Bounded Model Checking for Timed Systems

Abstract

Abstract. Enormous progress has been achieved in the last decade in the verification of timed systems, making it possible to analyze significant real-world protocols. An open challenge is the identification of fully symbolic verification techniques, able to deal effectively with the finite state component as well as with the timing aspects. In this paper we propose a new, symbolic verification technique that extends the Bounded Model Checking (BMC) approach for the verification of timed systems. The approach is based on the following ingredients. First, a BMC problem for timed systems is reduced to the satisfiability of a math-formula, i.e., a boolean combination of propositional variables and linear mathematical relations over real variables (used to represent clocks). Then, an appropriate solver, called MathSAT, is used to check the satisfiability of the math-formula. The solver is based on the integration of SAT techniques with some specialized decision procedures for linear mathematical constraints, and requires polynomial memory. Our methods allow for handling expressive properties in a fully-symbolic way. A preliminary experimental evaluation confirms the potential of the approach.

Beyond Lassos: Complete SMT-Based Bounded Model Checking for Timed Automata

“…This section introduces BMC for finite runs and lasso-shaped infinite runs of timed (Büchi) automata. The lasso-based BMC for TAs is very similar to BMC for untimed systems and has been previously described in [9,10]. Lasso-based BMC is complete for untimed finite state systems but, as will be shown, despite a previous claim not complete for TAs.…”

“…However, in practice (and also in the experimental part of the paper) one usually defines a network of timed automata that can also have (shared and local) finite domain non-clock variables manipulated on the edges. The symbolic bounded model checking encodings presented later in the paper can be extended to handle both of these features, see, e.g., [9,10] for how to handle synchronization in a network of timed automata. Similarly, we do not define any property description language in the theoretical part but consider the reachability problem for timed automata and the non-emptiness problem for timed automata extended with Büchi acceptance conditions (like in [1]).…”

Symmetries in Modal Logics

“…Since then, many articles discuss how to detect and exploit syntactic symmetries in SAT solving [7,5,8,9,10,11,12,13,14]. Symmetries have been also extensively investigated and successfully exploited in other domains besides SAT like Constraint Satisfaction Problem [15,16], Integer Programming [17,18], Planning [19,20], Model Checking [21,22,23,24], Quantified Boolean Formulas (QBF) [25,26,27], and Satisfiability Modulo Theories (SMT) [28,29,30].…”

Innovative Rover Operations Concepts - Autonomous Planner (IRONCAP) - Supporting Rover Operations Planning on Ground

“…For model and plan validation and verification is based on symbolic model checking techniques exploiting Satisfiability Modulo Theory (Audemard, Cimatti, Kornilowicz, Sebastiani 2002), (Bozzano et al 2005a), (Bozzano et al 2005b), (Bruttomesso 2008), ) and abstraction refinement (Clarke, Kurshan, Veith 2010), (Clarke 2003). As described previously we have formulated 4 types of plan definition (A1-A4) which cover the three autonomy levels (E2-E4) covered within this study project.…”