排序方式: 共有74条查询结果,搜索用时 156 毫秒
41.
基于马尔可夫分析理论,给出了人才拥有量预测的马尔可夫模型,并且讨论了模型中转移概率的确定及模型的预测质量等问题. 相似文献
42.
Mark E. Ferguson 《海军后勤学研究》2003,50(8):917-936
Negotiations between an end product manufacturer and a parts supplier often revolve around two main issues: the supplier's price and the length of time the manufacturer is contractually held to its order quantity, commonly termed the “commitment time frame.” Because actual demand is unknown, the specification of the commitment time frame determines how the demand risk is shared among the members of the supply chain. Casual observation indicates that most manufacturers prefer to delay commitments as long as possible while suppliers prefer early commitments. In this paper, we investigate whether these goals are always in the firm's best interest. In particular, we find that the manufacturer may sometimes be better off with a contract that requires an early commitment to its order quantity, before the supplier commits resources and the supplier may sometimes be better off with a delayed commitment. We also find that the preferred commitment time frame depends upon which member of the supply chain has the power to set their exchange price. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003 相似文献
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使用保障资源的确定方法探讨 总被引:3,自引:0,他引:3
在使用保障过程中需要9项使用保障资源,包括人力与人员、保障设备、技术资料、训练与训练保障、计算机资源保障、保障设施、储存和运输、能源、弹药等。其中人力与人员、使用保障设备2项内容与使用保障联系最为紧密,在装备的研制阶段就应考虑确定。主要讨论了用相似系统法确定人力与人员的数量,用排队论确定保障设备的品种和数量。 相似文献
44.
对抗的战场环境和任务的变化,越来越需要装备战备完好性来保障作战行动。保持或提高装备战备完好性是装备保障的核心和中心工作。利用基于结构风险最小化的支持向量分类(Support Vector Classification,SVC)方法对装备的战备完好性进行了预测,提高了机器学习方法的预测能力。并以车辆装备发动机的技术状况数据为实例,建立了预测模型,通过参数选择,提高了模型预测的正确率、命中率等指标。结论表明:支持向量分类方法是预测装备战备完好性的有效方法。 相似文献
45.
There has been a dramatic increase over the past decade in the number of firms that source finished product from overseas. Although this has reduced procurement costs, it has increased supply risk; procurement lead times are longer and are often unreliable. In deciding when and how much to order, firms must consider the lead time risk and the demand risk, i.e., the accuracy of their demand forecast. To improve the accuracy of its demand forecast, a firm may update its forecast as the selling season approaches. In this article we consider both forecast updating and lead time uncertainty. We characterize the firm's optimal procurement policy, and we prove that, with multiplicative forecast revisions, the firm's optimal procurement time is independent of the demand forecast evolution but that the optimal procurement quantity is not. This leads to a number of important managerial insights into the firm's planning process. We show that the firm becomes less sensitive to lead time variability as the forecast updating process becomes more efficient. Interestingly, a forecast‐updating firm might procure earlier than a firm with no forecast updating. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009 相似文献
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47.
基于MSOA神经网络模型的装备保障费用预测 总被引:1,自引:0,他引:1
引入基于多步骤优化方法(MSOA)神经网络模型用以预测装备保障费用。实验结果表明,与传统的ARIMA时间序列模型和常规BP神经网络模型相比,基于MSOA神经网络预测模型具有更高预测精度。因此,该模型是一种更有效的装备保障费用预测模型。 相似文献
48.
We consider an expansion planning problem for Waste‐to‐Energy (WtE) systems facing uncertainty in future waste supplies. The WtE expansion plans are regarded as strategic, long term decisions, while the waste distribution and treatment are medium to short term operational decisions which can adapt to the actual waste collected. We propose a prediction set uncertainty model which integrates a set of waste generation forecasts and is constructed based on user‐specified levels of forecasting errors. Next, we use the prediction sets for WtE expansion scenario analysis. More specifically, for a given WtE expansion plan, the guaranteed net present value (NPV) is evaluated by computing an extreme value forecast trajectory of future waste generation from the prediction set that minimizes the maximum NPV of the WtE project. This problem is essentially a multiple stage min‐max dynamic optimization problem. By exploiting the structure of the WtE problem, we show this is equivalent to a simpler min‐max optimization problem, which can be further transformed into a single mixed‐integer linear program. Furthermore, we extend the model to optimize the guaranteed NPV by searching over the set of all feasible expansion scenarios, and show that this can be solved by an exact cutting plane approach. We also propose a heuristic based on a constant proportion distribution rule for the WtE expansion optimization model, which reduces the problem into a moderate size mixed‐integer program. Finally, our computational studies demonstrate that our proposed expansion model solutions are very stable and competitive in performance compared to scenario tree approaches. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 47–70, 2016 相似文献
49.
为了实现对自行火炮传动系统的预测维修,以行星转向机为例,运用动态模糊综合评判的办法,提取引起行星转向机典型故障的关键影响因素,探讨了动态模糊判断矩阵和动态权重的确定方法,在此基础上确定了其动态预测模型,并用实例验证了模型的正确性。 相似文献
50.
装备的战场损伤、损耗预测是作战保障的基础。文中构建了导弹装备损伤预测的马尔可夫Markov模型,导弹装备战场损伤部件数量动力学预测模型,并针对战场损伤强度和维修强度对损伤概率和部件损伤数量进行了仿真。对导弹作战计划以及装备保障与维修计划的制定具有指导意义。 相似文献