166 research outputs found
Audiovisual data fusion for successive speakers tracking
International audienceIn this paper, a human speaker tracking method on audio and video data is presented. It is applied to con- versation tracking with a robot. Audiovisual data fusion is performed in a two-steps process. Detection is performed independently on each modality: face detection based on skin color on video data and sound source localization based on the time delay of arrival on audio data. The results of those detection processes are then fused thanks to an adaptation of bayesian filter to detect the speaker. The robot is able to detect the face of the talking person and to detect a new speaker in a conversation
Formation of six-membered palladacycles from phenanthroline Pd(II) bisacetate precursors and phenylisocyanate
Synthesis and characterization of 5a-d. CCDC-221834 contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via: www.ccdc.cam.ac.uk/data_request.cif.International audiencePhenylisocyanate reacts with palladium(II) bis-acetate phenanthroline complexes to give six-membered palladacycles in nearly quantitative yields. In this new reaction, the acetate ligands act as decarbonylating agents toward the isocyanate functionality by possibly forming the isolated palladacycles via an intramolecular rearrangement
An Evidential Filter for Indoor Navigation of a Mobile Robot in Dynamic Environment
International audienceRobots are destined to live with humans and perform tasks for them. In order to do that, an adapted representation of the world including human detection is required. Evidential grids enable the robot to handle partial information and ignorance, which can be useful in various situations. This paper deals with an audiovisual perception scheme of a robot in indoor environment (apartment, house..). As the robot moves, it must take into account its environment and the humans in presence. This article presents the key-stages of the multimodal fusion: an evidential grid is built from each modality using a modified Dempster combination, and a temporal fusion is made using an evidential filter based on an adapted version of the generalized bayesian theorem. This enables the robot to keep track of the state of its environment. A decision can then be made on the next move of the robot depending on the robot's mission and the extracted information. The system is tested on a simulated environment under realistic conditions
Proper Orthogonal Decomposition Analysis and Modelling of the wake deviation behind a squareback Ahmed body
We investigate numerically the 3-D flow around a squareback Ahmed body at Reynolds number Re = 104. Proper Orthogonal Decomposition (POD) is applied to a symmetry-augmented database in order to describe and model the flow dynamics. Comparison with experiments at a higher Reynolds number in a plane section of the near-wake at mid-height shows that the simulation captures several features of the experimental flow, in particular the antisymmetric quasi-steady deviation mode. 3-D POD analysis allows us to classify the different physical processes in terms of mode contribution to the kinetic energy over the entire domain. It is found that the dominant fluctuating mode on the entire domain corresponds to the 3-D quasi-steady wake deviation, and that its amplitude is well estimated from 2-D near-wake data. The next most energetic flow fluctuations consist of vortex shedding and bubble pumping mechanisms. It is found that the amplitude of the deviation is negatively correlated with the intensity of the vortex shedding in the spanwise direction and the suction drag coefficient. Finally, we find that despite the slow convergence of the decomposition, a POD-based low-dimensional model reproduces the dynamics of the wake deviation observed experimentally, as well as the main characteristics of the global modes identified in the simulation
Learning Constrained Edit State Machines
International audienceLearning the parameters of the edit distance has been increasingly studied during the past few years to improve the assessment of similarities between structured data, such as strings, trees or graphs. Often based on the optimization of the likelihood of pairs of data, the learned models usually take the form of probabilistic state machines, such as pair-Hidden Markov Models (pair-HMM), stochastic transducers, or probabilistic deterministic automata. Although the use of such models has lead to significant improvements of edit distance-based classification tasks, a new challenge has appeared on the horizon: How integrating background knowledge during the learning process? This is the subject matter of this paper in the case of (input,output) pairs of strings. We present a generalization of the pair-HMM in the form of a constrained state machine, where a transition between two states is driven by constraints fulfilled on the input string. Experimental results are provided on a task in molecular biology, aiming to detect transcription factor binding sites
Photoactive/passive molecular glass blends : an efficient strategy to optimize azomaterials for surface relief grating inscription
: Irradiation of azomaterials causes various photophysical and photomechanical effects that can be exploited
for the preparation of functional materials such as surface relief gratings (SRGs). Herein, we develop and apply an efficient
strategy to optimize the SRG inscription process by decoupling, for the first time, the important effects of the azo content
and glass transition temperature (Tg). We prepare blends of a photoactive molecular glass functionalized with the azo Dis‐
perse Red 1 (gDR1) with a series of analogous photopassive molecular glasses. Blends with 10 and 40 mol% of gDR1 are
completely miscible, present very similar optical properties, and cover a wide range of Tg from below to well above ambient
temperature. SRG inscription experiments show that the diffraction efficiency (DE), residual DE and initial inscription rate
reach a maximum when Tg is 25 to 40 °C above ambient temperature for low to high azo content, respectively. Indeed, for
a fixed 40 mol% azo content, choosing the optimal Tg enables doubling the SRG inscription rate and increasing DE sixfold.
Moreover, a higher azo content enables higher DE for a similar Tg. Spectroscopy measurements indicate that the photo‐
orientation of DR1 and its thermal stability are maximal with Tg around 70 °C, independent of the azo content. We conclude
that the SRG potential of azomaterials depends on their capability to photo‐orient but that the matrix rigidity eventually
limits the inscription kinetics, leading to an optimal Tg that depends on the azo content. This study exposes clear material
design guidelines to optimize the SRG inscription process and the photoactivity of azomaterials
Transarterial treatment approaches of hepatocellular carcinoma
À côté de la chimioembolisation intra-artérielle hépatique régionale,
différentes approches de traitement endovasculaire du
carcinome hépatocellulaire sont en cours d’évaluation : chimioembolisation
hypersélective ; chimioembolisation par microsphères
chargeables ; radioembolisation. Cet article vise à décrire
les différentes techniques et à préciser la place de la chimioembolisation
dans la stratégie thérapeutique du carcinome
hépatocellulaire ainsi que les principaux champs d’investigation
clinique pour les techniques plus innovantes.Transarterial regional chemoembolisation is one of the therapeutic
options in the palliative treatment of advanced hepatocellular
carcinoma. Several other transarterial approaches are under
investigation including selective transarterial chemoembolization,
embolization with drug-eluting beads, and radioembolisation. The
aim of this article is to describe the technical aspects of these
techniques and to indicate their indication and/or clinical fields of
investigation
On the relationship between the base pressure and the velocity in the near-wake of an Ahmed body
We investigate the near-wake flow of an Ahmed body which is characterized by switches between two asymmetric states that are mirrors of each other in the spanwise direction. The work focuses on the relationship between the base pressure distribution and the near-wake velocity field. Using direct numerical simulation obtained at a Reynolds number of 10000 based on incoming velocity and body height as well as Bonnavion and Cadot's experiment (Bonnavion et al. 2018), we perform Proper Orthogonal Decomposition (POD) of the base pressure field. The signature of the switches is given by the amplitude of the most energetic, antisymmetric POD mode. However switches are also characterized by a global base suction decrease, as well as deformations in both vertical and lateral directions, which all correspond to large-scale symmetric modes. Most of the base suction reduction is due to the two most energetic symmetric modes. Using the linear stochastic estimation technique of Podvin et al. 2018, we show that the large scales of the near-wake velocity field can be recovered to some extent from the base pressure modes. Conversely, it is found that the dominant pressure modes and the base suction fluctuation can be well estimated from the POD velocity modes of the near-wake
Relationship between the base pressure and the velocity in the near-wake of an Ahmed body
We investigate the near-wake flow of an Ahmed body which is characterized by
switches between two asymmetric states that are mirrors of each other in the
spanwise direction. The work focuses on the relationship between the base
pressure distribution and the near-wake velocity field. Using direct numerical
simulation obtained at a Reynolds number of 10000 based on incoming velocity
and body height as well as Bonnavion and Cadot's experiment (Bonnavion et al.
2018), we perform Proper Orthogonal Decomposition (POD) of the base pressure
field. The signature of the switches is given by the amplitude of the most
energetic, antisymmetric POD mode. However switches are also characterized by a
global base suction decrease, as well as deformations in both vertical and
lateral directions, which all correspond to large-scale symmetric modes. Most
of the base suction reduction is due to the two most energetic symmetric modes.
Using the linear stochastic estimation technique of Podvin et al. 2018, we show
that the large scales of the near-wake velocity field can be recovered to some
extent from the base pressure modes. Conversely, it is found that the dominant
pressure modes and the base suction fluctuation can be well estimated from the
POD velocity modes of the near-wake.Comment: 34 pages, 12 figure
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