The Michelson system

Treballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2016, Director: Àlex HaroThe Michelson system is a three dimension autonomous ODE system that arises in the context of studying the travelling waves solutions of the Kuramoto-Sivashinsky equation. Nonetheless, this system has its own relevance in itself, as it possesses some rich dynamics. In particular, the Michelson system is an interesting system to study since it is non-Hamiltonian, volume preserving and has a time reversing symmetry. In this work we will study the main properties of the system from a theoretical and a numerical point of view. More precisely, in the theoretical part we introduce the properties mentioned above and study the equilibrium points stability and their invariant manifolds. Moreover, some results on the existence of some type of orbits are also given. For the numerical part, we implement an algorithm to integrate orbits and give detailed methods to find periodic orbits. However, the main result of this block is the implementation of an algorithm to find the heteroclinic orbits of the Michelson system

On the use of Neural Networks to solve Differential Equations

[EN]Artificial neural networks are parametric models, generally adjusted to solve regression and classification problem. For a long time, a question has laid around regarding the possibility of using these types of models to approximate the solutions of initial and boundary value problems, as a means for numerical integration. Recent improvements in deep-learning have made this approach much attainable, and integration methods based on training (fitting) artificial neural networks have begin to spring, motivated mostly by their mesh-free nature and scalability to high dimensions. In this work, we go all the way from the most basic elements, such as the definition of artificial neural networks and well-posedness of the problems, to solving several linear and quasi-linear PDEs using this approach. Throughout this work we explain general theory concerning artificial neural networks, including topics such as vanishing gradients, non-convex optimization or regularization, and we adapt them to better suite the initial and boundary value problems nature. Some of the original contributions in this work include: an analysis of the vanishing gradient problem with respect to the input derivatives, a custom regularization technique based on the network’s parameters derivatives, and a method to rescale the subgradients of the multi-objective of the loss function used to optimize the network.[ES]Las redes neuronales son modelos paramétricos generalmente usados para resolver problemas de regresiones y clasificación. Durante bastante tiempo ha rondado la pregunta de si es posible usar este tipo de modelos para aproximar soluciones de problemas de valores iniciales y de contorno, como un medio de integración numérica. Los cambios recientes en deep-learning han hecho este enfoque más viable, y métodos basados en entrenar (ajustar) redes neuronales han empezado a surgir motivados por su no necesidad de un mallado y su buena escalabilidad a altas dimensiones. En este trabajo, vamos desde los elementos más básicos, como la definición de una red neuronal o la buena definición de los problemas, hasta ser capaces de resolver diversas EDPs lineales y casi-lineales. A lo largo del trabajo explicamos la teoría general relacionada con redes neuronales, que incluyen tópicos como los problemas de desvanecimiento de gradientes (vanishing gradient), optimización no-convexa y técnicas de regularización, y los adaptamos a la naturaleza de los problemas de valores iniciales y de contorno. Algunas de las contribuciones originales de este trabajo incluyen: un análisis del desvanecimiento de gradientes con respecto a las variables de entrada, una técnica de regularización customizada basada en las derivadas de los parámetros de la red neuronal, y un método para rescalar los subgradientes de la función de coste multi-objectivo usada para optimizar la red neuronal

Intra-household Time Allocation: Gender Differences in Caring for Children

Der vorliegende Beitrag untersucht auf Basis von Daten des Sozio-oekonomischen Panels für Deutschland (SOEP), inwieweit selbständige Ausländer in Deutschland überdurchschnittlich hohe Einkommen erzielen. Die Untersuchung zeigt, dass ausländische Selbständige insgesamt höhere Einkommen erzielen als angestellt tätige Ausländer und dass der Unterschied größer ist als bei Selbständigen deutscher Nationalität. Die Konsequenzen dieser Untersuchungsergebnisse für Wirtschaftspolitikund Gründungslehre werden diskutiert. Die Ergebnisse der Untersuchung zeigen differenzierten Forschungsbedarf im Hinblick auf unterschiedliche Optionen der Entrepreneurship Education. This paper analyses the intra-household allocation of time to show gender differences in childcare. In the framework of a general efficiency approach, hours spent on childcare by each parent are regressed against individual and household characteristics, for five samples (Denmark, France, Germany, Italy and Spain), with data being drawn from the European Community Household Panel-ECHP (1994-2001). Empirical results show a clear inequality in childcare between fathers and mothers, with this being more evident in Mediterranean countries. Panel data estimates reveal that, in general, caring tasks are mainly influenced by the presence of young children in the household, by the total non-labor income, and by the ratio of mothers' non-labor income to family's non-labor income, with this latter variable exhibiting a different behavior across genders and across countries.Childcare, gender differences, intra-household allocation, time use

Intra-Household Time Allocation: Gender Differences in Caring for Children

This paper analyses the intra-household allocation of time to show gender differences in childcare. In the framework of a general efficiency approach, hours spent on childcare by each parent are regressed against individual and household characteristics, for five samples (Denmark, France, Germany, Italy and Spain), with data being drawn from the European Community Household Panel-ECHP (1994-2001). Empirical results show a clear inequality in childcare between fathers and mothers, with this being more evident in Mediterranean countries. Panel data estimates reveal that, in general, caring tasks are mainly influenced by the presence of young children in the household, by the total non-labor income, and by the ratio of mothers' non-labor income to family's non-labor income, with this latter variable exhibiting a different behavior across genders and across countries.childcare, gender differences, intra-household allocation, time use

El Entorno: Vision - E Laboratory

Se presenta un entorno de programación para el estudio y desarrollo de algoritmos de tratamiento de imágenes y visión por computador. La herramienta permite la programación en cualquier lenguaje, con la única restricción de que se desarrolle bajo entornos windows. Se ha concebido como instrumento de ayuda a la realización de prácticas de laboratorio de alumnos en las asignaturas de tratamiento digital de imágenes de ingeniería informática.Junta de Andalucía P09-TIC538

Estado de salud dental y gingival de los pacientes internos con trastornos mentales del Hospital Psiquiátrico “José Dolores Fletes Valle” en el año 2014

Los pacientes con trastornos mentales presentan diversas dificultades para apropiarse de técnicas en higiene oral, lo que proporciona un ambiente favorable para el crecimiento de las bacterias oportunistas, las cuales agregadas a las limitaciones en el ámbito de salud oral son factores que inciden directamente en la salud bucal, causándole una serie de problemas de salud como alteraciones periodontal, caries, traumatismos teniendo como resultado la pérdida de piezas dentales. Este estudio plantea determinar el estado de salud oral en los pacientes internos del “Hospital José Dolores Fletes Valles” en el año 2014. Se realizó un estudio descriptivo, observacional de corte transversal basado en la inspección de la cavidad oral y la revisión de expedientes clínicos con un universo de 193 pacientes y una muestra de 129 con una confiabilidad del 95% y un error muestral del 5%, a los cuales se aplicaron los índices epidemiológicos CPOD, índice de placa visible simplificado (IPVS) e índice gingival reducido (IGR). Se determinó que de los 91 pacientes el 91.1% de estos paciente presentan acumulo de placa, el 99.9% presentan experiencia de caries y el 92.3 presentan gingivitis severa. Siendo también el trastorno mental más común esquizofrenia presentándose en el 33% de los pacientes seguido del trastorno orgánico con el 22%. Los resultados de este estudio llevan a concluir que la mayoría los pacientes presentaron la puntación máxima de los índice aplicados, lo que se interpreta como una deficiente salud oral de estos pacientes. Mismas que llevan a recomendar al centro hospitalario mejorar la atención de los paciente

Kinect as an access device for people with cerebral palsy: A preliminary study

Cerebral palsy (CP) describes a group of disorders affecting the development of movement and posture, causingactivity limitation. Access to technology can alleviate some of these limitations. Many studies have used vision- based movement capture systems to overcome problems related to discomfort and fear of wearing devices. Incontrast, there has been no research assessing the behavior of vision-based movement capture systems in peoplewith involuntary movements. In this paper, we look at the potential of the Kinect sensor as an assistive technologyfor people with cerebral palsy. We developed a serious game, called KiSens Números, to study the behavior ofKinect in this context and eighteen subjects with cerebral palsy used it to complete a set of sessions. The resultsof the experiments show that Kinect filters some of peoples involuntary movements, confirming the potential ofKinect as an assistive technology for people with motor disabilities

Fuzzy approach for data association in image tracking

A fuzzy system has been developed to ponder update decisions both for the trajectories and shapes estimated for targets. It is embedded in an A-SMGCS Surveillance function for airport surface, based on video data processing, in charge of the automatic detection, identification and tracking of all interesting targets (aircraft and relevant ground vehicles). The tracking system captures a sequence of images, preprocesses them to extract the moving regions (blobs), and associates the blobs to tracks to estimate the number of targets in the scenario and their parameters. The system was initially built with a set of rules derived from performance analysis, and then a procedure based on neuro-fuzzy techniques was applied to automatically obtain rules from examples. A validation of learned system shows its capability to produce appropriate decisions. Results obtained with real data in representative ground operations show the system capabilities to solve complex scenarios and improve tracking accuracy.Peer Reviewe