1. Jack's Refrigeration Repair Service is under contract to repair, recondition, and/or refurbish commercial and industrial ice-makers from restaurants, seafood processors, and similar organizations. Jack currently has five jobs scheduled, shown in the order in which they arrived.
Job Processing Time (hours) Due (hours)
V 20 50
W 10 35
X 50 90
Y 15 35
Z 55 75
a. Complete the following table. (Show your supporting calculations below).
b. Which dispatching rule has the best score for flow time?
c. Which dispatching rule has the best score for work-in-process (jobs in the system)?
d. Which dispatching rule has the best score for lateness?
e. What dispatching rule would you select? Support your decision.
Dispatching Rule Job Sequence Average
Flow Time Average Number of Jobs Average Lateness
2. The president of a consulting firm wants to minimize the total number of hours it will take to complete four projects for a new client. Accordingly, she has estimated the time it should take for each of her top consultants -- Charlie, Gerald, Johnny, and Rick -- to complete any of the four projects, as follows:
Consultant A B C D
Charlie 13 16 11 18
Gerald 13 15 10 12
Johnny 15 11 20 15
Rick 17 17 12 22
a. In how many different ways can she assign these consultants to these projects?
b. What is the total number of hours required by the following arbitrary assignment?
Charlie -> B; Gerald -> A; Johnny -> D; Rick -> C
c. What is the optimal assignment of consultants to projects? (Use the assignment method; SHOW YOUR WORK!)
d. For the optimal schedule, what is the total number of hours it will take these consultants to complete these projects?
e. What is the significance, if any, of the fact that Gerald is the best performer at all four projects?
Answers questions on Scheduling and Assignment.