Business Process Modeling with Event-driven Process Chains Jan Mendling Institute of Information Systems and New Media WU Wien
You will learn in this session… • What business process management is, • How business process modeling works, and • What event-driven process chains are.
BPM and Workflow 1. Business Process Management
A Retail Process Welcome customer Offer Clothes Bill Clothes Hand over clothes
Different business processes • Production process • Support process • Managerial process
What is a Business Process? Organization Chart: units with assigned tasks Business Process: execution of tasks coordination between tasks Activity: elementary part of a working step Organization Chart WU Wien
Definitions related to Business Process • “A process is a completely closed, timely and logical sequence of activities which are required to work on a business object” (e. g. invoice). • “A business process is a special process that is directed by the business objectives of a company and by its business environment. ” (Becker, Kahn 2003). • “The real structure of the operation is that of a river. It continuously creates and distributes new products and services based on the same tasks or on tasks which only vary in detail. ” (Nordsieck 1972). • “The truth of Being and Nothing is accordingly the unity of the two: and this unity is BECOMING” (Hegel: Phänomenologie des Geistes, 1807) • “Panta rhei - Everything flows, nothing stands still. ” (Heraklitus of Ephesos, 535 - 475 BC)
Business Process versus Case • Business Process • Case (Process Instance) • Activity • Instance Activity • Business Process Attributes • Case Attributes Car Assembly Process Car Assembly Case 3324 Mount doors on 3324 Car body number, (Buyer), Car color Car body number 3324, Buyer Henry Ford, Car color white
Business Process Management • Task efficiency “It follows that the most important object of both the workmen and the management should be the training and development of each individual in the establishment, so that he can do (at his fastest pace and with the maximum of efficiency) the highest class of work for which his natural abilities fit him. ” (Frederick W. Taylor 1911) • Coordination efficiency “The question in view of this overall thinking is how to divide the tasks of a company other than by natural technical process phases? ” (Nordsieck 1972)
BPM Lifecycle v. d. Aalst, t. Hofstede, Weske 2003
BPM and Workflow 2. Business Process Modeling
Why Modeling?
What is Modeling? • “A model is a simplifying mapping of reality to serve a specific purpose” (Stachowiak: Allgemeine Modelltheorie, 1973) • Mapping: representation of natural or artificial originals that can be models themselves • Simplying: only those attributes of the original that are considered relevant (abstraction) • Pragmatics: model is used by modeler in place of original for a certain time and a certain purpose
Guidelines of Modeling (Go. M) 1. Correctness: relates to the mapping, capture attributes of the original correctly 2. Relevance: abstract from those aspects that are not relevant 3. Economic Efficiency: Keep an eye on the purpose of modeling task 4. Clarity: the model should be intuitive to understand for involved stakeholders 5. Comparability: Use a similar mapping for similar aspects 6. Systematic Design: define interfaces to related models Schütte, Rotthowe: The Guidelines of Modeling - An Approach to Enhance the Quality in Information Models, 1998.
Purposes of Business Process Modeling: Organization Design • Process Documentation • Process Reorganization • Process Monitoring and Controlling • Continuous Improvement • Quality Management: ISO 9000 • Benchmarking: Compare with best practice • Knowledge Management:
Purposes of Business Process Modeling: Information Systems Design • Selection of ERP software • Model based Customizing • Software Development • Workflow Management • Simulation
What to model of a business process • Tasks • Coordination between tasks • synchronization • decisions • parallel work • repetition • … • Organizational responsibilities • Required resources • Information input and output • …
Modeling method, technique, and language Karagiannis, Kühn 2002: Metamodelling Platforms. http: //www. dke. univie. ac. at/mmp/Full. Version_MMP_Dexa. ECWeb 2002. pdf
Business Process Modeling Languages Event-driven Process Chains (EPC) Petri Nets Business Process Modeling Notation (BPMN) UML Activity Diagrams
Business Process Modelling Tools 2004 Gartner: Magic Quadrant for Business Process Analysis, 2004, 04 March 2004 (http: //mediaproducts. gartner. com/reprints/idsscheer/119964. html)
The BPM Life cycle
BPM and Workflow 3. Event-driven Process Chains (EPC)
Example from the SAP Reference Model
EPC Semantics: prose version • Functions: activities of the business process • Events: pre- and post-conditions of functions • AND split: activates all subsequent branches in concurrency • OR split: triggers one, two or up to all of multiple subsequent branches. • XOR split: defines a choice to activate one of multiple subsequent branches. • AND join: waits for all incoming branches to complete. • OR join: waits for all active branches to complete. • XOR join: continue when one of alternative branches has completed. EPC Function Activity EPC Event Pre- & Postcondition XOR Join XOR Split AND Join AND Split OR Join OR Split
Exercise • Have a look at the EPC business process model below. Write down the information that is represented by this model in English language sentences. Be precise and detailed, but not dissipated. Use this little exercise for a brief explanation in how far modeling is efficient.
Exercise • Wenn der Filialbestand unter die Bestellmenge fällt, wird automatisch eine Bestellung generiert. Diese wird gegen den Zentralbestand geprüft. Falls dieser nicht ausreicht, werden Artikel nachbestellt. Wenn diese eingetroffen sind oder falls der Bestand von vornherein ausreicht, werden die Artikel ausgeliefert. Somit ist die Bestellung abgeschlossen.
Solution
Combine Views with extended EPCs (e. EPC)
Exercise • Die automatische Bestellgenerierung erfolgt auf Seiten der Filiale. Die erzeugte Bestellung geht in das Warenwirtschaftssystem ein, anhand dessen die Zentrale Disposition den Zentralbestand prüft. Die Zentrale Disposition führt auch eine eventuelle Nachbestellung aus, die zu einer Bereitstellung der Waren führt. Der Transport ist für die Auslieferung der Waren zuständig, die ebenfalls im Warenwirtschaftssystem erfasst wird.
Solution
BPM and Workflow 4. Semantic Issues
EPC Semantics: Transition Relation Cuntz, Kindler, 2004
EPC Semantics: Transition Relation II Non-local semantics
How EPCs work
How EPCs work II
How EPCs work III • Only if nothing can be propagated to arc a 21, c 1 is allowed to proceed. • But if c 1 is allowed to proceed, a folder can be propated to a 21. • But if something can be propagated to a 21, c 1 may not proceed. • If c 1 may not proceed, nothing can be propagated to arc a 21 (see 1. ) • …
Which one can fire?
Exercise • Bei einer Ausschreibung werden zuerst die verschiedenen Einreichungen geprüft. Falls kein Angebot den Erwartungen entspricht, wird geprüft, ob die Ausschreibung zurückgestellt werden kann. Falls nein erfolgt eine neue Ausschreibung. Falls ja wird die Ausschreibung auf Wiedervorlage gestellt. Falls mindestens ein Angebot den Erwartungen entspricht, wird das beste Angebot ausgewählt. Wenn sowohl das Angebot ausgewählt ist als auch die Ausschreibung auf Wiedervorlage gelegt wurde, wird ein Abschlussbericht erstellt.
Solution
Problems with Connector Mismatch
Problems with Connector Mismatch
Lessons Learned Use structured blocks Use simple loops
BPM and Workflow 5. EPC Reference Models
Real World EPC Process Models • SAP Reference Model Keller & Teufel: SAP R/3 Process-oriented Implementation, 1998. • Handels-H-Modell Becker & Schütte: Handelsinformationssysteme, 2 nd Edition, 2006. • Y-CIM-Modell für die Produktion Scheer: Wirtschaftsinformatik – Referenzmodelle für industrielle Geschäftsprozesse, 7 th Edition, 1997. • ARIS Platform 7. 0 by IDS Scheer AG: http: //www. ids-scheer. de/
The SAP Reference Model • About 10, 000 information models • 5 Hierarchy Levels • 29 Branches • Various model types: data, organization, processes, etc. • 604 EPC business process models
Reusing Reference Models Change EPC Models Change SAP System
Why Correct EPC Models? • Misunderstandings in • Teaching Processes • Comparing System with existing processes • Customization of System
How to find errors? • Soundness (v. d. Aalst 1997): • For every state that is reachable from the start, the end can be reached. • If the end is reached, there is no activity still active. • All activities can be reached. • Relaxed Soundness (Dehnert, Rittgens 2001): • Every activity participates in a run from start to end.
Verification Approach
An EPC from the SAP Reference Model
Mapping to YAWL
The resulting YAWL net
Petri Net analysis within Wof. YAWL
Potential Correction
Results
Modeling Error 1: Deadlock
Modeling Error 2: Livelock
Modeling Error 3: Multiple Instantiation
Why Errors • Hypotheses: • Model Size • Model Complexity • Error Patterns • Independent variables: • Number of each element type • Cycles • Complexity metrics based on state space • Logistic Regression: • Explain error (yes/no) • Nagelkerke R 2: 0. 30 and 0. 26 in significant models • Correct Classification: about 95%
Conclusion • Correctness is an issue in practice • Relaxed Soundness as a lower bound • At 5. 6% of the models with errors • Model Complexity matters • Closer coupling of process models and enterprise system needed
BPM and Workflow 6. Summary
ARIS House of Business Engineering Nüttgens, Scheer 2000
Lessons Learned Use structured blocks Use simple loops
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