Compositional specification of timed systems

We present timed automata and timed Petri nets and argue that timed automata and their associated parallel composition operator are not well adapted for the compositional description of timed Petri nets. Timed automata with deadlines are presented. We present a compositional translation method from 1-safe timed Petri nets to this model. We also present basic ideas for a general compositional specification framewor

Relating time progress and deadlines in hybrid systems

Time progress conditions in hybrid systems are usually specified in terms of invariants, predicates characterizing states where time can continuously progress, or in terms of deadline conditions, predicates characterizing states where time progress immediately stops. These specifications are each other's duals. The aim of this work is the study of relationships between general time progress conditions and these generated by using state predicates. It is shown that using deadline conditions or invariants allows to characterize all practically interesting time progress conditions. The study is performed by using a Galois connection between the corresponding lattices. We provide conditions for the connection to be a homomorphism and apply the results to the compositional description of hybrid system

Compositional verification for component-based systems and application

We present a compositional method for the verification of component-based systems described in a subset of the BIP language encompassing multi-party interaction without data transfer. The method is based on the use of two kinds of invariants. Component invariants which are over-approximations of components' reachability sets. Interaction invariants which are constraints on the states of components involved in interactions. Interaction invariants are obtained by computing traps of finite-state abstractions of the verified system. The method is applied for deadlock verification in the D-Finder tool. D-finder is an interactive tool that takes as input BIP programs and applies proof strategies to eliminate potential deadlocks by computing increasingly stronger invariants. The experimental results on non-trivial examples allow either to prove deadlock-freedom or to identify very few deadlock configurations that can be analyzed by using state space exploration

The IF toolset

This paper presents an overview on the IF toolset which is an environment for modelling and validation of heterogeneous real-time systems. The toolset is built upon a rich formalism, the IF notation, allowing structured automata-based system representations. Moreover, the IF notation is expressive enough to support real-time primitives and extensions of high-level modelling languages such as SDL and UML by means of structure preserving mappings. The core part of the IF toolset consists of a syntactic transformation component and an open exploration platform. The syntactic transformation component provides language level access to IF descriptions and has been used to implement static analysis and optimisation techniques. The exploration platform gives access to the graph of possible executions. It has been connected to different state-of-the-art model-checking and test-case generation tools. A methodology for the use of the toolset is presented at hand of a case study concerning the Ariane-5 flight program for which both an SDL and a UML model have been validate

A framework for scheduler synthesis

We present a framework integrating specification and scheduler generation for real time systems. In a first step, the system, which can include arbitrarily designed tasks (cyclic or sporadic, with or without precedence constraints, any number of resources and CPUs) is specified as a timed Petri net. In a second step, our tool generates the most general non preemptive online scheduler for the specification, using a controller synthesis techniqu

Ensuring properties of interaction systems

We propose results ensuring properties of a component-based system from properties of its interaction model and of its components. We consider here deadlock-freedom and local progress of subsystems. This is done in the framework of interaction systems, a model for component based modelling described in [9]. An interaction system is the superposition of two models: a behavior model and an interaction model. The behavior model describes the behavior of individual components. The interaction model describes the way the components may interact by introducing connectors that relate actions from different components. We illustrate our concepts and results with examples. © Springer-Verlag Berlin Heidelberg 2007