策略在二级库存管理中的应用

分析了二级库存管理系统中,在特定假设条件下,采用策略制定销售商和供应商的最优库存决策,并对不同周期下供应链的库存成本进行了分析。     

需求受价格和库存影响的非立即变质物库存模型

对于非立即变质类的物品,考虑它的需求率同时受价格和库存的影响,当库存大于一定量时,需求只受价值影响;小于一定量时,需求同时受价格和库存影响.在不允许缺货,且补充率为无穷的情况下,建立了单周期的库存模型,证明了其最优解的存在性,并给出了寻求最优库存策略和最优销售价格的方法.     

基于预防检查的安全库存生产策略

基于会随机发生失控的不可靠生产系统,研究了允许缺货情况下,考虑预防检查结果对安全库存的影响.根据一个完整周期的生产过程,分析了生产过程中的费用组成,建立了考虑预防检查和安全库存的EMQ模型,以求得使单位时间内总费用最小的最优安全库存量、正常生产时间.最后,通过数学案例,总结了模型中参数的变化对决策变量和目标函数的影响.研究结果表明:随着劣化率的增大,单位时间内总费用增加,最优安全库存量增加,正常生产时间减少.     

〈T，S〉策略在二级库存管理中的应用

分析了二级库存管理系统中，在特定假设条件下，采用＜T，S＞策略制定销售商和供应商的最优库存决策，并对不同周期下供应链的库存成本进行了分析。     

带有两仓库需求时变的变质性物品的补货策略

在两仓库的情况下,讨论了需求率时变、变质率为常数的单一变质性物品在允许延期付款但不允许缺货且给予顾客一个信用期情况下的库存策略,证明了最优补货周期的存在性,并给出了求最优补货周期的算例。     

批量处置下逆向物流运作中销售商库存优化控制数学模型的构建

以销售商对逆向物流退回产品进行批量处置为基础,研究了其库存优化控制问题,将该问题转化为销售商总订货成本最小化时的最优订货周期和最优订货数量求解问题,基于相关假设和参数设定,构建了库存优化控制模型并对该模型进行了算例检验。研究结果表明,随着客户退货强度的增加,销售商的最优订货周期将会相应地延长,而订货成本会相应地降低,在供应链逆向物流实际运作中,销售商可以以批量处置规模效益为目标,根据实际情况对模型的参数进行灵活的掌握,从而有效地实现库存的优化控制。     

药品制剂公司压缩库存保证货源的几点认识

<正>为了减少库存资金占用,降低生产成本,药品制剂公司要求降低库存周期,要求产成品库存周期不能高于2.5个月,没有成品生产计划原辅材料不能提前采购,在原辅材料没有运输到达生产区的情况下,成品的生产周期最少是30天,根据当前公司对库存控制的要求和现在生产周期比较长的现状,如何在总库存量降低的情况下,保证全国二十几个办事处的销售不断货,成为迫切需要解决的问题。这就要求做好三方面的工作,编制好生产计划和预测好产品的销售量,合理地调配货源。     

易变质商品供应链合同研究

以一个零售商和一个供应商组成的两级供应链库存系统为研究对象,在模糊需求假设条件下,建立了供应商在零售商已做决策的条件下的最优库存策略.随后研究了供应链集成库存管理模型,并给出模型的求解步骤.最后通过算例说明供应链集成库存管理能有效的减少库存总成本,并分析了变质率对零售商和供应商订货周期以及变质率对各成本的影响.     

基于多变量多商品库存模型研究

如何确定定货量及定货时间一直以来都是困扰企业库存管理的一个复杂问题,尤其是在涉及多商品库存问题时,多个变量约束使其愈加复杂.本文在满足资源的约束下建立了多商品混合整数规划模型来优化解决上述两个问题,并比较了固定周期和独立周期两种定货方式下的成本来选择最优订购方式.     

快消品行业城区中小零售商最优补货策略研究

以城区中小快消品零售商为研究对象,分析零售商随机需求条件下库存与路径的集成优化问题,提出了最优补货策略及其模型,并确定出基于运输能力限制条件下的零售商最优补货周期和补货成本、区域配送中心的经济库容及安全库存水平。采用最优补货模式后,最大限度地盘活了各自为政时零售商的独立库存,并且实现了配送过程的满载和配送路线的优化,降低了运输和配送成本。最优补货策略为空间有限、网点稠密的城区快速消费品零售商的补货问题提供了可行的解决方案。     

Are all Scales Optimal in DEA? Theory and Empirical Evidence

Policy recommendations concerning optimal scale of production units may have serious implications for the restructuring of a sector. The piecewise linear frontier production function framework (DEA) is becoming the most popular one for assessing not only technical efficiency of operations, but also for scale efficiency and calculation of optimal scale sizes. The main purpose of the present study is to investigate if neoclassical production theory gives any guidance as to the nature of scale properties in the DEA model, and empirically explore such properties. Theoretical results indicate that the DEA model may have more irregular properties than usually assumed in neoclassical production theory, concerning shape of optimal scale curves and the M-locus. The empirical results indicate that optimal scale may be found over almost the entire size variations in outputs and inputs, thus making policy recommendations about efficient scale difficult. It seems necessary to establish the nature of optimal scale before any practical conclusions can be drawn. Proposals for indexes characterizing the nature of optimal scale are provided.     

Uncertain horizon and stability: Analysis in an optimal growth model

In a one-sector optimal growth model with uncertainty about production optimal capital stocks converge in distribution to a stochastic modified golden rule [see, for example Brock and Mirman (1972, 1973)]. We show that such a result cannot be obtained, in general, if in addition to the random one-period shocks to production there is also a lasting shock to the production function at some random date in the future; however, the conditional optimal capital stocks ‘bunch together’ over time, i.e., a turnpike result for optimal programs is proved.     

Economics and operations management: towards a theory of endogenous production speed

A firm chooses the production speed and amount of labor that maximizes profit in a perfectly competitive market. Faster production raises management expenses and the unit cost of production mistakes. Adding workers enhances the division of labor on the production line and raises work‐in‐process inventory. When the division of labor is high, a rise in the wage can increase the optimal production speed and quantity of output. When price falls, optimal production speed and optimal division of labor can move in opposite directions. Output quantity can also rise, generating a downward sloping supply curve in the absence of increasing returns to scale. Copyright © 2002 John Wiley & Sons, Ltd.     

考虑延期成本承诺交货时间与产能扩张决策

根据产能与交货时间的关系,构建了延期成本函数。在此基础上,建立以企业利润为目标函数,以承诺交货时间和产能扩张为决策变量的模型。通过模型的分析得到了相互递推的最优承诺交货时间和最优产能扩张关系式,以及联合最优承诺交货时间和产能扩张。最后通过算例分析表明企业利润随着承诺交货时间或产能扩张的增加先增加后减少,两者相比,企业利润受承诺交货时间影响更大。     

On the optimal size of Social Security in the presence of a stock market

The paper develops a stylized overlapping generations economy with random production and a stock market. The impact of a Social Security system on production, asset markets, and consumer welfare is analyzed. It is shown that any reduction in the contribution rate fosters capital accumulation and increases asset prices, wages, and production output. Different welfare criteria are applied to determine the optimal size of Social Security. It is shown that there exists a unique contribution rate which is long-run optimal, socially optimal, and time-consistent in the sense that no generation has an incentive to change it.     

A Bayesian approach for exact optimal measurement and cutting times for a Eucalyptus production forest

This paper addresses the design for supporting the optimal decision on tree cutting in a Portuguese eucalyptus production forest. Trees are usually cut at the biological rotation age, i.e. the age which maximizes the yearly volume production. Here we aim the maximization of the long-term yearly volume yield reduced by harvest costs. We consider different growth curves, with a known prior distribution, that can occur in each rotation. The optimal cutting time at each rotation depends both on the current growth curve and on the prior distribution. Different priors and strategies are compared with respect to the long-term production. Optimization of the cutting time allows an improvement of 16% of the long-term volume production. We conclude that the use of optimal designs can be beneficial for tree cutting in modern production forests.     

原料有批量折扣的生产库存模型

研究了原料价格有多种批量折扣,生产商进行批量采购,且每次生产至少采购一次;需求率与生产成本固定的条件下,生产商的最优采购策略及最优生产批量问题。模型的求解一般需要分两个阶段:首先初步求出可能的最优采购批量与可能的最优生产批量,并由此得出可能的采购次数,而后求出各采购次数条件下各采购策略下的总成本,其中令总成本最低者即为所求。给出了一个算例对模型进行了说明。     

Responsibility accounting and asymmetry of information

This paper uses the principal-agent model to show that a manager's optimal compensation should generally include non-controllable factors of production such as the firm's investment in capital. This implies that the managerial accounting distinction between profit and investment centres is artificial. Examples are shown in which the ROI or RI criteria could be optimal for compensating managers implying that the optimal compensation criterion is very much specific to the firm's production and risk parameters. Thus, the debate about which criterion is more appropriate is vacuous.     

Age-specific dynamic labor demand and human capital investment

To study the optimal age-specific labor demand and human capital investment at the firm level we extend the standard dynamic labor demand model by introducing ‘age’ as a second dynamic variable and distinguish between two types of workers: ‘low skilled’ and ‘high skilled’. Applying an age-structured optimal control model we derive qualitative features of the optimal age-specific hiring and training effort. For the case of a linear revenue and production function we prove that firms do not anticipate changes in adjustment costs in their optimal decisions. This result no longer holds if a nonlinear revenue or production function is considered.     

An entry/exit decision for transnational production system: applying optimal financing behavior

This study introduces the real options approach to construct the decision model of entry (exit) in flexible transnational production systems. The firm value is appraised under the external financing behavior to solve the optimal cross-border financing ratios by transnational production systems. The proposed approach can evaluate effectively the potential investing value before project adopting, invested project value, potential disinvesting value, and salvage of abandon under matching the multinational enterprises financing behavior. How to decide the optimal cross-border financing ratios of the investing operation and disinvesting salvage timing is the point of the research in making of production system entry and exit.