变精度粗糙集β下近似属性约简

β lower approximation attribute reduction in variable precision rough sets

从属性集角度研究变精度粗糙集模型的属性约简问题,在对象集上定义了一种β下近似二元关系,并利用这种关系建立了属性集及其幂集上的等价关系,由此产生依赖空间。同时利用定义的二元关系和依赖空间给出了变精度粗糙集的β下近似协调集的判定定理,得到一种保持每个决策类的β下近似不变的属性约简方法。最后通过实例验证方法的有效性。

From the view of attribute sets,the attribute reduction in the variable precision rough set model is studied.A new β lower approximation binary relation is defined.Using relations the equivalence relation is constructed on attribute sets and its power sets,and a dependence space is also produced.By applying the binary relation and dependence space,judgement theorems for judging β lower approximation consistent sets are obtained,from which we provide a new attribute reduction algorithm.It can preserve β lower approximation in every decision class.Finally,a practical example illustrates the validity of the method.