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This dissertation develops a variety of structure-preserving algorithms for mechanical systems with external forcing and also extends those methods to systems that evolve on non-Euclidean manifolds. The dissertation is focused on numerical schemes derived from variational principles – schemes that are general enough to apply to a large class of engineering problems. A theoretical framework that encapsulates variational integration for mechanical systems with external forcing and time-dependence and which supports the extension of these methods to systems that evolve on non-Euclidean manifolds is developed. An adaptive time step, energy-preserving variational integrator is developed for mechanical systems with external forcing. It is shown that these methods track the change in energy more accurately than their fixed time step counterparts. This approach is also extended to rigid body systems evolving on Lie groups where the resulting algorithms preserve the geometry of the configuration space in addition to being symplectic as well as energy and momentum-preserving. The advantages of structure-preservation in the numerical simulation are illustrated by various representative examples from engineering applications, which include limit cycle oscillations of an aeroelastic system, dynamics of a neutrally buoyant underwater vehicle, and optimization for spherical shape correlation and matching. / Doctor of Philosophy / Accurate numerical simulation of dynamical systems over long time horizons is essential in applications ranging from particle physics to geophysical fluid flow to space hazard analysis. In many of these applications, the governing physical equations derive from a variational principle and their solutions exhibit physically meaningful invariants such as momentum, energy, or vorticity. Unfortunately, most traditional numerical methods do not account for the underlying geometric structure of the physical system, leading to simulation results that may suggest nonphysical behavior. In this dissertation, tools from geometric mechanics and computational methods are used to develop numerical integrators that respect the qualitative features of the physical system. The research presented here focuses on numerical schemes derived from variational principles– schemes that are general enough to apply to a large class of engineering problems. Energy-preserving algorithms are developed for mechanical systems by exploiting the underlying geometric properties. Numerical performance comparisons demonstrate that these algorithms provide almost exact energy preservation and lead to more accurate prediction. The advantages of these methods in the numerical simulation are illustrated by various representative examples from engineering applications, which include limit cycle oscillations of an aeroelastic system, dynamics of a neutrally buoyant underwater vehicle, and optimization for spherical shape correlation and matching.

The goal of this Thesis is to give a presentation of some key issues regarding the non-perturbative renormalization of the periodic scalar field theories. As an example of the non-perturbative methods, we use the differential renormalization group approach, particularly the Wegner-Houghton and the Polchinski renormalization group equations, in order to investigate the renormalization of a one-component periodic scalar field theory. The Wegner-Houghton equation provides a resummation of the loop-expansion, and the Polchinski equation is based on the resummation of the perturbation series. Therefore, these equations are exact in the sense that they contain all quantum corrections. In the framework of these renormalization group equations, field theories with periodic self interaction can be considered without violating the essential symmetry of the model: the periodicity. Both methods - the Wegner-Houghton and the Polchinski approaches - are inspired by Wilson's blocking construction in momentum space: the Wegner-Houghton method uses a sharp momentum cut-off and thus cannot be applied directly to non-constant fields (contradicts with the "derivative expansion"); the Polchinski method is based on a smooth cut-off and thus gives rise naturally to a "derivative expansion" for varying fields. However, the shape of the cut-off function (the "scheme") is not fixed a priori within Polchinski's ansatz. In this thesis, we compare the Wegner--Houghton and the Polchinski equation; we demonstrate the consistency of both methods for near-constant fields in the linearized level and obtain constraints on the regulator function that enters into Polchinski's equation. Analytic and numerical results are presented which illustrate the renormalization group flow for both methods. We also briefly discuss the relation of the momentum-space methods to real-space renormalization group approaches. For the two-dimensional Coulomb gas (which is investigated by a real-space renormalization group method using the dilute-gas approximation), we provide a systematic method for obtaining higher-order corrections to the dilute gas result.

Rural Extension in Brazil has passed through many transformations in its way of acting and developing the work with farmers. The extension methods are extremely related to these transformations and, in a large extent, since the creation of the official services of Rural Extension, they arethe identity of the extensionist institutionsworker in the country.This study has analyzed the use of different methods of rural extension by the Empresa de Pesquisa de Agropecuária e Extensão Rural Santa Catarina (Epagri). The research was developed through the case study of the Unidade de GestãoTécnica 5, composed by 31 cities, located in the region called Alto Vale do Itajaí SC, with a cuali-quantative approach.The results point out that, in relation to the nature of the work done by extensionists, there is a predominance of office activities over field work, determined, mainly, by the demand of the paper work generated by governmental programs. The data demonstrated that about 50% of the farmers and 40% of the actions developed are associated to back activities, showing that a big part of the technician`s effort is associated to the demand of governmental programs. Considering the nature of the work methods, it was founda predominance of individual approach technics, they constitute 94.54% of the activities unfolded, existing among them a predominance of the office visiting. According to the technicians‟ point of view, the predominance of the individual approach is related to the nature of the work that they do and, the changes implemented in the Epagri managementdid not produced the expected effects in the increasing use of group methods. / A Extensão Rural no Brasil tem passado por diversas transformações na sua forma de atuar e desenvolver o trabalho junto aos agricultores. Os métodos de extensão guardam estreitas relações com essas transformações e em grande medida continuam sendo, desde a criação dos serviços oficias de Extensão Rural, a identidade do trabalhador das instituições extensionistas no país. Este estudo analisou o emprego dos diferentes métodos de extensão rural pela Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina (Epagri). A pesquisa foi desenvolvida a partir do estudo de caso da Unidade de Gestão Técnica 5, composta por 31 municípios, situada na região denominada Alto Vale do Itajaí - SC, com uma abordagem quali-quantitativa. Os resultados apontam que, em relação à natureza do trabalho desenvolvido pelos extensionistas, ocorre um predomínio das atividades de escritório sobre o trabalho de campo, determinado em grande medida pela demanda do trabalho burocrático gerado pelos programas governamentais. Os dados demonstraram que praticamente 50% dos agricultores e 40% das ações desenvolvidas vinculam-se às atividades de apoio, apontando que grande parte do esforço dos técnicos está relacionada com as demandas dos programas governamentais. Em relação à natureza dos métodos de trabalho, constatou-se um predomínio absoluto das técnicas de abordagem individual, que constituem 94,54% das atividades realizadas, havendo entre elas uma ampla predominância dos atendimentos no escritório. Na visão dos técnicos, o predomínio dos métodos de abordagem individual está relacionado à natureza do trabalho que desenvolvem e as mudanças implantadas na gestão da Epagri não surtiram os efeitos desejados no aumento do emprego de métodos de caráter grupal.

The purpose of this exploratory study is to develop alternative models for analyzing the systems dynamics of a large group conference format called appreciative inquiry (AI) summits. I apply Luhmann’s social systems theory to the strategizing activities of AI summits to examine how this particular format is capable of generating organizational knowledge. An AI summit is a strategic planning conference in which hundreds of internal and external stakeholders collectively design the future of the organization through structured activities. It applies the principles of AI, a consulting method used in organizational development that attends to the positive aspects of an organization as opposed to its problems. Critics challenge this unconditional focus on the positive, questioning the validity of its methods and techniques. Indeed, very few rigorous evaluations of AI methods including AI summits exist. I propose a new approach for assessing the effectiveness of AI summits. I focus on knowledge creation as the dependent variable. Previous studies have shown that successful AI interventions generate new knowledge, not just transformational change. I conceptualize an AI summit as a strategic episode that allows an organization to temporarily suspend its routines and structures for strategic reflection. According to social systems theory, organizations are autopoietic (self-reproducing) systems that maintain their identity through an ongoing production of decision communications. An AI summit consists of three different types of systems that co-evolve and are structurally coupled: an organization system, interaction system and the individual participants’ psychological systems. I propose a typology for analyzing episodes during an AI summit as a starting point for determining the structural dynamics inherent in an AI summit system. Using illustrative examples from a case study, I identify five structural features of an AI summit that facilitate organizational knowledge creation, including reduced communication barriers and the production of decisions during the conference. The study contributes to the existing literature by identifying the important but understudied role of self-organizing project teams in the knowledge creation process at an AI summit. Limitations and implications are discussed.

The goal of this Thesis is to give a presentation of some key issues regarding the non-perturbative renormalization of the periodic scalar field theories. As an example of the non-perturbative methods, we use the differential renormalization group approach, particularly the Wegner-Houghton and the Polchinski renormalization group equations, in order to investigate the renormalization of a one-component periodic scalar field theory. The Wegner-Houghton equation provides a resummation of the loop-expansion, and the Polchinski equation is based on the resummation of the perturbation series. Therefore, these equations are exact in the sense that they contain all quantum corrections. In the framework of these renormalization group equations, field theories with periodic self interaction can be considered without violating the essential symmetry of the model: the periodicity. Both methods - the Wegner-Houghton and the Polchinski approaches - are inspired by Wilson's blocking construction in momentum space: the Wegner-Houghton method uses a sharp momentum cut-off and thus cannot be applied directly to non-constant fields (contradicts with the "derivative expansion"); the Polchinski method is based on a smooth cut-off and thus gives rise naturally to a "derivative expansion" for varying fields. However, the shape of the cut-off function (the "scheme") is not fixed a priori within Polchinski's ansatz. In this thesis, we compare the Wegner--Houghton and the Polchinski equation; we demonstrate the consistency of both methods for near-constant fields in the linearized level and obtain constraints on the regulator function that enters into Polchinski's equation. Analytic and numerical results are presented which illustrate the renormalization group flow for both methods. We also briefly discuss the relation of the momentum-space methods to real-space renormalization group approaches. For the two-dimensional Coulomb gas (which is investigated by a real-space renormalization group method using the dilute-gas approximation), we provide a systematic method for obtaining higher-order corrections to the dilute gas result.

The master's thesis deals with the issue of consolidated financial statement. The first part of the master's thesis contains the theoretical basis for the preparation of the consolidated financial statements. Subsequently, the theoretical knowledge is applied to the practical part of the master's thesis, which deals with the preparation of the consolidated financial statements of the analyzed entity.

Esse estudo propôs-se avaliar presença de transtornos de eixo I, personalidade e caracterizar demograficamente 33 transexuais (masculinos e femininos). Outros objetivos foram comparar Depressão e Transtornos de Personalidade após dois anos de psicoterapia grupal e estruturar um temário específico para ela. Foram aplicados: SCID-I/P, Beck, Hamilton e Entrevista Estruturada para Distúrbios da Personalidade pelo DSM-III-R. As características demográficas gerais não variaram nos grupos. Não houve nenhum diagnóstico psiquiátrico prevalente. Houve predomínio de sintomas depressivos e não de quadros clínicos de depressão. Quanto aos transtornos e traços de personalidade, nenhum dado estatisticamente significativo foi encontrado. Temas para psicoterapia foram estabelecidos. / This study aimed to evaluate the presence of personality disorders of axis I as well as to characterize demographically 33 transsexuals (male and female). Other objectives were to compare depression and personality disorders after two years of group therapy and structure a specific theme list to it. SCID-I/P, Beck, Hamilton and Structured Interview for Personality disorders by the DMS-III-R were applied. General demographic characteristics did not vary among the groups. There was no prevailing psychiatric diagnosis. As for disorders and personality traits, no statistically significant data was found. Psychotherapy themes were established.

Esse estudo propôs-se avaliar presença de transtornos de eixo I, personalidade e caracterizar demograficamente 33 transexuais (masculinos e femininos). Outros objetivos foram comparar Depressão e Transtornos de Personalidade após dois anos de psicoterapia grupal e estruturar um temário específico para ela. Foram aplicados: SCID-I/P, Beck, Hamilton e Entrevista Estruturada para Distúrbios da Personalidade pelo DSM-III-R. As características demográficas gerais não variaram nos grupos. Não houve nenhum diagnóstico psiquiátrico prevalente. Houve predomínio de sintomas depressivos e não de quadros clínicos de depressão. Quanto aos transtornos e traços de personalidade, nenhum dado estatisticamente significativo foi encontrado. Temas para psicoterapia foram estabelecidos. / This study aimed to evaluate the presence of personality disorders of axis I as well as to characterize demographically 33 transsexuals (male and female). Other objectives were to compare depression and personality disorders after two years of group therapy and structure a specific theme list to it. SCID-I/P, Beck, Hamilton and Structured Interview for Personality disorders by the DMS-III-R were applied. General demographic characteristics did not vary among the groups. There was no prevailing psychiatric diagnosis. As for disorders and personality traits, no statistically significant data was found. Psychotherapy themes were established.