Information processing using primary and secondary keyword groups

An information processing device, comprising:

• a keyword acquiring unit configured to acquire a plurality of primary keyword and secondary keyword groups, wherein the keyword acquiring unit acquires primary document information including more than one primary keyword, and secondary document information including more than one secondary keyword created by a first user;
• a classifying unit configured to classify each of the plurality of secondary keywords by a plurality of topics based on a topic model, the topics being units for grouping a plurality of keywords having a threshold probability of appearing together in document information;
• an estimating unit configured to estimate whether each primary keyword in the plurality of groups is a related keyword related to any topic having a classified secondary keyword or a mixed keyword unrelated to any of the topics, wherein the estimating unit estimates whether a primary keyword is a related keyword or a mixed keyword on the basis of primary topics having assigned primary keywords and secondary topics having assigned secondary keywords, wherein the estimating unit comprises:
• a topic acquiring unit configured to acquire a primary topic of the primary keyword,
• a match calculating unit configured to calculate the extent of the topic match being the proportion of secondary topics assigned to one or more secondary keywords that are the same as the primary topic,
• a mixed keyword ratio acquiring unit configured to acquire the mixed keyword ratio or the ratio of primary keywords estimated to be mixed keywords among primary keywords included in primary document information from all users, and
• a mixed keyword probability calculating unit configured to calculate the mixed keyword probability of the primary keyword being a mixed keyword on the basis of the extent of the topic match and the mixed keyword ratio;
• and
• an assigning unit configured to assign a primary keyword estimated to be a related keyword to a topic having a classified secondary keyword in the same group, and assign a primary keyword estimated to be a mixed keyword to any of the topics given for classification instead of a dedicated mixed keyword topic such that the primary keyword can later be assigned to a topic if determined to be a related keyword for a different user than the first user.