| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a retrieval device which is suitable for efficiently narrowing down a document including a designated retrieval character string from a plurality of documents. <P>SOLUTION: In a retrieval device 10 equipped with a storage part 11 which stores a transposition index with appearance positions and appearance frequency as configuring elements about N grams extracted from a plurality of retrieval object document data, an N gram extraction part 13 extracts the N grams from a retrieval character string, and a minimum frequency deriving part 14 derives the N gram having the minimum appearance frequency concerning a plurality of document data among the N grams extracted from the retrieval character string, and a retrieval N gram selection part 15 selects a plurality of retrieval N grams coating the retrieval character string, and including the derived N gram having the minimum appearance frequency from among the N grams extracted from the retrieval character string, and a document specification part 16 specifies document data including the retrieval character string from among the plurality of document data about the plurality of selected retrieval N grams. <P>COPYRIGHT: (C)2012,JPO&INPIT |
