考虑Pareto最优的列车运行图与维修天窗协调优化

列车运行图与维修天窗之间的冲突始终无法避免,且维修天窗开设时间的长短显著影响列车总运行时间。针对此问题,综合考虑维修天窗对列车运行造成的限速约束、车站到发线数量约束等,建立列车总运行时间最小,以及维修天窗实际开设时长与理想时长总偏差最小的双目标混合整数规划模型;对困难约束设置中间辅助变量将模型线性化以提高求解效率,并设计约束转换算法求解双目标模型的Pareto最优;微观化处理铁路线,将站内资源和站间资源细化为一系列行车资源单元,得到更加符合实际旅客运输需求的运行图。以某地区铁路线夜间开行列车及维修天窗开设计划为研究背景,调用商业软件求解双目标函数模型的Pareto最优,并对双目标模型的最小支配解和最优支配解进行对比分析;针对最优支配解下的列车进入、离开行车资源单元的时间、停站作业时间及维修天窗的开始时间及开设时长,绘制列车运行图。求解结果表明:模型在满足维修天窗最小开设时长的同时,能够兼顾列车运行总时间最小和维修天窗开设时长更充裕。基于最优支配解绘制的列车运行图表明:微观路网下的列车运行时刻表优化结果更符合实际旅客运输生产作业需要。研究结果可为铁路运营管理部门进一步优化列车运行图编制与维修天窗开设提供参考。

基于Pareto蚁群算法的双目标路径规划研究

针对复杂建筑环境人员应急疏散单一路径不能满足火灾环境变化需求的问题,基于改进蚁群算法,结合Pareto双目标解集思想,提出一种组合优化解集的双目标蚁群算法,通过排序优化的思想,实现人员多路径动态疏散规划。在构造Pareto解集的阶段协同考虑疏散路径长度以及火灾风险程度2个优化目标,计算各个解之间的支配关系。利用排序优化蚁群算法的正反馈机制将各组解的信息素按一定比例作为最优路径信息素的积累,加快解集的寻找。最后将其与传统双目标蚁群算法相比较,结果表明:优化后的双目标算法更加适合复杂建筑人员疏散路径规划问题,在寻找多组满足要求解的同时展示目标之间的利弊关系,供决策者选择合适的路径,提高疏散效率。

面向供应链分销的多维空间Pareto边界自动谈判模型研究

随着电子商务的快速发展,自动谈判逐渐成为提升供应链系统效率的一种手段。为了优化多方参与的供应链分销谈判应用,本文将多边多属性谈判问题转化为多目标优化模型,采用改进的非支配遗传算法NSGA-Ⅲ计算多维空间的Pareto边界;然后,设计多线程谈判模型,将参与多方谈判的买卖各方拆解为多个双边谈判线程,分别在多维Pareto边界上进行谈判;进而,采用动态时间依赖策略(DTD),使Agent根据对方报价在Pareto边界上动态调整让步策略,快速达成协议。为验证模型的有效性,本文进行了大量模拟自动谈判实验。实验结果表明,所提出的改进算法和谈判流程优于领域最新研究成果,能有效提升多边多属性谈判效率,有助于多方达成共赢局面。

基于Pareto-GA多目标的企业管理系统优化研究——以某造纸厂为例

传统造纸厂管理优化通常只针对单一目标,忽略了质量和安全等重要方面。因此,提出了一种面向造纸厂的多个目标优化方法,并结合Pareto排序以及遗传算法搜索机制改进的Pareto-遗传算法作为求解方法,以实现对造纸厂监管系统的优化设计。研究结果显示,使用Schaffer's F6 Function进行测试时,改进的Pareto-遗传算法在72次迭代后达到最大适应度值0.93,优于其他两种算法。进一步将工期、成本、质量和安全多目标问题分解为两个子问题,成功获得3组Pareto最优解,为管理者提供不同需求下的优化方案。同时,提出的造纸厂管理系统优化设计方案能够提升造纸厂管理的效率和安全性,具有重要的理论价值和实际应用前景。

Pareto解集旋转的分类多策略预测动态多目标优化

为更有效地解决Pareto解集(Pareto set,PS)旋转的动态多目标优化问题,提出PS旋转的分类多策略预测方法(rotation-based forecasting method,RFM)。将PS的旋转类型分为PS中心点旋转、PS原点旋转和非标准旋转;针对以上不同的PS旋转类型,自适应地选择合适的预测模型,建立不同点集的时间序列,为后续进化提供初始种群。引入拉丁超立方策略(Latin hypercube strategy,LHS)生成的随机种群与上述预测种群共同构建新种群,保证种群的多样性。为验证算法的有效性,将RFM算法与DNSGA-II、PPS、SPPS和MMP算法在8个标准的动态测试函数上进行实验对比。实验结果表明,RFM算法取得了6个最优IGD值、7个最优SP值、3个最优MS值,证明了RFM算法可以更有效地解决基于PS旋转的动态多目标优化问题。同时验证了RFM算法的普适性,在FDA系列函数上进行实验对比,实验结果表明,该算法在处理非旋转的动态多目标优化问题中仍具有较优性能。

双边定时截尾下Pareto分布的参数的极大似然估计的EM算法

给出了当寿命分布为Pareto分布时,双边定时截尾寿命试验下形状参数的极大似然估计。由于似然方程形式较复杂,无法得到参数的显式表达式。但可证明此极大似然估计是唯一存在的,并利用EM算法求出了此参数的一种估计。

求解多目标流水车间调度Pareto最优解的遗传强化算法

针对多目标流水车间调度Pareto最优问题,本文建立了以最大完工时间和最大拖延时间为优化目标的多目标流水车间调度问题模型,并设计了一种基于Q-learning的遗传强化学习算法求解该问题的Pareto最优解.该算法引入状态变量和动作变量,通过Q-learning算法获得初始种群,以提高初始解质量.在算法进化过程中,利用Q表指导变异操作,扩大局部搜索范围.采用Pareto快速非支配排序以及拥挤度计算提高解的质量以及多样性,逐步获得Pareto最优解.通过与遗传算法、NSGA-II算法和Q-learning算法进行对比实验,验证了改进后的遗传强化算法在求解多目标流水车间调度问题Pareto最优解的有效性.

融合局部搜索与Pareto支配的多目标任务调度模型

为了解决复杂任务群调度过程中资源利用不均、任务完成时间较长等问题,以最小化资源负载均方差和最小化任务群完成时间为目标构建复杂任务群资源调度模型,提出一种融合局部搜索和Pareto支配的多目标优化算法BRLSN(multi-objective optimization based on boundary range local search and NSGA-Ⅱ,BRLSN)。该算法采用有效的编码方式与交叉变异算子进行迭代寻优,并利用基于边界区域局部搜索的精英保留策略扩大算法搜索范围,保存种群优良个体。实验结果表明,BRLSN相较于其他多目标算法在收敛性和多样性上有显著的提升,同时算法收敛速度更快,种群质量更高,明显优化了最终目标函数的结果值。

Multi-objective optimization of membrane structures based on Pareto Genetic Algorithm

A multi-objective optimization method based on Pareto Genetic Algorithm is presented for shape design of membrane structures from a structural view point.Several non-dimensional variables are defined as optimization variables,which are decision factors of shapes of membrane structures.Three objectives are proposed including maximization of stiffness,maximum uniformity of stress and minimum reaction under external loads.Pareto Multi-objective Genetic Algorithm is introduced to solve the Pareto solutions.Consequently,the dependence of the optimality upon the optimization variables is derived to provide guidelines on how to determine design parameters.Moreover,several examples illustrate the proposed methods and applications.The study shows that the multi-objective optimization method in this paper is feasible and efficient for membrane structures;the research on Pareto solutions can provide explicit and useful guidelines for shape design of membrane structures.

Departure Trajectory Design Based on Pareto Ant Colony Algorithm

Due to the ever-increasing air traffic flow,the influence of aircraft noise around the airport has become significant.As most airlines are trying to decrease operation cost,stringent requirements for more simple and efficient departure trajectory are on a rise.Therefore,a departure trajectory design was established for performancebased navigation technology,and a multi-objective optimization model was developed,with constraints of safety and noise influence,as well as optimization targets of efficiency and simplicity.An improved ant colony algorithm was then proposed to solve the optimization problem.Finally,an experiment was conducted using the Lanzhou terminal airspace operation data,and the results showed that the designed departure trajectory was feasible and efficient in decreasing the aircraft noise influence.

Optimal setting and placement of FACTS devices using strength Pareto multi-objective evolutionary algorithm

This work proposes a novel approach for multi-type optimal placement of flexible AC transmission system(FACTS) devices so as to optimize multi-objective voltage stability problem. The current study discusses a way for locating and setting of thyristor controlled series capacitor(TCSC) and static var compensator(SVC) using the multi-objective optimization approach named strength pareto multi-objective evolutionary algorithm(SPMOEA). Maximization of the static voltage stability margin(SVSM) and minimizations of real power losses(RPL) and load voltage deviation(LVD) are taken as the goals or three objective functions, when optimally locating multi-type FACTS devices. The performance and effectiveness of the proposed approach has been validated by the simulation results of the IEEE 30-bus and IEEE 118-bus test systems. The proposed approach is compared with non-dominated sorting particle swarm optimization(NSPSO) algorithm. This comparison confirms the usefulness of the multi-objective proposed technique that makes it promising for determination of combinatorial problems of FACTS devices location and setting in large scale power systems.

Genetic algorithm for pareto optimum-based route selection

A quality of service （QoS） or constraint-based routing selection needs to find a path subject to multiple constraints through a network. The problem of finding such a path is known as the multi-constrained path （MCP） problem, and has been proven to be NP-complete that cannot be exactly solved in a polynomial time. The NPC problem is converted into a multiobjective optimization problem with constraints to be solved with a genetic algorithm. Based on the Pareto optimum, a constrained routing computation method is proposed to generate a set of nondominated optimal routes with the genetic algorithm mechanism. The convergence and time complexity of the novel algorithm is analyzed. Experimental results show that multiobjective evolution is highly responsive and competent for the Pareto optimum-based route selection. When this method is applied to a MPLS and metropolitan-area network, it will be capable of optimizing the transmission performance.

A Modified Pareto Dominance Based Real-Coded Genetic Algorithm for Groundwater Management Model

This study proposes a groundwater management model in which the solution is performed through a combined simulation-optimization model. In the proposed model, a modular three-dimensional finite difference groundwater flow model, MODFLOW is used as simulation model. This model is then integrated with an optimization model, in which a modified Pareto dominance based Real-Coded Genetic Algorithm (mPRCGA) is adopted. The performance of the proposed mPRCGA based management model is tested on a hypothetical numerical example. The results indicate that the proposed mPRCGA based management model is an effective way to obtain good optimum management strategy and may be used to solve other type of groundwater simulation-optimization problems.

Cleaner production for continuous digester processes based on hybrid Pareto genetic algorithm

Pulping production process produces a large amount of wastewater and pollutant emitted, which has become one of the main pollution sources in pulp and paper industry. To solve this problem, it is necessary to implement cleaner production by using modeling and optimization technology. This paper studies the modeling and multi\|objective genetic algorithms for continuous digester process. First, model is established, in which environmental pollution and saving energy factors are considered. Then hybrid genetic algorithm based on Pareto stratum\|niche count is designed for finding near\|Pareto or Pareto optimal solutions in the problem and a new genetic evaluation and selection mechanism is proposed. Finally using the real data from a pulp mill shows the results of computer simulation. Through comparing with the practical curve of digester,this method can reduce the pollutant effectively and increase the profit while keeping the pulp quality unchanged.

基于Pareto支配的改进人工大猩猩部队多目标优化

针对二维和三维多目标优化的解易陷入次优和分布不规则问题,引入Pareto支配方法并提出了结合改进策略的人工大猩猩部队优化算法(MOGTO)以改善多目标优化问题。首先,利用外部档案集存储互不支配解集以防止种群经过一次寻优迭代后,删除劣解的同时错误去除非支配解。其次,加入蒙特卡洛树搜索对种群探索阶段的三种机制进行优化,增加算法全局搜索能力。同时,结合天牛须算法的左右须寻优原理及黄金正弦寻优策略对开发阶段的两种机制进行优化,生成左右须解和促进个体位置更新,引导个体扩大搜索范围以防止最优解陷入局部最优。最后,通过12个基准测试函数对所提算法进行验证并将所提算法与其他6种常见算法进行对比,实验结果表明所提算法在多目标问题的寻优能力较对比算法有较大的提升。通过曲柄摇杆机构优化设计案例测试分析,验证了所提算法在实际工程应用中的可行性和实用性。

基于多目标狼群算法的机场行李导入系统仿真优化研究

针对民航机场行李导入系统运行过程中旅客行李注入等待时间长、系统能耗高等问题,综合考虑虚拟视窗控制方式、收集带式输送机运行速度、虚拟视窗长度及同时开放值机柜台数量等关键控制参数对机场行李导入系统运行效率的影响,提出一种求解该问题的仿真优化框架。通过分析机场行李导入系统实际运行工况,建立参数化仿真优化模型。以最小化旅客行李注入平均等待时间和系统能耗为优化目标,结合系统设计和运行过程中的实际约束条件,建立该问题的数学模型,并设计了一种多目标自适应并行狼群算法进行求解。该算法针对所提问题特性及经典狼群算法易陷入局部最优和收敛速度慢等不足,提出一种混合整实数单链编码方式,融合反向学习策略生成初始种群,引入自适应游走概率机制和智能行为并行机制,采用局部和全局自适应邻域搜索及启发式保优策略实现狼群算法智能行为搜索,使用Pareto非支配排序进行寻优迭代并获得最优解集。以国内某大型国际航空枢纽机场行李导入系统为例设计不同规模多种算法对比实验,验证了所提方法的有效性和优越性。

基于多目标优化的变电站消防资源配置算法

针对变电站消防资源分配与分布不均匀的问题,提出了一种基于多目标优化的变电站消防资源配置算法。该算法采用电力生产场所的道路网作为变电站消防责任区划分的依据,并结合各划分区域的消防需求构建消防资源配置模型。根据该模型的特点,在帕累托最优解的约束下提出了一种基于模拟退火的多目标优化算法,来求解该消防资源配置模型。仿真与实验结果表明,所提出的消防资源配置模型更符合实际变电站各场所分布的特点,且所提出的多目标优化算法得到的消防资源分配结果能在消防资源有限的条件下,实现最大的配置效益和快速的消防响应。

配电网多目标优化重构模型及多目标烟花求解算法研究

针对配电网优化重构问题,以最小化有功网损、最小化电压偏移度以及最小化负荷平衡度作为目标函数建立配电网多目标优化重构模型。提出一种多策略混合的改进烟花算法(Improved fireworks algorithm,IMFWA)进行求解。算法采用不重复环路编码,压缩解空间,提高搜索效率;采用Sobol序列生成初始种群,增强种群的多样性和遍历性;利用优化烟花和随机烟花进行位移操作,保持种群多样性;采用高斯与柯西的混合变异方式,提高寻优效率;利用Pareto支配关系以及适应度与拥挤度函数组成的综合指标对最优解集进行排列选取,提高收敛速度。对IEEE-33节点系统进行仿真试验,验证了所提出的方法是有效和可行的,试验结果表明优化重构方案能够有效改善配电网的运行指标,并根据不同实际情况为电网人员提供重构方案。

考虑风电条件风险的水火风联合调度模型及求解

在“双碳”战略和高比例可再生能源并网政策背景下,为准确量化风电等新能源消纳成本及其随机性造成的风险损失以支持电力调度决策,采用CVaR建模风电随机性造成的弃风和弃负荷条件风险值,并应用Copula函数计算连续马尔可夫链风速模型预测风电出力,建立风电不确定风险损失、发电成本和污染排放最小的水火风电短期多目标调度模型。并通过可变外部种群规模、增强局部搜索能力和基于K近邻距离的精英种群淘汰规则3方面改进SPEA2算法以对该模型进行高效求解。仿真结果显示CVaR能很好建模风电不确定风险,并通过改进SPEA2找到更好的Pareto最优解集。

针对不规则Pareto前沿的高维多目标优化算法应用

不规则的Pareto前沿面问题,具有不连续、退化的、倒置等不规则形式,利用传统的优化算法往往不能达到最优值.针对此问题,通过改进RVEA算法,使用参考向量再生的方式丰富解集以充分遍历不规则Pareto前沿面,提出Dynamic-RVEA算法.该方法利用随机函数随机在目标向量的取值范围内生成新的参考向量来替换原来的单位参考向量,然后通过在DTLZ测试问题集上超体积指标(HV)实验结果性能对比.实验结果表明Dynamic-RVEA在超体积指标HV性能指标上表现突出.