Sistemas y Telemática Vol.10 No. 21
URI permanente para esta colecciónhttp://hdl.handle.net/10906/66287
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Ítem Técnica de Búsqueda para la Prestación de Servicios, basada en Sistemas Multi-Agente y Redes P2P(Universidad Icesi, 2012-04-01) Muñoz Andrade, Alejandro; Muñoz Luna, Diego Eryk; Mage, Pablo AugustoThe ability to find services in unstructured P2P networks; it has become a difficult task execution by the topology of the network, and the instability of the various servers that are not always available for service. It aims to develop a search technique supported on Multi-agent Systems to establish the behavior of these super-nodes, the main disadvantage of these multiagent systems is communication between agents in a P2P environment, to solve this limitation is to be used the protocols of the JXTA technology as a mediator and facilitator in communications multi-agent system, this technique would give us the possibility to reach different servers within the P2P network and incorporate these nodes behavior by agents in the system.Ítem Calibración Basada en Medidas para Modelos de Trazado de Rayos en 3D para Ambientes Exteriores Urbanos andinos(Universidad Icesi, 2012-04-01) Guevara Ibarra, Dinael; Navarro Cadavid, Andrés; Africano, María VictoriaDue to the complexity of a real situation, estimation of path loss using the ray-tracing method usually assumes one or three large classes of homogeneous materials to represent the building walls, building roofs and street floors in order to have a viable model of the 3D environment. However, in a real case, an outdoor environment consists of many buildings and streets made of heterogeneous materials. Additionally, the characterizations of these classes of materials are usually taken from research of other authors with specific materials on site and often not done for the frequency band of operation. We analyze the behavior of the statistical variation of standard deviation, correlation coefficient and the average error between the values of estimated and measured path loss data when considering various values of permittivity of these three classes. Finally, we adjust the values of permittivity, obtaining a reasonable improvement of ray tracing to estimate the path-lossÍtem Aplicación de inteligencia artificial para el diseño sostenible de vanos en el trópico(Universidad Icesi, 2012-04-01) Betancourt Velasco, María Clara; García Alvarado, Rodrigo; Quintero Villareal, Lina MarcelaThe envelope openings of houses have a strong implication in the indoor environmental quality and energy consumption. Nevertheless, there are no precise regulations for its design in equatorial tropics. Normally these designs are based in the previous experiences and common sense of the architect. Determining the correct configuration of a design problem with the desired performance is now possible with the introduction of Parametric Design and Genetic Algorithms; through these it’s possible to obtain the best alternatives in the initial phase of design. The main focus of this investigation is to design windows that proportion adequate conditions of thermal and visual comfort, for a warm and humid tropical climate. The use of generative tools allows the evaluation of results in the initial stages of the project, giving the designer the possibility of choosing among diverse results with a high grade of efficiency and sustainability.Ítem Modelo de estimación diferencial de la propagación térmica en 3D mediante diferencias finitas(Universidad Icesi, 2012-04-01) Loaiza Correa, Humberto; Restrepo Girón, Andrés DavidIn this paper, a new mathematical model based on finite difference discretization of the Fourier’s 3D heat propagation model, is shown. From this one, a new technique is proposed to detect flaws in composite thin layers, under evaluation by a Pulsed Active Thermography experiment. The discrete model defined is easily adaptable to a spatial filter structure, which can be applied to the infrared sequence of images acquired from that thermography experiment, to obtain a better contrast between possible internal flaws and sound regions of material. The performance of the technique proposed is evaluated using artificial thermal sequences generated by ThermoCalc6L, software that is able to compute dynamic thermal distributions in anisotropic layered solids, simulating defects and different excitation sets. Results show that this technique offers a better contrast between defect and background thermal information, than other common technique like Differential Absolute Contrast (DAC), and it runs faster than the classic 3D thermal filtering method. Palabras clave Termografía activa; termografía pulsada; propagación térmica; contraste térmico; filtro espacial. Keywords Active thermography; pulsed thermography; thermal propagation; thermal contrast; spatial filter. 1 Fecha de recepción: Abril 13 de 2012 Fecha de aceptación: Mayo 14 de 2012 Andrés David Restrepo Girón, MSc adareg378@gmail.com Grupo de Investigación en Instrumentación Electrónica (GIE) Universidad Santiago de Cali, Colombia Humberto Loaiza Correa, PhD humberto.loaiza@correounivalle.edu.co Grupo de Investigación en Percepción y Sistemas inteligentes (PSI) Universidad del Valle, Colombia Citación: Restrepo, A. & Loaiza, H.(2012). Modelo de estimación diferencial de la propagación térmica en 3D mediante diferencias finitas. Revista S&T, 10(21), 9-26 Modelo de estimación diferencial de la propagación térmica en 3D mediante diferencias finitas A model for differential estimation of 3D thermal