一种改进的小波变异粒子群优化算法

为提高粒子群优化(PSO)算法的优化性能,提出一种改进的小波变异粒子群算法(IPSOWM)。在每次迭代时以一定的概率选中粒子进行小波变异扰动,从而克服PSO算法后期易发生早熟收敛和陷入局部最优的缺点。数值仿真结果表明,IPSOWM算法的搜索精度、收敛速度及稳定性均优于PSO和PSOWM算法。     

新的全局-局部最优最小值粒子群优化算法

为了提高粒子群优化算法的收敛速度,克服陷入局部最优的缺点,在全局-局部最优粒子群优化算法的基础上,提出了一种新的改进粒子群优化算法——全局-局部最优最小值粒子群优化算法.该算法把惯性权重和学习因子分别通过结合全局和局部最优最小值来进行改写,速度更新公式也做了相应的简化.仿真实验表明该算法在收敛速度和寻优质量上都优于基于LDIW策略改进的粒子群算法和全局-局部最优粒子群算法.     

虚拟企业伙伴选择的遗传粒子群混合算法

针对标准粒子群优化算法易陷入局部最优的缺点,提出了一种遗传粒子群混合算法。通过对算法中惰性粒子和局部最优粒子分别进行交叉变异,以及消除粒子速度对寻优的干扰,从而避免了粒子种群单一化和局部最优的问题。将该算法应用于虚拟企业伙伴选择实验,结果表明在进化代数和最优值方面是令人满意的。     

自适应阶段变异量子粒子群优化算法研究

为了克服标准量子粒子群优化(SQPSO)算法易陷入局部最优的缺点,引入变异机制,基于进化阶段的概念,提出了自适应阶段变异量子粒子群优化(APMQPSO)算法。以四种不同的变异概率减小方式阶段性地对QPSO算法中的全局最优位置进行柯西变异,形成了四个不同的APMQPSO算法。用五个典型的测试函数进行仿真实验,并将四个APMQPSO算法与SQPSO算法的实验结果进行了比较。实验结果表明,对于单峰函数优化问题,基于变异概率线性变化的APMQPSO算法较为有效;而对于多峰函数优化问题,基于变异概率非线性变化的APMQPSO算法则具有很强的优化能力。     

改进PSO与小波的地基沉降预测应用

将改进的具有双群特性及带变异算子的粒子群优化算法与小波分析结合优化神经网络预测地基沉降量.针对粒子群算法易陷入局部极小值的缺陷,将粒子总群分成两个子群,分别对两个子群进行不同的搜索策略以增强算法的全局和局部搜索能力.其中一个子群采用变惯性权重进行局部细搜索;另一个子群采用大的惯性权重进行全局搜索,并与小波分析去噪结合,优化神经网络参数,对地基累计沉降数据进行预测.实验结果表明这种划分使算法有较强的全局和局部搜索能力,同时提高了预测精度.     

一种多策略混合的粒子群优化算法

针对传统粒子群优化算法在解决一些复杂优化问题时易陷入局部最优且收敛速度较慢的问题,提出一种多策略混合的粒子群优化算法(Hybrid Particle Swarm Optimization with Multiply Strategies,HPSO)。该算法利用反向学习策略产生反向解群,扩大粒子群搜索的范围,增强算法的全局勘探能力;同时,为避免种群陷入局部最优,算法对种群中部分较差的个体实施柯西变异,以产生远离局部极值的个体,而对群体中较好的个体施以差分进化变异,以增强算法的局部开采能力。对这3种策略进行了有机结合以更好地平衡粒子群算法全局勘探和局部开采的能力。将HPSO算法与其他3种知名的粒子群算法在10个标准测试函数上进行了性能比较实验,结果表明HPSO算法在求解精度和收敛速度上具有较显著的优势。     

基于随机自适应粒子群算法的电力系统无功优化

无功优化是保证电力系统安全经济运行的有效手段,是提高电力系统电压质量的重要措施之一。本文首先介绍无功优化的一般数学模型,然后重点分析粒子群优化算法的组成结构与工作原理,进而提出一种改进的粒子群优化算法。该算法采用随机自适应策略,能够对当前所产生的局部最优值进行变异,再重回粒子群算法中搜寻全局最优值,从而可以有效改善传统粒子群算法求解电力系统无功优化问题时存在的收敛精度不高、容易陷入局部最优等不足,一定程度上提高了粒子群算法的寻优能力。最后,通过在IEEE 30节点上进行仿真实验比较,结果表明该算法是可行和有效的,达到了提高供电质量、降低线损的目的。     

基于动态粒子群优化的网格任务调度算法*

提出了一种基于动态粒子群优化的网格任务调度算法。设计了网格任务调度问题的数学模型,给出了自适应变异的动态粒子群优化算法的框架,引入了自适应学习因子和自适应变异策略,从而使算法具有动态自适应性,能够较容易地跳出局部最优。实验结果表明,本文算法能有效地解决异构网格任务调度问题,具有较好的应用价值。     

基于改进风驱动算法的非等间距直线阵综合

针对风驱动优化(WDO)算法在解决非等间距直线阵方向图综合问题时收敛精度不高和局部寻优能力不足等缺陷,提出一种小波变异风驱动优化(WDOWM)算法,其中的小波变异算子采用随机化思想丰富了种群多样性。应用该算法综合不同数目阵元到非等间距直线阵方向图实例中,采用二阶多因素多水平的均匀设计方法确定算法参数组合。仿真结果表明,在要求低旁瓣电平和给定方向零陷的情况下,该算法的收敛精度和收敛速度均优于基本风驱动优化算法;与采用粒子群(PSO)算法优化此问题的已有文献相比,所提算法综合的效果更佳。仿真结果说明了所提算法性能良好,适用于天线阵综合问题。     

基于最优变异的粒子群优化算法

为了提高粒子群优化算法的性能,提出了一种带最优变异的改进粒子群优化算法。该算法的惯性权值满足不同粒子对全局和局部搜索能力的不同需求,每次迭代后根据适应度值会作相应的调整,在搜索过程中所引入的变异算子将对粒子群中最优粒子进行变异,以防止算法早熟收敛。对4个典型的测试函数的仿真表明,该算法比标准粒子群优化算法有更好的收敛性和更快的收敛速度。     

Particle Swarm Optimization with Chaos-based Initialization for Numerical Optimization

Particle swarm optimization (PSO) is a population based swarm intelligence algorithm that has been deeply studied and widely applied to a variety of problems. However, it is easily trapped into the local optima and premature convergence appears when solving complex multimodal problems. To address these issues, we present a new particle swarm optimization by introducing chaotic maps (Tent and Logistic) and Gaussian mutation mechanism as well as a local re-initialization strategy into the standard PSO algorithm. On one hand, the chaotic map is utilized to generate uniformly distributed particles to improve the quality of the initial population. On the other hand, Gaussian mutation as well as the local re-initialization strategy based on the maximal focus distance is exploited to help the algorithm escape from the local optima and make the particles proceed with searching in other regions of the solution space. In addition, an auxiliary velocity-position update strategy is exclusively used for the global best particle, which can effectively guarantee the convergence of the proposed particle swarm optimization. Extensive experiments on eight well-known benchmark functions with different dimensions demonstrate that the proposed PSO is superior or highly competitive to several state-of-the-art PSO variants in dealing with complex multimodal problems.     

一种自适应柯西变异的反向学习粒子群优化算法

针对传统粒子群优化算法易出现早熟的问题,提出了一种自适应变异的反向学习粒子群优化算法。该算法在一般性反向学习方法的基础上,提出了自适应柯西变异策略(ACM)。采用一般性反向学习策略生成反向解,可扩大搜索空间,增强算法的全局勘探能力。为避免粒子陷入局部最优解而导致搜索停滞现象的发生,采用ACM策略对当前最优粒子进行扰动,自适应地获取变异点,在有效提高算法局部开采能力的同时,使算法能更加平稳快速地收敛到全局最优解。为进一步平衡算法的全局搜索与局部探测能力,采用非线性的自适应惯性权值。将算法在14个测试函数上与多种基于反向学习策略的PSO算法进行对比,实验结果表明提出的算法在解的精度以及收敛速度上得到了大幅度的提高。     

Convergence analysis and performance of an improved gravitational search algorithm

Gravitational search algorithm (GSA) has been shown to yield good performance for solving various optimization problems. However, it tends to suffer from premature convergence and loses the abilities of exploration and exploitation when solving complex problems. This paper presents an improved gravitational search algorithm (IGSA) that first employs chaotic perturbation operator and then considers memory strategy to overcome the aforementioned problems. The chaotic operator can enhance its global convergence to escape from local optima, and the memory strategy provides a faster convergence and shares individual's best fitness history to improve the exploitation ability. After that, convergence analysis of the proposed IGSA is presented based on discrete-time linear system theory and results show that IGSA is not only guaranteed to converge under the conditions, but can converge to the global optima with the probability 1. Finally, choice of reasonable parameters for IGSA is discussed on four typical benchmark test functions based on sensitivity analysis. Moreover, IGSA is tested against a suite of benchmark functions with excellent results and is compared to GA, PSO, HS, WDO, CFO, APO and other well-known GSA variants presented in the literatures. The results obtained show that IGSA converges faster than GSA and other heuristic algorithms investigated in this paper with higher global optimization performance.     

自适应扩散混合变异机制微粒群算法

为了避免微粒群算法(particle swarm optimization,简称PSO)在全局优化中陷入局部极值,分析了标准PSO算法早熟收敛的原因,提出了自适应扩散混合变异机制微粒群算法(InformPSO).结合生物群体信息扩散的习性,设计了一个考虑微粒分布和迭代次数的函数,自适应调整微粒的"社会认知"能力,提高种群的多样性;模拟了基因自组织和混沌进化规律,引入克隆选择使群体最佳微粒gBest实现遗传微变、局部增值,具有变异确定性;利用Logistic序列指导gBest随机漂移,进一步增强逃离局部极值能力.基于种群的随机状态转移过程,证明了新算法具有全局收敛性.与其他几种PSO变种相比,复杂基准函数仿真优化结果表明,新算法收敛速度快,求解精度高,稳定性好,能够有效抑制早熟收敛.     

Non-parametric particle swarm optimization for global optimization

In recent years, particle swarm optimization (PSO) has extensively applied in various optimization problems because of its simple structure. Although the PSO may find local optima or exhibit slow convergence speed when solving complex multimodal problems. Also, the algorithm requires setting several parameters, and tuning the parameters is a challenging for some optimization problems. To address these issues, an improved PSO scheme is proposed in this study. The algorithm, called non-parametric particle swarm optimization (NP-PSO) enhances the global exploration and the local exploitation in PSO without tuning any algorithmic parameter. NP-PSO combines local and global topologies with two quadratic interpolation operations to increase the search ability. Nineteen (19) unimodal and multimodal nonlinear benchmark functions are selected to compare the performance of NP-PSO with several well-known PSO algorithms. The experimental results showed that the proposed method considerably enhances the efficiency of PSO algorithm in terms of solution accuracy, convergence speed, global optimality, and algorithm reliability.     

多模态函数优化的多种群进化策略

在一种使用单基因变异、精英繁殖、递减型策略参数的改进进化策略基础上,提出了一种求解多模态函数多个极值点的多种群协同进化策略,并给出了子种群进化概率、停止条件的确定和收敛到极值点的判断条件,在求多极值点的进化算法中,判别两个极值点是同峰还是异峰极值点是一个困难而关键的问题,为此引入了一种新的判别方法——山谷探索法,从而避免了确定小生境单径或峰半径,一组测试函数的仿真计算结果表明了所提出的算法能准确地找到全部极值点.     

带变异算子的非线性惯性权重PSO算法

为了克服粒子群优化算法容易陷入局部最优、早熟收敛的缺点,提出了一种带有变异算子的非线性惯性权重粒子群优化算法。该算法以粒子群算法为基础,首先采用非线性递减策略对惯性权重进行调整,平衡粒子群优化算法的全局和局部搜索能力。当出现早熟收敛时,再引入变异算子,对群体粒子的最优解做随机扰动提高算法跳出局部极值的能力。用三种经典测试函数进行测试,试验结果表明,改进算法与粒子群算法相比,能够摆脱局部最优,得到全局最优解,同时具有较高的收敛精度和较快的收敛速度。     

Multi-strategy ensemble particle swarm optimization for dynamic optimization

Optimization in dynamic environments is important in real-world applications, which requires the optimization algorithms to be able to find and track the changing optimum efficiently over time. Among various algorithms for dynamic optimization, particle swarm optimization algorithms (PSOs) are attracting more and more attentions in recent years, due to their ability of keeping good balance between convergence and diversity maintenance. To tackle the challenges of dynamic optimization, several strategies have been proposed to enhance the performance of PSO, and have gained success on various dynamic optimization problems. But there still exist some issues in dynamic optimization which need to be studied carefully, i.e. the robustness of the algorithm to problems of various dynamic features. In this paper, a new multi-strategy ensemble particle swarm optimization (MEPSO) for dynamic optimization is proposed. In MEPSO, all particles are divided into two parts, denoted as part I and part II, respectively. Two new strategies, Gaussian local search and differential mutation, are introduced into these two parts, respectively. Experimental analyses reveal that the mechanisms used in part I can enhance the convergence ability of the algorithm, while mechanisms used in part II can extend the searching area of the particle population to avoid being trapped into the local optimum, and can enhance the ability of catching up with the changing optimum in dynamic environments. The whole algorithm has few parameters that need to be tuned, and all of them are not sensitive to problems. We compared MEPSO with other PSOs, including MQSO, PHPSO and Standard PSO with re-initialization, on moving peaks Benchmark and dynamic Rastrigin function. The experimental results show that MEPSO has pretty good performance on almost all testing problems adopted in this paper, and outperforms other algorithms when the dynamic environment is unimodal and changes severely, or has a great number of local optima as dynamic Rastrigin function does.     

基于Lévy变异的微粒群算法

微粒群算法因其实现简单及优化效果较好而得到广泛应用,但也存在易早熟和局部收敛的缺点;结合Lévy飞行的特性,提出了一种新的带Lévy变异的微粒群算法,并对其收敛性进行分析,指出该算法依概率收敛于全局最优解.通过对8个标准测试函数的仿真实验,结果表明改进算法中的Lévy变异能够利用粒子的当前知识并增加群体的多样性,从而能够更有效地平衡局部搜索和全局搜索,使其具有更好的性能,最后对改进算法的各参数设置进行了探讨分析.