《供应链管理教学课件》第4章信息的价值-供应链管理.ppt

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1、第四章第四章 信息的价值信息的价值The Value of Information供供供供 应应应应 链链链链 管管管管 理理理理Supply Chain ManagementSupply Chain Management2本章内容本章内容牛鞭效应牛鞭效应有效预测有效预测协调系统的信息协调系统的信息找出所需产品找出所需产品缩短提前期缩短提前期信息和供应链的权衡信息和供应链的权衡3简介（简介（1）我们生活在信息的时代中“In modern supply chains,information replaces inventory”（信息取代了库存）Why is this true?Why is t

2、his false?Information is always better than no information信息如何影响供应链的设计与运作通过有效地利用可取得的信息，我们可以比以前更有效益及更有效率地设计与运作供应链4简介（简介（2）丰富的信息将Helps reduce variability（协助减少供应链的变动性）Helps improve forecasts（协助供货商作出更好的预测）Enables coordination of systems and strategies（使制造和分销系统与策略能够协调）Improves customer service（通过提供定位所需商品

3、的工具，使零售商为顾客提供更好的服务）Facilitates lead time reductions（能减少提前期）Enables firms to react more quickly to changing market conditions（使零售商能更快地反应并适应供应方面的问题）5牛鞭效应（牛鞭效应（The Bullwhip Effect）在供应链中愈往上游走，订单数量变动性愈增大的现象就是牛鞭效应Order variability is amplified up the supply chain;upstream echelons face higher variabilityW

4、hat you see is not what they face6牛鞭效应：牛鞭效应：Example（1）一个简单的四级供应链一个零售商一个批发商一个分销商一个工厂7牛鞭效应：牛鞭效应：Example（2）零售商所下的订单的变动会比顾客需求高，批发商被迫持有较零售商多的安全库存，或必须要能较零售商保持更高的能力以维持同样的服务水平8供应链中导致变动性增加的主要因素供应链中导致变动性增加的主要因素需求预测（Demand Forecasting）Order-up-to points are modified as forecasts change orders increase more tha

5、n forecasts提前期（Lead Time）Long lead times magnify this effect批量订购（Batching）Volume and transportation discounts价格波动（Price Fluctuation）被夸大的订单（Inflated Orders）IBM Aptiva orders increased by 2-3 times when retailers thought that IBM would be out of stock over ChristmasMotorola cell phones9The Bullwhip Ef

6、fect:Managerial InsightsExists,in part,due to the retailers need to estimate the mean and variance of demandThe increase in variability is an increasing function of the lead timeThe more complicated the demand models and the forecasting techniques,the greater the increaseCentralized demand informati

7、on can significantly reduce the bullwhip effect,but will not eliminate itQuantifying the BullwhipConsider a two-stage supply chain:Retailer who observes customer demandRetailer places an order to a manufacturer.Retailer faces a fixed lead timeorder placed at the end of period t Order received at the

8、 start of period t+L.Retailer follows a simple periodic review policy retailer reviews inventory every periodplaces an order to bring its inventory level up to a target level.the review period is one10Quantifying the BullwhipBase-Stock Level=L x AVG+z x STD x LOrder up-to point=If the retailer uses

9、a moving average technique,with p observations to forecast demand 11Quantifying the Increase in VariabilityVar(D),variance of the customer demand seen by the retailer Var(Q),variance of the orders placed by that retailer to the manufacturerWhen p is large and L is small,the bullwhip effect is neglig

10、ible.Effect is magnified as we increase the lead time and decrease p.12Lower Bound on the Increase in Variability Given as a Function of pFIGURE 5-7:A lower bound on the increase in variability given as a function of p13Impact of Variability ExampleAssume p=5,L=1Assume p=10,L=1Increasing p the numbe

11、r of observations used in the moving average forecast reduces the variability of the retailer order to the manufacturer1415牛鞭效应下信息集中的影响（牛鞭效应下信息集中的影响（1）最常被提出降低牛鞭效应的建议就是在供应链中集中需求的信息根据实际的顾客需求，在供应链每一个级提供完整的信息若需求信息是集中化的，那么在供应链中的每一个级都可使用正确的顾客需求数据，并以此产生正确的预测，而不是依赖前几个级传来的订单，而其可能会比真实的顾客需求变动的更多16牛鞭效应下信息集中的影响（

12、牛鞭效应下信息集中的影响（2）为了决定牛鞭效应里集中化需求信息的影响，我们将区分两种不同型态的供应链：集中式的需求信息分布式的需求信息17需求信息集中式的供应链需求信息集中式的供应链在集中式供应链中，供应链中的每一个级收到零售商所预测的平均需求，并根据这个平均需求确定库存上限水平的库存政策在此情形下，将需求的信息、预测的技术及库存政策集中化处理供应链中某一级所下订单的方差是该级与零售商之间全部提前期的递增函数Variability with Centralized InformationVar(D),variance of the customer demand seen by the ret

13、ailer Var(Qk),variance of the orders placed by the kth stage to itsLi,lead time between stage i and stage i+1Variance of the orders placed by a given stage of a supply chain is an increasing function of the total lead time between that stage and the retailer 1819分布式的需求信息分布式的需求信息分布式供应链中，零售商不提供他所预测的平均

14、需求给供应链中的其它主体批发商必须要根据从零售商那里收到的订单，计算平均需求在分布式供应链中，只有零售商知道顾客的需求，所以会比集中式供应链具更多的变动而在集中式供应链中，供应链中的任何级都可得到顾客需求信息因此，可以推断集中式的需求信息可以降低牛鞭效应供应链中某一级所下订单的方差是以乘积的方式在增加Variability with Decentralized InformationRetailer does not make its forecast information available to the remainder of the supply chainOther stages

15、have to use the order informationVariance of the orders:becomes larger up the supply chain increases multiplicatively at each stage of the supply chain.20Managerial InsightsVariance increases up the supply chain in both centralized and decentralized casesVariance increases:Additively with centralize

16、d caseMultiplicatively with decentralized caseCentralizing demand information can significantly reduce the bullwhip effect Although not eliminate it completely!21Increase in Variability for Centralized and Decentralized Systems FIGURE 5-8:Increase in variability for centralized and decentralized sys

17、tems2223克服牛鞭效应的方法克服牛鞭效应的方法降低不确定性（Reduce uncertainty）POSSharing informationSharing forecasts and policies降低变动性（Reduce variability）Eliminate promotionsEvery-day low pricing(EDLP)减少提前期（Reduce lead times）EDICross docking战略伙伴关系（Strategic partnerships）Vendor managed inventory(VMI)Data sharing24Example:Qui

18、ck Response at Benetton（1）Benetton,the Italian sportswear manufacturer,was founded in 1964.In 1975 Benetton had 200 stores across Italy.Ten years later,the company expanded to the US,Japan and Eastern Europe.Sales in 1991 reached 2 trillion.Many attribute Benettons success to successful use of commu

19、nication and information technologies.25Example:Quick Response at Benetton（2）Benetton uses an effective strategy,referred to as Quick Response,in which manufacturing,warehousing,sales and retailers are linked together.In this strategy a Benetton retailer reorders a product through a direct link with

20、 Benettons mainframe computer in Italy.Using this strategy,Benetton is capable of shipping a new order in only four weeks,several week earlier than most of its competitors.26How Does Benetton Cope with the Bullwhip Effect?Integrated Information SystemsGlobal EDI network that links agents with produc

21、tion and inventory informationEDI order transmission to headquartersEDI linkage with air carriersData linked to manufacturingCoordinated PlanningFrequent review allows fast reactionIntegrated distribution strategyInformation Sharing And Incentives Centralizing information will reduce variabilityUpst

22、ream stages would benefit moreUnfortunately,information sharing is a problem in many industriesInflated forecasts are a realityForecast information is inaccurate and distortedForecasts inflated such that suppliers build capacitySuppliers may ignore the forecasts totally27Contractual Incentives to Ge

23、t True Forecasts from BuyersCapacity Reservation ContractBuyer pays to reserve a certain level of capacity at the supplierA menu of prices for different capacity reservations provided by supplierBuyer signals true forecast by reserving a specific capacity levelAdvance Purchase ContractSupplier charg

24、es special price before building capacityWhen demand is realized,price charged is differentBuyers commitment to paying the special price reveals the buyers true forecast2829有效的预测（有效的预测（1）信息导致更有效的预测愈多未来需求的因素能够被加以考虑，预测的正确性就越高Pricing,Promotion,New ProductsDifferent parties have this informationRetailer

25、s may set pricing or promotion without telling distributorDistributor/Manufacturer might have new product or availability information30有效的预测（有效的预测（2）许多供应链正向联合预测系统（Collaborative Forecasting Systems）迈进在这些系统中，复杂的信息系统提供了一个反复的预测程序，使供应链中的参与者透过合作能够达到对预测有一致的共识这暗示了供应链所有的参与者分享并使用相同的预测工具，从而导致牛鞭效应的降低31系统协调的信息（系

26、统协调的信息（1）在任何的供应链当中有许多系统，包含了不同的制造、仓储、运输以及零售系统所有这些系统是连结在一起的。进一步来看，这些来自供应链当中一个系统的产出是下一个系统的投入因此，试着为任何一个阶段找寻最佳效益背反的答案是不够的。我们需要考虑整个系统并协调相关决策32系统协调的信息（系统协调的信息（2）Information is required to move from local to global optimisation当系统不协调时也就是每一个供应链当中的成员追求自己最大的利益其结果是局部最佳化供应链的每一个成员只寻求自己运作的最佳化，而不去注意本身的政策对供应链其它成员的影响

27、相对于上述方式的是全局最优化全局最优化意味去确认什么才是对整个系统最好的做法33系统协调的信息（系统协调的信息（3）有两个议题需要被注意：Who will optimise：谁来做最佳化？How will savings be split：如何使透过协调的策略而节省下的成本能在不同供应链的成员之间彼此分享？Information is needed:Production status and costsTransportation availability and costsInventory informationCapacity informationDemand information3

28、4找到需要的产品找到需要的产品How can demand be met if products are not in inventory?Locating products at other storesWhat about at other dealers?有很多种方式可以满足顾客的需求。对一个库存式生产系统（Made to Stock）而言，我们希望从零售的库存来满足顾客需求但能够找出且配送产品，有时与拥有库存一样有效但如果商品是在零售商的竞争者手中，这些竞争者是否愿意为零售商调拨商品则不是很明朗35提前期的缩短（提前期的缩短（1）缩短提前期的重要性是不能被忽视的。它通常会导致：Cust

29、omer orders are filled quickly：快速满足无法以库存来满足顾客订单的能力Bullwhip effect is reduced：减少牛鞭效应Forecasts are more accurate：因为预测期的缩减，带来更正确的预测结果Inventory levels are reduced：减少产成品的库存水平36提前期的缩短（提前期的缩短（2）为了这些理由，许多厂商正积极地寻求具备更短提前期的供货商，而且许多潜在的顾客认为提前期对于供货商的选择是一个非常重要的标准二十世纪晚期许多制造革命导致提前期的减少，这些设计能够存在是因为整个供应链的状态信息可被获取例如EDI系

30、统藉由减少提前期的成份如订单流程、纸质作业、库存分拣等来缩短提前期用POS系统自零售商传送数据到供货商能够协助减少提前期，是因为供货商能够透过POS系统的数据来预测将要到来的订单37信息和供应链的效益背反信息和供应链的效益背反供应链不同级经理人间均有冲突的目标，而对供应链中不同级的整合或协作也造成了冲突甚至在一个级中，降低库存水平或运输成本的效益背反，或是增加产品多样性的效益背反也常常出现通过仔细利用可获得的信息，供应链可以更趋近于全局最优化，并依据不同冲突目标和不同效益背反，降低整个系统的成本38供应链中互相冲突的目标供应链中互相冲突的目标原料供货商制造管理物料、仓库、外向物流管理零售商顾客

31、稳定的需求、所需物料组合几乎不变、可灵活变动的交货期、大量的需求高生产率、低生产成本、需求模式提前已知且没有什么变动利用数量折扣最小化运输成本、最小化库存和快速补充库存商品有存货、种类多、价格低短的订货提前期、有效率的正确交货39目标冲突的供应链设计目标冲突的供应链设计在过去，为了达成某些目标，另外一些目标必须要被牺牲。供应链被视为是一连串要决定的效益背反现在可获得大量的信息来设计供应链，使其能接近达到这些表面上看来是冲突的目标一些在几年前被认为是在供应链中存在的效益背反，现在已不再互相抵触40供应链中存在的效益背反（供应链中存在的效益背反（1）这些效益背反，及这些效益背反如何通过先进技术及创

32、新的网络设计，使得他们在现代供应链中不会再有效益背反或至少被降低批量大小 库存的效益背反（Lot Size Inventory）Advanced manufacturing systemsPOS data for advance warnings库存 运输成本效益背反（Inventory Transportation）Lead time reduction for batchingInformation systems for combining shipmentsCross dockingAdvanced DSS41供应链中存在的效益背反（供应链中存在的效益背反（2）提前期 运输成本（Lea

33、d Time Transportation）Lower transportation costsImproved forecastingLower order lead times产品多样性 库存效益背反（Product Variety Inventory）Delayed differentiation成本 顾客服务的效益背反（Cost Customer Service）Transhipment信息的边际价值递减信息的边际价值递减信息的获取与共享不是免费的需要比较信息交换的成本与信息交换所带来的存在信息边际价值递减，企业交换了信息的主要部分，那么企业交换信息其他附加部分就只有很少的利益特定的供

34、应链中，如果低端一个星期下一次订单，那么能从每星期24次需求信息共享中获得大部分的收益，每星期超过4次的信息共享所能获得的额外收益是极少的分散型制造供应链中，如果供应链参与者仅仅交换一小部分的信息（如什么时候能完工），那么他们将获得许多共享具体信息的收益交换更多详细的信息或更频繁的交换信息成本会更大42SummaryThe bullwhip effect suggests that variability in demand increases as one moves up in the supply chain.Increase in variability causes signific

35、ant operational inefficienciesSpecific techniques to“counteract”bullwhip effectInformation sharing,i.e.,centralized demand information.Incentives to share credible forecasts Alignments of expectations associated with the use of information.Interaction of various supply chain stages.A series of trade-offs both within and between the different stages.Information is the key enabler of integrating the different supply chain stages Information can be used to reduce the necessity of many of these trade-offs43