Towards a Decoupled Context-Oriented Programming Language for the Internet of Things

Easily programming behaviors is one major issue of a large and reconfigurable deployment in the Internet of Things. Such kind of devices often requires to externalize part of their behavior such as the sensing, the data aggregation or the code offloading. Most existing context-oriented programming languages integrate in the same class or close layers the whole behavior. We propose to abstract and separate the context tracking from the decision process, and to use event-based handlers to interconnect them. We keep a very easy declarative and non-layered programming model. We illustrate by defining an extension to Golo-a JVM-based dynamic language

Unsupervised Learning from Narrated Instruction Videos

We address the problem of automatically learning the main steps to complete a certain task, such as changing a car tire, from a set of narrated instruction videos. The contributions of this paper are three-fold. First, we develop a new unsupervised learning approach that takes advantage of the complementary nature of the input video and the associated narration. The method solves two clustering problems, one in text and one in video, applied one after each other and linked by joint constraints to obtain a single coherent sequence of steps in both modalities. Second, we collect and annotate a new challenging dataset of real-world instruction videos from the Internet. The dataset contains about 800,000 frames for five different tasks that include complex interactions between people and objects, and are captured in a variety of indoor and outdoor settings. Third, we experimentally demonstrate that the proposed method can automatically discover, in an unsupervised manner, the main steps to achieve the task and locate the steps in the input videos.Comment: Appears in: 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR 2016). 21 page

Material Emulation of Faults on Cryptoprocessors

International audienceThis paper describes a block that can be added to a crypto-processor embedded on a FPGA. This block enables to simulate the co- processor behaviour when faults are injected. Three fault models are used and an example with AES is given. The aim of such a block is to speed up the test of countermeasures on a FPGA before running the chip in fab

Étude des mécanismes d'initiation et de combustion dans des films réactifs multicouches Al/CuO : influence d'additifs et de porosité

Les thermites, matériaux énergétiques composites à base de métaux et d'oxydes, sont des candidats prometteurs pour remplacer les matériaux conventionnels (CHNO) utilisés dans les systèmes pyrotechniques actuels. En effet, ils sont capables de générer une grande quantité d'énergie chimique en un temps très court (µs) suite à un stimulus électrique, mécanique ou thermique, tout en étant plus surs. Parmi les couples thermites nouvellement explorés, les nanothermites à base d'aluminium (Al) et d'oxyde de cuivre (CuO), tous deux dans des dimensions nanométriques, présentent un réel intérêt applicatif car ils sont intégrables en technologie couche mince pour être compatibles avec l'intégration ultime et remplacer les compositions primaires des initiateurs. De plus, ce couple est caractérisé par une enthalpie de réaction parmi les plus élevée (~4 kJ.g-1) tout en étant stable à température ambiante et peu sensible aux décharges électrostatiques. Au LAAS, un procédé de dépôt de nanothermites Al/CuO couche mince est disponible par pulvérisation cathodique, développé lors de thèses précédentes et aujourd'hui exploité pour fabriquer des microdispositifs d'initiation pour des applications diverses. Les exigences industrielles nécessitent de, non seulement contrôler les propriétés énergétiques (énergie initiation et température flamme) de ces matériaux, mais aussi de les moduler précisément pour répondre à la variété des cahiers de charges applicatifs. Dans ce contexte, cette thèse a eu pour objectif de consolider la compréhension des mécanismes d'initiation et de combustion dans les couches minces Al/CuO et d'étudier le rôle des contraintes qui sont inhérentes aux procédés de dépôt du matériau. Particulièrement, nous avons travaillé sur les multicouches Al/CuO classiquement utilisées dans les dispositifs, s'agissant d'empilement de 10-15 couches minces d'Al et de CuO (~100-200 nm d'épaisseur). Nous avons, d'une part, proposés des voies technologiques intéressantes et nouvelles pour moduler les propriétés énergétiques de ces matériaux, par l'ajout d'additifs comme des nanoparticules d'or ou micro-pores. Nous avons ensuite étudié l'influence de l'ajout de ces additifs sur les mécanismes d'initiation et de combustion. Ce travail a nécessité de corréler caractérisations macroscopiques (vitesse de combustion, temps d'initiation) et observations aux échelles microscopiques et même atomique en faisant appel à des techniques microscopie électronique hautement résolue pour comprendre la relation entre modification de la microstructure et propriétés énergétiques (initiation et combustion). Nous avons aussi élaboré des modèles physiques simples dès que nécessaire pour supporter les observations expérimentales.Thermites, composite energetic materials based on metals and oxides, are promising candidates to replace conventional materials (CHNO) used in current pyrotechnic systems. Indeed, they are able to generate a large amount of chemical energy in a very short time (µs) following an electrical, mechanical or thermal stimulus, while being safer. Among the newly explored thermite couples, aluminium (Al) and copper oxide (CuO) based nanothermites, both in nanometric dimensions, present a real applicative interest because they can be integrated in thin film technology to be compatible with the ultimate integration and replace the primary compositions of the initiators. Moreover, this couple is characterized by an enthalpy of reaction among the highest (~4 kJ/g) while being stable at room temperature and not very sensitive to electrostatic discharges. At LAAS, a thin film Al/CuO nanothermite deposition process is available by sputtering, developed during previous thesis works, and now used to fabricate ignition microdevices for various applications. The industrial requirements require not only to control the energetic properties (ignition energy and flame temperature) of these materials, but also to modulate them precisely in order to fit the variety of application specifications. In this context, the objective of this thesis was to consolidate the understanding of ignition and combustion mechanisms in Al/CuO thin films and to study the role of the constraints inherent to the deposition processes of the material. In particular, we have worked on Al/CuO multilayers typically used in devices, being stacks of 10-15 thin layers of Al and CuO (~100-200 nm thick). We have proposed interesting and new technological ways to modulate the energetic properties of these materials, by adding additives such as gold nanoparticles or micro-pores. We then studied the influence of the addition of these additives on the ignition and combustion mechanisms. This work required to correlate macroscopic characterizations (burning rate, ignition time) and observations at microscopic and even atomic scales using highly resolved electron microscopy techniques to understand the relationship between microstructure modification and energetic properties (ignition and combustion). We also developed simple physical models as soon as necessary to support the experimental observations

Study of geopolymerization mechanisms by 27Al-NMR and calorimetry correlation

Geopolymers are alumino-silicate binders prepared by reacting a powdered alumino-silicate source (metakaolin) with an alkali silicate “activating” solution. The geopolymerization reaction is a complex process but it is consensual that geopolymers are formed by dissolution of the metakaolin and condensation reactions between silicates and aluminates initially in solution or as dissolution products. However, those two processes occur concomitantly during the geopolymerization. It makes it difficult to study geopolymerization mechanisms in detail for kinetics or thermodynamics purposes. This could explain why detailed mechanistic descriptions are scarce in the literature and why this topic is still a matter of debate. In this study, an experimental method highlighting the different mechanisms involved in the geopolymerization is proposed, allowing the determination of a thermodynamic parameter of the system. The different processes constituting the geopolymerization were dissociated by varying the metakaolin content in geopolymers, for a given activating solution. Reactivity of such mixes was investigated by isothermal conduction microcalorimetry (ICC). Time resolved 27Al static Nuclear Magnetic Resonance (NMR) was used to monitor the concentration of aluminate centers in solution during the reaction. The correlation as function of time of the total heat release measured by ICC with the aluminate centers concentration in solution exhibited the existence of a master curve allowing the determination of a reaction enthalpy. The influence of alkali cations, silicate species and aluminate ions on this reaction enthalpy was then investigated. For the first time, the dependence of the geopolymer thermodynamics over the initial composition of the system was highlighted

Emergent spatial structures in flocking models: a dynamical system insight

We show that hydrodynamic theories of polar active matter generically possess inhomogeneous traveling solutions. We introduce a unifying dynamical-system framework to establish the shape of these intrinsically nonlinear patterns, and show that they correspond to those hitherto observed in experiments and numerical simulations: periodic density waves, and solitonic bands, or polar-liquid droplets both cruising in isotropic phases. We elucidate their respective multiplicity and mutual relations, as well as their existence domain

New insights into the role of hydroxide ions and silicate species during geopolymerization

The specific role of hydroxide ions in highly alkaline silicate solutions has been hardly investigated due to the difficulty to quantify them. In this study, Hammet acidity functions of sodium silicate solutions have been assessed for the first time. The low acidity function values found in these solutions, when compared to pure sodium hydroxide solutions, has been explained by the buffering effect of silicate species using liquid state 29Si NMR. Such a parameter has then been used to quantify the hydroxide ions ability to react during mixing alkali silicate solutions with metakaolin. Despite lower initial acidity function values for equivalent sodium hydroxide additions when compared to silicate-free solutions, it has been demonstrated that dissolution of the studied metakaolin is much more efficient in presence of silicate species. Such a phenomenon has been attributed to the gradual release of hydroxide ions resulting from silicate species condensation during the metakaloin dissolution

Effect of cerium on structure modifications of a hybrid sol–gel coating, its mechanical properties and anti-corrosion behavior

An organic–inorganic hybrid coating was developed to improve the corrosion resistance of the aluminum alloy AA 2024-T3. Organic and inorganic coatings derived from glycidoxypropyltrimethoxysilane (GPTMS) and aluminum tri-sec-butoxide Al(OsBu)3, with different cerium contents, were deposited onto aluminum by dip-coating process. Corrosion resistance and mechanical properties were investigated by electrochemical impedance measurements and nano-indentation respectively. An optimal cerium concentration of 0.01 M was evidenced. To correlate and explain the hybrid coating performances in relation to the cerium content, NMR experiments were performed. It has been shown that when the cerium concentration in the hybrid is higher than 0.01 M there are important modifications in the hybrid structure that account for the mechanical properties and anti-corrosion behavior of the sol–gel coating

Searching for faint companions with VLTI/PIONIER. II. 92 main sequence stars from the Exozodi survey

The Exozodi survey aims to determine the occurrence rate of bright exozodiacal discs around nearby main sequence stars using infrared interferometry. Although the Exozodi survey targets have been carefully selected to avoid the presence of binary stars, the results of this survey can still be biased by the presence of unidentified stellar companions. Using the PIONIER data set collected within the Exozodi survey, we aim to search for the signature of point-like companions around the Exozodi target stars. We use both the closure phases and squared visibilities collected by PIONIER to search for companions within the ~100 mas interferometric field of view. The presence of a companion is assessed by computing the goodness of fit to the data for a series of binary models with various separations and contrasts. Five stellar companions are resolved for the first time around five A-type stars: HD 4150, HD 16555, HD 29388, HD 202730, and HD 224392 (although the companion to HD 16555 was independently resolved by speckle interferometry while we were carrying out the survey). In the most likely case of main sequence companions, their spectral types range from A5V to K4V. Three of these stars were already suspected to be binaries from Hipparcos astrometric measurements, although no information was available on the companions themselves so far. In addition to debiasing the statistics of the Exozodi survey, these results can also be used to revise the fraction of visual binaries among A-type stars, suggesting that an extra ~13% A-type stars are visual binaries in addition to the ones detected in previous direct imaging surveys. We estimate that about half the population of nearby A-type stars could be resolved as visual binaries using a combination of state-of-the-art interferometry and single-aperture imaging, and we suggest that a significant fraction of these binaries remains undetected to date.Comment: Accepted for publication in A&