Accurate 3D maps from depth images and motion sensors via nonlinear Kalman filtering

This paper investigates the use of depth images as localisation sensors for 3D map building. The localisation information is derived from the 3D data thanks to the ICP (Iterative Closest Point) algorithm. The covariance of the ICP, and thus of the localization error, is analysed, and described by a Fisher Information Matrix. It is advocated this error can be much reduced if the data is fused with measurements from other motion sensors, or even with prior knowledge on the motion. The data fusion is performed by a recently introduced specific extended Kalman filter, the so-called Invariant EKF, and is directly based on the estimated covariance of the ICP. The resulting filter is very natural, and is proved to possess strong properties. Experiments with a Kinect sensor and a three-axis gyroscope prove clear improvement in the accuracy of the localization, and thus in the accuracy of the built 3D map.Comment: Submitted to IROS 2012. 8 page

Lutte contre les drogues et les conduites addictives : évaluer la mise en oeuvre des actions de prévention

Ce Policy Brief revient sur l’évaluation réalisée en 2014 - 2015 de quatre actions du plan gouvernemental interministériel de lutte contre les drogues et les conduites addictives 2013-2017. Tout en exposant les principaux enjeux et résultats, il s’agit également de soulever des questions sur la méthode et les buts d’un type précis d’évaluation : celle de la mise en œuvre de l’action publique. Si ce Policy Brief s’attarde surtout sur la « prévention par les pairs » à travers le cas des étudiants relais santé salariés et celui de la prévention de l’entrée dans le trafic de drogues, l’évaluation a également porté sur la prévention des troubles liés à l’alcoolisation materno-fœtale, et sur la campagne nationale de communication sur les Consultations Jeunes Consommateurs

Effect of interdiffusion on mechanical and thermal expansion properties at high temperature of a MCrAlY coated Ni-based superalloy

Free-standingmicrotensile specimens were extracted fromthe substrate and the interdiffusion zone of a MCrAlY coated nickel-based single-crystal superalloy. Testing of these specimens was conducted at elevated temperatures, up to 1100 °C under controlled atmosphere, to assess the tensile and thermal expansion properties of the interdiffusion zone materials. These properties were measured and found to lie between the properties of the substrate and those of the coating. The poor mechanical strength of the interdiffusion zone evidenced its non-load bearing contribution to the system for uniaxial creep loading at high temperature representative of service conditions. It was also shown that the fabrication process of MCrAlY coated nickel-based superalloy affects the mechanical properties of the system due to the presence of voids and non-adherent grit-blasting particles within the interdiffusion zone

Implication des cellules NK au cours des maladies auto-immunes

Auto-immune diseases (AID) form a broad spectrum of heterogeneous and chronic pathologies, most commonly affecting young adults. The etiopathogenesis of AID corresponds to a breakdown of the immunological tolerance: the result of complex mechanisms, implicating every component of the immune system. While adaptive immune cells has been extensively studied in this context, the role of innate immune cells, including Natural Killer (NK) cells, is much less understood. Using Systemic Lupus Erythematosus (SLE) and Antisynthetase Syndrome (ASS) as model pathologies, the main objective of this work is to demonstrate the involvement of NK cells in AID and to study the relevant mechanisms. Patients with AID showed numerous anomalies in the phenotypical and functional analysis of their NK cells, as compared to healthy controls. These differences are more pronounced in active rather than inactive patients. Moreover, the infiltration of target tissues by NK cells in ASS as well as the activation of these cells by SLE specific auto-antigens confirm the involvement of NK cells in AID. Additionally, interactions of NK cells with different immune cells, known to be involved in AID pathogenesis, seem to be the cause of the observed anomalies. These anomalies differ among both AID: NK cells from patients with SLE are immature and devoted to cytokine production, whereas those from patients with ASS have reached a highly differentiated but hypofunctional stage. Taken as a whole, these data suggest that NK cells are involved in the immuno-pathogenesis of AID. This involvement seems conditioned by the effect of different stimuli and different cellular interactions, which are distinct from one form of AID to another.Les maladies auto-immunes (MAI) correspondent à un large ensemble de pathologies cliniquement hétérogènes, affectant le plus souvent des adultes jeunes, de façon volontiers chronique. Du point de vue physiopathologique, ces maladies correspondent à la survenue d’une rupture de tolérance au soi, dont les mécanismes sont complexes et font appel à l’ensemble des acteurs du système immunitaire. Si l’implication des cellules de l’immunité adaptative est largement documentée dans ce contexte, celle des cellules appartenant à l’immunité innée, comme les cellules Natural Killer (NK) est peu étudié. A travers deux exemples de MAI systémiques, le Lupus Systémique (LS) et le Syndrome des Antisynthétases (SAS), l’objet de ce travail est de montrer l’implication des cellules NK au cours des MAI et d’étudier les mécanismes en cause.L’étude phénotypique et fonctionnelle des cellules NK chez des patients présentant une MAI révèle de nombreuses anomalies comparativement aux sujets contrôles. Ces dernières sont plus marquées chez les patients en phase active plutôt qu’en rémission. De plus, l’infiltration des tissus cibles au cours du SAS par les cellules NK d’une part, et l’activation in vitro de ces cellules par les auto-antigènes au cours du LS d’autre part, confirme l’implication des cellules NK au cours de ces deux MAI. Par ailleurs, des interactions des cellules NK avec plusieurs types cellulaires impliqués dans l’immunopathologie de ces maladies semblent conditionner les anomalies observées. Ces dernières sont différentes selon la maladie étudiée : le profil des cellules NK des patients atteints de LS étant plutôt immature et tourné vers la production de cytokines, tandis que celui des patients atteints de SAS correspond à un stade de différentiation terminal mais hypofonctionnel.L’ensemble des résultats suggère que les cellules NK participent à l’immunopathologie des MAI. Leur implication est conditionnée par l’effet de certains stimuli et certaines interactions cellulaires, qui sont de nature différente d’une MAI à l’autre

A survey of Identification and mitigation of Machine Learning algorithmic biases in Image Analysis

The problem of algorithmic bias in machine learning has gained a lot of attention in recent years due to its concrete and potentially hazardous implications in society. In much the same manner, biases can also alter modern industrial and safety-critical applications where machine learning are based on high dimensional inputs such as images. This issue has however been mostly left out of the spotlight in the machine learning literature. Contrarily to societal applications where a set of proxy variables can be provided by the common sense or by regulations to draw the attention on potential risks, industrial and safety-critical applications are most of the times sailing blind. The variables related to undesired biases can indeed be indirectly represented in the input data, or can be unknown, thus making them harder to tackle. This raises serious and well-founded concerns towards the commercial deployment of AI-based solutions, especially in a context where new regulations clearly address the issues opened by undesired biases in AI. Consequently, we propose here to make an overview of recent advances in this area, firstly by presenting how such biases can demonstrate themselves, then by exploring different ways to bring them to light, and by probing different possibilities to mitigate them. We finally present a practical remote sensing use-case of industrial Fairness

Evaluation de quatre actions du Plan gouvernemental de lutte contre les conduites addictives (2013-2017)

Dans le cadre des orientations prioritaires inscrites dans le plan Gouvernemental de lutte contre les drogues et les conduites addictives 2013-2017, la MILDECA a encouragé la recherche pluridisciplinaire sur les drogues et les conduites addictives. Le plan insistait notamment sur la nécessité de développer la recherche dite « évaluative », de préférence en lien avec le monde académique afin de disposer de travaux fiables, indépendants et utiles aux pouvoirs publics pour améliorer l’efficacité de l’action publique. Le rapport a pour objectif d’évaluer les processus de coopération et de coordination liés à la mise en œuvre de quatre actions du plan gouvernemental de lutte contre les drogues et les conduites addictives. La perspective théorique choisie s’inscrit dans le cadre d’une sociologie politique de l’action publique et d’une sociologie des organisations. L’angle méthodologique retenu a été celui d’une analyse fondée sur des matériaux qualitatifs. Cette étude contribue ainsi à la réalisation de la mesure 95 du plan d’actions 2013 – 2015. Plus précisément, Cette recherche évaluative avait notamment pour objectif de contribuer à évaluer le rôle de la MILDECA en tant qu’acteur de coordination et d’impulsion de la mise en œuvre de ces actions, et de permettre aux opérateurs de réaliser des ajustements « chemin faisant » dans la mise en œuvre des dispositifs

The ash mass load of volcanic plumes: retrievals from a new millimeter-wave radar at Stromboli and Sabancaya volcanoes

In the framework of the French Government Laboratory of Excellence ClerVolc initiative, two experiments using a new millimeter-wave radar were carried out to retrieve various physical properties of the ash plumes, especially the mass loading parameters which are critical for the modelling of ash dispersal, as well as to study the internal dynamics of the plumes and their fallout. First measurements at Stromboli in 2015 using a 95 GHz cloud radar prototype with a fixed beam pointing above the crater characterized the distribution of plume internal reflectivities, plume widths and durations at unprecedented space-time resolutions. Combining radar in situ measurements with data modelling from a disdrometer and ash sampling on the ground further allowed the retrieval of ash concentration and gradients inside the plumes, and sometimes proximal fallout. Plume maximum ash concentration range from 1 mg/m3 to about 1 g/m3. Structuration of ash concentration with variations by a factor of 3 was also found to occur inside the falling ash in correlation with variations in the sedimentation rate measured on the ground by the disdrometer. New results from radar measurements inside stronger plumes and fallout at Sabancaya volcano (Peru, May 2018) using volume scans will also be presented

Effect of water vapor on the spallation of thermal barrier coating systems during laboratory cyclic oxidation testing.

The effect of water and water vapor on the lifetime of Ni-based superalloy samples coated with a typical thermal barrier coating system—b-(Ni,Pt)Al bond coat and yttria stabilized zirconia (YSZ) top coat deposited by electron beam physical vapor deposition (EB-PVD) was studied. Samples were thermally cycled to 1,150 C and subjected to a water-drop test in order to elucidate the effect of water vapor on thermal barrier coating (TBC) spallation. It was shown that the addition of water promotes spallation of TBC samples after a given number of cycles at 1,150 C. This threshold was found to be equal to 170 cycles for the present system. Systems based on b-NiAl bond coat or on Pt-rich c/c0 bond coat were also sensitive to the water-drop test. Moreover, it was shown that water vapor in ambient air after minutes or hours at room temperature, promotes also TBC spallation once the critical number of cycles has been reached. This desktop spalling (DTS) can be prevented by locking up the cycled samples in a dry atmosphere box. These results for TBC systems confirm and document Smialek’s theory about DTS and moisture induced delayed spalling (MIDS) being the same phenomenon. Finally, the mechanisms implying hydrogen embrittlement or surface tension modifications are discussed

Ash concentration of Sabancaya volcanic plumes retrieved from a 95 GHz radar and a disdrometer

We have carried out an experiment using a 3.2 mm-wavelength scanning Doppler radar and a laser disdrometer to investigate ash plumes of Sabancaya volcano (Peru) in May 2018. Our main objectives were to retrieve the mass loading parameters (concentration, mass flux) which are critical for the modelling of ash dispersal, as well as to study the dimensions and internal dynamics of the eruptive columns, plumes and fallout. The radar and the disdrometer were respectively located at 4.5 km NNE and 4.5 km E from the vent. Multiple radar sounding configurations were tested either in fixed-pointing mode, generally close to the source, or using scans across various regions of the plumes. Particle Size Distribution, shapes and density were characterized from microphysical analyses, sieving and water pycnometry of ash samples collected on the ground. A Parsivel2 disdrometer also recorded the sizes, and settling velocities of fallout, allowing us to estimate sedimentation rates on the ground and to derive an empirical law relating calculated ash concentrations and reflectivities. Comparing the latter with reflectivities measured by the radar at unprecedented space-time resolutions (down to 12.5 m and 0.25 s) allowed us to obtain the internal mass distribution of eruptive columns, plumes, and fallout at various distances from the emission source

Educación para el desarrollo sostenible desde una visión integradora

La Educación para el Desarrollo Sostenible (EDS) no se reduce a promover y educar en relación a la temática. Implica una práctica cotidiana que se traduce en los propios entornos de aprendizaje. Desde la FCEIA, se intenta fortalecer el proceso de enseñanza aprendizaje, facilitar el desarrollo de investigaciones, realizar tareas de extensión y efectuar prestaciones de servicios vinculados a las carreras de grado y posgrado. Se pretende comprender lo que sucede en la sociedad e intervenir en ella, potenciando la capacidad de aprender a aprender. Se trata de conformar espacios disruptivos desde donde implementar prácticas metodológicas de innovación educativa para promover la gestión del conocimiento, la creatividad, las prácticas colaborativas y la búsqueda de soluciones a problemas comunes. Se genera una dialéctica teórico práctica que, desde el intercambio de experiencias, constituya fuente de enseñanza significativa aplicada a la solución de problemas reales. La gestión del conocimiento en red, potencia las capacidades y los aprendizajes, la interdisciplinariedad, la articulación inter e intra institucional y la auto transformación de la comunidad en educanda y educadora. Así, se ha logrado desarrollar e implementar estrategias pedagógicas innovadoras capaces de incorporar e instituir el enfoque integral que requiere la EDS