Fluctuations in accommodation have been shown to be correlated in the two eyes of the same subject. However, the dynamic correlation of higher-order aberrations in the frequency domain has not been studied previously. A binocular Shack-Hartmann wavefront sensor is used to measure the ocular wavefront aberrations concurrently in both eyes of six subjects at a sampling rate of 20.5 Hz. Coherence function analysis shows that the inter-ocular correlation between aberrations depends on subject, Zernike mode and frequency. For each subject, the coherence values are generally low across the resolvable frequency range (mean 0.11), indicating poor dynamic correlation between the aberrations of the two eyes. Further analysis showed that phase consistency dominates the coherence values. Monocular and binocular viewing conditions showed similar power spectral density functions.

Made available in DSpace on 2016-06-02T20:27:38Z (GMT). No. of bitstreams: 1 3160.pdf: 1167165 bytes, checksum: d968da16f55a4ed2bbefe667a52d3d80 (MD5) Previous issue date: 2010-08-17 / Financiadora de Estudos e Projetos / In this work, we studied the construction of weak solutions for some systems conservation laws and for a scalar conservation laws For the p-systems relativistic we use the Wave-front tracking based on Bressan, when the total variation of the initial data is locally bounded. We construct is somewhat more simpler than in methods studied by other authors. For the equation of Aw-Rascle we apply the method of Glimm and the method Wave-front tracking, we consider the appearence of the vacuum, when the total variation of the initial data is locally bounded. For the scalar conservation law we study the construction of admissible weak solutions using the Glimm method and the poligonal approximations. / Neste trabalho, estudamos a construção de soluções fracas para alguns sistemas de leis de conservação e para uma lei de conservação escalar. Para o p-sistema relativístico aplicamos o método Wave-front tracking baseado em Bressan, quando a variação total do dado inicial é localmente limitada. O nosso método de construção é um pouco mais simples que os métodos estudados por outros autores. Para as equações de Aw-Rascle aplicamos o método de Glimm e o método Wave-front tracking permitindo ou não o aparecimento de vácuo nas soluções aproximadas, quando a variação total do dado inicial é localmente limitada. Para a lei de conservação escalar estudamos a construção de soluções fracas admissíveis utilizando o método de Glimm e a aproximação poligonal.

Using data from the frequency disturbance recorders (FDRs) that comprise the nation-wide frequency monitoring network known as FNET, disturbances in the eastern interconnected system (EI) have been monitored and recorded over the past several years. Analysis of this and other data by a wide variety of research scientists and engineers has rendered the idea that frequency disturbances from generator trips, transmission line trips, load trips, and other events, travel with finite speed as electromechanical waves throughout any power system (in this case the EI). Using FNET data as a tool, it is possible to measure and output the arrival times of these disturbance waves with a time resolution of 100 ms. To observe with certainty the arrival time of the frequency disturbance waves, field data collected by the FDRs must first be conditioned in a robust manner. The current method that uses the moving mean of raw FDR data is analyzed and two computationally efficient robust methods are suggested in this report. These new methods that rely on robust statistics are more resistant to the effect of outliers contained within the raw FDR data. Furthermore, like the moving mean, these methods smooth the raw data without removing the general trend. Having recorded and conditioned the FDR data, three conventional triangulation techniques taken from the field of seismology are proposed and analyzed. This study reconfirms the fact that the EI is not a medium of continuous elasticity though which the frequency perturbations travel but rather a discontinuous patchwork of varying elasticities. Within this report, nine generator trip events are analyzed and the aforementioned triangulation methods are applied. The advantages and disadvantages of each method are discussed. To conclude, axioms of future research are proposed and delineated. / Master of Science

Le besoin tant en haute qualité d'imagerie qu'en structures légères est l'un des principaux moteurs pour la conception des télescopes spatiaux. Un contrôle efficace du front d'onde va donc devenir indispensable dans les futurs grands observatoires spatiaux, assurant une bonne performance optique tout en relâchant les contraintes sur la stabilité globale du système. L'optique active consiste à contrôler la déformation des miroirs, cette technique peut être utilisée afin de compenser la déformation des grands miroirs primaires, afin de permettre l'utilisation d'instrument reconfigurable ou afin de fabriquer des miroirs asphériques avec le polissage sous contraintes. Dans ce manuscrit, la conception de miroirs actifs dédiés à l'instrumentation spatiale est présentée. Premièrement, un système compensant la déformation d'un grand miroir allégé dans l'espace est conçu et ses performances sont démontrées expérimentalement. Avec 24 actionneurs, le miroir MADRAS (Miroir Actif Déformable et Régulé pour Applications Spatiales) effectuera une correction efficace du front d'onde dans un relais de pupille du télescope. Deuxièmement, un harnais de déformation pour le polissage sous contraintes des segments du télescope géant européen de 39 m (E-ELT) est présenté. La performance du procédé est prédite et optimisée avec des analyses éléments finis et la production en masse des segments est considérée. Troisièmement, deux concepts originaux de miroirs déformables avec un nombre minimal d'actionneurs ont été développés. VOALA (Variable Off-Axis parabola) est un système à trois actionneurs et COMSA (Correcting Optimized Mirror with a Single Actuator) est un système à un actionneur. / The need for both high quality images and light structures is one of the main driver in the conception of space telescopes. An efficient wave-front control will then become mandatory in the future large observatories, ensuring the optical performance while relaxing the specifications on the global system stability. Consisting in controlling the mirror deformation, active optics techniques can be used to compensate for primary mirror deformation, to allow the use of reconfigurable instruments or to manufacture aspherical mirror with stress polishing. In this manuscript, the conception of active mirrors dedicated to space instrumentation is presented. Firstly, a system compensating for large lightweight mirror deformation in space, is designed and its performance are experimentally demonstrated. With 24 actuators, the MADRAS mirror (Mirror Actively Deformed and Regulated for Applications in Space) will perform an efficient wave-front correction in the telescope's pupil relay. Secondly, a warping harness for the stress polishing of the 39 m European Extremely Large Telescope segments is presented. The performance of the process is predicted and optimized with Finite Element Analysis and the segments mass production is considered. Thirdly, two original concepts of deformable mirrors with a minimum number of actuators have been developed. The Variable Off-Axis parabola (VOALA) is a 3-actuators system and the Correcting Optimized Mirror with a Single Actuator (COMSA) is a 1-actuator system.

In this paper, we present a nonlinear curvelet-based sparsity-promoting formulation for three problems in seismic processing and imaging namely, seismic data regularization from data with large percentages of traces missing; seismic amplitude recovery for subsalt images obtained by reverse-time migration and primary-multiple separation, given an inaccurate multiple prediction. We argue why these nonlinear formulations are beneficial.

L'observation directe des exoplanètes est rendue difficile par l'énorme contraste entre la planète et l'étoile autour de laquelle elle gravite, ainsi que la faible séparation angulaire entre ces deux corps. Un tel niveau de contraste aussi proche de l'étoile être atteint en couplant l'imagerie à haute résolution angulaire et la coronographie, qui atténue le flux en provenance de l'étoile ; les performances ultimes d'un instrument d'imagerie à haut contraste sont alors limitées par ses aberrations quasi-statique. Au cours de cette thèse a été conçu un ASO plan focal dédié à la calibration des aberrations quasi-statiques dans les systèmes d'imagerie à haut contraste. Cet ASO, baptisé COFFEE, permet d'estimer les aberrations en amont et en aval du coronographe à partir d'images coronographiques acquises en plan focal différant d'une phase de diversité connue introduite en amont du coronographe. Au cours de cette thèse, COFFEE a été conçu et validé par simulations numérique et démontré expérimentalement sur banc. L'identification de plusieurs facteurs limitant la précision de l'estimation des aberrations a ensuite induit une modification du formalisme sur lequel repose COFFEE pour l'adapter à l'estimation d'aberrations de hautes fréquences spatiales avec une précision nanométrique. Cette version hauts ordres de COFFEE a été utilisée avec succès sur l'instrument SPHERE, où la compensation des aberrations estimées par COFFEE a permis d'optimiser le contraste. Enfin, une nouvelle méthode de compensation a été développée pour permettre d'atteindre de très hauts niveaux de contraste sur le détecteur scientifique. / Performing an exoplanet direct detection means being able to image an object as faint as an extra-solar planet very close to its parent star. After compensation of the turbulence by the XAO loop and most of the star light removed by a coronagraph, the ultimate limitation of high contrast imaging systems lies in its quasi-static aberrations that creates a residual signal which limit the achievable contrast on the scientific detector. To increase the achievable contrast on the detector, these aberrations must be compensated for, ideally using focal plane data recorded from the scientific detector to avoid differential aberrations. The aim of this thesis was to develop a focal-plane wavefront sensor (WFS) dedicated to the estimation of quasi-static aberrations in high contrast imaging systems. This WFS, called COFFEE, estimates the aberrations both upstream and downstream of the coronagraph using coronagraphic focal plane images that differ from a known diversity aberrations introduced upstream of the coronagraph. During this research work, COFFEE has been developed, tested using numerical simulations and demonstrated on an in-house bench. Considering the limitations of the estimation accuracy, COFFEE's formalism has then been modified to allow it to estimate high frequencies aberrations with nanometric precision. This extended version of COFFEE has been successfully used on SPHERE to optimize the contrast on the scientific detector of the instrument using COFFEE in a dedicated compensation process. Lastly, a new compensation method has been developed in order to reach very high contrast levels on the scientific detector.

L'Europe prépare actuellement le plus grand télescope du monde : l'European Extremely Large Telescope (E-ELT). Prévu vers 2026, ce télescope géant permettra de répondre à des questions fondamentales de l'astrophysique contemporaine. L'imagerie d'objets astrophysiques depuis des télescopes au sol est cependant perturbée par l'atmosphère qui réduit la capacité des instruments au sol à distinguer les objets proches. L'Optique Adaptative (OA) permet de restaurer cette résolution angulaire en corrigeant en temps réel (via un miroir déformable) le front d'onde perturbé par l'atmosphère (mesuré par l'Analyseur de Surface d'Onde (ASO)). Jusqu'à récemment, la majorité des systèmes d'OA utilisaient des ASO Shack-Hartmann (SH). Des concepts concurrents basés sur le filtrage optique de Fourier (le senseur Pyramide ou l'analyseur Zernike) viennent cependant d'être mis en fonctionnement et leurs résultats semblent surpasser les performances du SH. En vue de leur potentielle utilisation sur les ELTs, cette thèse vise à consolider leur compréhension théorique ainsi qu'à optimiser ces ASO basés sur le filtrage de Fourier. Cette thèse développe un cadre mathématique qui décrit sous un unique formalisme ces ASO. Il permet de généraliser les designs préexistants -passant ainsi d'ASO uniques à des "classes d'ASO"- en transformant leurs grandeurs caractéristiques à l'origine fixées en degrés de liberté. Les classes Pyramide et Zernike sont donc explorées dans le but d'optimiser ces ASO au regard des attentes expérimentales. Des configurations inédites de la classe Pyramide -ASO que l'on appelle Pyramides aplaties- s'avèrent notamment prometteuses et font l'objet d'une étude plus poussée. / Europe is currently preparing the largest telescope of the world: the European Extremely Large Telescope (E-ELT). Planned by 2026, this huge telescope will allow to answer fundamental questions of contemporary astrophysics. However, images of astrophysical objects done by ground based telescopes suffer from the atmospheric turbulence which reduces the capacity of instruments to distinguish objects too close to each other. The Adaptive Optics (AO) allows to restore this loss of angular resolution by correcting (thanks to a deformable mirror) in real time the perturbed wave front (measured by the WaveFront Sensor (WFS)).Until very recently, the majority of AO systems had used the Shack-Hartmann (SH) WFS. New concepts based on Fourier filtering (the Pyramid or the Zernike WFSs) have however just been put in operation in several professional observatories and their results seem to outperform the SH. Since they would potentially be chosen for the AO systems of the future ELTs, this thesis aims to consolidate their theoretical understanding and to optimize these Fourier based WFSs.We firstly develop a mathematical framework which describes all these WFSs under an unique formalism. It allows to generalize the pre-existent designs -a WFS thus becomes a "WFS class"- by considering their optical parameters as flexible quantities. We then explored the two Pyramid and Zernike classes to identify the influence of class' parameters on performance criteria in order to optimize optical designs with regard to the instrumental requirements. New configurations of the Pyramid class -that we called Flattened pyramids- show promising behaviors and are studied in details.

3-dimensional imaging often requires substantial effort since information along the optical axis is not straight forward gatherable. In many applications it is aimed for depth information along the direction of view. For example fluidic mixing processes and the environmental interaction on a microscopic scale are of particular importance for e.g. pharmaceutical applications and often demand for 3D information. This problem is often solved by stereoscopic approaches, where two cameras are used in order to gather depth information by triangulation technique. Another approach is to scan the object through the focal plane in order to get sharp images of each layer. Since the before mentioned approaches require a lot of video data to be evaluated it would be more convenient to get depth mapping within a single camera recording and without scanning. Here we present a tunable 3D depth-mapping camera technique in combination with dynamic aberration control. By using an incoherent light source, only one camera and a spatial light modulator (LCoS-SLM), it is a simply applicable and highly scalable technique. A double-helix point spread function (DH-PSF) is generated for light emerging from the bserved focal plane. Each object appears as a double-image on the camera. Within the orientation of the double-image, depth information along the optical axis is encoded. By using an additional adaptive element (deformable mirror) the technique is combined with wide-field aberration correction. Here we combine a tunable 3D depth camera with dynamic aberration control in one imaging system.

<p>U doktorskoj disertaciji posmatrani su Rimanovi problemi kod strogo i slabo hiperboličnih&nbsp;nelinearnih sistema PDJ. U uvodu je predstavljena jednačina zakona održanja u jednoj prostornoj&nbsp;dimenziji i definisani su Ko&scaron;ijevi i Rimanovi problemi. U drugoj glavi, date su osnovne osobine&nbsp;nelinearnih hiperboličnih zakona održanja, uvedeni supojmovi stroge hiperboličnosti i slabog re&scaron;enja&nbsp;zakona održanja. Definisani su Rankin-Igono i entropijski uslovi kao i op&scaron;te re&scaron;enje Rimanovog problema&nbsp;(za dovoljno male početne uslove). U trećoj glavi detaljno je obja&scaron;njena Glimova diferencna &nbsp;&scaron;ema. Metod&nbsp;praćenja talasa predstavljen je u četvrtoj glavi. Pokazano je da se ovom metodom, za dovoljno male&nbsp;početne uslove, dobija stabilno i jedinstveno re&scaron;enje koje u svakom vremenu ima ograničenu totalnu&nbsp;varijaciju. U petoj glavi, posmatrana je jednačina protoka izentropnog gasa u Lagranžovim koordinatama.&nbsp;Uz pretpostavku da je početni uslov ograničen i da ima ograničenu totalnu varijaciju, pokazano je da&nbsp;Ko&scaron;ijev problem ima jedinstveno slabo re&scaron;enje ako je totalna varijacija početnog uslova pomnožena sa &nbsp;0&lt;&epsilon;&lt;&lt; 1 dovoljno mala. Slabo re&scaron;enjedobijeno je metodom praćenja talasa. U glavi &scaron;est ispitana je&nbsp;interakcija dva delta talasa koji su posmatrani kao specijalna vrsta shadowtalasa. U glavi sedam,&nbsp;pokazano je da za proizvoljno velike početne uslove, re&scaron;enje Rimanovog problema jednodimenzionalnog&nbsp;Ojlerovog zakona održanja gasne dinamikepostoji, daje jedinstveno i entropijski dopustivo, uz drugačiju<br />ocenu snaga elementarnih talasa. Data je numerička verifikacija interakcije dva delta talasa kori&scaron;ćenjem&nbsp;metode praćenja talasa.</p> / <p>In this doctoral thesis, Riemann problems for strictly and weakly nonlinear hyperbolic PDE&nbsp;systems were observed. In the introduction, conservation laws in one spatial dimension were presented&nbsp;and the Cauchy and Riemann problems were defined. In the second chapter, the basic properties of&nbsp;nonlinear hyperbolic conservation laws were intorduced, as well as the terms such as strictly hyperbolic&nbsp;system and weak solution of conservation law. Also, Rankine -Hugoniot and entropy conditions were<br />introduced and the general solution to the Riemann problem (for sufficiently small initial conditions) were&nbsp;defined. Glimm&rsquo;s difference scheme was explained in the third chapter. The wave front tracking method&nbsp;was introduced in the fourth chapter. It was shown that, using this method, for sufficiently small initial&nbsp;conditions, it could be obtained a unique solution with bounded total variation for t &ge;0. In the fifth&nbsp;chapter, the Euler equations for isentropic fluid inLagrangian coordinates were observed. Under the&nbsp;assumption that the initial condition was bounded and had bounded total variation, it was shown that the&nbsp;Cauchy problem had a weak unique solution, provided that the total variation of initial condition&nbsp;multiplied by 0&lt;&epsilon;&lt;&lt;1 was sufficiently &nbsp;small. Weak solution was obtained by applying the wave front&nbsp;tracking method. In the sixth chapter, the interaction of two delta shock waves were examined. Delta&nbsp;shock waves were regarded as special kind of shadowwaves. In the chapter seven, it was shown that for&nbsp;arbitrarily large initial conditions, solution to the Riemann problem of one-dimensional Euler&nbsp;conservation laws of gas dynamics existed, it was unique and admissible. New bounds on the strength of&nbsp;elementary waves in the wave front tracking algorithm were given. The numerical verification of two&nbsp;delta shock waves interaction via wave front tracking method was given at the end of the thesis.</p>

<p>We introduce a family of smooth functions which are &quot;less regu-lar&quot; than the Gevrey functions, and study its basic properties. In particular&nbsp;we prove the standard results concerning algebra property and stability under finite order derivation. Moreover, we &nbsp;construct infnite order operators&nbsp;which leads us to the definition of class with ultradifferentiable property. We&nbsp;also prove that our classes are inverse-closed, and this result is the essential&nbsp;part in the proof of our main result presented in the final Chapter. Moreover,&nbsp;using the techniques of microlocal analysis, we introduce and investigate the<br />corresponding wave front sets, and the prove the results related to singular&nbsp;support of a distribution. Our main results shows how the singularities of&nbsp;solutions to partial differential equations (PDE&#39;s in short) propagate in the&nbsp;framework of our regularity.</p> / <p>U ovoj tezi defini&scaron;emo novu klasu glatkih funkcija i izučavamo njihove osnovne osobine. Pokazujemo da na&scaron;e klase imaju svojsto algebre kao i da su zatvorene u odnosu na delovanje operatora izvoda konačnog reda.Sta vi&scaron;e, konstrui&scaron;emo diferencijalne operatore beskonačnog reda i to nas dovodi do definicije ultradiferencijabilnih klasa funkcija. Takode dokazujemo osobinu zatvorenosti u odnosu na inverze, i taj rezultat je najvažniji deo u dokazu glavne teoreme koja je formulisana u poslednjoj glavi. Koristeći tehnike mikrolokalne analize, uvodimo i izučavamo odgovarajuće talasne frontove, i pokazujemo odgovarajuća tvrdjenja vezana za singularni nosač distribucije. Na&scaron; glavni rezultat pokazuje kako se prostiru singulariteti re&scaron;enja linearnih parcijalnih diferencijalnih jednačina u okviru na&scaron;e regularnosti.</p>