Performance of the ambient tax: does the nature of the damage matter?

The ambient tax is often considered as an effcient instrument to achieve a …rst best outcome of ambient pollution when the regulator is less informed than the polluters. Since the ambient tax was never imple- mented in the …eld, empirical evidence is missing. Available experimental …ndings provide mixed evidence: effciency is higher under external dam- age, i.e. if ambient pollution affects non-polluters (Spraggon, 2002, 2003) than under internal damage, i.e. if ambient pollution a¤ects polluters themselves (Cochard et al., 2005). Since these two types of experiments relied on very different designs, it is worthwhile to compare them under a common experimental design. Our main …nding is that the ambient tax is equally effcient under external damage than under internal damage.

A model of individual clustering with vanishing diffusion

17International audienceWe consider a model of individual clustering with two specific reproduction rates and small diffusion parameter in one space dimension. It consists of a drift-diffusion equation for the population density coupled to an elliptic equation for the velocity of individuals. We prove the convergence (in suitable topologies) of the solution of the problem to the unique solution of the limit transport problem, as the diffusion coefficient tends to zero

Path computation in multi-layer networks: Complexity and algorithms

Carrier-grade networks comprise several layers where different protocols coexist. Nowadays, most of these networks have different control planes to manage routing on different layers, leading to a suboptimal use of the network resources and additional operational costs. However, some routers are able to encapsulate, decapsulate and convert protocols and act as a liaison between these layers. A unified control plane would be useful to optimize the use of the network resources and automate the routing configurations. Software-Defined Networking (SDN) based architectures, such as OpenFlow, offer a chance to design such a control plane. One of the most important problems to deal with in this design is the path computation process. Classical path computation algorithms cannot resolve the problem as they do not take into account encapsulations and conversions of protocols. In this paper, we propose algorithms to solve this problem and study several cases: Path computation without bandwidth constraint, under bandwidth constraint and under other Quality of Service constraints. We study the complexity and the scalability of our algorithms and evaluate their performances on real topologies. The results show that they outperform the previous ones proposed in the literature.Comment: IEEE INFOCOM 2016, Apr 2016, San Francisco, United States. To be published in IEEE INFOCOM 2016, \<http://infocom2016.ieee-infocom.org/\&g

Global existence of solutions to a parabolic-elliptic chemotaxis system with critical degenerate diffusion

19 pagesInternational audienceAbstract: This paper is devoted to the analysis of non-negative solutions for a degenerate parabolic-elliptic Patlak-Keller-Segel system with critical nonlinear diffusion in a bounded domain with homogeneous Neumann boundary conditions. Our aim is to prove the existence of a global weak solution under a smallness condition on the mass of the initial data, there by completing previous results on nite blow-up for large masses. Under some higher regularity condition on solutions, the uniqueness of solutions is proved by using a classical duality technique

Algorithme incrémental pour les graphes de voisins relatifs

National audienceNeighborhood graphs know increasing use in many fields as in Data Science, or Multi-dimensional data Indexing. This interest is the result of their ability to express similarity and closeness in both an intuitive and efficient manner, but also because of the emergence of graph databases and graph computation frameworks. In this short paper we propose a fast exact incremental procedure for the construction of Relative Neighborhood Graphs, and then inspired by previous work, we propose a faster heuristic methodLes graphes de proximité connaissent un usage conséquent ces dernières années comme alternatives aux méthodes traditionnelles de classification et d'indexation de données. Dans ce travail, nous proposons une méthode exacte pour la mise à jour de graphes de voisins relatifs, et nous proposons une heuristique plus efficace en combinant notre approche avec des travaux existants

Classification de formes par apprentissage des géodésiques de formes

National audienceDans un travail précédent, nous avons proposé une méthode de reconnaissance de formes (classification et recherche) basée sur le recalage et les géodésiques de formes. Dans cet article, nous y introduisons une étape supplémentaire d'estimation de pose pour l'accélération du temps de traitement. Nous montrons ensuite que les géodésiques de formes peuvent également être utilisées par des techniques de classification de type SVM ou forêts aléatoires. Les expérimentations menées sur la base de formes MPEG-7 montrent (1) une réduction du temps de calcul des attributs caractéristiques d'un facteur dix en moyenne, et (2) une amélioration du taux de bonne classification par rapport au classifieur plus proche voisin : En analyse mono-échelle : Plus proche voisin (95, 05%), Forêt aléatoire (96, 10%), SVM (97, 66%). En analyse multi-échelle : Plus proche voisin (98, 86%), Forêt aléatoire (99, 02%), SVM (99, 44%). Abstract – In a previous work, we proposed a method of pattern recognition (classification and retreival) based on signal registration and shape geodesics. In this paper, we introduce a preliminary step of pose estimation for accelerating the processing time. We then show that shape geodesics may also be used by classification techniques such as SVM and random forest algorithms. Experiments conducted on the shapes of the benchmark database MPEG-7 show (1) a reduction in computation time of the attributes of a factor of ten in average, and (2) an improvement in the classification rate compared to the nearest neighbor classifier: In single-scale analysis: Nearest Neighbor (95.05%), Random Forest (96.10%), SVM (97.66%). Multi-scale analysis: Nearest Neighbor (98.86%), random forest (99.02%), SVM (99.44%)

Chemically modified polysulfones for molecular imprinting. Synthesis and complexation with a fluorescent model template

Polysulfone (PSU) was chemically modified to prepare new molecular imprinted membranes (MIMs). Several amounts of amine and sulfonyl groups were introduced into the PSU chemical structure in order to create interactions with acid or base templates, such as biomolecules or biomacromolecules. A fluorescent dye, Acridine Orange base (AO), was used as a model template and its complexation with the prepared PSUs was monitored by spectroscopic techniques. This study showed an absence of complexation with the native PSU and a strong complexation with the aminated and the sulfonated PSUs. Partially allylated PSU bearing amine or sulfonyl groups were also synthesized. These compounds are expected to be used as precursors for designing new crosslinked molecular imprinting membranes (MIMs), exhibiting high stability of the template memory

Reconnaissance de parties de formes basée sur les géodésiques de formes

National audienceLes performances du système de reconnaissance de formes dépendent en grande partie de la qualité de l'image segmentée. Comme la segmentation complète est loin d'être toujours atteinte, nous abordons dans ce travail le problème de la reconnaissance de parties de formes. Nous nous plaçons dans le cas où seulement certaines parties de la forme entière sont disponibles. A cet effet, nous proposons une stratégie de reconnaissance basée sur les géodésiques dans l'espace de formes. Nous montrons que la mesure de similarité ainsi définie permet de gérer efficacement les déformations élastiques de formes. Les tests effectués sur des parties de formes de la base MPEG-7 et sur des parties issues d'images segmentées démontrent l'efficacité de notre schéma de reconnaissance. Abstract The performance of a pattern recognition system heavily depends on image segmentation quality. Since a complete segmentation cannot be always reached, we address here the problem of shape parts recognition where only some parts of the entire shape are available. For this purpose, we propose a recognition strategy that uses geodesics-based distance able to handle elastic deformations and articulations. Experiments carried out on parts of shapes of the MPEG-7 database and on parts issued from segmented images demonstrate the effectiveness of our proposed scheme

Reconnaissance automatique de gestes manuels en langue des signes

National audienceNous abordons dans ce papier la reconnaissance automa-tique de gestes manuels statiques pour des applications en langue des signes. Dans un travail précédent, nous avons proposé une méthode de reconnaissance de formes (classification et recherche) basée sur le recalage et les géodé-siques de formes. Cette méthode est conçue pour être ro-buste aux points aberrants et aux variabilités interindivi-duelles. Cette robustesse peut parfois mener à des confusions lorsque nous travaillons avec des classes de formes à faible dissemblance et donc à faible séparabilité. La diffé-rence entre ces classes de formes serait considérée comme donnée aberrante. Dans cet article, nous révisons notre méthode de reconnaissance de formes pour bien s'adap-ter aux classes à faible dissemblance. Nous nous plaçons en particulier dans le contexte de la reconnaissance de gestes manuels. Les résultats expérimentaux sur la base de référence GESTURES montrent tout l'intérêt de notre approche. Mots Clefs Langue de signes, reconnaissance de formes, recalage, ro-bustesse. Abstract This paper deals with the static hand gesture recognition for sign language applications. In a previous work, we proposed a method of pattern recognition (classification and research) based on robust registration and shapes geode-sics. This robustness may lead sometimes to errors when dealing with databases with low variability among shape classes so low separability. The difference between these classes could be interpreted as aberrant data. In this paper , we revise and adjust our method to be adapted for classes with low dissimilarity. We consider particularly the problem of gesture recognition. Experimental results on the GESTURES test base show the advantage of our approach