【正文】 ion, Inc. Publishing as Prentice Hall 1647 222( ) ( )w h e r e : ave r age d ail y d e m an d ave r age le ad t im e22 2( ) ( ) st an d ar d d e viat ion of d e m an d d u r in g le ad t im e2Z ( ) ( )R d L Z L dLddLLdLdLLd??????? ? ??????2 2 saf e t y st oc kd ?When both demand and lead time are variable: Reorder Point Variable Demand and Lead Time Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall 1648 30 y d p e r d ay 5 y d p e r d ay 10 d ay s3 d ay s f or 95% se r vic e le ve l222( ) ( ) ( 30) ( 10) ( ) ( 5) ( 5) ( 10) ( 3) ( 3) ( 3 0) ( 30) 300 y d sddLLZR d L Z L dLd?????????? ? ?? ? ????Carpet Discount Store: Reorder Point Variable Demand and Lead Time Example Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall 1649 Order Quantity for a Periodic Inventory System ? A periodic, or fixedtime period inventory system is one in which time between orders is constant and the order size varies. ? Vendors make periodic visits, and stock of inventory is counted. ? An order is placed, if necessary, to bring inventory level back up to some desired level. ? Inventory not monitored between visits. ? At times, inventory can be exhausted prior to the visit, resulting in a stockout. ? Larger safety stocks are generally required for the periodic inventory system. Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall 1650 For normally distributed variable daily demand: ()w h e r e : ave r age d e m an d r at e t h e f ix e d t im e b e t w e e n or d e r s le ad t im e st an d ar d d e vi at io n of d e m an d saf e t y st oc k in ve n t or y in st oc kQ d t L Z t L Ib d bdtbLdZ t LdbI???? ? ? ? ????????Order Quantity for Variable Demand Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall 1651 6 b ot t l e s p e r d ay b ot t l e s 60 d ay s 5 d ay s 8 b ot t l e s f or 95% se r vi c e l e ve l() ( 6) ( 60 5) ( ) ( ) 60 5 8 398 b ot t l e sddtbLIZQ d t L Z t L Ib d b????????? ? ? ? ?? ? ? ? ??Corner Drug Store with periodic inventory system. Order size to maintain 95% service level: Order Quantity for Variable Demand Example Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall 1652 ? For data below determine: ? Optimal order quantity and total minimum inventory cost. ? Assume shortage cost of $600 per unit per year, pute optimal order quantity and minimum inventory cost. ? Step 1 (part a): Determine the Optimal Order Quantity. Example Problem Solution Electronic Village Store (1 of 3) 1,2 00 p e r son al c om p u t e r s $170$4502 2 ( 450 ) ( 1 , 200 )79. 7 p e r son al c om p u t e r s170DCcCoCDoQCc???? ? ?Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall 1653 Step 2 (part b): Compute the EOQ with Shortages. 1 , 20229. 7T ot al c ost 170 4502 2 79. 7 $13,54 Q DCCco Q???????????? ??? ? ? ??Example Problem Solution Electronic Village Store (2 of 3) $6002 2 ( 450 ) ( 1200 ) 600 170170 600 p e r son al c om p u t e r sCsC D C Co s cQCCcs???????????????? ????Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall 1654 Example Problem Solution Electronic Village Store (3 of 3) 170 pe r son al c om p u t e r s170 60022()T ot al c ost 2222( 600 ) ( ) ( )1 , 200170 4502 ( ) 2 ( ) $11,CcSQCCcsC S C DQSsoCcQ Q Q????????????????????????????? ? ????? ? ??? ? ??Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall 1655 1 .6 m oni t or s p e r day15 day s0. 4 m oni t or s p e r day2. 05 ( f or a 9 8% se r vic e le ve l)dLdZ?????Example Problem Solution Computer Products Store (1 of 2) ? Sells monitors with daily demand normally distributed with a mean of monitors and standard deviation of monitors. Lead time for delivery from supplier is 15 days. ? Determine the reorder point to achieve a 98% service level. ? Step 1: Identify parameters. Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall 1656 Example Problem Solution Computer Products Store (2 of 2) Step 2: Solve for R. ( 1. 6 ) ( 15 ) (2. 05 ) ( .0 4 ) 1524 3. 18 27 .1 8 m onit or sR d L Z Ld?? ? ? ?? ? ?Copyright 169。 2022 Pearson Education, Inc. Publishing as Prentice Hall