共查询到19条相似文献,搜索用时 171 毫秒
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项目实施过程中往往受到不同作业之间的资源共享与冲突以及它们之间的先后调度关系的约束,因此在资源受限的情况下如何调度作业以满足该项目的资源要求并缩短整个项目工期是一个重要的问题.在对该问题进行分析的基础上,建立了资源约束下的项目调度问题的数学模型.本文描述的算法基于分支定界法,并进行了优化,在保证各个作业紧前关系与资源约束的条件下,能够合理调度,从而有效地缩短多项目的总工期.通过具体实例的应用和与其他算法的比较,说明了该算法可以得到较好的项目进度计划,并有较高的效率. 相似文献
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通过编制详细的项目进度计划,可降低不可预测风险,提高项目可控性。为实现海工项目的活动调度,优化进度计划,文章基于调度优先规则,针对海工项目活动的并行调度,应用遗传模拟退火算法对给出的四级进度计划进行了优化。首先,根据海洋平台的结构特点对海工项目的四级计划进行编制;其次,给出了项目活动调度的优先规则及并行安排机制;再次,设计了以遗传算法为外层循环,模拟退火算法做内层循环的优化算法;最后,将设计的算法对海工实例进行应用,并实现进度计划的生成。 相似文献
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以集装箱码头船舶装卸作业调度问题为研究对象,综合考虑港口多种装卸资源和流程,在船舶泊位占有时间确定的条件下,以装卸运输作业总成本最低为目标,提出单船装卸作业调度模型;用蚁群算法对所建立的模型进行求解和仿真,并结合实际问题给出具体调度结果。此模型和方法考虑了生产效率和作业成本之间的平衡,保证以较低的成本完成规定作业。 相似文献
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为有效提升船舶曲面分段车间的加工效率,解决已有算法存在的易陷入局部最优解和初始解质量低的问题,提出一种改进的差分进化算法,对曲面分段调度问题进行求解。以最小化完工时间和最小化班组间负荷差距为目标,建立该曲面分段调度问题的双目标数学模型,并采用改进的差分进化算法对该问题进行求解。该改进差分进化算法将全局搜索策略与局部搜索策略相结合,能提升初始解的质量,并加快收敛速度。使用某船厂的实际数据对该算法进行有效性验证,结果表明,该算法能有效求解船舶曲面分段调度问题,能更好地提升船舶曲面分段制造调度作业效率。 相似文献
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针对传统船舶物流调度方法物流运营收益较低的问题,提出一种港口码头大型接卸船舶物流调度方法,对大型接卸船舶泊位资源进行配置,通过设置物流调度条件,建立港口码头大型接卸船舶物流调度模型,利用模拟迭代算法对模型进行求解,实现港口码头大型接卸船舶的物流调度,为了证明该方法的物流运营收益较高,将该方法与基于局部最优解的船舶物流调度方法、基于可能域的船舶物流调度方法、基于改善算法的船舶物流调度方法进行对比实验,结果证明该方法的物流运营收益最高,说明该方法最适用于大型接卸船舶的物流调度。 相似文献
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当前许多面向分布式计算环境的应用对实时系统提出了安全要求,研究安全的实时任务调度算法成为当前的研究热点。文章分析了当前公开文献中各种实时调度算法的缺陷,针对现有算法的不足,提出了一种适用于分布式实时任务的安全调度算法,该算法以提高实时任务的安全性和可调度性为目标,一方面按照任务的不同安全需求为其提供不同级别的安全服务,另一方面采用启发式实时调度技术,在多个处理机上有效分配并运行实时任务。仿真实验的结果表明,文章所提出的算法相对于其他算法而言,在不降低任务可调度性的前提下,有效提高了实时任务的安全性。 相似文献
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Nowadays, shipyards are making every effort to efficiently manage their resources such as gantry cranes, transporters, and
block stock yards. The scheduling of block lifting for a gantry crane has been manually performed by an expert shipyard manager
for many years. Such a practice, however, can lead to an undesirably long time to produce scheduling plans. In addition, the
quality of the scheduling plans may not be optimal. To improve the overall process, a block lifting scheduling system for
a gantry crane was developed in this study by using optimization techniques. A block lifting scheduling problem was first
formulated as a multiobjective optimization problem. For a gantry crane, minimization of the traveling distance while unloaded
and wire and shackle replacement between block lifting was considered. An optimization algorithm based on the genetic algorithm
was then proposed and implemented so as to solve the problem. To evaluate the efficiency and applicability of the developed
system, the system was applied to an actual block lifting scheduling problem in a shipyard. Compared to results achieved by
manual scheduling by an expert manager, the results of this work show that blocks can be more efficiently lifted by a gantry
crane when the developed system is applied. 相似文献
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Shangyao Yan Chun-Ying Chen Shih-Chun Lin 《Journal of Marine Science and Technology》2009,14(4):417-435
Good short-term ship scheduling and container shipment planning are very important for liner operations; however, in Taiwan,
most such carriers currently utilize a trial-and-error process. In this study, we employ network flow techniques to construct
a model for such activities. A solution algorithm, based on Lagrangian relaxation, a subgradient method, and a heuristic for
the upper-bound solution, is developed to solve the model. To demonstrate and to test how well the model and the solution
algorithm apply in the real world, we performed a case study using operating data from a major Taiwanese marine shipping company.
The test results show that the model and the solution algorithm could be useful references for ship scheduling and container
shipment planning. 相似文献
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