Abstract: Selection devices, methods and systems for selecting, among a plurality of elements, a nearest neighbor set which is a set of elements each having a relation to a predetermined reference element, a degree of the relation meeting a predetermined condition. A selection device includes: a nearest neighbor set candidate selection unit for selecting, among the plurality of elements, a set of elements determined that the set of elements have stronger relations to the reference element, as each of a plurality of nearest neighbor set candidates, which are a plurality of different candidates for the nearest neighbor set; and a nearest neighbor set selection unit for selecting, as the nearest neighbor set, a set of elements having relations, degrees of which meet the predetermined condition, to the reference element, among a union of the plurality of nearest neighbor set candidates.

Abstract: System for calculating a self-confidence value in selection of a cluster including: evaluation unit selecting a neighbor element set as a target cluster for evaluation, the neighbor element set being a set of a reference number of elements each having a higher correlation with a reference element; a neighbor unit selecting a neighbor element set for each of member elements included in the cluster, the neighbor element set being a set of reference number of elements having a higher correlation with the relevant member element; and a confidence unit which calculating, for a combination of two member elements available from the cluster, the number of elements included both in the neighbor element set for one member element of the combination and in the neighbor element set for the other member element, and outputting an average of ratios calculated for all the combinations of member elements, as the self-confidence value.

Abstract: Provides a computer executable dimension reduction method, a program for causing a computer to execute the dimension reduction method, a dimension reduction device and a retrieval engine using the dimension reduction device. A dimension reduction device for reducing the dimension of a numerical matrix with a computer to provide a dimension reduction matrix and the information comprises a processing part for generating a dimension reduction matrix or the index data for dimension reduction using a random average matrix RAV to store the dimension reduction matrix or the index data. The processing part further comprises a shuffle vector generating part for generating a shuffle vector useful as the shuffle information, and a non-normalized basis vector generating part for generating the non-normalized basis vectors from the numerical elements of the data vector specified by the shuffle vector to store the non-normalized basis vectors.