共查询到17条相似文献,搜索用时 437 毫秒
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本文通过对系统中顾客数设置门限N,考虑研究了服务台的服务速度依门限发生变化且当服务台未服务顾客(休假或故障)时到达顾客仅以概牢p进入系统的多重休假可修M/G(M/G)/1排队系统。通过L-变换、母函数以及补充变量方法得到了队长分布的瞬态解、稳态解及一些可靠性结果,并指出当两个服务速度相等时该模型与前人研究的M/G/1(E,MV)排队一致。 相似文献
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本文研究带有阈值控制策略的M/M/1多重休假排队模型.当一次服务结束时,根据系统中顾客数的不同,服务台可能进入普通休假,也可能进入工作休假或进入正规忙期.对该模型,应用拟生灭(QBD)过程和矩阵几何解的方法,我们得到了平稳队长的具体形式.在此基础上,我们进一步给出了平稳队长和平稳等待时间的条件随机分解结果、附加队长的概率母函数(PGF)以及附加延迟的Laplace-Stieltjes变换(LST)的具体形式. 相似文献
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本文研究休假时间服从T-SPH分布的M/M/1单重休假排队模型.T-SPH表示由可数状态生灭过程定义的位相型分布.该模型可以用一个具有可数位相的拟生灭(QBD)过程来描述.利用拟生灭过程和算子几何解的方法,我们给出了模型率算子的具体形式以及平稳队长分布的概率母函数.在此基础上,得到了平稳队长和平稳等待时间的随机分解结果... 相似文献
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在过去的二十年里,休假排队系统已经得到了广泛的研究.在各种休假排队模型中,在休假期内服务台是完全停止为顾客服务的.为了更客观地反映现实情况,本文在单重休假GI/M/1排队系统的基础上引入了在休假时服务台仍可低速服务而不是完全停止服务的工作休假策略和启动时间策略.对此模型的分析,我们重点关注顾客到达前夕时刻系统的状态,运用矩阵几何解方法得到了该系统的状态转移概率矩阵,并以概率矩阵为基础求出了系统的稳态平均队长和顾客的平均等待时间. 相似文献
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一、常态M/R、M/C和M/L绝对测定的成果
笔者建立了同轴导线绕组的互感线圈(Coaxial Winding Mutual Inductance Coil),如图1(a)所示。 相似文献
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M. C. T. van de Coevering 《OR Spectrum》1995,17(1):19-22
A practically important problem is the computation of transient performance measures for the M/M/1 queue. Trigonometric integral representations are very well suited for that purpose. This paper reviews a number of results that can be found scattered in the literature and also provides the practitioner simple recommendations for calculating routinely the M/M/1 performance measures. 相似文献
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本文研究了顾客批量到达且服务台忙时与闲时故障率不同的多服务台可修排队系统,推导出了系统的稳态平衡方程以及稳态概率值的求解思路.由于N≥2时手工计算的复杂性,使用Mathematica软件编程实现了稳态概率值的求取,并最终得到了系统有效服务台数的稳态分布、稳态队长的母函数以及平均队长等重要的系统指标. 相似文献
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Simulation modeling has been widely used to analyze complex stochastic systems, such as, to compute some performance measures of a modem manufacturing facility. Often, we are interested in optimizing these performance measures of the system wth respect to some controllable parameters. Traditional methods to find an optimum of a sirnulation model usually require making a number of simulation runs, which can be computationally intensive. This study proposes a stochastic optimization method to optimize a simulation model in a single simulation run, with the potential of large savings in computational effort. Two algorithms based on this method are developed and evaluated empirically using an M/M/l queue problem. Experimental results show that the algorithms, especially one of them, are promising and that this approach merits further investigation 相似文献
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The concept of more maintenance effort (or training) implying higher system reliability (or efficiency) is well accepted. In this paper we study an optimal maintenance (training) program based on this concept for a simple production system using the M/G/l vacation queue model. We discuss how to determine the optimal maintenance (training) time to minimize the average time spent by a job in the system. 相似文献
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Chiahon Chien 《IIE Transactions》1998,30(3):267-272
Conventional wisdom suggests that a fast single-server queue is preferable to a number of slower single-server queues. The rationale is that if the service rate of the superposed queue is the sum of the service rates of the individual queues, then the average waiting time for the superposed queue is smaller than the weighted average waiting time of the individual queues. This argument, however, assumes that the service time of the customers is perfectly scalable. Unfortunately, this assumption rarely holds in reality. In this paper we analyze the superposition of M/G/1 queues. We assume that there are scalable and unscalable components in the service time. On the basis of the criteria of average waiting time and average response time, we derive necessary and sufficient conditions for whether the superposition of queues is preferable. Examples of magnetic rotational disks are given to illustrate our findings. 相似文献
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本文主要研究服务员单重休假且在休假时间中根据 Min($N,D,V$)--控制策略可立即中断休假的 $M/G/1$ 排队系统.运用全概率分解技术和拉普拉斯变换工具,讨论在任意初始状态条件下队长的瞬态和稳态性质,得到了队长分布瞬态解的拉普拉斯变换表达式.在此基础上,直接获得了便于作数值计算的队长分布稳态解的递推表达式.进一步,给出了稳态队长的随机分解结构、附加队长分布的显示表达式,以及在一些特殊情形下的相应结果.最后,通过数值实例考察了附加队长分布对系统参数的敏感性,分析参数不同取值对系统运行性能的影响. 相似文献