A hybrid swarm population of Pinus densiflora × P. sylvestris inferred from sequence analysis of chloroplast DNA and morphological characters

To confirm a hybrid swarm population of Pinus densiflora × P. sylvestris in Jilin, China, we used needles and seeds from P. densiflora, P. sylvestris, and P. densiflora × P. sylvestris collected from natural stands or experimental stations to study whether shoot apex morphology of 4-year old seedlings can be correlated with the sequence of a chloroplast DNA simple sequence repeat marker （cpDNA SSRs）. Total genomic DNA was extracted and subjected to sequence analysis of the pine cpDNA SSR marker Pt15169. Results show that morphological characters from 4-year old seedlings did not correlate with sequence variants of this marker. Marker haplotypes from all P. sylvestris trees had a CTAT element that was absent from all sampled P. densiflora trees. However, both haplotype classes involving this insertion/deletion element were found in a P. densiflora × P. sylvestris population and its seedling progeny. It was concluded that the P. densiflora × P. sylvestris accessions sampled from Jilin, China resulted from bi-directional crosses, as evidenced by both species’ cpDNA haplotypes within the hybrid swarm population.

Joint waveform selection and power allocation algorithm in manned/unmanned aerial vehicle hybrid swarm based on chance-constraint programming

In this paper, we propose a joint waveform selection and power allocation(JWSPA) strategy based on chance-constraint programming(CCP) for manned/unmanned aerial vehicle hybrid swarm(M/UAVHS) tracking a single target. Accordingly,the low probability of intercept(LPI) performance of system can be improved by collaboratively optimizing transmit power and waveform. For target radar cross section(RCS) prediction, we design a random RCS prediction model based on electromagnetic simulation(ES) of target. For waveform selection, we build a waveform library to adaptively manage the frequency modulation slope and pulse width of radar waveform. For power allocation,the CCP is employed to balance tracking accuracy and power resource. The Bayesian Cramér-Rao lower bound(BCRLB) is adopted as a criterion to measure target tracking accuracy. The hybrid intelli gent algorithms, in which the stochastic simulation is integrated into the genetic algorithm(GA), are used to solve the stochastic optimization problem. Simulation results demonstrate that the proposed JWSPA strategy can save more transmit power than the traditional fixed waveform scheme under the same target tracking accuracy.

Traveling Salesman Problem Using an Enhanced Hybrid Swarm Optimization Algorithm

The traveling salesman problem( TSP) is a well-known combinatorial optimization problem as well as an NP-complete problem. A dynamic multi-swarm particle swarm optimization and ant colony optimization( DMPSO-ACO) was presented for TSP.The DMPSO-ACO combined the exploration capabilities of the dynamic multi-swarm particle swarm optimizer( DMPSO) and the stochastic exploitation of the ant colony optimization( ACO) for solving the traveling salesman problem. In the proposed hybrid algorithm,firstly,the dynamic swarms,rapidity of the PSO was used to obtain a series of sub-optimal solutions through certain iterative times for adjusting the initial allocation of pheromone in ACO. Secondly,the positive feedback and high accuracy of the ACO were employed to solving whole problem. Finally,to verify the effectiveness and efficiency of the proposed hybrid algorithm,various scale benchmark problems were tested to demonstrate the potential of the proposed DMPSO-ACO algorithm. The results show that DMPSO-ACO is better in the search precision,convergence property and has strong ability to escape from the local sub-optima when compared with several other peer algorithms.

A Hybrid Particle Swarm Optimization to Forecast Implied Volatility Risk

The application of optimization methods to prediction issues is a continually exploring field.In line with this,this paper investigates the connectedness between the infected cases of COVID-19 and US fear index from a forecasting perspective.The complex characteristics of implied volatility risk index such as non-linearity structure,time-varying and nonstationarity motivate us to apply a nonlinear polynomial Hammerstein model with known structure and unknown parameters.We use the Hybrid Particle Swarm Optimization(HPSO)tool to identify the model parameters of nonlinear polynomial Hammerstein model.Findings indicate that,following a nonlinear polynomial behaviour cascaded to an autoregressive with exogenous input(ARX)behaviour,the fear index in US financial market is significantly affected by COVID-19-infected cases in the US,COVID-19-infected cases in the world and COVID-19-infected cases in China,respectively.Statistical performance indicators provided by the developed models show that COVID-19-infected cases in the US are particularly powerful in predicting the Cboe volatility index compared to COVID-19-infected cases in the world and China(MAPE(2.1013%);R2(91.78%)and RMSE(0.6363 percentage points)).The proposed approaches have also shown good convergence characteristics and accurate fits of the data.

Hybrid optimization algorithm based on chaos,cloud and particle swarm optimization algorithm

As for the drop of particle diversity and the slow convergent speed of particle in the late evolution period when particle swarm optimization（PSO） is applied to solve high-dimensional multi-modal functions,a hybrid optimization algorithm based on the cat mapping,the cloud model and PSO is proposed.While the PSO algorithm evolves a certain of generations,this algorithm applies the cat mapping to implement global disturbance of the poorer individuals,and employs the cloud model to execute local search of the better individuals;accordingly,the obtained best individuals form a new swarm.For this new swarm,the evolution operation is maintained with the PSO algorithm,using the parameter of pop distr to balance the global and local search capacity of the algorithm,as well as,adopting the parameter of mix gen to control mixing times of the algorithm.The comparative analysis is carried out on the basis of 4 functions and other algorithms.It indicates that this algorithm shows faster convergent speed and better solving precision for solving functions particularly those high-dimensional multi-modal functions.Finally,the suggested values are proposed for parameters pop distr and mix gen applied to different dimension functions via the comparative analysis of parameters.

Optimization of Thermal Aware VLSI Non-Slicing Floorplanning Using Hybrid Particle Swarm Optimization Algorithm-Harmony Search Algorithm

Floorplanning is a prominent area in the Very Large-Scale Integrated (VLSI) circuit design automation, because it influences the performance, size, yield and reliability of the VLSI chips. It is the process of estimating the positions and shapes of the modules. A high packing density, small feature size and high clock frequency make the Integrated Circuit (IC) to dissipate large amount of heat. So, in this paper, a methodology is presented to distribute the temperature of the module on the layout while simultaneously optimizing the total area and wirelength by using a hybrid Particle Swarm Optimization-Harmony Search (HPSOHS) algorithm. This hybrid algorithm employs diversification technique (PSO) to obtain global optima and intensification strategy (HS) to achieve the best solution at the local level and Modified Corner List algorithm (MCL) for floorplan representation. A thermal modelling tool called hotspot tool is integrated with the proposed algorithm to obtain the temperature at the block level. The proposed algorithm is illustrated using Microelectronics Centre of North Carolina (MCNC) benchmark circuits. The results obtained are compared with the solutions derived from other stochastic algorithms and the proposed algorithm provides better solution.

基于混合粒子群算法的波浪能发电集群优化方法

对波浪能发电集群的优化控制有助于波浪能的有效利用,为此文章提出了基于混合粒子群算法的波浪能发电集群优化方法。以直驱式发电装置为研究对象,探讨其构成发电集群短期尺度下稳定状态的数学模型,由简至繁依次考虑波浪动态压力、装置间辐射影响和遮挡效应,以便更准确地模拟一定密集度的波浪能发电装置部署下的实际效果。以集群功率最大化为优化目标,根据装置运动和海域能量约束,提出混合粒子群算法求解集群的最优参数,在传统算法基础上设定自适应惯性权重并加入交叉和变异操作,以应对复杂集群方程解空间的多峰性问题。算例结果验证了所述集群优化方法的有效性,求解质量良好;同时表明波浪能发电集群规模越大,装置之间的辐射影响越复杂,遮挡效应越明显。

运输能力受限下分段建造的时空调度问题

分段建造作为船舶整个建造流程的关键环节之一,其空间资源和时间资源的动态协调性严重影响着船舶建造周期和订单交付。针对分段建造船体车间空间有限、时间组织和空间组织不协调,以及以往分段建造时空调度相关研究忽略运输能力限制等问题,以最大完工时间最小、总提前与延期惩罚值最小为优化目标,以空间大小、加工小组的异质性、运输设备的差异性与运输限制为约束条件,构建多目标时空调度模型,并基于交付期优先规则、空间定位规则和关键阻碍规则提出混合粒子群算法进行求解,最终以某船厂分段建造为例进行实例验证,结果表明:所提出的模型与算法有效降低了分段完工时间,提高了分段建造的准时化水平。研究结可为船舶智能制造以及分段制造执行系统(MES)的实际应用提供一种方法基础。

基于PSO与AFSA的GNSS整周模糊度种群融合优化算法

载波相位测量是实现全球导航卫星系统(Global navigation satellite system, GNSS)快速高精度定位的重要途径,而准确解算整周模糊度是其中的关键步骤之一.粒子群算法(Particle swarm optimization, PSO)收敛速度快但易陷入局部最优,人工鱼群算法(Artificial fish swarm algorithm, AFSA)全局优化性能好但收敛速度慢,因此融合两种算法的优点,提出一种GNSS整周模糊度种群融合优化算法(PSOAF).首先,通过载波相位双差方程求解整周模糊度的浮点解和对应的协方差矩阵.然后,采用反整数Cholesky算法对模糊度浮点解作降相关处理.其次,针对整数最小二乘估计的不足通过优化适应度函数来提高算法的收敛性和搜索性能.最后,通过PSOAF算法对整周模糊度进行解算.通过经典算例和试验研究表明:PSOAF算法可以更快地收敛于最优解,搜索效率也更为出色,解算的基线精度可以控制在10 mm以内,在短基线的实际情况下具有较高的应用价值.

无人机17kW电机振动噪声分析与巡航转速下尖端噪声优化

随着无人机的迅速发展,噪声问题影响消费者体验及AI交互、语音识别等技术,限制了无人机应用潜力。该文针对一台17 kW无人机用外转子永磁同步电机进行研究。为降低电机尖端振动噪声,且保留原电机电磁性能,重点提出优化磁极和定子开槽的方法。具体以平均转矩、转矩脉动等作为约束条件,构建多目标优化数学模型,并利用混合粒子群优化算法求解。该文深入探讨磁极参数、定子开槽对低阶次径向气隙磁通密度空间谐波特征的影响。并对电机转子模态仿真,以研究径向电磁力与空间模态的作用机理。在多转速情况下,以巡航转速为重点,分析整体电机电磁振动噪声特征。最后,仿真和实验结果表明,电机在巡航转速下的尖端噪声显著减小。验证了优化结构对无人机电机尖端振动噪声有明显抑制作用,对解决无人机噪声问题具有重要意义。

基于遗传算法特性的混合粒子群算法求解TSP问题

为解决粒子群算法在旅行商问题上的收敛速度慢和路径最优化选择的问题,提出了一种新型的基于遗传算法特性的混合粒子群算法,对旅行商问题的最优路径进行规划.根据种群比例原则与迭代前的路径进行交叉、变异、复制等操作,建立了具有遗传算法特性的混合粒子群算法,并用于求解burma14问题.结果表明:相比传统的粒子群算法和模拟退火-禁忌搜索算法,混合粒子群算法在求解burma14问题中收敛时间与最优路径等指标上都有明显的优势,且随着迭代次数与种群个数的增大,算法的最优解逐渐减小;当最佳参数为种群个数150,迭代次数300时,最优解为30.179 424.

基于CSA-AFSA算法的集装箱港口连续型泊位分配优化

为提升集装箱港口运营效率,笔者研究了考虑潮汐因素与泊位偏好的连续型泊位分配问题。引入了船舶时空矩形不可重叠约束和潮汐时间窗约束,构建以最小化船舶等待、延迟离港、泊位偏离以及在港期间油耗费用和最小为目标的混合整数线性规划模型;根据模型特征,采用CPLEX求解软件、鱼群算法、布谷鸟搜索算法和布谷鸟鱼群混合算法进行求解,以计划周期为36 h的20个不同规模的船舶到港数据为研究算例,通过算例求解得到符和潮汐时间窗、泊位偏好等要求的泊位分配方案。算例求解表明:算例规模较小时,CPLEX可以在较短时间内求出最优泊位分配方案;算例规模较大时,CPLEX求解时间较长,布谷鸟鱼群混合算法可以在平均3 min内求出与CPLEX差距为0.39%~4.20%的次优解;不同算法间的对比表明,布谷鸟鱼群混合算法求解能力更优,混合算法所得泊位分配方案中,乘潮船舶的进出港时刻均在潮汐高水位时段,且85%以上的船舶在偏好泊靠点200 m内接受装卸服务。

基于多种群多策略的竞争粒子群算法

针对标准粒子群算法遇到的易陷入局部最优、收敛差、求解精度低等问题,提出了多种群多策略竞争粒子群优化算法.新算法将每一代粒子根据适应度排序,将其划分为不同的子种群,并引入非线性Logistic混沌映射权重、收缩因子和混合高斯-柯西扰动机制来更新这些子种群.使用不同的粒子更新方式平衡了算法整个时期的全局搜索和局部开发能力,从而加快了收敛速度.最后,将多种群多策略竞争粒子群优化算法与标准粒子群算法和其它优化算法在11个测试函数上进行对比,结果表明,新算法在跳出局部最优解、和寻优精度方面显著优于标准粒子群算法,且有更快的收敛速度.在寻优能力和算法稳定性上大幅度强于其它对比算法.

基于改进粒子群算法的木材板材下料方法

木材板材在家具行业应用广泛,以绿色环保、节约能源为目的的木材板材优化下料已经成为研究的热点。木材板材下料优化问题属于二维矩形下料问题,是一种具有高度计算复杂性的问题。本研究主要针对单规格木材板材进行矩形零件下料问题,在木材板材长和宽都大于零件长和宽的情况下,通过建立二维下料的数学模型,采用标准粒子群算法、变邻域搜索算法、粒子群混合变邻域搜索算法分别进行求解,并以某企业的下料实例进行分析计算。首先,利用标准粒子群算法求解单规格板材下料问题;其次,利用变邻域搜索算法求解单规格板材下料问题。在获得局部最优解的基础上改变其邻域结构再进行局部搜索,找到另一个局部最优解,如此不断迭代,直到满足算法的终止条件,获得全局最优解;最后,利用粒子群变邻域搜索混合算法求解单规格板材下料问题。针对粒子群算法局部搜索能力较差、容易过早收敛的问题和具有较好包容性的特点,将变邻域搜索的思想融入粒子群算法中,使结果更加趋向全局最优。结果表明:粒子群变邻域搜索混合算法相比粒子群算法和变邻域算法效率都有显著提升,能显著提高该木材板材的利用率,增加企业经济效益。

考虑能耗和运输的有限缓冲区混合流水车间调度

为解决生产调度不及时、加工过程中能耗过大等问题,构建了有限缓冲区混合流水车间调度优化模型。模型以最小化最大完工时间和车间总能耗为目标,将运输时间、广义能耗和缓冲区容量等资源限制作为约束,并应用开关机节能策略减少待机能耗,验证了优化模型的可行性;设计一种狮群算法,采用随机产生与贪婪选择相结合的种群初始化方法,提高初始解质量和求解效率,验证了狮群算法的优越性。实验结果表明:该算法能有效解决考虑能耗和运输时间的有限缓冲区混合流水车间调度问题,优化模型能依照实际需要进行柔性调节,达到制造型企业合理排产、节能减排的目的。

基于分组学习粒子群算法的众包软件项目调度

为解决众包软件项目调度问题中的开发者选择、任务分配和投入度确定3个强耦合子问题,引入开发者信誉度,考虑技能、工作时长、开发团队规模等约束,以项目完成质量和工期为目标建立数学模型。提出一种采用三段式混合编码的分组学习粒子群算法求解所建模型。所提算法根据适应度排序将种群划分为3组,不同分组的粒子数量随进化代数自适应变化,且各组根据不同的适应度采用不同的更新策略。将所提算法与10种具有代表性的算法在12个不同规模的众包软件项目调度算例中进行对比,结果表明,所提算法能够获得精度更高的调度方案。

基于风光互补发电系统的压缩空气混合储能系统容量优化

压缩空气储能系统可以有效减少因风能和太阳能随机性造成的弃风弃光现象,但其动态响应时间长,且存储规模配置不合理会影响其发展。为此首先提出液流电池与压缩空气储能组成混合储能系统解决并网型风光互补发电系统输出波动不稳定的问题;其次基于典型小时负荷、风力机发电功率和光伏发电功率,针对不同场景,以系统最大收益为目标函数,利用猫群算法优化压缩空气储能系统的容量配置;最后分析压缩空气储能系统的额定容量与额定功率对系统最大收益的影响,验证算法可靠性。结果表明,基于风力机与光伏系统的装机功率分别为20 MW和3.42 MW的场景,压缩空气储能系统容量配置为4 MW和46.5 MW∙h时,其经济性最佳,每周可节约购电成本183688.24元,周最大收益为30543.86元。

无人机遥感反演小麦地上生物量模型的特征选择

无人机多光谱技术能快速、无损地测定小麦地上生物量(AGB)。然而,多光谱方法在计算植被特征时会产生大量具有高度相关的重复特征。因此,建立结构简单、精度高的模型对特征进行筛选具有重要意义。本文提出了一种可以同时实现特征筛选与参数优化的混合编码灰狼粒子群优化算法(CGWOPSO)。同时,为评估基于该算法驱动的极限梯度提升模型(CGWOPSO-XGB)的性能,将其及基于两种流行特征筛选方法(Pearson和SHAP方法)的模型(P-XGB和S-XGB)的反演AGB表现进行了对比。结果表明,S-XGB模型优于P-XGB模型,前者均方根误差(RMSE)比后者低3.0%~16.3%;而CGWOPSO-XGB模型精度高于S-XGB模型,前者RMSE比后者低16.0%。

基于差分进化粒子群混合算法的多无人机协同区域搜索策略

为提高无人机群在未知环境中的区域搜索效率,提出一种多无人机协同区域搜索策略。首先,根据区域搜索任务需求,建立包含区域覆盖率、区域不确定度、目标存在概率三种属性的区域信息地图;其次,以最大化搜索效率、同时最小化无人机搜索过程中的能耗为目标,建立无人机区域搜索滚动时域优化目标函数,指导无人机在线决策搜索路线;然后针对传统群智能优化算法易陷入局部最优的缺陷,设计差分进化粒子群混合算法在线求解该多目标优化问题,提高算法的寻优性能,从而提高无人机的搜索效率。最后,通过数值仿真实验,对所提算法进行验证,仿真结果表明,文中设计的基于差分进化粒子群混合算法的多无人机协同区域搜索策略与传统的群智能优化算法相比具有更高的区域搜索效率。

基于SCSO-SVM算法的光伏组件故障识别

光伏阵列通常被安装在恶劣的室外环境中,因此在运行过程中易发生故障。为了准确识别光伏阵列的故障类型,提出沙猫群优化支持向量机(sand cat swarm optimization support vector machine,SCSO-SVM)用于光伏组件故障识别,且对比支持向量机(support vector machine,SVM)、粒子群优化支持向量机(particle swarm optimized support vector machine,PSO-SVM)、遗传优化支持向量机(genetic optimized support vector machine,GA-SVM)、麻雀优化支持向量机(sparrow optimized support vector machine,SSA-SVM)、灰狼优化支持向量机(gray wolf optimized support vector machine,GWO-SVM)和鲸鱼优化支持向量机(whale optimized support vector machine,WOA-SVM)算法。首先,六种SVM混合算法都克服了SVM诊断结果易受参数初始值影响的缺点,识别精度相较传统SVM算法都有所提升,但是识别时间都增加。其次,7种算法中SCSO-SVM识别效果最好,克服了SVM易受参数初始值的影响,相较SVM识别精度提高了约9.4594%;是因为更能有效找到SVM惩罚因子和核函数参数。然后,对于同一种算法而言,算法的识别精度是随输入特征减少而降低的,是因为输入特征越少,越不能有效表征光伏组件在不同故障类型下的输出属性。但算法的识别时间却不是随输入特征减少而减短。所以选取合适的输入特征才能兼顾算法的故障识别准确率和效率。最后,发现七种算法的识别效果依赖于数据集的影响。原因可能是各个算法参数选择过多导致泛化性有差异,且依赖参数初始值选择。