Examinando por Materia "methodology"
Mostrando 1 - 14 de 14
Resultados por página
Opciones de ordenación
Ítem Creation of a three-dimensional model of the mandible and the TMJ in vivo by means of the finite element method.(Quintessenz Verlags GmbH, 2002-04-01) Castaño MC; Zapata U; Pedroza A; Jaramillo JD; Roldán S; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)The aim of this study was to develop a three-dimensional finite element model of the mandible, including its TMJ. The model consisted of 7942 nodes and 41,010 elements, which were obtained from a convergence test, done to minimize the result error. It included cancellous and cortical bone, periodontal ligament, masticatory muscles (masseters, temporalis, lateral and internal pterygoids), teeth and the articular disk. All characteristics such as dental, mandibular, and muscle geometry were obtained from a computerized tomography (CT) of a living person. CT sections were scanned and digitized with a CAD software program. After images were adequately assembled, a vertical tracing was done which allowed the definition of a three-dimensional mesh. Modeling of teeth was carried out independently and the periodontal ligament was later included, limiting the alveolar area. Muscles were modeled based on flat-scale photographs and total muscle force was distributed in multiple vectors. The articular disk was generated having 2 mm of thickness with the combination of spring-type (axial stiffness) and gap-type (contact) elements. The model was then analyzed with finite element method (FEM) software where a mesh was generated and values for Poisson's ratio, elasticity, and shear modulus were assigned. These were orthotropic for cancellous and cortical bone, and isotropic for dentin, periodontal ligament, articular disk, and temporal bone. The boundary conditions were defined restricting the nodes on the periphery of the temporal bone. It was therefore possible to generate a three-dimensional finite element model based on information obtained in vivo.Ítem The electrochemical elimination of coliforms from water using BBD/Ti or graphite anodes: A comparative study(International Water Association Publishing, 2018-04-01) Gil Pavas, E.; Arbelaez, Paula Eliana; Medina, J.; Dobrosz-Gómez, I.; Angel Gomez-Garcia, Miguel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosThe elimination of total and fecal coliforms, from raw surface water, was carried out by electrochemical oxidation using either boron doped diamond (BDD/Ti) or graphite (GP) anodes, in a chloride-free medium. The optimal values of the operation parameters, maximizing the coliform elimination percentage, were determined using statistical experimental design. The current density ( j: 2-20 mA/cm2), the conductivity (s: 500-900 µS/cm) and the anode materials (An) were considered as variables to perform the Box-Behnken experimental design together with the response surface methodology analysis for optimization. The statistical analysis indicated that, in the evaluated range, the disinfection efficiency increased with an increase in j and decreased with an increase in s. The following optimal conditions for the elimination of total and fecal coliforms were found: j: 10 mA/cm2, s: 500 µS/cm and BDD/Ti used as anode material. The BDD/Ti electrode let to achieve complete coliform elimination after ca. 20 min of reaction while the GP one needed ca. 27 min. In water treated with both BDD/Ti and GP anode, after 7 days, any coliforms growth was observed. As a result of the oxidation process, the total organic carbon and nitrite concentration decreased while nitrate concentration increased. © IWA Publishing 2018.Ítem The electrochemical elimination of coliforms from water using BBD/Ti or graphite anodes: A comparative study(International Water Association Publishing, 2018-04-01) Gil Pavas, E.; Arbelaez, Paula Eliana; Medina, J.; Dobrosz-Gómez, I.; Angel Gomez-Garcia, Miguel; Gil Pavas, E.; Arbelaez, Paula Eliana; Medina, J.; Dobrosz-Gómez, I.; Angel Gomez-Garcia, Miguel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)The elimination of total and fecal coliforms, from raw surface water, was carried out by electrochemical oxidation using either boron doped diamond (BDD/Ti) or graphite (GP) anodes, in a chloride-free medium. The optimal values of the operation parameters, maximizing the coliform elimination percentage, were determined using statistical experimental design. The current density ( j: 2-20 mA/cm2), the conductivity (s: 500-900 µS/cm) and the anode materials (An) were considered as variables to perform the Box-Behnken experimental design together with the response surface methodology analysis for optimization. The statistical analysis indicated that, in the evaluated range, the disinfection efficiency increased with an increase in j and decreased with an increase in s. The following optimal conditions for the elimination of total and fecal coliforms were found: j: 10 mA/cm2, s: 500 µS/cm and BDD/Ti used as anode material. The BDD/Ti electrode let to achieve complete coliform elimination after ca. 20 min of reaction while the GP one needed ca. 27 min. In water treated with both BDD/Ti and GP anode, after 7 days, any coliforms growth was observed. As a result of the oxidation process, the total organic carbon and nitrite concentration decreased while nitrate concentration increased. © IWA Publishing 2018.Ítem mantisGRID: a grid platform for DICOM medical images management in Colombia and Latin America.(SPRINGER, 2011-04-01) Garcia Ruiz M; García, A.; Ruiz Ibañez C; Gutierrez Mazo JM; Ramirez Giraldo JC; Pelaez Echavarria A; Valencia Diaz E; Pelaez Restrepo G; Montoya Munera EN; Garcia Loaiza B; Gomez Gonzalez S; Garcia Ruiz M; García, A.; Ruiz Ibañez C; Gutierrez Mazo JM; Ramirez Giraldo JC; Pelaez Echavarria A; Valencia Diaz E; Pelaez Restrepo G; Montoya Munera EN; Garcia Loaiza B; Gomez Gonzalez S; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las ComunicacionesThis paper presents the mantisGRID project, an interinstitutional initiative from Colombian medical and academic centers aiming to provide medical grid services for Colombia and Latin America. The mantisGRID is a GRID platform, based on open source grid infrastructure that provides the necessary services to access and exchange medical images and associated information following digital imaging and communications in medicine (DICOM) and health level 7 standards. The paper focuses first on the data abstraction architecture, which is achieved via Open Grid Services Architecture Data Access and Integration (OGSA-DAI) services and supported by the Globus Toolkit. The grid currently uses a 30-Mb bandwidth of the Colombian High Technology Academic Network, RENATA, connected to Internet 2. It also includes a discussion on the relational database created to handle the DICOM objects that were represented using Extensible Markup Language Schema documents, as well as other features implemented such as data security, user authentication, and patient confidentiality. Grid performance was tested using the three current operative nodes and the results demonstrated comparable query times between the mantisGRID (OGSA-DAI) and Distributed mySQL databases, especially for a large number of records.Ítem mantisGRID: a grid platform for DICOM medical images management in Colombia and Latin America.(SPRINGER, 2011-04-01) Garcia Ruiz M; García, A.; Ruiz Ibañez C; Gutierrez Mazo JM; Ramirez Giraldo JC; Pelaez Echavarria A; Valencia Diaz E; Pelaez Restrepo G; Montoya Munera EN; Garcia Loaiza B; Gomez Gonzalez S; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)This paper presents the mantisGRID project, an interinstitutional initiative from Colombian medical and academic centers aiming to provide medical grid services for Colombia and Latin America. The mantisGRID is a GRID platform, based on open source grid infrastructure that provides the necessary services to access and exchange medical images and associated information following digital imaging and communications in medicine (DICOM) and health level 7 standards. The paper focuses first on the data abstraction architecture, which is achieved via Open Grid Services Architecture Data Access and Integration (OGSA-DAI) services and supported by the Globus Toolkit. The grid currently uses a 30-Mb bandwidth of the Colombian High Technology Academic Network, RENATA, connected to Internet 2. It also includes a discussion on the relational database created to handle the DICOM objects that were represented using Extensible Markup Language Schema documents, as well as other features implemented such as data security, user authentication, and patient confidentiality. Grid performance was tested using the three current operative nodes and the results demonstrated comparable query times between the mantisGRID (OGSA-DAI) and Distributed mySQL databases, especially for a large number of records.Ítem Methodological Approach for the Study and Representation of Complex Behaviors on Electricity Markets(Universidad EAFIT, 2016-11-22) Valencia-Calvo, Johnny; Franco-Cardona, Carlos Jaime; Olivar-Tost, Gerard; Dyner, IsaacÍtem Pretextos, una 'acupuntura pedagógica'(Universidad EAFIT, 2024-08-23) Sommer, Doris; Mena-Rodríguez, Victoria Eugenia; Universidad EAFITÍtem Sensitivity, uncertainty and identifiability analyses to define a dengue transmission model with real data of an endemic municipality of Colombia(Public Library of Science, 2020-01-01) Lizarralde-Bejarano, D.P.; Rojas-Díaz, D.; Arboleda-Sánchez, S.; Puerta-Yepes, M.E.; Lizarralde-Bejarano, D.P.; Rojas-Díaz, D.; Arboleda-Sánchez, S.; Puerta-Yepes, M.E.; Universidad EAFIT. Departamento de Ciencias; Matemáticas y AplicacionesDengue disease is a major problem for public health surveillance entities in tropical and subtropical regions having a significant impact not only epidemiological but social and economical. There are many factors involved in the dengue transmission process. We can evaluate the importance of these factors through the formulation of mathematical models. However, the majority of the models presented in the literature tend to be overparameterized, with considerable uncertainty levels and excessively complex formulations. We aim to evaluate the structure, complexity, trustworthiness, and suitability of three models, for the transmission of dengue disease, through different strategies. To achieve this goal, we perform structural and practical identifiability, sensitivity and uncertainty analyses to these models. The results showed that the simplest model was the most appropriate and reliable when the only available information to fit them is the cumulative number of reported dengue cases in an endemic municipality of Colombia. © 2020 Lizarralde-Bejarano et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Ítem Shack-Hartmann centroid detection using the spiral phase transform(OSA - The Optical Society of America, 2012-01-01) Vargas, J.; Restrepo, R.; Estrada, J.C.; Sorzano, C.O.S.; Du, Y.-Z.; Carazo, J.M.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaWe present a Shack-Hartmann (SH) centroid detection algorithm capable to measure in presence of strong noise, background illumination and spot modulating signals, which are typical limiting factors of traditional centroid detection algorithms. The proposed method is based on performing a normalization of the SH pattern using the spiral phase transform method and Fourier filtering. The spot centroids are then obtained using global thresholding and weighted average methods. We have tested the algorithm with simulations and experimental data obtaining satisfactory results. A complete MATLAB package that can reproduce all the results can be downloaded from [http://goo.gl/o2JhD]. © 2012 Optical Society of America.Ítem Shack-Hartmann spot dislocation map determination using an optical flow method(OPTICAL SOC AMER, 2014-01-27) Vargas, J.; Restrepo, R.; Belenguer, T.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaWe present a robust, dense, and accurate Shack-Hartmann spot dislocation map determination method based on a regularized optical flow algorithm that does not require obtaining the spot centroids. The method is capable to measure in presence of strong noise, background illumination and spot modulating signals, which are typical limiting factors of traditional centroid detection algorithms. Moreover, the proposed approach is able to face cases where some of the reference beam spots have not a corresponding one in the distorted Hartmann diagram, and it can expand the dynamic range of the Shack-Hartmann sensor unwrapping the obtained dense dislocation maps. We have tested the algorithm with both simulations and experimental data obtaining satisfactory results. A complete MATLAB package that can reproduce all the results can be downloaded from [http://goo.gl/XbZVOr]. © 2014 Optical Society of America.Ítem Speckle photography with different pupils in a multiple-exposure scheme(OPTICAL SOC AMER, 2000-01-01) Angel, L; Tebaldi, M; Bolognini, N; Trivi, M; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaThe use of different multiple-aperture pupils for recording each image in speckle photography is proposed. The introduction of suitable spatial frequency carriers, by internally modulating imaged speckles, allows one to selectively isolate or combine the spectral content of different images into spatially separated regions in the Fourier plane. Theoretical and experimental results extend the speckle photography technique to the depiction of several specklegrams of multiple uniform in-plane displacements. In this case, because different pupils are considered for recording, the cross-correlation functions for the amplitudes and intensities in the image plane are calculated on the basis of the statistical properties of the object. Also, the ensemble-average intensity in the Fourier plane is analytically derived, and fringe visibility is investigated. © 2000 Optical Society of America.Ítem Strengthening the capacities of communities in the Serranía de San Lucas(Universidad EAFIT, 2023) Eslava Gómez, Adolfo; Vélez Zapata, Sara; Valencia Vélez, Sergio Andrés; Ríos López, Mariela; Castaño Quintero, Maria Elizabeth; Tovar Seña, Manuel de Jesús; Palau Vasco, Jesús Alexander; Tobón Parra, Jorge; Muñoz Benítez, Carolina; Londoño, Yeison; Zamudio Mir, Maria Camila; Uribe López, Mauricio; Vargas Forero, Gonzalo; Universidad EAFITThis video describes the different methodological tools used to develop the “San Lucas: Living Territory” project, which aimed to strengthen community capacity for decision-making on sustainable use of the Serranía de San Lucas. This methodology brought together investigative elements from various disciplines to identify socially problematic situations and possible solutions and agreements, based on community knowledge. It highlights the participatory nature of community meetings and their playful component, where all voices were recognized and valued. Additionally, it used QCA to analyze conditions determining the sustainable use of the forest.Ítem El valor social de las organizaciones, bajo el análisis de Bien Plus(Universidad EAFIT, 2023-03-27) Restrepo, Juan Diego; Universidad EAFITAtender la inquietud de uno de los grandes grupos del sector comercial del país llevó a varios investigadores de la Universidad EAFIT a crear un método de medición y gestión del impacto que este tipo de empresas tiene en la sociedad. El propósito ahora es aplicarlo a diversas instituciones.Ítem Volume Visual Attention Maps (VVAM) in ray-casting rendering(IOS Press, 2012-01-01) Beristain, A.; Congote, J.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis paper presents an extension visual attention maps for volume data visualization, where eye fixation points become rays in the 3D space, and the visual attention map becomes a volume. This Volume Visual Attention Map (VVAM) is used to interactively enhance a ray-casting based direct volume rendering (DVR) visualization. The practical application of this idea into the biomedical image visualization field is explored for interactive visualization. © 2012 The authors and IOS Press. All rights reserved.