Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-07T19:46:54Z No. of bitstreams: 1 sebastiaomaurofilho.pdf: 422464 bytes, checksum: 2d72827356c924e509ef415cf17ff6bc (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-06-26T17:47:29Z (GMT) No. of bitstreams: 1 sebastiaomaurofilho.pdf: 422464 bytes, checksum: 2d72827356c924e509ef415cf17ff6bc (MD5) / Made available in DSpace on 2017-06-26T17:47:29Z (GMT). No. of bitstreams: 1 sebastiaomaurofilho.pdf: 422464 bytes, checksum: 2d72827356c924e509ef415cf17ff6bc (MD5) Previous issue date: 2012-02-29 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Recentemente foi demonstrado [17] que correções quânticas para o potencial gravitacional de Newton explica as curvas de rotação em galáxias espirais sem introduzir o halo de matéria escura. O único parâmetro fenomenológico aѵ da teoria cresce com a massa da galáxia. A fim de melhor investigar a dependência de aѵ com a massa é preciso verificar o limite superior para aѵ em uma escala menor. Aqui nós realizamos o cálculo correspondente por meio da análise da dinâmica do vetor de Laplace-Runge-Lenz e da condição de equilíbrio de anãs-brancas. A limitação resultante sobre correções quânticas sugerem uma dependência de aѵ com a massa. / Recently it was shown that quantum corrections to the Newton potential can explain the rotation curves in spiral galaxies without introducing the Dark Matter halo. The unique phenomenological parameter aѵ of the theory grows with the mass of the galaxy. In order to better investigate the mass-dependence of aѵ one needs to check the upper bound for aѵ at a smaller scale. Here we perform the corresponding calculation by analyzing the dynamics of the Laplace-Runge-Lenz vector and the equilibrium condition of white-dwarf. The resulting limitation on quantum corrections is suggesting a mass-dependence of aѵ.

This thesis examines the relationship between price expectations and current consumption. Especially, whether the postponement of final consumption expenditure by households, as a result of their declining price expectations; which may be a deflatively-recessive spiral starter; coincides with economic theory and practice. Based on this, appropriate economic policy recommendations can be drawn. The analysis in the framework of intertemporal consumer model of two periods extended by inflation and the risk confirms this hypothesis. Price expectations positively affect current consumption through the intertemporal substitution effect of real interest rate changes. However, certain assumptions must be fulfilled. Especially, the economy must be in a fixed nominal interest rate environment, the substitution effect must not be offset by the effect of a change in the expected real disposable income or the income effect of the change in the real interest rate and the households must have a higher disposable income so that they can afford to postpone consumption. These findings coincide with the conclusions of the empirical analyzes mentioned in this thesis.

This report covers an investigation of the methods and algorithms required to plan and perform semi-autonomous photo missions on Apple iPad devices using data exported from Google Earth. Flight time was to be minimized, taking wind velocity and aircraft performance into account. Google Earth was used both to define what photos to take, and to define the allowable mission area for the aircraft. A benchmark mission was created containing 30 photo operations in a 250 by 500 m area containing several no-fly-areas. The report demonstrates that photos taken in Google Earth can be reproduced in reality with good visual resemblance. High quality paths between all possible photo operation pairs in the benchmark mission could be found in seconds using the Theta* algorithm in a 3D grid representation with six-edge connectivity (Up, Down, North, South, East, West). Smoothing the path in a post-processing step was shown to further increase the quality of the path at a very low computational cost. An optimal route between the operations in the benchmark mission, using the paths found by Theta*, could be found in less than half a minute using a Branch-and-Bound algorithm. It was however also found that prematurely terminating the algorithm after five seconds yielded a route that was close enough to optimal not to warrant running the algorithm to completion.

Cette thèse présente les travaux effectués au CELIA sur la luminescence ultraviolette et les dynamiques excitoniques dans l’oxyde de zinc (ZnO) sous forme massive et nano-structurée. Les mesures ont été effectuées en conditions expérimentales contrôlées (température, fluence d’excitation), pour différentes énergies de photon excitateur. Nous avons mesuré les spectres d’émission sous excitation à un photon UV (4,66 eV), ainsi que à 3 photons IR (1,55 eV), et proposé un schéma séquentiel de formation des excitons (avec simulations), en particulier pour les excitons DX. Nous avons obtenu une durée de vie nanoseconde de DX dans les deux cas, en désaccord avec la majorité des études publiées dans la littérature. / This thesis presents the work carried out at CELIA about ultraviolet luminescence and exciton dynamics in massive and nano-structured zinc oxide (ZnO). Measurements were carried out under controlled experimental conditions (temperature, excitation fluence), according to different excitation photon energies.We measured emission spectra under UV photon excitation (4.66 eV), and 3 IR photons (1.55 eV), and suggested a sequential exciton formation mechanism (with simulations), especially for DX excitons. We found a nanosecond lifetime for DX in both cases, in disagreement with most of the studies published in the literature. Relaxation dynamics of free and bound excitons are linked by the FX trapping process on donor defect and the DX thermal detrapping.Under VUV excitation (20-50 eV), surface effects and strong local excitation density greatly accelerate the relaxation of excitons. Under X excitation (1 keV), good conditions for the formation of DX seems to be close under excitation at 1.55 and 950 eV.The presence of core 2p band of zinc modifies the relaxation dynamics of excitons by the multiplication of local high density excitations zones and the change of the elementary excitations distribution. We have also conducted measurements on nano-particles. The significant surface effects induced by the small size of these system lead to a sharp acceleration of kinetics, masking the intrinsic exciton relaxation process.

Contemporary terrorism is becoming increasingly indiscriminate, and rail bound traffic appears to be vulnerable and at high risk for terrorist attacks. An attack targeting a train or subway system can have enormous implications, both in terms of human suffering and long-term societal consequences. This dissertation aims to analyze how public and private organizations prepare for and respond to crises emanating from terrorism targeting rail bound traffic. It also examines different practices, networks and ideas related to interorganizational collaboration. Contemporary research emphasizes the importance and advantages of collaborative action in crisis management, and the idea of inter-organizational collaboration is also embedded in policy documents and has support among practitioners. Despite this, interorganizational collaboration often turns out to be difficult in practice, and it stands out as a critical factor in many crisis situations. Hence, it is crucial to identify and better understand the challenges associated with interorganizational collaboration in the context of terrorist-induced crises. This dissertation is a contribution to this endeavor. In order to capture the inherent complexity of the topic this dissertation combines and merges literature from three research fields: crisis management research, disaster medicine research and terrorism studies. The dissertation examines international experiences of terrorist attacks directed against rail bound traffic. It identifies the way in which attacks have changed over time and analyzes the main challenges of providing pre-hospital care following a mass-casualty attack. In addition, Sweden is used to provide empirical focus in an analysis of preparedness. Relying on scenario-based interviews with central crisis management actors and actors from rail bound traffic, current preparedness practices for responding to a multi-site terrorist attack on rail bound traffic in Sweden is analyzed. The research shows that both public and private organizations have developed risk awareness about terrorist-induced crises. However, their preparedness practices are characterized by significant variations and substantial uncertainty. Scare resources are a critical factor, and actors find it difficult to invest in preparedness for seldom-occurring crises. This difficulty is accentuated by the fact that no major mass-casualty attack has taken place in Sweden. A terrorist attack differs from a routine event and poses new and different challenges for inter-organizational collaboration. A large number of organizations are supposed to work together under severe time constraints, and their work can be delayed by particular security concerns. It is assumed that rail bound traffic actors engage in collaborative crisis management; however, there appear to be few mechanisms to prepare them, in a systematic way, for managing this particular type of crisis. Among actors, inter-organizational collaboration is understood primarily from a normative view rather than from the point of view of its practical meaning. As a consequence, it is difficult to turn risk awareness and a commitment to working together into actual practical action. In addition, collaboration between different levels in the crisis management system is particularly challenging. This dissertation also identifies a tension between viewing crisis management as an example of policy-as-usual or from a crises-as-exceptions perspective.

The goal of this thesis is to design a suitable method for lossy compression of heightmap terrain data. This method should accept blocks of float samples of dimensions 2^n x 2^n as an input, for which it should be able to perform progressive decompression of mip-maps (lower-resolution representations). It should keep the reconstructed data within a certain maximum per-sample error bound for each mip-map level. This bound should be in the unit of meters and adjustable by the user. Given these constraints, it should be as efficient as possible. Our method is inspired by the second generation of progressive wavelet-based compression scheme modified to satisfy the~maximum-error constraint. We simplified this scheme by factoring out unnecessary computations in order to improve the efficiency. Our method can compress a 256x256 block in about 30 ms and decompress it in about 2 ms. Thanks to these attributes, the method can be used in a real-time planet renderer. It achieves the compression ratio of 37:1 on the whole Earth 90m/sample terrain dataset transformed and separated into square blocks, while respecting the maximum error of 5m. Powered by TCPDF (www.tcpdf.org)

Cette étude s'inscrit dans le domaine de la surveillance de l'environnement. Elle consiste à optimiser et valider la procédure analytique de détermination du tritium sous forme organique, et à identifier les molécules organiques, porteuses de tritium, responsables de son transfert de l'environnement à l'homme. La démarche s'est organisée en trois temps. Une procédure analytique a d'abord été mise en place pour déterminer, la teneur en hydrogène des échantillons, élément clé, utilisée pour le calcul des activités de tritium organique. L'impact de la séparation des fractions de tritium organique (l'échange labile) sur la détermination de l'activité de la fraction représentative du niveau de tritium environnemental a ensuite été évalué. Pour cela, les quantités d'échantillon solubilisées ont été estimées. Enfin, la spéciation du tritium dans des échantillons environnementaux a été abordée. Pour cela, les familles de molécules, puis les composés organiques solubilisés lors des échanges labiles ont été identifiés. Les résultats montrent que la répartition du tritium dans les organismes dépend à la fois des propriétés de la liaison chimique dans laquelle il est impliqué et des propriétés des molécules organiques le portant. Les composés identifiés appartiennent aux familles de molécules constitutives (glucides, acides aminés) de la matière vivante. Il serait à présent intéressant d'étudier la répartition du tritium au sein d'un échantillon de l'environnement pour cibler les molécules d'intérêt et étudier de manière plus approfondie la distribution du tritium dans l'environnement et son impact, de l'environnement à l'homme. / This study deals with environmental monitoring. The main aims are (i) the optimisation of the analytical procedure for the tritium in organic form determination, and (ii) the identification of the tritium bearing molecules which are responsible for its transfer from the environment to man. The study was divided into three stages. First an analytical method was developed to determine hydrogen content of several samples, which is a key element to calculate accurate organically bound tritium activities. Secondly, the impact of the organically bound tritium fractions separation (labile exchange) for the determination of the representative fraction of the level of environmental tritium activity was then evaluated. For that, the amount of solubilised sample was estimated. Finally, the speciation of tritium in environmental samples was investigated. Several molecules classes and organic compounds dissolved in the labile exchanges solvent were identified. The results show that the distribution of tritium in organisms depends on both properties of the chemical bond in which it is involved and chemical properties of tritium bearing molecules. The identified compounds belong to the molecules classes such as carbohydrates or amino acids, constitutive of living organisms. It would now be of interest to study the tritium distribution in an environmental sample to target molecules of interest and study the impact of tritium from the environment to man.

In this dissertation, we examine specific network connectivity problems, and achieve improved approximation algorithm and integrality gap results for them. We introduce an important new, highly useful and applicable, network connectivity problem - the Vital Core Connectivity Problem (VCC). Despite its many practical uses, this problem has not been previously studied. We present the first constant factor approximation algorithm for VCC, and provide an upper bound on the integrality gap of its linear programming relaxation. We also introduce a new, useful, extension of the minimum spanning tree problem, called the Extended Minimum Spanning Tree Problem (EMST), that is based on a special case of VCC; and provide both a polynomial-time algorithm and a complete linear description for it. Furthermore, we show how to generalize this new problem to handle numerous disjoint vital cores, providing the first complete linear description of, and polynomial-time algorithm for, the generalized problem. We examine the Survivable Network Design Problem (SNDP) with multiple copies of edges allowed in the solution (multi-SNDP), and present a new approximation algorithm for which the approximation guarantee is better than that of the current best known for certain cases of multi-SNDP. With our method, we also obtain improved bounds on the integrality gap of the linear programming relaxation of the problem. Furthermore, we show the application of these results to variations of SNDP. We investigate cases where the optimal values of multi-SNDP and SNDP are equal; and we present an improvement on the previously best known integrality gap bound and approximation guarantee for the special case of SNDP with metric costs and low vertex connectivity requirements, as well as for the similar special case of the Vertex Connected Survivable Network Design Problem (VC-SNDP). The quality of the results that one can obtain for a given network design problem often depends on its integer linear programming formulation, and, in particular, on its linear programming relaxation. In this connection, we investigate formulations for the Steiner Tree Problem (ST). We propose two new formulations for ST, and investigate their strength in terms of their associated integrality gaps.

Le tritium est l’isotope radioactif de l’hydrogène. Il est capable d’intégrer la plupart des moléculesbiologiques. Bien que sa radiotoxicité soit faible, les effets du tritium seraient augmentés s’il étaitcapable de se concentrer dans des compartiments critiques du vivant. Afin de mieux comprendre lacirculation du tritium dans l’environnement et mettre en évidence les constantes de transfert entrecompartiments, nous avons étudié la tritiation de différentes matrices agricoles exposéeschroniquement à du tritium. La première étape de notre démarche est la validation des techniquesmises en oeuvre dans la préparation des échantillons. Nous avons démontré la possibilité de stocker deséchantillons environnementaux à Valduc et avons mis en évidence différents biais liés à l’extraction del’eau. Des solutions ont été proposées. Une hypothèse est formulée sur l’origine physique du facteurde séparation isotopique original que nous avons mis en évidence lors de l’extraction de l’eau du lait.Dans l’étude environnementale, les mesures faites sur les végétaux confirment l’importance del’exposition atmosphérique dans la tritiation de la plante. L’absence de différence liée à l’espèce dansla tritiation de la matière sèche a été démontrée. La diversité des résultats obtenus sur la tritiation desdifférentes fractions de matrices végétales encouragent la poursuite de cette voie de recherche. Nousavons comparé la tritiation des principales fractions hydrogénées du lait, d’abord entre elles puis entreéchantillons afin de mettre en évidence les facteurs à l’origine des différences observées. Nous avonsainsi montré la très grande corrélation entre l’eau d’abreuvement et l’eau libre du lait ainsi qu’entre lesactivités tritium de la matière sèche du bol alimentaire et des fractions organiques du lait. Nous avonségalement mis en évidence l’importance des paramètres métaboliques dans l’excrétion du tritium dansle lait. La synthèse de ces résultats montre l’importance des effets de la dilution de l’hydrogène dansles compartiments considérés devant les mécanismes de discrimination isotopique, y compris au seind’une chaîne alimentaire exposée chroniquement dans son ensemble. / Tritium is the radioactive isotope of hydrogen. It can be integrated in most of the biological molecules.Even if its radiotoxicity is weak, effects of tritium could be increased if it can concentrate in somecritical compartments of beings. In order to better understand the tritium circulation in the environment and highlight constants of transfer between compartments, we have studied the tritiationof different agricultural matrices chronically exposed to tritium. The first step of our study is thevalidation of the different techniques used to prepare our sample. We have also demonstrated that itwas possible to store environmental samples in the Valduc centre and have underlined some biasesdue to the extraction of free water. Some ways of improvements are proposed. A hypothesis has alsobeen formulated on the origin of an original isotopic fractionation effect during the extraction of the free water of milk. In the environmental study, the specific activities measured on plants confirm the importance of the atmospheric exposure on their tritiation. No difference in the tritiation has beenmeasured between wheat, barley and colza. Some differences have been measured in the tritiation ofsome organic components of vegetal matrices. These results underline the interest of continuing thiskind of study. We have also compared the tritiation of the main hydrogenated components of milk,first, component to component, then, sample to sample. Some origins of the measured differences havebeen shown. We have demonstrated the correlation between the specific activities of drinking waterand the free water of milk as between the tritiations of dry matter of cattle’s food and of the mainorganic components of milk. Our results show also the importance of the metabolism on thedistribution of tritium in the different compartments. The overall synthesis of our results show the importance of the dilution of hydrogen in the considered environmental compartments, above theisotopic effects, even in a food chain chronically exposed to tritium.

This thesis deals with CNB interventions in favor of the exchange rate depreciation of November 2013. The theoretical part presents alternative tools for unconventional monetary policy when zero lower bound is binding. This thesis then describes the experience of other central banks that responded to low interest rates. Intervention of CNB is contextualized in the Czech financial system and previous economic development. The thesis analyses alternative instruments which CNB might have accessed. Based on the analyzed data this thesis concludes that despite the long-term maintenance of weakened Koruna above the level of announced exchange rate pledge the sufficiently loose monetary policy was not translated into desired price increase.