Learning search behaviour from humans

A frequent method for taking into account the partially observable nature of an environment in which robots interact lies in formulating the problem domain as a Partially Observable Markov Decision Process (POMDP). By having humans demonstrate how to act in this partially observable context we can leverage their prior knowledge, experience and intuition, which is difficult to encode directly in a controller, to solve a task formulated as a POMDP. In this work we learn search behaviours from human demonstrators and transfer this knowledge to a robot in a context where no visual information is available. The task consists of finding a block on a table. This is a non-trivial problem since no visual information is available and as a result, the belief of the demonstrator’s state (position in the environment) has to be inferred. We show that by representing the belief of the human’s position in the environment by a particle filter (PF) and learning a mapping from this belief to their end-effector velocities with a Gaussian Mixture Model (GMM), we model the human’s search process. We compare the different types of search behaviour demonstrated by the humans to that of our learned model, to validate that the search process has been successfully modelled. We then contrast the performance of this human-inspired search model to a greedy controller and show that (similarly to humans) the learned controller minimises uncertainty, hence demonstrating more robustness in the face of false belief

A fourfold coordinated point defect in silicon

Due to their technological importance, point defects in silicon are among the best studied physical systems. The experimental examination of point defects buried in bulk is difficult and evidence for the various defects usually indirect. Simulations of defects in silicon have been performed at various levels of sophistication ranging from fast force fields to accurate density functional calculations. The generally accepted viewpoint from all these studies is that vacancies and self interstitials are the basic point defects in silicon. We challenge this point of view by presenting density functional calculations that show that there is a new fourfold coordinated point defect in silicon that is lower in energy

Patrimoines de la Seconde Guerre mondiale en Normandie

Ce projet collectif de recherche lancé en 2015 vise à inventorier dans les départements du Calvados, de la Manche et de l’Orne tous les éléments du dernier conflit qui sont conservés, disparus ou enfouis, et à en restituer la cohérence historique. Il vise particulièrement à étudier les différents éléments dans l’histoire du conflit et leur place dans les dispositifs militaires. Il porte donc aussi bien sur les vestiges liés à l’Occupation que sur les vestiges alliés ou les traces et aménageme..

Vestiges de la Seconde Guerre mondiale en Basse-Normandie

Ce programme collectif de recherche vise à inventorier de manière exhaustive les éléments conservés, disparus ou enfouis, formant des ensembles cohérents, sans se limiter aux seules élévations, et à appréhender les différents éléments dans l’histoire du conflit et leur place dans le dispositif défensif. Il s’appuie à la fois sur des études documentaires, des recherches de terrain ainsi que sur une base de données couplée à un SIG. Ce projet répond à un besoin urgent de gestion de ce patrimoin..

Vestiges de la Seconde Guerre mondiale en Basse-Normandie

Pour rappel, ce programme collectif de recherche vise à inventorier de manière exhaustive les éléments conservés, disparus ou enfouis, formant des ensembles cohérents, sans se limiter aux seules élévations, et à appréhender les différents éléments dans l’histoire du conflit et leur place dans le dispositif défensif. Il s’appuie à la fois sur des études documentaires, des recherches de terrain ainsi qu’une base de données couplée à un SIG. Ce projet répond à un besoin urgent de gestion de ce p..

Mapping Robots to Therapy and Educational Objectives for Children with Autism Spectrum Disorder

The aim of this study was to increase knowledge on therapy and educational objectives professionals work on with children with autism spectrum disorder (ASD) and to identify corresponding state of the art robots. Focus group sessions (n = 9) with ASD professionals (n = 53) from nine organisations were carried out to create an objectives overview, followed by a systematic literature study to identify state of the art robots matching these objectives. Professionals identified many ASD objectives (n = 74) in 9 different domains. State of the art robots addressed 24 of these objectives in 8 domains. Robots can potentially be applied to a large scope of objectives for children with ASD. This objectives overview functions as a base to guide development of robot interventions for these children

Nouvelles méthodes de synthèse d'analogues de nucléosides

Ce travail porte sur la mise au point de nouvelles méthodes de synthèse d'analogues de nucléosides. Nous décrivons dans la première partie, la synthèse de la thymidine à partir du 2-désoxy-D-ribose par condensation de la thymine silylé avec le 2-désoxy-D-érythro-pentofuranosyl-trichloroatimidate.Cette synthèse est effectuée en six étapes et seulement une purification avec un rendement global de 30% et une stéréosélectivité de l'ordre de 80 %.Dans la deuxième et la troisième partie,des analogues de nucléosides munis d'un bras espaceur entre la partie glucidique et la partie hétérocyclique sont synthétisés par glycosylation de la thymine hydoxyalkilée avec l'a-D-ribose 1,3,5-tribenzoate convenablement substitué puis désoxygénation ou par glycosylation directe par des sucres non protégés tels que le glucose, le xylose ou le 2-désoxy-D-ribose sous différentes conditions expérimentales (acide de Lewis,solvant,température).Tous les composés obtenus sant caractérisés par différentes méthode spectroscopiques.L'étude détaillée des sepctres RMN 1H et 13C a permis les différents épimères obtenus.LIMOGES-BU Sciences (870852109) / SudocSudocFranceF

Selective trifluoromethylthiolation of heteroaromatic sp2 C-H bonds with the 2nd generation of trifluoromethanesulfenamide reagent

International audienceBy applying a well-established protocol of selective deprotonation of heteroarenes, the selective trifluoromethylthiolation of various heteroaromatic compounds has been performed, by using the 2nd generation of trifluoromethanesulfenamide reagent. With such strategy, functionalized heteroarenes could be synthesized as potential trifluoromethylthiolated building-blocks

Selective trifluoromethylthiolation of heteroaromatic sp2 C-H bonds with the 2nd generation of trifluoromethanesulfenamide reagent

International audienceBy applying a well-established protocol of selective deprotonation of heteroarenes, the selective trifluoromethylthiolation of various heteroaromatic compounds has been performed, by using the 2nd generation of trifluoromethanesulfenamide reagent. With such strategy, functionalized heteroarenes could be synthesized as potential trifluoromethylthiolated building-blocks

Electrophilic trifluoromethylthiolation of carbonyl compounds

International audienceA general method for the α-trifluoromethylthiolation of carbonyl compounds, without prefunctionalization, has been developed. Aldehydes, ketones, esters, amides, keto-esters, alkaloids, and steroids have been trifluoromethylthiolated with good yields. This work, proposing a new reagent for electrophilic trifluoromethylthiolation, provides a route towards the original synthesis of various trifluoromethylthiolated molecules for further applications