Examinando por Materia "Mathematical models"
Mostrando 1 - 20 de 70
Resultados por página
Opciones de ordenación
Ítem Análisis de esfuerzos hertzianos de elementos de máquinas en Matlab(Universidad EAFIT, 2005) Castro Guzmán, Jairo Mauricio; Restrepo Ochoa, Jorge LuisÍtem Análisis de la calidad de la imagen sísmica en atributos 3D, al aplicar una nueva definición de Binning en la migración Kirchhoff pre-apilado(Universidad EAFIT, 2011) Martínez Corredor, Robiel; González Álvaréz, HerlingÍtem Análisis de sensibilidad a un modelo de transporte de sedimentos: Golfo de Urabá, Colombia(Universidad EAFIT, 2011) Velásquez Montoya, Liliana; Escobar Sierra, Carlos AlejandroÍtem Análisis del acondicionamiento para un sistema de ecuaciones generado a partir de la ecuación de Freudenstein(Universidad EAFIT, 2015) Guerrero García, José Alberto; Estrada Álvarez, John JairoEn este proyecto se estudian algunos de los problemas numéricos que surgen al usar la ecuación de Freudenstein en el análisis de mecanismos y estudiar experimentalmente el sistema de ecuaciones que se plantean al construir una falange proximal de un dedo antropomórfico, cuyo funcionamiento sea similar al de un homólogo humano desarrollado previamente por la referencia [1] (Édgar Alfredo Portilla Flores, Junio de 2010), esto conllevo a identificar si el sistema obtenido que modela la falange proximal, pueda ser inconsistente o mal condicionado usando el algoritmo de SOR -- Con lo anterior, estudiamos de una manera Heurística el sistema para ver si es posible mejorarlo en convergencia y precisión -- En la primera parte se describe el planteamiento del problema para mostrar el uso de la ecuación de Freudenstein, posteriormente el sistema de ecuaciones obtenidas se usará con el propósito de implementar un algoritmo de aproximación a la solución numérica basadas en el método de SOR -- El trabajo se llevó a cabo utilizando la herramienta de simulación Simulink de Matlab, la cual permite investigar el comportamiento del sistema en aspectos de condicionamiento, convergencia y precisión -- Esto abre múltiples posibilidades de simular, sin incurrir en costos elevados y en problemas asociados en la construcción de un modelo físico en laboratorio -- En el trabajo no se realiza un nuevo modelo físico del dedo falange proximal, pero si debía darse como referente los resultados numéricos ya establecidos por otros autores [1] (Édgar Alfredo Portilla Flores, Junio de 2010) para verificar los valores numéricos obtenidos que implementasen el algoritmo de SORÍtem Análisis vibracional de motovibradores(Universidad EAFIT, 2006) Restrepo Echeverri, Alejandro; Castañeda Heredia, Leonel FranciscoÍtem 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 Approximated analytical solution to an Ebola optimal control problem(Board Members, 2016-01-01) Hincapié-Palacio, D.; Ospina, J.; Torres, D.F.M.; Hincapié-Palacio, D.; Ospina, J.; Torres, D.F.M.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónAn analytical expression for the optimal control of an Ebola problem is obtained. The analytical solution is found as a first-order approximation to the Pontryagin Maximum Principle via the Euler-Lagrange equation. An implementation of the method is given using the computer algebra system Maple. Our analytical solutions confirm the results recently reported in the literature using numerical methods.Ítem Aproximación al modelo del mercado de telecomunicaciones móviles en Colombia desde la perspectiva de control(Universidad EAFIT, 2013) Sepúlveda Botero, Bertha Bibiana; Quintero Montoya, Olga LucíaEn este trabajo de tesis, se presenta una aproximación a la modelacion del mercado de las telecomunicaciones móviles en Colombia, donde se adolece de este tipo de enfoque, dado que las grandes empresas que tienen el control del mercado no lo hacen publico por los grandes conflictos de tipo economicos que se manejan -- Al inicio del trabajo se hace una breve presentacion del escenario en el que se desarrolla el mercado, la evolucion que ha tenido y algunas consideraciones de competencia, en un mercado que desde sus inicios ha tenido el concurso de muy pocas empresas y ha sido marcado por un gran monopolio -- Para la modelaci on, se parte de datos de usuarios y precios disponibles en las paginas web de los operadores de Telecomunicaciones y de informacion publica disponible en las paginas oficiales del Ministerio de Comunicaciones de Colombia, el modelo de mercado presentado esta compuesto por cuatro empresas de Telecomunicaciones Moviles: Claro (antes Comcel), Movistar, Tigo y UFF; los tres primeros Operadores de Redes M oviles y el cuarto Operador M ovil Virtual -- A la fecha de entrega de la tesis ya han aparecido otros dos operadores m oviles virtualesÍtem Aproximación del uso de redes neuronales en mantenimiento(Universidad EAFIT, 2013) Orozco Álvarez, David; Mora Gutiérrez, Luis AlbertoÍtem Bifurcaciones del modelo Lotka-Volterra difusivo(Universidad EAFIT, 2017) Trujillo Díaz, Leonardo Fabio; Montealegre Cárdenas, MauroÍtem Cálculo del valor presente de rentas vitalicias y temporales de una y hasta cuatro vidas para el sistema pensional colombiano(Universidad EAFIT, 2015) Muñoz Castiblanco, Renán Antonio; Huertas Campos, Jaime AbelÍtem Caracterización de los componentes de suspensión de los vehículos de pasajeros del metro de Medellín(Universidad EAFIT, 2006) Palacio Jaramillo, Marcelo; Pineda Botero, Fabio AntonioÍtem Combined beach - inner shelf erosion in short and medium term (Maspalomas, Canary Islands)(Faculty of Geology, Martí i Franquès, 2012-12-01) Fontán, A; Alcántara-Carrió, J; Correa-Arango, Ivan D.; Universidad EAFIT. Departamento de Geología; Ivan D. Correa-Arango (icorrea@eafit.edu.co); Ciencias del MarThe analysis of the accurate topo-bathymetric digital elevation model (DEM), the cartography of the submarine sedimentary cover and the monitoring of short (seasonal) and medium-term (2000-2009) morphological changes have permitted depicting the erosional trend in the short and medium-term of the Maspalomas sedimentary system. Short-term analysis showed intense sedimentary fluxes between the beaches and the inner shelf, and sedimentary exchanges with other sectors of the inner shelf, while the steep slope inner shelf fronting La Bajeta cape was identified as a sink area. In the medium-term the sediment budget showed high erosion of the supratidal and intertidal sectors of the beaches due to storm waves in the 2005-2006 winter, followed by accretion over the next four years, but which did not reach the initial sedimentary state. The inner shelf and subtidal sector of the beaches showed negative budgets in the short and medium-term. Interannual variability of the wave and wind regimes determines decadal beach erosion-accretion cycles, while long-term climatic change, evidenced at the study area by a decrease of trade winds and NE wave intensity in 2005, is expected to produce a possible increase of erosion at the El Inglés inner shelf and consequently a decrease in sediment inputs to the El Inglés beach and Maspalomas dune field. Finally, the influence of the geological heritage is depicted by the Fataga gully’s control of the present coastal morphology, and by the island relief control of the wind, waves and current directions in the study area.Ítem Combining fuzzy, PID and regulation control for an autonomous mini-helicopter(ELSEVIER SCIENCE INC, 2007-05-15) Sanchez, Edgar N.; Becerra, Hector M.; Velez, Carlos M.; Universidad EAFIT. Escuela de Ciencias; Modelado MatemáticoThis paper reports on the synthesis of different flight controllers for an X-Cell mini-helicopter. They are developed on the basis of the most realistic mathematical model currently available. Two hybrid intelligent control systems, combining computational intelligence methodologies with other control techniques, are investigated. For both systems, Mamdani-type fuzzy controllers determine the set points for altitude/attitude control. These fuzzy controllers are designed using a simple rule base. The first scheme consists of conventional SISO PID controllers for z-position and roll, pitch and yaw angles. In the second scheme, two of the previous PID controllers are used for roll and pitch, and a linear regulator is added to control altitude and yaw angle. These control schemes mimic the action of an expert pilot. The designed controllers are tested via simulations. It is shown that the designed controllers exhibit good performance for hover flight and control positioning at slow speed. © 2006 Elsevier Inc. All rights reserved.Ítem Computational Study of Cell Mobility and Transport Phenomena Through Textile Vascular Grafts Using a Multi-Scale Approach(Universidad EAFIT, 2015) Valencia Cardona, Raúl Adolfo; García Ruíz, Manuel Julio; Bustamante Osorno, JohnTextile vascular grafts are biomedical devices that serve as partial replacement of damaged arterial vessels, prevent aneurysms rupture and restore normal blood flow -- It is believed that the success of a textile vascular graft, in the healing process after implantation, is due to the porous micro-structure of the wall -- Among the key properties that take part in the tissue repair process are the type of fabric and degree of porosity and permeability, defining the ability of a well-controlled environment for the neovascularization, nutrient supply, and cellular transport -- Although the transport of fluids through textiles is of great technical interest in biomedical applications, little is known about predicting the micro-flow pattern and the transport and deposition of individual platelets, related with the graft occlusion -- Often, this information is difficult to obtain experimentally both in vivo and in vitro, representing a great deal of research efforts -- The aim of this work is to investigate how the type of fabric, permeability and porosity affect both the local fluid dynamics at several scales and the fluid-particle interaction among platelets in textile grafts with an anastomosis of end-to-end configuration -- Two types of samples were analyzed: woven and electrospun, this last one has been manufactured -- This study involves both experimental and computational tests -- The experimental tests were performed to characterize the permeability and porosity under static conditions -- The computational tests are based on a multiscale approach where the fluid flow was solved with the Finite Element Method and the discrete particles were solved with the Molecular Dynamic Method -- The fluid-particle interaction was accomplished in one-, two-, and four-ways, where the blood was considered as a suspension of platelets in plasma -- The textile wall was considered as a porous media with two scales of length: straight tubular structure with porous walls for the macro-domain and representative unit cells of fabric for the micro-domain. Additionally, it presents the implementation of a numerical case that includes one of the main applications of textile vascular grafts to repair Abdominal Aortic Aneurysms (AAA) -- The results have shown that the type of fabric in textile vascular grafts and the degree of porosity and permeability affect the local fluid dynamics and the level of penetration of platelet particles through the graft wall at several length scales, thus indicating their importance as design parameters -- It was found that the permeability is strongly depends on the micro-structure of the fabric, changing the local fluid dynamics and the time of residence of platelets inside the wall -- Moreover, the porous walls cause deviations from Poiseuille flow due to leakage flow through the wall from a macroscopic viewpoint -- Lastly, it was possible to observe that the textile wall with different porosities, acting like a barrier between the blood and an aneurysmal zone, affects the flow pattern, the number of platelets adhered to the artificial surface and the time of residence of platelets into the aneurysmal zone -- In conclusion, predicting the flow pattern and the mobility of blood cells through the textile wall before the graft is manufactured, the development of new textile grafts can be improvedÍtem Control and parameter estimation of a mini-helicopter robot using rapid prototyping tools(World Scientific and Engineering Academy and Society (WSEAS) Press, 2006-01-01) Vélez S., C.M.; Agudelo, A.; Universidad EAFIT. Escuela de Ciencias; Modelado MatemáticoThis paper shows the control and parameter estimation of a mini-helicopter robot using a rapid prototyping environment based on Matlab/Simulink. The parameter estimation task is facilitated by the availability of a block-based visual simulation model and its integration in a general Matlab environment, with the feasibility of use of many other tools. The environment is integrated by modules which use common Matlab tools (ground control station, linearization, parameter estimation, heuristic identification) and own modules developed specifically for simulation, state estimation and multirate control. An example is presented in a software-in-the-loop context, showing all possibilities of the software environment including supervisory, estimation, linearization, and control tasks.Ítem Declarative debugging of functional logic programs(Elsevier BV, 2001-01-01) Alpuente, M.; Correa, F.J.; Falaschi, M.; Alpuente, M.; Correa, F.J.; Falaschi, M.; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónWe present a general framework for the declarative debugging of functional logic programs, which is valid both for eager as well as lazy programs. We associate to our programs a semantics based on a (continuous) immediate consequence operator which models computed answers. Then we show that, given the intended specification of a program P, it is possible to check the correctness of P by a single step of the immediate consequence operator. We also present a more effective methodology which is based on abstract interpretation. By approximating the intended specification of the success set we derive a finitely terminating debugging method, which can be used statically. Our framework is parametric w.r.t. to the chosen approximation of the success set. We present one specific example of approximation. We provide an implementation of our debugging system which shows experimentally on a wide set of benchmarks that we are able to find some common errors in the user programs. © 2001 Published by Elsevier Science B. V.Ítem Desarrollo de un dispositivo cilindro-émbolo para la medición de algunas propiedades y procesos termodinámicos clásicos con carácter académico(Universidad EAFIT, 2011) Mira Hernández, Carolina; París Londoño, Luis SantiagoÍtem Desarrollo de un modelo predictivo computacional para el diagnóstico de la condición de bombas centrífugas(Universidad EAFIT, 2005) Botero Herrrera, Francisco Javier; Castañeda Heredia, Leonel FranciscoÍtem Design of computer experiments applied to modeling compliant mechanisms(DELFT UNIV TECHNOLOGY, FAC INDUST DESIGN ENG, 2010-01-01) Arango, D.R.; Acosta, D.A.; Durango, S.; Ruiz, O.E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis article discusses a procedure for force-displacement modeling compliant mechanisms by using a design of computer experiments methodology. This approach produces a force-displacement metamodel that is suited for real-time control of compliant mechanisms. The term metamodel is used to represent a simplified and efficient mathematical model of unknown phenomenon or computer codes. The metamodeling of compliant mechanisms is performed from virtual experiments based on factorial and space filling design of experiments. The procedure is used to modeling the quasi-static behavior of the HexFlex compliant mechanism. The HexFlex is a parallel compliant mechanism for nanomanipulating that allows six degrees of freedom of its moving stage. The metamodel of the HexFlex is performed from virtual experiments by the Finite Element Method (FEM). The obtained metamodel for the HexFlex is linear for the movement range of the mechanism. Simulations of the metamodel were conducted, finding good accuracy with respect to the virtual experiments. © Organizing Committee of TMCE 2010 Symposium.