A bi-population based estimation of distribution algorithm for the flexible job-shop scheduling problem

In this paper, an effective bi-population based estimation of distribution algorithm (BEDA) is proposed to solve the flexible job-shop scheduling problem (FJSP) with the criterion to minimize the maximum completion time (makespan). The BEDA stresses the balance between global exploration and local exploitation. In the framework of estimation of distribution algorithm, two sub-populations are used to adjust the machine assignment and operation sequence respectively with a splitting criterion and a combination criterion. At the initialization stage, multiple strategies are utilized in a combination way to generate the initial solutions. At the global exploration phase, a probability model is built with the superior population to generate the new individuals and a mechanism is proposed to update the probability model. At the local exploitation phase, different operators are well designed for the two sub-populations to generate neighbor individuals and a local search strategy based on critical path is proposed to enhance the exploitation ability. In addition, the influence of parameters is investigated based on Taguchi method of design of experiment, and a suitable parameter setting is determined. Finally, numerical simulation based on some widely used benchmark instances is carried out. The comparisons between BEDA and some existing algorithms as well as the single-population based EDA demonstrate the effectiveness of the proposed BEDA in solving the FJSP.     

柔性作业车间调度中的组合遗传优化研究

针对柔性作业车间调度问题,提出一种组合遗传算法。该算法在种群初始化、选择、交叉、变异各阶段,组合使用各种不同的策略。针对机器编码部分的交叉,提出一种基于工件的机器交叉算子,用以改进机器分配部分随机交叉引起的对父代优秀基因继承不足的缺陷。通过对典型算例的计算以及与其他文献的研究成果比较,证明该算法的优良性能。     

免疫克隆选择算法求解柔性生产调度问题

为减少计算复杂度,将具有解决复杂组合优化问题的免疫克隆选择算法应用于求解柔性生产调度问题.首先设计一种有效的抗原和抗体的数据结构,用抗原表示待调度的生产计划,抗体表示高效的柔性生产调度结果;然后着重设计了用于产生高效的柔性生产调度结果的克隆免疫算子;最后运用该模型对一个实际生产系统进行仿真调度决策,实验评估结果验证了算法的正确性和有效性.     

改进蝙蝠算法柔性作业车间调度问题研究

针对柔性作业车间调度问题,提出了一种改进的离散蝙蝠算法。该算法采用双层编码序列方式,利用均衡机器负载分配策略和插入式解码方案初始化种群,同时设计了离散蝙蝠算法的速度、位置更新的相关算子和操作,引入了平衡调整因子改善算法搜索能力。通过案例测试并与其他算法比较,验证了改进的离散蝙蝠算法可以有效地求解柔性作业车间调度问题,并具有较高的精确度。     

重启进化提高较大搜索规模时柔性作业解质量

种群多样性下降导致的早熟收敛限制了进化算法的求解质量与搜索效率。为应对收敛,提高较大搜索规模时的求解质量,引入随机算法中重启策略。种群收敛时,利用算法前期搜索结果（优势元素）和新产生的随机元素重新构造新种群继续进化。提高柔性作业车间调度问题解质量对实际工业生产有重要的现实意义。将重构思想应用于协同进化算法求解复杂柔性作业调度问题并跟踪种群进化状态。仿真实验结果表明,改进算法在进化过程中维持了较好的种群多样性,大幅提高了算法求解复杂柔性作业调度的搜索性能,并可以简单通过扩大搜索规模提高作业调度解质量。     

求解作业车间调度问题的禁忌分布估计算法

为优化作业车间调度问题的解,提出一个禁忌和分布估计的混合算法。分布估计算法是一种新的进化模式,通过概率优化模型在连续空间进行求解;通过对已获得的群体进行选择操作生成优势群体,提出的分布估计算法使用单变量边缘分布算法构建概率模型,估计离散空间中的联合概率分布,从概率向量采样生成新群体;采用基于工件编号的编码和解码机制保证解的可行性。为提高局部搜索能力,算法基于禁忌搜索算法设计新的双重移动组合、块禁忌和选择策略,在搜索陷入局部最优时利用遗传算法的变异算子生成新解;算法通过混合分布估计算法和禁忌搜索算法的优点,兼具全局搜索与局部搜索能力,提高了搜索的效率和性能。通过与现有算法在典型实例上的实验结果比较,表明该算法在求解作业车间调度问题上具有可行性和有效性。     

超启发式交叉熵算法求解分布式装配柔性作业车间调度问题

本文针对一类新型两阶段分布式装配柔性作业车间调度问题(DAFJSP),建立问题模型,以最小化最大完工时间为优化目标并提出一种超启发式交叉熵算法(HHCEA)进行求解.首先,设计基于工序序列、工厂分配和产品序列的三维向量编码规则和结合贪婪策略的解码规则,同时提出4种启发式方法以提高初始解的质量.然后,设计高低分层结构的HHCEA,高层为提高对搜索方向的引导性,采用交叉熵算法(CEA)学习和积累优质排列的信息,其中各排列由结合问题特点设计的11种启发式操作(即11种有效的邻域操作)构成;低层为增加在解空间中的搜索深度,将高层确定的每个排列中的启发式操作依次重复执行指定次数并在执行过程中加入基于模拟退火的扰动机制,以此作为一种新的启发式方法执行搜索.最后,通过仿真实验与算法对比验证HHCEA可有效求解DAFJSP.     

混合粒子群算法在模糊柔性车间作业计划中的应用*

针对现实生产系统中存在的时间参数模糊化问题,给出了一种基于区间值梯形模糊数的模糊柔性车间作业计划问题模型。在对模糊柔性车间作业计划问题进行有效求解方面,针对基本粒子群算法容易陷入局部最优的问题,随后给出了一种基于遗传操作的混合粒子群算法,利用遗传算法思想对粒子进行交叉、变异操作,增强了算法跳出局部最优的能力。仿真实验表明,该算法具有可行性和有效性。     

改进生物地理学算法求解柔性作业调度问题

针对柔性作业车间调度问题的特点,提出了一种基于改进生物地理学优化算法的求解方案。该方案采用基于工序和基于机器相结合的编码机制,在初始种群中引入启发式算法生成的优良个体,并在标准生物地理学算法基础上对迁移和变异操作进行了改进,采用符合该调度问题的迁移率模型和自适应变异机制,克服了传统算法易于早熟或收敛慢的缺点。通过仿真验证了该算法的可行性和有效性。     

An effective hybrid particle swarm optimization algorithm for multi-objective flexible job-shop scheduling problem

Flexible job-shop scheduling problem (FJSP) is an extension of the classical job-shop scheduling problem. Although the traditional optimization algorithms could obtain preferable results in solving the mono-objective FJSP. However, they are very difficult to solve multi-objective FJSP very well. In this paper, a particle swarm optimization (PSO) algorithm and a tabu search (TS) algorithm are combined to solve the multi-objective FJSP with several conflicting and incommensurable objectives. PSO which integrates local search and global search scheme possesses high search efficiency. And, TS is a meta-heuristic which is designed for finding a near optimal solution of combinatorial optimization problems. Through reasonably hybridizing the two optimization algorithms, an effective hybrid approach for the multi-objective FJSP has been proposed. The computational results have proved that the proposed hybrid algorithm is an efficient and effective approach to solve the multi-objective FJSP, especially for the problems on a large scale.     

Greedy randomized adaptive search for dynamic flexible job-shop scheduling

Dynamic flexible job shop scheduling problem is studied under the events such as new order arrivals, changes in due dates, machine breakdowns, order cancellations, and appearance of urgent orders. This paper presents a constructive algorithm which can solve FJSP and DFJSP with machine capacity constraints and sequence-dependent setup times, and employs greedy randomized adaptive search procedure (GRASP). Besides, Order Review Release (ORR) mechanism and order acceptance/rejection decisions are also incorporated into the proposed method in order to adjust capacity execution considering customer due date requirements. The lexicographic method is utilized to assess the objectives: schedule instability, makespan, mean tardiness and mean flow time. A group of experiments is also carried out in order to verify the suitability of the GRASP in solving the flexible job shop scheduling problem. Benchmark problems are formed for different problem scales with dynamic events. The event-driven rescheduling strategy is also compared with periodical rescheduling strategy. Results of the extensive computational experiment presents that proposed approach is very effective and can provide reasonable schedules under event-driven and periodic scheduling scenarios.     

求解柔性作业车间调度问题的鸟群算法

柔性作业车间调度问题是生产调度领域中非常重要的一类带约束优化问题。根据其求解特性,提出一种基于改进的鸟群算法求解以最小化最大完工时间为目标的柔性作业车间调度问题的方法。该方法采用随机黑洞策略改进鸟群的觅食方式,自适应的动态调整策略改善鸟群的迁移步长,从而提高种群的多样性并加速算法的收敛速度;通过对关键路径上工序的领域搜索加强算法的局部搜索能力。最后利用实际制造企业的生产加工数据以及标准测试实例进行仿真实验,实验结果表明,该算法在问题的求解精度和收敛速度上具有一定的优势,是一种有效的求解柔性作业车间调度问题的新方法。     

多目标柔性作业车间调度问题的混合差分算法

多目标柔性作业车间调度问题属于NP-hard问题。在对该问题进行分析的基础上,为之建立了数学模型,并改进了多目标函数,使其更符合实际需要。提出了一种求解该问题的混合差分演化算法,该算法针对差分演化算法易陷入局部最优现象,提出了算法早熟收敛判定方法,并且利用混沌搜索解决早熟收敛问题,突破了局部极值的限制以再次寻优计算。仿真结果表明,该算法效率高,寻优速度快,有效地解决了收敛性能和早熟之间的矛盾。     

基于DEA混合算法的模糊车间作业计划问题的研究*

针对以最小化制造跨度为目标,具有模糊加工时间的车间作业计划问题,采用梯形模糊数来表征时间参数,并应用可能性理论,在此基础上构建车间作业计划问题目标函数。为了对模糊环境下的车间作业计划问题进行有效求解,给出了一种DEA-GA混合求解算法,混合算法采用了DNA进化算法的分裂、变异和水平选择算子,然后利用遗传算法的交叉算子实现个体之间的交互,避免早熟收敛。仿真实验表明,该算法高效可行,与GA等优化算法相比,具有更快的收敛速度。     

An effective heuristic for flexible job-shop scheduling problem with maintenance activities

Most production scheduling problems, including the standard flexible job-shop scheduling problem (FJSP), assume that machines are continuously available. However, in most realistic situations, machines may become unavailable during certain periods due to preventive maintenance (PM). In this paper, a flexible job-shop scheduling problem with machine availability constraints is considered. Each machine is subject to preventive maintenance during the planning period and the starting times of maintenance activities are either flexible in a time window or fixed beforehand. Moreover, two cases of maintenance resource constraint are considered: sufficient maintenance resource available or only one maintenance resource available. To deal with this variant FJSP problem with maintenance activities, a filtered beam search (FBS) based heuristic algorithm is proposed. With a modified branching scheme, the machine availability constraint and maintenance resource constraint can be easily incorporated into the proposed algorithm. Simulation experiments are conducted on some representative problems. The results demonstrate that the proposed filtered beam search based heuristic algorithm is a viable and effective approach for the FJSP with maintenance activities.     

生物地理学算法求解柔性车间作业调度问题

针对加工设备和操作工人双资源约束的柔性作业车间调度问题,建立以生产时间和生产成本为目标函数的柔性作业车间调度模型,提出基于模糊Pareto支配的生物地理学算法,采用模糊Pareto支配的方法计算解之间的支配关系并对Pareto解集排序,进行全局最优值的更新,并采用余弦迁移模型来改善生物地理学算法的收敛速度。将该方法应用于某模具车间的柔性作业车间调度中,仿真结果验证了该方法的可行性和有效性。     

Bi-criteria flexible job-shop scheduling with sequence-dependent setup times—Variable neighborhood search approach

In scheduling problems, taking the sequence-dependent setup times into account is one of the important issues that have recently been considered by researchers in the production scheduling field. In this paper, we consider flexible job-shop scheduling problem (FJSP) with sequence-dependent setup times to minimize makespan and mean tardiness. The FJSP consists of two sub-problems from which the first one is to assign each operation to a machine out of a set of capable machines, and the second one deals with sequencing the assigned operations on all machines. To solve this problem, a variable neighborhood search (VNS) algorithm based on integrated approach is proposed. In the presented optimization method, the external loop controlled the stop condition of algorithm and the internal loop executed the search process. To search the solution space, the internal loop used two main search engines, i.e. shake and local search procedures. In addition, neighborhood structures related to the sequencing problem and the assignment problem were employed to generate neighboring solutions. To evaluate the performance of the proposed algorithm, 20 test problems in different sizes are randomly generated. Consequently, computational results and comparisons validate the quality of the proposed approach.     

烟花算法求解JSP问题的研究

烟花算法是一种新型智能优化算法,该算法模拟烟花在空中爆炸产生火花这一过程。烟花算法的求解过程包含两种机制：产生爆炸火花,从而实现算法的局部和全局寻优过程;产生高斯变异火花,从而增加种群的多样性以便将优良个体遗传到下一代。通过设计四个参数实验,分析了主要参数对算法求解能力的影响,找出求解作业车间调度问题的较优参数。最后通过对作业车间调度的标准问题进行仿真对比实验,证明了烟花算法求解作业车间调度问题的有效性和稳定性。     

改进人工蜂群算法求解模糊柔性作业车间调度问题

模糊柔性作业车间调度问题(FFJSP)是柔性作业车间调度问题(FJSP)的拓展,具有很强的现实意义.针对FFJSP,本文提出了一种基于领域搜索的改进人工蜂群算法.该算法以最小化最大模糊完工时间为目标.首先,为了提高初始种群的多样性,引入混沌理论来初始化种群.其次,为了提高算法的局部搜索能力,采用4种邻域结构对蜜源进行邻域搜索.为了进一步优化蜜源和加快种群的收敛速度,采用了一种新颖的交叉操作.并且在解码的过程中采用左移策略,从而很好地利用机器的空闲时间.最后,选取了3组通用数据集来测试算法的性能,并与代表性算法进行比较.结果表明,对于大部分实例,本文所提出的的算法的结果要优于与之对比的算法.     

Mathematical modeling and a hybridized bacterial foraging optimization algorithm for the flexible job-shop scheduling problem with sequencing flexibility

The flexible job-shop scheduling problem (FJSP) is an extension of the classical job-shop scheduling problem (JSP) in which operations can be performed by a set of candidate capable machines. An extended version of the FJSP, entitled sequencing flexibility, is studied in this work, which considers precedence between the operations in the form of a directed acyclic graph instead of a sequential order. In this work, a mixed integer linear programming (MILP) formulation is presented to minimize weighted tardiness for the FJSP with sequencing flexibility. Due to the NP-hardness of the problem, a novel biomimicry hybrid bacterial foraging optimization algorithm (HBFOA) is developed, which is inspired by the behavior of E. coli bacteria in its search for food. The developed HBFOA search method is hybridized with simulated annealing (SA). Additionally, the algorithm has been enhanced by a local search method based on the manipulation of critical operations. Classical dispatching rules have been employed to create the initial swarm of HBFOA, and a new dispatching rule named minimum number of operations has been devised. The developed approach has been packaged in the form of a decision support system (DSS) developed on top of Microsoft Excel—a tool most small and mid-range enterprises (SME) use heavily for planning. A case study with local industry is presented to validate the proposed HBFOA and MILP. Additional numerical experiments using literature benchmarks are further used for validation. The results demonstrate that the HBFOA outperformed the classical dispatching rules and the best integer solution of MILP when minimizing the weighted tardiness and offered comparable results for the makespan instances.