Keynote for the BPMDS, EMMSAD and EM workshops at the CAiSE 2015 conference in Stockholm.

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

3. Observations
 Continuous introduction of new modeling
techniques:
 IDEF3, EPCs, UML Activity Diagrams, Workflow Nets, BPEL,
BPML, BPMN, YAWL, etc.
 Superiority claims:
 “BPMN provides a number of advantages to modeling
business processes over UML”
 “BPML is clearly the language of choice”
 “BPEL is built upon the right mathematical model”
 “Contemporary process modeling languages are
inappropriate for real conceptual process modeling”
etc.

6. You claim, but never
tested it
You claim, it was tested,
it sucks, and you stick to
it
You claim, it was tested,
it’s actually pretty okay,
and you stick to it

8. Declarative versus Imperative

9. Example

10. Imperative Process Models

11. 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

12. Declarative Process Models

13. 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

15. Reliability
Maintainability
Reusability
Usability
Portability
Efficiency
Functionality

17. Theory on information artifacts
• Cognitive Dimensions Framework (CDF)
– a “matched pair” between the notational
characteristics and a task gives the best
performance.
• Trade-off between notational characteristics
– Sequential information explains how input
conditions lead to a certain outcome
– Circumstantial information relates to the overall
conditions that produced that outcome.
Gilmore, D., Green, T.: Comprehension and recall of miniature programs. International
Journal of Man-Machine Studies 21(1), 31–48 (1984)
Green, T.: Conditional program statements and their comprehensibility to professional
programmers. Journal of Occupational Psychology 50, 93–109 (1977)

18. Cognitive Dimensions Framework
(CDF)
Cognitive Dimension Description
Abstraction Types and availability of abstraction mechanism
Hidden Dependencies Important links between entities not visible
Diffuseness Verbosity of language
Premature Commitment Constraints on the order of doing things
Viscosity Resistance to change
Closeness of Mapping Closeness of representations to domain
Consistency Similar semantics are presented in a similar syntax
Error-Proneness Notation invites mistakes
Hard Mental Operations High demand on cognitive resources
Progressive Evaluation Work-to-date can be checked at any time
Provisionality Degree of commitment to actions or marks
Role Expressiveness The purpose of a component is readily interred

19. Example
Sequential Change Requirement:
Add activity after D
Cirumstantial Change Requirement:
Guarantee that A and D are exclusive
good fit
bad fit

20. a) Circumstantial Change Task
b) Sequential Change Task

22. This was an example:
– Interesting type of difference between models
– Relevant quality attribute
– Theoretical & empirical approach

23. Instead of new modeling techniques, we could
use more of this type of research

24. Outcomes sometimes valuable, but often
inconclusive…

26. Insight 1: Technique does not matter
Declare DCR-graph
PAGE 26
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.

28. Hybrid Process Models

29. 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.]

30. Production
side
Consumption
side

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

33. 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

34. 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.

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

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

37. Result of Hybrid Miner

38. Hybrid models that mix declarative and
imperative elements seem promising

39. Are there wider opportunities for modeling
techniques?

40. BPMN
DMN
PBD

41. J. Dietz. The Atoms, Molecules and Fibers of Organziations. Data and Knowledge Engineering, 47(3), 2003.
DEMO
DEMO offers five related models of organization:
 The interaction model
 The process model
 The action model
 The fact model, and
 The interstriction model

42. J. Dietz. The Atoms, Molecules and Fibers of Organziations. Data and Knowledge Engineering, 47(3), 2003.

45. You claim but never
tested it
You claim, it was tested,
it sucks, and you stick to
it
You claim, it was tested,
it’s actually pretty okay,
and you stick to it

46. Questions?
www.reijers.com
@profBPM
Marcel Duchamp, Roue de bicyclette (Bicycle Wheel), 1960.
Moderna Museet, Stockholm