10-04-2017, 08:54 PM
[attachment=8481]
BY
Sudheer reddy . B
Agenda
Definition
History
Overview
Performance Measures
What IR Do-How ?
Traditional View of IR
History :
The idea of using computers to search for relevant pieces of information was popularized by the article As We May Think by Vannevar Bush in 1945.
The first automated information retrieval systems were introduced in the 1950s and 1960s.
In 1992, the US Department of Defense along with the NIST cosponsored the Text Retrieval Conference(TREC) program-Web Search Engines.
Overview :
An information retrieval process begins when a user enters a Query into the system.
Process may then be iterated if the user wishes to refine the query.
What IR Systems Try to Do ?
Predict, on the basis of some information about the user, and information about the knowledge resource, what information objects are likely to be the most appropriate for the user to interact with, at any particular time.
How IR Systems Try to Do This
Represent the user s information problem (the query)
Represent (surrogate) and organize (classify) the contents of the knowledge resource
Compare query to surrogates (predict relevance)
Present results to the user for interaction/judgment
Performance measures :
Traditional goal of IR is to retrieve all and only the relevant IOs in response to a query.
All is measured by recall: the proportion of relevant IOs in the collection which are retrieved
Only is measured by precision: the proportion of retrieved IOs which are relevant