Comunicaciones y ponencias de congresos DIMI - MIIS Biltzarretako komunikazioak eta txostenak
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Publication Open Access Parallel solution of nonlinear parabolic problems on logically rectangular grids(Springer, 2007) Arrarás Ventura, Andrés; Portero Egea, Laura; Jorge Ulecia, Juan Carlos; Ingeniería Matemática e Informática; Matematika eta Informatika IngeniaritzaThis work deals with the efficient numerical solution of nonlinear transient flow problems posed on two-dimensional porous media of general geometry. We first consider a spatial semidiscretization of such problems by using a cell-centered finite difference scheme on a logically rectangular grid. The resulting nonlinear stiff initial-value problems are then integrated in time by means of a fractional step method, combined with a decomposition of the flow domain into a set of overlapping subdomains and a linearization procedure which involves suitable Taylor expansions. The proposed algorithm reduces the original problem to the solution of several linear systems per time step. Moreover, each one of such systems can be directly decomposed into a set of uncoupled linear subsystems which can be solved in parallel. A numerical example illustrates the unconditionally convergent behaviour of the method in the last section of the paper.Publication Open Access Embedded pairs of fractional step Runge-Kutta methods and improved domain decomposition techniques for parabolic problems(Springer, 2007) Portero Egea, Laura; Jorge Ulecia, Juan Carlos; Ingeniería Matemática e Informática; Matematika eta Informatika IngeniaritzaIn this paper we design and apply new embedded pairs of Frac- tional Step Runge-Kutta methods to the e±cient solution of multidimensional parabolic problems. These time integrators are combined with a suitable split- ting of the elliptic operator subordinated to a decomposition of the spatial domain and a standard spatial discretization. With this technique we ob- tain parallel algorithms which have the main advantages of classical domain decomposition methods and, besides, avoid iterative processes like Schwarz iterations, typical of them. The use of these embedded methods permits a fast variable step time integration process.Publication Open Access A combined fractional step domain decomposition method for the numerical integration of parabolic problems(Springer, 2004) Portero Egea, Laura; Bujanda Cirauqui, Blanca; Jorge Ulecia, Juan Carlos; Ingeniería Matemática e Informática; Matematika eta Informatika IngeniaritzaIn this paper we develop parallel numerical algorithms to solve linear time dependent coefficient parabolic problems. Such methods are obtained by means of two consecutive discretization procedures. Firstly, we realize a time integration of the original problem using a Fractional Step Runge Kutta method which provides a family of elliptic boundary value problems on certain subdomains of the original domain. Next, we discretize those elliptic problems by means of standard techniques. Using this framework, the numerical solution is obtained by solving, at each stage, a set of uncoupled linear systems of low dimension. Comparing these algorithms with the classical domain decomposition methods for parabolic problems, we obtain a reduction of computational cost because of, in this case, no Schwarz iterations are required. We give an unconditional convergence result for the totally discrete scheme and we include two numerical examples that show the behaviour of the proposed method.Publication Open Access Charge transfer in the Rydberg hydrogen atom metal surface interaction: a transition state approach(2007) Salas, José Pablo; Iñarrea, Manuel; Lanchares, Víctor; Palacián Subiela, Jesús Francisco; Pascual, Ana Isabel; Yanguas Sayas, Patricia; Ingeniería Matemática e Informática; Matematika eta Informatika IngeniaritzaWe study the classical dynamics of a hydrogen atom near a metallic surface in the presence of a uniform electric field. By continuation of families of periodic orbits and surfaces of section we show that, due to the electric field, the atom falls into a Stark regime through two pitchfork bifurcations. The charge transfer is studied by using the Dynamical Transition State Theory. Indeed, we obtain analytically the geometrical structures that in phase space regulate the ionisation of the atom and we calculate efficiently the ionisation probability as a function of the electric field strength.Publication Open Access Redes de brainstorming y formación de equipos innovadores apoyado por herramientas Web 2.0(Asociación Interacción Persona-Ordenador, 2009) Ardaiz Villanueva, Óscar; Nicuesa, Xabier; Brene Artázcoz, Óscar; Sanz de Acedo Lizarraga, María Luisa; Sanz de Acedo Baquedano, María Teresa; Ingeniería Matemática e Informática; Matematika eta Informatika Ingeniaritza; Psicología y Pedagogía; Psikologia eta PedagogiaEsta investigación tiene como finalidad ofrecer una nueva forma de realización de la técnica brainstorming apoyada en herramientas informáticas Web2.0 para mejorar los procesos innovadores. Estas herramientas permiten la participación de muchas personas en las sesiones de generación y evaluación de ideas formando redes de brainstorming. También permiten la formación de grupos de desarrollo de innovación en base a la afinidad entre participantes por su creatividad y su interés por la implementación de las ideas. Se describen los fundamentos, los participantes, las herramientas y los hallazgos de un estudio llevado a cabo en un curso universitario utilizando el método de instrucción 'Pensar activamente en entornos creativos, PAEC'. Los resultados confirman que las redes de brainstorming son efectivas y que los participantes están satisfechos con los grupos de proyecto formados y las ideas a desarrollar.Publication Open Access Characterization of radio propagation channel in urban vehicle to infrastructure environments to support WSNs(MDPI, 2016) Granda, Fausto; Azpilicueta Fernández de las Heras, Leyre; Vargas Rosales, César; López Iturri, Peio; Aguirre Gallego, Erik; Astrain Escola, José Javier; Villadangos Alonso, Jesús; Falcone Lanas, Francisco; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Ingeniería Matemática e Informática; Matematika eta Informatika IngeniaritzaVehicular ad hoc Networks (VANETs) enable vehicles to communicate with each other as well as with roadside units (RSUs). Although there is a significant research effort in radio channel modelling focused in vehicle to vehicle (V2V), not much work has been done for vehicle to infrastructure (V2I) using 3D ray-tracing tools. This work evaluates some important parameters of a V2I wireless channel link such as Received Power, Power Delay Profile, Delay Spread and Coherence Bandwidth, in an urban scenario using a deterministic simulation model based on an in-house 3D Ray-Launching algorithm. Analysis using Wireless Sensor Networks (WSNs) at 868MHz, 2.4 and 5.9 GHz are presented. Results show the highly impact that the distance, link frequency, location of RSUs and obstacles in the LoS (Line of Sight) have in V2I channel propagation. These results constitute the start point in the deployment of radio-planning in V2I environments.Publication Open Access An easy to deploy street light control system based on wireless communication and LED technology(MDPI, 2013) Elejoste Larrucea, Pilar; Angulo Martínez, Ignacio; Perallos Ruiz, Asier; Chertudi Ozamiz, Aitor; García Zuazola, Ignacio Julio; Moreno, Asier; Azpilicueta Fernández de las Heras, Leyre; Astrain Escola, José Javier; Falcone Lanas, Francisco; Villadangos Alonso, Jesús; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Ingeniería Matemática e Informática; Matematika eta Informatika IngeniaritzaThis paper presents an intelligent streetlight management system based on LED lamps, designed to facilitate its deployment in existing facilities. The proposed approach, which is based on wireless communication technologies, will minimize the cost of investment of traditional wired systems, which always need civil engineering for burying of cable underground and consequently are more expensive than if the connection of the different nodes is made over the air. The deployed solution will be aware of their surrounding’s environmental conditions, a fact that will be approached for the system intelligence in order to learn, and later, apply dynamic rules. The knowledge of real time illumination needs, in terms of instant use of the street in which it is installed, will also feed our system, with the objective of providing tangible solutions to reduce energy consumption according to the contextual needs, an exact calculation of energy consumption and reliable mechanisms for preventive maintenance of facilities.Publication Open Access Ubiquitous connected train based on train-to-ground and intra-wagon communications capable of providing on trip customized digital services for passengers(MDPI, 2014) Salaberria, Itziar; Perallos Ruiz, Asier; Azpilicueta Fernández de las Heras, Leyre; Falcone Lanas, Francisco; Carballedo, Roberto; Angulo Martínez, Ignacio; Elejoste Larrucea, Pilar; Bahillo, Alfonso; Astrain Escola, José Javier; Villadangos Alonso, Jesús; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Ingeniería Matemática e Informática; Matematika eta Informatika IngeniaritzaDuring the last years, the application of different wireless technologies has been explored in order to enable Internet connectivity from vehicles. In addition, the widespread adoption of smartphones by citizens represents a great opportunity to integrate such nomadic devices inside vehicles in order to provide new and personalized on trip services for passengers. In this paper, a proposal of communication architecture to provide the ubiquitous connectivity needed to enhance the smart train concept is presented and preliminarily tested. It combines an intra-wagon communication system based on nomadic devices connected through a Bluetooth Piconet Network with a highly innovative train-to-ground communication system. In order to validate this communication solution, several tests and simulations have been performed and their results are described in this paper.Publication Open Access Adjusting fuzzy automata for string similarity measuring(EUSFLAT, 2001) Astrain Escola, José Javier; Villadangos Alonso, Jesús; González de Mendívil Moreno, José Ramón; Garitagoitia Padrones, José Ramón; Fariña Figueredo, Federico; Ingeniería Matemática e Informática; Matematika eta Informatika Ingeniaritza; Automática y Computación; Automatika eta KonputazioaIn this paper, we introduce a fuzzy automaton for computing the similarity between pairs of strings and a genetic method for adjusting its parameters. The fuzzy automaton models the edit operations needed to transform any string into another one. The selection of appropriate fuzzy operations and fuzzy membership values for the transitions leads to improve the system performance for a particular application.Publication Open Access Analysis of radio wave propagation for ISM 2.4GHz wireless sensor networks in inhomogeneous vegetation environments(2014) Azpilicueta Fernández de las Heras, Leyre; López Iturri, Peio; Aguirre Gallego, Erik; Astrain Escola, José Javier; Villadangos Alonso, Jesús; Falcone Lanas, Francisco; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Ingeniería Matemática e Informática; Matematika eta Informatika IngeniaritzaThe use of wireless networks has been extended in an exponential growing due to the improvement in terms of battery life and low consumption of the devices. However, it is highly important to conduct previous radio propagation analysis when deploying a wireless sensor network. These studies are necessary to perform an estimation of the range coverage, in order to optimize the distance between devices in an actual network deployment. In this work, the radio channel characterization for ISM 2.4GHz Wireless Sensor Networks (WSN) in an inhomogeneous vegetation environment has been analyzed. The impact of topology as well as morphology of the environment is assessed by means of an in-house developed 3D Ray Launching code, to emulate the realistic operation in the framework of the scenario. Experimental results gathered from a measurements campaign conducted by deploying a ZigBee Wireless Sensor Network, are analyzed and compared with simulations in this paper. The scenario where this network is intended to operate is a combination of buildings and diverse vegetation species. To gain insight in the effects of radio propagation, a simplified vegetation model has been developed, considering the material parameters and simplified geometry embedded in the simulation scenario. The use of deterministic tools can aid to know the impact of the topological influence in the deployment of the optimal Wireless Sensor Network in terms of capacity, coverage and energy consumption, making the use of these systems attractive for multiple applications in inhomogeneous vegetation environments.Publication Open Access Google sites en el área de matemáticas(2013) Martínez Gil, ClaudioPresentación de un sitio-web donde se integran las diferentes herramientas que proporciona Google: Google calendar para la planificación temporal de la asignatura, Google grupos como foro de los alumnos, Google drive para compartir con los alumnos los ficheros de la asignatura. Además se insertan actividades creadas con Hotpotatoes y applets creados con Geogebra. También presentaciones creadas por el alumnado.