University of Avignon

About: University of Avignon is a education organization based out in Avignon, Provence-Alpes-Côte-d'Azur, France. It is known for research contribution in the topics: Population & Speaker recognition. The organization has 1526 authors who have published 3766 publications receiving 88928 citations.

A User's View of the Parameters Derived from the Induction Curves of Maximal Chlorophyll a Fluorescence: Perspectives for Analyzing Stress.

Abstract: Analysis of the fast kinetics of the induction curve of maximal fluorescence represents a relatively recent development for chlorophyll a fluorescence (ChlF) measurements. The parameters of the so-called JIP-test are exploited by an increasingly large community of users to assess plant stress and its consequences. We provide here evidence that these parameters are capable to distinguish between stresses of different natures or intensities, and between stressed plants of different genetic background or at different developmental stages at the time of stress. It is however important to keep in mind that the JIP-test is inherently limited in scope, that it is based on assumptions which are not fully validated and that precautions must be taken to ensure that measurements are meaningful. Recent advances suggest that some improvements could be implemented to increase the reliability of measurements and the pertinence of the parameters calculated. We moreover advocate for using the JIP-test in combination with other techniques to build comprehensive pictures of plant responses to stress.

Microwave turbo hydrodistillation for rapid extraction of the essential oil from Schinus terebinthifolius Raddi Berries

Abstract: We have developed a novel microwave turbo hydrodistillation (MTHD) apparatus and have used it to extract hard, dry plant materials, for example bark, roots, and seeds. To demonstrate its feasibility, MTHD was used for extraction of dry Schinus terebinthifolius raddi berries. Although the essential oil isolated by MTHD was quantitatively (yield) and qualitatively (aromatic profile) similar to that obtained by turbo hydrodistillation (THD), MTHD was more rapid than THD (30 min compared with 180 min), thereby enabling substantial saving of time and energy. These results show that MTHD enables simple and rapid analysis of volatile compounds.

Query Expansion and Classification of Retrieved Documents.

Abstract: This paper presents different methods tested by the University of Avignon and Bertin at the TREC-7 evaluation A first section describes several methodologies used for query expansion: synonymy and stemming Relevance feedback is applied both to the TIPSTER corpora and Internet documents In a second section, we describe a classification algorithm based on hierarchical and clustering methods This algorithm improves results given by any Information Retrieval system (that retrieves a list of documents from a query) and helps the users by automatically providing a structured document map from the set of retrieved documents Lastly, we present the first results obtained with TREC-6 and TREC7 corpora and queries by using this algorithm keywords: ad-hoc information retrieval, automatic relevance feedback, synonymy, automatic classification, cluster-based and hierarchical methods

Three-dimensional Anosov flag manifolds

Abstract: Let $\Gamma$ be a surface group of higher genus Let $\rho_0: \Gamma \rightarrow \mbox{PGL}(V)$ be a discrete faithful representation with image contained in the natural embedding of $\mbox{SL}(2, {\mathbb R})$ in $\mbox{PGL}(3, {\mathbb R})$ as a group preserving a point and a disjoint projective line in the projective plane We prove that such a representation is $(G,Y)$-Anosov (following the terminology of \cite{labourieanosov}), where $Y$ is the frame bundle More generally, we prove that all the deformations $\rho: \Gamma \rightarrow \mbox{PGL}(3, {\mathbb R})$ studied in \cite{barflag} are $(G,Y)$-Anosov As a corollary, we obtain all the main results of \cite{barflag}, and extend them to any small deformation of $\rho_0$, not necessarily preserving a point or a projective line in the projective space: in particular, there is a $\rho(\Gamma)$-invariant solid torus $\Omega$ in the flag variety The quotient space $\rho(\Gamma)\backslash\Omega$ is a flag manifold, naturally equipped with two $1$-dimensional transversely projective foliations arising from the projections of the flag variety on the projective plane and its dual; if $\rho$ is strongly irreducible, these foliations are not minimal More precisely, if one of these foliations is minimal, then it is topologically conjugate to the strong stable foliation of a double covering of a geodesic flow, and $\rho$ preserves a point or a projective line in the projective plane All these results hold for any $(G,Y)$-Anosov representation which is not quasi-Fuchsian, ie, does not preserve a strictly convex domain in the projective plane

Solving New Urban Freight Distribution Problems Involving Modular Electric Vehicles

Abstract: Vehicle routing problem (VRP) have been intensively studied over the past few years. Indeed, a strong strand of research is devoted to aid freight companies or public authorities in making their decisions. Nowadays, new solutions are proposed that take into account new technologies enabling the design of electric vehicles which can be used in new mobility schemes or help fleet owners stay competitive when delivering freight. In this study, the aim is to investigate the innovative concept of modular electric vehicles for goods delivery in cities. More precisely, the vehicles considered in this study can be split into two or several modules which can be let at a dedicated location and retrieved later during a run for charging purposes or to gain agility. The objective is then to address the challenging issues associated with the use of these new modular electric vehicles for urban freight transport. It is a completely new problem integrating both the complexity of the original VRP and specific constraints induced by using modular electric vehicles in urban environment. This study presents a first formulation of this problem together with a complete effective solving approach which shows promising results.