The Performance Analysis Of A M/M/2/2＋ 1 Retrial Queue With Unreliable Server

The M/M/r/r＋d retrial queuing system with unreliable server is considered. The customers arrive according to a Poisson process and the service time distribution is negative exponential. The life time of the server and repair times are also negative exponential. If the system is full at the time of arrival of a customer, the customer enters into an orbit. From the orbit the customer tries his luck. The time between two successive retrial follows negative exponential distribution. The model is analyzed using Matrix Geometric Method. The joint distribution of system size and orbit size in steady state is studied. Some system performance measures are obtained. We also provide numerical examples by taking particular values to the parameters.

AN M/G/1 RETRIAL QUEUE WITH SECOND MULTI-OPTIONAL SERVICE,FEEDBACK AND UNRELIABLE SERVER

An M/G/1 retrial queue with two-phase service and feedback is studied in this paper, where the server is subject to starting failures and breakdowns during service. Primary customers get in the system according to a Poisson process, and they will receive service immediately if the server is available upon arrival. Otherwise, they will enter a retrial orbit and are queued in the orbit in accordance with a first-come-first-served （FCFS） discipline. Customers are allowed to balk and renege at particular times. All customers demand the first “essential” service, whereas only some of them demand the second “multi-optional” service. It is assumed that the retrial time, service time and repair time of the server are all arbitrarily distributed. The necessary and sufficient condition for the system stability is derived. Using a supplementary variable method, the steady-state solutions for some queueing and reliability measures of the system are obtained.

Availability and cost-benefit evaluation for a repairable retrial system with warm standbys and priority

This paper investigates a warm standby repairable retrial system with two types of components and a single reparman,where type 1 components have priority over type 2 in use.Failure and repair times for each type of component are assumed to be exponential distributions.The retrial feature is considered and the retrial time of each failed component is exponentially distributed.By using Markov process theory and matrix analytic method,the system steady-state probabil-ities are derived,and the system steady-state availability and some steady-state performance indices are obtained.Using the Bayesian approach,the system parameters can be estimated.The cost-benefit ratio function of the system is constructed based on the failed components and repairman's states.Numerical experiments are given to evaluate the effect of each parameter on the system steady-state availability and optimize the system cost-benefit ratio with repair rate as a decision variable.

AN M/M/C RETRIAL QUEUEING SYSTEM WITH BERNOULLI VACATIONS

In this paper, a steady-state Markovian multi-server retrial queueing system with Bernoulli vacation scheduling service is studied. Using matrix-geometric approach, various interesting and important system performance measures are obtained. Further, the probability descriptors like ideal retrial and vain retrial are provided. Finally, extensive numerical illustrations are presented to indicate the quantifying nature of the approach to obtain solutions to this queueing system.

DISCRETE-TIME Geo/G/1 RETRIAL QUEUES WITH GENERAL RETRIAL TIME AND BERNOULLI VACATION

This paper considers a discrete-time Geo/G/1 retrial queue where the retrial time has a general distribution and the server is subject to Bernoulli vacation policy. It is assumed that the server, after each service completion, begins a process of search in order to find the following customer to be served with a certain probability, or begins a single vacation process with complementary probability. This paper analyzes the Markov chain underlying the queueing system and obtain its ergodicity condition. The generating functions of the number of customers in the orbit and in the system are also obtained along with the marginal distributions of the orbit size when the server is idle, busy or on vacation. Finally, the author gives two stochastic decomposition laws, and as an application the author gives bounds for the proximity between the system size distributions of the model and the corresponding model without retrials.

我国民事再审审查程序的反思和优化

民事再审审查程序是民事再审审理程序的前置环节,对于保障当事人、案外人申请再审权,过滤不符合再审条件的申请再审案件具有重要价值。当前,虽然我国立法已从管辖法院、审查方式、申请再审事由等方面对该程序作了较为全面的规定,但仔细审视,民事再审审查程序仍存在再审申请的管辖法院不利于发挥各级法院应有职能、申请再审原则上免交案件受理费不利于控制再审审查案件数量、以书面审查为主的审查方式不利于保障申请人程序参与权以及“新证据”的认定标准不利于统一再审审查的结果等问题。为进一步优化民事再审审查程序,正确定位四级法院的审级职能,应将再审申请的管辖法院统一规定为原审法院,完善申请再审案件的受理费交纳规则,提升询问、听证等审查方式的适用频率,并正确把握再审审查阶段“新证据”的认定标准。

再审新证据的类型化及运用路径研究

相较于原审,再审新证据皆为逾期举证,但《民事诉讼法》对逾期举证主观方面未差异对待,而是进行训诫或罚款后均可采纳,造成举证责任原审和再审冲突,原审还会被误定为错案,亦有放纵不诚信诉讼之嫌。为充分维护法律秩序的稳定性,原审结束后因新发生事实形成的证据,不宜通过启动再审使用。对新证据主观认知和形成时间两个角度进行差异化分类,即对涉及国家利益、公共利益和他人合法利益的逾期举证均给予机会且不处罚,对影响自身重大利益的处罚后采纳,其余故意逾期者均不采纳。对原审结束后新形成的证据宜采用变更判决方式拓展运用路径,以维护原判权威,同时保护当事人权益,提升司法效率,节约审判资源。

我国刑事再审“不利于被告人利益启动规则”研究

我国刑事再审程序一直对已经发生法律效力的裁判“有错必纠”,并不区分启动事由上是否“有利于被告人利益”或“不利于被告人利益”,刑事再审的启动主体、启动事由、运行规范等都为实现纠错功能而运转。为维护法的安定性、法的权威性,应回归刑事诉讼客体理论,确立案件事实及其法律评价在刑事司法程序运行中的价值,夯实刑事再审的客体内容,厘定生效裁判效力的涵摄范围;为禁止法院、检察院为“不利于被告人利益”而启动再审程序。实质上,在《刑事诉讼法》总则中应确立不告不理原则、控审同一原则、一事不再理原则,形式上,明确“不利于被告人利益”的启动事由。

刑事再审抗诉实证研究——以360份裁判文书为样本

刑事抗诉是检察机关法律监督工作的重要组成部分,逐渐成为刑事审判监督格局的中心。司法实践中,适用法律错误与量刑错误是检察机关提起再审抗诉的主要理由。从再审抗诉结果上看,绝大多数抗诉意见都得到法院支持;从再审抗诉质量上看,检察机关对实体性问题提出再审抗诉的质量高于对程序性问题的抗诉质量;从再审抗诉功能的实践样态上看,再审抗诉的追诉色彩浓厚,纠错功能突出,检察机关的中立地位偏移,监督属性不足。检察机关应回归客观中立立场,严格控制不利于被告人再审抗诉的提起,实现再审抗诉“实体+程序”双轮驱动,提升再审抗诉工作质效。

论破产债权审查中第三人撤销之诉的适用

面对破产债权审查中以虚假生效法律文书申报债权的频发现象,具有打击虚假诉讼功能的第三人撤销之诉为破产债权人提供了审判监督程序以外的又一救济路径。基于破产程序参与主体多元、利益纷争复杂的特殊性,应当对第三人撤销之诉的适用做出特殊安排与协调。破产程序中提起第三人撤销之诉的适格原告范围既涵盖全体破产债权人,也包括管理人,但原则上应由管理人提起,仅在管理人怠于行使其职权时,单个破产债权人方能提起。第三人撤销之诉仅依照我国民事诉讼法由作出原判决、裁定、调解书的法院审理,而不适用破产法集中管辖之规定。在既可以通过第三人撤销之诉又可以通过审判监督程序救济时,管理人可任意选择适用,但选择其一便视为对另一救济程序的放弃。

刑事二审发回重审制度实证研究——以河南省为例

刑事二审发回重审制度融合了保障人权和司法监督之双重功能,但在制度运行中异化为发回重审不开庭、发回标准不清晰、司法说理不明确和发回重审适用率大于改判的乱象,制度预设的保障与监督功能无法实现。在刑事诉讼法再修改的背景下,应当坚持无罪推定的精神,对刑事二审发回重审制度进行完善。首先,在发回标准上,完善实体性和程序性发回重审的规定;其次,在审判方式上,应当开庭审理;再次,在重审法院选择上,将范围扩大到原审法院之外的其他同级法院;最后,限制程序性发回的次数。

行政诉讼的二审裁判及其具体适用——《行政诉讼法》第八十九条评注

现行《行政诉讼法》第八十九条是有关二审裁判的规定,其相较1989年《行政诉讼法》第六十一条做了较大修改与完善。二审裁判根据其针对的是一审判决还是裁定区分为两类,前者的裁判类型包括驳回上诉维持原判、撤销原判依法改判、发回重审以及作为例外的裁定驳回起诉;而后者的裁判类型则包括维持和撤销变更原裁定两类。二审裁判的适用标准关联二审的审查方式和审查范围,同样参考了提高二审监督能力的现实考虑。禁止不利变更原则虽未明确写入《行政诉讼法》中,但其不仅适用于变更判决,同样适用于二审裁判。二审裁判具有终局效果,但其既判力的拘束程度又取决于再审事由的判断,取决于实质正义与法安定性的价值权衡。

A Batch Arrival Retrial Queue with Two Phases of Service and Bernoulli Vacation Schedule

We consider an MX/G/1 queueing system with two phases of heterogeneous service and Bernoulli vacation schedule which operate under a linear retrial policy. In addition, each individual customer is subject to a control admission policy upon the arrival. This model generalizes both the classical M/G/1 retrial queue with arrivals in batches and a two phase batch arrival queue with a single vacation under Bernoulli vacation schedule. We will carry out an extensive stationary analysis of the system, including existence of the stationary regime, embedded Markov chain, steady state distribution of the server state and number of customer in the retrial group, stochastic decomposition and cMculation of the first moment.

A DISCRETE-TIME Geo/G/1 RETRIAL QUEUE WITH J-VACATION POLICY AND GENERAL RETRIAL TIMES

The authors discuss a discrete-time Geo/G/1 retrial queue with J-vacation policy and general retrial times.As soon as the orbit is empty,the server takes a vacation.However,the server is allowed to take a maximum number J of vacations,if the system remains empty after the end of a vacation.If there is at least one customer in the orbit at the end of a vacation,the server begins to serve the new arrivals or the arriving customers from the orbit.For this model,the authors focus on the steady-state analysis for the considered queueing system.Firstly,the authors obtain the generating functions of the number of customers in the orbit and in the system.Then,the authors obtain the closed-form expressions of some performance measures of the system and also give a stochastic decomposition result for the system size.Besides,the relationship between this discrete-time model and the corresponding continuous-time model is also investigated.Finally,some numerical results are provided.

A BATCH ARRIVAL RETRIAL QUEUE WITH STARTING FAILURES,FEEDBACK AND ADMISSION CONTROL

This paper is concerned with the analysis of a feedback M^[X]/G/1 retrial queue with starting failures and general retrial times. In a batch, each individual customer is subject to a control admission policy upon arrival. If the server is idle, one of the customers admitted to the system may start its service and the rest joins the retrial group, whereas all the admitted customers go to the retrial group when the server is unavailable upon arrival. An arriving customer （primary or retrial） must turn-on the server, which takes negligible time. If the server is started successfully （with a certain probability）, the customer gets service immediately. Otherwise, the repair for the server commences immediately and the customer must leave for the orbit and make a retrial at a later time. It is assumed that the customers who find the server unavailable are queued in the orbit in accordance with an FCFS discipline and only the customer at the head of the queue is allowed for access to the server. The Markov chain underlying the considered queueing system is studied and the necessary and sufficient condition for the system to be stable is presented. Explicit formulae for the stationary distribution and some performance measures of the system in steady-state are obtained. Finally, some numerical examples are presented to illustrate the influence of the parameters on several performance characteristics.

A RepairableGeoX/G/1 Retrial Queue with Bernoulli Feedback and Impatient Customers

Abstract This paper deals with a discrete-time batch arrival retrial queue with the server subject to starting failures.Diferent from standard batch arrival retrial queues with starting failures,we assume that each customer after service either immediately returns to the orbit for another service with probabilityθor leaves the system forever with probability 1θ（0≤θ〈1）.On the other hand,if the server is started unsuccessfully by a customer（external or repeated）,the server is sent to repair immediately and the customer either joins the orbit with probability q or leaves the system forever with probability 1 q（0≤q〈1）.Firstly,we introduce an embedded Markov chain and obtain the necessary and sufcient condition for ergodicity of this embedded Markov chain.Secondly,we derive the steady-state joint distribution of the server state and the number of customers in the system/orbit at arbitrary time.We also derive a stochastic decomposition law.In the special case of individual arrivals,we develop recursive formulae for calculating the steady-state distribution of the orbit size.Besides,we investigate the relation between our discrete-time system and its continuous counterpart.Finally,some numerical examples show the influence of the parameters on the mean orbit size.

A Single-server Discrete-time Retrial G-queue with Server Breakdowns and Repairs

This paper concerns a discrete-time Geo/Geo/1 retrial queue with both positive and negative customers where the server is subject to breakdowns and repairs due to negative arrivals. The arrival of a negative customer causes one positive customer to be killed if any is present, and simultaneously breaks the server down. The server is sent to repair immediately and after repair it is as good as new. The negative customer also causes the server breakdown if the server is found idle, but has no effect on the system if the server is under repair. We analyze the Markov chain underlying the queueing system and obtain its ergodicity condition. The generating function of the number of customers in the orbit and in the system are also obtained, along with the marginal distributions of the orbit size when the server is idle, busy or down. Finally, we present some numerical examples to illustrate the influence of the parameters on several performance characteristics of the system.

The MAP/PH/N Retrial Queue in a Random Environment

We consider the MAP/PH/N retrial queue with a finite number of sources operating in a finite state Markovian random environment. Two different types of multi-dimensional Markov chains are investigated describing the behavior of the system based on state space arrangements. The special features of the two formulations are discussed. The algorithms for calculating the stationary state probabilities are elaborated, based on which the main performance measures are obtained, and numerical examples are presented as well.

ON THE SINGLE SERVER RETRIAL QUEUE WITH PRIORITY SUBSCRIBERS AND SERVER BREAKDOWNS

The author concerned the reliability evaluation as well as queueing analysis of M1, M2/G1, G2/1 retrial queues with two different types of primary customers arriving according to independent Poisson flows. In the case of blocking, the first type of customers can be queued whereas the second type of customers must leave the service area but return after some random period of time to try their luck again. The author assumes that the server is unreliable and it has a service-type dependent, exponentially distributed life time as well as a service-type dependent, generally distributed repair time. The necessary and sufficient condition for the system to be stable is investigated. Using a supplementary variable method, the author obtains a steady-state solution for queueing measures, and the transient as well as the steady-state solutions for reliability measures of interest.