9 research outputs found

    Viability-based computation of spatially constrained minimum time trajectories for an autonomous underwater vehicle: implementation and experiments.

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    A viability algorithm is developed to compute the constrained minimum time function for general dynamical systems. The algorithm is instantiated for a speciïŹc dynamics(Dubin’s vehicle forced by a ïŹ‚ow ïŹeld) in order to numerically solve the minimum time problem. With the speciïŹc dynamics considered, the framework of hybrid systems enables us to solve the problem efïŹciently. The algorithm is implemented in C using epigraphical techniques to reduce the dimension of the problem. The feasibility of this optimal trajectory algorithm is tested in an experiment with a Light Autonomous Underwater Vehicle (LAUV) system. The hydrodynamics of the LAUV are analyzed in order to develop a low-dimension vehicle model. Deployment results from experiments performed in the Sacramento River in California are presented, which show good performance of the algorithm.trajectories; underwater vehicle; viability algorithm; hybrid systems; implementation;

    Network of automated vehicles: the AutoNet 2030 vision

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    electronic proceedingsInternational audienceAutoNet2030 - Co-operative Systems in Support of Networked Automated Driving by 2030 - is a European project connecting two domains of intensive research: cooperative systems for Intelligent Transportation Systems and Automated Driving. Given the latest developments in the standardization of vehicular communications, vehicles will soon be wirelessly connected, enabling cooperation among them and with the infrastructure. At the same time, some vehicles will offer very advanced driving assistance systems, ranging from Cooperative Adaptive Cruise Control (C-ACC) to full automation. The research issues addressed in AutoNet2030 are as follows: how can all these vehicles with different capabilities most efficiently cooperate to increase safety and fluidity of the traffic system? What kind of information should be exchanged? Which organization (e.g. centralized or distributed) is the best? The purpose of this paper is to introduce the vision and concepts underlying the AutoNet2030 project and the direction of this ongoing research work

    ALMACAL VI: Molecular gas mass density across cosmic time via a blind search for intervening molecular absorbers

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    We are just starting to understand the physical processes driving the dramatic change in cosmic star-formation rate between z ∌ 2 and the present day. A quantity directly linked to star formation is the molecular gas density, which should be measured through independent methods to explore variations due to cosmic variance and systematic uncertainties. We use intervening CO absorption lines in the spectra of mm-bright background sources to provide a census of the molecular gas mass density of the Universe. The data used in this work are taken from ALMACAL, a wide and deep survey utilizing the ALMA calibrator archive. While we report multiple Galactic absorption lines and one intrinsic absorber, no extragalactic intervening molecular absorbers are detected. However, thanks to the large redshift path surveyed (Δz = 182), we provide constraints on the molecular column density distribution function beyond z ∌ 0. In addition, we probe column densities of N(H2) > 1016 atoms cm−2, five orders of magnitude lower than in previous studies. We use the cosmological hydrodynamical simulation IllustrisTNG to show that our upper limits of ρ(H2) â‰Č 108.3M⊙Mpc−3 at 0 < z ≀ 1.7 already provide new constraints on current theoretical predictions of the cold molecular phase of the gas. These results are in agreement with recent CO emission-line surveys and are complementary to those studies. The combined constraints indicate that the present decrease of the cosmic star-formation rate history is consistent with an increasing depletion of molecular gas in galaxies compared to z ∌ 2

    Network of automated vehicles: The AutoNet2030 vision

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    AutoNet2030 – Co-operative Systems in Support of Networked Automated Driving by 2030 – is a European project connecting two domains of intensive research: cooperative systems for Intelligent Transportation Systems and Automated Driving. Given the latest developments in the standardization of vehicular communications, vehicles will soon be wirelessly connected, enabling cooperation among them and with the infrastructure. At the same time, some vehicles will offer very advanced driving assistance systems, ranging from Cooperative Adaptive Cruise Control (C-ACC) to full automation. The research issues addressed in AutoNet2030 are as follows: how can all these vehicles with different capabilities most efficiently cooperate to increase safety and fluidity of the traffic system? What kind of information should be exchanged? Which organization (e.g. centralized or distributed) is the best? The purpose of this paper is to introduce the vision and concepts underlying the AutoNet2030 project and the direction of this ongoing research work

    L’apprentissage au secours de la rĂ©duction de dimension pour des problĂšmes d’optimisation

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    peer reviewedPour assurer la stabilitĂ© du rĂ©seau Ă©lectrique, la production doit ĂȘtre ajustĂ©e en quasi temps rĂ©el Ă  la consommation. Cet ajustement ne peut porter que sur un nombre limitĂ© de centrales et doit ĂȘtre effectuĂ© dans des dĂ©lais rĂ©duits. La combinatoire du problĂšme rend la recherche d’un optimum Ă©conomique par des mĂ©thodes d’optimisation classiques trĂšs difficile. Ce travail cherche Ă  montrer l’intĂ©rĂȘt d’utiliser des algorithmes d’apprentissage supervisĂ© performants comme le Boosting, pour sĂ©lectionner les centrales Ă  redĂ©clarer. Cette sĂ©lection prĂ©alable permet ensuite de rĂ©duire considĂ©rablement le temps de l’optimisation des programmes de production tout en garantissant l’optimalitĂ© Ă©conomique

    BIOINSPIRED CATALYSIS USING OLIGOUREA HELICAL FOLDAMERS CATALYSE BIO-INSPIRÉE UTILISANT DES FOLDAMÈRES HÉLICOÏDAUX D'OLIGO-URÉE

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    (EN)The present description provides oligourea catalysts, a polar helical oligomeric strands, and methods for catalyzing reactions with polar helical oligomeric strands and oligourea catalysts. In particular, the invention relates to a polar helical oligomeric strand of at least 4 residues selected from the formula (I) and which can be used as a catalyst. (FR)La prĂ©sente invention concerne des catalyseurs d'oligo-urĂ©e, des brins oligomĂšres hĂ©licoĂŻdaux polaires, et des procĂ©dĂ©s de catalyse de rĂ©actions utilisant lesdits brins oligomĂšres hĂ©licoĂŻdaux polaires et catalyseurs d'oligo-urĂ©e. En particulier, l'invention concerne un brin oligomĂšre hĂ©licoĂŻdal polaire d'au moins 4 rĂ©sidus choisi d'aprĂšs la formule (I) et qui peut ĂȘtre utilisĂ© comme catalyseur

    Stellar and weak lensing profiles of massive galaxies in the Hyper-Suprime Cam survey and in hydrodynamic simulations

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    We perform a consistent comparison of the mass and mass profiles of massive (M⋆ > 1011.4 M⊙) central galaxies at z ∌ 0.4 from deep Hyper Suprime-Cam (HSC) observations and from the Illustris, TNG100, and Ponos simulations. Weak lensing measurements from HSC enable measurements at fixed halo mass and provide constraints on the strength and impact of feedback at different halo mass scales. We compare the stellar mass function (SMF) and the Stellar-to-Halo Mass Relation (SHMR) at various radii and show that the radius at which the comparison is performed is important. In general, Illustris and TNG100 display steeper values of α where M⋆∝Mαvir⁠. These differences are more pronounced for Illustris than for TNG100 and in the inner rather than outer regions of galaxies. Differences in the inner regions may suggest that TNG100 is too efficient at quenching in situ star formation at Mvir ≃ 1013 M⊙ but not efficient enough at Mvir ≃ 1014 M⊙. The outer stellar masses are in excellent agreement with our observations at Mvir ≃ 1013 M⊙, but both Illustris and TNG100 display excess outer mass as Mvir ≃ 1014 M⊙ (by ∌0.25 and ∌0.12 dex, respectively). We argue that reducing stellar growth at early times in M⋆∌109−10M⊙ galaxies would help to prevent excess ex-situ growth at this mass scale. The Ponos simulations do not implement AGN feedback and display an excess mass of ∌0.5 dex at r < 30 kpc compared to HSC which is indicative of overcooling and excess star formation in the central regions. The comparison of the inner profiles of Ponos and HSC suggests that the physical scale over which the central AGN limits star formation is r â‰Č 20 kpc. Joint comparisons between weak lensing and galaxy stellar profiles are a direct test of whether simulations build and deposit galaxy mass in the correct dark matter haloes and thereby provide powerful constraints on the physics of feedback and galaxy growth. Our galaxy and weak lensing profiles are publicly available to facilitate comparisons with other simulations

    Rare predicted loss-of-function variants of type I IFN immunity genes are associated with life-threatening COVID-19

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    BackgroundWe previously reported that impaired type I IFN activity, due to inborn errors of TLR3- and TLR7-dependent type I interferon (IFN) immunity or to autoantibodies against type I IFN, account for 15-20% of cases of life-threatening COVID-19 in unvaccinated patients. Therefore, the determinants of life-threatening COVID-19 remain to be identified in similar to 80% of cases.MethodsWe report here a genome-wide rare variant burden association analysis in 3269 unvaccinated patients with life-threatening COVID-19, and 1373 unvaccinated SARS-CoV-2-infected individuals without pneumonia. Among the 928 patients tested for autoantibodies against type I IFN, a quarter (234) were positive and were excluded.ResultsNo gene reached genome-wide significance. Under a recessive model, the most significant gene with at-risk variants was TLR7, with an OR of 27.68 (95%CI 1.5-528.7, P=1.1x10(-4)) for biochemically loss-of-function (bLOF) variants. We replicated the enrichment in rare predicted LOF (pLOF) variants at 13 influenza susceptibility loci involved in TLR3-dependent type I IFN immunity (OR=3.70[95%CI 1.3-8.2], P=2.1x10(-4)). This enrichment was further strengthened by (1) adding the recently reported TYK2 and TLR7 COVID-19 loci, particularly under a recessive model (OR=19.65[95%CI 2.1-2635.4], P=3.4x10(-3)), and (2) considering as pLOF branchpoint variants with potentially strong impacts on splicing among the 15 loci (OR=4.40[9%CI 2.3-8.4], P=7.7x10(-8)). Finally, the patients with pLOF/bLOF variants at these 15 loci were significantly younger (mean age [SD]=43.3 [20.3] years) than the other patients (56.0 [17.3] years; P=1.68x10(-5)).ConclusionsRare variants of TLR3- and TLR7-dependent type I IFN immunity genes can underlie life-threatening COVID-19, particularly with recessive inheritance, in patients under 60 years old
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