基于AHP-FCE模型的岩溶地面塌陷灾害易发程度分区评价

岩溶地面塌陷灾害具有隐蔽性、突发性、不均一性以及多因素性等特点,为了能够真实准确地进行岩溶地面塌陷灾害易发程度分区,本文基于层次分析法和模糊数学理论,建立了层次分析-模糊综合评判(AHP-FCE)模型.在全面分析岩溶地面塌陷的致灾因素后,选取了6个条件层,共15个影响因子,并按照重要程度确定权重,通过正态函数和梯形函数...     

OBE算法对误差界低估的鲁棒性

研究了具有未知但有界(UBB)误差系统辨识的最优定界椭球(OBE)算法对误差界低估的鲁棒性.证明了在一定的条件下,即使误差界低估,任何OBE算法都能保持其收敛性.这一结论可用于具有UBB误差的实际系统参数估计中,以期获得不太保守的结果.     

多元模糊模式识别在钢碳化物评级中的应用

应用Fuzzy集理论研究了如何用隶属函数来描述合金工具钢碳化物的不均匀性,提出一种评定碳化物级别的方法,并进行了计算检验.     

超高层建筑结构选型技术研究

对于超高层建筑的设计,往往有多个可供选择的结构方案。为了能够科学快速地选择出建筑功能、结构性能、抗震性能和经济性能等综合指标都能达到最满意的结构方案,本文基于模糊数学和层次分析法的原理采用模糊层次综合优选法来确定超高层建筑的结构方案。该法首先将影响超高层建筑结构方案选择的因素划分为包括目标层、准则层和指标层三部分的递阶层次结构,其中准则层因素分为静力性能、多遇地震下抗震性能和经济性能三类,指标层因素又细分为21个指标;然后给出了各指标的隶属函数,从而求出各指标的隶属度和指标层相对于准则层的权重集;最后根据模糊矩阵合成运算得出最终的综合评判结果。该法既避免反复试算造成的人力、物力资源的浪费,又避免了专家个人能力局限性的制约,具有重要的工程价值。     

隶属函数对模糊控制性能的作用与影响

从理论和仿真真实验两个方面分析了隶属函数分布形状对模糊控制性能的作用和影响,总结出隶属函数选取的原则。     

模糊支持向量机在汽轮机故障诊断中的应用

阐述了模糊支持向量机的原理。考虑到各类样本的不同影响,在基于风险的基础上,通过确定各个样本的模糊隶属度,引入模糊支持向量机的概念,将这一理论应用于汽轮机减速箱的故障诊断中,使一类样本点中只包含正常样本。实验结果表明了该方法的可行性与有效性。     

基于故障全信息的自适应模糊融合选线技术

小电流接地系统发生单相接地故障时,由于故障信号微弱、运行方式变化、故障类型复杂等因素的影响,小电流接地系统故障选线一直是困扰现场的一个技术难题。综合运用故障后零序电压电流的全信息,基于信息融合技术,利用群体比幅比相法、五次谐波比相法、小波分析法进行故障后的稳态及暂态信息进行综合分析,采用模糊理论构造出了各方法判据的隶属度函数以及权系数的隶属度函数,提高选线方法的自适应能力,提高选线的成功率。在PSCAD/EMTDC中搭建了单端辐射状配电网模型,仿真计算结果验证了该方法的高可靠性以及适用性。     

Fuzzy Genetic Algorithm Approach for the Optimal Placement of Flexible AC Transmission Systems Devices in a Power System

Abstract—This article presents a novel approach for optimal flexible AC transmission systems devices planning in an interconnected power system under different loading conditions. The static VAR compensator and thyristor-controlled series capacitor are two types of flexible AC transmission systems devices considered for optimal power system operation. In the proposed approach, a fuzzy membership function is used to determine weak nodes in the power system for the placement of static VAR compensators as a flexible AC transmission systems device. The thyristor-controlled series capacitor is the other type of flexible AC transmission systems devices for which its positions are determined by the reactive power flow in lines. The genetic algorithm is used for the optimal setting of the power system variables, including flexible AC transmission systems devices. The proposed technique is compared with other optimization methods using different globally accepted evolutionary algorithms where the nodes or point of VAR compensation is determined by eigenvalue analysis, and the amount of flexible AC transmission systems devices is determined by evolutionary techniques, such as the genetic algorithm, differential evolution, and particle swarm optimization. The superiority of the proposed fuzzy-based optimization approach is established by the results and comparative analysis with other methods.     

Condition evaluation for existing reinforced concrete bridge superstructure using fuzzy clustering improved by particle swarm optimisation

Condition evaluations of old bridges are necessary for determining their health states and providing priority levels of maintenance. In this paper, a novel condition evaluation approach for reinforced concrete (RC) bridge superstructure is presented based on fuzzy c-mean clustering optimised by particle swarm optimisation (FCM-PSO) algorithm. It is equipped with the advantages of PSO algorithm in global optimisation and FCM algorithm in convergence acceleration, which greatly improves the effectiveness of clustering. Using this methodology, a reliable evaluation index system and a number of training samples from field-measured data of existing old bridges are prerequisites. In addition, the optimal cluster number for training samples can be determined by Xie–Beni validity evaluation index. Subsequently, condition grades and corresponding cluster centres can be determined based on the calculation of cluster centres and membership matrix for training samples. On the above basis, bridge conditions of testing samples can be evaluated based on the fuzzy membership to the cluster centres of condition grades. A case study was carried out to verify the feasibility and effectiveness of the proposed FCM-PSO method. Evaluation results reveal that the proposed method can effectively reduce the influence of subjective factors and will be favourable for condition evaluation of existing RC bridges.     

模糊综合分析法在信用评级中的应用研究

从模糊综合评价法的含义出发,列举了该方法具有考察指标变化非线性影响等特点,探讨了在运用模糊综合评级中遇到的两个重要问题——指标权重确定方法和指标隶属度的计算方法,列举和比较了可供选择的多种方法,说明了如何将模糊综合评价法运用到信用评级中,并且通过案例说明了模糊综合评价法的应用,选择上海市贷款企业信用等级评定标准中所选择的指标体系和采取的指标权重,对于某受评单位,运用指数衰减法建立了模糊评级矩阵,并进行了信用评级。通过模糊综合信用评级,可以有效地避免评级中的过于主观性,有力提高了信用评级的科学性和准确度。