Page 209 - ExtendSim User Guide
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Scheduled Time model
For example, assume that a worker normally takes 5 minutes to perform a task, but takes 5.25 minutes to do the task after doing it for 6 hours. To do this, connect a Lookup Table block (Value library) to the D input of the Activity block as shown in the following model.
Scheduled Time model
The Lookup Table block is set to Lookup the: time. Data that represents the worker’s day is entered in the Hours column; the time to perform the task is entered in the Task Time column. As indicated in the Lookup Table’s dialog, a portion of which is cloned onto the model work- sheet, the time to perform the task changes at hour 6.
Lookup Table block’s time units
Notice that the time unit for the Hours column in the Lookup Table’s dialog is hours and that the time the worker takes to perform the task (Task Time column) is in minutes. The time units for the model are hours, so the first column must be in hours. However, since the output of the Lookup Table block is connected to the D connector of the Activity block, the Task Time col- umn should be defined in the same time units (minutes) that are used for the Activity’s Delay parameter. For this model, at a particular hour of the day (Hour column) an activity will take a specified number of minutes to perform the task (Task Time column). Time unit consistency is discussed in “Choosing time units for the columns” on page 123.
Random processing time
A common requirement for activities is to set a random processing or delay time. This is easily accomplished by selecting a distribution in an Activity block.
Random Activity model
In the dialog of the Activity block, select the appropriate distribution, for example Normal, and specify the value of the parameters, such as a mean of 2 and a standard deviation of 0.2. The
Processing 183
Setting the processing time
Discrete Event

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