Meta-information in rough set theory

In original rough set theory, an information system is represented as a single data table describing a set of objects by a set of attributes. In this paper, the information system is generalized by considering a family of subsystems. An information system with more than one subsystem is called a distributed information system. A new concept called meta-information is presented to describe an information system or its subsystems. Algorithms for meta-information integration and derived meta-information generation are proposed. Many existing methods can be reimplemented on the basis of meta-information to avoid the costly work of data integration. Operations on meta-information are very simple and cost-effective. Some applications of meta-information are also discussed.