Radu Mateescu

CADP 2006: a toolbox for the construction and analysis of distributed processes

CADP(Construction and Analysis of Distributed Processes) [2,3] is a toolbox for specification, rapid prototyping, verification, testing, and performance evaluation of asynchronous systems (concurrent processes with message-passing communication). The developments of CADP during the last five years led to a new release named CADP 2006 “Edinburgh” (as a tribute to the achievements in concurrency theory of the Laboratory for Foundations of Computer Science) that supersedes the previous version CADP 2001.

CADP 2011: a toolbox for the construction and analysis of distributed processes

CADP (Construction and Analysis of Distributed Processes) is a comprehensive software toolbox that implements the results of concurrency theory. Started in the mid-1980s, CADP has been continuously developed by adding new tools and enhancing existing ones. Today, CADP benefits from a worldwide user community, both in academia and industry. This paper presents the latest release, CADP 2011, which is the result of a considerable development effort spanning the last five years. The paper first describes the theoretical principles and the modular architecture of CADP, which has inspired several other recent model checkers. The paper then reviews the main features of CADP 2011, including compilers for various formal specification languages, equivalence checkers, model checkers, compositional verification tools, performance evaluation tools, and parallel verification tools running on clusters and grids. Finally, the paper surveys some significant case studies.

Efficient on-the-fly model-checking for regular alternation-free mu-calculus

Model-checking is a successful technique for automatically verifying concurrent finite-state systems. When designing a model-checker, a good compromise must be made between the expressive power of the property description formalism, the complexity of the model-checking problem, and the user-friendliness of the interface. We present a temporal logic and an associated model-checking method that attempt to fulfill these criteria. The logic is an extension of the alternation-free µ-calculus with ACTL-like action formulas and PDL-like regular expressions, allowing a concise and intuitive description of safety, liveness, and fairness properties over labeled transition systems. The model-checking method is based upon a succinct translation of the verification problem into a boolean equation system, which is solved by means of an efficient local algorithm having a good average complexity. The algorithm also allows to generate full diagnostic information (examples and counterexamples) for temporal formulas. This method is at the heart of the EVALUATOR 3.0 model-checker that we implemented within the CADP toolbox using the generic OPEN/CAESAR environment for on-the-fly verification.

Parallel state space construction for model-checking

The verification of concurrent finite-state systems by model-checking often requires to generate (a large part of) the state space of the system under analysis. Because of the state explosion problem, this may be a resource-consuming operation, both in terms of memory and CPU time. In this paper, we aim at improving the performances of state space construction by using parallelization techniques. We present parallel algorithms for constructing state spaces (or Labeled Transition Systems) on a network or a cluster of workstations. Each node in the network builds a part of the state space, all parts being merged to form the whole state space upon termination of the parallel computation. These algorithms have been implemented with the CADP verification tool set and experimented on various concurrent applications specified in LOTOS. The results obtained show close to ideal speedups and a good load balancing between network nodes.

A Model Checking Language for Concurrent Value-Passing Systems

Modal μ-calculus is an expressive specification formalism for temporal properties of concurrent programs represented as Labeled Transition Systems ( Lts s). However, its practical use is hampered by the complexity of the formulas, which makes the specification task difficult and error-prone. In this paper, we propose Mcl (Model Checking Language), an enhancement of modal μ-calculus with high-level operators aimed at improving expressiveness and conciseness of formulas. The main Mcl ingredients are parameterized fixed points, action patterns extracting data values from Lts actions, modalities on transition sequences described using extended regular expressions and programming language constructs, and an infinite looping operator specifying fairness. We also present a method for on-the-fly model checking of Mcl formulas on finite Lts s, based on the local resolution of boolean equation systems, which has a linear-time complexity for alternation-free and fairness formulas. Mcl is supported by the Evaluator 4.0 model checker developed within the Cadp verification toolbox.

Temporal logic patterns for querying dynamic models of cellular interaction networks

MOTIVATION Models of the dynamics of cellular interaction networks have become increasingly larger in recent years. Formal verification based on model checking provides a powerful technology to keep up with this increase in scale and complexity. The application of modelchecking approaches is hampered, however, by the difficulty for nonexpert users to formulate appropriate questions in temporal logic. RESULTS In order to deal with this problem, we propose the use of patterns, that is, high-level query templates that capture recurring biological questions and can be automatically translated into temporal logic. The applicability of the developed set of patterns has been investigated by the analysis of an extended model of the network of global regulators controlling the carbon starvation response in Escherichia coli. AVAILABILITY GNA and the model of the carbon starvation response network are available at http://www-helix.inrialpes.fr/gna.

CADP 2010: a toolbox for the construction and analysis of distributed processes

Cadp (Construction and Analysis of Distributed Processes) is a comprehensive software toolbox that implements the results of concurrency theory. Started in the mid 80s, CADP has been continuously developed by adding new tools and enhancing existing ones. Today, CADP benefits from a worldwide user community, both in academia and industry. This paper presents the latest release CADP 2010, which is the result of a considerable development effort spanning the last four years. The paper first describes the theoretical principles and the modular architecture of CADP, which has inspired several other recent model checkers. The paper then reviews the main features of CADP 2010, including compilers for various formal specification languages, equivalence checkers, model checkers, performance evaluation tools, and parallel verification tools running on clusters and grids.

Model Checking for Managers

Model checking is traditionally applied to computer system design. It has proven to be a valuable technique. However, it requires detailed specifications of systems and requirements, and is therefore not very accessible. In this paper we show how model checking can be applied in the context of business modeling and analysis by people that are not trained in formal techniques. Spin is used as the model checker underlying a graphical modeling language, and requirements are specified using business requirements patterns, which are translated to LTL. We illustrate our approach using a business model of an insurance company.

Verification of Temporal Properties of Processes in a Setting with Data

We define a value-based modal µ-calculus, built from first-order formulas, modalities, and fixed point operators parameterized by data variables, which allows to express temporal properties involving data. We interpret this logic over µCrl terms defined by linear process equations. The satisfaction of a temporal formula by a µCrl term is translated to the satisfaction of a first-order formula containing parameterized fixed point operators. We provide proof rules for these fixed point operators and show their applicability on various examples.

CAESAR_SOLVE: A generic library for on-the-fly resolution of alternation-free Boolean equation systems

Boolean equation systems (Bess) provide a useful framework for modeling various verification problems on finite-state concurrent systems, such as equivalence checking and model checking. These problems can be solved on the fly (i.e., without constructing explicitly the state space of the system under analysis) by using a demand-driven construction and resolution of the corresponding Bes. In this article, we present a generic software library dedicated to on-the-fly resolution of alternation-free Bess. Four resolution algorithms are currently provided by the library: algorithms A1 and A2 are general, the latter being optimized to produce small-depth diagnostics, whereas algorithms A3 and A4 are specialized for handling acyclic and disjunctive/conjunctive Bess in a memory-efficient way. The library has been developed within the Cadp verification toolbox using the generic Open/Caesar environment and is currently used for three purposes: on-the-fly equivalence checking modulo five widely used equivalence relations, on-the-fly model checking of regular alternation-free modal μ-calculus, and on-the-fly reduction of state spaces based on τ-confluence .