Peter E. Bulychev

UPPAAL-SMC: Statistical Model Checking for Priced Timed Automata ∗

This paper offers a survey of UPPAAL-SMC, a major extension of the real-time verification tool UPPAAL. UPPAAL-SMC allows for the efficient analysis of performance properties of networks of priced timed automata under a natural stochastic semantics. In particular, U PPAAL-SMC relies on a series of extensions of the statistical model checking app roach generalized to handle real-time systems and estimate undecidable problems. UPPAAL-SMC comes together with a friendly user interface that allows a user to specify complex problems in an efficient manner as well as to get feedback in the form of probability distributions and compare probabilities to analyze performance aspects of systems. The focus of the survey is on the evolution of the tool ‐ including modeling and specification formalisms as well as techniques applied ‐ tog ether with applications of the tool to case studies.

Checking and distributing statistical model checking

In this paper we propose a general framework for distributed statistical model checking of networks of priced timed automata. The first contribution is a new algorithm to distribute sequential hypothesis testing without introducing bias in the results. The second contribution is an implementation of this algorithm in Uppaal. The major contribution is an experimental and analytical evaluation of the approach through case studies, including an analysis of the SMC algorithm itself.

Efficient on-the-fly Algorithm for Checking Alternating Timed Simulation

In this paper we focus on property-preserving preorders between timed game automata and their application to control of partially observable systems. We define timed weak alternating simulation as a preorder between timed game automata, which preserves controllability. We define the rules of building a symbolic turn-based two-player game such that the existence of a winning strategy is equivalent to the simulation being satisfied. We also propose an on-the-fly algorithm for solving this game. This simulation checking method can be applied to the case of non-alternating or strong simulations as well. We illustrate our algorithm by a case study and report on results.

Monitor-Based statistical model checking for weighted metric temporal logic

We present a novel approach and implementation for analysing weighted timed automata (WTA) with respect to the weighted metric temporal logic (WMTL≤). Based on a stochastic semantics of WTAs, we apply statistical model checking (SMC) to estimate and test probabilities of satisfaction with desired levels of confidence. Our approach consists in generation of deterministic monitors for formulas in WMTL≤, allowing for efficient SMC by run-time evaluation of a given formula. By necessity, the deterministic observers are in general approximate (over- or under-approximations), but are most often exact and experimentally tight. The technique is implemented in the new tool Casaal. that we seamlessly connect to Uppaal-smc. in a tool chain. We demonstrate the applicability of our technique and the efficiency of our implementation through a number of case-studies.

Anti-unification algorithms and their applications in program analysis

A term t is called a template of terms t1 and t2 iff t1=tη1 and t2=tη2, for some substitutions η1 and η2. A template t of t1 and t2 is called the most specific iff for any template t′ of t1 and t2 there exists a substitution ξ such that t=t′ξ. The anti-unification problem is that of computing the most specific template of two given terms. This problem is dual to the well-known unification problem, which is the computing of the most general instance of terms. Unification is used extensively in automatic theorem proving and logic programming. We believe that anti-unification algorithms may have wide applications in program analysis. In this paper we present an efficient algorithm for computing the most specific templates of terms represented by labelled directed acyclic graphs and estimate the complexity of the anti-unification problem. We also describe techniques for invariant generation and software clone detection based on the concepts of the most specific templates and anti-unification.

Computing Nash Equilibrium in Wireless Ad Hoc Networks: A Simulation-Based Approach

This paper studies the problem of computing Nash equilibrium in wireless networks modeled by Weighted Timed Automata. Such formalism comes together with a logic that can be used to describe complex features such as timed energy constraints. Our contribution is a method for solving this problem using Statistical Model Checking. The method has been implemented in UPPAAL model checker and has been applied to the analysis of Aloha CSMA/CD and IEEE 802.15.4 CSMA/CA protocols.

Efficient controller synthesis for a fragment of MTL 0

In this paper we offer an efficient controller synthesis algorithm for assume-guarantee specifications of the form

Game-theoretic simulation checking tool

\varphi _1 \wedge \varphi _2 \wedge \cdots \wedge \varphi _n \rightarrow \psi _1 \wedge \psi _2 \wedge \cdots \wedge \psi _m