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1.
针对多产品生产部件串联系统的生产和维修问题进行了研究,提出了基于二阶段时间延迟的联合优化模型。首先,基于生产周期分段理论,将整个周期等分成若干单位时间段,生产与维修共用每段时间,且若干时间段后采取一次预防维修。其次,考虑生产系统的实际生产时间、可用生产时间和维修耗费时间,建立了生产计划与维修计划总成本模型。其中,维修计划考虑缺陷和故障维修费用、维修检查费用,以及非正常状态下设备运行可能产生的不合格产品损失费用;生产计划考虑生产成本、库存成本、延期未交货成本和维修停机后恢复生产的设备启动成本。最后,通过算例分析,计算最优预防维修周期和各单位时间段各产品产量,验证了模型的有效性。  相似文献   

2.
生鲜农产品冷链物流低碳配送路径优化研究   总被引:1,自引:0,他引:1       下载免费PDF全文
综合考虑配送车辆的固定成本、运输成本、生鲜农产品的货损成本、制冷成本、配送过程中产生的碳排放成本,以及因未满足客户要求的服务时间窗而产生的惩罚成本作为目标函数,构建考虑碳排放的生鲜农产品配送路径优化模型,提出了解决该问题的一种结合2-opt局部搜索机制的改进蚁群算法,并用实例对模型及算法的有效性进行验证,同时对算法参数进行了敏感性分析。仿真实验及算法对比结果证明模型和算法是有效的,可以为物流企业的配送决策提供参考。  相似文献   

3.
部分短缺量拖后且考虑费用时值的VM I 模型   总被引:5,自引:0,他引:5  
罗兵  杨帅  卢娜 《控制与决策》2005,20(9):1061-1064
针对一般的供应商管理库存(VMI)模型通常忽略系统的费用时值问题,基于需求为常数和无短缺量拖后或短缺量完全拖后的VMI模型,进一步考虑系统的费用时值和缺货期间出现短缺量部分拖后的情况,建立了包括一个供应商和一个订货商、从原材料到产成品的VMI模型,通过数值仿真和灵敏度分析表明,最优解存在且费用贴现率、丢单系数与服务水平对供应链各成员的单项和集成总成本均有不同程度的影响,为VMI系统的管理决策提供了理论依据。  相似文献   

4.
Resource leveling and time–cost tradeoff are among the most challenging optimization problems in project management. These two problems are usually addressed separately because each problem optimizes different objective functions. In this paper, we develop an integrated model that addresses both problems when activities are allowed to split for better utilization of resources. The formulated mixed integer linear program (MILP) model considers the tradeoff between the crashing‐dependent costs; direct and indirect costs, and resource utilization related costs; acquiring, releasing, and splitting costs. The model can be used as a decision tool to determine whether crashing is recommended when decision makers are also concerned with the better utilization of project's resources. A one‐way sensitivity analysis was conducted to assess total cost savings achieved through the integration of time–cost tradeoff and resource leveling problems. Another experimental study was undertaken to evaluate the performance of the MILP runtime.  相似文献   

5.
We investigate the data-parallel implementation of a set of "information filters" used to rule out uninteresting data from a database or data stream. We develop an analytic model for the costs and advantages of load rebalancing for the parallel filtering processes, as well as a quick heuristic for its desirability. Our model uses binomial models of the filter processes and fits key parameters to the results of extensive simulations. Experiments confirm our model. Rebalancing should pay off whenever processor communications costs are high. Further experiments showed it can also pay off even with low communications costs for 16-64 processes and 1-10 data items per processor; then, imbalances can increase processing time by up to 52 percent in representative cases, and rebalancing can increase it by 78 percent, so our quick predictive model can be valuable. Results also show that our proposed heuristic rebalancing criterion gives close to optimal balancing. We also extend our model to handle variations in filter processing time per data item  相似文献   

6.
为适应经济全球化对运输效率的发展要求,针对集装箱多式联运系统中各种运输线路以及运输方式的组合模式进行了研究。分析了集装箱多式联运过程中影响运输时间以及运输费用的因素,详细描述了多式联运网络,建立了以时间为约束的集装箱多式联运系统运输费用组合优化模型,对集装箱多式联运过程中各种运输线路和运输方式的组合模式进行了定量分析,通过对1个算例进行仿真证明了模型的有效性。  相似文献   

7.
在基于G-O模型的软件可靠性增长模型中引入以时间为变量故障察觉率,并以此模型建立了一种新的软件费用模型。该费用模型考虑了软件发布后使用者对软件系统剩余故障的发现概率,并不是所有的剩余故障全部被发现这种情况,使模型更符合实际。以软件开发费用最小为最优化条件,讨论发布时间与费用的关系,并在文章最后用示例说明了发布时间随参数变化。  相似文献   

8.
研究了能力约束的有限计划展望期生产计划问题,各周期的需求随机,库存产品存在变质且变质率为常数。建立了问题的期望值模型,目标函数为极小化生产准备成本、生产成本、库存成本的期望值。提出了随机模拟、遗传算法和启发式算法相结合的求解算法。用数值实例对模型和算法进行了验证,优化结果表明模型和算法是有效的。  相似文献   

9.
This paper studies a vehicle routing problem with soft time windows and stochastic travel times. A model is developed that considers both transportation costs (total distance traveled, number of vehicles used and drivers' total expected overtime) and service costs (early and late arrivals). We propose a Tabu Search method to solve this model. An initialization algorithm is developed to construct feasible routes by taking into account the travel time stochasticity. Solutions provided by the Tabu Search algorithm are further improved by a post-optimization method. We conduct our computational experiments for well-known problem instances. Results show that our Tabu Search method performs well by obtaining very good final solutions in a reasonable amount of time.  相似文献   

10.
针对目前研究冷链物流车辆路径问题多未考虑交通拥堵对运营成本的影响,将道路拥堵因素融入到冷链物流绿色车辆路径(Green Vehicle Routing Problem)优化数学模型中。兼顾经济成本和环境成本,在时变网络下综合考虑冷链物流中车辆管理成本、运输能耗成本、货损成本、制冷成本以及客户需求时间窗的惩罚成本,同时引入运输和制冷过程中产生的碳排放成本,统筹安排车辆路径,使得物流企业整体运营成本最低,更绿色环保。在此基础上根据模型特点设计改进蚁群算法进行求解,用实例对模型和算法进行仿真,验证该模型和方法可以有效地规避拥堵时段,降低配送成本,促进物流企业的节能减排,可以为物流企业冷链配送路径决策提供良好的参考依据。  相似文献   

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