A multi-objective particle swarm optimisation for filter-based feature selection in classification problems

Feature selection has the two main objectives of minimising the classification error rate and the number of features. Based on binary particle swarm optimisation (BPSO), we develop two novel multi-objective feature selection frameworks for classification, which are multi-objective binary PSO using the idea of non-dominated sorting (NSBPSO) and multi-objective binary PSO using the ideas of crowding, mutation and dominance (CMDBPSO). Four multi-objective feature selection methods are then developed by applying mutual information and entropy as two different filter evaluation criteria in each of the proposed frameworks. The proposed algorithms are examined and compared with a single objective method on eight benchmark data sets. Experimental results show that the proposed multi-objective algorithms can evolve a set of solutions that use a smaller number of features and achieve better classification performance than using all features. In most cases, NSBPSO achieves better results than the single objective algorithm and CMDBPSO outperforms all other methods mentioned above. This work represents the first study on multi-objective BPSO for filter-based feature selection.     

面向海量机械故障数据的胶囊网络算法研究

针对卷积神经网络算法在大规模故障数据集检测中出现的故障敏感度低、部分特征丢失等问题,提出一种基于优化胶囊网络算法的机械故障检测方案。胶囊网络算法采用多神经元封装的胶囊体结构设计,且包含多个胶囊层,具有更强的故障数据处理能力和泛化能力;经过squash函数挤压后的胶囊矢量可以更准确地提取和描述故障特征;升维胶囊矢量,基于特征编码和归一化的处理方式,可得到更准确的故障分类结果。实验结果显示:优化胶囊网络算法具有更强的故障特征聚类性能和迭代运算性能,故障集检测精度值高于经典卷积神经网络算法。     

Investigation on particle swarm optimisation for feature selection on high-dimensional data: local search and selection bias

Feature selection is an essential step in classification tasks with a large number of features, such as in gene expression data. Recent research has shown that particle swarm optimisation (PSO) is a promising approach to feature selection. However, it also has potential limitation to get stuck into local optima, especially for gene selection problems with a huge search space. Therefore, we developed a PSO algorithm (PSO-LSRG) with a fast “local search” combined with a gbest resetting mechanism as a way to improve the performance of PSO for feature selection. Furthermore, since many existing PSO-based feature selection approaches on the gene expression data have feature selection bias, i.e. no unseen test data is used, 2 sets of experiments on 10 gene expression datasets were designed: with and without feature selection bias. As compared to standard PSO, PSO with gbest resetting only, and PSO with local search only, PSO-LSRG obtained a substantial dimensionality reduction and a significant improvement on the classification performance in both sets of experiments. PSO-LSRG outperforms the other three algorithms when feature selection bias exists. When there is no feature selection bias, PSO-LSRG selects the smallest number of features in all cases, but the classification performance is slightly worse in a few cases, which may be caused by the overfitting problem. This shows that feature selection bias should be avoided when designing a feature selection algorithm to ensure its generalisation ability on unseen data.     

基于WTD-AR谱和MEA-BPNN的轴承故障诊断方法

针对滚动轴承故障诊断模型在噪声干扰下鲁棒性能差的问题,提出一种基于小波阈值去噪（WTD）、AR谱和思维进化算法（MEA）优化反向传播神经网络（BPNN）的轴承故障诊断方法。以原始振动信号为输入,采用小波方法分解重构原始信号滤除高频噪声,然后采用Burg算法估计AR模型参数提取降噪信号功率谱特征,最后将特征向量与对应标签分别作为MEA-BPNN神经网络的输入、输出进行训练,最终实现诊断。将该方法与一些先进的人工神经网络诊断方法作比较,测试该诊断模型的性能。研究结果表明：WTD-AR谱-MEA-BPNN诊断模型能够有效降低轴承振动信号的噪声干扰,实现特征增强,分辨率更高;相较于传统神经网络训练速度更快,在更短时间内甄别故障类型且识别率高。     

A novel artificial immune clonal selection classification and rule mining with swarm learning model

Metaheuristic optimisation algorithms have become popular choice for solving complex problems. By integrating Artificial Immune clonal selection algorithm (CSA) and particle swarm optimisation (PSO) algorithm, a novel hybrid Clonal Selection Classification and Rule Mining with Swarm Learning Algorithm (CS²) is proposed. The main goal of the approach is to exploit and explore the parallel computation merit of Clonal Selection and the speed and self-organisation merits of Particle Swarm by sharing information between clonal selection population and particle swarm. Hence, we employed the advantages of PSO to improve the mutation mechanism of the artificial immune CSA and to mine classification rules within datasets. Consequently, our proposed algorithm required less training time and memory cells in comparison to other AIS algorithms. In this paper, classification rule mining has been modelled as a miltiobjective optimisation problem with predictive accuracy. The multiobjective approach is intended to allow the PSO algorithm to return an approximation to the accuracy and comprehensibility border, containing solutions that are spread across the border. We compared our proposed algorithm classification accuracy CS² with five commonly used CSAs, namely: AIRS1, AIRS2, AIRS-Parallel, CLONALG, and CSCA using eight benchmark datasets. We also compared our proposed algorithm classification accuracy CS² with other five methods, namely: Naïve Bayes, SVM, MLP, CART, and RFB. The results show that the proposed algorithm is comparable to the 10 studied algorithms. As a result, the hybridisation, built of CSA and PSO, can develop respective merit, compensate opponent defect, and make search-optimal effect and speed better.     

基于特征融合与HPO-RVM的滚动轴承剩余寿命预测

为准确预测轴承的剩余使用寿命,提出基于特征融合与猎食者-猎物优化(HPO)算法优化相关向量机的轴承剩余寿命预测方法。提取时域、频域和时频域特征准确描述轴承的退化状态,利用综合评价指标对提取的特征进行筛选得到敏感特征集;采用核熵成分分析对敏感特征进行自适应融合,得到轴承的退化特征;构建混合核函数作为相关向量机的核函数以提高模型预测性能;最后,利用HPO算法得到混合核函数的参数,将寻优得到的参数用于寿命预测模型的训练。通过对轴承加速退化数据集进行实验,结果表明：所构建的寿命预测模型优于BP、ELM、SVM等模型,构造的混合核函数模型优于高斯核函数模型,采用的优化算法优于粒子群、遗传算法等。     

An evolutionary performance-enhanced PSO approach by using a BP neural-learning-based PID controller

In this paper, a novel evolutionary strategy-based particle swarm optimisation (PSO) approach is presented. The evolutionary strategy is dependent on a BP neural proportional integral derivative (PID) controller, which is intentionally placed between the position and the global best position in a closed loop of their relationship. The BP neural PID controller is designed to aid the position to well track the global best position. Furthermore, it can be utilised to improve the evolutionary dynamics of the PSO algorithm. The experiments for performance evaluation are tried on both analytical benchmark functions and an automatic control system of pulp consistency in pulping and paper-making engineering. The experimental results illustrate that the proposed approach enhances the diversity of swarms, considerably improves the global convergence efficiency and outperforms the PSO algorithm. In addition, it is also easily used in real industrial practice and offers a novel and convenient solution to engineering optimisation design of industrial systems.     

Direct back propagation neural dynamic programming-based particle swarm optimisation

In this paper, we introduce direct back propagation (BP) neural dynamic programming (NDP) into particle swarm optimisation (PSO). Thus, a direct BP NDP inspired PSO algorithm, which we call NDPSO, is proposed. In NDPSO, since direct BP NDP belongs to the class of heuristic dynamic programming algorithms based on model-based adaptive critic designs and often serves as an online learning control paradigm, critic BP neural network is trained to optimise a total reward-to-go objective, namely to balance Bellman's equation, while action BP neural network is used to train the inertia weight, cognitive, and social coefficients so that the critic BP network output can approach an ultimate reward-to-go objective of success. With the collective aid of action-critic BP neural networks, inertia weight, cognitive, and social coefficients become more adaptive. Besides, the NDPSO's mutation mechanism also has greatly improved the dynamic performance of the standard PSO. Empirical experiments are conducted on both unimodal and multimodal benchmark functions. The experimental results demonstrate NDPSO's effectiveness and superiority to many other PSO variants on solving most multimodal problems.     

一种基于物体特征提取的棒材快速计数方法

棒材计数的自动化水平是衡量企业智能化、信息化程度的一个重要方面。根据堆叠棒材图像中棒材像素的分布特征,提出一种基于物体特征提取的棒材快速计算方法,用以解决生产、生活中堆叠棒材快速计数问题。利用连通域标记算法对棒材二值图像中的物体像素进行标记处理并统计物体特征值,根据物体特征值进行堆叠棒材的自动计算。整个处理过程仅需要扫描图像一遍。实验结果表明:所提方法能够快速、准确实现堆叠棒材的自动计数。     

基于粒子群优化盲源分离方法的电机滚动轴承复合故障诊断

基于粒子群算法实现容易、精度高、收敛快等优点,将粒子群算法与盲源分离相结合,提出基于粒子群优化的盲源分离方法 (PSO-BSS),并将其应用于电机滚动轴承复合故障诊断中。PSO-BSS方法以峭度的绝对值之和作为目标函数,通过PSO寻找到目标函数的最大值,进而确定最优的分离矩阵。仿真结果表明:PSO-BSS方法能够实现多源复合故障信号的特征分离,并且在分离性能、算法收敛性以及运算速度方面都明显地优于传统的基于遗传算法的机械故障盲源分离方法。最后成功地将PSO-BSS方法应用于实际的滚动轴承内、外圈复合故障盲源分离中,取得良好的分析效果,验证了该方法的工程实用性。     

基于PSO/GA的立体视觉测量系统优化布局

探讨一种基于PSO/GA（粒子群优化/遗传算法）混合算法的立体视觉测量系统优化布局方法。以空间点目标的三维重构不确定度最小为目标,构建了立体视觉测量系统优化布局的目标函数。通过实例阐述了使用PSO/GA混合算法求解系统最优布局参数的过程,并且在MATLAB环境下对该方法做了验证。仿真实验结果表明：与传统的粒子群优化算法和遗传算法相比,使用PSO/GA混合算法得到的最佳个体适应度曲线上升速度最快,而且求得的系统最优布局参数使空间点目标的三维重构不确定度最小。     

A weighted pattern matching approach for classification of imbalanced data with a fireworks-based algorithm for feature selection

ABSTRACT

Learning a classifier from imbalanced data is a challenging problem in Machine learning. A dataset is said to be imbalanced when the number of instances belonging to one class is much less than the number of instances belonging to the other class. Classifiers that proves efficient on standard data fail when the data is imbalanced as they are over trained by the majority class instances. Since class imbalance is a common characteristic of real-world data, the need for better classifiers becomes essential. This paper proposes a novel instance-based classification algorithm called Weighted Pattern Matching based Classification (PMC+) for classifying imbalanced data. PMC+ classifies unlabelled instances by computing the absolute difference between the feature values of the instances in the dataset and the unlabelled instance. PMC+ employs a simple classification procedure with weights and shows reasonably good performance. To improve the performance of PMC+, Fireworks based Feature and Weight Selection algorithm based on the idea of PMC+ has been proposed. PMC+ is evaluated on 44 binary imbalanced datasets and 15 multiclass imbalanced datasets. Although PMC+ does not employ a resampling or cost-sensitive method, experiments show that PMC+ is effective for classification of imbalanced data. The results of the experiments were validated using various non-parametric statistical tests.     

基于优化RBF神经网络挤出机温度压力系统辨识

为了精确在线辨识橡胶复合挤出机控制过程中主要干扰变量与内部耦合关系,更好地实现对挤出机温度压力耦合系统的精准控制,采用RBF神经网络进行系统辨识研究,同时结合PSO算法引入GA算法中编码、杂交、交叉、变异等概念,设计了混合型PSO算法进一步优化RBF神经网络,完成对温度压力耦合系统的精准在线辨识。借助MATLAB软件进行神经网络训练,辨识系统耦合关系,同时与混合型PSO算法优化神经网络权值所辨识的效果进行对比。试验结果表明:采用混合型PSO算法优化RBF神经网络训练效果更佳,可以实现RBF神经网络高精度系统辨识;混合型PSO算法优化RBF神经网络应用于挤出机温度压力控制系统辨识,可以在一定程度上提升系统的辨识精度以及挤出机械的智能化水平。     

改进PSO-BP网络在故障诊断中的应用

针对油田抽油机井故障诊断方法较落后的问题,提出一种基于改进PSO-BP网络的故障诊断系统.神经网络权值的训练采用改进的PSO算法,克服了BP学习算法收敛速度慢、易陷入局部极值的缺点.将该网络用于抽油机井的故障诊断,并与传统BP模型的故障诊断结果进行比较.结果表明:基于改进PSO-BP的故障诊断方法正确率达96%以上,可以在更短的时间内、用更少的迭代次数达到精度要求,为设备检修提供了可靠的依据.     

基于贝叶斯图像模式识别技术的点焊质量评估

提出一种将点焊过程动态电极位移信号转化为二值图像的方法.基于图像特征分析,从焊点样本电极位移二值图像中提取出15个隐含特征.针对一系列对应不同焊接质量焊点样本电极位移二值图像特征,利用主成分分析消除图像特征间的互相关性,建立了基于最小风险贝叶斯图像识别技术的焊点质量分类器.分类器有效性测试结果表明,电极位移信号二值图像尽可能多的保留了焊点质量信息,特征提取算法简单、高效、易于实现;同时在小数据样本情况下,贝叶斯图像识别技术能够快速、准确地评判焊点质量,有较好的应用前景.     

基于深度学习的大规模图像高效识别算法研究

面对规模较大的图像识别任务时,基于卷积神经网络的深度学习方法存在训练时间过长的问题,导致识别效率不高。因此,提出一种基于局部特征深度信念网络的大规模图像高效识别算法。首先,该方法从原始图像中提取多个局部特征,并根据分配给图像的标签将每个局部特征分类。然后利用分类后的图像局部特征训练深度信念网络,获得网络的相关参数。最后利用深度信念网络进行图像识别。在CAS PEAL R1 大规模图像数据集上进行了图像识别实验,结果显示:提出的算法优于其他深度学习方法,具有较好的准确性和高效性。     

基于CAPSO-RBF的磁悬浮系统控制研究

为解决传统控制器磁悬浮球系统快速性和稳定性易受干扰等问题,建立云自适应粒子群优化(CAPSO)的RBF神经网络监督控制器。通过RBF神经网络学习整定PD控制器的输出后采用云自适应粒子群算法对RBF网络的3个参数进行归一动态优化。采用原有RBF神经网络梯度下降法、粒子群算法、云自适应粒子群算法分别训练后进行对比控制仿真。结果表明：基于CAPSO-RBF的混合控制算法实现了磁悬浮球系统自适应控制,其动态性能和稳态性方面有较好的提升。     

Solution of the one-dimensional Bratu equation arising in the fuel ignition model using ANN optimised with PSO and SQP

In this paper, an efficient procedure based on the neural networks methodology is presented for the solution of the fuel ignition model in one dimension. The neural networks were optimised with the particle swarm optimisation algorithm hybridised with sequential quadratic programming. The accuracy and convergence of the scheme are analysed by Monte Carlo simulations and their statistical analyses for three test cases of the problem represented by Bratu-type equations. It was found that the hybrid approach converges in all cases, and can solve the problem with higher accuracy and reliability than most of the methodologies used so far to solve this problem.     

基于混合算法的典型调度问题求解研究

文章介绍了粒子群优化的搜索策略与基本算法,然后通过相关的位置和速度定义,构造一种特殊的粒子群优化算法,并将该算法与遗传算法结合,提出用于求解典型调度问题的混合算法.实验表明了该混合算法在求解调度问题的可行性及其优越性.     

基于PSO和属性约减的模糊神经网络机床故障诊断

数控机床伺服系统工作原理复杂。为了提高智能故障诊断的准确性,提出基于PSO理论和属性约束规则(RSM)的模糊神经网络算法。先对训练样本进行属性约减;由于PSO算法具有全局优化能力和BP算法具有局部搜索效率高的优点,利用它们训练神经网络,克服了传统方法收敛速度慢的缺点;并通过Matlab仿真证明,该方法具有较高的诊断准确性。