78 research outputs found

    Global fluctuations and Gumbel statistics

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    We explain how the statistics of global observables in correlated systems can be related to extreme value problems and to Gumbel statistics. This relationship then naturally leads to the emergence of the generalized Gumbel distribution G_a(x), with a real index a, in the study of global fluctuations. To illustrate these findings, we introduce an exactly solvable nonequilibrium model describing an energy flux on a lattice, with local dissipation, in which the fluctuations of the global energy are precisely described by the generalized Gumbel distribution.Comment: 4 pages, 3 figures; final version with minor change

    Etat de l’art en conception de systèmes persuasifs

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    International audienceBy their ability to change person's behaviors and attitudes, persuasive technologies appear as promising for overcoming societal challenges. They are based on theories and models from cognitive psychology and social psychology. The earlier works on persuasive technologies, by Fogg, identified many persuasive principles to influence user's behaviors and attitude, and thus useful for building persuasive systems. Studies on persuasive technologies also bring design methods, architectures, persuasive interfaces, and experimentation in numerous domains. The grand challenge is now to adapt persuasion to the complexity and versatility of each individual, thereby maximizing the persuasive effectiveness. We still have to build plastic persuasive technologies.Les technologies persuasives, par leur capacité à agir sur le comportement et les attitudes des individus, sont une piste prometteuse dans de nombreux domaines, comme pour le traitement des grands défis sociétaux (ex : santé, environnement, …) ou le marketing (ex : inciter l’adoption d’un service, …) qui se présentent à nous. Elles s’appuient sur des résultats obtenus en psychologie cognitive et sociale lors des dernières décennies. Les travaux sur la persuasion technologique, initiés par Fogg à la fin des années 90, ont permis d’identifier de nombreux principes de persuasion sur lesquels les nouvelles technologies peuvent s’appuyer pour influencer le comportement de leurs utilisateurs. Ces travaux ont aussi permis de mettre en œuvre des méthodes de conception, des interfaces persuasives et d’expérimenter la persuasion technologique dans des domaines variés. Le plus grand défi reste maintenant d’adapter la persuasion à la complexité et à la variabilité intra-individuelle et interindividuelle, à la versatilité de chaque individu pour optimiser l’efficacité persuasive. Il nous reste à construire des technologies persuasives plastiques

    Evaluating Usability and User Experience of AR Applications in VR Simulation

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    Validating an augmented reality application in a virtual reality simulation can offer many advantages compared to testing in real conditions and can speed up development processes. With such a simulation, developers and designers do not need to have constant physical access to the real place. They can save physical navigation, experiment with different kinds of devices and isolate testing parameters. While the validity of functional testing in virtual reality simulations is not particularly challenged, the validity of such simulations to evaluate user experience and usability, similarly as in real conditions, still needs to be assessed. We then conducted a user study to explore the validity of evaluating these criteria with a virtual reality simulation tool and the importance of simulation fidelity for that purpose. Indeed, we also seek to determine whether it is necessary to simulate the limited field of view of augmented reality glasses and if the simulation can take place in a virtual world that is not a replica of the real targeted environment. To do so, we have developed an augmented reality application for smart-homes where a user can interact with different connected objects. One group of users performed the experiment in the real place with augmented reality glasses and three other groups performed the same experiment in virtual reality with various simulation conditions (field of view and environment). Users’ subjective feedback and quantitative results only highlight very few differences between real-world conditions and simulation in virtual reality, whatever the simulation parameters used. These results suggest the interest in using virtual reality simulation to evaluate an augmented reality application but should be confirmed on other use cases and interaction tasks

    EM Monitoring and classification of IEMI and protocol-based attacks on IEEE 802.11n communication networks

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    International audienceThe development of connected devices and their daily use are today at the origin of the omnipresence of Wi-Fi wireless networks. However, these Wi-Fi networks are often vulnerable, and can be used by malicious people to disturb services, intercept sensitive data or to gain access to system. In railways, trains are now equipped with wireless communication systems for operational purposes or for passenger services. In both cases, defense strategies have to be developed to prevent misuses of the networks. The first objective of this study is to propose a monitoring solution, which is independent of the communication networks, to detect the occurrence of attacks. The second objective is to develop a method able to classify attacks of different types: the intentional electromagnetic interference (IEMI), i.e., jamming attacks, and the protocol-based attacks. This study focuses on the IEEE 802.11n Wi-Fi protocol. To perform these analyses, we propose to monitor and to analyze electromagnetic (EM) signals received by a monitoring antenna and a receiver collecting EM spectra. After that, we build a classification protocol following two steps: the first consists in the construction of a Support Vector Machine (SVM) classification model using the collected spectra and the second step uses this SVM model to predict the class of the attack (if any). A time-based correction of this prediction using the nearest neighbors is also included in this second step

    Protein inactivation in mycobacteria by controlled proteolysis and its application to deplete the beta subunit of RNA polymerase

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    Using a component of the Escherichia coli protein degradation machinery, we have established a system to regulate protein stability in mycobacteria. A protein tag derived from the E. coli SsrA degradation signal did not affect several reporter proteins in wild-type Mycobacterium smegmatis or Mycobacterium tuberculosis. Expression of the adaptor protein SspB, which recognizes this modified tag and helps deliver tagged proteins to the protease ClpXP, strongly decreased the activities and protein levels of different reporters. This inactivation did not occur when the function of ClpX was inhibited. Using this system, we constructed a conditional M. smegmatis knockdown mutant in which addition of anhydrotetracycline (atc) caused depletion of the beta subunit of RNA polymerase, RpoB. The impact of atc on this mutant was dose-dependent. Very low amounts of atc did not prevent growth but increased sensitivity to an antibiotic that inactivates RpoB. Intermediate amounts of RpoB knockdown resulted in bacteriostasis and a more substantial depletion led to a decrease in viability by up to 99%. These studies identify SspB-mediated proteolysis as an efficient approach to conditionally inactivate essential proteins in mycobacteria. They further demonstrate that depletion of RpoB by ∼93% is sufficient to cause death of M. smegmatis

    Multifocal Ectopic Purkinje-Related Premature Contractions: A New SCN5A-Related Cardiac Channelopathy.: MEPPC: a new SCN5A-related cardiac channelopathy

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    International audienceOBJECTIVES: The aim of this study was to describe a new familial cardiac phenotype and to elucidate the electrophysiological mechanism responsible for the disease. BACKGROUND: Mutations in several genes encoding ion channels, especially SCN5A, have emerged as the basis for a variety of inherited cardiac arrhythmias. METHODS: Three unrelated families comprising 21 individuals affected by multifocal ectopic Purkinje-related premature contractions (MEPPC) characterized by narrow junctional and rare sinus beats competing with numerous premature ventricular contractions with right and/or left bundle branch block patterns were identified. RESULTS: Dilated cardiomyopathy was identified in 6 patients, atrial arrhythmias were detected in 9 patients, and sudden death was reported in 5 individuals. Invasive electrophysiological studies demonstrated that premature ventricular complexes originated from the Purkinje tissue. Hydroquinidine treatment dramatically decreased the number of premature ventricular complexes. It normalized the contractile function in 2 patients. All the affected subjects carried the c.665G>A transition in the SCN5A gene. Patch-clamp studies of resulting p.Arg222Gln (R222Q) Nav1.5 revealed a net gain of function of the sodium channel, leading, in silico, to incomplete repolarization in Purkinje cells responsible for premature ventricular action potentials. In vitro and in silico studies recapitulated the normalization of the ventricular action potentials in the presence of quinidine. CONCLUSIONS: A new SCN5A-related cardiac syndrome, MEPPC, was identified. The SCN5A mutation leads to a gain of function of the sodium channel responsible for hyperexcitability of the fascicular-Purkinje system. The MEPPC syndrome is responsive to hydroquinidine

    EuReCa ONE—27 Nations, ONE Europe, ONE Registry A prospective one month analysis of out-of-hospital cardiac arrest outcomes in 27 countries in Europe

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    AbstractIntroductionThe aim of the EuReCa ONE study was to determine the incidence, process, and outcome for out of hospital cardiac arrest (OHCA) throughout Europe.MethodsThis was an international, prospective, multi-centre one-month study. Patients who suffered an OHCA during October 2014 who were attended and/or treated by an Emergency Medical Service (EMS) were eligible for inclusion in the study. Data were extracted from national, regional or local registries.ResultsData on 10,682 confirmed OHCAs from 248 regions in 27 countries, covering an estimated population of 174 million. In 7146 (66%) cases, CPR was started by a bystander or by the EMS. The incidence of CPR attempts ranged from 19.0 to 104.0 per 100,000 population per year. 1735 had ROSC on arrival at hospital (25.2%), Overall, 662/6414 (10.3%) in all cases with CPR attempted survived for at least 30 days or to hospital discharge.ConclusionThe results of EuReCa ONE highlight that OHCA is still a major public health problem accounting for a substantial number of deaths in Europe.EuReCa ONE very clearly demonstrates marked differences in the processes for data collection and reported outcomes following OHCA all over Europe. Using these data and analyses, different countries, regions, systems, and concepts can benchmark themselves and may learn from each other to further improve survival following one of our major health care events

    L’adaptation pour une persuasion durable

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    International audienceMaking people change is difficult; making them change for ever is all the more challenging. We explore adaptation as a means for bringing diversity and thereby for killing the annoying effect of persuasive messages. The case study is TILT, a persuasive application dedicated to smartphone usage regulation. We show that adapting persuasion increases efficiency.Persuader est difficile ; persuader sur la durée l’est encore plus. Nous explorons l’adaptation pour apporter de la variété et de la pertinence à la persuasion et ainsi pallier l’usure de l’efficacité des messages persuasifs. Le cas d’étude est TILT, un dispositif persuasif pour la régulation du temps d’usage du smartphone. La persuasion de TILT s’appuie sur le principe d’auto-surveillance. L’expérimentation démontre la pertinence de l’adaptation du message persuasif comme renfort de l’efficacité du principe d’auto-surveillance dans le temps
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