119 research outputs found
Trajectographie passive sonar par estimation particulaire Ă maximum de vraisemblance
Cet article introduit la technique particulaire à redistributions locales adaptatives, pour la résolution des problÚmes d'estimation à maximum de vraisemblance. La performance de la technique est illustrée sur le problÚme de trajectographie passive SONAR
Localisation par vision multi-spectrale (Application aux systÚmes embarqués)
La problĂ©matique SLAM (Simultaneous Localization and Mapping) est un thĂšme largement Ă©tudiĂ© au LAAS depuis plusieurs annĂ©es. L'application visĂ©e concerne le dĂ©veloppement d'un systĂšme d'aide au roulage sur aĂ©roport des avions de ligne, ce systĂšme devant ĂȘtre opĂ©rationnel quelques soient les conditions mĂ©tĂ©orologiques et de luminositĂ© (projet SART financĂ© par la DGE en partenariat avec principalement FLIR Systems, LatĂ©coĂšre et Thales).Lors de conditions de visibilitĂ© difficile (faible luminositĂ©, brouillard, pluie...), une seule camĂ©ra traditionnelle n'est pas suffisante pour assurer la fonction de localisation. Dans un premier temps, on se propose d'Ă©tudier l'apport d'une camĂ©ra infrarouge thermique.Dans un deuxiĂšme temps, on s'intĂ©ressera Ă l'utilisation d'une centrale inertielle et d'un GPS dans l'algorithme de SLAM, la centrale aidant Ă la prĂ©diction du mouvement, et le GPS Ă la correction des divergences Ă©ventuelles. Enfin, on intĂšgrera dans ce mĂȘme SLAM des pseudo-observations issues de l'appariement entre des segments extraits des images, et ces mĂȘmes segments contenus dans une cartographie stockĂ©e dans une base de donnĂ©es. L'ensemble des observations et pseudo-observations a pour but de localiser le porteur Ă un mĂštre prĂšs.Les algorithmes devant ĂȘtre portĂ©s sur un FPGA muni d'un processeur de faible puissance par rapport aux PC standard (400 MHz), un co-design devra donc ĂȘtre effectuĂ© entre les Ă©lĂ©ments logiques du FPGA rĂ©alisant le traitement d'images Ă la volĂ©e et le processeur embarquant le filtre de Kalman Ă©tendu (EKF) pour le SLAM, de maniĂšre Ă garantir une application temps-rĂ©el Ă 30 Hz. Ces algorithmes spĂ©cialement dĂ©veloppĂ©s pour le co-design et les systĂšmes embarquĂ©s avioniques seront testĂ©s sur la plate-forme robotique du LAAS, puis portĂ©s sur diffĂ©rentes cartes de dĂ©veloppement (Virtex 5, Raspberry, PandaBoard...) en vue de l'Ă©valuation des performancesThe SLAM (Simultaneous Localization and Mapping) problematic is widely studied from years at LAAS. The aimed application is the development of a helping rolling system for planes on airports. This system has to work under any visibility and weather conditions ("SART" project, funding by DGE, with FLIR Systems, ThalĂšs and LatecoĂšre).During some weather conditions (fog, rain, darkness), one only visible camera is not enough to complete this task of SLAM. Firstly, in this thesis, we will study what an infrared camera can bring to SLAM problematic, compared to a visible camera, particularly during hard visible conditions.Secondly, we will focus on using Inertial Measurement Unit (IMU) and GPS into SLAM algorithm, IMU helping on movement prediction, and GPS helping on SLAM correction step. Finally, we will fit in this SLAM algorithm pseudo-observations coming from matching between points retrieved from images, and lines coming from map database. The main objective of the whole system is to localize the vehicle at one meter.These algorithms aimed to work on a FPGA with a low-power processor (400MHz), a co-design between the hardware (processing images on the fly) and the software (embedding an Extended Kalman Filter (EKF) for the SLAM), has to be realized in order to guarantee a real-time application at 30 Hz. These algorithms will be experimented on LAAS robots, then embedded on different boards (Virtex 5, Raspberry Pi, PandaBoard...) for performances evaluationTOULOUSE-INSA-Bib. electronique (315559905) / SudocSudocFranceF
Selection for reduced muscle glycolytic potential in Large White pigs I. Direct responses
International audienc
Comparison between the three porcine RN genotypes for growth, carcass composition and meat quality traits
A three-step experimental design has been carried out to add evidence about the existence of the RN gene, with two segregating alleles RN- and rn+, having major effects on meat quality in pigs, to estimate its effects on production traits and to map the RN locus. In the present article, the experimental population and sampling procedures are described and discussed, and effects of the three RN genotypes on growth and carcass traits are presented. The RN genotype had no major effect on growth performance and killing out percentage. Variables pertaining to carcass tissue composition showed that the RN- allele is associated with leaner carcasses (about 1 s.d. effect without dominance for back fat thickness, 0.5 s.d. effect with dominance for weights of joints). Muscle glycolytic potential (GP) was considerably higher in RN- carriers, with a maximum of a 6.85 s.d. effect for the live longissimus muscle GP. Physico-chemical characteristics of meat were also influenced by the RN genotype in a dominant way, ultimate pH differing by about 2 s.d. between homozygous genotypes and meat colour by about 1 s.d. Technological quality was also affected, with a 1 s.d. decrease in technological yield for RN- carriers. The RN genotype had a more limited effect on eating quality. On the whole, the identity between the acid meat condition and the RN- allele effect is clearly demonstrated (higher muscle GP, lower ultimate pH, paler meat and lower protein content), and the unfavourable relationship between GP and carcass lean to fat ratio is confirmed
Selection for reduced muscle glycolytic potential in Large White pigs. II. Correlated responses in meat quality and muscle compositional traits
International audienc
A search for pre-substellar cores and proto-brown dwarf candidates in Taurus: multiwavelength analysis in the B213-L1495 clouds
In an attempt to study whether the formation of brown dwarfs (BDs) takes
place as a scaled-down version of low-mass stars, we conducted IRAM30m/MAMBO-II
observations at 1.2 mm in a sample of 12 proto-BD candidates selected from
Spitzer/IRAC data in the B213-L1495 clouds in Taurus. Subsequent observations
with the CSO at 350 micron, VLA at 3.6 and 6 cm, and IRAM30m/EMIR in the
12CO(1-0), 13CO(1-0), and N2H+(1-0) transitions were carried out toward the two
most promising Spitzer/IRAC source(s), J042118 and J041757. J042118 is
associated with a compact (<10 arcsec or <1400 AU) and faint source at 350
micron, while J041757 is associated with a partially resolved (~16 arcsec or
~2000 AU) and stronger source emitting at centimetre wavelengths with a flat
spectral index. The corresponding masses of the dust condensations are ~1 and
~5 Mjup for J042118 and J041757, respectively. In addition, about 40 arcsec to
the northeast of J041757 we detect a strong and extended submillimetre source,
J041757-NE, which is not associated with NIR/FIR emission down to our detection
limits, but is clearly detected in 13CO and N2H+ at ~7 km/s, and for which we
estimated a total mass of ~100 Mjup, close to the mass required to be
gravitationally bound. In summary, our observational strategy has allowed us to
find in B213-L1495 two proto-BD candidates and one pre-substellar core
candidate, whose properties seem to be consistent with a scaled-down version of
low-mass stars.Comment: MNRAS, 424, 2778; corrected typos, mass estimate refined in Section
3.2.1 and Section 5.3; conclusions unchange
Probing the close environment of young stellar objects with interferometry
The study of Young Stellar Objects (YSOs) is one of the most exciting topics
that can be undertaken by long baseline optical interferometry. The magnitudes
of these objects are at the edge of capabilities of current optical
interferometers, limiting the studies to a few dozen, but are well within the
capability of coming large aperture interferometers like the VLT
Interferometer, the Keck Interferometer, the Large Binocular Telescope or
'OHANA. The milli-arcsecond spatial resolution reached by interferometry probes
the very close environment of young stars, down to a tenth of an astronomical
unit. In this paper, I review the different aspects of star formation that can
be tackled by interferometry: circumstellar disks, multiplicity, jets. I
present recent observations performed with operational infrared
interferometers, IOTA, PTI and ISI, and I show why in the next future one will
extend these studies with large aperture interferometers.Comment: Review to be published in JENAM'2002 proceedings "The Very Large
Telescope Interferometer Challenges for the future
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