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High Aspect Ratio Lithographic Imaging at Ultra-high Numerical Apertures: Evanescent Interference Lithography with Resonant Reflector UnderlayersMehrotra, Prateek January 2012 (has links)
A near-field technique known as evanescent interferometric lithography allows for high resolution imaging. However its primary limitation is that the image exponentially decays within the photoresist due to physical limits. This thesis aims to overcome this limitation and presents a method to considerably enhance the depth of focus of images created using evanescent interferometric lithography by using a material underlay beneath the photoresist.
A key enabler of this is the understanding that evanescent fields couple to surface states and operating within proximity of a resonance, the strength of the coupling allows for considerable energy extraction from the incident beam and redistribution of this energy in a photoresist cavity. This led to the analysis of the Fresnel equations, which suggested that such coupling was in fact the result of an enhanced reflectance that takes place at boundaries of carefully chosen materials. While it is known that metals and lossy dielectrics result in surface plasmon polaritons (SPP) and surface exciton polaritons (SEP) as conventional solutions to the Fresnel reflection equations for the TM polarization of light, there is no such naturally occurring surface state that allows evanescent wave enhancement with the TE polarization of light. Further investigation of the Fresnel reflection equations revealed both for TM and TE that in fact another solution exists that is but unconventional to enhance the reflectivity. This solution requires that one of the media have a negative loss. This is a new type of surface resonance that requires that one of the media be a gain medium; not one in the optical pumped sense but one that would naturally supply energy to a wave to make it grow. This new surface resonance is also a key result of this thesis. Clearly, however this is only a hypothetical solution as a real gain medium would violate the conservation of energy.
However, as it is only the reflectance of this gain medium that is useful for evanescent wave enhancement, in fact a multilayered stack consisting of naturally occurring materials is one way to achieve the desired reflectivity. This would of course be only an emulation of the reflectivity aspect of the gain medium. This multilayered stack is then an effective gain medium for the reflectivity purposes when imaging is carried out at a particular NA at a particular wavelength. This proposal is also a key idea of this thesis. At λ = 193 nm, this method was used to propose a feasible design to image high resolution structures, NA = 1.85 at an aspect ratio of ~3.2. To experimentally demonstrate the enhancements, a new type of solid immersion test bed, the solid immersion Lloyd's mirror interference lithography test-bed was constructed. High quality line and space patterns with a half-pitch of 55.5 nm were created using λ = 405 nm, corresponding to a NA of 1.824, that is well in the evanescent regime of light. Image depths of 33-40 nm were seen. Next, the evanescent image was coupled to an effective gain medium made up of a thin layer of hafnium oxide (HfO) upon silicon dioxide (SiO2). This resulted in a considerable depth enhancement, and 105 nm tall structures were imaged.
The work in this thesis details the construction of the solid immersion lithography test-bed, describes the implementation of the modeling tools, details the theory and analysis required to achieve the relevant solutions and understanding of the physical mechanism and finally experimentally demonstrates an enhancement that allows evanescent interferometric lithography beyond conventional limits.
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Submerged landscapes : aesthetics of visual primitivismNicoletti, Martino January 2012 (has links)
This practice-based thesis presents the results of experimental research devoted to ethnic tourism among the Kayan minority and has involved the interconnection of artistic and anthropological languages. Known worldwide for the traditional female custom of wearing a long coiled brass necklace aimed at causing a considerable extension to the neck, the Kayan are a Tibeto-Burman ethnic group originally from Burma. Due to the prolonged civil war in their own homeland, a large number of Kayan recently fled from Burma to refuge in neighbouring Thailand. Here, over the past years, in response to the “incisive” tourism policy promoted by the Thai government in the northern areas of the country, some families, abandoning the refugee camps where they were hosted, have been resettled in several new villages open to tourists, on payment of a modest entrance fee. Here the Kayan, their culture and their daily life, have been transformed into an authentic tourist attraction capable of drawing about 10,000 visitors a year. Founded on a strictly “visual media primitivist” approach and inspired by its peculiar aesthetics – as systematically presented in the first, theoretical, section of the thesis –, the enquiry involves a multimedia perspective. In such a context, analogue photography and filmmaking, creative writing and sound composition have been combined to give concrete shape to an original artwork firmly grounded in ethnographic practice. The choice, far from being a solely arbitrary and subjective option, has indeed been motivated by the critical employment of specific theoretical assumptions of some of the most recent streams of anthropology and epistemology of the human sciences. The multidisciplinary methodology adopted to develop the research, as well as the multifaceted language employed to display its results, represent an innovative and experimental way of approaching the complex theme of cultural identity in present-day Asian contexts, as well as of highlighting the most aesthetic and philosophic implications connected to the revival of analogue vintage media in contemporary artistic practice.
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Variations systématiques dans l’utilisation de l’information du visage, de la prosopagnosie développementale à la super-reconnaissanceTardif, Jessica 08 1900 (has links)
Il existe de grandes variations interindividuelles dans les habiletés pour la reconnaissance des visages. Alors que plusieurs avenues ont été explorées pour expliquer ces variations, leur source reste inconnue. L’utilisation d’information visuelle étant reliée à la performance pour n’importe quelle tâche, l’objectif du projet était d’utiliser la méthode des Bulles pour évaluer comment l’information visuelle utilisée est liée aux habiletés.
Ainsi, les habiletés pour la reconnaissance des visages ont été mesurées chez 107 participants, un large échantillon d’individus normaux provenant du spectre complet d’habiletés, incluant les extrêmes de ce spectre (i.e. prosopagnosie développementale et super-reconnaissance). Ensuite, une tâche de reconnaissance de visages célèbres a été complétée, utilisant la méthode des Bulles pour échantillonner aléatoirement l’information visuelle à chaque essai (1000). Une régression a permis de déterminer quelle information était échantillonnée de façon systématique lors des essais où le participant a répondu correctement. Cette opération résulte en une image de classification pour chaque participant, montrant l’information visuelle utilisée. Enfin, grâce à une régression de deuxième ordre, nous avons pu déterminer quelles sont les régions du visage dont l’utilisation permet de prédire les habiletés dans quatre tâches différentes. Les résultats montrent que 59% de la variation dans les habiletés peut être expliquée grâce à l’utilisation de certaines régions du visage. Plus spécifiquement, plus les participants font usage systématiquement de la région de l’œil gauche du point de vue de l'observateur, plus ils sont habiles. / Abilities for face recognition largely vary among neurotypical individuals. The source of these variations remains largely unknown. Because use of visual information affects performance for a task, the main objective of the project was to better understand the way in which visual information is used affects abilities for face recognition. To this end, we have used the Bubbles method to evaluate use of information in neurotypical participants from the complete spectrum of abilities for face recognition, including extreme cases (developmental prosopagnosics and super-recognizers).
Therefore, face recognition abilities were measured in 107 participants prior to evaluating the visual information they use. In 1000 trials where participants were asked to identify a celebrity’s face, visual information was spatially randomly sampled using the Bubbles method. A regression was then applied between the location of the sampled information and accuracy on each trial, determining which information was systematically sampled when participants correctly identified faces. A second-order regression was then used, which determined the utilization of which regions of the face predicts ability scores, measured in four different tests. Results show that 59% of variations in abilities can be explained by the use of visual information for face recognition. Specifically, the more systematically participants use the region of the left eye, the more accurate they tend to be.
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Po čem dívky touží?: obraz jejich světa v časopisech Super Dívka a BravoGirl! / What girls want? The picture of their world in magazines Super Dívka and BravoGirl!Jebavá, Lucie January 2014 (has links)
The aim of the diploma thesis What do the girls want? The reflection of their world in the magazines Super Dívka and BravoGirl! is to analyze the representation of lifestyle in the magazines for girls and the evolution of this representation within fifteen years. For the needs of this work, the individual theoretical concepts have been discussed, in order to better understand the problematics of media representation of reality. We defined notions such as social and media construction of reality, theory of representation, gender, stereotypes, myths and ideology. Other chapters are dedicated to the notion of lifestyle from its sociological and media perspective, to the girls' magazines themselves and to their up to now researches. These researches are concerned especially with the problematics of consolidation of gender stereotypes in the society through proposed patterns of behaviour and creation of norms of femininity. At the same time, they consider the magazines to be the holders of ideology in consumer and patriarchal society. For the needs of this thesis, the mixed analytical method has been used. The content analysis quantitatively classifies thematic agenda of magazines and semiotic analysis follows denotative and connotative level of signs and their meanings for the representation of...
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Zdaňování příjmů fyzických osob ze závislé činnosti / Taxation of income of natural persons resulting from employmentUhnáková, Zuzana January 2011 (has links)
in English Taxation of individual income tax My diploma thesis contents three major parts, which is divided into smaller articles. In the first part I am trying to present individual income tax in general. Place of income tax in system of taxation and concept of income tax , its function and definition. In another article I described historical evolution of individual income tax and distribution of taxes. To tax is to impose a financial charge or other levy upon a taxpayer (an individual or legal entity) by a state or the functional equivalent of a state such that failure to pay is punishable by law. Taxes consist of direct tax or indirect tax. A tax "is not a voluntary payment or donation, but an enforced contribution, exacted pursuant to legislative authority" and is "any contribution imposed by government. The first known system of taxation was in Ancient Egypt and development is showing us perfection with which we created and improved taxes during the ages. The main second part contents definition of individual income tax by revenue act and determination of basic concepts of individual tax by this act. A personal or individual income tax is levied on the total income of the individual (with some deductions permitted). It is often collected on a pay-as-you-earn basis, with small corrections made...
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Hide and seek : radial-velocity searches for planets around active starsHaywood, Raphaëlle D. January 2015 (has links)
The detection of low-mass extra-solar planets through radial-velocity searches is currently limited by the intrinsic magnetic activity of the host stars. The correlated noise that arises from their natural radial-velocity variability can easily mimic or conceal the orbital signals of super-Earth and Earth-mass extra-solar planets. I developed an intuitive and robust data analysis framework in which the activity-induced variations are modelled with a Gaussian process that has the frequency structure of the photometric variations of the star, thus allowing me to determine precise and reliable planetary masses. I applied this technique to three recently discovered planetary systems: CoRoT-7, Kepler-78 and Kepler-10. I determined the masses of the transiting super-Earth CoRoT-7b and the small Neptune CoRoT-7c to be 4.73 ± 0.95 M⊕ and 13.56 ± 1.08 M⊕, respectively. The density of CoRoT-7b is 6.61 ± 1.72 g.cm⁻³, which is compatible with a rocky composition. I carried out Bayesian model selection to assess the nature of a previously identified signal at 9 days, and found that it is best interpreted as stellar activity. Despite the high levels of activity of its host star, I determined the mass of the Earth-sized planet Kepler-78b to be 1.76 ± 0.18 M⊕. With a density of 6.2(+1.8:-1.4) g.cm⁻³, it is also a rocky planet. I found the masses of Kepler-10b and Kepler-10c to be 3.31 ± 0.32 M⊕ and 16.25 ± 3.66 M⊕, respectively. Their densities, of 6.4(+1.1:-0.7) g.cm⁻³ and 8.1 ± 1.8 g.cm⁻³, imply that they are both of rocky composition – even the 2 Earth-radius planet Kepler-10c! In parallel, I deepened our understanding of the physical origin of stellar radial-velocity variability through the study of the Sun, which is the only star whose surface can be imaged at high resolution. I found that the full-disc magnetic flux is an excellent proxy for activity-induced radial-velocity variations; this result may become key to breaking the activity barrier in coming years. I also found that in the case of CoRoT-7, the suppression of convective blueshift leads to radial-velocity variations with an rms of 1.82 m.s⁻¹, while the modulation induced by the presence of dark spots on the rotating stellar disc has an rms of 0.46 m.s⁻¹. For the Sun, I found these contributions to be 2.22 m.s⁻¹ and 0.14 m.s⁻¹, respectively. These results suggest that for slowly rotating stars, the suppression of convective blueshift is the dominant contributor to the activity-modulated radial-velocity signal, rather than the rotational Doppler shift of the flux blocked by starspots.
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Some contributions to financial market modelling with transaction costs / Quelques contributions à la modélisation des marchés financiers avec coûts de transactionTran, Quoc-Tran 22 October 2014 (has links)
Cette thèse traite plusieurs problèmes qui se posent pour les marchés financiers avec coûts de transaction et se compose de quatre parties.On commence, dans la première partie, par une étude du problème de couverture approximative d’une option Européenne pour des marchés de volatilité locale avec coûts de transaction proportionnelles.Dans la seconde partie, on considère le problème de l’optimisation de consommation dans le modèle de Kabanov, lorsque les prix sont conduits par un processus de Lévy.Dans la troisième partie, on propose un modèle général incluant le cas de coûts fixes et coûts proportionnels. En introduisant la notion de fonction liquidative, on étudie le problème de sur-réplication d’une option et plusieurs types d’opportunités d’arbitrage.La dernière partie est consacrée à l’étude du problème de maximisation de l’utilité de la richesse terminale d’une portefeuille sous contraintes de risque. / This thesis deals with different problems related to markets with transaction costs and is composed of four parts.In part I, we begin with the study of assymptotic hedging a European option in a local volatility model with bid-ask spread.In part II, we study the optimal consumption problem in a Kabanov model with jumps and with default risk allowed.In part III, we sugest a general market model defined by a liquidation procès. This model is more general than the models with both fixed and proportional transaction costs. We study the problem of super-hedging an option, and the arbitrage theory in this model.In the last part, we study the utility maximization problem under expected risk constraint.
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La gouvernance nodale de la sécurité localeQuéro, Yann-Cédric 08 1900 (has links)
No description available.
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Local and Global Analysis of Relaxed Douglas-Rachford for Nonconvex Feasibility ProblemsMartins, Anna-Lena 19 March 2019 (has links)
No description available.
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Approche bayésienne pour la localisation de sources en imagerie acoustique / Bayesian approach in acoustic source localization and imagingChu, Ning 22 November 2013 (has links)
L’imagerie acoustique est une technique performante pour la localisation et la reconstruction de puissance des sources acoustiques en utilisant des mesures limitées au réseau des microphones. Elle est largement utilisée pour évaluer l’influence acoustique dans l’industrie automobile et aéronautique. Les méthodes d’imagerie acoustique impliquent souvent un modèle direct de propagation acoustique et l’inversion de ce modèle direct. Cependant, cette inversion provoque généralement un problème inverse mal-posé. Par conséquent, les méthodes classiques ne permettent d’obtenir de manière satisfaisante ni une haute résolution spatiale, ni une dynamique large de la puissance acoustique. Dans cette thèse, nous avons tout d’abord nous avons créé un modèle direct discret de la puissance acoustique qui devient alors à la fois linéaire et déterminé pour les puissances acoustiques. Et nous ajoutons les erreurs de mesures que nous décomposons en trois parties : le bruit de fond du réseau de capteurs, l’incertitude du modèle causée par les propagations à multi-trajets et les erreurs d’approximation de la modélisation. Pour la résolution du problème inverse, nous avons tout d’abord proposé une approche d’hyper-résolution en utilisant une contrainte de parcimonie, de sorte que nous pouvons obtenir une plus haute résolution spatiale robuste à aux erreurs de mesures à condition que le paramètre de parcimonie soit estimé attentivement. Ensuite, afin d’obtenir une dynamique large et une plus forte robustesse aux bruits, nous avons proposé une approche basée sur une inférence bayésienne avec un a priori parcimonieux. Toutes les variables et paramètres inconnus peuvent être estimées par l’estimation du maximum a posteriori conjoint (JMAP). Toutefois, le JMAP souffrant d’une optimisation non-quadratique d’importants coûts de calcul, nous avons cherché des solutions d’accélération algorithmique: une approximation du modèle direct en utilisant une convolution 2D avec un noyau invariant. Grâce à ce modèle, nos approches peuvent être parallélisées sur des Graphics Processing Unit (GPU) . Par ailleurs, nous avons affiné notre modèle statistique sur 2 aspects : prise en compte de la non stationarité spatiale des erreurs de mesures et la définition d’une loi a priori pour les puissances renforçant la parcimonie en loi de Students-t. Enfin, nous ont poussé à mettre en place une Approximation Variationnelle Bayésienne (VBA). Cette approche permet non seulement d’obtenir toutes les estimations des inconnues, mais aussi de fournir des intervalles de confiance grâce aux paramètres cachés utilisés par les lois de Students-t. Pour conclure, nos approches ont été comparées avec des méthodes de l’état-de-l’art sur des données simulées, réelles (provenant d’essais en soufflerie chez Renault S2A) et hybrides. / Acoustic imaging is an advanced technique for acoustic source localization and power reconstruction using limited measurements at microphone sensor array. This technique can provide meaningful insights into performances, properties and mechanisms of acoustic sources. It has been widely used for evaluating the acoustic influence in automobile and aircraft industries. Acoustic imaging methods often involve in two aspects: a forward model of acoustic signal (power) propagation, and its inverse solution. However, the inversion usually causes a very ill-posed inverse problem, whose solution is not unique and is quite sensitive to measurement errors. Therefore, classical methods cannot easily obtain high spatial resolutions between two close sources, nor achieve wide dynamic range of acoustic source powers. In this thesis, we firstly build up a discrete forward model of acoustic signal propagation. This signal model is a linear but under-determined system of equations linking the measured data and unknown source signals. Based on this signal model, we set up a discrete forward model of acoustic power propagation. This power model is both linear and determined for source powers. In the forward models, we consider the measurement errors to be mainly composed of background noises at sensor array, model uncertainty caused by multi-path propagation, as well as model approximating errors. For the inverse problem of the acoustic power model, we firstly propose a robust super-resolution approach with the sparsity constraint, so that we can obtain very high spatial resolution in strong measurement errors. But the sparsity parameter should be carefully estimated for effective performance. Then for the acoustic imaging with large dynamic range and robustness, we propose a robust Bayesian inference approach with a sparsity enforcing prior: the double exponential law. This sparse prior can better embody the sparsity characteristic of source distribution than the sparsity constraint. All the unknown variables and parameters can be alternatively estimated by the Joint Maximum A Posterior (JMAP) estimation. However, this JMAP suffers a non-quadratic optimization and causes huge computational cost. So that we improve two following aspects: In order to accelerate the JMAP estimation, we investigate an invariant 2D convolution operator to approximate acoustic power propagation model. Owing to this invariant convolution model, our approaches can be parallelly implemented by the Graphics Processing Unit (GPU). Furthermore, we consider that measurement errors are spatially variant (non-stationary) at different sensors. In this more practical case, the distribution of measurement errors can be more accurately modeled by Students-t law which can express the variant variances by hidden parameters. Moreover, the sparsity enforcing distribution can be more conveniently described by the Student's-t law which can be decomposed into multivariate Gaussian and Gamma laws. However, the JMAP estimation risks to obtain so many unknown variables and hidden parameters. Therefore, we apply the Variational Bayesian Approximation (VBA) to overcome the JMAP drawbacks. One of the fabulous advantages of VBA is that it can not only achieve the parameter estimations, but also offer the confidential interval of interested parameters thanks to hidden parameters used in Students-t priors. To conclude, proposed approaches are validated by simulations, real data from wind tunnel experiments of Renault S2A, as well as the hybrid data. Compared with some typical state-of-the-art methods, the main advantages of proposed approaches are robust to measurement errors, super spatial resolutions, wide dynamic range and no need for source number nor Signal to Noise Ration (SNR) beforehand.
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