858 research outputs found

    A fuzzy clustering algorithm to detect planar and quadric shapes

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    In this paper, we introduce a new fuzzy clustering algorithm to detect an unknown number of planar and quadric shapes in noisy data. The proposed algorithm is computationally and implementationally simple, and it overcomes many of the drawbacks of the existing algorithms that have been proposed for similar tasks. Since the clustering is performed in the original image space, and since no features need to be computed, this approach is particularly suited for sparse data. The algorithm may also be used in pattern recognition applications

    Morphologie urbaine et mobilité : outils et méthodes d’analyse conjointe des bases de données morphologiques et de mobilité

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    International audienceOur proposal is on the first hand to present the Remus model and its abilities to analyse urban morphological patterns; and on the second hand to present the first results obtained by characterizing the relations between morphology and mobility, using multiple regression models and landscape metrics.Ce projet de communication propose une méthode de caractérisation de la morphologie des tissus urbains, du point de vue des proximités, de l‘accessibilité et du fonctionnement des mobilités, par des indicateurs de graphes et des indicateurs morphologiques. Ces indicateurs sont ensuite réutilisés pour être confrontés à des indicateurs de mobilité, afin d’étudier les liens entre les morphologies territoriales et urbaines et les mobilités

    Dynamic Clustering of Histogram Data Based on Adaptive Squared Wasserstein Distances

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    This paper deals with clustering methods based on adaptive distances for histogram data using a dynamic clustering algorithm. Histogram data describes individuals in terms of empirical distributions. These kind of data can be considered as complex descriptions of phenomena observed on complex objects: images, groups of individuals, spatial or temporal variant data, results of queries, environmental data, and so on. The Wasserstein distance is used to compare two histograms. The Wasserstein distance between histograms is constituted by two components: the first based on the means, and the second, to internal dispersions (standard deviation, skewness, kurtosis, and so on) of the histograms. To cluster sets of histogram data, we propose to use Dynamic Clustering Algorithm, (based on adaptive squared Wasserstein distances) that is a k-means-like algorithm for clustering a set of individuals into KK classes that are apriori fixed. The main aim of this research is to provide a tool for clustering histograms, emphasizing the different contributions of the histogram variables, and their components, to the definition of the clusters. We demonstrate that this can be achieved using adaptive distances. Two kind of adaptive distances are considered: the first takes into account the variability of each component of each descriptor for the whole set of individuals; the second takes into account the variability of each component of each descriptor in each cluster. We furnish interpretative tools of the obtained partition based on an extension of the classical measures (indexes) to the use of adaptive distances in the clustering criterion function. Applications on synthetic and real-world data corroborate the proposed procedure

    Confidence-Guided Data Augmentation for Deep Semi-Supervised Training

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    We propose a new data augmentation technique for semi-supervised learning settings that emphasizes learning from the most challenging regions of the feature space. Starting with a fully supervised reference model, we first identify low confidence predictions. These samples are then used to train a Variational AutoEncoder (VAE) that can generate an infinite number of additional images with similar distribution. Finally, using the originally labeled data and the synthetically generated labeled and unlabeled data, we retrain a new model in a semi-supervised fashion. We perform experiments on two benchmark RGB datasets: CIFAR-100 and STL-10, and show that the proposed scheme improves classification performance in terms of accuracy and robustness, while yielding comparable or superior results with respect to existing fully supervised approachesComment: 7 page

    ESAT-6 Secretion-Independent Impact of ESX-1 Genes espF and espG1 on Virulence of Mycobacterium tuberculosis

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    Background. The pathogenesis of Mycobacterium tuberculosis largely depends on the secretion of the 6-kD early secreted antigenic target ESAT-6 (EsxA) and the 10-kD culture filtrate protein CFP-10 (EsxB) via the ESX-1/typeVII secretion system. Although gene products from the core RD1 region have been shown to be deeply implicated in this process, less is known about proteins encoded further upstream in the 5′ region of the ESX-1 cluster, such as the ESX-1 secretion-associated proteins (Esps) EspF or EspG1. Methods. To elucidate the role of EspF/G1, whose orthologs in Mycobacterium marinum and Mycobacterium smegmatis are reportedly involved in EsxA/B secretion, we constructed 3 M. tuberculosis knockout strains deleted for espF, espG1 or the segment corresponding to the combined RD1bcg-RD1mic region of bacille Calmette-Guérin (BCG) and Mycobacterium microti, which also contains espF and espG1. Results. Analysis of these strains revealed that, unlike observations with the model organisms M. smegmatis or M. marinum, disruption of espF and espG1 in M. tuberculosis did not impact the secretion and T cell recognition of EsxA/B but still caused severe attenuation. Conclusions. The separation of the 2 ESX-1-connected phenotypes (ie, EsxA/B secretion and virulence) indicates that EsxA/B secretion is not the only readout for a functional ESX-1 system and suggests that other processes involving EspF/G1 also play important roles in ESX-1-mediated pathogenicit

    Wyllieite-type Ag1.09Mn3.46(AsO4)3

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    Single crystals of wyllieite-type silver(I) manganese(II) tris­orthoarsenate(V), Ag1.09Mn3.46(AsO4)3, were grown by a solid-state reaction. The three-dimensional framework is made up from four Mn2+/Mn3+ cations surrounded octa­hedrally by O atoms. The MnO6 octa­hedra are linked through edge- and corner-sharing. Three independent AsO4 tetra­hedra are linked to the framework through common corners, delimiting channels along [100] in which two partly occupied Ag+ sites reside, one on an inversion centre and with an occupancy of 0.631 (4), the other on a general site and with an occupancy of 0.774 (3), both within distorted tetra­hedral environments. One of the Mn sites is also located on an inversion centre and is partly occupied, with an occupancy of 0.916 (5). Related compounds with alluaudite-type or rosemaryite-type structures are compared and discussed

    Contribution au développement d'un système de surveillance des structures en génie civil

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    Ce travail s’inscrit dans le cadre de la mise en place d’une stratégie de SHM (Structural Health Monitoring) dédiée à la surveillance des structures en génie civil. Il a porté, d’une part, sur l’étude des méthodes de détection et de localisation de l’endommagement du bâti existant et, d’autre part, sur l’élaboration du cahier des charges d’un capteur « intégré » capable de délivrer des informations par transmission compacte des données pour les communiquer à une chaîne SHM. Des études numériques et expérimentales ont été réalisées dans cet objectif. L’état de l’art a clairement mis en évidence plusieurs points faibles des méthodes de détection et de localisation d’endommagements usuelles comme, par exemple, le manque de précision et/ou la complexité de mise en place. On observe aussi que la sensibilité de ces méthodes par rapport à plusieurs paramètres, essentiellement la direction de mesure, le positionnement des capteurs et la sévérité des endommagements, ne permet pas à ce jour de dresser un diagnostic précis de l’état de santé des structures. Pour répondre au cahier des charges d’une chaîne SHM, un Algorithme de Détection et de Localisation (ADL) a été élaboré. Cet algorithme fait appel à des méthodes utilisant les paramètres modaux, essentiellement les fréquences propres et les déformées modales. Leurs mises en œuvre séquentielles et itératives, judicieusement structurées et pilotées,a permis de répondre aux objectifs fixés. Les paramètres modaux requis sont identifiés à l’aide des techniques d’Analyse Modale Opérationnelle (AMO) et à partir de la réponse en accélérations des structures. Deux algorithmes d’AMO ont été utilisés pour leur efficacité et pour leur aptitude à l’automatisation: la méthode stochastique par sous ensemble (SSI), et la méthode de décomposition dans le domaine fréquentiel (FDD). En fusionnant les algorithmes d’AMO avec l’ADL, une chaîne complète de surveillance a été créée. La validation des algorithmes et de la chaîne de surveillance s’est faite à plusieurs niveaux. Tout d’abord, basés sur la théorie des éléments finis, des modèles numériques de la tour de l'Ophite et du pont canadien de la Rivière aux-Mulets ont permis d'évaluer l'ADL. Ces modèles sont endommagés par des signaux sismiques et fournissent les données accélérométriques, données d’entrée du logiciel que nous avons développé. Les résultats obtenus sont tout à fait satisfaisants voire meilleurs que ceux issus des méthodes usuelles. Dans un second temps, nous avons traité des données expérimentales «réelles », issues des mesures accélérométriques sur la tour de l’Ophite. La confrontation entre les résultats d’identification des fréquences propres et des déformées modales issus des algorithmes d’AMO et ceux reportés par la bibliographie, a révélé l’efficacité des algorithmes développés.Enfin, une maquette d’un bâtiment à échelle réduite a également été élaborée et instrumentée.L’application de la chaine de surveillance a permis, d’une part, de détecter et localiser l’endommagement introduit dans la structure et, d’autre part, de mettre en évidence l’intérêt de la surveillance automatique. Finalement, une étude a été menée dans le but de réduire la quantité d’informations enregistrées sur les structures et de faciliter le transfert des données servant comme entrées de la chaîne de surveillance. Les résultats de ces études ont contribué à la spécification d’un nouveau système de surveillanc

    Systemic sclerosis in a patient with pityriasis rubra pilaris

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    Pityriasis rubra pilaris (PRP) is a rare, chronic erythematous squamous disorder of unknown etiology. It has been found in association with several autoimmune diseases, including thyroiditis, myositis, myasthenia gravis and vitiligo. Herein we report a case of systemic sclerosis in a patient with classic adult pityriasis rubra pilaris. A 38 year old woman with classic adult type 1 pityriasis rubra pilaris (PRP) developed progressive skin thickening of the trunk, face, upper and lower extremities after 2 years of PRP treatment with topical emollients and steroids. Clinical examination and immunological findings were consistent with SSc. Co-existence of these two rare conditions is documented for the first time

    The Ubiquitous Role of New Social Media Channels and Innovative Mobile Services: Are Consumers Ready?

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    Over the past decade, the world of social media is evolving at warp speed. In light of this rapid evolution, investigating social media users behaviour is top of the agenda for many managers and marketing researchers today (Kaplanand Haenlein, 2010). Indeed, still there are several areas in which we believe social media channels such as social networking, e-commerce, s-commerce, and blogs will make the most trivial evolution in years to come. Given the background provided about social media platforms adoption and strategic usage, there are some interesting and relevant topics that are particularly relevant in research on consumer behaviour towards these geo-information platforms and await further empirical exploration. Firstly, considering the cross-cultural aspects in studying the LBSN adoption on mobile phones, in a relationship social context, is a key driver of the growth and success of mobile LBSN and is even crucial to telecommunication operators to implement these services. Secondly, recently s-commerce is considered as a new form of social media that has arisen which due to its social features seem to have a great power of influence on consumers’ purchasing decision-making process. The marketing area has thus evolved from a time where marketers had the power of influence to today where consumers have a greater power of influence on their peers (Jaffe, 2010). Finally, with the advent of 4G mobile devices and the mobile location based advertising, consumers’ preferences can be pre-identified and advertising content can therefore be delivered to consumers at the right time and at the right place with the right message (Chen and Hsieh, 2012). Therefore, it becomes necessary and reasonable to enhance our understanding about the role of mobile advertising in mediating consumers shopping experience, since we begin to find ourselves bringing our mobile devices everywhere we go
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