Publicaties
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Predicting the aerodynamic noise generation and propagation mechanisms in expansion chambers using an active bi-port formulation KU Leuven
In exhaust ducts, expansion chambers are commonly installed to attenuate the noise emitted by e.g. IC engines and compressors or flow noise sources, generated at flow discontinuities or irregularities inside the exhaust system upstream to the expansion chamber. The energy of this engine noise is concentrated around the harmonics of the engine firing frequency. Their contribution is dominant for low to medium engine speeds since aerodynamically ...
Comparison Between Parallel Hole and Rotating Slat Collimation: Analytical Noise Propagation Models KU Leuven
We have previously proposed a method to compare tomographic systems. It is assumed that each system acquires a tomographic scan of a certain tracer distribution in the same acquisition time. From this scan, each system is forced to reconstruct an image with a predefined spatial resolution. The system that can perform this task with the "most favorable" noise propagation is considered as the best system. The variance on pixel values or ...
Comparison between parallel hole and rotating slat collimation: analytical noise propagation models Vrije Universiteit Brussel
We have previously proposed a method to compare tomographic systems. It is assumed that each system acquires a tomographic scan of a certain tracer distribution in the same acquisition time. From this scan, each system is forced to reconstruct an image with a predefined spatial resolution. The system that can perform this task with the "most favorable" noise propagation is considered as the best system. The variance on pixel values or ...
An analysis of noise propagation in the multiscale simulation of coarse Fokker-Planck equations KU Leuven
We consider multiscale systems for which only a fine-scale model describing the evolution of individuals (atoms, molecules, bacteria, agents) is given, while we are interested in the evolution of the population density on coarse space and time scales. Typically, this evolution is described by a coarse Fokker–Planck equation. In this paper, we investigate a numerical procedure to compute the solution of this Fokker–Planck equation directly on the ...
Noise Propagation in Multipinhole SPECT Calibration KU Leuven
It has been shown previously that multipinhole single photon emission computed tomography (SPECT) calibration only requires a two-point source measurement, without knowledge of the distance between them, to uniquely determine the camera geometry. In this work, we studied how this method propagates measurement noise into errors on the estimated calibration parameters, which in turn will degrade the reconstruction image quality. Furthermore, the ...
Substrate Noise Propagation KU Leuven
3D High-Order Discontinuous Galerkin Methods for Time-Domain Simulation of Flow Noise Propagation (3D Discontinue Galerkin methoden voor simulatie in het tijdsdomein van devoortplanting van stromingsgeluid) KU Leuven
De directe aanpak voor aeroakoestiek, die de Navier-Stokesvergelijkingen oplost met een hoge resolutie en op een groot domein, is rekenintensief. Een alternatieve techniek, de hybriede aanpak, splitst de berekening in twee delen: een deel om de stroming en de geluidsopwekking te berekenen en daaropvolgend een deel om de geluidsvoortplanting te bepalen. Dit laat toe een optimale discretisatie en domeingrootte te kiezen voor elk deel afzonderlijk, ...
Ouvrir la boîte noire du travail de préparation de l’enseignant: Essai de modélisation et d’illustration autour du choix et de l’évolution d’un document support de cours. KU Leuven
Cette contribution offre un modèle théorique du choix et de l’évolution des supports de cours des enseignants et l’illustre avec six enseignants de mathématiques du secondaire en Belgique francophone. Notre proposition théorique articule le processus de genèse documentaire et l’Actor-Network Theory dans une approche qui cherche à rendre son importance à la matérialité dans les sciences de l’éducation. L’illustration de ce modèle au travers d’une ...