Mesure de la perception de la qualité audiovisuelle par analyse conjointe de signaux physiologiques

National audienceL'influence de la qualité audiovisuelle (AV) sur l'utilisateur a été étudiée à partir de l'analyse de mesures physiologiques complétant les mesures subjectives habituellement utilisées. Le présent papier propose une méthode d'analyse de ces signaux basée sur l'extraction d'indicateurs et la définition d'un modèle empirique de détection automatique (par fusion de données hétérogènes) des modifications éventuelles de l'activité physiologique en réaction à la présence de dégradations de qualité et plus globalement, à la présentation de stimuli AV. Abstract - The influence of the video quality (AV) assessment was studied upon the basis of physiological measurements in addition to subjectives measurements usually used. In this paper, we propose new indicators extracted from these signals and an empirical method (with heterogenous data fusion) for automatic detection of physiological reaction due to quality degradation or more generally in response of stimuli

Prediction Of Beef Fatty Acid Composition Using Near Infrared Spectroscopy: Effects Of Tissue And Sample Preparations

International audienceThe aims of the study were to determine the best site of bovine carcass for predicting fatty acid (FA) composition using a NIRS (near infrared spectroscopy) portable equipment and to study the effect of different methods of sample preparation. 78 animals were sampled from different types and rearing systems. Seven tissues (Longissimus thoracis, Infraspinatus, Diaphragma, Rectus abdominis, shoulder subcutaneous adipose tissue (SAT), intercostal SAT and intermuscular fat at the 5th rib) were measured after sampling and grinding in liquid nitrogen. The effect of samples preparation were measured on carcass (C0), muscle without grinding (B0), ground with a meat chopper (B1), ground with a knife mill (B2) on RA muscle. FA composition was assessed using gas chromatograph and the spectra were measured at wavelengths between 350 and 2500 nm. For adipose tissue, FA were not correctly predicted from NIRS. However, predictions were more satisfactory for the major FA (C16:0, C18:0, C18:1d9c), total saturated and monounsaturated FA of muscles. The results show a better prediction of FA composition concomitant with an increased gradient of sample homogenization. For other FA and especially polyunsaturated fatty acids, the performances were not satisfactory for quantitative purposes whatever the grinding method

Comparison between 2 Different Composite Nd3+:YVO4 Crystals in a Fibre Coupled Diode Pumped Laser

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Développement d'un système d'enlèvement de vernis par laser sur une machine de soudage automatique

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Students need to be confronted to the feedback of a milieu to learn and to be acquainted with a thought style (and teachers need to have them do so). Communication au sein du symposium "La notion de preuve en didactique : vers une épistémologie de l’ascension de l’abstrait au concret ?"

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Synchronous initiation of optical detonators by Q-switched solid laser sources

International audienceThe initiation of pyrotechnic substances by a laser light has been studied for more than 30 years. But until recently the use of this technology for defence applications encountered three main technical problems: the volume and the mass of lasers, the linear loss of optical fibres and their possible damage caused by the transport of strong laser power. Recent technical progress performed in the field of electrical and optical devices are now very promising for future opto-pyrotechnic functional chains. The objective of this paper is to present a demonstrator developed in order to initiate in a synchronous way four optical detonators and to measure the dispersion of their functioning times. It includes four compact Q-switched Nd:Cr:GSGG solid laser sources, pumped by flash lamp (energy ≃110mJ, FWHM ≃8.5 ns), two ultra-fast electro-optical selectors (based on RTP crystals) used to steer the laser beam and six optical fibre lines to transmit the laser pulses to the optical detonators. The set-up integrates also complex control and safety systems, as well as cameras allowing an optimal alignment of optical fibres. Experiments led us to initiate in a synchronous way four detonators with a mean scattering of 50 ns. The perspectives in this domain of initiation concern mainly the miniaturization and the hardening to the environments of electrical and optical components

Large-Scale Synthesis and Resolution of TRISPHAT [Tris(tetrachlorobenzenediolato) phosphate(V)] Anion

Both enantiomers of TRISPHAT anion can be obtained on a multigram scale through a novel resolution procedure. The Lambda enantiomer is isolated as the tri-n-butylammonium salt, [(n)()Bu(3)NH][Lambda-1], which is soluble in pure CHCl(3) and CH(2)Cl(2). The Delta enantiomer is prepared as the cinchonidinium derivative, which is only soluble in polar solvent mixtures (>7.5% DMSO in CHCl(3))

A new compact laser source for portable applications

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Solid State laser initiation System for a defense application

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