共查询到19条相似文献,搜索用时 109 毫秒
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针对分布式多媒体系统中不同媒体流的同步问题,建立了具有休假特征离散时间随机匹配的双输入排队模型Geom_1+Geom_2/Geom/1.利用矩阵几何解方法对该模型进行了详细的分析,给出了该排队系统的主要稳态性能指标:系统处在忙期的概率,两类媒体流分组的平均队长,系统处在分组不匹配状态的概率等结果.最后,通过数值例子说明了休假参数和匹配模式变化对系统性能指标的影响. 相似文献
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该文在M/M/c排队驱动系统中加入工作休假策略,研究了单重工作休假多服务台排队驱动的流体模型.利用拟生灭过程和矩阵几何解法得到驱动系统稳态队长分布.构建净输入率结构,导出流体模型的稳态联合分布函数满足的的矩阵微分方程组,进而利用Laplace-Stieltjes变换(LST)方法得到稳态下缓冲器库存量的空库概率及均值表达式.最后,给出模型在多信道无线Mesh网下的应用,通过数值例子展示参数变化对系统性能指标的影响. 相似文献
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研究了具有两阶段服务和服务台故障的M/M/1/N多重休假排队系统.利用马尔可夫过程理论建立了系统稳态概率方程组,并利用分块矩阵解法,得到了稳态概率的矩阵解.然后由此得出了系统的平均队长、平均等待队长等性能指标. 相似文献
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具有第二次可选服务的带反馈的N-策略Mx/G/1(E,MV)排队系统分析 总被引:1,自引:0,他引:1
研究N策略下的批量到达的具有第二次可选择服务且两次服务均可反馈的多重休假排队系统。建立了休假、反馈、可选服务多类型相结合的排队模型。本文采用补充变量法,首先建立了系统稳态下的状态转移方程,通过求解得到了稳态下系统队长的概率母函数,进而计算出稳态下系统的平均队长。对稳态队长进行分析之后,我们又给出了稳态队长的随机分解定理,其中给出了附加队长的明确概率解释。 相似文献
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该文研究两个修理工的M/M/2可修排队系统, 系统有两个相同的服务台, 服务台忙时与闲时故障率不同. 文中给出系统的稳态状态概率, 系统的稳态可用度及系统的稳态平均队长, 并给出系统稳态概率存在的条件. 相似文献
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研究批量到达带反馈的多重休假M/G/1排队.建立休假,反馈,和成批到达的多类型相结合的排队模型.采用了嵌入马尔可夫链的方法研究了该排队系统,推导出稳态队长分布的母函数及其随机分解结果,给出忙期的LST和全假期的均值.最后考虑了批量等于1的特殊情况. 相似文献
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研究带有反馈的具有正、负两类顾客的Geom/Geom/1离散时间休假排队模型.休假排队策略为单重休假,其中负顾客不接受服务,只起一对一抵消队首正在接受服务的顾客作用.完成服务的正顾客以概率σ(0≤σ≤1)等待下次服务,以概率σ离开系统.运用拟生灭过程和矩阵几何解方法得到队长的稳态分布的存在条件和表达式,进而求出系统队长稳态分布的随机分解.此外,我们利用了数值例子进一步反映参数对平均队长的影响. 相似文献
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In this paper, we analyze a single-server vacation queue with a general arrival process. Two policies, working vacation and vacation interruption, are connected to model some practical problems. The GI/M/1 queue with such two policies is described and by the matrix analysis method, we obtain various performance measures such as mean queue length and waiting time. Finally, using some numerical examples, we present the parameter effect on the performance measures and establish the cost and profit functions to analyze the optimal service rate η during the vacation period. 相似文献
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When queueing models are used for performance analysis of some stochastic system, it is usually assumed that the system is in steady-state. Whether or not this is a realistic assumption depends on the speed at which the system tends to its steady-state. A characterization of this speed is known in the queueing literature as relaxation time.The discrete D/G/1 queue has a wide range of applications. We derive relaxation time asymptotics for the discrete D/G/1 queue in a purely analytical way, mostly relying on the saddle point method. We present a simple and useful approximate upper bound which is sharp in case the load on the system is not very high. A sharpening of this upper bound, which involves the complementary error function, is then developed and this covers both the cases of low and high loads.For the discrete D/G/1 queue, the stationary waiting time distribution can be expressed in terms of infinite series that follow from Spitzer’s identity. These series involve convolutions of the probability distribution of a discrete random variable, which makes them suitable for computation. For practical purposes, though, the infinite series should be truncated. The relaxation time asymptotics can be applied to determine an appropriate truncation level based on a sharp estimate of the error caused by truncating.This revised version was published online in June 2005 with corrected coverdate 相似文献
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本文研究了带有止步和中途退出的M^x/M/1/N多重休假排队系统。顾客成批到达,到达后每批中的顾客,或者以概率b决定进入队列等待服务,或者以概率1-b止步(不进入系统)。顾客进入系统后可能因为等待的不耐烦而在没有接受服务的情况下离开系统(中途退出)。系统中一旦没有顾客,服务员立即进行多重休假。首先,利用马尔科夫过程理论建立了系统稳态概率满足的方程组。其次,在利用高等代数相关知识证明了相关矩阵可逆性的基础上,利用矩阵解法求出了稳态概率的矩阵解,并得到了系统的平均队长、平均等待队长以及顾客的平均损失率等性能指标。 相似文献
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This paper deals with an MX/G/1 queueing system with a vacation period which comprises an idle period and a random setup period. The server is turned
off each time when the system becomes empty. At this point of time the idle period starts. As soon as a customer or a batch
of customers arrive, the setup of the service facility begins which is needed before starting each busy period. In this paper
we study the steady state behaviour of the queue size distributions at stationary (random) point of time and at departure
point of time. One of our findings is that the departure point queue size distribution is the convolution of the distributions
of three independent random variables. Also, we drive analytically explicit expressions for the system state probabilities
and some performance measures of this queueing system. Finally, we derive the probability generating function of the additional
queue size distribution due to the vacation period as the limiting behaviour of the MX/M/1 type queueing system.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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In this paper, we study a discrete time Geom/Geom/1 queue with multiple working vacations. Using the quasi birth and death chain and matrix-geometric solution method, we give distributions for the number of customers in system and the waiting time of a customer and their stochastic decomposition structures, and obtain distributions of the additional number of customers and additional delay. Furthermore, we derive the formulae of expected regular busy period and expected busy cycle. Finally, by numerical examples, we analyze the effect of the parameters on the expected queue length and sojourn time. 相似文献
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Shoji Kasahara Tetsuya Takine Yutaka Takahashi Toshiharu Hasegawa 《Queueing Systems》1993,14(3-4):349-367
Many researchers have studied variants of queueing systems with vacations. Most of them have dealt with M/G/1 systems and have explicitly analyzed some of their performance measures, such as queue length, waiting time, and so on. Recently, studies on queueing systems whose arrival processes are not Poissonian have appeared. We consider a single server queueing system with multiple vacations and E-limited service discipline, where messages arrive to the system according to a switched Poisson process. First, we consider the joint probability density functions of the queue length and the elapsed service time or the elapsed vacation time. We derive the equations for these pdf's, which include a finite number of unknown values. Using Rouché's theorem, we determine the values from boundary conditions. Finally, we derive the transform of the stationary queue length distribution explicitly. 相似文献
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研究了带有止步和中途退出的M~x/M/1/N单重工作休假排队系统.顾客成批到达,到达后每批中的顾客,或者以概率b决定进入队列等待服务,或者以概率1-b止步(不进入系统).顾客进入系统后可能因为等待的不耐烦而在没有接受服务的情况下离开系统(中途退出).系统中一旦没有顾客,服务员立即进入单重工作休假.首先,利用马尔科夫过程理论建立了系统稳态概率满足的方程组.其次利用矩阵解法求出了稳态概率的矩阵解并得到了系统的平均队长、平均等待队长以及顾客的平均消失概率等性能指标.最后通过数值例子分析了工作休假时的低服务率η和休假率θ这两个参数对系统平均队长的影响. 相似文献