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Dominant point detection based on discrete curve structure and applications
No full textInternational audienceIn this paper, we investigate the problem of dominant point detection on digital curves which consists in nding points with local maximum curvature. Thanks to previous studies of the decomposition of curves into sequence of discrete structures [1, 2, 3], namely maximal blurred segments of width ν [4], an initial algorithm has been proposed in [5] to detect dominant points. However, an heuristic strategy is used to identify the dominant points. We now propose a modied algorithm without heuristics but a simple measure of angle. In addition, two applications are as well presented: (1) polygonal simplication to reduce the number of detected dominant points by associating a weight to each of them, and (2) classication using the polygon issued from the reduced dominant points. The experimental results demonstrate the eciency and robustness of the proposed method
Communication Functions for a Gate Driver Under High Voltage and High dv/dt
No full textInternational audienceThe control of MOSFET or IGBT transistors is carried out by a dedicated circuit called « driver » which is located as closeas possible to the power module. It transmits switch-on and switch-off orders coming from the control unit and ensures the integrity ofthe component through safety functions. It also provides a galvanic insulation essential to ensure the effective functioning of the systemand the users’ safety. Switching times of SiC MOSFET are faster than Si IGBT and SiC MOSFET can also work under a stronger DCvoltage. This involves the presence of higher dv/dt in the converter. In this paper, a communication function is studied with the aim ofbeing integrated into the new generations of drivers for SiC MOSFET. The interest of the implementation of a communication systemin a driver is presented. Currently available solutions on the market to provide insulation to communication channels are debated. Thetheoretical development of a solution called « CAN-ISO » is detailed and experimental results under high voltage and high dv/dt,respectively equal to 2 kV and 125 kV/μs, are presented
An open-source quadrature-based population balance solver for OpenFOAM
No full textInternational audienceThe extended quadrature method of moments (EQMOM) for the solution of population balance equations (PBE) is implemented in the open-source computational fluid dynamic (CFD) toolbox OpenFOAM as part of the Open-QBMM project. The moment inversion procedure was designed (Nguyen et al., 2016) to maximize the number of conserved moments in the transported moment set. The algorithm is implemented in a general structure to allow the addition of other kernel density functions defined on R + , and arbitrary kernels to describe physical phenomena involved in the evolution of the number density function. The implementation is verified with a set of zero-dimensional cases involving aggregation and breakage problems. Comparison to the rigorous solution of the PBE provides validation for these cases. The coupling of the EQMOM procedure with a CFD solver to address aggre-gation and breakage problems of non-inertial particles is validated against experimental measurements in a Taylor-Couette reactor from literature
Expected Length of the Voronoi Path in a High Dimensional Poisson-Delaunay Triangulation
No full textInternational audienceLet X be a d dimensional Poisson point process. We prove that the expected length of the Voronoi path between two points at distance 1 in the Delaunay triangulation associated with X is sqrt(2d/π) + O(d^(−1/2) when d → ∞. In any dimension, we also provide a precise interval containing the actual value; in 3D the expected length is between 1.4977 and 1.50007
MODULE FOR CONTROLLING THE INTERNAL ENERGY OF A CONVERTER
No full textThe invention relates to a multilevel modular converter (10) including a control module (12) for regulating the internal energy stored in the capacitors of the submodules of a half arm of the converter, the control module being capable of keeping the internal energy below an upper limit and/or above a lower limit, by using parameters measured on the DC electrical power supply network (110) and on the AC electrical power supply network (120) as well as operating power setpoints of the converter
Fast models dedicated to simulation of eddy current thermography.
No full textInternational audienceThis communication presents the first development aiming at efficiently simulating configurations of eddy current thermography for nondestructive evaluation. The numerical method proposed here is based on the Finite Integration Technique for both electromagnetic and thermal problems. Simulation results obtained using two different materials, steel and aluminum, are compared and discussed with respect to the presence of a flaw affecting the piece under test
Compact Folded Fresnel Zone Plate Lens Antenna for 5G Point-to-Point Communications
No full textInternational audienceThis paper presents the design and simulations of a new single polarized compact folded Fresnel zone plate lens antenna for 5G millimeter-wave point-to-point communications backhauling links in V-band. This antenna has two benefits: the compactness of folded reflector structures, made of a trans-reflector and twist-reflector, and the simplicity of Fresnel zone plate lenses. The idea of the folded structure is to triple the electrical path while maintaining the same physical distance, resulting in a compact, high directive, broadband, steerable and low cost antenna. A peak gain of 32.2 dBi is obtained at 60 GHz, with almost flat gain from 57 to 66 GHz, with a beam width of 2.7°, compliant with ETSI V-band class 2 standard
Machine Learning Techniques to Predict Sensitive Patterns to Fault Attack in the Java Card Application
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M/G/1 queue with event-dependent arrival rates
No full textInternational audienceMotivated by experiments on customers' behavior in service systems, we consider a queueing model with event-dependent arrival rates. Customers' arrival rates depend on the last event which may either be a service departure or an arrival. We derive explicitly the performance measures and analyze the impact of the event-dependency. In particular, we show that this queueing model, in which a service completion generates a higher arrival rate than an arrival, performs better than a system in which customers are insensitive to the last event. Moreover, contrary to the M/G/1 queue, we show that the coefficient of variation of the service does not necessarily deteriorate the system performance. Next, we show that this queueing model may be the result of customer's strategic behavior when only the last event is known. Finally, we investigate the historical admission control problem. We show that under certain conditions a determin-istic policy with two thresholds may be optimal. This new policy is easy to implement and provides an improvement compared to the classical one-threshold policy