I. INTRODUCTION
Huge amounts of digital data of non-arrangement are
stored by development of information technology over the
internet. This has caused a problem such as a flood of
information. In this surroundings, we wish to acquire only
information needed from huge volumes of information with
speed and elegance. "Information Retrieval Technology" has
therefore focused attention. "Information Retrieval
Technology" is "the technology that search information"
literally. The most conspicuous example is a search engine.
The retrieval method which inputs an optional word and
phrase to a search window becomes popular in everyday life
already