This Master's thesis analyses business results of the entrepreneurial subject. The Master's thesis includes the fundamental analysis and the strategical analysis. On the basis of these analyses I propose the suggestions leading to the stability and perspective entrepreneurial activities.

Des systèmes avec des coefficients dépendant du retard ont été rencontrés dans diverses applications de la science et de l'ingénierie. Malgré la littérature abondante sur les systèmes de temporisation, il y a peu de résultats concernant l'analyse de stabilité des systèmes avec des coefficients dépendant du retard. Cette thèse est consacrée à l'analyse de stabilité de cette classe de systèmes.Les méthodes d'analyse de la stabilité sont développées à partir de l'équation caractéristique correspondante suivant une approche généralisée tau-décomposition. Étant donné un intervalle d'intérêt de retard, nous sommes capables d'identifier toutes les valeurs de retard critique contenues dans cet intervalle pour lesquelles l'équation caractéristique admet des racines sur l'axe imaginaire du plan complexe. Le critère de direction de croisement des racines sont proposées pour déterminer si ces racines caractéristique se déplacent vers le plan complexe demi-gauche ou demi-droite lorsque le paramètre de retard passe par ces valeurs de retard critique. Le nombre de racines caractéristiques instables pour un retard donné peut ainsi être déterminé. Notre analyse comprend les systèmes avec un seul retard ou des retards proportionnés sous certaines hypothèses. Le critère de direction de croisement des racines développés dans cette thèse peut être appliqués aux multiple racines caractéristiques, ou aux racines caractéristiques dont la position paramétrée par le retard est tangent à l'axe imaginaire. En tant qu'application, il est démontré que les systèmes avec des coefficients dépendant du retard peuvent provenir de schémas de contrôle qui utilisent une sortie retardée pour approcher ses dérivés pour la stabilisation. Les méthodes d'analyse de stabilité développées dans cette thèse sont adaptées et appliquées pour trouver les intervalles de retard qui atteignent un taux de convergence demandé du système en boucle fermée. / Systems with delay-dependent coefficients have been encountered in various applications of science and engineering. However, general and systematic stability analysis is rarely reported in the rich literature on time-delay systems. This thesis is committed to the stability analysis of such class of systems.Stability analysis methods are developed based on the corresponding characteristic equation following a generalized tau-decomposition approach. Given a delay interval of interest, we are able to identify all the critical delay values contained in this interval for which the characteristic equation admits roots on the imaginary axis of the complex plane. Various root crossing direction criteria are proposed to determine whether these characteristic roots move toward the left or the right half complex plane as the delay parameter sweeps through these critical delay values. The number of unstable characteristic roots for any given delay can thus be determined. Our analysis covers systems with a single delay or commensurate delays under certain assumptions. The root crossing direction criteria developed in this thesis can be applied to characteristic roots with multiplicity, or characteristic roots whose locus parametrized by the delay is tangent to the imaginary axis. As an application, it is demonstrated that systems with delay-dependent coefficients can arise from control schemes that use delayed output to approximate its derivatives for stabilization. The stability analysis methods developed in this thesis are tailored and applied to find the delay intervals that achieve a demanded convergence rate of the closed-loop system.

<div>This research consists of the development of a new educational tool for calculations of 2D slope stability problems, named PNW-SLOPE. Slope stability has been considered one of the most important topics in geotechnical engineering for many years, so this is a subject which students should build a good background in the university. This program was created in Microsoft Excel with the aid of VBA (Visual Basic for Applications). The use of VBA allowed the creation of a good user interface, therefore those who are using the program can easily follow the instructions to create, analyze the model and check the results. Even though there are many commercial programs with the same application, this research presents a new alternative, more focused on educational purposes. PNW-SLOPE is divided in several modules.The first consists of the geometry definition of the slope. The second module consists of a deterministic slope stability analysis considering limit equilibrium method and the method of slices. The third module consists of a probability analysis considering Monte Carlo simulation. With these two options, users can compare both analysis and understand how important is the consideration of probability analysis in Geotechnical Engineering. This is a pertinent topic nowadays, since reliability analysis is increasingly being incorporated in standards and design codes throughout the world. An additional module was created for rock slope stability problems in which the failure results from sliding on a single planar surface dipping into the excavation. Several examples are presented to demonstrate some of the features of PNW-SLOPE and results are verified with commercial programs such as Geostudio Slope/w and Rocscience Slide 2018.</div>

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / In this research, an improved first order formulation is presented to study the critical buckling load in functionally graded beams. The formulation has five independent variables in comparison with the Timoshenko theory that has three. The Trefftz criterion is utilized with incremental and fundamental states to define the stability analysis. Virtual work statements are derived for the finite element model where the field variables are interpolated by Lagrange polynomials. The numerical results are compared and verified with other formulations found in literature. Parametric studies are also carried out for buckling behavior due to different slenderness ratios, power-law indices and boundary conditions. Applications of the model to functionally graded materials show the validity of the present approach.

The increase in antibiotic resistance continues to pose a public health risk as very few new antibiotics are being produced, and bacteria resis- tant to currently prescribed antibiotics is growing. Within a typical hospital setting, one may find patients colonized with bacteria resistant to a single an- tibiotic, or, of a more emergent threat, patients may be colonized with bacteria resistant to multiple antibiotics. Precautions have been implemented to try to prevent the growth and spread of antimicrobial resistance such as a reduction in the distribution of antibiotics and increased hand washing and barrier pre- ventions; however, the rise of this resistance is still evident. As a result, there is a new movement to try to re-examine the need for the development of new antibiotics. In this paper, we use mathematical models to study the possible benefits of implementing a new antibiotic in this setting; through these models, we examine the use of a new antibiotic that is distributed in various ways and how this could reduce total resistance in the hospital. We compare several dif- ferent models in which patients colonized with both single and dual-resistant bacteria are present, including a model with no additional treatment proto- cols for the population colonized with dual-resistant bacteria as well as models including isolation and/or treatment with a new antibiotic. We examine the benefits and limitations of each scenario in the simulations presented.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20917号 / 理博第4369号 / 新制||理||1627(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 嶺重 慎, 准教授 前田 啓一, 教授 太田 耕司 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24390号 / 理博第4889号 / 新制||理||1699(附属図書館) / 京都大学大学院理学研究科数学・数理解析専攻 / (主査)教授 大木谷 耕司, 教授 並河 良典, 准教授 竹広 真一 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

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[pt] A estabilidade de encostas constituídas por solos residuais não saturados sofre grande influência das variações das condições de fluxo locais, uma vez que, em muitos casos, grande parte de sua resistência ao cisalhamento é conferida pela coesão aparente acarretada pelo fenômeno de sucção. Sabendo disso, o presente trabalho avaliou, através de análises de estabilidade e de fluxo realizadas em modelos bi e tridimensionais, a possibilidade de se criar um modelo onde o resultado final de estabilidade independa da distribuição de sucção inicial. As análises e modelagens de fluxo e estabilidade foram executadas com auxílio dos softwares SVDesigner, SVSlope e SVFlux-GE integrantes do pacote SVoffice, desenvolvido pela SoilVision. Buscou-se quantificar a influência da distribuição da sucção inicial nos casos estudados. Os parâmetros de solo utilizados como dados de entrada nos modelos derivaram de estudos desenvolvidos por de Oliveira (2013) sobre os mecanismos de ruptura de movimentos de massa que ocorreram em Nova Friburgo durante o megadesastre que ocorreu na Região Serrana do Rio de Janeiro em 2011, e os dados climáticos advieram de registros contemporâneos e pretéritos ao evento. Nos modelos 2D foi possível, ao se considerar aproximadamente oito meses de dados climáticos, que diferentes condições iniciais de sucção homogêneas convergissem para um resultado único de estabilidade. Nas modelagens também foi observado que o comportamento do fluxo diferiu entre os modelos 2D e 3D o que teve um significativo impacto em suas análises de estabilidade. / [en] The stability of slopes consisting of unsaturated residual soils is strongly influenced by variations in local flow conditions, since in many cases much of their shear strength is conferred by the apparent cohesion caused by the suction phenomenon. With this in mind, the present study evaluated the possibility of creating a model where the final stability result is independent of the initial suction distribution through stability and flow analyzes performed in two and three-dimensional models. Flow and stability analyzes and modeling were performed using the SVDesigner, SVSlope and SVFlux-GE software components of the SVoffice package developed by SoilVision. It was tried to quantify the influence of the initial suction distribution in the cases studied. The soil parameters used as input data in the models were derived from studies developed by de Oliveira (2013) on the mechanisms of rupture of the mass movements that occurred in Nova Friburgo during the disaster that occurred in the Serrana Region of Rio de Janeiro in 2011, and the climatic data came from records in the region during and before the event. In the 2D models, it was possible, considering approximately eight months of climatic data, that different initial homogeneous suction conditions converged to a single stability result. It was also observed that the flow behavior differed between the 2D and 3D models, which had a significant impact on their stability analyzes.