Nicolas Chavannes

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The objective of this study was to develop a numerical solver to calculate the magneto-hydrodynamic (MHD) signal produced by a moving conductive liquid, i.e. blood flow in the great vessels of the heart, in a static magnetic field. We believe that this MHD signal is able to non-invasively characterize cardiac blood flow in order to supplement the present(More)
This study analyzes the exposure of pregnant women and their fetuses in three different gestational stages to electromagnetic radiation in the radio frequency range in the near- and the far-field using numerical modeling. For far-field exposure, the power density at which the basic restriction for the whole body SAR is reached is calculated for both the(More)
A new human head phantom has been proposed by CENELEC/IEEE, based on a large scale anthropometric survey. This phantom is compared to a homogeneous Generic Head Phantom and three high resolution anatomical head models with respect to specific absorption rate (SAR) assessment. The head phantoms are exposed to the radiation of a generic mobile phone (GMP)(More)
In this paper, we describe a specifically designed patch antenna that can be used as the basis antenna element of a clinical phased-array head and neck hyperthermia applicator. Using electromagnetic simulations we optimized the dimensions of a probe-fed patch antenna design for operation at 433 MHz. By several optimization steps we could converge to a(More)
The modeling of thermal effects, often based on the Pennes Bioheat Equation, is becoming increasingly popular. The FDTD technique commonly used in this context suffers considerably from staircasing errors at boundaries. A new conformal technique is proposed that can easily be integrated into existing implementations without requiring a special update(More)
This paper presents preliminary evaluation of the hybrid parallelization of the Finite-Difference Time-Domain (FDTD) method based on Open Computing Language (OpenCL) and the Message Passing Interface (MPI). Due to the portability of OpenCL, developed code targets not only distributed shared memory computer clusters based on multi-core central processing(More)
In this paper we evaluate the usability and performance of Open Computing Language (OpenCL) targeted for implementation of the Finite-Difference Time-Domain (FDTD) method. The simulation speed was compared to implementations based on alternative techniques of parallel processor programming. Moreover, the portability of OpenCL FDTD code between modern(More)
1. Introduction Simulations have become an integral part of a product design workflow, as devices are becoming more complex and development cycles are shrinking to be more competitive and meet market demand. In the last two decades, the capabilities of electromagnetic simulation techniques have vastly expanded to simulate increasingly more realistic and(More)
The most successfully used technique in electromagnetic (EM) computations is the Finite-Difference Time-Domain method (FDTD, Yee 1966). However, a well known deficiency is that the staircased meshing can lead to inaccuracies in the geometrical discretization of complex models. Conformal meshing and locally (near material interfaces) modified Yee update(More)
For quality assurance of hyperthermia treatment planning systems, quantitative validation of the electromagnetic model of an applicator is essential. The objective of this study was to validate a finite-difference time-domain (FDTD) model implementation of the Lucite cone applicator (LCA) for superficial hyperthermia. The validation involved (i) the(More)