Note that Figure 7-7 also shows Activity Derivation Element. As with the previous sections of the enterprise model, some Activity Characteristics (specifically Continuous Activity Characteristics) are derived from other Activity Characteristics.
For example, the “Actual Duration” of an Activity is derived by subtracting the Actual End Date from the Actual Start Date. This is shown using the Reverse Polish Notation approach in Table 7-3.
There, to calculate “Actual Duration” for an instance of Activity, the first element is “Actual End Date”, and the Operator is “add”. Thus, the “Actual End Date” of the Activity Characteristic Value to describe the Activity involved is added to the registry. The second element is “Actual ...