Customer (1') a 1; 0.41 1.12 058 418 5.37 4.53 1.02 5.42 0.82 0,26 o (b) 4 PTS Using an event-centric perspective, consider the state variable: number of cus tomers in the caf (N); simulation variables: simulation time (1), time of next arrival (t4). and time of next departure (lg); and counter variables: number of arrivals (NA), number of departures (ND), and total wait time (WT) @mOSO'AWNH ._. o Initialize . . WT += N ' (mm(tA, t9) _ t) t = "\""(t't' (c) 2 PTS Choose either the customer-centric or event-centric perspective and explain how a maximum queue capacity of 5 customers could be enforced. Modify an activity diagram to support your answer (0K to screen-capture and edit existing diagrams). 6.2 Logistics for Submarine Upgrades [15 points] The Navy is upgrading its submarines to take advantage of commercial o-theshelf (COTS) components The sonar system analog-to-digital (A/D) converter is one of the key systems targeted for modernization A random demand (D) for A/D converters required each day is modeled with the discrete PMF below based on records over the past 100 days. d 1701) 2 0.13 3 0.42 More wslomers N\" "'' 5 0.45 customers If there is insufcient inventory, the component is back-ordered (represented as a negative Using the generated inter-arrival periods 1 and service times 1; when needed, follow mvemOYY) and the upgrade Will be completed 011 the next day when inventory is available. the activity diagram to complete the following table to manually simulate the rst ten The A/ D converter supplier orders from a subcontractor in California and hardens for events and nd the average waiting time at the end of the simulation, reliability in the harsh submarine environment. The total lead-time (L) is a minimum of 5 days plus exponentially-distributed shipping delay S with average 1/) : 4 days. W = WT/NA L = 5 + s, 3 ~ exponentialO' = 0.25) Hint: as this etample uses the same model assumptions and identical samples of 1 and Currently, the Navy places an order for 40 A/D converters when its current inventory falls y as part (a), you should obtain the same results! below 30 at the end of the clay. Assume that the purchasing system only allows one pending order at a time. New A/D converters enter inventory and are available for use on the day after delivery. Work only takes place on weekdays (MondayHiday). As the systems project manager for the prime contractor, you are asked to simulate inven- tory levels and anticipate any problems. You are primarily concerned about the cumulative eect of back~ordered A/D converters measured as the total number of productdays with insufcient inventory (penalty) For example, sequential days with 1, 3, and 5 back-ordered converters (71, 73, and 75 inventory) contribute 9 total units of back-order product-days. F. '- 3 ~ (a) 2 PTS Develop a discrete process generator for the daily A/D converter demand (D) using a uniform(0,1) sample 74 and a continuous process generator for the lead time L using a uniform(0,1) sample n. (b) 4 PTS By hand, perform a manual simulation of the inventory system for three work- weeksr Use the provided random numbers rd for daily demands and rJ for shipping delays when needed. Record results in the table below where N is the inventory of A/ D converters at the start of the day, D is the daily demand, P is the cumulative penalty for backeordered converters (i.e., P increases by |Nl if N