KEYWORD EXTRACTION DEVICE, SIMILAR DOCUMENT RETRIEVAL DEVICE USING THE SAME, KEYWORD EXTRACTION METHOD AND RECORD MEDIUM

摘要

PROBLEM TO BE SOLVED: To highly precisely extract a keyword considering respective documents in a data base from a text given as a keyword extraction object without executing a troublesome processing such as morpheme analysis on the respective documents in the data base. SOLUTION: A word extraction part 12b extracts a word from a keyword extraction object text. Intra-text appearing frequency is obtained at every extracted word and is stored in a word management table 13b. A word retrieval execution part 12c searches the full texts of the respective documents in a document data base storage part 11b at every extracted word. Intra-data base appearing frequency is obtained and is stored in the word management table 13b. A significance calculation part 12d calculates the significance of the respective words based on intra-text appearing frequency and intra-data base appearing frequency, which are stored in the word management table 13b. A keyword deciding part 12e decides a keyword based on the significance of the respective words.