Pooling,unpooling/specialization,and discretionary task completion are typical operational strategies in queueing systems that arise in healthcare,call centers,and online sales.These strategies may have advantages and...Pooling,unpooling/specialization,and discretionary task completion are typical operational strategies in queueing systems that arise in healthcare,call centers,and online sales.These strategies may have advantages and disadvantages in different operational environments.This paper uses the M/M/1 and M/M/2 queues to study the impact of pooling,specialization,and discretionary task completion on the average queue length.Closed-form solutions for the average M/M/2 queue length are derived.Computational examples illustrate how the average queue length changes with the strength of pooling,specialization,and discretionary task completion.Finally,several conjectures are made in the paper.展开更多
This paper considers an efficient priority service model with two-level-polling scheme which the message packets conform to the discrete-time Geom/G/1 queue with multiple vacations and bulk arrival. By the embedded Ma...This paper considers an efficient priority service model with two-level-polling scheme which the message packets conform to the discrete-time Geom/G/1 queue with multiple vacations and bulk arrival. By the embedded Markov chain theory and the probability generating function method, we set up the mathematics functions and give closed form expressions for obtaining the mean cyclic period （MCP）, the mean queue length （MQL） and the mean waiting time （MWT） characteristics, the analytical results are also verified through extensive computer simulations. The performance analysis reveals that this priority polling scheme can gives better efficiency as well as impartiality in terms of system characteristics, and it can be used for differentiating priority service to guarantee better QoS and system stability in design and improvement of MAC protocol.展开更多
The wireless mesh networks trathc are of selt：snmlarlty and the network pertOrmance is degraded by seltsimillar traffic. Network coding is a new technology which improves network performance. An algorithm is presente...The wireless mesh networks trathc are of selt：snmlarlty and the network pertOrmance is degraded by seltsimillar traffic. Network coding is a new technology which improves network performance. An algorithm is presented that it uses network coding to reduce queue length and delay time when self-similar traffic occurs. Based on synchronization, data packets are classified by destination address and lengths. Simulation results show that with the proposed synchronization techniques, network coding, even in scenarios with burst self-similar traffic, where network coding could not have been deployed so far, increases throughput and lowers packet loss in wireless mesh networks.展开更多
With results on the infinite servers queue systems with Poisson arrivals - M｜G｜∞ queues - busy period, it is displayed an application of those queue systems in the unemployment periods time length parameters and di...With results on the infinite servers queue systems with Poisson arrivals - M｜G｜∞ queues - busy period, it is displayed an application of those queue systems in the unemployment periods time length parameters and distribution function study. These queue systems are adequate to the study of many population processes, and this quality is brought in here. The results presented are mainly on unemployment periods length and their number in a certain time interval. Also, some questions regarding the practical applications of the outlined formulas are briefly discussed.展开更多
This paper considers a discrete-time Geo/G/1 queue under the Min（N, D）-policy in which the idle server resumes its service if either N customers accumulate in the system or the total backlog of the service times of ...This paper considers a discrete-time Geo/G/1 queue under the Min（N, D）-policy in which the idle server resumes its service if either N customers accumulate in the system or the total backlog of the service times of the waiting customers exceeds D, whichever occurs first （Min（N, D）-policy）. By using renewal process theory and total probability decomposition technique, the authors study the transient and equilibrium properties of the queue length from the beginning of the arbitrary initial state, and obtain both the recursive expression of the z-transformation of tile transient queue length distribution and the recursive formula for calculating the steady state queue length at arbitrary time epoch n＋. Meanwhile, the authors obtain the explicit expressions of the additional queue length distribution, l^trthermore, the important relations between the steady state queue length distributions at different time epochs n , n and n＋ are also reported. Finally, the authors give numerical examples to illustrate the effect of system parameters on the steady state queue length distribution, and also show from numerical results that the expressions of the steady state queue length distribution is important in the system capacity design.展开更多
This paper considers a discrete-time queue with N-policy and LAS-DA(late arrival system with delayed access) discipline.By using renewal process theory and probability decomposition techniques,the authors derive the r...This paper considers a discrete-time queue with N-policy and LAS-DA(late arrival system with delayed access) discipline.By using renewal process theory and probability decomposition techniques,the authors derive the recursive expressions of the queue-length distributions at epochs n^-,n^+,and n.Furthermore,the authors obtain the stochastic decomposition of the queue length and the relations between the equilibrium distributions of the queue length at different epochs(n^-,n^+,n and departure epoch D_n).展开更多
文摘CICQ(Combined Input Crosspoint Queued)是一种在crossbar交叉点加入少量缓存的交换结构,具有无需内部加速比及分布并行调度的特性。为了自适应网络环境中各种业务流量,提高在非均匀流量下的性能,该文提出了一种基于最长队列预测的高效CICQ交换结构调度算法——RR-LQD(Round Robin with Longest Queue Detecting)。RR-LQD算法复杂度为O(1),具有良好的可扩展性;通过预测局部"最长"队列并尽力为其服务,保持调度中队列长度的均衡,能够适应各种非均匀流量的网络环境。仿真结果表明:在各种均匀和非均匀流量下,RR-LQD算法均能达到100%的吞吐量,并且具有优良的时延性能。该文使用FPGA芯片实现了RR-LQD算法仲裁器,能够满足高速、大容量交换结构的设计需要。
文摘Pooling,unpooling/specialization,and discretionary task completion are typical operational strategies in queueing systems that arise in healthcare,call centers,and online sales.These strategies may have advantages and disadvantages in different operational environments.This paper uses the M/M/1 and M/M/2 queues to study the impact of pooling,specialization,and discretionary task completion on the average queue length.Closed-form solutions for the average M/M/2 queue length are derived.Computational examples illustrate how the average queue length changes with the strength of pooling,specialization,and discretionary task completion.Finally,several conjectures are made in the paper.
基金Supported by the National Natural Science Foundation of China （No. 69862001, F0424104, 60362001 and 61072079）.
文摘This paper considers an efficient priority service model with two-level-polling scheme which the message packets conform to the discrete-time Geom/G/1 queue with multiple vacations and bulk arrival. By the embedded Markov chain theory and the probability generating function method, we set up the mathematics functions and give closed form expressions for obtaining the mean cyclic period （MCP）, the mean queue length （MQL） and the mean waiting time （MWT） characteristics, the analytical results are also verified through extensive computer simulations. The performance analysis reveals that this priority polling scheme can gives better efficiency as well as impartiality in terms of system characteristics, and it can be used for differentiating priority service to guarantee better QoS and system stability in design and improvement of MAC protocol.
基金Supported by the National Natural Science Foundation of China （60873082,61073186, 61073104, 60903058） China Postdoctoral Science Foundation （20090451108）the Science and Technology Planning Project of Hunan Province （2011FJ3237）.
文摘The wireless mesh networks trathc are of selt：snmlarlty and the network pertOrmance is degraded by seltsimillar traffic. Network coding is a new technology which improves network performance. An algorithm is presented that it uses network coding to reduce queue length and delay time when self-similar traffic occurs. Based on synchronization, data packets are classified by destination address and lengths. Simulation results show that with the proposed synchronization techniques, network coding, even in scenarios with burst self-similar traffic, where network coding could not have been deployed so far, increases throughput and lowers packet loss in wireless mesh networks.
文摘With results on the infinite servers queue systems with Poisson arrivals - M｜G｜∞ queues - busy period, it is displayed an application of those queue systems in the unemployment periods time length parameters and distribution function study. These queue systems are adequate to the study of many population processes, and this quality is brought in here. The results presented are mainly on unemployment periods length and their number in a certain time interval. Also, some questions regarding the practical applications of the outlined formulas are briefly discussed.
基金supported by the National Natural Science Foundation of China under Grant Nos.71171138,71301111,71571127the Scientific Research Innovation&Application Foundation of Headmaster of Hexi University under Grant Nos.XZ2013-06,XZ2013-09
文摘This paper considers a discrete-time Geo/G/1 queue under the Min（N, D）-policy in which the idle server resumes its service if either N customers accumulate in the system or the total backlog of the service times of the waiting customers exceeds D, whichever occurs first （Min（N, D）-policy）. By using renewal process theory and total probability decomposition technique, the authors study the transient and equilibrium properties of the queue length from the beginning of the arbitrary initial state, and obtain both the recursive expression of the z-transformation of tile transient queue length distribution and the recursive formula for calculating the steady state queue length at arbitrary time epoch n＋. Meanwhile, the authors obtain the explicit expressions of the additional queue length distribution, l^trthermore, the important relations between the steady state queue length distributions at different time epochs n , n and n＋ are also reported. Finally, the authors give numerical examples to illustrate the effect of system parameters on the steady state queue length distribution, and also show from numerical results that the expressions of the steady state queue length distribution is important in the system capacity design.
基金supported by the National Natural Science Foundation of China under Grant No.70871084The Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No. 200806360001a grant from the "project 211(PhaseⅢ)" of the Southwestern University of Finance and Economics, Scientific Research Fund of Southwestern University of Finance and Economics
文摘This paper considers a discrete-time queue with N-policy and LAS-DA(late arrival system with delayed access) discipline.By using renewal process theory and probability decomposition techniques,the authors derive the recursive expressions of the queue-length distributions at epochs n^-,n^+,and n.Furthermore,the authors obtain the stochastic decomposition of the queue length and the relations between the equilibrium distributions of the queue length at different epochs(n^-,n^+,n and departure epoch D_n).
