Notes on Rough Set Approximations and Associated Measures∗
نویسنده
چکیده
We review and compare two definitions of rough set approximations. One is defined by a pair of sets in the universe and the other by a pair of sets in the quotient universe. The latter definition, although less studied, is semantically superior for interpreting rule induction and is closely related to granularity switching in granular computing. Numerical measures about the accuracy and quality of approximations are examined. Several semantics difficulties are commented.
منابع مشابه
Rough ideals based on ideal determined varieties
The paper is devoted to concern a relationship between rough set theory and universal algebra. Notions of lower and upper rough approximations on an algebraic structure induced by an ideal are introduced and some of their properties are studied. Also, notions of rough subalgebras and rough ideals with respect to an ideal of an algebraic structure, which is an extended notion of subalgebras and ...
متن کاملInformation-theoretic measures associated with rough set approximations
Although some information-theoretic measures of uncertainty or granularity have been proposed in rough set theory, these measures are only dependent on the underlying partition and the cardinality of the universe, independent of the lower and upper approximations. It seems somewhat unreasonable since the basic idea of rough set theory aims at describing vague concepts by the lower and upper app...
متن کاملAccurate Topological Measures for Rough Sets
Data granulation is considered a good tool of decision making in various types of real life applications. The basic ideas of data granulation have appeared in many fields, such as interval analysis, quantization, rough set theory, Dempster-Shafer theory of belief functions, divide and conquer, cluster analysis, machine learning, databases, information retrieval, and many others. Some new topolo...
متن کاملRough operations on Boolean algebras
In this paper, we introduce two pairs of rough operations on Boolean algebras. First we define a pair of rough approximations based on a partition of the unity of a Boolean algebra. We then propose a pair of generalized rough approximations on Boolean algebras after defining a basic assignment function between two different Boolean algebras. Finally, some discussions on the relationship between...
متن کاملProbabilistic rough sets: Approximations, decision-makings, and applications
The main objective of this special issue is to present readers with the significantly extended and improved versions of the articles presented at the International Conference on Rough Sets, Fuzzy Sets, and Granular Computing (RSFDGrC’05) held in Regina, Canada in September 2005. In the standard rough set model, the lower and upper approximations are defined based on the two extreme cases (full ...
متن کامل