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International audience; The paper after briefly surveying main asynchronous models in cellular automata will report recent developments in the study of m-ACA, a new general framework for studying asynchrony in cellular spaces.

International audience

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Les circuits courts alimentaires se sont beaucoup diversifiés dans la période récente, avec le soutien de l’action publique, favorisant une diversification des acheteurs. L’objectif de cette communication est d’explorer en quoi, à quelles conditions et avec quels effets l’entrée dans les circuits courts, par des consommateurs « ordinaires », peut contribuer à leur redonner du pouvoir sur leur consommation et, par-là, modifier leurs pratiques dans un sens favorable au développement durable. Ancrée en sociologie économique et des réseaux, cette exploration est basée sur le suivi, dans la durée, d’une diversité de consommateurs amenés à fréquenter un marché de plein vent doté d’un système d’étiquetage signalant l’origine des produits, contrôlé de manière participative. Nous montrons comment l’émergence de pratiques durables se comprend dans le cadre d’un nouveau système d’interactions et de relations généré par la fréquentation du marché et étayé par le dispositif d’étiquetage. Nous explorons en quoi ce système contribue à recomposer le rapport des personnes aux produits alimentaires et à l’acte d’achat. Le consommateur ordinaire en transition émerge en tant que sujet, ancré dans son territoire de vie, prenant le pouvoir sur sa consommation en devenant partie prenante de son système alimentaire. Cette exploration appelle à approfondir, à partir des circuits courts, la construction sociale de différents dispositifs de démocratie alimentaire pour favoriser la transition des systèmes alimentaires vers des systèmes plus durables.

This paper describes the model UdL we proposed to solve the semantic textual similarity task of SemEval 2017 workshop. The track we participated in was estimating the semantics relatedness of a given set of sentence pairs in English. The best run out of three submitted runs of our model achieved a Pearson correlation score of 0.8004 compared to a hidden human annotation of 250 pairs. We used random forest ensemble learning to map an expandable set of extracted pairwise features into a semantic similarity estimated value bounded between 0 and 5. Most of these features were calculated using word embedding vectors similarity to align Part of Speech (PoS) and Name Entities (NE) tagged tokens of each sentence pair. Among other pairwise features, we experimented a classical tf-idf weighted Bag of Words (BoW) vector model but with character-based range of n-grams instead of words. This sentence vector BoW-based feature gave a relatively high importance value percentage in the feature importances analysis of the ensemble learning.

International audience; Identification of materials in a planetological scene observed by an imaging spectrometer is a common problem in remote sensing. Usually the pixel size is larger than the typical size of material change over planets, leading to a linear spatial mixing. We propose here an unsupervised approach based on source separation methods to estimate the pure spectra of the components present in the observed scene and their abundances in each pixel. Previous studies have shown that this approach is interesting for Martian ices. This method assumes the positivity of both the pure spectra and the mixing coefficients. We propose here to apply this technique to detect Martian minerals and we show that adding the sum-to-one constraint (or additivity constraint) on the abundance vectors allows one to improve the estimation performance.

International audience; This paper describes the control system and user command interfaces developed for a lightweight, compact, endoscope camera manipulator prototype for robot-assistedminimally invasive surgery. A complete teleoperated minimallyinvasive surgical system in development is also based on using lightweight, compact manipulators with simple, reliable, and robust controllers. The endoscope manipulator is controlled by a single-board computer and individual motor controllers. The single-board computer processes user commands and generates control mode and analog velocity commands for the motor controllers. A miniature keypad attached to one of the surgical instruments and a voice recognition system with a foot pedal are used asuser command interfaces.

International audience; Interaction of light and sound in tiny optical cavities and waveguides is a vibrant topic nowadays, as for instance manifested in cavity optomechanics, but also in Brillouin scattering measurements in micro-wires and tapered optical fibers. Indeed, both optical and elastic wave fields are tightly confined to a very small volume and surface effects can become significant with the size reduction. Recent progress has shown that opto-acoustic interactions can benefit from the combination of the photoelastic and of the moving-interface effects. While the photoelastic effect is classical in bulk acousto-optics, the moving-interface effect is specifically driven by the vibrations of surfaces of a resonator or a waveguide. Assuming a photonic mode and a phononic mode are known beforehand, the diffraction efficiency for the creation of new photons can be estimated by overlap integrals. Reciprocally, the confined optical fields exert mechanical forces on the material composing the cavity. In order to describe this effect, we propose a variational principle describing the acousto-optical interaction. We construct a 3-wave Lagrangian describing the interaction of the original optical wave, the Doppler-shifted optical wave, and the acoustic phonons. The three waves are further phased-matched in waveguides. The Lagrangian exhibits both volume and surface contributions to the interaction energy. First, electrostriction results in a bulk force governed by the photoelastic tensor. Second, coupling of the electromagnetic field with the mechanical motion of the cavity further results in an effective surface force. We then solve the resulting elastodynamic equation subject to bulk and surface optical forces. A finite element model is specifically derived from the variational formulation. It is applied to acousto-optical (or optomechanical) interactions in a nanoscale silicon photonic cavity and in a silica micro-wire. The simulation results show that acoustic resonances can be excited all-optically in the multi-gigahertz range from infrared light. Significantly, the excited acoustic phonons are not necessarily unique normal modes of the structure, but their distribution is found to be governed by the spatial distribution of the optical forces. The finite element model is further applied to tiny optical waveguides and compared to experiments performed with silica micro-fibers, revealing the generation of surface acoustic waves propagation at the waveguide boundaries.

International audience; Metamorphic modular robots are versatile systems composed of a set of independent modules. These modules are able to deliberately change their overall topology in order to adapt to new circumstances, perform new tasks, or recover from damage. The modules considered in this paper are cubic shapes, and we assume that each of them has a separate computational resources and it is equipped with a specialized sensors to perceive the environment. In this paper, we demonstrate the ability of these robots to evolve the topology of the whole structure in order to achieve, surround and transport target objects dispersed in the environment. While performing its task, the robot may be splitted into several parts in order to cope with environmental variations. Our work integrates a simplified model of biological hormone system to generate inputs for a finite-state machine (FSM) that controls the evolution process.