Rough Set Model Based on Characteristic Relations in Incomplete Information System
YANG XiBei1, YANG JingYu1, WU Chen1, 2, YU DongJun1
1.School of Computer Science and Technology, Nanjing University of Science and Technology, Nanjing 210094 2.College of Information Science and Technology, Drexel University, Philadelphia PA 19104, USA
Abstract In this paper, the generalized incomplete information system is taken into consideration, in which unknown values are considered as not only absent but also missing. In this kind of generalized incomplete information system, the characteristic relation is deeply investigated. The classification analysis based on the characteristic relation is discussed due to the two possible unreasonable situations. Therefore, two kinds of new characteristic relations, named as type Ⅰand type Ⅱ, are proposed respectively. Then, characteristic relation of type Ⅲ is constructed by combining the advantages of the previous two new characteristic relations. Finally, an illustrative example is analyzed to indicate the validity of the three new characteristic relations when dealing with the generalized incomplete information systems.
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2007, Vol. 20 
