9/14/2011

Some of the issues with ir that make a perfect system difficult:

• Representing the document(via bags, inverted index etc) loses some information
• Words may have different meanings in different contexts
• Difficulty in expressing queries that match the documents we really want.

Several techniques can be used to help resolve some of these:

• Relevance feedback
• Correlation-query elaboration via thesaurus etc..
• Principal components analysis

-James Cotter