Patent ID: 7024400

Claim:
A method of setting up a DLSI space-based classifier to be stored in a computer storage device for document classification using a computer, and using said classifier by said computer to classify a document according to a plurality of clusters within a database, comprising the steps of: preprocessing documents using said computer to distinguish terms of a word and a noun phrase from stop words; constructing system terms by setting up a term list as well as global weights using said computer; normalizing document vectors of collected documents, as well as centroid vectors of each cluster using said computer; constructing a differential term by intra-document matrix D I m×n I using said computer, such that each column in said matrix is a differential intra-document vector; decomposing the differential term by intra-document matrix D I , by an SVD algorithm using said computer, into D I =U I S I V I T (S I =diag(δ I,1 ,δ I,2 , . . . )), followed by a composition of D I,k I =U k I S k I V k I T giving an approximate D I in terms of an appropriate k I ; setting up a likelihood function of intra-differential document vector using said computer; constructing a term by extra-document matrix D E m×n E using said computer, such that each column of said extra-document matrix is an extra-differential document vector; decomposing D E , by exploiting the SVD algorithm using said computer, into D E =U E S E V E T (S E =diag(δ E,1 ,δ E,2 , . . . )), then with a proper k E , defining D E,k E =U k E S k E V k E T to approximate D E ; setting up a likelihood function of extra-differential document vector using said computer; setting up a posteriori function using said computer; and said computer using said DLSI space-based classifier, as set up in the foregoing steps, to classify the document as belonging to one of the plurality of clusters within the database.