关键词: 粗糙集，完备，约简，条件嫡，不一致决策表

Abstract: Many types of conditional entropy reduction have been proposed and applied in information systems. It is thus important to clarify the relationships among the existing types of conditional entropy reduction. In this paper, the properties of three different conditional entropies were compared and analyzed, then we investigated the relations among three conditional entropy reduction based on different selection strategies,including reduction quality,run time and classification accuracy in cosistent and inconsistent decision table. The experimental result shows that three conditional entropy reducts have different advantages and disadvantages. The above work can give a valuable reference for application.

Key words: Rough set, Complete, Reduction, Conditional entropy, Inconsistent decision table