製造商進行市場需求預測時 --- 零售商是否有特殊的促銷計畫 ?... 零售商進行市場需求預測時 --- 製造商是否有特殊的新產品開發計畫 ?... 製造商接到比平常更大量的訂單 --- 為一個月前的市場需求變動！！ … 一個瓶子五萬元，全

1. 問題 • 製造商進行市場需求預測時---零售商是否有特殊的促銷計畫?... • 零售商進行市場需求預測時---製造商是否有特殊的新產品開發計畫?... • 製造商接到比平常更大量的訂單---為一個月前的市場需求變動！！… • 一個瓶子五萬元，全省有20個銷售點…庫存成本 vs. 缺貨風險

2. 5.1 Introduction • Value of using any type of information technology • Potential availability of more and more information throughout the supply chain • Implications this availability on effective design and management of the integrated supply chain • “In modern supply chains, information replaces inventory”

3. Information Types • Inventory levels • Orders • Production • Delivery status

4. 案例 • www.books.com.tw

5. 問題 • Mint該準備多少意大利麵相關食材? • 平均需求 vs • 平時 • 假日 • 期中考、期末考 • 校慶、畢業典禮 • 寒暑假平時 • 寒暑假假日…

6. Value of Information1 • Helps reduce variability in the supply chain. • Helps suppliers make better forecasts, accounting for promotions and market changes. • Enables the coordination of manufacturing and distribution systems and strategies.

7. Value of Information2 • Enables retailers to better serve their customers by offering tools for locating desired items. • 我要喝南瓜湯… • Enables retailers to react and adapt to supply problems more rapidly. • 鏡頭罩缺貨一週內到貨 • Enables lead time reductions.

8. 問題方案討論 • 假日九折 • 寒、暑假期間提供外送服務…(人力運用)

9. 5.2 Bullwhip Effect • While customer demand for specific products does not vary much • Inventory and back-order levels fluctuate considerably across their supply chain • The increase in variability as we travel up in the supply chain is referred to as the bullwhip effect.

10. 4-Stage Supply Chain FIGURE 5-5: The supply chain

11. Increasing Variability of Orders Up the Supply Chain Lee, H, P. Padmanabhan and S. Wang (1997), Sloan Management Review

12. Factors that Contribute to the Variability - Demand Forecasting1 • Periodic review policy • Characterized by a single parameter, the base-stock level. • Base-stock level = Average demand during lead time and review period+ a multiple of the standard deviation of demand during lead time and review period(safety stock)

13. Factors that Contribute to the Variability - Demand Forecasting2 • Estimation of average demand and demand variability done using standard forecast smoothing techniques. • Estimates get modified as more data becomes available • Safety stock and base-stock level depends on these estimates • Order quantities are changed accordingly increasing variability

14. 案例 • 原物料價格上漲… • 美金下跌… • 人民幣上漲… • 日幣下跌(20%)… • 訂購量??

15. Factors that Contribute to the Variability – Lead Time • Increase in variability magnified with increasing lead time. • Safety stock and base-stock levels have a lead time component in their estimations. • With longer lead times: • a small change in the estimate of demandvariability implies: • a significant change in safety stock and base-stock level, which implies • significant changes in order quantities • leads to an increase in variability

16. Factors that Contribute to the Variability – Batch Ordering • Retailer uses batch ordering, as with a (Q,R) or a (s, S) (or min-max) policy • Wholesaler observes a large order, followed by several periods of no orders, followed by another large order, and so on. • Wholesaler sees a distorted and highly variable pattern of orders. • Such pattern is also a result of: • Transportation discounts with large orders • Periodic sales quotas/incentives • 例如，百貨公司週年慶…

17. Factors that Contribute to the Variability – Price Fluctuations • Retailers often attempt to stock up when prices are lower. • Accentuated by promotions and discounts at certain times or for certain quantities. • Such Forward Buying (預先購買) results in: • Large order during the discounts • Relatively small orders at other time periods • 案例：第二雙一折…

18. Factors that Contribute to the Variability – Inflated Orders • Inflated orders during shortage periods • Common when retailers and distributors suspect that a product will be in short supply and therefore anticipate receiving supply proportional to the amount ordered. • After period of shortage, retailer goes back to its standard orders • leads to all kinds of distortions and variations in demand estimates

19. 案例 • IBM Aptiva orders increased by 2-3 times when retailers thought that IBM would be out of stock over Christmas. • H7N9 口罩工廠加班趕工… • N95口罩：35100 • 日本核災大量屯積食鹽…

20. Quantifying the Bullwhip • Consider a two-stage supply chain: • Retailer who observes customer demand • Retailer places an order to a manufacturer. • Retailer faces a fixed lead time(L) • Order placed at the end of periodt • Order received at the start of period t+L. • Retailer follows a simple periodic review policy • retailer reviews inventory every period • places an order to bring its inventory level up to a target level. • the review period is one

21. Quantifying the Bullwhip • Base-Stock Level = (L+1) x AVG + z x STD x (L+1)1/2 • Order up-to point = • If the retailer uses a moving average technique,

22. Quantifying the Increase in Variability • Var(D),variance of the customer demand seen by the retailer • Var(Q),variance of the orders placed by that retailer to the manufacturer

23. Var(Q) Var(D) Lower Bound on the Increase in Variability Given as a Function of p FIGURE 5-7: A lower bound on the increase in variability given as a f unction of p

24. Impact of Variability Example • Assume p = 5, L=1 • Assume p = 10, L=1 • Increasing the number of observations used in the moving average forecast reduces the variability of the retailer order to the manufacturer

25. Conclusions • When p is large and L is small, the bullwhip effect due to forecasting error is negligible • The bullwhip effect is magnified as we increase the lead time and decreasep

26. Qo=D Q1 Q2 Retailer Stage 1 Manufacturer Stage 2 Supplier Stage 3 L1 L2 Bullwhip effect ―Multi-Stage Supply Chains1 • Consider a multi-stage supply chain: • Stage i places order Qi to stage i+1. • Li is lead time between stage i and i+1.

27. Impact of Centralized Information on Bullwhip Effect • Centralize demand information within a supply chain • Provide each stage of supply chain with complete information on the actual customer demand • Creates more accurate forecasts rather than orders received from the previous stage

28. Variability with Centralized Information • Var(D), variance of the customer demand seen by the retailer • Var(Qk), variance of the orders placed by the kth stage to its • Li, lead time between stage i and stage i + 1 • Variance of the orders placed by a given stage of a supply chain is an increasing function of thetotal lead time between that stage and the retailer

29. Variability with Decentralized Information • Retailer does not make its forecast information available to the remainder of the supply chain • Other stages have to use the order information • Variance of the orders: • becomes larger up the supply chain • increases multiplicatively at each stage of the supply chain.

30. Var(Q) Var(D) Dec, k=5 Cen, k=5 Dec, k=3 Cen, k=3 k=1 Multi-Stage Systems (Li=1) : Var(Qk)/Var(D) P

31. Managerial Insights • Variance increases up the supply chain in both centralized and decentralized cases • Variance increases: • Additively withcentralized case • Multiplicatively with decentralized case • Centralizing demand information can significantly reduce the bullwhip effect • Although not eliminate it completely!!

32. Methods for Coping with the Bullwhip1 • Reducinguncertainty. • Centralizing information • POS • Sharing forecasts and policies • Reducing variability. • Reducing variability inherent in the customer demand process. • Eliminate promotions • “Everyday low pricing” (EDLP) strategy.

33. 問題討論 • 第二雙皮鞋一折… • 名牌鞋下殺2折…，排隊買40雙…

34. Methods for Coping with the Bullwhip2 • Lead-time reduction • Information lead times― EDI • Order lead times― Cross docking • Strategic partnerships • Changing the way information is shared and inventory is managed • Vendor managed inventory (VMI) • Manufacturer manages the inventory of its product at the retailer outlet • VMI the manufacturer does not rely on the orders placed by a retailer, thus avoiding the bullwhip effect entirely.

35. 5.3 Information Sharing And Incentives • Centralizing information will reduce variability • Upstream stages would benefit more • Unfortunately, information sharing is a problem in many industries • Inflated forecasts are a reality • Forecast information is inaccurate and distorted • Forecasts inflated such that suppliers build capacity then • Suppliers may ignore the forecasts totally

36. Contractual Incentives to Get True Forecasts from Buyers • Capacity Reservation Contract • Buyerpays to reserve a certain level of capacity at the supplier • A menu of prices for different capacity reservations provided by supplier • Buyer signals true forecast by reserving a specific capacity level • Advance Purchase Contract • Suppliercharges special price before building capacity • When demand is realized, price charged is different • Buyer’s commitment to paying the special price reveals the buyer’s true forecast

37. 5.4 Information for Effective Forecasts1 • Retailer forecasts • Typically based on an analysis of previous sales at the retailer. • Futurecustomer demand influenced by pricing, promotions, and release of new products. • Including such information will make forecasts more accurate. • Distributor and manufacturer forecasts • Influenced by factors under retailer control. • Promotions or pricing. • 例如，頂好超市：台碑每箱85折… • Retailer may introduce new products into the stores • Closer to actual sales – may have more information

38. 問題 • Min＊該準備多少意大利麵相關食材? • 平時 • 假日 • 校慶、畢業典禮 • 寒暑假平時 • 寒暑假假日… • 新品上市… • 隔壁開了一家100元熱炒…

39. Information for Effective Forecasts2 • Cooperative forecasting systems • Sophisticated information systemsenable an iterative forecasting process • all participants in the supply chain collaborate to arrive at an agreed-upon forecast • 供應鏈所有的參與者分享資訊並使用相同的預測工具可導致長鞭效應的降低

40. 5.5 Information for the Coordination of Systems1 • Many interconnected systems • manufacturing, storage, transportation, and retail systems • the outputs from one system within the supply chain are the inputs to the next system • trying to find the best set of trade-offs for any one stage isn’t sufficient. • need to consider the entire system and coordinate decisions

41. 5.5 Information for the Coordination of Systems2 • Systems are not coordinated • each facility in the supply chain does what is best for that facility • the result is local optimization. • 例如，行銷與製造的對立… • Information is required to move from local to global optimization

42. Global Optimization • Issues: • Who will optimize? • How will the savings obtained through the coordinated strategy besplit between the different supply chain facilities? • Methods to address issues: • Supply contracts • Strategic partnerships • Information is needed : • Production status and costs • Transportation availability and costs • Inventory information • Capacity information • Demand information

43. 5.6 Locating Desired Products • Meet customer demand from available retailer inventory • What if the item is not in stock at the retailer? • Being able to locate and deliver goods is sometimes as effective as having them in stock • If the item is available at the competitor, then this is a problem • 案例，百貨公司專櫃的刮鬍液缺貨… • Other Methods • Inventory pooling (Chapter 7) • Distributor Integration (Chapter 8)

44. 案例 • 我要買new ipad… • 我要買這款運動褲…

45. 5.7 Lead-Time Reduction1 • Numerous benefits: • The ability to quickly fill customer orders that can’t be filled from stock. • Reduction in the bullwhip effect. • More accurateforecasts due to a decreased forecast horizon. • Reduction in finished goods inventory levels

46. 問題 • 關鍵零組件海外採購 • 運送前置時間長 • 訂購批量限制… • 中衛體系的優、缺點…

47. Lead-Time Reduction2 • Many firms actively look for suppliers with shorter lead times • Many potential customers consider lead time a very important criterion for vendorselection. • Much of the manufacturing revolution of the past 20 years led to reduced lead times • Other methods: • Distribution network designs (Chapter 6) • Effective information systems (e.g., EDI) • Strategic partnering (Chapter 8) (Sharing point-of-sale (POS) data with supplier)

48. 5.8 Information and Supply Chain Trade-Offs1 • 供應鏈不同階層經理人間均有衝突的目標，而對供應鏈中不同階層的整合或協作也造成了衝突。甚至在一個階層中，降低存貨水準或運輸成本的互抵效果，或是增加產品多樣性的互抵效果也常常出現。 • 藉著小心地使用可獲得的資訊，供應鏈可以更趨近於全面最佳化，並依據不同衝突目標和不同互抵效果，降低系統面的成本。

49. Information and Supply Chain Trade-Offs2 • 在過去，為了達成某些目標，另外一些目標必須要被犧牲。供應鏈被視為是一連串要決定的互抵效果。 • 大量的資訊現在已可取得，這使供應鏈能夠被設計來折衝這些彼此衝突的目標。一些在幾年前被認為是在供應鏈中存在的互抵效果，現在已不再互相抵觸。

50. Wish-Lists of the Different Stages1 • Raw material suppliers • Stable volume requirements and little variation in mix • Flexibledelivery times • Large volumedemands • Manufacturing • High productivity through production efficiencies and low production costs • Known future demand pattern with little variability.