Encontrados 32 documentos, a visualizar página 1 de 4
Modelação matemática de epidemias
Plácido, Sara; Silva, João; Balsa, Carlos; Nunes, Alcina; Barros, ElisaUma epidemia é um problema de saúde pública sendo importante modelar a sua propagação para que se possa atuar sobre ela. Para realizar a modelação existem duas grandes classes de com origem no modelo predador-presa (Lotka-Volterra), utilizam equações diferenciais para modelar o (de)crescimento das populações envolvidas. Estes modelos são o modelo Suscetíveis-Infetados (SI) e o modelo Suscetíveis-Infetados- -Rec...
Segmentação de imagens radiológicas dentárias
Balsa, Carlos; Silva, Rita; Reis, IldaA imagiologia odontologia é cada vez mais utilizada como meio complementar de diagnóstico médico, de seguimento e de avaliação de planos de tratamento. A radiografia dentária também se tem revelado um instrumento imagiológico valioso na área da odontologia forense por permitir a identificação de cadáveres humanos, especialmente em circunstâncias adversas. Em odontologia, a segmentação de imagem médica obtida po...
Inexact subspace iteration to accelerate the solution of linear systems with mu...
Balsa, CarlosWe analyze the convergence and propose some strategy to monitor an inexact subspace iteration type of algorithm called BlockCGSI. This algorithm is purely iterative and combines the block Conjugate Gradient (blockCG) algorithm with the Subspace Iteration. We proceed to an inner-outer convergence analyze and exploit the possibility of reducing the total amount of computational work by controlling the a...
A comparative study of two optimization clustering techniques on unemployment data
Barros, Elisa; Nunes, Alcina; Balsa, CarlosAn important strategy for data classi cation consists in organising data points in clusters. The k-means is a traditional optimisation method applied to cluster data points. Using a labour market database, we suggest the application of an alternative method based on the computation of the dominant eigenvalue of a matrix related with the distance among data points. This approach presents results consistent with ...
Clustering techniques applied on cross-cectional unemployment data
Balsa, Carlos; Nunes, Alcina; Barros, ElisaUsing a cross-section database that observes the Portuguese labour market in two different phases of the business cycle, the present paper aims to address the issue of the segmentation of the Portuguese labour market taking into account the heterogeneity resulting from different unemployment characteristics observed along the Portuguese geographical space and applying two optimization clustering methods: the k-...
Graphical simulation of numerical algorithms : an approach based on code instru...
Balsa, Carlos; Alves, Luís M.; Pereira, Maria João; Rodrigues, Pedro; Lopes, Rui PedroWe want to create a working tool for mathematics teachers and a corresponding learning tool for students, namely a graphical simulator of mathematical algorithms (GraSMa). To achieve it we try two different strategies. We started by annotate manually the original algorithm with inspector functions. Now we are testing a new approach that aims to automatically annotate the original code with inspector functions. ...
Graphical simulation of numerical algorithms - an aproach based on code instru...
Balsa, Carlos; Alves, Luís M.; Pereira, Maria João; Rodrigues, Pedro João; Lopes, Rui PedroWe want to create a working tool for mathematics teachers and a corresponding learning tool for students, namely a graphical simulator of mathematical algorithms (GraSMa). To achieve it we try two different strategies. We started by annotating manually the original algorithm with inspector functions. Now we are testing a new approach that aims at automatically annotating the original code with inspector functio...
Numerical analysis of blood flow in stenosed channels
Ferreira, Stephanie; Dias, Ricardo P.; Balsa, Carlos; Fernandes, Carla S.Wall shear rates and pressure developed in blood vessels play an important role on the development of some clinical problems such as atherosclerosis and thrombosis. In the present work, blood flow behaviour was numerically studied in simplified domains and several relevant local properties were determined. We believe that the obtained results will be useful in the interpretation of some phenomena associated to ...
Resolução de sistemas de equações algébricas, em mecânica dos fluídos computaci...
Balsa, Carlos Jorge da RochaDissertação apresentada para obtenção do grau de Mestre emMétodos Computacionais em Ciência e Engenharia, na Faculdade de Ciências da Universidade do Porto
Inexact subspace iteraction to accelerate the solution of linear system with mu...
Balsa, Carlos Jorge da RochaTese de doutoramento. Ciências de Engenharia. 2005. Faculdade de Engenharia. Universidade do Porto, Institut National Polytechnique de Toulouse
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