Formal Modeling and SMT-Based Parameterized Verification of Data-Aware BPMN

Abstract

We propose DAB -a data-aware extension of BPMN where the process operates over case and persistent data (partitioned into a read-only database called catalog and a read-write database called repository). The model trades off between expressiveness and the possibility of supporting parameterized verification of safety properties on top of it. Specifically, taking inspiration from the literature on verification of artifact systems, we study verification problems where safety properties are checked irrespectively of the content of the read-only catalog, and accepting the potential presence of unboundedly many tuples in the catalog and repository. We tackle such problems using an array-based backward reachability procedure fully implemented in MCMT -a state-of-the-art arraybased SMT model checker. Notably, we prove that the procedure is sound and complete for checking safety of DABs, and single out additional conditions that guarantee its termination and, in turn, show decidability of checking safety.

SMT-based verification of data-aware processes: a model-theoretic approach

“…The presented techniques have been implemented on top of the well-established MCMT model checker, making our approach fully operational. Notably, the machinery presented in this paper has been already employed to formalize and verify a data-aware extension of the de-facto process modeling standard BPMN (Calvanese et al 2019a), starting a line of research that aims at transferring our technical results into practical, end user-oriented settings.…”

“…As for experiments, we aim at building on the encouraging results reported here toward an extensive experimental evaluation of our approach, using the benchmark of Li et al (2017) and the concrete specification language in Calvanese et al (2019a) as a starting point. A natural next step is then to study how the computation of over-approximations, abstractions, and invariants (a capability that MCMT already supports but that should be adapted to the "db_driven" mode) and well-established techniques for SMT-based model checking like CEGAR (Alberti et al 2014a;McMillan 2006) and IC3 (Bradley 2011(Bradley , 2012Hoder and Bjørner 2012) can be used to speed up the verification of artifact systems.…”

“…which is a strongly local formula. The interested reader can find additional details about applications of (strongly) local RASs to data-aware business processes in Calvanese et al (2019a). Specifically, this paper contains a running example (verified against several properties) that can be represented using a RAS that is strongly local.…”

Model Completeness, Uniform Interpolants and Superposition Calculus

“…The usefulness of covers in model checking was already stressed in [37] and further motivated by our recent line of research on the verification of data-aware processes (also called 'database driven applications' in this paper) [12,13,15,17]. Notably, this is also operationally mirrored in the MCMT model checker [32] starting from version 2.8 (database driven module).…”

“…We consider the present work, together with [12,13,17,28], as the starting point for a full line of research dedicated to SMT-based techniques for the effective verification of data-aware processes [15], addressing richer forms of verification beyond safety (such as liveness, fairness, or full LTL-FO) and richer classes of artifact systems, (e.g., with concrete data types and arithmetics), while identifying novel decidable classes (e.g., by restricting the structure of the DB and of transition and state formulae) beyond the ones presented in [13,17]. Concerning implementation, we plan to further develop our tool to incorporate in it the plethora of optimizations and sophisticated search strategies available in infinite-state SMT-based model checking.…”