Research On Method Of Knowledge Acquisition Based On Rough Set Theory

Rough set theory proposed by Poland scholar Z. Pawlak in early 1980's is a powerful tool for data analysis. They have gained increasingly studying in recent years, and have been successfully used in widely fields such as machine learning, decision analysis, process control, knowledge discovery in database, expert system etc. Therefore, studying the method of knowledge acquisition based on rough set theory has important significance.In this thesis, based on rough set theory we make an investigation on the methods of knowledge acquisition in information system. And the main researchful results is as follows,In aspect of decision rules acquisition in information systems, as for consistent decision table, a decision rules mining algorithm based on positive approximation is proposed. The example shows that this algorithm is simple and efficient. These results will be helpful for studying for knowledge discovery based on rough set theory.In aspect of the measure of indiscernibility in imperfect information system, the multivalued information system and the incomplete information system with missing values are unified into a system. As for imperfect information system (include missing data and imprecise data), using the idea...