Comparing BPMN to BPMN + DMN for IoT process modelling: a case-based inquiry

The network of interconnected devices that compose the Internet of Things (IoT) continues to expand. Business processes are starting to take advantage of IoT by adapting to the physical environment or by automating process tasks. The Business Process Model and Notation (BPMN) specification has been employed in numerous studies to include IoT devices and resources. While aggregating low-level IoT data into process-relevant data is of paramount importance for IoT processes, BPMN may not be the best approach to model this data aggregation. Decision Model and Notation (DMN), however, is a recently introduced standard which is inherently used to aggregate low-level information into high-level information. This makes DMN a promising match for modelling context data aggregation in IoT processes. Therefore, this paper examines the modelling of IoT processes by comparing the standard BPMN approach and the combination of BPMN and DMN. Three cases with increasing need for context aggregation are modelled according to both techniques, leading to an analysis of the capability of the approaches to support IoT processes in terms of high-level context-awareness, scalability and complexity, flexibility, and decision logic reusability. We demonstrate that in cases where a need for complex context aggregation decision logic is present, the combination of BPMN and DMN provides the required support, even for the complex cases, and performs better than BPMN on its own.