Problem 6.7) Write a BOSS program to simulate the dredging/hauling/dumping job described below.
The dredge shown is being used to deepen the Intercoastal Canal between Galveston and Corpus Christi. The hold of the dredge has a capacity of 2000 cubic yards. The dredge bucket has a capacity of about 60 cy (by about, I mean that when dredging, it carries a mean of 60 cy, sometimes more, sometimes less, normally distributed, with sometimes (but rarely) as little as 50 cy, and sometimes (rarely) as much as 70 cy.) The time it takes the bucket to be positioned, lowered, filled, raised, and emptied into the hold is from 3 to 5 minutes normally distributed.
If the hold of the dredge is ever filled to capacity, the operator stops dredging for 15 minutes. After waiting she then checks to see if barges have unloaded at least half of her capacity, and if so she begins dredging again. If not, she waits another 15 minutes and checks again.
There are two barge unloading positions against the dredge.
There are 5 barges employed on this job. Each has a hold capacity of 160 cy. They require a mean loading time of 30 minutes, with sigma = 4 minutes, and a mean unloading time at the riverbank of from 8 to 10 minutes uniformly distributed. It takes a barge from 20 to 24 minutes to travel from the dredge to the riverbank when loaded, and from 8 to 10 minutes to return, both normally distributed.
When the barges come up to the dredge, the captains are instructed to keep away unless there is a minimum of 400 cy in the hold of the dredge. This keeps the barges from getting in the way when the dredge does not have sufficient material to fill the barge, and also provides some dredge material to assist in stabilizing the dredge.
OSHA regulations require that before each dredge scoop, the dredge operator check for boats coming down the canal. If a boat is sighted, the operator must delay the next dredge scoop until the boat has passed. Boats come down the canal exponentially distributed with a mean of 1 hour, and it takes them from 4 to 16 minutes, distributed normally, to pass. Barge operations are not affected by these boats, and they may continue to work.
Study the system for 5 days, working 24 hours a day.
- First, take all the variation out of the model. In other words, your first run should have a dredge bucket capacity of exactly 60 cy (set sigma = 0), the time to load it 4 minutes exactly, barge loading time exactly = 30 minutes (sigma = 0), boats coming down the canal = 1 hour exactly, etc.
- Second, put the above stated variations back into the model and re-run it.
No hand solution.