Compositional Parameter Synthesis

Abstract

We address the problem of parameter synthesis for parametric timed systems (PTS). The motivation comes from industrial configuration problems for production lines. Our method consists in compositionally generating over-approximations for the individual components of the input systems, which are translated, together with global properties, to ∃∀SMT problems. Our translation forms the basis for optimised and robust parameter synthesis for slightly richer models than PTS. Work supported by the European projects BEinCPPS, CPSE-labs and OpenMOS.

Learning-Based Compositional Parameter Synthesis for Event-Recording Automata

“…The recent work [9] is close to our goal, as it proposes an approach for compositional parameter synthesis, based on the derivation of interaction and component invariants. The method is implemented in a prototype in Scala, making use of IMITATOR [5].…”

“…We warmly thank Lȃcrȃmioara Aştefȃnoaei for her appreciated help with installing and using the prototype tool of [9].…”

“…The method is implemented in a prototype in Scala, making use of IMITATOR [5]. Whereas both [9] and our approach address reachability or safety properties, the class of PTAs of [9] is larger; conversely, we add no further restrictions on the models, whereas in [9] all clocks and (more problematically) parameters must be local to a single component and cannot be shared.…”

“…We were not able to perform a comparison with [9]; the prototype of [9] always failed to compute a result. In addition, our Fischer benchmark does not fit in [9] as Fischer makes use of shared parameters.…”

What’s decidable about parametric timed automata?

“…Despite undecidability (in general [AHV93]) or intractability (for L/U-PTAs [JLR15]), semi-algorithms or approximated procedures could be devised; SMT-based techniques [KP12], or the integer hull approximation [JLR15; ALR15] can serve as a basis for future works. Also note that two recent orthogonal works aimed at performing synthesis in a compositional manner [Aşt+16;AL17b]. Also, combining nonparametric analysis (e. g., with the efficient model checker Uppaal) with parametric analysis, so as to find perhaps not all valuations, but at least some of them, is certainly a promising direction of research.…”