Modeling How-To's > Modeling Activities > Attribute-Based Activities

Attribute-Based Activities

The activity time or other activity action is based on the value of a particular attribute. (For routings based on activity attributes see Conditional Routings.)

 

The model used for this example, as well as all of the modeling "how-to" examples, can be found in the ProModel Solutions Café (http://www.promodel.com/solutionscafe/howto/). A video demonstrating this solution can be found here.

Solution

  1. Define at least one entity attribute and make sure it gets assigned a value somewhere in the model (see Working with Variables and Attributes).
  2. Click on the Logic button in the activity Properties dialog.
  3. Define an IF statement to test for the attribute value.
  4. Define a WAIT statement with the desired time for the attribute value being tested.
Example

Moldings entering an Inspect and Clean operation are either defective or non-defective. The activity time for defective molds is normally distributed with a mean of 2 minutes and a standard deviation of .5 minutes. Non-defective molds have a mean activity time of .6 minutes with a std. dev. of .2 minutes.

Solution

  1. Define an attribute and make sure it gets assigned a value prior to entering the activity where it is going to be evaluated (see Working with Variables and Attributes)
  2. The Logic Builder for the Inspect and Clean operation shows that an IF statement has been defined which checks whether the attribute value called aDefective_Molds is equal to 1 (1=defective).
  3. If true, a WAIT time of N(2, .5) minutes is defined.
  4. An ELSE statement is defined for molds that are non-defective (i.e., aDefective_Molds = 0)
  5. For this case a WAIT time is defined for N(.6, .2) minutes.

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