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1.
本文研究了单修理工有效利用闲期兼职辅助工作的机器维修模型。这个模型被视为带休假策略的有限源排队问题,利用拟生灭过程的方法,给出了系统在稳态下机器故障数的分布和机器等待维修时间的分布,并将结果与经典的机器维修模型作了比较。  相似文献   

2.
具有批到达的滞后排队系统分析   总被引:1,自引:0,他引:1  
本文考虑一个基本模型的M^[x]/G^[r]/1/∞的排队系统,引入了(r,N)-策略(也称为滞后系统),首先分析了嵌入马氏链{Qn,n∈N}的平稳分布,得到其概率母函数P(z),再利用半再生过程理论得到原系统的稳态队长分布的概率母函数π(z)。  相似文献   

3.
离散时间服务台可修的排队系统MAP/PH(PH/PH)/1   总被引:5,自引:0,他引:5  
本文研究离散时间可修排队系统,其中顾客的输入过程为离散马尔可夫到达过程(MAP),服务台的寿命,服务台的顾客的服务时间和修理时间均为离散位相型(PH)变量,首先我们考虑广义服务过程,证明它是离散MAP,然后运用阵阵几何解理论,我们给出了系统的稳态队长分布和稳态等待时间分布,同时给出了系统的稳态可用度这一可靠性指标。  相似文献   

4.
带有缓冲器串行生产线的Harris链结构分析   总被引:1,自引:0,他引:1  
本文以随机过程中的一类特殊的Markov链(Harris常返Markov链)为工具,研究离散事件动态系统(DEDS)中的典型情况之一:带有缓冲器的串行生产线.求得了各缓冲器中产品数的联合稳态分布,产品在各台机器上受阻时间的联合稳态分布,以及受阻时间的强大数定律和产品在各台机器加工完时刻的极限行为.  相似文献   

5.
多服务台可修排队的稳态分布存在条件   总被引:1,自引:1,他引:0  
本文分析多服务台可修排队系统的稳态分布存在条件。多服务台可修排队系统可利用拟生灭过程理论处理。拟生灭过程方法给出了矩阵形式的多服务台可修排队系统的稳态分布存在条件。本文由这一矩阵形式的稳态分布存在条件导出具有明显概率意义的稳态分布存在条件的另一种形式,从而证明了两种不同形式的稳态分布存在条件的一致性。  相似文献   

6.
推广的单重休假M~x/G/1排队系统   总被引:2,自引:0,他引:2  
研究了服务前需要重新调整机器的单重休假Mx/G/1排队系统,在LS变换和L变换下得到了服务员忙期中队长的瞬态分布和队长稳态分布的概率母函数.  相似文献   

7.
系统地研究了两个不同并行服务台的可修排队系统MAP/PH(M/PH)/2,其中两个不同的服务台拥有一个修理工.若其中一台处于修理状态,则另一台失效后就处于待修状态.利用拟生灭过程理论,我们首先讨论了两个服务台的广义服务时间的相依性,然后给出了系统的稳态可用度和稳态故障度,最后得到了系统首次失效前的时间分布及其均值.  相似文献   

8.
考虑生产商、销售商联合库存的动态优化问题,建立的随机需求下生产-销售运作系统的排队模型,得到了系统的稳态概率分布和队长分布.以成本最小化为目标,模型算法找到了最优的运作策略和机器使用数量.数值模拟的结果表明,依赖于指定机器数量的动态调整策略明显优于静态系统.  相似文献   

9.
一类向量高斯过程之上穿过点过程的渐近分布   总被引:3,自引:0,他引:3  
{X(t),t≥}为p维高斯过程,在一定条件下,本文得到了{X(t),0≤t≤T}对水平UT(>0)的ε-上穿过次数所形成的点过程的渐近分布(T→∞)。证明了P个分量点过程的渐近独立性。  相似文献   

10.
研究了具有不耐烦顾客的M/M/1休假排队系统,其中休假时间服从位相分布.当顾客在休假时间到达系统,顾客则会因为等待变得不耐烦.服务员休假结束后立刻开始工作.如果在顾客不耐烦时间段内,系统的休假还没有结束,顾客就会离开系统不再回来.建立的模型为水平相依QBD拟生灭过程,通过利用BrightTaylor算法得到系统的稳态概率解.同时还得到一些重要的性能指标.最后通过数据实例验证了我们的结论.  相似文献   

11.
A continuous revies (s, S) inventory system with renewal demand in which one item is put into operation as an exhibiting piece is analyzed. The lifetime of any operating unit has Erlangian distribution, and on failure is replaced by another one from the stock and the failed item is disposed of. Replenishment of stock is instantaneous. The transient and stationary values of inventory level distribution and the mean reorder rate are obtained using the techniques of semi-regenerative processes. Decision rules for optimums andS that minimize the long-run expected cost rate are derived. The solution for a dual model with the distribution of lifetimes and inter-demand times interchanged is also given.  相似文献   

12.
This paper deals with the synchronized stationary distribution of stochastic coupled systems. The response system is constructed to help achieve a synchronized stationary distribution. Firstly, an error system obtained by the drive system and the response system is given and an appropriate Lyapunov function for the error system is constructed. On the basis of the graph theory and the Lyapunov method, some sufficient conditions are proposed to guarantee the existence of a stationary distribution for the error system, which reflects the coupling structure has a close relationship with synchronized stationary distribution. Then, an application to stochastic coupled oscillators is presented and sufficient conditions are obtained to illustrate the feasibility of the theoretical results. Finally, a numerical example is provided to demonstrate the effectiveness of theoretical results.  相似文献   

13.
This paper deals with a multi-class priority queueing system with customer transfers that occur only from lower priority queues to higher priority queues. Conditions for the queueing system to be stable/unstable are obtained. An auxiliary queueing system is introduced, for which an explicit product-form solution is found for the stationary distribution of queue lengths. Sample path relationships between the queue lengths in the original queueing system and the auxiliary queueing system are obtained, which lead to bounds on the stationary distribution of the queue lengths in the original queueing system. Using matrix-analytic methods, it is shown that the tail asymptotics of the stationary distribution is exact geometric, if the queue with the highest priority is overloaded.   相似文献   

14.
研究具有两类顾客排队需求服务的随机库存系统.系统采取(s,Q)补货策略且当库存水平下降到安全库存s时,到达的第二类顾客以概率P得到服务.首先,建立库存水平状态转移方程并通过递推算法求解获得库存水平稳态概率分布和系统稳态指标;接下来,构建库存成本函数;最后,采用数值试验的方法研究该库存系统的最优控制策略并考察系统参数的敏感性.  相似文献   

15.
An inventory with constant demand is considered. The inventory is checked according to a Poisson process and replenished either fully or partially when the stock is below a threshold. We obtained the stationary distribution of the level of the inventory. After assigning several costs to the inventory, we also derived the long-run average cost per unit time. A numerical example is studied to find the optimal values of the checking rate and threshold, which minimize the long-run average cost.  相似文献   

16.
A production system operates at a speed which is a stationary stochastic process. Given the routine control point, the actual accumulated production observed at that point and the deterministic rate of demand, the decision-maker determines the timing of the next control point. The problem is applied to semiautomated production processes where the advancement of the process cannot be measured or viewed continuously, and the process has to be controlled in discrete points by the decision-maker. Since the cost of performing a single control is relatively high, the control should be carried out as rarely as possible but it also has to ensure a preset confidence probability of achieving production output no less than that required. Formulae for determining the next control point for an arbitrary distribution function of the stationary process with a certain autocorrelation function are presented. They depend on the status of the system (shortage or surplus), the relation between the rate of demand and the mean value of the speed, the variance of the speed, and on the confidence level 1-α. A practical numerical example from the mining industry will be given.  相似文献   

17.
A perishable single item production-inventory system is studied in this paper. The objective is to describe a general model in which the production rate, the product demand rate, and the item deterioration rate are all considered as functions of time, and to discuss the optimal production stopping and restarting times which minimise the total relevant cost per unit time. In the general model, demand shortage is allowed, where some of the demand is lost and the rest is backlogged. Popular models, such as the pure inventory system and the zero shortage system, are shown to be special cases of our model. The conditions for a feasible stationary point to be optimal are given. The simplest cases with constant rates of production, demand and deterioration are discussed and shown as illustrative examples.  相似文献   

18.
A disaster inventory system is considered in which two substitutable items are stored for disaster management. In the event of disaster management, a particular product may become stock-out and the situation warrants that a demand for the particular product during its stock-out period may be substituted with another available similar product in the inventory. From the utility point of view, continuous review inventory models are quite appropriate in disaster inventory management. In this paper, a continuous review two substitutable perishable product disaster inventory model is proposed and analyzed. Since the inventory is maintained for disaster management, an adjustable joint reordering policy for replenishment is adopted. There is no lead time and the replenishment is instantaneous. For this model, some measures of system performance are obtained. The stationary behavior of the model is also considered. Numerical examples are also provided to illustrate the results obtained.  相似文献   

19.
In this paper we consider a specific M/G/k group-arrival loss system, under statistical equilibrium and two cases of acceptance policy. In the first case the system works under the partial acceptance policy. Explicit results are obtained for the corresponding stationary distribution, which extend previous relevant results. In the second case, where the system works under the all-or-nothing acceptance policy, a sufficient condition is given for the stationary distribution to have a closed-product form. In both cases customers depart individually, while the joint service time distribution of the accepted members of a group may depend both on its initial and the accepted size plus an additional condition.  相似文献   

20.
An inventory system for perishable commodities (PIS) with finite shelf size and finite waiting room for demands is studied; the maximum shelf life and the maximum waiting time of a demand are assumed to be either constant or exponentially distributed, and the arrival rates for items and for demands are state-dependent. We determine the stationary distribution of the system and derive various kinds of cost functionals that are useful to evaluate the efficiency of the PIS.  相似文献   

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