Abstract: The classical rough set is based on single granulation（equivalence relation）from the perspective of granular computing, It is extended to the multi-granulation rough set based on dominance relation, and the approximate upper and lower are defined. By comparison of the classical rough set, more properties and conclusions based on two-granulation and multi-granulation are got. And the boundary, approximate accuracy, dominance measure, general dominance measure in rough set are studied. Some examples of seismic data are given to illustrate the differences between single-granulation and multi-granulation.

Key words: dominance relation, multi-granulation, rough set, approximate accuracy, dominance measure

摘要： 从粒计算的角度，经典的粗糙集是建立在单一的粒（等价关系）上的，把它推广到建立在优势关系上的多粒度粗糙集，定义了多粒度下的上下近似。通过对经典粗糙集的比较，得到了二粒度和多粒度下粗糙集的一些性质和结论。并在二粒度和多粒度下，对粗糙集里的边界、近似精度、优势度和综合优势度进行了研究。通过地震数据的例子说明了单粒度和多粒度之间的差异。

关键词: 优势关系, 多粒度, 粗糙集, 近似精度, 优势度