A Rough Set Approach to Incomplete Data

摘要

This paper presents main directions of research on a rough set approach to incomplete data. First, three different types of lower and upper approximations, based on the characteristic relation, are defined. Then an idea of the probabilistic approximation, an extension of lower and upper approximations, is presented. Local probabilistic approximations are also discussed. Finally, some special topics such as consistency of incomplete data and a problem of increasing data set incompleteness to improve rule set quality, in terms of an error rate, are discussed.