Variational mechanics and numerical methods for structural analysis

This work focuses on the particular application of the variational principles of Lagrange and Hamilton for structural analysis. Different numerical methods are compared in their computation of the elastic energy through time. According to variational mechanics, the difference between the stored elastic energy and the applied work should be null on each time step, so by computing this difference we can account for the level of accuracy of each combination of numerical methods. Moreover, in some situations when numerical instabilities are difficult to perceive due to high complexities, this procedure allows for the control and straightforward visualization of them, being an excellent source of hindsight on the behaviour of the analysed system. The purpose of this dissertation is to present a scheme where the current numerical methods can be benchmarked in a qualitative as well as in a quantitative manner. It is shown how different combinations of methods, even for a simple model, can give very different results, particularly in the field of dynamics, where often also instabilites arise. The first half of the thesis is a thorough explanation of these concepts and their application in terms of structural analysis. In the second part, a review on the numerical methods in general and of those implemented for our experiments is provided, followed by the experimental results and their interpretation. The model of choice, for simplicity and availability of analytical results is one cantilever column. Bending elastic energy of the column is monitored under transient regimes of different shapes, computing the total action of the system as its integral through time

La incidencia de la práctica físico-deportiva de los padres hacia sus hijos durante la infancia y la adolescencia

Se ha realizado una investigación sobre los hábitos de vida en relación con la salud, concretamente sobre la relación existente entre los hábitos de práctica de actividad física en escolares de primaria y secundaria obligatoria, en función de la práctica físico-deportiva por parte de sus padres. Para realizar dicha investigación se han utilizado cuestionarios validados mediante dos estudios piloto dobles, con las respuestas a un primer y segundo cuestionario readaptado, por medio de un grupo control en cada uno de los niveles educativos mencionados. Los resultados del estudio confirman una clara involución de la práctica física en el paso de un nivel educativo a otro, existiendo diferencias estadísticamente significativas a favor de los varones. Del mismo modo, el hábito de practicar actividad física frecuentemente tanto el padre como la madre del joven favorece una mayor participación deportiva por parte del escola

Notables andaluces transterrados en Iberoamérica

Tomo II ; págs. 3-1

A survey of real-time crowd rendering

In this survey we review, classify and compare existing approaches for real-time crowd rendering. We first overview character animation techniques, as they are highly tied to crowd rendering performance, and then we analyze the state of the art in crowd rendering. We discuss different representations for level-of-detail (LoD) rendering of animated characters, including polygon-based, point-based, and image-based techniques, and review different criteria for runtime LoD selection. Besides LoD approaches, we review classic acceleration schemes, such as frustum culling and occlusion culling, and describe how they can be adapted to handle crowds of animated characters. We also discuss specific acceleration techniques for crowd rendering, such as primitive pseudo-instancing, palette skinning, and dynamic key-pose caching, which benefit from current graphics hardware. We also address other factors affecting performance and realism of crowds such as lighting, shadowing, clothing and variability. Finally we provide an exhaustive comparison of the most relevant approaches in the field.Peer ReviewedPostprint (author's final draft

MeshPipe: a Python-based tool for easy automation and demonstration of geometry processing pipelines

The popularization of inexpensive 3D scanning, 3D printing, 3D publishing and AR/VR display technologies have renewed the interest in open-source tools providing the geometry processing algorithms required to clean, repair, enrich, optimize and modify point-based and polygonal-based models. Nowadays, there is a large variety of such open-source tools whose user community includes 3D experts but also 3D enthusiasts and professionals from other disciplines. In this paper we present a Python-based tool that addresses two major caveats of current solutions: the lack of easy-to-use methods for the creation of custom geometry processing pipelines (automation), and the lack of a suitable visual interface for quickly testing, comparing and sharing different pipelines, supporting rapid iterations and providing dynamic feedback to the user (demonstration). From the user's point of view, the tool is a 3D viewer with an integrated Python console from which internal or external Python code can be executed. We provide an easy-to-use but powerful API for element selection and geometry processing. Key algorithms are provided by a high-level C library exposed to the viewer via Python-C bindings. Unlike competing open-source alternatives, our tool has a minimal learning curve and typical pipelines can be written in a few lines of Python code.Peer ReviewedPostprint (published version

Pericles y el ideal de la democracia ateniense

Desde la sociedad heroica hasta los tiempos en que el imperio macedón de Filipo y Alejandro pone punto final a su ciclo histórico, el devenir de la polis helena en general, y el de Atenas en particular, vio su curso alterado por un buen número de revoluciones en su estructura político-social. La historia constitucional de la polis ateniense legada por Aristóteles no recoge la partida de defunción de la misma, pero entre la «constitución antigua» en que inicia y la «actual organización constitucional» en que acaba su autor cataloga nada menos que once cambios institucionales, que llevan desde la primitiva condición, en la que las «magistraturas se designaban entre los notables y ricos» —y en la cual, por decirlo con Weber, «ciudadano» no significaba otra cosa que «compañero de linaje»—, hasta la democrática vigente, opuesta en esencia a la anterior a pesar de las estrictas restricciones legales para el acceso a la ciudadanía. De la primera, la obra homérica nos sigue brindando uno de sus retratos más vívidos e indelebles; de la última, los discursos de Pericles —el segundo sobre todo— referidos en la obra de Tucídides ofrecen uno de los más acabados frescos acerca de su naturaleza; y ello pese a su tono, demasiado genérico o demasiado concreto; a que la realidad ateniense no guarda escrupulosa fidelidad al discurso que la magnífica e igualmente pese al hecho que Pericles y Aristóteles no estén haciendo referencia al mismo periodo democrático