Operating Guidelines for Petri Net Based Services Models
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This document discusses operating guidelines for service models based on Petri nets. It proposes that the operating guideline for a service should provide an implicit description of all possible partner services. It describes how to represent operating guidelines and annotate partner services using binary decision diagrams to determine if a partner satisfies the operating guideline. Nondeterministic partner services can be matched by constructing an annotated deterministic version.
![Example ?€ ?C ?T !B !B Vending machine !€ !C ?B Partner !€ !C ?B No partner 1 2 3 4 5 6 7 8 9 10 11 12 13 [1, 5 , - ] [2, 5 , € ] [2, 6 , - ] [3, 5 , €C ] [3, 7 , - ] [3, 6 , C ] [3, 9 , B ] [ 4 , 9 , - ] [10, 5 , - ] [ 11 , 5 , € ] [12, 5 , C ] [ 11 , 6 , - ]](https://image.slidesharecdn.com/pn2006tutorialb-090914062715-phpapp01/85/Operating-Guidelines-for-Petri-Net-Based-Services-Models-5-320.jpg)
Operating Guidelines for Petri Net Based Services Models
- 1. Operating Guidelines for Petri Net Based Service Models Karsten Wolf (= Karsten Schmidt) Universität Rostock Open Workflow Nets
- 2. Service Oriented Architecture Service Provider Service Broker Service Requester publish find bind
- 3. Example Vending machine as automaton € C T B ?€ ?C ?T !B !B ?
- 4. Publish what? One proposal: (abstract version of) provided service We: Description of all partner requesters ?
- 5. Example ?€ ?C ?T !B !B Vending machine !€ !C ?B Partner !€ !C ?B No partner 1 2 3 4 5 6 7 8 9 10 11 12 13 [1, 5 , - ] [2, 5 , € ] [2, 6 , - ] [3, 5 , €C ] [3, 7 , - ] [3, 6 , C ] [3, 9 , B ] [ 4 , 9 , - ] [10, 5 , - ] [ 11 , 5 , € ] [12, 5 , C ] [ 11 , 6 , - ]
- 6. Operating guideline ...of a (provided) service P is: operational description of all partners of P
- 7. Operating guideline ?€ ?C ?T !B !B !€ !C ?B !€ !T ?B !T !€ ?B !C !€ ?B !€ !C ?B !T ?B .... !€ !€ !€ !T !T !C !C ?B ?B
- 8. Operating guideline !€ !C ?B !€ !T ?B !T !€ ?B !C !€ ?B !€ !C ?B !T ?B .... !€ !€ !€ !T !T !C !C ?B ?B Remember most permissive partner
- 9. Operating guideline !€ !C ?B !€ !T ?B !T !€ ?B !C !€ ?B !€ !C ?B !T ?B .... !€ !€ !€ !T !T !C !C ?B ?B !€ !€ !€ !T !T !C !C ?B ?B !T !€ !C !T !C
- 10. Operating guideline = Implicit description of all partners !€ !C ?B !€ !T ?B !T !€ ?B !C !€ ?B !€ !C ?B !T ?B .... !€ !€ !€ !T !T !C !C ?B ?B !€ !€ !€ !T !T !C !C ?B ?B !T !€ !C !T !C
- 11. Find how? Simple case: Requester is deterministic must be subgraph that satisfies the annotations Involved case: Requester is nondeterministic ?
- 12. Nondeterminism Multiple transitions with same label a : No problem – all a -successors must meet the requirements of the unique a -successor in operating guideline B) -transitions: Traced back to annotated deterministic automaton
- 13. Nondeterminism annotated Determinism !€ !C ?B !C !€ !T ?B !C !€ ( !T !C) ?B !C !€ !T ?B !C !€ !T ?B !€ !T ?B ?B !C !T ?B !C !€ !T ?B !C !€ !T ?B
- 14. Matching nondeterministic services with operating guideline Thm: (Nondeterministic partner) R is partner of P iff its constructed annotated version R* is a subgraph of OG P such that annotations of R* imply corresponding annotations of OG P !€ !€ !€ !T !T !C !C ?B ?B !T !€ !C !T !C 6 !€ !C ?B !C !€ !T ?B 0 1 5 !C !€ ( !T !C) ?B !C !€ !T ?B !C !€ !T ?B 6 !T ?B 5 !C !€ !T ?B !C !€ !T ?B
- 15. Service oriented architecture publish find bind ?€ ?C ?T !B !B !€ !€ !€ !T !T !C !C ?B ?B !T !€ !C !T !C !€ !€ !€ !T !T !C !C ?B ?B !T !€ !C !T !C !€ !T !C ?B ?B
- 16. Representation of operating guidelines with binary decision diagrams (BDD) Boolean function f Decision tree BDD 1 1 1 1 0 1 1 1 0 0 0 0 f b a
- 17. Operating guidelines as BDD BDD structure : Codes most permissive partner BDD annotation : Codes annotation !€ !€ !€ !C !C !T ?B ?B !T !€ !C !T !C !T !€ !€ ?B ?B true
- 18. BDD structure Code states !€ !€ !€ !C !C !T ?B ?B !T !€ !C !T !C !T !€ !€ ?B ?B true Code labels: Code for each edge 6 !€ !€ !€ !C !C !T ?B ?B !T !€ !C !T !C !T !€ !€ ?B ?B 0 2 1 3 5 4 true !T 1 5 101 5 110 … 001 000 6 … 1 0 11 10 01 00 ?B !T !€ !C 1 = 001 b 5 = 101 b 001 10 101 !T = 10 b
- 19. BDD structure f structure 6 !€ !€ !€ !C !C !T ?B ?B !T !€ !C !T !C !T !€ !€ ?B ?B 0 2 1 3 5 4 true
- 20. BDD Annotation Use code for states Annotations are boolean Functions 110 … 001 000 6 … 1 0 !€ !€ !€ !C !C !T ?B ?B !T !€ !C !T !C !T !€ !€ ?B ?B true 6 !€ !€ !€ !C !C !T ?B ?B !T !€ !C !T !C !T !€ !€ ?B ?B 0 2 1 3 5 4 true !€ !C !T 0
- 21. BDD Annotation 6 !€ !€ !€ !C !C !T ?B ?B !T !€ !C !T !C !T !€ !€ ?B ?B 0 2 1 3 5 4 true
- 22. !€ !€ !€ !C !C !T ?B ?B !T !€ !C !T !C !T !€ !€ ?B ?B true
- 23. Matching with BDDs Input: Operating guideline in BDD-representation, requester R (explicitely) – transform R into annotated deterministic R' – Transform R' into BDD-representation (take state coding from operating guideline – Check: BDD S BDD structure BDD L BDD annotation
- 24. Ongoing research Operating guidelines for services with cycles in behaviour Decentralized, autonomous partners Decide exchangeability