Extending discrete event simulation by adding an activity concept for business process modeling and simulation

We show how a basic discrete event simulation language can be enabled for business process modeling and simulation by adding an activity construct. While activities are often not considered at all or not treated in a conceptually satisfactory way in the discrete event simulation literature, the great majority of business process modeling languages are based on an activity construct. However, unlike a simulation language, the predominant business process modeling languages, including UML Activity Diagrams and the Business Process Modeling Notation (BPMN), are not executable. So, the challenge for business process modeling is to define an executable semantics for activities, while the challenge for discrete event simulation is to find a way how to introduce an activity construct on top of the basic discrete event simulation concepts of objects and events. The main idea is to define an activity as a complex event having a start event and an end event. This idea is well-known from the business process modeling literature, e.g. from the Business Process Definition Metamodel (Bock 2008), but it has also been used in a rudimentary way in some discrete event simulation approaches, e.g. in (Fishman 2001). Our research contribution consists of two achievements: 1) we define a conceptual model of activities for discrete event simulation and implement it in our ER/AOR simulation language; 2) we show how to use BPMN for the purpose of simulation modeling.