Artur Męski

Model checking temporal properties of reaction systems

This paper defines a temporal logic for reaction systems (rsCTL). The logic is interpreted over the models for the context restricted reaction systems that generalise standard reaction systems by controlling context sequences. Moreover, a translation from the context restricted reaction systems into boolean functions is defined in order to be used for a symbolic model checking for rsCTL over these systems. The model checking for rsCTL is proved to be pspace-complete. The proposed approach to model checking was implemented and experimentally evaluated using four benchmarks.

Two approaches to bounded model checking for linear time logic with knowledge

The paper deals with symbolic approaches to bounded model checking (BMC) for Linear Time Temporal Logic extended with the epistemic component (LTLK), interpreted over Interleaved Interpreted Systems. Two translations of BMC for LTLK to SAT and to operations on BDDs are presented. The translations have been implemented, tested, and compared with each other as well as with another tool on several benchmarks for MAS. Our experimental results reveal advantages and disadvantages of SAT- versus BDD-based BMC for LTLK.

Modularity and Openness in Modeling Multi-Agent Systems.

We revisit the formalism of modular interpreted systems (MIS) which encourages modular and open modeling of synchronous multi-agent systems. The original formulation of MIS did not live entirely up to its promise. In this paper, we propose how to improve modularity and openness of MIS by changing the structure of interference functions. These relatively small changes allow for surprisingly high flexibility when modeling actual multi-agent systems. We demonstrate this on two well-known examples, namely the trains, tunnel and controller, and the dining cryptographers. Perhaps more importantly, we propose how the notions of multi-agency and openness, crucial for multi-agent systems, can be precisely defined based on their MIS representations.

Action Synthesis for Branching Time Logic: Theory and Applications

We introduce a parametric extension of Action-Restricted Computation Tree Logic. A symbolic fixed-point algorithm providing a solution to the exhaustive parameter synthesis problem is proposed. The parametric approach allows for an in-depth system analysis and synthesis of correct parameter values. The time complexity of the problem and of the algorithm is provided. The prototype tool SPATULA, implementing the algorithm, is applied to the analysis of three benchmarks: faulty Train-Gate-Controller, Petersons Mutual Exclusion Protocol, and a Generic Pipeline Processing network. The experimental results show efficiency and scalability of our approach in comparison with a naive solution to the problem.

SMT-Based Reachability Checking for Bounded Time Petri Nets

Time Petri nets by Merlin and Farber are a powerful modelling formalism. However, symbolic model checking methods for them consider in most cases the nets which are 1-safe, i.e., allow the places to contain at most one token. In our paper we present an approach which applies symbolic verification to testing reachability for time Petri nets without this restriction. We deal with the class of bounded nets restricted to disallow multiple enabledness of transitions, and present the method of reachability testing based on a translation into a satisfiability modulo theory (SMT).

Two Approaches to Bounded Model Checking for a Soft Real-Time Epistemic Computation Tree Logic

We tackle two symbolic approaches to bounded model checking (BMC) for an existential fragment of the soft real-time epistemic computation tree logic (RTECTLK) interpreted over interleaved interpreted systems. We describe a BDD-based BMC method for RTECTLK, and provide its experimental evaluation and comparison with a SAT-based BMC method. Moreover, we have attempted a comparison with MCMAS on several benchmarks.

Verification of Linear-Time Temporal Properties for Reaction Systems with Discrete Concentrations

Reaction systems are a formal model for computational processes inspired by the functioning of the living cell. This paper introduces reaction systems with discrete concentrations, which are an extension of reaction systems allowing for quantitative modelling. We demonstrate that although reaction systems with discrete concentrations are semantically equivalent to the original qualitative reaction systems, they provide much more succinct representations in terms of the number of entities being used. We define a variant of Linear Time Temporal Logic interpreted over models of reaction systems with discrete concentrations. We provide its suitable encoding in SMT, together with bounded model checking, and present experimental results demonstrating the scalability of the verification method for reaction systems with discrete concentrations.

Reaction Mining for Reaction Systems

Reaction systems are a formal model for specifying and analysing computational processes in which reactions operate on sets of entities (molecules), providing a framework for dealing with qualitative aspects of biochemical systems. This paper is concerned with reaction systems in which entities can have discrete concentrations and reactions operate on multisets of entities, providing a succinct framework for dealing with quantitative aspects of systems. This is facilitated by a dedicated linear-time temporal logic which allows one to express and verify a wide range of behavioural system properties.

Bounded Model Checking for Linear Time Temporal-Epistemic Logic

We present a novel approach to the verification of multi-agent systems using bounded model checking for specifications in LTLK, a linear time temporal-epistemic logic. The method is based on binary decision diagrams rather than the standard conversion to Boolean satisfiability. We apply the approach to two classes of interpreted systems: the standard, synchronous semantics and the interleaved semantics. We provide a symbolic algorithm for the verification of LTLK over models of multi-agent systems and evaluate its implementation against MCK, a competing model checker for knowledge. Our evaluation indicates that the interleaved semantics can often be preferable in the verification of LTLK.

BDD-based Bounded Model Checking for Temporal Properties of 1-Safe Petri Nets

In the paper we present a bounded model checking for 1-safe Petri nets and properties expressed in LTL and the universal fragment of CTL, based on binary decision diagrams. The presented experimental results show that we have obtained a technique which performs better in some of the considered cases, in comparison with the existing SAT-based implementation. The results are also compared with standard BDD-based symbolic method.