Language Emptiness of Continuous-Time Parametric Timed Automata

Parametric timed automata extend the standard timed automata with the possibility to use parameters in the clock guards. In general, if the parameters are real-valued, the problem of language emptiness of such automata is undecidable even for various restricted subclasses. We thus focus on the case where parameters are assumed to be integer-valued, while the time still remains continuous. On the one hand, we show that the problem remains undecidable for parametric timed automata with three clocks and one parameter. On the other hand, for the case with arbitrary many clocks where only one of these clocks is compared with (an arbitrary number of) parameters, we show that the parametric language emptiness is decidable. The undecidability result tightens the bounds of a previous result which assumed six parameters, while the decidability result extends the existing approaches that deal with discrete-time semantics only. To the best of our knowledge, this is the first positive result in the case of continuous-time and unbounded integer parameters, except for the rather simple case of single-clock automata

Interrupt Timed Automata with Auxiliary Clocks and Parameters

International audienceInterrupt Timed Automata (ITA) are an expressive timed model, introduced to take into account interruptions according to levels. Due to this feature, this formalism is incomparable with Timed Automata. However several decidability results related to reachability and model checking have been obtained. We add auxiliary clocks to ITA, thereby extending its expressive power while preserving decidability of reachability. Moreover, we define a parametrized version of ITA, with polynomials of parameters appearing in guards and updates. While parametric reasoning is particularly relevant for timed models, it very often leads to undecidability results. We prove that various reachability problems, including robust reachability, are decidable for this model, and we give complexity upper bounds for a fixed or variable number of clocks, levels and parameters

Formal verification of mobile robot protocols

International audienceMobile robot networks emerged in the past few years as a promising distributed computing model. Existing work in the literature typically ensures the correctness of mobile robot protocols via ad hoc handwritten proofs, which, in the case of asynchronous execution models, are both cumbersome and error-prone. Our contribution is twofold. We first propose a formal model to describe mobile robot protocols operating in a discrete space i.e., with a finite set of possible robot positions, under synchrony and asynchrony assumptions. We translate this formal model into the DVE language, which is the input format of the model-checkers DiVinE and ITS tools, and formally prove the equivalence of the two models. We then verify several instances of two existing protocols for variants of the ring exploration in an asynchronous setting: exploration with stop and perpetual exclusive exploration. For the first protocol we refine the correctness bounds and for the second one, we exhibit a counter-example. This protocol is then modified and we establish the correctness of the new version with an inductive proof

Amore e follia nella narrativa breve dal Medioevo a Cervantes

Alla centralità del tema amoroso nella narrativa breve non di rado si connette o si affianca la rappresentazione dell’irrazionalità e della follia, in diversi gradi, forme e manifestazioni: dal tragico al comico, dal drammatico al grottesco, dal serio e grave al parodico e irridente. A tali tematiche, dal Medioevo a Cervantes, e alle loro differenti declinazioni – cui si oppongono specularmente, con maggiore o minore frequenza e intensità, i richiami a principi d’ordine, ragione e misura – sono dedicati i saggi di questo volume, che trae origine dal confronto e dialogo di un gruppo di studiosi di più ambiti disciplinari: Letteratura italiana (Johannes Bartuschat, Anna Maria Cabrini, Sandra Carapezza, Claude Cazalé Bérard, Cristina Zampese); Filologia romanza (Beatrice Barbiellini Amidei, Luca Sacchi); Letteratura spagnola (Antonio Gargano, Maria Rosso); Linguistica italiana (Giuseppe Polimeni)

An Integrated Cancer Prevention Strategy: the Viewpoint of the Leon Berard Comprehensive Cancer Center Lyon, France

International audienceThis article describes some of the key prevention services in the Leon Berard Comprehensive Cancer Center (CLB) Lyon, France, which are based on clinical prevention services, outreach activities, and collaboration with professional and territorial health communities. In addition, research is embedded at all stages of the prevention continuum, from understanding cancer causes through to the implementation of prevention interventions during and after cancer. Health promotion activities in the community and dedicated outpatient primary cancer prevention services for individuals at increased risk have been implemented. The CLB's experience illustrates how prevention can be integrated into the comprehensive mission of cancer centers, and how in turn, the cancer centers may contribute to bridging the current fragmentation between cancer care and the different components of primary, secondary, and tertiary prevention. With increasing cancer incidence, the shift toward integrated prevention-centered cancer care is not only key for improving population health, but this may also provide a response to the shortage of hospital staff and overcrowding in cancer services, as well as offer opportunities to reduce carbon emissions from cancer care