1-1 value of information 問題製造商進行市場需求預測時 --- 零售商是否...

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Value of Information

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

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5.1 IntroductionValue of using any type of information

technologyPotential 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”

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Information Types

Inventory levelsOrdersProductionDelivery status

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案例www.books.com.tw

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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…

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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.

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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.

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問題方案討論假日九折 ( 降低需求變異 )寒、暑假期間提供外送服務… ( 人力運用 )

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5.2 Bullwhip EffectWhile 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.

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4-Stage Supply Chain

FIGURE 5-5: The supply chain

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Increasing Variability of Orders Up the Supply Chain

Lee, H, P. Padmanabhan and S. Wang (1997), Sloan Management Review

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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)

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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

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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 ??

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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 demand

variability implies: a significant change in safety stock and base-stock

level, which implies significant changes in order quantities leads to an increase in variability

Factors that Contribute to the Variability – Lead Time

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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…

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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 discountsRelatively small orders at other time periods

案例：第二雙一折、換季折扣…

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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 ordersleads to all kinds of distortions and

variations in demand estimates

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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： 35100日本核災大量屯積食鹽…

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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 period t 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

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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,

t tˆ L z LS

t t 1

ii t p

D

p

t 1 2

i ti t p2t

(D )S

p 1

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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

2

2

Var(Q) 2L 2L1

Var(D) p p

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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

Var(Q)Var(D)

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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

Var(Q)1.4

Var(D)

Var(Q)1.2

Var(D)

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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 decrease p

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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.

RetailerStage 1

Manufacturer Stage 2

Supplier Stage 3

Qo=D Q1 Q2

L1 L2

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Impact of Centralized Information on Bullwhip Effect

Centralize demand information within a supply chainProvide 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

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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 the total lead time between that stage and the retailer

k k 2ki ii 1 i 1

2

2 L 2( L )Var(Q )1

Var(D) p p

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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.

2k ki i

2i 1

2L 2LVar(Q )(1 )

Var(D) p p

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Multi-Stage Systems (Li=1) : Var(Qk)/Var(D)

0

5

10

15

20

25

30

0 5 10 15 20 25

Dec, k=5

Cen, k=5

Dec, k=3

Cen, k=3

k=1

Var(Q)Var(D)

P

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Managerial Insights

Variance increases up the supply chain in both centralized and decentralized cases

Variance increases:Additively with centralized caseMultiplicatively with decentralized case

Centralizing demand information can significantly reduce the bullwhip effect Although not eliminate it completely!!

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Methods for Coping with the Bullwhip1

Reducing uncertainty. Centralizing informationPOSSharing forecasts and policies

Reducing variability. Reducing variability inherent in the

customer demand process. Eliminate promotions“Everyday low pricing” (EDLP) strategy.

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問題討論第二雙皮鞋一折…名牌鞋下殺 2 折…，排隊買 40 雙…

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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.

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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

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Contractual Incentives to Get True Forecasts from Buyers

Capacity Reservation Contract Buyer pays 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

Supplier charges 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

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5.4 Information for Effective Forecasts1

Retailer forecasts Typically based on an analysis of previous sales

at the retailer. Future customer 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

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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…

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Information for Effective Forecasts2

Cooperative forecasting systemsSophisticated information systems

enable an iterative forecasting processall 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

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5.5 Information for the Coordination of Systems1

Many interconnected systemsmanufacturing, storage, transportation,

and retail systemsthe 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

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5.5 Information for the Coordination of Systems2

Systems are not coordinatedeach facility in the supply chain does what

is best for that facilitythe result is local optimization. 例如，行銷與製造的對立…

Information is required to move from local to global optimization

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Global Optimization Issues:

Who will optimize? How will the savings obtained through the

coordinated strategy be split 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

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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)

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案例我要買 new ipad…我要買這款運動褲…

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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 accurate forecasts due to a

decreased forecast horizon.Reduction in finished goods inventory

levels

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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…

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Lead-Time Reduction2

Many firms actively look for suppliers with shorter lead times

Many potential customers consider lead time a very important criterion for vendor selection.

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)

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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。

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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。

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Wish-Lists of the Different Stages1

Raw material suppliersStable volume requirements and little

variation in mixFlexible delivery timesLarge volume demands

Manufacturing High productivity through production

efficiencies and low production costsKnown future demand pattern with little

variability.

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Wish-Lists of the Different Stages2

Materials, warehousing, and outbound logistics Minimizing transportation costs through:

quantity discounts, minimizing inventory levels, quickly replenishing stock.

Retailers Short order lead times and efficient,

accurate order delivery Customers

In-stock items, enormous variety, and low prices.

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Trade-Offs: Inventory - Lot Size1

Manufacturers would like to have large lot sizes. Per unit setup costs are reduced Manufacturing expertise for a particular product

increases Processes are easier to control. 例如，可口可樂…但是可口可樂可以，服飾業者…

lead to high inventory Modern practices [Setup time reduction, Kanban and

CONWIP (constant work in process) ] Reduce inventories and improve system

responsiveness. Advanced manufacturing systems make it

possible for manufacturers to meet shorter lead times and respond more rapidly to customer needs.

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Trade-Offs: Inventory - Lot Size2

Manufacturer should have as much time as possible to react to the needs of downstream supply chain members.

Distributors/retailers can have factory status and manufacturer inventory data:they can quote lead times to customers

more accurately. develops an understanding of, and

confidence in, the manufacturers’ ability. (因預期短缺而膨脹訂單的狀況可消除 )

allows reduction in inventory in anticipation of manufacturing problems

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案例如果早知道政府會干預鹽價的穩定，就不會屯積了…

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Trade-offsInventory - Transportation Costs1

Company operates its own fleet of trucks. Fixed cost of operation + variable costCarrying full truckloads minimizes

transportation costs.Outside firm is used for shipping

quantity discountsTL shipping cheaper than LTL shipping

In many casesdemand is much less than TLItems sit for a long time before consumption

leading to higher inventory costs.

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Trade-offsInventory - Transportation Costs2

Trade-off can’t be eliminated completely. Use advanced information technology to

reduce this effect. Distribution control systems allow combining

shipments of different products from warehouses to stores

Cross-docking, Decision-support systems allow appropriate

balance between transportation and inventory costs

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腦力激盪―方案 A

Distributor

10km

90km

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腦力激盪―方案 B

Distributor

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腦力激盪―方案 A: 210+210=420 km

Distributor

10km

90km

10km

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腦力激盪―方案 B:50+230=280 km

Distributor

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Trade-offsLead Time - Transportation Costs1

Transportation costs lowest when large quantities of items are transported between stages of the supply chain. Hold items to accumulate enough to

combine shipments

Or (trade-off)Lead times can be reduced if items are

transported immediately after they are manufactured or arrive from suppliers.

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Trade-offsLead Time - Transportation Costs2

Cannot be completely eliminatedInformation can be used to reduce its

effect. Control transportation costs reducing

the need to hold items until a sufficient number accumulate.

Improved forecasting techniques and information systems reduce the other components of lead time

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Trade-OffsProduct Variety - Inventory

Higher product variety makes supply chain decisions more complexBetter for meeting customer demandTypically leads to higher inventories

Strategies:Delayed Differentiation (Chapter 6)

Ship generic products as far as possible down the supply chain

Design for logistics (Chapter 11)

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Trade-OffsCost - Customer Service

Reducing inventories, manufacturing costs, and transportation costs typically comes at the expense of customer service

Customer service could mean the ability of a retailer to meet a customer’s demand quickly

Strategies: transshipping direct shipping from warehouses to customers Charging price premiums for mass customization

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案例傢俱 3C賣場的直送策略…

低存貨成本高顧客服務水準

種類多訂購前置時間短

•雲端便利商店―存貨、前置時間、顧客服務水準…

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5.9 Decreasing Marginal Value of Information1

Obtaining and sharing information is not free. Many firms are struggling with exactly how to

use the data they collect through loyalty programs, RFID readers, and so on.

Cost of exchanging information versus the benefit of doing so. May not be necessary to exchange all of the available

information, or to exchange information continuously.

Decreasing marginal value of additional information

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In multi-stage decentralized manufacturing supply chains many of the performance benefits of detailed information sharing can be achieved if only a small amount of information is exchanged between supply chain participants.

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Exchanging more detailed information or more frequent information is costly.Understand the costs and benefits of

particular pieces of informationHow often this information is collectedHow much of this information needs to be

storedHow much of this information needs to be

sharedIn what form it needs to shared

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問題討論小型連鎖加盟體系導入 POS 的必要性…個人理財管理系統個人物品搜尋系統智慧型冰箱…

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Summary The bullwhip effect suggests that variability in

demand increases as one moves up in the supply chain.

Increase in variability causes significant operational inefficiencies

Specific techniques to “counteract” bullwhip effect Information 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-offs

1-1 value of information 問題 製造商進行市場需求預測時 --- 零售商是否...

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1-1 value of information 問題製造商進行市場需求預測時 --- 零售商是否...