A View on Rough Set Concept Approximations

نویسندگان

  • Jan G. Bazan
  • Hung Son Nguyen
  • Andrzej Skowron
  • Marcin S. Szczuka
چکیده

The concept of approximation is one of the most fundamental in rough set theory. In this work we examine this basic notion as well as its extensions and modifications. The goal is to construct a parameterized approximation mechanism making it possible to develop multi–stage multi–level concept hierarchies that are capable of maintaining acceptable level of imprecision from input to output.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Rough Set Approximations: a Concept Analysis Point of View

Rough set theory was proposed by Pawlak for analyzing data and reasoning about data. From a concept analysis point of view, we review and reformulate main results of rough set theory in the context of data processing and analysis. This enables us to see clearly the motivations for introducing rough set theory and its basic components and appropriate applications, leading to an appreciation for ...

متن کامل

Some Remarks on the Concept of Approximations from the View of Knowledge Engineering

The concepts of approximations in granular computing (GrC) vs. rough set theory (RS) are examined. Examples are constructed to contrast their differences in the Global GrC Model (2nd GrC Model), which, in pre-GrC term, is called partial coverings. Mathematically speaking, RS-approximations are “sub-base” based, while GrC-approximations are “base” based, where “sub-base” and “base” are two conce...

متن کامل

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 کامل

Rough Set Approximations in Formal Concept Analysis and Knowledge Spaces

This paper proposes a generalized definition of rough set approximations, based on a subsystem of subsets of a universe. The subsystem is not assumed to be closed under set complement, union and intersection. The lower or upper approximation is no longer one set but composed of several sets. As special cases, approximations in formal concept analysis and knowledge spaces are examined. The resul...

متن کامل

Roughness in modules by using the notion of reference points

 module over a ring is a general mathematical concept for many examples of mathematicalobjects that can be added to each other and multiplied by scalar numbers.In this paper, we consider a module over a ring as a universe and by using the notion of reference points, we provide local approximations for  subsets of the universe.

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Fundam. Inform.

دوره 59  شماره 

صفحات  -

تاریخ انتشار 2003