Patent Document ID: 20020016787
Application ID: 09892700
Patent Status: 0

Claim One:
1. A similar document retrieving apparatus applicable to a document database D which stores N document data containing a total of M kinds of keywords and is machine processible, for designating a retrieval condition consisting of a document group including at least one document x 1, - - -, x r selected from said document database D and for retrieving documents similar to said document group of said retrieval condition from said document database D, said similar document retrieving apparatus comprising: keyword frequency-of-occurrence calculating means for calculating a keyword frequency-of-occurrence data F which represents a frequency-of-occurrence f dt of each keyword t appearing in each document d stored in said document database D; document length calculating means for calculating a document length data L which represents a length l d of said each document d; keyword weight calculating means for calculating a keyword weight data W which represents a weight w t of each keyword t of said M kinds of keywords appearing in said document database D; document profile vector producing means for producing a M-dimensional document profile vector P d having components respectively representing a relative frequency-of-occurrence p dt of each keyword t in the concerned document d; document principal component analyzing means for performing a principal component analysis on a document profile vector group of a document group in said document database D and for obtaining a predefined (K)-dimensional document feature vector U d corresponding to said document profile vector P d for said each document d; and similar document retrieving means for receiving said retrieval condition consisting of the document group including at least one document x 1, - - -, x r selected from said document database D, calculating a similarity between each document d and said retrieval condition based on a document feature vector of said received document group and the document feature vector of each document d in said document database D, and outputting a designated number of similar documents in order of the calculated similarity.