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带有可变备运期和有限服务率的经济批量模型 总被引:1,自引:0,他引:1
本文将备运期(Lead time)作为决定变量,在指数备运时间-费用函数的假定下,建立了服务率为有限的库存系统的最优经济批量模型,提供了寻求最佳备运期、最优订货周期及最优订货批量的简单方法,并给出了参数的灵敏度分析和应用实例。 相似文献
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人民币汇率、汇率风险对中国对美国出口的经济影响分析 总被引:1,自引:0,他引:1
汇率影响出口有两个途径,一是汇率变动(升值或贬值),二是汇率波动(汇率风险).2003年以来,中国一直面临人民币升值的压力,特别是来自美国和日本对人民币重新估值的压力;人民币汇率升值是否对出口产生负面效应,影响程度有多大,一直是这段时期的关注焦点.本文利用1990.01-2007.08间的月度数据主要从时间序列数据的季节效应分解(UCM)、自回归建模(自回归-GARCH)和动态条件相关系数(DCC)三个角度实证的分析了人民币汇率升值对中国对美国出口的经济影响,几个不同的角度,都揭示了人民币汇率升值会减少中国对美国的出口;本文还发现汇率风险的增加会减少出口贸易的增速.通过动态条件相关系数分析发现实际汇率对出口的解释能力为20%-30%;通过汇率对出口的弹性分析发现人民币月度汇率弹性为150~220(亿元/人民币兑美元);此外,近两年实际汇率升值起点滞后名义汇率升值起点1年左右,而中国对美国的出口又滞后实际汇率的升值起点3-4个月.最后,本文指出通过有效地抑制通货膨胀,降低美元储备,转移汇率风险等途径在一定程度上可缓解人民币汇率升值压力和对冲汇率风险. 相似文献
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Vinod Sharma 《Queueing Systems》2001,39(4):303-315
We consider a single queue with a Markov modulated Poisson arrival process. Its service rate is controlled by a scheduler. The scheduler receives the workload information from the queue after a delay. This queue models the buffer in an earth station in a satellite network where the scheduler resides in the satellite. We obtain the conditions for stability, rates of convergence to the stationary distribution and the finiteness of the stationary moments. Next we extend these results to the system where the scheduler schedules the service rate among several competing queues based on delayed information about the workloads in the different queues. 相似文献
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经济发展系统中的积累率的辨识问题 总被引:1,自引:1,他引:0
讨论了一类非定常经济系统的积累率的辨识问题,利用Banach空间中的Banach-Saks-Mazur定理,对极小化序列中的弱收敛序列,构造强收敛极小化序列,从而得到了辨识问题解的存在唯一性. 相似文献
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讨论了一类非定常非线性经济发展方程的积累率的辨识问题,利用Banach空间理论得到了辨识问题解的存在唯一性. 相似文献
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The classical economic production lot size (EPL) model assumes a constant production rate that is predetermined and inflexible, and perfect quality. Recent models have removed the assumption of perfect quality while maintaining the inflexible production rate assumption. Production rates in many cases, such as orders filled by a machine, can be changed. Moreover, unit production cost and process quality depend on the production rate. In this paper, we extend the EPL model to cases where the production rate is a decision variable. Unit production cost becomes a function of the production rate. Also, the quality of the production process deteriorates with increased production rate. We solve the proposed model for special cost and quality functions and illustrate the results with a numerical example. The results show that, for cases where increases in the production rate lead to a significant deterioration in quality, the optimal production rate may be smaller than the rate that minimizes unit production cost. For cases where quality is largely independent of the production rate, the optimal production rate may be larger than the rate that minimizes unit production cost. 相似文献
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In this paper, we study the inventory model for defective items with trapezoidal type demand rate. This paper develops a model to determine the optimal product reliability and production rate that achieves the biggest total integrated profit for an imperfect manufacturing process and necessary and sufficient conditions for optimality of the dynamic variables are given. The Euler–Lagrange method is used to obtain optimal solutions for product reliability parameter and dynamic production rate. Finally, numerical examples are presented to illustrate the proposed model. Suggestions for further research are provided. 相似文献
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彭江艳 《数学的实践与认识》2005,35(9):105-108
由于条件失效率有很好的直观意义且易获得,用它们去刻画相关部件组成的串或并联的系统失效率是一条有效的新途径.但并联系统失效率的表示过于复杂.由此,新定义过程失效率向量,但仍基于条件失效率,从另一方面描述并联系统的整个失效状况,并用Basu定义二维失效率说明其应用.最后,将以上两种刻画方式统一为系统过程失效率函数. 相似文献
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我国服务业结构与经济增长的实证研究 总被引:1,自引:0,他引:1
服务业的发展水平是衡量生产社会化程度和市场经济的重要标志,将服务业分为现代服务业和传统服务业,基于1978-2007年的统计数据,采用协整关系检验和格兰杰因果关系检验对服务业结构与经济增长关系进行实证分析.结果表明现代服务业、传统服务业和经济增长之间存在长期稳定的关系,但服务业内部结构发展不平衡,并对服务业结构的调整提出政策建议. 相似文献
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Journal of the Operational Research Society - 相似文献
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E. Omey 《Journal of Mathematical Sciences》2001,106(1):2732-2738
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