Information and Process Modeling for Simulation – Part I

In simulation engineering, a system model mainly consists of an information model describing a system's state structure and a process model describing its dynamics, including its state changes. In the fields of Information Systems and Software Engineering (IS/SE) there are widely used standards such as the Class Diagrams of the Unified Modeling Language (UML) for making information models, and the Business Process Modeling Notation (BPMN) for making process models. This tutorial presents a general approach, called Object-Event Modeling (OEM), for Discrete Event Simulation modeling using UML class diagrams and BPMN-based process diagrams at all three levels of model-driven simulation engineering: for making conceptual domain models, for making platform-independent simulation design models, and for making platform-specific, executable simulation models. In our approach, object and event types are modeled as special categories of UML classes, random variables are modeled as a special category of UML operations constrained to comply with a specific probability distribution, and queues are modeled as ordered association ends, while event rules are modeled both as BPMN-based process diagrams and in pseudo-code. In Part II, we will discuss the more advanced OEM concepts of activities and GPSS/SIMAN/Arena-style Processing Networks, while in Part III we will further extend the OEM paradigm towards agent-based modeling and simulation by adding the concepts of agents with perceptions, actions and beliefs.