Information retrieval system, an information retrieval method, a program for executing information retrieval, and a storage medium wherein a program for executing information retrieval is stored

An information retrieval method for retrieving documents added to a database with respect to time, said documents being converted into document-attribute matrix and stored within said information retrieval system, and said document-attribute matrix being constituted by document-attribute submatrices added in order with respect to time, said information retrieval system comprising the steps of:

• generating and storing a predetermined type matrix from said document-attribute matrix,
• generating said document-attribute submatrix from documents being added to said database during a specific time period,
• updating said predetermined type matrix using knowledge with respect to said document-attribute submatrix and for executing the singular value decomposition on updated said predetermined type matrix to execute dimension reduction of all document-attribute matrices stored within said database, and
• retrieving information with respect to a user input query using said dimension reduced document-attribute matrix.

A program for retrieving documents, said documents being converted into document-attribute matrix and stored within said information retrieval system, and said document-attribute matrix being constituted by document-attribute submatrices added in order with respect to time, said program making a computer execute the steps of:

• generating and storing a predetermined type matrix from said document-attribute matrix,
• generating said document-attribute submatrix from documents being added to said database during a specific time period,
• updating said predetermined type matrix using knowledge with respect to said document-attribute submatrix and for executing the singular value decomposition on updated said predetermined type matrix to execute dimension reduction of all document-attribute matrices stored within said database, and
• retrieving information with respect to a user input query using said dimension reduced document-attribute matrix.

A storage medium readable by a computer wherein a program for making a computer execute an information retrieval method to retrieve documents, said documents being converted into document-attribute matrix and stored within said information retrieval system, and said document-attribute matrix being constituted by document-attribute submatrices added in order with respect to time, said program making a computer execute said information retrieval method comprising the steps of:

• generating and storing a predetermined type matrix from said document-attribute matrix,
• generating said document-attribute submatrix from documents being added to said database during a specific time period,
• updating said predetermined type matrix using knowledge with respect to said document-attribute submatrix and for executing the singular value decomposition on updated said predetermined type matrix to execute dimension reduction of all document-attribute matrices stored within said database, and
• retrieving information with respect to a user input query using said dimension reduced document-attribute matrix.