What is about future high speed power line communication systems for in-vehicles networks?

International audienceThis paper deals with alternative automotive networks involved by the X-by-wire and X-tainment applications. New market demands like navigation, multimedia, security, safety and individualized options introduce more and more electronic control units. Furthermore, the automotive industry has to face a great challenge in its transition from mechanical engineering towards mechatronical products. In the last decades, the power line technology has received an increasing attention and spans several applications both in indoor, outdoor and in-vehicle data communications. To fulfil theses demands of intra-car communications, techniques based on power line communication (PLC) seem to be a good candidate. These techniques offer both high data rate and good adequacy with power line properties. This paper revisits the work carried out in using PLC within the automotive domain. Different solutions are discussed and results are given for different applications

Future High Speed In-Vehicle PLC Networks

International audienceThis paper deals with power line communication in vehicle (PLC). PLC is a very promising communication solution in order to offer future in-vehicle applications without increasing wiring harnesses. We join recent additional measurements which have been carried out using modified indoor PLC modems. These PLC modems are based on the two main technologies, HomePLUG AV and HDPLC

Non-Fickian dispersion in porous media : 2. Model validation from measurements at different scales

International audienceWe aim at testing and validating a mobile-immobile mass transfer model from a set of single-well injection withdrawal tracer tests in a heterogeneous porous aquifer. By varying the duration of the injection phase, different volumes of aquifer are investigated by the tracer. Hence, we focus the transport model validation not only on reproducing a single breakthrough curve (BTC) but also on the model's capacity to predict the amount of mixing as a function of the volume visited by the tracer. All the BTCs are strongly asymmetric, as expected when dispersion is controlled by diffusive mass transfers between the mobile water and the immobile water part of the porosity. However, the BTC cannot be modeled by a conventional mobile-immobile mass transfer model with a simple power law memory function. To account for that, we implement a continuous time random walk model in which the transition time distribution y (t), which is related to the excursion time probability of the tracer in the immobile domain, is a dual-slope power law distribution. The model best fits the BTC data set with a transitional regime controlled by y(t) t2 and an asymptotic regime characteristic of the conventional double-porosity model with y(t) t1.5 . This work emphasizes that high-resolution concentration measurement and multiple-scale tracer tests are required for assessing solute dispersion models in heterogeneous reservoirs and for subsequently obtaining reliable predictions

Power Line Communication standards for in-vehicle networks

International audienceThis paper deals with the in-vehicle networks. We propose to study a network which do not need new wires called Power Line Communication (PLC). Indeed, the automotive communication networks has evolved and the electronic devices in-vehicle are widespread. For example, drive-by-wire systems have actuators, engine, sensor and microprocessor to replace mechanical or hydraulic systems in vehicles. Moreover, electronic control unit (ECU) communicates and exchanges data. These needs of data sharing between ECU or between new services like multimedia involve to research new buses of communication with high throughputs. The CAN, LIN and FlexRay are wire protocols of communication usually used in the same vehicles and FlexRay has the highest throughput (10 Mbps). It appears that with the increase of electronic devices there is a wire harness bottleneck. To reduce wires and to have high throughputs (> 10 Mbps), we propose to study the feasibility of PLC indoor standards in-vehicles. PLC are usually used in indoor networks. In this paper, a comparison of two PLC standards with throughput measurements thanks to commercial PLC modem in-vehicle is carried out: HomePlug Av (HPAV) and High Definition Power Line Communication (HD-PLC)

Choosing security elements for the xAAL home automation system

International audienceThe emergence of Internet of Things (IoT) and smart-home systems allows us to combine devices from different domains and to explore new usages and services. Unfortunately interoperability between devices from different technologies is a major issue to overcome before being able to offer smart services. For this purpose we have proposed the xAAL system. It is both a federating home-automation protocol and an open infrastructure designed to address issues caused by the heterogeneity of existing home-automation solutions. xAAL has been implemented, deployed and has proved its efficiency. However, early versions have been designed with functional concerns in mind. The time has come to address security. xAAL has its own specificities: a distributed system, multicast communications on a bus, etc. This paper details choices, compromises and motivations for selecting security elements that have been introduced in the new version of xAAL

A Transparent home Sensors/Actuators layer for Health & Well-being services

International audienceRisks factor leading to type 2 diabetes and cardiovascular diseases can be reduced by a preventive care infrastructure able to modify the habits toward healthier lifestyles, including more exercise, a better diet and a reduced stress. Accessing the home space is important not only to monitor indoor environment quality (IEQ) but also to provide relevant user's feedback and engage users towards a healthy life style. This paper present a new preventive care infrastructure composed of a distributed infrastructure for heterogeneous devices in the home local area network (named xAAL) in conjunction with a machine to machine protocol (MQTT) to external health & well-being services

Modem bi-mode CPL/RF pour réseau embarqué dans les véhicules automobiles

National audienceLe marché de l'automobile se tourne de plus en plus vers des solutions électroniques pour la sécurité, pour remplacer les fonctions mécaniques, pour le multimédia, etc. Ces nouvelles fonctionnalités ont cependant besoin de communiquer entre elles. Ainsi les réseaux de communications intra-véhicule sont de plus en plus nombreux comme le CAN ou le FlexRay (10 Mbps). Toutefois, de nouveaux bus de communication sont nécessaires pour à la fois réduire le nombre de câbles (e.g. certaines voitures peuvent avoir jusqu'à 3 km de câbles pesant alors environ 50 kg) et augmenter les débits. Notre étude porte sur la démonstration de la faisabilité de nouveaux bus de communication utilisant un médium de communication Radio Fréquence (RF) et Courant Porteur en Ligne (CPL). Aucun nouveau câble n'est ajouté et les standards utilisés en Indoor comme le WiFi et l'HomePlug Av (CPL) permettent d'envisager des débits élevés. Des mesures de débit effectuées au sein d'une Peugeot 407 SW démontrent la faisabilité de ces solutions. En ce qui concerne le CPL, nous avons adapté des modems du commerce utilisés en Indoor pour les coupler au réseau électrique de la voiture. Nos premières expérimentations nous ont permis d'avoir des débits supérieurs à 10 Mbps (voiture éteinte). Des mesures de débit pour une communication WiFi (norme IEEE 802.11g) ont aussi été faites et nous avons constaté un débit moyen de 11 Mbps (voiture éteinte ou en mouvement). Remarquons enfin que ces débits mesurés sont supérieurs à ceux du FlexRay

A Data Oriented Approach for Real-Time Systems

International audienceDistributed real-time systems often have to maintain the temporal validity of data. In this paper we present a modelling framework centered on data where a so-called observation relation represents and abstracts the interactions between variables. An observation is a relation between variables, an image and its sources, where the image values depend on past values of the sources. The system architecture is seen as a set of observation relations describing the flow of values between variables. The observation relations are parametrized with timed constraints that limit the time shift between the variables and specify the availability of timely sound values. At this level of abstraction, the designer gives a specification of the system based on timed properties about the timeline of data such as their freshness, latency etc. We proceed to an analysis of the feasibility of such a specification and we formally analyze the correctness of an implementation with respect to a specification. In order to prove the feasibility of an observationbased model, we build a finite state transition system which is bi-similar to the specification. The existence of an infinite execution in this system proves the feasibility of the specification. Possible implementations are described as a set of interacting components which control the flow of values in the system. A finite system is built to prove the correctness of the implementation by model checkin

Natural Cognitive Foundations of Teacher Knowledge: An Evolutionary and Cognitive Load Account

International audienceInstructional process management (encompassing instructional design and classroom management) is known to be very complex, mainly due to its context and the large and diverse amount of knowledge driving it: content knowledge, pedagogical knowledge (PK), curriculum knowledge, knowledge of learners and their characteristics, knowledge of educational contexts, pedagogical content knowledge, and knowledge of educational ends (Shulman, 1987). This complexity makes researchers unable to detect well-defined practices, and a knowledge base leading to efficient teaching with low training cost is missing (Koedinger, Booth, & Klahr, 2013). The attempts so far to investigate these pieces of knowledge can be categorised in two paths. The first path considers novice vs. expert knowledge comparisons to model knowledge growth across experience (Hogan, Rabinowitz, & Craven, 2003). The second path considers knowledge bases every teacher needs in order to work efficiently. These two paths both have some concerns. Teachers' expertise is not so clear-cut and the way teachers develop it through experience is difficult to model and diagnose. Further, specifying a comprehensive knowledge base about teaching is often externally-driven (Hattie, 2009; Wang, Haertel, & Walberg, 1993), listing a superficial knowledge base of 'what works', often unrelated to teachers' beliefs and knowledge and/or their cognitive abilities. Pedagogical Content Knowledge (PCK), as Shulman (1987, p. 8) argued, is " that special amalgam of content and pedagogy that is uniquely the province of teachers, their own special form of special understanding ". This proposition, as well as Shulman's professional knowledge development model, has become widespread in the educational sciences research field. However, some problems can be raised, notwithstanding its vagueness (" special amalgam " , also see Kind, 2015). First, teaching is mainly seen as a " learned profession " (see Shulman, 1987, p. 9), while the social and informal facet of this activity, relying on mainly innate abilities, remains unaddressed. Second, we refer to van Driel et al.'s (2001) definition of PCK: " the knowledge the teachers must have in order to teach science " (emphasis added) to highlight that the orientation of such a knowledge base is highly prescriptive in nature: it states appropriate knowledge so that anyone having it can be a good teacher, and many research lines have been oriented to differentiating novices from experts with regard to PCK. Third, this model emphasises a unidirectional way in which teachers' beliefs and knowledge 2 influence his or her social behaviour, whereas bidirectional ways are more likely to occur (Rimm-Kaufman & Hamre, 2010). The aim of this paper is to explore a cognitive way to define teachers' professional knowledge (TPK), arguing that some 'natural' knowledge, stemming from several human social abilities – and, for many of them, animal – is thus engaged in teaching as well. The actions grounded on such knowledge are undertaken automatically or at a low cognitive load due to the nature of the latter. Some theoretical views on teaching include such an assumption (Csibra, 2007; Csibra & Gergely, 2011; Strauss, 2005; Strauss & Ziv, 2012), but so far, little research has investigated teachers' cognitive processes in relation to both natural cognition and Cognitive Load Theory (CLT) (see however Feldon, 2007; Moos & Pitton, 2013). The remainder of this paper seeks firstly to consider teachers' actions through the lens of natural cognition and pedagogy, then to set up a framework for teacher cognition and knowledge, showing that several social abilities and knowledge can be used for teaching purposes, and with a low cognitive load. Then, we describe the abilities for teaching as primary vs. secondary knowledge. Eventually, we use this framework to assess or predict which cognitive load is in relation with teachers' performances according to the CLASS, a renowned classroom observation system

« Gleb » - Analyse croisée des registres sportifs et langagiers dans le cas du gouren / lutte bretonne

Les pratiques corporelles, et notamment les sports, constituent des moments particuliers de la vie sociale, ce qui se traduit dans le langage par des termes et des usages dédiés. Dans le cas de la Bretagne, les tournois de lutte (lutte bretonne ou gouren) se caractérisent par la formalisation dans le langage et la littérature orale et écrite d’une séquence narrative et d’un système d’actants, marqués par l’association symbolique avec le monde animal (notamment le maout – bélier), et un parallèle entre l’issue de l’opposition et l’opposition réelle et symbolique entre les catégories « sec » et « mouillé », d’où le titre « gleb », signifiant « mouillé » en breton.Physical activities, especially sports, represent specific moments in social life, and this is reflected in language through specific terms and usages. In the case of Brittany, wrestling tournaments (Breton wrestling, or gouren) are characterised on the one hand by the formalisation in oral and written language and literature of both a narrative sequence and a system of actants, which are marked by a symbolic association with the animal world (notably the ram, or le maout), and on the other by a parallel between the competition outcome and the real/symbolic competition between the categories ‘wet’ and ‘dry’, hence the title ‘Gleb’, meaning ‘wet’ in Breton