A swarm optimization approach for flexible flow shop scheduling with multiprocessor tasks

In simple flow shop problems, each machine operation center includes just one machine. If at least one machine center includes more than one machine, the scheduling problem becomes a flexible flow shop problem (FFSP). Flexible flow shops are thus generalization of simple flow shops. Flexible flow shop scheduling problems have a special structure combining some elements of both the flow shop and the parallel machine scheduling problems. FFSP can be stated as finding a schedule for a general task graph to execute on a multiprocessor system so that the schedule length can be minimized. FFSP is known to be NP-hard. In this study, we present a particle swarm optimization (PSO) algorithm to solve FFSP. PSO is an effective algorithm which gives quality solutions in a reasonable computational time and consists of less numbers parameters as compared to the other evolutionary metaheuristics. Mutation, a commonly used operator in genetic algorithm, has been introduced in PSO so that trapping of solutions at local minima or premature convergence can be avoided. Logistic mapping is used to generate chaotic numbers in this paper. Use of chaotic numbers makes the algorithm converge fast towards near-optimal solution and hence reduce computational efforts further. The performance of schedules is evaluated in terms of total completion time or makespan (C_max). The results are presented in terms of percentage deviation (PD) of the solution from the lower bound. The results are compared with different versions of genetic algorithm (GA) used for the purpose from open literature. The results indicate that the proposed PSO algorithm is quite effective in reducing makespan because average PD is observed as 2.961, whereas GA results in average percentage deviation of 3.559. Finally, influence of various PSO parameters on solution quality has been investigated.     

A particle swarm optimization for multi-objective flowshop scheduling

The academic approach of single-objective flowshop scheduling has been extended to multiple objectives to meet the requirements of realistic manufacturing systems. Many algorithms have been developed to search for optimal or near-optimal solutions due to the computational cost of determining exact solutions. This paper provides a particle swarm optimization-based multi-objective algorithm for flowshop scheduling. The proposed evolutionary algorithm searches the Pareto optimal solution for objectives by considering the makespan, mean flow time, and machine idle time. The algorithm was tested on benchmark problems to evaluate its performance. The results show that the modified particle swarm optimization algorithm performed better in terms of searching quality and efficiency than other traditional heuristics.     

面向多目标优化的云制造虚拟资源调度方法

为解决传统资源调度方法使云制造的资源分配过程响应速度低、分配不均衡的问题,提出一种以提高制造效率、维持资源负载均衡为目标的多目标优化模型,并设计了一种改进型粒子群算法避免其陷入局部最优解,以实现复杂制造过程所需资源的合理分配。以钢铁烧结制造过程的云制造仿真为例,对模型及算法进行了仿真分析,验证了其有效性。     

多目标柔性作业车间调度优化研究

提出了一种集成权重系数变化法和小生境技术的混合遗传算法,建立了包括时间、成本、交货期满意度和设备利用率在内的多目标优化模型。采用基于工序的编码方式和“间隙挤压法”活动化解码方法;遗传算子包括选择、交叉、变异3种类型;选择操作采用轮盘赌选择方式。为了保证解的收敛性和多样性,采用了精英保留策略和小生境技术。交叉操作采用线性次序交叉方式;变异操作采用互换操作变异方法。染色体的适应度是各个目标函数的随机加权和。仿真实验证明,提出的混合遗传算法可以有效解决柔性作业车间多目标调度优化问题。     

多目标离散灰狼优化算法求解作业车间节能调度问题

针对作业车间节能调度问题,建立了一种以优化总能耗和工件最大完工时间为目标的节能调度模型,并提出一种多目标离散灰狼优化算法进行求解.根据问题的特点,首先采用离散整数编码方式,利用调度规则生成初始种群;其次引入一种基于跟踪模式和搜寻模式的双模式并行搜索方法,并在搜索过程中动态调整两种模式下个体的数目,以协调算法全局和局部搜...     

制造过程多目标优化的集成计算智能方法

针对制造过程因动态多变而难以定量控制的问题,提出了用集成计算智能方法进行多目标优化。利用人工神经网络进行系统建模,并为遗传算法找到适应度函数及求得目标函数值的方法,进而利用遗传算法进行多目标优化。通过实例验证了方法的有效性与实用性,实现了制造过程的定量分析,为复杂制造系统的建模和优化提出了一种新的方法。     

带多处理器任务的动态混合流水车间调度问题

研究了具有多处理器任务的混合流水车间调度问题,且考虑相邻两阶段之间的运输时间、机器故障和工件动态到达的实际生产特征。由于该问题不但求解非常复杂,对它的不同部分的简化还会使其变成其他不同的典型调度问题,探讨该类问题的近似解法具有挑战性和广义性。据此分别采用结合次梯度算法的拉格朗日松弛算法、结合次梯度和bundle算法的交替算法（交替S＆B算法）的拉格朗日松驰算法进行求解。对多达100个工件的问题进行测试,结果表明,所设计的算法能够在合理的CPU时间内产生较好的时间表。     

Solving a new fuzzy multi-objective model for a multi-skilled manpower scheduling problem by particle swarm optimization and elite tabu search

Manpower scheduling is a complicated problem to solve that strives to satisfy employers’ objectives and employees’ preferences as much as possible by generating fairly desirable schedules. But sometimes, objectives and preferences may not be determined precisely. This problem causes manpower scheduling takes the fuzzy nature. This paper presents a new fuzzy multi-objective mathematical model for a multi-skilled manpower scheduling problem considering imprecise target values of employers’ objectives and employees’ preferences. Hence, a fuzzy goal programming model is developed for the presented mathematical model and two fuzzy solution approaches are used to convert the fuzzy goal programming model to two single-objective models. Since the complexity of a manpower scheduling problem is NP-hard, the single-objective models are solved by two meta-heuristics, namely particle swarm optimization and elite tabu search. Eventually, the performance of the proposed algorithms is verified and the results are compared with each other to select the best schedules.     

车间多目标优化调度问题的研究方法和应用

系统地总结近年来车间多目标调度问题中常用的研究方法,介绍算法的基本思想和实际的使用情况,总结车间调度问题研究中的不足和局限性.     

Hybrid discrete particle swarm optimization for multi-objective flexible job-shop scheduling problem

Flexible job-shop problem has been widely addressed in literature. Due to its complexity, it is still under consideration for research. This paper addresses flexible job-shop scheduling problem (FJSP) with three objectives to be minimized simultaneously: makespan, maximal machine workload, and total workload. Due to the discrete nature of the FJSP problem, conventional particle swarm optimization (PSO) fails to address this problem and therefore, a variant of PSO for discrete problems is presented. A hybrid discrete particle swarm optimization (DPSO) and simulated annealing (SA) algorithm is proposed to identify an approximation of the Pareto front for FJSP. In the proposed hybrid algorithm, DPSO is significant for global search and SA is used for local search. Furthermore, Pareto ranking and crowding distance method are incorporated to identify the fitness of particles in the proposed algorithm. The displacement of particles is redefined and a new strategy is presented to retain all non-dominated solutions during iterations. In the presented algorithm, pbest of particles are used to store the fixed number of non-dominated solutions instead of using an external archive. Experiments are performed to identify the performance of the proposed algorithm compared to some famous algorithms in literature. Two benchmark sets are presented to study the efficiency of the proposed algorithm. Computational results indicate that the proposed algorithm is significant in terms of the number and quality of non-dominated solutions compared to other algorithms in the literature.     

Reentrant two-stage multiprocessor flow shop scheduling with due windows

Reentrant flow shop scheduling allows a job to revisit a particular machine several times. The topic has received considerable interest in recent years; with related studies demonstrating that particle swarm algorithm (PSO) is an effective and efficient means of solving scheduling problems. By selecting a wafer testing process with the due window problem as a case study, this study develops a farness particle swarm optimization algorithm (FPSO) to solve reentrant two-stage multiprocessor flow shop scheduling problems in order to minimize earliness and tardiness. Computational results indicate that either small- or large-scale problems are involved in which FPSO outperforms PSO and ant colony optimization with respect to effectiveness and robustness. Importantly, this study demonstrates that FPSO can solve such a complex scheduling problem efficiently.     

No-wait two-stage multiprocessor flow shop scheduling with unit setup

A well-arranged production schedule enhances equipment utility rate by distributing limited resources properly, which also improves efficiency and reduces costs. No-wait operations are among the most common production models. A wet batch in semiconductor packaging processes, for instance, is restricted by technical factors such as the chemical dye, which cannot be exposed to air for prolonged periods. Thus, a no-wait process between batches is necessary. This study considers a no-wait two-stage multiprocessor flow shop with setup time that minimizes total completion time. Integer programming model and an ant colony optimization (ACO) heuristic were implemented to test, analyze, and compare simulated data. The ACO results revealed that efficiency was substantially better than that achieved by integer programming, and the heuristic solutions were quite satisfactory.     

Pareto archive particle swarm optimization for multi-objective fuzzy job shop scheduling problems

This paper addresses multi-objective job shop scheduling problems with fuzzy processing time and due-date in such a way to provide the decision-maker with a group of Pareto optimal solutions. A new priority rule-based representation method is proposed and the problems are converted into continuous optimization ones to handle the problems by using particle swarm optimization. The conversion is implemented by constructing the corresponding relationship between real vector and the chromosome obtained with the new representation method. Pareto archive particle swarm optimization is proposed, in which the global best position selection is combined with the crowding measure-based archive maintenance, and the inclusion of mutation into the proposed algorithm is considered. The proposed algorithm is applied to eight benchmark problems for the following objectives: the minimum agreement index, the maximum fuzzy completion time and the mean fuzzy completion time. Computational results demonstrate that the proposal algorithm has a promising advantage in fuzzy job shop scheduling.     

Hybridizing tabu search with ant colony optimization for solving job shop scheduling problems

The manufacturing industry continues to be a prime contributor and it requires an efficient schedule. Scheduling is the allocation of resources to activities over time and it is considered to be a major task done to improve shop-floor productivity. Job shop problem comes under this category and is combinatorial in nature. Research on optimization of the job shop problem is one of the most significant and promising areas of optimization. This paper presents an application of the global optimization technique called tabu search that is combined with the ant colony optimization technique to solve the job shop scheduling problems. The neighborhoods are selected based on the strategies in the ant colony optimization with dynamic tabu length strategies in the tabu search. The inspiring source of ant colony optimization is pheromone trail that has more influence in selecting the appropriate neighbors to improve the solution. The performance of the algorithm is tested using well-known benchmark problems and is also compared with other algorithms in the literature.     

多目标柔性车间调度的Pareto混合禁忌搜索算法

针对最小化最大完成时间、总机床负荷及最大机床负荷的多目标柔性作业车间调度问题,提出了一种带有Pareto档案集的混合禁忌搜索算法.该算法为每次迭代产生的邻域解集进行Pareto非支配排序,选择第一前沿的解用于Pareto档案集更新,并给出了一种Pareto档案集快速更新算法.为减小邻域搜索空间,结合问题特征,设计了基于公共关键块结构的插入邻域和交换邻域.通过3个经典算例的实验仿真,以及与其他算法的比较,验证了该算法的可行性和有效性.     

面向绿色制造的半组合式船用曲轴结构件生产车间多目标调度优化

针对半组合式船用曲轴结构件规格多、批量小、体积质量大、加工精度高、生产能耗大、交货期要求严等特点,以最大完工时间最小、机器加工能耗最小、桥式起重机运输能耗最小为优化目标,研究了该类型曲轴结构件生产车间的绿色调度优化方法.将结构件制造过程细化为准备、装夹、加工、卸夹4个工艺流程,建立了集成桥式起重运输设备与机器加工设备的...     

基于模糊关联熵的高维多目标流水车间调度优化

针对现有优化方法在求解高维多目标问题上的弊端,将多目标解映射为模糊集,提出利用表征模糊集间关联相似程度的模糊关联熵方法解决多目标优化问题。建立基于模糊关联熵的多目标优化方法,以模糊关联熵系数的大小衡量Pareto解模糊集与理想解模糊集的相似程度,并以该系数作为粒子群优化算法适应度值引导算法进化,建立基于模糊关联熵的多目标粒子群优化算法。实验表明,基于模糊关联熵的粒子群优化算法可以有效解决高维多目标Flow Shop调度问题,算法在优化解和各性能指标上皆优于基于随机权重的粒子群优化算法,特别在求解较大规模问题时,基于此法的粒子群优化算法表现更佳。     

A simulated annealing for hybrid flow shop scheduling with multiprocessor tasks to minimize makespan

This paper studies a hybrid flow shop scheduling problem (hybrid FSSP) with multiprocessor tasks, in which a set of independent jobs with distinct processor requirements and processing times must be processed in a k-stage flow shop to minimize the makespan criterion. This problem is known to be strongly nondeterministic polynomial time (NP)-hard, thus providing a challenging area for meta-heuristic approaches. This paper develops a simulated annealing (SA) algorithm in which three decode methods (list scheduling, permutation scheduling, and first-fit method) are used to obtain the objective function value for the problem. Additionally, a new neighborhood mechanism is combined with the proposed SA for generating neighbor solutions. The proposed SA is tested on two benchmark problems from the literature. The results show that the proposed SA is an efficient approach in solving hybrid FSSP with multiprocessor tasks, especially for large problems.     

A cross-docking scheduling problem with sub-population multi-objective algorithms

This paper deals with a scheduling problem of inbound and outbound trucks shipping incoming and outgoing product items into/out of a cross-docking system. We consider an instance of cross-docking systems in which more than one objective are taken into account: minimization of the total operation time (makespan) and minimization of the total lateness of outbound trucks. In order to deal with this problem, three multi-objective algorithms are developed as follows (based on the sub-population concept of evolutionary algorithms): sub-population genetic algorithm-II (SPGA-II), sub-population particle swarm optimization-II (SPPSO-II), and sub-population differential evolution algorithm-II (SPDE-II). In addition, to evaluate the performance of these algorithms, four measures are presented and compared with each other whose results will demonstrate that the SPPSO-II has better characteristics in comparison with other two algorithms.