1. The Impact of Inventory Parameters on Supply Chain Performance 산업공학과 제조통합자동화 실험실 2001.8.14 화 발표: 김해중

2. The impact of inventory and flow planning parameters on supply chain performance:An exploratory study <Int. J. Production Economics 71 (2001) 111~118> Ram Ganeshan, Tonya Boone, School of Business, College of William and Mary, Williamsburg, USA Alan J. Stenger. Department of Business Logistics, Penn State University. USA

3. Contents Inventory parameters 설정 가설 설정 Simulation을 통한 가설 검정 MAI Lab

4. Introduction • Research in Inventory • Determining optimal inventory policies • Positioning of inventory in the supply chain • Analyzing the costs and benefits of technology and information sharing • Inventory-related advantages of product postponement Objectives of study Impact of selected inventory parameters MAI Lab

5. Inventory planning parameters i) Forecast methodology - Forecast error ii) The mode of communication between echelons - DRP(Distribution Resource Planning) - ROP(Reorder Point) iii) The planning frequency - How open the product or material requirements are re-computed MAI Lab

6. Supply chain performance parameters i) Observed service level - proportion of demand satisfied at the DCs from inventory - Overall service level: volume-weighted average of each service level ii) Supply chain cycle time - the time spent by the product as raw material, WIP, or a finished good - The time spent as inventory and the time spent in transit iii) Return on investment - Profit contribution as the proportion of the total investment MAI Lab

7. Hypothesis(1/3) • Impact of forecast error or methodology • Before : De Bodt, Van Wassenhove not supply chain, but a single site in the network First hypothesis Null: The forecast errors have no effect on cycle time and service levels Alternative: Increasing forecast errors will increase the cycle time and decrease observed service levels. MAI Lab

8. Hypothesis(2/3) • Impact of flow planning methodology • DRP procedure gives the higher level of visibility in planning product requirements • DRP plans for the exact distribution needs Second hypothesis Null: The DRP and the ROP methodology have the same effect on the observed service level in the supply chain Alternative: The DRP methodology achieves a higher level of observed service level than the ROP in the supply chain. MAI Lab

9. Hypothesis(3/3) • Impact of replanning frequency • Before : Sridharan, Berry increasing replanning frequency -> decreasing stability not supply chain, but a horizon MRP(one site) Third hypothesis Null: The replanning frequency has no effect on the cycle time or the service level Alternative: A decrease in replanning frequency will increase cycle time and decrease observed service level MAI Lab

10. Methodology MAI Lab

11. Case study and network design MAI Lab

12. Simulation Forecast error - normally distributed ~(θ,σ2) - σ2 =aAjb Aj: average period sales at DCj • Forecast demand DCj, time period t XFjt = XSjt + є ii) Output - Service level - Inventory level MAI Lab

13. Experiment result b=0.8 MAI Lab

14. Experiment result MAI Lab

15. Conclusions Forecasting errors and the re-planning frequency service, ROI Cycle time DRP service MAI Lab

16. Discussion • 분산분석의 한계(검정만 가능)을 넘어서는 평가방법? 예) 민감도 분석 MAI Lab

17. DRP(Distribution Resource Planning) • 개념 • Andre J. Martin에 의해 고안된 (MRP 개념 창안자) • 어떤 제품을 얼마만큼 언제 어디(Source Site)에서 어디(Receiving Site)로 이동시켜야 하는 지를 계획하는 것. • 목적 • 고객과 가장 가까운 곳에서 수요데이터를 얻고, 수요를 예측하여 이를 생산계획의 수립에 빠르게 반영 • 운송 계획을 통한 유통망상 재고의 획기적인 감소 • 등장배경 • 과잉재고 • 재고고갈 • 낮은 고객서비스 • 과다한 물류비용 • 빠른 기업환경의 변화 MAI Lab

18. DRP • 필요한 데이터 • 운송제품의 무게, 부피 • 운송자원의 종류, 용량 • Site 월력(Calendar) • 운송 네트워크 • 운송 비용 • MRP와의 비교 • MRP: 한 Site에서 수요와 현재고에 대한 정보를 기준으로 생산량/구매량과 시점을 결정, BOM, Routing • DRP: 여러 Site상(Distribution Network)에서 각 Site별로 수요, 재고, 생산량/구매량과 시점을 결정, Bill of Distribution MAI Lab

19. DRP 전개 예(1/3) 고객의 수요를 예측, 수급계획 수립 MAI Lab

20. DRP 전개 예 (2/3) DRP Record-서울대리점, 부산대리점 MAI Lab

21. DRP 전개 예 (3/3) DRP Record – 남한 물류센터 Back MAI Lab