Hybrid Models Prof.dr.ir. Hajo Reijers

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.

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

Declarative versus Imperative

Example

Imperative Process Models

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

Declarative Process Models

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

Reliability Maintainability

Reusability

Usability

Por tability Efficiency

Functionality

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)

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

Example

Sequential Change Requirement: Add activity after D

Cirumstantial Change Requirement: Guarantee that A and D are exclusive

good fit

bad fit

a) Circumstantial Change Task b) Sequential Change Task

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

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

Outcomes sometimes valuable, but often inconclusive…

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.

Hybrid Process Models

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.]

Production side

Consumption side

Automated discovery (process mining)

Human modeling

Production side

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

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.

Automated Discovery

Context analysis

Clustering (based on

context analysis)

Clustering (association rule

mining)

Standard Process

Discovery

Declare Discovery

String Edit Distance

Results of Imperative Miners

http://dx.doi.org/10.4121/uuid:3926db30-f712-4394-aebc-75976070e91f

Result of Hybrid Miner

Hybrid models that mix declarative and

imperative elements seem promising

Are there wider opportunities for modeling

techniques?

BPMN

DMN PBD

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

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

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

Questions?

www.reijers.com @profBPM

Marcel Duchamp, Roue de bicyclette (Bicycle Wheel), 1960. Moderna Museet, Stockholm