uk.ac.gla.terrier.querying
Class ExplicitQueryExpansion

java.lang.Object
  uk.ac.gla.terrier.querying.QueryExpansion
      uk.ac.gla.terrier.querying.ExplicitQueryExpansion

All Implemented Interfaces:

PostProcess

public class ExplicitQueryExpansion
extends QueryExpansion

Implements automatic query expansion as PostFilter that is applied to the resultset after 1st-time matching using explicit relevance information. Controls

• qemodel : The query expansion model used for Query Expansion. Defaults to Bo1.

Properties

• expansion.terms : The maximum number of most weighted terms in the pseudo relevance set to be added to the original query. The system performs a conservative query expansion if this property is set to 0. A conservation query expansion only reweighs the original query terms without adding new terms to the query.
• expansion.documents : The number of top documents from the 1st pass retrieval to use for QE. The query is expanded from this set of documents, also known as the relevance set.

Version:

$Revision: 1.5 $

Author:

Ben He

Field Summary

Fields inherited from class uk.ac.gla.terrier.querying.QueryExpansion

NAMESPACE_QEMODEL

Constructor Summary

ExplicitQueryExpansion()
The default constructor of QueryExpansion.

Method Summary

void	expandQuery(MatchingQueryTerms query, ResultSet resultSet) This method implements the functionality of expanding a query.

Methods inherited from class uk.ac.gla.terrier.querying.QueryExpansion

getInfo, getQueryExpansionModel, process, setQueryExpansionModel

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ExplicitQueryExpansion

public ExplicitQueryExpansion()

The default constructor of QueryExpansion.

Method Detail

expandQuery

public void expandQuery(MatchingQueryTerms query,
                        ResultSet resultSet)

This method implements the functionality of expanding a query.

Overrides:

expandQuery in class QueryExpansion

Parameters:

query - MatchingQueryTerms the query terms of the original query.

resultSet - CollectionResultSet the set of retrieved documents from the first pass retrieval.