Decidability and complexity of checking simulation preorder between data-aware web services


This paper addresses the problem of analysing specifications of data-centric Web service interaction protocols (also called artefactcentric business business level protocols). Specifications of such protocols includes data in addition to operation signatures and messages ordering constraints. Reasoning about data-aware service interactions is a complex task because of the inherently infinite states of underlying service execution instances. Our work focuses on characterising the problem of checking a refinement relation between service interaction protocol specifications. More specifically, we consider the problem of checking the simulation preorder [43] when service business protocols are represented using data-aware state machines, namely, the Colombo model [14]. In this framework, a service (i)exchanges messages using variables; (ii) act on a shared database; (iii) has a transition based behavior. We show that both simulation and state reachability properties are undecidable in this model. Furthermore, these properties are also undecidable when services do not communicate, and only read from the database. We show also that simulation is decidable when the maximum number of tuple in any instance of database is bounded (denoted DB-bounded service). Although DB-bounded services are also infinite-state systems, a finite symbolic representation of such services can be obtained by partitioning the original infinite state space into a finite number of equivalence classes. Then, a simulation algorithm can be designed using a symbolic procedure that manipulates (finite) sets of states (i.e., the equivalence classes) instead of (infinite) individual states.

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@inproceedings{Akroun2014DecidabilityAC, title={Decidability and complexity of checking simulation preorder between data-aware web services}, author={Lakhdar Akroun and Boualem Benatallah and Lhouari Nourine and Farouk Toumani}, year={2014} }