快速群搜索优化算法及其应用研究

在群搜索优化算法GSO(Group Search Optimize)基本原理的基础上,提出了改进的群搜索优化算法——快速群搜索优化算法QGSO(Quick Group Search Optimize),并应用于结构优化设计。算法的改进主要有3个方面:第一,当算法不前进时,适当加大游荡者的数目;第二,引进粒子群算法(PSO)的搜索方式,将GSO中的角度搜索改为步长搜索,并考虑群体最优值和个体最优值;第三,引入遗传算法,通过个体最优值与群体最优值的杂交重新生成游荡者。采用QGSO优化算法分别对平面和空间桁架结构进行了离散变量的截面优化设计,并与GSO优化算法和启发式粒子群优化算法(HPSO)的计算结果进行了比较,结果表明:该文改进的群搜索优化算法QGSO与GSO算法和HPSO算法相比具有较好的收敛精度和更快的收敛速度,可应用于工程结构的优化设计。     

快速被动群搜索优化算法及其在空间结构中的应用

在快速群搜索优化算法QGSO(quick group search optimizer)基本原理的基础上,提出了改进的快速群搜索优化算法--快速被动群搜索优化算法QGSOPC(quick group search optimizer with passive congregation),并应用于结构优化设计.采用QGSOPC优化算法分别对空间结构进行离散变量的截面优化设计,并与QGSO优化算法、群搜索优化算法GSO(group search optimize)和启发式粒子群优化算法(HPSO)的计算结果进行比较,结果表明改进的快速被动群搜索优化算法QGSOPC与QGSO算法、GSO算法和HPSO算法相比不但具有较好的收敛精度和更快的收敛速度,而且具有很好的稳定性.该算法可有效率地应用于实际结构的优化设计.     

多目标快速群搜索优化算法及在模型修正中的应用

为解决群搜索算法在求解多目标优化问题时易陷于局部最优或过早收敛,限制其在复杂结构模型修正中的应用问题,提出改进的群搜索优化算法-多目标快速群搜索优化算法(MQGSO)。采用LPS搜索方法对发现者进行迭代更新,能使发现者更快到达最优位置,提升寻优效率;对追随者增加速度更新机制,考虑其自身历史最优信息以保证收敛精度,并在算法后期采用交叉变异策略增加追随者个体多样性,避免陷入局部最优;在游荡者迭代更新中引入分量变异控制策略,增加其搜索的随机性,提高算法的全局寻优性能。通过7个典型多目标优化测试函数及某发射台有限元模型修正实例,对算法性能进行验证分析。结果表明,与已有MPSO(Multi-objective Particle Swarm Optimization)及MBFO(Multi-objective Bacterial Foraging Optimization)两种算法相比,所提MQGSO算法搜索性能更强、收敛速度更快、计算精度更高,不失为求解复杂多目标优化问题的有效方法。     

改进的细菌觅食优化算法及其在框架结构设计中的应用

在细菌觅食算法(bacterial foraging algorithm,BFA)基本原理的基础上,结合“和声搜索”算法,提出了一种改进的细菌觅食算法,并应用于框架结构优化.采用该优化算法分别对一单跨8层框架和双跨5层框架结构进行离散变量的质量优化设计,并与细菌觅食算法的计算结果进行了比较.计算结果表明改进的细菌觅食算法应用在结构优化中具有较好的收敛速度和精度,可应用于工程结构的优化设计.     

基于融合禁忌搜索粒子群算法的配电网无功优化

从数学角度分析,配电网无功优化是一个非线性、多变量、多约束的混合规划问题。粒子群优化搜索算法被广泛应用于求解配电网无功优化问题。由于粒子群算法粒子群在进化过程易趋向同一化,失去多样性,从而使算法陷入局部最优解。本文在分析配电网无功优化的特性基础上,提出一种改进的紧融合禁忌搜索-粒子群算法用于配电网无功优化问题的求解。通过将禁忌搜索功能融合到粒子历史最优解和全局最优解寻优过程中,避免了粒子群算法寻优过程中出现的局部最优问题,从而提高粒子群算法的全局搜索能力。通过IEEE14节点系统的仿真计算结果表明,改进的算法能取得良好的效果。     

基于混合动态罚函数改进协同优化算法的船舶结构静动力学优化设计

基于标准协同优化算法,针对已有改进协同优化算法的松弛因子法和罚函数法的缺陷,引入松弛因子构造混合动态罚函数改进协同优化算法,在Isight优化软件中采用了同时具备非支配排序遗传算法和自适应模拟退火算法优点的混合算法优化系统级。将改进的协同优化算法应用到船舶结构的多目标优化设计中,对船舶机舱结构的静力学和动力学特性进行优化,得到最优解并与已有的基于动态罚函数的协同优化算法结果进行比较。优化结果表明,基于混合动态罚函数改进协同优化算法的迭代次数更少,目标值更优且学科间不一致信息更小,对于实际船舶工程上的多目标多学科结构优化有一定应用价值。     

一种改进的人工蜂群算法及其在桁架几何优化设计中的应用研究

由于人工蜂群(artificial bee colony,ABC)算法存在收敛速度慢、易陷入局部最优的缺点,采用设置自适应缩放因子和基于适应度排序的选择方式代替传统的轮盘赌模型,提出了一种改进的快速人工蜂群算法(fast artificial bee colony,FABC).基于这种FABC算法对4个离散变量的几何优化模型进行了优化,并与遗传算法(GA)、蚁群算法(ACA)、启发式粒子群优化算法(HPSO)和群搜索算法(GSO)作了比较.结果表明,这种改进的人工蜂群算法具有较好的收敛精度.另外,ABC算法以及FABC算法结构简单,可应用在其他优化问题上.     

一种含最优变异的多微粒群优化算法

针对微粒群优化算法中的固有缺点，提出了带有最优变异算子的多微粒群优化算法，采用多个微粒群对目标函数进行寻优，并在寻优过程中对子群中最优微粒引入了最优变异算子。通过这样的处理，算法可以预防早熟收敛并具有更快的收敛速度和更好的局部开发能力。对一组测试函数的模拟实验结果表明，带最优变异的多微粒群优化算法可以摆脱局部最优解时微粒的吸引，在较少的代数内就能够获得好的优化结果。     

基于改进萤火虫算法优化BP神经网络的水电站厂房振动预测

利用萤火虫算法优化BP神经网络权值和阈值基础上,建立水电站厂房振动响应预测模型。针对萤火虫算法存在的收敛速度慢、易陷入局部最优等问题,引入动态随机局部搜索机制加快收敛速度,对当前最优解进行变异操作避免陷入局部最优,提出动态步长更新措施提高计算精度,改进最优解振荡问题。仿真实例表明,基于改进萤火虫算法优化的BP网络模型预测精度和收敛速度等性能得到明显改善,可用于水电站厂房结构振动响应预测。     

动力吸振器的多目标优化和多属性决策研究

在结构振动控制中,为了最大限度发挥吸振器的耗能减振作用.需要寻找吸振器的最优参数,即最优频率比、最优阻尼比和最优质量比,使得结构在不同的频率激励下获得最好的减振效果.本文将基于进化算法的多目标优化技术与多属性决策方法联合运用,针对主系统存在阻尼的减振系统,研究了动力吸振器的优化和决策同题.对于多目标优化问题,采用改进的非支配解排序的多目标进化算法(NSGA Ⅱ),求出Pareto最优解,由这些Pareto最优解构成决策矩阵,使用客观赋权的信息熵方法对最优解的属性进行权值计算.然后用逼近理想解的排序方法(TOPSIS)进行多属性决策(MADM)研究,对Pareto最优解给出排序.文中给出了4个设计参数、3个目标函数的动力吸振器优化设计算例.     

基于速度交流的多种群多目标粒子群算法研究

为提高多目标优化算法的收敛精度和搜索性能,提出一种基于速度交流的多种群多目标粒子群算法。算法引入速度交流机制,将种群划分为多个子种群以实现速度信息共享,改善粒子单一搜索模式,提高算法的全局搜索能力。采用混沌映射优化惯性权重,提高粒子搜索遍历性和全局性,为降低算法在运行后期陷入局部最优Pareto前沿的可能性,对各个子种群执行不同的变异操作。将算法与NSGA-Ⅱ、SPEA2、AbYSS、MOPSO、SMPSO和GWASF-GA先进多目标优化算法进行对比,实验结果表明:该算法得到的解集具有更好的收敛性和分布性。     

An improved imperialist competitive algorithm for multi-objective optimization

This article proposes an improved imperialistic competitive algorithm to solve multi-objective optimization problems. The proposed multi-objective imperialistic competitive algorithm (MOICA) uses the elitist strategy, based on the mutation and crossover as in genetic algorithms, and the Pareto concept to store simultaneously optimal solutions of multiple conflicting functions. Three performance metrics are used to evaluate the performance of the new algorithm: convergence to the true Pareto-optimal set, solution diversity and robustness, characterized by the variance over 10 runs. To validate the efficiency of the proposed algorithm, several multi-objective standard test functions with true solutions are used. The obtained results show that the MOICA outperforms most of the methods available in the literature. The proposed algorithm can also handle multi-objective engineering design problems with high dimensions.     

Speed Control of Motor Based on Improved Glowworm Swarm Optimization

To better regulate the speed of brushless DC motors, an improved algorithm based on the original Glowworm Swarm Optimization is proposed. The proposed algorithm solves the problems of poor robustness, slow convergence, and low accuracy exhibited by traditional PID controllers. When selecting the glowworm neighborhood set, an optimization scheme based on the growth and competition behavior of weeds is applied to a single glowworm to prevent falling into a local optimal solution. After the glowworm’s position is updated, the league selection operator is introduced to search for the global optimal solution. Combining the local search ability of the invasive weed optimization with the global search ability of the league selection operator enhances the robustness of the algorithm and also accelerates the convergence speed of the algorithm. The mathematical model of the brushless DC motor is established, the PID parameters are tuned and optimized using improved Glowworm Swarm Optimization algorithm, and the speed of the brushless DC motor is adjusted. In a Simulink environment, a double closed-loop speed control model was established to simulate the speed control of a brushless DC motor, and this simulation was compared with a traditional PID control. The simulation results show that the model based on the improved Glowworm Swarm Optimization algorithm has good robustness and a steady-state response speed for motor speed control.     

基于粒子群与聚类的多目标优化算法

针对粒子群优化算法容易陷入局部最优的问题,提出了一种基于粒子群优化与分解聚类方法相结合的多目标优化算法。算法基于参考向量分解的方法,通过聚类优选粒子策略来更新全局最优解。首先,通过每条均匀分布的参考向量对粒子进行聚类操作,来促进粒子的多样性。从每个聚类中选择一个具有最小聚合函数适应度值的粒子,以平衡收敛性和多样性。动态更新全局最优解和个体最优解,引导种群均匀分布在帕累托前沿附近。通过仿真实验,与4种粒子群多目标优化算法进行对比。实验结果表明,提出的算法在27个选定的基准测试问题中获得了20个反世代距离(IGD)最优值。     

求解约束优化问题的改进布谷鸟搜索算法

为了提高约束优化问题的求解精度和收敛速度,提出求解约束优化问题的改进布谷鸟搜索算法。首先分析了基本布谷鸟搜索算法全局搜索和局部搜索过程中的不足,对其中全局搜索和局部搜索迭代公式进行重新定义,然后以一定概率在最优解附近进行搜索。对12个标准约束优化问题和4个工程约束优化问题进行测试并与多种算法进行对比,实验结果和统计分析表明所提算法在求解约束优化问题上具有较强的优越性。     

基于PIWOA的绿色闭环供应链网络多目标模糊优化设计

针对闭环供应链网络优化设计问题,建立了一种基于Me测度的闭环供应链网络多目标优化设计模型,以此降低供应链网络设计中不确定性因素在求解时的影响。首先,针对多层级闭环供应链网络,建立以成本最小、CO₂排放量最小以及社会效益最大为目标的优化函数,并采用Me测度和三角模糊数对模型及相关约束进行模糊处理,得到不确定性闭环供应链网络优化模型;其次,在原有鲸鱼算法的基础上,引入变异收敛因子,增强其搜索能力,并将Pareto引入改进后的鲸鱼算法求解所建模型;最后,通过数值实例和仿真分析验证算法在搜索能力、时间以及优化目标函数值等方面具有较强的优势和性能。     

求解包装生产中复杂问题的布谷鸟算法改进

目的 为了解决在求解复杂的高维函数优化问题时存在的求解精度不够高和易陷入局部最优等问题,提出一种基于莱维飞行发现概率的变步长布谷鸟搜索算法(LFCS).方法 在相同环境下,选取6个不同难度、不同类型的测试函数,将LFCS算法与IPSO,IDE,IABC,CS算法比较,分析算法的收敛速度和收敛精度.结果 相比其他4种算法,LFCS算法迭代次数更少,收敛速度更快,收敛精度更高.结论 无论是低维函数还是高维函数,LFCS算法在收敛速度和收敛精度方面都有所提高,尤其是针对复杂的高维函数优化问题,在取值范围较大的情况下,LFCS算法能够更快、更准地找到最优解.     

A new optimization algorithm based on a combination of particle swarm optimization,convergence and divergence operators for single-objective and multi-objective problems

Particle swarm optimization (PSO) is a randomized and population-based optimization method that was inspired by the flocking behaviour of birds and human social interactions. In this work, multi-objective PSO is modified in two stages. In the first stage, PSO is combined with convergence and divergence operators. Here, this method is named CDPSO. In the second stage, to produce a set of Pareto optimal solutions which has good convergence, diversity and distribution, two mechanisms are used. In the first mechanism, a new leader selection method is defined, which uses the periodic iteration and the concept of the particle's neighbour number. This method is named periodic multi-objective algorithm. In the second mechanism, an adaptive elimination method is employed to limit the number of non-dominated solutions in the archive, which has influences on computational time, convergence and diversity of solution. Single-objective results show that CDPSO performs very well on the complex test functions in terms of solution accuracy and convergence speed. Furthermore, some benchmark functions are used to evaluate the performance of periodic multi-objective CDPSO. This analysis demonstrates that the proposed algorithm operates better in three metrics through comparison with three well-known elitist multi-objective evolutionary algorithms. Finally, the algorithm is used for Pareto optimal design of a two-degree of freedom vehicle vibration model. The conflicting objective functions are sprung mass acceleration and relative displacement between sprung mass and tyre. The feasibility and efficiency of periodic multi-objective CDPSO are assessed in comparison with multi-objective modified NSGAII.     

RDS-NSGA-II: a memetic algorithm for reference point based multi-objective optimization

Reference point based optimization offers tools for the effective treatment of preference based multi-objective optimization problems, e.g. when the decision-maker has a rough idea about the target objective values. For the numerical solution of such problems, specialized evolutionary strategies have become popular, despite their possible slow convergence rates. Hybridizing such evolutionary algorithms with local search techniques have been shown to produce faster and more reliable algorithms. In this article, the directed search (DS) method is adapted to the context of reference point optimization problems, making this variant, called RDS, a well-suited option for integration into evolutionary algorithms. Numerical results on academic test problems with up to five objectives demonstrate the benefit of the novel hybrid (i.e. the same approximation quality can be obtained more efficiently by the new algorithm), using the state-of-the-art algorithm R-NSGA-II for this coupling. This represents an advantage when treating costly-to-evaluate real-world engineering design problems.     

Pareto layer: Its formulation and search by way of evolutionary multi-objective optimization

This article examines multi-objective problems where a solution (product) is related to a cluster of performance vectors within a multi-objective space. Here the origin of such a cluster is not uncertainty, as is typical, but rather the range of performances attainable by the product. It is shown that, in such cases, comparison of a solution to other solutions should be based on its best performance vectors, which are extracted from the cluster. The result of solving the introduced problem is a set of Pareto optimal solutions and their representation in the objective space, which is referred to here as the Pareto layer. The authors claim that the introduced Pareto layer is a previously unattended novel representation. In order to search for these optimal solutions, an evolutionary multi-objective algorithm is suggested. The article also treats the selection of a solution from the obtained optimal set.