Presentation given at the University of Sevilla on March 25, 2015. The subject is the hybrid process model, which is a cross-over of procedural and declarative modeling elements.

1. Hybrid Process Models
Prof.dr.ir. Hajo Reijers

4. D. Fahland, J. Mendling, H.A. Reijers, B. Weber, M. Weidlich, and S. Zugal. Declarative vs. Imperative Process Modeling Languages: The Issue
of Maintainability. In S. Rinderle-Ma, S. Sadiq, and F. Leymann, editors, Proceedings of the BPM workshops 2009, Lecture Notes in Business
Information Processing 43, 477-488. Springer Verlag, Berlin, 2010.
B. Weber, H.A. Reijers, S. Zugal, and W. Wild. The Declarative Approach to Business Process Execution: An Empirical Test.
In P. van Eck, J. Gordijn, and R. Wieringa, editors. Proceedings of the 21st International Conference on Advanced Information Systems
(CAiSE 2009), Lecture Notes in Computer Science 5565, 470-485. Springer-Verlag, Berlin, 2009.
D. Fahland, D. Lübke, J. Mendling, H.A. Reijers, B. Weber, M. Weidlich, and S. Zugal. Declarative versus Imperative
Process Modeling Languages: The Issue of Understandability. In T. Halpin, J. Krogstie, S. Nurcan, E. Proper, R. Schmidt, P. Soffer, and
R. Ukor, editors, Proceedings of the 14th International Workshop on ExploringModeling Methods in Systems Analysis and Design 2009
(EMMSAD 2009), Lecture Notes in Business Information Processing 29, 353-366, 2009.

5. Imperative Process Models

6. Imperative Process Models
• Flow-oriented
• Well-suited to rigid processes
• In a model with no flow, nothing can happen
• Adding flow allows for additional possible
behaviors
• Common in academia and industry

7. Declarative Process Models

8. Declarative Process Models
• Constraint-oriented
• Well-suited to flexible processes
• In an unconstrained model, anything can
happen
• Adding constraints limits behavior
• Still a novelty in industry

9. Industry test
• Ten professionals: Five consultants & five developers, average experience in
BPM: >11 years, average #models read in last 12 months: 15
• Rather easy to learn
• The more experienced, the more optimistic regarding usefulness
H.A. Reijers, T. Slaats, and C. Stahl. Declarative Modeling - An Academic Dream or the Future for BPM? In F. Daniel, J. Wang, and B. Weber,
editors, Proceedings of the 11th International Conference on Business Process Management (BPM 2013), Lecture Notes in Computer Science
8094, 307-322, 2013.

10. Hybrid Process Models

11. Hybrid Process Models
• Different parts of the same process may
be more or less flexible.
• Modeling a flexible process imperatively,
or a strict process declaratively, may
lead to incomprehensible models.
• Full-blown mixing of imperative and declarative paradigms:
– Petri nets + Declare [Westergaard et al.]
• Mixing of paradigms on the sub-process level:
– Pockets of flexibility in workflow services [Sadiq et al.]
– Flexibility as a Service (FAAS) [Aalst et al.]

12. Hybrid Process Models

13. Production
side
Consumption
side

14. Automated discovery
(process mining)
Human modeling
Production side

15. Define
groups
Define
blocks
Define
relations
between
blocks
Define
relations
between
activities
Vivian Hermans
Human modeling
V. Hermans. A hybrid process modeling approach. Master Thesis Report, 76 pages, TU Eindhoven, 2014.

17. Human modeling
• Partial evaluation of the approach
• Deciding which process part is to be modeled
declaratively or impretatively is surprisingly
simple
• Overall perception is that the approach is
useful, but not so easy to use

18. Automated Discovery
Event
Log
Process Model
Fabrizio Maggi
Tijs Slaats
F.M. Maggi, T. Slaats, and H.A. Reijers. The Automated Discovery of Hybrid Processes. In S. Sadiq, P. Soffer, H. Völzer, editors, Proceedings of the
12th International Conference on Business Process Management (BPM 2014), Lecture Notes in Computer Science 8659, 392-399, 2014.

19. Automated Discovery
Context
analysis
Clustering
(based on
context analysis)
Clustering
(association rule
mining)
Standard
Process
Discovery
Declare
Discovery
String Edit
Distance

20. Results of Imperative Miners
http://dx.doi.org/10.4121/uuid:3926db30-f712-4394-aebc-75976070e91f

21. Result of Hybrid Miner

22. Open issues
• How to guide human developers to create
hybrid process models?
• How to deal with some technical issues, e.g.
distinguishing parallellism from variation?
• How to properly evaluate the value of a
modeling notation?

23. Questions?
www.reijers.com
@profBPM