Soundness of Timed-Arc Workflow Nets in Discrete and Continuous-Time Semantics

Analysis of workflow processes with quantitative aspectslike timing is of interest in numerous time-critical applications. We suggest a workflow model based on timed-arc Petri nets and studythe foundational problems of soundness and strong (time-bounded) soundness.We first consider the discrete-time semantics (integer delays)and explore the decidability of the soundness problemsand show, among others, that soundness is decidable for monotonic workflow nets while reachability is undecidable.For general timed-arc workflow nets soundness andstrong soundness become undecidable, though we can design efficientverification algorithms for the subclass of bounded nets. We also discuss the soundness problem in the continuous-timesemantics (real-number delays) and show that for nets withnonstrict guards (where the reachability question coincides for bothsemantics) the soundness checking problem does not in generalfollow the approach for the discrete semantics and different zone-basedtechniques are needed for introducing its decidability in the bounded case.Finally, we demonstrate the usability of our theory onthe case studies of a Brake System Control Unit used in aircraft certification, the MPEG2 encoding algorithm, and a blood transfusion workflow.The implementation of the algorithms is freely available as a part of the model checker TAPAAL (www.tapaal.net).

[1]  Ferucio Laurentiu Tiplea,et al.  Soundness for S - and A -Timed Workflow Nets Is Undecidable , 2009, IEEE Trans. Syst. Man Cybern. Part A.

[2]  Ferucio Laurentiu Tiplea,et al.  Timed workflow nets , 2005, Seventh International Symposium on Symbolic and Numeric Algorithms for Scientific Computing (SYNASC'05).

[3]  Hans-Michael Hanisch.  Analysis of Place/Transition Nets with Timed Arcs and its Application to Batch Process Control , 1993, Application and Theory of Petri Nets.

[4]  Jirí Srba,et al.  Verification of Liveness Properties on Closed Timed-Arc Petri Nets , 2012, MEMICS.

[5]  Tommaso Bolognesi,et al.  From timed Petri nets to timed LOTOS , 1990, PSTV.

[6]  Sea Ling,et al.  Time Petri nets for workflow modelling and analysis , 2000, Smc 2000 conference proceedings. 2000 ieee international conference on systems, man and cybernetics. 'cybernetics evolving to systems, humans, organizations, and their complex interactions' (cat. no.0.

[7]  Jirí Srba,et al.  Verification of Timed Healthcare Workflows Using Component Timed-Arc Petri Nets , 2012, FHIES.

[8]  Moe Thandar Wynn,et al.  Soundness of workflow nets: classification, decidability, and analysis , 2011, Formal Aspects of Computing.

[9]  Changjun Jiang,et al.  Towards a Workflow Model of Real-Time Cooperative Systems , 2003, ICFEM.

[10]  Jirí Srba,et al.  TAPAAL 2.0: Integrated Development Environment for Timed-Arc Petri Nets , 2012, TACAS.

[11]  Wil M. P. van der Aalst,et al.  Verification of Workflow Nets , 1997, ICATPN.

[12]  Amir Pnueli,et al.  On Discretization of Delays in Timed Automata and Digital Circuits , 1998, CONCUR.

[13]  L. Dickson.  Finiteness of the Odd Perfect and Primitive Abundant Numbers with n Distinct Prime Factors , 1913 .

[14]  Thomas Freytag,et al.  Visualizing the Soundness of Workflow Nets , 2006 .

[15]  Alan J. Hoffman,et al.  Integral Boundary Points of Convex Polyhedra , 2010, 50 Years of Integer Programming.

[16]  Christian Ellen,et al.  Sequence Diagram Test Case Specification and Virtual Integration Analysis using Timed-Arc Petri Nets , 2013, FESCA.

[17]  Jason Cong,et al.  Scheduling with soft constraints , 2009, 2009 IEEE/ACM International Conference on Computer-Aided Design - Digest of Technical Papers.

[18]  Wang Yi,et al.  Time-abstracted Bisimulation: Implicit Specifications and Decidability , 1997, Inf. Comput..

[19]  Wil M. P. van der Aalst,et al.  The Application of Petri Nets to Workflow Management , 1998, J. Circuits Syst. Comput..

[20]  Jirí Srba,et al.  Verification of Timed-Arc Petri Nets , 2011, SOFSEM.

[21]  David de Frutos-Escrig,et al.  On non-decidability of reachability for timed-arc Petri nets , 1999, PNPM.

[22]  Lasse Jacobsen,et al.  Undecidability of Coverability and Boundedness for Timed-Arc Petri Nets with Invariants , 2009, MEMICS.

[23]  Ferucio Laurentiu Tiplea,et al.  E-timed Workflow Nets , 2006, 2006 Eighth International Symposium on Symbolic and Numeric Algorithms for Scientific Computing.

[24]  George S. Avrunin,et al.  A benchmark for evaluating software engineering techniques for improving medical processes , 2010, SEHC '10.

[25]  Valentín Valero Ruiz,et al.  Applying timed-arc Petri nets to improve the performance of the MPEG-2 encoding algorithm , 2004, 10th International Multimedia Modelling Conference, 2004. Proceedings..