The M/G/1 queue with permanent customers

The authors examine an M/G/1 FCFS (first come, first served) queue with two types of customers: ordinary customers, who arrive according to a Poisson process, and permanent customers, who immediately return to the end of the queue after having received a service. The influence of the permanent customers on queue length and sojourn times of the Poisson customers is studied using results from queuing theory and from the theory of branching processes. In particular, it is shown that, when the service time distributions of the Poisson customers and all K permanent customers are negative exponential with identical means, the queue length and sojourn time distributions of the Poisson customers are the (K+1)-fold convolution of those for the case without permanent customers     

Recursive formulas for the moments of queue length in the BMAP/G/1 queue

We present recursive formulas for the moments of the joint distribution of the queue length and the state of the underlying process in the BMAP/G/1 at the service completion and arbitrary time epochs.     

Transient analysis of the MMPP/G/1/K queue

In this paper the transient behaviour of a finite-buffer queue fed by the Markov-modulated Poisson process is studied. The results include formulas for the transforms of transient queue size distribution, transient full buffer probability and transient delay (workload). Computational issues are discussed and numerical samples presented.This material is based upon work supported by the Polish Ministry of Scientific Research and Information Technology under Grant No. 3 T11C 014 26.     

Decay rate (ER) modelling of G/D/1 queue, and results for ATMtelecommunications

The authors present a new formula for calculating the decay rate in the queueing system G/D/1. This queueing model has potential for application in cell-based telecommunication systems, such as ATM, since it allows generally distributed inter-cell arrival times, while keeping the cell transmission time constant. The results presented here show that considerable improvements in accuracy are now available     

M θ/G/1/m and M θ/G/1 systems with the service time dependent on the queue length

The M ^θ/G/1/m and M ^θ/G/1 queueing systems, in which the service time depends on the queue length and is determined at the beginning of service of a customer, are investigated. The average busy period and the stationary distribution of the number of customers in the system have been found via the approach based on the idea of V.S. Korolyuk’s potential method. As a special case, the M ^θ/G/1 queue with a single threshold of switching of service modes is examined. The results are checked using the simulation model constructed with the use of GPSS World software tools.     

Mθ/G/1/m and Mθ/G/1 queues with operating parameters depending on the queue length

M^θ/G/1/m and M^θ/G/1 queues are considered in the case when the service time and input flow parameters depend on the queue length and are determined at the instants of completion of the service of customers. With the help of an approach based on the idea of Korolyuk’s potential method, the Laplace transforms are found for the distribution of the number of customers in a system within the busy period and for the distribution function of the busy period. The mean duration of the busy period and the stationary distribution of the number of customers in a system are determined. An M^θ/G/1 system with one threshold of functioning mode switching is considered as a particular case. The obtained results are verified with the help of simulation models developed with the use of the GPSS World tools.     

A batchSPP/G/1 queue with multiple vacations and exhaustive service discipline

This paper considers a batch-arrival single-server queueing system with multiple vacations and exhaustive service discipline. Customers arrive to the system in accordance with a batch switched Poisson process (batchSPP). Using the supplementary variable technique, we analyze the stationary queue length distribution and derive various formulas for queue lengths and waiting times. In particular, we analytically show the decomposition property for the waiting time distributions. Therefore, the waiting time formulas developed in this paper can also be applied to a batchSPP/G/1 queue without vacations.     

Steady-state analysis of the MMPP/G/1/K queue

An exact analysis of the MMPP/G/1/K queuing model is carried out, yielding the whole buffer occupancy probability distribution and in particular the loss probability. The solution is obtained by an algorithmic procedure and requires only algebraic manipulations. An expression for the Laplace-Stieltjes transform of the virtual waiting time distribution is derived     

Calculating time-dependent performance measures for the M/M/1 queue

Methods are discussed for computing transient performance measures for the M/M/1 queue. These performance measures are often expressed in terms of modified Bessel functions without any discussion about computation. In fact, a common expression for the probability transition function of the M/M/1 queue length process has an infinite sum of modified Bessel functions. For actually generating numbers, however, it is convenient to use numerical integration with associated integral representations, as was first pointed out by P.M. Morse (Oper. Res., vol.3, p.255-61, 1955)     

Analysis of an M/G/1/N queue with vacations and its iterativeapplication to FDDI timed-token rings

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     

Delay analysis of a packet voice multiplexer by the ΣDi/D/1 queue

The performance of a statistical multiplexer whose inputs consist of a superposition of voice packet streams is studied. The delay for such a system is analyzed by solving the ΣD_i/ D/1 queue. The analytic method can be used to find the approximate mean delay for an arbitrarily large number of trunks and the approximate delay distribution when the number of trunks is less than 100. An efficient hybrid simulation of the packet voice multiplexer which can be used to find the delay distribution for a large number of trunks is presented. In addition, easily computable error bounds for the present approximation are provided, and the accuracy of the M/ D/1 approximation is investigated     

Perturbation analysis: the state of the art and research issuesexplained via the GI/G/1 queue

Perturbation analysis (PA) of discrete event dynamic systems (DEDS) enables parameter sensitivities of DEDS to be obtained by observing a single sample path of the system. A simple GI/G/1 system is used to give an introduction to PA and illustrate the basic theoretical issues involved in this technique. The application of PA to networks of queues is covered briefly, and then some of the recent extensions to PA are discussed. It is shown that many interesting open questions remain for PA, and areas for research are indicated     

Modeling the influence of arsenic autodoping on the sheet resistance of epitaxial silicon films and its application to statistical process control (SPC)

An epitaxial layer sheet resistance monitoring procedure has been developed to overcome the convolution between intentional epilayer doping and arsenic autodoping for multiwafer reactors. The procedure models the epilayer as an intentionally phosphorous-doped region plus an arsenic autodoped region by approximating the epilayer as two resistors in parallel. The resulting sheet resistance SPC monitoring procedure is sensitive to shifts in epilayer carrier concentration as well as arsenic autodoping induced by product lots.     

Monolithic integrated 4:1 multiplexer and demultiplexer operating up to 4.8 Gbit/s

The letter describes the high-speed performance of a 4:1 time-division MSI multiplexer and demultiplexer, which are fabricated using advanced super self-aligned process technology (SST). The maximum operation speed of the multiplexer is 5.02 GHz under 576 mW power dissipation. The system, which is composed of a multiplexer and a demultiplexer, operates at up to 4.80 GHz. The demultiplexer has a power dissipation of 1148 mW. Interchannel interference is also examined.     

The state-dependent queue: M/M/1/N with reneging and general balk functions

The truncated single - channel queue: M/M/1/N with state-dependent, reneging and general balk functions is treated. Also different state-dependent are considered. The discipline is the classical one FIFO. The probability there are n units in the system, and also some measures of effectiveness are deduced in the steady-state case.     

锂离子电池正极材料LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2的合成及性能研究

采用辐照凝胶法制备了锂离子电池正极用LiNi1/3Co1/3Mn1/3O2粉体材料。采用XRD、SEM和电化学充放电测试对制备材料的结构和性能进行了表征。结果表明:900℃制得的样品具有较好的层状结构,结晶性适中,电化学性能优异:其首次放电容量高达184mA·h/g(2.80～4.50V,C/10),30次循环后的容量保持率为87.4%,表现出较好的充放电容量和循环性能,较之850,950℃煅烧样品具有最小的交流阻抗和直流阻抗。     

Testing process performance based on the yield: an application to the liquid-crystal display module

Process capability indices have been introduced to provide numerical measures on whether a manufacturing process is capable of reproducing items meeting the specifications predetermined by the product designers or the consumers. Process yield is one of the most common criteria used in the manufacturing industry for measuring process performance. The formula S_pk has been proposed to calculate the process yield for normal processes. The formula S_pk provides an exact measure on the process yield. Unfortunately, the statistical properties of the estimated are mathematically intractable. In this paper, we apply the bootstrap simulation method to construct the lower confidence bound of S_pk. We then present a real-world application to the liquid-crystal display module process, to illustrate how we may apply the formula S_pk to actual data collected from the factories.     

掺镱PCF的端面处理工艺及激光性能研究（特邀）

基于自制的掺镱大模场光子晶体光纤,探索出一种高效快速的光子晶体光纤端面处理工艺。使用二氧化碳激光熔接机对光子晶体光纤进行旋转加热处理,并配合大口径光纤切割刀对塌缩区域进行切割。通过对比光纤在不同激光加热功率和加热时间下的塌缩效果,确定了最佳的加热功率和时间。对端面处理后的光纤进行激光震荡实验,测试光纤的激光性能,与未进行端面处理时的激光实验结果相比较,端面塌缩处理没有对光纤的激光性能产生较大的影响。通过所述的实验方法,成功得到高质量光子晶体光纤塌缩端面,空气孔塌缩界面齐整,且没有对光纤本身的激光性能产生较大的影响。实验工艺周期短、成功率高,证明利用激光加热塌缩来处理光子晶体光纤端面是一种非常有效的方法,极大地拓展了光子晶体光纤的使用范围,具有很强的实用价值。