Examinando por Autor "Ruiz, O."
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Ítem Accelerated Thermal Simulation for Three-Dimensional Interactive Optimization of Computer Numeric Control Sheet Metal Laser Cutting(American Society of Mechanical Engineers (ASME), 2017-12-21) Mejía, D.; Moreno, Aitor; Arbelaiz, Ander; Posada, Jorge; Ruiz, O.; Chopitea, Raúl; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Advanced HCI and 3D web over low performance devices(CEUR-WS, 2012-01-01) Oyarzun, D.; Del Pozo, A.; Congote, J.E.; Olaizola, I.G.; Sainz, I.; Leturia, I.; Arregi, X.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis position paper presents the authors' goals on advanced human computer interaction and 3D Web. Previous work on speech, natural language processing and visual technologies has achieved the development of the BerbaTek language learning demonstrator, a 3D virtual tutor that supports Basque language students through spoken interaction. Next steps consist on migrating all the system to multidevice web technologies. This paper shows the architecture defined and the steps to be performed in the next months.Ítem Analytical method for the kinetostatic analysis of the second-class RRR assur group allowing for friction in the kinematic pairs(Springer Berlin Heidelberg, 2010-07-01) Durango, S.; Calle, G.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThe calculation of forces in the kinematic pairs of mechanisms by inverse dynamics is usually performed without friction considerations. In practice, when examination of articulated mechanisms takes into account friction, the solution of the inverse dynamics results in a complex procedure. If a modular approach for the inverse dynamics is used, then exact solutions are available, but not necessarily are practical. For example, the analytical solution for a second-class first-type Assur group is a 16th degree equation. Previous researches proposed an approximated but practical (graphical) method to calculate the forces on the kinematic pairs taking into account the friction forces. In this article, an analytical interpretation of the Artobolevski approximated method is developed for the second-class Assur group with three rotational pairs. The final results for the reactions calculated with the implemented method present a good approximation with respect to the graphical solution. Future work should consider friction forces not only in second-class groups with rotational joints, but also in second-class groups with prismatic joints and high-class Assur groups. Copyright © 2010 by ABCM.Ítem Approximation of the Mechanical Response of Large Lattice Domains Using Homogenization and Design of Experiments(Universitatea Politehnica Bucuresti, 2020-06-01) Montoya, D.; Acosta, D.; Cortes, C.; Pareja, J.; Moreno, Aitor; Posada, Jorge; Ruiz, O.; Montoya, D.; Acosta, D.; Cortes, C.; Pareja, J.; Moreno, Aitor; Posada, Jorge; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)Ítem Approximation of the Mechanical Response of Large Lattice Domains Using Homogenization and Design of Experiments(Universitatea Politehnica Bucuresti, 2020-06-01) Montoya, D.; Acosta, D.; Cortes, C.; Pareja, J.; Moreno, Aitor; Posada, Jorge; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosÍtem Approximation of the Mechanical Response of Large Lattice Domains Using Homogenization and Design of Experiments(Universitatea Politehnica Bucuresti, 2020-06-01) Montoya, D.; Acosta, D.; Cortes, C.; Pareja, J.; Moreno, Aitor; Posada, Jorge; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Digital material laboratory: Wave propagation effects in open-cell aluminium foams(PERGAMON-ELSEVIER SCIENCE LTD, 2012-09-01) Saenger, E. H.; Uribe, D.; Jaenicke, R.; Ruiz, O.; Steeb, H.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis paper is concerned with numerical wave propagation effects in highly porous media using digitized images of aluminium foam. Starting point is a virtual material laboratory approach. The aluminium foam microstructure is imaged by 3D X-ray tomography. Effective velocities for the fluid-saturated media are derived by dynamic wave propagation simulations. We apply a displacement-stress rotated staggered finite-difference grid technique to solve the elastodynamic wave equation. The used setup is similar to laboratory ultrasound measurements and computed results are in agreement with our experimental data. Theoretical investigations allow to quantify the influence of the interaction of foam and fluid during wave propagation. Together with simulations using an artificial dense foam we are able to determine the tortuosity of aluminium foam. © 2012 Elsevier Ltd. All rights reserved.Ítem Ellipse-based principal component analysis for self-intersecting curve reconstruction from noisy point sets(SPRINGER, 2011-03-01) Ruiz, O.; Vanegas, C.; Cadavid, C.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAESurface reconstruction from cross cuts usually requires curve reconstruction from planar noisy point samples. The output curves must form a possibly disconnected 1-manifold for the surface reconstruction to proceed. This article describes an implemented algorithm for the reconstruction of planar curves (1-manifolds) out of noisy point samples of a self-intersecting or nearly self-intersecting planar curve C. C:[a,b]R?R 2 is self-intersecting if C(u)=C(v), u v, u,v (a,b) (C(u) is the self-intersection point). We consider only transversal self-intersections, i.e. those for which the tangents of the intersecting branches at the intersection point do not coincide (C (u)=C(v)). In the presence of noise, curves which self-intersect cannot be distinguished from curves which nearly self-intersect. Existing algorithms for curve reconstruction out of either noisy point samples or pixel data, do not produce a (possibly disconnected) Piecewise Linear 1-manifold approaching the whole point sample. The algorithm implemented in this work uses Principal Component Analysis (PCA) with elliptic support regions near the self-intersections. The algorithm was successful in recovering contours out of noisy slice samples of a surface, for the Hand, Pelvis and Skull data sets. As a test for the correctness of the obtained curves in the slice levels, they were input into an algorithm of surface reconstruction, leading to a reconstructed surface which reproduces the topological and geometrical properties of the original object. The algorithm robustly reacts not only to statistical non-correlation at the self-intersections (non-manifold neighborhoods) but also to occasional high noise at the non-self-intersecting (1-manifold) neighborhoods. © 2010 Springer-Verlag.Ítem Ellipse-based principal component analysis for self-intersecting curve reconstruction from noisy point sets(SPRINGER, 2011-03-01) Ruiz, O.; Vanegas, C.; Cadavid, C.; Ruiz, O.; Vanegas, C.; Cadavid, C.; Universidad EAFIT. Departamento de Ciencias; Matemáticas y AplicacionesSurface reconstruction from cross cuts usually requires curve reconstruction from planar noisy point samples. The output curves must form a possibly disconnected 1-manifold for the surface reconstruction to proceed. This article describes an implemented algorithm for the reconstruction of planar curves (1-manifolds) out of noisy point samples of a self-intersecting or nearly self-intersecting planar curve C. C:[a,b]R?R 2 is self-intersecting if C(u)=C(v), u v, u,v (a,b) (C(u) is the self-intersection point). We consider only transversal self-intersections, i.e. those for which the tangents of the intersecting branches at the intersection point do not coincide (C (u)=C(v)). In the presence of noise, curves which self-intersect cannot be distinguished from curves which nearly self-intersect. Existing algorithms for curve reconstruction out of either noisy point samples or pixel data, do not produce a (possibly disconnected) Piecewise Linear 1-manifold approaching the whole point sample. The algorithm implemented in this work uses Principal Component Analysis (PCA) with elliptic support regions near the self-intersections. The algorithm was successful in recovering contours out of noisy slice samples of a surface, for the Hand, Pelvis and Skull data sets. As a test for the correctness of the obtained curves in the slice levels, they were input into an algorithm of surface reconstruction, leading to a reconstructed surface which reproduces the topological and geometrical properties of the original object. The algorithm robustly reacts not only to statistical non-correlation at the self-intersections (non-manifold neighborhoods) but also to occasional high noise at the non-self-intersecting (1-manifold) neighborhoods. © 2010 Springer-Verlag.Ítem Erratum: Ellipse-based principal component analysis for self-intersecting curve reconstruction from noisy point sets (Visual Computer DOI: 10.1007/s00371-010-0527-x)(SPRINGER, 2011-01-01) Ruiz, O.; Vanegas, C.; Cadavid, C.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE[No abstract available]Ítem Erratum: Ellipse-based principal component analysis for self-intersecting curve reconstruction from noisy point sets (Visual Computer DOI: 10.1007/s00371-010-0527-x)(SPRINGER, 2011-01-01) Ruiz, O.; Vanegas, C.; Cadavid, C.; Ruiz, O.; Vanegas, C.; Cadavid, C.; Universidad EAFIT. Departamento de Ciencias; Matemáticas y Aplicaciones[No abstract available]Ítem Evaluation of interest point detectors for image information extraction(IOS PRESS, 2012-01-01) Barandiaran, I.; Congote, J.; Goenetxea, J.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEInterest points extraction and matching is a common task in many computer vision based application, which are used in different domains, such as 3D reconstruction, object recognition, or tracking. We present an evaluation of current state of the art about interest point extraction algorithms to measure several parameters, such as detection quality, invariance to rotation and scale transformation, and computational efficiency. © 2012 The authors and IOS Press. All rights reserved.Ítem Extending marching cubes with adaptative methods to obtain more accurate iso-surfaces(Springer Verlag, 2010-01-01) Congote, J.; Moreno, A.; Barandiaran, I.; Barandiaran, J.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis work proposes an extension of the Marching Cubes algorithm, where the goal is to represent implicit functions with higher accuracy using the same grid size. The proposed algorithm displaces the vertices of the cubes iteratively until the stop condition is achieved. After each iteration, the difference between the implicit and the explicit representations is reduced, and when the algorithm finishes, the implicit surface representation using the modified cubical grid is more accurate, as the results shall confirm. The proposed algorithm corrects some topological problems that may appear in the discretization process using the original grid. © 2010 Springer-Verlag Berlin Heidelberg.Ítem Face reconstruction with structured light(INSTICC-INST SYST TECHNOLOGIES INFORMATION CONTROL & COMMUNICATION, 2011-01-01) Congote, J.; Barandiaran, I.; Barandiaran, J.; Nieto, M.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis article presents a methodology for reconstruction of 3D faces which is based on stereoscopic images of the scene using active and passive surface reconstruction. A sequence of Gray patterns is generated, which are projected onto the scene and their projection recorded by a pair of stereo cameras. The images are rectified to make coincident their epipolar planes and so to generate a stereo map of the scene. An algorithm for stereo matching is applied, whose result is a bijective mapping between subsets of the pixels of the images. A particular connected subset of the images (e.g. the face) is selected by a segmentation algorithm. The stereo mapping is applied to such a subset and enables the triangulation of the two image readings therefore rendering the (x,y,z) points of the face, which in turn allow the reconstruction of the triangular mesh of the face. Since the surface might have holes, bilateral filters are applied to have the holes filled. The algorithms are tested in real conditions and we evaluate their performance with virtual datasets. Our results show a good reconstruction of the faces and an improvement of the results of passive systems.Ítem Fast Simulation of Laser Heating Processes on Thin Metal Plates with FFT Using CPU/GPU Hardware(Universitatea Politehnica Bucuresti, 2020-05-08) Mejía, D.; Arbelaiz, Andres; Ruiz, O.; Lalinde, J.; Moreno, Aitor; Posada, Jorge; Mejía, D.; Arbelaiz, Andres; Ruiz, O.; Lalinde, J.; Moreno, Aitor; Posada, Jorge; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las ComunicacionesÍtem Fast Simulation of Laser Heating Processes on Thin Metal Plates with FFT Using CPU/GPU Hardware(Universitatea Politehnica Bucuresti, 2020-05-08) Mejía, D.; Arbelaiz, Andres; Ruiz, O.; Lalinde, J.; Moreno, Aitor; Posada, Jorge; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Geometry and Topology-based Segmentation of 2-Manifold Triangular Meshes in R3(SCIENCEDOMAIN international (SDI), 2017-05-23) Orozco, Stella; Formella, Arno; Cadavid, C.; Ruiz, O.; Osorno, Maria; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEÍtem Geometry and Topology-based Segmentation of 2-Manifold Triangular Meshes in R3(SCIENCEDOMAIN international (SDI), 2017-05-23) Orozco, Stella; Formella, Arno; Cadavid, C.; Ruiz, O.; Osorno, Maria; Orozco, Stella; Formella, Arno; Cadavid, C.; Ruiz, O.; Osorno, Maria; Universidad EAFIT. Departamento de Ciencias; Matemáticas y AplicacionesÍtem Hardware-accelerated web visualization of vector fields: Case study in oceanic currents(2012-01-01) Aristizabal, M.; Congote, J.; Segura, A.; Moreno, A.; Arregui, H.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEVisualization of vector fields plays an important role in research activities nowadays. Increasing web applications allow a fast, multi-platform and multi-device access to data. As a result, web applications must be optimized in order to be performed heterogeneously as well as on high-performance as on low capacity devices. This paper presents a hardware-accelerated scheme for integration-based flow visualization techniques, based on a hierarchical integration procedure which reduces the computational effort of the algorithm from linear to logarithmic, compared to serial integration methodologies. The contribution relies on the fact that the optimization is only implemented using the graphics application programming interface (API), instead of requiring additional APIs or plug-ins. This is achieved by using images as data storing elements instead of graphical information matrices. A case study in oceanic currents is implemented.Ítem Implementation and Visualization of Discrete Computational Geometry Using Database Managers(Engg Journals Publications, 2019-06-30) Orozco Ochoa, Stella; Ruiz, O.; Cadavid, C.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE