Reach Set Approximation through Decomposition with Low-dimensional Sets and High-dimensional Matrices

Approximating the set of reachable states of a dynamical system is an algorithmic yet mathematically rigorous way to reason about its safety. Although progress has been made in the development of efficient algorithms for affine dynamical systems, available algorithms still lack scalability to ensure their wide adoption in the industrial setting. While modern linear algebra packages are efficient for matrices with tens of thousands of dimensions, set-based image computations are limited to a few hundred. We propose to decompose reach set computations such that set operations are performed in low dimensions, while matrix operations like exponentiation are carried out in the full dimension. Our method is applicable both in dense- and discrete-time settings. For a set of standard benchmarks, it shows a speed-up of up to two orders of magnitude compared to the respective state-of-the art tools, with only modest losses in accuracy. For the dense-time case, we show an experiment with more than 10.000 variables, roughly two orders of magnitude higher than possible with previous approaches

Considerations on the Relevance of Cerebral Fusiform Aneurysms Observed During HIV Infection

International audienceHuman immunodeficiency virus (HIV)-associated ectatic cerebral vasculitis (HIV-AECV) is a rare form of vasculitis with diffuse fusiform aneurysms. Its pathophysiology remains poorly understood. Although extensively described in children, it is still incompletely studied in adults. Our objective was to present five adult cases with emphasis on imaging findings and long-term evolution. From 2006 to 2014, we included 5 HIV-infected patients presenting with fusiform cerebral aneurysms. Vessels abnormalities were assessed with brain computed tomography (CT) angiography, magnetic resonance angiography (MRA) and/or digital subtraction angiography (DSA). All patients had MR assessment of the brain. Clinical and biological data were analyzed. Fusiform aneurysms of carotid terminations extending to middle and anterior cerebral arteries were bilateral in three patients and unilateral in one. More distal fusiform aneurysms were observed in four patients and saccular aneurysms in two patients, two patients suffered from ischemic lesions while none experienced hemorrhage. Unlike recent reviews, our study underlines the low hemorrhagic potential of HIV-AECV and long-term follow-up suggests a monophasic evolution under antiretroviral medication

Surface enhanced infrared absorption (SEIRA) spectroscopy using gold nanoparticles on As2S3 glass

International audienceThe development of infrared sensing platform requires adapted materials. In this work, we used sputtered gold nanoparticles on a chalcogenide glass to demonstrate that these infrared materials can be used as substrate for surface enhanced infrared absorption (SEIRA) spectroscopy. The sputtering parameters were optimized to get the highest possible enhancement. To assess it, a self-assembled monolayer of 4-nitrothiophenol was used. These preliminary results are promising and pave the way for various configurations of waveguide for integrated optical components

Romeo2 Project: Humanoid Robot Assistant and Companion for Everyday Life: I. Situation Assessment for Social Intelligence

International audienceFor a socially intelligent robot, different levels of situation as-sessment are required, ranging from basic processing of sensor input to high-level analysis of semantics and intention. However, the attempt to combine them all prompts new research challenges and the need of a co-herent framework and architecture. This paper presents the situation assessment aspect of Romeo2, a unique project aiming to bring multi-modal and multi-layered perception on a single system and targeting for a unified theoretical and functional frame-work for a robot companion for everyday life. It also discusses some of the innovation potentials, which the combination of these various perception abilities adds into the robot's socio-cognitive capabilities

RF naprašované amorfní chalkogenidové tenké vrstvy pro povrchem zesílenou infračervenou absorpční spektroskopii

The primary objective of this study is the development of transparent thin film materials in the IR enabling strong infrared absorption of organic compounds in the vicinity of metal nanoparticles by the surface plasmon effect. For developing these optical micro-sensors, heterostructures combining gold nanoparticles and chalcogenide planar waveguides are fabricated and adequately characterized. Single As2S3 and Ge25Sb10Se65 amorphous chalcogenide thin films are prepared by radiofrequency magnetron sputtering. For the fabrication of gold nanoparticles on a chalcogenide planar waveguide, direct current sputtering is employed. Fabricated single layers or hetero-structures are characterized using various techniques to investigate the influence of deposition parameters. The nanoparticles of gold are functionalized by a self-assembled monolayer of 4-nitrothiophenol. Finally, the surface enhanced infrared absorption spectra of 4-nitrothiophenol self-assembled on fabricated Au/Ge-Sb-Se thin films hetero-structures are measured and analyzed. This optical component presents a ~24 enhancement factor for the detection of NO2 symmetric stretching vibration band of 4-nitrothiophenol at 1336 cm−1.Pro vývoj optických mikrosenzorů byly připraveny a adekvátně charakterizovány heterostruktury kombinující nanočástice zlata a chalkogenidové planární vlnovody. Amorfní chalkogenidové tenké vrstvy As2S3 a Ge25Sb10Se65 byly připraveny radiofrekvenčním magnetronovým naprašováním. Připravené vrstvy či heterostruktury jsou charakterizovány různými technikami s cílem studovat vliv depozičních podmínek. Nanočástice zlata jsou funkcionalizovány samouspořádanou monovrstvou 4-nitrothiofenolu. Byla změřena a analyzována povrchem zesílená infračervená absorpční spektra 4-nitrothiofenolu na připravených Au/Ge-Sb-Se tenkovrstvých heterostrukturách. Tato optická součást prokázala 24 násobné zesílení pro detekci symetrické valenční vibrace NO2 4-nitrothiofenolu při 1336 cm(-1)

La migration des jeunes: quelles mobilités? Quels ancrages?

Ce numéro d’Enfances Familles Générations porte sur les enjeux de la mobilité et de la migration des jeunes adultes. Les articles traitent, notamment, de la mobilité dans le cadre de la poursuite d’études, mais aussi de la construction identitaire en contexte migratoire. Un article Hors thème complète ce dossier thématique. Il aborde les changements dans la maternité en milieu populaire dans la région Nord-est du Brésil

The Mediterranean region under climate change

This book has been published by Allenvi (French National Alliance for Environmental Research) to coincide with the 22nd Conference of Parties to the United Nations Framework Convention on Climate Change (COP22) in Marrakesh. It is the outcome of work by academic researchers on both sides of the Mediterranean and provides a remarkable scientific review of the mechanisms of climate change and its impacts on the environment, the economy, health and Mediterranean societies. It will also be valuable in developing responses that draw on “scientific evidence” to address the issues of adaptation, resource conservation, solutions and risk prevention. Reflecting the full complexity of the Mediterranean environment, the book is a major scientific contribution to the climate issue, where various scientific considerations converge to break down the boundaries between disciplines