Similarity calculation device, similarity calculation system, similarity calculation method, and similarity calculation program

摘要

PROBLEM TO BE SOLVED: To provide a similarity calculation device in which when presenting recommended information, an appropriate similar user can be extracted by reflecting change in taste with time.SOLUTION: A taste information accumulation part 12 stores taste information on a specific user 10 in association with date information at the time of purchasing. A taste information accumulation part 22 stores taste information on each of other users 20a, 20b, 20c, ... in association with date information at the time of purchasing. A similarity calculation part 15 calculates inter-user similarity indicative of a similarity in taste between users on the basis of taste information indicative of a taste of a user and a collection time at which the taste information is collected. A similar user selection part 17 selects a similar user on the basis of the inter-user similarity calculated by the similarity calculation part 15. Since it is determined whether or not another user is appropriate as a similar user on the basis of change in similarity with another user in view of lapse of time, an appropriate similar user can be extracted.