Hierarchical abilities of diagrammatic representations of discrete event simulation models

Diagrammatic models are a particular class of conceptual models which enable representation of models in two dimensions. Besides, this type of model typically uses a limited number of symbols and thus enables easier model comprehension as well as better communication between modellers and their clients. One of the powerful features of diagrammatic modelling is its capability to enable hierarchical modelling. Advantages of hierarchical modelling are to enable easier modelling of complex systems by using top-down model design and permitting information hiding. In this paper technical capabilities of several diagrammatic modelling methods (augmented Petri nets, activity diagrams and activity cycle diagrams) for using hierarchical modelling are demonstrated. Top-down model development with diagrammatic modelling techniques is illustrated on a comprehensive example of modelling airport passenger building operations. Arguments for using hybrid model development are presented as well.