Information Systems, Rough Set Theory

Rough set(RS) theory was proposed firstly by Z Pawlak who is the scientist in Poland in 1982. After 20 years of researching and developing, it has received achievements in both theories and applications. It does not depend on any previous information except for the data set itself. It also has the strong ability in analyzing and dealing with the information which is imprecise, uncertain and incomplete.In this thesis, we research some problems based on rough set theory in the information system. Our working is shown as follows: 1) propose the algorithm and improved algorithm of minimal reduct. 2) give the minimal cost reduct algorithm. 3) give the reduct algorithm and improved algorithm based on discernibility matrices. 4) give the algorithm of rules. 5) in this thesis, by using RS theory in the synthesis of combinational logic function, we can get minimal expression of logic function; if by using RS theory in the rough control of boiler, we can get rough control rules.