BPMN to deontic BPMN: A trusted model transformation

• Christine Natschläger
• Felix Kossak
• Klaus-Dieter Schewe

The Business Process Model and Notation (BPMN) is a widely-used standard for process modelling. A drawback of BPMN, however, is that modality is implicitly expressed through the structure of the process flow but not directly within the corresponding activity. All activities are obligatory, and whenever something should be permissible, a gateway or event is used to split the process flow to offer the possibility to execute the activity or to do nothing. This requires a comprehensive understanding of the whole process to identify obligatory and permissible activities. Thus, an extension of BPMN with deontic logic has been proposed in previous work, called Deontic BPMN. Deontic BPMN reduces the structural complexity of the process flow and increases the readability by explicitly highlighting the modality. A comparison of BPMN and Deontic BPMN within a preliminary survey showed an improvement in understandability. In addition, an algebraic graph transformation from a subset of BPMN to Deontic BPMN, called DeonticBpmnGTS, has been defined. The goal of the current research is to show that the graph transformation from BPMN to Deontic BPMN is terminating and confluent, resulting in a globally deterministic transformation. Moreover, the semantic equivalence of BPMN models and the respective Deontic BPMN models is proven based on Abstract State Machines (ASMs). Thus, DeonticBpmnGTS can be called a trusted model transformation.