1. 1 Static Analysis of Business Artifact-centric Operational Models Presented by Cagdas Gerede Cagdas Gerede 1, Kamal Bhattacharya 2, Jianwen Su 1 1: University of California Santa Barbara 2: IBM T.J. Watson Research Center

2. 2 Typical Approaches for Business Process Modeling Characteristics: [Leymann99, Aalst-JCSC98, Jackson97,Morrison94]  Process-centric: Focus on control and coordination of tasks  Ignore the informational perspective or treat it only within the context of single activities  Case-driven and cases are logically independent Problems  Lack of flexibility [Wang,Kumar-BPM05], [Aalst et al-DKE05], …  Hard to deal with changes [Casati et al-ER96], [Aalst et al-CSSE00], [Weske et al-HICSS01], …  Integration efforts are hindered [Bhattacharya-07]

3. 3 Artifact-centric Business Process Modeling Developed by IBM Research [NigamCaswell-IBMSJ03], [Bhattacharya et al-BPM07], [Liu et al- CAiSE07]… Centered on Business Artifacts: data objects that capture key information pertinent to business context Focus on life-cycles of business artifacts Similarities with data flow diagramming [DeMarco78], flow- based programming [Morrison94 ] Applied in practice successfully Insurance, Manufacturing, Pharmaceutical Industries [Bhattacharya et al - IBMSJ05]

4. 4 Example: High Tech Restaurant Guest Check Artifacts Kitchen OrderReceiptCash Balance Pending Active Payment Completed Canceled Guest Check customerName tableNo paymentDate … data states

5. 5 Example: High Tech Restaurant Guest Check Artifacts Kitchen OrderReceiptCash Balance Open GCs Archived KOs Closed GCs Archived GCs Pending Receipts Archived Receipts Cash Balance Pending KOs Paid Receipts Disagreed Receipts Ready KOs Add ItemDeliver Prepare & Test Quality Create Guest Check

6. 6 Prepare Receipt Example: High Tech Restaurant Guest Check Artifacts Kitchen OrderReceiptCash Balance Open GCs Archived KOs Closed GCs Archived GCs Pending Receipts Archived Receipts Cash Balance Pending KOs Paid Receipts Disagreed Receipts Ready KOs Add ItemDeliver Prepare & Test Quality Create Guest Check GCKO Update Cash Balance Payment Recalculate Receipt RCCB

7. 7 Example: High Tech Restaurant Open GCs Add Item GC KO Deliver GC Archived KOs Prepare Receipt Closed GCs Archived GCs Pending Receipts GC RC GC Update Cash Balance Payment Recalculate Receipt RC Archived Receipts Cash Balance GC CB RC GC KO Prepare & Test Quality Pending KOs Create Guest Check Paid Receipts RC Disagreed Receipts RC GC Ready KOs KO

8. 8 Artifact-centric Properties Persistence:  An artifact should never be lost Location Uniqueness:  An artifact should appear in only one location Arrival:  Can an artifact arrive into a repository? Encounter Synchronization Dependence …

9. 9 Location Uniqueness: An artifact should appear only in one location Persistence: An artifact should never be lost Arrival: Can an artifact arrive into a repository? Revisit: life cycle properties Paid Receipts Disagreed Receipts Receipt Paid Receipts Disagreed Receipts or Open Guest Checks Archived Guest Checks Guest Check

10. 10 Related Work Emphasis on Data Design as well as Control Flow Design  Document Driven Workflow Systems [Wang,Kumar-BPM05]  Case Handling [ Aalst et al-DKE05]  Vortex [Hull et al-WACC99], [Fu et al-TACAS01]  INSYDE [King,McLeod-TOIS85], TAXIS[Mylopoulos et al- TODS80], … Constraints on Life-cycles of Objects  Object Migration [Su-TCS97]  Object Histories [Ginsburg,Tanaka-TODS86]  Object Constraint Language  …

11. 11 Remainder of the Talk Formalization of Artifact-centric Business Process Models  Artifacts  Tasks  Operational Models Analysis of Properties  Location Uniqueness  Persistence  Arrival Conclusions

12. 12 Artifact An artifact  attributes,  methods,  states Similar to object-oriented classes augmented with states  Typestate [StromYemini-TSE86]  Method schemas [Abiteboul et al–PODS90]  Method structures [Hull et al–FODO88]  UML OCL, Alloy [Jackson-TOSEM02] Pending Active Payment Completed Canceled Guest Check addOrder setCancelDate receiptRequest setPaymentDate addOrder(…) setPaymentDate(…) customerName tableNo paymentDate Receipt Order data references methods states Open GCs Create Guest Check GC

13. 13 Task A task describes the actions performed on artifacts  has a set of variables  has a guarded state machine Artifact creation Artifact check out / check in Read/Update artifact data via artifact methods Read from external environment R1.checkOut(order) read(approvedDate) order.setApproved (approvedDate) R2.checkIn(order) reset R1 Pending Orders R2 Live Orders Live Orders Approve KO KO

14. 14 Operational Model Operational Model O = (A, R, T)  A: set of artifact types  R: set of repositories  T: set of task types

15. 15 Semantics Configuration A configuration is derivable from another configuration if … Execution graph of an operational model and a root configuration is a Kripke structure

16. 16 Semantics Configuration is a set of artifacts, tasks, mapping from repositories to artifacts A configuration is derivable from another configuration if there is a task in the configuration that can make a transition Execution graph of an operational model and a root configuration is a Kripke structure, with initial state is root configuration, and two configurations are related if one is derivable from the other

17. 17 Summary of Results Formalism guarantees location uniqueness and persistence Arrival  Not decidable with new artifact creation  Decidable without artifact creation and finite functions

18. 18 Location Uniqueness, Persistence Formalism guarantees location uniqueness and persistence Location Uniqueness:  Artifact cannot be checked out by two tasks checked in two repositories duplicated Persistence  An artifact can not be deleted overwritten

19. 19 Checking Arrival Reachability on execution graph Open Guest Checks … Archived Guest Checks … CiCi … … C1C1 C2C2 C3C3 C4C4 … …… Example: Does a guest check arrive at the archived guest checks repository?

20. 20 Arrival is not decidable Theorem: It is not decidable to check if an artifact can arrive into a repository R for an operational model O and a root configuration of O. But …

21. 21 without Artifact Creation? Observation  Size of execution graph: Infinite Domains are infinite Tasks can read values from infinite domains Finite abstraction of infinite space  Define an equivalence relation among configurations (similar to region approach [Alur-99])

22. 22 Abstraction Example: - only constant appears in the specification is 10 - two scalar variables: cost, amount amount cost 11 5 12 5 13 5 14 5 … cost < 10 < amount 4545 Equivalence class: 11 5 4545 Abstraction

23. 23 Decidable Fragment Theorem: It is decidable to check if an artifact can arrive into a repository R for an operational model O without new artifact creation, and a root configuration of O.

24. 24 Conclusions Preliminary results on life cycle properties of business artifacts Many interesting questions:  More declarative model Automatic Towards Formal Analysis of Artifact-Centric Business Process Models [Bhattacharya et. al. BPM 2007]  A language for specifying artifact life-cycle properties Specification and Verification of Artifact Behaviors in Business Process Models [Gerede-07]  Multi-artifact interactions  Automated design and tools  Evolution of models (business rules)

25. 25 Questions and Comments Thanks