基于容错粗集的近似信息系统性质讨论

本文将RST从定常信息系统扩展到非定常信息系统,不可分辨关系扩展到不可分辨容错关系.为了探讨近似信息系统的知识表示和知识发现的理论基础,进而对近似信息系统的相似性、容错可定义集和容错粗集等价性、从属空间、相似性矩阵和前象关系矩阵构造方法等代数性质进行了较详细讨论.

基于相似性的近似信息系统概念优化算法

在现实的物理世界中,信息系统允许是不完备的、多值的、近似的、离群的,即非定常的(non-deterministic).本文基于容错粗糙集理论提出非定常信息系统的形式描述,分析了近似信息系统的六种表现,并给出强相似和弱相似的概念.论文在定义了容错粗糙集的相似性测度的基础上,结合FCA理论对不可定义概念进行了扩展,分别对属性不可定义、对象不可定义和上下文不可定义进行了讨论,并给出了相应的近似系统形式概念的最佳逼近算法.实例仿真表明算法具有较好的时间复杂性.

Generalized multi-layered granulations and approximations based on neighborhood systems under incomplete information systems

A generalized multi-layered granulation structure used by neighborhood systems is proposed. With granulated views, the concepts of approximations under incomplete information systems are studied, which are represented by covering of the universe. With respect to different levels of granulations, a pair of lower and upper approximations is defined and an approximation structure is investigated, which lead to a more general approximation structure. The generalized multi-layered granulation structure provides a basis of the proposed framework of granular computing. Using this framework, the interesting and useful results about information granulation and approximation reasoning can be obtained. This paper presents some useful explorations about the incomplete information systems from information views.