Research of Improved Fuzzy c-means Algorithm Based on a New Metric Norm

For the question that fuzzy c-means(FCM)clustering algorithm has the disadvantages of being too sensitive to the initial cluster centers and easily trapped in local optima,this paper introduces a new metric norm in FCM and particle swarm optimization(PSO)clustering algorithm,and proposes a parallel optimization algorithm using an improved fuzzy c-means method combined with particle swarm optimization(AF-APSO).The experiment shows that the AF-APSO can avoid local optima,and get the best fitness and clustering performance significantly.

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 Fixed Suppressed Rate Selection Method for Suppressed Fuzzy C-Means Clustering Algorithm

Suppressed fuzzy c-means (S-FCM) clustering algorithm with the intention of combining the higher speed of hard c-means clustering algorithm and the better classification performance of fuzzy c-means clustering algorithm had been studied by many researchers and applied in many fields. In the algorithm, how to select the suppressed rate is a key step. In this paper, we give a method to select the fixed suppressed rate by the structure of the data itself. The experimental results show that the proposed method is a suitable way to select the suppressed rate in suppressed fuzzy c-means clustering algorithm.

Hybrid Clustering Using Firefly Optimization and Fuzzy C-Means Algorithm

Classifying the data into a meaningful group is one of the fundamental ways of understanding and learning the valuable information. High-quality clustering methods are necessary for the valuable and efficient analysis of the increasing data. The Firefly Algorithm (FA) is one of the bio-inspired algorithms and it is recently used to solve the clustering problems. In this paper, Hybrid F-Firefly algorithm is developed by combining the Fuzzy C-Means (FCM) with FA to improve the clustering accuracy with global optimum solution. The Hybrid F-Firefly algorithm is developed by incorporating FCM operator at the end of each iteration in FA algorithm. This proposed algorithm is designed to utilize the goodness of existing algorithm and to enhance the original FA algorithm by solving the shortcomings in the FCM algorithm like the trapping in local optima and sensitive to initial seed points. In this research work, the Hybrid F-Firefly algorithm is implemented and experimentally tested for various performance measures under six different benchmark datasets. From the experimental results, it is observed that the Hybrid F-Firefly algorithm significantly improves the intra-cluster distance when compared with the existing algorithms like K-means, FCM and FA algorithm.

Improved Supervised and Unsupervised Metaheuristic-Based Approaches to Detect Intrusion in Various Datasets

Due to the increasing number of cyber-attacks,the necessity to develop efficient intrusion detection systems(IDS)is more imperative than ever.In IDS research,the most effectively used methodology is based on supervised Neural Networks(NN)and unsupervised clustering,but there are few works dedicated to their hybridization with metaheuristic algorithms.As intrusion detection data usually contains several features,it is essential to select the best ones appropriately.Linear Discriminant Analysis(LDA)and t-statistic are considered as efficient conventional techniques to select the best features,but they have been little exploited in IDS design.Thus,the research proposed in this paper can be summarized as follows.a)The proposed approach aims to use hybridized unsupervised and hybridized supervised detection processes of all the attack categories in the CICIDS2017 Dataset.Nevertheless,owing to the large size of the CICIDS2017 Dataset,only 25%of the data was used.b)As a feature selection method,the LDAperformancemeasure is chosen and combinedwith the t-statistic.c)For intrusion detection,unsupervised Fuzzy C-means(FCM)clustering and supervised Back-propagation NN are adopted.d)In addition and in order to enhance the suggested classifiers,FCM and NN are hybridized with the seven most known metaheuristic algorithms,including Genetic Algorithm(GA),Particle Swarm Optimization(PSO),Differential Evolution(DE),Cultural Algorithm(CA),Harmony Search(HS),Ant-Lion Optimizer(ALO)and Black Hole(BH)Algorithm.Performance metrics extracted from confusion matrices,such as accuracy,precision,sensitivity and F1-score are exploited.The experimental result for the proposed intrusion detection,based on training and test CICIDS2017 datasets,indicated that PSO,GA and ALO-based NNs can achieve promising results.PSO-NN produces a tested accuracy,global sensitivity and F1-score of 99.97%,99.95%and 99.96%,respectively,outperforming performance concluded in several related works.Furthermore,the best-proposed approaches are valued in the most recent intrusion detection datasets:CSE-CICIDS2018 and LUFlow2020.The evaluation fallouts consolidate the previous results and confirm their correctness.

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.

MATHEMATICAL ANALYSIS OF MUTATION OPERATOR AND ITS IMPROVED STRATEGY IN GENETIC ALGORITHMS

This paper analyzes the optimization problem of mutation probability in genetic algorithms by applying the definition of i-bit improved sub-space. Then fuzzy reasoning technique is adopted to determine the optimal mutation probability in different conditions. The superior convergence property of the new method is evaluated by applying it to two simulation examples.

Agent Based Segmentation of the MRI Brain Using a Robust C-Means Algorithm

In the last decade, the MRI (Magnetic Resonance Imaging) image segmentation has become one of the most active research fields in the medical imaging domain. Because of the fuzzy nature of the MRI images, many researchers have adopted the fuzzy clustering approach to segment them. In this work, a fast and robust multi-agent system (MAS) for MRI segmentation of the brain is proposed. This system gets its robustness from a robust c-means algorithm (RFCM) and obtains its fastness from the beneficial properties of agents, such as autonomy, social ability and reactivity. To show the efficiency of the proposed method, we test it on a normal brain brought from the BrainWeb Simulated Brain Database. The experimental results are valuable in both robustness to noise and running times standpoints.

The Application of Improved Fuzzy Comprehensive Evaluation method in Practice Teaching Quality Evaluation System

According to the theory of fuzzy mathematics, Fuzzy comprehensive evaluation method of the original algorithm is improved, and reduced the possibility loss of the original evaluation data. The improved algorithm is applied in the practice teaching quality evaluation system, and improved the practice teaching quality evaluation results and the accuracy of visual, and promote the teaching management scientific, standardized and institutionalized. In order to establish incentive mechanism, it can bring a positive role to improve teaching quality.

Abnormal State Detection of OLTC Based on Improved Fuzzy C-means Clustering

An accurate extraction of vibration signal characteristics of an on-load tap changer(OLTC)during contact switching can effectively help detect its abnormal state.Therefore,an improved fuzzy C-means clustering method for abnormal state detection of the OLTC contact is proposed.First,the wavelet packet and singular spectrum analysis are used to denoise the vibration signal generated by the moving and static contacts of the OLTC.Then,the Hilbert-Huang transform that is optimized by the ensemble empirical mode decomposition(EEMD)is used to decompose the vibration signal and extract the boundary spectrum features.Finally,the gray wolf algorithm-based fuzzy C-means clustering is used to denoise the signal and determine the abnormal states of the OLTC contact.An analysis of the experimental data shows that the proposed secondary denoising method has a better denoising effect compared to the single denoising method.The EEMD can improve the modal aliasing effect,and the improved fuzzy C-means clustering can effectively identify the abnormal state of the OLTC contacts.The analysis results of field measured data further verify the effectiveness of the proposed method and provide a reference for the abnormal state detection of the OLTC.

A NEW UNSUPERVISED CLASSIFICATION ALGORITHM FOR POLARIMETRIC SAR IMAGES BASED ON FUZZY SET THEORY

In this letter, a new method is proposed for unsupervised classification of terrain types and man-made objects using POLarimetric Synthetic Aperture Radar (POLSAR) data. This technique is a combi-nation of the usage of polarimetric information of SAR images and the unsupervised classification method based on fuzzy set theory. Image quantization and image enhancement are used to preprocess the POLSAR data. Then the polarimetric information and Fuzzy C-Means (FCM) clustering algorithm are used to classify the preprocessed images. The advantages of this algorithm are the automated classification, its high classifica-tion accuracy, fast convergence and high stability. The effectiveness of this algorithm is demonstrated by ex-periments using SIR-C/X-SAR (Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar) data.

Alternative Fuzzy Cluster Segmentation of Remote Sensing Images Based on Adaptive Genetic Algorithm

Remote sensing image segmentation is the basis of image understanding and analysis. However,the precision and the speed of segmentation can not meet the need of image analysis,due to strong uncertainty and rich texture details of remote sensing images. We proposed a new segmentation method based on Adaptive Genetic Algorithm(AGA) and Alternative Fuzzy C-Means(AFCM) . Segmentation thresholds were identified by AGA. Then the image was segmented by AFCM. The results indicate that the precision and the speed of segmentation have been greatly increased,and the accuracy of threshold selection is much higher compared with traditional Otsu and Fuzzy C-Means(FCM) segmentation methods. The segmentation results also show that multi-thresholds segmentation has been achieved by combining AGA with AFCM.

Employment Quality EvaluationModel Based on Hybrid Intelligent Algorithm

In order to solve the defect of large error in current employment quality evaluation,an employment quality evaluation model based on grey correlation degree method and fuzzy C-means(FCM)is proposed.Firstly,it analyzes the related research work of employment quality evaluation,establishes the employment quality evaluation index system,collects the index data,and normalizes the index data;Then,the weight value of employment quality evaluation index is determined by Grey relational analysis method,and some unimportant indexes are removed;Finally,the employment quality evaluation model is established by using fuzzy cluster analysis algorithm,and compared with other employment quality evaluation models.The test results show that the employment quality evaluation accuracy of the design model exceeds 93%,the employment quality evaluation error can meet the requirements of practical application,and the employment quality evaluation effect is much better than the comparison model.The comparison test verifies the superiority of the model.

基于改进鲸鱼优化算法的AGV柔性作业车间多目标优化调度

针对柔性作业车间的自动引导车辆(Automated Guided Vehicle,AGV)调度问题,基于可持续视角,考虑车间能耗问题,在机器和AVG数量均存在数量约束的条件下,以最小化最大完工时间、车间能耗和AGV使用数量为优化目标构建可持续柔性车间调度模型。首先,设计一种改进鲸鱼优化算法(Improved Whale Optimization Algorithm,IWOA),在标准的鲸鱼优化算法的基础上引入非线性收敛因子和自适应惯性权重以提升算法的搜索能力和收敛速度;其次,使用模糊隶属度理论构建了损失函数,以获得多目标模型的最优折衷解;最后,基于算例实验验证算法性能。实验结果表明改进鲸鱼优化算法在求解2个算例时均表现出良好的效果,为求解采用AGV运输的可持续柔性作业车间多目标优化调度提供了一种有效的实践途径。

面向个性化需求的燃料电池测试台价值评估方法

针对不同个性化需求的燃料电池测试台(fuel cell test bench,FCTB)难以评价和量化评估的问题,提出一种基于改进和声搜索算法的FCTB价值评估方法.针对不同FCTB的个性化需求,建立了FCTB综合评估指标体系;结合用户的个性化需求,采用模糊层次分析法分配指标权重,构建价值定量评估模型,将权重求取问题转换为约束优化问题;提出一种改进和声搜索算法对问题进行求解,通过设计解向量生成机制和参数自适应调整策略,用于提高传统和声搜索算法的求解效率和搜索能力.仿真结果表明,本文方法在计算效率和精度方面具有优势,并能够根据不同的需求特性实现对FCTB方案做出定量的价值评估.

基于改进粒子群算法的机械手抓取力自整定模糊PID控制

为提高欠驱动机械手在易碎零件分拣过程中的稳定性,通过改进粒子群算法,给出一种优化其抓取性能的模糊PID控制算法。首先,分析欠驱动机械手抓取力控制系统的特性,提出粒子群算法与模糊PID抓取力控制系统相结合的具体策略。其次,将动态惯性权重等方法引入粒子群算法中,以提高其迭代速度并防止其陷入局部最优。在此基础上,利用改进后的粒子群算法优化模糊PID控制器的相关参数,实现了对模糊规则权重及量化因子的在线自整定,解决了PID参数无法动态调整的问题。最后,对其进行仿真分析。结果表明:该控制算法可以在0.8 s内达到稳定抓取力,稳态误差小于0.2%,扰动整定时间为0.262 s,系统的瞬态响应速度、控制精度以及稳定性均有明显提高。

突发自然灾害下的两阶段多目标应急物资中心选址问题研究

针对突发灾害情况下需求不确定的选址问题,构建最小化经济成本和最大化满意度的应急物资中心选址模型。首先,将选址问题划分为初期和后期的两阶段问题;其次,对物资需求量进行模糊需求预测,并使用可信性模糊机会约束规划将其转化为确定型约束;最后,设计改进灰狼优化(Improved Grey Wolf Optimization,IGWO)算法求解问题。IGWO算法采用佳点集初始化种群,对收敛因子进行余弦规律的非线性变化,并在粒子群优化(Particle Swarm Optimization,PSO)算法个体记忆的启发下,设计个体位置更新公式。在用10个标准函数验证IGWO有效性的基础上,通过湖北省新型冠状病毒应急物资中心选址案例分析,表明IGWO算法能有效求解多目标选址问题,在提高满意度的基础上降低经济成本,且多阶段模型在平衡满意度和经济成本方面结果更优。

基于改进机器学习的图书馆机器人自主避障控制研究

为控制图书馆机器人在行进过程中自动躲避障碍,达到理想工作效果,提出基于改进机器学习的图书馆机器人自主避障控制方法;采集图书馆机器人与目标障碍物距离信息,感知环境特征向量,当成卷积神经网络输入,经卷积、池化等操作,输出图书馆机器人对当前环境感知结果,该结果经输入输出变量模糊化、模糊推理以及输出变量解模糊等操作后,实现图书馆机器人自主避障无冲突运行;实验结果表明:该方法自主避障控制效果较好,避障行驶距离短,高速运行时反应更快,能够避开多个障碍物,识别分类结果与实际感知环境类型一致。

基于模糊控制与改进NMPC算法的机器人轨迹控制方法研究

机器人的运动轨迹具有强非线性和强耦合性的特点,在运动过程中包含多种不确定因素,故提出了基于模糊控制与改进NMPC算法的机器人轨迹控制方法。首先通过动力学理论建立运动轨迹方程,逐步分解轨迹位置姿态,根据轨迹误差设计虚拟变量并进行推导,矫正轨迹姿态误差;然后使用模糊控制确定变量隶属函数,规范轨迹运动范围;最后利用改进NMPC算法构建控制模型,实现机器人轨迹控制。实验证明,该方法可有效跟踪不同类型的轨迹,具有重要的应用价值。

基于改进模糊层次分析法的病险水库除险加固效果评价

为选择可行的加固方案,最大程度地改善病险水库的工作性能,综合考虑除险加固方案的效果可靠性、经济合理性、技术可行性和施工便利性等指标,构建水库除险加固方案多层次优选模型,采用经加速遗传算法改进的模糊层次分析法确定各优选子系统及各指标权重,提出水库加固效果多层次优选评价方法,并选择典型水库进行了验证。结果表明:对于优选子系统,技术可行性和效果可靠性子系统权重较大,分别为0.309和0.298;对于优选指标,综合权重较大的是施工单位水平的高低、稳定性要求满足程度、加固方案与引起大坝加固原因的适应性、加固方案与大坝所处地域适应性等指标。典型水库应用实例中塑性混凝土防渗墙方案综合评价值(0.797)相对较优。