info.ephyra.questionanalysis.atype.extractor
Class EnglishFeatureExtractor

java.lang.Object
  info.ephyra.questionanalysis.atype.extractor.FeatureExtractor
      info.ephyra.questionanalysis.atype.extractor.EnglishFeatureExtractor

public class EnglishFeatureExtractor
extends FeatureExtractor

Feature extractor for English answer type classification.

See initialize for a description of the input properties required by this class.

See createInstance for a description of the features extracted by this class.

See loadFile for a specification of the input file format.

Version:

2008-02-10

Author:

Justin Betteridge

Field Summary

private static java.lang.String	HOW_MANY_PTRN
private static java.lang.String	HOW_MUCH_OF_PTRN
private static java.lang.String	HOW_MUCH_PTRN
private static java.lang.String	HOW_PTRN
private static org.apache.log4j.Logger	log
private static java.lang.String[]	OF_HEAD_WORDS
private static java.lang.String	REST_PTRN
private static java.lang.String	SPACE_PTRN
private static java.lang.String	WHAT_ANYWHERE_PTRN
private static java.lang.String	WHAT_PTRN
private static java.lang.String	WHEN_PTRN
private static java.lang.String	WHERE_PTRN
private static java.lang.String	WHICH_ANYWHERE_PTRN
private static java.lang.String	WHICH_PTRN
private static java.lang.String	WHO_PTRN
private static java.lang.String	WHOM_PTRN
private static java.lang.String	WHOSE_PTRN
private static java.util.List<java.lang.String>	whPtrns
private static java.lang.String	WHY_PTRN

Fields inherited from class info.ephyra.questionanalysis.atype.extractor.FeatureExtractor

classLevels, datasetExamplePattern, isInitialized, labelPosition, numLoaded, parsePosition, questionPosition, useClassLevels

Constructor Summary

EnglishFeatureExtractor()

Method Summary

private static void	addSemanticFeatures(edu.cmu.minorthird.classify.MutableInstance instance, edu.cmu.lti.javelin.qa.Term focusTerm)
private static void	addSyntacticFeatures(edu.cmu.minorthird.classify.MutableInstance instance, java.util.List<edu.cmu.lti.javelin.qa.Term> terms, java.lang.String parseTree, edu.cmu.lti.javelin.qa.Term focusTerm)
private static void	addWordLevelFeatures(edu.cmu.minorthird.classify.MutableInstance instance, java.util.List<edu.cmu.lti.javelin.qa.Term> terms, edu.cmu.lti.javelin.qa.Term focus)
edu.cmu.minorthird.classify.Instance	createInstance(java.util.List<edu.cmu.lti.javelin.qa.Term> terms, java.lang.String parseTree) Creates and populates an Instance from a QuestionAnalysis object.
edu.cmu.minorthird.classify.Instance	createInstance(java.lang.String question) Creates an Instance for question classification when nothing but the original question is available for feature extraction.
void	initialize() Initializes static resources.

Methods inherited from class info.ephyra.questionanalysis.atype.extractor.FeatureExtractor

createExample, createInstance, getClassLevels, getDatasetExamplePattern, getLabelPosition, getNumLoaded, getParsePosition, getQuestionPosition, isInitialized, isUsingClassLevels, loadFile, printFeatures, printFeaturesFromQuestions, setClassLevels, setDatasetExamplePattern, setInitialized, setLabelPosition, setParsePosition, setQuestionPosition, setUseClassLevels

Methods inherited from class java.lang.Object

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

Field Detail

log

private static final org.apache.log4j.Logger log

HOW_MUCH_PTRN

private static java.lang.String HOW_MUCH_PTRN

HOW_MUCH_OF_PTRN

private static java.lang.String HOW_MUCH_OF_PTRN

HOW_MANY_PTRN

private static java.lang.String HOW_MANY_PTRN

WHOSE_PTRN

private static java.lang.String WHOSE_PTRN

WHO_PTRN

private static java.lang.String WHO_PTRN

WHOM_PTRN

private static java.lang.String WHOM_PTRN

WHAT_PTRN

private static java.lang.String WHAT_PTRN

WHEN_PTRN

private static java.lang.String WHEN_PTRN

WHERE_PTRN

private static java.lang.String WHERE_PTRN

WHY_PTRN

private static java.lang.String WHY_PTRN

HOW_PTRN

private static java.lang.String HOW_PTRN

WHICH_PTRN

private static java.lang.String WHICH_PTRN

WHICH_ANYWHERE_PTRN

private static java.lang.String WHICH_ANYWHERE_PTRN

WHAT_ANYWHERE_PTRN

private static java.lang.String WHAT_ANYWHERE_PTRN

REST_PTRN

private static java.lang.String REST_PTRN

SPACE_PTRN

private static java.lang.String SPACE_PTRN

OF_HEAD_WORDS

private static java.lang.String[] OF_HEAD_WORDS

whPtrns

private static java.util.List<java.lang.String> whPtrns

Constructor Detail

EnglishFeatureExtractor

public EnglishFeatureExtractor()

Method Detail

initialize

public void initialize()
                throws java.lang.Exception

Initializes static resources.

Overrides:

initialize in class FeatureExtractor

Throws:

java.lang.Exception - if one of the required properties is not defined.

addWordLevelFeatures

private static void addWordLevelFeatures(edu.cmu.minorthird.classify.MutableInstance instance,
                                         java.util.List<edu.cmu.lti.javelin.qa.Term> terms,
                                         edu.cmu.lti.javelin.qa.Term focus)

addSyntacticFeatures

private static void addSyntacticFeatures(edu.cmu.minorthird.classify.MutableInstance instance,
                                         java.util.List<edu.cmu.lti.javelin.qa.Term> terms,
                                         java.lang.String parseTree,
                                         edu.cmu.lti.javelin.qa.Term focusTerm)

addSemanticFeatures

private static void addSemanticFeatures(edu.cmu.minorthird.classify.MutableInstance instance,
                                        edu.cmu.lti.javelin.qa.Term focusTerm)

createInstance

public edu.cmu.minorthird.classify.Instance createInstance(java.util.List<edu.cmu.lti.javelin.qa.Term> terms,
                                                           java.lang.String parseTree)

Creates and populates an Instance from a QuestionAnalysis object. All features are binary features of one of the following types:

Word-level features:

• UNIGRAM : individual words in the question
• BIGRAM : pairs of adjacent words in the question
• WH_WORD : the wh-word in the question if one exists

Syntactic features:

• MAIN_VERB: the syntactic head of the sentence, as defined in TreeHelper
• FOCUS_ADJ : the adjective following a wh-word (e.g. 'long' in 'How long is it?')
• WH_DET : whether or not the wh-word is the determiner of a noun phrase, as in 'which printer'

Semantic features:

• FOCUS_TYPE : the semantic type of the focus word,

Specified by:

createInstance in class FeatureExtractor

Parameters:

terms - the Terms of the question

parseTree - the syntactic parse tree of the question

Returns:

an Instance which can be used for question classification

Throws:

java.lang.Exception

createInstance

public edu.cmu.minorthird.classify.Instance createInstance(java.lang.String question)

Description copied from class: FeatureExtractor

Creates an Instance for question classification when nothing but the original question is available for feature extraction. Assumes words in the input question are separated by white-space.

Specified by:

createInstance in class FeatureExtractor

Parameters:

question - the input question

Returns:

the Instance object