package edu.northwestern.at.utils.corpuslinguistics.postagger.trigramhybrid;
/* Please see the license information at the end of this file. */
import java.util.*;
import edu.northwestern.at.utils.*;
import edu.northwestern.at.utils.corpuslinguistics.adornedword.*;
import edu.northwestern.at.utils.corpuslinguistics.lexicon.*;
import edu.northwestern.at.utils.corpuslinguistics.postagger.*;
import edu.northwestern.at.utils.corpuslinguistics.postagger.hepple.*;
import edu.northwestern.at.utils.corpuslinguistics.postagger.smoothing.contextual.*;
import edu.northwestern.at.utils.corpuslinguistics.postagger.smoothing.lexical.*;
import edu.northwestern.at.utils.corpuslinguistics.postagger.trigram.*;
import edu.northwestern.at.utils.corpuslinguistics.tokenizer.*;
import edu.northwestern.at.utils.math.*;
/** Hybrid Trigram Part of Speech tagger.
*
* <p>
* This trigram part of speech tagger assigns tags to words in a sentence
* assigning the most probable set of tags given the previous tag
* assignments. The Viterbi algorithm is used to reduce the
* amount of computation required to find the optimal tag assignments.
* The Hepple rule-based tagger is used to apply corrections to each
* sentence after the trigram tagger has assigned the initial set of
* tags.
* </p>
*/
public class TrigramHybridTagger
extends TrigramTagger
implements PartOfSpeechTagger
{
/** Create a trigram hybrid tagger.
*/
public TrigramHybridTagger()
{
super();
// Get a lexical smoother.
lexicalSmoother =
new LexicalSmootherFactory().newLexicalSmoother();
lexicalSmoother.setPartOfSpeechTagger( this );
// Get a contextual smoother.
contextualSmoother =
new ContextualSmootherFactory().newContextualSmoother();
contextualSmoother.setPartOfSpeechTagger( this );
// Get a Hepple tagger as the
// fixup tagger.
retagger = new HeppleTagger();
}
/** See if tagger uses contextual rules.
*
* @return True since hybrid tagger uses contextual rules.
*/
public boolean usesContextRules()
{
return true;
}
/** Return tagger description.
*
* @return Tagger description.
*/
public String toString()
{
return "Trigram hybrid tagger";
}
}
/*
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Northwestern University
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