优势关系下属性值粗化细化时近似集分析

基于优势关系粗糙集模型反映属性间的偏好情况，实际上多数数据库中的数据是动态变化的。如何利用已有的信息更新近似集对于提高知识发现效率有重要意义。提出不完备信息系统在优势关系下属性值粗化细化的定义，讨论优势关系下不完备信息系统中属性值粗化细化时近似集的变化情况，对比分析优势关系下属性值粗化细化前后的粗糙近似精度和粗糙近似质量。通过实例分析验证了该方法的有效性。

Analysis of Approximations Under Dominance Relation During Attribute Values Coarsening and Refining

In the dominance-based rough sets approach, attributes values in information systems have preference relation. Many data sources have dynamic characteristics. How to update approximations based on the original approximations information is an important problem since it may improve the efficiency of knowledge discovery. This paper provides the definitions of attribute values coarsening and refining based on the dominance relation in incomplete information systems, focuses on discussing and analyzing the change of upper and lower approximations, rough approximation accuracy and the quality of rough approximations in incomplete information systems based on the dominance relation while attribute values are coarsened or refined respectively. An example is used to illustrate the validity of the method.