Upper Approximation Reduction Based on Intuitionistic Fuzzy $\mathcal{T}$ Equivalence Information Systems

Author(s):  
Weihua Xu ◽  
Yufeng Liu ◽  
Wenxin Sun
2013 ◽  
Vol 5 (4) ◽  
pp. 445-458 ◽  
Author(s):  
B. Davvaz ◽  
M. Jafarzadeh

2012 ◽  
Vol 548 ◽  
pp. 735-739
Author(s):  
Hong Mei Nie ◽  
Jia Qing Zhou

Rough set theory has been proposed by Pawlak as a useful tool for dealing with the vagueness and granularity in information systems. Classical rough set theory is based on equivalence relation. The covering rough sets are an improvement of Pawlak rough set to deal with complex practical problems which the latter one can not handle. This paper studies covering-based generalized rough sets. In this setting, we investigate common properties of classical lower and upper approximation operations hold for the covering-based lower and upper approximation operations and relationships among some type of covering rough sets.


Author(s):  
ZHIMING ZHANG ◽  
JINGFENG TIAN

Intuitionistic fuzzy (IF) rough sets are the generalization of traditional rough sets obtained by combining the IF set theory and the rough set theory. The existing research on IF rough sets mainly concentrates on the establishment of lower and upper approximation operators using constructive and axiomatic approaches. Less effort has been put on the attribute reduction of databases based on IF rough sets. This paper systematically studies attribute reduction based on IF rough sets. Firstly, attribute reduction with traditional rough sets and some concepts of IF rough sets are reviewed. Then, we introduce some concepts and theorems of attribute reduction with IF rough sets, and completely investigate the structure of attribute reduction. Employing the discernibility matrix approach, an algorithm to find all attribute reductions is also presented. Finally, an example is proposed to illustrate our idea and method. Altogether, these findings lay a solid theoretical foundation for attribute reduction based on IF rough sets.


2011 ◽  
Vol 204-210 ◽  
pp. 1781-1784
Author(s):  
Bin Chen

Rough sets, a tool for data mining, deal with the vagueness and granularity in information systems. This paper studies covering-based rough sets from the topological view. We explore the relationship between the relative closure and the second type of covering upper approximation. The major contributions of this paper are that we use the definition of the relative closure and the relative interior to discuss the conditions under which the relative operators satisfy certain classical properties. The theorems we get generalize some of the results in Zhu’s paper.


2013 ◽  
Vol 12 (13) ◽  
pp. 2505-2511 ◽  
Author(s):  
Beiling Ma ◽  
Chunqiao Tan ◽  
Zhong-Zhong Jiang ◽  
Hepu Deng

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