共查询到19条相似文献,搜索用时 156 毫秒
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一个具有随机丢弃分组机制的GI/M/1/N排队系统 总被引:3,自引:0,他引:3
由于标准GI/M/1/N排队系统仅当等待队列中没有空闲位置时才丢弃到达的分组,不适合为QoS控制中的缓存队列管理建模。利用随机过程中输入流稀疏化的方法,在标准的GI/M/1/N排队系统中嵌入随机丢弃分组的机制,建立了一个具有随机丢弃分组机制的扩充的GI/M/1/N排队系统,以及该排队系统的分组丢失率、系统利用率、队列长度的均值/方差、平均等待时间等性能评价指标。 相似文献
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自相似网络流量建模及分析 总被引:5,自引:3,他引:2
利用RMD方法生成了自相似分形FGN流量,并分别利用R/S分析法、时间方差分析法和小波功率谱密度分析法估计自相似流量的Hurst参数.然后,利用OPNET仿真软件对传统的排队模型M/M/1和自相似下的排队模型的平均排队延时和平均队列长度进行了网络仿真,从而得出自相似对排队性能的影响. 相似文献
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通过对于标准的多服务台队列M/M/n模型的负荷过程的高负荷极限的证明来解释鞅定理,该系统为泊松到达,指数服务。通过对所考虑的负荷过程进行流体刻画,并且使用鞅方法来证明多服务台队列M/M/n模型的负荷过程的高负荷极限,并得到所考虑的负荷过程收敛的结论。在高负荷条件下使用Matlab编程对此过程进行仿真模拟,模拟仿真以产生随机数的方式来进行计算,为今后排队论中证明随机过程(比如等待时间,流失过程,放弃过程等)的收敛提供了新的方法。 相似文献
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多服务台混合制排队模型M/G/s/K的仿真研究 总被引:1,自引:1,他引:0
为更快、更方便地得到一般服务时间的多服务台混合制中M/G/s/K排队系统在达到稳定之后的系统状态,通过离散化处理仿真时间方法,并借鉴时间步长法的思想,给出一种基于Matlab编程的仿真算法。通过实验说明了该方法的有效性。对于处理此类排队问题提供了一个新的方法。 相似文献
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段金友 《信息技术与信息化》2014,(6):146-147
有限的资源和随机的需求是排队论存在的基础,而在如今的社会,这种现象越发广泛和复杂。我们将要求服务的顾客和提供服务的机构组合成一个系统,称之为排队系统。这种系统存在于各个方面,本文研究的是排队论运用在通信网络中的各端业务问题。排队论系统分为优先制排队系统和非优先制排队系统,本文描述了带有非强占权优先制的排队系统,其模型为两队中其中一对带有优先制度的M/M/1的模型。根据此模型可以定义变量,画出状态转移图并列出状态方程,最后求出稳态解。通过性能分析发现,带有优先权的M/M/1模型系统与一般模型相比性能将会有所提高,这也是优先制度的体现。 相似文献
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在通信网互连中,若被连子网具有不同的最大允许分组长度,那么有信关中一个较长的分组就可能要被拆分为多个较小的分组,这就是公组再分问题,已经证明,在某些情况下。再分后的公组流可以用一个修正的开关泊松过程来,本文RSPP和RSPP/M/1排队。文中推导出了RSPP到达间隔分布的表达式,并给出了平均到达率。文中还给出了队长分布,平均等候时间的表达式;信关输出流的特性对于全网的性能分析是必需的,因此本文着重 相似文献
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We present the analysis of an M/G/1/N queueing system with vacations under a dynamic time-limited service policy. This method is used to develop a procedure for performance analysis of a fiber distributed data interface (FDDI) network serving buffer-limited stations under asynchronous service. An efficient iteration procedure is employed to evaluate the limiting state distribution of the embedded Markov chain representing the system state process. Using supplementary variables and sample biasing techniques, we derive the queue size distribution at an arbitrary instant of time as well as the packet blocking probability and the mean packet delay. By exploiting the subtle structure of conditional supplementary variables and the recursive property of the conditional residual delay, the Laplace-Stieltjes transform of the packet delay distribution and a time-domain approximation of the packet delay distribution are obtained. For the analysis of a heterogeneous multi-station FDDI network, an iterative procedure which uses repeatedly the M/G/1/N vacation model described above is presented. This procedure provides for a numerically efficient analysis method by employing constructions of the approximate vacation time distributions. We illustrate the application of our analytical techniques to both symmetric and nonsymmetric FDDI network systems 相似文献
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《IEEE transactions on information theory / Professional Technical Group on Information Theory》2008,54(9):4107-4118
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We consider the ordinary M/M/1 queue with the FIFO queueing discipline. It seems that the sum of service times of the customers in the system (or the required work, as we call it briefly) is a random variable that is not considered before. In this paper we derive the equilibrium distribution of this variable. The task is not quite trivial because of the dependencies between the elapsed service time and the number of customers in the system. Our motivation for this problem comes from the performance analysis of a dynamic memory allocation scheme of a packet buffer. 相似文献
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We consider the fundamental delay bounds for scheduling packets In an N times N packet switch operating under the crossbar constraint. Algorithms that make scheduling decisions without considering queue backlog are shown to incur an average delay of at least O(N). We then prove that O(log(N)) delay is achievable with a simple frame based algorithm that uses queue backlog information. This is the best known delay bound for packet switches, and is the first analytical proof that sublinear delay is achievable in a packet switch with random inputs. 相似文献
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Mohsin Iftikhar Hassan Mathkour Muhammad Imran Abdullah Bedaiwi Athanasios V. Vasilakos 《Wireless Networks》2016,22(4):1269-1284
Provisioning guaranteed Quality of Service (QoS) in multiservice wireless internet is challenging due to diverse nature of end-user traffic (e.g., voice, streaming video, interactive gaming) passing through heterogeneous interconnected domains with their own policies and procedures. Numerous studies have shown that multimedia traffic carried in wireless internet possesses self-similar and long-range dependent characteristics. Nonetheless, published work on wireless traffic modeling is merely based on traditional Poisson traffic distribution which fails to capture these characteristics and hence yield misleading results. Moreover, existing work related to self-similar traffic modeling is primarily based on conventional queuing and scheduling combinations which are simple approximations.This paper presents a novel analytical framework for G/M/1 queuing system based on realistic internet traffic distribution to provide guaranteed QoS. We analyze the behavior of multiple classes of self-similar traffic based on newly proposed scheduling-cum-polling mechanism (i.e., combination of priority scheduling and limited service polling model). We formulate the Markov chain for G/M/1 queuing system and present closed form expressions for different QoS parameters i.e., packet delay, packet loss rate, bandwidth, jitter and queue length. We develop a customized discrete event simulator to validate the performance of the proposed analytical framework. The proposed framework can help in building comprehensive service level agreements for heterogeneous wireless domains. 相似文献
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Analysis of mean packet delay for upstream transmissions in passive optical networks with sleep mode
The sleep mode has been introduced to improve the energy efficiency of passive optical networks (PONs) with interleaved polling with adaptive cycle time (IPACT) as a medium access control (MAC) scheme. For energy saving, the sleep mode of each optical network unit (ONU) is activated based on the packet queue length for upstream traffic. We model such a PON as an N-user M/G/1 queue with reservations and vacations. Based on the framework of M/G/1 queueing analysis with some modification made to incorporate the nature of IPACT as well as the sleep mode, we derive a closed form expression of the mean packet delay. A unique challenge in our analysis is that certain quantities such as the residual time of an on-going sleep period for the upstream channel must be considered from the network's viewpoint while the delay due to the sleep mode experienced by a packet must be considered from the ONU's viewpoint. Simulation experiments are conducted to validate the analytical results and to show that the results are relatively insensitive to packet arrival statistics for large sleep periods. Finally, we demonstrate how a sleep period can be chosen given the quality-of-service (QoS) requirement on the mean packet delay. 相似文献
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Zhang J. Coyle E.J. Jr. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1991,37(6):1690-1696
The transient behavior of time-dependent M/M/1 queues is studied. The boundary probability function π0(t ), which is the probability that the queue is empty at time t , is shown with analyticity arguments to satisfy a Volterra-type integral equation. The boundary integral equation is derived, and a numerical algorithm is used to solve the integral equation and to find the expected queue size from π0(t ). The approach can be applied to many other types of time-dependent queues. Examples are given 相似文献