  This work presents a fully elaborated ontology, defined via the Ontology Web
Language (OWL), of the Business Process Model and Notation (BPMN) standard to
define business process models, and we demonstrate that any BPMN model can be
serialized as OWL file. Based on ontological analysis and a corresponding
definition of a modeling notation as ontology we show that business process
models can be transformed from one notation into another one as long as there
are common underlying concepts; this is demonstrated with the case of an actor
based, or subject-oriented, view on business processes. Furthermore, a
reference architecture for Workflow Management Systems (WfMS) based on
microservices is discussed which is capable of executing actor based business
process models. As a transformation of BPMN models into the actor based view is
generally possible, also BPMN models could be enacted. As a result, we can
conclude that the actor system is a promising way to stimulate new ways to
design workflow management systems and to design business process modeling
languages which are more comfortable to use by non-experts without losing
necessary expressiveness. Another result is that an ontology is a productive
way to define a modeling notation as it can be used as knowledge base, it is a
formal conceptualization of the underlying notions, and can be semantically
enriched for further use.
