共查询到17条相似文献,搜索用时 89 毫秒
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目的是结合精度与程度,探索新的粗糙集拓展模型.从程度与精度的逻辑差运算出发,定义了程度与精度的逻辑差粗糙集模型.模型中,通过变精度近似与程度近似的转化公式,研究了程度与精度的逻辑差近似算子,并得到了近似算子的幂作用等性质.用程度与精度的逻辑差粗糙集模型拓展了程度粗糙集模型、经典粗糙集模型,并在这些模型中得到了近似算子幂作用的相应性质. 相似文献
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目的是探讨精度与程度的复合,建立并研究新的粗糙集拓展模型.基于程度与精度的逻辑差需求,提出了程度下近似算子与变精度上近似算子的差运算模型,得到了程度下近似算子与变精度上近似算子的差运算的宏观本质、精确描述与基本性质.并用一个医疗实例说明了模型的意义和应用.程度下近似算子与变精度上近似算子的差运算模型,部分的拓展了程度粗糙集模型和经典粗糙集模型. 相似文献
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在变精度概率粗糙集模型和相容粗糙集模型的基础上,探索粗糙集模型的扩展问题,提出了变精度概率相容粗糙集模型,并探讨了新模型上下近似算子的基本性质、数字特征以及与其他粗糙集模型之间的关系. 相似文献
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引入集对分析概念,提出了一种基于集对分析下的变精度Bayesian粗糙集模型,这就将经典粗糙集模型和变精度Bayesian粗糙集模型推广到了不完备信息系统,并且得到了该模型的上、下近似的一些性质.最后,给出了与该模型定义等价的一个定理. 相似文献
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不完备信息系统中目前有多种扩充,如基于容差关系的扩充、基于相似关系的扩充等等,但是这些扩充都各自存在局限性。针对这些局限性,引入相对分类错误率的概念,提出了一种基于限制容差关系下的集对变精度粗糙集模型。这就将经典的粗糙集模型和限制容差关系下的集对粗糙集模型进行了推广。然后,讨论了该模型上、下近似算子的一些性质。最后,通过一个具体例子,说明了该模型在不完备信息系统中处理模糊和不确定性知识是可行、有效的。 相似文献
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粗糙集研究中的模糊集方法 总被引:10,自引:0,他引:10
通过粗糙隶属度函数 ,将粗集理论与模糊理论联系起来 ,建立一种粗集理论与模糊理论的关系。利用这种关系 ,引入置信水平 ,将经典粗糙集模型进行了推广 ,并讨论等价关系变化前后集合上下近似之间的关系。 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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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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Monotonic Variable Consistency Rough Set Approaches 总被引:2,自引:0,他引:2
Jerzy Baszczyski Salvatore Greco Roman Sowiski Marcin Szel
g 《International Journal of Approximate Reasoning》2009,50(7):979
We consider probabilistic rough set approaches based on different versions of the definition of rough approximation of a set. In these versions, consistency measures are used to control assignment of objects to lower and upper approximations. Inspired by some basic properties of rough sets, we find it reasonable to require from these measures several properties of monotonicity. We consider three types of monotonicity properties: monotonicity with respect to the set of attributes, monotonicity with respect to the set of objects, and monotonicity with respect to the dominance relation. We show that consistency measures used so far in the definition of rough approximation lack some of these monotonicity properties. This observation led us to propose new measures within two kinds of rough set approaches: Variable Consistency Indiscernibility-based Rough Set Approaches (VC-IRSA) and Variable Consistency Dominance-based Rough Set Approaches (VC-DRSA). We investigate properties of these approaches and compare them to previously proposed Variable Precision Rough Set (VPRS) model, Rough Bayesian (RB) model, and previous versions of VC-DRSA. 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