Patent ID: 7308138

Claim:
A method for segmenting a given input document, comprising: detecting terms that occur in said input document; segmenting said input document into document segments, each segment being an appropriately sized chunk; generating document segment vectors with, as their elements, values related to frequencies of said terms occurring in said document segments; calculating eigenvalues and eigenvectors of a square sum matrix of said document segment vectors; selecting basis vectors defining a subspace from said eigenvectors; calculating projection vectors with, as their elements, values corresponding to projection values of the each document segment vector onto said basis vectors; using the projection vectors, calculating a topic continuity of the document segments; and determining segmentation points of said document based on the calculated topic continuity of said document segments; wherein when said input document, in which K terms occur, is divided into N document segments, said square sum matrix, denoted as A ab , is calculated by a following equation: A ab = ∑ n = 1 N ⁢ ⁢ s n ⁢ ⁢ a ⁢ s n ⁢ ⁢ b where s na and s nb represent values corresponding to the occurrence frequencies of the a-th and b-th terms, respectively, in the n-th document segment, and the n-th document segment vector s n (n=1, . . . , N) is represented by (s n1 , s n2 , . . . , s nk ) T .