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See detailImprovement in non-linear guitar loudspeaker sound reproduction
Schmitz, Thomas ULg; Embrechts, Jean-Jacques ULg

in International Conference on Systems, Signals and Image Processing (2014, May)

This paper proposes a study of the accuracy of a guitar amplifier loudspeaker simulation. The simulation is based on a non-linear convolution of a signal using Volterra kernels, which are measured in ... [more ▼]

This paper proposes a study of the accuracy of a guitar amplifier loudspeaker simulation. The simulation is based on a non-linear convolution of a signal using Volterra kernels, which are measured in anechoic conditions with a sine-sweep technique. In this paper, we propose an evaluation of the method to minimise the cost in CPU load, while keeping the best performance in the sound reproduction. To assess the performance of the method, we measure errors between the simulated and real sounds. Human listening tests are moreover proposed in order to determine the minimum level of accuracy leading to unaudible differences with the real loudspeaker.. [less ▲]

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See detailPerformances of low-level audio classifiers for large-scale music similarity
Osmalsky, Julien ULg; Van Droogenbroeck, Marc ULg; Embrechts, Jean-Jacques ULg

in International Conference on Systems, Signals and Image Processing (2014, May)

This paper proposes a survey of the performances of binary classifiers based on low-level audio features, for music similarity in large-scale databases. Various low-level descriptors are used individually ... [more ▼]

This paper proposes a survey of the performances of binary classifiers based on low-level audio features, for music similarity in large-scale databases. Various low-level descriptors are used individually and then combined using several fusion schemes in a content-based audio retrieval system. We show the performances of the classifiers in terms of pruning and loss and we demonstrate that some combination schemes achieve a better performance at a minimum computational cost. [less ▲]

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See detailEVALUATION OF THE RAPID DETECTION OF ST-17 AND ST-1 GROUP B STREPTOCOCCI USING A MICROFLEX MALDI-TOF MS (BRUKER)
MEEX, Cécile ULg; SACHELI, Rosalie ULg; DESCY, Julie ULg et al

Poster (2014, May)

Objectives Clearly associated to neonatal meningitis, Group B streptococci (GBS) classified as sequence type-17 (ST-17) are defined as the “highly virulent” clone amongst GBS. The aim of this study was to ... [more ▼]

Objectives Clearly associated to neonatal meningitis, Group B streptococci (GBS) classified as sequence type-17 (ST-17) are defined as the “highly virulent” clone amongst GBS. The aim of this study was to evaluate an easy and rapid method, recently described to detect ST-17 and ST-1 GBS, based on distinguishing peak-shifts present on the protein spectrum of these 2 sequence types, using a Microflex (Bruker) matrix-assisted laser desorption/ionization time of flight mass spectrometer (MALDI-TOF MS). Methods This study was performed on 67 multi locus sequence typed (MLST) GBS originated from the Belgian and Czech National Reference Centers, including 18 ST-17 and 16 ST-1. After culture on blood agar, an ethanol/formic acid extraction was performed on each strain. Each extract was spotted once on a target plate, overlaid with 1 µl alpha-cyano-4-hydroxycinnamic acid matrix and further analysed by a Microflex MALDI-TOF MS. One spectrum per isolate was recorded, 240 laser shots being recorded for each spectrum. The spectra were further analysed using a Bruker prototype software, and 2 logarithmic values, one for ST-17 and one for ST-1, calculated from the intensities of the present and absent peaks, were obtained for each strain. If >0, this value indicated the presence of the specific sequence type. In a second step, the test was repeated on each strain with discordant result when compared with MLST. Results Compared with MLST method, the first analysis of the strains gave poor results, leading to very low sensitivities (77.8% for ST-17 and 50% for ST-1) but rather good specificities (85.7% for ST-17 and 98.0% for ST-1). After repeating the analysis on the strains with discordant result, sensitivity, 100% and 93.8%, and specificity, 87.8% and 98.0%, for ST-17 and ST-1 respectively were highly improved. Conclusion Since ST-17 and ST-1 GBS both show distinguishing peak-shifts on their protein spectrum, as described by Lartigue et al., the distinction of these 2 sequence types is now possible by MALDI-TOF MS. To our knowledge, this study is the first describing this application on a Microflex MS using a software to classify the strains. The observed results are promising but, given to the variability of the logarithmic value given by the software, the need to perform several measures on a same strain seems to be essential. After optimization of the analysis procedure, this rapid, easy and cheap method could be used to precociously detect ST-17 among GBS isolated from prenatal screenings, allowing a better follow up of the colonized mothers and a closer monitoring of their newborns. We would like to thank the Bruker Company which allowed us to evaluate the prototype software they have developed. [less ▲]

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See detailX-ray microtomography: A porosity-based thresholding method to improve soil pore network characterization?
Beckers, Eléonore ULg; Plougonven, Erwan ULg; Roisin, Christian et al

in Geoderma (2014), 219-220

X-ray microtomography, through quantification of soil structure at the microscale, could greatly facilitate the current understanding of soil hydrodynamic behaviour. However, binarisation method and ... [more ▼]

X-ray microtomography, through quantification of soil structure at the microscale, could greatly facilitate the current understanding of soil hydrodynamic behaviour. However, binarisation method and processing choices are subjective and can have a strong impact on results and conclusions. In this study, we test a new method based on the porosity detectable by X-ray microtomography, while validation is achieved through comparison of soil microtomogram information with soil physical measurements. These measurements consist of water retention and unsaturated hydraulic conductivity using two different soil populations with only structural differences. To assess the porosity-based method performances, we compare it to four other methods, namely the global method of Otsu and three recent soil-dedicated local methods. The robustness of the porosity-based method is also tested in regard to different pre-processing procedures. In this paper we demonstrate that soil segmentation through a porosity-based method is an interesting issue. Indeed, it is less demanding in terms of time and computational requirements than its alternatives, and combines robustness and performances broadly comparable with the recent local methods. [less ▲]

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See detailDesign of a reliable processing pipeline for the non-intrusive measurement of feet trajectories with lasers
Pierard, Sébastien ULg; Azrour, Samir ULg; Van Droogenbroeck, Marc ULg

in International Conference on Acoustics, Speech, and Signal Processing (ICASSP) (2014, May)

Reliable measurements of feet trajectories are needed in some applications, such as biomedical applications. This paper describes the data processing pipeline used in GAIMS, which is a non-intrusive ... [more ▼]

Reliable measurements of feet trajectories are needed in some applications, such as biomedical applications. This paper describes the data processing pipeline used in GAIMS, which is a non-intrusive system that measures feet trajectories based on multiple range laser scanners. Our processing pipeline relies on a new tracking paradigm, and it is based on two innovative algorithms: the first algorithm localizes the feet directly from the observed point cloud without any clustering, and the other algorithm identifies the feet. After reviewing the various types of noise affecting the point cloud, this paper explains the limitations of the classical processing approach and gives an overview of our new pipeline. The effectiveness of the proposed approach is established by discussing the results that have been obtained in several studies based on GAIMS. [less ▲]

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See detail« La flexicurité : une politique des idées ? Regards croisés d’acteurs institutionnels belges en 2013 »
Beuker, Laura ULg; Gérard, Julie ULg; Orianne, Jean-François ULg

Conference (2014, May)

Cette communication porte sur la traduction, en Belgique, d’une politique européenne de l’emploi – la flexicurité – par différents acteurs institutionnels. À partir d’une analyse documentaire et d’une ... [more ▼]

Cette communication porte sur la traduction, en Belgique, d’une politique européenne de l’emploi – la flexicurité – par différents acteurs institutionnels. À partir d’une analyse documentaire et d’une vingtaine d’entretiens semi-directifs, nous étudierons la manière dont ces acteurs s’approprient et interprètent la flexicurité. Nous nous appuierons principalement sur les apports récents de la sociologie de l’action publique, en particulier l’approche cognitive des politiques publiques (Surel, 2000 ; Muller et Surel, 1998) et l’européanisation des politiques d’emploi (Palier et Surel, 2007 ; 2010). Nous montrerons que cette appropriation a donné lieu, en Belgique, à une transformation de sens conféré à la sécurité, celle-ci étant dorénavant substitué à celui de la flexibilité. [less ▲]

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See detailAnalysis of transient scattering problems using a discontinuous Galerkin method: application to the shielding effectiveness of enclosures with heterogeneous walls
Boubekeur, Mohamed; Kameni, Abelin; Pichon, Lionel et al

in International Journal of Numerical Modelling: Electronic Networks, Devices and Fields (2014), 27(3), 626-635

In this paper, different formulations of Maxwell equations are combined for computing the shielding effectiveness of enclosures made from heterogeneous periodic materials. The validity of the homogenized ... [more ▼]

In this paper, different formulations of Maxwell equations are combined for computing the shielding effectiveness of enclosures made from heterogeneous periodic materials. The validity of the homogenized parameters given by Maxwell-Garnett rules in the frequency domain are tested in the time domain using a nodal discontinuous Galerkin method, which uses an interface condition based on analytical solution in the frequency domain to replace a conductive sheet. This interface condition allows to avoid meshing the thin sheet, thus reducing the computational cost. Results of scattering by composite enclosures are presented in the frequency domain thanks to a Fast Fourier Transform. [less ▲]

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See detailBiologie cellulaire. Exercices et méthodes
Thiry, Marc ULg; Racano, Sandra; Rigo, Pierre

Book published by Dunod (2014)

Cet ouvrage propose aux étudiants des premières années d’études supérieures une méthode progressive et conviviale pour comprendre et appliquer les concepts fondamentaux de la biologie cellulaire. Des ... [more ▼]

Cet ouvrage propose aux étudiants des premières années d’études supérieures une méthode progressive et conviviale pour comprendre et appliquer les concepts fondamentaux de la biologie cellulaire. Des bonus web avec des exercices d'entrainement supplémentaires complètent l'ouvrage. Cet ouvrage propose aux étudiants des premières années d’études supérieures une méthode progressive et conviviale pour comprendre et appliquer les concepts fondamentaux de la biologie cellulaire. À la suite de rappels de cours, sous forme de fiches, chaque chapitre propose des exercices de difficulté croissante pour s’évaluer : QCM, questions Vrai/Faux et exercices de synthèse. Les corrigés détaillés mettent en évidence la méthodologie. Des bonus web avec des exercices d’entraînement supplémentaires complètent l’ouvrage. [less ▲]

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See detailEntre recettes du Soi et recettes de l'Autre. Ethnographie de pratiques culinaires marocaines à Sesto San Giovanni (Milan, Italie)
Mescoli, Elsa ULg

Doctoral thesis (2014)

La thèse porte sur les processus de subjectivation d’un groupe de femmes marocaines résidant dans la ville de Sesto San Giovanni, dans le nord de l’Italie. Elsa Mescoli considère les habitudes ... [more ▼]

La thèse porte sur les processus de subjectivation d’un groupe de femmes marocaines résidant dans la ville de Sesto San Giovanni, dans le nord de l’Italie. Elsa Mescoli considère les habitudes alimentaires et les pratiques culinaires de ces femmes et de leurs familles, facteurs qui agissent dans la construction de soi à plusieurs niveau : celui intime, en contexte domestique ; celui partagé/contesté, en contexte publique. L’étude se situe au croisement entre l’anthropologie de l’alimentation, l’anthropologie de la culture matérielle et l’anthropologie des migrations. En fait, ces processus sont analysés en adoptant une perspective praxéologique, c’est-à-dire en portant l’attention sur la matérialité. La thèse met en évidence les « ingrédients » concrets de la définition de soi des femmes considérées, ainsi que de leurs rapports interpersonnels et « interculturels ». [less ▲]

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See detailMultiscale modelling of angiogenesis during normal and impaired bone regeneration
Carlier, Aurélie ULg

Doctoral thesis (2014)

Bone regeneration is, like many other healing events, a complex, well-orchestrated process involving a myriad of different cell types and regulated by countless biochemical, physical and mechanical ... [more ▼]

Bone regeneration is, like many other healing events, a complex, well-orchestrated process involving a myriad of different cell types and regulated by countless biochemical, physical and mechanical factors. But unlike other adult biological tissues, the majority of bone fractures can heal without the production of scar tissue, eventually recovering the original bone shape, size and strength. Despite bone’s remarkable healing capacity and the continuing research efforts, the impaired healing of complex orthopaedic cases is still not fully understood. This PhD work hypothesises that computational modelling can make a substantial contribution to the bone regeneration field by proposing and testing the underlying mechanisms of action as well as by designing and optimising experimental strategies in silico. In the first part of this work, an existing bioregulatory model of fracture healing is extended with an intracellular module of Dll4-Notch1 signalling in order to capture the ingrowth of new blood vessels through sprouting angiogenesis. The predictions of the new MOSAIC model are compared to experimental results and an extensive sensitivity analysis is performed on the newly introduced parameters. The potential of the MOSAIC model to investigate the influence of the molecular mechanisms on angiogenesis and consequently the bone formation process is illustrated. In the second part of this work, the MOSAIC model is further improved with a rigorous implementation of the influence of oxygen on the behaviour of skeletal cells. A comprehensive literature study is performed in order to ensure the correspondence of the oxygen ranges of the cell-specific oxygen-dependent processes with the state-of-the-art experimental knowledge. The oxygen model is corroborated with previously published experimental results. The robustness of the oxygen model with respect to the newly introduced oxygen thresholds is demonstrated by a sensitivity analysis. Some limitations and shortcomings of the oxygen model are identified together with suggestions for future work. In the last part of this work, the added value of the oxygen model is shown by applying it to three cases of impaired bone healing: the occurrence of nonunions in critical size defects, bone graft healing in a compromised environment and the impaired healing of bone fractures in NF1 patients. Not only is the oxygen model used to determine the underlying mechanisms of action, potential treatment strategies for the respective challenging orthopaedic conditions are also designed and optimised in silico. In conclusion, this PhD thesis demonstrates the potential of an integrative in vivo-in silico approach to advance our current understanding of bone regeneration as well as to design effective treatments of complex bone fractures. [less ▲]

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See detailControl of attosecond electronic dynamics in molecules
Mignolet, Benoît ULg

Doctoral thesis (2014)

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See detailDioxin Analyses. The Dogs Bark, but the Caravan Goes on...
Focant, Jean-François ULg

Scientific conference (2014, April 28)

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See detailMicrofossils’ diversity from the Proterozoic Taoudeni Basin, Mauritania
Beghin, Jérémie ULg; Javaux, Emmanuelle ULg; Houzay, Jean-Pierre et al

in European Geosciences Union General Assembly 2014 Vienna, Austria, 27 April – 02 May 2014 (abstract book) (2014, April 27)

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See detailIntroduction aux travaux de Luciano Del Pistoia : corps et psychose
Englebert, Jérôme ULg

Scientific conference (2014, April 25)

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See detailNanostructured catalysts by sol-gel process
Lambert, Stéphanie ULg; Heinrichs, Benoît ULg

Conference (2014, April 25)

Detailed reference viewed: 29 (4 ULg)
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See detailPredicting Grain Protein Content of Winter Wheat
Mansouri, Majdi ULg; Dumont, Benjamin ULg; Destain, Marie-France ULg

in ESANN 2014 Proceedings (2014, April 24)

Detailed reference viewed: 10 (1 ULg)