DC Cafeteria Simulation

Exit

Exit

Entrance

Mr. SubChopsticks

Manager of DC caf would likea simulation of the customeractivity in a day. You are giventhe simplified model at left.

Customers arrive at Entranceand 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 simulatehow the cafeteria operates?

S1

S2 S3

S4

S5

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?

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

Simulating Conversation

Time Event S1 S2 S3 S4 S5

0

3

4

8

9

10

-

goes to Mr. Sub

goes to Mr. Sub

leaves Mr. Sub, goes to cashstarts service

goes to Chopsticksleaves Mr. Sub, goes to cash

….

- - - -

- - -

- - -

- -

-

3(3+0)

4(1+3) 8(5+3)

9(5+4) 8*

9*

10*

9(1+8) 10(2+8)

12(3+9) 14(5+9) 10(1+9)

Note: Bold numbers are randomly generated time intervals. ‘*’ denotes time value carried over from before