Examinando por Autor "Vanegas, Carlos"
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Ítem Bi-curve and multi-patch smoothing with application to the shipyard industry(2007) Leiceaga, Xoán A.; Ruíz, Oscar; Vanegas, Carlos; Soto, Eva; Prieto, José; Rodríguez, Manuel; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEAlgorithms are proposed and implemented in a commercial system which allow for the C1-continuity matching between adjacent B-spline curves and B-spline patches -- These algorithms only manipulate the positions of the control points, therefore respecting the constraint imposed by the sizes of the available commercial steel plates -- The application of the algorithms respect the initial hull partition made by the designers and therefore the number and overall shape and position of the constitutive patches remains unchanged -- Algorithms were designed and tested for smoothing the union of (a) two B-spline curves sharing a common vertex, (b) two B-spline surfaces sharing a common border, and (c) four B-spline surfaces sharing a common vertex -- For this last case, an iterative heuristic degreeof-freedom elimination algorithm was implemented -- Very satisfactory results were obtained with the application of the presented algorithms in shipyards in SpainÍtem From being national and other fictions(Universidad EAFIT, 2013-07-18) Vanegas, Carlos; Universidad de AntioquiaÍtem From the history of art as a current possibility of humanism in Julius von Schlosser and Giulio Carlo Argan(Universidad EAFIT, 2014-06-10) Vanegas, Carlos; Universidad de AntioquiaÍtem Principal component and Voronoi skeleton alternatives for curve reconstruction from noisy point sets(Taylor & Francis, 2007-10) Ruíz, Óscar; Vanegas, Carlos; Cadavid, Carlos; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAESurface reconstruction from noisy point samples must take into consideration the stochastic nature of the sample -- In other words, geometric algorithms reconstructing the surface or curve should not insist in following in a literal way each sampled point -- Instead, they must interpret the sample as a “point cloud” and try to build the surface as passing through the best possible (in the statistical sense) geometric locus that represents the sample -- This work presents two new methods to find a Piecewise Linear approximation from a Nyquist-compliant stochastic sampling of a quasi-planar C1 curve C(u) : R → R3, whose velocity vector never vanishes -- One of the methods articulates in an entirely new way Principal Component Analysis (statistical) and Voronoi-Delaunay (deterministic) approaches -- It uses these two methods to calculate the best possible tape-shaped polygon covering the planarised point set, and then approximates the manifold by the medial axis of such a polygon -- The other method applies Principal Component Analysis to find a direct Piecewise Linear approximation of C(u) -- A complexity comparison of these two methods is presented along with a qualitative comparison with previously developed ones -- It turns out that the method solely based on Principal Component Analysis is simpler and more robust for non self-intersecting curves -- For self-intersecting curves the Voronoi-Delaunay based Medial Axis approach is more robust, at the price of higher computational complexity -- An application is presented in Integration of meshes originated in range images of an art piece -- Such an application reaches the point of complete reconstruction of a unified meshÍtem Statistical assessment of global and local cylinder wear(IEEE, 2007-01-01) Ruiz, Oscar; Vanegas, Carlos; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEAssessment of cylindricity has been traditionally performed on the basis of cylindrical crowns containing a set of points that are supposed to belong to a controlled cylinder. As such, all sampled points must lie within a crown. In contrast, the present paper analyzes the cylindricity for wear applications, in which a statistical trend is assessed, rather than to assure that all points fall within a given tolerance. Principal Component Analysis is used to identify the central axis of the sampled cylinder, allowing to And the actual (expected value of the) radius and axis of the cylinder. Application of k-cluster and transitive closure algorithms allow to identify particular areas of the cylinder which are specially deformed. For both, the local areas and the global cylinder, a quantile analysis allows to numerically grade the degree of deformation of the cylinder. The algorithms implemented are part of the CYLWEAR© system and used to assess local and global wear cylinders. © 2007 IEEE.Ítem Statistical Assessment of Global and Local Cylinder Wear(IEEE, 2007-06) Ruíz, Óscar; Vanegas, Carlos; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEAssessment of cylindricity has been traditionally performed on the basis of cylindrical crowns containing a set of points that are supposed to belong to a controlled cylinder – As such, all sampled points must lie within a crown. In contrast, the present paper analyzes the cylindricity for wear applications, in which a statistical trend is assessed, rather than to assure that all points fall within a given tolerance -- Principal Component Analysis is used to identify the central axis of the sampled cylinder, allowing to find the actual (expected value of the) radius and axis of the cylinder -- Application of k-cluster and transitive closure algorithms allow to identify particular areas of the cylinder which are specially deformed -- For both, the local areas and the global cylinder, a quantile analysis allows to numerically grade the degree of deformation of the cylinder -- The algorithms implemented are part of the CYLWEAR system and used to assess local and global wear cylinders