论模糊概念的度量

模糊度和模糊相似度是模糊集合中模糊概念度量最常用的两种方法。根据模糊度定义,提出了几种实用方便的模糊度公式,并分析了文[3]中新模糊度公式的不正确性;同时根据模糊贴近度定义,提出了一种贴近度公式。这些新公式的引入,在模式识别等实际应用中起着重要的作用。     

ON MEASURES OF FUZZINESS AND FUZZY COMPLEMENTS

An axiomatic framework for formalizing the most general class of fuzzy complements is introduced in this paper. It is then used for investigating a general class of measures of fuzziness based on the view that the degree of fuzziness of a fuzzy set should characterize the lack of distinction between the set and its complement. It is shown that the various measures of fuzziness described previously in the literature are special cases of this general class. A class of so-called distance-based measures of fuzziness is also introduced. These measures are described in terms of the notion of an aggregation function of differences between the membership grades characterizing a fuzzy set and those of its complement. It is shown that the class of distance-based measures is equal to the class of general measures of fuzziness. It is also shown that, given a particular fuzzy complement, aggregation functions which differ only in a multiplication constant represent the same measure of fuzziness.     

Hesitant fuzzy information measures and their applications in multi-criteria decision making

Hesitant fuzzy set (HFS) is a powerful decision tool to express uncertain information more flexibly and comprehensively. The aim of this paper is to propose more reasonable information measures for HFSs in comparison with the existing ones. First, a series of distance measures is suggested for hesitant fuzzy element and hesitant fuzzy sets. These measures are directly calculated from hesitant fuzzy elements without judging the decision-makers’ risk preference and adding any values into the hesitant fuzzy element with the smaller number of elements. Then, some similarity and entropy measures are proposed based on the transforming relationship among the information measures. Additionally, based on the proposed information measures, a TOPSIS method for hesitant fuzzy information is provided. Finally, some numerical examples are used in order to illustrate the proposed decision method and a comparative analysis is made to demonstrate that the suggested measures are more objective and feasible in certain cases.     

新的模糊粗糙集的模糊性度量方法

研究了模糊粗糙集的模糊性度量方法。首先从模糊集支集的角度,给出了一般模糊关系下模糊集的粗糙隶属函数;在此基础上,设计了一种合理的模糊粗糙集的模糊性度量方法,并对其相关性质进行了详细的讨论。     

Divergence and fuzziness measures

In an axiomatic way a divergence between fuzzy sets is introduced which extends the symmetric difference between crisp sets. Any fuzzy measure of the divergence between two fuzzy sets weighs their “distance”. The distance between a fuzzy set and the family of crisp sets is fuzziness measure.     

Inclusion measures,similarity measures,and the fuzziness of fuzzy sets and their relations

The inclusion measure, the similarity measure, and the fuzziness of fuzzy sets are three important measures in fuzzy set theory. In this article, we investigate the relations among inclusion measures, similarity measures, and the fuzziness of fuzzy sets, prove eight theorems that inclusion measures, similarity measures, and the fuzziness of fuzzy sets can be transformed by each other based on their axiomatic definitions, and propose some new formulas to calculate inclusion measures, similarity measures, and the fuzziness of fuzzy sets. These results can be applied in many fields, such as pattern recognition, image processing, fuzzy neural networks, fuzzy reasoning, and fuzzy control. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 639–653, 2006.     

Gradual elements in a fuzzy set

The notion of a fuzzy set stems from considering sets where, in the words of Zadeh, the “transition from non-membership to membership is gradual rather than abrupt”. This paper introduces a new concept in fuzzy set theory, that of a gradual element. It embodies the idea of fuzziness only, thus contributing to the distinction between fuzziness and imprecision. A gradual element is to an element of a set what a fuzzy set is to a set. A gradual element is as precise as an element, but the former is flexible while the latter is fixed. The gradual nature of an element may express the idea that the choice of this element depends on a parameter expressing some relevance or describing some concept. Applications of this notion to fuzzy cardinality, fuzzy interval analysis, fuzzy optimization, and defuzzification principles are outlined.     

粗糙集的不确定性度量准则

针对现有粗糙集不确定性度量中有些定义在某种情况下并不合理,给出粗糙集不确定性度量的基本准则,证明除二次模糊度外其它几种不确定性度量都是满足基本准则的不确定性度量。由于满足基本准则的不确定性度量仍然可能存在不足,文中对基本准则中的单调性进行进一步限制,提出不确定性度量的扩展准则,并证明模糊熵和修正模糊度是满足扩展准则的不确定性度量,而粗糙度、粗糙熵和线性模糊度都不满足扩展准则。这些结论为已有的不确定性度量的合理性(或不合理性)提供理论说明,也为设计新的不确定性度量方法提供依据。     

Multiple attribute group decision-making based on order-α divergence and entropy measures under q-rung orthopair fuzzy environment

The q-rung orthopair fuzzy set (^qROPFS), proposed by Yager, is a more effective and proficient tool to represent uncertain or vague information in real-life situations. Divergence and entropy are two important measures, which have been extensively studied in different information environments, including fuzzy, intuitionistic fuzzy, interval-valued fuzzy, and Pythagorean fuzzy. In the present communication, we study the divergence and entropy measures under the q-rung orthopair fuzzy environment. First, the work defines two new order-α divergence measures for ^qROPFSs to quantify the information of discrimination between two ^qROPFSs. We also examine several mathematical properties associated with order-α ^qROPF divergence measures in detail. Second, the paper introduces two new parametric entropy functions called “order-α ^qROPF entropy measures” to measure the degree of fuzziness associated with a ^qROPFS. We show that the proposed order-α divergence and entropy measures include several existing divergence and entropy measures as their particular cases. Further, the paper develops a new decision-making approach to solve multiple attribute group decision-making problems under the ^qROPF environment where the information about the attribute weights is completely unknown or partially known. Finally, an example of selecting the best enterprise resource planning system is provided to illustrate the decision-making steps and effectiveness of the proposed approach.     

犹豫直觉模糊集的知识测度及其应用

犹豫直觉模糊集集成了直觉模糊集与犹豫模糊集的优点,能够更好地处理决策者偏好不一致时的不确定性问题。通过考虑决策者提供信息的犹豫性与模糊性,给出了犹豫直觉模糊集上知识测度的公理化定义,并且构建出犹豫直觉模糊集上一类含参知识测度,这类知识测度可以有效地刻画犹豫直觉模糊集所包含的信息量和决策者的态度特征。接下来,基于对该类知识测度中的参数进行讨论,得到一系列代表决策者不同态度特征的知识测度,进一步验证了知识测度与决策者态度系数的变化成正比。最后,基于犹豫直觉模糊集的知识测度提出多属性群决策方法,并将此方法应用于某互联网公司的空调安装公司选择的案例中,证明了所提出的知识测度具有有效性与实用性。     

Uncertainty measures for interval type-2 fuzzy sets

Fuzziness (entropy) is a commonly used measure of uncertainty for type-1 fuzzy sets. For interval type-2 fuzzy sets (IT2 FSs), centroid, cardinality, fuzziness, variance and skewness are all measures of uncertainties. The centroid of an IT2 FS has been defined by Karnik and Mendel. In this paper, the other four concepts are defined. All definitions use a Representation Theorem for IT2 FSs. Formulas for computing the cardinality, fuzziness, variance and skewness of an IT2 FS are derived. These definitions should be useful in IT2 fuzzy logic systems design using the principles of uncertainty, and in measuring the similarity between two IT2 FSs.     

Entropy of interval-valued fuzzy sets based on distance and its relationship with similarity measure

This article proposes a new axiomatic definition of entropy of interval-valued fuzzy sets (IVFSs) and discusses its relation with similarity measure. First, we propose an axiomatic definition of entropy for IVFS based on distance which is consistent with the axiomatic definition of entropy of a fuzzy set introduced by De Luca, Termini and Liu. Next, some formulae are derived to calculate this kind of entropy. Furthermore we investigate the relationship between entropy and similarity measure of IVFSs and prove that similarity measure can be transformed by entropy. Finally, a numerical example is given to show that the proposed entropy measures are more reasonable and reliable for representing the degree of fuzziness of an IVFS.     

A note on measuring fuzziness for intuitionistic and interval-valued fuzzy sets

We first review the concept of fuzziness provided by DeLuca and Termini, and the view of fuzziness as related to the lack of distinction between a set and its negation. We then suggest a measure of fuzziness for intuitionistic fuzzy sets. We show that this measure satisfies the required conditions for an intuitionistic measure of fuzziness. We then take advantage of the connection between intuitionistic and interval-valued membership grades to transfer the intuitionistic measure of fuzziness to one suitable for interval-valued fizzy sets.     

Divergence-based cross entropy and uncertainty measures of Atanassov’s intuitionistic fuzzy sets with their application in decision making

The uncertainty measure of Atanassov’s intuitionistic fuzzy sets (AIFSs) is important for information discrimination under intuitionistic fuzzy environment. Although many entropy measures and knowledge measures haven been proposed to depict uncertainty of AIFSs, how to measure the uncertainty of AIFSs is still an open topic. The relation between uncertainty and other measures like entropy measures, fuzziness and intuitionism is not clear. This paper introduces uncertainty measures by using new defined divergence-based cross entropy measure of AIFSs. Axiomatic properties of the developed uncertainty measure are analysis, together with the monotony property of uncertainty degree with respect to fuzziness and intuitionism. To adjust the contribution of fuzzy entropy and intuitionistic entropy on the total uncertainty, the proposed cross entropy and uncertainty measures are parameterized. Numerical examples indicate the effectiveness and agility of the biparametric uncertainty measure in quantifying uncertainty degree. Then we apply the cross entropy and uncertainty measures into an optimal model to determine attribute weights in multi-attribute group decision making (MAGDM) problems. A new method for intuitionistic fuzzy MAGDM problems is proposed to show the efficiency of proposed measures in applications. It is demonstrated by application examples that the proposed measures can get reasonable results coinciding with other existing methods.     

Uncertainty measures for probabilistic hesitant fuzzy sets in multiple criteria decision making

This contribution reviews critically the existing entropy measures for probabilistic hesitant fuzzy sets (PHFSs), and demonstrates that these entropy measures fail to effectively distinguish a variety of different PHFSs in some cases. In the sequel, we develop a new axiomatic framework of entropy measures for probabilistic hesitant fuzzy elements (PHFEs) by considering two facets of uncertainty associated with PHFEs which are known as fuzziness and nonspecificity. Respect to each kind of uncertainty, a number of formulae are derived to permit flexible selection of PHFE entropy measures. Moreover, based on the proposed PHFE entropy measures, we introduce some entropy-based distance measures which are used in the portion of comparative analysis. Eventually, the proposed PHFE entropy measures and PHFE entropy-based distance measures are applied to decision making in the strategy initiatives where their reliability and effectiveness are verified.     

‘Useful’ fuzzy measures of information,integrated ambiguity and directed divergence

In the present paper, a new concept of ‘useful’ fuzzy information, based on utility, is introduced by considering the uncertainties of fuzziness and probabilities of random events. A ‘useful’ fuzzy measure of integrated ambiguity is obtained by integration of fuzzy and probabilistic uncertainties with utility. A new ‘useful’ measure of fuzzy-directed divergence of a fuzzy set from another fuzzy set is proposed and its validity proved. Finally, the constrained optimisation of ‘useful’ fuzzy entropy and ‘useful’ fuzzy-directed divergence is studied.     

粗糙集不确定性度量的矩阵运算

粗糙集的不确定性度量是粗糙集理论的重要研究内容之一。结合模糊理论和粒计算理论改进了粗糙集的不确定性度量方法。通过集合的相对知识粒度及边界熵给出了粗糙集的粗糙性度量函数与模糊性度量函数,随着近似空间知识粒的细分,粗糙集的粗糙度与模糊度均满足单调递减的性质。利用矩阵理论提出了易于实现的粗糙性度量与模糊性度量的矩阵算法。     

Dual concepts in fuzzy theory: Entropy and knowledge measure

Entropy in a fuzzy set measures the amount of ambiguity/imprecision present in the fuzzy set. In this paper, we introduce a knowledge measure of a fuzzy set and its generalization (accuracy measure). The knowledge measure may be considered as a dual measure of fuzzy entropy. We also investigate the effectiveness and application of the proposed knowledge measure in multiple attribute decision making. Furthermore, we provide a result for obtaining a class of knowledge measure. We also prove a general method for obtaining a knowledge measure using accuracy measure. Among some suggested implications of the proposed fuzzy accuracy measure, we demonstrate the application of fuzzy accuracy measure in image thresholding.     

An improved medical image enhancement scheme using Type II fuzzy set

A contrast enhancement of medical images using Type II fuzzy set theory is suggested. Fuzzy set theory considers uncertainty in the form of membership function but to have better information on uncertainty on the membership function, Type II fuzzy set is considered. Type II fuzzy set considers fuzziness in the membership function. Hamacher T co norm is used as an aggregation operator to form a new membership function using the upper and lower membership function of Type II fuzzy set. The image with the new membership function is an enhanced image. As medical images contain lot of uncertainties, Type II fuzzy set may be a good tool for medical image analysis. To show the effectiveness of the proposed method, the results are compared with fuzzy, intuitionistic fuzzy, and existing Type II fuzzy methods. Experiments on several images show that the proposed Type II fuzzy method performs better than the existing methods. To show the advantage of the proposed enhancement method, detection or extraction of abnormal lesions or blood vessels has been carried out on enhanced images of all the methods. It is observed that the segmented results on the proposed enhanced images are better.