| 摘要 |
The present invention associates user-specific information for specifying a user, who has used a search word, with search time-specific information for specifying a search time at which a search process was executed using the search word; references a search word storage means (12a) for storing the search word; and creates, from search words for which the interval of the search times associated with the same user-specific information are within a prescribed period of time, a search word pair that treats a search word of a previous search time and a search word of a subsequent search time as a pair in accordance with the search time sequence (S4). From among the created search word pairs, the present invention calculates a first number of occurrences of a search word pair (S7); calculates a second number of occurrences of a reverse-sequence search word pair for which the search time sequence was reversed for the search word pair (S8); and, in a case where the magnitude relationship between the first number of occurrences and the second number of occurrences satisfies a prescribed condition, stores the previous search word and the subsequent search word as a thesaurus (S9, S10). |
