共查询到17条相似文献,搜索用时 76 毫秒
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本文研究了模糊粗糙集中属性约简问题.利用模糊粗糙集和多粒度粗糙集各自优点的结合,提出了两类多粒度模糊粗糙集模型,使得两类粗糙集中的上下近似算子关于负算子对偶.同时研究了多粒度模糊粗糙集的性质及与单粒度模糊粗糙集的关系.并通过构造区分函数的方法提出了一类多粒度模糊粗糙集模型的近似约简方法.最后用一个实例核对了该类多粒度模糊粗糙决策系统近似约简方法的有效性. 相似文献
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回顾了由二元关系产生的粗糙近似空间及其导出的各种粗糙近似算子的构造性定义,介绍了经典和模糊环境下各种信任结构及其导出的信任函数与似然函数的概念,给出了粗糙集理论中近似空间及其导出的下近似算子与上近似算子和证据理论中的信任结构及其导出信任函数与似然函数之间的相互关系及其应用背景。 相似文献
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基于包含度的模糊随机粗糙集模型 总被引:1,自引:0,他引:1
针对随机性与模糊性同时存在的情形,提出了建立在模糊随机近似空间上的基于包含度的模糊随机粗糙集模型.首先给出了模糊随机近似空间的概念,然后利用包含度提出了模糊随机近似空间上的一种基于模糊随机集的粗糙近似算子.最后讨论了这种近似算子的一些性质. 相似文献
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基于覆盖的模糊粗糙集模型 总被引:16,自引:1,他引:15
讨论基于覆盖理论的模糊粗糙集模型。给出了模糊集的粗糙上、下近似算子,讨论了算子的基本性质,证明了覆盖粗糙集模型下所有模糊集的下近似构成一个模糊拓扑,并得到了覆盖模糊粗糙集模型的公理化描述。 相似文献
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首先在一般区间值模糊关系上定义了两个论域上的一类广义区间值模糊粗糙集.借助区间值模糊集的截集给出区间值模糊粗糙上、下近似算子的一般表示.讨论了各种特殊的区间值模糊关系与区间值模糊近似算子性质之间的等价刻画.最后利用公理化方法刻画区间值模糊粗糙集.描述区间值模糊上、下近似算子的公理集保证了生成相同近似算子的区间值模糊关系的存在性. 相似文献
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This paper is devoted to the discussion of homomorphic properties of fuzzy rough groups.The fuzzy approximation space was generated by fuzzy normal subgroups and the fuzzy rough approximation operators were discussed in the frame of fuzzy rough set model.The basic properties of fuzzy rough approximation operators were obtained. 相似文献
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On characterization of generalized interval-valued fuzzy rough sets on two universes of discourse 总被引:2,自引:0,他引:2
This paper proposes a general study of (I,T)-interval-valued fuzzy rough sets on two universes of discourse integrating the rough set theory with the interval-valued fuzzy set theory by constructive and axiomatic approaches. Some primary properties of interval-valued fuzzy logical operators and the construction approaches of interval-valued fuzzy T-similarity relations are first introduced. Determined by an interval-valued fuzzy triangular norm and an interval-valued fuzzy implicator, a pair of lower and upper generalized interval-valued fuzzy rough approximation operators with respect to an arbitrary interval-valued fuzzy relation on two universes of discourse is then defined. Properties of I-lower and T-upper interval-valued fuzzy rough approximation operators are examined based on the properties of interval-valued fuzzy logical operators discussed above. Connections between interval-valued fuzzy relations and interval-valued fuzzy rough approximation operators are also established. Finally, an operator-oriented characterization of interval-valued fuzzy rough sets is proposed, that is, interval-valued fuzzy rough approximation operators are characterized by axioms. Different axiom sets of I-lower and T-upper interval-valued fuzzy set-theoretic operators guarantee the existence of different types of interval-valued fuzzy relations which produce the same operators. 相似文献
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利用k阶二元关系定义直觉模糊粗糙集,讨论了分别为串行、自反、对称、传递关系时所对应的上、下近似算子的性质。在有限论域U中,研究了任一自反二元关系所诱导的直觉模糊拓扑空间中直觉模糊闭包、内部算子与相对应的上、下近似算子的关系。 相似文献
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In the present paper, we mainly discuss the (??,?)-generalized fuzzy rough sets introduced by B.Q. Hu and Z.H. Huang with both constructive approach and axiomatic approach considered. In the former, we started from the investigation of the properties of the ??-upper and ?-lower approximation operators generated by binary fuzzy relations. In the latter, by defining a pair of fuzzy set-theoretic operators, we show (??,?)-fuzzy rough approximation operators can be characterized by different sets of axioms. 相似文献
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The combination of the rough set theory, vague set theory and fuzzy set theory is a novel research direction in dealing with incomplete and imprecise information. This paper mainly concerns the problem of how to construct rough approximations of a vague set in fuzzy approximation space. Firstly, the β-operator and its complement operator are introduced, and some new properties are examined. Secondly, the approximation operators are constructed based on β-(complement) operator. Meantime, λ-lower (upper) approximation is firstly proposed, and then some properties of two types of approximation operators are studied. Afterwards, for two different kinds of approximation operators, we introduce two roughness measure methods of the same vague set and discuss a property. Finally, an example is given to illustrate how to calculate the rough approximations and roughness measure of a vague set using the β-(complement) product between two fuzzy matrixes. The results show that the proposed rough approximations and roughness measure of a vague set in fuzzy environment are reasonable. 相似文献
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在模糊集合的公理化定义及其直积的基础上,提出基本模糊点的模糊邻域算子概念。用模糊邻域算子来定义模糊集的上近似和下近似。可以用模糊集的上、下近似来刻画模糊关系的自反性、对称性和传递性等性质。在模糊粗糙集的模糊邻域算子定义下,模糊粗糙集与粗糙模糊集可以统一起来。 相似文献