1,036
views

Published on

Published in: Education, Technology

0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
1,036
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
47
Comments
0
Likes
1
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. PRECIS (PREserved Context Indexing System) Raihanath Dept.of LIS Pondicherry University
  • 2. PRECIS  PREserved Context Indexing System.  Developed by Derek Austin in the early 1970s for subject indexing for the British National Bibliography.  Subsequently developed by him, with the assistance of Mary Dykstra, into an adaptable method of linking both the semantics and syntax of indexing terms.  Goal was to represent meaning without “disturbing the user‟s immediate understanding.”
  • 3. Cont….  It is a development of Chain Indexing.  PRECIS was replaced by COMPASS in 1990.  The British Library compiled an internal thesaurus for PRECIS-indexing of the British National Bibliography from 1950-1987.  The PRECIS thesaurus has, never been available online.
  • 4. Two most important factors worked for the development of PRECIS:  Idea of replacing chain indexing technique of BNB;  The decision of the British Library to generate computer produced BNB with all the indexes in view of launching the UKMARC project
  • 5. Concept of PRECIS  Term: A term is a verbal representation of a concept. It may consist of one or more words.  String: An ordered sequence of component terms, excluding articles connectives, prepositions, etc., proceded by role operators is called a string. The string represents the subject of the document.  Role Operators: The Operators are the code symbols which show the function of the component term and fix its position in the strings. These role operators are meant for the guidance of the indexers only and do not appear in the index entry.
  • 6. Major task involved in indexing according to PRECIS,  Analyzing the document concerned and identifying key     concepts. Organizing the concepts into a subject statement based on the principle of context dependency. Assigning codes which signify the syntactical function of each term. Deciding which terms should be the access points and which terms would be in other positions in the index entries ,and assigning further codes to achieve these results. Adding further prepositions ,auxiliaries or phrases which would result in clarity and expressiveness of the resulting index entries.
  • 7. Primary Operators Enviornment of core concepts 0 Locations Core concepts 1 Key system; Object of transitive action; agent of intransitive action 2 Action; effect of action 3 Performer of transitive action ;intake; factor 4 View point –as-form 5 Selected instance,eg-study region ,sample population 6 Form of document; target user Extra-core concepts
  • 8. Secondary Operators Standard coordinate concept p Part;property Member of quesi-group r Special class of action ‘Bound’coordinate concept q Dependent elements f g Coordinate Concepts Assembly s Role definer t Author-attributed association u Two-way interaction
  • 9. Codes Primary codes 1st concept in coordinate theme 2nd/subsequent concept in theme $z Term codes $x $y Theme interlinks Common concept $a Common noun $c Proper name $d Place name
  • 10. +  In PRECIS entries are generated in a two-line ,three-part format.  The first line, consisting of two lines-the lead and the qualifier. Other line consist of Display.  The lead is the user‟s access point to the index; the qualifier contains the terms that set the lead into its wider context;and the display contains the terms that rely upon the heading for the context.
  • 11. Formats Standard format :  Lead: „Lead‟ position serves as the users‟ approach term, by which a user may search the index.  Qualifier: It represent the term or set of terms which qualifies the lead term to bring it into its proper context.It provides wider context to the lead term.  Display: It is the remaining part of the string which helps to preserve the context. All the terms in the string are prepared using the PRECIS table, are then rotated according to a
  • 12. Cont….. The structure adopted for the process is as follows: Lead Term Qualifier Display The approach term is placed one by one in the lead term section, with the succeeding terms (if any) as qualifier and the preceding terms (if any) in the display section, displaying the context of the terms.
  • 13. Example: Computerization of libraries in India (0) (1) (2) 1. 2. Indian Libraries Computerization INDIA Libraries. Computerization LIBRARIES India Computerization 3.COMPUTERISATION Libraries. India
  • 14. Cont… Predicate Transformation Format The Predicate Transformation Format is used when the teem representing an agent (3) appears as a lead term prefixed by one of the operators 2 or s or t. When such a situation arises, 2 or s or t is shifted to Display position from the Qualifier position. 3. Inverted Format PRECIS makes the use of inverted format when any term is provided the role operators (4), (5) or (6) and these terms appear as Lead terms. When it happens so, the dependant elements are presented in italics (or underlined if handwritten) after a hyphen and the terms in the Qualifier position are printed in Display position. 2.
  • 15. Aspects of PRECIS Indexing:  Context is preserved: The entire indexing     statement appears at each lead term; The permuted entries read naturally, which is achieved by the prescribed order of the role operators; The terms are linked to a machine-held thesaurus (not described in this presentation) thereby providing possible see’s and see also’s ; According to Austin, PRECIS can be adapted to other languages. The indexer determines meaning and codes the roles and lead terms, but the computer takes care of the permutations.
  • 16. Essential Features of PRECIS  The system derives headings that are coextensive with the subject at all access points.  It is not bound to any classification scheme .  The terms are context dependent in nature, which enables the users to identify the entries correctly.  The entries are generated automatically by the computer references between semantically related terms.
  • 17. Cont….  It also provides adequate arrangement of references between semantically related terms.  It is a flexible system, as it is able to incorporate newly emerging terms accordingly.  It has introduced the PRECIS table which puts forth a set pattern for the preparation of entries, thus bringing about consistency in work.
  • 18. Limitation  Indexing with PRECIS requires a good knowledge of grammar;  The bottleneck comes at the first step: articulating the title-like phrase.  It‟s not clear how the terms provided by the indexer are harmonized with the thesaurus to produce “consensual meaning.”
  • 19. Conclusion PRECIS was first adopted by BNB, later on a number of agencies went to accept the system. Among the other national bibliographies that adopted PRECIS are Australia, Malaysia and South Africa. Besides these, a number of libraries in Britain are practicing it. A number of pilot projects are also practicing and for creating indexes to statistical, public and other records.
  • 20. Reference  Chowdhury , G.G(2010).Introduction to Modern Information Retrieval(2nd ed.)New delhi. Facet publication.  Austin, Derek. PRECIS: A Manual of Concept Analysis and Subject Indexing. 2nd ed. London: British Library Bibliographic Services Division, 1984.  http://www.geocities.ws/salman_mlisc/disserta tion/chap5.htm
  • 21. Thank you