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International audienceThe first step in the evaluation of vehicular ad hoc networks (VANETs) applications is based on simulations. The quality of those simulations not only depends on the accuracy of the network model but also on the degree of reality of the underlying mobility model. VehILux-a recently proposed vehicular mobility model, allows generating realistic mobility traces using traffic volume count data. It is based on the concept of probabilistic attraction points. However, this model does not address the question of how to select the best values of the probabilities associated with the points. Moreover, these values depend on the problem instance (i.e. geographical region). In this article we demonstrate how genetic algorithms (GAs) can be used to discover these probabilities. Our approach combined together with VehILux and a traffic simulator allows to generate realistic vehicular mobility traces for any region, for which traffic volume counts are available. The process of the discovery of the probabilities is represented as an optimisation problem. Three GAs-generational GA, steady-state GA, and cellular GA-are compared. Computational experiments demonstrate that using basic evolutionary heuristics for optimising VehILux parameters on a given problem instance permits to improve the model realism. However, in some cases, the results significantly deviate from real traffic count data. This is due to the route generation method of the VehILux model, which does not take into account specific behaviour of drivers in rush hours

Noninterference is a property that captures confidentiality of actions executed by a given process. However, the property is hard to guarantee in realistic scenarios. We show that the security of a system can be seen as an interplay between functionality requirements and the strategies adopted by users, and based on it we propose a weaker notion of noninterference which we call strategic noninterference. We also give a characterization of strategic noninterference through unwinding relations for specific subclasses of goals and for the simplified setting where a strategy is given as a parameter.

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We present a game-theoretic approach to coercion-resistance from the point of view of an honest election authority that chooses between various protection methods with different levels of resistance and different implementation costs. We give a simple game model of the election and propose a preliminary analysis. It turns out that, in the games that we look at, Stackelberg equilibrium for the society does not coincide with maxmin, and it is always more attractive to the society than Nash equilibrium. This suggests that the society is better off if the security policy is publicly announced, and the authorities commit to it. 3 The definition was game-based in the technical sense, i.e., the security property was defined as the outcome of an abstract game between the "verifier" and the "adversary". In this paper, we use game models to study the interaction between the actual participants of the protocol.