Unsupervised Clustering Based an Adaptive Particle Swarm Optimization Algorithm

Clustering analysis is the major application area of data mining where particle swarm optimization (PSO) is being widely implemented due to its simplicity and efficiency. In this paper, we present a new variant of PSO algorithm well tailored to clustering analysis. The proposed algorithm encodes each particle as a bi-dimensional vector, where in the first dimension we look for the optimal number of clusters and in the second dimension, we look for the best centroid of each cluster. In this PSO clustering algorithm a new updating positions rule is proposed to deal with our clustering objective. The performance of the proposed algorithm is tested according to artificial datasets and real datasets. The achieved results present actually good performance and still promising in future perspective.     

Evolutionary fuzzy particle swarm optimization vector quantization learning scheme in image compression

This article develops an evolutional fuzzy particle swarm optimization (FPSO) learning algorithm to self extract the near optimum codebook of vector quantization (VQ) for carrying on image compression. The fuzzy particle swarm optimization vector quantization (FPSOVQ) learning schemes, combined advantages of the adaptive fuzzy inference method (FIM), the simple VQ concept and the efficient particle swarm optimization (PSO), are considered at the same time to automatically create near optimum codebook to achieve the application of image compression. The FIM is known as a soft decision to measure the relational grade for a given sequence. In our research, the FIM is applied to determine the similar grade between the codebook and the original image patterns. In spite of popular usage of Linde–Buzo–Grey (LBG) algorithm, the powerful evolutional PSO learning algorithm is taken to optimize the fuzzy inference system, which is used to extract appropriate codebooks for compressing several input testing grey-level images. The proposed FPSOVQ learning scheme compared with LBG based VQ learning method is presented to demonstrate its great result in several real image compression examples.     

Cooperative bare-bone particle swarm optimization for data clustering

Cooperative coevolution (CC) was used to improve the performance of evolutionary algorithms (EAs) on complex optimization problems in a divide-and-conquer way. In this paper, we show that the CC framework can be very helpful to improve the performance of particle swarm optimization (PSO) on clustering high-dimensional datasets. Based on CC framework, the original partitional clustering problem is first decomposed to several subproblems, each of which is then evolved by an optimizer independently. We employ a very simple but efficient optimization algorithm, namely bare-bone particle swarm optimization (BPSO), as the optimizer to solve each subproblem cooperatively. In addition, we design a new centroid-based encoding schema for each particle and apply the Chernoff bounds to decide a proper population size. The experimental results on synthetic and real-life datasets illustrate the effectiveness and efficiency of the BPSO and CC framework. The comparisons show the proposed algorithm significantly outperforms five EA-based clustering algorithms, i.e., PSO, SRPSO, ACO, ABC and DE, and K-means on most of the datasets.     

基于自适应均值粒子群算法的SVM参数优化方法

针对传统粒子群算法(Particle Swarm Optimization,PSO)对支持向量机(Support Vector Machine,SVM)参数寻优时的低效问题,运用了自适应均值粒子群算法(Adaptive Mean Particle Swarm Optimization,MAPSO)对SVM参数进行优化(MAPSO-SVM算法).采用自适应策略,引入了余弦函数、非线性动态调整惯性因子,每次进化都根据种群中粒子的适应度值大小将粒子分为3个等级,对每个等级的粒子赋予相应的惯性因子,将PSO算法速度更新方程中的个体历史最优位置和全局最优位置用它们的线性组合代替.分别用SVM、PSO-SVM和MAPSO-SVM算法对UCI中不同数据集进行实验测试,结果表明MAPSO-SVM算法比SVM和PSO-SVM算法的分类效果更好,分类准确率比SVM和PSO-SVM算法分别平均提高了14.7290％和1.8347％,同时与PSO-SVM算法相比,算法的收敛精度和效率更高.     

离散多目标量子微粒群聚类算法*

聚类是数据挖掘中重要的数据处理方法.文中提出改进的离散多目标量子微粒群聚类算法.针对类中心数目未知的情况,引入整数编码策略,基于Canopy策略预测类中心的数目,设计有效的微粒群初始化策略.通过引入与、并和差异算子,定义改进的离散量子微粒更新公式.将文中算法应用于7组真实数据集,并对比2种典型单目标聚类算法和3种多目标聚类算法,验证文中算法性能.     

A hybrid particle swarm optimization approach for clustering and classification of datasets

This paper introduces a new hybrid cluster validity method based on particle swarm optimization, for successfully solving one of the most popular clustering/classifying complex datasets problems. The proposed method for the solution of the clustering/classifying problem, designated as PSORS index method, combines a particle swarm optimization (PSO) algorithm, Rough Set (RS) theory and a modified form of the Huang index function. In contrast to the Huang index method which simply assigns a constant number of clusters to each attribute, this method could cluster the values of the individual attributes within the dataset and achieves both the optimal number of clusters and the optimal classification accuracy. The validity of the proposed approach is investigated by comparing the classification results obtained for a real-world dataset with those obtained by pseudo-supervised classification BPNN, decision-tree and Huang index methods. There is good evidence to show that the proposed PSORS index method not only has a superior clustering accomplishment than the considered methods, but also achieves better classification accuracy.     

Image vector quantization algorithm via honey bee mating optimization

The vector quantization (VQ) was a powerful technique in the applications of digital image compression. The traditionally widely used method such as the Linde–Buzo–Gray (LBG) algorithm always generated local optimal codebook. Recently, particle swarm optimization (PSO) is adapted to obtain the near-global optimal codebook of vector quantization. An alternative method, called the quantum particle swarm optimization (QPSO) had been developed to improve the results of original PSO algorithm. In this paper, we applied a new swarm algorithm, honey bee mating optimization, to construct the codebook of vector quantization. The results were compared with the other three methods that are LBG, PSO–LBG and QPSO–LBG algorithms. Experimental results showed that the proposed HBMO–LBG algorithm is more reliable and the reconstructed images get higher quality than those generated from the other three methods.     

基于群能量恒定的粒子群优化算法

针对标准粒子群优化(PSO)算法在寻优过程中容易出现早熟的情况,提出一种群能量恒定的粒子群优化(SEC-PSO)算法.算法根据粒子内能进行动态分群,对较优群体采取引入最差粒子的速度更新策略,对较差群体采取带有惩罚机制的速度更新策略,由其分担由于较优群体速度降低而产生的整群能量损失,从而有效地避免了PSO算法的早熟.典型优化问题的仿真结果表明,该算法具有较强的全局搜索能力和较快的收敛速度,优化性能得到显著的提高.     

基于改进粒子群优化的无标记数据鲁棒聚类算法

已有的聚类算法大多仅考虑单一的目标,导致对某些形状的数据集性能较弱,对此提出一种基于改进粒子群优化的无标记数据鲁棒聚类算法。优化阶段:首先,采用多目标粒子群优化的经典形式生成聚类解集合;然后,使用K-means算法生成随机分布的初始化种群,并为其分配随机初始化的速度;最终,采用MaxiMin策略确定帕累托最优解。决策阶段：测量帕累托解集与理想解的距离,将距离最短的帕累托解作为最终聚类解。对比实验结果表明,本算法对不同形状的数据集均可获得较优的类簇数量,对目标问题的复杂度具有较好的鲁棒性。     

基于相似历史信息迁移学习的进化优化框架

现有进化算法大都从问题的零初始信息开始搜索最优解, 没有利用先前解决相似问题时获得的历史信息, 在一定程度上浪费了计算资源.将迁移学习的思想扩展到进化优化领域, 本文研究一种基于相似历史信息迁移学习的进化优化框架.从已解决问题的模型库中找到与新问题匹配的历史问题, 将历史问题对应的知识迁移到新问题的求解过程中, 以提高种群的搜索效率.首先, 定义一种基于多分布估计的最大均值差异指标, 用来评价新问题与历史模型之间的匹配程度; 接着, 将相匹配的历史问题的知识迁移到新问题中, 给出一种基于模型匹配程度的进化种群初始化策略, 以加快算法的搜索速度; 然后, 给出一种基于迭代聚类的代表个体保存策略, 保留求解过程中产生的优势信息, 用于更新历史模型库; 最后, 将自适应骨干粒子群优化算法嵌入到所提框架, 给出一种基于相似历史信息迁移学习的骨干粒子群优化算法.针对多个改进的典型测试函数, 实验结果表明, 所提迁移策略可以加速粒子群的搜索过程, 显著提高算法的收敛速度和搜索效率.     

Modified binary PSO for feature selection using SVM applied to mortality prediction of septic patients

This paper proposes a modified binary particle swarm optimization (MBPSO) method for feature selection with the simultaneous optimization of SVM kernel parameter setting, applied to mortality prediction in septic patients. An enhanced version of binary particle swarm optimization, designed to cope with premature convergence of the BPSO algorithm is proposed. MBPSO control the swarm variability using the velocity and the similarity between best swarm solutions. This paper uses support vector machines in a wrapper approach, where the kernel parameters are optimized at the same time. The approach is applied to predict the outcome (survived or deceased) of patients with septic shock. Further, MBPSO is tested in several benchmark datasets and is compared with other PSO based algorithms and genetic algorithms (GA). The experimental results showed that the proposed approach can correctly select the discriminating input features and also achieve high classification accuracy, specially when compared to other PSO based algorithms. When compared to GA, MBPSO is similar in terms of accuracy, but the subset solutions have less selected features.     

基于改进PSO算法的机器人路径规划及实验

针对粒子群优化（PSO）算法存在的优化精度低以及早熟的缺点,提出一种改进的PSO算法用于机器人路径规划．根据梯度下降法中变量沿负梯度方向变化的原则,提出了改进的粒子速度更新模型．为了提高粒子的搜寻效率及精度,增加了自适应粒子位置更新系数．引入ε贪心策略设计了改进的粒子群优化算法．在部分优化测试函数上的多次试验结果表明,所提算法较其他算法模型搜索精度至少提高2倍,收敛速度也有大幅度的提升．将所提算法和改进的DC-HPSO（动态聚类混合粒子群优化）算法应用于静态障碍物下的路径规划仿真和实际试验,结果表明所提模型具有高精度、高效率、高成功率的优点．     

融合Shapley值和粒子群优化算法的混合特征选择算法

针对在模式分类问题中,数据往往存在不相关的或冗余的特征,从而影响分类的准确性的问题,提出一种融合Shapley值和粒子群优化算法的混合特征选择算法,以利用最少的特征获得最佳分类效果。在粒子群优化算法的局部搜索中引入博弈论的Shapley值,首先计算粒子（特征子集）中每个特征对分类效果的贡献值（Shapley值）,然后逐步删除Shapley值最低的特征以优化特征子集,进而更新粒子,同时也增强了算法的全局搜索能力,最后将改进后的粒子群优化算法运用于特征选择,以支持向量机分类器的分类性能和选择的特征数目作为特征子集评价标准,对UCI机器学习数据集和基因表达数据集的17个具有不同特征数量的医疗数据集进行分类实验。实验结果表明所提算法能有效地删除数据集中55%以上不相关的或冗余的特征,尤其对于中大型数据集能删减80%以上,并且所选择的特征子集也具有较好的分类能力,分类准确率能提高2至23个百分点。     

基于PSO的模糊K-Prototypes聚类

模糊K-Prototypes(FKP)算法能够对包含数值属性和分类属性相混合的数据集进行有效聚类,但是存在对初始值敏感、容易陷入局部极小值的问题.为了克服该缺点,提出了一种基于粒子群优化(PSO)算法和FKP算法的混合聚类算法,先利用PSO算法确定FKP的初始聚类中心,再将PSO聚类结果作为后续FKP算法的初始值.实验结果表明,新算法具有良好的收敛性和稳定性,聚类效果优于单一使用FKP算法.     

一种改进细菌觅食优化算法及其在软测量建模中的应用

针对软测量建模中模型参数的优化需求,在分析细菌觅食优化算法(BFOA)和粒子群优化(PSO)算法的基础上,将二者有机结合,提出了一种新型细菌觅食粒子群混合优化算法(BSOA)。该算法将PSO粒子移动的思想引入BFOA,有效解决了BFOA趋向性操作中细菌位置更新的盲目性。将其分别用于典型函数的寻优与成品油研究法辛烷值最小二乘支持向量机(LSSVM)模型参数的优化,仿真结果表明:该方法有效增强了算法的全局寻优能力与收敛速度,并在一定程度上改善了模型的预测精度与泛化能力。     

基于粒子群优化算法的支持向量机参数选择

由于支持向量机的主要参数的选择能够在很大程度上影响分类性能和效果,并且目前参数优化缺乏理论指导,提出一种粒子群优化算法以优化支持向量机参数的方法.该方法通过引入非线性递减惯性权值和异步线性变化的学习因子策略来改善标准粒子群算法的后期收敛速度慢、易陷入局部最优的缺陷.实验结果表明,相对于标准粒子群算法,本方法在参数优化方面具有良好的鲁棒性、快速收敛和全局搜索能力,具有更高的分类精确度和效率.     

改进的粒子群模糊聚类方法

针对基于粒子群的模糊聚类算法以隶属度编码时对噪音敏感,以及处理样本数小于样本维数的数据集效果较差等问题,通过改进其中的模糊聚类约束方法,提出一种改进的基于粒子群的模糊聚类方法.当样本对各类的隶属度之和不为1时,新方法在粒子群优化得出的隶属度基础上,根据样本与各类之间的距离对隶属度进一步分配,以使隶属度满足模糊聚类约束条件.新方法显著地改善了在隶属度编码下使用粒子群进行模糊聚类的效果,并通过典型的数据集进行了验证.     

一种新的基于粒子群和模拟退火的聚类算法

提出了一种新的基于粒子群和模拟退火的聚类算法。每个粒子作为聚类问题的一个可行解组成粒子群,粒子的位置由聚类中心向量表示。为避免粒子群陷入局部最优解,结合聚类问题的实际特点,提出了利用模拟退火的概率突跳性的两个解决方案。实验结果表明,新算法增强了全空间的搜索能力,性能优于粒子群算法和传统的K-means算法,具有较好的收敛性,是一种有效的聚类算法。     

Attributed multi-objective comprehensive learning particle swarm optimization for optimal security of networks

In particle swarm optimization (PSO) each particle uses its personal and global or local best positions by linear summation. However, it is very time consuming to find the global or local best positions in case of complex problems. To overcome this problem, we propose a new multi-objective variant of PSO called attributed multi-objective comprehensive learning particle swarm optimizer (A-MOCLPSO). In this technique, we do not use global or local best positions to modify the velocity of a particle; instead, we use the best position of a randomly selected particle from the whole population to update the velocity of each dimension. This method not only increases the speed of the algorithm but also searches in more promising areas of the search space. We perform an extensive experimentation on well-known benchmark problems such as Schaffer (SCH), Kursawa (KUR), and Zitzler–Deb–Thiele (ZDT) functions. The experiments show very convincing results when the proposed technique is compared with existing versions of PSO known as multi-objective comprehensive learning particle swarm optimizer (MOCLPSO) and multi-objective particle swarm optimization (MOPSO), as well as non-dominated sorting genetic algorithm II (NSGA-II). As a case study, we apply our proposed A-MOCLPSO algorithm on an attack tree model for the security hardening problem of a networked system in order to optimize the total security cost and the residual damage, and provide diverse solutions for the problem. The results of our experiments show that the proposed algorithm outperforms the previous solutions obtained for the security hardening problem using NSGA-II, as well as MOCLPSO for the same problem. Hence, the proposed algorithm can be considered as a strong alternative to solve multi-objective optimization problems.     

Extensions of vector quantization for incremental clustering

In this paper, we extend the conventional vector quantization by incorporating a vigilance parameter, which steers the tradeoff between plasticity and stability during incremental online learning. This is motivated in the adaptive resonance theory (ART) network approach and is exploited in our paper for forming a one-pass incremental and evolving variant of vector quantization. This variant can be applied for online clustering, classification and approximation tasks with an unknown number of clusters. Additionally, two novel extensions are described: one concerns the incorporation of the sphere of influence of clusters in the vector quantization learning process by selecting the ‘winning cluster’ based on the distances of a data point to the surface of all clusters. Another one introduces a deletion of cluster satellites and an online split-and-merge strategy: clusters are dynamically split and merged after each incremental learning step. Both strategies prevent the algorithm to generate a wrong cluster partition due to a bad a priori setting of the most essential parameter(s). The extensions will be applied to clustering of two- and high-dimensional data, within an image classification framework and for model-based fault detection based on data-driven evolving fuzzy models.