III. LITERATURE SURVEYMany researchers have studied the transformation between BPMN and BPEL. Most of the research conducted in this field is analytical in nature. There are only a few insights into the practical use of BPMN. In particular, the work of Ouyang et al. [10, 11] and [12], who propose that the transformation from BPMN to BPEL is performed by matching multiple steps of pattern and graph transformation. An algorithm to generate readable BPEL code from the BPMN model is presented in [10] which generates BPEL code from the BPMN model by discovering structural patterns in the BPMN models which in turn are mapped into BPEL structured tasks. The original BPD is decomposed into well-structured components having an entry point and an exit point. The automated BPDs are then incrementally transformed into BPEL blocks. For example, a component having a purely sequential structure is mapped into the BPEL sequence construct, while a component containing a parallel structure is mapped into the flow construct. The BPEL generation algorithm also transforms the unstructured subset of the BPMN model by leveraging the BPEL event handler construct. As a result, any BPMN model consisting of tasks, events, parallel gateways, and XOR gateways (both data- and event-based) connected in arbitrary topologies can be mapped to BPEL. In contrast, a model with unstructured topologies or with constructs such as OR-join and complex gateway cannot be mapped to BPEL. Furthermore, the BPEL generation algorithm only translates a smaller set of captured models into the main subset of the BPMN model by applying some restrictions, such as each cycle must have a single entry and exit point, on the original model. A well-formed main BPD may contain components that are not well structured, for example loops with...... middle of paper ......Rosemann et al., “How good is BPMN really? Insights from theory and practice”, 2009.[17] M. Rosemann, P. Green, M. Indulska et al., “Using ontology for representational analysis of process modeling techniques,” International Journal of Business Process Integration and Management, vol. 4, no. 2, 2009.[18] T. Wahl and G. Sindre, “An Analytical Evaluation of BPMN Using a Semiotic Quality Framework,” Advanced Topics in Database Search: Volume 5, pp. 94, 2006.[19] G. Decker and J. Mendling, “Instantiation semantics for process models”, Proceedings of the 6th BPM, Milan Italy, pp. 164-179, 2008.[20] P. Wong and J. Gibbons, “A process semantics for BPMN,” Formal Methods and Software Engineering, pp. 355-374, 2008.[21] M. Muehlen and J. Recker, "How Much Language is Enough? Theoretical and Practical Use of Business Process Modeling Notation." page. 465-479.