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See detailComparaison entre le profil vertical de la vitesse du vent observé dans les basses couches de la troposphère et celui simulé par le modèle WRF en Belgique
Doutreloup, Sébastien ULg; Fettweis, Xavier ULg; Beaumet, Julien ULg et al

in Camberlin, Pierre; Richard, Yves (Eds.) Actes du XXVIIe Colloque de l'Association Internationale de Climatologie : CLIMAT : SYSTÈME & INTERACTIONS (2014, July 02)

In the framework of FLEXIPAC project funded by the "RELIABLE" program of Walloon Region (Belgium), the Laboratory of Climatology Topoclimatology (LCT) of the University of Liège (Belgium) aims to adjust ... [more ▼]

In the framework of FLEXIPAC project funded by the "RELIABLE" program of Walloon Region (Belgium), the Laboratory of Climatology Topoclimatology (LCT) of the University of Liège (Belgium) aims to adjust the WRF regional model (v.3.4.) forced by the ERA-Interim reanalysis for Belgium. Our analysis shows that wind speeds at 100m simulated by WRF are systematically overestimated compared to wind speeds extracted from wind productions of two wind farms. In order to solve this problem, four ways are considered in this contribution. The first way is to compare the WRF model with the reanalysis data. The second way is to test the influence of the spatial resolution by running WRF with a finer resolution. The third way is to smooth WRF outputs, where in order to analyze the variability created by the model. And finally, the fourth way is to compare the WRF model with the MAR (v3.3.) regional model. This last way seems to confirm that the MAR model better simulates wind speeds at 10m and at 100m than the WRF model. [less ▲]

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See detailMICROPHYSIQUE DES NUAGES ET RAYONNEMENT SOLAIRE : COMPARAISON DES MESURES IN SITU AU MONT RIGI EN HAUTE BELGIQUE ET DES DONNÉES CLOUD PHYSICAL PROPERTIES (CPP) OBTENUES À PARTIR DES IMAGES METEOSAT-9
Beaumet, Julien ULg; Clerbaux, Nicolas; Cornet, Yves ULg et al

in Camberlin, Pierre; Richard, Yves (Eds.) Actes du XXVIIe Colloque de l'Association Internationale de Climatologie : CLIMAT : SYSTÈME & INTERACTIONS (2014, July 02)

Le rayonnement solaire global mesuré au mont Rigi a été comparé à l'épaisseur optique des nuages (COT) estimée à l'aide des données SEVIRI. Une relation logarithmique avec un coefficient de détermination ... [more ▼]

Le rayonnement solaire global mesuré au mont Rigi a été comparé à l'épaisseur optique des nuages (COT) estimée à l'aide des données SEVIRI. Une relation logarithmique avec un coefficient de détermination d'environ 0,5 a été trouvée. Ce résultat plutôt faible peut en grande partie s'expliquer par un nombre limité de cas où subsistent des erreurs de positionnement ou par des interactions plus complexes entre nébulosité et rayonnement. De plus, l'incertitude sur l'estimation de l'épaisseur optique des nuages à l'aide des données SEVIRI pour les nuages optiquement plus épais n'est pas négligeable. [less ▲]

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See detailThe X-ray Integral Field Unit (X-IFU) for Athena
Ravera, Laurent; Barret, Didier; den Herder, Jan Willem et al

in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series (2014, July 01)

Athena is designed to implement the Hot and Energetic Universe science theme selected by the European Space Agency for the second large mission of its Cosmic Vision program. The Athena science payload ... [more ▼]

Athena is designed to implement the Hot and Energetic Universe science theme selected by the European Space Agency for the second large mission of its Cosmic Vision program. The Athena science payload consists of a large aperture high angular resolution X-ray optics (2 m2 at 1 keV) and twelve meters away, two interchangeable focal plane instruments: the X-ray Integral Field Unit (X-IFU) and the Wide Field Imager. The X-IFU is a cryogenic X-ray spectrometer, based on a large array of Transition Edge Sensors (TES), offering 2:5 eV spectral resolution, with ~5" pixels, over a field of view of 50 in diameter. In this paper, we present the X-IFU detector and readout electronics principles, some elements of the current design for the focal plane assembly and the cooling chain. We describe the current performance estimates, in terms of spectral resolution, effective area, particle background rejection and count rate capability. Finally, we emphasize on the technology developments necessary to meet the demanding requirements of the X-IFU, both for the sensor, readout electronics and cooling chain. [less ▲]

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See detailAdvanced Aeroservoelastic Modeling for Horizontal axis Wind Turbines
Prasad, Chandra Shekhar ULg; Chen, Qiong-zhong; Dimitriadis, Grigorios ULg et al

in Cunha, A.; Caetano, E.; Riberio, P. (Eds.) et al Proceedings of the 9th International Conference on Structural Dynamics, EURODYN 2014 (2014, July)

This paper describes the development of a complete methodology for the unsteady aeroelastic and aeroservoelastic modeling of horizontal axis wind turbines at the design stage. The methodology is based on ... [more ▼]

This paper describes the development of a complete methodology for the unsteady aeroelastic and aeroservoelastic modeling of horizontal axis wind turbines at the design stage. The methodology is based on the implementation of unsteady aerodynamic modeling, advanced control strategies and nonlinear finite element calculations in the S4WT wind turbine design package. The aerodynamic modeling is carried out by means of the unsteady Vortex Lattice Method, including a free wake model. The complete model also includes a description of a doubly fed induction generator and its control system for variable speed operation and enhanced power output. The S4WT software features a non-linear finite element solver with multi-body dynamics capability. The complete methodology is used to perform complete aeroservoelastic simulations of a 2MW wind turbine prototype model. The interaction between the three components of the approach is carefully analyzed and presented here. [less ▲]

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See detailUpdate on investigation in IPF - Clinical presentation and epidemiology in domestic animals
Clercx, Cécile ULg

in Proceedings of the Fibrosis Across Species Consortium - Louisville - EU - 27th – 29th April 2014 (2014, July)

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See detailSmart Grid Energy Flexible Buildings through the use of Heat Pumps in the Belgian context
Georges, Emeline ULg; Masy, Gabrielle; Verhelst, Clara et al

in 3rd International High Performance Buildings Conference at Purdue (2014, July)

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See detailTassili n’Ajjer (Sahara Oriental Algérien) – Résultats préliminaires sur le Silurien-Dévonien
Djouder, Hocine ULg; Boulvain, Frédéric ULg; Da Silva, Anne-Christine ULg et al

in Journée Thématique de l’Association des Sédimentologistes Français (ASF) « Diagenèse : avancées récentes et perspectives » (2014, July)

Les gisements atypiques non-conventionnels, à roches sédimentaires faiblement perméables, ainsi que les « sources rocks » constituent une source pétrolière majeure, attirant de plus en plus l’industrie ... [more ▼]

Les gisements atypiques non-conventionnels, à roches sédimentaires faiblement perméables, ainsi que les « sources rocks » constituent une source pétrolière majeure, attirant de plus en plus l’industrie pétrolière, d’où un regain d’intérêt potentiel au sein du Bassin de Berkine. En effet, rien que les argiles radioactives (‘hot’) shales du Silurien sont à l’origine de 80 à 90% des hydrocarbures de la plaque Nord-africaine, et les argiles radioactives du Frasnien (source secondaire) avec des valeurs de TOC allant jusqu’à 14% (Lüning et al., 2000). L'objectif de la thèse s’agira dans un premier temps de l’analyse des diagraphies de forages (Berkine ‘subsurface’) conditionnée aux données de terrain (Tassili n’Ajjer sur affleurements) et de sismique réflexion. Ceci afin de réaliser la modélisation 2D et 3-D des corps réservoirs et de la roche mère, à l’aide du logiciel Petrel©. Et au final, la cartographie des unités de la série Silurien-Dévonien dans le but de définir les « Plays » potentielles aux futures plans d’exploration. Au second volet, la mise au point d’une méthodologie rigoureuse, permettant l’étude minéralogique et l’évolution diagénétique des faciès, sous différents aspect ; la quantification de la porosité, la définition des relations entre porosité et minéralogie. Ensuite caractériser les argiles radioactives du Llandoverien-Frasnien respectivement Silurien, Dévonien et minéraux associés (Lüning et al., 2004). Plus précisément les processus et mécanismes qui contrôlent les transformations des minéraux argileux (minéralogies et cristallochimies) en composante latérale mais aussi en fonction de la profondeur. Dans ce contexte, des missions de terrains seront entreprises dans les massifs du Fadnoun (Tassili Central), Oued Taïni, Oued Khabkhab ainsi que dans l’Oued Amassine (Tassili Occidental) qui nous permettront de décrire en surface les formations du Siluro-Dévonien (profondément étudiées par : Asses, A., 1987 - Massa, D., 1988 - Bekkouche, D., 1992 – IFP, Sonatrach, Beicip., 1999) qui renferment les argiles radioactives (‘hot’) shales et les niveaux réservoirs, situées à quelques centaines de kilomètres au Nord (Bassin de Berkine), sous 2500 à 3000 m de sédiments. Une première mission de terrain est déjà réalisée, ayant reçu un support financier de la R&D (Séjour de Recherche à l’étranger), ainsi que des facilitées administratives et logistiques respectivement du Ministère de la Culture et de l’office national du parc culturel du Tassili n’Ajjer (patrimoine mondial de l’UNESCO depuis 1982). D’autres missions ultérieures seront à organiser en fonction du planning du déroulement de la thèse. La première mission géologique de terrain a duré un mois sur le Plateau de Fadnoun (Tassili n’Ajjer central). Ceci dans différentes coupes géologique-type des affleurements du Silurien-Dévonien : l’Oued Imihrou, l’Oued Farzal, Gara Tihouririne (sur la route Illizi-Fort Tarat) et Isoutar (Djouder et al., 2014). Durant cette mission terrain nous avons pu assurer la concordance entre les thématiques et objectifs de départ et les réalisés sur terrain, entre autre : 1) la meilleure compréhension de la géométrie des corps sédimentaires, au sein du Plateau de Fadnoun et donc par extension dans le bassin ; 2) la description et l’analyse des faciès, grâce aux affleurements peu connus dans les oueds. Ils permettront une analyse, notamment en termes d’environnements sédimentaires, des formations du Silurien-Dévonien ; 3) application première dans son genre de la susceptibilité magnétique comme nouvel proxy, pour les corrélations lithostratigraphiques des unités du Silurien-Dévonien aux Tassilis. 4) réalisation d’un échantillonnage serré à différents niveaux pour couvrir tout l’intervalle de la dépression intra-Tassilienne et des Grès du Tassili Externe, et puis l’expédition du matériel, nécessaire aux analyses de laboratoires notamment à Liège, et collaborateurs. La confection de lames-minces (en cours) permettra l’étude de la minéralogie et de la pétrographie, et donc une meilleure compréhension des faciès et microfaciès, c’est à dire de leurs propriétés intrinsèques (systèmes hétérogènes et complexes). Les lames palynologiques permettront des datations précises de chaque niveau. Enfin, différentes analyses sur roche (minéraux argileux dans un Laboratoire partenaire de l’Université de Poitiers en France, susceptibilité magnétique, cathodoluminescence, analyses géochimiques des majeurs et des traces à l’ULg) permettront d’affiner les paramètres du paléoenvironnement (Da Silva et al., 2013). [less ▲]

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See detailEarly Prediction of Transient Voltage Sags caused by Rotor Swings
Weckesser, Tilman; Johannsson, Hjortur; Van Cutsem, Thierry ULg

in Proc. IEEE PES general meeting (2014, July)

The paper investigates various methods to predict voltage sags at load buses caused by large generator rotor swings and following a transient disturbance. Three different prediction methods are proposed ... [more ▼]

The paper investigates various methods to predict voltage sags at load buses caused by large generator rotor swings and following a transient disturbance. Three different prediction methods are proposed, which all use real-time measurements from PMUs. One of the methods uses a slightly extended version of the E-SIME method. The other two methods use measurements and process them by recursive least square estimation. It is shown that the prediction method employing E-SIME allows the earliest detection of a critical voltage sag with satisfactory accuracy. [less ▲]

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See detailOrder reduction in time integration caused by velocity projection
Arnold, Martin; Cardona, Alberto; Bruls, Olivier ULg

in Proceedings of the 3rd Joint International Conference on Multibody System Dynamics and the 7th Asian Conference on Multibody Dynamics (2014, July)

Holonomic constraints restrict the configuration of a multibody system to a subset of the configuration space. They imply so called hidden constraints at the level of velocity coordinates that may ... [more ▼]

Holonomic constraints restrict the configuration of a multibody system to a subset of the configuration space. They imply so called hidden constraints at the level of velocity coordinates that may formally be obtained from time derivatives of the original holonomic constraints. A numerical solution that satisfies hidden constraints as well as the original constraint equations may be obtained considering both types of constraints simultaneously in each time step (stabilized index-2 formulation) or using projection techniques. Both approaches are well established in the time integration of differential-algebraic equations. Recently, we have introduced a generalized- alpha Lie group time integration method for the stabilized index-2 formulation that achieves second order convergence for all solution components. In the present paper, we show that a separate velocity projection would be less favourable since it may result in an order reduction and in large transient errors after each projection step. This undesired numerical behaviour is analysed by a one-step error recursion that considers the coupled error propagation in differential and algebraic solution components. This one-step error recursion has been used before to prove second order convergence for the application of generalized-alpha methods to constrained systems. As a technical detail, we discuss the extension of these results from symmetric, positive definite mass matrices to the rank deficient case. [less ▲]

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See detailExcavation damaged zone modelling including hydraulic permeability evolution in unsaturated argilaceous rock
Pardoen, Benoît ULg; Levasseur, Séverine ULg; Collin, Frédéric ULg

in Khalili, Nasser; Russell, Adrian R.; Khoshghalb, Arman (Eds.) Unsaturated Soils: Research & Applications (2014, July)

The drilling of galleries induces damage propagation in the surrounding medium and creates the Excavation Damaged Zone (EDZ) in which the material properties are modified. The prediction of the fracture ... [more ▼]

The drilling of galleries induces damage propagation in the surrounding medium and creates the Excavation Damaged Zone (EDZ) in which the material properties are modified. The prediction of the fracture structure and flow properties evolution within this zone are major issues especially in the context of underground nuclear waste storage. Since experimental results indicate that shear strain localisation appears prior to fractures, we model the EDZ with strain localisation in shear band mode using the coupled local second gradient model. The evolution of the intrinsic hydraulic permeability inside the fractures is taken into consideration as well as the influence of gallery ventilation on the rock desaturation. The numerical results provide information about the damaged zone extension, structure and behaviour with good correspondence to in situ measurements and observations. [less ▲]

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See detailAt the Crossroads of Greek and Roman Medicine: the Contribution of Latin Papyri. I. Medical Texts
Marganne, Marie-Hélène ULg

in Maire, Brigitte (Ed.) 'Greek' and 'Roman' in Latin Medical Texts. Studies in Cultural Change and Exchange in Ancient Medicine (2014, July)

Far fewer Latin medical papyri, whether paraliterary, documentary or magical, have survived compared to Greek medical papyri, but they nonetheless provide interesting information about medical practices ... [more ▼]

Far fewer Latin medical papyri, whether paraliterary, documentary or magical, have survived compared to Greek medical papyri, but they nonetheless provide interesting information about medical practices in the Graeco-Roman world, the relationship between Greek and Latin medical languages, and the choices made to use one rather than the other, a subject that has never been exhaustively studied. As part of the update undertaken by CEDOPAL since 2008 of the Corpus Papyrorum Latinarum, published fifty years ago by the late Robert Cavenaile, we have inventoried Latin papyri containing medical references, classifying them by type or nature of content, provenance, form, layout and writing. We finally analyse their content and what it reveals about the reception of Greek medicine by Latin or Latin-speeking writers. [less ▲]

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See detailMovements of endemic and exotic fish in a large river ecosystem (Rhône, France)
Capra, Hervé; Pella, Hervé; Ovidio, Michaël ULg

in Proceedings of the 10th International Conference on Ecohydraulics (2014, July)

The aim of this study is to characterise the mobility templates of two patrimonial species of rheophilic cyprinids (Barbus barbus and Squalius cephalus) and of a species of exotic fish, the catfish ... [more ▼]

The aim of this study is to characterise the mobility templates of two patrimonial species of rheophilic cyprinids (Barbus barbus and Squalius cephalus) and of a species of exotic fish, the catfish (Silurus glanis), in an area of the upper Rhône River characterised by significant disruptions of flow and thermal regimes (caused by hydroelectric and nuclear power plants). Results reveal contrasted mobility patterns, habitat uses and home-range sizes between endemic and exogenous fish species, but with a high interindividual variability. [less ▲]

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See detailEnhancement of ray tracing method for radiative heat transfer with new isocell quasi-monte carlo technique and application to EUI space instrument
Jacques, Lionel ULg; Masset, Luc ULg; Kerschen, Gaëtan ULg

in Proceedings of the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, HEFAT2014 (2014, July)

Monte Carlo ray tracing method for thermal analysis. The rationale for this research is the speed-up of radiative heat transfer computation with the Finite Element Method, widely used in mechanical ... [more ▼]

Monte Carlo ray tracing method for thermal analysis. The rationale for this research is the speed-up of radiative heat transfer computation with the Finite Element Method, widely used in mechanical engineering especially for space structure design but not yet often for thermal analysis of these structures. Based on Nusselt’s analogy, the ray direction sampling is done by sampling the unit disc to derive the ray directions. Stratified sampling is applied to the unit disc that is divided into cells or strata into which random points are generated. The isocell method relies on cells that have the particularity of presenting almost the same area and shape. This enhances the uniformity of the generated quasi-random sequence of ray directions and leads to faster convergence. The isocell method is associated with different surface sampling to derive REFs. The method is benchmarked against ESARAD, the standard ray tracing engine of the thermal analysis software used in the European aerospace industry. Various geometries are used. In particular, one entrance baffle of the Extreme Ultraviolet Imager (EUI) instrument developed at the Centre Spatial de Liège in Belgium is presented. The EUI instrument of the Solar Orbiter European Space Agency mission and will be launched in a 0.28 perihelion orbit around the Sun in 2018. [less ▲]

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See detailOn the convergence of relaxation schemes to couple phasor-mode and electromagnetic transients simulations
Plumier, Frédéric ULg; Geuzaine, Christophe ULg; Van Cutsem, Thierry ULg

in Proceedings of the IEEE PES General Meeting (2014, July)

Hybrid simulations combining phasor-mode and electromagnetic transients models aim at taking advantage of computational speed of the former and accuracy of the latter. For simulation accuracy, a ... [more ▼]

Hybrid simulations combining phasor-mode and electromagnetic transients models aim at taking advantage of computational speed of the former and accuracy of the latter. For simulation accuracy, a relaxation process is used, which consists of iterating between both models. The convergence properties of this relaxation process are investigated. The speed of convergence is assessed when the variables exchanged at the interface between both models are respectively pure voltage/current sources, Norton/Thévenin equivalents, or a combination of them. Iteratively updated Norton/Thévenin equivalents are shown to drastically reduce the number of relaxation iterations. [less ▲]

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See detailComputation of damped nonlinear normal modes with internal resonances: a boundary value approach
Renson, Ludovic ULg; Touzé, Cyril; Kerschen, Gaëtan ULg

in Proceedings of the 8th European Nonlinear Dynamics Conference (ENOC 2014) (2014, July)

This paper considers the computation of nonlinear normal modes (NNMs) defined as two-dimensional manifolds in phase space. Because existing methods use explicit manifold parameterization, NNM computation ... [more ▼]

This paper considers the computation of nonlinear normal modes (NNMs) defined as two-dimensional manifolds in phase space. Because existing methods use explicit manifold parameterization, NNM computation in the presence of internal resonances requires multiple pairs of constraint coordinates. This paper investigates an alternative method for which the manifold is computed using successive boundary value problems. [less ▲]

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See detail3D analysis and determination of stride parameters for different type of foot strike in running
Bury, Thierry ULg

in Abstract book of the 19th Annual Congress of the ECSS Amsterdam (2014, July)

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See detailSoil compaction resulting from different soil tillage systems
Destain, Marie-France ULg; Roisin, Christian; Mercatoris, Benoît ULg

in ASABE - CSBE/ASABE Joint Meeting Presentation (2014, July)

The effects of long-term use (8 years) of two different tillage systems were assessed on a Luvisol, under temperate climate (Belgium). The tillage treatments were (i) conventional tillage (CT) with ... [more ▼]

The effects of long-term use (8 years) of two different tillage systems were assessed on a Luvisol, under temperate climate (Belgium). The tillage treatments were (i) conventional tillage (CT) with moldboard ploughing to 27 cm depth and (ii) reduced tillage (RT) with a spring tine cultivator to 10 cm depth. The measurements included bulk density (BD) and precompression stress (Pc) chosen as indicators of mechanical strength, and the pore size distribution (PSD) measured by mercury intrusion porosimetry (MIP). The tillage systems, the depth and their interaction had a significant effect on BD, Pc and PSD. In CT, in the topsoil, the soil strength was low and the total porosity n was about 50 %. In the subsoil, n decreased to 43 %. The PSD of CT was uni-modal in topsoil and subsoil in the MIP measurement range. The mean value of the mode rmax diminished from the topsoil toward the subsoil (from 2.5 microns to 1.9 microns). In RT, in the topsoil, the soil strength was higher than CT. BD did not vary much according to the depth. The total porosity n of RT was comprised between 40-45 % in the soil profile. The PSD was uni-modal and rmax increased from topsoil (around 2 microns) to subsoil (> 3 microns). This suggested the agglomeration of fine particles under the long-term action of mechanical loads, climatic agents, biological organisms or clay minerals acting as cementing agents. These phenomena could be at the origin of the increase of Pc with the depth without significant modification of BD. Such high values of Pc could be responsible of negative effects on root-growth leading to a more superficial root lateral development. [less ▲]

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See detailRisk assessment of soil compaction in Walloon Region
D'Or, Dimitri; Destain, Marie-France ULg

in Proceedings of geoENV2014 (2014, July)

It is well established that soil compaction affects the growth and functioning of roots and disrupts the activity of microfauna and soil microorganisms, resulting in a loss of yields. Agriculture and ... [more ▼]

It is well established that soil compaction affects the growth and functioning of roots and disrupts the activity of microfauna and soil microorganisms, resulting in a loss of yields. Agriculture and forestry using increasingly heavy machines, the risk of soil compaction is increasing accordingly. Chosen as indicator of the susceptibility of soils to compaction, the precompression stress (Pc) is calculated using the pedotransfer functions (PTFs) proposed by Horn and Fleige (2003). These PTFs involve eight parameters linked to the hydraulic and mechanical behaviour of soils: organic matter content, bulk density, air capacity, available and non-plant available water capacity, saturated hydraulic conductivity, cohesion and angle of internal friction. The challenge consists in producing Pc maps at the regional scale for Wallonia. Those maps should also be accompanied by estimation uncertainty map. Finally, the results should be exploited to produce compaction risk maps according to various frequent scenarios. In this paper, a methodology is proposed, combining geostatistics and Monte Carlo simulations, to achieve these goals. [less ▲]

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See detailExperimental analysis of 2:1 modal interactions with noncommensurate linear frequencies in an aerospace structure
Noël, Jean-Philippe ULg; Renson, Ludovic ULg; Kerschen, Gaëtan ULg

in Proceedings of the 8th European Nonlinear Dynamics Conference (ENOC) (2014, July)

Nonlinear interactions between modes with noncommensurate linear frequencies are studied. It is experimentally evidenced that a strongly nonlinear, full-scale aerospace structure may exhibit such 2:1 ... [more ▼]

Nonlinear interactions between modes with noncommensurate linear frequencies are studied. It is experimentally evidenced that a strongly nonlinear, full-scale aerospace structure may exhibit such 2:1 interactions in typical testing conditions. The experimental observations are compared with numerical predictions. [less ▲]

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See detailModeling the hygrothermal response of a prefabricated straw bale panel and assessing its impact on indoor climate
Dubois, Samuel ULg; Evrard, Arnaud; Lebeau, Frédéric ULg

in 2014 ASABE and CSBE/SCGAB Annual International Meeting (2014, July)

Crop-based materials show many qualities in the quest for construction products with low environmental impact in the construction sector. Their ability to exchange moisture with indoor air offers new ... [more ▼]

Crop-based materials show many qualities in the quest for construction products with low environmental impact in the construction sector. Their ability to exchange moisture with indoor air offers new opportunities for improving interior user comfort and eventually buildings energy performance. Modeling their hygrothermal behavior has thus focused much attention, one of the main objectives being to assess more objectively the resulting performance at building scale. The first natural step in this modeling process is to understand the specific dynamics of heat and mass transfer within such materials. The Building Element Heat Air and Moisture (BEHAM) numerical models were designed to accurately predict internal conditions encountered in materials with partial balance equations. This envelope-based approach, however, requires the knowing of the interior and exterior climate conditions prior to the study. Therefore, it forbids any assessment of mutual exchange between the envelope to the indoor air and prevents any serious validation of the overall performance of materials. In response to this problem, the importance of developing whole building hygrothermal model has recently been raised. General scientific computational tools like MATLAB seem particularly adapted to perform this scaling-up, given their high flexibility and tools integration potentialities. In this communication we study a prefabricated straw bale panel subjected to two distinct and simple solicitations in a climatic chamber. A whole building hygrothermal model developed in MATLAB is then validated with the experimental datasets. The evolution of indoor conditions under the different tests is analyzed in details with an assessment of straw bales performance. [less ▲]

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See detailVibration analysis by speckle interferometry with CO2 lasers and microbolometers arrays
Vandenrijt, Jean-François ULg; Thizy, Cédric ULg; Georges, Marc ULg

in Imaging and Applied Optics 2014, OSA Technical Digest (online) (2014, July)

Speckle interferometry in the time-average mode in long wave infrared is shown for observing the mode shapes of vibrating objects. The long wavelength allows observing larger vibration displacements than ... [more ▼]

Speckle interferometry in the time-average mode in long wave infrared is shown for observing the mode shapes of vibrating objects. The long wavelength allows observing larger vibration displacements than what is achieved with visible wavelengths. [less ▲]

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See detailOptimization Of A Heat Pump For Satellite Cooling
Bell, Ian ULg; Lemort, Vincent

in 15 th International Refrigeration and Air Conditioning Conference at Purdue (2014, July)

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See detailAuf dem Weg zu einer neuen institutionellen Technologiefolgenabschätzung. TA in der Wallonie
Delvenne, Pierre ULg; Rosskamp, Benedikt ULg

in Decker, Michael; Bellucci, Sergio; Bröchler, Stephan (Eds.) et al Technilfolgenabschätzung im politischen System (2014, July)

Seit den offensiven Flämischen Technologie-Förderprogrammen in den achtziger Jahren, hat sich der technologische Graben zwischen dem Norden Belgiens und der von Deindustrialisierung stark betroffenen ... [more ▼]

Seit den offensiven Flämischen Technologie-Förderprogrammen in den achtziger Jahren, hat sich der technologische Graben zwischen dem Norden Belgiens und der von Deindustrialisierung stark betroffenen Wallonie weiter entwickelt. Hinzu kommt, dass Flandern im Jahre 2000 eine para-parlamentarische TA Institution eingeführt hat. Ein solches Unterfangen befand sich bis vor kurzem nicht auf der politischen Agenda der Wallonischen Entscheidungsträger. Zwischen 1994 und 2002 missglückte ein erstes TA Experiment, das sich sehr stark an das Baden-Württembergische Regional-TA Modell anlehnte. Zu diesem Zeitpunkt waren die Wallonischen Institutionen noch sehr jung und vor allem mit der Staatsreform befasst. Außerdem war das Interesse der traditionellen Sozialpartner (sprich Arbeitgeber- und Arbeitnehmerverbände) für TA nur bedingt vorhanden und der Bezug zur parlamentarischen Arbeit sehr begrenzt. Wir werden historisch nachverfolgen, wie es zu einer gemeinsamen Regierungserklärung des sozialistischen Ministers für Wirtschaft, Kleinunternehmen, Außenhandel und Neue Technologien sowie Hochschulwesen Jean-Claude Marcourt und des Grünen-Ministers für nachhaltige Entwicklung, öffentliche Ämter, Energie, Wohnungswesen und Forschung Jean-Marc Nollet kam, welche die Gründung eines Instituts für TA vorsieht. Diese ist teilweise zurückzuführen auf eine prospektive Aktionsforschung an der Universität Lüttich aus dem Jahr 2008 die ein weites Spektrum von Innovationsakteuren zu ihrer Haltung gegenüber institutionalisierter TA in der Wallonie befragt hat. Bei der Vorstellung dieser Studie, haben sich eine Reihe von Regionalabgeordneten für die Schaffung eines Instituts für TA ausgesprochen und wenig später eine parlamentarische Resolution verabschiedet. Wir werden auf die organisatorischen und programmatischen Aspekte, wie sie in den Regierungsplänen vorgesehen sind, eingehen. Die Originalität des Wallonischen Projekts ist u.a. der besondere Fokus auf wirtschaftliche Missionen. Mit dem ökonomischen Sektor als Adressaten soll u.a. die Wallonische Wirtschaft in strategischen Technologiebereichen unterstützt werden. Dabei wird viel Hoffnung in das Management von sozial-technologischen Kontroversen und in Wissenschaftskommunikation gesteckt. Neu ist auch der Ansatz, die Tradition der belgischen Sozialkonsultation auf gewisse Stakeholder-Gruppen auszuweiten und die Ambition partizipatorische Methoden zu nutzen, die im Wallonischen Kontext noch wenig verbreitet sind. Das aktuelle Projekt ist jedoch nicht frei von gegenwärtigen politischen Spannungen. Diese hängen sehr stark von parteipolitischen Ansichten sowie unterschiedlichen Positionen der zuständigen Ministerkabinette zur Staatsreform ab. Ferner gilt es auf die Eigenheiten eines solchen Instituts einzugehen und dessen formelle und informelle Adressaten sowie die Verbindung zu weiteren wissenschaftlichen, politischen und administrativen sowie zivilgesellschaftlichen Akteuren zu erläutern. Zuletzt werden wir auf die Besonderheiten der belgischen politischen Institutionen eingehen um besondere Risiken und Herausforderungen einer jungen TA Institution zu skizzieren. [less ▲]

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See detailOrthanc - Logiciel libre pour l'imagerie médicale en milieu hospitalier
JODOGNE, Sébastien ULg; LENAERTS, Eric ULg; COUCKE, Philippe ULg et al

in Communications de la Conférence Francophone en Gestion et Ingénierie des Systèmes Hospitaliers (GISEH 2014) (2014, July)

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See detailFatigue index reproducibility in isokinetic testing
Paulus, Julien ULg; Croisier, Jean-Louis ULg; Bosquet, Laurent et al

in De Haan, Arnold; De Ruiter, Jo; Tsolakidis, Elias (Eds.) Book of abstracts (2014, July)

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See detailA wavelet leaders-based climate classification of European surface air temperature signals
Deliège, Adrien ULg; Nicolay, Samuel ULg

in Ruiz Garcia, Gonzalo; Rojas Ruiz, Ignacio (Eds.) Proceedings of the International work-conference on Time Series: Volume 1, Granada 25-27 June 2014 (2014, June 25)

We explain the wavelet leaders method, a tool to study the pointwise regularity of signals, which is closely related to some functional spaces. We use the associated multifractal formalism to show that ... [more ▼]

We explain the wavelet leaders method, a tool to study the pointwise regularity of signals, which is closely related to some functional spaces. We use the associated multifractal formalism to show that surface air temperature signals are monofractal, i.e. these climate time series are regularly irregular. Then we use this result to establish a climate classification of weather stations in Europe which matches the Köppen-Geiger climate classification. This result could give rise to new criteria to determine the efficiency of current climatic models. [less ▲]

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See detailAntioxidant capacity and phenolic composition of red wines from various grape varieties : specificity of pinot noir.
degives, Julien; Kevers, Claire ULg; DEFRAIGNE, Jean ULg et al

in Giuseppe Viali (Ed.) 3rd international conference on cellular environmental stressors in biology and medicine : focus on redox reactions (2014, June 25)

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See detailCalculation of third order joint acceptance function for line-like structures
Blaise, Nicolas ULg; Canor, Thomas ULg; Denoël, Vincent ULg

in Proceedings of the XIII Conference of the Italian Association for Wind Engineering (2014, June 24)

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See detailSPATIODATA, un modèle de bâtiment non-constructif, collaboratif et multi-usage
Delfosse, Vincent ULg; Boulanger, Christelle ULg; Jeunejean, Aurélie ULg et al

in Actes du 6ème Séminaire de Conception Architecturale Numérique (2014, June 19)

There is an increasing number of mobile applications supporting specific activities related to the indoor building environment. SpatioData is a research project aiming at the development of a ... [more ▼]

There is an increasing number of mobile applications supporting specific activities related to the indoor building environment. SpatioData is a research project aiming at the development of a collaborative platform for the effective sharing of building-related data and supporting a wide range of different activities. This paper discusses the specific data model at the heart of the project. A comparison with the traditional BIM models is given in order to motivate the choices made in this project. [less ▲]

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See detailExperimental tests and numerical modelling on eight slender steel columns under increasing temperatures
Franssen, Jean-Marc ULg; Zhao, Bin; Gernay, Thomas ULg

in Li, G.Q.; Jiang, S.C.; Chen, Suwen (Eds.) et al Progress on Safety of Structures in Fire (2014, June 11)

In order to fill the lack of knowledge about slender elements behavior at elevated temperatures,, a European research project called FIDESC4 has been funded by the RFCS. This project involves experimental ... [more ▼]

In order to fill the lack of knowledge about slender elements behavior at elevated temperatures,, a European research project called FIDESC4 has been funded by the RFCS. This project involves experimental testing, parametric numerical analyses and development of simple design rules. The present paper reports the characteristics and the results of the FIDESC4 experimental test campaign performed at the University of Liege on slender steel columns at elevated temperatures. A total of eight columns have been tested, all of them with I shape section. Six columns were made of welded sections (some prismatic and some tapered members) and two columns were with hot rolled sections. The nominal length of the columns was 3 meters with the whole length being heated. The strength of the material (webs and flanges) was measured on sample before the tests. The order of magnitude of the initial geometrical imperfections was recorded. The columns were not restrained against longitudinal thermal elongation. The supports at the ends were cylindrical thus inducing a restrain against rotation in one plane while allowing rotation in the other plane. The allowed direction of rotation was chosen in each test to induce buckling around the strong or the weak axis. The load was applied at ambient temperature and maintained for a period of 15 minutes after which the temperature was increased under constant load. The load was applied concentrically on some tests and with an eccentricity in other tests. The load eccentricity was either applied at both ends, leading to constant bending moment distribution along the length, or at one end only, leading to a triangular bending moment distribution. Heating was applied by electrical resistances enclosed in ceramic pads. The columns and the ceramic pads were wrapped in ceramic wool insulating material. This technique was preferred to gas heating in a standard test furnace because it allows applying a slower and better controlled heating rate and thus obtaining a more uniform temperature distribution in the member. It is also easier to measured lateral displacements of the column. Preliminary blank tests were performed on unloaded specimen in order to determine the heating range to be used later on the loaded columns. The paper will also report on a modification of the heating technique that was applied and improved significantly the uniformity in the temperature distribution. Numerical simulations were performed before the tests using shell elements of the software SAFIR and assumed values of the material properties in order to predict the failure modes. It was essentially crucial to determine whether lateral supports at intermediate levels should be provided in order to ensure failure in the desired direction. Experience showed that the failure modes developed as predicted by the numerical simulations. Besides a thorough description of the experiments, the paper will also present the obtained results in terms of failure mode, ultimate temperature and evolution of longitudinal and transverse displacement. Some information will also be given about the level of detail that has to be used in the numerical model in order to get accurate results at a reasonable price. [less ▲]

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See detailLe sort des travailleurs d’une entreprise en réorganisation judiciaire
Kéfer, Fabienne ULg; Gailliet, Guillaume ULg

in Clesse, Jacques (Ed.) Questions choisies de droit social. Hommage à Michel Dumont (2014, June 06)

Le droit de l’entreprise en difficulté entretient avec le droit du travail des liens tendus. La préservation du potentiel économique de l’entreprise s’affronte aux dispositions visant à éviter la ... [more ▼]

Le droit de l’entreprise en difficulté entretient avec le droit du travail des liens tendus. La préservation du potentiel économique de l’entreprise s’affronte aux dispositions visant à éviter la dégradation de la situation des travailleurs. Le complexe normatif étudié reflète le point actuel du rapport de force entre le monde économique et les syndicats. Les salariés sont, en définitive, amenés à faire une grande partie du sacrifice nécessaire pour atteindre l’objectif économique recherché. Ce constat est perceptible dans l’hypothèse d’une réorganisation par accord collectif et dans celle du transfert sous autorité de justice, qui témoignent des rapports complexes entre les intérêts économiques et sociaux. La conciliation de ces intérêts divergents s’effectue sous la surveillance du juge. [less ▲]

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See detailOn-the-fly domain adaptation of binary classifiers
Pierard, Sébastien ULg; Marcos Alvarez, Alejandro ULg; Lejeune, Antoine ULg et al

in 23rd Belgian-Dutch Conference on Machine Learning (BENELEARN) (2014, June 06)

This work considers the on-the-fly domain adaptation of supervised binary classifiers, learned off-line, in order to adapt them to a target context. The probability density functions associated to ... [more ▼]

This work considers the on-the-fly domain adaptation of supervised binary classifiers, learned off-line, in order to adapt them to a target context. The probability density functions associated to negative and positive classes are supposed to be mixtures of the source distributions. Moreover, the mixture weights and the priors are only available at runtime. We present a theoretical solution to this problem, and demonstrate the effectiveness of the proposed approach on a real computer vision application. Our theoretical solution is applicable to any classifier approximating Bayes' classifier. [less ▲]

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See detailExploration du récit de vie d’adolescents
Poudat, Céline; Boulard, Aurore ULg

in Née, Emilie; Daube, Jean-Michel; Valette, Mathieu (Eds.) et al Proceedings-actes des 12èmes journées d'analyse statistique de données textuelles (2014, June 05)

The present paper follows on from the research we presented in previous JADT (Boulard, Poudat, Gauthier 2012). We still focus on the development of narrative competence (Habermas et Bluck 2000) in ... [more ▼]

The present paper follows on from the research we presented in previous JADT (Boulard, Poudat, Gauthier 2012). We still focus on the development of narrative competence (Habermas et Bluck 2000) in children and adolescents. Although children develop narrative skills, life narratives only emerge in adolescence. On the basis of a corpus made of spontaneous oral speech, we had empirically demonstrated that pre-adolescents aged of 12 had developed stabilized narrative skills enabling them to produce life narratives. Here, we propose a first exploration of the overall structure of adolescent life stories, thanks to a corpus of 268 oral self narratives completed with a questionnaire. [less ▲]

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See detailLa psychopathologie à la lumière des histoires de vie : Etude de la fonction narrative d’adolescents obèses et dépressifs.
Jadin, Aurore ULg; Gauthier, Jean-Marie ULg; Boulard, Aurore ULg

in Née, Emilie; Daube, Jean-Michel; Valette, Mathieu (Eds.) et al Proceedings-Actes des 12èmes journées internationales d'analyse statistique de données textuelles (2014, June 05)

Obesity in adolescence is a complex chronic illness with havy consequences in short, medium and long terms, both in terms of physical health and mental health, disturbing the body and identity of these ... [more ▼]

Obesity in adolescence is a complex chronic illness with havy consequences in short, medium and long terms, both in terms of physical health and mental health, disturbing the body and identity of these youngs (High Authority of Health, 2011; Nietsen and Bruwier, 2007). The literature mentions depression as a pathology associated with obesity. Some researchers consider obesity as a cause of depressive symptoms while others researchers see depression like a risk factor for excessive weight gain (Blaine, 2008). Depression in adolescence has been the subject of epidemiological studies for some years. In adolescents, the prevalence rates vary from 5 to 7 % for major depressive episode (MDE) with a prevalence of 2 girls for one boy (Alvin and Marcelli, 2005). The specific symptoms of depressed mood are present in 30-40 % of schooled adolescents (Boulard et al., 2012). During adolescence, the individual acquires the ability to link the various elements of one’s life and build a coherent life story. The adolescent will write one’s story in a personal context. According to Habermas et al. (2008), both the form and the content of life stories show how the individual integrates the lived experiences in a coherent whole. Based on the statistical analysis of textual data, we compared the life stories of 28 obese adolescents, depressed schooled adolescents, depressed hospitalized adolescents and control ones. The first results show specific structures and particular contents depending on these groups. The use of pronouns, temporal markers and the reported events differ by groups. Beyond clinical results, this research also highlights the interest of statistical analysis of textual data (ADT) to improve the understanding of adolescent’s psychopathology. [less ▲]

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See detailSIMPLIFIED SEISMIC ANALYSIS OF LOCK GATES
Buldgen, Loïc ULg; Degée, Hervé ULg; Lesourne, Hervé et al

in PIANC 2014 Conference (2014, June 02)

The paper deals with the seismic design of lock gates. When such structures are submitted to an earthquake, the water contained in the chamber is responsible for an additional hydrodynamic pressure acting ... [more ▼]

The paper deals with the seismic design of lock gates. When such structures are submitted to an earthquake, the water contained in the chamber is responsible for an additional hydrodynamic pressure acting on the gate. This one is the sum of three different parts, respectively called the convective, rigid and flexible contributions. The two first ones have already been extensively studied in the literature, but the flexible part is more difficult to assess as it is largely influenced by the coupling occurring between the fluid and the gate. To overcome this difficulty, it is of course possible to use finite elements software, but doing so is not always convenient. This is why some research have been undertaken to provide a rapid way for approximating the flexible pressure on lock gates. This is achieved by applying the analytical approach that is shortly presented in this paper. As a matter of validation, the results obtained through this simplified procedure are compared to numerical solutions. The agreement between both of them is found to be satisfactory. [less ▲]

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See detailRay tracing enhancement for space thermal analysis: isocell method
Jacques, Lionel ULg; Masset, Luc ULg; Kerschen, Gaëtan ULg

in Sarler, Bozidar; Massaroti, Nicola; Nithiarasu, Perumal (Eds.) Third International Conference on Computational Methods for Thermal Problems (2014, June 02)

The finite element method (FEM) is widely used in mechanical engineering, especially for space structure design. However, FEM is not yet often used for thermal engineering of space structures where the ... [more ▼]

The finite element method (FEM) is widely used in mechanical engineering, especially for space structure design. However, FEM is not yet often used for thermal engineering of space structures where the lumped parameter method is still dominant. Radiative exchange factors (REFs) are usually computed through Monte Carlo ray-tracing. Due to the large number of elements composing a FE model, the computation of the REFs is prohibitively expensive. The developments of the new Isocell quasi-Monte Carlo ray tracing method are presented. The Isocell method enhances the uniformity of the generated quasi-random sequence of ray directions and leads to faster convergence. It is associated with different surface sampling to derive the REFs. The method is benchmarked against ESARAD, the standard ray-tracing engine for thermal analysis used in the European aerospace industry. Various geometries are used. In particular, one entrance baffle of the Extreme Ultraviolet Imager (EUI) instrument developed at the Centre Spatial de Liège in Belgium is used. The EUI instrument of the Solar Orbiter European Space Agency mission and will be launched in a Sun-centered 0.28 perihelion orbit in 2018. [less ▲]

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See detailDe la matière à l'espace: une voie d'intégration numérique et matérielle
Delvaux, Frederic ULg; Bianchi, Romuald ULg; Jancart, Sylvie ULg

in Kubicki, Sylvain; Halin, Gilles; Bignon, Jean-CLaude (Eds.) Scan 14 séminaire de conception architecturale numérique : Interaction(s) des maquettes numériques (2014, June 01)

From a collaboration of formal and architectural research between architect and artist, we present the summary of an experimental approach that illustrates the creation and construction of a functional ... [more ▼]

From a collaboration of formal and architectural research between architect and artist, we present the summary of an experimental approach that illustrates the creation and construction of a functional space, located at the borders of the sculpture and the architecture. We present a look at the method, according to a revised approach to digital modeling / re-design. This has been an exploratory approach through the study of three generic models of the form. We present the experimental method, the selection of relevant parameters in form finding coupled with the integration of material and physical data specific to the object. We also expose the benefits of this approach, its limitations and the possibilities it offers as a generic point of view. [less ▲]

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See detailAn Investigation into the Influence of External Walls Reflectivity on the Indoor Daylight Availability in Desert Climates
Hegazy, Mohamed Amer; Attia, Shady ULg

in Conference Proceedings: Building Simulation and Optimization 2014 (2014, June)

Hot arid climates are characterized by clear sunny sky most of the year time. Such climates affects the urban morphology, which requires sometimes dense urban fabric. Narrow streets have significant ... [more ▼]

Hot arid climates are characterized by clear sunny sky most of the year time. Such climates affects the urban morphology, which requires sometimes dense urban fabric. Narrow streets have significant effect on the amount of daylight permeating indoor residential zones, which may have a negative or positive effect on the overall visual performance. This paper studies the quantitative effect of using different Façade reflectivity ratios, under different street widths, on the indoor daylight autonomy. The researcher performed a parametric analysis using DIVA for Rhino simulation tool on a hypothetical residential building unit with various window ratios facing neighbouring buildings. Four main orientations were examined under different urban contexts and wall reflectivity. This paper aims to measure daylight autonomy and address possible strategies and solutions to achieve better daylighting that can be used by architects at early design stages of housing developments in the desert climates. [less ▲]

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See detailArrival of european eel in Belgian Part of the Meuse: who and how are they?
Nzau Matondo, Billy ULg; Benitez, Jean-Philippe ULg; Dierckx, Arnaud ULg et al

in Proceedings of the 10th International Conference on Ecohydraulics (2014, June)

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See detailUsing intensive multiyear fish-pass monitoring to analyse seasonal upstream movement patterns of patrimonial holobiotic potomadromous fish species in a medium size river
Benitez, Jean-Philippe ULg; Nzau Matondo, Billy ULg; Dierckx, Arnaud ULg et al

in Proceedings of the 10th International Conference on Ecohydraulics (2014, June)

Belgian rivers are fragmented by numerous obstacles which considerably limit the free access of fish to functional habitats. Fish-passes are major tools used to increase stream continuity and improve ... [more ▼]

Belgian rivers are fragmented by numerous obstacles which considerably limit the free access of fish to functional habitats. Fish-passes are major tools used to increase stream continuity and improve connectivity in the upstream direction. Using two modern multispecies fish-passes, this study aims to investigate multiyear abundance of holobiotic potamodromous fish and their seasonal movement patterns in relation with environmental factors. The fish passes were monitored continuously during 5 and 7 years and are located in two Belgian streams: the (19.3m³.s-1) and the Berwinne (1.9m³.s-1). Results revealed the presence of 20 different fish species, 14 species in the Berwinne and 19 species in the occurrence, salmonids and cyprinids species were predominant. A great interspecific and intraspecific variability in capture periodicity and in terms of stimulation by combination of factor environmental was observed. This study highlights the complexity and the omnipresence of holobiotic potamodromous fish movements at different life stages, in medium size river and brings new information on fish passes efficiency and use by these poorly known species. [less ▲]

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See detailLe B.I.M et la maquette virtuelle comme moyen pédagogique permettant le rapprochement entre les cours d'informatique et l'enseignement du projet d'architecture
Boutemadja, Abdelkader ULg; Driesmans, Carine ULg; Jancart, Sylvie ULg

in Kubicki, Sylvain; Halin, Gilles; Bignon, Jean-Claude (Eds.) Scan 14 sémainaire de conception architecturale numérique : Interaction(s) des maquettes numériques (2014, June)

In the context of this paper, we pose the question of the conditions of possible link between computer courses and design projet. The integration of schools of architecture at universities is an ... [more ▼]

In the context of this paper, we pose the question of the conditions of possible link between computer courses and design projet. The integration of schools of architecture at universities is an opportunity to focus in the experiments made in this direction and to propose to implement the terms of this rapprochement. For us, it is important that this approach lies in the Bachelor years in a common core for all students. [less ▲]

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See detailDistributed Model-free Control of Photovoltaic Units for Mitigating Overvoltages in Low-Voltage Networks
Aristidou, Petros ULg; Olivier, Frédéric ULg; Hervas, Maria Emilia et al

in Proc. of CIRED 2014 workshop (2014, June)

In this paper, a distributed model-free control scheme to mitigate overvoltage problems caused by high photovoltaic generation in low-voltage feeders is proposed. The distributed controllers are ... [more ▼]

In this paper, a distributed model-free control scheme to mitigate overvoltage problems caused by high photovoltaic generation in low-voltage feeders is proposed. The distributed controllers are implemented on the photovoltaic inverters and modulate the active and reactive power injected into the network. In particular, they direct photovoltaic units first to consume reactive power and, if necessary, curtail active power generation to reduce high voltages in the feeder. [less ▲]

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See detailCHARACTERIZATION OF PROTEINURIA IN DOGUE DE BORDEAUX DOGS USING ELECTROPHORESIS AND URINARY BIOMARKERS
Lavoué, Rachel; Smets, P.; Trumel, Cathy et al

in Proceedings of the 2014 ACVIM Forum (2014, June)

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See detailGeometric parameters influence on Piano Key Weir hydraulic performances
Erpicum, Sébastien ULg; Archambeau, Pierre ULg; Pirotton, Michel ULg et al

in Chanson, Hubert; Toombes, Luke (Eds.) Hydraulic Structures and Society – Engineering Challenges (2014, June)

The Piano Key Weir is a recent evolution of the traditional labyrinth weir. Thanks to a reduced foot print, this nonlinear weir can be placed on the top of gravity dams. The Piano Key Weir geometry ... [more ▼]

The Piano Key Weir is a recent evolution of the traditional labyrinth weir. Thanks to a reduced foot print, this nonlinear weir can be placed on the top of gravity dams. The Piano Key Weir geometry involves a large number of geometric parameters. Several experimental studies have been carried out to investigate the main geometric parameters influencing the weir hydraulic efficiency and to define their optimal value. In this paper, the experimental data gathered at the University of Liege are re-examined to show how the weir height, the keys widths and the overhangs positions influence, for a given crest length magnification ratio, the weir discharge capacity. The theoretical rating curve of a standard linear weir is considered for comparison. The analysis highlights that the keys widths and overhangs lengths ratios influence significantly the Piano Key Weir efficiency, but less than the weir height. Considering the above mentioned results, a cost efficient design proposed in the literature is also proved to be close to the hydraulic optimum. [less ▲]

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See detailÉtude des changements de circulation au-dessus de l'océan Austral en été
Belleflamme, Alexandre ULg; Fettweis, Xavier ULg; Erpicum, Michel ULg

in Camberlin, Pierre; Richard, Yves (Eds.) Actes du XXVIIème colloque de l'Association de Climatologie - Climat : système & interactions (2014, June)

Over the five last decades, the reanalyses (ERA and NCEP/NCAR) show a strengthening of the pressure gradient between the southern hemisphere subtropical anticyclone belt and the southern circumpolar lows ... [more ▼]

Over the five last decades, the reanalyses (ERA and NCEP/NCAR) show a strengthening of the pressure gradient between the southern hemisphere subtropical anticyclone belt and the southern circumpolar lows during summer. With the help of an automatic circulation type classification, we show that the strengthening of the pressure gradient is generalised to all circulation types and, paradoxically, it does not cause circulation changes. It is probably implied by the strengthening of the temperature gradient between the tropics and the South Pole, without consequences on the general circulation. Our classification also allows a successful comparison between the two reanalyses in a region where the observation data are rare. [less ▲]

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See detailOn the Quality of BGP Route Collectors for iBGP Policy Inference
Cittadini, Luca; Vissicchio, Stefano; Donnet, Benoît ULg

in IFIP Networking (2014, June)

A significant portion of what is known about Internet routing stems out from public BGP datasets. For this reason, numerous research efforts were devoted to (i) assessing the (in)completeness of the ... [more ▼]

A significant portion of what is known about Internet routing stems out from public BGP datasets. For this reason, numerous research efforts were devoted to (i) assessing the (in)completeness of the datasets, (ii) identifying biases in the dataset, and (iii) augmenting data quality by optimally placing new collectors. However, those studies focused on techniques to extract information about the AS-level Internet topology. In this paper, we show that considering different metrics influences the conclusions about biases and collector placement. Namely, we compare AS-level topology discovery with \iac inference. We find that the same datasets exhibit significantly diverse biases for these two metrics. For example, the sensitivity to the number and position of collectors is noticeably different. Moreover, for both metrics, the marginal utility of adding a new collector is strongly localized with respect to the proximity of the collector. Our results suggest that the ``optimal'' position for new collectors can only be defined with respect to a specific metric, hence posing a fundamental trade-off for maximizing the utility of extensions to the BGP data collection infrastructure. [less ▲]

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See detailThe grassland model intercomparison of the MACSUR (Modelling European Agriculture with Climate Change for Food Security) European knowledge hub
Ma, Shaoxiu; Acutis, Marco; Barcza, Zoltan et al

in Proceedings of the 7th International Congress on Environmental Modelling and Software (iEMSs) June 15-19, 2014, San Diego, California, USA (2014, June)

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See detailMODEL PREDICTIVE CONTROL OF CONGESTION AND VOLTAGE PROBLEMS IN ACTIVE DISTRIBUTION NETWORKS
Soleimani Bidgoli, Hamid ULg; Glavic, Mevludin ULg; Van Cutsem, Thierry ULg

in Proc. of CIRED Workshop 2014 (2014, June)

This paper presents a centralized control scheme, inspired of Model Predictive Control (MPC), to manage thermal overloads and correct abnormal voltages in real-time. The control scheme is able to smoothly ... [more ▼]

This paper presents a centralized control scheme, inspired of Model Predictive Control (MPC), to manage thermal overloads and correct abnormal voltages in real-time. The control scheme is able to smoothly bring the system within the desired limits, taking into account its near-future evolution. The control method effectiveness is illustrated on a 20-kV, 32-bus network hosting four distributed generation units. [less ▲]

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See detailBayes Adaptive Reinforcement Learning versus Off-line Prior-based Policy Search: an Empirical Comparison
Castronovo, Michaël ULg; Ernst, Damien ULg; Fonteneau, Raphaël ULg

in Proceedings of the 23rd annual machine learning conference of Belgium and the Netherlands (BENELEARN 2014) (2014, June)

This paper addresses the problem of decision making in unknown finite Markov decision processes (MDPs). The uncertainty about the MDPs is modeled using a prior distribution over a set of candidate MDPs ... [more ▼]

This paper addresses the problem of decision making in unknown finite Markov decision processes (MDPs). The uncertainty about the MDPs is modeled using a prior distribution over a set of candidate MDPs. The performance criterion is the expected sum of discounted rewards collected over an infinite length trajectory. Time constraints are defined as follows: (i) an off-line phase with a given time budget can be used to exploit the prior distribution and (ii) at every time step of the on-line phase, decisions have to be computed within a given time budget. In this setting, we compare two decision-making strategies: OPPS, a recently proposed meta-learning scheme which mainly exploits the off-line phase to perform policy search and BAMCP, a state-of-the-art model-based Bayesian reinforcement learning algorithm, which mainly exploits the on-line time budget. We empirically compare these approaches in a real Bayesian setting by computing their performances over a large set of problems. To the best of our knowledge, it is the first time that this is done in the reinforcement learning literature. Several settings are considered by varying the prior distribution and the distribution from which test problems are drawn. The main finding of these experiments is that there may be a significant benefit of having an off-line prior-based optimization phase in the case of informative and accurate priors, especially when on-line time constraints are tight. [less ▲]

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See detailOn the Performance of the LISP Beta Network
Coras, Florin; Saucez, Damien; Iannone, Luigi et al

in IFIP Networking (2014, June)

The future Internet has been a hot topic during the past decade and many approaches towards this future Internet, ranging from incremental evolution to complete clean slate ones, have been proposed. One ... [more ▼]

The future Internet has been a hot topic during the past decade and many approaches towards this future Internet, ranging from incremental evolution to complete clean slate ones, have been proposed. One of the proposition, LISP, advocates for the separation of the identifier and the locator roles of IP addresses to reduce BGP churn and BGP table size. Up to now, however, most studies concerning LISP have been theoretical and, in fact, little is known about the actual LISP deployment performance. In this paper, we fill this gap through measurement campaigns carried out on the LISP Beta Network. More precisely, we evaluate the performance of the two key components of the infrastructure: the control plane (i.e., the mapping system) and the interworking mechanism (i.e., communication between LISP and non-LISP sites). Our measurements highlight that performance offered by the LISP interworking infrastructure is strongly dependent on BGP routing policies. If we exclude misconfigured nodes, the mapping system typically provides reliable performance and relatively low median mapping resolution delays. Although the bias is not very important, control plane performance favors USA sites as a result of its larger LISP user base but also because European infrastructure appears to be less reliable. [less ▲]

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See detailDouble Sweep Preconditioners for propagation problems solved by Optimized Schwarz Methods
Vion, Alexandre ULg; Geuzaine, Christophe ULg

in Proceedings of the 6th International Conference on Advanced COmputational Methods in ENgineering, ACOMEN 2014 (2014, June)

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See detailPrediction of macroscopic mechanical properties of a polycrystalline microbeam subjected to material uncertainties
Lucas, Vincent ULg; Wu, Ling ULg; Arnst, Maarten ULg et al

in Cunha, Álvaro; Caetano, Elsa; Ribeiro, Pedro (Eds.) et al Proceedings of the 9th International Conference on Structural Dynamics, EURODYN 2014 (2014, June)

The first resonance frequency is a key performance characteristic of MEMS vibrometers. In batch fabrication, this first resonance frequency can exhibit scatter owing to various sources of manufacturing ... [more ▼]

The first resonance frequency is a key performance characteristic of MEMS vibrometers. In batch fabrication, this first resonance frequency can exhibit scatter owing to various sources of manufacturing variability involved in the fabrication process. The aim of this work is to develop a stochastic multiscale model for predicting the first resonance frequency of MEMS microbeams constituted of polycrystals while accounting for the uncertainties in the microstructure due to the grain orientations. At the finest scale, we model the microstructure of polycrystaline materials using a random Voronoï tessellation, each grain being assigned a random orientation. Then, we apply a computational homogenization procedure on statistical volume elements to obtain a stochastic characterization of the elasticity tensor at the second scale of interest, the meso-scale. In the future, using a stochastic finite element method, we will propagate these meso-scale uncertainties to the first resonance frequency at the coarser scale. [less ▲]

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See detailDelivering Bad New in Service Encounters: a Customer Perspective
Delcourt, Cécile ULg; Gremler, Dwayne; van Riel, Allard et al

in SERVSIG (2014, June)

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See detailReceptor expression in craniopharyngiomas causing tumor growth in pregnancy: case report and review of the literature
VROONEN, Laurent ULg; TOME, Monica; THIRY, Albert ULg et al

in Abstract book : 57èmes Journées Internationales d'Endocrinologie Clinique - Henri-Pierre Klotz (2014, June)

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See detailThe Call for project proposals « Let’s live my village »: between free interpretations and compulsory readings regarding innovation and convivial village ambiance in Wallonia.
Schmitz, Serge ULg

in Les campagnes: espaces d'innovation dans un monde urbain (2014, June)

The paper scrutinizes 186 rural development projects selected on the short list of the first and second “Lets’ live my village!” calls. It examines trends concerning rural community life and the identity ... [more ▼]

The paper scrutinizes 186 rural development projects selected on the short list of the first and second “Lets’ live my village!” calls. It examines trends concerning rural community life and the identity of the leaders/brokers. It pays attention to the way that associations define rurality. Question 14 of the application form « Does your association act in rural areas? Explain” is the main source of information for content analysis and contingency tables [less ▲]

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See detailAnalysis versus synthesis for trending of gas-path measurement time series
Borguet, Sébastien ULg; Léonard, Olivier ULg; Dewallef, Pierre ULg

in Proceedings of ASME Turbo Expo 2014 (2014, June)

Gas-path measurements used to assess the health condition of an engine are corrupted by noise. Generally, a data cleaning step occurs before proceeding with fault detection and isolation. Classical linear ... [more ▼]

Gas-path measurements used to assess the health condition of an engine are corrupted by noise. Generally, a data cleaning step occurs before proceeding with fault detection and isolation. Classical linear filters such as the exponentially weighted moving average filter are traditionally used for noise removal. Unfortunately, these low-pass filters distort trend shifts indicative of faults, which increases the detection delay. The present paper investigates two new approaches to non-linear filtering of time series. On one hand, the synthesis approach reconstructs the signal as a combination of elementary signals chosen from a pre-defined library. On the other hand, the analysis approach imposes a constraint on the shape of the signal (e.g., piecewise constant). Both approaches incorporate prior information about the signal in a different way, but they lead to trend filters that are very capable at noise removal while preserving at the same time sharp edges in the signal. This is highlighted through the comparison with a classical linear filter on a batch of synthetic data representative of typical engine fault profiles. [less ▲]

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See detailSimple connectome inference from partial correlation statistics in calcium imaging
Sutera, Antonio ULg; Joly, Arnaud ULg; François-Lavet, Vincent ULg et al

in Proceedings of Connectomics 2014 (ECML 2014) (2014, June)

In this work, we propose a simple yet effective solution to the problem of connectome inference in calcium imaging data. The proposed algorithm consists of two steps. First, processing the raw signals to ... [more ▼]

In this work, we propose a simple yet effective solution to the problem of connectome inference in calcium imaging data. The proposed algorithm consists of two steps. First, processing the raw signals to detect neural peak activities. Second, inferring the degree of association between neurons from partial correlation statistics. This paper summarises the methodology that led us to win the Connectomics Challenge, proposes a simplified version of our method, and finally compares our results with respect to other inference methods. [less ▲]

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See detailWind Tunnel Testing of a VTOL MAV Propeller in Tilted Operating Mode
Theys, Bart; Dimitriadis, Grigorios ULg; Andrianne, Thomas ULg et al

in Proceedings of the 2014 International Conference on Unmanned Aircraft Systems (ICUAS 2014) (2014, May 30)

This paper presents experimental results of the full 3-axis force vector and 3-axis moment vector acting on a propeller, commonly used for a Vertical Take Off and Landing Micro Aerial Vehicle (VTOL MAV ... [more ▼]

This paper presents experimental results of the full 3-axis force vector and 3-axis moment vector acting on a propeller, commonly used for a Vertical Take Off and Landing Micro Aerial Vehicle (VTOL MAV). Measurements were carried out in a wind tunnel using a high resolution 6-axis force/moment sensor embedded in a customized test rig at several wind speeds, propeller rotational speeds and angles of the propeller shaft with respect to the air stream. Results show strong moments acting on the propeller in forward flight and unstable conditions in descending flight. Power calculations reveal a decrease in power consumption during slow forward flight and how motor efficiency can be maximized. [less ▲]

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See detailProgramme de revalidation multidisciplinaire post-cancer du sein : analyse des bénéfices éventuels sur la fonction physique et la qualité de vie
LECLERC, Anne-France ULg; FOIDART-DESSALLE, Marguerite ULg; COUCKE, Philippe ULg et al

in 29ème Congrès de la Sofmer et 19ème Congrès européen de Médecine Physique et de Réadaptation : Abstract book (2014, May 26)

Objective: To determine the potential benefits, both physically and psychologically, of a multidisciplinary rehabilitation program among women treated for breast cancer. Materials and Methods: Thirty ... [more ▼]

Objective: To determine the potential benefits, both physically and psychologically, of a multidisciplinary rehabilitation program among women treated for breast cancer. Materials and Methods: Thirty patients were recruited, sixteen in the control group and fourteen in the treated group. This group has benefited from a rehabilitation of three months including a supervised training and various psycho-educational sessions. The assessments, performed before and after the programme, included anthropometric and body composition measurements, a functional assessment and various questionnaires. Results: After three months, the health state (quality of life), emotional state, physical, cognitive and social functions and the symptoms of insomnia and anxiety significantly improve in the treated group. This observation also applies to the flexibility, maximal aerobic power / body weight, time to exhaustion during the physical effort test and walking distance in six minutes. In the control group, these improvements do not appear. Discussion: This preliminary study demonstrates the feasibility and benefits of a multidisciplinary approach in women after their treatments for breast cancer. [less ▲]

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See detailLe conseiller techno-pédagogique, amplificateur du développement professionnel des enseignants ?
Van de Poël, Jean-François ULg; Lecomte, Béatrice ULg; Schaffer, Patrick ULg et al

in Actes du 28ème Congrès de l'Association internationale de pédagogie universitaire (2014, May 20)

La communication présentera trois parcours d’enseignants différents accompagnés par l’IFRES dans la mise en oeuvre d’activités destinées à leurs étudiants de 1er BAC suite à une série de constats liés aux ... [more ▼]

La communication présentera trois parcours d’enseignants différents accompagnés par l’IFRES dans la mise en oeuvre d’activités destinées à leurs étudiants de 1er BAC suite à une série de constats liés aux difficultés rencontrées notamment en matière d’hétérogénéité du public et en matière de taux d’échec important constaté. Les parcours réflexifs et les activités mises en place qui en ont découlé seront analysés au regard des dimensions présentées dans le TPACK. Cette réflexion sera réalisée suite à une prise de données qualitatives auprès des trois enseignants concernés. « Enseigner est un processus complexe qui requiert de la part de l’enseignant des compétences multiples » (Koelher& Mishra, 2006, p.1017-1018, Eberly Center, 2012) et issues de plusieurs domaines (Glaser, 1984, Schulmann 1986, 1987, cités par Koelher& Mishra, 2006, p.61). Intégrer les technologies dans son enseignement complexifie encore plus la tâche pour l’enseignant. Afin de mieux représenter les relations qui existent entre les différents types de connaissances requises pour enseigner, Koelher& Mishra (2006, p. 62-67) ont développé le modèle TPACK (« Technological Pedagogical Content Knowledge ») sur la base du modèle du « Pedagogical Content Knowledge » de Schulman (1987, P. 8-10) auquel ils ont ajouté une dimension technologique qui interagit avec les composantes déjà présentes dans le modèle initial. Au confluent de l’enseignement et de la recherche, le conseiller techno-pédagogique est amené à accompagner les enseignants de son institution dans leurs « réflexions professionnelles » (Paquay, 1996, Perrenoud, 1998, Bass, 1999, Mc Kinney, 2004) ainsi que dans la mise en place d’activités d’enseignement dont la conception fait appel à un grand nombre de dimensions. Dans ce contexte d’accompagnement, le CTP représente donc une véritable interface entre l’enseignant et son questionnement et ce que la recherche en technologies éducatives et en pédagogie universitaire nous apprend. La communication s’interrogera donc également sur la contribution du conseiller technopédagogique (par ses attitudes, ses postures, etc.) à une accentuation, un renforcement de la dimension « recherche innovation » dans la professionnalisation des enseignants qu’il est amené à accompagner. [less ▲]

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See detailDévelopper la pratique réflexive chez des formateurs d’adultes travaillant en milieu associatif – Une analyse du dispositif SDR (Soutien au Développement de la Réflexivité)
Dewit, Olivier; Jérôme, Françoise ULg; Verpoorten, Dominique ULg

in Actes en ligne du 28ème Congrès de l’Association Internationale de Pédagogique Universitaire : "Pédagogie universitaire : entre recherche et enseignement" (2014, May 19)

Cet article présente un dispositif de soutien au développement de la réflexivité (SDR) mis en œuvre dans le cadre d'une formation pédagogique de formateurs d'adultes. Le dispositif SDR se compose de micro ... [more ▼]

Cet article présente un dispositif de soutien au développement de la réflexivité (SDR) mis en œuvre dans le cadre d'une formation pédagogique de formateurs d'adultes. Le dispositif SDR se compose de micro-activités soutenant, d’une part, une conceptualisation progressive de la notion même de réflexivité et, d'autre part, la prise de recul critique par rapport à des actions de terrain. Les données récoltées auprès de 10 participants indiquent que le dispositif est vecteur de progrès réflexif, sans que tous les participants atteignent pour autant le niveau de « praticien réflexif » (Donnay & Charlier, 2006) visé par la formation et opérationnalisé au travers de 5 indicateurs. Au-delà de ces résultats circonscrits, l’expérience contribue à étoffer la panoplie de techniques permettant de stimuler le retour sur soi, particulièrement dans des contextes de formation où un recours appuyé à l’écriture réflexive (telle que pratiquée dans un portfolio, un blog, un journal de bord) se révèlerait un exercice trop exigeant pour le public-cible ou trop chronophage par rapport à la durée ou la charge de travail liées à la formation. [less ▲]

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See detailMédecine & sport de haut niveau
Kaux, Jean-François ULg

in Sport et Médecine : droit au but (2014, May 15)

L’engouement pour les activités sportives demeure croissant auprès du grand public grâce à toute une série d’activités sportives novatrices (Zumba, Kaerobic, etc…) et de programmes de remise en forme ... [more ▼]

L’engouement pour les activités sportives demeure croissant auprès du grand public grâce à toute une série d’activités sportives novatrices (Zumba, Kaerobic, etc…) et de programmes de remise en forme (« Je cours pour ma forme », etc…), bénéfiques pour la santé. Cependant, les sportifs de haut niveau, professionnels ou non, valides ou handicapés, représentant l’excellence sportive, reconnus par le code et la charte du sport de haut niveau, ne représentent qu’une infime partie de la totalité des sportifs. Le sport de haut niveau repose sur des critères bien établis: la reconnaissance du caractère de haut niveau des disciplines sportives ; les compétitions de références (jeux olympiques, championnats d’Europe et du Monde…) ; la liste des sportifs de haut niveau ; les filières d’accès au sport de haut niveau. Les sportifs pratiquant au meilleur niveau bénéficient généralement de prédispositions physiques, adéquates au sport pratiqué. Cependant, sans entrainement spécifique (au sport pratiqué), ils ne pourraient pas atteindre ce niveau. Le médecin, travaillant dans l’ombre de ces sportifs, est là pour veiller sur leur santé, développer des stratégies de prévention lésionnelle et les soigner en cas de nécessité. Même s’il a la possibilité de superviser médicalement les compétitions sportives « en première loge », il est également souvent sous la pression arbitrale, des médias, des coaches, des présidents, des sportifs eux-mêmes… Au cours de sa carrière, le sportif risque de se blesser plus ou moins gravement, et se voit obligé de quitter la compétition pour laquelle il s’est préparé durant de nombreuses semaines voire des mois ou des années… Dans ce cas, il sera pris en charge par toute une équipe (kiné, chirurgien, préparateur physique, psychologue…) travaillant en synergie afin de le rétablir au plus vite et de retrouver son plus haut niveau. Avant le retour en compétition, une réathlétisation demeure indispensable. Celle-ci correspond à la reprise d’activité physique, comprenant : toute la phase de réadaptation à l’exercice la phase de transition entre les soins et la reprise de l’entraînement. Il s’agit d’un processus nécessaire à la prévention des blessures et à l’adaptation de l’organisme à un programme d’entraînement poussé. Cependant, il se peut que cette période de l’entraînement soit négligée en raison d’un manque de temps en vue d’un objectif trop proche, majorant le risque de récidive ou de nouvelle blessure. Le sportif de haut niveau se doit de garder une hygiène de vie parfaite, en ayant une alimentation équilibrée, et dénuée de toxique (alcool, drogue…) et en respectant des périodes de repos nécessaires entre les différentes phases d’activité physique. De plus, afin d’améliorer ses performances sportives, la préparation physique (endurance, résistance, force musculaire, souplesse…) et l’entrainement spécifique à chaque sport (technique, tactique, adresse et précision…) demeurent indispensables. Dès lors, la tentation de les améliorer artificiellement existe. En effet, le dopage consiste à absorber des substances ou à utiliser des actes médicaux afin d’augmenter artificiellement ses capacités physiques et/ou mentales. Or, l’utilisation de tout médicament devrait être limitée à des indications médicalement justifiées. Le code mondial anti-dopage est régit par l’Agence Mondiale Antidopage (AMA / WADA ; www.wada-ama.org ou www.dopage.be) et la liste des produits dopants est revue chaque année. [less ▲]

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See detailConcept et agencement de la lutte contre la "fraude sociale"
Kéfer, Fabienne ULg

in Vermeulen, Geert; Masset, Adrien; Flore, Daniel (Eds.) Comment s'en prendre à la fraude sociale, l'exploitation au travail et la traite des êtres humains : défis et solutions aux niveaux national et européen (2014, May 11)

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See detailInspired bio- nanobiomaterials for tissue engineering and drug delivery systems
Grandfils, Christian ULg

in Vth International Workshop on "NANOPARTICLES, COATINGS AND MICROCONTAINERS: TECHNOLOGY, PROPERTIES, APPLICATIONS" Conference Materials (2014, May 09)

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See detailProjet de recherche appliquée SpatioData : Spécification d’un système participatif pour la réutilisation de données sporadiques sur le bâtiment
Ben Rajeb, Samia ULg; Delfosse, Vincent ULg; Boulanger, Christelle ULg et al

in Proceedings du colloque 01'Design 9 (2014, May 09)

Cet article présente un projet de recherche nommé SpatioData qui a duré trois ans et dont l’objectif visait l’exploitation de nouvelles technologies de l’information et de la communication (TIC) pour ... [more ▼]

Cet article présente un projet de recherche nommé SpatioData qui a duré trois ans et dont l’objectif visait l’exploitation de nouvelles technologies de l’information et de la communication (TIC) pour proposer un outil innovant permettant la réutilisation d’informations liées au bâtiment. Nous montrerons, au travers d’enquêtes et d’interviews, l’importance de faciliter l’accès aux données rattachées à l’historique du bâtiment via un système innovant et intuitif qui permettra à tous les acteurs du secteur de la construction et de la gestion immobilière de trouver et de partager des informations utiles, c’est-à-dire des données spécialisées, contextualisées et spatialisées, en temps réel. Nous listerons des recommandations afin que ces données, qui auraient été perdues ou jetées, puissent être automatiquement mises en relation avec le lieu de l’intervention (géoréférencement) et le type d’intervenant (utilisateur) permettant ainsi de compléter une base de données spatialisées basée sur un modèle de bâtiment spécifique. [less ▲]

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See detailNumerical Simulation of a Conical Shape Made by Single Point Incremental Forming
Velosa De Sena, José ULg; Duchene, Laurent ULg; Habraken, Anne ULg et al

in Incremental sheet forming (2014, May 08)

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See detailEulerian Formulation of the Torque and Drag Problem
Huynen, Alexandre ULg; Detournay, Emmanuel; Denoël, Vincent ULg

in Detournay, Emmanuel; Denoël, Vincent; van de Wouw, Nathan (Eds.) Third International Colloquium on Nonlinear Dynamics and Control of Deep Drilling Systems (2014, May)

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See detailA hybrid human-computer approach for large-scale image-based measurements using web services and machine learning
Marée, Raphaël ULg; Rollus, Loïc ULg; Stevens, Benjamin ULg et al

in Proceedings IEEE International Symposium on Biomedical Imaging (2014, May)

We present a novel methodology combining web-based software development practices, machine learning, and spatial databases for computer-aided quantification of regions of interest (ROIs) in large-scale ... [more ▼]

We present a novel methodology combining web-based software development practices, machine learning, and spatial databases for computer-aided quantification of regions of interest (ROIs) in large-scale imaging data. We describe our main methodological choices, and then illustrate the benefits of the approach (workload reduction, improved precision, scalability, and traceability) on hundreds of whole-slide images of biological tissue slices in cancer research. [less ▲]

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See detailEviter la tour d'ivoire, éviter les allées du pouvoir
Jacquemain, Marc ULg

in Delchambre, Jean-Pierre (Ed.) Le sociologue comme médiateur ? Accords, désaccords et malentendus (2014, May)

L'article s'interroge sur la nature de l'expertise en sciences sociales. En partant de la définition de l'expertise en général par Philippe Roqueplo, on défend que la sociologie ne peut prétendre à une ... [more ▼]

L'article s'interroge sur la nature de l'expertise en sciences sociales. En partant de la définition de l'expertise en général par Philippe Roqueplo, on défend que la sociologie ne peut prétendre à une connaissance scientifique que dans le cadre des questions qu'elle pose elle-même en tant que discipline. Cela ne la dispense pas de répondre aux questions que se pose la société et, en particulier, les pouvoirs publics, mais les réponses n'ont pas le statut de réponses scientifiques. [less ▲]

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See detailQuand une recherche en didactique de l’architecture ambitionne d’alimenter d’une part, une réflexion méthodologique facultaire et, d’autre part, le service à la communauté, voire à la société.
Scheffers, Patricia ULg

in Actes du colloque (2014, May)

Qu’il s’agisse de la directive européenne de 1985 (CE, 1985), du décret « Bologne » (GCFB, 2004) ou du Décret « Paysage » en Communauté Française de Belgique (GCFB, 2013), les textes régissant ... [more ▼]

Qu’il s’agisse de la directive européenne de 1985 (CE, 1985), du décret « Bologne » (GCFB, 2004) ou du Décret « Paysage » en Communauté Française de Belgique (GCFB, 2013), les textes régissant l’enseignement de l’architecture nous exhortent d’ « accompagner les étudiants dans leur rôle de citoyens responsables, capables de contribuer au développement d’une société démocratique, pluraliste et solidaire ». Dix années de travail au sein de bureaux et dix-sept années d’enseignement ont conforté une conscience toujours grandissante des enjeux sociétaux liés à l’exercice de la profession. Ainsi la volonté de participer activement à la formation d’ « architectes-praticiens-réflexifs (Schön, 1987) acteurs d’une société en perpétuelle mutation » s’est matérialisée, fin 2012, par un projet de recherche en didactique de l’architecture. La problématique se situe dans le contexte de la formation initiale des architectes. Elle survient temporellement dans la continuité de la rédaction d'un référentiel facultaire de compétences (Tardif, Fortier, & Préfontaine, 2006). Elle vise la compréhension fine des mécanismes à l’œuvre dans le développement d'une des compétences ciblées : « Instruire une question architecturale • en ayant conscience des enjeux sociétaux contemporains inscrits dans l'Histoire • en faisant preuve de posture réflexive, d’ouverture, d'initiative» Au travers de cette compétence, l’ambition est d’aider les étudiants à construire, non seulement des aptitudes professionnelles, mais, surtout de les encourager à développer des valeurs humanistes et une conscience citoyenne (Rogers, 1984). Elle est de ce point de vue le plus emblématique du référentiel. Quels sont les lieux de développement de la compétence ? Quels mécanismes sous-jacents sont à l’œuvre ? Quels sont les niveaux de développement identifiables au cours du 1er cycle ? Existent-ils des manifestations de transfert au-delà des situations de cours ? Recherche, enseignement et service à la société se retrouvent ainsi intimement liés dans la recherche d’un nouveau centre de gravité… [less ▲]

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See detailExpression of peroxisome-proliferator activated receptor alpha in pituitary tumours
Rotondi, S; Modarelli, A; Rostomyan, Liliya ULg et al

in Endocrine Abstracts (2014, May)

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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 detailApprentissage par renforcement bayésien versus recherche directe de politique hors-ligne en utilisant une distribution a priori: comparaison empirique
Castronovo, Michaël ULg; Ernst, Damien ULg; Fonteneau, Raphaël ULg

in Proceedings des 9èmes Journée Francophones de Planification, Décision et Apprentissage (2014, May)

Cet article aborde le problème de prise de décision séquentielle dans des processus de déci- sion de Markov (MDPs) finis et inconnus. L’absence de connaissance sur le MDP est modélisée sous la forme d’une ... [more ▼]

Cet article aborde le problème de prise de décision séquentielle dans des processus de déci- sion de Markov (MDPs) finis et inconnus. L’absence de connaissance sur le MDP est modélisée sous la forme d’une distribution de probabilité sur un ensemble de MDPs candidats connue a priori. Le cri- tère de performance utilisé est l’espérance de la somme des récompenses actualisées sur une trajectoire infinie. En parallèle du critère d’optimalité, les contraintes liées au temps de calcul sont formalisées rigoureusement. Tout d’abord, une phase « hors-ligne » précédant l’interaction avec le MDP inconnu offre à l’agent la possibilité d’exploiter la distribution a priori pendant un temps limité. Ensuite, durant la phase d’interaction avec le MDP, à chaque pas de temps, l’agent doit prendre une décision dans un laps de temps contraint déterminé. Dans ce contexte, nous comparons deux stratégies de prise de déci- sion : OPPS, une approche récente exploitant essentiellement la phase hors-ligne pour sélectionner une politique dans un ensemble de politiques candidates et BAMCP, une approche récente de planification en-ligne bayésienne. Nous comparons empiriquement ces approches dans un contexte bayésien, en ce sens que nous évaluons leurs performances sur un large ensemble de problèmes tirés selon une distribution de test. A notre connaissance, il s’agit des premiers tests expérimentaux de ce type en apprentissage par renforcement. Nous étudions plusieurs cas de figure en considérant diverses distributions pouvant être utilisées aussi bien en tant que distribution a priori qu’en tant que distribution de test. Les résultats obtenus suggèrent qu’exploiter une distribution a priori durant une phase d’optimisation hors-ligne est un avantage non- négligeable pour des distributions a priori précises et/ou contraintes à de petits budgets temps en-ligne. [less ▲]

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See detailToggling a genetic switch using reinforcement learning
Sootla, Aivar; Strelkowa, Natalja; Ernst, Damien ULg et al

in Proceedings of the 9th French Meeting on Planning, Decision Making and Learning (2014, May)

In this paper, we consider the problem of optimal exogenous control of gene regulatory networks. Our approach consists in adapting an established reinforcement learning algorithm called the fitted Q ... [more ▼]

In this paper, we consider the problem of optimal exogenous control of gene regulatory networks. Our approach consists in adapting an established reinforcement learning algorithm called the fitted Q iteration. This algorithm infers the control law directly from the measurements of the system’s response to external control inputs without the use of a mathematical model of the system. The measurement data set can either be collected from wet-lab experiments or artificially created by computer simulations of dynamical models of the system. The algorithm is applicable to a wide range of biological systems due to its ability to deal with nonlinear and stochastic system dynamics. To illustrate the application of the algorithm to a gene regulatory network, the regulation of the toggle switch system is considered. The control objective of this problem is to drive the concentrations of two specific proteins to a target region in the state space. [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 detailInscrire une vieille tradition d’enseignement de l’architecture dans un dispositif de formation valide en phase avec une société en perpétuelle mutation. Retour sur une recherche-action.
Scheffers, Patricia ULg

in Scheffers, Patricia (Ed.) Actes du colloque (2014, May)

En 2010, la création des facultés d’architecture au sein des universités belges à ajouter à leur mission unique d’enseignement les missions de recherche et de service à la communauté. A Liège, le ... [more ▼]

En 2010, la création des facultés d’architecture au sein des universités belges à ajouter à leur mission unique d’enseignement les missions de recherche et de service à la communauté. A Liège, le changement institutionnel connut une difficulté accrue liée à la fusion de deux institutions jusque-là « concurrentes ». Un lien les unissait cependant : conserver la maîtrise du projet pédagogique spécifique à l’enseignement de l’architecture, une formation visant la conception du projet architectural et sa méthodologie grâce à une pédagogie par projet. En 2011, un groupe d’enseignants praticiens-réflexifs (Schön, 1987) s’est formé pour analyser, questionner le dispositif de formation et le plan d’études résultant des mécanismes administratifs de création de la faculté. Un premier constat de carence est rapidement apparu : l’inexistence d’un socle pédagogique commun définissant les visées de la formation dans un cadre professionnalisant et permettant d’assurer un alignement pédagogique cohérent entre contenus, méthodes et évaluations. Le groupe a dès lors décidé de s’atteler à la construction d’un référentiel de compétences (Tardif, Fortier, & Préfontaine, 2006) comme pierre angulaire de toute réflexion. En juin 2013, le référentiel a été validé par le conseil de faculté. Quels enjeux (politiques, pédagogiques) ont été identifiés ? Comment les liens entre identité professionnelle, formation et profil de compétences professionnelles ont-ils été établis ? (Beckers, 2007). Quelle place occupe ou devrait occuper l’enseignement du projet par le projet dans l’université ? Comment intégrer, en parallèle à une conception « traditionnelle » de pratique architecturale, les dimensions de la recherche et du questionnement théorique ? En quoi cette recherche-action a-t-elle été pour les enseignants d’atelier un véritable levier réflexif ? Ce retour d’expérience permettra de tirer les premières conclusions critiques liées à l’adoption du référentiel et d’identifier les futures actions et/ou réflexions qui s’engageront à court, moyen et long terme. [less ▲]

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See detailToggling a genetic switch using reinforcement learning
Sootla, Aivar; Strelkowa, Natalja; Ernst, Damien ULg et al

in Proceedings of the 9th French Meeting on Planning, Decision Making and Learning (2014, May)

In this paper, we consider the problem of optimal exogenous control of gene regulatory networks. Our approach consists in adapting an established reinforcement learning algorithm called the fitted Q ... [more ▼]

In this paper, we consider the problem of optimal exogenous control of gene regulatory networks. Our approach consists in adapting an established reinforcement learning algorithm called the fitted Q iteration. This algorithm infers the control law directly from the measurements of the system’s response to external control inputs without the use of a mathematical model of the system. The measurement data set can either be collected from wet-lab experiments or artificially created by computer simulations of dynamical models of the system. The algorithm is applicable to a wide range of biological systems due to its ability to deal with nonlinear and stochastic system dynamics. To illustrate the application of the algorithm to a gene regulatory network, the regulation of the toggle switch system is considered. The control objective of this problem is to drive the concentrations of two specific proteins to a target region in the state space. [less ▲]

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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 detailEstimating the revenues of a hydrogen-based high-capacity storage device: methodology and results
François-Lavet, Vincent ULg; Fonteneau, Raphaël ULg; Ernst, Damien ULg

in Proceedings des 9èmes Journée Francophones de Planification, Décision et Apprentissage (2014, May)

This paper proposes a methodology to estimate the maximum revenue that can be generated by a company that operates a high-capacity storage device to buy or sell electricity on the day-ahead electricity ... [more ▼]

This paper proposes a methodology to estimate the maximum revenue that can be generated by a company that operates a high-capacity storage device to buy or sell electricity on the day-ahead electricity market. The methodology exploits the Dynamic Programming (DP) principle and is specified for hydrogen-based storage devices that use electrolysis to produce hydrogen and fuel cells to generate electricity from hydrogen. Experimental results are generated using historical data of energy prices on the Belgian market. They show how the storage capacity and other parameters of the storage device influence the optimal revenue. The main conclusion drawn from the experiments is that it may be interesting to invest in large storage tanks to exploit the inter-seasonal price fluctuations of electricity. [less ▲]

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See detailGestion active d’un réseau de distribution d’électricité : formulation du problème et benchmark
Gemine, Quentin ULg; Ernst, Damien ULg; Cornélusse, Bertrand ULg

in Proceedings des 9èmes Journées Francophones de Planification, Décision et Apprentissage (2014, May)

Afin d’opérer un réseau de distribution d’électricité de manière fiable et efficace, c’est-à-dire de respecter les contraintes physiques tout en évitant des coûts de renforcement prohibitifs, il devient ... [more ▼]

Afin d’opérer un réseau de distribution d’électricité de manière fiable et efficace, c’est-à-dire de respecter les contraintes physiques tout en évitant des coûts de renforcement prohibitifs, il devient nécessaire de recourir à des stratégies de gestion active du réseau. Ces stratégies, rendues nécessaires notamment par l’essor de la production distribuée, reposent sur des politiques de contrôle à court-terme du niveau de puissance des dispositifs producteurs ou consommateurs d’électricité. Alors qu’une solution simple consisterait à moduler à la baisse la production des générateurs, il paraît néan- moins plus intéressant de déplacer la consommation aux moments adéquats afin d’exploiter au mieux les sources d’énergie renouvelables sur lesquelles reposent généralement ces générateurs. Un tel moyen de contrôle introduit néanmoins un couplage temporel au problème, menant à un problème d’optimisation non-linéaire, séquentiel sous incertitude et à variables mixtes. Afin de favoriser la recherche dans ce domaine très complexe, nous proposons une formalisation générique du problème de ges- tion active d’un réseau de distribution moyenne tension (MT). Plus spécifiquement, cette formalisa- tion se présente sous la forme d’un processus de décision markovien. Dans cette article, nous pré- sentons également une spécification de ce modèle décisionnel à un réseau de 75 noeuds et pour un ensemble de services de modulation donnés. L’instance de test qui en résulte est disponible à l’adresse http://www.montefiore.ulg.ac.be/~anm/ et a pour objectif de mesurer et de comparer les performances des techniques de résolution qui seront développées. [less ▲]

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See detailTest equipments for characterizing the behavior of materials, bearings and dynamic seals in cryogenic fluid environments
Bozet, Jean-Luc ULg; Servais, Christophe ULg; Duquenne, Marc ULg et al

in Space Propulsion 2014 (2014, May)

Test rigs available at the cryogenic test site of the University of Liège concern quite delicate high rotational speed components of cryogenic rocket engines. That is to say bearings and dynamic seals ... [more ▼]

Test rigs available at the cryogenic test site of the University of Liège concern quite delicate high rotational speed components of cryogenic rocket engines. That is to say bearings and dynamic seals. These rigs gave successfully important results for the understanding and the improvement of the running of the so called components. Until now the test zone is equipped for handling liquid oxygen and liquid nitrogen. [less ▲]

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See detailApplication of multiple-point geostatistics on modelling pumping tests and tracer tests in heterogeneous environments with complex geological structures
Huysmans, Marijke; Dassargues, Alain ULg

in Geophysical Research Abstracts (2014, April 28)

In heterogeneous environments with complex geological structures, analysis of pumping and tracer tests is often problematic. Standard interpretation methods do not account for heterogeneity or simulate ... [more ▼]

In heterogeneous environments with complex geological structures, analysis of pumping and tracer tests is often problematic. Standard interpretation methods do not account for heterogeneity or simulate this heterogeneity introducing empirical zonation of the calibrated parameters or using variogram-based geostatistical techniques that are often not able to describe realistic heterogeneity in complex geological environments where e.g. sedimentary structures, multi-facies deposits, structures with large connectivity or curvi-linear structures can be present. Multiple-point geostatistics aims to overcome the limitations of the variogram and can be applied in different research domains to simulate heterogeneity in complex environments. In this project, multiple-point geostatistics is applied to the interpretation of pumping tests and a tracer test in an actual case of a sandy heterogeneous aquifer. This study allows to deduce the main advantages and disadvantages of this technique compared to variogram-based techniques for interpretation of pumping tests and tracer tests. A pumping test and a tracer test were performed in the same sandbar deposit consisting of cross-bedded units composed of materials with different grain sizes and hydraulic conductivities. The pumping test and the tracer test are analyzed with a local 3D groundwater model in which fine-scale sedimentary heterogeneity is modelled using multiple-point geostatistics. To reduce CPU and RAM requirements of the multiple-point geostatistical simulation steps, edge properties indicating the presence of irregularly-shaped surfaces are directly simulated. Results show that for the pumping test as well as for the tracer test, incorporating heterogeneity results in a better fit between observed and calculated drawdowns/concentrations. The improvement of the fit is however not as large as expected. In this paper, the reasons for these somewhat unsatisfactory results are explored and recommendations for future applications of multiple-point geostatistics on pumping tests and tracer tests are formulated. [less ▲]

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See detailThermal tracer tests for characterizing a shallow alluvial aquifer
Wildemeersch, Samuel ULg; Klepikova, Maria ULg; Jamin, Pierre ULg et al

in Geophysical Research Abstracts (2014, April 28)

Using heat as an active tracer in different types of aquifers is a topic of increasing interest [e.g. Vandenbohede et al.; 2008, Wagner et al., 2013; Read et al., 2013]. In this study, we investigate the ... [more ▼]

Using heat as an active tracer in different types of aquifers is a topic of increasing interest [e.g. Vandenbohede et al.; 2008, Wagner et al., 2013; Read et al., 2013]. In this study, we investigate the potential interest of coupling heat and solute tracer tests for characterization of a shallow alluvial aquifer. A thermal tracer test was conducted in the alluvial aquifer of the Meuse River, Belgium. The tracing experiment consisted in simultaneously injecting heated water and a dye tracer in a piezometer and monitoring the evolution of groundwater temperature and tracer concentration in the recovery well and in nine monitoring wells located according to three transects with regards to the main groundwater flow direction. The breakthrough curves measured in the recovery well showed that heat transfer in the alluvial aquifer is slower and more dispersive than solute transport. Recovery is very low for heat while in the same time it is measured as relatively high for the solute tracer. This is due to the fact that heat diffusion is larger than molecular diffusion, implying that exchange between groundwater and the porous medium matrix is far more significant for heat than for solute tracers. Temperature and concentrations in the recovery well are then used for estimating the specific heat capacity with the energy balance approach and the estimated value is found to be consistent with those found in the literature. Temperature breakthrough curves in other piezometers are contrasted with what would be expected in an ideal layered aquifer. They reveal strongly unequal lateral and vertical components of the transport mechanisms. By means of a numerical heat transport model, we provide a preliminary interpretation of these temperature breakthrough curves. Furthermore, these data could be included in the calibration of a complex heat transfer model for estimating the entire set of heat transfer parameters and their spatial distribution by inverse modeling. [less ▲]

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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 detailMachine learning techniques to assess the performance of a gait analysis system
Pierard, Sébastien ULg; Phan-Ba, Rémy; Van Droogenbroeck, Marc ULg

in European Symposium on Artificial Neural Networks, Computational Intelligence and Machine Learning (ESANN) (2014, April 24)

This paper presents a methodology based on machine learning techniques to assess the performance of a system measuring the trajectories of the lower limbs extremities for the follow-up of patients with ... [more ▼]

This paper presents a methodology based on machine learning techniques to assess the performance of a system measuring the trajectories of the lower limbs extremities for the follow-up of patients with multiple sclerosis. We show how we have established, with the help of machine learning, four important properties about this system: (1) an automated analysis of gait characteristics provides an improved analysis with respect to that of a human expert, (2) after learning, the gait characteristics provided by this system are valuable compared to measures taken by stopwatches, as used in the standardized tests, (3) the motion of the lower limbs extremities contains a lot of useful information about the gait, even if it is only a small part of the body motion, (4) a measurement system combined with a machine learning tool is sensitive to intra-subject modifications of the walking pattern. [less ▲]

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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)

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See detailLa Belgique, un pays complexe
Hermans, Michel ULg

in Perdigon, Marie-France (Ed.) Actes des VIIème entretiens sur l'identité européenne (2014, April 19)

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See detailAtrial Natriuretic Peptide in cardiac horses
Leroux, Aurélia ULg; Al-Haidar, Ali; Remy, Benoît ULg et al

in Voorjaarsdagen Proceedings (2014, April 17)

Background: Natriuretic peptides are cardiac biomarkers that have been shown to have high potential for diagnosis, prognosis, and guidance of treatment in human and small animal cardiology. However, their ... [more ▼]

Background: Natriuretic peptides are cardiac biomarkers that have been shown to have high potential for diagnosis, prognosis, and guidance of treatment in human and small animal cardiology. However, their diagnostic and prognosis value in the equine species has only been studied in a limited number of cases. Objective: To investigate the plasma atrial natriuretic peptide concentration (ANPPl) in a large group of horses with various degrees of valvular regurgitation (VR) and heart failure (HF). Animals: Ninety-one horses, admitted at the equine teaching hospital of the University of Liege, and with no, mild, moderate or severe VR and presenting various stages of HF, according to human and canine grading system (A: no VR, B1: asymptomatic VR without cardiac remodelling, B2: asymptomatic VR with cardiac remodelling, C: symptomatic VR). Methods: All horses underwent clinical and Doppler echocardiographic examination, which allowed determining the presence, nature, and severity of VR, and the HF stage. The ANPPl was measured using a commercially available human RIA test. The mean values of body weight, age, ANPPl and each echocardiographic parameter were compared between horses in stage A, B1, B2 or C of HF and between horses with no, mild, moderate or severe VR, using a one-way ANOVA test. Then, correlations between ANPPl and each echocardiographic parameter were assessed using a Pearson’s product-moment analysis. Results: Horses with severe and moderate VR had significantly higher ANPPl than horses with mild or no VR. ANPPl was significantly higher in horses at stage B2 and C of HF than horses at stage A and B1. Moreover, ANPPl was significantly correlated with most of the measured echocardiographic variables. This correlation was especially strong with the left atrial diameter and its percentage of dilation. Conclusions and Clinical Importance: Those results suggest that ANPPl in horses suffering from VR could have a high diagnostic value of HF, especially in horses with tricuspid or mitral insufficiency and with enlargement or dysfunction of the atria. [less ▲]

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See detailOptimisation de la rétention des produits phytosanitaires sur une surface superhydrophobe
Ouled Taleb Salah, Sofiene ULg; Massinon, Mathieu ULg; Schiffers, Bruno ULg et al

in Journée Nationale sur la valorisation des Résultats de la Recherche dans le Domaine des Grandes Cultures (2014, April 17)

La protection des cultures est principalement réalisée en Tunisie par l’application de bouillies phytosanitaires à base d’eau. Au niveau de l’impact des gouttes sur le feuillage, trois types de ... [more ▼]

La protection des cultures est principalement réalisée en Tunisie par l’application de bouillies phytosanitaires à base d’eau. Au niveau de l’impact des gouttes sur le feuillage, trois types de comportement sont observés, à savoir l’adhésion, le rebond et la fragmentation. Ces types d’impact affectent la rétention par le feuillage et dépendent de la taille et de la vitesse des gouttes, des propriétés physico-chimiques de la bouillie et de la mouillabilité des surfaces foliaires. Une technique d’imagerie rapide a permis d’évaluer la pertinence de l’utilisation d’adjuvants tensio-actifs en vue d’améliorer la rétention en agissant sur le type d’impact. Des essais de rétention sur feuilles de vulpin, surface très peu mouillables ou superhydrophobe, montrent que l’ajout d’un adjuvant 0,1 %v/v dans l’eau contribue à l’amélioration des dépôts. La proportion d’adhésion a augmenté alors que celle du rebond a diminué. Cette technique en laboratoire est un outil efficace pour évaluer les pratiques culturales des agriculteurs et de fournir des conseils et recommandations pratiques en fonction des cibles. [less ▲]

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See detailPIONIER : A Four Telescope VLTI Instrument
Lazareff, B.; Le Bouquin, J.-L.; Berger, J.-P. et al

in Surdej, Jean; Le Coroller, Hervé; Arnold, Luc (Eds.) Improving the Performances of Current Optical Interferometers & Future Designs (2014, April 01)

Pionier is a guest instrument, the first four-telescope recombiner at ESO's VLTI. We discuss salient design features and illustrate selected scientific results from the fi

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See detailObserving the Sun with micro-interferometric devices: a didactic experiment
Defrere, D.; Absil, Olivier ULg; Hanot, C. et al

in Surdej, Jean; Le Coroller, Hervé; Arnold, Luc (Eds.) Improving the Performances of Current Optical Interferometers & Future Designs (2014, April 01)

Measuring the angular diameter of celestial bodies has long been the main purpose of stellar interferometry and was its historical motivation. Nowadays, stellar interferometry is widely used for various ... [more ▼]

Measuring the angular diameter of celestial bodies has long been the main purpose of stellar interferometry and was its historical motivation. Nowadays, stellar interferometry is widely used for various other scientific purposes that require very high angular resolution measurements. In terms of angular spatial scales probed, o [less ▲]

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See detailOptimized Waveform Relaxation Methods for Modeling Electromagnetic Field-Circuit Problems
Nshimiyimana, Jean de Dieu ULg; Plumier, Frédéric ULg; Dular, Patrick ULg et al

in Proceedings of Sixteenth Biennal IEEE Conference on Electromagnetic Field Computation (2014, April)

The convergence of classical and optimized waveform relaxation methods is compared for the simulation of field-circuit problems, where a finite element solver is used for the solution of the field problem ... [more ▼]

The convergence of classical and optimized waveform relaxation methods is compared for the simulation of field-circuit problems, where a finite element solver is used for the solution of the field problem and a circuit simulator is used for the electronic circuit. [less ▲]

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See detailDynamics of a Strongly Nonlinear Spacecraft Structure Part II: Modal Analysis
Renson, Ludovic ULg; Noël, Jean-Philippe ULg; Kerschen, Gaëtan ULg

in Proceedings of the 13th European Conference on Spacecraft Structures, Materials & Environmental Testing (2014, April)

The present paper investigates the dynamics of a real-life spacecraft structure possessing a strongly nonlinear component with multiple mechanical stops. A full-scale finite element model is built for ... [more ▼]

The present paper investigates the dynamics of a real-life spacecraft structure possessing a strongly nonlinear component with multiple mechanical stops. A full-scale finite element model is built for gaining additional insight into the nonlinear dynamics that was observed experimentally in a companion paper (Part I). To this end, advanced techniques and theoretical concepts such as numerical continuation and nonlinear normal modes are exploited. [less ▲]

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See detailThe Tale of Sinuhe: History of a literary text
Winand, Jean ULg

in Hays, Harold; Feder, Frank; Morenz, Ludwig (Eds.) Interpretations of Sinuhe (2014, April)

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See detailCharacterization of printed circuit boards from scrap printers
Silvas, Flávia; de Moraes, Viviane; Bortolini, Guilherme et al

in Yurko, James; Zhang, Lifeng; Allanore, Antoine (Eds.) Proceedings TMS 2014 143rd ANNUAL MEETING & EXHIBITION (2014, April)

Printed circuit boards (PCB) are particularly problematic to recycle because of the heterogeneous mix of organic materials, metals, and glass fiber. PCBs are found in almost every electroelectronic ... [more ▼]

Printed circuit boards (PCB) are particularly problematic to recycle because of the heterogeneous mix of organic materials, metals, and glass fiber. PCBs are found in almost every electroelectronic equipment and their recycling process involves a pre-treatment to separate the products which contain targeted metals. In this work, a physical processing involving sequential shredding and hammer milling were used to obtain a comminuted sample from scrap printers PCBs. The thus prepared sample was analyzed for particle size distribution and by optical microscopy as well was subjected to pyrolysis, leachabilty and chemical composition determination by XRF. The metals concentration was determined by ICP and AAS. The PCBs have been also analyzed by SEM-EDS (micro-analysis and X-ray mapping). The results show that the studied PCBs are lead free, multilayer with 4 copper layers, have 45% of metals and the copper is present in significantly higher concentration than the rest of the metals. [less ▲]

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See detailDynamics of a Strongly Nonlinear Spacecraft Structure Part I: Experimental Identification
Noël, Jean-Philippe ULg; Renson, Ludovic ULg; Kerschen, Gaëtan ULg

in Proceedings of the 13th European Conference on Spacecraft Structures, Materials and Environmental Testing (2014, April)

The present paper addresses the identification of a real-life spacecraft structure possessing a strongly nonlinear component with multiple mechanical stops. The complete identification procedure, from ... [more ▼]

The present paper addresses the identification of a real-life spacecraft structure possessing a strongly nonlinear component with multiple mechanical stops. The complete identification procedure, from nonlinearity detection and characterization to parameter estimation, is carried out based upon experimental sine-sweep data collected during a classical spacecraft qualification campaign. [less ▲]

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