基于Wang-Landau算法的动态设施布局方法

动态设施布局问题是设施在车间内多个阶段的布局规划问题。目前,针对动态设施布局问题,国内外学者对离散模型研究较多,而对连续模型的研究却较少。根据连续动态设施布局的特性与需求,构建了不等面积设施的动态设施布局连续模型。求解该模型的难点在于缺乏一种高效的布局优化方法。Wang-Landau算法是一种改进的蒙特卡罗算法。通过将Wang-Landau算法与空位点放置策略、外推移动策略、内压移动策略三种启发式策略相结合,提出一种基于Wang-Landau抽样的启发式算法,并以此求解该模型。使用文献中已有的测试算例对提出的算法进行测试,计算结果表明,所提出的算法在求解连续动态设施布局问题上是有效的。     

变邻域遗传算法在车间物流调度中的应用

针对含有自动引导小车(Automated Guided Vehicle,AGV)的离散化车间物流调度问题,以最小化物流任务时间惩罚成本和最小化运载小车的总行驶距离为优化目标,构建离散化车间多目标物流调度优化模型,设计一种基于Pareto寻优的多目标混合变邻域搜索遗传算法(VNSGA-II).以遗传算法为基础,通过使用NSGA-II的Pareto分层和拥挤度计算方法评估种群优劣实现多目标优化,为了提高算法的寻优能力,避免算法陷入局部最优,通过添加保优记忆库对精英个体进行保护,并利用变邻域搜索算法在搜索过程中的局部寻优能力,针对本文模型特点,设计6个随机邻域结构,来达到算法求解最优值的目标.并提出了基于关键AGV小车的插入邻域和基于关键物流任务的交换邻域调整策略以进一步降低成本.最后,以某离散车间物流调度为实例,分别使用VNSGA-II、带精英策略的快速非支配排序遗传算法Ⅱ(Nondominated Sorting Genetic AlgorithmⅡ,NSGA-II)和强Pareto进化算法(Strong Pareto Evolutionary Algorithm 2,SPEA2)对问题进行求解,计算结果表明,VNSGA-II能得到更好的Pareto解集,验证了算法的有效性和可行性.     

改进柔性隔间结构的不等形面积设施布局研究

不等形面积设施布局（UA-FLP）是一类广义的设施布局问题,允许所布置的设施在面积确定情况下通过改变其长宽而具有不同的形状。由于不等形面积设施布局额外增加了设施形状的变化维度,因此在求解过程中需要针对设施形状设定生成规则。在原来柔性隔间结构的基础上增加了隔间的方向性,所提出的改进柔性隔间结构在保证简洁性的同时扩大了整体的寻优空间。结合具有针对性的再搜索策略设计了求解问题的模拟退火算法,通过与采用柔性隔间结构表示的多个算例进行计算比较,验证了改进隔间结构的有效性与通用性。     

混合粒子群算法求解多目标柔性作业车间调度问题

柔性作业车间调度问题是生产管理领域和组合优化领域的重要分支.本文提出一种基于Pareto支配的混合粒子群优化算法求解多目标柔性作业车间调度问题.首先采用基于工序排序和机器分配的粒子表达方式,并直接在离散域进行位置更新.其次,提出基于BaldWinian学习策略和模拟退火技术相结合的多目标局部搜索策略,以平衡算法的全局探索能力和局部开发能力.然后引入Pareto支配的概念来比较粒子的优劣性,并采用外部档案保存进化过程中的非支配解.最后用于求解该类问题的经典算例,并与已有算法进行比较,所提算法在收敛性和分布均匀性方面均具有明显优势.     

求解多目标问题的Memetic免疫优化算法

将基于Pareto支配关系的局部下山算子和差分算子引入免疫多目标优化算法之中,提出了一种求解多目标问题的Memetic免疫优化算法(Memetic immune algorithm for multiobjective optimization,简称MIAMO).该算法利用种群中抗体在决策空间上的位置关系设计了两种有效的启发式局部搜索策略,提高了免疫多目标优化算法的求解效率.仿真实验结果表明,MIAMO与其他4种有效的多目标优化算法相比,不仅在求得Pareto最优解集的逼近性、均匀性和宽广性上有明显优势,而且算法的收敛速度与免疫多目标优化算法相比明显加快.     

改进人工蜂群求解多目标柔性作业车间调度问题

针对多个目标约束的柔性作业车间问题,本文采用基于Pareto解集的改进离散人工蜂群算法来求解.由于经典人工蜂群算法的选择概率不适用于多目标问题,本文对选择概率进行了重定义,将排序引入选择概率中;同时采用基于变异操作的邻域搜索方法进行局部搜索,并使用混合列交叉算子提高种群的多样性;采用Harmonic平均距离对Pareto解集进行裁剪,完成对Pareto解集的更新.最后通过实例测试及仿真实验,验证了本文算法在求解多目标柔性作业车间调度时的有效性.     

多蚁群分级优化的多目标求解方法*

为提高多目标优化方法的求解性能,在给出了蚁群算法优化函数类问题求解方法的基础上,提出了基于多蚁群分级优化多目标问题的求解方法。构建了子蚁群以自身启发式信息及以其他子群的启发式信息获得准Pareto解以及采用各子群的每一只蚂蚁获得的准Pareto解作支配判断,从而提高Pareto解的多样性;构建了父蚁群以准Pareto解作为空间节点构成TSP类似的组合优化问题,其求解结果以获得多目标优化问题的Pareto解的前沿,从而提高Pareto解的均匀分布性。通过优化实例验证,结果表明,多蚁群分级优化的多目标求解方法     

求解多目标作业车间调度问题的混合变异杂草优化算法

针对多目标作业车间调度问题,提出一种混合变异杂草优化算法。该算法采用基于各子目标熵值权重的欧氏贴近度作为适应度值计算方法,引导种群向Pareto前端进化。在进化过程中,运用快速非支配排序策略构建Pareto档案,并利用进化种群中最优个体实时更新Pareto最优解集,提升算法的优化性能;同时通过引入变异算子增加种群多样性,避免算法陷入局部最优。最后,基于Benchmark算例的仿真实验,验证了该算法求解多目标作业车间调度问题的有效性。     

改进的蚁群算法求解多目标车间作业调度问题

目前已经有许多解决作业车间调度问题的启发式求解方法,但这些方法多数局限于单目标,因此不能满足现实生活中多目标作业车间调度问题的应用需求。提出一种改进的蚁群算法启发式地搜索多目标车间作业调度问题的近似最优解以满足实际的应用需求。通过对转移概率以及信息素更新方式进行改进,并融合交叉策略,确保算法在加快搜索收敛速度的同时又避免陷入局部最优。仿真实验证明,改进的算法具有较好的性能,能够解决实际生活中的多目标作业车间调度问题。     

多目标混合遗传算法求解流水车间调度问题

为高效地求解多目标流水车间调度问题,提出了一种多目标混合遗传算法,此算法将局部搜索融入进化计算中,采用非劣解并行局部搜索策略,并依据基于Pareto支配关系的个体排序数和密度值进行适应度赋值,以加速算法的收敛,保持群体多样性.仿真结果表明,新算法能够有效地解决多目标流水车间调度问题.     

Applying multi-objective ant colony optimization algorithm for solving the unequal area facility layout problems

The unequal area facility layout problem (UA-FLP) which deals with the layout of departments in a facility comprises of a class of extremely difficult and widely applicable multi-objective optimization problems with constraints arising in diverse areas and meeting the requirements for real-world applications. Based on the heuristic strategy, the problem is first converted into an unconstrained optimization problem. Then, we use a modified version of the multi-objective ant colony optimization (MOACO) algorithm which is a heuristic global optimization algorithm and has shown promising performances in solving many optimization problems to solve the multi-objective UA-FLP. In the modified MOACO algorithm, the ACO with heuristic layout updating strategy which is proposed to update the layouts and add the diversity of solutions is a discrete ACO algorithm, with a difference from general ACO algorithms for discrete domains which perform an incremental construction of solutions but the ACO in this paper does not. We propose a novel pheromone update method and combine the Pareto optimization based on the local pheromone communication and the global search based on the niche technology to obtain Pareto-optimal solutions of the problem. In addition, the combination of the local search based on the adaptive gradient method and the heuristic department deformation strategy is applied to deal with the non-overlapping constraint between departments so as to obtain feasible solutions. Ten benchmark instances from the literature are tested. The experimental results show that the proposed MOACO algorithm is an effective method for solving the UA-FLP.     

Multi-objective layout optimization of a satellite module using the Wang-Landau sampling method with local search

The layout design of satellite modules is considered to be NP-hard. It is not only a complex coupled system design problem but also a special multi-objective optimization problem. The greatest challenge in solving this problem is that the function to be optimized is characterized by a multitude of local minima separated by high-energy barriers. The Wang-Landau (WL) sampling method, which is an improved Monte Carlo method, has been successfully applied to solve many optimization problems. In this paper we use the WL sampling method to optimize the layout of a satellite module. To accelerate the search for a global optimal layout, local search (LS) based on the gradient method is executed once the Monte-Carlo sweep produces a new layout. By combining the WL sampling algorithm, the LS method, and heuristic layout update strategies, a hybrid method called WL-LS is proposed to obtain a final layout scheme. Furthermore, to improve significantly the efficiency of the algorithm, we propose an accurate and fast computational method for the overlapping depth between two objects (such as two rectangular objects, two circular objects, or a rectangular object and a circular object) embedding each other. The rectangular objects are placed orthogonally. We test two instances using first 51 and then 53 objects. For both instances, the proposed WL-LS algorithm outperforms methods in the literature. Numerical results show that the WL-LS algorithm is an effective method for layout optimization of satellite modules.     

基于NSGA Ⅱ的多目标车间设施布局优化方法

针对多品种批量生产系统,提出了一种基于NSGAII的多目标车间设施布局优化方法。以物料搬运量(或搬运成本)、非物流关系强度、设施所需总面积为优化目标建立了一类多目标优化模型;针对模型设计了一种改进的非支配排序多目标遗传算法;通过案例分析验证了该方法的有效性。     

带静不平衡约束的正交矩形布局问题的启发式模拟退火算法*

以卫星舱布局为背景,研究一类带静不平衡约束的正交矩形布局问题.借鉴拟物策略,定义矩形与矩形、矩形与圆形容器之间的嵌入度计算公式,将该问题转变为无约束的优化问题.通过将启发式格局更新策略、基于梯度法的局部搜索机制与具有全局优化功能的模拟退火算法相结合,提出一种求解带静不平衡约束的正交矩形布局问题的启发式模拟退火算法.算法中的启发式格局更新策略产生新格局和跳坑,梯度法搜索新格局附近能量更低的格局.另外,在布局优化过程中,通过在挤压弹性势能的基础上增加静不平衡量惩罚项,并采用质心平移的方法,使布局系统的静不平衡量达到约束要求.实验表明,文中算法是一种解决带静不平衡约束的正交矩形布局问题的有效算法.     

网络社区发现的多目标分解粒子群优化算法

通过分析社会网络中社区发现问题的优化目标,构造了社区发现的多目标优化模型,提出一种网络社区发现的多目标分解粒子群优化算法。该算法采用切比雪夫法将多目标优化问题分解为多个单目标优化子问题,使用粒子群优化(PSO)算法对社区结构进行挖掘,并引入了一种新颖的基于局部搜索的变异策略以提高算法的搜索效率和收敛速度,该算法克服了单目标优化算法存在的解单一以及难以发现社区层次结构的缺陷。人工网络及真实网络上的实验结果表明,该算法能够快速准确地挖掘网络社区并揭示社区的层次结构。     

A new heuristic algorithm for the circular packing problem with equilibrium constraints

The circular packing problem with equilibrium constraints is an optimization problem about simplified satellite module layout design.A heuristic algorithm based on tabu search is put forward for solving this problem.The algorithm begins from a random initial configuration and applies the gradient method with an adaptive step length to search for the minimum energy configuration.To jump out of the local minima and avoid the search doing repeated work,the algorithm adopts the strategy of tabu search.In the pr...     

基于禁忌搜索的启发式算法求解带平衡约束的圆形装填问题

带平衡约束的圆形装填(Packing)问题是一类简化的卫星舱布局优化问题.现提出一个基于禁忌搜索的启发式(TSH)算法对该问题进行求解.算法从任一初始格局出发,应用基于自适应步长的梯度法进行能量极小化.为了使计算能有效地逃离局部极小点的陷阱且避免迂回搜索,算法采用了禁忌搜索的策略.在禁忌搜索的过程中,我们对传统的邻域解、禁忌对象以及当前解接受原则进行了有效的改进.对两组共11个有代表性的算例进行了实算.计算结果表明,TSH算法刷新了其中7个算例的当今国际上的最好纪录,对于其余4个算例,该算法均达到问题的最优解.     

Facility layout by collision detection and force exertion heuristics

Facility layout problem (FLP) considers the optimization of layout costs, primarily on the account of material handling costs. FLP can be solved via mathematical modelling, heuristic or metaheuristic approaches. This paper presents a novel heuristic approach for solving the unequal area FLP. Here, facilities are randomly generated points that exert forces on each other based on a relation matrix. In this setup, every point is a centroid of the respective facility shape and two heuristic methods are used to detect and consequently remove the collisions where the heuristic parameters influence the speed and quality of the final results. Furthermore, a graphic user interface (GUI) is designed to monitor performance of the proposed heuristic algorithm and modify its parameters while running if required. Finally, layout in higher dimensional space, facility rotation and future possible extensions are discussed.