共查询到19条相似文献,搜索用时 238 毫秒
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研究了一个修理工和c个服务台的可修排队系统.假设顾客的到达过程为PH更新过程,服务台在忙时与闲时具有不同的故障率.顾客的服务时间、服务台的寿命以及服务台的修理时间均服从指数分布.通过建立系统的拟生灭过程,得到了系统稳态分布存在的充要条件.利用矩阵几何解方法,给出了系统的稳态队长.在此基础上,得到了系统的某些排队论和可靠性指标. 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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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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王松建 《数学的实践与认识》2014,(20)
在PH/M/1排队模型中,引入了负顾客和Bernoulli反馈,并讨论了服务台容量为有限和无限两类模型,其中,模型一为服务台容量为无限的PH/M/1排队模型,利用拟生灭过程和矩阵几何解法得到了系统的转移速率矩阵,给出了系统正常返的充要条件,并得到了系统的稳态队长、忙期长度的拉普拉斯变换,以及系统的其它相关性能指标.模型二为服务台容量为有限的PH/M/1/N排队模型,同样使用拟生灭过程给出了马尔科夫过程的转移速率矩阵,并利用矩阵分析法进行求解,得到了该系统的稳态解和其它相关指标. 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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《数学的实践与认识》2017,(16)
在多服务台M/M/c排队系统中,引入半空竭服务的d型工作休假策略.当系统中有d个服务台空闲时,令d个空闲的服务台开始一次多重同步工作休假,休假期间的服务台继续慢速服务新到顾客,其余c-d个服务台正常工作.在工作休假期间,系统中顾客数小于等于c-d个时,一个顾客的离开是由正常工作速率服务台完成的.系统中顾客数多于c-d个时,一个服务的完成可能是接受了正常速率服务,也可能是接受了低速服务.利用拟生灭过程和矩阵几何解方法得到了稳态队长分布,给出模型在多层蜂窝系统(HCS)中的应用,并对影响系统性能指标的参数做出了数值分析. 相似文献
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研究了带有止步和中途退出的M/M/R/N同步多重工作休假排队系统,利用马尔可夫过程理论和矩阵解法求出了含有两个逆阵的系统稳态概率的矩阵解,并得到了系统的平均队长、服务员处在工作休假期的概率以及顾客的平均止步率等性能指标.最后通过数值例子分析了系统的参数对平均队长的影响. 相似文献
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研究了带有止步和中途退出的Mx/M/R/N同步休假排队系统.顾客成批到达.到达的顾客如果看到服务员正在休假或者全忙,他或者以概率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).系统根据一定的原则以概率nk在未止步的k个顾客中选择n个进入系统.在系统中排队等待服务的顾客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,R个服务员立即进行同步多重休假.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,在证明了相关矩阵可逆性的基础上,利用矩阵解法求出了系统稳态概率的明显表达式,并得到了系统的平均队长、平均等待队长及顾客的平均损失率等性能指标. 相似文献
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Boris Tsybakov 《Queueing Systems》2006,52(2):153-156
This note gives a solution for the problem of finding the probability density and probability distribution functions of the
N-busy-period length for the M/M/∞ system where the servers are not necessarily the same. A solution in case of the same servers
was done in [3].
AMS Subject Classification 60K25 68M20 相似文献
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We study a GI/M/c type queueing system with vacations in which all servers take vacations together when the system becomes empty. These servers keep taking synchronous vacations until they find waiting customers in the system at a vacation completion instant.The vacation time is a phase-type (PH) distributed random variable. Using embedded Markov chain modeling and the matrix geometric solution methods, we obtain explicit expressions for the stationary probability distributions of the queue length at arrivals and the waiting time. To compare the vacation model with the classical GI/M/c queue without vacations, we prove conditional stochastic decomposition properties for the queue length and the waiting time when all servers are busy. Our model is a generalization of several previous studies. 相似文献
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Tsung-Yin Wang Jau-Chuan Ke Kuo-Hsiung Wang Siu-Chuen Ho 《Mathematical Methods of Operations Research》2006,63(2):371-384
This paper studies maximum likelihood estimates as well as confidence intervals of an M/M/R queue with heterogeneous servers under steady-state conditions. We derive the maximum likelihood estimates of the mean arrival rate and the three unequal mean service rates for an M/M/3 queue with heterogeneous servers, and then extend the results to an M/M/R queue with heterogeneous servers. We also develop the confidence interval formula for the parameter ρ, the probability of empty system P
0, and the expected number of customers in the system E[N], of an M/M/R queue with heterogeneous servers 相似文献
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We consider the machine repair problem in which failed machines balk (do not enter) with a constant probability (1 – b) and renege (leave the queue after entering) according to a negative exponential distribution. A group of identical automatic machines are maintained by R servers which themselves are subject to breakdowns. Failure and service times of the machines, and breakdown and repair times of the servers, are assumed to follow a negative exponential distribution. Each server is subject to breakdown even if no failed machines are in the system. This paper presents a matrix geometric method for deriving the steady-state probabilities, using which various system performance measures that can be obtained. A cost model is developed to determine the optimum number of servers. The minimum expected cost, the optimal number of servers, and various system performance measures are provided based on assumed numerical values given to the system parameters. Also the sensitivity analysis is investigated. 相似文献
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D.F. Holman M.L. Chaudhry B.R.K. Kashyap 《European Journal of Operational Research》1983,13(2):142-145
In the present paper we consider the service system MX/G/∞ characterized by an infinite number of servers anda general service time distribution. The customers arrive at the system in groups of size X, which is a random variable, the time between group arrivals being exponentially distributed. Using simple probability arguments, we obtain probability generating functions (p.g.f.'s) of the number of busy servers at time t and the number that depart by time t. Several other properties of these random variables are also discussed. 相似文献
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利用有限状态拟生灭过程和全概率分解的方法,首次研究了只允许部分服务台同步多重休假的M/M/e/k排队系统,得到了稳态队长和等待时间分布,并且讨论了系统的优化问题. 相似文献