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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
811

Two-Player Stochastic Games with Perfect and Zero Information / Jeux Stochastiques à Deux Joueurs à Information Parfaite et Zéro

Kelmendi, Edon 02 December 2016 (has links)
On considère des jeux stochastiques joués sur un graphe fini. La première partie s’intéresse aux jeux stochastiques à deux joueurs et information parfaite. Dans de tels jeux, les joueurs choisissent des actions dans ensemble fini, tour à tour, pour une durée infinie, produisant une histoire infinie. Le but du jeu est donné par une fonction d’utilité qui associe un réel à chaque histoire, la fonction est bornée et Borel-mesurable. Le premier joueur veut maximiser l’utilité espérée, et le deuxième joueur veut la minimiser. On démontre que si la fonction d’utilité est à la fois shift-invariant et submixing alors le jeu est semi-positionnel. C’est-à-dire le premier joueur a une stratégie optimale qui est déterministe et sans mémoire. Les deux joueurs ont information parfaite: ils choisissent leurs actions en ayant une connaissance parfaite de toute l’histoire. Dans la deuxième partie, on étudie des jeux de durée fini où le joueur protagoniste a zéro information. C’est-à-dire qu’il ne reçoit aucune information sur le déroulement du jeu, par conséquent sa stratégie est un mot fini sur l’ensemble des actions. Un automates probabiliste peut être considéré comme un tel jeu qui a un seul joueur. Tout d’abord, on compare deux classes d’automates probabilistes pour lesquelles le problème de valeur 1 est décidable: les automates leaktight et les automates simples. On prouve que la classe des automates simples est un sous-ensemble strict de la classe des automates leaktight. Puis, on considère des jeux semi-aveugles, qui sont des jeux à deux joueurs où le maximiseur a zéro information, et le minimiseur est parfaitement informé. On définit la classe des jeux semi-aveugles leaktight et on montre que le problème d’accessibilité maxmin est décidable sur cette classe. / We consider stochastic games that are played on finite graphs. The subject of the first part are two-player stochastic games with perfect information. In such games the two players take turns choosing actions from a finite set, for an infinite duration, resulting in an infinite play. The objective of the game is given by a Borel-measurable and bounded payoff function that maps infinite plays to real numbers. The first player wants to maximize the expected payoff, and the second player has the opposite objective, that of minimizing the expected payoff. We prove that if the payoff function is both shift-invariant and submixing then the game is half-positional. This means that the first player has an optimal strategy that is at the same time pure and memoryless. Both players have perfect information, so the actions are chosen based on the whole history. In the second part we study finite-duration games where the protagonist player has zero information. That is, he gets no feedback from the game and consequently his strategy is a finite word over the set of actions. Probabilistic finite automata can be seen as an example of such a game that has only a single player. First we compare two classes of probabilistic automata: leaktight automata and simple automata, for which the value 1 problem is known to be decidable. We prove that simple automata are a strict subset of leaktight automata. Then we consider half-blind games, which are two player games where the maximizer has zero information and the minimizer is perfectly informed. We define the class of leaktight half-blind games and prove that it has a decidable maxmin reachability problem.
812

Développement d'un outil de simulation multi-échelle adapté au calcul des dommages radio-induits précoces dans des cellules exposées à des irradiations d'ions légers (proton et alpha) / Development of a multi-scale simulation tool for early radio-induced damage assessment in cells exposed to light ions irradiations (proton and alpha)

Meylan, Sylvain 21 October 2016 (has links)
Ce travail de thèse, réalisé dans le cadre des projets de recherche ROSIRIS (IRSN) et Geant4-DNA, porte sur la construction d’une simulation multi-échelle dédiée au calcul des dommages radio-induits précoces à l’ADN qui peuvent apparaître suite à l’irradiation d’un noyau cellulaire. L’outil développé s’appuie sur une version modifiée du code de Monte Carlo Geant4-DNA et est capable de simuler dans le détail le transport et les interactions physiques entre l’irradiation ionisante et la matière biologique (étape physique), la création d’espèces chimiques (étape physico-chimique) et les réactions et processus de diffusion de ces dernières (étape chimique). Durant la simulation de ces trois étapes, un modèle géométrique de l’ADN, décrivant l’ensemble du génome humain avec une précision moléculaire, est généré avec un nouveau logiciel développé dans le cadre de cette thèse : DnaFabric. Les premiers résultats obtenus pour des irradiations avec des protons et des ions alpha sont détaillés et comparés à des données de la littérature. Un bon accord est observés avec ces dernières illustrant ainsi la cohérence de l’ensemble de la simulation. L’influence très significative du critère de sélection utilisé pour identifier les dommages à l’ADN est également démontrée. / This work was performed in the frame of the ROSIRIS (IRSN) and Geant4-DNA research projects and describes the development of a simulation tool to compute radioinduced early DNA damages in a cell nucleus. The modeling tool is based on a modified version of the Monte Carlo code Geant4-DNA and is able to simulate the physical interactions between ionizing particles and the biological target (physical stage), the creation of chemical species within the cell nucleus (physico-chemical stage) as well as the reactions and diffusion processes of these chemical species (chemical stage). During all the simulation, a geometrical model that describes the DNA content of a human diploid cell nucleus is taken into account. This model was generated with a new software (DnaFabric) developed in the frame of this work and has a molecular level of detail.The first results (in term of DNA strand breaks) obtained with this tool are detailed and compared with experimental data from the literature. The good agreement between the simulation results and those data shows the coherence of our modeling. The significant influence of the selection criteria used to identify the DNA damages is also demonstrated.
813

Comportement hydromécanique et érosion des sols fins traités / Hydro-mechanical behavior and erosion of fine tread soils

Mehenni, Abdelwadoud 15 December 2015 (has links)
L’évolution actuelle du contexte socio-économique oblige les différents acteurs du secteur des travaux publics à s’adapter aux problématiques du développement durable. Dans le domaine des ouvrages en terre, les entreprises doivent proposer des solutions techniques de valorisation des matériaux situés dans l’emprise des projets afin de limiter les emprunts extérieurs et la mise en dépôt des sols non utilisés. Les techniques de traitement des sols constituent une possibilité de valoriser ces matériaux. Cette étude se focalise sur quatre produits de traitement (kaolinite, bentonite, chaux et ciment) ainsi que sur leurs effets sur le comportement hydromécanique et la résistance à l’érosion interne d’un limon fin. Un dispositif d’érosion interne HET optimisé a été spécialement conçu dans le cadre de ce travail pour déterminer les caractéristiques d’érosion des sols traités notamment à la chaux et au ciment. Au-delà de la caractérisation des effets du traitement sur le comportement hydromécanique à court terme des sols, le travail de cette étude s’étend sur la durabilité des traitements et l’évolution du comportent hydromécanique à long terme des sols traités soumis à des sollicitations hydriques de séchage-humidification. Cette étude de la durabilité est effectuée à travers une approche multi-échelle fondée sur des données d’études en laboratoire sur des éprouvettes de sol traité et des investigations in situ sur des ouvrages hydrauliques en sol traité. L’étude montre que les sollicitations hydriques peuvent dégrader les performances du sol traité. Cette dégradation se traduit par une augmentation de la conductivité hydraulique, une diminution de la résistance mécanique et aussi une diminution de la contrainte critique qui exprime une diminution de la résistance à l’érosion interne. La cinétique de perte de performances est conditionnée par la nature du produit de traitement et son dosage utilisé, et aussi par le niveau d’exposition, le nombre et l’intensité des cycles hydriques. Cependant, l’étude in situ montre qu’il est possible de diminuer la cinétique de dégradation des performances de sols à travers des dispositions constructives adaptées. / The current evolution of the social and economic context requires from the different actors of the public works sector to adapt their practices to the challenges of sustainable development. In the field of earthworks, companies must offer technical solutions to reuse the materials located in the vicinity of the projects in order to limit the borrowing materials and unused soils deposits. Soil treatment may allow the reuse of these materials. This study was focused on four treatment products (kaolinite, bentonite, lime and cement) as well as their effects on the hydro-mechanical behavior and internal erosion resistance of a fine silt. An enhanced HET device was designed in the framework of this study to determine the internal erosion characteristics of treated soils especially with lime and cement. Beyond the characterization of treatment effects on short-term hydro-mechanical behavior of soils, the work of this study extends to the durability of treatment and the evolution of long-term hydro-mechanical behavior of treated soils subjected to drying-wetting cycles. This study of sustainability was carried out through a multi-scale approach based on laboratory study data on soil samples and field investigations on hydraulic structures made of treated soil. The study showed that hydraulic conditions variations can decrease the performance of treated soils. These degradations result on an increase in hydraulic conductivity, a decrease of the mechanical strength and also a reduction in the critical shear stress which expresses a decrease of the internal erosion resistance. The kinetic of performance loss depends to the nature of the treatment product and percentage used as well as the exposure level, the number and amplitude of the hydraulic variations. However, the field study showed that it is possible to reduce the kinetic degradation of the soil performance through an appropriate construction design.
814

Spatially Adaptive Analysis and Segmentation of Polarimetric SAR Data

Wang, Wei January 2017 (has links)
In recent years, Polarimetric Synthetic Aperture Radar (PolSAR) has been one of the most important instruments for earth observation, and is increasingly used in various remote sensing applications. Statistical modelling and scattering analysis are two main ways for PolSAR data interpretation, and have been intensively investigated in the past two decades. Moreover, spatial analysis was applied in the analysis of PolSAR data and found to be beneficial to achieve more accurate interpretation results. This thesis focuses on extracting typical spatial information, i.e., edges and regions by exploring the statistical characteristics of PolSAR data. The existing spatial analysing methods are mainly based on the complex Wishart distribution, which well characterizes the inherent statistical features in homogeneous areas. However, the non-Gaussian models can give better representation of the PolSAR statistics, and therefore have the potential to improve the performance of spatial analysis, especially in heterogeneous areas. In addition, the traditional fixed-shape windows cannot accurately estimate the distribution parameter in some complicated areas, leading to the loss of the refined spatial details. Furthermore, many of the existing methods are not spatially adaptive so that the obtained results are promising in some areas whereas unsatisfactory in other areas. Therefore, this thesis is dedicated to extracting spatial information by applying the non-Gaussian statistical models and spatially adaptive strategies. The specific objectives of the thesis include: (1) to develop reliable edge detection method, (2) to develop spatially adaptive superpixel generation method, and (3) to investigate a new framework of region-based segmentation. Automatic edge detection plays a fundamental role in spatial analysis, whereas the performance of classical PolSAR edge detection methods is limited by the fixed-shape windows. Paper 1 investigates an enhanced edge detection method using the proposed directional span-driven adaptive (DSDA) window. The DSDA window has variable sizes and flexible shapes, and can overcome the limitation of fixed-shape windows by adaptively selecting homogeneous samples. The spherically invariant random vector (SIRV) product model is adopted to characterize the PolSAR data, and a span ratio is combined with the SIRV distance to highlight the dissimilarity measure. The experimental results demonstrated that the proposed method can detect not only the obvious edges, but also the tiny and inconspicuous edges in heterogeneous areas. Edge detection and region segmentation are two important aspects of spatial analysis. As to the region segmentation, paper 2 presents an adaptive PolSAR superpixel generation method based on the simple linear iterative clustering (SLIC) framework. In the k-means clustering procedure, multiple cues including polarimetric, spatial, and texture information are considered to measure the distance. Since the constant weighting factor which balances the spectral similarity and spatial proximity may cause over- or under-superpixel segmentation in different areas, the proposed method sets the factor adaptively based on the homogeneity analysis. Then, in heterogeneous areas, the spectral similarity is more significant than the spatial constraint, generating superpixels which better preserved local details and refined structures. Paper 3 investigates another PolSAR superpixel generation method, which is achieved from the global optimization aspect, using the entropy rate method. The distance between neighbouring pixels is calculated based on their corresponding DSDA regions. In addition, the SIRV distance and the Wishart distance are combined together. Therefore, the proposed method makes good use of the entropy rate framework, and also incorporates the merits of the SIRV distance and the Wishart distance. The superpixels are generated in a homogeneity-adaptive manner, resulting in smooth representation of the land covers in homogeneous areas, and well preserved details in heterogeneous areas. / <p>QC 20171123</p>
815

The choice of capital budgeting techniques : a human capital approach

Levin, Victoria, Hallgren, Anna January 2017 (has links)
Tidigare forskning har identifierat ett gap mellan teori och hur företag använder kapitalbudgeteringstekniker i praktiken. Forskning tyder på att gapet är särskilt stort vid SME-företag, eftersom de tenderar att använda de enkla kapitalbudgeteringsteknikerna. Genom att försöka förklara förekomsten av fenomenet the theory-practice gap  har forskare reflekterat kring vilka bakomliggande faktorer som ligger till grund för valet av kapitalbudgeteringsteknik i SME-företag. En bakomliggande faktor som påverkar valet av kapitalbudgeteringsteknik är en individs humankapital, i form av utbildningsnivå och yrkeserfarenhet. Syftet med denna studie är att undersöka hur humankapitalet påverkar valet av kapitalbudgeteringsteknik vid strategiska investeringar i svenska SME-företag. För att undersöka och analysera studiens syfte har en kvantitativ datainsamlingsmetod använts i form av en internetbaserad enkät. Studien har en positivistisk forskningsfilosofi som utgår från en deduktiv forskningsansats som används för att möjliggöra hypotesprövningar. Studiens resultat baseras på 56 respondenter vilka är beslutfattare vid strategiska investeringar i svenska SME-företag, där resultaten illustreras med hjälp av statistiska analysmetoder. Studiens resultat och slutsats visar att beslutfattare i svenska SME-företag med högre utbildningsnivå eller högre grad av yrkeserfarenhet ökar användningen av avancerade kapitalbudgeteringstekniker. Dock kan inte studiens resultat signifikant påvisa att en beslutsfattare i svenska SME-företag med låg utbildningsnivå eller lägre grad av yrkeserfarenhet använder enkla kapitalbudgeteringstekniker. / Previous research has identified a gap between theory and how companies actually use capital budgeting techniques in practice. Research highlights that the gap is particularly large among SMEs, as they tend to use simpler capital budgeting techniques. By trying to explain the phenomenon of the theory-practice gap, researchers have reflected on underlying factors that influence the choice of capital budgeting techniques in SMEs. An underlying factor, that influences the choice of capital budgeting techniques, is on the individual level in terms of educational degree and occupational level of experience. The aim of this thesis is therefore to increase the understanding of how the human capital influences the choice of capital budgeting techniques in Swedish SMEs. To examine the aim of the study, a quantitative method is used by a web-based survey. Furthermore, the study is based on a positivism research philosophy that evolve from a deductive research method in order to draw general conclusions. The result of the study is based on 56 responses from decision makers for strategic investments in Swedish SMEs, where the results are illustrated using statistical analysis methods. The results and conclusions of the study shows that decision makers in Swedish SMEs with higher degree of education or higher level of occupational experience increase the use of more advanced capital budgeting techniques. However, the results do not support that decision makers in Swedish SMEs with a lower degree of education or lower level of occupational experience use more simple capital budgeting techniques.
816

Modélisations et inversions des diagrammes de diffusion particulaire enregistrés par un photodétecteur organique conformable / Size distribution of particle systems analyzed with organic photodetectors

Sentis, Matthias 12 December 2014 (has links)
Dans le cadre d'un consortium entre centres de recherche publics et industriels, ce travail de thèse de doctorat s'est attaché à démontrer l'intérêt des détecteurs photo-organiques (OPS) pour la caractérisation des suspensions et écoulements diphasiques. Les principes de plusieurs granulomètres permettant la caractérisation de ces milieux lorsqu'ils sont confinés dans une cuve cylindrique transparente (configuration standard du Process Analytical Technology) ont été proposés. Pour évaluer et optimiser les performances de ces systèmes, un code de simulation de type Monte-Carlo a été spécifiquement développé. Ce dernier permet de prendre en compte les nombreux paramètres du problème comme le profil du faisceau laser, les différentes surfaces spéculaires composant le montage, la composition du milieu particulaire (concentration, diamètre moyen, écart-type, matériau,...), la forme et la position des OPS. Les propriétés de diffusion des particules sont traitées à l'aide des théories de Lorenz-Mie et de Debye, de même qu'un modèle hydride prenant en compte les contributions géométriques et physiques. Pour les milieux dilués (diffusion simple), l'analyse repose sur l'inversion des diagrammes de diffusion obtenus sur une large plage angulaire ou au voisinage de singularités optiques remarquables (arc-en-ciel, diffusion critique, diffraction). Pour les milieux denses (diffusion multiple), les pistes étudiées reposent sur l'analyse des caractéristiques de la tache de rétrodiffusion. / As part of a consortium between academic and industry, this PhD work investigates the interest and capabilities of organic photo-sensors (OPS) for the optical characterization of suspensions and two-phase flows. The principle of new optical particle sizing instruments is proposed to characterize particle systems confined in a cylinder glass (standard configuration for Process Analytical Technologies). To evaluate and optimize the performance of these systems, a Monte-Carlo model has been specifically developed. This model accounts for the numerous parameters of the system: laser beam profile, mirrors, lenses, sample cell, particle medium properties (concentration, mean & standard deviation, refractive indices), OPS shape and positions, etc. Light scattering by particles is treated either by using Lorenz-Mie theory, Debye, or a hybrid model (that takes into account the geometrical and physical contributions). For diluted media (single scattering), particle size analysis is based on the inversion of scattering diagrams obtained over a wide angular range or near optical singularities (rainbow, critical scattering, diffraction). For dense media (multiple scattering), the solutions foreseen are based on the analysis of the backscattering spotlight characteristics.
817

Kyvadlo nejen z pohledu střední školy / Pendulum not only from the high school point of view

Chamrová, Martina January 2021 (has links)
The diploma thesis is divided into five chapters. The first chapter is devoted to the history and usage of pendulums with focus on the development of measurement of time and gravitational acceleration. The second chapter deals with the concept of pendulum from a theoretical perspective at all levels of the Czech educational system, including a research in textbooks, collection of questions and problems, and scientific articles. In the third chapter, the results of the research of sources of inspiration for simple real- life experiments, applets and simulations, and laboratory work are presented. The fourth chapter is focused on the theoretical background of the four selected models of pendulums, and the last chapter is devoted to simple experiments with these selected models. For each experiment, a videorecording is available on the enclosed DVD. This thesis is suitable for all physics teachers, as well as for students of teaching physics. However, it may also serve as a motivation for students in optional courses of high school physics. 1
818

Využívání odpadního tepla / Heat recovery

Dužík, Vojtěch January 2018 (has links)
The aim of this diploma thesis is to theoretically, practically and experimentally explore different ways of waste heat utilization in the building industry. The work is divided into three basic passages. In the first part I analyze the theoretical nature of the various physical processes in recovery and is there a practical use. More emphasis is placed on heat recovery from wastewater, as I am using this way of recuperation in other parts of this diploma thesis. In the second point, I apply the use of heat from waste water when designing a technical solu-tion for the reconstruction of the heating system of the clinic. The design is solved in two variants. The first suggested location lokali- them, recuperative, shower exchanger operation rehabilitation, bath and massage. In the second variant, central recovery is envisaged using a heat exchanger in the accumulator well and water-water heat pump. Based on the technical and economic evaluation, the first option was selected. The second variant is ineffective and remains only in the case study. In the last section, I experimentally investigate the thermal efficiency and the relative savings of the heat exchanger, which is designed in the first variant of the second part. Measurement, processing of results and evaluation I made for laboratory conditions and for real conditions with the showering person. Finally, I appreciate the eco-nomic benefits of this facility.
819

Realizace útoku na maskovaný šifrovací algoritmus / Power analysis attack on masked AES implementation

Jakubíková, Radka January 2015 (has links)
The cryptographic algorithms are commonly used as a security item today. In some situations, the special device is used to run the cryptographic algorithm, so the data are protected against the attack from the internet. Naturally, the attack can be loaded on the device as well using the side channel attack. The data are under the great danger, because nowadays plenty of power consumption analyses exist. The side channel attack uses knowledge about the cryptographic algoritm and simple or differential analysis. The diploma thesis focuses on the differential power analysis attack for the data published under the DPA contest. This thesis covers different types of analyss and attacks, and describes the new DPACv4.2 implementation. The correlation analysis is presented for the DPACv4.2 and the possible attack is discussed at the conclusion.
820

Obchodní galerie / Shopping Gallery

Žák, Ondřej January 2014 (has links)
Master's thesis addresses the design and assessment of the load bearing structure of the shopping gallery. The building is designed as a three-storey rectangular plan with a flat roof. The structure is composed of steel frames and composite steel and concrete slabs. There are proposed two possible solutions - variant with a flat roof and direct central gallery, a reinforced rigid steel frames and a variant with a cupola roofed circular inner atrium, solidified with rods.

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