Examinando por Materia "Vector analysis"
Mostrando 1 - 5 de 5
Resultados por página
Opciones de ordenación
Ítem Algunas ecuaciones diferenciales en la variedad K-exponencial(Universidad EAFIT, 2014) Cartagena Marín, Carlos Mario; Loaiza Ossa, Gabriel IgnacioEn este trabajo se discute la formulación de ecuaciones diferenciales, ordinarias y estocásticas, en variedades de información estadística -- Se propone un campo vectorial sobre la variedad de información estadística k-exponencial, siendo k el índice de entropía según Kaniadakis, que defina el modelo correspondiente a la familia Gaussiana k-deformada dependiente del tiempo -- También se divulgan aspectos importantes sobre la consideración de ecuaciones diferenciales en variedades de información estadísticaÍtem Interactive visualization of volumetric data with WebGL in real-time(ACM, 2011-06) Congote, John; Kabongo, Luis; Moreno, Aitor; Segura, Alvaro; Posada, Jorge; Ruíz, Oscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis article presents and discusses the implementation of a volume rendering system for the Web, which articulates a large portion of the rendering task in the client machine -- By placing the rendering emphasis in the local client, our system takes advantage of its power, while at the same time eliminates processing from unreliable bottlenecks (e.g. network) -- The system developed articulates in efficient manner the capabilities of the recently released WebGL standard, which makes available the accelerated graphic pipeline (formerly unusable) -- The dependency on specially customized hardware is eliminated, and yet efficient rendering rates are achieved -- The Web increasingly competes against desktop applications in many scenarios, but the graphical demands of some of the applications (e.g. interactive scientific visualization by volume rendering), have impeded their successful settlement in Web scenarios -- Performance, scalability, accuracy, security are some of the many challenges that must be solved before visualWeb applications popularize -- In this publication we discuss both performance and scalability of the volume rendering by WebGL ray-casting in two different but challenging application domains: medical imaging and radar meteorologyÍtem Limits of quotients of bivariate real analytic functions(ELSEVIER, 2013-03) Molina, Sergio; Cadavid Moreno, Carlos Alberto; Vélez Caicedo, Juan Diego; Universidad EAFIT. Escuela de Ciencias y Humanidades. Grupo de Investigación Análisis Funcional y Aplicaciones; Carlos Cadavid M.(ccadavid@eafit.edu.co); Análisis Funcional y AplicacionesNecessary and sufficient conditions for the existence of limits of the form lim(x,y)→(a,b) f (x, y)/g(x, y) are given, under the hypothesis that f and g are real analytic functions near the point (a, b), and g has an isolated zero at (a, b) -- The given criterion uses a constructive version of Hensel’s Lemma which could be implemented in a computer algebra system in the case where f and g are polynomials with rational coefficients, or more generally, with coefficients in a real finite extension of the rationals -- A high level description of an algorithm for determining the existence of the limit as well as its computation is providedÍtem Sensitivity analysis in optimized parametric curve fitting(Emerald Group Publishing, 2015) Ruíz, Óscar E.; Cortés, Camilo; Acosta, Diego A.; Aristizábal, Mauricio; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEPurpose – Curve fitting from unordered noisy point samples is needed for surface reconstruction in many applications -- In the literature, several approaches have been proposed to solve this problem -- However, previous works lack formal characterization of the curve fitting problem and assessment on the effect of several parameters (i.e. scalars that remain constant in the optimization problem), such as control points number (m), curve degree (b), knot vector composition (U), norm degree (k), and point sample size (r) on the optimized curve reconstruction measured by a penalty function (f) -- The paper aims to discuss these issues -- Design/methodology/approach - A numerical sensitivity analysis of the effect of m, b, k and r on f and a characterization of the fitting procedure from the mathematical viewpoint are performed -- Also, the spectral (frequency) analysis of the derivative of the angle of the fitted curve with respect to u as a means to detect spurious curls and peaks is explored -- Findings - It is more effective to find optimum values for m than k or b in order to obtain good results because the topological faithfulness of the resulting curve strongly depends on m -- Furthermore, when an exaggerate number of control points is used the resulting curve presents spurious curls and peaks -- The authors were able to detect the presence of such spurious features with spectral analysis -- Also, the authors found that the method for curve fitting is robust to significant decimation of the point sample -- Research limitations/implications - The authors have addressed important voids of previous works in this field -- The authors determined, among the curve fitting parameters m, b and k, which of them influenced the most the results and how -- Also, the authors performed a characterization of the curve fitting problem from the optimization perspective -- And finally, the authors devised a method to detect spurious features in the fitting curve -- Practical implications – This paper provides a methodology to select the important tuning parameters in a formal manner -- Originality/value - Up to the best of the knowledge, no previous work has been conducted in the formal mathematical evaluation of the sensitivity of the goodness of the curve fit with respect to different possible tuning parameters (curve degree, number of control points, norm degree, etc.)Ítem Spectral-based mesh segmentation(Springer Paris, 2016) Mejía, Daniel; Cadavid, Carlos A.; Ruíz-Salguero, Óscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEIn design and manufacturing, mesh segmentation is required for FACE construction in boundary representation (BRep), which in turn is central for featurebased design, machining, parametric CAD and reverse engineering, among others -- Although mesh segmentation is dictated by geometry and topology, this article focuses on the topological aspect (graph spectrum), as we consider that this tool has not been fully exploited -- We preprocess the mesh to obtain a edgelength homogeneous triangle set and its Graph Laplacian is calculated -- We then produce a monotonically increasing permutation of the Fiedler vector (2nd eigenvector of Graph Laplacian) for encoding the connectivity among part feature submeshes -- Within the mutated vector, discontinuities larger than a threshold (interactively set by a human) determine the partition of the original mesh -- We present tests of our method on large complex meshes, which show results which mostly adjust to BRep FACE partition -- The achieved segmentations properly locate most manufacturing features, although it requires human interaction to avoid over segmentation -- Future work includes an iterative application of this algorithm to progressively sever features of the mesh left from previous submesh removals