求解复杂优化问题的双层多种群粒子群优化算法

为解决粒子群优化算法存在的易早熟和精度低问题,提出了一种双层多种群粒子群优化算法.此算法采用上下两层,即下层N个基础种群和上层一个精英种群.各个基础种群相互独立进化,并从精英种群中得到优良信息指导自己的进化.上层精英种群首先通过接受各基础种群的当前最优粒子来更新自己的粒子集合,然后执行自适应变异操作,最后随机地向每一个基础种群输送出本次进化后的一个最优粒子来改进其下一轮搜索.该算法的并行双进化机制增加了群体的随机性和多样性,提高了全局搜索能力和收敛精度.实例仿真表明该算法具有较好的性能,尤其对于复杂多峰函数优化,成功率显著提高.     

改进的思维进化算法在阵列天线综合中的应用

思维进化算法(Mind Evolutionary Algorithm,MEA)采用趋同和异化操作,通过模仿人类思维进化的过程进行寻优,克服了早熟现象,提高了算法的搜索能力.针对基本思维进化算法中产生初始种群的盲目性、补充淘汰临时子群体的单一性以及现有搜索方式易陷入小区域局部收敛的问题,提出了一种多混沌思维进化算法.该算法采用两种不同的混沌序列,提高了种群的多样性,扩大了搜索范围.将多混沌思维进化算法应用于等间距直线阵列天线综合.良好的仿真结果表明了多混沌思维进化算法在阵列天线综合的优越性.     

应用蜜蜂繁殖进化型粒子群算法求解车辆路径问题

为了提高粒子群算法求解车辆路径问题时收敛速度和全局搜索能力,将蜜蜂繁殖进化机制与粒子群算法相结合,应用到CVRP问题的求解。该算法中,最优的个体作为蜂王与通过选择机制选择的雄蜂以随机概率进行交叉,增强了最优个体信息的应用能力;同时,随机产生一部分雄蜂种群,并将其与蜂王交叉增加了算法的多样性。实例分析表明该算法具有较好的全局搜索能力,验证了该算法的可行性。     

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。     

基于粒子群算法求解约束优化问题的改进算法

提出一种进行的粒子群算法(Particle Swarm Optimization,PSO)用于求解多目标的优化问题。这种改进引入遗传算法的交叉算子,增强算法的搜索能力。同时,使用基于子种群划分的改进选择算子,避免算法过早陷入局部最优。使用三个测试函数进行测试,实验结果证明算法的有效性。     

基于速度交流的共生多种群粒子群算法

为了提高粒子群算法的求解精度,改善算法的搜索性能,提出一种基于速度交流的共生多种群粒子群算法(SMPSO)。该算法采用速度交流机制划分整个从种群为多个子种群,负责解空间的全局搜索,将获得的最优信息分享给主种群;主种群综合从种群与自身最优经验,负责局部深度优化,获得最优信息反馈给从种群,从而建立主从群间的共生关系,实现解空间的充分搜索。迭代后期,在主种群中引入自适应变异策略,提高算法跳出局部最优的能力。将提出的SMPSO算法应用于基准测试函数中,与其它改进的PSO算法进行比较。实验结果表明,SMPSO算法在求解精度、搜索能力、稳定性等方面均有较大的提高。     

自动化生产单元调度的混沌粒子群算法

在求解一类带时间窗口的自动化生产单元调度问题时,基本粒子群算法易陷入局部极值点且收敛缓慢.针对这一问题,将混沌搜索技术引入至基本粒子群算法中,利用混沌运动搜索精度高、遍历性好的特点来改善基本粒子群算法易陷入局部极值点和收敛缓慢的缺点,从而提高粒子群算法的收敛速度和优化质量.首先给出了带时间窗口的自动化生产单元调度问题的混合整数规划模型,着重讨论了混沌粒子群调度算法的设计,包括编码方式、混沌初始化、混沌扰动和适应度函数计算等.对提出的算法进行了仿真验证,仿真结果表明在求解此类调度问题上,混沌粒子群算法比基本粒子群算法具有明显的优势.     

基于关节层次模型的3D手臂运动快速跟踪算法

针对人体3D运动跟踪过程中计算效率低下的问题,提出了基于粒子滤波和关节层次模型的3D手臂运动快速跟踪算法.该算法在经典的人体3D骨骼模型的基础上,提出了关节层次模型,利用关节层次模型将高维手臂运动状态参数空间分解为若干个低维参数子空间,最后,在关节层次模型的约束条件下,根据自顶向下的搜索策略,利用粒子滤波算法对手臂运动进行跟踪,从而减少了跟踪所需的粒子数目.实验表明,与标准的粒子滤波算法相比,该算法能够在保证跟踪精度的同时,提高计算效率.     

基于聚类的粒子群优化算法在MES调度中的应用

针对传统调度算法寻优效率低的弱点,从MES功能出发,将其调度功能单独抽出,提出了基于聚类的粒子群优化算法,将聚类用于粒子群搜索空间的改进.仿真结果表明了该算法的有效性.     

基于粒子群遗传算法的泊车系统路径规划研究

针对智能停车库自动导引运输车(automated guided vehicle,AGV)存取车路径规划问题,提出了一种基于粒子群和遗传算法的动态自适应混合算法.在标准粒子群算法和遗传算法的基础上,通过引入动态自适应调整策略分别对惯性权重系数、学习因子以及交叉变异概率公式进行了优化.在进化初期,通过在惯性权重系数和学习因子之间建立动态联动关系来实现对粒子速度和位置的实时有效更新;在进化后期,通过引入自适应遗传算法的交叉、变异操作来增强混合算法的全局搜索能力,提高算法的进化速度和收敛精度.为验证混合算法的可行性和有效性,选用MATLAB软件对其进行仿真测试.仿真测试结果显示,与禁忌搜索算法、蚁群算法以及遗传算法相比,混合算法表现出较强的全局搜索能力和较好的收敛性能,表明混合算法可行和有效.     

大悬浮轻颗粒固液两相流中的有序结构

应用三维颗粒图像跟踪技术,对竖直管内向上大悬浮轻颗粒固液两相流中分散相即颗粒相瞬时分布进行非接触测量,由此对顺流方向颗粒串组成的有序相分布结构进行观察研究。实验发现,当液体流动速度大于某一确定值时会有明显的颗粒串出现,此时颗粒由于受液体速度梯度诱导的强升力作用而紧贴管壁运动;随着液体流动速度的降低,颗粒串逐渐消失而颗粒沿管径向的分布会向着管中心方向发展;当液流速度进一步降低,颗粒开始在水平方向团聚。分析表明液体流动的剪切作用是颗粒串生成和稳定的机制。实验还显示,随着颗粒相平均份额的增加,流动中串间颗粒的相互作用加强,颗粒分布结构也随之受到影响。     

Coupled finite particle method with a modified particle shifting technology

The conventional SPH method has been frustrated with the low accuracy originated from the particle inconsistency. The finite particle method (FPM) is an improved SPH method with a higher‐order accuracy. However, the numerical accuracy and stability of FPM depend on the uniformity of particles. Facing the disorder particles, the conventional FPM may suffer from an ill‐conditioned corrective matrix and is difficult to conduct longtime simulations. A popular and robust particle regularization scheme is the so‐called particle shifting technology (PST), which can effectively enhance the accuracy and stability of particle methods. In the context of FPM, PST is analyzed and discussed, and a modified PST (MPST) is proposed. Modified PST saves great amount of computational cost with respect to the conventional PST and acquires better features of accuracy and stability. Finally, the coupled FPM method by combining MPST and δ‐SPH is developed to simulate a series of viscous flows. The numerical results indicate that MPST is effective in improving accuracy, stability, and efficiency of PST, and the coupled FPM is shown to be robust for simulating viscous flows and has a higher accuracy and stability.     

Measurement and Control of Triboelectrically Charged Silica and Glassy Carbon Particles

In this study, a particle trajectory analysis and charging measurements of triboelectrically charged silica and glassy carbon particles were conducted to investigate the effects of charging gas velocity and particle size on triboelectrical charging characteristics. A particle motion analysis system (PMAS) was used to measure charged particle motion information in the separation chamber with an applied uniform electric field, and the particle charging amount was calculated from the particle size and the electrostatic mobility was determined by the PMAS. The test system consisted of a particle generator, a spiral-type tribocharger made of a copper tube, and a particle motion analysis system to measure the particle size and velocity. The experiments were conducted with test particles of silica and glassy carbon and the average charging gas velocities of 6, 10, 15, 20 m/s to analyze the effect on particle charging. As a result, the silica and glassy carbon particles acquired negative and positive charges, respectively, due to the differences in the work functions, and the charging gas velocity effect on particle charge was approximately linear with an increasing velocity yielding a higher average particle charge and wider distribution.     

Measurement and Control of Triboelectrically Charged Silica and Glassy Carbon Particles

In this study, a particle trajectory analysis and charging measurements of triboelectrically charged silica and glassy carbon particles were conducted to investigate the effects of charging gas velocity and particle size on triboelectrical charging characteristics. A particle motion analysis system (PMAS) was used to measure charged particle motion information in the separation chamber with an applied uniform electric field, and the particle charging amount was calculated from the particle size and the electrostatic mobility was determined by the PMAS. The test system consisted of a particle generator, a spiral-type tribocharger made of a copper tube, and a particle motion analysis system to measure the particle size and velocity. The experiments were conducted with test particles of silica and glassy carbon and the average charging gas velocities of 6, 10, 15, 20 m/s to analyze the effect on particle charging. As a result, the silica and glassy carbon particles acquired negative and positive charges, respectively, due to the differences in the work functions, and the charging gas velocity effect on particle charge was approximately linear with an increasing velocity yielding a higher average particle charge and wider distribution.     

悬浮法高分子量聚乙烯树脂的颗粒特性研究

采用扫描电镜，图像分析，ＣＣｌ４吸收，表面孔径测定以及增塑剂吸收量测定方法研究了新型ＨＭＷＰＶＣ树脂的颗粒特性和增塑剂吸收性能。结果表明，国产ＨＭＷＰＶＣ树脂颗粒疏松多孔，增塑剂吸收程度优于通用型ＰＶＣ树脂，但其总体颗粒特性又较日本同类产品为差。同时，提出了ＨＭＷＰＶＣ的颗粒结构模型。     

金属陶瓷功能梯度材料的颗粒界面断裂能量释放率与临界颗粒尺寸的研究

研究了功能梯度材料富陶瓷区金属颗粒界面断裂能量释放率。文中采用双层嵌套模型给出了金属颗粒界面的热应力与金属体积浓度的关系, 对于得到的每一梯度层中的颗粒界面热应力, 分析了颗粒界面断裂能量释放率,并研究了每一梯度层中金属颗粒的临界尺寸变化规律。     

基于微粒群优化的模型参考自适应控制

针对复杂非线性对象提出了一种基于微粒群优化(PSO)的PID自适应控制方法.通过运用PSO算法对PID控制器参数进行在线调整,使模型参考自适应控制达到理想的控制效果.将该方法引入到连续搅拌反应釜这一复杂的非线性系统,仿真结果表明了该方法的良好性能.     

超微粒子设计技术及应用

本文综述了目前进行微粒子设计的几种主要方法 ,并对设计出的各种具有不同功能的超微粒子的应用作了介绍     

超细金属微粒及其复合聚合物的研究进展

超细金属微粒作为材料科学中的重要一员，因其具有特殊的物化性质，其与聚合物相结合的研究近年来受到科学家们广为关注。本文拟从超细金属微粒的性质、超细金属微粒聚合物体系结构与性能、制备方法及应用等方面作综合评述。     

Effect of crystallization parameters and presence of aqueous extract of Nigella Sativa on growth inhibition of calcium oxalate monohydrate particles

For the first time, nucleation kinetics, crystal growth and agglomeration of calcium oxalate monohydrate (COM) are studied as a crystal growth inhibitor with and without Nigella Sativa(NS) extract. The induction period was determined under different supersaturation ratios ranging from 1.63 to 4.51 at 37°C using the conductivity method. Based on the classical homogeneous nucleation theory; the critical nucleation parameters were evaluated at higher supersaturation ratio. The calculated surface energy was increased from 7.97?mJ/m² without additive to 10.31?mJ/m² with NS extract. However, the nucleation rate at a supersaturation ratio of 3.26 corresponding to 5.44 with the NS extract was decreased from 3.9?×?10²⁹ nuclei/cm³.s (without additive) to 1.3?×?10²⁹ nuclei/cm³.s with NS extract addition. The number of molecules required for the formation of a stable nucleus was calculated with and without NS extract at different supersaturation ratios. The crystallite sizes of the formed crystals without and with the additive are 93 and 51?nm, respectively. Scanning electron microscopy (SEM) photomicrographs show the formation of small crystals and less aggregated with the NS inhibitor compared with the baseline (without the inhibitor). This study can help us with a clear understanding of the inhibition mechanism of an aqueous NS extract on COM crystals.