搜索结果：Revue des maladies respiratoires

The Recursive KalmanNet, recently introduced by the authors, is a recurrent neural network guided by a Kalman filter, capable of estimating the state variables and error covariance of stochastic dynamic systems from noisy measurements, without prior knowledge of the noise characteristics. This paper explores its generalization capabilities in out-of-distribution scenarios, where the temporal dynamics of the test measurements differ from those encountered during training. Le Recursive KalmanNet, récemment introduit par les auteurs, est un réseau de neurones récurrent guidé par un filtre de Kalman, capable d'estimer les variables d'état et la covariance des erreurs des systèmes dynamiques stochastiques à partir de mesures bruitées, sans connaissance préalable des caractéristiques des bruits. Cet article explore ses capacités de généralisation dans des scénarios hors distribution, où les dynamiques temporelles des mesures de test diffèrent de celles rencontrées à l'entraînement.

We perform a consistency check of DESI DR2 BAO constraints ($D_M/r_d, D_H/r_d)$ by reconstructing the same quantities from DES supernovae (SNe) in bins with the same effective redshift $z_{\textrm{eff}} \in \{ 0.510, 0.706, 0.934 \}$ and a Planck $r_d$ prior. Through mock analysis we show that $D_M(z_{\rm eff})$ and $D_{H}(z_{\rm eff})$ can be locally reconstructed model agnostically from $Λ$CDM and extended models, but only if one employs frequentist methods; purely Bayesian reconstructions from Markov Chain Monte Carlo (MCMC) exhibit bias. We find that the ratio of the three $D_M/r_d$ values at different $z_{\textrm{eff}}$ are consistent with a horizontal, thus confirming that the distance duality relation holds up to calibration. However, the $D_H/r_d$ ratio shows a decreasing trend driven by the $z_{\textrm{eff}} = 0.934$ bin, the significance of which varies from $2.5 σ$ with Bayesian methods down to $1.4 σ$ with frequentist methods. We show that replacing DES with DES-Dovekie SNe reduces the significance to $1.7 σ$ and $1.2 σ$ in Bayesian and frequentist approaches, respectively. We conclude that distances reconstructed from SNe show good agreement with DESI BAO distances acr

Dark Energy Survey five-year supernovae data (DES 5YR SNe) in conjunction with Planck CMB and Dark Energy Spectroscopic Instrument (DESI) BAO data has detected a strong dynamical dark energy (DE) deviation from the $Λ$CDM model.Here we shift the focus of DES data to the pressureless matter sector in the $Λ$CDM model by studying the matter density parameter $Ω_m$. Employing primarily frequentist profile likelihoods, supported by complementary Bayesian methods, we demonstrate that $Ω_m$ increases with effective redshift in the DES data up to a point that there is a $2.5 σ$ discrepancy with Planck. We relax the traditional $Ω_m \leq 1$ prior to demonstrate negative DE densities $Ω_m > 1$ at the highest effective redshift probed. Nevertheless, the largest discrepancy with Planck occurs for profile likelihoods and posteriors peaked at $Ω_m < 1$ in the traditional $Λ$CDM regime. Our findings corroborate earlier observations in Pantheon and Pantheon+ datasets with an independent SNe dataset with a higher effective redshift. In an appendix, we confirm that curvature $Ω_k$ decreases with effective redshift disfavouring a flat Universe in higher redshift DES SNe at $> 3 σ$. Our choi

We analyze the Dark Energy Survey (DES) Year 3 data using predictions from the Effective Field Theory of Large-Scale Structure (EFTofLSS). Specifically, we fit three two-point observables (3$\times$2pt), galaxy clustering, galaxy-galaxy lensing, and cosmic shear, using the one-loop expressions for the projected angular correlation functions. We validate our pipeline against numerical simulations and we check for several internal consistencies before applying it to the observational data. Fixing the spectral tilt and the baryons abundance, we measure $S_8=0.833\pm 0.032$, $Ω_m = 0.272\pm 0.022$, and $h = 0.773\pm 0.049$, to about $3.8\%$, $8.1\%$, and $6.3\%$, at $68\%$CL, respectively. Our results are consistent at the $\sim 1.5-2σ$ level with those from Planck and the BOSS full-shape analyses, as well as with those from DES collaboration 3$\times$2pt analysis combined with a Big-Bang Nucleosynthesis prior and a Planck prior on $n_s$. The shift in the posterior compared to DES collaboration results highlights the impact of modeling, scale cuts, and choice of prior. The theory code and likelihood used for our analyses, \texttt{PyFowl}, is made publicly available.

The Dark Energy Survey (DES) recently released the final results of its two principal probes of the expansion history: Type Ia Supernovae (SNe) and Baryonic Acoustic Oscillations (BAO). We explore the cosmological implications of these data in combination with external Cosmic Microwave Background (CMB), Big Bang Nucleosynthesis (BBN), and age-of-the-Universe information. The BAO measurement, $\sim2σ$ away from Planck's $Λ$CDM predictions, pushes for low values of $Ω_{\rm m}$ compared to Planck, in contrast to SN which prefers a higher value. We identify several tensions among datasets in the $Λ$CDM model that cannot be resolved by including either curvature or a constant dark energy equation of state. By combining BAO+SN+CMB despite these mild tensions, we obtain $Ω_k$=$-5.5^{+4.6}_{-4.2}\times10^{-3}$ in $kΛ$CDM, and $w=-0.948^{+0.028}_{-0.027}$ in $w$CDM. In $w$CDM, BAO and SN push again in different directions of parameter space, favoring, respectively $w<-1$ and $w>-1$. If we open the parameter space to $w_0w_a$CDM, all the datasets are mutually more compatible, and we find concordance in the $w_0>-1,w_a<0$ quadrant, with BAO pushing for $w_a<0$ and SN for $[w_0&

We present a novel approach for creating science-ready catalogs through a software infrastructure developed for the Dark Energy Survey (DES). We integrate the data products released by the DES Data Management and additional products created by the DES collaboration in an environment known as DES Science Portal. Each step involved in the creation of a science-ready catalog is recorded in a relational database and can be recovered at any time. We describe how the DES Science Portal automates the creation and characterization of lightweight catalogs for DES Year 1 Annual Release, and show its flexibility in creating multiple catalogs with different inputs and configurations. Finally, we discuss the advantages of this infrastructure for large surveys such as DES and the Large Synoptic Survey Telescope. The capability of creating science-ready catalogs efficiently and with full control of the inputs and configurations used is an important asset for supporting science analysis using data from large astronomical surveys.

Cosmic shear, galaxy clustering, and the abundance of massive halos each probe the large-scale structure of the Universe in complementary ways. We present cosmological constraints from the joint analysis of the three probes, building on the latest analyses of the lensing-informed abundance of clusters identified by the South Pole Telescope (SPT) and of the auto- and cross-correlation of galaxy position and weak lensing measurements (3$\times$2pt) in the Dark Energy Survey (DES). We consider the cosmological correlation between the different tracers and we account for the systematic uncertainties that are shared between the large-scale lensing correlation functions and the small-scale lensing-based cluster mass calibration. Marginalized over the remaining $Λ$ cold dark matter ($Λ$CDM) parameters (including the sum of neutrino masses) and 52 astrophysical modeling parameters, we measure $Ω_\mathrm{m}=0.300\pm0.017$ and $σ_8=0.797\pm0.026$. Compared to constraints from Planck primary cosmic microwave background (CMB) anisotropies, our constraints are only 15% wider with a probability to exceed of 0.22 ($1.2σ$) for the two-parameter difference. We further obtain $S_8\equivσ_8(Ω_\mathrm

Amateur and professional astronomers can easily capture a large number of deep sky images with recent smart telescopes. However, afterwards verification is still required to check whether the celestial objects targeted are actually visible in the images produced. Depending on the magnitude of the targets, the observation conditions and the time during which the data is captured, it is possible that only stars are present in the images. In this study, we propose an approach based on explainable Artificial Intelligence to automatically detect the presence and position of captured objects. -- -- Grâce à l'apport des télescopes automatisés grand public, les astronomes amateurs et professionnels peuvent capturer facilement une grande quantité d'images du ciel profond (comme par exemple les galaxies, nébuleuses, ou amas globulaires). Néanmoins, une vérification reste nécessaire à postériori pour vérifier si les objets célestes visés sont effectivement visibles dans les images produites: cela dépend notamment de la magnitude des cibles, des conditions d'observation mais aussi de la durée pendant laquelle les données sont capturées. Dans cette étude, nous proposons une approche basée sur l

Sujets qui sont plus particulierement abordes dans ce cours: 1. Elements de cosmologie, l'Univers homogene Les principes cosmologiques et leurs verifications observationnelles Histoire thermique de l'Univers Inflation, motivations et principe de base 2. Elements de cosmologie, l'Univers inhomogene La croissance des fluctuations Pourquoi un modele avec de la Matiere Noire Froide ? Evidences de l'existence de matiere noire 3. La dynamique gravitationnelle, les theories lineaires L'approximation Newtonnienne avec un seul flot Description Eulerienne ou description Lagrangienne Vers la dynamique non-lineaire: l'effondrement spherique 4. Le regime quasilineaire Effet du couplage de mode: la skewness La hierarchie des correlations en regimes quasi-lineaire Les termes sous-dominants du developpement perturbatif 5. Application aux proprietes statistiques des champs de distorsions gravitationnelles La relation entre convergence locale et densite projetee Variance et skewness de la convergence locale 6. Vers le regime fortement non-lineaire Les solutions auto-similaires et les modeles hierarchiques Distribution de matiere et distribution de lumiere

Macular Holes, Central serous retinopathy and Diabetic Retinopathy are one of the most widespread maladies of the eyes responsible for either partial or complete vision loss, thus making it clear that early detection of the mentioned defects is detrimental for the well-being of the patient. This study intends to introduce the application of Vision Transformer and Support Vector Machine based hybrid architecture (ViT-SVM) and analyse its performance to classify the optical coherence topography (OCT) Scans with the intention to automate the early detection of these retinal defects.

The paper describes a new method for the identification of the flow stress curves of anisotropic sheet metals using a hydraulic bulge tests through circular and elliptical dies. This method is based on analytical model using the membrane equilibrium equation and experimental data involving the measurement of only polar deflection and applied hydraulic pressure. Four hydraulic bulge tests are used for the identification of flow stress parameters and anisotropy coefficients of Hill48 yield criterion. A sensitivity analysis of material parameters is carried out by FEA of hydraulic bulge tests. This identification procedure is applied on low carbon steel DC04 used for sheet metal forming. The obtained results are used for numerical simulation of plane tensile test to validation the proposed method. It is shown a good agreement between predicted and experimental results. -- Le papier présente une nouvelle méthode pour l'identification des lois de comportement des tôles minces anisotropes à partir des essais de gonflement hydraulique en utilisant les essais à matrices circulaires et elliptiques. Cette méthode est basée sur un modèle analytique utilisant la théorie des membranes et des me

Many complex systems are modeled through complex networks whose analysis reveals typical topological properties. Amongst those, the community structure is one of the most studied. Many methods are proposed to detect communities, not only in plain, but also in attributed, directed or even dynamic networks. A community structure takes the form of a partition of the node set, which must then be characterized relatively to the properties of the studied system. We propose a method to support such a characterization task. We define a sequence-based representation of networks, combining temporal information, topological measures, and nodal attributes. We then characterize communities using the most representative emerging sequential patterns of its nodes. This also allows detecting unusual behavior in a community. We describe an empirical study of a network of scientific collaborations.---De nombreux systèmes complexes sont étudiés via l'analyse de réseaux dits complexes ayant des propriétés topologiques typiques. Parmi cellesci, les structures de communautés sont particulièrement étudiées. De nombreuses méthodes permettent de les détecter, y compris dans des réseaux contenant des attribu

We use the small scales of the Dark Energy Survey (DES) Year-3 cosmic shear measurements, which are excluded from the DES Year-3 cosmological analysis, to constrain the baryonic feedback. To model the baryonic feedback, we adopt a baryonic correction model and use the numerical package \texttt{Baccoemu} to accelerate the evaluation of the baryonic nonlinear matter power spectrum. We design our analysis pipeline to focus on the constraints of the baryonic suppression effects, utilizing the implication given by a principal component analysis on the Fisher forecasts. Our constraint on the baryonic effects can then be used to better model and ameliorate the effects of baryons in producing cosmological constraints from the next generation large-scale structure surveys. We detect the baryonic suppression on the cosmic shear measurements with a $\sim 2 σ$ significance. The characteristic halo mass for which half of the gas is ejected by baryonic feedback is constrained to be $M_c > 10^{13.2} h^{-1} M_{\odot}$ (95\% C.L.). The best-fit baryonic suppression is $\sim 5\%$ at $k=1.0 {\rm Mpc}\ h^{-1}$ and $\sim 15\%$ at $k=5.0 {\rm Mpc} \ h^{-1}$. Our findings are robust with respect to th

We present deep $g$- and $r$-band Magellan/Megacam photometry of two dwarf galaxy candidates discovered in the Dark Energy Survey (DES), Grus I and Indus II (DES J2038-4609). For the case of Grus I, we resolved the main sequence turn-off (MSTO) and $\sim 2$ mags below it. The MSTO can be seen at $g_0\sim 24$ with a photometric uncertainty of $0.03$ mag. We show Grus I to be consistent with an old, metal-poor ($\sim 13.3$ Gyr, [Fe/H]$\sim-1.9$) dwarf galaxy. We derive updated distance and structural parameters for Grus I using this deep, uniform, wide-field data set. We find an azimuthally averaged half-light radius more than two times larger ($\sim 151^{+21}_{-31}$ pc; $\sim 4.^{\prime} 16^{+0.54}_{-0.74}$) and an absolute $V$-band magnitude $\sim-4.1$ that is $\sim 1$ magnitude brighter than previous studies. We obtain updated distance, ellipticity, and centroid parameters which are in agreement with other studies within uncertainties. Although our photometry of Indus II is $\sim 2-3$ magnitudes deeper than the DES Y1 Public release, we find no coherent stellar population at its reported location. The original detection was located in an incomplete region of sky in the DES Y2Q1 da

Étienne Bézout, member of the Académie Royale des Sciences, have to study some works and books sended at the Académy. In this article, we will look at this responsibility for Navy, before and after 1764, which is the year of Bézout's nomination at the charge of Examinateur des Gardes du Pavillon et de la Marine. Each year he must go to Brest, Rochefort and Toulon harbours to examine the Gardes de la Marine. This give to him titles and qualifications as expert in sailing. We will see his participation at an Academy polemic : Blondeau versus Bouguer/Lacaille on a navigation book. Almost in the same time, Étienne Bézout will be member of the Académie de Marine de Brest in 1769. We will see his work in this last Academy. At last, we will study his Traité de navigation, written in 1769 and we will compare to Bouguer's Navigation book.

As the statistical power of galaxy weak lensing reaches percent level precision, large, realistic and robust simulations are required to calibrate observational systematics, especially given the increased importance of object blending as survey depths increase. To capture the coupled effects of blending in both shear and photometric redshift calibration, we define the effective redshift distribution for lensing, $n_γ(z)$, and describe how to estimate it using image simulations. We use an extensive suite of tailored image simulations to characterize the performance of the shear estimation pipeline applied to the Dark Energy Survey (DES) Year 3 dataset. We describe the multi-band, multi-epoch simulations, and demonstrate their high level of realism through comparisons to the real DES data. We isolate the effects that generate shear calibration biases by running variations on our fiducial simulation, and find that blending-related effects are the dominant contribution to the mean multiplicative bias of approximately $-2\%$. By generating simulations with input shear signals that vary with redshift, we calibrate biases in our estimation of the effective redshfit distribution, and demon

We present cosmology results combining galaxy clustering and weak gravitational lensing measured in the full six years (Y6) of observations by the Dark Energy Survey (DES) covering $\sim$5000 deg$^2$. We perform a large-scale structure analysis using three two-point correlation functions (3$\times$2pt): (i) cosmic shear from 140 million source galaxy shapes, (ii) galaxy clustering of 9 million lens galaxy positions, and (iii) galaxy-galaxy lensing from their cross-correlation. We model the data in flat $Λ$CDM and $w$CDM cosmologies. The combined analysis yields $S_8\equiv σ_8 (Ω_{\rm m}/0.3)^{0.5} = 0.789^{+0.012}_{-0.012}$ and matter density $Ω_{\rm m} = 0.333^{+0.023}_{-0.028}$ in $Λ$CDM (68\% CL), where $σ_8$ is the clustering amplitude. These constraints show a (full-space) parameter difference of 1.8$σ$ from a combination of cosmic microwave background (CMB) primary anisotropy datasets from Planck 2018, ACT-DR6, and SPT-3G DR1. Projected only into $S_8$ the difference is $2.6σ$. In $w$CDM the Y6 3$\times$2pt results yield $S_8 = 0.782^{+0.021}_{-0.020}$, $Ω_{\rm m} = 0.325^{+0.032}_{-0.035}$, and dark energy equation-of-state parameter $w = -1.12^{+0.26}_{-0.20}$. For the firs

We present cosmological constraints from the sample of Type Ia supernovae (SN Ia) discovered during the full five years of the Dark Energy Survey (DES) Supernova Program. In contrast to most previous cosmological samples, in which SN are classified based on their spectra, we classify the DES SNe using a machine learning algorithm applied to their light curves in four photometric bands. Spectroscopic redshifts are acquired from a dedicated follow-up survey of the host galaxies. After accounting for the likelihood of each SN being a SN Ia, we find 1635 DES SNe in the redshift range $0.10<z<1.13$ that pass quality selection criteria sufficient to constrain cosmological parameters. This quintuples the number of high-quality $z>0.5$ SNe compared to the previous leading compilation of Pantheon+, and results in the tightest cosmological constraints achieved by any SN data set to date. To derive cosmological constraints we combine the DES supernova data with a high-quality external low-redshift sample consisting of 194 SNe Ia spanning $0.025<z<0.10$. Using SN data alone and including systematic uncertainties we find $Ω_{\rm M}=0.352\pm 0.017$ in flat $Λ$CDM. Supernova data a

This paper presents a review of methods for collecting and analysing data on complex activities. Starting with methods developed for design, we examine the possibility to transpose them to other complex activities, especially activities referring to sensorial expertise. Résumé Ce texte présente une revue de méthodes pour recueillir et analyser des données sur des actvités complexes. A partir de méthodes développées pour des actvités de conception, nous examinons la possibilité de les transposer à d'autres actvités complexes, notamment des actvités faisant à appel à des expertises sensorielles.