具有等待者的Kornai—Weibull排队模型的修正与分析

这篇文章首先明确地指出，具有等待的买者的Ｋｏｒｎａｉ－Ｗｅｉｂｕｌｌ排队模型与没有等待者的Ｋｏｒｎａｉ－Ｗｅｉｂｕｌｌ排队模型具有要同的纰漏，其次，本文在较自然条件下严格证明了修正后模型存在的“正常状态”研究Ｋｏｒｎａｉ－Ｗｅｉｂｕｌｌ排队模型理论能够深刻地揭示了计划经济的弊端。     

Kornai－Weibull排队模型的纰漏，修正与分析

本文首先指出Ｋｏｒｎａｉ－Ｗｅｉｂｕｌｌ排队模型（Ａ）中之接待率ｒ（ｙ_１）的定义是不正确的，并给出接待率ｒ（ｙ_１，ｙ₂）的正确定义．其次，证明了修正模型（１）有“正常状态”的充要条件是接待能力(?)于是，本文发现接待能力Ｓ的分歧值是Ｓ^＊；当Ｓ＜Ｓ^＊时，市场是短缺的；当Ｓ≥Ｓ^＊时，市场是不短缺的．     

两参数Weibull分布平均寿命的置信下限

王蓉华，徐晓岭．两参数Ｗｅｉｂｕｌ分布平均寿命的置信下限．数理统计与管理，１９９８，１７（２），４３～４５．本文给出了求两参数Ｗｅｉｂｕｌ分布定数截尾下平均寿命置信下限的一种方法     

K-强凸性与K-强光滑性

本文引进了Ｋ－强凸性的概念，它是强凸性概念的推广．然后证明了Ｋ－强凸性与Ｋ－强光滑具有对偶性质；Ｘ为Ｋ－强光滑当且仅当Ｘ是自反且Ｋ－强凸；自反的Ｂａｎａｃｈ空间Ｘ是Ｋ－强凸当且仅当Ｘ是Ｋ－严格凸且具有（Ｈ）性质；局部Ｋ－一致凸空间是Ｋ－强凸的，从而推广了文［２－４］的结果．最后利用Ｋ－强暴露点的概念刻划了Ｋ－强光滑空间的特征，从而推广了［７］的结果．     

■－方程的积分解算子的局部C~k－边界正则性

作为ＣｈｅｎＺ．［１］的推广，文中证明了（ｐ，ｑ）－形式的三方程的Ｋｏｐｐｅｌｍａｎ－Ｌｅｒａｙ算子Ｔｐ，ｑ和Ｋｏｐｐｅｌｍａｎ算子Ｈｐ，ｑ解在具片段Ｃ１－边界的开集Ｄ上局部地保持边界点的实解析性．     

δ^—方程的积分解算子的局部C^k一边界正则性

作为ＣｈｅｎＺ．「１」的推广，文中证明了（ｐ，ｑ）－形式的δ＾－方程的Ｋｏｐｐｅｌｍａｎ－Ｌｅｒａｙ算子Ｔｐ，ｑ和Ｋｏｐｐｅｌｍａｎ算子Ｈｐ，ｑ解在具片段Ｃ＾１－边界的开集Ｄ上局部地保持边界点的实解析性。     

关于低阶K群的若干问题

本文主要介绍了低阶Ｋ群Ｋ＿０，Ｋ＿１，Ｋ＿２及与它们相关的Ｂａｓｓ－Ｑｕｉｌｌｅｎ猜测、Ｂｉｒｃｈ－Ｔａｔｅ猜测研究的最新进展．Ｋ＿０与Ｋ＿１方面主要通过对Ｂａｓｓ～Ｑｕｉｌｌｅｎ猜测研究说明Ｋ＿０，Ｋ＿１的作用，同时也给出了一些多项式环上投射模自同构群的计算公式．在Ｋ＿２群方面，我们主要介绍了域上Ｋ＿２群，代数整数环上Ｋ＿２群以及著名的Ｂｉｒｃｈ－Ｔａｔｅ猜想．并且也给出了Ｋ＿２群一些计算方面的结果．     

H—空间的覆盖性质及其应用

我们得到了Ｈ－空间闭（开）覆盖性质的几个定理，改进和推广了Ｓｐｅｒｎｅｒ，Ｋｌｅｅ，Ａｌｅｘａｎｄｒｏｆｆ－Ｐａｓｙｎｋｏｆｆ，Ｂｅｒｇｅ，Ｇｈｏｕｉｌａ－Ｈｏｕｒｉ，Ｄａｎｚｅｒ－Ｇｒｕｎｂａｕｍ－Ｋｌｅｅ，Ｋｙ Ｆａｎ，ｓｈｉｈ－Ｔａｎ，Ｈｏｒｖａｔｈ和Ｌａｓｓｏｎｄｅ等人的相应结果。作为应用，我们对ｌ．ｃ．－空间内的下半连续集值映象证明了一个几站不动点定理并且推广吉洪诺夫不动点定理到ｌ．ｃ．     

关于二部图K(m,n)-2的色唯一性

设Ｋ（ｍ，ｎ）－２表示从完全二部图Ｋ（ｍ，ｎ）中删去任意２条边所得之图．本文证明了：１．若ｎ≥ｍ≥３，且ｎ＋ｍ＞(（ｎ－ｍ）^２＋８)^1/2＋１/２（ｎ－ｍ）^２＋４，则Ｋ（ｍ，ｎ）－２是色唯一图；２．当ｍ≥３时，Ｋ（ｍ，ｍ）－２，Ｋ（ｍ，ｍ＋１）－２和Ｋ（ｍ，ｍ＋２）－２均是色唯一图．     

几类不具有捏制轨道系列完整性的单峰函数族

本文证明，存在着由单峰函数构成的Ｃｏ－函数族｛ｆλ），｛ｇλ｝及具有下列性质：（ｉ）各ｆλ均是分段线性的单峰平顶函数，各ｇλ及均是Ｃ∞－单峰平顶函数．但族｛ｆλ｝，｛ｇλ｝及均非一致平顶；（ｉｉ）族｛ｆλ｝及｛ｇλ｝均满足一致的Ｌｉｐｓｃｈｉｔｚ条件，但在峰顶处均非一致地可微；（ｉｉｉ）族在峰顶处一致地可微，但不满足一致的Ｌｉｐｓｃｈｉｔｚ条件；（ｉｖ）当０≤λ≤７／８时捏制序列Ｋ（ｆλ），Ｋ（ｇλ）及以均不大于ＲＬＣ，当７／８＜λ－≤１时Ｋ（ｆλ），Ｋ（ｇλ）及Ｋ均不小于ＲＬＬ（ＲＬＲ）∞，因而族｛ｆλ｝，｛ｇλ｝及均不具有捏制轨道系列的完整性．本文的结果解答了文［５］中提出的两个猜测．     

Marginal queue length approximations for a two-layered network with correlated queues

We consider an extension of the classical machine-repair model, where we assume that the machines, apart from receiving service from the repairman, also serve queues of products. The extended model can be viewed as a layered queueing network, where the first layer consists of the queues of products and the second layer is the ordinary machine-repair model. As the repair time of one machine may affect the time the other machine is not able to process products, the downtimes of the machines are correlated. This correlation leads to dependence between the queues of products in the first layer. Analysis of these queue length distributions is hard, as the exact dependence structure for the downtimes, or the queue lengths, is not known. Therefore, we obtain an approximation for the complete marginal queue length distribution of any queue in the first layer, by viewing such a queue as a single server queue with correlated server downtimes. Under an explicit assumption on the form of the downtime dependence, we obtain exact results for the queue length distribution for that single server queue. We use these exact results to approximate the machine-repair model. We do so by computing the downtime correlation for the latter model and by subsequently using this information to fine-tune the parameters we introduced to the single server queue. As a result, we immediately obtain an approximation for the queue length distributions of products in the machine-repair model, which we show to be highly accurate by extensive numerical experiments.     

带有Bernoulli控制策略的M/M/1多重休假排队模型

研究具有Bernoulli控制策略的M/M/1多重休假排队模型: 当系统为空时, 服务台依一定的概率或进入闲期, 或进入普通休假状态, 或进入工作休假状态. 对该模型, 应用拟生灭(QBD)过程和矩阵几何解的方法, 得到了过程平稳队长的具体形式, 在此基础上, 还得到了平稳队长和平稳逗留时间的随机分解结果以及附加队长分布和附加延迟的LST的具体形式. 结果表明, 经典的M/M/1排队, M/M/1多重休假排队, M/M/1多重工作休假排队都是该模型的特殊情形.     

Optimizing buffer size for the retrial queue: two state space collapse results in heavy traffic

We study a single server queueing model with admission control and retrials. In the heavy traffic limit, the main queue and retrial queue lengths jointly converge to a degenerate two-dimensional diffusion process. When this model is considered with holding and rejection costs, formal limits lead to a free boundary curve that determines a threshold on the main queue length as a function of the retrial queue length, above which arrivals must be rejected. However, it is known to be a notoriously difficult problem to characterize this curve. We aim instead at optimizing the threshold on the main queue length independently of the retrial queue length. Our main result shows that in the small and large retrial rate limits, this problem is governed by the Harrison–Taksar free boundary problem, which is a Bellman equation in which the free boundary consists of a single point. We derive the asymptotically optimal buffer size in these two extreme cases, as the scaling parameter and the retrial rate approach their limits.     

On a generic class of two-node queueing systems

This paper analyzes a generic class of two-node queueing systems. A first queue is fed by an on–off Markov fluid source; the input of a second queue is a function of the state of the Markov fluid source as well, but now also of the first queue being empty or not. This model covers the classical two-node tandem queue and the two-class priority queue as special cases. Relying predominantly on probabilistic argumentation, the steady-state buffer content of both queues is determined (in terms of its Laplace transform). Interpreting the buffer content of the second queue in terms of busy periods of the first queue, the (exact) tail asymptotics of the distribution of the second queue are found. Two regimes can be distinguished: a first in which the state of the first queue (that is, being empty or not) hardly plays a role, and a second in which it explicitly does. This dichotomy can be understood by using large-deviations heuristics. This work has been carried out partly in the Dutch BSIK/BRICKS project.     

The infinite-buffer single server queue with a variant of multiple vacation policy and batch Markovian arrival process

We consider an infinite-buffer single server queue where arrivals occur according to a batch Markovian arrival process (BMAP). The server serves until system emptied and after that server takes a vacation. The server will take a maximum number H of vacations until either he finds at least one customer in the queue or the server has exhaustively taken all the vacations. We obtain queue length distributions at various epochs such as, service completion/vacation termination, pre-arrival, arbitrary, departure, etc. Some important performance measures, like mean queue lengths and mean waiting times, etc. have been obtained. Several other vacation queueing models like, single and multiple vacation model, queues with exceptional first vacation time, etc. can be considered as special cases of our model.     

Decay rate for a PH/M/2 queue with shortest queue discipline

In this paper, we consider a PH/M/2 queue in which each server has its own queue and arriving customers join the shortest queue. For this model, it has been conjectured that the decay rate of the tail probabilities for the shortest queue length in the steady state is equal to the square of the decay rate for the queue length in the corresponding PH/M/2 model with a single queue. We prove this fact in the sense that the tail probabilities are asymptotically geometric when the difference of the queue sizes and the arrival phase are fixed. Our proof is based on the matrix analytic approach pioneered by Neuts and recent results on the decay rates. AMS subject classifications: 60K25 · 60K20 · 60F10 · 90B22     

Stationary tail asymptotics of a tandem queue with feedback

Motivated by applications in manufacturing systems and computer networks, in this paper, we consider a tandem queue with feedback. In this model, the i.i.d. interarrival times and the i.i.d. service times are both exponential and independent. Upon completion of a service at the second station, the customer either leaves the system with probability p or goes back, together with all customers currently waiting in the second queue, to the first queue with probability 1−p. For any fixed number of customers in one queue (either queue 1 or queue 2), using newly developed methods we study properties of the exactly geometric tail asymptotics as the number of customers in the other queue increases to infinity. We hope that this work can serve as a demonstration of how to deal with a block generating function of GI/M/1 type, and an illustration of how the boundary behaviour can affect the tail decay rate.     

Tail asymptotics for service systems with transfers of customers in an alternating environment

This study examines service systems with transfers of customers in an alternating environment. We model the service system as a two-server two-parallel queue (primary and auxiliary queues), that has various applications especially in manufacturing and healthcare systems. We establish a sufficient stability condition, and based on the censoring technique, we provide sufficient conditions under which the stationary distribution possesses an exactly geometric tail along the direction of the queue length in the primary queue.     

Economies of scale,competitiveness, and trade patterns within the European community: Clarendon Press,Oxford, 1983, 193 pages, £20.00

We consider two queues in series with input to each queue, which can be controlled by accepting or rejecting arriving customers. The objective is to maximize the discounted or average expected net benefit over a finite or infinite horizon, where net benefit is composed of (random) rewards for entering customers minus holding costs assessed against the customers at each queue. Provided that it costs more to hold a customer at the first queue than at the second, we show that an optimal policy is monotonic in the following senses: Adding a customer to either queue makes it less likely that we will accept a new customer into either queue; moreover moving a customer from the first queue to the second makes it more (less) likely that we will accept a new customer into the first (second) queue. Our model has policy implications for flow control in communication systems, industrial job shops, and traffic-flow systems. We comment on the relation between the control policies implied by our model and those proposed in the communicationa literature.