Analysis of stability and bullwhip effect in production-inventory systems

To discuss the relationship between stability and bullwhip effect in the supply chain system,a basic model in a production-inventory control system is developed using difference equations.Z-transform techniques are applied to investigate the production ordering and inventory dynamics.For the two operational regimes of sufficient inventory coverage and insufficient inventory coverage,the scope of decision parameters which make the system stable or instable is investigated.Under two operational regimes and the actual system,production release rates,stability/instability and bullwhip effect in the stable region and instable region are examined based on different demand functions,and then the numerical simulation results are given.The results show that reasonable choices of fractional adjustment of inventory and supply line can make the system stable and decrease bullwhip effect.It is summarized that the piecewise linearization based on the stability analysis approach is a valid approximation to the analysis of production-inventory ordering systems with nonlinearities.Some interesting results are obtained and they have important implications for improving inventory and order decisions in supply chain systems.

Vendor managed inventory and bullwhip effect

This paper studies that the bullwhip effect of order releases and the amplifications of safety stock arise within the supply chain even when the demand model is ARIMA(0, 1, 1) and the forecast method used is a simple exponentially weighted moving average. It also examines a vendor managed inventory (VMI) program to determine how it can help alleviate such negative effects, and gives the theoretical proofs and numerical illustrations. The results show that the effects with VMI are better than the effect without VMI in demand forecasting and safety stock levels, etc.

供应链管理中的牛鞭效应(Bullwhip Effect)现象研究——以图书供应链为例

基于国内外对BullwhipEffect现象的研究现状,分析了我国图书供应链中普遍存在BullwhipEffect现象的原因及其危害性。

Impact of Sophisticated Stationary Forecast Techniques on the Bullwhip Effect in a Supply Chain

The bullwhip effect in a multistage supply chain was analyzed using sophisticated stationary forecasts (third order moving average and third order exponential smoothing forecasts). The third order exponential smoothing and third order moving average forecasts sometimes have a variance reducing effect on the supply chain.In a supply chain with positively correlated or independent and identically distributed (i.i.d) demands, the order variance based on simple moving average forecast (or simple exponential smoothing forecast) is larger than the order variance based on second order moving average forecast (or second order exponential smoothing forecast),and the order variance based on second order moving average forecast( or second order exponential smoothing forecast) is larger than the order variance based on third order moving average forecast( or third order exponential smoothing forecast). In addition, for i.i.d demands, third order exponential smoothing forecast leads to a larger variation than third order moving average forecast.

Comparing the bullwhip effect under different inventory policies in engineering project supply chains

Measuring bullwhip effect is useful for making better controls on production planning and enhancing the supply chain operating efficiency.First,this article establishes the comparative analysis model of bullwhip effect between(s,S)and Periodic Review(PR)inventory policy based on the quantitative bullwhip effect model under different inventories.Then,the impacts of lead time,inventory review time,autocorrelation coefficient,and the number of samples on the gap of bullwhip effect under(s,S)and PR IP are analyzed.The results show that bullwhip effect in PR is more intense than(s,S)inventory policy.Contractors should pay more attention to control bullwhip effect when adopting PR inventory policy to enhance the total operating efficiency of the engineering project supply chains.

Applying IT to Avoid Bullwhip Effect of Supply Chain

Bullwhip effect is the most important factor considered in the supply chain management. It gets many scholars＇ attention that bullwhip effect has been restricting the development of the supply chain all the time. Information Technology （IT） can reduce bullwhip effect by sharing the information among the enterprises in the supply chain.

Study on the Complexity of the Bullwhip Effect

Recent years have witnessed a rapid growth of interest in the study of the dynamic behavior of replenishment rules of bullwhip effect. We prove that bullwhip effect and butterfly effect share a same the self-oscillation amplifying mechanism that is the ordering decisions the supplier self-oscillation amplify the perturbations brought by the errors in the processing of retailers' demand information. This results as an explicit self-similar structure of the sensitivity of the system to the initial values duty to the nonlinear mechanism. In this paper, the causes process of the bullwhip effect is described as the internal nonlinear mechanism and study on the complexity of bullwhip effect for order-up-to policy under demand signal processing. The methodology is based on fractal and chaotic theory and allows important insights to be gained about the complexity behavior of bullwhip effect.

A Study of the Bullwhip Effect for Short Life Cycle Products in Supply Chain Management

Shorter product life cycles present new dressed in supply chain literature. This research challenges to managing production and logistics not adequately adaddresses issues pertaining to the management of supply chains in a short life cycle environment. In this paper, we study the short life cycle environment; then we develop the ventory policy of the indirect manufacturer by explicitly using his demand us an output of the retailer＇s optimal inoptimal ordering policy. Finally, we also provide causes of the bullwhip effect in the context of short life cycle products.

Coping with the Bullwhip Effect Using Inventory or Cash: An Environment-Behavior-Performance Paradigm

The bullwhip effect is w idely found in business and exerts adverse effects on business activities.To investigate the influence of the bullwhip effect on firm s'performance and their responses,this study proposed an environment-behavior-performance analysis fram ework and offered a new perspective for studying the bullwhip effect.Using data collected from 1,734 listed manufacturers in China from 2002 to 2017,we adopted regression models to test the proposed m odel and conducted a series of robustness tests.We find that the bullwhip effect is positively related to operating risk,inventory,and cash holdings,and the moderate levels of inventory and cash are negatively associated with operating risk.Specifically,inventory and cash play different roles and work together to alleviate operating risk induced by the bullwhip effect.However,excess resource holdings are positively associated with operating risk.Therefore,firm swith different levels of resources should hold suitable levels of inventory,cash,or both as contingent responses to the bullwhip effect.

产能中断下汽车供应链牛鞭效应的系统动力学仿真

在突发事件的影响下,市场供给不确定性逐渐增加,供应链中出现产能中断与信息不对称等问题,导致供应链出现牛鞭效应。因此,基于系统动力学对汽车供应链进行仿真分析,设计存量流量图,分析订单完成情况与各节点库存量变化,并对影响供应链牛鞭效应的变量进行因果分析。结果表明,安全库存量的增加和转运时间的减少可以有效减少由中断引起的库存量激增现象,同时提高供应链绩效。

一种基于联邦学习的供应链需求预测方法

供应链需求预测是供应链管理的核心环节,直接影响着供应链的运作效率和成本控制。然而,在不确定的市场环境下,如何提高需求预测准确性一直是供应链管理的难题。尤其是在供应链中,各个企业出于保护自身利益和隐私的考虑,不愿意与其他企业共享自己的需求数据,导致了传统的基于单一数据源的预测方法存在较大的误差和局限性。针对这一问题,本文提出了一种基于联邦学习的供应链需求预测方法。该方法通过构建一个分布式的预测模型,使得供应链中同一层级的企业可以在不泄露自己数据的情况下,利用其他企业的数据来优化自身的预测模型,从而提高预测的准确性和效率。本文通过数值实验与传统方法对比分析,验证了基于联邦学习的供应链需求预测方法在提高预测准确性和缓解牛鞭效应方面的有效性,为供应链管理提供了新的思路和方法。

Methods of vendor managed inventory control in supply chain management

By inducing the typical inventory control problem - the bullwhip effect, this paper presents vendor managed inventory (VMI) control methods on the basis of traditional methods of inventory management methods, constructs a VMI mathematics model, and analyzes the influence of VMI on inventory cost and channel profit. Finally, a special case is studied to verify that VMI is an effective supply chain strategy that can not only increase channel profit of supplier and customer but also improve full channel coordination, thereby reducing the bullwhip effect.

牛鞭效应与生产平滑模型有效性问题

评述国内外关于牛鞭效应和与之紧密相关的生产平滑模型有效性问题的研究进展,也扼要地叙述作者在这个领域所做的部分工作.作者的工作将国际上对牛鞭效应的研究从特殊时间序列下的两阶段模型拓展到一般ARIMA时间序列下的多阶段模型,并以此为基础分析了需求信息在供应链中传播的一般规律.这些规律的发现扩展了牛鞭效应研究的一些经典结论,揭示了一些新颖现象的存在,并为彻底解决国际学术界长达20年的关于生产平滑模型有效性问题的争论提供了可能.最后,指出几个相关的研究问题,希望中国学者能在这一领域的研究中取得重要突破.

用信息共享抑制供应链中的牛鞭效应

供应链中的牛鞭效应严重影响了供应链管理的运行效率.首先从波动放大和时间延迟两方面阐明了供应链中的牛鞭效应,在此基础上系统地分析了牛鞭效应产生的原因,并提出了相应的缓解对策,最后论述了供应链成员间的信息共享可有效缓解牛鞭效应.

供应链中牛鞭效应问题研究

牛鞭效应对企业的效益甚至整个国家的经济会造成严重的影响,多年来一直受到人们的关注,但直到近年对它才有较为清晰的认识.文章通过文献综述,讨论供应链中牛鞭效应的现象和成因,减轻和消除该效应的对策以及进一步的研究方向.

在ARIMA(0,1,1)需求下的牛鞭效应与信息共享的评价

本文考虑一个包含一个供应商和一个零售商的两级供应链 ,研究在需求模型ARIMA( 0 ,1 ,1 )下牛鞭效应的量化和信息共享的价值 ,比较信息共享之前和之后的差异 ,其结果表明信息共享能给供应商带来减轻牛鞭效应、减少现有平均库存以及降低成本等好处。

需求信息预测与处理中的牛鞭效应

研究了在不稳定的市场需求下,生产商和零售商所组成的供应链系统中的牛鞭效应存在问题.提出了当零售商采用一次平滑指数法或简单移动平均法获得需求信息的过程中,不存在波动放大现象.证明了在生产商和零售商都采用固定间隔库存策略处理需求信息的过程中,显著存在波动放大现象,从零售商到生产商的信息传递过程中,存在着牛鞭效应现象.需求过程中的牛鞭效应主要是由于生产商和零售商利用各自库存策略处理信息的结果.

信息对供应链的影响研究

利用一种简单的供应链模型 ,研究供应链过程中的牛鞭效应。本文的研究显示 ,供应链各成员之间的信息交换和合作可以减少牛鞭效应的负面影响 ,降低制造商的安全库存 ,减少供应链过程中的资源浪费。

基于Anylogic的物流服务供应链牛鞭效应仿真分析

针对当前牛鞭效应研究集中于产品供应链的现状,以及服务的无形性等众多与产品不同的特性,提出以服务能力模拟产品库存进行牛鞭效应研究的可能;构建了物流服务供应链的概念模型,归纳出其牛鞭效应的四个成因;以上下游服务能力调配策略为基础,构造了三阶物流服务供应链中的成本函数和等待时间函数,运用仿真软件Anylogic进行了实证分析和优化改进。结果表明牛鞭效应确实也存在于服务型供应链中,造成能力利用率偏低和资源浪费,同时验证了以服务能力模拟产品库存进行牛鞭效应研究的有效性。

信息共享下库存量牛鞭效应的影响因素研究

目前的研究多从供应链上游角度出发考虑传统牛鞭效应,而本文从供应链下游的角度研究库存量牛鞭效应得到了不一样的管理学启示.在需求函数方面,建立的需求模型包括市场规模、价格敏感性系数等更有现实意义的要素.在此,本文建立了包括一个零售商和一个制造商的简单两级供应链,得出了制造商在采用补充至订货点策略和最小均方差预测技术,在两种不同的信息共享模式下的库存量牛鞭效应表达式,并对他们的影响因素进行了分析.而且通过数值分析对模型进行了验证并得到新的结果.通过研究发现,信息共享能够显著降低制造商的库存量牛鞭效应;零售商和制造商的库存量牛鞭效应都不受市场规模的影响;零售商的库存量牛鞭效应在一定条件下不存在;相比于零售商提前期,制造商提前期对制造商的库存量牛鞭效应影响更大.同时,价格敏感性系数、价格自相关系数等因素对制造商库存量牛鞭效应也有不同程度的影响.