Discrete Variable Structural Optimization based on Multidirectional Fuzzy Genetic Algorithm

Round method is the common method for discrete variable optimization in optimal design of complex mechanical structures;however,it has some disadvantages such as poor precision,simple model and lacking of working conditions＇ description,etc.To solve these problems,a new model is constructed by defining parameterized fuzzy entropy,and the rationality of parameterized fuzzy entropy is verified.And a new multidirectional searching algorithm is further put forward,which takes information of actual working conditions into consideration and has a powerful local searching capability.Then this new algorithm is combined with the GA by the fuzzy clustering algorithm（FCA）.With the application of FCA,the optimal solution can be effectively filtered so as to retain the diversity and the elite of the optimal solution,and avoid the structural re-analysis phenomenon between the two algorithms.The structure design of a high pressure bypass-valve body is used as an example to make a structural optimization by the proposed HGA and finite element method（FEM）,respectively.The comparison result shows that the improved HGA fully considers the characteristic of discrete variable and information of working conditions,and is more suitable to the optimal problems with complex working conditions.Meanwhile,the research provides a new approach for discrete variable structure optimization problems.

Integrated classification method of tight sandstone reservoir based on principal component analysise simulated annealing genetic algorithmefuzzy cluster means

In this research,an integrated classification method based on principal component analysis-simulated annealing genetic algorithm-fuzzy cluster means(PCA-SAGA-FCM)was proposed for the unsupervised classification of tight sandstone reservoirs which lack the prior information and core experiments.A variety of evaluation parameters were selected,including lithology characteristic parameters,poro-permeability quality characteristic parameters,engineering quality characteristic parameters,and pore structure characteristic parameters.The PCA was used to reduce the dimension of the evaluation pa-rameters,and the low-dimensional data was used as input.The unsupervised reservoir classification of tight sandstone reservoir was carried out by the SAGA-FCM,the characteristics of reservoir at different categories were analyzed and compared with the lithological profiles.The analysis results of numerical simulation and actual logging data show that:1)compared with FCM algorithm,SAGA-FCM has stronger stability and higher accuracy;2)the proposed method can cluster the reservoir flexibly and effectively according to the degree of membership;3)the results of reservoir integrated classification match well with the lithologic profle,which demonstrates the reliability of the classification method.

Fuzzy Fruit Fly Optimized Node Quality-Based Clustering Algorithm for Network Load Balancing

Recently,the fundamental problem with Hybrid Mobile Ad-hoc Net-works(H-MANETs)is tofind a suitable and secure way of balancing the load through Internet gateways.Moreover,the selection of the gateway and overload of the network results in packet loss and Delay(DL).For optimal performance,it is important to load balance between different gateways.As a result,a stable load balancing procedure is implemented,which selects gateways based on Fuzzy Logic(FL)and increases the efficiency of the network.In this case,since gate-ways are selected based on the number of nodes,the Energy Consumption(EC)was high.This paper presents a novel Node Quality-based Clustering Algo-rithm(NQCA)based on Fuzzy-Genetic for Cluster Head and Gateway Selection(FGCHGS).This algorithm combines NQCA with the Improved Weighted Clus-tering Algorithm(IWCA).The NQCA algorithm divides the network into clusters based upon node priority,transmission range,and neighbourfidelity.In addition,the simulation results tend to evaluate the performance effectiveness of the FFFCHGS algorithm in terms of EC,packet loss rate(PLR),etc.

Improved method for the feature extraction of laser scanner using genetic clustering

Feature extraction of range images provided by ranging sensor is a key issue of pattern recognition. To automatically extract the environmental feature sensed by a 2D ranging sensor laser scanner, an improved method based on genetic clustering VGA-clustering is presented. By integrating the spatial neighbouring information of range data into fuzzy clustering algorithm, a weighted fuzzy clustering algorithm （WFCA） instead of standard clustering algorithm is introduced to realize feature extraction of laser scanner. Aimed at the unknown clustering number in advance, several validation index functions are used to estimate the validity of different clustering algorithms and one validation index is selected as the fitness function of genetic algorithm so as to determine the accurate clustering number automatically. At the same time, an improved genetic algorithm IVGA on the basis of VGA is proposed to solve the local optimum of clustering algorithm, which is implemented by increasing the population diversity and improving the genetic operators of elitist rule to enhance the local search capacity and to quicken the convergence speed. By the comparison with other algorithms, the effectiveness of the algorithm introduced is demonstrated.

Fault Diagnosis Model Based on Fuzzy Support Vector Machine Combined with Weighted Fuzzy Clustering

A fault diagnosis model is proposed based on fuzzy support vector machine (FSVM) combined with fuzzy clustering (FC).Considering the relationship between the sample point and non-self class,FC algorithm is applied to generate fuzzy memberships.In the algorithm,sample weights based on a distribution density function of data point and genetic algorithm (GA) are introduced to enhance the performance of FC.Then a multi-class FSVM with radial basis function kernel is established according to directed acyclic graph algorithm,the penalty factor and kernel parameter of which are optimized by GA.Finally,the model is executed for multi-class fault diagnosis of rolling element bearings.The results show that the presented model achieves high performances both in identifying fault types and fault degrees.The performance comparisons of the presented model with SVM and distance-based FSVM for noisy case demonstrate the capacity of dealing with noise and generalization.

Recognition of Spontaneous Combustion in Coal Mines Based on Genetic Clustering

Spontaneous combustion is one of the greatest disasters in coal mines. Early recognition is important because it may be a potential inducement for other coalmine accidents. However, early recognition is difficult because of the complexity of different coal mines. Fuzzy clustering has been proposed to incorporate the uncertainty of spontaneous combustion in coal mines and it can give a clear degree of classification of combustion. Because FCM clustering tends to become trapped in local minima, a new approach of fuzzy c-means clustering based on a genetic algorithm is there- fore proposed. Genetic algorithm is capable of locating optimal or near optimal solutions to difficult problems. It can be applied in many fields without first obtaining detailed knowledge about correlation. It is helpful in improving the effec- tiveness of fuzzy clustering in detecting spontaneous combustion. The effectiveness of the method is demonstrated by means of an experiment.

Substation clustering based on improved KFCM algorithm with adaptive optimal clustering number selection

The premise and basis of load modeling are substation load composition inquiries and cluster analyses.However,the traditional kernel fuzzy C-means(KFCM)algorithm is limited by artificial clustering number selection and its convergence to local optimal solutions.To overcome these limitations,an improved KFCM algorithm with adaptive optimal clustering number selection is proposed in this paper.This algorithm optimizes the KFCM algorithm by combining the powerful global search ability of genetic algorithm and the robust local search ability of simulated annealing algorithm.The improved KFCM algorithm adaptively determines the ideal number of clusters using the clustering evaluation index ratio.Compared with the traditional KFCM algorithm,the enhanced KFCM algorithm has robust clustering and comprehensive abilities,enabling the efficient convergence to the global optimal solution.

A Novel Model of IDS Based on Fuzzy Cluster and Immune Principle

This paper presents a novel intrusion detection model based on fuzzy cluster and immune principle. The original rival penalized competitive learning (RPCL) algorithm is modified in order to address the problem of different variability of variables and correlation between variables, the sensitivity to initial number of clusters is also solved. Especially, we use the extended RPCL algorithm to determine the initial number of clusters in the fuzzy cluster algorithm. The genetic algorithm is used to optimize the radius deviation for the determination of characteristic function of abnormal subspace.

Supervised Fuzzy Mixture of Local Feature Models

This paper addresses an important issue in model combination, that is, model locality. Since usually a global linear model is unable to reflect nonlinearity and to characterize local features, especially in a complex sys-tem, we propose a mixture of local feature models to overcome these weaknesses. The basic idea is to split the entire input space into operating domains, and a recently developed feature-based model combination method is applied to build local models for each region. To realize this idea, three steps are required, which include clustering, local modeling and model combination, governed by a single objective function. An adaptive fuzzy parametric clustering algorithm is proposed to divide the whole input space into operating regimes, local feature models are created in each individual region by applying a recently developed fea-ture-based model combination method, and finally they are combined into a single mixture model. Corre-spondingly, a three-stage procedure is designed to optimize the complete objective function, which is actu-ally a hybrid Genetic Algorithm (GA). Our simulation results show that the adaptive fuzzy mixture of local feature models turns out to be superior to global models.

基于模糊聚类与改进遗传算法的异常电力工程数据识别技术

针对传统人工核查电力工程异常数据存在耗时费力及准确度较低的问题,文中提出了一种基于模糊聚类与改进遗传算法的数据识别技术。该技术采用模糊聚类算法对数据进行自动归类,并对异常数据加以识别。同时还设计了一种改进遗传算法增强了数据的全局搜索能力,进而提升整体算法的识别效率。基于Matlab进行的仿真验证结果表明,所提技术方案可有效地自动识别出电力工程中的异常数据。而在结合改进遗传算法后,该算法的识别准确率得到了显著提升,且识别时间也缩短了60%以上,实现了数据搜索能力与效率的平衡。

基于GA-WNN模型的光伏中期功率预测研究

为解决光伏发电存在限电情况下,光伏中期功率预测结果偏小导致预测精度降低的问题,提出了一种基于光伏可用功率的遗传算法(GA)优化小波神经网络(WNN)的预测模型。GA-WNN模型在预测日的相近日期内覆盖晴天、雨天、多云等多种天气类型,通过模糊C-均值聚类算法辨识限电情况,并将光伏可用功率作为训练目标,建立了WNN光伏中期预测训练模型。GA-WNN模型以预测日获取的光伏数值天气预报作为输入,经过训练后可以直接预测未来1~10 d的光伏中期功率。通过新疆某光伏运行电站的实际运行数据进行验证,预测精度达96%以上。将GA应用于WNN预测模型中,可显著提高光伏中期功率预测精度。

改进的模糊C-均值聚类方法

该文针对模糊C-均值算法容易收敛于局部极小点的缺陷,将遗传算法应用于模糊C-均值算法(FCM)的优化计算中,其中对传统遗传算法的编码方案、遗传算子约束条件及适应值函数等方面进行改进,提出了一种基于改进遗传算法的模糊聚类方法。实验表明,将改进的遗传算法与FCM算法结合起来进行聚类分析,可以在一定程度上避免FCM算法对初始值敏感和容易陷入局部最优解的缺陷,使聚类更合理,比单一使用FCM算法进行聚类分析的效果要好。

一种基于遗传算法的模糊聚类算法及其与FCM算法的结合

在各种糊聚类算法中 ,模糊C -均值聚类算法FCM (FuzzyC MeanClusteringAlgorithm )的应用最为广泛。但在实际的应用中 ,FCM算法却容易陷入局部最优解。因此 ,本文首先提出了一种基于遗传算法GA(GeneticAlgorithm )的模糊聚类分析方法 ,它利用了遗传算法随机搜索的特点 ,可以避免陷入局部最优解。实验表明 ,将该遗传算法与FCM算法结合起来进行聚类分析 ,比单一使用遗传算法或单一使用FCM算法进行聚类分析的效果都要好。

基于改进小生境遗传算法的电力系统无功优化

针对电力系统无功优化问题,提出一种改进小生境遗传算法来克服小生境遗传算法中小生境难以确定的不足,改善遗传算法容易陷入局部收敛和早熟的缺点。通过模糊动态聚类分析方法实现小生境群体的划分,然后利用适应度共享技术对小生境内个体适应度进行调整,以提高全局寻优能力。提出和运用隔代小生境共享机制、最优个体邻域搜索及保留策略等以提高算法的计算速度和收敛速度。通过对IEEE 57节点测试系统进行无功优化计算及结果分析,说明所提出算法的全局搜索能力强、效率高,能得到较好的结果。

基于遗传算法的模糊聚类分析

模糊C-均值聚类(FCM)应用广泛,但是它容易陷入局部最优,且对初始值很敏感。该文提出了一种基于遗传算法的模糊聚类方法,首先用遗传算法对模糊聚类中聚类中心的个数和聚类中心的选取进行指导,然后利用FCM进行聚类。实验结果表明:该方法可以在一定程度上避免FCM算法对初始值敏感和容易陷入局部最优解的缺陷,使聚类更合理,效果很好。

基于遗传算法的电网过电压分层模糊聚类识别

过电压识别对过电压起因及故障分析,改进输电线路和变电站设备绝缘配合具有重要意义。提出了基于小波多分辨率能量分布的电力系统过电压特征参量提取方法,针对特征向量存在交叉重叠的情况,引入分层模糊聚类识别的方法。构建分层识别的过电压分类树,通过对各种特征向量进行归纳分析与综合。特征向量集按不同的模块层次选取,形成模块层次结构,构成该层最佳特征量。将遗传算法的全局搜索和并行特性引入到模糊聚类中,弥补了模糊C-均值聚类(fuzzyC-means,FCM)算法存在局部性搜索和对初始聚类中心敏感等不足,通过全局搜索与局部搜索相结合的方式提高收敛速度,并加入移民策略来维持群体多样性,将该方法应用于实际过电压数据模式识别分类中,结果表明该方法能有效降低误分类率,从而对电力系统过电压类型进行有效识别。

一种新的动态聚类算法及其在热工过程模糊建模中的应用

文中提出的新型动态进化聚类算法克服了传统模糊聚类建模算法须事先确定规则数的缺陷。它通过改进的遗传策略来优化染色体长度,以实现对聚类个数进行全局寻优;同时,利用FCM算法加快了聚类中心参数的收敛;此外,通过引入免疫系统的记忆功能和疫苗接种机理,新算法得以快速稳定地收敛到最优解。利用这种高效的动态聚类算法辨识模糊模型,可以同时得到合适的模糊规则数和准确的前提参数。仿真实例验证了文中动态模糊聚类建模算法的有效性,将其应用于热工过程可获得高精度的非线性模糊模型。

基于免疫优势的克隆选择聚类算法

基于克隆选择原理和免疫优势理论,本文提出一种新的基于免疫优势的克隆选择聚类算法(Immun-odomaince based Clonal Selection Clustering Algorithm,IDCSCA),该算法通过在经典的克隆选择算法框架中,引入基于免疫优势理论的免疫优势算子实现了在线自适应动态获得先验知识和个体间的信息共享.新算法首先通过对群体中若干最优抗体的分析,提取免疫优势,然后将其推广到整个抗体群,通过在进化过程中利用积累的先验知识,在保证抗体种群多样性的基础上加快收敛速度.采用个5个数据集对算法性能进行了测试,与模糊C均值算法(Fuzzy C-means,FCM)、基于遗传算法的模糊聚类算法(Genetic Algorithm based Fuzzy C-means,GAFCM)以及基于克隆选择的模糊聚类算法(Clonal Selection Algorithm based Fuzzy C-means,CSAFCM)比较,结果表明IDCSCA能有效避免聚类中心迭代过程中陷入局部最优点的问题,而且聚类性能更稳定.

基于模糊聚类和遗传算法的具备解释性和精确性的模糊分类系统设计

提出一种基于模糊聚类和遗传算法的模糊分类系统的设计方法.首先定义了模糊分类系统的精确性指标,给出解释性的必要条件.然后利用聚类有效性分析确定模糊规则数目,利用模糊聚类算法辨识初始的模糊分类系统.随后利用模糊集合相似性分析与融合对初始的模糊分类系统进行约简,提高其解释性;利用遗传算法对约简后的模糊分类系统进行优化,提高其精确性,该过程反复迭代直至满足中止条件.最后利用该方法进行Iris数据样本分类,仿真结果验证了该方法的有效性.