Search results for "SPECTRA"
showing 10 items of 3542 documents
DeepIndices : Une nouvelle approche des indices de télédétection basée sur l'optimisation et l'approximation de fonctions par DeepLearning. Applicati…
2021
National audience; L'une des avancées les plus importantes dans le domaine de l'observation de la terre est la découverte des indices spectraux, ils ont notamment prouvé leur efficacité dans la caractérisation des surfaces agricoles, mais ils sont généralement définis de manière empirique. Cette étude basée sur l'intelligence artificielle et le traitement du signal, propose une méthode pour trouver un indice optimal. Et porte sur l'analyse d'images issues d'une caméra multi-spectrale, utilisée dans un contexte agricole pour l'acquisition en champ proche de végétation. À partir de six bandes spectrales, cinq modèles ont été testés et déployés dans un framework d'apprentissage profond. Les pe…
A case study of a precision fertilizer application task generation for wheat based on classified hyperspectral data from UAV combined with farm histo…
2013
Different remote sensing methods for detecting variations in agricultural fields have been studied in last two decades. There are already existing systems for planning and applying e.g. nitrogen fertilizers to the cereal crop fields. However, there are disadvantages such as high costs, adaptability, reliability, resolution aspects and final products dissemination. With an unmanned aerial vehicle (UAV) based airborne methods, data collection can be performed cost-efficiently with desired spatial and temporal resolutions, below clouds and under diverse weather conditions. A new Fabry-Perot interferometer based hyperspectral imaging technology implemented in an UAV has been introduced. In this…
Nuclear effects in neutrino-nucleus interactions: the role of spectral functions
2019
En esta tesis hemos estudiado la interacción neutrino-núcleo, en el régimen cuasielástico, haciendo un especial énfasis en la importancia de las correcciones nucleares. Motivación En el estudio de la física de oscilaciones de neutrinos, los desafíos más importantes que se presentan en la actualidad son (i) medir el valor de la fase de la violación de la simetría CP y (ii) discernir entre jerarquía normal o invertida en el respeto de masas de los neutrinos. Los futuros experimentos diseñados para resolver estas (y otras) cuestiones, incluyendo posibles descubrimientos de Física más allá del Modelo Estándar, sobre todo DUNE y T2HK, contarán con una estadística muy alta, asi…
Quasi-periodic dipping in the ultraluminous X-ray source, NGC 247 ULX-1
2021
Most ultraluminous X-ray sources (ULXs) are believed to be stellar mass black holes or neutron stars accreting beyond the Eddington limit. Determining the nature of the compact object and the accretion mode from broadband spectroscopy is currently a challenge, but the observed timing properties provide insight into the compact object and details of the geometry and accretion processes. Here we report a timing analysis for an 800 ks XMM-Newton campaign on the supersoft ultraluminous X-ray source, NGC 247 ULX-1. Deep and frequent dips occur in the X-ray light curve, with the amplitude increasing with increasing energy band. Power spectra and coherence analysis reveals the dipping preferential…
Factorization of strongly (p,sigma)-continuous multilinear operators
2013
We introduce the new ideal of strongly-continuous linear operators in order to study the adjoints of the -absolutely continuous linear operators. Starting from this ideal we build a new multi-ideal by using the composition method. We prove the corresponding Pietsch domination theorem and we present a representation of this multi-ideal by a tensor norm. A factorization theorem characterizing the corresponding multi-ideal - which is also new for the linear case - is given. When applied to the case of the Cohen strongly -summing operators, this result gives also a new factorization theorem.
Operators which have a closed quasi-nilpotent part
2002
We find several conditions for the quasi-nilpotent part of a bounded operator acting on a Banach space to be closed. Most of these conditions are established for semi-Fredholm operators or, more generally, for operators which admit a generalized Kato decomposition. For these operators the property of having a closed quasi-nilpotent part is related to the so-called single valued extension property.
Weyl's theorem for perturbations of paranormal operators
2007
A bounded linear operator T ∈ L(X) on a Banach space X is said to satisfy "Weyl's theorem" if the complement in the spectrum of the Weyl spectrum is the set of all isolated points of the spectrum which are eigenvalues of finite multiplicity. In this paper we show that if T is a paranormal operator on a Hilbert space, then T + K satisfies Weyl's theorem for every algebraic operator K which commutes with T.
Refinements of PIP-Spaces
2009
We have seen in Section 1.5, that the compatibility relation underlying a pip-space may always be coarsened, but not refined in general. There is an exception, however, namely the case of a scale of Hilbert spaces and analogous structures. We shall describe it in this section.
Spectra and essential spectral radii of composition operators on weighted Banach spaces of analytic functions
2008
AbstractWe determine the spectra of composition operators acting on weighted Banach spaces Hv∞ of analytic functions on the unit disc defined for a radial weight v, when the symbol of the operator has a fixed point in the open unit disc. We also investigate in this case the growth rate of the Koenigs eigenfunction and its relation with the essential spectral radius of the composition operator.
Ultrarelativistic bound states in the spherical well
2016
We address an eigenvalue problem for the ultrarelativistic (Cauchy) operator $(-\Delta )^{1/2}$, whose action is restricted to functions that vanish beyond the interior of a unit sphere in three spatial dimensions. We provide high accuracy spectral datafor lowest eigenvalues and eigenfunctions of this infinite spherical well problem. Our focus is on radial and orbital shapes of eigenfunctions. The spectrum consists of an ordered set of strictly positive eigenvalues which naturally splits into non-overlapping, orbitally labelled $E_{(k,l)}$ series. For each orbital label $l=0,1,2,...$ the label $k =1,2,...$ enumerates consecutive $l$-th series eigenvalues. Each of them is $2l+1$-degenerate. …