Patent ID: 8886583

Claim:
A recommendation information evaluation apparatus comprising: a processor; a receiving unit that receives a selection of one optional item from a plurality of optional items by a user operation, the plurality of optional items being displayed for the user; a memory that stores a satisfactory feature vector that is a vector of the selected optional item received by the receiving unit and dissatisfactory feature vectors that are vectors of non-selected optional items that were among the plurality of optional items displayed for the user but were not selected; a separation plane generating unit that generates a separation plane for separating in a feature space the satisfactory feature vector of the selected optional item and the dissatisfactory feature vectors of the non-selected optional items, which are stored in the memory, such that the separation plane is a plane that maximizes a distance between the plane and nodes of the satisfactory feature vectors and nodes of the dissatisfactory feature vectors; a user characteristic vector generating unit, implemented by the processor, that generates an orthogonal vector perpendicular to the separation plane, as a user characteristic vector; and an evaluation unit that evaluates an unknown optional item, which is an item that has not been previously displayed to the user for selection, based on the user characteristic vector generated by the user characteristic vector generating unit by calculating an inner product of the user characteristic vector and a characteristic vector of the unknown optional item, wherein the separation plane generating unit calculates the relative position and distance relations in an absolute space between each of a plurality of dissatisfactory feature vectors and a satisfactory feature vector for at least one particular instance of a plurality of optional items being previously displayed for the user, sets all of the dissatisfactory feature vectors to a single origin point in a relative space and sets separate nodes representing the satisfactory feature vectors each a certain position and distance from the origin point in the relative space respectively based on each of the relative positions calculated in the absolute space, and generates the separation plane based on separating the nodes and the origin point in the relative space.