To decide a category belonging to a document in the range suitable to each category and then to decide a proper category by deriving a threshold belonging to the category and judging whether the document that is newly inputted belongs to the category based on the derived threshold.
A category decision part 212 refers to the average vector of each category that is held at an average vector holding part 208, the threshold of each category that is held at a threshold holding part 210, and the document vector which is held at a desired document vector holding part 211 respectively. Then, the category that includes the desired document vector within the threshold is decided as the category of a desired document, and this decided category is held at a sort result holding part 213. Thus, it's possible to properly sort the categories which are designated by a training document by setting the threshold in every category to designate a category range even if the distribution range of the training document vector differs in every category.
ITO SHIRO
UEDA TAKANARI
IKEDA YUJI
