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Operations Research Models and Methods
 
Problems Section
Problems for Queueing Models
 - Computer Queue

A group of 10 students share 2 computers. For each student the following is true: events that require a computer occur at the rate of 0.5/hour, the average time per computer use is 20 minutes. Both service and arrival processes are Poisson. When a student tries to use a computer and finds them both busy, the student wastes his or her time watching television.

Some results of the queueing analysis are shown below.

 

Quantity
Value
Units
Mean Number in System
1.912
students
Mean Number in Queue
1.486
students
Mean Number in Service
1.791
students
Throughput Rate
3.582
students/hour
Efficiency
0.674
 

a. Write the Kendall notation describing the system.

b.What proportion of the total computer time are the computers idle?

c. What proportion of the time are students wasting time watching the TV?

d. If another student is allowed to share the system (making 11 in all), how will the Efficiency change? (up, down, or stay the same)


  
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