Weighted trapezoidal approximation-preserving cores of a fuzzy number

Recently, various researchers have proved that approximations of fuzzy numbers may fail to be fuzzy numbers. In this contribution, we suggest a new weighted trapezoidal approximation of an arbitrary fuzzy number, which preserves its cores. We prove that the weighted trapezoidal approximation-preserving core is always a fuzzy number. We then discuss properties of the approximation strategy including translation invariance, scale invariance identity and continuity. The advantage is that the method presented here is simpler than other methods computationally.     

多属性群决策的直觉梯形模糊数法

采用直觉梯形模糊数刻画专家的评价信息,提出一种新的多属性群决策方法.定义了直觉梯形模糊数的期望值、预期得分、有序加权集成算子和混合集成算子;建立了基于直觉梯形模糊数的多属性群决策模型;通过混合集成算子得到方案的群体综合评估值,根据期望值和预期得分给出群决策结果.实例分析验证了所提出方法的有效性.     

梯形模糊互反判断矩阵的一致性及修正

研究具有严格偏好关系的梯形模糊互反判断矩阵满意一致性的判定及其修正方法。首先,将梯形模糊互反判断矩阵转化为判断矩阵和排列矩阵;然后,根据梯形模糊互反判断矩阵的排列矩阵来判定是否具有满意一致性;基于梯形模糊数的类质心,给出将排列矩阵转化成上三角矩阵的方法,从而实现方案的排序;最后,通过项目评估问题验证了所提出方法的实用性。     

模糊语言下的梯形模糊数心态指标群决策方法

在模糊语言下,提出了梯形模糊数心态指标的群决策方法。在属性权系数和决策者权系数信息都不完全的情况下,引入心态指标,将模糊语言的梯形模糊数决策矩阵转化为带心态指标的决策矩阵;利用决策的不完全信息构造Fuzzy线性规划,分别求解出属性权重和决策者权重;对决策者的心态指标进行集成得到群体风险态度,模糊集成群体风险态度与方案的群体评价值,得到整个方案集的排序。选取实例说明该方法的有效性、可行性和可操作性。     

基于分式规划的区间直觉梯形模糊数多属性决策方法

针对属性值为区间梯形直觉模糊且属性权重为区间数的多属性决策问题,提出一种基于分式规划的决策方法.定义了区间梯形直觉模糊数的Hamming距离和Euclidean距离,采用优劣解距离法构建了相对贴近度的非线性分式规划模型,并通过Charnes and Cooper变换转化为线性规划模型求解,得到各方案相对贴近度的区间数,进而提出了决策方法.数值算例分析验证了所提出方法的有效性.     

基于区间梯形二型犹豫模糊数的多准则决策方法

针对准则权重不完全的犹豫模糊多准则决策问题,提出基于区间梯形二型犹豫模糊数的决策方法.首先,给出区间梯形二型犹豫模糊数,根据几何面积法定义区间梯形二型犹豫模糊数的可能度和差异度;然后,利用差异度和离差最大化模型得到各准则权重,基于TOPSIS思想得到各方案的综合贴近度,并对方案进行排序;最后,通过算例分析和对比分析验证了所提出方法的可行性和有效性.     

基于区间直觉梯形模糊数的多属性决策方法

对区间直觉梯形模糊数进行研究．探讨了区间直觉梯形模糊数的运算法则及其性质;给出了区间直觉梯形模糊数的加权算术平均和加权几何平均算子,定义了区间直觉梯形模糊数的得分函数和精确函数,进而给出其排序方法;建立了基于区间直觉梯形模糊数的多属性决策模型,并提出了相应的决策方法．实例分析验证了所提出方法的有效性．     

三角模糊数多属性决策在软件项目风险评估中应用

风险评估是软件项目风险管理的基础。基于软件项目风险评估目标及相关文献分析,构建了风险评估的准则体系,并将三角模糊数多属性决策方法应用于软件项目风险评估中。通过实例说明了该方法运用于软件项目风险评估的具体过程,并验证了其合理性和可操作性。     

基于前景ITFNCI 算子的群体MULTIMOORA决策方法

利用进一步完善的直觉梯形模糊数运算法则,提出基于模糊测度和Choquet积分的直觉梯形模糊数的信息集成算子,并证明了该集成算子的相关性质.根据前景理论定义直觉梯形模糊前景效应和前景价值函数,构造前景ITFNCI算子.针对多方参与且决策者信息关联的多属性群决策问题,利用前景ITFNCI算子集结群体直觉梯形前景价值函数,进而采用MULTIMOORA理论进行方案比选,基于优势理论获得方案的综合排序以确定最优方案.案例分析表明了所提出方法的可行性和有效性.     

Fuzzy system reliability evaluation using time-dependent intuitionistic fuzzy set

In general, fuzzy sets are used to analyse the system reliability. In this article, the concept of fuzzy set is extended by the idea of intuitionistic fuzzy set (IFS) and a new general procedure is proposed to construct the membership and non-membership functions of the fuzzy reliability using time-dependent IFS. Here, failure rate function of the system is represented by a triangular intuitionistic fuzzy number (IFN). Also, using proposed approach, membership and non-membership functions of fuzzy reliability of series and parallel systems are constructed, where the failure rate of each component is taken as a time-dependent triangular IFN. The major advantage of using IFS over fuzzy sets is that IFS separate the positive and negative evidences for membership of an element in the set. Numerical examples are given to illustrate the proposed approach.     

动态模糊综合评判在教学质量评价中的应用

根据教学质量评价的特点,针对传统模糊综合评判的不足,主要是针对其评价结果不能很好地反映评价目标的动态发展趋势的问题,提出了基于动态模糊理论的教学质量综合评判方法,给出了一种基于群体可拓层次分析法的动态模糊权重确定方法和动态模糊关系矩阵的确定方法,并结合一个具体的评价实例,验证了所提方法的科学性和客观性。     

Discontinuity of the trapezoidal fuzzy number-valued operators preserving core

We prove that any trapezoidal fuzzy number-valued operator preserving core is discontinuous with respect to any weighted metric on the space of fuzzy numbers. As an application, we obtain the discontinuity of the weighted trapezoidal approximation operator preserving core.     

Approximations of fuzzy numbers by trapezoidal fuzzy numbers preserving the ambiguity and value

Value and ambiguity are two parameters which were introduced to represent fuzzy numbers. In this paper, we find the nearest trapezoidal approximation and the nearest symmetric trapezoidal approximation to a given fuzzy number, with respect to the average Euclidean distance, preserving the value and ambiguity. To avoid the laborious calculus associated with the Karush–Kuhn–Tucker theorem, the working tool in some recent papers, a less sophisticated method is proposed. Algorithms for computing the approximations, many examples, proofs of continuity and two applications to ranking of fuzzy numbers and estimations of the defect of additivity for approximations are given.     

基于模糊综合评判的入侵检测模型的应用与研究

针对现有入侵检测技术所存在的入侵行为特征描述困难、边界锐化、误报率和漏报率高等问题,结合模糊数学和层次分析法,提出了一种综合评判入侵检测系统性能的新方法:一方面采用改进后的层次分析法和熵值法相结合的综合分析赋权法来配置和调整权重;另一方面采用基于梯型函数的非模糊统计方法和遗传算法来建立最优的隶属函数,把评估的主观因素限制在很小的范围内,提高了评判结果的准确度和可信度.实验结果表明,该方法与Snort方法相比能明显的减少误报率和漏报率.     

形式化规范在软件可靠性早期估计中的应用研究

随着软件的广泛应用,特别是软件在尖端领域的应用,软件可靠性成为一个非常重要的问题。形式化规范在软件可靠性研究中能够起到的作用是多方面的。本文针对非形式化统计使用测试的不足,结合已有的早期可靠性估计方法,设计了优化算法,并提出了即使在设计中采用了形式化规范仍然需要测试的结论。     

Sensor dynamic reliability evaluation based on evidence theory and intuitionistic fuzzy sets

This paper presents a new method for sensor dynamic reliability evaluation based on evidence theory and intuitionistic fuzzy sets when the prior knowledge is unknown. The dynamic reliability of sensors is evaluated based on supporting degree between basic probability assignments (BPAs) provided by sensors. First, the concept of asymmetric supporting degree is proposed. By transforming BPAs to intuitionistic fuzzy sets, supporting degree between BPAs is calculated based on intuitionistic fuzzy operations and similarity measure. Then the relationship between dynamic reliability and supporting degree is analyzed. The process of dynamic reliability evaluation is proposed. Finally, the proposed dynamic reliability evaluation is applied to evidence combination. A new evidence combination rule is proposed based on evidence discounting operation and Dempster’s rule. Comparative analysis on the performance of the proposed reliability evaluation method and evidence combination rule is carried out based on numerical examples. The proposed method for data fusion is also applied in target recognition to show its feasibility and validity.     

Efficient computer-based scheme for improving the reliability performance of power substations

A computational methodology for improving the reliability performance of power substations is presented. Fault identification techniques have been developed to detect electrical component failures very early. The available operating actions following a detected component failure are deduced. A supply reliability index of substation load-points is introduced and evaluated. The application of the developed methodology on a typical Hellenic high-voltage substation is also presented.     

联系数的物元模型在综合评价中应用

事物综合评价一般采用定性与定量相结合得方法.采用联系数来描述事物特征的不确定量值,介绍了联系数得概念和运算准则,建立了联系数的物元模型,将由评价者自身的差异给评价量值带来的差异视为权重,在此基础上提出了联系数物元模型的综合评价方法,并给出了联系数物元模型在评价决策领域的应用案例.案例证明联系数物元模型客观合理,应用方便,可用于解决综合评价问题.     

模糊层次分析法在高校教师评价中的应用

针对高校教师评价问题中隐性工作难评价的问题,采用模糊层次分析模型对教师评价问题进行研究。在指标层中划分量化指标和隐性指标两部分。量化指标的计算结合分值和模糊互补判断矩阵,隐性指标则采用模糊互补判断矩阵和调查表。目标层是结合量化指标和隐性指标做出结论,解决了教师隐性工作评估问题。