Structural decomposition of technological domain using patent co-classification and classification hierarchy

Abstract

This paper proposes a new method for decomposing a technological domain (TD). Specifically, the method identifies sub-TDs at the different levels of technological hierarchy within the TD based on the characteristics of patent co-classification and classification hierarchy. We defined the smallest class, named Minimum Overlapped Class (MOC), constructed by overlaps of sub-group IPC(s) and sub-class UPC(s), and sub-TD is basically identified as a set of the MOCs. In order to cluster the MOCs, technological distances among MOCs are calculated based on patent co-classification and hierarchical structure of patent classification systems. Technologically similar MOCs are grouped by using a hierarchical clustering and the identified clusters at the different level of hierarchy show the hierarchical structure of a TD. Detailed technological content for each sub-TD is represented by extracting representative keywords through a text-mining technique. The method is empirically tested by the solar photovoltaic technology and the results show that the identified sub-TDs are reasonably acceptable by qualitative analysis.