Hervada-Sala, C.; Jarauta-Bragulat, E.; Gibergans-Báguena, J.; Buenestado, P. Conference of the International Association for Mathematical Geology p. 1176-1184 Presentation's date: 2015-09-10 Presentation of work at congresses
Offshore wind energy is an alternative energy source of increased interest. A large offshore wind farms have been planned or under construction, mainly in northern Europe. One of the points needed to be able to implement offshore projects is to characterize and model the wind for marine generation. Models are needed for the design of the most appropriate control strategies. Some attempts have been done to do so; recently these models are implemented under a wind turbine block set in Matlab/Simulink. A handicap has been detected: adjustment of wind turbulence using a white noise function. In this paper, a modification of that model is presented, based on real data and a wind model block in Matlab/Simulink has been performed to implement a new noise function with better results than the standard white noise function.
Jarauta-Bragulat, E.; Egozcue, J. J.; Hervada-Sala, C.; Gibergans-Báguena, J. Conference of the International Association for Mathematical Geosciences p. 1321-1328 Presentation's date: 2015-09-09 Presentation of work at congresses
A compositional approach to air quality index (AQI) based on a log-contrast of pollutants over non-polluted air fraction was recently developed. This approach let to three open questions about consistency and formalization of such index. First question is to find out the conditions under which the approximation of the log-contrast by the logarithm of the geometric mean of pollutants concentrations, are reliable. Second, is to examine a way to define a reasonable scale for express air quality, taking into account the effects of air pollution on population health and on social or economic activity. The third one is to find out the properties of this kind of index with respect to the addition of a new set of air pollutants in the composition. To deal with these open questions, a decision making tree should be designed in order to select suitable weights on the air pollutants. A preliminary application study of air pollutants composition distribution in some cities is presented. In addition, the approach of the log-contrast by the logarithm of the weighted geometric mean is described for these cities.
Ortego, M.I.; Tolosana-Delgado, R.; Gibergans-Báguena, J.; Egozcue, J. J.; Sanchez-Arcilla, A. Environmental Risk and Extreme Events p. 10 Presentation's date: 2011-07-11 Presentation of work at congresses
The aim of this paper is to introduce a methodology for de¯ning groups from regionalized com- positional data, through a hierarchical clustering algorithm aware of both the spatial dependence and the compositional character of the data set. This method is used to de¯ne a regionalization of Catalunya (NE Spain) with respect to its precipitation patterns in the Winter season. This region is characterized by a highly contrasted topography, which plays a dominant role in the spatial distribution of precipitation. Each rain gauge station is characterized by the relative frequencies of occurrence of six intervals of daily precipitation amount (classes ranging from \no rain" for precipitation below 3 mm, to \heavy storm" above 50 mm). Recognizing that frequencies are com-positional data, the spatial dependence of this data set has been characterized by variograms of the set of all pair-wise log-ratios, in the fashion of the variation matrix. Then, a Mahalanobis distance between stations has been de¯ned using these variograms to ensure that gauges with high spatial correlation get smaller distances. This spatially-dependent distance criterion has been used in a Ward hierarhical cluster method to de¯ne the regions. Results reveal 5 quite homogeneous groups of stations, which can be mostly ascribed a physical meaning. Finally, possible links to regional circulation patterns are discussed.
A Point-Over-Threshold approach using a reparameterization of the Generalized Pareto Distribution (GPD) has been used to assess changes in the daily rainfall Barcelona series (1854–2006). A Bayesian approach, considering the suitable scale and physical features of the phenomenon, has been used to look for these alterations. Two different models have been assessed: existence of abrupt changes in the new GPD parameters due to modifications of the observatory locations and trends in these GPD parameters,
pointing to a climate change scenario.
En este trabajo se presentan los materiales "El análisis de datos estadístico en cooperación para el desarrollo: algunos casos prácticos", una herramienta docente que incorpora contenidos estadísticos y aplicaciones multidisciplinares. En el contexto de reforma hacia
el EEES es importante una formacion global, con competencias transversales más allá de las técnicas. La ETSECCPB ha impulsado un bloque de asignaturas de Cooperación cuya puesta en marcha hizo patente la necesidad de un enfoque estadístico de los contenidos.
Desde entonces se han ido recopilando casos prácticos y experiencias en diferentes ámbitos, conformando un conjunto de materiales utilizados en asignaturas de Cooperación y de Estadística. En las asignaturas donde han sido utilizados han tenido una buena acogida
por parte del alumnado y del profesorado. La colaboración con otros miembros de la comunidad universitaria permitirá adaptar y mejorar estos materiales para así ampliar sus contenidos y su ámbito de aplicación.