Abstract.A group of agents can be used to perform patrolling tasks in a variety of domains ranging from computer network administration to computer wargame simulations. Despite its wide range of potential applications, multiagent architectures for patrolling have not been studied in depth yet. First state of the art approaches used to deal with related problems cannot be easily adapted to the patrolling task specificity. Second, the existing patrollingspecific approaches are still in preliminary stages. In this paper, we present an original in-depth discussion of multi-agent patrolling task issues, as well as an empirical evaluation of possible solutions. In order to accomplish this study we have proposed different architectures of multi-agent systems, various evaluation criteria, two experimental scenarios, and we have implemented a patrolling simulator. The results show which kind of architecture can patrol an area more adequately according to the circumstances.

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Abstract. For some organizations, the proactive approach to product lines may be inadequate due to prohibitively high investment and risks. As an alternative, the extractive and the reactive approaches are incremental, offering moderate costs and risks, and therefore sometimes may be more appropriate. However, combining these two approaches demands a more detailed process at the implementation level. This paper presents a method and a tool for extracting a product line and evolving it, relying on a strategy that uses refactorings expressed in terms of simpler programming laws. The approach is evaluated with a case study in the domain of games for mobile devices, where variations are handled with aspect-oriented constructs.