منابع مشابه
Fuzzy rough approximations for set-valued data
Rough set theory is one of important tools of soft computing, and rough approximations are the essential elements in rough set models. However, the existing fuzzy rough set model for set-valued data, which is directly constructed based on a kind of similarity relation, fail to explicitly define fuzzy rough approximations. To solve this issue, in this paper, we propose two types of fuzzy rough a...
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Multisets alias bags are similar to fuzzy sets but essentially different in basic concepts and operations. We overview multisets together with basics of fuzzy sets in order to observe differences between the two. We then introduce fuzzy multisets and the combination of the both concepts. There is another concept of real-valued multisets as a generalization of multisets. Rough approximations of ...
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It is estimated that every 20 months or so the amount of information in the world doubles. In the same way, tools that mine knowledge from data must develop to combat this growth. Such techniques must be able to extract useful, meaningful patterns efficiently in the presence of large amounts of noisy, redundant and sometimes misleading information. To be able to achieve this, data mining is oft...
متن کاملFuzzy Similarity Relation as a Basis for Rough Approximations
The indiscernibility relation originally used for the de nition of the rough set concept is extended to a similarity relation subject to a minimal set of conditions. It is shown that in order to meet these conditions, the similarity relation needs only to be re exive. The lower and upper approximations are de ned according to a new more general de nition using the similarity relation. Compariso...
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Rough set theory, introduced by Pawlak [10], is a mathematical formalism dealing with uncertainty and to some extent overlapping fuzzy set theory introduced by Zadeh [12]. In fuzzy set theory vagueness is expressed by a membership function. The rough set theory approach is based on indiscernibility relations and approximations. A major advantage of rough set theory is that it needs no prelimina...
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ژورنال
عنوان ژورنال: International Journal of Approximate Reasoning
سال: 2008
ISSN: 0888-613X
DOI: 10.1016/j.ijar.2007.03.016