Medical diagnosis: Rough set view

Abstract

This chapter dicusses formalization of medical diagnosis from the viewpoint of rule reasoning based on rough sets. Medical diagnosis consists of the following three procedures. First, screening process selects the diagnostic candidates, where rules from upper approximations are used. Then, from the selected candidates, differential diagnosis is evoked, in which rules from lower approximations are used. Finally, consistency of the diagnosis will be checked with all the inputs: inconsistent symptoms suggest the existence of complications of other diseases. The final process can be viewed as complex relations between rules. The proposed framework successfully formalizes the representation of three types of reasoning styles.