Simulation Systems Modeling (Software used: Rockwall ARENA) concepts

1. Give the ARENA model for a processor where there the maximum queue length is 4; arriving customers who find the the queue is full return 2 to 4 hours later. Arrivals to the system are exponential with a mean of 20 minutes; server processing times are normal with a mean of 19 and a standard deviation of 5 (these times are in minutes also).

2. For problem 1, consider the situation where no customer can depart and then return later; will server utilization be different or the same for the two cases -- the first where customers leave and then return, the second where customers stay? Explain.

3. Explain briefly for ARENA:

a. How to specify the time that an Arena model is shut down

b. How to model in Arena two servers working in parallel where either server can process a customer

c. How to obtain last in, first out order of serving customers.

please help its concepts based and drawing Thanks!