Examinando por Materia "Functions"
Mostrando 1 - 8 de 8
Resultados por página
Opciones de ordenación
Ítem Analytical solution for transient flow of a generalized bingham fluid with memory in a movable tube using computer algebra(SPRINGER, 2007-01-01) Ospina, Juan; Velez, Mario; Ospina, Juan; Velez, Mario; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónA rheological linear model for a certain generalized Bingham fluid with rheological memory, which flows in a movable tube is proposed and analytically solved. The model is a system of two linear and coupled partial differential equations with integral memory. We apply the Laplace transform method making the inverse transform by means of the Bromwich integral and the theorem of residues and the analytical solution are obtained using computer algebra. We deduce the explicit forms of the velocity and stress profiles for the generalized Bingham fluid in terms of Bessel and Struve functions. Various limit cases are obtained and the standard Hagen-Poiseuille and Buckingham-Reiner equations are recovered from more general equations. This works shows the powerful of Maple to solve complex rheological problems in an analytical form as it is presented here by the first time. © Springer-Verlag Berlin Heidelberg 2007.Ítem Design of computer experiments applied to modeling of compliant mechanisms for real-time control(Springer London, 2013-07) Acosta, Diego A.; Restrepo, David; Durango, Sebastián; Ruíz, Óscar E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis article discusses the use of design of computer experiments (DOCE) (i.e., experiments run with a computer model to find how a set of inputs affects a set of outputs) to obtain a force–displacement meta-model (i.e., a mathematical equation that summarizes and aids in analyz-ing the input–output data of a DOCE) of compliant mechanisms (CMs) -- The procedure discussed produces a force–displacement meta-model, or closed analytic vector function, that aims to control CMs in real-time -- In our work, the factorial and space-filling DOCE meta-model of CMs is supported by finite element analysis (FEA) -- The protocol discussed is used to model the HexFlex mechanism functioning under quasi-static conditions -- The HexFlex is a parallel CM for nano-manipulation that allows six degrees of freedom (x, y, z, hx, hy, hz) of its moving platform -- In the multi-linear model fit of the HexFlex, the products or inter-actions proved to be negligible, yielding a linear model (i.e.,linear in the inputs) for the operating range -- The accuracy of the meta-model was calculated by conducting a set of computer experiments with random uniform distribution of the input forces -- Three error criteria were recorded comparing the meta-model prediction with respect to the results of the FEA experiments by determining: (1) maximum of the absolute value of the error, (2) relative error, and (3) root mean square error -- The maximum errors of our model are lower than high-precision manufacturing tolerances and are also lower than those reported by other researchers who have tried to fit meta-models to the HexFlex mechanismÍtem Ellipse-based Principal Component Analysis for Self-intersecting Curve Reconstruction from Noisy Point Sets(Springer Berlin Heidelberg, 2011) Ruíz, 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 1manifold for the surface reconstruction to proceed -- This article describes an implemented algorithm for the reconstruction of planar curves (1manifolds) out of noisy point samples of a sel-fintersecting or nearly sel-fintersecting planar curve C -- C:[a,b]⊂R→R 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 sel fintersect -- Existing algorithms for curve reconstruction out of either noisy point samples or pixel data, do not produce a (possibly disconnected) Piecewise Linear 1manifold approaching the whole point sample -- The algorithm implemented in this work uses Principal Component Analysis (PCA) with elliptic support regions near the selfintersections -- 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 noncorrelation at the self-intersections(nonmanifold neighborhoods) but also to occasional high noise at the nonselfintersecting (1manifold) neighborhoodsÍtem Funciones(Universidad EAFIT, 2015) Esteban Duarte, Pedro Vicente; Esteban Duarte, Pedro Vicente. Universidad EAFIT, Escuela de Ciencias, Ciencias Básicas, Medellín, Colombia; Proyecto 50El concepto de función es tal vez el más importan en el Cálculo -- A partir de él, se definen el límite, la continuidad, la derivada, la integral de funciones, etc. -- Además, las funciones describen modelos en muchas ramas de la ciencia, como la Física, la Economía, la Biología, entre otras -- El estudio de las funciones, sus propiedades, gráficas e interpretaciones, acordes con el contexto, permiten describir un sin número de aplicaciones y solucionar una gran variedad de problemas de diversos tiposÍtem Limits of quotients of polynomial functions in three variables(ASSOC COMPUTING MACHINERY, 2017-06-01) Velez, Juan D.; Hernandez, Juan P.; Cadavid, Carlos A.; Velez, Juan D.; Hernandez, Juan P.; Cadavid, Carlos A.; Universidad EAFIT. Departamento de Ciencias; Matemáticas y AplicacionesA method for computing limits of quotients of real analytic functions in two variables was developed in [4]. In this article we generalize the results obtained in that paper to the case of quotients q = f(x, y, z)/g(x, y, z) of polynomial functions in three variables with rational coefficients. The main idea consists in examining the behavior of the function q along certain real variety X(q) (the discriminant variety associated to q). The original problem is then solved by reducing to the case of functions of two variables. The inductive step is provided by the key fact that any algebraic curve is birationally equivalent to a plane curve. Our main result is summarized in Theorem 2. In Section 4 we describe an effective method for computing such limits. We provide a high level description of an algorithm that generalizes the one developed in [4], now available in Maple as the limit/multi command.Ítem Operaciones con intervalos y puntos en el plano(Universidad EAFIT, 2015) Esteban Duarte, Pedro Vicente; Esteban Duarte, Pedro Vicente. Universidad EAFIT, Escuela de Ciencias, Ciencias Básicas, Medellín, Colombia; Proyecto 50Los intervalos son conjuntos de números reales que se pueden representar gráficamente sobre la recta real -- Se pueden trabajar con las reglas de los conjuntos en general, como son el complemento, la intersección, la unión, la diferencia y la diferencia simétrica -- La comprensión de los intervalos permite el trabajo con el dominio y el rango de relaciones y funciones -- Para tener un manejo adecuado del trabajo con intervalos, es necesario graficarlos en la recta real y escribirlos en la notación de conjuntos a partir de desigualdades -- De otro lado, la ubicación de puntos en el plano y sombreado de regiones en el mismo son aspectos que se deben de tener en cuenta cuando se trabaja con desigualdadesÍtem Propuesta de diseño de una oficina de gestión de proyectos (PMO) para Industrias Tomy S.A.S(Universidad EAFIT, 2021) Gutiérrez Angulo, Julián Andrés; Tobar Guinand, José MauricioÍtem Reduction of speckle noise in digital holography(SPIE-INT SOC OPTICAL ENGINEERING, 2004-01-01) Garcia-Sucerquia, J.; Ramirez, J.A.H.; Castaneda, R.; Prieto, D.V.; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica AplicadaA fundamental problem in holography, as well optical as digital, is the presence of speckle noise in the reconstruction process. Many approaches have been carried out in order overcome such a problem, ranging from altering the spatial coherence (optical techniques) of the illumination to imaging processing techniques (digital techniques). This work shows the merged use of digital imaging techniques in order to reduce the speckle noise in digital reconstruction of optically recorded Fresnel's holograms. The proposed filtering techniques are illustrated with experimental results.