Granular Computing in Data Mining

In this study, we are concerned with the role of information granulation in data mining in databases. By their nature, data mining pursuits are very much oriented towards end-users and imply that any results need to be easily interpretable. Granulation of information promotes this interpretability and channels all pursuits of data mining (that are otherwise computationally intensive and thus highly prohibitive) towards more efficient and feasible processing. First, we discuss the essence of information granulation and afterwards elaborate on the main approaches to the design of information granules. We distinguish between user-driven, data-driven and hybrid methods of information granulation. Several main classes of membership functions of information granules-fuzzy sets are investigated and contrasted in terms of some selection criteria such as parametric flexibility and sensitivity of the ensuing information granules. We propose two fundamental concepts in data mining: associations and rules. Associations are direction-free constructs that capture the most essential components of the overall structure in database. The relevance of associations is expressed by the cardinality of the data embraced by the Cartesian products of the information granules contributing to the construction of the associations. The proposed methodology of data mining comprises two phases. First, associations are built and the most essential (relevant) ones are collected in the form of a data mining agenda. Second, some associations can be converted into direction-driven constructs (rules). The idea of consistency of the rules is discussed in detail.