Non-factoid question-answering system and method
First Claim
1. A non-factoid question-answering system connected to a document storage for storing a plurality of computer-readable documents, the system comprising:
- a processor configured to;
receive a non-factoid question as an input;
responsive to the question, retrieve answer candidates to the question from said document storage;
create question and answer candidates comprising combinations of said question and each of the answer candidates;
for each question and answer candidate, generate a set of prescribed features comprising;
calculating a first set of features obtained from respective morpheme information and syntactic information;
in the answer of the question and answer candidate, selecting a causal relation expression based on a matching relationship; and
calculating a second set of features obtained from said selected causal relation expression based on a polarity of the selected causal relation expression, wherein said set of prescribed features includes said first set of features and said second set of features;
for the set of prescribed features and the question and the answer candidate used as a base for generating the set of features, calculate a score representing a degree of plausibility of the answer candidate as a correct answer to the question;
output an answer candidate having the highest score as an answer to the question;
specify, in each of said answer candidates, an expression serving as a clue for specifying a casual relation expression;
specify a causal relation expression consisting of a cause part and a result part of causal relation connected by a specified clue expression, in each of said answer candidates;
determine whether a combination of a noun and a polarity of a predicate on which the noun depends, included in the result part of said specified causal relation expression, matches a combination of a noun and a polarity of a predicate on which the noun depends, included in the question;
determine a relevance of the specified causal relation expression in each of said answer candidates based on word matching and dependency tree matching between each of said answer candidates and said question, andoutput, as features of said second feature set, information representing a result of the determination.
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Abstract
A question-answering system capable of appropriately answering a non-factoid question. The question-answering system responsive to a question, for taking out answer candidates from an object document storage unit; extracting plausible ones from the answer candidates; recognizing causal relation expression included in extracted answer candidates; determining whether or not a recognized causal relation is relevant as an answer; generating a feature vector related to a combination of the question and the searched answer candidate; and for calculating, when a feature vector is given, a score indicating a degree of how correct an answer candidate is as an answer to the question, for the question and the answer candidate as a source of the feature vector, and for outputting, as the answer to the question, an answer candidate having the highest score.
8 Citations
5 Claims
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1. A non-factoid question-answering system connected to a document storage for storing a plurality of computer-readable documents, the system comprising:
a processor configured to; receive a non-factoid question as an input; responsive to the question, retrieve answer candidates to the question from said document storage; create question and answer candidates comprising combinations of said question and each of the answer candidates; for each question and answer candidate, generate a set of prescribed features comprising; calculating a first set of features obtained from respective morpheme information and syntactic information; in the answer of the question and answer candidate, selecting a causal relation expression based on a matching relationship; and calculating a second set of features obtained from said selected causal relation expression based on a polarity of the selected causal relation expression, wherein said set of prescribed features includes said first set of features and said second set of features; for the set of prescribed features and the question and the answer candidate used as a base for generating the set of features, calculate a score representing a degree of plausibility of the answer candidate as a correct answer to the question; output an answer candidate having the highest score as an answer to the question; specify, in each of said answer candidates, an expression serving as a clue for specifying a casual relation expression; specify a causal relation expression consisting of a cause part and a result part of causal relation connected by a specified clue expression, in each of said answer candidates; determine whether a combination of a noun and a polarity of a predicate on which the noun depends, included in the result part of said specified causal relation expression, matches a combination of a noun and a polarity of a predicate on which the noun depends, included in the question; determine a relevance of the specified causal relation expression in each of said answer candidates based on word matching and dependency tree matching between each of said answer candidates and said question, and output, as features of said second feature set, information representing a result of the determination. - View Dependent Claims (2, 3, 4)
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5. A non-factoid question-answering method performed by a processor and executed by using document storage for storing a plurality of computer-readable documents, the method comprising:
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receive a non-factoid question as an input responsive to the question, retrieve using the processor answer candidates to the question from said document storage; using the processor, create question and answer candidates comprising combinations of said question and each of the answer candidates; for each question and answer candidate, generate using the processor a set of prescribed features comprising; calculating a first set of features obtained from respective morpheme information and syntactic information; in the answer of the question and answer candidate, selecting a causal relation expression based on a matching relationship; and calculating a second set of features obtained from said selected causal relation expression based on a polarity of the selected causal relation expression, wherein said set of prescribed features includes said first set of features and said second set of features; for the set of prescribed features and the question and the answer candidate used as a base for generating the set of features, calculate a score representing a degree of plausibility of the answer candidate as a correct answer to the question; output an answer candidate having the highest score as an answer to the question; specify, in each of said answer candidates, an expression serving as a clue for specifying a causal relation expression; specify a causal relation expression consisting of a cause part and a result part of causal relation connected by a specified clue expression, in each of said answer candidates; determine whether a combination of a noun and a polarity of a predicate, on which the noun depends, included in the result part of said specified causal relation expression, matches a combination of a noun and a polarity of a predicate on which the noun depends, included in the question; determine a relevance of the specified causal relation expression in each of said answer candidates based on word matching and dependency tree matching between each of said answer candidates and said question, and output, as features of said second feature set, information representing a result of the determination.
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Specification