earticle

영어

To investigate the association of data with other data in reality, the research begins with data sets which are divided into different partitions. Because each partition consists of granules and owns a level, all the partitions constitute a granulation set whose elements are the granules. As a hierarchy system, the granulation set together with the inclusion relation gives rise to a structure called a granulation tree. The research on the data association establishes a method to describe the associations of the data in a granulation tree with the data in another granulation tree. The method involves a necessary and sufficient condition used to check the data associations. Because the necessary and sufficient condition is bound up with the upper approximation, the study also develops a way of investigation into rough sets. As an example, a practical problem is modeled by granulation trees, and the associations of the data in a granulation tree with the data in another granulation tree can be examined by use of the necessary and sufficient condition. Meanwhile, because the study is closely linked to granules and alterations of granularity, the process can be viewed as an approach to research on granular computing