160 research outputs found

    Analytical and experimental FWHM of a gamma camera: theoretical and practical issues

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    It is well known that resolution on a gamma camera varies as a function of distance, scatter and the camera\u2019s characteristics (collimator type, crystal thickness, intrinsic resolution etc). Manufacturers frequently provide only a few pre-calculated resolution values (using a line source in air, 10\u201315 cm from the collimator surface and without scattering). However, these are typically not obtained in situations resembling a clinical setting. From a diagnostic point of view, it is useful to know the expected resolution of a gamma camera at a given distance from the collimator surface for a particular setting in order to decide whether it is worth scanning patients with \u201csmall lesion\u201d or not. When dealing with absolute quantification it is also mandatory to know precisely the expected resolution and its uncertainty in order to make appropriate corrections. Aim. Our aims are: to test a novel mathematical approach, the cubic spline interpolation, for the extraction of the full width at half maximum (FWHM) from the acquisition of a line source (experimental resolution) also considering measurement uncertainty; to compare it with the usually adopted methods such as the gaussian approach; to compare it with the theoretical resolution (analytical resolution) of a gamma camera at different distances; to create a web-based educational program with which to test these theories. Methods. Three mathematical methods (direct calculation, global interpolation using gaussian and local interpolation using splines) for calculatingFWHMfroma line source (planar scintigraphy) were tested and compared. A NEMA Triple Line Source Phantom was used to obtain static images both in air and with different scattering levels. An advanced, open-source software (MATLAB/Octave and PHP based) was created \u201cad hoc\u201d to obtain and compareFWHMvalues and relative uncertainty. Results and Conclusion. Local interpolation using splines proved faster and more reliable than the usually-adopted Gaussian interpolation. The proposed freely available software proved effective in assessing bothFWHMand its uncertainty

    Multi-Objective Optimization of a Vapor Compression Portable Cooler

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    Sentinel-2 Data Analysis and Comparison with UAV Multispectral Images for Precision Viticulture

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    Precision viticulture (PV) requires the use of technologies that can detect the spatial and temporal variability of vineyards and, at the same time, allow useful information to be obtained at sustainable costs. In order to develop a cheap and easy-to-handle operational monitoring scheme for PV, the aim of this work was to evaluate the possibility of using Sentinel-2 multispectral images for long-term vineyard monitoring through the Normalized Difference Vegetation Index (NDVI). Vigour maps of two vineyards located in northeastern Italy were computed from satellite imagery and compared with those derived from UAV multispectral images; their correspondence was evaluated from qualitative and statistical points of view. To achieve this, the UAV images were roughly resampled to 10 m pixel size in order to match the spatial resolution of the satellite imagery. Preliminary results show the potential use of open source Sentinel-2 platforms for monitoring vineyards, highlighting links with the information given in the agronomic bulletins and identifying critical areas for crop production. Despite the large differences in spatial resolution, the results of the comparison between the UAV and Sentinel-2 data were promising. However, for long-term vineyard monitoring at territory scale, further studies using multispectral sensor calibration and groundtruth data are required

    Projeto e estudo de viabilidade técnica e financeira da correção do fator de potência em indústria têxtil utilizando bancos de capacitores

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    TCC (graduação) - Universidade Federal de Santa Catarina. Centro Tecnológico. Engenharia Elétrica.O fator de potência é um índice que indica a eficiência na utilização da energia elétrica. Este índice é monitorado pelas concessionárias de energia elétrica e os consumidores industriais que apresentam um baixo fator de potência estão sujeitos a multas incidentes mensalmente nas faturas. O objetivo deste trabalho é apresentar uma metodologia de projeto e um estudo de viabilidade técnica e financeira da correção de fator de potência utilizando bancos de capacitores. Para o desenvolvimento do estudo de caso, escolheu-se uma indústria do setor têxtil, onde foi projetado um sistema de correção do fator de potência fundamentado na caracterização da empresa, nos registros de consumo proveniente de faturas e relatórios de memória de massa, e em medições in loco. O sistema projetado, no entanto, não foi implementado devido a um sistema existente, similar àquele projetado. Foram coletados dados de consumo anteriores e posteriores à implementação do sistema existente, ocorrida em 11/2015. Também foram realizadas medições das grandezas elétricas com este sistema desligado e ligado, visando a análise das variáveis elétricas. No quesito financeiro, foi realizada a análise de viabilidade financeira da implementação do sistema projetado, considerando sua implementação em 11/2015. A instalação do sistema existente elevou o fator de potência durante todo o ciclo diário de operação da indústria, alterando a média mensal deste índice de 0,78 para 0,94. No âmbito financeiro, o investimento apresentou, em 10 anos, um VPL de R416.589,17,TIRde1805 416.589,17, TIR de 1805% a.a. e um tempo de Payback Descontado de 5 meses. Portanto, a utilização de sistemas de correção de fator de potência por meio de bancos de capacitores, conforme metodologia de projeto exposta, é considerada tecnicamente e financeiramente viável.Power factor is an index that indicates the efficiency in the use of electrical energy. This index is monitored by electricity utilities and industrial consumers presenting a low power factor are subject to monthly fines. The objective of this work is to present a design methodology and a technical and financial viability study of power factor correction using capacitor banks. For the development of the case study, a textile industry company was chosen, where a power factor correction system was designed based on the company characterization, consumption records from invoices and reports of mass memory, and on-site measurements. The designed system, however, was not implemented due to an existing system, similar to the one designed. Consumption data were collected from before and after the implementation of the existing system, which occurred on 11/2015. Measurements of the electrical parameters were also carried out with this system turned off and on, aiming the analysis of the electric variables. Regarding the financial matter, the financial viability analysis of the implementation of the designed system was carried out, considering its implementation in 11/2015. The installation of the existing system raised the power factor throughout industry's daily operating cycle, changing the monthly average of this index from 0.78 to 0.94. In the financial matter, the investment presented, in 10 years, an NPV of R 416,589.17, IRR of 1805% pa. and a Discounted Payback time of 5 months. Therefore, the use of power factor correction systems by means of capacitor banks, according to the exposed design methodology, is considered technically and financially viable

    Mecanismos de governança corporativa na pequena empresa familiar

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    Esta dissertação tem como objetivo descrever e analisar como o fenômeno da governança corporativa articula mecanismos de gestão e impacta na dinâmica de uma pequena organização familiar. Para isso, utilizou-se as perspectivas de Fan (2001) e Silva Junior (2006), que tratam da governança corporativa, e de Chandler (1994), para empresas familiares. Através de abordagem qualitativa com ênfase em um estudo de caso, uma triangulação de dados foi realizada, utilizando a entrevista semiestruturada, observação assistemática ou livre e pesquisa de documentos, e a análise dos dados foi realizada por análise de conteúdo. Verificou-se a presença do fenômeno da governança por intermédio da identificação dos fatores de diferenciação, resultando na implantação de mecanismos de governança ao longo do ciclo de vida da organização familiar, o que possibilitou mudanças em seu controle, no seu processo sucessório e na sua profissionalização. Quanto ao controle, foram verificados que os mecanismos de “manutenção do status quo”, “aconselhamento profissional”, “sinergia de interesses”, “regulamentação financeira da sociedade”, “atribuições e responsabilidades”, “alinhamento de interesses do negócio” e “proteção do empreendimento familiar” possibilitaram a modificação e manutenção do controle da empresa com os sócios. Quanto ao eixo da profissionalização, foi verificado que os mecanismos de “regulamentação financeira da sociedade”, “atribuições e responsabilidades”, “alinhamento de interesses do negócio”, “proteção do empreendimento familiar” e “atenção aos interesses dos stakeholders” foram responsáveis por prover as modificações neste quesito e indicar que a empresa caminha no sentido de se profissionalizar. Quanto ao processo sucessório, verificou-se que a terceira geração não tem interesse na empresa, o que podem resultar na contratação de um profissional externo para gerir a mesma, respeitando a questão dos valores familiares e a cultura organizacional ou conduzir à sucessão recursiva. Aparentemente, observou-se que a segunda questão foi mais evidente, visto que a saída do último irmão do negócio culmina com a venda da empresa familiar, gerando duas alternativas: a compra da empresa por um grupo de sócios ou outra empresa não familiar, o que resultaria na “morte” da empresa enquanto empresa familiar; ou a sua compra por outra família ou empresa familiar, preservando sua classificação inicial.This thesis aims to describe and analyze how the phenomenon of corporate governance articulates management mechanisms and impacts the dynamics of a small family organization. For this, we used the perspectives of Fan (2001) and Silva Junior (2006), dealing with corporate governance, and Chandler (1994), for family businesses. Through qualitative approach with emphasis on a case study, triangulation of data was performed using a semi-structured interview, unsystematic or free observation and document research, and data analysis was performed by content analysis. There was the presence of the phenomenon of governance through the identification of differentiation factors, resulting in the deployment of governance mechanisms throughout the life cycle of the family organization, which enabled changes in your control, in its succession process and its professionalization. As the control, were observed that the mechanisms of "status quo", "professional advice", "synergy of interests", "financial rules of society", "duties and responsibilities", "alignment of interests of the business" and "protection of the family business "allowed the modification and maintenance of control of the company with partners. For axis of professionalization, it was found that the mechanisms of "financial rules of society", "duties and responsibilities", "alignment of interests of the business", "protection of the family business" and "attention to the interests of stakeholders" were responsible for provide changes in this regard and indicate that the company moves towards becoming professional. As to the succession process, it was found that the third generation has no interest in the company, which can result in hiring an outside professional to manage the same, respecting the issue of family values and organizational culture or lead to recursive sequence. Apparently, it was observed that the second question was more evident as the output of the last brother of the business culminating in the sale of the family business, generating two alternatives: the purchase of the company by a group of partners or other non-family business, the would result in the "death" of the company as a family business; or your purchase by another family or family business, preserving its original classification

    Oversampling errors in multimodal medical imaging are due to the Gibbs effect

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    To analyse multimodal 3-dimensional medical images, interpolation is required for resampling which - unavoidably - introduces an interpolation error. In this work we consider three segmented 3-dimensional images resampled with three different neuroimaging software tools for comparing undersampling and oversampling strategies and to identify where the oversampling error lies. The results indicate that undersampling to the lowest image size is advantageous in terms of mean value per segment errors and that the oversampling error is larger where the gradient is steeper, showing a Gibbs effect

    Size and structure of the sequence space of repeat proteins

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    The coding space of protein sequences is shaped by evolutionary constraints set by requirements of function and stability. We show that the coding space of a given protein family-the total number of sequences in that family-can be estimated using models of maximum entropy trained on multiple sequence alignments of naturally occuring amino acid sequences. We analyzed and calculated the size of three abundant repeat proteins families, whose members are large proteins made of many repetitions of conserved portions of *30 amino acids. While amino acid conservation at each position of the alignment explains most of the reduction of diversity relative to completely random sequences, we found that correlations between amino acid usage at different positions significantly impact that diversity. We quantified the impact of different types of correlations, functional and evolutionary, on sequence diversity. Analysis of the detailed structure of the coding space of the families revealed a rugged landscape, with many local energy minima of varying sizes with a hierarchical structure, reminiscent of fustrated energy landscapes of spin glass in physics. This clustered structure indicates a multiplicity of subtypes within each family, and suggests new strategies for protein design.Fil: Marchi, Jacopo. Ecole Normale Supérieure; FranciaFil: Galpern, Ezequiel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Espada, Rocio. PSL University; FranciaFil: Ferreiro, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Walczak, Aleksandra M.. Ecole Normale Supérieure; FranciaFil: Mora, Thierry. Ecole Normale Supérieure; Franci

    Composição de Agentes EBDI: Integração WASABI-Jason

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    Emoções assumem um papel muito importante no processo de tomada de decisão de seres humanos e é natural que a sua utilização torne-se um campo bastante fértil na área de Inteligência Artificial, seja com o intuito de aproximar o comportamentode agentes computacionais ao de humanos, ou simplesmente para aprimorar a relação humano-computador. Este trabalho apresenta a integração do simulador de emoções WASABI com o arcabouço para agentes BDI JASON, para prover agentes emocionais. Os resultados obtidos sugerem que o desempenho dos agentes no ambiente, assim como em sociedades humanas, é suscetível não só ao seu comportamento programado, mas à sua personalidade emocional e às condições do ambiente

    In search of the old benches from the “Arcades Courtyard” of the São Paulo Law School

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    Historical reconstitution, through iconographic sources, of the appearance and architectural details of the old benches the existed in the “Arcades Courtyard” of the São Paulo Law School of the “Largo de São Francisco”, until the end of the Thirties of century XX, and attempt to locate of surviving unit of this type of furniture, to make reproductions.Reconstituição histórica, com base em fontes iconográficas, da aparência e dos detalhes arquitetônicos dos antigos bancos que ornavam o “Pátio das Arcadas” da Academia de Direito do Largo de São Francisco até o final dos anos 30 do século XX, e tentativa de localização de exemplar sobrevivente deste tipo de mobiliário, para a confecção de réplicas
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