DC Cafeteria Simulation

1
DC Cafeteria Simulation
Manager of DC caf would like a simulation of the
customer activity in a day. You are given the
simplified model at left. Customers arrive at
Entrance and do one of 3 things 1. Order and
pick up food at Chopsticks and proceed to one
of two cashiers 2. Order and pick up food
at Mr. Sub and proceed to one of two
cashiers 3. Proceed directly to one of two
cashiers to add money to their WatCard What
is a good way to simulate how the cafeteria
operates?
S2
S3
S4
S5
S1
2
Simulation Questions
What is the longest the line gets at the deli
counter? On average, how much time does a
customer wait for Chinese food? What is the
shortest amount of time a customer passes through
the entire system? What percentage of time is the
cashier busy during the late afternoon? How does
the business of exam periods affect the
line-up? If fire regulations permit a maximum of
50 people in the food court at one time, how many
people must be turned away or forced to wait
outside in the cold?
3
Simulation Assumptions

• Customers randomly choose a cashier
• Customers may have to wait, but only in one of
  the marked lines
• Activity in system will be tracked through events
• 5 events make up the system
• customer arrival (special case)
• completion of service at Mr. Sub, completion of
  service at Chopsticks
• completion at cashier 1, completion at cashier
  2
• Start of service is not considered an event

4
Simulating Conversation
Note Bold numbers are randomly generated time
intervals. denotes time value carried over
from before
Time
Event
S1
S2
S3
S4
S5
0
-
-
-
-
-
3(30)
goes to Mr. Sub
-
-
-
4(13)
8(53)
3
goes to Mr. Sub
-
-
-
9(54)
8
4
leaves Mr. Sub, goes to cash starts service
-
-
9
9(18)
10(28)
8
-
10
12(39)
14(59)
10(19)
9
goes to Chopsticks leaves Mr. Sub, goes to
cash
.
10