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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.
131

Método para estimar custos diretos da execução de edifícios: aplicação à alvenaria estrutural. / Method to forecast direct costs for multi-storey building construction: tested for structural mansonry.

Kato, Camila Seiço 09 November 2012 (has links)
O trabalho de mestrado propõe um método para estimar custos diretos de edificações, através da análise de fatores que comparam o edifício a ter o custo prognosticado com outro tomado como referência. Esta ferramenta é muito útil na medida em que a análise de custos durante estágios iniciais do empreendimento auxilia as empresas de Construção Civil a tomar decisões importantes, tais como a compra do terreno, o lançamento do empreendimento, a escolha da concepção arquitetônica da edificação, entre outras. O método utilizado para a elaboração desta ferramenta foi a modelagem, pois utilizou-se de análises paramétricas para descrever o funcionamento do prognóstico de custos. A simulação da ferramenta desenvolvida foi feita para o serviço de alvenaria estrutural, e envolveu levantamento bibliográfico para conhecer e quantificar os aspectos técnicos e arquitetônicos que influenciam o custo deste serviço. O método proposto, apesar de ter um desenvolvimento complexo, possui vantagens em relação a outros estudados na revisão bibliográfica, tais como: precisão, rapidez na utilização em alvenaria estrutural, entendimento de fatores influenciadores, possibilidade de atualização do método, utilização por diferentes empresas, comparação de diferentes projetos arquitetônicos. / This thesis proposes a method to forecast direct costs for multi-storey building construction. The costs are estimated by comparison to another building which costs were estimated before. The cost estimation this method provides can be very useful to improve important decisions including: land purchasing, timing to initiate marketing campaigns, and selecting architectural concepts. The approach to develop this method was modelling; parametrical analyses were used to describe the cost prognosis. The conceptual model was tested for structural masonry direct cost estimate. To do so, bibliographical survey was used in order to identify and quantify the impact of technical and architectonic parameters on the cost of this service. The proposed method, although complex, presents many advantages when compared to existing methods including: its accuracy, speed when used for structural masonry estimates, the understanding of the trigger parameters, it is easy to include new information, allows diversity of users, and its ability to compare different architectural designs.
132

Ecologia da pesca artesanal no médio rio Tocantins, Imperatriz (MA) / Ecology of the artisanal fishing in the medium river Tocantins, Imperatriz (MA)

Cetra, Mauricio 05 June 1998 (has links)
Neste trabalho é analisado um levantamento realizado em 1988 para se quantificar a produção pesqueira na região do médio rio Tocantins, a fim de avaliar a importância da atividade pesqueira para as populações locais. Visa compreender a forma de adaptação das técnicas utilizadas pelos pescadores às características ecológicas das espécies alvo das pescarias, considerando as mudanças ambientais ocorridas durante um ciclo hidrológico. Os peixes adaptaram suas estratégias de vida às variações sazonais, assim como, a comunidade de pescadores se adaptou a esta variabilidade espaço-temporal escolhendo estratégias de captura apropriadas. Os pescadores conseguiram uma seleção das espécies a partir de um conhecimento aprofundado do ambiente, dos organismos que nele habitam e da seletividade dos apetrechos aplicados. Os pescadores ficam obrigados a fornecer toda a sua produção aos primeiros atravessadores em troca do financiamento de gastos na manutenção dos barcos, compra de combustível, manutenção dos apetrechos, e fornecimento de gelo para conservação do pescado. Existe uma preferência em se capturar peixes de escama, como a curimatá Prochilodus nigricans e o jaraqui Semaprochilodus brama, apesar de terem um valor comercial inferior. Esta preferência é determinada pela grande abundância e aceitação no mercado local. Dados recentes de levantamento dos recursos pesqueiros feito pelo Ministério do Meio Ambiente na mesma região, forneceram informações importantes, as quais permitem concluir que alterações nas características físicas e biológicas do médio rio Tocantins, provocadas pela construção da barragem de Tucuruí, propiciaram ao mampará Hipophtalmus marginatus a conquista dos ambientes situados acima desta área. Durante a época de defeso, os Siluriformes passam a ser o alvo das pescarias, o que irá afetar negativamente a estrutura da comunidade de peixes do médio rio Tocantins. Através dos dados de captura por arrastão de praia em 1988, utilizando o número de lances como unidade de esforço, estimou-se a população de curimatá, existente no trecho que vai de Imperatriz (MA) até a zona de confluência entre os rios Araguaia e Tocantins, utilizando-se o método de depleção. Estimou-se uma população em torno de 200 t, com um intervalo variando de 174 t a 227 t / In this thesis, a survey carried out in 1988 is analysed in order to quantify the fishing production in the area of the medium river Tocantins, and to evaluate the importance of the fishing activity for the local populations. It is aimed to understand the adaptation of the techniques used by the fishermen to the ecological characteristics of the fisheries target species, considering the environmental changes during a hidrological cycle. The fishes adapted its life strategies to the seasonal variations, as well as, the community of fishermen adapted themselves to this space-temporal variability choosing apropriate capture strategies. The fishermen select the species based in their knowledgement of the environment, and of its organisms through the selectivity of the fishing gears. Fishermen are forced to supply all its production to the first merchant in exchange of financing the expenses in order to maintain the ships, buying fuel, uphold the equipments, and supply ice for fish conservation. A preference exists in capturing scale fish, as the curimatá Prochilodus nigricans and the jaraqui Semaprochilodus brama, in spite of having inferior commercial value. This preference is determined by their abundance and acceptance in the local market. Recent surveys performed by the Ministry of the Environment in the same area, supplied important information, which allow to conclude that alterations in the physical and biological characteristics of the medium river Tocantins, provoked by the construction of the dam of Tucuruí, allowed the mampará Hipophtalmus marginatus the conquest of the environments above this area. During the closed season, Siluriformes becomes the target of the fisheries, which afect will negatively the structure of the fish community. The curimatá population, extending from Imperatriz (MA) till the confluence zone of the rivers Araguaia and Tocantins has been estimated for 1988, using the depletion method, as 200 t, with an interval varying from 174 t to 227 t
133

Atratores para equações da onda amortecida em domínios arbitrários / Attractors for damped wave equations on an arbitrary domain

Nogueira, Ariadne 26 March 2013 (has links)
Nesse trabalho apresentamos o estudo do artigo [25] que analisa a existência de atratores globais para uma classe de equações da onda amortecida da forma \'épsilon u IND. tt\' + \'alpha\' (x) u IND. t\' + \'BETA\' (x)u - \'\\SIGMA SOBRE i, j\' \'\\PARTIAL ind. I\' (\'a IND. i j\' (x) \'PARTIAL IND. j u\') = f(x, u) , x PERTENCE A ÔMEGA\'\', t \'PERTENCE A\' [0,\'infinito\'), u (x, t) = 0, x \'PERTENCE A\' \'\\PARTIAL ÔMEGA\', t \'PERTENCE A\' [0, \'infinito\') definidas em um domínio arbitrário \'ÔMEGA\' / In this work we describe the results of the paper [25]. In [25] the authors prove existence of global attractors for the following semilinear damped wave equation \'\\épsilon u IND. t\'t + \'alpha\'(x)u IND. t\' + \'beta\' (x)u - \'\\SIGMA SOBRE i, j \'\\PARTIAL IND. i\' (\'a IND. i j\' (x) \'\\PARTIAL IND. j u\') = f (x, u), x \'IT BELONGS\' \'ÔMEGA\', t \'IT BELONGS\' [0, \'INFINITY\'), u(x,t), x \'IT BELONGS\' \'\\PARTIAL ÔMEGA\', t \'IT BELONGS\' [), \'INFINITY\'0 on an arbitrary domain \'OMEGA\'
134

Desenvolvimento de um método para elaboração de redes de composições de custo para orçamentação de obras de edificações. / Developing a method to prepare unit cost item nets for buildings estimating.

Marchiori, Fernanda Fernandes 30 October 2009 (has links)
Nesta tese é apresentado o desenvolvimento de um método para elaboração de composições de custo voltado a obras de edificações. Esta abordagem, que considera as composições orçamentárias em forma de redes, foi elaborada a fim de criar uma lógica para a estruturação da massa de informações envolvidas no processo de orçar. Inicialmente foi feita uma revisão bibliográfica e um estudo exploratório que apontaram para tal necessidade. Tendo-se por base trabalhos anteriores de levantamento de produtividade em obra, propôs-se um método para elaboração de composições. Este método foi aplicado levando-se em conta o contexto das obras de um agente da cadeia produtiva da Construção Civil: um órgão financiador de obras (a Caixa Econômica Federal). Tal uso serviu para mostrar a aplicabilidade do método desenvolvido com base bibliográfica, mas também acabou sendo útil para alguns aprimoramentos do mesmo, fazendo uso das discussões entre pesquisadores e pesquisados, chegando-se, então, ao método final apresentado nesta tese. Desta forma, o método de desenvolvimento das redes de composições proposto fornece subsídios para alocação e tratamento das informações sobre custos de obra, resolvendo parte das críticas apontadas pela literatura, propiciando composições mais precisas frente às novas disponibilidades de dados e dando um suporte consistente e adequado às necessidades do gerenciamento dos custos de produção de edificações. / This thesis develops a method that helps experts arrive at unit price items for buildings. It is based on the consideration of a unit price item net as the logical way to deal with the huge amount of information associated to the estimating process. The preliminary bibliography review and an exploratory study showed the accuracy of the authors initial concerns. The method developed was based upon former productivity studies and was applied in the production of unit price items net for Caixa Econômica Federal, a public building construction financial company. Such experience showed not only that the method was feasible but also pointed out some improvements that should be made, leading to the method presented in the thesis. Finally, it can be said the method used to develop unit price item nets can help allocate and deal with information about construction costs; it solved several problems indicated by literature, improving compositions in terms of precision, and of support to cost management in the building construction area.
135

Clinical and epidemiological issues and applications of mammographic density

Assi, Valentina January 2014 (has links)
Mammographic density, the amount of radiodense tissue on a mammogram, is a strong risk factor for breast cancer, with properties that could be an asset in screening and prevention programmes. Its use in risk prediction contexts is currently limited, however, mainly due to di culties in measuring and interpreting density. This research investigates rstly, the properties of density as an independent marker of breast cancer risk and secondly, how density should be measured. The rst question was addressed by analysing data from a chemoprevention trial, a trial of hormonal treatment, and a cohort study of women with a family history of breast cancer . Tamoxifen-induced density reduction was observed to be a good predictor of breast cancer risk reduction in high-risk una ected subjects. Density and its changes did not predict risk or treatment outcome in subjects with a primary invasive breast tumour. Finally absolute density predicted risk better than percent density and showed a potential to improve existing risk-prediction models, even in a population at enhanced familial risk of breast cancer. The second part of thesis focuses on density measurement and in particular evaluates two fully-automated volumetric methods, Quantra and Volpara. These two methods are highly correlated and in both cases absolute density (cm3) discriminated cases from controls better than percent density. Finally, we evaluated and compared di erent measurement methods. Our ndings suggested good reliability of the Cumulus and visual assessments. Quantra volumetric estimates appeared negligibly a ected by measurement error, but were less variable than visual bi-dimensional ones, a ecting their ability to discriminate cases from controls. Overall, visual assessments showed the strongest association with breast cancer risk in comparison to computerised methods. Our research supports the hypothesis that density should have a role in personalising screening programs and risk management. Volumetric density measuring methods, though promising, could be improved.
136

A new adaptive multiscale finite element method with applications to high contrast interface problems

Millward, Raymond January 2011 (has links)
In this thesis we show that the finite element error for the high contrast elliptic interface problem is independent of the contrast in the material coefficient under certain assumptions. The error estimate is proved using a particularly technical proof with construction of a specific function from the finite dimensional space of piecewise linear functions. We review the multiscale finite element method of Chu, Graham and Hou to give clearer insight. We present some generalisations to extend their work on a priori contrast independent local boundary conditions, which are then used to find multiscale basis functions by solving a set of local problems. We make use of their regularity result to prove a new relative error estimate for both the standard finte element method and the multiscale finite element method that is completely coefficient independent. The analytical results we explore in this thesis require a complicated construction. To avoid this we present an adaptive multiscale finite element method as an enhancement to the adaptive local-global method of Durlofsky, Efendiev and Ginting. We show numerically that this adaptive method converges optimally as if the coefficient were smooth even in the presence of singularities as well as in the case of a realisation of a random field. The novel application of this thesis is where the adaptive multiscale finite element method has been applied to the linear elasticity problem arising from the structural optimisation process in mechanical engineering. We show that a much smoother sensitivity profile is achieved along the edges of a structure with the adaptive method and no additional heuristic smoothing techniques are needed. We finally show that the new adaptive method can be efficiently implemented in parallel and the processing time scales well as the number of processors increases. The biggest advantage of the multiscale method is that the basis functions can be repeatedly used for additional problems with the same high contrast material coefficient.
137

Review of Current Estimating Capabilities of the 3d Building Information Model Software to Support Design for Production/Construction

Farah, Toni E 23 August 2005 (has links)
"The fragmented environment in the construction industry has a big influence on production. The multi-disciplinary nature of the project development process imposes the need for clear communications and team effort coordination. Information Technology (IT) has been playing a tremendous role in facilitating this process. The most recent contribution of IT in this regard is the Building Information Model (BIM). It is clear that BIM technology improves the design drawings productivity; drawings are automatically coordinated in all views from plans, to sections, to elevations, to details and to perspectives. It also provides an innovative way of scheduling through by allowing a 3D visualization of the construction progress. But, there are still many technical issues that still need to be addressed before this technology is fully adopted by the industry. For example, what are the files formats that BIM supports? What is the needed knowledge for best use of BIM? How does BIM integrate with the estimating discipline? Where does BIM store the building data? What are the codes that are shown in the automatically generated “quantity take-offs” schedules? This research attempts to provide answers to these questions and explores possible ways to link different coding systems within the BIM platform itself. After reviewing the basic design concepts from the conceptual to the construction stages and how it is related to the different project delivery ways, this work illustrates the role of different work breakdown structures (WBS) in the life cycle of estimating discipline from the preliminary to the detailed stage. The research reviewed the different database designs and structures, the database management systems (DBMS), as well as the database organization systems. This review draws a picture on how information system (IS) and its tools support the different needs of the multiple players involved in a construction project. The focus was on the object oriented database and building information model (BIM) software, and how it integrates with other estimating and project planning software. The findings seem promising, but before BIM technology can reshape the construction industry, it is still necessary to conduct additional experimental work as the software continues to evolve and becomes mature."
138

Well-posedness and scattering of the Chern-Simons-Schrödinger system

Lim, Zhuo Min January 2017 (has links)
The subject of the present thesis is the Chern-Simons-Schrödinger system, which is a gauge-covariant Schrödinger system in two spatial dimensions with a long-range electromagnetic field. The present thesis studies two aspects of the system: that of well-posedness and that of the long-time behaviour. The first main result of the thesis concerns the large-data well-posedness of the initial-value problem for the Chern-Simons-Schrödinger system. We impose the Coulomb gauge to remove the gauge-invariance, in order to obtain a well-defined initial-value problem. We prove that, in the Coulomb gauge, the Chern-Simons-Schrödinger system is locally well-posed in the Sobolev spaces $H^s$ for $s\ge 1$, and that the solution map satisfies a weak Lipschitz continuity estimate. The main technical difficulty is the presence of a derivative nonlinearity, which rules out the naive iteration scheme for proving well-posedness. The key idea is to retain the non-perturbative part of the derivative nonlinearity in the principal operator, and to exploit the dispersive properties of the resulting paradifferential-type principal operator, in particular frequency-localised Strichartz estimates, using adaptations of the $U^p$ and $V^p$ spaces introduced by Koch and Tataru in other contexts. The other main result of the thesis characterises the large-time behaviour in the case where the interaction potential is the defocusing cubic term. We prove that the solution to the Chern-Simons-Schrödinger system in the Coulomb gauge, starting from a localised finite-energy initial datum, will scatter to a free Schrödinger wave at large times. The two crucial ingredients here are the discovery of a new conserved quantity, that of a pseudo-conformal energy, and the cubic null structure discovered by Oh and Pusateri, which reveals a subtle cancellation in the long-range electromagnetic effects. By exploiting pseudo-conformal symmetry, we also prove the existence of wave operators for the Chern-Simons-Schrödinger system in the Coulomb gauge: given a localised finite-energy final state, there exists a unique solution which scatters to that prescribed state.
139

Otimização da técnica de captura-recaptura fotográfica para estimação da população canina livre em vias públicas / Optimization of photographic capture-recapture technique for estimation of free canine population in public roads

Shimozako, Helio Junji 05 September 2008 (has links)
Embora os cães sejam um dos animais de convívio mais estreito e harmonioso com o ser humano, quando esta referida população se encontra fora do controle, ela pode gerar agravos, tanto com relação à saúde humana e de outros animais quanto ao meio ambiente. Assim, estudos relacionados à estimativa de seu tamanho populacional e aos métodos de controle são importantes para o desenvolvimento de estratégias cada vez mais eficazes. Este estudo teve como objetivos principais avaliar a técnica de fotoidentificação para a espécie canina e apresentar uma proposta para aprimorar o método de captura-recaptura fotográfica. Para tanto, foram obtidas fotografias de cães a partir de duas fontes distintas, sendo uma a partir de cães internados no canil de adoção do Centro de Controle de Zoonoses (CCZ) grupo controle, padrão ouro e a outra de cães soltos nas ruas de Ibiúna/SP. Os cães do CCZ foram fotografados seguindo 4 tipos diferentes de protocolo, o que gerou 4 diferentes padrões de catálogos fotográficos. Esses 4 catálogos se diferenciaram entre si em termos de visualização do cão e de número de fotografias necessárias para apresentar cada animal (dependendo do catálogo, este poderia ser representado por uma a quatro fotografias). Em um segundo momento, foi realizado uma busca de cães livres nas ruas do bairro de Santa Lúcia (Ibiúna/SP) por três dias. Cada animal encontrado foi fotografado e estas foram classificadas conforme o padrão dos catálogos determinados para as fotografias dos cães do CCZ. Por fim, 103 voluntários observaram pares de conjunto de fotografias dos cães (tanto as do CCZ quanto as do bairro) por meio da Internet e apontaram quais deles correspondiam aos mesmos cães, na opinião deles. Além disso, seguindo o método clássico de captura-recaptura, foi estimado a população de cães nas ruas do bairro sob a ótica do pesquisador (isto é, de uma única pessoa). Entre os principais resultados, tomando as fotos obtidas do CCZ como padrão ouro, as probabilidades de se identificar e de se distinguir corretamente os cães por meio da fotografia (para o voluntário) foi de 95,0% e 99,8%, respectivamente, e o índice Kappa calculado para a concordância entre os resultados dos voluntários e do padrão ouro foi de 0,963. Com base no uso das probabilidades calculadas do padrão ouro, a estimativa da população canina livre passou por um ajuste e foi estimada em torno de 65 animais (I.C. 95% 64 a 67 animais). A estimativa das probabilidades de identificação foi interessante no sentido de ajustar o N calculado, tornando esta estimativa mais precisa / The dog is one of the most popular pet in the world. However, if this population is out of control, injuries against human beings, other animals and environment can occur. Therefore, studies related to dog population are important in order to optimize methods and strategies of control. The main objectives of this research are evaluating the photo-identification technique for dogs and presenting a suggestion to improve the photographic capturerecapture method. For this, pictures of dogs were acquired from two different sources. One of them was the Zoonosis Control Center (ZCC) gold standard and the other one were the free dogs from Ibiúna City streets. The dogs from ZCC were photographed following four protocols. Therefore, I obtained four photographic catalogs. The difference between these catalogs was the visualization of dog´s physical characterestics and the necessary number of pictures (one to four) to present each animal. Second, a survey of free dogs in the Ibiúna City had been carried out during three days. Each dog found in the streets was photographed and, after that, the pictures were classified according to the model of catalogs acquired from ZCC dogs pictures. Finally, 103 volunteers observed set of pairs of pictures (both ZCC and streets) by means of Internet and pointed which of them were from the same dogs. In addition, the dog population was estimated by following the classical capture-recapture method. Considering the results from the ZCC pictures observation, the correctly identifying and distinguishing dogs probabilities by means of pictures (for the volunteer) was 95,0% and 99,8%, respectively. In this case, the kappa value between these volunteers results and the gold standard was 0,963. Using the calculated probabilities from the gold standard, the estimated population (N) was adjusted to about 65 animals (C.I. 95% 64 to 67 animals). The estimation of the probabilities from the gold standard was interesting for adjusting the calculated (N) and improving the precision
140

Custos de infra-estrutura: parâmetros de uma cidade média do interior do Estado de São Paulo. / Parameters of a city in the state of Sao Paulo, Brazil.

Eloy, Evandro José da Silva 01 June 2010 (has links)
Este trabalho apresenta parâmetros de custos para implantação de redes de infra-estrutura urbana (drenagem, pavimentação, água, esgoto, energia elétrica e arborização) em parcelamentos de solo realizados em uma cidade média do interior do estado de São Paulo. Realiza-se a análise dos sistemas de infra-estrutura, dos métodos para estimativas de custos e do processo para aprovação de projetos, decompondo e caracterizando as diversas partes constituintes. Através dos estudos de caso são apresentados os custos dos diferentes subsistemas e a incidência desses no sistema de infra-estrutura urbana como um todo. Espera-se contribuir para o entendimento dos fatores que condicionam os custos dos sistemas utilizados em cidades médias. / This paper presents cost parameters for deployment of networks of urban infrastructure (drainage, paving, water, sewage, electricity and tree planting) in a city of Sao Paulo. It performs the analysis of infrastructure systems, methods for estimating costs and the process for approving projects, decomposing and characterizing the different parts. The case studies present the costs of various subsystems and the incidence of the system of urban infrastructure as a whole. It is expected to contribute to the understanding of factors that influence the cost of the systems used in medium sized cities.

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