Global, Local and Mixed Rough Sets Case Base Maintenance Techniques

A major key to success for case-based reasoning systems widely recognized are the definition of suitable case base maintenance policies. The aim of this paper is two fold: (1) to analyse global versus local case base maintenance policies and (2) to develop a unified technique between local and global policies. All the case base maintenance techniques studied in this paper share a common foundation: the Rough Sets theory and its measures of coverage integrated in a Rough Sets competence model. The main purpose of all Rough Sets case base maintenance techniques is to maintain the competence and reduce, as much as possible, its size. Several experiments, using different domains from the UCI and from our repositories, denote that the relation between local and global are quite similar and the unified approach can lead to successful systems in some domains while maintains the competence in other domains.