info.ephyra.answerselection.filters
Class PredicateExtractionFilter

java.lang.Object
  info.ephyra.answerselection.filters.Filter
      info.ephyra.answerselection.filters.PredicateExtractionFilter

public class PredicateExtractionFilter
extends Filter

Extracts predicates which are similiar to those in the question from documents.

This class extends the class Filter.

Version:

2007-07-17

Author:

Nico Schlaefer

Field Summary

private static int	MAX_SENT_LENGTH_CHARS Maximum length of a sentence in characters to be considered for predicate extraction.
private static int	MAX_SENT_LENGTH_TOKENS Maximum length of a sentence in tokens to be considered for predicate extraction.
private static int	MAX_SENTENCES Maximum number of sentences that are annotated with predicate-argument structures.

Constructor Summary

PredicateExtractionFilter()

Method Summary

Result[]	apply(Result[] results) Extracts relevant predicates from documents.
private boolean	checkSentence(Result sentence) Decides if predicates should be extracted from this sentence.
private java.util.Map<java.lang.String,java.lang.String[]>	extractNes(java.lang.String sentence, java.lang.String[] answerTypes) Extracts NEs of the expected answer types from a sentence.
private java.util.Hashtable<java.lang.String[],java.lang.Double>	getAllVerbForms(Predicate[] ps) Gets all forms of the verbs and expansions of predicates with missing arguments.

Methods inherited from class info.ephyra.answerselection.filters.Filter

apply

Methods inherited from class java.lang.Object

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

Field Detail

MAX_SENTENCES

private static final int MAX_SENTENCES

Maximum number of sentences that are annotated with predicate-argument structures.

See Also:

Constant Field Values

MAX_SENT_LENGTH_CHARS

private static final int MAX_SENT_LENGTH_CHARS

Maximum length of a sentence in characters to be considered for predicate extraction.

See Also:

Constant Field Values

MAX_SENT_LENGTH_TOKENS

private static final int MAX_SENT_LENGTH_TOKENS

Maximum length of a sentence in tokens to be considered for predicate extraction.

See Also:

Constant Field Values

Constructor Detail

PredicateExtractionFilter

public PredicateExtractionFilter()

Method Detail

extractNes

private java.util.Map<java.lang.String,java.lang.String[]> extractNes(java.lang.String sentence,
                                                                      java.lang.String[] answerTypes)

Extracts NEs of the expected answer types from a sentence.

Parameters:

sentence - the sentence

answerTypes - the expected answer types

Returns:

NEs and their types

getAllVerbForms

private java.util.Hashtable<java.lang.String[],java.lang.Double> getAllVerbForms(Predicate[] ps)

Gets all forms of the verbs and expansions of predicates with missing arguments. The verb forms are associated with their weights.

Parameters:

ps - predicates

Returns:

verb forms and their weights

checkSentence

private boolean checkSentence(Result sentence)

Decides if predicates should be extracted from this sentence. If the sentence passes the tests, NEs of the expected answer types and terms are extracted and added to the result.

Parameters:

sentence - sentence-level result

Returns:

true iff the sentence is relevant

apply

public Result[] apply(Result[] results)

Extracts relevant predicates from documents.

Overrides:

apply in class Filter

Parameters:

results - array of Result objects containing documents

Returns:

array of Result objects containing predicates