1. Centralization and EOQ Prepared by A. Asef-Vaziri Based on the Book: Managing Business Process Flow

2. 2 Ardavan Asef-Vaziri Sep-2012Basic Inventory Model Central Electric (CE) serves its European customers through a distribution network that consisted of four warehouses, in Poland, Italy, France, and Germany. The network of warehouses was built on the premise that it will allow CE to be close to the customer. Contrary to expectations, establishing the distribution network led to an inventory crisis. CE is considering to consolidate the original warehouses into a single master warehouse in Austria. The following data is for the sake of analysis of this problem - not real world data. Currently, each warehouse manages its ordering independently. Demand at each outlet averages 800 units per day. Each unit of product costs $200, and CE has a holding cost of 20% per annum. The fixed cost of each order (administrative plus transportation) is $900. Assume a year is 250 days. Problem 3; Centralization vs. Decentralization

3. 3 Ardavan Asef-Vaziri Sep-2012Basic Inventory Model The holding cost will be the same in both decentralized and centralized ordering systems. The ordering cost in the centralized ordering system is twice the amount of the decentralized ordering system. Decentralized: Four warehouses in Poland, Italy, France, and Germany Centralized: One warehouse in Austria Problem 3; Centralization vs. Decentralization

4. 4 Ardavan Asef-Vaziri Sep-2012Basic Inventory Model Four outlets Each outlet demand D = 800(250) = 200,000 S= 900 C = 200 H = 0.2(200) = 40 If all warehouses merged into a single warehouse, then S= 1800 EOQ and Cycle Inventory =3000 With a cycle inventory of 1500 units for each warehouse. b) Compute EOQ and cycle inventory in the centralized ordering In this problem, in the centralized system, S = $1800. =8485 and a cycle inventory of 4242.5. a)Compute EOQ and cycle inventory in decentralized ordering The total cycle inventory across all four outlets equals 6000.

5. 5 Ardavan Asef-Vaziri Sep-2012Basic Inventory Model Comparison of the two policies Decentralized Decentralized: TC for all 4 warehouses = 4(120000)=480000 Centralized 339411 compared to 480000 about 30% improvement c) Compute the total annual holding cost + ordering cost (not including purchasing cost) for both policies

6. 6 Ardavan Asef-Vaziri Sep-2012Basic Inventory Model Optimal Policy d) Compute the ordering interval in decentralized and centralized systems. Decentralized = (3000/200000)(250) = 3.75 days Centralized = (8485/800000)(250) = 2.65 days e) If the lead time is 2 days, when do you order? (re-order point)? Decentralized 2(200000)/(250) = 1600 units Centralized = 6400 units

7. 7 Ardavan Asef-Vaziri Sep-2012Basic Inventory Model Inventory Turns f) Compute inventory turns Inventory Turns = Demand /Average inventory Demand Average inventory Inventory Turns 2000001500 200000/1500 = 133.33 8000004242.5800000/4242.5 = 188.57 g) Compute the average flow time RT = I 200000T= 1500  T = 1500/200000 year or 1.875 days 800000T= 4242.5  T = 1500/200000 year or 1.326 days

8. 8 Ardavan Asef-Vaziri Sep-2012Basic Inventory Model Why We are interested in reducing inventory. Inventory adversely affects all competing edges (P/Q/V/T)  Has cost –Physical carrying costs –Financial costs  Has risk of obsolescence –Due to market changes –Due to technology changes  Leads to poor quality –Feedback loop is long  Hides problems –Unreliable suppliers, machine breakdowns, long changeover times, too much scrap.  Causes long flow time

9. 9 Ardavan Asef-Vaziri Sep-2012Basic Inventory Model How to Reduce EOQ Two ways to reduce average inventory -Reduce S -Centralize S does not increase in proportion of R EOQ increases as the square route of demand.

10. 10 Ardavan Asef-Vaziri Sep-2012Basic Inventory Model Why not Always Centralized If centralization reduces inventory, why doesn’t everybody do it? – Higher shipping cost – Longer response time – Less understanding of customer needs – Less understanding of cultural, linguistics, and regulatory barriers These disadvantages my reduce the demand.