Page 175 - ExtendSim User Guide
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Queueing 149
Sorting items using the Queue Equation block
(The example includes a second model, with a FIFO queue instead of a Queue Equation block, for comparison purposes.)
Minimize Setup model
Maximizing service levels
In a service system, the service level can be defined as the number of customers served within a certain time period. For instance, technicians might be rated on the percentage of customer requests fulfilled within a certain time period. To maximize this, a queue that applies the maxi- mize service level rule gives priority to those customers who waited less than the service level time, leading to dramatic improvement in the service level. However, this type of system might not be popular with real-life customers since some of them may have to wait a very long time while other customers who arrived later would wait a much shorter time.
Maximize Service Level model
The top section of the Maximize Service Level model uses a Queue Equation block to sort the queue into two priority levels:
• The service priority is the customer who has spent the longest time (but less than 10 min- utes) in the queue
• Customers who have waited longer than 10 minutes are placed at the back of the line
The lower section of the model is exactly the same as the top, except it uses a Queue block in FIFO sorted queue mode. As the model is run, two plotters show the effect on service level and wait time. Comparing the service level of the upper model to the bottom model, it is obvious that there is a dramatic improvement if the sorting rule is used. However, the second plotter
Discrete Event

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