短缺量滞后供给与顾客等待时间相关的VMI模型

考虑短缺量滞后供给与顾客等待时间负相关,提出了供应商生产批量用于满足订货商多次订货需求的VMI模型.仿真寻优求得系统唯一最优解,短缺量拖后因子和生产率的灵敏度分析表明,二者对VMI系统库存控制策略的制定有较大影响.当短缺量拖后因子较大时,订货商应提高服务水平,缩短订货周期;当供应商生产率较大时,则应延长订货周期并减少生产周期内的订货次数.     

短缺量拖后率与价格折扣相关变质品VMI模型

考虑短缺量拖后率与订货商给予顾客的价格折扣正线性相关,提出一种需求指数时变的变质物品供应商管理库存模型,研究了供应链最优库存策略。数值仿真和主要参数灵敏度分析表明,订货商在缺货期间向顾客提供价格折扣有利于降低丢单损失和系统库存总成本;当需求增长因子变化时,VMI系统应保持库存控制策略不变;当变质系数和拖后率上限变大时,VMI系统则应保持订货商补货次数和价格折扣不变,同时适当降低订货商服务水平。     

基于VMI的医院供应管理

医院大部分药品及相关用品属于易逝品,针对该类产品的特点,将VMI(Vender Managed Inventory)方法引入到医院供应管理研究中,通过建立两级供应链库存定量模型(即供应商-医院关系模型),比较实施VMI方法前后,医院、供应商以及供应链总库存成本的变化情况.通过定量比较证实,实施VMI方法可以有效降低医院及供应链总库存成本,供应商的库存成本虽有所升高,但是可以通过转移支付方法,使供应商与医院达到利益均衡点,从而降低供应链总库存成本,获得pareto均衡.     

时滞变质物品库存与运输联合优化模型

针对一类有保鲜期的易腐品——时滞变质物品,考虑需求受价格、广告投入及存货陈列量的影响,在允许缺货和不同的短缺量拖后率下建立该类物品的库存与运输联合优化模型,并针对模型特点设计出一种启发式算法,从而得到最优库存策略及运输策略。给出算例,利用MATLAB7的最优化求解功能容易求出模型的最优解。结果表明:引入由价格、广告和存货陈列量共同决定的需求率,不仅更符合实际,而且有利于将复杂模型转化为关于多项式的问题来处理,大大降低了求解难度,同时节约了求解时间。     

Weibull分布变质物品库存模型研究

研究了变质物品在考虑资金时间价值时的经济订货批量问题.假定物品的变质率服从两参数的Weibull分布,物品的需求率与库存水平有关,且为库存水平的线性函数,计划时域内进行多次订货,订货时间间隔相等,允许缺货且短缺量完全拖后,以库存系统的总费用最小为目标函数,建立了变质物品在存货依赖性需求下考虑资金时间价值时的最优订货批量模型,分析了模型存在唯一的最优解的必要条件,并且给出了在该条件下求解模型最优解的算法,最后给出了一个计算实例.     

具有激励机制的VMI系统Stackelberg博弈

一般供应商管理库存(VMI)模型没有考虑激励机制问题,而订货商的激励政策对供应商管理库存的成本分担有很大影响。考虑订货商对管理库存的供应商采取一定的激励政策,建立了一个生产型供应商和一个销售型订货商构成的二级供应链VMI系统的Stackelberg博弈模型。通过博弈最优解、算例和主要参数的灵敏度分析,表明:激励机制对供应商的努力程度和双方利润有较大影响,激励政策与双方库存成本的分担有密切关系。     

分散协调VMI&TPL模式下的补货决策

提出分散协调供应商管理库存(VMI)与第三方物流(TPL)集成供应链管理模式。与传统VMI不同,该模式下的供应商拥有库存决策权,但将物流具体作业外包给TPL。从供应商角度出发探讨了该模式下的补货决策问题。本模型引入供应商与制造商之间的需求信息共享,同时考虑供应商与TPL之间的运费契约,运费是与补货量有关的分段函数。供应商根据制造商滚动计划期内的需求量、运费契约以及制造商线边仓库的存储能力等进行补货决策。通过将模型转化为动态网络规划问题,分析了模型的计算复杂性。由于该模型问题是NPC问题,给出了模型的模拟退火遗传算法。算例验证了模拟退火遗传算法解决该问题的有效性。     

VMI进行卡尔多-希克斯改进必要性研究

考虑需求放大、订货及库存成本变动等因素,构建完全竞争市场条件下的VMI模型,进行解析分析和仿真求解,证实了供应商管理库存策略进行卡尔多-希克斯改进的必要性。运用灵敏度分析,确定了影响上游企业参与VMI的重要因素,并得出越是优秀的上游企业参与VMI的积极性反而较低的结论。     

BASS预测模型与库存控制集成研究

根据短生命周期产品的特征调整BASS扩散模型,并将其应用于短生命周期产品的需求预测,同时考虑产品需求对无形变质和短缺拖后量的影响,进而建立短生命周期产品多周期订货模型。通过算例分析获得短生命周期产品的成熟期开始时间和持续时间,进而求订货次数和订货量,给出多周期最优订货策略。数据实验结果显示基于BASS需求函数的库存控制模型可以提高需求预测精确度,有效降低库存成本,对企业库存控制具有指导意义。     

碳限额政策下库存运输可持续水平集成优化

基于分散协调和集中控制供应商管理库存(vendor-managed inventory, VMI)供应链,构建碳限额政策下库存运输可持续水平集成优化模型,研究碳限额政策对可持续供应链性能的影响。运用Stackelberg方法构建供应链博弈模型,并在Matlab中模拟实施碳限额政策前后可持续水平优化决策过程。为了调节供应商和零售商之间的溢出效应,设计基于收益共享契约的供应链协调策略。研究结果表明,碳限额政策能提高库存和运输可持续水平,但对服务水平没有影响;集中控制VMI供应链总利润随碳限额单调递增,而分散协调VMI供应链总利润则随碳限额呈先升后降的变化趋势;无论实施碳限额政策与否,集中控制VMI供应链总利润和可持续水平均大于分散协调VMI供应链。     

A discrete transfer function model to determine the dynamic stability of a vendor managed inventory supply chain

This paper considers a well-established production and distribution scheduling algorithm, called the Automatic Pipeline, Inventory and Order Based Production Control System (APIOBPCS) within a Vendor Managed Inventory (VMI) supply chain. It develops a transfer function model of the system using causal loop diagrams, block diagrams, difference equations and z -transforms. Important insights into the VMI supply chain are derived from the mathematical model pertaining to the stability and robustness of the VMI system. Analysis confirmed by dynamic simulation clearly demonstrates instability arising from poor design. We also demonstrate its avoidance via our recommended parameter settings for tuning the two feedback loops within the supply chain for a specific production delay. The procedure is readily extended for other production delays and distributions.     

Designing and computing optimal policies on a production model for non-instantaneous deteriorating items with shortages

This paper discusses a production model for non-instantaneous Weibull deteriorating items with complete backlogging over an infinite time horizon and also extended to the finite time horizon. The model is studied under the production policy starting with shortages. The objective of this model is to minimise the total cost to the manufacturer which is the sum of the setup cost, production cost, holding cost and shortage cost. Finally, numerical examples are given to illustrate the real-life applications of the proposed model. Sensitivity analyses of the major inventory parameters are carried out. Some useful managerial applications are obtained by using sensitivity analysis.     

Decision support system for vendor managed inventory supply chain: a case study

Vendor-managed inventory (VMI) is a widely used collaborative inventory management policy in which manufacturers manages the inventory of retailers and takes responsibility for making decisions related to the timing and extent of inventory replenishment. VMI partnerships help organisations to reduce demand variability, inventory holding and distribution costs. This study provides empirical evidence that significant economic benefits can be achieved with the use of a genetic algorithm (GA)-based decision support system (DSS) in a VMI supply chain. A two-stage serial supply chain in which retailers and their supplier are operating VMI in an uncertain demand environment is studied. Performance was measured in terms of cost, profit, stockouts and service levels. The results generated from GA-based model were compared to traditional alternatives. The study found that the GA-based approach outperformed traditional methods and its use can be economically justified in small- and medium-sized enterprises (SMEs).     

梯形需求缺货部分拖后的变质物品EOQ模型

研究了变质物品在一般梯形需求率下和缺货部分拖后时的库存模型.假定变质物品的需求为一般形式的梯形需求率函数,允许缺货且缺货部分拖后,缺货拖后率是到达下一周期补货等待时间的凹函数,物品的变质率为一般形式的Weibull时变函数,根据一般梯形需求函数不同的参数取值,建立了不同情形下变质物品的库存决策模型,给出了每种情形下模型的最优订货策略.研究结果表明,库存系统最优库存减少为零的时刻不依赖于具体的需求参数,但库存系统的最优订货策略却依赖于具体的需求参数.     

供应链管理中VMI系统的研究

通过分析VMI和RMI在概念原理上的本质差异,讨论了VMI在管理思想、决策方式、预测体系、补货模式、延迟策略方面的优越性和先进性。在此基础上,详细描述了VMI工作流程中的八个关键环节,并结合实际指出实施VMI的步骤和注意事项,最后总结了VMI在实践中给供应商、零售商以及供应链整体带来的收益和竞争优势。     

A green vendor-managed inventory analysis in supply chains under carbon emissions trading mechanism

One of the most important strategies for reducing carbon emissions is to optimize firms’ operation decisions in business practices. This paper proposes a green vendor-managed inventory (a green VMI) model with a supplier and a manufacturer under a carbon emissions trading mechanism. The proposed model integrates both environmental and economic goals under a carbon emissions constraint, and then the members’ optimal decisions are obtained. Comparing this model with the traditional VMI model, this paper finds that, in the green VMI model, whether the supplier should sell or buy carbon credit depends on the carbon cap. Further, the impacts of the carbon cap and the carbon emissions factors on the optimal decisions, the carbon emissions, and the total costs in the supply chain are examined analytically. Finally, numerical experiments are performed to verify the theoretical results. It is shown that, after introducing the carbon trading mechanism, the VMI model could increase the total cost of the supply chain under some specified set of parameters.     

Two-critical-number control policy for a stochastic production inventory system with partial backlogging

This paper deals with a production–inventory control model with partial backlogging, in which a reflected Brownian motion governs the inventory level variation. We consider a single storage facility with infinite capacity and assume that shortages are allowed and the total amount of stock-out is a mixture of backordering and lost sales. In addition, the production facility is controlled by a two-parameter (m, M) policy, which switches the production rate when the inventory level reaches the threshold values. The aim is to determine the optimal control parameters m and M by minimising the long-run total expected cost of the system. Some results are illustrated using numerical examples. A sensitivity analysis of the optimal solution with respect to major parameters is also carried out.     

跨境VMI供货模式下生产-库存联合优化研究

研究基于跨境VMI(vendor managed inventory)供货模式下的生产-库存联合优化问题。以一个实际案例企业作为应用背景,比较了VMI供货模式和传统的供货模式在海运和空运2种运输方式下的不同特点及其对决策的影响。研究结果表明,对于案例企业而言,采用VMI供货模式的库存管理是可行的,考虑目前公司采用2种可选的运输模式,选择海运的总成本最低。通过对资金费用率、库存费用比率和缺货费用率进行灵敏度分析,探讨了不同环境变量对最优决策的影响。研究结果对跨境供应链多国生产型企业改善跨境物资采购和生产-库存决策有一定参考价值。