Comparison of Variable Precision Covering Rough Set Models
Keyun Qin · Jisuanji gongcheng · 2008
This paper introduces covering rough sets and Ziarko’s variable precision rough model. Ziarko’s variable precision rough approximation operators are applied to covering approximation space. The concepts of β upper approximation, β lower approximation, β boundary region and β negative region of two kinds of variable precision covering rough set models are given by means of the error parameter β(0≤β0.5). The basic properties of β upper approximation operator and β lower approximation operator in these two models are discussed. The relation of these two kinds of variable precision covering rough set model and the relation of these two models and other rough sets models are investigated.