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针对最小化最大完工时间的柔性流水车间调度问题,文章提出了多目标选择的改进的遗传算法(MTGA),设计了针对该问题的一维的编码与解码方法,采用对立的方法进行种群的初始化。针对遗传算法,交叉操作进行整个工序的交叉向最优解靠拢加快了算法的收敛速度,变异操作中对所有的工序操作顺序进行整体变异,选择操作将种群分成多份做到向多个较优解靠拢,扩大了算法的搜索范围,降低了陷入局部最优的概率,并应用了两套交叉和变异概率增加算法灵活性。通过多个已有算法进行对比验证了算法的有效性。 相似文献
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机加车间排产优化是降低生产成本,提高加工效率,增强企业市场竞争力的重要措施,遗传算法作为一种高效的优化算法在求解排产问题中得到广泛应用。以加工时间最短为目标,对机加车间工件加工问题建立数学模型。针对标准遗传算法(SGA)求解存在的早熟收敛、求解精度低等问题,提出一种改进的遗传算法。为获得更好的基因结构,以个体适应度值为参照自动调节交叉概率和变异概率。为避免无效解,根据加工任务高度值划分基因段来改善交叉操作。为增强算法的全局搜索能力,引入混沌理论优化变异算子。仿真结果表明改进的遗传算法较SGA有更好的收敛性和全局搜索能力,对机加车间排产优化效果明显。 相似文献
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为了根据用户的请求实现Web服务的自动组合,在保证服务质量的前提下最大化地提高服务效率,针对Web服务组合中的服务质量感知问题,引入混沌的概念,提出一种基于混沌遗传算法的Web服务组合方法。该方法利用混沌理论产生种群的初始群体,根据遗传算法的选择、交叉、变异操作实现种群进化,通过对每次进化后的子代群体附加混沌小扰动有效地克服了遗传算法早熟和收敛速度慢的缺点。实验表明,该方法可以获得比现有混沌遗传算法更快的收敛速度和更高的可靠性。 相似文献
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为综合考虑资源约束型项目调度问题的多个调度目标,有效获得该问题的近似非支配解集,建立了一种综合考虑可更新资源稳定性和工期的双目标项目调度模型。提出了一种基于Pareto排序和多目标混沌加权相结合的遗传算法,其中个体编码采用双链表结构,分别代表任务的执行顺序和执行模式,初始种群的生成包括随机生成和依据任务特性确定执行模式两种方式,设计了个体交叉和自适应变异算子,研究了基于Pareto排序法和基于多目标混沌加权法的个体适应度计算方法以及不可行解的修复和惩罚策略。利用项目调度问题算例库对该算法进行测试,数值测试结果验证了算法的有效性。 相似文献
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基于改进自适应遗传算法的网格任务调度算法 总被引:3,自引:0,他引:3
肖莉萍 《中国制造业信息化》2009,38(1)
针对网格环境动态多变性的特点,对网格环境任务调度中的遗传算法进行研究,提出一种改进的自适应遗传算法.通过对影响遗传算法行为和性能的关键参数交叉概率与变异概率进行分析,提出利用自适应思想以及表征调度性能的种群适应度对交叉概率和变异概率合理选取的自适应遗传算法,使交叉概率和变异概率能随种群适应度自动调节、改变.试验结果表明,改进的自适应遗传算法能使网格任务调度具有较好的种群自适应度,从而表明该方法的有效性. 相似文献
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为满足动态多变的产品需求,研究了知识化制造产品工艺路线自重构问题.以最小化平均在制品水平和最小化重构后各工序在机器上的分配变动数目为目标,在满足生产率、工序优先顺序、工件加工完整性、机器加工可行性约束的前提下,对产品工艺路线重构问题进行数学建模.提出了改进的混沌非支配排序遗传算法,利用带随机参数的Skew Tent映射对种群个体进行扰动,避免搜索陷入局部最优.设计了基于工序优先约束矩阵和候选机器集的解码方法,可获得产品可行的加工工序序列及加工机器序列.通过实例研究验证了模型和算法的有效性,为决策者提供了多种可选工艺路线重构方案. 相似文献
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具有零等待约束条件的流水车间调度问题是一类典型的NP难问题,针对该问题提出一种新型混合改进遗传算法进行优化求解.首先,采用改进NEH算法强化初始种群质量,提高种群的多样性.结合关联规则理论挖掘种群中的优势块,借助优势块进行人工染色体组合,以降低问题复杂度.交叉操作采用单段交叉、双段交叉和三段交叉3种交叉机制,改善算法全... 相似文献
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Tung-Kuan Liu Jinn-Tsong Tsai Jyh-Horng Chou 《The International Journal of Advanced Manufacturing Technology》2006,27(9-10):1021-1029
In this paper, an improved genetic algorithm, called the hybrid Taguchi-genetic algorithm (HTGA), is proposed to solve the job-shop scheduling problem (JSP). The HTGA approach is a method of combining the traditional genetic algorithm (TGA), which has a powerful global exploration capability, with the Taguchi method, which can exploit the optimal offspring. The Taguchi method is inserted between crossover and mutation operations of a TGA. Then, the systematic reasoning ability of the Taguchi method is incorporated in the crossover operations to systematically select the better genes to achieve crossover, and consequently enhance the genetic algorithm. Therefore, the proposed HTGA approach possesses the merits of global exploration and robustness. The proposed HTGA approach is effectively applied to solve the famous Fisher-Thompson benchmarks of 10 jobs to 10 machines and 20 jobs to 5 machines for the JSP. In these studied problems, there are numerous local optima so that these studied problems are challenging enough for evaluating the performances of any proposed GA-based approaches. The computational experiments show that the proposed HTGA approach can obtain both better and more robust results than other GA-based methods reported recently. 相似文献
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Shun-Fa Hwang Ya-Chu Hsu Yuder Chen 《Journal of Mechanical Science and Technology》2014,28(8):3163-3169
A genetic algorithm for the optimization of composite laminates is proposed in this work. The well-known roulette selection criterion, one-point crossover operator, and uniform mutation operator are used in this genetic algorithm to create the next population. To improve the hill-climbing capability of the algorithm, adaptive mechanisms designed to adjust the probabilities of the crossover and mutation operators are included, and the elite strategy is enforced to ensure the quality of the optimum solution. The proposed algorithm includes a new operator called the elite comparison, which compares and uses the differences in the design variables of the two best solutions to find possible combinations. This genetic algorithm is tested in four optimization problems of composite laminates. Specifically, the effect of the elite comparison operator is evaluated. Results indicate that the elite comparison operator significantly accelerates the convergence of the algorithm, which thus becomes a good candidate for the optimization of composite laminates. 相似文献
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根据KAM定理,分析了一种新型的混沌激振器——端面式混沌激振器.建立了端面式混沌激振器的数学模型,并对其进行了数值仿真,识别端面式激振器是否具有混沌性.结果表明端面式混沌激振器具有混沌性. 相似文献
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An improved genetic algorithm for job-shop scheduling problems using Taguchi-based crossover 总被引:1,自引:1,他引:0
Jinn-Tsong Tsai Tung-Kuan Liu Wen-Hsien Ho Jyh-Horng Chou 《The International Journal of Advanced Manufacturing Technology》2008,38(9-10):987-994
A Taguchi-based genetic algorithm (TBGA) is proposed as an improved genetic algorithm to solve the job-shop scheduling problems (JSP). The TBGA combines the powerful global exploration capabilities of conventional genetic algorithm (GA) with the Taguchi method that exploits optimal offspring. The latter method is used as a new crossover and is incorporated in the crossover operation of a GA. The reasoning ability of the Taguchi-based crossover can systematically select the better genes to achieve crossover and, consequently, enhance the GA. Furthermore, mutation is designed to have the neighbor search technique of performing the fine-tuning on the positions of jobs for the JSP. Therefore, the proposed TBGA approach possesses the merits of global exploration and robustness. The proposed TBGA approach is effectively applied to solve the famous Fisher-Thompson and Lawrence benchmarks of the JSP. In these studied problems, there are numerous local optima so that these studied problems are challenging enough for evaluating the performances of any proposed evolutionary approaches. The computational experiments show that the proposed TBGA approach can obtain both better and more robust results than those evolutionary methods reported recently. 相似文献
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针对理论上属于NP完全问题的矩形件优化排样问题,提出了一种基于小生境技术的自适应遗传模拟退火算法。研究了将矩形件在板材上的排列方式转换为特定编码的方法,利用遗传模拟退火算法进行全局优化概率搜索,考虑到算法中交叉概率和变异概率的选择影响到算法收敛性,提出了自适应的交叉概率和变异概率,并通过小生境技术对子辈个体是否替换父辈个体加以控制,最终得到矩形件排样的最优次序和排放方式,采用最低水平线策略的启发式排样算法实现自动排样。排样实例表明,该优化排样算法行之有效,具有广泛的适应性。 相似文献
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多工艺路线多资源多目标的作业调度优化 总被引:5,自引:1,他引:5
针对多工艺路线多加工资源多目标的作业调度问题,提出了一种启发式活动调度算法,将该方法与多目标遗传算法及模糊优选技术相结合,得到了一种新调度算法.基于工序的染色体编码方法和基于活动启发式算法的交叉算子的运用,有效地缩小了遗传算法的搜索空间.将随机产生的权系数与模糊优选技术相结合,有助于遗传算法搜索到多个优良的调度方案,这为决策者得到最满意的调度方案提供了保证.仿真结果表明该算法是可行的,与国外学者的同类研究相比,具有一定的优越性. 相似文献
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根据KAM定理,分析了一种新型的混沌激振器——端面式混沌激振器。建立了端面式混沌激振器的数学模型,并对其进行了数值仿真,识别端面式激振器是否具有混沌性。结果表明端面式混沌激振器具有混沌性。 相似文献
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Daoshan Du Yadong Liu Xingui Guo Kazuo Yamazaki Makoto Fujishima 《The International Journal of Advanced Manufacturing Technology》2009,44(11-12):1181-1190
In this paper, we propose a flow shop scheduling problem with no-wait flexible lot streaming. The problem involves the splitting of order quantities of different products into sublots and considers alternative machines with different processing times. Sublots of a particular product are not allowed to intermingle; that is, sublots of different products must be non-preemptive. The objective of the problem is the minimization of the makespan. An adaptive genetic algorithm (GA) is proposed, which is composed of three main steps. The first step is a position-based crossover of products and local-search-based mutation for better offspring. The second step is an iterative hill-climbing algorithm to improve the current generation. The last step is the adaptive regulation of the crossover and mutation rates. Experimental results are presented for various sizes of problems to describe the performance of the proposed algorithm and they show promising outcome compared to traditional GAs. 相似文献