Operations Management Unit 10: Managing Inventories (1) 授課教師： 國立臺灣大學工商管理學系 黃崇興 教授 本課程指定教材為 Operations Management: Processes and Supply Chains, 10th ed., Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Pearson Education, ©2013 本講義僅引用部分內容，請讀者自行準備。 1 【本著作除另有註明外，採取創用 CC 「姓名標示 －非商業性－相同方式分享」台灣 3.0 版授權釋出】創用 CC 「姓名標示 －非商業性－相同方式分享」台灣 3.0 版

Inventory Management 2 p.328, 329 Inventory Management Inventory

Inventory and Supply Chains 3 p.329 Figure 9.1

Pressures for small inventories 4 p.329, 330 Inventory holding cost Cost of capital Storage and handling costs Taxes, insurance, and shrinkage  Shrinkage takes three forms Pilferage Obsolescence Deterioration

Pressures for large inventories 5 p.330, 331 Customer service Ordering cost Setup cost Labor and equipment utilization Transportation cost Payments to suppliers

Types of Inventory 6 p.331, Figure 9.2, 332 Three aggregate categories  Raw materials  Work-in-process  Finished goods Classified by how it is created  Cycle inventory  Safety stock inventory  Anticipation inventory  Pipeline inventory

Cycle Inventory 7 p.331 Lot sizing principles  The lot size, Q, varies directly with the elapsed time (or cycle) between orders Average cycle inventory = = Q Q2Q2

Pipeline inventory 8 p.332 Average demand during lead time = D L Average demand per period = d Number of periods in the item’s lead time = L Pipeline inventory = D L = dL

Inventory Reduction Tactics 9 p.333, 334 Cycle inventory Safety stock inventory Anticipation inventory Pipeline inventory

ABC Analysis 10 p.334, Figure 9.4 ABC Analysis Stock-keeping units (SKU) Identify the classes so management can control inventory levels  Pareto chart

Economic Order Quantity 11 p.335 EOQ Five assumptions Don’t use the EOQ Modify the EOQ Use the EOQ

Calculating EOQ (cont.) 12 p.336 Figure 9.5

Calculating EOQ (cont.) 13 p. 336 Annual ordering cost Annual ordering cost =(Number of orders/Year)  (Ordering or setup costs) Total annual cycle-inventory cost Total costs =Annual holding cost + Annual ordering or setup cost Annual holding cost Annual holding cost =(Average cycle inventory)  (Unit holding cost)

Calculating EOQ (cont.) p.336 Figure 9.6

Calculating EOQ (cont.) 15 where C = total annual cycle-inventory cost Q = lot size H = holding cost per unit per year D = annual demand S = ordering or setup costs per lot C = ( H ) + ( S ) Q2Q2 DQDQ Total annual cycle-inventory cost p.336

EXAMPLE 9.2 The Cost of a Lot-Sizing Policy 16 p.337

Calculating EOQ 17 p.337, 338 EOQ = 2 DS H Time between orders (TBO) TBO EOQ = (12 months/year) EOQ D The EOQ formula

EXAMPLE 9.3 Finding the EOQ, Total Cost, TBO 18 p.338

Managerial Insights 19 p.339 Table 9.1

Inventory Control Systems 20 p.339,340 Two important questions Nature of demand  Independent demand  Dependent demand Discuss two inventory control systems  Continuous review system (Q)  Periodic review system (P)

Continuous review system (Q) 21 Inventory position =On-hand inventory + Scheduled receipts – Backorders IP = OH + SR – BO p.339,340

Selecting the Reorder Point When Demand and Lead Time Are Constant 22 p.340 Figure 9.9

EXAMPLE 9.4 Placing a New Order When Demand and Lead Time Are Constant 23 p.341

版權聲明 24 頁碼作品版權圖示來源 / 作者 2 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.328, 329 依據著作權法第 46 、 52 、 65 條合理使 用。瀏覽日期： 2013/05/08 。 4 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.329, 330 依據著作權法第 46 、 52 、 65 條合理使 用。瀏覽日期： 2013/05/08 。 5 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.330, 331 依據著作權法第 46 、 52 、 65 條合理使 用。瀏覽日期： 2013/05/08 。 6 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.331, 332 依據著作權法第 46 、 52 、 65 條合理使 用。瀏覽日期： 2013/05/08 。 7 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.331 依據著作權法第 46 、 52 、 65 條合理使用。 瀏覽日期： 2013/05/08 。

版權聲明 25 頁碼作品版權圖示來源 / 作者 8 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.332 依據著作權法第 46 、 52 、 65 條合理使用。 瀏覽日期： 2013/05/08 。 9 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.333, 334 依據著作權法第 46 、 52 、 65 條合理使 用。瀏覽日期： 2013/05/08 。 10 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.334 依據著作權法第 46 、 52 、 65 條合理使用。 瀏覽日期： 2013/05/08 。 11 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.335 依據著作權法第 46 、 52 、 65 條合理使用。 瀏覽日期： 2013/05/08 。 13 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.336 依據著作權法第 46 、 52 、 65 條合理使用。 瀏覽日期： 2013/05/08 。

版權聲明 26 頁碼作品版權圖示來源 / 作者 15 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.336 依據著作權法第 46 、 52 、 65 條合理使用。 瀏覽日期： 2013/05/08 。 17 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.337, 338 依據著作權法第 46 、 52 、 65 條合理使 用。瀏覽日期： 2013/05/08 。 20 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.339, 340 依據著作權法第 46 、 52 、 65 條合理使 用。瀏覽日期： 2013/05/08 。 21 Pearson Education / Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., Pearson Education,2012. p.340 依據著作權法第 46 、 52 、 65 條合理使用。 瀏覽日期： 2013/05/08 。 2-23 Pixabay/ Unknown 本作品屬公共領域之著作。瀏覽日期： 2013/05/08 。

版權聲明 27 頁碼作品版權圖示來源 / 作者 2-23 Inventory Management... EXAMPLE 9.4 Placing a New Order When Demand and Lead Time Are Constant( 各頁 標題 ) Pearson Education / Lee J., Larry P. Ritzman, and Manoj K Malhotra, Operations Management: Processes and Supply Chains, 10th ed., P 本作品以著作權法第 46 、 52 、 65 條合理使用。瀏覽日期： 2013/05/08 。