Correctness Ensuring Process Configuration: An Approach Based on Partner Synthesis
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This document discusses configurable process models and correctness of process model configurations. It presents an approach to characterize the set of all correct configurations of a configurable process model based on partner synthesis. The document uses examples of blocking and hiding transitions in a process model to illustrate how to determine if a particular configuration is correct and discusses questions around determining the set of all correct configurations and automatically completing a partial configuration.
![Open nets and weak termination
Open net:
• Labeled Petri net without any
syntactical restrictions.
• Special label: τ
• Set of final markings, in this case
[p4].
Correctness notion:
• weak termination: it is always
possible to reach a final marking
(weaker than classical soundness)
PAGE 11](https://image.slidesharecdn.com/bpm2010-configuration-using-synthesis-100930105817-phpapp02/85/Correctness-Ensuring-Process-Configuration-An-Approach-Based-on-Partner-Synthesis-12-320.jpg)
![Composition of open nets
p11 p21 p11 p21
y t11 t12 x t21 x τ (t12,
t21)
p12 p12
p22 p22
τ t13 t14 z
= τ t13 τ (t14,
t22)
p13 t22 z p13
t15 z τ (t15,
t22)
p14 p23 p14 p23
Ω ={[p14]} Ω ={[p23]} Ω ={[p14,p23]}
PAGE 12](https://image.slidesharecdn.com/bpm2010-configuration-using-synthesis-100930105817-phpapp02/85/Correctness-Ensuring-Process-Configuration-An-Approach-Based-on-Partner-Synthesis-13-320.jpg)
![Controllability
• An open net is controllable if there exists another
open net such that their composition is weakly
terminating.
• An open net is called a partner of another open net if
their composition is weakly terminating.
• A controllable open net has at least one partner.
• There are efficient techniques to check controllability
and to synthesize partners.
[Karsten Wolf. Does My Service Have Partners?. T. Petri Nets and Other Models
of Concurrency 2: 152-171 (2009)]
• These are implemented in Wendy.
[Niels Lohmann, Daniela Weinberg. Wendy: A Tool to Synthesize Partners for
Services. Petri Nets 2010: 297-307.]
PAGE 13](https://image.slidesharecdn.com/bpm2010-configuration-using-synthesis-100930105817-phpapp02/85/Correctness-Ensuring-Process-Configuration-An-Approach-Based-on-Partner-Synthesis-14-320.jpg)
![Controllability
p11
y t11 t12 x
weakly
p14 p12
= terminating
τ t13 t14 z partner??
p13
Ω ={[p13]}
Idea:
good configuration = partner!
PAGE 14](https://image.slidesharecdn.com/bpm2010-configuration-using-synthesis-100930105817-phpapp02/85/Correctness-Ensuring-Process-Configuration-An-Approach-Based-on-Partner-Synthesis-15-320.jpg)
Correctness Ensuring Process Configuration: An Approach Based on Partner Synthesis
- 1. Correctness Ensuring Process Configuration: An Approach Based on Partner Synthesis Wil van der Aalst (TU/e, QUT) Niels Lohmann (U-Rostock, TU/e) Marcello La Rosa (QUT) Jingxin Xu (QUT)
- 2. The need for configurable process models: CoSeLoG project +/- 430 Dutch PAGE 1 municipalities
- 3. The need for configurable process models: Suncorp case End to end process has between 250-1000 process steps Product Sales Service Claims 500 Dev steps • 25+ steps • 50+ steps • 75+ steps • 100+ steps Sources: Guidewire reference models, GIO CISSS Project, CI US&S P4PI Project Home Motor 30 Commercial variations Liability CTP / WC PAGE 2
- 4. Two variants of the same process … PAGE 3
- 5. Variation points Configuration = limiting behavior ! Activate Hide/skip Block Blocking Hiding Blocking Action Activating PAGE 4
- 6. Correctness of configurations + = Configurable Model + Configuration = Configured model • Question 1: Is a particular configuration correct? • Question 2: Is there a correct configuration? • Question 3: How to characterize the set of all correct configurations? • Question 4: How to auto-complete a configuration? PAGE 5
- 7. Transition Flow Place XOR-split Can t3 be blocked? AND-split AND-join XOR-join Token pI pI t1 t2 t1 t2 p2 p3 p4 p2 p3 p4 t5 t6 t5 t6 t3 t4 t4 p6 p6 p5 t8 p5 t8 p7 p7 t7 t7 pO pO PAGE 6
- 8. Transition Flow Place XOR-split Block t1 and hide t3 ? AND-split AND-join XOR-join Token p1 p1 Prepare Prepare Prepare Travel Form t1 t2 Travel Form t2 Travel Form (Secretary) (Employee) (Employee p2 p2 Arrange p3 t3 travel p4 p3 τ p4 insurance t3 (Employee) p5 p5 Request for Check & Update t7 t4 Travel Form t5 τ Request for Check & Update change (Admin) (Employee) change t7 t4 Travel Form t5 τ (Admin) (Employee) p6 p6 Submit Travel Form Submit t6 Travel Form for Approval t6 for Approval (Employee) (Employee) p7 p7 Approve Reject Travel Form t8 Travel Form t9 Approve Reject (Admin) (Admin) Travel Form t8 Travel Form t9 (Admin) (Admin) p8 p8 PAGE 7
- 9. Transition Flow Place XOR-split Block t4 also? AND-split AND-join XOR-join Token p1 p1 Prepare Prepare Prepare Travel Form t1 t2 Travel Form t2 Travel F (Secretary) (Employee) (Emplo p2 p2 Arrange p3 t3 travel p4 p3 t3 τ p4 insurance (Employee) p5 p5 Request for Check & Update Request for change t7 t4 Travel Form t5 τ change t7 t5 τ (Admin) (Employee) (Admin) p6 p6 Submit Submit Travel Form Travel Form t6 for Approval t6 for Approval (Employee) (Employee) p7 p7 Approve Reject Approve Reject Travel Form t8 Travel Form t9 Travel Form t8 Travel Form t9 (Admin) (Admin) (Admin) (Admin) p8 p8 PAGE 8
- 10. Existing approaches • Most approaches only consider the syntactical issues or simply create the configured model and analyze it (i.e., trail and error). • Our earlier approach using a SAT solver is an exception to this rule, but is limited to free-choice WF-nets. W.M.P. van der Aalst, M. Dumas, F. Gottschalk, A.H.M. ter Hofstede, M. La Rosa, J. Mendling, Preserving Correctness During Business Process Model Configuration. In Formal Aspects of Computing (FACS). Vol. 22 No. 3-4, 2010. PAGE 9
- 11. New approach • Based on partner synthesis developed in the Rostock group. • Implemented in C-YAWL using Wendy. • Advantages: 1. No syntactical restrictions (i.e. beyond WF-nets and free-choice). 2. Complete characterization of all correct configurations at design time: the so-called configuration guideline. 3. Computation time is moved from configuration time to design time. PAGE 10
- 12. Open nets and weak termination Open net: • Labeled Petri net without any syntactical restrictions. • Special label: τ • Set of final markings, in this case [p4]. Correctness notion: • weak termination: it is always possible to reach a final marking (weaker than classical soundness) PAGE 11
- 13. Composition of open nets p11 p21 p11 p21 y t11 t12 x t21 x τ (t12, t21) p12 p12 p22 p22 τ t13 t14 z = τ t13 τ (t14, t22) p13 t22 z p13 t15 z τ (t15, t22) p14 p23 p14 p23 Ω ={[p14]} Ω ={[p23]} Ω ={[p14,p23]} PAGE 12
- 14. Controllability • An open net is controllable if there exists another open net such that their composition is weakly terminating. • An open net is called a partner of another open net if their composition is weakly terminating. • A controllable open net has at least one partner. • There are efficient techniques to check controllability and to synthesize partners. [Karsten Wolf. Does My Service Have Partners?. T. Petri Nets and Other Models of Concurrency 2: 152-171 (2009)] • These are implemented in Wendy. [Niels Lohmann, Daniela Weinberg. Wendy: A Tool to Synthesize Partners for Services. Petri Nets 2010: 297-307.] PAGE 13
- 15. Controllability p11 y t11 t12 x weakly p14 p12 = terminating τ t13 t14 z partner?? p13 Ω ={[p13]} Idea: good configuration = partner! PAGE 14
- 16. Configurable interface (allow by default) PAGE 15
- 17. Configurable interface (block by default) PAGE 16
- 18. Configuration guideline (allow by default) CG PAGE 17
- 19. Configurable interface (block by default) CG PAGE 18
- 20. Configuration guideline (allow by default) CG PAGE 19
- 21. Configuration guideline (allow by default) CG PAGE 20
- 22. Configuration guideline (allow by default) CG PAGE 21
- 23. Configuration guideline (allow by default) CG PAGE 22
- 24. Tool support • YAWL editor − Creating C-YAWL models − Configuring C-YAWL models − Verification and auto-completion (using SAT solver and/or Wendy) • YAWL engine Configuration model (.cml) • YAWL services Quaestio C-YAWL Editor C-YAWL model (.yawl) Configured YAWL Engine C-YAWL (.yawl) spec. (.yawl) Questionnaire Mapping Model (.qml) (.cmap) Process Mapper Process Configured Individualizer EPC Configurator C-EPC (.epml) (.epml) C-EPC model (.epml) Questionnaire Designer C-EPC Designer Process Merger PAGE 23
- 25. C-YAWL p1 Prepare Prepare Travel Form t1 t2 Travel Form (Secretary) (Employee) p2 Arrange p3 t3 travel p4 insurance (Employee) p5 Request for Check & Update change t7 t4 Travel Form t5 τ (Admin) (Employee) p6 Submit Travel Form t6 for Approval (Employee) p7 Approve Reject Travel Form t8 Travel Form t9 (Admin) (Admin) p8 PAGE 24
- 26. C-YAWL PAGE 25
- 27. Conclusion • New approach for ensuring the correctness of process configurations based on partner synthesis. • Advantages: 1. No syntactical restrictions (i.e. beyond WF-nets and free- choice). 2. Complete characterization of all correct configurations at design time: the so-called configuration guideline. 3. Computation time is moved from configuration time to design time. • Implemented in C-YAWL using Wendy. − Complete support for workflow configuration, verification, and enactment. − Autocomplete, domain knowledge, etc. PAGE 26
- 28. More information • www.processconfiguration.com (various references to configuration literature and a comprehensive toolset) • www.yawlfoundation.org (YAWL has been extended to support configuration, cf. C-YAWL) • service-technology.org (paper and tools - including Wendy - related to the analysis of services) • www.win.tue.nl/coselog (webpage of the CoSeLoG project) PAGE 27