Jack's Refrigeration Repair Is Under Contract to Repair, Recondition, And/or

question 41

Essay

Jack's Refrigeration Repair is under contract to repair, recondition, and/or refurbish commercial and industrial icemakers from restaurants, seafood processors, and similar organizations. Jack currently has five jobs to be scheduled, shown in the order in which they arrived.
$$\begin{array} { | c | c | c | } \hline \text { Job } & \text { Processing Time (hours) } & \text { Due (hours) } \\\hline \mathrm { V } & 20 & 50 \\\hline \mathrm { W } & 10 & 35 \\\hline \mathrm { X } & 50 & 90 \\\hline \mathrm { Y } & 15 & 35 \\\hline \mathrm { Z } & 55 & 75 \\\hline\end{array}$$
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.
$\begin{array}{|c|c|c|c|c|}\hline\begin{array}{c}\text { Dispatching } \\\text { Rule }\end{array} & \text { Job Sequence } & \begin{array}{c}\text { Average Flow } \\\text { Time }\end{array} & \begin{array}{c}\text { Average } \\\text { Number of } \\\text { Jobs }\end{array} & \begin{array}{c}\text { Average } \\\text { Lateness }\end{array} \\\hline \text { FCFS } & \\\hline \text { SPT } & \\\hline \text { EDD } & \\\hline \text { CR } & \\\hline\end{array}$

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Definitions:

Time-Series Graph

A graphical representation showing how a set of data points change over time.

Unemployment Rate

The unemployment rate measures the percentage of the labor force that is jobless and actively looking for employment.

Decreased

Pertains to a reduction in amount, size, intensity, or number.

Time-Series Graph

A graphical representation showing how a given data set changes over time.