Utilisation de l'information photométrique pour la sélection des hyperparamètres en recalage géométrique d'images

National audienceCet article traite du recalage paramétrique d'images à partir de correspondances de points en environnement déformable. Dans ce problème, il est essentiel de déterminer des valeurs correctes pour les hyperparamètres tels que le nombre de points de contrôle du modèle de déformation, un paramètre de régularisation ou l'échelle d'un M-estimateur. Cela est souvent réalisé à la main par tâtonnement ou en optimisant un critère générique comme la validation croisée. Dans cet article, nous proposons un nouveau critère pour sélectionner différents hyperparamètres en combinant les avantages de l'approche géométrique et de l'approche photométrique au recalage d'images. Plus précisément, nous proposons de considérer les correspondances de points comme un jeu d'entrainement et la photométrie comme un jeu d'essai. L'approche proposée est robuste dans la mesure où elle résiste à la fois aux correspondances de points erronées et aux défauts des images comme les occultations ou les spécularités

The Roman Catholic Communities of Cloyne Diocese, Co. Cork, 1700 -1830

The aim of this thesis is to present an understanding of the complexity of some of the responses and reactions of different eighteenth and early nineteenth-century Roman Catholic parish congregations and their clergy from Cloyne Diocese, Co. Cork to their changing and often challenging circumstances. A rich repository of source materials such as the visitation books of Roman Catholic Bishops, clerical correspondence and other sources has been relied upon. A scalar analytical framework ranging from the personal, to the intergroup, to the international is utilised. Key factors in the re-emergence of this Church and its communities such as historical and cultural awareness, the interdependent efforts of different social groups and the fact that Cloyne was never a bounded entity in the sense that it was separated from the wider Catholic world and/or other external influences are identified. While some of Cloyne’s Catholics may have tended to view themselves as a “separate and injured community” (Dickson, 2005, p. 264) on account of the varied impacts of colonialism, that this may also have occurred as a consequence of social class changes cannot be ignored. That the successful social re-emergence of some Catholics and their associated communities may have come about at the marginalisation of others is factored into this analysis. Consequently, this study presents an exploration of the interplay between a spectrum of different personal, religious, cultural, geographical, socio-economic and other worlds, each of varying depths and complexities, with some overlapping, blending and intersecting, and others avoiding and/or in conflict with each other and/or with other worlds

Intérêt et motivation des jeunes pour les sciences

Conférence présentée lors du colloque « Journée de la recherche sur la motivation au collégial » Acfas, Montréal, 10 mai 201

New material of Laophis crotaloides, an enigmatic giant snake from Greece, with an overview of the largest fossil European vipers

Laophis crotaloides was described by Richard Owen as a new and very large fossil viperid snake species from Greece. The type material is apparently lost and the taxon was mostly neglected for more than a century. We here describe a new partial viperid vertebra, collected from the same locality and of equivalent size to the type material. This vertebra indicates that at least one of the three morphological characters that could be used to diagnose L. crotaloides is probably an artifact of the lithographer who prepared the illustration supporting the original description. A revised diagnosis of L. crotaloides is provided on the basis of the new specimen. Despite the fragmentary nature of the new vertebra, it confirms the validity of L. crotaloides, although its exact relationships within Viperidae remain unknown. The new find supports the presence of a large viperid snake in the early Pliocene of northern Greece, adding further data to the diversity of giant vipers from Europe

A generic testing framework for agent-based simulation models

International audienceAgent-based modelling and simulation (ABMS) had an increasing attention during the last decade. However, the weak validation and verification of agent-based simulation models makes ABMS hard to trust. There is no comprehensive tool set for verification and validation of agent-based simulation models, which demonstrates that inaccuracies exist and/or reveals the existing errors in the model. Moreover, on the practical side, many ABMS frameworks are in use. In this sense, we designed and developed a generic testing framework for agent-based simulation models to conduct validation and verification of models. This paper presents our testing framework in detail and demonstrates its effectiveness by showing its applicability on a realistic agent-based simulation case study

Building collaboration in multi-agent systems using reinforcement learning

© Springer Nature Switzerland AG 2018. This paper presents a proof-of concept study for demonstrating the viability of building collaboration among multiple agents through standard Q learning algorithm embedded in particle swarm optimisation. Collaboration is formulated to be achieved among the agents via competition, where the agents are expected to balance their action in such a way that none of them drifts away of the team and none intervene any fellow neighbours territory, either. Particles are devised with Q learning for self training to learn how to act as members of a swarm and how to produce collaborative/collective behaviours. The produced experimental results are supportive to the proposed idea suggesting that a substantive collaboration can be build via proposed learning algorithm