Developing discontinuous Galerkin methods for the resolution of the incompressible Navier-Stokes equations

Informe de investigación elaborado a partir de una estancia en el Laboratorio de Diseño Computacional en Aeroespacial en el Massachusetts Institute of Technology (MIT), Estados Unidos, entre noviembre de 2006 y agosto de 2007. La aerodinámica es una rama de la dinámica de fluidos referida al estudio de los movimientos de los líquidos o gases, cuya meta principal es predecir las fuerzas aerodinámicas en un avión o cualquier tipo de vehículo, incluyendo los automóviles. Las ecuaciones de Navier-Stokes representan un estado dinámico del equilibrio de las fuerzas que actúan en cualquier región dada del fluido. Son uno de los sistemas de ecuaciones más útiles porque describen la física de una gran cantidad de fenómenos como corrientes del océano, flujos alrededor de una superficie de sustentación, etc. En el contexto de una tesis doctoral, se está estudiando un flujo viscoso e incompresible, solucionando las ecuaciones de Navier- Stokes incompresibles de una manera eficiente. Durante la estancia en el MIT, se ha utilizado un método de Galerkin discontinuo para solucionar las ecuaciones de Navier-Stokes incompresibles usando, o bien un parámetro de penalti para asegurar la continuidad de los flujos entre elementos, o bien un método de Galerkin discontinuo compacto. Ambos métodos han dado buenos resultados y varios ejemplos numéricos se han simulado para validar el buen comportamiento de los métodos desarrollados. También se han estudiado elementos particulares, los elementos de Raviart y Thomas, que se podrían utilizar en una formulación mixta para obtener un algoritmo eficiente para solucionar problemas numéricos complejos.

Generador de gestores de contenido web en Java

Aquest projecte consisteix en el desenvolupament d'una aplicació web programada en Java, que permet crear diferents tipus de webs, donant l'opció de definir i administrar tant les estructures com els continguts dels apartats. Altres opcions que permet gestionar són els tipus d'usuaris que podran accedir i el disseny gràfic de cada web generada. S'aconsegueix així crear webs sense necessitat de programar. Mitjançant el desenvolupament del projecte es pretén aprendre i utilitzar el framewok anomenat Struts que ofereix una plataforma sobre la qual es desenvolupa l'aplicació permetent utilitzar una sèrie de llibreries ja programades i treballar utilitzant una metodologia o patró de disseny.

Building Capacity in Developing Countries : OER for Food Safety

The Food Safety Knowledge Network (FSKN) was developed through the collaboration of Michigan State University and a professional network of international food industry retailers and manufacturers. The key objective of the FSKN project is to provide technical resources, in a cost effective way, in order to promote food safety in developing countries and for small and less developed companies. FSKN uses a competency based model including a framework, OERs, and assessments. These tools are being used to support face-to-face training, fully online training, and to gauge the learning outcomes of a series of pilot groups which were held in India, Egypt, and China.

Informality and overeducation in the labor market of a developing country

In this paper, we explore the connection between labor market segmentation in two sectors, a modern protected formal sector and a traditional- unprotected-informal sector, and overeducation in a developing country. Informality is thought to have negative consequences, primarily through poorer working conditions, lack of social security, as well as low levels of productivity throughout the economy. This paper considers an aspect that has not been previously addressed, namely the fact that informality might also affect the way workers match their actual education with that required performing their job. We use micro-data from Colombia to test the relationship between overeducation and informality. Empirical results suggest that, once the endogeneity of employment choice has been accounted for, formal male workers are less likely to be overeducated. Interestingly, the propensity of being overeducated among women does not seem to be closely related to the employment choice.

A Simple Access Pricing Rule to Achieve the Ramsey Outcome in Two-Way Access

In this paper, I consider a general and informationally effcient approach to determine the optimal access rule and show that there exists a simple rule that achieves the Ramsey outcome as the unique equilibrium when networks compete in linear prices without network-based price discrimination. My approach is informationally effcient in the sense that the regulator is required to know only the marginal cost structure, i.e. the marginal cost of making and terminating a call. The approach is general in that access prices can depend not only on the marginal costs but also on the retail prices, which can be observed by consumers and therefore by the regulator as well. In particular, I consider the set of linear access pricing rules which includes any fixed access price, the Efficient Component Pricing Rule (ECPR) and the Modified ECPR as special cases. I show that in this set, there is a unique access rule that achieves the Ramsey outcome as the unique equilibrium as long as there exists at least a mild degree of substitutability among networks' services.

A aldraxe proverbial da preguiza nas dúas versións españolas de The Way to Wealth de Benjamin Franklin

A admiración que destilou no seu tempo e durante o século XIX o bo sentido común das obras de Benjamin Franklin (1706-1790) plasmouse na tradución dos seus libros a un considerable número de linguas. The Way to Wealth (El camino de la fortuna o Cómo hacerse rico), publicado en 1758, contén máis de cen máximas que instan ao traballo honrado, á orde e ao aforro, condenando calquera sinal de preguiza ou desidia. O noso corpus nútrese dunha selección de trece aforismos que teñen relación precisamente con este vicio que condena á miseria, a preguiza. En cambio, o home de ben que aplique as virtudes contidas en The Way to Wealth, aconselladas a modo de refráns, verá, segundo o autor, prosperar esplendidamente a súa economía. Pretendemos analizar, dende os puntos de vista tradutolóxico e contrastivo, o corpus de dúas traducións españolas deste libriño de Franklin: unha anónima, publicada en Barcelona, en 1891; e a de Alberto Lena de 1999.

'Situaciones problema' y desarrollo de la competencia motriz en educación física escolar: cuestiones didácticas = Problem situations and developing motor competence in Physical Education at school: didactic questions

From the areas of motor learning and the teaching of Physical Education we promote coherent methodological orientationswith the present curricular guide that are focused in such a way so that the student is able to act independently. In thissense we may consider the problem situations as a good example for methodological proposals. So as to determine its useand adequateness for Physical Education it is conveniente to analyse the characteristics of the motor tasks that areproposed as well as the features of the teaching intervention in such a way as to ease the adquisition and development ofthe motor competence of the students

An alternative way to model merit good arguments

Besley (1988) uses a scaling approach to model merit good arguments in commodity tax policy. In this paper, I question this approach on the grounds that it produces 'wrong' recommendations--taxation (subsidisation) of merit (demerit) goods--whenever the demand for the (de)merit good is inelastic. I propose an alternative approach that does not suffer from this deficiency, and derive the ensuing first and second best tax rules, as well as the marginal cost expressions to perform tax reform analysis.

Stochastic dominance and absolute risk aversion

In this paper we propose the infimum of the Arrow-Pratt index of absolute risk aversion as a measure of global risk aversion of a utility function. We then show that, for any given arbitrary pair of distributions, there exists a threshold level of global risk aversion such that all increasing concave utility functions with at least as much global risk aversion would rank the two distributions in the same way. Furthermore, this threshold level is sharp in the sense that, for any lower level of global risk aversion, we can find two utility functions in this class yielding opposite preference relations for the two distributions.

Reference prices: the spanish way

The aim of this paper is to analyse the effects of recent regulatory reforms that Spanish Health Authorities have implemented in the pharmaceutical market: the introduction of a reference price system together with the promotion of generic drugs. The main objectives of these two reforms are to increase price competition and, ultimately, reduce pharmaceutical costs. Before the introduction of reference prices, consumers had to pay a fixed copayment of the price of whatever drug purchased. With the introduction of such system, the situation differs in the following way: if (s)he buys the more expensive branded drug, then (s)he pays a sum of two elements: the copayment associated to the reference price plus the difference between the price of this good and the reference price. However, if the consumer decides to buy the generic alternative, with price lower than the reference price, then (s)he has to pay the same copayment as before. We show that the introduction of a reference price system together with the promotion of generic drugs increase price competition and lower pharmaceutical costs only if the reference price is set in a certain interval. Also profits for the duopolists might be reduced. These results are due to the opposing effects that reference prices have on branded and generic producers respectively.

El jove Martin Heidegger i el concepte de temps exposat a Ésser i temps

Estudi elaborat a partir d’una estada a l’ Albert Ludwigs Universität, Alemanya, entre els mesos de maig i octubre del 2006.El tema del temps és extremadament important per a Martin Heidegger. I el seu pensament al respecte no pot ésser comprès adequadament si no tenim en compte la gran influència que diversos filòsofs hi van exercir. Aristòtil i Agustí són elsmés destacats, tal i com el propi Heidegger afirma a les seves lliçons marburgueses del semestre d’estiu de 1927. Sense elles, no es pot entendre el complex entramat terminològic ni les idees fonamentals sobre la temporalitat. Idees que apareixen publicades en diverses obres seves. El transfons filosòfic de cadascun d’aquests escrits és, en part, el concepte aristotèlic o Agustina de temps. Ésser i temps no és una obra que neixi del no res com a producte de la necessitat de l’autor de consolidar el seu currículum en vistes a una plaça docent, sinó que la publicació durant aquests darrers anys de les seves lliçons i altres escrits menors permeten observar com es va gestant la manera en que Heidegger entendrà el concepte de temps que es reflexa en aquest tractat, i que, com ja s’ha dit, es sustenta en les idees d’Aristòtil i d’Agustí al respecte. S’ha mostrat també de quina manera Heidegger porta a la pràctica la reconstrucció fenomenològica proposada pel que va ser el seu mentor, Husser, i com recondueix els conceptes fonamentals d’ambdós filòsofs, incorporant-los a la seva particular manera d’entendre el temps.

A Retail benchmarking approach to eficient two-way access pricing

We study a retail benchmarking approach to determine access prices for interconnected networks. Instead of considering fixed access charges as in the existing literature, we study access pricing rules that determine the access price that network i pays to network j as a linear function of the marginal costs and the retail prices set by both networks. In the case of competition in linear prices, we show that there is a unique linear rule that implements the Ramsey outcome as the unique equilibrium, independently of the underlying demand conditions. In the case of competition in two-part tariffs, we consider a class of access pricing rules, similar to the optimal one under linear prices but based on average retail prices. We show that firms choose the variable price equal to the marginal cost under this class of rules. Therefore, the regulator (or the competition authority) can choose one among the rules to pursue additional objectives such as consumer surplus, network covera.

Preliminary study of cooperation in hybrid ad-hoc networks

In this paper, we present a first approach to evolve a cooperative behavior in ad hoc networks. Since wireless nodes are energy constrained, it may not be in the best interest of a node to always accept relay requests. On the other hand, if all nodes decide not to expend energy in relaying, then network throughput will drop dramatically. Both these extreme scenarios are unfavorable to the interests of a user. In this paper we deal with the issue of user cooperation in ad hoc networks by developing the algorithm called Generous Tit-For-Tat. We assume that nodes are rational, i.e., their actions are strictly determined by self-interest, and that each node is associated with a minimum lifetime constraint. Given these lifetime constraints and the assumption of rational behavior, we study the added behavior of the network.

Sistema de comunicació sense fils utilitzant Zigbee per PDA

En aquest projecte es presenta el disseny i desenvolupament d'un conjunt d'interfícies per a un sistema de comunicació basat en l'estàndard Zigbee. El sistema està composat per una tarja que integra el mòdul Zigbee, un microcontrolador i una FPGA, que es vol controlar des d'un sistema Pocket PC a través del port SD. La implementació consta d’un driver SDIO per Windows CE 4.2, el controlador SDIO a la FPGA i l'enllaç de comunicació entre la FPGA i el microcontrolador.