Presem - Preserving Semantics During Refinement of Business Processes
The project’s most significant results of the conducted research comprise the following activities: (i) development of a formal business process model on the basis of abstract state machines (ASMs) as well as validating the resulting ASM ground model against the (informal) requirements of the BPMN 2.0 specification and (ii) horizontal and (iii) vertical refinements of the ASM ground model by preserving the operational semantics during all refinement steps.
Starting from textual descriptions in the BPMN 2.0 specification, in close cooperation with the long-term research project Vertical Model Integration (VMI) at the SCCH, each BPMN element was mapped to a corresponding ASM transition rule. Thereby, several ambiguities in the specification regarding the semantics of dynamic models, such as messaging, inclusive merge (OR), or the instantiation concept, were revised due to the mathematical exactness of ASMs as the formal basis.
The horizontal refinement of the ASM ground model implies the extension of the BPMN specification to user interaction, dialogs, and data. Therefore, primarily the activities, control flows in diagrams, and communication aspects were observed. The actual extension is based on a typed, technology-independent approach for integrating workflow definitions and application programming called workflow charts. The semantics of workflow charts was formalized and validated by applying ASMs. The concept of ASM refinement also serves as the formal basis for vertical refinement of the ground model towards an executable specification. That is, the ASM refinement method guarantees transformations of higher-level specifications into more concrete specifications without changing the semantics at the higher level of abstraction.
The vertical refinement of the ASM ground model implies adding implementation oriented specifics needed for the execution. The primary focus was put on the control and the event flow, the main two parts of the BPMN specification needed to execute a minimal BPMN workflow. Additional concepts, which concretize the execution of the semantics defined on higher levels, were added targeting filling gaps between the high level model and an implementation.
Implications of the conducted research can be expected in particular for the technological area. The comprehensive and sound business process specification methodology will contribute to resolve a lot of today’s error sources in business process implementation projects. Techniques and tools can be adjusted accordingly with the effect that semantics of business processes cannot be lost or changed during refinement steps by working within this tools and techniques. This definitively constitutes a big step towards semantically correct business process implementations.
A.Univ.-Prof. Dr. Josef Küng
Prof. Dr. Klaus-Dieter Schewe
Dr.in. Verena Geist
Jan Kubovy, MSc