Abstract

International audience; The temporal evolution of mobile processes is governed by independently operating local clocks and their migration timeouts. We define a formalism modelling such distributed systems allowing (maximal) parallel execution at each location. Taking into account explicit timing constraints based on migration and interprocess communication, we introduce and study a number of timed behavioural equivalences, aiming to provide theoretical underpinnings of verification methods. We also investigate relationships between such behavioural equivalences. Document type: Part of book or chapter of book

Abstract

International audience We introduce a continuous time stochastic broadcast calculus for mobile and wireless networks. The mobility between nodes in a network is modeled by a stochastic mobility function which allows to change part of a network topology depending on an exponentially distributed delay and a network topology constraint. We allow continuous time stochastic behavior of processes running at network nodes, e.g. in order to be able to model randomized protocols. The introduction of group broadcast and an operator to help avoid flooding allows us to define a novel notion of broadcast abstraction. Finally, we define a weak bisimulation congruence and apply our theory on a leader election protocol. Document type: Part of book or chapter of book

Abstract

Many control systems have large, infinite state space that can not be easily abstracted. One method to analyse and verify these systems is reachability analysis. It is frequently used for air traffic control and power plants. Because of lack of complete information about the environment or unpredicted changes, the stochastic approach is a viable alternative. In this paper, different ways of introducing rechability under uncertainty are presented. A new concept of stochastic bisimulation is introduced and its connection with the reachability analysis is established. The work is mainly motivated by safety critical situations in air traffic control (like collision detection and avoidance) and formal tools are based on stochastic analysis.