Un modelo de elementos finitos mixtos para la resolución del problema del contacto elástico

Se aborda el problema del contacto elástico haciendo uso del método de los multiplicadores de Lagrange, dando lugar a un modelo de elementos finitos mixtos. Se introduce explícitamente una ley de fricción no-lineal e implícitamente un carácter no local para la misina. Para'evitar oscilaciones de la variable tensión en las proximidades de puntos singulares, se considera la formulación de un funcional lagragiano perturbado. Los algoritmos propuestos liberan posibles dependencias nodales de los cuerpos contactores, permitiendo la discretización independiente de ambos, y el contacto siinultáneo en zonas distintas de geometría cualquiera. La implementación en el ordenador se ha limitado a los casos plano y axisimétrico.The static elastic contact problein is faced up through Lagrange multipliers, leading to a inixed finite element problem. A non linear friction law is introduced explicitly and the non local character of the friction phenomena is taken into account in an implicit way. In order to avoid stress oscilations near singular points a perturbed lagrangian functional is considered. The algorithiiis lierein proposed do not iinpose nodal dependencies over the contacting surfaces, letting tlie independent discretization of both bodies. The inethod is able to model simultaneous contact over differeiit regions of any geoinetrical shape. Coinputer code, exainples and results liere presented, are restricted to axisyininetrical and bidimensional cases.Peer Reviewe

Un modelo de elementos finitos mixtos para la resolución del problema del contacto elástico

Se aborda el problema del contacto elástico haciendo uso del método de los multiplicadores de Lagrange, dando lugar a un modelo de elementos finitos mixtos. Se introduce explícitamente una ley de fricción no-lineal e implícitamente un carácter no local para la misina. Para'evitar oscilaciones de la variable tensión en las proximidades de puntos singulares, se considera la formulación de un funcional lagragiano perturbado. Los algoritmos propuestos liberan posibles dependencias nodales de los cuerpos contactores, permitiendo la discretización independiente de ambos, y el contacto siinultáneo en zonas distintas de geometría cualquiera. La implementación en el ordenador se ha limitado a los casos plano y axisimétrico.The static elastic contact problein is faced up through Lagrange multipliers, leading to a inixed finite element problem. A non linear friction law is introduced explicitly and the non local character of the friction phenomena is taken into account in an implicit way. In order to avoid stress oscilations near singular points a perturbed lagrangian functional is considered. The algorithiiis lierein proposed do not iinpose nodal dependencies over the contacting surfaces, letting tlie independent discretization of both bodies. The inethod is able to model simultaneous contact over differeiit regions of any geoinetrical shape. Coinputer code, exainples and results liere presented, are restricted to axisyininetrical and bidimensional cases.Peer Reviewe

Secret and the city.

The city is an ambivalent scene within the Sociology of secrecy as Social Space-Time. Understanding secrecy as a social practice that includes keeping, sharing or revealing, the city provides some opportunities for the success or the failure of all of the above-mentioned categories. As Simmel advised, the urbanism, the intensity of contacts and the relationship between the public, the private and the intimate, are the elements that allow for the development of secrets in the city. The image of a wasted city, in which the individual is alienated, is only right to a certain extent. Regarding secrecy, the indifference of the city can be the key to the success of a secret. Neighbourhoods or urban practices provide the possibilities to make a bubble of intimacy in the heart of each city

Regional Yield Insurance for Arable Crops in EU-27

Replaced with revised version of paper 11/18/08.Area yield insurance, index insurance, yield risk, Agricultural Finance, Risk and Uncertainty,

Revisiting Rose's common currency debate

The main objective of this research is to revisit the estimation of the effect of a common currency on international trade by applying the new methodology proposed by Helpman, Melitz and Rubistein (2008) and incorporating tourism to the theoretical framework. Rose (2000) estimates an empirical model of bilateral trade, finding a significant coefficient for a currency union variable of 1.2, suggesting an effect of currency unions on trade of over a 200%. Rose (2000)’s finding did not receive full acceptance and further research was consequently devoted to find reasons of such high effect. This still remains as a major puzzle in the International Economics. Rose and Van Wincoop (2001) hold that there may still be some omitted factors that drives countries to both participate in currency unions and trade more. In this research a gravity equation for trade is estimated controlling by international tourism.Common currency, tourism, gravity equation

On the impact of exchange rate regimes on tourism

The main objective of this paper is to analyze the effect of the exchange rate arrangements on international tourism. The ambiguity of literature about the effect of exchange rate volatility contrasts with the magnitude of the impact of a common currency on trade. On the basis of a gravity equation we estimate a moderate effect of a currency union on tourism of almost 12%. Furthermore, we estimate a gravity equation for international trade, obtaining that the common currency effect on trade is reduced when tourism is introduced as a regressor. This suggests that tourism flows may contribute to explain the excessive magnitude of the estimated effect of a common currency on trade in this literature. Finally, we analyze the impact of several de facto exchange rate arrangements on tourism, finding that less flexible exchange rates promotes tourism flows.Tourism, Exchange Rate Regime, Common Currency

¡Gamificad, insensatos!

El auge de la Gamificación en los últimos años parece imparable. Cientos de publicaciones, cursos y charlas nos dan pautas, recetas, experiencias y formas de convertir actividades “serias” en experiencias de juego gratificantes. La enseñanza no podía ser menos y también se está adentrando en el mundo de la diversión que emana del diseño de los videojuegos. Pese a todo, desgarradores lamentos y llantos desconsolados se siguen oyendo por los pasillos de los departamentos. Sollozos que anhelan estudiantes trabajadores, motivados, que lean, entiendan y presten atención, que estudien y pregunten o, por lo menos, que muestren respeto en clase. En la desesperada huida de las clases tradicionales, la Gamificación se presenta como el mesías que traerá un nuevo reinado de paz y prosperidad educativa. Además, las recetas son tan claras y lgorítmicas que ya han aparecido las primeras webs y servicios que nos añaden la capa de diversión a nuestras clases automáticamente. “Un clic aquí y dos allá y tus estudiantes nunca volverán a ser los mismos”, nos dicen. A veces los profesores parecemos principiantes: otros han tenido que venir a ponerle el palo a nuestro mocho. ¿Y qué es lo que debemos hacer ahora? Este artículo presenta un combate intelectual entre la Gamificación actual, tal y como se predica por doquier, y la experiencia acumulada de un grupo de profesores que lleva años utilizando los videojuegos y la filosofía de juego en la enseñanza. El punto de vista es crítico y práctico a la par, con la intención de transmitir las lecciones aprendidas y, sobre todo, los errores comunes en la concepción y aplicación de la Gamificación. Aviso: este artículo contiene subjetividad explícita e intencionada. No se ha maltratado ningún método científico, pero tampoco se le han hecho arrumacos.Gamification is growing unstoppable in latest years. Hundreds of publications, courses and talks give us guidelines, recipes, experiences and new ways of transforming “serious” activities into joyful playing experiences. Education has also joined the funny world that comes from game design, as you might expect. However, heartbreaking moans and desperate sobs continue to fill up departamental corridors. Sobs that yearn for diligent, motivated students; those who read, pay attention and understand, who study and ask questions..., or, at least, who show some respect during lessons. In this desperate escape from traditional lessons, Gamification shows itself as a kind of new messiah that will bring a new kingdom of peaceful and thriving education. Moreover, as recipes are so simple and algorithmical, they have given birth to websites and services that offer us an easy way to add fun to our lessons. “One click here, two there and your students will never be the same”, they ensure to us. Sometimes, we teachers seem novices: others have come before to add a stick to our mops. What are we supposed to do now? This paper presents an intelectual fighting between present Gamification models, as they are shown everywhere, and the accumulated experience of a group of teachers that have been usig games and game philosophy in their lessons for years. The analysis perspective is both critical and practical, with the aim of showing the lessons learnt together with misconceptions and common pitfalls in putting Gamification into practice. Warning: this paper contains explicit and planned subjectivity. Although no scientific method has been abused, none has received endearments

Complex network modeling of EEG band coupling in dyslexia: An exploratory analysis of auditory processing and diagnosis

Complex network analysis has an increasing relevance in the study of neurological disorders, enhancing the knowledge of brain’s structural and functional organization. Network structure and efficiency reveal different brain states along with different ways of processing the information. This work is structured around the exploratory analysis of the brain processes involved in low-level auditory processing. A complex network analysis was performed on the basis of brain coupling obtained from electroencephalography (EEG) data, while different auditory stimuli were presented to the subjects. This coupling is inferred from the Phase-Amplitude coupling (PAC) from different EEG electrodes to explore differences between control and dyslexic subjects. Coupling data allows the construction of a graph, and then, graph theory is used to study the characteristics of the complex networks throughout time for control and dyslexic subjects. This results in a set of metrics including clustering coefficient, path length and small-worldness. From this, different characteristics linked to the temporal evolution of networks and coupling are pointed out for dyslexics. Our study revealed patterns related to Dyslexia as losing the small-world topology. Finally, these graph-based features are used to classify between control and dyslexic subjects by means of a Support Vector Machine (SVM).Spanish Government PGC2018-098813-B-C32Junta de Andalucia UMA20-FEDERJA-086European CommissionNVIDIA CorporationMinistry of Science and Innovation, Spain (MICINN) Spanish GovernmentEuropean CommissionUniversidad de Malaga/CBU