Exercise 4-2 from the textbook with extensions (Wednesday, 2/11/09)

(Due Friday 2/13/09)

Do exercise 4-2 from the textbook and the extentions listed below. Submit via e-mail (with Ex. 4.2 in the subject line) a program that will solve Run 7 listed below, and a discussion (an MS-Word document) of the results. The discussion should include a results table that with the average numbers in queue at each process and the total time in system of items for each run. The discussion should include what appears to make the results different, and the importance of knowing the correct distributions in queues. Just e-mail the program and the discussion to me. The grading sheet is a separate file this time.

Again you may submit this as groups. Make sure the name of each group member is on the discussion summary page and the each member (except the sender) is copied on the e-mail.

4-2 Develop a model of a simple serial two-process system. Items arrive at the system with a mean time between arrivals of 10 minutes, with the first arrival at time 0. They are immediately sent to Process 1, which has a single resource with a mean service time of 9 minutes. Upon completion, they are sent to Process 2, which is identical to (but independent of) Process 1 . Items depart the system upon completion of Process 2. Performance measures of interest are the average numbers in queue at each process and the total time in system of items. Using a replication length of 10,000 minutes, make the following four runs and compare the results (noting that the structure of the model is unchanged and it's only the input distributions that are changing):

Run 1: exponential interarrival times and exponential service times
Run 2: constant interarrival times and exponential service times
Run 3: exponential interarrival times and constant service times
Run 4: constant interarrival times and constant service times

Extend the problem by making the additional runs below using an Erlang distributions. Use ERLA(10/3,3) for interarrivals and ERLA(3,3) for service times.

Run 5: Erlang interarrival times and Erlang service times
Run 6: constant interarrival times and Erlang service times
Run 7: Erlang interarrival times and constant service times