Homogenization of variational problems in manifold valued BV-spaces

This paper extends the result of \cite{BM} on the homogenization of integral functionals with linear growth defined for Sobolev maps taking values in a given manifold. Through a $\Gamma$-convergence analysis, we identify the homogenized energy in the space of functions of bounded variation. It turns out to be finite for $BV$-maps with values in the manifold. The bulk and Cantor parts of the energy involve the tangential homogenized density introduced in \cite{BM}, while the jump part involves an homogenized surface density given by a geodesic type problem on the manifold.Comment: 32 page

Homogenization of variational problems in manifold valued Sobolev spaces

Homogenization of integral functionals is studied under the constraint that admissible maps have to take their values into a given smooth manifold. The notion of tangential homogenization is defined by analogy with the tangential quasiconvexity introduced by Dacorogna, Fonseca, Maly and Trivisa \cite{DFMT}. For energies with superlinear or linear growth, a $\Gamma$-convergence result is established in Sobolev spaces, the homogenization problem in the space of functions of bounded variation being the object of \cite{BM}.Comment: 22 page

The near-extreme density of intraday log-returns

The extreme event statistics plays a very important role in the theory and practice of time series analysis. The reassembly of classical theoretical results is often undermined by non-stationarity and dependence between increments. Furthermore, the convergence to the limit distributions can be slow, requiring a huge amount of records to obtain significant statistics, and thus limiting its practical applications. Focussing, instead, on the closely related density of "near-extremes" -- the distance between a record and the maximal value -- can render the statistical methods to be more suitable in the practical applications and/or validations of models. We apply this recently proposed method in the empirical validation of an adapted financial market model of the intraday market fluctuations

The use of figures in the evaluation or rural development policies: a quest for knowledge Counting, to tell and understand

Using figures seems to create rigour, objectivity, knowledge and it facilitates comparisons. Consequently, an evalution without figures is hardly conceivable. Nonetheless, objectivity and precision can be just an impression given the fact that figures are constructions built on a modeled description of reality. The simplification of reality operated through a figure can hide subtle elements regarding the way public policies work. If figures can legitimately be used in evaluation, every kinds of figures and evaluations are not equivalent. Therefore, our main research question is what place for figures in evalution? This contribution relates to research about policy evaluation, seen as a mean to produce knowledge useful for the understanding of policies and their implementation. Based on the analysis of the evaluations of rural development policies conducted by the French ministry of agriculture our goal is to increase practical and theoretical knowledge of those policies through well-designed evalutions.Data, evaluation, methods, rural development policies, Agricultural and Food Policy, R58, Q18, H50,

Leaking method approach to surface transport in the Mediterranean Sea from a numerical ocean model

We use Lagrangian diagnostics (the leaking and the exchange methods) to characterize surface transport out of and between selected regions in the Western Mediterranean. Velocity fields are obtained from a numerical model. Residence times of water of Atlantic origin in the Algerian basin, with a strong seasonal dependence, are calculated. Exchange rates between these waters and the ones occupying the northern basin are also evaluated. At surface, northward transport is dominant, and involves filamental features and eddy structures that can be identified with the Algerian eddies. The impact on these results of the presence of small scale turbulent motions is evaluated by adding Lagrangian diffusion.Comment: 21 pages using the elsart style. Higher resolution figures available from http://www.imedea.uib.es/physdept/publications/showpaper_en.php?indice=119