Document retrieval system and question answering system
First Claim
1. A document retrieval system that compares a degree of similarity between a query and a document collection and outputs a retrieved result ranked in order of similarity, comprising:
- an extraction section that extracts a keyword from the query;
a classification section that classifies the keyword extracted by said extraction section into a major type related to a central subject indicated by the query and a minor type related to supplementary information, based on attributes of said keyword; and
a retrieval section that carries out document search processing to obtain the retrieved result ranked in order of similarity based on the classification result of said classification section.
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Abstract
A document retrieval system capable of obtaining information requested by the user with a high degree of accuracy. In this system, the query input section 102 receives query input by the user. The keyword extraction section 104 analyzes the input query and extracts keywords. The keyword type assignment section 106 decides the type of each extracted keyword and assigns a keyword type. The question type decision section 108 decides the question type. The keyword classification section 110 classifies the keywords to which the keyword types are assigned into a major type and minor type with reference to the keyword classification rules stored in the keyword classification rule storage section 112. The document retrieval section 114 searches a document collection stored in the document storage section 116 using the classified keyword groups and obtains the document of the retrieved result.
175 Citations
36 Claims
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1. A document retrieval system that compares a degree of similarity between a query and a document collection and outputs a retrieved result ranked in order of similarity, comprising:
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an extraction section that extracts a keyword from the query;
a classification section that classifies the keyword extracted by said extraction section into a major type related to a central subject indicated by the query and a minor type related to supplementary information, based on attributes of said keyword; and
a retrieval section that carries out document search processing to obtain the retrieved result ranked in order of similarity based on the classification result of said classification section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 34)
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23. A document searching method for comparing the degree of similarity between query and an individual documents in the collection and outputting a retrieved result ranked in order of similarity, comprising:
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an extraction step of extracting keywords from the query;
a classification step of classifying the keywords extracted in said extraction step into a major type related to a central subject indicated by the query and a minor type related to supplementary information based on attributes of said keywords; and
a searching step of carrying out document search processing to obtain retrieved results ranked in order of similarity based on the classification result in said classification step.
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24. A document search program for comparing the degree of similarity between query and an individual documents in the collection and outputting a retrieved result ranked in order of similarity, causing a computer to execute:
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an extraction step of extracting keywords from the query;
a classification step of classifying the keywords extracted in said extraction step into a major type related to a central subject indicated by the query and a minor type related to supplementary information based on attributes of said keywords; and
a searching step of carrying out document search processing to obtain retrieved results ranked in order of similarity based on the classification result in said classification step.
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25. A question answering system comprising:
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a question input section that inputs query;
a question analysis section that analyzes the input query;
a document retrieval section that searches for a document collection based on the analysis result of the query;
an answer generation section that generates an answer to the query based on the document of the retrieved result; and
an answer output section that outputs the answer generated, wherein said question analysis section comprising;
a keyword extraction section that extracts keywords from the input query;
a keyword type assignment section that assigns semantic attributes having hierarchic levels of detailedness to the extracted keywords as the keyword types; and
a question type decision section that decides the type of the query based on the semantic attributes with a level of detailedness assigned to the extracted keywords, said answer generation section comprising;
a semantic attribute assignment section that assigns semantic attributes with a level of detailedness to the keywords in the document of the retrieved result;
an answer candidate selection section that selects answer candidates from expressions of retrieved documents, keywords of which are assigned semantic attributes with a level of detailedness, based on the decision result of said question type decision section and the level of detailedness of said decision result; and
an answer ranking section that ranks the selected answer candidates, and said answer output section outputs the answers based on the ranking result of said answer ranking section. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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35. A question answering method comprising:
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a question input section that inputs query;
a question analysis section that analyzes the input query;
a document retrieval section that searches a document collection based on the analysis result of the query;
an answer generation section that generates answers to the query based on the retrieved documents; and
an answer output section that outputs the generated answers, wherein said question input section comprising a question inputting step of inputting query, said question analysis section comprises a keyword extracting step of extracting keywords from the query input in said question inputting step, said question analysis section comprises a keyword type assigning step of assigning semantic attributes having hierarchic levels of detailedness as keyword types to the keywords extracted in said keyword extracting step, said question analysis section comprises a question type deciding step based on semantic attributes having level of detailedness assigned to the keywords extracted in said keyword extracting step, said document retrieval section comprises a document searching step of searching a document collection based on the query analysis results in said keyword type assigning step and said question type deciding step, said answer generation section comprises a semantic attribute assigning step of assigning semantic attributes with a level of detailedness to keywords in the document of the retrieved result in said document searching step, said answer generation section comprises an answer candidate selecting step of selecting answer candidates from expressions of retrieved documents, keywords of which are assigned semantic attributes with a level of detailedness, in said semantic attribute assigning step based on the decision result in said question type deciding step and the level of detailedness of said decision result, said answer generation section comprises an answer ranking step of ranking the answer candidates selected in said answer candidate selecting step, and said answer output section comprises an answer outputting step of outputting answers based on the ranking result in said answer ranking step.
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36. A question answering program in a question answering system comprising:
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a question input section that inputs query;
a question analysis section that analyzes the input query;
a document retrieval section that searches a document collection based on the analysis result of the query;
an answer generation section that generates answers to the query based on the document of the retrieved result; and
an answer output section that outputs the generated answers, said question answering program causing a computer to execute;
a question inputting step of inputting query;
a keyword extracting step of extracting keywords from the query input in said question inputting step;
a keyword type assigning step of assigning semantic attributes having hierarchic levels of detailedness as keyword types to the keywords extracted in said keyword extracting step;
a question type deciding step of deciding the type of the query based on semantic attributes having a level of detailedness assigned to the keywords extracted in said keyword extracting step;
a document searching step of searching a document collection based on the query analysis results in said keyword type assigning step and said question type deciding step;
a semantic attribute assigning step of assigning semantic attributes with a level of detailedness to keywords in the document of the retrieved result in said document searching step;
an answer candidate selecting step of selecting answer candidates from expressions of retrieved documents, keywords of which are assigned semantic attributes with a level of detailedness, in said semantic attribute assigning step based on the decision result in said question type deciding step and the level of detailedness of said decision result;
an answer ranking step of ranking the answer candidates selected in said answer candidate selecting step; and
an answer outputting step of outputting answers based on the ranking result in said answer ranking step.
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Specification