基于二维可变邻域编码方式的混合遗传算法

针对现有混合遗传算法无法兼顾有效性及高效性的问题,提出一种基于二维可变邻域编码方式的新型混合遗传算法(VNHGA)。首先提出了一种将个体“基因型”与“邻域型”分开编码、同步遗传的新型编码方式,以替换传统二进制编码方式;然后设计了一种稳定变异算子,以替换传统变异算子来提高效率。通过多维函数最小值问题对VNHGA进行测试:首先验证采用所提二维可变邻域编码方式后,使用“鲍德温(Baldwin)效应”作为将局部搜索嵌入传统遗传算法策略时,相对于基于“拉马克(Lamarckian)进化”的嵌入策略,仍然具有采用传统二进制编码方式时的特性,即具有良好有效性但高效性不足;其次验证引入稳定变异算子后,算法在保持其有效性的同时提升了效率,运行时间缩短到之前的50%左右;最后,与两种改进混合遗传算法进行比较,验证所提算法优势。结果表明VNHGA兼具有效性与高效性特点,可用于解决最优化问题。     

An improved scatter search algorithm for the single machine total weighted tardiness scheduling problem with sequence-dependent setup times

In this paper, a scatter search algorithm with improved component modules is proposed to solve the single machine total weighted tardiness problem with sequence-dependent setup times. For diversification generation module, both random strategy based heuristics and construction heuristic are adopted to generate the diversified population. For improvement module, variable neighborhood search based local searches are embedded into the algorithm to improve the trial solutions and the combined solutions. For reference set update module, the number of edges by which the two solutions differ from each other is counted to measure the diversification value between two solutions. We also propose a new strategy in which the length of the reference set could be adjusted adaptively to balance the computing time and solving ability. In addition, a discrete differential evolution operator is proposed with another two operators constitute the combination module to generate the new trial solutions with the solutions in the subsets. The proposed algorithm is tested on the 120 benchmark instances from the literature. Computational results indicate that the average relative percentage deviations of the improved algorithm from the ACO_AP, DPSO, DDE and GVNS are −5.16%, −3.33%, −1.81% and −0.08%, respectively. Comparing with the state-of-the-art and exact algorithms, the proposed algorithm can obtain 78 optimal solutions out of 120 instances within a reasonable computational time.     

A population-based variable neighborhood search for the single machine total weighted tardiness problem

This paper investigates the single machine total weighted tardiness problem, in which a set of independent jobs with distinct processing times, weights, and due dates are to be scheduled on a single machine to minimize the sum of weighted tardiness of all jobs. This problem is known to be strongly NP-hard, and thus provides a challenging area for metaheuristics. A population-based variable neighborhood search (PVNS) algorithm is developed to solve it. This algorithm differs from the basic variable neighborhood search (VNS). First, the PVNS consists of a number of iterations of the basic VNS, and in each iteration a population of solutions is used to simultaneously generate multiple trial solutions in a neighborhood so as to improve the search diversification. Second, the PVNS adopts a combination of path-relinking, variable depth search and tabu search to act as the local search procedure so as to improve the search intensification. Computational experiments show that the proposed PVNS algorithm can obtain the optimal or best known solutions within a reasonable computation time for all standard benchmark problem instances from the literature.     

批量流水线调度问题的混合差分进化算法

针对E/T指标的批量流水线调度问题,提出了差分进化调度算法。该算法采用基于实数的编码方式,利用最优目标个体的扰动产生变异个体,通过变异个体与目标个体的交叉产生试验个体,提高了最优目标个体信息共享,并结合模拟退火算法给出了两种混合求解策略。仿真试验表明了所得算法的可行性和高效性。     

Minimizing Total Weighted Tardiness in a Generalized Job Shop

We consider a generalization of the classical job shop scheduling problem with release times, positive end–start time lags, and a general precedence graph. As objective we consider the total weighted tardiness. We use a tabu search algorithm to search for the order in which the operations are processed on each machine. Given a sequence of operations on each machine, we determine optimal starting times by solving a maximum cost flow problem. This solution is used to determine the neighborhood for our tabu search algorithm. All sequences in our neighborhood are obtained by swapping certain pairs of adjacent operations. We show that only swaps that possess a certain property can improve the current solution; if no such swap is available in the neighborhood, then the current solution is globally optimal. In the computational results we compare our method with other procedures proposed in literature. Our tabu search algorithm seems to be effective both with respect to time and solution quality. The research was carried out at the Technische Universiteit Eindhoven and the Universiteit Utrecht with support of Baan and the Future and Emerging Technologies programme of the EU under contract number IST-1999-14186 (ALCOM-FT).     

变邻域搜索算法求解机器人制造单元调度问题——排序依赖转换时间

针对排序依赖转换时间的两机器机器人制造单元调度问题的NP难特性,设计了变邻域搜索算法求解。为了加快算法收敛速度,设计了工件阻塞时间最小化生成初始解;为了搜索到更好解,分析了算法的参数取值。通过随机产生算例测试,提出算法优于模拟退火算法,证实了提出算法的有效性。     

基于拉马克进化的差分进化算法求解KPC问题

具有单连续变量的背包问题(knapsack problem with a single continuous variable,KPC)是标准0-1背包问题的自然推广,在KPC中背包容量不是固定的,因此其求解难度变大.针对现有差分进化(differential evolution,DE)算法在高维KPC实例上求解精度不...     

混和进化算法求解具有分段恶化效应的并行机调度问题

本文提出了一种新的混合进化算法求解具有线性恶化的并行机调度问题,目标是使总完工时间最小.该算法采用对立策略以及最小比率优先规则生成初始种群,并且引入种群多样度指标加快算法的收敛;同时加入含有3-opt扰动算子的变邻域搜索算法对遗传算法得到的结果进行局部搜索.通过对不同规模算例的实验进行仿真,其结果与传统GA和VNS算法相比,效果均有所提升.     

基于超网络的集成工艺决策与调度问题研究

针对多工艺产品的加工路线决策与车间调度方案不能同步制定的问题,在制造车间数字化背景下,提出集成车间不同要素信息的特征—工序—机器—工人的超网络结构,建立基于超网络的加工路线决策与车间调度模型,设计一种集成工艺决策与车间调度的两阶段混合遗传算法求解模型。在工艺决策阶段,设计特征—工序双层矩阵编码染色体保持加工路线的多样性,并在遗传算法的执行过程中使用变邻域搜索方法增强算法的局部搜索能力;在车间调度阶段,采用NSGA-Ⅱ算法优化调度模型,将得到的调度方案多目标值返回至工艺决策阶段用于加工路线的适应度评价。最后通过仿真实验验证了该算法的可行性与有效性。     

A genetic local search algorithm for minimizing total weighted tardiness in the job-shop scheduling problem

This paper considers the job-shop problem with release dates and due dates, with the objective of minimizing the total weighted tardiness. A genetic algorithm is combined with an iterated local search that uses a longest path approach on a disjunctive graph model. A design of experiments approach is employed to calibrate the parameters and operators of the algorithm. Previous studies on genetic algorithms for the job-shop problem point out that these algorithms are highly depended on the way the chromosomes are decoded. In this paper, we show that the efficiency of genetic algorithms does no longer depend on the schedule builder when an iterated local search is used. Computational experiments carried out on instances of the literature show the efficiency of the proposed algorithm.     

Variable neighborhood search approaches for scheduling jobs on parallel machines with sequence-dependent setup times, precedence constraints, and ready times

In this paper, we discuss a scheduling problem for jobs on identical parallel machines. Ready times of the jobs, precedence constraints, and sequence-dependent setup times are considered. We are interested in minimizing the performance measure total weighted tardiness that is important for achieving good on-time delivery performance. Scheduling problems of this type appear as subproblems in decomposition approaches for large scale job shops with automated transport of the jobs as, for example, in semiconductor manufacturing. We suggest several variants of variable neighborhood search (VNS) schemes for this scheduling problem and compare their performance with the performance of a list based scheduling approach based on the Apparent Tardiness Cost with Setups and Ready Times (ATCSR) dispatching rule. Based on extensive computational experiments with randomly generated test instances we are able to show that the VNS approach clearly outperforms heuristics based on the ATCSR dispatching rule in many situations with respect to solution quality. When using the schedule obtained by ATCSR as an initial solution for VNS, then the entire scheme is also fast and can be used as a subproblem solution procedure for complex job shop decomposition approaches.     

长期车辆合乘问题的复合变邻域搜索算法

针对于长期车辆合乘问题（LTCPP）,提出一种复合变邻域搜索算法（HVNSA）,将具有相同目的地的用户进行合乘匹配从而减少车辆出行数量。首先,构建一个全面准确的长期车辆合乘问题的数学模型,将所有用户按复合距离优先算法分配到合乘小组中,对时间窗口和车容量约束验证,得到初始合乘方案;然后利用变邻域搜索算法对初始合乘方案进行优化迭代,得到最终的优化合乘方案。实验结果表明,该算法在处理100人和200人的规模问题上可以在1 s内得到高质量的优化合乘方案,对于400人和1000人的较大规模问题,该算法仍然可以在2~4 s内得到较高质量的优化合乘方案。     

A note on “Beam search heuristics for the single machine early/tardy scheduling problem with no machine idle time”

In a recent paper by Valente “Beam search heuristics for the single machine early/tardy scheduling problem with no machine idle time”’, Computers & Industrial Engineering, 55, 663–675, 2008, several beam search approaches are compared on a large set of instances of the total weighted earliness-tardiness problem on single machine with jobs independent weights and no machine idle time. That problem is denoted 1|nmit|_∑jhEj+_∑jwTj$1|\mathit{nmit}|{\sum }_j{\mathit{hE}}_j+{\sum }_j{\mathit{wT}}_j$. This note points out that the standard iterated dynasearch procedure applied to that problem outperforms all the literature heuristics. Based on these results and others obtained on similar problems, we conclude that dynasearch for its efficiency and simplicity, should be used as a benchmark for future heuristics on those types of single machine no idle time problems.     

A variable neighborhood search for minimizing total weighted tardiness with sequence dependent setup times on a single machine

This paper deals with the single machine scheduling problem to minimize the total weighted tardiness in the presence of sequence dependent setup. Firstly, a mathematical model is given to describe the problem formally. Since the problem is NP-hard, a general variable neighborhood search (GVNS) heuristic is proposed to solve it. Initial solution for the GVNS algorithm is obtained by using a constructive heuristic that is widely used in the literature for the problem. The proposed algorithm is tested on 120 benchmark instances. The results show that 37 out of 120 best known solutions in the literature are improved while 64 instances are solved equally. Next, the GVNS algorithm is applied to single machine scheduling problem with sequence dependent setup times to minimize the total tardiness problem without changing any implementation issues and the parameters of the GVNS algorithm. For this problem, 64 test instances are solved varying from small to large sizes. Among these 64 instances, 35 instances are solved to the optimality, 16 instances' best-known results are improved, and 6 instances are solved equally compared to the best-known results. Hence, it can be concluded that the GVNS algorithm is an effective, efficient and a robust algorithm for minimizing tardiness on a single machine in the presence of setup times.     

基于差分进化算法的FMS中机器与多载AGV调度

针对柔性制造系统中机器与混合多载自动导引搬运车(automated guided vehicle,AGV)集成调度问题,以最小化最大完工时间为目标,提出一种改进混合离散差分进化算法,通过离散操作进行差分进化算法的变异、交叉,并对每次迭代的最优个体进行变邻域搜索.设计基于搬运任务、机器和AGV的3层编码结构,并进行合理化调整;设计基于关键路径的变邻域搜索,有针对性地调整关键路径上任务的次序、对应工序的机器和AGV,提高局部搜索效率;设计基于外部档案的个体更新策略,将种群中较差的个体从外部档案中进行替换,提高全局搜索效率.最后,通过实验验证算法改进策略的有效性以及所提出算法的有效性,分析AGV数量、AGV载位容量以及AGV电池可用时间对算法求解结果和改进效果的影响.     

A discrete differential evolution algorithm for the single machine total weighted tardiness problem with sequence dependent setup times

This paper is concerned with solving the single machine total weighted tardiness problem with sequence dependent setup times by a discrete differential evolution algorithm developed by the authors recently. Its performance is enhanced by employing different population initialization schemes based on some constructive heuristics such as the well-known NEH and the greedy randomized adaptive search procedure (GRASP) as well as some priority rules such as the earliest weighted due date (EWDD) and the apparent tardiness cost with setups (ATCS). Additional performance enhancement is further achieved by the inclusion of a referenced local search (RLS) in the algorithm together with the use of destruction and construction (DC) procedure when obtaining the mutant population. Furthermore, to facilitate the greedy job insertion into a partial solution which will be employed in the NEH, GRASP, DC heuristics as well as in the RLS local search, some newly designed speed-up methods are presented for the insertion move for the first time in the literature. They are novel contributions of this paper to the single machine tardiness related scheduling problems with sequence dependent setup times. To evaluate its performance, the discrete differential evolution algorithm is tested on a set of benchmark instances from the literature. Through the analyses of experimental results, its highly effective performance with substantial margins both in solution quality and CPU time is shown against the best performing algorithms from the literature, in particular, against the very recent newly designed particle swarm and ant colony optimization algorithms of Anghinolfi and Paolucci [A new discrete particle swarm optimization approach for the single machine total weighted tardiness scheduling problem with sequence dependent setup times. European Journal of Operational Research 2007; doi:10.1016/j.ejor.2007.10.044] and Anghinolfi and Paolucci [A new ant colony optimization approach for the single machine total weighted tardiness scheduling problem. http://www.discovery.dist.unige.it/papers/Anghinolfi_Paolucci_ACO.pdf, respectively. Ultimately, 51 out of 120 overall aggregated best known solutions so far in the literature are further improved while other 50 instances are solved equally.     

柔性车间调度的解空间距离聚类和变邻域搜索粒子群算法

根据柔性车间调度问题提出基于解空间距离聚类和变邻域搜索的粒子群算法.在粒子群算法基础上采用贪婪策略引入变邻域搜索方式,即调整关键路径上最大关键工序的机器位置,调整关键路径上工序相对位置变化,加强局部搜索能力;根据机器加工工序的空间距离,采用K-means聚类得到机器加工工序“优良个体”,加大局部搜索性能.同时对于粒子群算法速度更新采用局部停滞策略,保留局部片段相对位置不变特性.通过实验仿真,优化算法取得了较好的效果,与一般的粒子群算法相比较收敛速度迅速且性能良好.     

改进型蝙蝠算法在作业车间调度问题中的应用

针对一类以最小化最大完工时间为目标的作业车间调度问题（Job Shop scheduling Problem,JSP）,提出了一种改进型蝙蝠算法（Improved Bat Algorithm,IBA）。为了克服基本蝙蝠算法在求解该类离散组合优化问题存在的局限性,首先对编码方案进行了设计,实现了算法中离散问题的连续编码;然后采用基于G&T算法和随机生成的方法初始化种群,以提高初始解的质量。此外,还引入了变邻域搜索策略,以避免算法早熟收敛,提高IBA算法的性能。最后,基于JSP问题的基准算例进行了大量仿真对比实验,结果显示了IBA算法的可行性和有效性。