http://hdl.handle.net/2117/1580 2013-06-19T15:50:12Z http://hdl.handle.net/2117/14463 Title: MEET: Motif Elements Estimation Toolki Authors: Pairó Castiñeira, Erola; Maynou Fernández, Joan; Vallverdú Ferrer, Montserrat; Gallardo Chacón, Joan Josep; Caminal Magrans, Pere; Marco Colás, Santiago; Perera Lluna, Alexandre Abstract: MEET (Motif Elements Estimation Toolkit) es un paquete en R que integra un conjunto de algoritmos para la detección computacional de los puntos de unión de los factores de transcripción (TFBS). El paquete en R MEET incluye cinco programas de búsqueda de motivos: MEME/MAST (Multiple Expectation-Maximization for Motif Elicitation), Q-residuals, MDscan (Motif Discovery scan), ITEME (Information Theory Elements for Motif Estimation) y Match. Además, permite al usuario trabajar con diferentes algoritmos de alineamiento múltiple: MUSCLE (Multiple Sequence Comparison by Log-Expectation), ClustalW y MEME. El paquete puede trabajar en dos modos diferentes, entrenamiento y detección. El modo entrenamiento permite escoger los parámetros óptimos del detector escogido. Y el modo detección permite, una vez escogidos los parámetros, analizar un genoma en busca de puntos de unión. Además, ambos modos pueden combinar los diferentes métodos de alineamiento y de detección, permitiendo al usuario un amplio abanico de posibilidades. Esta característica permite comparar los diferentes métodos computacionales al mismo nivel,sin realizar ningún agravio comparativo debido al alineamiento. http://hdl.handle.net/2117/19513 Title: Simplified Voronoi diagrams for motion planning of quadratically-solvable Gough-Stewart platforms Authors: Vaca Alzate, Rubén Hernando; Aranda López, Juan; Thomas, Federico Abstract: The obstacles in Configuration Space of quadratically-solvable Gough-Stewart platforms, due to both kinematic singularities and collisions, can be uniformly represented by a Boolean combination of signs of 4×4 determinants involving the homogeneous coordinates of sets of four points. This Boolean combination induces a measure of distance to obstacles in Configuration Space from which a simplified Voronoi diagram can be derived. Contrary to what happens with standard Voronoi diagrams, this diagram is no longer a strong deformation retract of free space but, as Canny proved in 1987, it is still complete for motion planning. Its main advantage is that it has lower algebraic complexity than standard Voronoi diagrams based on the Euclidean metric. 2013-06-05T08:29:02Z http://hdl.handle.net/2117/19499 Title: Aprendizaje cooperativo aplicado a la docencia de las asignaturas de programación en ingeniería informática Authors: Ferrer Sumsi, Miquel; Benavente, Robert; Valveny, Ernest; Garcia-Barnés, Jaume; Lapedriza, A.; Sànchez, Gemma Abstract: En este trabajo se presentan los resultados de la aplicación de la metodología del aprendizaje cooperativo a la docencia de dos asignaturas de programación en ingeniería informática. ‘Algoritmos y programación’ y ‘Lenguajes de programación’ son dos asignaturas complementarias que se organizan entorno a un proyecto común que engloba los contenidos de ambas asignaturas. En la docencia de una parte muy importante de estas asignaturas, la metodología del aprendizaje cooperativo se ha adaptado a sus características específicas. Como muestra de esta adaptación presentamos dos ejemplos de las actividades desarrolladas dentro de la docencia de estas asignaturas. Después de tres años de aplicación, el análisis a nivel cualitativo y cuantitativo de los resultados muestra que éstos son muy satisfactorios y que la aplicación del método cooperativo ha mejorado de forma considerable el rendimiento de los alumnos en ambas asignaturas. 2013-06-04T12:44:34Z http://hdl.handle.net/2117/19477 Title: Application of graph embedding to solve graph matching problems Authors: Valveny, Ernest; Ferrer Sumsi, Miquel Abstract: Graphs have very interesting properties for object representation in pattern recognition. However, graph matching algorithms are usually computationally complex. In addition, graphs are harder to manipulate and operate than feature vectors. In the last years, some attempts have been made to combine the best of the graph and the vector domains in order to get the advantages of both worlds. In this paper we review some of these works on graph kernels and graph embedding and we show how graph embedding can be used to obtain accurate and efficient approximations of the median graph. The median graph can be seen as the representative of a set of graphs but its application has been very limited up to now due to computational reasons. With this new approach, we can obtain an approximate median graph using real databases containing large graphs. Mots-clés : Graph Matching, Graph Embedding, Graph Kernels, Vector Spaces, Median Graph tors. Secondly, the repository of algorithmic tools based on graphs is quite limited when compared to the tools available for patterns represented using feature vectors. This is mainly due to the fact that vectors are simple structures with good mathematical properties that can be readily manipulated algebraically. For this reason, new trends in structural pattern recognition have been proposed merging both worlds in order to extend the available statistical tools to the graph domain [BUN 05]. In this way, graph kernels permit to compute the dot product of the representation of a pair of graphs in a vector space without having to define the explicit transformation between the graphs and the vector space. As a consequence all classification algorithms based on the computation of a dot product, such as Support Vector Machines (SVM) become immediately available for graphs. On the other hand, graph embedding aims to find an explicit transformation between graphs and a vector space. In this way, we can give a semantic interpretation to this transformation. In addition we can also manipulate the vectors resulting from this transformation with all the mathematical machinery that can be applied to vectors. We are not restricted to the dot product. In this paper, we firstly review the main techniques used to define graph kernels and graph embedding in sections 2 and 3, respectively. Then, in section 4 we show the application of graph embedding to a particular complex graph matching problem : the computation of the median graph. In this section we introduce the concept of median graph as a representative of a set of graphs and then, we describe how it can be efficiently computed using graph embedding. We also show some results of its application to real pattern recognition problems. Finally, in section 5 we state some conclusions and point out some challenges for the future. 2013-05-31T13:13:23Z http://hdl.handle.net/2117/19469 Title: Ethanol catalytic membrane reformer for direct PEM FC feeding Authors: Koch, Reinhold; López, Eduardo; Jiménez Divins, Nuria; Allué Fantova, Miguel; Jossen, Andreas; Riera Colomer, Jordi; Llorca Piqué, Jordi Abstract: In this paper an ethanol reformer based on catalytic steam reforming with a catalytic honeycomb loaded with RhPd/CeO2 and palladium separation membranes with an area of 30.4 cm2 has been used to generate a pure hydrogen stream of up to 100 ml/min to feed a PEM fuel cell with an active area of 5 cm2. The fuel reformer behavior has been extensively studied under different temperature, ethanol–water flow rate and gas pressure at a fixed S/C ratio of 1.6 (molar). The hydrogen yield has been controlled by acting upon the ethanol–water fuel flow and gas pressure. A mathematical model of the ethanol reformer has been developed and an adaptive and predictive control has been implemented on a real time system to take account of its nonlinear behavior. With this control the response time of the reformer can be reduced by a factor of 7 down to 8 s. The improved dynamics of the controlled reformer match better the quickly changing hydrogen demands of fuel cells. They reached a magnitude where costly hydrogen buffers between the reformer and the fuel cell can be omitted and an electric buffer at the output of the fuel cell is sufficient. 2013-05-31T09:26:20Z http://hdl.handle.net/2117/19458 Title: Performance improvement by temperature control of an open-cathode PEM fuel cell system Authors: Strahl, Stephan; Perrier, Michel; Husar, Attila Peter; Riera Colomer, Jordi; Serra, Maria Abstract: The work presented in this article combines experimental analysis and theoretical studies of temperature effects on the performance of an open-cathode, self-humidified PEM fuel cell system for the design of optimization strategies. The experimental analysis shows the great potential of improving the system performance by proper temperature management. The most significant temperature dependent parameters of the system under study are the activation polarization and the water content of the ionomer of the catalyst layer. An Extremum seeking control algorithm is proposed to regulate the temperature to a voltage maximum. However, the slow dynamics of the temperature related catalyst-drying effect on performance complicate the optimal thermal management via model-free control strategies. 2013-05-30T12:46:54Z http://hdl.handle.net/2117/19444 Title: Methodology for determine the moment of disconnection of patients of the mechanical ventilation using discrete wavelet transform Authors: González, H.; Acevedo, H.; Arizmendi Pereira, Carlos Julio; Giraldo Giraldo, Beatriz Abstract: The process of weaning from mechanical ventilation is one of the challenges in intensive care units. 66 patients under extubation process (T-tube test) were studied: 33 patients with successful trials and 33 patients who failed to maintain spontaneous breathing and were reconnected. Each patient was characterized using 7 time series from respiratory signals, and for each serie was evaluated the discrete wavelet transform. It trains a neural network for discriminating between patients from the two groups. 2013-05-29T09:38:55Z http://hdl.handle.net/2117/19415 Title: Design of a 3-DoF joint system with dynamic servo-adaptation in orthotic applications Authors: Amigo, Luis; Casals Gelpi, Alicia; Amat Girbau, Josep Abstract: Most exoskeleton designs rely on structures and mechanical joints that do not guarantee the right match between the orthosis and the user. This paper proposes a virtual joint model based on three active degrees of freedom aimed to emulate a human joint. This joint is capable of performing a dynamic servo-adaptation in real-time to avoid misalignments and to provide a flexible adjustment to different users’ sizes in order to avoid undesirable interaction forces. 2013-05-27T14:47:25Z http://hdl.handle.net/2117/19414 Title: Diseño de una arquitectura de ortesis adaptativa y estudio de la personalización de su grado de asistencia Authors: Amigo, Luis; Giralt Ludevid, Xavier; Fernández, Quim; Casals Gelpi, Alicia; Amat Girbau, Josep Abstract: Uno de los principales objetivos de las terapias de rehabilitación del miembro superior asistidas por robots es incrementar la recuperación funcional al finalizar la terapia y a su vez disminuir el tiempo de esta recuperación, promoviendo la neuroplasticidad en pacientes con problemas neuromusculares. En este sentido es importante que los exoesqueletos se adapten a los movimientos del paciente y no al revés. Este artículo presenta un ortesis para la extremidad superior con servoadaptación dinámica para la articulación del codo con el objetivo de reducir las fuerzas de interacción causadas por el desalineamiento entre el robot y la extremidad superior. Se estudia además el grado de asistencia que se debe efectuar durante la terapia con el objetivo de promover la neuroplasticidad y que el paciente trabaje en la totalidad de sus capacidades optimizando así la recuperación. 2013-05-27T14:28:48Z http://hdl.handle.net/2117/19412 Title: Sistema integrado de posicionado, visualización y acotamiento de áreas de trabajo en cirugía ortopédica Authors: Casals Gelpi, Alicia; Basomba Feliu, Joan; Bergès, Eduard; Frigola Bourlon, Manel; Amat Girbau, Josep Abstract: La percepción que el cirujano tiene de la intervención que está realizando es esencial para garantizar una operación segura y eficiente. En cirugía robotizada los sistemas de percepción disponibles son muy limitados, lo que puede paliarse generando información visual a proyectar sobre el paciente. El trabajo describe el modo de generar y proyectar la imagen 3D obtenida por TAC, así como trayectorias previamente planificadas, que serán de ayuda al guiado. Esta información es también utilizada para el guiado del robot que trabaja en cooperación con el cirujano, en modo comanipulación, evitando situaciones de riesgo y ayudando al cirujano en el guiado de los instrumentos quirúrgicos. 2013-05-27T13:52:06Z http://hdl.handle.net/2117/19405 Title: Study of patient-orthosis interaction forces in rehabilitation therapies Authors: Amigo, Luis; Fernández, Quim; Giralt Ludevid, Xavier; Casals Gelpi, Alicia; Amat Girbau, Josep Abstract: The design of mechanical joints that kinematically behave as their biological counterparts is a challenge that if not addressed properly can cause inadequate forces transmission between robot and patient. This paper studies the interaction forces in rehabilitation therapies of the elbow joint. To measure the effect of orthosis-patient misalignments, a force sensor with a novel distributed architecture has been designed and used for this study. A test-bed based on an industrial robot acting as a virtual exoskeleton that emulates the action of a therapist has been developed and the interaction forces analyzed. 2013-05-27T10:52:03Z http://hdl.handle.net/2117/19403 Title: Detection of movements with attention or distraction to the motor task during robot-assisted passive movements of the upper limb Authors: Antelis, Javier M.; Montesano, Luis; Giralt Ludevid, Xavier; Casals Gelpi, Alicia; Minguez, Javier Abstract: Robot-assisted rehabilitation therapies usually focus on physical aspects rather than on cognitive factors. However, cognitive aspects such as attention, motivation, and engagement play a critical role in motor learning and thus influence the long-term success of rehabilitation programs. This paper studies motor-related EEG activity during the execution of robot-assisted passive movements of the upper limb, while participants either: i) focused attention exclusively on the task; or ii) simultaneously performed another task. Six healthy subjects participated in the study and results showed lower desynchronization during passive movements with another task simultaneously being carried out (compared to passive movements with exclusive attention on the task). In addition, it was proved the feasibility to distinguish between the two conditions. 2013-05-27T10:27:19Z http://hdl.handle.net/2117/19376 Title: BoVDW: Bag-of-Visual-and-Depth-Words for gesture recognition Authors: Hernandez Vela, Antonio; Bautista, Miguel Angel; Perez-Sala, Xavier; Ponce, Víctor; Baró, Xavier; Pujol, Oriol; Angulo Bahón, Cecilio; Escalera, Sergio Abstract: We present a Bag-of-Visual-and-Depth-Words (BoVDW) model for gesture recognition, an extension of the Bag-of-Visual-Words (BoVW) model, that benefits from the multimodal fusion of visual and depth features. State-of-the-art RGB and depth features, including a new proposed depth descriptor, are analysed and combined in a late fusion fashion. The method is integrated in a continuous gesture recognition pipeline, where Dynamic Time Warping (DTW) algorithm is used to perform prior segmentation of gestures. Results of the method in public data sets, within our gesture recognition pipeline, show better performance in comparison to a standard BoVW model. 2013-05-23T07:28:50Z http://hdl.handle.net/2117/19373 Title: A MILP model to design hybrid wind-photovoltaic isolated rural electrification projects in developing countries Authors: Ferrer Martí, Laia; Doménech Lega, Bruno; García Villoria, Alberto; Pastor Moreno, Rafael Abstract: Electrification systems based on the use of renewable energy sources are a suitable option for providing electricity to isolated communities autonomously. Wind and hybrid wind–photovoltaic (PV) systems are increasingly getting attention. To electrify scattered communities, designs that combine individual systems and microgrids have recently proven advantageous. In this paper we present a mathematical programming model to optimize the design of hybrid wind–PV systems that solves the location of the wind–PV generators and the design of the microgrids, taking into account the demand of the consumption points and the energy potential. The criterion is the minimization of the initial investment cost required to meet the demand. The proposed hybrid model is tested with realistic size instances and results show the instances are efficiently solved. Moreover, the model is applied to real case studies in Peru; obtained results verify that the hybrid model efficiently finds solutions that significantly reduce cost. http://hdl.handle.net/2117/19366 Title: IT or not to be: the impact of Moodle in the education of developing countries Authors: García Almiñana, Jordi; Somé, Michel; Ayguadé Parra, Eduard; Cabré Garcia, José M.; Casany Guerrero, María José; Frigola Bourlon, Manel; Galanis, Nikolaos; García-Cervigon Gutiérrez, Manuel; Guerrero Zapata, Manel; Muñoz Gracia, María del Pilar Abstract: E-learning environments, such as Moodle, provide a technology that fosters the improvement of the educational system in developed countries, where education is traditionally performed with relatively high standards of quality. A large number of case studies and research have been conducted to demonstrate how e-learning technologies can be applied to improve both training and learning processes. However, these technologies have not been proved efficient when applied to developing countries. The challenges that must be addressed in developing countries, both technological and societal, are much more complex and the possible solution margins are more constrained than those existing in the context where these technologies have been created. In this paper we show how Moodle can be used to improve the quality of education in developing countries and, even more important, how can be used to turn the educational system more sustainable and effective in the long-term. We describe our experience in implementing a programming course in Moodle for the Higher School of Informatics at the Université Polytechnique de Bobo-Dioulasso, in Burkina Faso (West Africa), joining efforts with local professors in designing and implementing the learning system. The case example has been designed having in mind a number of contextual problems: lack of lecturers, excessive teaching hours per lecturer, massive classes, and curricula organization and stability, among others. We finally discuss how the teaching effort is reduced, the students’ knowledge and capacity improves, and the institutional academic model can be guaranteed with the proposal. For this reason, we claim that information technologies in developing countries are a cost-effective way to guarantee the objectives originally defined in the academic curricula and, therefore, deal with the problem of the education. 2013-05-22T07:16:25Z