Дисертації з теми "Modélisation inversion"
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Bonnefond, Xavier. "Contributions à la tomographie thermoacoustique : modélisation et inversion." Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1155/.
ThermoAcoustic Tomography (TAT) is a medical imaging technique using the pressure wave generated by a body illuminated by an electromagnetic pulse. Since the acoustic signal is recorded around the body, the resulting inverse problem can be formulated as follows : from the knowledge of a solution of the wave equation on some hypersurface, reconstruct its initial condition. Despite several inversion formulas, so far no efficient procedure, taking partial data and damping into account, is known. As well as a state of the art, this work is dedicated to the introduction of a variational approach for the TAT problem. We studied the regularization by mollification, which consists in replacing the original object by a limited resolution version of it, and treating the data so that they fit this new objective. Moreover, we used a noise level estimation provided by the Golub-Kahan bidiagonalization process to allow an accurate regularization parameter selection. In the second part of this work, we investigate the usual TAT model and put forward some damped wave equation with a finite wave front speed. This improvement yields to the use of the Back and Forth Nudging (BFN) method, which was first implemented for data assimilation purposes, to invert the TAT problem. This technique provides a sequence of approximations of the solution by iterating forward and backward implementations of a wave equation including a newtonian recall to the data. This method, which is proved to be convergent in an ideal framework, leads to convincing results in both partial data and attenuated wave cases
Sladen, Anthony. "Modélisation non-linéaire des grands séismes de subduction." Paris 11, 2005. http://www.theses.fr/2005PA112098.
With the setting up of seismographic broad-band networks world wide in heighties, it has been possible to study the rupture process using information recorded in far-field. The inversion of seismograms to image the rupture, which is known for being highly non linear, is still commonly analysed using linearized methods. Based on this statement, we have developped an inversion method based on a stochastic algorithm called neighbourhood algorithm which has a certain number of avantages over other widely used algorithms. However, the need for a great number of variables for a kinematic inversion make it difficult to reach a good convergence. The alternative solution is to use a local exploration algorithm, the downhill simplex, in conjunction with the exploration phase. With a view to developping a simple and global method of inversion we use a simplified parametrization of the fault and the seismograms are generated from the ray theory. The methodology, aimed at pratical applications, is also a good way to evaluate the unicity of the problem and its resolution. We then set up a certain number of synthetic tests and used the well studied Antofagasta earthquake (30/07/1995) has a case study. Through this different examples we have concentrated on a certain number of essential points such as the resolution of P wave on the seismic moment, on the lateral and vertical distribution of the seismic rate and on the inversion of rupture velocity. We then invert for two major recent earthquakes : the Peruvian Aréquipa earthquake of the June 23rd, 2001 (Mw=8. 4) and of the Mexican Colima earthquake of January 22nd, 2003 (Mw=7. 6)
Dietrich, Michel. "Modélisation, traitements et inversion de profils de sismique marine." Brest, 1990. http://www.theses.fr/1990BRES2011.
Peyrat, Sophie. "Modélisation des tremblements de terre : rupture, rayonnement et inversion." Paris 11, 2001. http://www.theses.fr/2001PA112140.
Clarke, Richard William Barnes. "Modélisation et inversion de données cinématiques complexes en 3D." Pau, 1997. http://www.theses.fr/1997PAUU3010.
Hélie, Thomas. "Modélisation physique d'instruments de musique en systèmes dynamiques et inversion." Paris 11, 2002. http://www.theses.fr/2002PA112315.
This work deals with the modeling and the inversion process "sound/instrumental gesture" of musical instruments with like standard application : brasses and production of the voice. The physical modeling has large a interest for the sound synthesis since it generates not only the sound but also the behavior of the instrument (attacks, transients, false notes, etc). For these reasons, the difficulty of playing with virtual instruments is comparable to that of real instruments. The difficulty of controlling such models leads to the question of the inversion process : "how do I control my model to obtain this target sound that this musician obtained with his own instrument?" To cope with this problematic, we first indicate that the synthesis modeling and the associated inverse system may be thought together. Our thesis presents a work aiming to obtain mathematic objects as simple as possible. The problem of the excitor (lips, reeds, etc. . ) has been considered during our Master's Thesis. That of the resonator (description of the propagation in a pipe with a varying cross-section and its radiation) are thus the principal object of this work. In the first part, we establish a new model 1D of the acoustic propagation in axisymmetrical pipes with a slowly varying cross-section. This model makes it possible to take into account for example the motion of walls (case adapted with the vocal tract), or the existence of visco-thermic losses (which involes fractional derivatives). For this last case, it is possible of represent the whole guide by concatenating input-ouput systems associated with pieces of pipes locally adapted with the curvature of the pipe. As the involved transfer functions are too complicated to allow the derivation of a low cost time-simulation, we propose two methods which approach them with linear differential systems of finite order with delay. These methods are based on, respectively, troncated divergent series, and the theory of the diffusive representations of pseudo-differential operators. In the second part, a new model of the radiation of the bell which takes the wavefront curvature is developed and used to model the boundary condition at the output of the instrument. The results of this work may be used for the study of the brasses and, partially, for the vocal tract
Cognet, Jean-Marc. "Inversion sismique : identification du signal source et modélisation des réflexions multiples." Paris 9, 2001. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=2001PA090016.
Breton, Sylvain. "Dynamique des surfaces planétaires actives : quantification des paysages, modélisation et inversion." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1280.
Impact crater are often used in the study of planetary surfaces. On the one hand, statistics on crater number provide the age of the surface, on the other hand, their shapes reflect the surface processes they witnessed. This study combines the statistic and morphology approaches in order to investigate the timing and intensity of sedimentary and volcanic processes of planetary surfaces. The use of crater depth measurements add a dimension to frequency distributions with the introduction of size and depth frequency distribution (SDFD). SDFSs can be interpreted in term of crater obliteration rates thanks to crater chronology models. We also developed models of crater population taking into account obliteration. Mars surface is highly cratered with many craters displaying signs of modifications by volcanic process, sedimentation and erosion. We interpreted SDFDs using a classic crater chronology system, to produce global maps of obliteration at different epochs of Mars. During Noachian, obliteration rates reach several thousands m/Gy, but rapidly decrease during early Hesperian and are close to 0 during Amazonian. Obliteration on the province of Tharsis decreased slower, suggesting a persistence of volcanic activity until early Amazonian. Northern lowlands witness Amazonian obliteration rates one order of magnitude higher than the rest of the planet, which may indicate the continuous formation of Vastitas Borealis during middle Amazonian. In addition to our global approach, we computed recent obliteration rates from mapping of high resolution images on landing sites of rover missions. Mawrth Vallis and Oxia Planum present significant obliteration rates, especially on units containing hydrated minerals
Furst, Séverine. "Multi-objective optimization for joint inversion of geodetic data." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS017/document.
The Earth’s surface is affected by numerous local processes like volcanic events, landslides or earthquakes. Along with these natural processes, anthropogenic activities including extraction and storage of deep resources (e.g. minerals, hydrocarbons) shape the Earth at different space and time scales. These mechanisms produce ground deformation that can be detected by various geodetic instruments like GNSS, InSAR, tiltmeters, for example. The purpose of the thesis is to develop a numerical tool to provide the joint inversion of multiple geodetic data associated to plate deformation or volume strain change at depth. Four kinds of applications are targeted: interseismic plate deformation, volcano deformation, deep mining, and oil & gas extraction. Different inverse model complexities were considered: the I-level considers a single type of geodetic data with a time independent process. An application is made with inverting GPS data across southern California to determine the lateral variations of lithospheric rigidity (Furst et al., 2017). The II-level also accounts for a single type of geodetic data but with a time-dependent process. The joint determination of strain change history and the drift parameters of a tiltmeter network is studied through a synthetic example (Furst et al., submitted). The III-level considers different types of geodetic data and a timedependent process. A fictitious network made by GNSS, InSAR, tiltmeters and levelling surveys is defined to compute the time dependent volume change of a deep source of strain. We develop a methodology to implement these different levels of complexity in a single software. Because the inverse problem is possibly ill-posed, the functional to minimize may display several minima. Therefore, a global optimization algorithm is used (Mohammadi and Saïac, 2003). The forward part of the problem is treated by using a collection of numerical and analytical elastic models allowing to model the deformation processes at depth. Thanks to these numerical developments, new advances for inverse geodetic problems should be possible like the joint inversion of various types of geodetic data acquired for volcano monitoring. In this perspective, the possibility to determine by inverse problem the tiltmeter drift parameters should allow for a precise determination of deep strain sources. Also, the developed methodology can be used for an accurate monitoring of oil & gas reservoir deformation
Jurado, Fabrice. "Modélisation sismique et inversion non linéaire pour les milieux 3D élastiques tabulaires." Montpellier 2, 1992. http://www.theses.fr/1992MON20244.
Strubel, Grégory. "Reconstruction de profils moléculaires : modélisation et inversion d'une chaîne de mesure protéomique." Phd thesis, Grenoble INPG, 2008. http://www.theses.fr/2008INPG0127.
Systems based on chromatography and mass spectrometry are used to analyse biologic samples like urine or blood. This thesis proposes a method which measures the concentration of biomarkers in data. In the first part we elaborate a model which describes each module of the analytic chain. In order to manage experimental fluctuation, our method estimates some instrumental parameters in addition to concentrations. The second part deals with this non linear estimation problem in a Bayesian statistical framework. This approach gives us the possibility to include additional information by using probability laws to regularize the problem. The method is built on a posterior mean estimator. Its implementation uses a Gibbs algorithm including a Metropolis-Hastings sampler
Strubel, Grégory. "Reconstruction de profils moléculaires : modélisation et inversion d'une chaîne de mesure protéomique." Phd thesis, Grenoble INPG, 2008. http://tel.archives-ouvertes.fr/tel-00361919.
Molina, Carpio Luis. "Modélisation inverse des flux de CO2 en Amazonie." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV040/document.
A better knowledge of the seasonal and inter-annual variations of the Amazon carbon cycle is critical to understand the influence of this terrestrial ecosystem on climate change. Atmospheric inverse modeling is a powerful tool to estimate these variations by extracting the information on the spatio-temporal patterns of surface CO2 fluxes contained in observations of atmospheric CO2. However, the confidence in the Amazon flux estimates obtained from global inversion frameworks is low, given the scarcity of observations in this region.In this context, I started by analyzing in detail the Amazon net ecosystem exchange (NEE) inferred with two global inversions over the period 2002 — 2010. Both inversions assimilated data from the global observation network outside Amazonia, and one of them also assimilated data from four stations in Amazonia that had not been used in previous inversion efforts. I demonstrated that in a global inversion the observations from sites distant from Amazonia, as well as local observations, controlled the NEE inferred through the inversion. The inferred fluxes revealed large-scale structures likely not consistent with the actual NEE in Amazonia. This analysis confirmed the lack of observation sites in Amazonia to provide reliable flux estimates, and exposed the limitations of global frameworks, using low-resolution models to quantify regional fluxes. This limitations justified developing a regional approach.Then I evaluated the benefit of the regional atmospheric model BRAMS, relative to the global forecast system ECMWF, when both models provided the meteorological fields to drive the atmospheric transport model CHIMERE to simulate CO2 transport in tropical South America at high resolution (~35 km). I simulated the CO2 distribution with both transport models―CHIMERE-BRAMS and CHIMERE-ECMWF. I evaluated the model simulations with aircraft measurements in vertical profiles, analyzing the concentrations associated to the individual measurements, but also with horizontal gradients along wind direction between pairs of sites at different altitudes, or vertically integrated. Both transport models simulated the CO2 observations with similar performance, but I found a strong impact of the uncertainty in the transport models. Both individual measurements and horizontal gradients were most sensitive to NEE, but also to biomass burning CO2 emissions (EFIRE) in the dry season. I found that horizontal gradients were more suitable for inversions than individual measurements, since the former were less sensitive fluxes outside South America and further decreased the impact of the transport model uncertainty in altitude.Finally, I developed two analytical regional inversion systems for tropical South America, driven with CHIMERE-BRAMS and CHIMERE-ECMWF, and made inversions with four observation vectors: individual concentration measurements and horizontal gradients at five vertical levels, close to the surface, or horizontal gradients vertically integrated. I found a strong dependency of the inverted regional and sub-regional NEE and EFIRE emissions budgets on both the transport model and the observation vector. Inversions with gradients yielded a better separation of NEE and EFIRE signals. However, the large uncertainties in the inverted fluxes, did not yield high confidence in the estimates. Therefore, even though my study did not improve the knowledge of seasonal and year-to-year variations of the NEE in Amazonia, it demonstrated need of further efforts to improve transport modeling in the region and the inverse modeling strategy, at least through a careful definition of the observation vector that accounts for the characteristics of the available data, and the limitations of the current transport models
Ben, Hadj Ali Hafedh. "Three dimensional visco-acoustic frequency domain full waveform inversion." Nice, 2009. http://www.theses.fr/2009NICE4111.
In seismic exploration, it is crucial to extract from the recorded data the physical of the subsurface in order to correctly locate the potential reservoirs. In this context, seismic imaging is an important step in this quest. The imaging process has been for a long time based on a two-scale strategy : the first step consists in building a smooth velocity model, which correctly explains the kinematics, and the second step in taking into account the dynamics through a migration process to detect reflectivity contrasts. In the eighties, a quantitative imaging method, called waveform inversion, has been proposed to bring together the two stages in an integrated approach. The objective of waveform inversion is to build the whole spectrum of wavenumbers by exploiting all the recorded arrivals acquired by wide aperture acquisitions. The method is formulated as a least squares optimization problem which aims to minimize the differences between the recorded and the modelled data. During the last few years, the waveform inversion method has been a main research topic in the academic and industrial communities. Many issues related to the starting anisotropy and elasticity, and the transition from 2-D to 3-D have been investigated. In this context, the objective of this thesis is to investigate and to develop a waveform inversion approach in the frequency domain and within the visco-acoustic approximation for the reconstruction of a 3-D subsurface model where the model is parametrized by the P-waves velocity, density and attenuation
Moudden, Yassir. "Estimation de paramètres physiques de combustion par modélisation du signal d'ionisation et inversion paramétrique." Paris 11, 2003. http://www.theses.fr/2003PA112004.
The work described in this thesis investigates the possibility of constructing an indirect measurement algorithm of relevant combustion parameters based on ionization signal processing. Indeed, automobile manufacturers are in need of low cost combustion diagnoses to enhance engine control. Because of the extreme complexity of the physical phenomena in which the ionization signal originates, the traditional model-based approach appeared unrealistic and did not bring about conclusive results. We hence turned to performing a blind statistical analysis of experimental data acquired on a test engine. The analysis of high dimensional data being notoriously awkward, it is necessary to first reduce the apparent dimension of the signal data, keeping in mind the necessity of preserving the information useful in terms of our estimation problem. The usual techniques such as Principal Component Analysis, Projection Pursuit, etc. Are used to form and detect relevant variables. Further, a procedure for high dimensional data analysis derived as an extension of Exploratory Projection Pursuit, is suggested and shown to be a profitable tool. With this method, we seek interesting projections of high dimensional data by optimizing probabilistic measures of dependence such as Mutual Information, Hellinger divergence, etc. Finally, results are presented that demonstrate the quality and the stability of the low complexity in-cylinder peak pressure position estimators we derived, for a wide range of engine states
Benachir, Mohcine. "Simulation numérique et modélisation des transistors MOS sur silicium sur isolant à inversion volumique." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0090.
Birrien, Florent. "Assimilation de données et inversion bathymétrique pour la modélisation de l'évolution des plages sableuses." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00870775.
Molina, Carpio Luis. "Modélisation inverse des flux de CO2 en Amazonie." Electronic Thesis or Diss., Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV040.
A better knowledge of the seasonal and inter-annual variations of the Amazon carbon cycle is critical to understand the influence of this terrestrial ecosystem on climate change. Atmospheric inverse modeling is a powerful tool to estimate these variations by extracting the information on the spatio-temporal patterns of surface CO2 fluxes contained in observations of atmospheric CO2. However, the confidence in the Amazon flux estimates obtained from global inversion frameworks is low, given the scarcity of observations in this region.In this context, I started by analyzing in detail the Amazon net ecosystem exchange (NEE) inferred with two global inversions over the period 2002 — 2010. Both inversions assimilated data from the global observation network outside Amazonia, and one of them also assimilated data from four stations in Amazonia that had not been used in previous inversion efforts. I demonstrated that in a global inversion the observations from sites distant from Amazonia, as well as local observations, controlled the NEE inferred through the inversion. The inferred fluxes revealed large-scale structures likely not consistent with the actual NEE in Amazonia. This analysis confirmed the lack of observation sites in Amazonia to provide reliable flux estimates, and exposed the limitations of global frameworks, using low-resolution models to quantify regional fluxes. This limitations justified developing a regional approach.Then I evaluated the benefit of the regional atmospheric model BRAMS, relative to the global forecast system ECMWF, when both models provided the meteorological fields to drive the atmospheric transport model CHIMERE to simulate CO2 transport in tropical South America at high resolution (~35 km). I simulated the CO2 distribution with both transport models―CHIMERE-BRAMS and CHIMERE-ECMWF. I evaluated the model simulations with aircraft measurements in vertical profiles, analyzing the concentrations associated to the individual measurements, but also with horizontal gradients along wind direction between pairs of sites at different altitudes, or vertically integrated. Both transport models simulated the CO2 observations with similar performance, but I found a strong impact of the uncertainty in the transport models. Both individual measurements and horizontal gradients were most sensitive to NEE, but also to biomass burning CO2 emissions (EFIRE) in the dry season. I found that horizontal gradients were more suitable for inversions than individual measurements, since the former were less sensitive fluxes outside South America and further decreased the impact of the transport model uncertainty in altitude.Finally, I developed two analytical regional inversion systems for tropical South America, driven with CHIMERE-BRAMS and CHIMERE-ECMWF, and made inversions with four observation vectors: individual concentration measurements and horizontal gradients at five vertical levels, close to the surface, or horizontal gradients vertically integrated. I found a strong dependency of the inverted regional and sub-regional NEE and EFIRE emissions budgets on both the transport model and the observation vector. Inversions with gradients yielded a better separation of NEE and EFIRE signals. However, the large uncertainties in the inverted fluxes, did not yield high confidence in the estimates. Therefore, even though my study did not improve the knowledge of seasonal and year-to-year variations of the NEE in Amazonia, it demonstrated need of further efforts to improve transport modeling in the region and the inverse modeling strategy, at least through a careful definition of the observation vector that accounts for the characteristics of the available data, and the limitations of the current transport models
Marescot, Laurent. "Modélisation directe et inverse en prospection électrique sur les structures 3D complexes par la méthode des éléments finis." Nantes, 2004. http://www.theses.fr/2004NANT2087.
This work presents the adaptation and the use of the CESAR-LCPC finite element code for the forward and inverse modelling of 3D resistivity data. A forward modelling tool was created to simulate tomographies with CESAR and an inversion code was also presented for the processing of resistivity tomographies on complex 3D structures using any electrode arrangement. This algorithm is well suited for the processing of large data sets with a lot of unknown model parameters. The inversion code uses an original strategy to avoid the explicit calculation of a sensitivity matrix. The adjoint-state of the potential field is used to minimize an objective function for the electrical inverse problem. Finally, a ROI (Region Of Investigation) index method is used to assess whether features in the model are caused by the data or are artefacts of the inversion process
Lahet, Florence. "Caractérisation optique d'eaux côtières mediterraneennes : mesure, modélisation et inversion des réflectances. Application aux observations satellitales." Toulon, 1999. http://www.theses.fr/1999TOUL0012.
The determination of water quality parameters in coastal waters is tackled by experimental and algorithmic approaches. The experimental aspect includes measurements of attenuation coefficient and reflectance. The algorithmic method is based on a semi-analytic approach. A three-component reflectance model, that takes into account the contributions of dissolved organic matter, phytoplankton and mineral particles is inverted in order to estimate the chlorophyll a concentration, chl, the sediment refractive index, mr, and the absorption coefficient of disoived organic matter at 440 nm, ^(440), from experimental reflectance spectra and suspended sediments concentrations, C. The inversion procedure, based on the minimization of the quadratic difference between modelled and experimental reflectance values, is applied to experimental data collected in the Ebro River mouth area. It appears that chl values are not accurately retrieved using the proposed method and that mr and a, (440) values are realistic as compared to those previously published and little sensitive to chl variations. A colour classification of the study area waters is introduced in order to improve the precision of chl estimates. Each water class is associated with typical values of C, chl, m, and av(440) and correlations are established between the first derivative of reflectance and those four parameters. Associating an empiric method and a semi-analytic method allows the concurrent estimate of suspended sediment and chlorophyll a concentrations with variation coefficients lower than 50 %, The proposed method consists in estimating chl from empirical algorithms then C and av(440) are determined by inversion of the reflectance model parameterized from the mean value of mr typical of the water class considered and from the empirical value of chl. Finally, we examine the extension of our method of water quality parameters restitution by considering the reflectances sampled at the wavelengths of MERIS channels
Arnst, Maarten. "Inversion de modèles probabilistes de structures à partir de fonctionsde transfert expérimentales." Phd thesis, Ecole Centrale Paris, 2007. http://tel.archives-ouvertes.fr/tel-00238573.
Sandu, Leontina. "Inversion de modèles paramétriques : application aux mesures indirectes de températures." Paris 11, 1996. http://www.theses.fr/1996PA112343.
The general context of this work is the non-linear reconstruction of a mesurand or so-called the non-linear inverse problem with a very small data set. We are concerned with an inverse problem of heat conduction that deals with the determination of the internaI temperature from measured temperatures outside a heat conducting body. Ln order to solve this measurement problem, we propose different modelling techniques: analytical, numerical and the tehnique using external parametric models. Good existing results obtained from parametric estimation of temperature profiles lead us to study more deeply the external parametric models. Previous work has also demonstrated the interest of parametric functions as forward model for other applications. Those functions are simple to implement and result in good pelformance of the inversion process. We study the problem of construction of some candidates for parametric models. The discrimination between candidates is studied. Some theoretical notions for construction of parametric functions are advanced. We demonstrate that the choice of the parametric function depends on the significant quantity to estimate. This quantity could be the parameter vector, the model function in some points "inaccessible" to observation or an other parametric function. The proposed criteria choose the "best" function with respect to the inversion goal using the information gained in the experiment. The best model will be specific to the measurement goal and must be "sufficiently" close to real observations. Instruments for temperature measurement or other physical quantities measurement could include this type of model
Edouard, David. "Modélisation et supervision d'un réacteur à inversion de flux pour la destruction de composés organiques volatils." Lyon 1, 2003. http://www.theses.fr/2003LYO10198.
Nalpas, Thierry. "Inversion des grabens du sud de la mer du Nord. Données de sub-surface et modélisation analogique." Phd thesis, Université Rennes 1, 1994. http://tel.archives-ouvertes.fr/tel-00656044.
Dupuy, Bastien. "Propagation des ondes sismiques dans les milieux multiphasiques hétérogènes : modélisation numérique, sensibilité et inversion des paramètres poroélastiques." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00657366.
Lenot, Xavier. "Modélisation et inversion d'images hyperspectrales : quantification et prise en compte du relief et de la réflectance bidirectionnelle." Toulouse, ENSAE, 2005. http://www.theses.fr/2005ESAE0009.
Gaubert, Quentin. "Caractérisation et modélisation des phénomènes gouvernant le séchage par atomisation de suspensions colloïdales." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0300/document.
This PhD work takes place in the framework of researches on the optimization of the spray drying of colloidal suspensions used for catalyst support production. To better understand fundamental phenomena governing this process, the problem is reduced to the experimental study and modelling of the drying of a single droplet levitated in an acoustic field with an external gas flow. The experiment allows also controlling parameters such as composition of the suspension, temperature or humidity inside evaporation chamber. The drying is monitored using in situ optical diagnostics (particle image velocimetry, shadowgraphy and rainbow diffractometry) as well as post-mortem analyzes. The use of rainbow diffractometry has required the development of advanced light scattering models accounting for the droplet non-sphericity and heterogeneity. The drying model is a model with radial symmetry. It predicts various quantities such as the droplet evaporation rate, internal concentration profile or the deformation of the final grain. Experimental comparisons show that this model can accurately predicts the drying rate of colloidal droplet for Reynolds numbers ranging from 100 to 230, temperatures between 25°C and 55°C and relative humidity between 2.5% and 70%. It is also shown that the crust compactness factor, about 12% when identified from the change in the rate of evaporation, is much lower than that reported classically for the jamming of dense suspensions
Lévesque, Martin. "Modélisation du comportement mécanique de matériaux composites viscoélastiques non linéaires par une approche d'homogénéisation." Paris, ENSAM, 2004. https://pastel.archives-ouvertes.fr/pastel-00001237.
The main objective of this thesis is to develop a model, based on homogenisation, for predicting the mechanical response of nonlinear viscoelastic composites. The model is applied to a glass beads reinforced polypropylene in which the beads are randomly distributed. The initial part of the thesis is concerned with the development of a three dimensional nonlinear viscoelastic constitutive law that can be applied to this polypropylene composite. The second stage of the thesis deals with the development and identification of the homogenisation model while this theoretical model is presented in Chapter Three. This approach allows material models, for which the response does not depend on the load history, to be applied to nonlinear viscoelastic materials. The approach involves transforming the initial nonlinear viscoelastic problem into one which is linear viscoelastic with a history of stress-free deformations. This problem is solved with the linear viscoelastic correspondence principle and Laplace-Carson transforms. Chapter Four deals with the numerical implementation of such a model. The implementation is achieved in such a way that the comparison materials, which represent the new linear viscoelastic problem, satisfy all thermodynamic requirements. Moreover, a new algorithm has been developed to numerically invert the Laplace-Carson transforms with good accuracy. The final part of the thesis validates the theoretical model through means of finite element models of typical microstructures and the numerical implementation of the nonlinear viscoelastic constitutive law. Comparisons are also presented between the predictions of the homogenisation model, the fi(…)
Wehr, Hannah. "Modélisation 3D des Pyrénées à partir des données géologiques, gravimétriques et sismiques." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30317/document.
A three-dimensional geological model of the Pyrenees and their foreland basins is constructed with the GeoModeller software. This model accounts for all the geological and geophysical information available and covers the whole Pyrenees, from the Atlantic Ocean to the Mediterranean Sea, and from the Iberian Range to the Massif Central, down to 70 km depth. It is able to explain main features of Bouguer gravity anomalies and of seismic travel times. 3D inversion is performed to refine this model. Joint geological and geophysical modeling and inversion reveal differences in the crustal structure between the western and central Pyrenees and the eastern Pyrenees. They show furthermore the presence of exhumed mantle material enclosed in the crust beneath the Labourd Massif and Saint-Gaudens, as well as the necessity of a low density anomalie in the eastern Pyrenees
Cisonni, Julien. "Modélisation et inversion d'un système complexe de production de signaux acoustiques : application à la voix et aux pathologies." Phd thesis, Grenoble INPG, 2008. http://www.theses.fr/2008INPG0103.
Physical modeling of phonation intends to explain and reproduce the phenomena occurring during the vocal folds oscillations, which generate the acoustical signal of the voiced sounds of speech. This thesis proposes at first an experimental study and the modeling of the influence of different mechanical, geometrical and acoustical conditions on the oscillations properties of vocal folds deformable replicas. A particular attention is then paid to the glottal flow modeling. The inversion of one-dimensional models is used to estimate quantities generally considered as input/control parameters. A 2D laminar flow model based on the finite element method is implemented in order to describe more precisely the glottal flow. Flow models predictions are compared to in-vitro measurements performed on vocal folds rigid replicas for several conditions
Cisonni, Julien. "Modélisation et inversion d'un système complexe de production de signaux acoustiques : application à la voix et aux pathologies." Phd thesis, Grenoble INPG, 2008. http://tel.archives-ouvertes.fr/tel-00363714.
Penz, Sébastien. "Modélisation et inversion de données électriques en courant continu : vers une prise en compte efficace de la topographie." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2012. http://pastel.archives-ouvertes.fr/pastel-00796438.
Penz, Sébastien. "Modélisation et inversion de données électriques en courant continu : vers une prise en compte efficace de la topographie." Electronic Thesis or Diss., Paris, ENMP, 2012. http://www.theses.fr/2012ENMP0016.
DC resistivity imaging plays an important role for a wide range of applications related to the characterization of the shallow subsurface. Major developments have been made over the last two decades to improve acquisition systems as well as resistivity inversion. Nevertheless, large-scale data sets still represent a challenging task, in particular with arbitrary topography. In order to better take into account topography, we have developed a new 2.5D/3D tomographic inversion code. Two new formulations for the singularity removal have been proposed. The direct problem is solved in the framework of the Generalized Finite Differences Method, that allows the use of unstructured meshes yielding a fine represention of topography. The inversion code uses the adjoint state method to compute the gradient of the misfit function in a numerically efficient way, giving goodresults on synthetic data. First results on real data have shown the main subsurface structures, as well as several low resistivity zones possibly corresponding to fractured areas
Lejri, Mostfa. "Subsurface stress inversion modeling using linear elasticity : sensitivity analysis and applications." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS212/document.
Today, one of the main challenges in the oil industry, especially during the exploration phase, is the exploitation of new resources in structurally complex areas such as naturally fractured reservoirs, salt diapirs, mountain ranges, and unconventional reservoirs.We know that the geometry and sliding along active faults modifies the local stress distribution. Knowing the present day perturbed stress field is important for the study of earthquakes, for the planning of the borehole drilling and stability as well as for the prediction of fractures induced by hydro-fracturing and reactivation of natural fractures. In the other side, perturbed paleostress are responsible for the development of (pre-existing) natural fractures. The detection and modeling of the latter, are essential both in the oil industry (migration and trapping of fluids) for a cost efficient recovery of natural reserves.Understanding and quantifying the spatial and temporal development of the stress distribution has a significant economic and environmental impact. The analysis of paleo-constraints was intuitively introduced first by Anderson (1905 & 1942), then in the middle of the last century, Wallace (1951) and Bott (1959) proposed the simple hypothesis that (i) The stress field is homogeneous in space and constant in time, and that (ii) the slip direction is parallel to the traction projected on the fault plane which gives the direction of the shear stress. Many stress inversion methods are based on this hypothesis while recent studies raise doubts as to their compatibility with rock mechanics.In order to investigate the validity of the Wallace and Bott hypothesis, a comparison with vectors of slip generated with numerical models (BEM) is performed. By testing the influence of multiple parameters (geometry, boundary conditions, friction, Poisson’s coefficient , half-space, fault fluid pressure), it is shown that the complex geometry faults subject to specific boundary conditions can yield slip vectors with significant discrepancies with the maximum shear stress resolved on the fault plane. Conversely, the presence of a high sliding friction, allows under certain conditions, to validate the hypothesis of Wallace and Bott.We then focus on the task to compare the results of stress inversions based on the assumption of Wallace and Bott (called classical stress inversion methods) to a geomechanical method. For this, a complex fault geometry is used in a sensitivity analysis (boundary conditions, friction, sampling) to evaluate the uncertainty of the results of the two inversion methods. This analysis is then compared to a case study, Chimney Rock (Utah, USA), showing the advantages and disadvantages of the classical stress inversion methods.One of the main challenges of the oil industry is the exploitation of resource in structurally complex oil fields such as naturally fractured reservoirs. Knowing the heterogeneous paleostress allows to optimize the modeling of these natural fractures. Since slip on faults is hardly observed in petroleum reservoirs, fracture orientation data (joints, faults, stylolites) are naturally taken into account during the inversion of stresses. It is shown, using various field and industry examples, that in such cases the use of mechanical stress inversions is much more appropriate.However, it is sometimes difficult to determine the fracture kinematics observed along wellbores, and very often the studied regions underwent multiple tectonic phases. The final section aims to address the problem of data with unknown kinematic (joints, faults, stylolites ...) and expends the mechanical stress inversion to the separation of tectonic phases
Wang, Chao. "Inversion of lunar FeO and numerical simulation of the detached dust layers on Mars." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066734/document.
Moon and Mars have been the important targets for deep space missions. The studies in this thesis include two parts. The first part is concerning Chang’e-1 Interference Imaging Spectrometer (IIM) data preprocessing and global lunar FeO inversion. In order to better preprocess the IIM data, a new method using spectral angle and Euclidean distance for removing bad pixels has been proposed. A new in-flight calibration has been conducted. And cross calibration of IIM data by using the telescopic data is improved. The processed IIM data have also been used to inverse lunar FeO abundance. The IIM-derived FeO is comparable to Clementine FeO results, and can be an alternative dataset for Moon studies. The second part is concerning parameterizing rocket dust storms and daytime slope winds in LMD (Laboratoire de Météorologie Dynamique) Mars GCM (Global Climate Model) to reproduce the detached dust layers (DDLs) observed by Mars Climate Sounder (MCS) on Mars. The simulations by the GCM including rocket dust storm parameterization show that, during the Martian dusty seasons, the rocket dust storms are the key factors to explain the observed DDLs. The formation and evolution of GCM simulated DDLs are in agreement with those of MCS observation. Meanwhile, the simulation also suggests that the large variation of the DDLs’ altitudes in dusty season are contributed by the deep convection induced by rocket dust storms. The simulations by the GCM including daytime slope winds parameterization show that with the help of daytime slope winds, the GCM can reproduce the detached dust layers in Martian clear seasons, which cannot be simulated by the rocket dust storm process
Pianelo, Laurent. "Modélisation géologique contrainte par les données sismiques et dynamiques." Aix-Marseille 1, 2001. http://www.theses.fr/2001AIX11042.
De, Barros Louis. "Sensibilité et inversion des formes d'ondes sismiques en milieu poreux stratifié." Grenoble 1, 2007. http://www.theses.fr/2007GRE10275.
Characterisation of porous media parameters, and particularly the porosity, penneability and fluid properties are very useful in many applications. The aim ofthis study is to evaluate the possibility to detennine the se properties from the full seismic wave fields. First, 1 present the poro-elastic parameters and the specific properties of the seismic waves in porous media. Seismic wave propagation are then computed in fluid saturated stratified porous media with a reflectivity method. This computation is first used to study the possibilities to detennine the carbon dioxide concentration and localisation in the case of a deep geological storage. The sensitivity of the seismic response to the poro-elastic parameters are then generalized by the analytical computation of the Fréchet derivatives which are expressed in tenns of the Green's functions of the unperturbed medium. The sensitivity operators are then introduced in a inversion algorithm based on iterative modelling ofthe full wavefonn. The classical algorithm of generalized least-square inverse problem is solved by the quasi-Newton technique (Tarantola, 1984). The inversion of synthetic data show that we can invert for the porosity and the fluid and solid parameters can be correctly rebuilt if the other parameters are well known. However, the strong seismic coupling of the porous parameters leads to difficulties to invert simultaneously for several parameters. Finally, 1 apply this algorithm on real data recorded on the coastal site of Maguelonne (Hérault)
Li, Liang. "Modélisation gros grain de macromolécules végétales : champ de force paramétré par dynamique moléculaire et application à des assemblages cellulose-xylane." Thesis, Paris, AgroParisTech, 2013. http://www.theses.fr/2013AGPT0087/document.
Nowadays, the understanding of plant cell walls' structure-properties relationship leans more and more on the use of molecular modeling approaches and of molecular dynamics in particular. To date, numerical weight of such an approach is usually out of the reach of available computing power if the atomic scale is used. As a consequence, building approximate methods is of crucial importance to perform numerical simulation of realistic supramolecular systems. Within the framework of this PhD, a “coarse grain” molecular dynamics model was built at plant cell wall macromolecule monomer's scale, it's parameters being fixed with the help of atom-scale molecular dynamics simulations. Then, several numerical studies were carried out: a single xylan chain was adsorbed on a crystalline cellulose surface, a single xylan chain was pulled from a crystalline cellulose surface with the help of the tip of an AFM cantilever, an amorphous xylan phase was adsorbed on a cellulose surface and an amorphous xylan phase was adsorbed on a cellulose crystal, which three surfaces were exposed. Local structuring effects were observed
GASCON, Ferran. "Modélisation physique d'images de télédétection optique." Phd thesis, Université Paul Sabatier - Toulouse III, 2001. http://tel.archives-ouvertes.fr/tel-00009863.
Peyrefitte, Aurélie. "Etude multi-échelle de la plaque africaine par analyse des données gravimétriques et gradiométriques de la mission GOCE." Paris 7, 2013. http://www.theses.fr/2013PA077153.
The GOCE (Gravity field and steady-state Ocean Circulation Explorer) satellite mission, of the European Space Agency (ESA) is mapping the global Earth' s gravity field with unprecedented detail. Furthermore, for the l' time, GOCE provides the measurements of the gravity tensor components at the global scale. Due to the attenuation of the gradiometric signal, this new type of data should be more sensitive to shallow structures than usual gravity anomaly data. And because of their directionality, gravity gradients shall provide better constraints on the geometry of the sources. First comparison between a gravity field model derived from eighteen months of GOCE data and previous models displays significant differences, particularly in Africa and the Himalayas. The african continent is one of the less understood areas of the Earth at the regional scale as in geological and geodynamical term. This is due to the paucity of geophysical datasets on the continent as well as to the complexity of the African geology. We present a multi-scale study of the african plate based on the complementarity of the two kinds of GOCE data and the join used of two 3D density model mainly based on sieismology: CRUST 2. 0 and The Global Digital Map of Sediment thickness. In the first part, we isolate the gravity response of the african mantle by comparing the GOCE gravity field model and the gravity effect of a 3D density model of the african crust at continental scale. In the second part, on a doser scale, we investigate the contribution of the gravity tensor components for the knowledge and the characterization of regional geological domains For that, we computec the forward gravity and gradiometric responses caused by a 3D density crustal model of a part of africa centered on the Congo and shown by inversion of the gravity field and/or gravity tensor components that the depth of the Congo basin is over-estimated in our initial 3D model. All the inversion calculations performed demonstrate the complementarity of gravity and gradiometric data and attest to the information gain brought by their joint use
Passalacqua, Olivier. "Localiser une archive glaciaire de 1.5 millions d'années par une approche multi-modèles." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAU024/document.
Antarctic ice is an exceptional archive of ancient atmospheric air. The oldest available ice archive (800 ka) is not old enough to study a main climatic transition that occurred between 1.2 Ma and 0.9 Ma (mid-Pleistocene transition). Locating a future old-ice drill site is now one of the main goal of the ice-core community. In the region of Dome C, several old-ice targets have required characteristics, from a thermal and mechanical point of view, to hosts very old ice. The goal of this work is to precisely locate suitable coring sites, using several glaciological models. First a 1D heat model to compute the local geothermal flux, that make us confident in the fact that bedrock heights have been free of basal melting for at least the last 800 ka. It is very likely that such sites are able to host a 1.5 Ma ice archive. Second, a 3D ice flow model, to describe the ice trajectories from the ice surface to the bed. Drilling less than 10 km from the surface ridge mimimizes the risks of stratigraphic disturbance, and drilling on the flanks of the bed relief - and not on its top - is mandatory to ensure a sufficient age resolution. Third, a 1D dating model constrained by isochrones let us describe the distribution of basal ages and age resolutions compatible with observed isochrones, and assess the risk of success or failure of the drilling. With currently available data and modelling tools, two drilling sites are proposed that are located 37 km from Dome C, at which 1.5 Ma-old ice is very likely to be archived in required conditions and with sufficient resolution
Kanj, Mahmoud. "Inversion de données électromagnétiques par algorithme génétique pour la télédétection en zone forestière." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112350/document.
The objective of radar imaging is to characterize the observed target. In the case of forest remote sensing, the objective is to extract the component of the vegetation physical parameters.This manuscript addresses the problem of the inversion of electromagnetic data for low frequency wave, VHF band to the P band. In these frequency bands, the canopy (leaves and small branches) does not almost interact with the radar wave and the forest can thus, in first approximation, be represented by vertical cylinders (trunks) and tilted (primary branches).In this context, the numerical electromagnetic methods of inversion lean on models which calculate, many times, the scattered fields radiated by such broadcasters. It is then necessary to choose a physical model which compromise speed/accuracy tilts in favor of the speed, thus a "approached" model. The exactness of the chosen model is then studied and then validated by comparison to a model which the compromise speed/accuracy is inverted, thus a "exact" model. Among the many numerical methods of inversion, that of the genetic algorithm (AG) was chosen. This algorithm, well known, is analyzed here then improved to meet the requirements of the composed electromagnetic problem. It is then validated on simulated and measured data. This validation is also an opportunity to study the impact of the set of data used on the speed and the precision of the inversion, according to the configurations of antenna (frequencies, positions, polarizations)
Tocheport, Audrey. "Modélisation cinématique de la rupture sismique : Approche détaillée du séisme de Kokoxili (14 Novembre 2001), approche globale appliquée aux séismes intermédiaires et profonds." Université Louis Pasteur (Strasbourg) (1971-2008), 2006. https://publication-theses.unistra.fr/public/theses_doctorat/2006/TOCHEPORT_Audrey_2006.pdf.
This thesis is about the kinematic study of seismic source of major events from teleseismic bodywaves. Two approaches have been used to recover the main source parameters. A first approach consists in imaging in detail the rupture caused by the Mw=7. 8 14 november 2001 Kokoxili earthquake by modeling bodywaves. We are in particular interested in understanding the initial phase of the rupture in the west around the epicentral area where fault geometry is more complex than in the east. In a second approach, we develop a fast new method for estimating source parameters of deep earthquakes (source time function, seismic moment, moment tensor, radiated energy). It is based on a simple analysis of P, pP and S waveforms recorded at teleseismic distances and avoids their modeling. This method has been applied to events having a Mw > 6,5 and deeper than 100 km during period 1990-2006. The results of this first step are then used to recover information about the spatial finiteness of the source
Beldjoudi, Hamoud. "Modélisation de la source des séismes par inversion des données sismologiques et géodésiques : application aux séismes du Nord de l’Algérie." Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4053/document.
Studies of the earthquake source are based on observations of seismic and static ground motions, which depend on the quality and the density of measurements. In this thesis, we present studies of the determination of the focal mechanism of the Tadjena (Mw 5.0, 2006), Béni-Ilmane (Mw 5.5, 2010), Hammam Melouane (Mw 5.0, 2013), Bordj-Ménaïel (Mw 4.1, 2014), Alger (Mw 5.7, 2014) and M’ziraa (Mw 5.1, 2016) earthquakes, by modeling waveforms in the near and regional field with broadband and strong motion stations of the Algerian Digital Seismic Netwok (ADSN). In addition, we determined the coseismic slip distribution of the Boumerdes-Zemmouri earthquake (Mw 6.8, 2003) by inverting a most comprehensive set of data (teleseismic, strong motion, GPS, InSAR, coastal uplift). We calculated the Coulomb Failure Function between the Boumerdes-Zemmouri earthquake (source fault) and the Hammam Melouane, Bordj Ménaïel and Algiers (Mw 5.7, 2014) events (receiver faults). We computed the stress tensor in different regions of Algeria obtained from the inversion of the available focal mechanisms
Valentian, Alexandre. "Etude de la technologie SOI partiellement désertée à très basse tension pour minimiser l'énergie dissipée et application à des opérateurs de calcul." Phd thesis, Télécom ParisTech, 2005. http://pastel.archives-ouvertes.fr/pastel-00001293.
Bureau, 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.
Louati, Sihem. "Acquisition, traitement, analyse, modélisation et inversion des enregistrements de bruit de fond sismique : application : les berges du lac sud de Tunis." Paris 6, 2013. http://www.theses.fr/2013PA066475.
The analysis and characterization of the sub-soil can be performed using several geophysical methods and surveys. These methods include traditional seismic methods (active or passive) that require the use of natural or artificial seismic sources and whose application is limited by the characteristics of the sources. After the finding of Nakamura theory (1989), a recent passive seismic technique consist to record the ambient seismic noise is established. To analyze the seismic risk of south lake banks of Tunis City, we have used this method. Campaigns measures in the field of study leads to the determination of seismic micro-zoning maps and identification of origin of these signals. Using several numerical simulations, the development of the relationship between a soil column and the results of these ambient seismic noise recordings is achieved. The estimation of the propagation of a seismic source through a column of tabular soil is performed. Then, a distribution of noise sources in both surface and subsurface is made and an estimation of the seismic signal generated by this two-dimensional distribution is performed. Geophysical and geotechnical site characterization study allows the comparison between these results and the results from an inversion of the curves H/V. This comparison reassures outcomes deriving records seismic noise
Audouin, Olivier. "Intégration - inversion de données géologique et mesures hydrodynamiques in-situ pour le conditionnement d'un modèle 3D d'aquifère calcaire : site expérimental hydrogéologique (SEH) de Poitiers, France." Poitiers, 2007. http://www.theses.fr/2007POIT2294.
This work synthesizes knowledge about the aquifer investigated by the Hydrogeological Experimental Site of Poitiers. Flowpath structure has been identified from lithostratigraphic core analysis and borehole logging data. The flow is governed by karstic structures and fractures. Karstic levels are constrained within 3 sub-horizontal geological levels. The interconnectivity between these levels seems controlled by the sub-vertical fractures. The hydrodynamic characterization of flowpaths is based on the interpretation of slug test. A new model has been developed, which takes into account inertial effects and fractional flow dimension. Sensibility analysis shows that the two key parameters are the flow dimension and the hydraulic conductivity. The results show that diffusivity values of hydraulic connection vary over several orders of magnitude and allow hydraulic response at far observation wells. Knowledge about geology and flowpath structure is incorporated into a model of HES based on a composite approach DFN / heterogeneous continuous medium. Results allow to reproduce satisfactorily the unusual hydraulic behavior of HES, particularly the spatial and time similarity of drawdown curves
Stéphan, Louis. "Modélisation de la ventilation naturelle pour l'optimisation du rafraichissement passif des bâtiments." Chambéry, 2010. http://www.theses.fr/2010CHAMS005.
The spread of mechanical cooling systems resulted in increased power consumption, psychological effects on people and a kind of addiction among occupants Who do not tolerate indoor temperature variations. We are currently witnessing the emergence of a trend pushing towards new standards that recognize the historical adaptive concept. This is actually, in our opinion, the first step towards a sustainable architecture that will manage, in a more respectful way, the integration of buildings in their natural environment. However, there is still a consistent work that needs to be done to enhance our knowledge on natural ventilation in order to achieve optimized control strategies. From our point of view, this will require the development of two types of simulation tools : tools to be used by architects to help make preliminary choices during the design phase where the most important and sometimes irreversible decisions are taken; tools to achieve detailed simulations of air flow patterns in order to validate and refine the basic choice. These tools must be efficient and capable to adapt to any type of construction and change in boundary conditions while preserving a reasonable simulation time. This thesis is built around these two ideas : we proposed a design approach based on the inversion of simplified numerical models in order to size natural ventilation openings. Then, we developed an intermediate more detailed model based on solving Navier-Stokes equations on an adaptive mesh using the method of characteristics and operator's splitting coupled to parallel computing
Hugot, Alexandre. "Modélisation des écoulements gravitaires catastrophiques par une approche objet dynamique : érosion, transport, dépôt." Paris 6, 2000. http://www.theses.fr/2000PA066567.