Invalidity Patent Search System of NTT DATA

Abstract

In this paper, we give an overview of our invalidity patent search system for NTCIR-4 PATENT. The system is based on the document retrieval technique and the new methods that are suitable for the invalidity search; the query term extraction based on characteristics of invention, the retrieval model using components of invention, the ranking using the term weighting based on category information, and so on. This paper describes these methods, and evaluates the search results given by our methods.