Patent ID: 6321189
Filing Date: 2001-11-20
Classification: G06F,Y10S

Abstract:
A cross-lingual retrieval system comprising:pair data storing means for storing a plurality of pair data each having a first language sentence and a second language sentence having the same meaning;query receiving means for receiving a query written in the first language;first retrieving means for retrieving first language sentences similar to the query from among a set of the first language sentences stored in the pair data storing means; andsecond retrieving means for retrieving second language sentences similar to second language sentences paired with the respective first language sentences retrieved by the first retrieving means from among a set of the second language sentences stored in the pair data storing means;wherein the second retrieving means determines and extracts important words from each of second language sentences having the same meaning and paired with the respective first language sentences retrieved by the first retrieving means, provides a degree of importance to each of the important words and retrieves similar second language sentences using the important words and their degree of importance, wherein, for the set A of the second language sentences stored in the pair data storing means, a set B of the second language sentences having the same meaning and paired with the respective first language sentences retrieved by the first retrieving means and a set C of all words appearing in the set B, a first value that is the number of sentences included in the set B, a second value that is the number of sentences in the set B for each important word candidate containing the important word candidate, supposing that all the words in the set C are the important word candidates, and a third value that is the number of sentences in the set A for each important word candidate containing the important word candidate are computed, and the degree of importance of each important word candidate is obtained using the first, second and third values as variables to determine the important word from among the important word candidates based on the degree of importance; andretrieving means takes one of the following values as the degree of importance of each important word candidate:extended mutual information=log.sub.2 {(M.beta.)/(.alpha..gamma.)};extended t-score=M{(M.beta.-.alpha..gamma.)/(.alpha..gamma.)}; andextended Dice-coefficient=2.beta./(.alpha.+.gamma.),wherein the number of sentences included in the set A is referred to as M, the first value is referred to as .alpha., the second value for each important word candidate is referred to as .beta. and the third value for each important word candidate is referred to as .gamma..