考虑处置和延迟交货的混合系统库存决策

对存在旧产品处置和采用延迟交货策略的混合系统库存决策问题进行研究。在混合系统中,有制造与再制造两种产品供应模式。产品使用后从顾客处返回,但因再制造能力的不足,返回的旧产品仅有部分用于再制造,其余的被处置。旧产品通过再制造得到再制造品,原材料和零部件通过制造得到制造新品,再制造品具有与制造新品完全相同的质量。可翻新品库存由用于再制造的旧产品组成,服务性产品库存由制造新品与再制造品组成。顾客的需求恒定且由服务性产品来满足,允许缺货但需完全拖后补足。利用（P,1）策略构建库存决策模型,给出了确定最优制造与再制造策略的求解方法,得到了制造和再制造准备次数、制造和再制造批量、模型周期长度、制造与再制造期的最大缺货量等决策变量的求解公式。算例表明,可以找到最优的制造与再制造策略。     

混合系统随机库存决策研究评述

混合系统包含了制造与翻新两种产品供应模式、可翻新品库存与服务性产品库存两类产品库存,加上混合系统中旧产品数量、质量和返回时机等不确定性的影响,这些使得混合系统的库存决策比传统生产系统的复杂和困难.由于旧产品翻新能够实现原料、能量附加值和劳动附加值的循环利用,降低生产成本.因此,对混合系统进行研究具有重要的现实意叉.本文首先给出了混合系统的定义、库存决策分类的依据,然后分别对确定最优策略结构和最优策略的混合系统随机库存决策模型的相关研究进行评述,最后针对当前研究的不足,将降低混合系统库存决策不确定性、拓展现有的随机库存决策模型、开发新的确定控制参数启发式算法等作为混合系统随机库存决策未来的研究方向.     

产品生态化设计与再造决策

基于再制造的产品生态化设计是生产商应对内外部刺激的关键策略,在市场需求和回收量不确定情况下,产品的制造/再制造系统变得复杂化。从生产商以生产总成本最小化为决策目标,建立了数学模型并求解得到了产品生态设计率、普通产品的回收再造率和生态产品的再造率等三个决策变量的最优值。通过数例进行计算并且分别基于12种成本参数进行敏感性分析。结果表明,生产商对于决策变量具有较强的策略性选择。     

考虑紧急订货的供应链库存控制策略研究

库存控制的研究一般只考虑正常订货的情况，但实际上紧急订货经常出现。供应链库存控制策略的制定时，上游厂商为下游厂商的紧急订货准备一定量的产品，可以减少缺货损失，降低成本。本文在分析了考虑紧急订货的供应链库存控制成本的基础上，提出了关于最优策略的数量模型，并给出了求取最优解的方法。     

供应链多级库存控制应用研究

库存是连接制造企业供应链的纽带,如何设置和维持一个合理的库存水平,以平衡存货不足带来的短缺风险和损失,以及库存过多所增加仓储成本和资金成本成为一个制造企业必须解决的问题,文章在多级库存控制理论基础上,提出了两种多级库存策略,一是基于成本优化的多级库存策略;二是基于时间优化的多级库存策略。     

供应链中断对制造商库存策略的影响分析

研究了在供应中断情况下,制造商库存系统的订货提前期与外部系统、订货成本、惩罚成本之间的关系。结果表明,最优库存策略对供应中断持续时间更加敏感。     

风险偏好的供应链再制品生产和定价决策问题研究

本文通过建立一个由制造商、再制造商和零售商组成的二级供应链,分别研究了再制造商和制造商不同风险厌恶程度下供应链的最优决策问题。结果表明：新产品市场容量扩大时,再制造商应实施扩大生产的策略,而不是调整价格策略;制造商再制品生产成本的增长会损害再制造商的利益;制造商再制品处于市场扩张期间,再制造表现出较高的风险厌恶水平时更有利;风险厌恶型再制造商产品的批发价格高于风险中性型再制造商产品的批发价格;再制造商再制品生产成本较高时,制造商应显示出较低的的风险厌恶程度。     

中国邮政包裹业务用户让渡价值影响因素的实证研究

利用以北京高校大学生为调研对象的问卷调研数据,基于顾客让渡价值理论,采用结构方程模型,构建了中国邮政包裹业务顾客让渡价值影响因素分析模型。研究表明:产品价值和服务价值的实现有助于提高顾客总价值;服务价值和人员价值的提高能使邮政包裹业务的形象价值得到提升;人员价值和形象价值对顾客总价值没有太大影响;顾客总成本受货币成本和体力成本的影响;时间成本通过影响货币成本间接作用于顾客总成本。     

基于科技进步的供应链管理研究

分析了科技进步对供应链管理的两方面的影响:信息化技术减少订单成本;先进生产技术提高生产质量.建立了供应商和顾客一体化的库存模型,同时决策最优的订货量、运输批次、订单成本和生产质量,使总成本最小,并给出最优解的求解算法.运用数值算例说明减少订单成本和提高生产质量对供应链管理的影响.     

浅析制定仿真模型对库存管理的作用——以血液库存控制模型分析为例

血液库存系统的随机性特征使得采用数学方法求解其订货点、安全库存十分困难.而根据采血科和供血科提供的相关数据,对血液供需的随机性进行分析,利用产品补给服务水平与安全库存的关系,建立了一个离散事件仿真模型,通过模型中相关参数的设置,运用witness仿真平台,研究各种情况下的血液库存状况,得到库存控制模型;使用函数关系和建立的仿真模型在需要争供给规律变化的情况下,只需要重新统计模型中参数,再次运行模型来确定新情况下的库存策略,则可以为管理者提供一个长期有效的科学方法.     

Analysing remanufacturing decisions of supply chain members in uncertainty of consumer preferences

This article formulates a gaming model of the closed-loop supply chain with manufacturers (as the leader), sellers and consumers where consumers may or may not be willing to pay remunerative price for remanufactured products vis-à-vis new products. In the model, manufacturers produce new as well as remanufactured products, whereas sellers distribute them. In stable circumstances, this article presents the functional formula of the optimal manufacturing pricing decisions. The results show that when the cost of new products is significantly lower than that of remanufactured ones, manufacturers choose to produce new products only. When the difference between cost of new and remanufactured products is moderate, manufacturers tend to produce both new and remanufactured products, and in some regions, production of new and remanufactured products is proportional to each other. When the difference between cost of new and remanufactured products is enormous, their production and sale tend to stop. Also, this article analyses the effects of varying cost of new and remanufactured products and the recycling rate on pricing decisions of supply chain members. This article contributes to the management of manufacturers’ and sellers’ remanufacturing decisions and also provides advice on how governments can guide consumer preferences.     

Integrating dynamic pricing and inventory control for fresh‐agri product under consumer choice

In this article, we investigate a joint pricing and inventory problem for a retailer selling fresh‐agri products (FAPs) with two‐period shelf lifetime in a dynamic stochastic setting, where new and old FAPs are on sale simultaneously. At the beginning of each period, the retailer makes ordering decision for new FAP and sets regular and discount prices for new and old inventories, respectively. After demand realisation, the expired leftover is disposed and unexpired inventory is carried to the next period, for continuing selling. Unmet demand of all FAPs is backordered. The objective is to maximise the total expected discount profit over the whole planning horizon. We present a price dependent, stochastic dynamic programming model taking into account zero lead‐time, linear ordering costs, inventory holding and backlogging costs, as well as disposal cost. As the influence of the perishability, each customer selects his preferred choice based on the utility of product price and quality. By the way of constructing demand rate vector, the original formulation can be transferred to be jointly concave and tractable. Finally, we characterise the optimal policy and develop effective methods to solve the problem. We also conduct numerical studies to further characterise the optimal policy, and to evaluate the loss of efficiency under static policies when compared to the optimal dynamic policy.     

基于高新表面技术的再制造产业发展初探

本文对高新表面技术在发动机再制造产业发展中的作用进行了初步研究。结果表明,运用高新表面工程技术可以使旧发动机中62%的失效零件得到修复,而且修复后的表面性能优于新品。先进表面工程技术在发动机再制造中的应用提高了废旧品利用率,降低了再制造成本,不仅使企业获得了经济效益,还为国家节能、节材、保护环境做出了贡献。研究结果还表明,以再制造方式实施发动机整机水平的循环利用,其节能效益和环境保护效益最佳,再制造1万台废旧发动机可节约电1．45×10~8 kWh,减少CO_2排放0．6 kt,同时,可使发动机的旧部件回收利用率由72．3%提高到90%。     

Optimal procurement strategies by reverse auctions with stochastic demand

This paper studies a dynamic procurement problem by reverse auction for a retailer with stochastic demand. In each period, the retailer based on his inventory needs to determine a payment function (a procurement contract) according to which a number of potential suppliers compete in the reverse auction. We show the existence of the retailer's optimal payment function and find that the suppliers' Bayesian–Nash equilibrium bidding strategy is similar to the base-stock policy in the traditional multi-period inventory control problems when the retailer incurs no fixed setup cost, while similar to the (s, S) policy when the retailer incurs a fixed setup cost. This strategy is for the suppliers, instead of for the retailer, depends on the supplier's marginal cost and so is stochastic for the retailer. Thus, this paper extends well beyond traditional procurement environments studied so far in the inventory control literature.     

灰色环境下制造/再制造集成物流网络优化设计

本文考虑到制造/再制造集成物流网络中新产品与再制造产品的需求量和废弃产品质量的不确定性,用灰数来表达网络中的某些参数,从而提出了一种带有灰色参数的制造/再制造集成物流网络优化设计模型。利用灰色白化方法将灰色规划模型转化为确定型的等价类模型,并用优化软件对确定型模型进行求解。最后通过算例验证了网络设计方法的有效性。     

供应商管理库存研究现状及展望

自20世纪80年代宝洁与沃尔玛成功实施供应商管理库存（VMI）以来,VMI开始受到学术界的广泛关注。这种库存管理策略打破了传统的各自为政的库存管理模式,体现了供应链的集成化管理思想,是一种新的、有代表性的库存管理思想。从VMI内涵、VMI效果、VMI与信息共享、VMI运作优化以及利益协调几个方面对VMI的研究进行了文献综述。通过文献研究后发现存在以下不足：①现有的VMI实施效果评价方法过于单一;②需求与提前期均随机的情况研究的不多;③建立成本模型时运输成本设计过于简化;④一对多的VMI利益协调方法还有待于进一步拓展。最后,针对上述研究不足,提出了该领域进一步研究的思路,如可运用系统评价的方法对VMI实施效果评价进行综合评价,可探讨需求与提前期均随机时的VMI运作优化问题等,希望能对该问题的深入研究起到有益的促进作用。     

The Demand for Food Products: An Analysis of Interpurchase Times and Purchased Quantities

In this paper we study household purchase behaviour of storable food products. An inventory model is developed in which the household chooses an optimal stock level of the product. Storage of the product is costly, there is a fixed cost per purchase occasion, and the market price is sometimes discounted because of price promotions. We show that the optimal purchase policy is an s , S policy. The model is used to derive predictions on the correlations between interpurchase times and purchased quantities on the one hand, and prices on the other. These predictions are empirically verified using consumer panel data.     

Long horizon versus short horizon planning in dynamic optimization problems with incomplete information

Summary. This paper compares the implications of short and long horizon planning in dynamic optimization problems with the structure of a standard one-sector growth model if agents have incomplete knowledge about the production function. Agents know the output and rate of return at the current capital stock and use an estimation of the production function based on this knowledge to determine current consumption. For standard utility functions without wealth-effects both long and short planning horizons yield convergence to the steady state - however at a faster rate than optimal -, or fluctuations around the steady state, and in both cases, long horizon planning yields a policy which locally at the steady state is closer to the optimal one than short horizon planning. On the other hand, for preferences with wealth effects where the intertemporal optimal path exhibits fluctuations, long horizon planning destabilizes the path and short horizon planning can generate paths which are qualitatively closer to the optimal one and yield higher discounted utility.Received: 5 April 2001, Revised: 15 September 2003, JEL Classification Numbers: C61, D83, D90.Herbert Dawid: The author would like to thank Richard Day for numerous stimulating discussions which led to this article and an anonymous referee for helpful comments     

SWITCHING COST AND DEPOSIT DEMAND IN CHINA

This article develops and estimates a dynamic model of consumer demand for deposits in which banks provide differentiated products and product characteristics that evolve over time. The switching cost is 0.8% of the deposit's value, which leads the static model to bias the demand estimates. The dynamic model shows that the price elasticity over a long time horizon is larger than the same elasticity over a short time horizon. Counterfactual experiments with a dynamic monopoly show that reducing the switching cost has a comparable competitive effect on bank pricing as a result of reducing the dominant position of the monopoly.