The default PMCube data model also requires the definition of aggregation functions, which are applied to the simple attributes during the aggregation of events. These aggregation functions can be defined on the \textit{Aggregation Functions} tab.
From the drop-down menu on top of the tab, you can select the default aggregation function, that will be applied to all simple attributes in the case of event aggregation. If you want to choose another aggregation function for a particular simple attribute, you can click on 
. A pop-up window will show up, where you can map the simple attribute to an aggregation function. The mapping between the simple attribute and the aggregation function will be added to the list. You can click 
or 
to remove or edit the selected mapping.