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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.
21

Estudo da análise preços de negociação de empresas comparativamente à avaliação de empresas por opções reais: estudo de caso de empresas do setor de telecomunicações / Study of the analysis prices of negotiation of companies comparativily to the valuation of companies for real options: study of case with companies in telecommunications sector

Kuronuma, Alexandre Maurício 27 March 2006 (has links)
Made available in DSpace on 2016-04-25T16:44:44Z (GMT). No. of bitstreams: 1 Dissertacao Alexandre Kuronuma 27_01_06.pdf: 443263 bytes, checksum: 92e0f41a6d016f127624da3eb45dd052 (MD5) Previous issue date: 2006-03-27 / nenhum / The purpose of this report is to analyze the use of the real option theory in the valuation of companies compared to the actual values of deals in the telecommunications sector in Brazil. This study focused on the case of two mobile phone companies formed by the sale of the license concessions of the B band in 1997: BCP Telecomunicações and BSE Telecomunicações. These companies had been evaluated using eighteen different scenarios created by the combination of three variables (volatility, free tax of risk and the cost of the debt), using the call option model of Black and Scholes. The results shown that although both companies present negative values for its real equity in December, 31 - 2002, the companies had presented a positive value for the real option model, showing the effectiveness of this methodology in companies valuation. As a result of our analysis, we concluded that the use of real options valuation is a viable alternative if compared with the traditional valuation methodologies / O objetivo deste trabalho é analisar a utilização da teoria das opções reais na avaliação de empresas comparativamente a valores de negociação em empresas do setor de telecomunicações. As empresas avaliadas por esse modelo foram companhias formadas a partir da venda das licenças de concessão de telefonia móvel banda B e que foram adquiridas integralmente após a sua formação. O desenvolvimento foi através de um estudo de caso com duas empresas de telefonia móvel, formadas a partir da venda da concessão das licenças de banda B em 1997, a BCP Telecomunicações e a BSE Telecomunicações. Essas empresas foram avaliadas, dentro de dezoito cenários, definidos a partir de três variáveis (volatilidade, taxa livre de risco e custo da dívida), através do modelo de precificação de opções de compra de Black e Scholes. Os resultados mostraram que, apesar de as empresas apresentarem valores negativos para o seu patrimônio líquido real em 31 de dezembro de 2002, ambas revelaram um valor positivo pelo modelo de precificação por opções reais, o que mostra a eficácia no uso dessa metodologia na avaliação de empresas. Como resultado deste trabalho, através dos números encontrados e analisados, conclui-se que o uso da avaliação por opções reais é uma alternativa viável se comparada às metodologias tradicionais de avaliação
22

Multi-agent Consensus Using Generalized Cyclic Pursuit Strategies

Sinha, Arpita 07 1900 (has links)
One of the main focus of research on multi-agent systems is that of coordination in a group of agents to solve problems that are beyond the capability of a single agent. Each agent in the multi-agent system has limited capacity and/or knowledge which makes coordination a challenging task. Applications of multi-agent systems in space and ocean exploration, military surveillance and rescue missions, require the agents to achieve some consensus in their motion. The consensus has to be achieved and maintained without a centralized controller. Multi-agent system research borrows ideas from the biological world where such motion consensus strategies can be found in the flocking of birds, schooling of fishes, and colony of ants. One such classes of strategies are the cyclic pursuit strategies which mimic the behavior of dogs, birds, ants, or beetles, where one agent pursues another in a cyclic manner, and are commonly referred to as the `bugs' problem, In the literature, cyclic pursuit laws have been applied to a swarm of homogenous agents, where there exists a predefined cyclic connection between agents and each agent follows its predecessor. At equilibrium, the agents reach consensus in relative positions. Equilibrium formation, convergence, rate of convergence, and stability are some of the aspects that have been studied under cyclic pursuit. In this thesis, the notion of cyclic pursuit has been generalized. In cyclic pursuit, usually agents are homogenous in the sense of having identical speeds and controller gains where an agent has an unique predecessor whom it follows. This is defined as the basic cyclic pursuit (BCP) and the sequence of connection among the agents is defined as the Pursuit sequence (PS). We first generalize this system by assuming heterogeneous speed and controller gains. Then, we consider a strategy where an agent can follow a weighted centroid of a group of other agents instead of a single agent. This is called centroidal cyclic pursuit (CCP). In CCP, the set of weights used by the agents are assumed to be the same. We generalize this further by considering the set of weights adopted by each agent to be different. This defines a generalized centroidal cyclic pursuit (GCCP). The behavior of the agents under BCP, CCP and GCCP are studied in this thesis. We show that a group of holonomic agents, under the cyclic pursuit laws ¡ BCP, CCP and GCCP ¡ can be represented as a linear system. The stability of this system is shown to depend on the gains of the agents. A stable system leads to a rendezvous of the agents. The point of rendezvous, also called the reachable point, is a function of the gains. In this thesis, the conditions for stability of the heterogeneous system of agents in cyclic pursuit are obtained. Also, the reachable point is obtained as a function of the controller gains. The reachable set, which is a region in space where rendezvous can occur, given the initial positions of the agents, are determined and a procedure is proposed for calculating the gains of the agents for rendezvous to occur at any desired point within the reachable set. Invariance properties of stability, reachable point and reachable set, with respect to the pursuit sequence and the weights are shown to exist for these linear cyclic pursuit laws. When the linear system is unstable, the agents are shown to exhibit directed motion. We obtain the conditions under which such directed motion is possible. The straight line asymptote to which the agents converge is characterized by the gains and the pursuit sequence of the agents. The straight lines asymptote always passes through a point, called the asymptote point, for given initial positions and gains of the agents. This invariance property of the asymptote point with respect to the pursuit sequence and the weights are proved. For non-homonymic agents, cyclic pursuit strategies give rise to a system of nonlinear state equations. It is shown that the system at equilibrium converges to a rigid polygonal formation that rotates in space. The agents move in concentric circles at equilibrium. The formation at equilibrium and the conditions for equilibrium are obtained for heterogeneous speeds and controller gains. The application of cyclic pursuit strategies to autonomous vehicles requires the satisfaction of some realistic restrictions like maximum speed limits, maximum latex limits, etc. The performances of the strategies with these limitations are discussed. It is also observed that the cyclic pursuit strategies can also be used to model some behavior of biological organisms such as schools of fishes.
23

Simula??o computacional da intera??o fluido-estrutura em bombas de cavidades progressivas

Almeida, Rairam Francelino Cunha de 26 March 2010 (has links)
Made available in DSpace on 2014-12-17T14:58:00Z (GMT). No. of bitstreams: 1 RairamFCA_DISSERT2.pdf: 4758176 bytes, checksum: bfb1653549a50848b4721bda9a78bd6e (MD5) Previous issue date: 2010-03-26 / The pumping through progressing cavities system has been more and more employed in the petroleum industry. This occurs because of its capacity of elevation of highly viscous oils or fluids with great concentration of sand or other solid particles. A Progressing Cavity Pump (PCP) consists, basically, of a rotor - a metallic device similar to an eccentric screw, and a stator - a steel tube internally covered by a double helix, which may be rigid or deformable/elastomeric. In general, it is submitted to a combination of well pressure with the pressure generated by the pumping process itself. In elastomeric PCPs, this combined effort compresses the stator and generates, or enlarges, the clearance existing between the rotor and the stator, thus reducing the closing effect between their cavities. Such opening of the sealing region produces what is known as fluid slip or slippage, reducing the efficiency of the PCP pumping system. Therefore, this research aims to develop a transient three-dimensional computational model that, based on single-lobe PCP kinematics, is able to simulate the fluid-structure interaction that occurs in the interior of metallic and elastomeric PCPs. The main goal is to evaluate the dynamic characteristics of PCP s efficiency based on detailed and instantaneous information of velocity, pressure and deformation fields in their interior. To reach these goals (development and use of the model), it was also necessary the development of a methodology for generation of dynamic, mobile and deformable, computational meshes representing fluid and structural regions of a PCP. This additional intermediary step has been characterized as the biggest challenge for the elaboration and running of the computational model due to the complex kinematic and critical geometry of this type of pump (different helix angles between rotor and stator as well as large length scale aspect ratios). The processes of dynamic generation of meshes and of simultaneous evaluation of the deformations suffered by the elastomer are fulfilled through subroutines written in Fortan 90 language that dynamically interact with the CFX/ANSYS fluid dynamic software. Since a structural elastic linear model is employed to evaluate elastomer deformations, it is not necessary to use any CAE package for structural analysis. However, an initial proposal for dynamic simulation using hyperelastic models through ANSYS software is also presented in this research. Validation of the results produced with the present methodology (mesh generation, flow simulation in metallic PCPs and simulation of fluid-structure interaction in elastomeric PCPs) is obtained through comparison with experimental results reported by the literature. It is expected that the development and application of such a computational model may provide better details of the dynamics of the flow within metallic and elastomeric PCPs, so that better control systems may be implemented in the artificial elevation area by PCP / O sistema de bombeamento por cavidades progressivas est? sendo cada vez mais empregado na ind?stria do petr?leo, devido ? sua capacidade de eleva??o de ?leos altamente viscosos ou de fluidos com grandes concentra??es de areia ou outras part?culas s?lidas. Uma Bomba de Cavidades Progressivas (BCP) ? composta, basicamente, por um rotor - uma pe?a met?lica de forma semelhante a um parafuso exc?ntrico, e um estator - um tubo de a?o revestido internamente por uma h?lice dupla, a qual pode ser r?gida ou deform?vel/elastom?rica. Em geral, uma BCP ? submetida a uma combina??o de press?o do po?o com press?o gerada pelo pr?prio processo de bombeio. Em BCPs elastom?ricas, essa combina??o de esfor?os comprime o estator, gerando ou aumentando a folga existente entre o rotor e o estator, reduzindo, portanto, o efeito de veda??o entre suas cavidades. Tal abertura da regi?o de selagem produz o que ? conhecido como escorregamento do fluido, diminuindo, com isso, a efici?ncia de sistema de bombeio por BCP. Dessa maneira, este trabalho se prop?e a desenvolver um modelo computacional tridimensional transiente do processo din?mico da intera??o fluido-estrutural (FSI) que ocorre no interior de BCPs met?licas e elastom?ricas. O objetivo principal ? avaliar, a partir do uso do modelo desenvolvido, as caracter?sticas din?micas de efici?ncia de bombeio por BCPs, em fun??o de informa??es locais e instant?neas detalhadas dos campos de velocidade, press?o e deforma??o no seu interior. Para o alcance de tais metas (desenvolvimento e uso do modelo), fez-se necess?rio o desenvolvimento de uma metodologia pr?pria para gera??o de malhas computacionais din?micas, m?veis e deform?veis, representando as regi?es fluida e estrutural de uma BCP. Tal procedimento caracterizou-se como o maior desafio para a elabora??o do modelo computacional, devido ? cinem?tica complexa e ? geometria cr?tica desse tipo de bomba (?ngulos de h?lice diferentes entre rotor e estator e grandes diferen?as de escala de comprimento). Os processos de gera??o din?mica das malhas e de avalia??o simult?nea das deforma??es sofridas pelo elast?mero s?o realizados atrav?s de sub-rotinas em linguagem Fortran 90, as quais interagem dinamicamente com o software de din?mica dos fluidos computacional CFX/ANSYS. Desde que o modelo linear el?stico ? empregado para avaliar as deforma??es elastom?ricas, n?o ? necess?rio usar nenhum software para an?lise estrutural. Entretanto, uma proposta inicial para simula??o din?mica no ANSYS empregando-se modelos constitutivos hiper-el?sticos para o elast?mero ? tamb?m apresentada no presente trabalho. A valida??o dos resultados produzidos com a presente metodologia (gera??o de malha, simula??o do escoamento em BCPs met?licas e simula??o da intera??o fluido-estrutural em BCPs elastom?ricas) ? obtida atrav?s da compara??o com resultados experimentais reportados pela literatura. Vislumbra-se que o desenvolvimento e aplica??o de tal ferramenta computacional poder?o fornecer maiores detalhes da din?mica do escoamento no interior de BCPs met?licas e elastom?ricas, de maneira que melhores sistemas de controle possam ser implementados na ?rea de eleva??o artificial por BCPs
24

Gestão de continuidade de negócios aplicada no ensino presencial mediado por recursos tecnológicos. / Business continuity management (BCM) used to they education system mediated classroom resources technology (SPMRT).

Gorayeb, Diana Maria da Câmara 13 February 2012 (has links)
Este trabalho propõe diretrizes de Gestão de Continuidade de Negócios (GCN) para a tecnologia de Ensino Presencial Mediado por Recursos Tecnológicos (EPMRT), que conta, para a realização de suas atividades acadêmicas, com um sistema complexo para transmissão de aulas e exige um grande esforço para o controle das suas operações e das respostas coordenadas diante de erros, falhas e defeitos, ou quaisquer incidentes que resultem na interrupção das suas atividades. A manutenção deste ambiente tecnológico está relacionada com a implantação de processos eficientes de gestão de risco e do ciclo de melhoria contínua em ambiente de TI com a adoção do ITIL® e através da construção das diretrizes de um Plano de Continuidade de Negócios (PCN), documentado por meio de elementos da UML, utilizando a Análise de Impacto nos Negócios (BIA), a Avaliação dos Riscos (RA) e os atributos de Dependabilidade para os elementos tecnológicos: disponibilidade, confiabilidade, segurança, confidencialidade, integridade e manutenibilidade. / This paper proposes guidelines for Business Continuity Management (BCM) that uses a technology called Education System Mediated Classroom Resources Technology (SPMRT), which needs, for the achievement of their academic activities, a complex system for transmission of lessons and requires a great effort to control their operations and coordinated fast responses in case of errors, faults, attacks and defects, or any incidents that result in the disruption of their activities. Maintaining this technological environment is related to the implementation of efficient processes of risk management and continuous improvement cycle in the IT environment with the adoption of ITIL® and through the construction of a Business Continuity Plan (BCP), documented by elements of the UML using the Business Impact Analysis (BIA), Risk Assessment (RA) and the attributes of Dependability: availability, reliability, security, confidentiality, integrity and maintainability.
25

Gestão de continuidade de negócios aplicada no ensino presencial mediado por recursos tecnológicos. / Business continuity management (BCM) used to they education system mediated classroom resources technology (SPMRT).

Diana Maria da Câmara Gorayeb 13 February 2012 (has links)
Este trabalho propõe diretrizes de Gestão de Continuidade de Negócios (GCN) para a tecnologia de Ensino Presencial Mediado por Recursos Tecnológicos (EPMRT), que conta, para a realização de suas atividades acadêmicas, com um sistema complexo para transmissão de aulas e exige um grande esforço para o controle das suas operações e das respostas coordenadas diante de erros, falhas e defeitos, ou quaisquer incidentes que resultem na interrupção das suas atividades. A manutenção deste ambiente tecnológico está relacionada com a implantação de processos eficientes de gestão de risco e do ciclo de melhoria contínua em ambiente de TI com a adoção do ITIL® e através da construção das diretrizes de um Plano de Continuidade de Negócios (PCN), documentado por meio de elementos da UML, utilizando a Análise de Impacto nos Negócios (BIA), a Avaliação dos Riscos (RA) e os atributos de Dependabilidade para os elementos tecnológicos: disponibilidade, confiabilidade, segurança, confidencialidade, integridade e manutenibilidade. / This paper proposes guidelines for Business Continuity Management (BCM) that uses a technology called Education System Mediated Classroom Resources Technology (SPMRT), which needs, for the achievement of their academic activities, a complex system for transmission of lessons and requires a great effort to control their operations and coordinated fast responses in case of errors, faults, attacks and defects, or any incidents that result in the disruption of their activities. Maintaining this technological environment is related to the implementation of efficient processes of risk management and continuous improvement cycle in the IT environment with the adoption of ITIL® and through the construction of a Business Continuity Plan (BCP), documented by elements of the UML using the Business Impact Analysis (BIA), Risk Assessment (RA) and the attributes of Dependability: availability, reliability, security, confidentiality, integrity and maintainability.

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