A military ground force maintains a forward position and a rear depot 22 miles away to supply it. There is a single commodity that is consumed at the forward position and resupplied to it from the rear supply depot; the commodity could be anything (ammunition, fuel, food, etc.). Initially, there are 28 units of supply at the forward position (the commodity is in integer-valued units). Demands occur through time at the forward position, with inter-demand times being exponentially distributed with mean 1 hour; the f rst demand occurs not at time 0, but after one of these inter-demand times after time zero. When a demand occurs at the forward position it is for 1, 2, 3, …, 10 units of the commodity with respective probabilities 0.05, 0.07, 0.11, 0.04, 0.14, 0.13, 0.25, 0.03, 0.13, and 0.05. After the demand occurs, if the forward supply is still more than s , nothing is done about replenishing; s is a f xed parameter of the model, and assume that it has a value of 15. However, if the forward supply after the demand occurs is s or below, a reorder message is sent to the rear supply depot immediately after the time of the demand. (By the way, the supply level at the forward position could become negative, representing a backorder that will be satisf ed later by future resupply.) The amount ordered is where S is a f xed constant, equal to 45. The rear depot has a single clerk that processes orders in TRIA(30, 45, 90) minutes, and orders form a FIFO queue for this clerk. Next, a truck is requested to transport the order to the forward position; there are two trucks, each of which can carry only one order at a time regardless of the order’s size, and orders form a FIFO queue for a truck. It takes between 10 and 20 minutes (uniformly distributed) to load an order onto a truck. The trucks travel at 35 miles per hour in each direction. When the truck arrives to the forward position, it takes between current forward supply total amount of resupply on order from previous orders but not yet delivered to the forward posisition S 2 2 ( ) ( ) kel01315_ch08_345-378.indd 377 17/12/13 2:07 PM 378 Chapter 8 5 and 10 minutes (uniformly distributed) to unload the truck, then the resupply occurs by incrementing the forward supply by the size of this order, and the amount on order is decremented by the size of this order. The simulation is to run for 30 round-theclock days. Make a plot of the forward supply as a function of time, similar to that of Model 5-4, with red versus black curves; also animate truck movements, queues, and resources. Get the average of the forward-supply level. Also, collect the percent of time that there is nothing physically on hand at the forward supply; that is, when the forward-supply level is zero or negative. Make 25 replications, and comment on the results. (HINTS: Depending on how you do this, you made need a “fudge” factor consisting of a small delay to break a time tie properly between two simultaneous events involved in placing an order. Also, you may want to look at the Separate module in the Basic Process panel, which can “clone” an entity.)