M/M/l/k后馈系统中的随机过程

本文对M/M/1/k后馈排队系统中各随机过程的Poisson性进行了讨论,推广了Br(?)ma(?)d([2],[3])的相应结果.所得结论表明M/M/1/k后馈系统与M/M/1后馈系统情况有所不同,即在某些情况下,除了总输出过程外,还有其它的过程也可能是Poisson过程.顺便又对M/M/C/k前馈后馈排队系统的动态数学模型进行了严格的讨论.     

多重休假M^x/G/l排队系统的输出过程

本文首次研究服务员具有多重休假规则的成批到达M^x/G/l排队系统的输出过程．应用更新过程理论、拉普拉斯-司梯阶变换和本文提出的直接概率分解分析法，讨论了从任意初始状态出发，系统在（O，t）时间内输出顾客的平均数，以及其渐近展开，得到一些重要结果．     

延迟Min(N,D)-策略下M/G/1排队系统的离去过程

考虑延迟Min(N, D)-策略下M/G/1排队系统的离去过程.运用全概率分解技术、更新过程理论和Laplace-Stieltjes变换,从任意初始状态出发,讨论在有限区间(0, t]内离去顾客的平均数,给出了离去过程、服务员状态过程和服务员忙期中的服务更新过程之间的关系,该关系揭示了离去过程的随机分解特性,并得到了离去顾客平均数的渐近展开式.在排队网络中,由于一个排队系统的输出即为下游排队系统的输入,希望本文所得结果为排队网络的研究提供有用的信息.     

M/M/∞随机服务系统的一个递推方法

本文提出一个处理 M/M/∞随机服务系统瞬时行为的交错递推方法.由此不仅可得瞬时状态分布,还给出各种二维随机过程及输出过程的分布、一系列瞬时条件分布、诸过程的瞬时相关系数.最后,当 t 充分大时,对各种瞬时概率给出方便的渐近公式.     

M／M^r／1／N排队系统

本文讨论了等待空间有限的成批服务排队系统M/M~r/1/N,给出队长平稳分布的精确解.还得到了系统损失概率和平均输出间隔的精确值.     

一类非线性微分-代数系统的状态/输出反馈镇定

针对一类可能含有非Lipschitz连续性非线性项的非线性微分-代数系统的状态/输出反馈镇定问题进行研究.首先,利用反步法给出了一种状态反馈控制器的递归设计方法.其次,在非线性项和代数约束满足适当的假设条件下,基于输出反馈占优技术得到了一种输出反馈控制器的设计方法.虽然所给出的两种控制器仅依赖于微分系统的状态,但均能够保证闭环系统的状态是渐近稳定的.仿真结果验证了所提出的两种控制方法的有效性.     

离散时间Geo~(λ_1,λ_2)/G/1(ES,MV)排队系统离去过程的分解

考虑顾客到达率可变的多重休假Geo/G/1排队系统的离去过程.运用全概率分解,更新过程理论和u-变换,讨论了从任意初始状态出发,在(0⁺,n+,n⁺]中离去顾客的平均数,得到系统在(0+]中离去顾客的平均数,得到系统在(0⁺,n+,n⁺]中离去顾客平均数的瞬态分解表达式,以及其稳态分解结果.揭示了系统离去更新过程的特殊结构:离去更新过程被分解为两部分,一部分是系统服务状态(忙,闲)过程,另一部分是忙期中的服务更新过程,从而简化了对离去过程的研究.在排队网络中,由于一个排队系统的输出即为下游排队系统的输入,因此,本文所得结果对研究排队网络有重要意义.     

具有Bernoulli休假的M/G/1重试可修的排队系统

本文研究了具有Bernoulli休假、一般重试的服务台可修的M/G/1排队系统,求得系统稳态解存在的充分必要条件.利用补充变量法求得系统的排队指标和可靠性指标.     

N-策略 CI/M/1 随机服务系统

本文讨论 N-策略 GI/M/1 随机服务系统.使用嵌入 Markov 链方法,给出稳态到达时刻队长和等待时间的分布和随机分解,把系统的忙期归结为经典排队中 k 阶忙期的已知结果.     

带有破坏性负顾客的Geo/Geo/1/MWV可修排队系统均衡策略研究

本文研究带有破坏性负顾客的离散时间Geo/Geo/1/MWV可修排队系统的顾客策略行为.当破坏性负顾客到达系统时,会移除正在接受服务的正顾客,同时造成服务台故障.服务台一旦发生损坏,会立刻接受维修,修理时间服从几何分布.服务台在工作休假期间会以较低的服务速率对顾客进行服务.我们求得系统的稳态分布,进一步给出服务台不同状态下的均衡进入率以及系统单位时间的社会收益表达式.最后对均衡进入率和均衡社会收益进行了数值分析.     

On stationary queue length distributions for G/M/s/r queues

Consider aG/M/s/r queue, where the sequence{A _n } _n=– of nonnegative interarrival times is stationary and ergodic, and the service timesS _n are i.i.d. exponentially distributed. (SinceA _n =0 is possible for somen, batch arrivals are included.) In caser < , a uniquely determined stationary process of the number of customers in the system is constructed. This extends corresponding results by Loynes [12] and Brandt [4] forr= (with=ES₀/EA₀<s) and Franken et al. [9], Borovkov [2] forr=0 ors=. Furthermore, we give a proof of the relation min(i, s)¯p(i)=p(i–1), 1ir + s, between the time- and arrival-stationary probabilities¯p(i) andp(i), respectively. This extends earlier results of Franken [7], Franken et al. [9].     

Scientific heritage of Boris Lukich Laptev (4/23/05–1/15/89)

Biographical information on the eminent Soviet geometer Boris Lukich Laptev (4/23/05–1/15-89) is given as well as a survey of his research in the areas of differential geometry and history of mathematics.Translated from Itogi Nauki i Tekhniki, Seriya Problemy Geometrii, Vol. 21, pp.27–42, 1989.     

A G/M/1-queue with exponential retrial

Summary We consider a G/M/1 retrial model in which the delays between retrials are i.i.d. exponentially distributed random variables. We investigate the steady-state distribution of the embedded Markov chain at completion service epochs, the stationary distribution at anytime and the virtual waiting time.     

On the M/G/1 queue with D-policy

This paper deals with the M/G/1 queue with D-policy, i.e., the server is turned off at the end of a busy period and turned on when the cumulative amount of work firstly exceeds some fixed value D. We first concentrate on the computation of the steady-state probabilities. The first moments and relationships among the busy period, the number of customers served and other performance measures are investigated. Some variants of the main model and the special case of the M/M/1 are also studied.     

An M/M/1 retrial queue with unreliable server

We analyze an unreliable M/M/1 retrial queue with infinite-capacity orbit and normal queue. Retrial customers do not rejoin the normal queue but repeatedly attempt to access the server at i.i.d. intervals until it is found functioning and idle. We provide stability conditions as well as several stochastic decomposability results.     

Modified Taylor reproducing formulas and h-p clouds

We study two different approximations of a multivariate function by operators of the form , where is an -reproducing partition of unity and are modified Taylor polynomials of degree expanded at . The first approximation was introduced by Xuli (2003) in the univariate case and generalized for convex domains by Guessab et al. (2005). The second one was introduced by Duarte (1995) and proved in the univariate case. In this paper, we first relax the Guessab's convexity assumption and we prove Duarte's reproduction formula in the multivariate case. Then, we introduce two related reproducing quasi-interpolation operators in Sobolev spaces. A weighted error estimate and Jackson's type inequalities for h-p cloud function spaces are obtained. Last, numerical examples are analyzed to show the approximative power of the method.

     

Matched queueing system MoPH/G/1

In this paper, we study the matched queueing system, MoPH/G/1, where the type-I input is a Poisson process, the type-II input is a PH renewal process, and the service times are i.i.d. random variables. A necessary and sufficient condition for the stationariness of the system is given. The expectations of the length of the non-idle period and the number of customers served in a non-idle period are obtained.This project is supported by the National Natural Science Foundation of China and partially by the Institute of Mathematics, Academia Sinica.     

On the Moments of Overflow and Freed Carried Traffic for the GI/M/C/0 System

In circuit-switched networks call streams are characterized by their mean and peakedness (two-moment method). The GI/M/C/0 system is used to model a single link, where the GI-stream is determined by fitting moments appropriately. For the moments of the overflow traffic of a GI/M/C/0 system there are efficient numerical algorithms available. However, for the moments of the freed carried traffic, defined as the moments of a virtual link of infinite capacity to which the process of calls accepted by the link (carried arrival process) is virtually directed and where the virtual calls get fresh exponential i.i.d. holding times, only complex numerical algorithms are available. This is the reason why the concept of the freed carried traffic is not used. The main result of this paper is a numerically stable and efficient algorithm for computing the moments of freed carried traffic, in particular an explicit formula for its peakedness. This result offers a unified handling of both overflow and carried traffics in networks. Furthermore, some refined characteristics for the overflow and freed carried streams are derived.     

Involutions fixing , II

This paper studies the equivariant cobordism classification of all involutions fixing a disjoint union of an odd-dimensional real projective space with its normal bundle nonbounding and a Dold manifold with a positive even and 0$">. The complete analysis of the equivariant cobordism classes of such involutions is given except that the upper and lower bounds on the codimension of may not be best possible. In particular, we find that there exist such involutions with nonstandard normal bundle to . Together with the results of part I of this title (Trans. Amer. Math. Soc. 354 (2002), 4539-4570), the argument for involutions fixing is finished.

     

On the boundaries of self-similar tiles in

The aim of this note is to study the construction of the boundary of a self-similar tile, which is generated by an iterated function system . We will show that the boundary has complicated structure (no simple points) in general; however, it is a regular fractal set.