Emergency Room (ARENA PROGRAM)

Patients arrive to a 24 hour, 7-days-a-week emergency room, the interarrival times (in minutes) are shown in the included data file and the first patient arrives at time zero. All patients that arrive, first sign in with one of the two available receptionists. When they sign-in they are assigned a rating of 1-3, depending on the severity of their illnesses, the probability of each category is 18%, 35% and 47% for 1,2 and 3 respectively. Patients in category 1 are the most severe and are served first in the Nurses Station, Ex Room and Lab and X-ray while patients in category 3 are served last.

Once they have signed-in they have different probabilities for going to the available stations, those probabilities and the time spent in each station (in minutes) are shown in the table below.

From/to	Nurses Station	Ex Room	Lab and X-ray	Check out	Service Time
Sign in	15%	45%	40%	-	TRIA(1,4,8)
Nurses Station	-	65%	30%	5%	TRIA(2,5,7)
Ex Room	5%	-	10%	85%	TRIA(4,7,13)
Lab and X-ray	28%	60%	-	12%	TRIA(10,15,30)
Check out	-	-	-	-	TRIA(3,5,8)

There are three identical ex rooms with one doctor in each, there are two people serving in the Lab and X-rays station and two nurses in the Nurses station. When people go to the X-rays station there are two machines that are needed for the procedure (additional to the people) these machines have a failure that makes them restart every expo(3) hours and it takes UNIF(10,15) minutes to have them working again (the machines stop working even if they are being used). All patients eventually go through the checkout station where the same receptionists will serve them, and they go home.

Nurses, receptionists, lab workers and doctors work 12 hours shifts and they have two 30 min staggered breaks, the first one four hours into their shift and the second one eight hours into their shift. If they are busy when its break time, they finish what they are doing and then they leave and take the full time of their break.

Run 30 replications of a 7 days simulation 7 days, and collect the following statistics:

1. What is the average number of patients present in the system? (include the confidence interval)
2. How many patients of each category were received? (include the confidence interval)
3. In the first replication, what percentage of the time, the X-ray machines spend restarting? Would you recommend them to fix them?
4. Is the priority of the queues making a difference in the average total time of patients rated 1 compared to patients rated 3?
5. If you could afford to add resources, where is the need most pressing and why?

1. The database is properly fitted (10 points)
2. The model is complete; it includes all the required (10 points each).
3. 1. Process
   2. Priority
   3. Schedule
   4. Failures
4. The model has the correct logic structure (15 points)
5. The model runs without any warnings and the simulation time is set correctly (10 points).
6. The student answers correctly questions a-e (5 points each).