1 An Analytical Evaluation of BPMN Using a Semiotic Quality Framework Terje Wahl & Guttorm Sindre NTNU, Norway Terje Wahl, 14. June 2005

2 Agenda –Motivation –Related work –BPMN –Semiotic Framework for Evaluation of Quality –Evaluation (Results) –Future work –Conclusion Terje Wahl, 14. June 2005

3 Motivation –Modelling languages are abundant –Many overlapping concepts –Difficult to select –Evaluation of languages is important to –select most suitable –improve the language –We have performed an evaluation of BPMN –Analytical –According to the Semiotic Quality Framework Terje Wahl, 14. June 2005

4 Related work –Semiotic Framework has been used to evaluate –quality of UML –comparison of ontology languages and tools –evaluation of five enterprise modelling languages (using a tailored semiotic framework) –Other published papers evaluating BPMN –...is hard to find –BPEL4WS has been evaluated –Relevant because of easy mapping from BPDs Terje Wahl, 14. June 2005

5 BPMN –BPMN = Business Process Modelling Notation –BPMN defines Business Process Diagrams (BPD) –Create graphical models –Models business processes and their operations –Based on a flowchart technique –Aims to be –easy to understand and use also for business users –easily translated into executable code –BPMN 1.0 specification was released May 2004 Terje Wahl, 14. June 2005

6 BPMN - Basic Notation –Graphical elements in four categories: –Flow objects –Connecting objects –Swimlanes –Artefacts Terje Wahl, 14. June 2005

7 BPMN - Examples © Stephen White, IBM. Terje Wahl, 14. June 2005

8 BPMN – Examples (2) © Stephen White, IBM. Terje Wahl, 14. June 2005

9 BPMN – Examples (3) © BPMI.org Terje Wahl, 14. June 2005

10 BPMN vs. BPEL4WS –BPEL4WS = Business Process Execution Language for Web Services –Specification for specifying processes –Executable XML-format –Activities are implemented by Web Services –BPDs can be easily mapped to BPEL4WS –With a few exceptions Terje Wahl, 14. June 2005

11 Semiotic Framework –For understanding and evaluating quality of –conceptual models –conceptual modelling languages –Based on linguistic and semiotic concepts –(such as syntax, semantics and pragmatics) –enable the assertion of quality at different levels –Based on a constructivistic world-view –Participants have different world-views Terje Wahl, 14. June 2005

12 Semiotic Framework (2) –Evaluate the modelling language's potential for making models of high quality –Evaluate two kinds of criteria –the conceptual basis of a language (e.g. metamodel) –the external (graphical) representation of the language –Five aspects are identified for evaluating the quality of conceptual modelling languages: Terje Wahl, 14. June 2005

13 Semiotic Framework (3) Terje Wahl, 14. June 2005

14 Evaluation (Results) Next slides: –Domain Appropriateness –Participant Language Knowledge Appropriateness –Knowledge Externalizability Appropriateness –Comprehensibility Appropriateness –Technical Actor Interpretation Appropriateness Terje Wahl, 14. June 2005

15 Domain Appropriateness –Central concepts: Process and Activity –BPMN has a Functional perspective –Well suited to model processes with activities and (advanced) rules for flow of sequence –Also show actors/roles performing activities –Designed for modeling processes within business domain Terje Wahl, 14. June 2005

16 Domain Appropriateness –Limitations outside the functional perspective e.g. –Object-oriented models (no class hierarchy etc.) –Organizational structures & resources –Business strategies –Limitations outside the business domain –No problem if using the same concepts –But lacks concepts for e.g. valves and pumps for modeling control engineering processes –BPMN has possibilities for extending the language Terje Wahl, 14. June 2005

17 Participant Language Knowledge Appropriateness –Clear and concise definition of graphical elements –Many similarities to UML Activity Diagrams, Flowcharts, Data Flow Diagrams and others –Goal for BPMN to be easily understandable –Also for business analysts! –Unrealistic? Because of complex advanced features Terje Wahl, 14. June 2005

18 Participant Language Knowledge Appropriateness –Example of complexity: 23 types of events Terje Wahl, 14. June 2005

19 Knowledge Externalizability Appropriateness –Highly dependable on the specific knowledge of the actors –Difficult to evaluate in a general way –If relevant knowledge goes beyond the domain of business processes? –Hard to externalize relevant knowledge using only BPDs –Language extensions may work for some cases Terje Wahl, 14. June 2005

20 Comprehensibility Appropriateness –Understanding of language concepts and notation –BPMN provides notational categories –Readers can easily recognize the basic types of elements –The basic categories contain variations that may be used when creating more complex BPDs –Categories are easily distinguished from one another –Familiar symbols  Helps with the comprehensibility of BPDs Terje Wahl, 14. June 2005

21 Comprehensibility Appropriateness (2) –Few rules for layout of diagrams –Potential for poor empirical quality –Aggregation of Activities is supported –Helps to understand and get an overview Terje Wahl, 14. June 2005

22 Technical Actor Interpretation Appropriateness –BPDs are easily mapped into BPEL4WS –A few exceptions –Guidelines in the BPMN Specification –BPEL4WS requires WSDL and Web Services to be executable. –Processes must in these cases be suitable for implementation using a combination of Web Services. –Atomic Activity in BPDs  Web Service Terje Wahl, 14. June 2005

23 Future work –Evaluate further aspects of BPMN –Quality of metamodel, documentation and tool support –Empirical evaluation –Especially for validating these findings –Comparative studies –To several other BPM languages Terje Wahl, 14. June 2005

24 Conclusion –BPMN well suited for modelling business domain –Limitations to other domains –BPMN has easy basic graphical notation –But complex features require training (for non-technical users) –BPDs are fairly easy to understand –Categorization of graphical elements –Support for aggregation of activities –BPDs are easily mapped to BPEL4WS –But requires creating Web Services representing Activities Terje Wahl, 14. June 2005

25 Questions/comments? –You can also reach me at Terje Wahl, 14. June 2005

26 BPMN - Basic Notation –Flow objects: –Event –Activity –Gateway Terje Wahl, 14. June 2005

27 BPMN - Basic Notation –Connecting objects: –Sequence flow –Message flow –Association Terje Wahl, 14. June 2005

28 BPMN - Basic Notation –Swimlane objects: –Pool –Lane Terje Wahl, 14. June 2005

29 BPMN - Basic Notation –Artefact Elements: –Data object –Group –Annotation Terje Wahl, 14. June 2005

30 The BWW ontology –Identify ontological discrepancies by looking at –Construct Overload, Construct Redundancy, Construct Excess, Construct Deficit –Complements analysis with Semiotic Framework –Semiotic Quality Framework –More general –BWW Ontology –More concrete - suggests which concrete language constructs should be used –Future Work: Compare BPMN Metamodel to BWW Ontology Terje Wahl, 14. June 2005