Дисертації з теми "Spectral inversion"
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Orozco, M. Catalina (Maria Catalina). "Inversion Method for Spectral Analysis of Surface Waves (SASW)." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5124.
Повний текст джерелаSet, Sze Yun. "Dispersion compensation in high bit rate transmission systems using midspan spectral inversion." Thesis, University of Southampton, 1998. https://eprints.soton.ac.uk/394393/.
Повний текст джерелаDeng, Mo Ph D. Massachusetts Institute of Technology. "Deep learning with physical and power-spectral priors for robust image inversion." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127013.
Повний текст джерелаCataloged from the official PDF of thesis.
Includes bibliographical references (pages 169-182).
Computational imaging is the class of imaging systems that utilizes inverse algorithms to recover unknown objects of interest from physical measurements. Deep learning has been used in computational imaging, typically in the supervised mode and in an End-to-End fashion. However, treating the machine learning algorithm as a mere black-box is not the most efficient, as the measurement formation process (a.k.a. the forward operator), which depends on the optical apparatus, is known to us. Therefore, it is inefficient to let the neural network to explain, at least partly, the system physics. Also, some prior knowledge of the class of objects of interest can be leveraged to make the training more efficient. The main theme of this thesis is to design more efficient deep learning algorithms with the help of physical and power-spectral priors.
We first propose the learning to synthesize by DNN (LS-DNN) scheme, where we propose a dual-channel DNN architecture, each designated to low and high frequency band, respectively, to split, process, and subsequently, learns to recombine low and high frequencies for better inverse conversion. Results show that the LS-DNN scheme largely improves reconstruction quality in many applications, especially in the most severely ill-posed case. In this application, we have implicitly incorporated the system physics through data pre-processing; and the power-spectral prior through the design of the band-splitting configuration. We then propose to use the Phase Extraction Neural Networks (PhENN) trained with perceptual loss, that is based on extracted feature maps from pre-trained classification neural networks, to tackle the problem of low-light phase retrieval under low-light conditions.
This essentially transfer the knowledge, or features relevant to classifications, and thus corresponding to human perceptual quality, to the image-transformation network (such as PhENN). We find that the commonly defined perceptual loss need to be refined for the low-light applications, to avoid the strengthened "grid-like" artifacts and achieve superior reconstruction quality. Moreover, we investigate empirically the interplay between the physical and con-tent prior in using deep learning for computational imaging. More specifically, we investigate the effect of training examples to the learning of the underlying physical map and find that using training datasets with higher Shannon entropy is more beneficial to guide the training to correspond better to the system physics and thus the trained mode generalizes better to test examples disjoint from the training set.
Conversely, if more restricted examples are used as training examples, the training can be guided to undesirably "remember" to produce the ones similar as those in training, making the cross-domain generalization problematic. Next, we also propose to use deep learning to greatly accelerate the optical diffraction tomography algorithm. Unlike previous algorithms that involve iterative optimization algorithms, we present significant progresses towards 3D refractive index (RI) maps from a single-shot angle-multiplexing interferogram. Last but not least, we propose to use cascaded neural networks to incorporate the system physics directly into the machine learning algorithms, while leaving the trainable architectures to learn to function as the ideal Proximal mapping associated with the efficient regularization of the data. We show that this unrolled scheme significantly outperforms the End-to-End scheme, in low-light imaging applications.
by Mo Deng.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
Pappalardo, Cirino, Bernd Vollmer, and Ariane Lancon. "The star formation history of Virgo spiral galaxies. Combined spectral and photometric inversion." Phd thesis, Université de Strasbourg, 2010. http://tel.archives-ouvertes.fr/tel-00483128.
Повний текст джерелаPappalardo, Cirino. "The star formation history of Virgo spiral galaxies : combined spectral and photometric inversion." Strasbourg, 2010. https://publication-theses.unistra.fr/public/theses_doctorat/2010/PAPPALARDO_Cirino_2010.pdf.
Повний текст джерелаThis thesis investigates the influence of ram pressure stripping on the star formation history of cluster spiral galaxies. Ram pressure stripping is the hydrodynamical interaction between the interstellar medium (ISM) of a spiral galaxy that is moving inside the potential well of a cluster, and the intracluster medium (ICM). If the dynamical pressure exerted by the ICM is larger than the restoring force due to the galactic potential, the galaxy loses gas from the outer disk. The Virgo cluster is an ideal laboratory to study environmental effects on galaxy evolution, because it is rich in spirals and dynamically young. From observations we know that the amount of atomic gas in Virgo spirals is less than that of galaxies in the field. In particular cluster spirals show truncated HI disks (Giovanelli & Haynes 1983, Cayatte et al. 1990). For those galaxies that also show a symmetrical stellar distribution, ram pressure stripping is the most probably origin of the gas-disk truncation
OLIVEIRA, OTAVIO KAMINSKI DE. "INVERSION OF NONLINEAR PERTURBATIONS OF THE LAPLACIAN IN GENERAL DOMAINS WITH FINITE SPECTRAL INTERACTION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=27930@1.
Повний текст джерелаCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
Consideramos a análise numérica de perturbações não lineares do Laplaciano definido em regiões limitadas tratáveis pelo Método de Elementos Finitos. Supomos que as não linearidades interagem com k autovalores do Laplaciano livre. Apresentamos uma redução do problema à inversão de uma função de k variáveis e delineamos uma técnica para tal. O texto é uma extensão dos trabalhos de Cal Neto, Malta, Saldanha e Tomei.
We consider the numerical analysis of nonlinear perturbations of the Laplacian defined in limited regions amenable to the Finite Element Method. The nonlinearities are supposed to interact only with k eigenvalues of the free Laplacian. We present a reduction of the problem to the inversion of a function of k variables and indicate a technique to do so. The text extends the works by Cal Neto, Malta, Saldanha and Tomei.
Reine, Carl Andrew. "A robust prestack Q-Inversion in the T-p Domain using variable-window spectral estimates." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511145.
Повний текст джерелаFernandez, Cesar Aaron Moya. "Two alternative inversion techniques for the determination of seismic site response and propagation-path velocity structure : spectral inversion with reference events and neural networks." 京都大学 (Kyoto University), 2004. http://hdl.handle.net/2433/147831.
Повний текст джерелаMarkusson, Ola. "Model and System Inversion with Applications in Nonlinear System Identification and Control." Doctoral thesis, KTH, Signals, Sensors and Systems, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3287.
Повний текст джерелаGhorbani, Ahmad. "Contribution au développement de la résistivité complexe et à ses applications en environnement." Paris 6, 2007. http://www.theses.fr/2007PA066607.
Повний текст джерелаCureton, Geoffrey Patrick. "Retrieval of nonlinear spectral information from ocean sunglint." Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/1549.
Повний текст джерелаLevy, Robert Carroll. "Retrieval of troposheric aerosol properties over land from inversion of visible and near-infrared spectral reflectance application over Maryland /." College Park, Md. : University of Maryland, 2007. http://hdl.handle.net/1903/6822.
Повний текст джерелаThesis research directed by: Atmospheric and Oceanic Sciences. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Qin, Yilong. "SPICE benchmark pour méthodes tomographiques globaux et test des modèles tomographiques globaux." Paris, Institut de physique du globe, 2007. http://www.theses.fr/2007GLOB0016.
Повний текст джерелаOver the last two decades, a lot of global-scale or regional-scale seismic models of the Earth's interiors have been constructed from different types of seismological measurements (body-wave traveltime, surface-wave phase velocity or full waveforms) and with different theoretical assumptions of seismic wave propagation (ray theory, Born approximation or wave equation) and with different inversion techniques (iterative least-square inversion, Monte-Carlo or Neighborhood algorithm) and different parameterizations (spherical harmonics up to a variable degree or blocks or adaptive triangles). Generally these different tomographic methods generate different tomographic models. To calibrate these different tomographic methods and test these different tomographic models, we decided to perform a global-scale benchmark for seismic tomography and test different global-scale tomographic models. So this thesis is divided into two parts
Benzerhouni, Kaddour. "Spectroscopie d'absorption de l'ammoniac et étude du laser (¹⁵NH₃+ N₂) à inversion de population." Paris 11, 1988. http://www.theses.fr/1988PA112097.
Повний текст джерелаThis work is a study of the ammonia molecule under its two isotopic species ¹⁴ NH₃ and ¹⁵NH₃. The two following topics are developed:On one hand, the spectroscopic aspect of the molecule is studied related to the spectral profile of the absorption tine. On the other hand, we perform ammonia laser working in mid infrared by optical pumping with a CO2 laser. In chapter I all spectroscopic data about this ammonia molecule are reported, especially the -√2 absorption band in the 10,5 µm spectral range. This band gives rise to a lot of quasi coïncidences with the emission lines of the C02 for the two isotopic species ¹⁴ NH₃ and ¹⁵NH₃. In chapter ll, the profile of the absorption lines is studied. The intensities and line-width of some tines have been measured using a diode laser spectrometer. The way to determine collisional line-width is described. Several methods are used to determine intensities. Advantages and disadvantages of each method are discussed. In chapter Ill, ail previous works about the ammonia laser are recalled, especially the off-resonant optical pumping giving rise to the powerful Raman laser. We report the work made with this "Raman laser" at 12,08 μm, in order to study the absorption profile of the sP(7,0) line of ammonia. The results obtained with ¹⁴ NH₃ specie self-broadened, or with buffer gases, N₂ or He, are reported and discussed. In chapter IV, we describe our work about the resonant optical pumping on ¹⁵NH₃ in a ring configuration. The study, realization and optimization for the population inversion laser (¹⁵NH₃+ N₂) giving a laser line at 11,76 μm, is developed. The main experimental results about the properties of this laser are reported. A rate equation model is established for the small signal gain. An analysis of the gain according to the different parameters of the laser gives a good comparison with experimental results
Boumaaza, Bouharket. "3D seismic attributes analysis and inversions for prospect evaluation and characterization of Cherokee sandstone reservoir in the Wierman field, Ness County, Kansas." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/35510.
Повний текст джерелаDepartment of Geology
Abdelmoneam Raef
Matthew W. Totten
This work focuses on the use of advanced seismically driven technologies to estimate the distribution of key reservoir properties which mainly includes porosity and hydrocarbon reservoir pay. These reservoir properties were estimated by using a multitude of seismic attributes derived from post-stack high resolution inversions, spectral imaging and volumetric curvature. A pay model of the reservoir in the Wierman field in Ness County, Kansas is proposed. The proposed geological model is validated based on comparison with findings of one blind well. The model will be useful in determining future drilling prospects, which should improve the drilling success over previous efforts, which resulted in only few of the 14 wells in the area being productive. The rock properties that were modeled were porosity and Gamma ray. Water saturation and permeability were considered, but the data needed were not available. Sequential geological modeling approach uses multiple seismic attributes as a building block to estimate in a sequential manner dependent petrophysical properties such as gamma ray, and porosity. The sequential modelling first determines the reservoir property that has the ability to be the primary property controlling most of the other subsequent reservoir properties. In this study, the gamma ray was chosen as the primary reservoir property. Hence, the first geologic model built using neural networks was a volume of gamma ray constrained by all the available seismic attributes. The geological modeling included post-stack seismic data and the five wells with available well logs. The post-stack seismic data was enhanced by spectral whitening to gain as much resolution as possible. Volumetric curvature was then calculated to determine where major faults were located. Several inversions for acoustic impedance were then applied to the post-stack seismic data to gain as much information as possible about the acoustic impedance. Spectral attributes were also extracted from the post-stack seismic data. After the most appropriate gamma ray and porosity models were chosen, pay zone maps were constructed, which were based on the overlap of a certain range of gamma ray values with a certain range of porosity values. These pay zone maps coupled with the porosity and gamma ray models explain the performance of previously drilled wells.
Traforti, Anna. "Reactivated fault zones: kinematic complexity and fault rock spectral characterization." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3421819.
Повний текст джерелаNel presente lavoro sono stati investigati tre fattori che contribuiscono alla definizione della complessità delle zone di faglia riattivate: i) la ricostruzione dell’evoluzione tettonica polifasica accomodata da zone di faglia che interessano litologie eterogenee; ii) la stima del grado di anisotropia meccanica associata alla presenza di discontinuità planari pre-esistenti (i.e., foliazioni metamorfiche e faglie), il quale influenza i meccanismi di riattivazione lungo tali piani; iii) la caratterizzazione spettrale delle rocce di faglia, finalizzata all’ identificazione della distribuzione delle zone di danno e di core tramite tecniche di remote sensing, con particolare riguardo a zone di faglie mature aventi un’architettura complessa. Al fine di dare un nuovo contributo alla comprensione dei fattori che definiscono le complessità insite nelle zone di faglia riattivate, sono state applicate diverse metodologie che comprendono: i) l’inversione del campo di paleostress, applicata considerando il comportamento meccanico dei domini litologici interessati da ogni differente zona di faglia; ii) l’approccio statistico di tipo ‘bootstrapping’ applicato al fine di valutare l’omogeneità tra i tensori di stress ricavati e di identificare possibili perturbazioni locali del campo di paleostress; iii) la ‘normalised slip tendensy analysis’ che, integrata alla ricostruzione del campo di paleostress e ad una caratterizzazione di tipo micro- e meso-strutturale, permette di stimare quantitativamente le proprietà meccaniche di discontinuità planari pre-esistenti; iv) l’analisi delle bande di assorbimento osservate negli spettri di riflettenza di diverse rocce di faglia, al fine di evidenziare il rapporto esistente tra le variazioni osservate nei parametri spettrali e i processi di comminuzione dovuti all’evolversi della zona di faglia stessa. I principali risultati di questo lavoro evidenziano come: i) tettoniche polifasiche che si sviluppano in domini rocciosi altamente eterogenei possono essere efficacemente ricostruite applicando in maniera integrata l’inversione del campo di paleostress e l’analisi statistica di tipo ‘bootstrapping’; ii) la ‘normalised slip tendency analysis’ permette di investigare la debolezza di anisotropie pre-esistenti a scala regionale (104-103 m); iii) la riduzione granulometrica connessa ai processi di comminuzione dovuti all’evolversi di una zona di faglia in rocce incassanti omogenee dal punto di vista mineralogico (carbonati in questo caso) influenza la firma spettrale delle rocce di faglia, le cui bande di assorbimento hanno caratteristiche che variano sistematicamente con la diminuzione della granulometria; iv) di conseguenza, l’analisi in remoto, basata sugli effetti della comminuzione sulle firme spettrali delle rocce di faglia, dimostra un buon potenziale nell’identificazione della distribuzione spaziale delle zone di danno e di core di una faglia in rocce incassanti omogenee dal punto di vista mineralogico.
Nassif, Moussa Daou David. "Caractérisation des aérosols par inversion des données combinées des photomètres et lidars au sol." Thèse, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/6058.
Повний текст джерелаEremenko, Maxim. "Inversion des spectres infrarouges à haute résolution spectrale enregistrés en absorption à partir de ballons stratosphériques : ajustement global de grands domaines spectraux : inversion multi-paramètres (espèces moléculaires)." Paris 6, 2003. http://www.theses.fr/2003PA066109.
Повний текст джерелаBing, Zhou. "Crosshole resistivity and acoustic velocity imaging : S.5-D helmholtz equation modeling and inversion /." Title page, contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phb613.pdf.
Повний текст джерелаGao, Guochao. "Contribution to seismic modeling and imaging in the presence of reflector roughness." Thesis, Ecole centrale de Marseille, 2020. http://www.theses.fr/2020ECDM0010.
Повний текст джерелаDue to various geological processes and crustal movements, rough interfaces widely exist within the Earth. The rough interface can strongly affect seismic wave propagation, manifested as changes in the amplitude, phase, scattering angle, frequency content, and even the wave-type conversion. Inevitably, the quality of seismic imaging or inversion is also greatly influenced. Despite the numerous works devoted to the interaction of waves with rough interfaces, this interaction remains to be better understood, as it is still quite challenging to model the seismic wave propagation and to properly reconstruct the subsurface. The thesis investigates the effect of rough interfaces on seismic wave modeling and imaging, and explores the potential of an electromagnetic method to remove this effect and to better image the subsurface.We use a spectral-element method, and more specifically the code SPECFEM2D, for modeling acoustic wave propagation in the time domain. First, we consider a sinusoidal grating and illustrate numerically the consequences of the grating equation on the temporal signals. Then, using f-k analysis, we show the location of the different diffraction orders in the frequency-wavenumber domain. After a sensitivity analysis, we select an appropriate configuration that allows for the separation of diffraction orders from a shot gather. Last, both roughness height and correlation length are shown to obviously influence the appearance of the diffracted wavefield. However, the correlation length has less effect on the energy of the diffracted waves than the interface roughness.We adopt a full-waveform inversion (FWI) scheme based on the software package DENISE to study the influence of different roughness heights and correlation lengths on seismic imaging results. When the roughness height increases up to the dominant wavelength or is greater, the random noise dominates in the seismic data, and the FWI results significantly deteriorate, especially for the reconstruction of a horizontal reflector located below the rough interface. In contrast, the correlation length has a much smaller effect on both random noise and quality of the inverted results than the roughness height. As shown here, the interface roughness has a major impact on both seismic wave propagation and imaging. When a rough interface is expected to be present in the subsurface, its effect should be critically considered in FWI, in order to properly reconstruct reflectors possibly located below, and then to properly interpret images of the subsurface. In this context, we perform some preliminary tests on the use of a selective extinction method to remove the impact of the roughness on the wavefields. The results are promising and show the potential of the method for better imaging. In addition, the standard deviation of the amplitude of the processed data may be used to evaluate the characteristics of the rough interface, which is also of interest for geophysicists and geologists
Benavides, Iglesias Alfonso. "Experimental time-domain controlled source electromagnetic induction for highly conductive targets detection and discrimination." Texas A&M University, 2003. http://hdl.handle.net/1969.1/5810.
Повний текст джерелаPike, Brian Henry. "Functionalism, qualia and spectrum inversion." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293880.
Повний текст джерелаPeiponen, K. E. (Kai-Erik). "Optical spectra analysis of turbid liquids." Doctoral thesis, University of Oulu, 2009. http://urn.fi/urn:isbn:9789514291685.
Повний текст джерелаMahieux, Arnaud. "Inversion des spectres infrarouges enregistrés par l'instrument SOIR à bord de la sonde Venus Express." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209957.
Повний текст джерелаSOIR, acronyme de Solar Occultation in the InfraRed, est un instrument russo-franco-belge embarqué à bord de la mission Venus Express de l'Agence Spatiale Européenne. Il utilise un réseau à échelle comme élément diffractant. La plage de nombre d'onde mesurable par SOIR s'étend de 2200 cm-1 à 4400 cm-1, ou 4.3 µm à 2.2 µm en longueur d'onde. Les ordres de diffraction utiles varient de 101 à 194. Un filtre acousto-optique - AOTF - est utilisé comme passe-bande pour sélectionner les ordres de diffraction. La résolution de l'instrument varie de 0.13 à 0.24 cm-1.
Du fait d'un temps de développement raccourci, presque toutes les calibrations de l'instrument ont dû être réalisées en vol. Elles comprennent les calibrations relatives au réseau à échelle (angle exact de Blaze et fonction de Blaze), au détecteur (non-uniformité pixel à pixel, courbe de sensibilité spectrale, relation entre les pixels et les nombres d'onde, résolution de l'instrument, intervalle d'échantillonnage spectral, rapport signal sur bruit, background thermique) et à l'AOTF (relation entre la radio-fréquence d'excitation de l'AOTF et les nombres d'onde, fonction de transfert de l'AOTF). L'approche et la réalisation de ces différentes calibrations sont présentées dans le présent travail. Les caractéristiques de l'instrument y sont également décrites.
Un algorithme d'inversion spectrale a été développé pour le cas spécifique de SOIR. Tenant compte du mode de mesure, l'occultation solaire, la méthode de la pelure d'oignons a été implémentée dans un algorithme dit de l'Estimation Optimale. Cette méthode permet d'inverser l'ensemble des mesures spectrales en une fois, et également d'en tirer d'autres informations, comme l'amélioration de certaines caractéristiques instrumentales. Les paramètres qui sont ajustés au sein de l'algorithme sont la densité de la ou des espèces absorbant dans la région spectrale concernée, la température, les paramètres de la ligne de base, qui permettent de déterminer les caractéristiques des aérosols, le déplacement Doppler des raies qui trouve principalement son origine dans la vitesse de déplacement du satellite, et l'amélioration de certaines calibrations. Une étude de sensibilité des différents paramètres de l'algorithme est également présentée, ainsi qu'une évaluation des erreurs instrumentales systématiques.
Dans l'ensemble des spectres enregistrés durant les 4 premières années de la mission, des profils verticaux de CO2, CO, H2O, HDO, SO2, H2SO4, HCl et HF ont été obtenus. Des valeurs limites de densité de OCS, H2CO, O3 et CH4 ont également été calculées.
Les résultats concernant le dioxyde de carbone sont développés dans le texte. Des profils verticaux de CO2 s'étendant de 70 km à 180 km d'altitude sont analysés en profondeur. Ils sont comparés aux profils dits hydrostatiques, et des hypothèses quant à la dynamique agissant au niveau des deux terminateurs de Vénus sont formulées.
/
Venus, second planet of the solar system, is often seen as the sister planet of the Earth. In terms of size and mass, they are indeed very similar, but the Venus atmosphere is much thicker and active. The altitude region extending from 70 km to 180~km is studied in this thesis, namely the mesosphere and the lower thermosphere.
SOIR, which stands for Solar Occultation in the InfraRed, is a Russian / French / Belgian instrument flying on board of the Venus Express (VEX) spacecraft of the European Space Agency. The diffracting device of SOIR is an echelle grating. The wavenumber region studied ranges from 2200 cm-1 to 4400 cm-1, or 4.3 µm to 2.2 µm in wavelength. The diffraction orders used with SOIR vary from 101 to 194. To select the required echelle grating diffraction order, an Acousto-Optical Tunable Filter - AOTF - is located after the entrance slit of the instrument. The instrument resolution varies from 0.13 to 0.24 cm-1.
SOIR was developed in a very short time. Thus, virtually all the calibrations had to be made in-flight. These concern the echelle grating (exact Blaze angle computation, Blaze function), the detector (pixel-to-pixel non-uniformity, spectral sensitivity curve, pixel-to-wavenumber relationship, instrument resolution, spectral sampling interval, signal-to-noise ratio, thermal background) and the AOTF (wavenumber to AOTF frequency relation, AOTF transfer function). The procedure for and the computation of these calibrations are described in this work, as well as the instrument characteristics.
A spectral inversion algorithm was developed specifically for the SOIR measurement technique: the solar occultation. The onion peeling method is implemented using the Optimal Estimation Method. It allows the inversion of the spectral data in one go, and also the enhancement of some instrumental characteristics. The algorithm variables are the densities of the species absorbing in the diffraction order, the temperature of the atmosphere under study, the spectral background parameters, that allow the determination of the Venus aerosols characteristics, the Doppler shift (mainly linked to the shift induced by the satellite displacement), and the improvement of some instrumental calibrations. A sensitivity study on the algorithm parameters is also presented, and the instrumental systematic errors are investigated.
Vertical profiles of CO2, CO, H2O, HDO, SO2, H2SO4, HCl and HF are derived from the spectra measured during the first 4 mission years. Upper limits on OCS, H2CO, O3 and CH4 have also been calculated.
We focus on the carbon dioxide results in the present study. A selection of vertical profiles extending from 70 km to 180 km are analyzed in details. They are compared to the hydrostatic profiles, and propositions concerning the terminators' dynamics are formulated.
Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
吳子傑 and Tsz-kit Victor Ng. "Inversion of low energy electron diffraction IV spectra of reconstructed structure of SiC (0001)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31225007.
Повний текст джерелаNg, Tsz-kit Victor. "Inversion of low energy electron diffraction IV spectra of reconstructed structure of SiC (0001)." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23234283.
Повний текст джерелаNagayama, Taisuke. "A new inversion method for the spectroscopic analysis of image data." abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1433297.
Повний текст джерелаWilson, Adam. "Theory and methods of frequency-dependent AVO Inversion." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4740.
Повний текст джерелаFurtado, Neto Alexandre [UNESP]. "O potêncial de poço duplo e a molécula de amônia." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/91817.
Повний текст джерелаCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O foco deste trabalho é o espectro de inversão da molécula de amônia, resultado do fenômeno do tunelamento quântico. Para isso, usamos um modelo simpli cado, uni- dimensional, suscetível a uma análise teórica rigorosa usando a mecânica quântica não- relativística. Dentre as diversas funções hamiltonianas já estudadas para este modelo, zemos uma rápida apreciação dos trabalhos de Cohen, Dennison-Uhlenbeck, Manning, Merzbacher e Rosen-Morse. Para um estudo mais profundo, usamos o potencial do poço duplo nito que, posteriormente, descobrimos já fora analisado por Peacock-López. Re- zemos a análise deste potencial usando um caminho diferente do realizado por aquele autor. Analisamos os casos limites para este potencial e notamos que realmente, nesses regimes, ele tende para um poço nito único ou dois poços nitos separados. Então, de- senvolvemos um software grá co centrado no pacote MINUIT, desenvolvido pelo CERN, para analisar e ajustar os parâmetros aos dados experimentais da amônia e, ao nal, comparamos os resultados obtidos com aqueles encontrados na literatura. No ajuste dos parâmetros à amônia, houve uma melhoria acentuada quando passamos de uma fórmula mais simples da massa reduzida para outra mais so sticada. No caso especí co do po- tencial de Peacock-López, a comparação revela que os nossos resultados, de uma maneira geral, são mais precisos. Nossa análise se soma àquelas que contêm uma discussão quan- titativa do potencial de poço duplo. Como parte integrante deste trabalho, uma versão unidimensional simétrica do potencial de Morse foi exatamente resolvida em termos de funções de Kummer e um par de equações transcendentes para as autoenergias. A tentativa de ajustar este resultado à molécula de amônia, porém, mostrou que os padrões de poço duplo deste potencial...
The focus of this work is the inversion spectrum of the ammonia molecule, a result of the phenomenon of quantum tunneling. For this, we use a simpli ed, one-dimensional model, amenable to a rigorous theoretical analysis using the non-relativistic quantum me- chanics. Among the various Hamiltonian functions previously studied for this model, we made a quick appraisal of the work of Cohen, Dennison-Uhlenbeck, Manning, Merzbacher and Rosen-Morse. For a deeper study, we used the nite double-well potential which, as we later discovered, had been considered by Peacock-López. We redid the analysis of this potential using a di¤erent path made by that author. We analyze the limiting cases for this potential and actually noticed that in these schemes, it tends to one nite well or two separate nite wells. So, we developed a graphical software centered on the MINUIT pack- age, developed by CERN, to analyze and adjust the parameters to the experimental data of ammonia and at the end, we compared the results with those found in the literature. In setting the parameters of ammonia, there was a marked improvement when we move from a simpler formula for the reduced mass to a more sophisticated one. In the speci c case of the potential of Peacock-López, the comparison shows that our results, in general, are more accurate and precise. Our analysis adds to those that contain a quantitative discussion of the double-well potential. As part of this work, a symmetric one-dimensional version of the Morse potential is exactly solved in terms of the Kummer functions and a pair of transcendental equations for the eigenenergies. Attempting to adjust this result to the ammonia molecule, however, showed that the double-well patterns of this potential well are irreconcilable with the energy spectrum of ammonia: Close pairs separated by long intervals
Lachérade, Sophie. "Caractérisation des propriétés optiques des matériaux urbains à partir d'images de télédétection à très hautes résolutions spatiale et spectrale." Toulouse, ENSAE, 2006. http://www.theses.fr/2006ESAE0008.
Повний текст джерелаLiu, Qinya Stock J. M. "Spectral-element simulations of 3-D seismic wave propagation and applications to source and structural inversions /." Diss., Pasadena, Calif. : Caltech, 2006. http://resolver.caltech.edu/CaltechETD:etd-05262006-172954.
Повний текст джерелаRinkel, Jean-Marc. "Inverses et propriétés spectrales des matrices de Toeplitz à symbole singulier." Paris 11, 2001. http://www.theses.fr/2001PA112187.
Повний текст джерелаFiorucci, Irene <1980>. "Development of the optimal estimation method for inversion of stratospheric emission spectra and validation of HNO3 profiles." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2933/1/fiorucci_irene_tesi.pdf.
Повний текст джерелаFiorucci, Irene <1980>. "Development of the optimal estimation method for inversion of stratospheric emission spectra and validation of HNO3 profiles." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/2933/.
Повний текст джерелаUllah, Irfan. "Caracterização da subsuperfície rasa através da curva da razão espectral H/V e da inversão conjunta das curvas de dispersão e elipticidade." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/14/14132/tde-04062018-101840/.
Повний текст джерелаThe destruction caused by an earthquake at a site depends on many factors like source characteristics such as magnitude, epicentral distance from the site, depth of the source, and on the geological setting of the area. The destruction caused due to the geological setting of an area is termed as site effect. To model the site effect of an area is to determine the shaking level longevity and its displacement amplification. The elastic properties (shear and compressional wave velocities, density, thickness of soil layer, etc.) of the site are required to find out by employing various geophysical procedures. The knowledge of these elastic properties help in better designing the infrastructure, which reduces the chances of destruction caused by a local geological setting due to an earthquake occurrence. This procedure is widely termed as microzonation. The most important parameters for the microzonation are the thickness of soft sediments over the seismic bedrock and its shear wave velocity profile. These two parameters are properly characterized by employing various geophysical techniques like borehole measurement, seismic reflection and seismic refraction. The conventional geophysical methods bring some hindrance to the picture such as, the drilling of a borehole and artificial seismic sources deployment for the reflection and refraction survey, which are both expensive and time consuming, difficult or even in some case impossible to implement in urbanized environment, the investigation is depth limited to few tens of meter. The methods which replaced this conventional geophysical method from the last decades or so is the analysis of Earth vibration caused by the seismic noise which is produced by both natural and cultural sources. This ambient seismic noise can be recorded with less cost and effort with good lateral coverage. Various seismic noise techniques are employed for this job; however, the one which got the most attention in recent years is the horizontal over vertical spectral ratio (H/V) technique. The H/V spectral ratio curve is a fast easy and cheap tool for the near-subsurface characterization. There are various study performed on the topic which has tried to cover almost all the aspects and problems associated with the method. Here in this study, we try to detail the aspects of this technique, which are not been evaluated fully. The different modelling procedures presented to model and physically link the H/V curve with some physical phenomenon will be discussed and its numerical result with the experimental H/V curve will be compared for a borehole test site. The peak and the shape of the H/V curve will be modelled to find its peak frequency deviation from the shear wave resonance frequency by considering different wave-field around the peak. Similarly, the shape dominancy of the H/V curve linkage will be find out. The peak frequency of the H/V curve is used to estimate the thickness-frequency relation by regression analysis. Here we will show that the dispersion curve obtained from multi-channel analysis of surface waves (MASW) can be used to estimate the velocity at one meter and the shear wave velocity increase trend with depth. These values can be used to estimate the thickness frequency relation for an area and its result will be compared with the experimentally derived thickness-frequency relationship for the same area. The sensitivity of the H/V curve shape to the subsurface velocity structure will find out for two main modelling techniques (Rayleigh wave ellipticity and diffused field based H/V curve). The different parts of the H/V curve are inverted (back modelled) to find out the part of H/V curve which is carrying the most important information about the subsurface structure. The lesson learned from all this analysis will be applied to experimental data of three different sites. The Love waves might contaminate the result of the H/V curve. Two different techniques to remove their effects will be discussed. Then, the joint inversion result of the dispersion and this Love effect removed H/V for more precisely ellipticity curve is discussed. Some new aspects of the H/V curve technique are also discussed at the end.
Bezzeghoud, Mourad. "Inversion et analyse spectrale des ondes p : potentialite des donnees numeriques large bande : application a des seismes mediterraneens et chiliens." Paris 7, 1987. http://www.theses.fr/1987PA077249.
Повний текст джерелаBezzeghoud, Mourad. "Inversion et analyse spectrale des ondes P, potentialité des données numériques large bande application à des séismes méditerranéens et chiliens /." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37602992t.
Повний текст джерелаNoersomadi. "Characteristics of tropical tropopause and stratospheric gravity waves analyzed using high resolution temperature profiles from GNSS radio occultation." Kyoto University, 2019. http://hdl.handle.net/2433/242617.
Повний текст джерелаBureau, Jérôme. "Les raies moléculaires de l'atmosphère solaire dans l'infrarouge : spectroscopie, transfert radiatif et modélisation physico-chimique du CO et de ses isotopomères." Paris 6, 2009. http://www.theses.fr/2009PA066250.
Повний текст джерелаDixneuf, Sophie. "Spectroscopie de diffusion de la lumière dans les mélanges de gaz atomiques." Angers, 2006. https://tel.archives-ouvertes.fr/tel-01773264.
Повний текст джерелаThis thesis is a contribution to the study of the interaction-induced polarizabilities by rare gases, in both the coordinate and the frequency representation. For the first time, collision-induced Raman spectra by atomic gaseous mixtures were recorded, computed quantum mechanically, and interpreted. More specifically, anisotropic and isotropic Stokes spectral wings by room-temperature Ne-Ar were investigated up to 300 cm-1 , whereas the anisotropic wing of the Kr-Xe was explored up to 135 cm-1. For Ne-Ar, the best agreement between theory and experiment was found when modern ab initio interaction-induced polarizability input was used, i. E. Models obtained within coupled-custer or symmetry adapted perturbation theory associated to extended orbital basis sets. Nevertheless, none of those models was it able to satisfactorily reproduce the far anisotropic spectral wing of Ne-Ar. For heavier systems such as Ke-Xe, second order Møller-Plesset theory provided a very satisfactory spectral response. On the other hand, a new spectral inversion approach was developed as a device to access polarizability models consistent with experiment. The inversion was applied to pure argon and neon gases for which broad domains of detuning, probed by the group, ensured that the input spectral moments were properly converged. The optimized models were shown to correct the defects of the ab initio ones at short separations, essentially affecting the far wing of the spectra. Finally, a singurality-free anisotropy model for (Ne)2 and Ne-Ar was proposed as a simple but potential candidate to represent the physical anisotropy of atomic gases
Dufour, Gaëlle. "Spectroscopie moléculaire atmosphérique : mesures diode laser au laboratoire, inversion des spectres enregistrés sous ballon, modélisation photochimique et contribution à la validation satellitaire." Paris 6, 2004. http://www.theses.fr/2004PA066101.
Повний текст джерелаBenna, Mehdi. "Génération et inversion de données de propagation d'ondes radio à travers un noyau cométaire (simulation de l'expérience CONSERT)." Toulouse 3, 2002. http://www.theses.fr/2002TOU30116.
Повний текст джерелаFurtado, Neto Alexandre. "O potêncial de poço duplo e a molécula de amônia /." Guaratinguetá : [s.n.], 2012. http://hdl.handle.net/11449/91817.
Повний текст джерелаBanca: Denis Dalmazi
Banca: Manuel Bastos Malheiro de Oliveira
Resumo: O foco deste trabalho é o espectro de inversão da molécula de amônia, resultado do fenômeno do tunelamento quântico. Para isso, usamos um modelo simpli cado, uni- dimensional, suscetível a uma análise teórica rigorosa usando a mecânica quântica não- relativística. Dentre as diversas funções hamiltonianas já estudadas para este modelo, zemos uma rápida apreciação dos trabalhos de Cohen, Dennison-Uhlenbeck, Manning, Merzbacher e Rosen-Morse. Para um estudo mais profundo, usamos o potencial do poço duplo nito que, posteriormente, descobrimos já fora analisado por Peacock-López. Re- zemos a análise deste potencial usando um caminho diferente do realizado por aquele autor. Analisamos os casos limites para este potencial e notamos que realmente, nesses regimes, ele tende para um poço nito único ou dois poços nitos separados. Então, de- senvolvemos um software grá co centrado no pacote MINUIT, desenvolvido pelo CERN, para analisar e ajustar os parâmetros aos dados experimentais da amônia e, ao nal, comparamos os resultados obtidos com aqueles encontrados na literatura. No ajuste dos parâmetros à amônia, houve uma melhoria acentuada quando passamos de uma fórmula mais simples da massa reduzida para outra mais so sticada. No caso especí co do po- tencial de Peacock-López, a comparação revela que os nossos resultados, de uma maneira geral, são mais precisos. Nossa análise se soma àquelas que contêm uma discussão quan- titativa do potencial de poço duplo. Como parte integrante deste trabalho, uma versão unidimensional simétrica do potencial de Morse foi exatamente resolvida em termos de funções de Kummer e um par de equações transcendentes para as autoenergias. A tentativa de ajustar este resultado à molécula de amônia, porém, mostrou que os padrões de poço duplo deste potencial... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract:The focus of this work is the inversion spectrum of the ammonia molecule, a result of the phenomenon of quantum tunneling. For this, we use a simpli ed, one-dimensional model, amenable to a rigorous theoretical analysis using the non-relativistic quantum me- chanics. Among the various Hamiltonian functions previously studied for this model, we made a quick appraisal of the work of Cohen, Dennison-Uhlenbeck, Manning, Merzbacher and Rosen-Morse. For a deeper study, we used the nite double-well potential which, as we later discovered, had been considered by Peacock-López. We redid the analysis of this potential using a di¤erent path made by that author. We analyze the limiting cases for this potential and actually noticed that in these schemes, it tends to one nite well or two separate nite wells. So, we developed a graphical software centered on the MINUIT pack- age, developed by CERN, to analyze and adjust the parameters to the experimental data of ammonia and at the end, we compared the results with those found in the literature. In setting the parameters of ammonia, there was a marked improvement when we move from a simpler formula for the reduced mass to a more sophisticated one. In the speci c case of the potential of Peacock-López, the comparison shows that our results, in general, are more accurate and precise. Our analysis adds to those that contain a quantitative discussion of the double-well potential. As part of this work, a symmetric one-dimensional version of the Morse potential is exactly solved in terms of the Kummer functions and a pair of transcendental equations for the eigenenergies. Attempting to adjust this result to the ammonia molecule, however, showed that the double-well patterns of this potential well are irreconcilable with the energy spectrum of ammonia: Close pairs separated by long intervals
Mestre
Rakotomanga, Prisca. "Inversion de modèle et séparation de signaux de spectroscopie optique pour la caractérisation in vivo de tissus cutanés." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0329.
Повний текст джерелаThe detection of pre-cancerous biological tissues during clinical diagnosis is made possible by the development of optical spectroscopic methods, also known as optical biopsy. These methods make it possible to identify changes in the metabolism and structure of biological tissues. In this thesis, optical measurements are performed on skin tissues using an optical device that integrates two modalities: spatially resolved diffuse reflectance and autofluorescence. Spectra exploitation involves solving a non-linear inverse problem to estimate the optical properties using a light-tissue interaction model. From these optical properties, it is possible to characterize the condition of the tissue, healthy or abnormal. The first contribution of the thesis is to propose an inversion method that integrates a fast Monte Carlo model and a cost function managing two spectral modalities in order to improve the accuracy of the estimation of optical properties, regardless of the geometry of the probe. The second contribution is to study the kinetics of fluorophores present in tissues by a source separation approach, which does not require the use of a Monte Carlo model. In this approach, a collection of spectra acquired over time is analyzed together, with few a priori assumptions about the shape of the source signals. The sensitivity of this approach is validated by the use of optical clearing that increase tissue transparency by decreasing photon diffusion and absorption in tissues, thus providing access to more accurate in-depth information
Muñoz, Ramirez Oscar Mauricio. "Contributions on spectral control for the asymmetrical full bridge multilevel inverter." Doctoral thesis, Universitat Rovira i Virgili, 2010. http://hdl.handle.net/10803/8476.
Повний текст джерелаPrimero se han desarrollado dos modelos analíticos para predecir el espectro del voltage de salida, dependiendo de: el índice de modulación MA, la razón de distribución de voltaje K de las fuentes de alimentación , y las cuatro pendientes de las portadoras{r1, r2, r3, r4}. El primer modelo considera el Muestreo Natural y se basa en Series Dobles de Fourier (SDF) mientras que el segundo modelo, utiliza la Serie Sencilla de Fourier (SSF) introduciendo el concepto de Muestreo Pseudo-Natural, una aproximación digital de la modulación natural. Ambos modelos son programados en Matlab, verificados con Pspice y validados con un prototipo experimental que contiene un modulador digital implementado con DSP.
La concordancia entre las modulaciones natural y pseudo-natural, asi como entre sus respectivos modelos, es aprovechada por un algorítmo genético (AG) donde la THD es la función costo a reducir. Después de varios ensayos y de sintonizar el AG, se genera una matriz que contiene conjuntos de portadoras optimizadas dentro un rango específico de las variables {MA,K} y es probada con un segundo prototipo en lazo cerrado. Un lazo lento digital modifica las portadoras creadas por un dsPIC en modulaciones PWM; estas son demoduladas y sus amplitudes corregidas por un lazo de acción anticipada. Estas portadoras se comparan con una referencia sinusoidal que a su vez es modificada por variables de estado, generando finalmente la modulación multinivel en lazo cerrado. Los resultados finales demuestran la fiabilidad de la reducción de armónicos usando la programación de las pendientes de las portadoras.
Palabras claves: inversor multinivel, PWM, distorsión armónica, modelo espectral, pendiente de portadora, conjunto de portadoras, distribución de niveles, Serie Doble de Fourier, Serie Simple de Fourier, muestreo natural, muestreo regular, muestreo pseudo-natural , Algoritmos Genéticos.
Multilevel inverter (MI) topologies can work at higher voltage and higher power than conventional two-level converters. In addition, multilevel conversion reduces the output variables harmonic distortion and, sometimes, in spite of the devices-count increment, the conversion losses can also decrease by increasing the number of levels. The harmonic distortion reduction achieved by increasing the number of levels, can be used to further reducing the switching losses by decreasing the inverter carrier frequencies. To reduce even more the switching frequency without degrading output spectrum, we control the triangular carrier waveforms slopes.
First, to achieve this target, two analytical models have been created in order to predict the inverter output voltage spectrum, depending on diverse parameters: the amplitude modulation index MA, the voltage distribution K of the inverter input sources, and the four carrier slopes {r1, r2, r3, r4}. The first model considers Natural Sampling and is based on Double Fourier Series (DFS) whereas the second model based on Simple Fourier Series (SFS), introduces the concept of Pseudo-Natural Sampling, as a digital approximation of the natural modulation. Both models are programmed in Matlab, verified with Pspice simulations and validated with a first experimental prototype with a DSP digital modulator.
The good agreement between natural and pseudo-natural modulations, as well as their respective DFS and SFS models, is exploited by a Genetic Algorithm (GA) application where THD is the cost function to minimize. After testing and properly tuning the GA, a framework matrix containing the optimized carriers set for a specific range of variables {MA,K} is generated and then, tested with a second, closed-loop prototype. A slow digital loop modifies the carrier slopes created by dsPIC microcontroller as PWM modulations, whose amplitude, once demodulated, are affected by a feed-forward loop. These carriers, compared with a sinusoidal reference, state-feedback modified, generate finally the closed-loop multilevel modulation. The final results demonstrates the feasibility of harmonic reduction by means of carrier slopes programming.
Keywords: multilevel inverter, PWM, harmonic distortion, spectral modeling, carrier slope, carriers set, level distribution, Double Fourier Series, Simple Fourier Series, natural sampling, regular sampling, pseudo-natural sampling, Genetic Algorithms.
Matar, Christian. "Restitution des propriétés des nuages à partir des mesures multi-spectrales, multi-angulaires et polarisées du radiomètre aéroporté OSIRIS." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1R041/document.
Повний текст джерелаCloud feedbacks remain one of the major uncertainties of climate prediction models, particularly the interactions between aerosols, clouds and radiation (IPCC - Boucher et al., 2013). Clouds are indeed difficult to account for because they have significant spatial and temporal variability depending on a lot of meteorological variables and aerosol concentration. Airborne remote sensing measurements with tens of meters resolution are very suitable for improving and refining our knowledge of cloud properties and their high spatial variability. In this context, we exploit the multi-angular measurements of the new airborne radiometer OSIRIS (Observing System Including PolaRization in the Solar Infrared Spectrum), developed by the Laboratoire d'Optique Atmosphérique. It is based on the POLDER concept as a prototype of the future 3MI space instrument planned to be launched on the EUMETSAT-ESA MetOp-SG platform in 2022.In remote sensing applications, clouds are generally characterized by two optical properties: the Cloud Optical Thickness (COT) and the effective radius of the water/ice particles forming the cloud (Reff). Currently, most operational remote sensing algorithms used to extract these cloud properties from passive measurements are based on the construction of pre-computed lookup tables (LUT) under the assumption of a homogeneous plane-parallel cloud layer. The LUT method is very dependent on the simulation conditions chosen for their constructions and it is difficult to estimate the resulting uncertainties. In this thesis, we use the formalism of the optimal estimation method (Rodgers, 2000) to develop a flexible inversion method to retrieve COT and Reff using the visible and near-infrared multi-angular measurements of OSIRIS. We show that this method allows the exploitation of all available information for each pixel to overcome the angular effects of radiances and retrieve cloud properties more consistently using all measurements. We also applied the mathematical framework provided by the optimal estimation method to quantify the uncertainties on the retrieved parameters. Three types of errors were evaluated: (1) Errors related to measurement uncertainties, which reach 10% for high values of COT and Reff. (2) Model errors related to an incorrect estimation of the fixed parameters of the model (ocean surface wind, cloud altitude and effective variance of water droplet size distribution) that remain below 0.5% regardless of the values of retrieved COT and Reff. (3) Errors related to the simplified physical model that uses the classical homogeneous plan-parallel cloud assumption and the independent pixel approximation and hence does not take into account the heterogeneous vertical profiles and the 3D radiative transfer effects. These last two uncertainties turn out to be the most important
Bacour, Cédric. "Contribution à la détermination des paramètres biophysiques des couverts végétaux par inversion de modèles de réflectance : analyses de sensibilité comparatives et configurations optimales." Paris 7, 2001. http://www.theses.fr/2001PA077164.
Повний текст джерелаBazin, Cyrille. "L'interface photosphère solaire/chromosphère et couronne : apport des éclipses et des images EUV." Phd thesis, Aix-Marseille Université, 2013. http://tel.archives-ouvertes.fr/tel-00921889.
Повний текст джерелаBuchard, Virginie. "Caractérisation du contenu atmosphérique en ozone et en aérosols au moyen de mesures spectrales dans l'UV : validation de l'instrument spatial OMI / AURA." Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10025/document.
Повний текст джерелаSince the discovery of the stratospheric ozone reduction in the middle of the 1980's, a monitoring of the ozone layer and UV irradiance was organized, using ground-based and satellite instruments. Measurements of UV radiation allow both to monitor the intensity of this radiation reaching the surface and to retrieve atmospheric compounds as content of ozone and aerosol characteristics. The main part of this work concerns the analysis and the use of UV spectral measurements performed at Villeneuve d'Ascq (VdA) and at Briançon. We continued the restitution of the total column of ozone that provides a multi-year record of this quantity. We determined two aerosol parameters, the aerosol optical thickness (AOT) and the single scattering albedo; comparisons with photometric measurements from the AERONET/PHOTONS network appeared very good. The data obtained from September 2004 enabled us to be involved within the framework of an ESA project in the validation of the OMI/AURA instrument, which is dedicated to a global monitoring of ozone and UV. We have established that the OMI ozone products are very well retrieved, whereas spectral and erythemal dose UV have to be used with caution. At VdA, the comparisons between OMI-AOT and those derived fram graund-based measurements are not satisfying. Better results were obtained at six sites located in WesternAfrica region during the AMMA campaign, this region being influenced by high loads of absorbing aerasols
Luo, Qiu. "L'étude et l'application des méthodes inverses aux problèmes vibro-acoustiques." Compiègne, 1997. http://www.theses.fr/1997COMP1075.
Повний текст джерела