info.ephyra.questionanalysis
Class PredicateExtractor

java.lang.Object
  info.ephyra.questionanalysis.PredicateExtractor

public class PredicateExtractor
extends java.lang.Object

Extracts predicate-argument structures from a question. At first, the question string is transformed into a statement with a dummy argument, then the predicates are extracted and finally the dummy argument is dropped.

Version:

2007-04-25

Author:

Nico Schlaefer

Field Summary

private static java.lang.String	BE_P Pattern that matches any form of 'to be'.
private static java.lang.String	DATE_TIME_P Pattern for questions seeking a date/time.
private static java.lang.String	DATE_TIME_R Replacement if question is seeking a date/time.
private static java.lang.String	DO_P Pattern that matches any form of 'to do'.
private static java.lang.String	DURATION_R Replacement if question is seeking a location.
private static java.lang.String	HAVE_P Pattern that matches any form of 'to have'.
private static java.lang.String	IGNORE_P Pattern that matches other verb forms which should not be considered as predicates.
private static java.lang.String	INTERROGATIVE_P Pattern that matches any interrogative or 'that'.
private static java.lang.String	LOCATION_P Pattern for questions seeking a location.
private static java.lang.String	LOCATION_R Replacement if question is seeking a location.
private static java.lang.String	MANNER_P Pattern for questions seeking a manner.
private static java.lang.String	MANNER_R Replacement if question is seeking a manner.
private static java.lang.String	PERSON_P Pattern for questions seeking a person.
private static java.lang.String	PERSON_R Replacement if question is seeking a person.
private static java.lang.String	PURPOSE_P Pattern for questions seeking a purpose.
private static java.lang.String	PURPOSE_R Replacement if question is seeking a purpose.
private static java.lang.String	QUANTIFICATION_R Replacement if question is seeking a quantification.
private static java.lang.String	THING_P Pattern for questions seeking a thing.
private static java.lang.String	THING_R Replacement if question is seeking a thing.
private static java.lang.String	UNKNOWN_R Replacement if question is seeking an entity of an unknown type.

Constructor Summary

PredicateExtractor()

Method Summary

private static boolean	containsPredicate(java.lang.String qn) Checks if the question contains a predicate that can be labeled.
static Predicate[]	getPredicates(java.lang.String qn, java.lang.String verbMod, java.lang.String[] ats, Term[] terms) Extracts the predicates from a question string.
private static java.lang.String	handleDateTime(java.lang.String verbMod)
private static java.lang.String	handleIgnore(java.lang.String qn, java.lang.String verbMod, java.lang.String[] tokens, java.lang.String[] pos, java.lang.String[] chunks, int i)
private static java.lang.String	handleLocation(java.lang.String verbMod)
private static java.lang.String	handleManner(java.lang.String qn, java.lang.String verbMod, java.lang.String[] ats, java.lang.String[] tokens, java.lang.String[] pos, java.lang.String[] chunks, int i)
private static java.lang.String	handlePerson(java.lang.String verbMod)
private static java.lang.String	handlePurpose(java.lang.String verbMod)
private static java.lang.String	handleThing(java.lang.String qn, java.lang.String verbMod, java.lang.String[] ats, java.lang.String[] tokens, java.lang.String[] pos, java.lang.String[] chunks, int i)
private static java.lang.String	phraseToRegex(java.lang.String phrase) Transforms a phrase into a regular expression that matches the phrase, allowing differences regarding whitespaces and punctuation and quotation marks.
private static java.lang.String	questionToStatement(java.lang.String qn, java.lang.String verbMod, java.lang.String[] ats) Transforms a question into a statement by replacing phrases with interrogatives.

Methods inherited from class java.lang.Object

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

Field Detail

BE_P

private static final java.lang.String BE_P

Pattern that matches any form of 'to be'.

See Also:

Constant Field Values

DO_P

private static final java.lang.String DO_P

Pattern that matches any form of 'to do'.

See Also:

Constant Field Values

HAVE_P

private static final java.lang.String HAVE_P

Pattern that matches any form of 'to have'.

See Also:

Constant Field Values

IGNORE_P

private static final java.lang.String IGNORE_P

Pattern that matches other verb forms which should not be considered as predicates.

See Also:

Constant Field Values

INTERROGATIVE_P

private static final java.lang.String INTERROGATIVE_P

Pattern that matches any interrogative or 'that'.

See Also:

Constant Field Values

PERSON_P

private static final java.lang.String PERSON_P

Pattern for questions seeking a person.

See Also:

Constant Field Values

THING_P

private static final java.lang.String THING_P

Pattern for questions seeking a thing.

See Also:

Constant Field Values

DATE_TIME_P

private static final java.lang.String DATE_TIME_P

Pattern for questions seeking a date/time.

See Also:

Constant Field Values

LOCATION_P

private static final java.lang.String LOCATION_P

Pattern for questions seeking a location.

See Also:

Constant Field Values

PURPOSE_P

private static final java.lang.String PURPOSE_P

Pattern for questions seeking a purpose.

See Also:

Constant Field Values

MANNER_P

private static final java.lang.String MANNER_P

Pattern for questions seeking a manner.

See Also:

Constant Field Values

PERSON_R

private static final java.lang.String PERSON_R

Replacement if question is seeking a person.

See Also:

Constant Field Values

THING_R

private static final java.lang.String THING_R

Replacement if question is seeking a thing.

See Also:

Constant Field Values

DATE_TIME_R

private static final java.lang.String DATE_TIME_R

Replacement if question is seeking a date/time.

See Also:

Constant Field Values

DURATION_R

private static final java.lang.String DURATION_R

Replacement if question is seeking a location.

See Also:

Constant Field Values

LOCATION_R

private static final java.lang.String LOCATION_R

Replacement if question is seeking a location.

See Also:

Constant Field Values

PURPOSE_R

private static final java.lang.String PURPOSE_R

Replacement if question is seeking a purpose.

See Also:

Constant Field Values

MANNER_R

private static final java.lang.String MANNER_R

Replacement if question is seeking a manner.

See Also:

Constant Field Values

QUANTIFICATION_R

private static final java.lang.String QUANTIFICATION_R

Replacement if question is seeking a quantification.

See Also:

Constant Field Values

UNKNOWN_R

private static final java.lang.String UNKNOWN_R

Replacement if question is seeking an entity of an unknown type.

See Also:

Constant Field Values

Constructor Detail

PredicateExtractor

public PredicateExtractor()

Method Detail

containsPredicate

private static boolean containsPredicate(java.lang.String qn)

Checks if the question contains a predicate that can be labeled.

Parameters:

qn - normalized question string

Returns:

true iff the question contains a predicate

phraseToRegex

private static java.lang.String phraseToRegex(java.lang.String phrase)

Transforms a phrase into a regular expression that matches the phrase, allowing differences regarding whitespaces and punctuation and quotation marks.

Parameters:

phrase - phrase to transform

Returns:

regular expression

handleIgnore

private static java.lang.String handleIgnore(java.lang.String qn,
                                             java.lang.String verbMod,
                                             java.lang.String[] tokens,
                                             java.lang.String[] pos,
                                             java.lang.String[] chunks,
                                             int i)

handlePerson

private static java.lang.String handlePerson(java.lang.String verbMod)

handleThing

private static java.lang.String handleThing(java.lang.String qn,
                                            java.lang.String verbMod,
                                            java.lang.String[] ats,
                                            java.lang.String[] tokens,
                                            java.lang.String[] pos,
                                            java.lang.String[] chunks,
                                            int i)

handleDateTime

private static java.lang.String handleDateTime(java.lang.String verbMod)

handleLocation

private static java.lang.String handleLocation(java.lang.String verbMod)

handlePurpose

private static java.lang.String handlePurpose(java.lang.String verbMod)

handleManner

private static java.lang.String handleManner(java.lang.String qn,
                                             java.lang.String verbMod,
                                             java.lang.String[] ats,
                                             java.lang.String[] tokens,
                                             java.lang.String[] pos,
                                             java.lang.String[] chunks,
                                             int i)

questionToStatement

private static java.lang.String questionToStatement(java.lang.String qn,
                                                    java.lang.String verbMod,
                                                    java.lang.String[] ats)

Transforms a question into a statement by replacing phrases with interrogatives.

Parameters:

qn - normalized question string

verbMod - question string with modified verbs

ats - expected answer types

Returns:

statement

getPredicates

public static Predicate[] getPredicates(java.lang.String qn,
                                        java.lang.String verbMod,
                                        java.lang.String[] ats,
                                        Term[] terms)

Extracts the predicates from a question string.

Parameters:

qn - normalized question string

verbMod - question string with modified verbs

ats - expected answer types

terms - question terms

Returns:

predicate-argument structures