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基于PME重尾分布服务时间的M/G/1模型排队性能研究 总被引:1,自引:0,他引:1
通信网络的业务源普遍存在着白相似性(或称为长相关性),传统的假定业务到达间隔服从负指数分布的Poisson模型或其改进形式已不再适用.但在利用M/G/1模型对白相似业务源进行排队分析时,由于重尾分布服务时间的LST变换无闭合形式,进行排队性能分析非常困难.该文通过引入一类混合指数分布证明此类分布服从Pareto重尾分布,并得到相应的LST变换闭合形式及服务时间渐进级数,同时将形状参数y=3/2时的服务时间及其LST变换推广到更一般的情形,从而较为有效地解决了重尾分布的信源排队等待时间分析问题. 相似文献
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In this article, we consider an infinite capacity N-policy M/G/1 queueing system with a single removable server. Poisson arrivals and general distribution service times are assumed. The server is controllable that may be turned on at arrival epochs or off at service completion epochs. We apply a differential technique to study system sensitivity, which examines the effect of different system input parameters on the system. A cost model for infinite capacity queueing system under steady-state condition is developed, to determine the optimal management policy at minimum cost. Analytical results for sensitivity analysis are derived. We also provide extensive numerical computations to illustrate the analytical sensitivity properties obtained. Finally, an application example is presented to demonstrate how the model could be used in real applications to obtain the optimal management policy. 相似文献
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In this paper a performance analysis of the CRMA (Cyclic Reservation Multiple Access) medium access protocol, which is proposed as an access mechanism for high-speed LANs and MANs is presented. An approximate computational method is derived to obtain the distribution functions of performance measures of interest like the medium access delay and the packet transfer time. The analysis is done in discrete-time domain using a decomposition approach for the access delay in conjunction with a G/G/1 queue with control-feedback and a M/G/1 queue with server vacation. In the model the reservation-cancelation backpressure mechanism is also taken into account. Numerical results are obtained to investigate the efficiency of the backpressure scheme and the scaling issues of the interreserve interval under various load conditions and system configurations. Furthermore, results addressing performance aspects like the fairness issues, the jitter of maximum access delay and the system behavior under station-wise saturated conditions are also discussed. 相似文献
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Jeongsim KimAuthor VitaeBara KimAuthor Vitae 《Performance Evaluation》2011,68(3):256-270
We consider an M/G/1 queue with different classes of customers and discriminatory random order service (DROS) discipline. The DROS discipline generalizes the random order service (ROS) discipline: when the server selects a customer to serve, all customers waiting in the system have the same selection probability under ROS discipline, whereas customers belonging to different classes may have different selection probabilities under DROS discipline. For the M/G/1 queue with DROS discipline, we derive equations for the joint queue length distributions and for the waiting time distributions of each class. We also obtain the moments of the queue lengths and the waiting time of each class. Numerical results are given to illustrate our results. 相似文献
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In this paper we present an exact steady-state analysis of a discrete-time Geo/G/1 queueing system with working vacations, where the server can keep on working, but at a slower speed during the vacation period. The transition probability matrix describing this queuing model can be seen as an M/G/1-type matrix form. This allows us to derive the probability generating function (PGF) of the stationary queue length at the departure epochs by the M/G/1-type matrix analytic approach. To understand the stationary queue length better, by applying the stochastic decomposition theory of the standard M/G/1 queue with general vacations, another equivalent expression for the PGF is derived. We also show the different cases of the customer waiting to obtain the PGF of the waiting time, and the normal busy period and busy cycle analysis is provided. Finally, we discuss various performance measures and numerical results, and an application to network scheduling in the wavelength division-multiplexed (WDM) system illustrates the benefit of this model in real problems. 相似文献
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The queue of a single server is considered with independent and identically distributed interarrivai and service times and an infinite (GI/G/1) or finite (GI/G/1/N) waiting room. The queue discipline is non-preemptive and independent of the service times.
A discrete time version of the system is analyzed, using a two-component state model at the arrival and departure instants of customers. The equilibrium equations are solved by a polynomial factorization method. The steady state distribution of the queue size is then represented as a linear combination of geometrical series, whose parameters are evaluated by closed formulae depending on the roots of a characteristic polynomial.
Considering modified boundary constraints, systems with finite waiting room or with an exceptional first service in each busy period are included. 相似文献
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随着云计算技术的广泛使用,如何对采用虚拟化技术的云计算服务器的性能进行有效管理,是云计算研究的热点问题之一.论文提出了一种基于自适应控制理论的动态资源控制策略(DRC),该控制策略在保证服务级别协议的前提下,对运行在服务器上的各个虚拟机进行优化配置,使服务器的硬件资源得到最大化的利用.同时设计了一种新型的自适应线性二次高斯控制器,来应对具有Web应用所面对的动态负载.在基于Xen技术搭建的实验平台上,对服务器的性能在不同工作负载的情况下进行了测试,并与未采用DRC策略的服务器性能进行了对比.实验结果表明,在动态工作负载下,与为采用DRC策略的服务器相比,DRC控制策略能够有效保证不同Web应用的响应时间稳定在设定的参考值. 相似文献
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针对IEEE 802.15.4时隙载波侦听多址接入与碰撞避免(CSMA/CA)算法,利用二维Markov链分析方法提出了一个网络分析模型。该模型特别考虑了IEEE 802.15.4协议的休眠模式以及退避窗口先于退避阶数(NB)达到最大值的情况。在此基础上,结合M/G/1/K排队理论推导得到了吞吐量的表达式,进而分析了网络在非饱和状态下数据包到达率对吞吐量的影响,利用模拟平台NS2进行了仿真。实验结果显示理论分析结果与仿真结果可以较好地拟合,并能准确描述网络吞吐量的变化,验证了分析模型的有效性。 相似文献
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Kuo-Hsiung Wang & Jau-Chuan Ke 《International Transactions in Operational Research》2002,9(2):195-212
This paper considers a single non-reliable server in the ordinary M/G/1 queueing system whose arrivals form a Poisson process and service times are generally distributed. We also study a single removable and non-reliable server in the controllable M/G/1 queueing systems operating under the N policy, the T policy and the Min( N , T ) policy. It is assumed that the server breaks down according to a Poisson process and the repair time has a general distribution. In three control policies, we show that the probability that the server is busy in the steady-state is equal to the traffic intensity. It is shown that the optimal N policy and the optimal Min( N , T ) policy are always superior to the optimal T policy. Sensitivity analysis is also investigated. 相似文献
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探讨了基于Internet网络,采用终端字符方式的SSH、C/S结构下的VNC以及B/S结构下的Webmin三种模式,远程控制Linux操作系统服务器的管理方法,并对这三种模式方法的适用特点、资源优势和安全机制等性能进行了分析。 相似文献
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该文提出了实时Client/Server数据库系统多版本两阶段封锁并发控制协议和有效的恢复机制。协议区分只读事务和更新事务。只读事务在执行读操作时遵从多版本时间排序协议,更新事务执行强两阶段封锁协议,即持有全部锁直到事务结束。只读事务读请求从不失败,不必等待等特性。在典型数据库系统中,读操作比写操作频繁。这个特性对于实践来说至关重要。为了提高只读事务的响应时间,协议让每个客户端与一个一致数据库影子相联,只读事务在客户端处理。更新事务提交到服务端运行。服务端每个事务Ti在提交时系统必须向所有客户端广播信息。客户端根据得到的广播信息自动构造一致数据库影子。一致数据库影子还将用于系统恢复。通过仿真模拟。与2V2PL和OCC-TI-WAIT-50协议进行比较,结果表明:该并发控制协议不仅能有效降低事务延误截止时间率和重起动率,而且能改善只读事务的响应时间,减少优先级高事务的锁等待时间。协议性能优于2V2PL协议和OCC-TI-WAIT-50协议。 相似文献
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文中提出了一种构造具有简单结点的B样条曲面G1/G2光滑拼接的方法。本方法根据B样条曲面达到拼接的条件,经过对原曲面和待拼接曲面的偏导曲线进行离散化处理和结点调整,将其转化为Bézier的表示方式。根据Bézier的拼接条件,获得B样条曲面间控制点的关系。最终实现B样条曲面G1/G2的光滑拼接。 相似文献
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We study an M/G/1 queueing system with a server that can be switched on and off. The server can take a vacation time T after the system becomes empty. In this paper, we investigate a randomized policy to control a server with which, when the system is empty, the server can be switched off with probability p and take a vacation or left on with probability (1 − p) and continue to serve the arriving customers. For this system, we consider the operating cost and the holding cost where the operating cost consists of the system running and switching costs (start up and shut down costs). We describe the structure and characteristics of this policy and solve a constrained problem to minimize the average operating cost per unit time under the constraint for the holding cost per unit time. 相似文献
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In this paper, the matrix-analytic approach is applied to explore the per-stream loss behavior of the multimedia traffic under RED scheme. We constructed a ∑MAP/M/1/K queuing model for the RED mechanism with multimedia traffic which follows a continuous-time Markovian arrival process (MAP). In addition to evaluating the long-term per-stream packet drop probabilities, we examine the bursty nature of per-stream packet drops by means of conditional statistics with respect to dropped periods and the probability that the queuing system stays in the dropped period. The dropped period corresponds to having more than a certain number of packets in router buffer; non-dropped period corresponds to the opposite. These performance measures describe the quality of service provided by the router to particular multimedia traffic streams in the presence of background multimedia traffic. 相似文献
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