WORKSHEET 2 (THE DRILL _2)

Modify the drill problem (WORKSHEET 1) such that the time between arrivals is exponential with means of 10 and 6 for job types 1 and 2 respectively. The processing times are uniformly distributed between 2 and 6 for job type 1 and between 1.5 and 4.5 for job type 2.

Also collect statistics on the drill utilisation, number in the queue, job flow time, and time between job exits.

New blocks & statements to include :

TALLY: Mark, Interval, Between, The statistical functions.

New experimental statements to include :

DSTATS, TALLIES.

Additional Work

1. Re-run the model using different random number streams.

2. Save the queue length to a disc file and run the output processor to examine the time variation of queue length, Use the PLOT statement to get a presentation standard output. NOTE: It is not a good idea to attempt to print the results of using the PLOT command because ARENA will only produce a screen dump which is always of a rather indifferent quality. It is far better to export the PLOT data to a spreadsheet package such as Microsoft EXCEL which has good graphics printing capabilities.

Results

Your model should give close to the following results :

Number of type 1 jobs = 43

Number of type 2 jobs = 71

Drill utilisation = 78.9%