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一类存贮模型及其最优存贮策略 总被引:3,自引:1,他引:2
当工厂仓库容量有限时,常常需要租借仓库来进行存贮.但是,由于租借仓库的存贮单价通常比自己仓库的存贮单价高,所以不能用经典的经济批量公式来计算,有必要重新进行研究.本文研究了原料仓库和产品仓库容量均有限条件下的定料生产销售存贮问题,建立了相应的存贮模型,给出了最优定料生产存贮策略. 相似文献
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基于不完全信息静态博弈模型,讨论了相互竞争的两厂商在双方都掌握的线性需求函数和一方随机选取的线性成本函数这样的不完全信息情况下实施三度价格歧视的有效性问题,且给出了双方实施三度价格歧视的最优产量,最优价格以及最大利润公式,并把相关结论与基于完全信息静态博弈的三度歧视定价和不完全信息静态博弈的统一定价进行对比,得出了许多重要的结论. 相似文献
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《数学的实践与认识》2013,(23)
研究了一类带跳的非线性随机群体动力学模型的最优收获控制.给出了在外界环境对系统产生影响的条件下带有Poisson跳的随机种群动力学系统;通过随机极大值原理,Hamilton函数及Ito公式,讨论了最优收获控制所满足的充分必要条件,所得到的结论是确定性种群系统的扩展. 相似文献
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考察了白噪声和脉冲信号联合作用下统一混沌系统的随机渐近稳定性问题,得到该随机脉冲系统的比较系统,从而由该确定性比较系统的稳定性得到原随机脉冲系统的随机渐近稳定性.并从理论上得到能使该随机脉冲系统随机渐近稳定的参数取值范围,最后用数值仿真验证了理论结果的正确性. 相似文献
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研究了一类非线性随机种群系统动力学模型的最优生育率控制问题.在加入外部随机因素扰动下,系统模型将会更具有实际意义.针对随机种群系统生育率控制问题,应用It?o公式,相应的伴随方程和变分不等式等经典理论,获得了随机种群系统最优生育率控制所满足的必要条件及其最优性组(由积分-偏微分方程和变分不等式组成).文中得到的结论是确定性种群系统的扩展,对随机控制理论具有现实的应用价值. 相似文献
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基于对具接种的确定性SIQR流行病模型的研究,我们引进了随机扰动,建立随机SIQR流行病模型.通过构造Lyapunov函数,运用Ito公式,得到了随机系统的无病平衡点和地方病平衡点随机渐近稳定的充分条件.进一步猜想当随机扰动的强度较大时,平衡点的稳定性将会被破坏.最后,利用数值仿真验证了所得结论及猜想的正确性. 相似文献
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Brian G. Kingsman 《The Journal of the Operational Research Society》1991,42(9):803-809
This paper shows that under date-terms supplier credit, making explicit the separate effects of carrying cost, the financing and other marginal holding costs, does not invalidate Kingsman's original result that the optimal order quantity is given by an integer multiple of monthly demands, provided the capital investment component of the inventory holding costs is equal to or greater than 30% of the component due to the physical holding of inventory. The analysis is extended to the case when orders of less than a month's demand are optimal. Here it is shown that the order quantity should be an integer fraction of a month's demand, provided that the capital investment component of the inventory holding charge is equal to or greater than one quarter of the component due to the physical holding of inventory. It is argued that these conditions are likely to be satisfied for most if not all practical inventory situations. Combining these results with those of Carlson and Rousseau leads to a simple formula for the general optimal policy. The EOQ can still be expressed as a simple formula, so for practical situations generally there is no need to use the numerical search procedure these authors propose. 相似文献
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J. A. Buzacott 《The Journal of the Operational Research Society》1975,26(3):553-558
The classical EOQ formula assumes that all relevant costs and prices are constant. In this paper it is shown that with inflation the choice of the inventory carrying charge used in the EOQ formula depends on the company's pricing policy. If prices change independently of replenishment order timing the inventory charge should be low and independent of the inflation rate. However, when no "double ticketing" is permitted and the company uses a constant percentage mark up the carrying charge is high and depends on the inflation rate and the mark-up. Only if the company is allowed a fixed monetary margin is the classical result for carrying charge valid. 相似文献
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Ralph D. Snyder 《The Journal of the Operational Research Society》1973,24(1):125-127
Most continuous time inventory models which allow for the stochastic nature of demands usually include a delivery lag. This disguises a close link between deterministic and stochastic formulations of the inventory problem. By assuming that there is no delivery lag a stochastic version of the classical economic lot size model is developed. It yields the traditional square root formula where the constant demand term is replaced by mean demand. 相似文献
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We consider a variant of the economic order quantity (EOQ) model. Mainly, we assume that demand occurs at random, one unit at a time, and is characterized by independent and identically distributed times between two demand epochs. We also assume that the ordering policy is characterized by ordering the same amount whenever the inventory level drops to zero, and a demand occurs. Surprisingly, we show that the optimal order quantity that minimizes the expected inventory cost follows the familiar EOQ formula. 相似文献
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This paper analyzes the bullwhip effect in multi-stage supply chains operated with linear and time-invariant inventory management policies and shared supply chain information. Such information includes past order sequences and inventory records at all supplier stages. The paper characterizes the stream of orders placed at any stage of the chain when the customer demand process is known and ergodic, and gives an exact formula for the variance of the orders placed. The paper also derives robust analytical conditions, based only on inventory management policies, to predict the presence of the bullwhip effect and bound its magnitude. These results hold independently of the customer demand. The general framework proposed in this paper allows for any inventory replenishment policies, any ways of sharing and utilizing information, and any customer demand processes. It is also shown as a special case that sharing customer demand information across the chain significantly reduces, but does not completely eliminate, the bullwhip effect. 相似文献
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Jun Zhang 《Operations Research Letters》2003,31(6):477-482
We consider the problem of managing multi-customer service level requirements when inventory is rationed according to a priority list. We demonstrate that the optimal purchasing quantity for the two-customer problem may be found through a line search. For multi-customer problems, we derive a formula to find a near-optimal purchasing quantity. 相似文献
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Jiang Zhang 《Operations Research Letters》2007,35(4):503-509
This paper develops an exact formula for the fill rate of a single-stage inventory system that uses a general periodic-review base-stock policy. For normal demand, we present a fill-rate expression that uses the standard normal PDF and CDF, and develop two approximations for the fill rate. 相似文献
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This paper deals with inventory control in a class of M/G/1 queueing systems. At each point of time the system can be switched from one of two possible stages to another. The rate of arrival process and the service rate depend on the stage of the system. The cost structure imposed on the model includes both fixed switch-over costs and a holding cost at a general rate depending on the stage of the system. The rule for controlling the inventory is specified by two switch-over levels.Using an embedding approach, we will derive a formula for the long-run average expected costs per unit time of this policy. By an appropriate choice of the cost parameters, we may obtain various operating characteristics for the system amongst which the stationary distribution of the inventory and the average number of switch-overs per unit time. 相似文献
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This paper studies a deterministic inventory model with a stock-dependent demand pattern where the cumulative holding cost is a non-linear function of both time and stock level. When the monetary resources are limited and the inventory manager can invest his/her money in buying different products, it seems reasonable to select the ones that provide a higher profitability. Thus, a new approach with the aim of maximizing the profitability ratio (defined as the profit/cost quotient) is considered in this paper. We prove that the profitability ratio maximization is equivalent to minimizing the inventory cost per unit of an item. The optimal policy is obtained in a closed form, whose general expression is a generalization of the classical EOQ formula for inventory models with a stock-dependent demand rate and a non-linear holding cost. This optimal solution is different from the other policies proposed for the problems of minimum cost or maximum profit per unit time. A complete sensitivity analysis of the optimal solution with respect to all the parameters of the model is developed. Finally, numerical examples are solved to illustrate the theoretical results and the solution methodology. 相似文献
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模糊需求下的库存风险及最优库存决策 总被引:1,自引:0,他引:1
分析了在模糊需求下,按经典库存模型中的经济订货批量和订货周期所导致的库存风险损失。推导了模糊需求下的经济风险函数。给出了风险函数在模糊需求分布下的重心决策方法,在此基础上得到了模糊需求下经济批量的修正公式,为模糊库存风险分析的研究提供了一种方法。 相似文献