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See detailGenetic variation of Viola calaminaria, an endemic metallophyte
Bizoux, Jean-Philippe ULg; Mahy, Grégory ULg

in Proceedings of the GfÖ: Lanscapes, ecosystems and populations: dynamics, functions and conservation (2005)

The zinc violet, Viola calaminaria (DC) Lej., is a rare threatened species in Belgium which is endemic to metalliferous sites. Yours aims were to assess the genetic structure of the species at the scale ... [more ▼]

The zinc violet, Viola calaminaria (DC) Lej., is a rare threatened species in Belgium which is endemic to metalliferous sites. Yours aims were to assess the genetic structure of the species at the scale of its distribution range, including differentiation with related taxa Viola guesphalica and to examine the influence of population size and recent colonisation events on population genetic structure in order to identify conservation priorities. The analysis of genetic variation (Amova) showed a strong population differentiation (Fst = 0.26) with a regional group differentiation. The V. guestfalica population exhibits the larger differentiation (Fst = 0.19). The levels of population genetic diversity (Hs) varied from 0.21 to 0.29. Mean genetic differentiation among ancient populations (Fst =0.26) is higher than genetic differentiation among recent populations (Fst =0.18) while any difference appears on genetic diversity. This strong population differentiation suggests a low gene flow between populations but sufficient within population to maintain high level of diversity. For management, the result implies a hierarchical conservation strategy including small population. New populations had as much genetically importance than old populations. No foundation effects were detected in the recent populations. These populations probably result from multiple colonization effects from more than one source population. Finally, even if some V. calaminaria populations exhibit a similar level of genetic differentiation of V. guestfalica population, this one appeared as a particular genetic pool. [less ▲]

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See detailClosed-form dual perturb and combine for tree-based models
Geurts, Pierre ULg; Wehenkel, Louis ULg

in Proceedings of the International Conference on Machine Learning (ICML 2005) (2005)

This paper studies the aggregation of predictions made by tree-based models for several perturbed versions of the attribute vector of a test case. A closed-form approximation of this scheme combined with ... [more ▼]

This paper studies the aggregation of predictions made by tree-based models for several perturbed versions of the attribute vector of a test case. A closed-form approximation of this scheme combined with cross-validation to tune the level of perturbation is proposed. This yields soft-tree models in a parameter free way, and reserves their interpretability. Empirical evaluations, on classification and regression problems, show that accuracy and bias/variance tradeoff are improved significantly at the price of an acceptable computational overhead. The method is further compared and combined with tree bagging. [less ▲]

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See detailA lattice model for BNE and RBNE
Ludewig, François ULg; Vandewalle, Nicolas ULg

in Powders and Grains 2005 (2005)

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See detailSuspicion d’insuffisance hépatique chez le cheval: quels examens complémentaires utiliser sur le terrain?
Amory, Hélène ULg; Lopez, Diego; Busoni, Valeria ULg

in Proceedings du 2ème congrès de biologie clinique (2005)

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See detailModélisation de la fissuration par fatigue des connexions poutres-colonnes de grands bâtiments en armature en acier lors de tremblements de terre
Lequesne, Cédric ULg; Plumier, André ULg; Habraken, Anne ULg

in Proceedings of the XVIIème congrès français de mécanique (CFM 2005) (2005)

Many steel frame buildings have cracked in beam-to-column connections during earthquakes. To determine the place and the moment of the crack initiation, a model of continuous damage is used in a finite ... [more ▼]

Many steel frame buildings have cracked in beam-to-column connections during earthquakes. To determine the place and the moment of the crack initiation, a model of continuous damage is used in a finite element computation. Cohesive zones model predicts the propagation. The residual stresses are evaluated before. [less ▲]

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See detailAnalyse inverse d’une courbe pressiométrique par algorithme génétique
Levasseur, Séverine ULg; Malécot, Yann; Boulon, Marc et al

in Gambin, Michel; Magnan, Jean-Pierre; Mestat, Philippe (Eds.) ISP5 - Pressio 2005 - Volume 1 (2005)

Cet article est consacré à l’identification des paramètres constitutifs d’un modèle de Mohr-Coulomb à partir d’un essai pressiométrique. Pour minimiser l’écart entre le résultat de l’essai et sa ... [more ▼]

Cet article est consacré à l’identification des paramètres constitutifs d’un modèle de Mohr-Coulomb à partir d’un essai pressiométrique. Pour minimiser l’écart entre le résultat de l’essai et sa simulation numérique, une optimisation par algorithme génétique est proposée. On montre qu’il semble difficile d’identifier simultanément un module de déformation et un angle de frottement à partir d’une seule courbe pressiométrique [less ▲]

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See detailDSM from SPOT5-HRS images: extraction and validation
Cornet, Yves ULg; Grevesse, J.; Binard, Marc ULg et al

in Jacobsen, K.; Goossens, Rudi; Winkler, P. (Eds.) Proceding of the EARSeL Workshop 3D-Remote Sensing: Porto, June 10 - 11, 2005 (2005)

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See detailLa carte des territoires paysagers, pour une meilleure connaissance des paysages wallons
Kummert, Magali; Droeven, Emilie ULg; Feltz, Claude

in Quatrièmes rencontres de la Conférence Permanente du Développement Territorial.Territoire, urbanisation et paysages (2005)

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See detailAdministration par inhalation de marbofloxacine chez le cheval: effets sur la fonction respiratoire - concentrations obtenues dans le liquide pulmonaire par rapport ) la voie IV
Art, Tatiana ULg; De Moffarts, Brieuc; Van Erck, Emmanuelle et al

in Proceedings : Journées AVEF (2005)

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See detailDifferent mechanoregulatory models predict different patterns of tissue differentiation
Geris, Liesbet ULg; Van Oosterwyck, Hans; Duyck, Joke et al

in Middleton, J.; Jones, M. L.; Shrive, N. (Eds.) Proceedings of the 6th international symposium on Computer Methods in Biomechanics and Biomedical Engineering (2005)

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See detailAdvanced particle characterization for improved understanding of cold spray coating quality
Pirard, Eric ULg; Campana, Florent; Janssen, Jean-Pierre

in Pawlowski, Lech (Ed.) 2e Rencontres Int. Projection Thermique (2005)

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See detailSegment and combine approach for Biological Sequence Classification
Geurts, Pierre ULg; Blanco Cuesta, Antia; Wehenkel, Louis ULg

in Proc. IEEE Symposium on Computational Intelligence in Bioinformatics and Computational Biology (CIBCB 2005) (2005)

This paper presents a new algorithm based on the segment and combine paradigm, for automatic classification of biological sequences. It classifies sequences by aggregating the information about their ... [more ▼]

This paper presents a new algorithm based on the segment and combine paradigm, for automatic classification of biological sequences. It classifies sequences by aggregating the information about their subsequences predicted by a classifier derived by machine learning from a random sample of training subsequences. This generic approach is combined with decision tree based ensemble methods, scalable both with respect to sample size and vocabulary size. The method is applied to three families of problems: DNA sequence recognition, splice junction detection, and gene regulon prediction. With respect to standard approaches based on n-grams, it appears competitive in terms of accuracy, flexibility, and scalability. The paper also highlights the possibility to exploit the resulting models to identify interpretable patterns specific of a given class of biological sequences. [less ▲]

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See detailRespiratory Distress Syndrome in full-term newborn calves: clinical, laboratory and post-mortem findings
Rollin, Frédéric ULg; Danlois, Fabien; Aliaoui, Hamani et al

in Proceedings of the 23rd ACVIM (2005)

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See detailOptimisation of hydroelectric power stations operations with WOLF package
Erpicum, Sébastien ULg; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Repp, K.; Westeren, T.; Sandlund, O. T. (Eds.) et al Proceedings of the 5th International Conference on Hydropower - The backbone of sustainable energy supply (2005)

For years, original free-surface flow solvers have been developed and continuously improved by the Laboratory of Applied Hydrodynamics and Hydraulic Constructions (HACH) at the University of Liège. The ... [more ▼]

For years, original free-surface flow solvers have been developed and continuously improved by the Laboratory of Applied Hydrodynamics and Hydraulic Constructions (HACH) at the University of Liège. The resulting fully integrated WOLF computation package allows engineers to accurately study a very wide range of various free surface flows, from hydrological runoff (WOLF HYDRO) and river propagation (WOLF 1D) to extreme erosive flows on realistic mobile topography (WOLF 2D), such as gradual dam breaching processes. All the finite volume models, process oriented, use efficient and original numerical methods to solve free surface flows equations. Each code handles general multiblock meshes, dealing with natural topography, dry and wet cells and mobile bed simultaneously, for any unsteady situation with mixed regimes and moving hydraulic jumps. The interactive and unique user-interface, with high performance pre- and post-processing, allows monitoring 3-D large-scale runs graphically while they proceed, as well as generating 3D videos. In addition, powerful optimisation capabilities based on the Genetic Algorithms technique (WOLF AG) are implemented within WOLF, interconnecting all the package components. An efficient tool is thus available to calibrate physical parameters in any of the models and to manage any problem of optimisation with the different solvers. In this paper, the numerical optimisation process of the system of hydroelectric power stations installed on a 60 km long section of the rivers Amblève and Warche in Belgium is presented in detail. The river network is modelled in quasi-2D using real natural topographic data on almost 1,100 finite volumes. In a first step, the hydrological balance is closed using the solver WOLF HYDRO. Roughness coefficients are calibrated from water level and discharge field measurements. Secondly, the hydroelectric production is maximised by an automatic calibration of the parameters of the hydrograph released in the network at the upstream dam. This approach leads to a substantial gain in hydroelectric production, brings significant financial benefits and deals with all management and security criteria of the river network. [less ▲]

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See detailRandom Subwindows for Robust Image Classification
Marée, Raphaël ULg; Geurts, Pierre ULg; Piater, Justus ULg et al

in Proceedings of the IEEE International Conference on Computer Vision and Pattern Recognition (CVPR 2005) (2005)

We present a novel, generic image classification method based on a recent machine learning algorithm (ensembles of extremely randomized decision trees). Images are classified using randomly extracted ... [more ▼]

We present a novel, generic image classification method based on a recent machine learning algorithm (ensembles of extremely randomized decision trees). Images are classified using randomly extracted subwindows that are suitably normalized to yield robustness to certain image transformations. Our method is evaluated on four very different, publicly available datasets (COIL-100, ZuBuD, ETH-80, WANG). Our results show that our automatic approach is generic and robust to illumination, scale, and viewpoint changes. An extension of the method is proposed to improve its robustness with respect to rotation changes. [less ▲]

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See detailIs bounce juggling easier in a parabolic billiard than in a wedge
Chang, Dong Eui; Ronsse, Renaud; Sepulchre, Rodolphe ULg

in Proceedings of the 5th Euromech nonlinear dynamics conference (2005)

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See detailOscillator Models and Collective Motion: Splay State Stabilization of Self-Propelled Particles
Paley, Derek; Leonard, Naomi; Sepulchre, Rodolphe ULg

in Proceedings of the 44th IEEE Conference on Decision and Control and European Control Conference (2005)

This paper presents a Lyapunov design for the stabilization of collective motion in a planar kinematic model of N particles moving at constant speed. We derive a control law that achieves asymptotic ... [more ▼]

This paper presents a Lyapunov design for the stabilization of collective motion in a planar kinematic model of N particles moving at constant speed. We derive a control law that achieves asymptotic stability of the splay state formation, characterized by uniform rotation of N evenly spaced particles on a circle. In designing the control law, the particle headings are treated as a system of coupled phase oscillators. The coupling function which exponentially stabilizes the splay state of particle phases is combined with a decentralized beacon control law that stabilizes circular motion of the particles in the splay state formation around the center of mass of the group. [less ▲]

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See detailDecision Trees and Random Subwindows for Object Recognition
Marée, Raphaël ULg; Geurts, Pierre ULg; Piater, Justus ULg et al

in ICML workshop on Machine Learning Techniques for Processing Multimedia Content (MLMM2005) (2005)

In this paper, we compare five tree-based machine learning methods within a recent generic image classification framework based on random extraction and classification of subwindows. We evaluate them on ... [more ▼]

In this paper, we compare five tree-based machine learning methods within a recent generic image classification framework based on random extraction and classification of subwindows. We evaluate them on three publicly available object recognition datasets (COIL-100, ETH-80, and ZuBuD). Our comparison shows that this general and conceptually simple framework yields good results when combined with ensemble of decision trees, especially when using Tree Boosting or Extra-Trees. The latter is also particularly attractive in terms of computational efficiency. [less ▲]

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See detailWilliam Cliff, de la rue Marché-au-charbon à America
Demoulin, Laurent ULg

in Russo, Adelaide; Harel, Simon (Eds.) Lieux propices: l'énonciation des lieux/le lieu de l'énonciation dans les contextes francophones interculturels (2005)

L'oeuvre du poète belge William Cliff est souvent incarnée dans un lieu, si elle n'est pas la traduction des déplacements d'un marcheur infatigable. Ces caractéristiques thématiques croisent les ... [more ▼]

L'oeuvre du poète belge William Cliff est souvent incarnée dans un lieu, si elle n'est pas la traduction des déplacements d'un marcheur infatigable. Ces caractéristiques thématiques croisent les caractéristiques formelles de cette poésie qui fait un usage particulier de la versification. [less ▲]

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See detailTraitements conservateurs de la lombalgie.
TOMASELLA, Marco ULg

in Abstract Book of 2nd International Symposium of the Belgium Back Society. Prise en charge interdisciplinaire de la lombalgie. (2004, December 11)

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See detailBinaries in the Hipparcos data: Keep digging, I. Search for binaries without `a priori' knowledge of their orbital elements: Application to barium stars
Jorissen, A.; Jancart, Sylvie ULg; Pourbaix, D.

in Hensberge, H; Pavlovski, K.; Hilditch, R.W. (Eds.) Spectroscopically and Spatially Resolving the Components of the Close Binary Stars (2004, December 01)

This work makes use of Hipparcos data to test the algorithms of (i) binary detection and (ii) orbital-parameters determination, which could possibly be used in the GAIA pipeline. The first item is ... [more ▼]

This work makes use of Hipparcos data to test the algorithms of (i) binary detection and (ii) orbital-parameters determination, which could possibly be used in the GAIA pipeline. The first item is addressed in this paper, whereas the second one is addressed in a companion paper by Pourbaix, Jancart, & Jorissen (2004, this volume). Here we test the ability of the algorithm to detect binaries from scratch, i.e., from the astrometric data without any a priori knowledge of the orbital elements. The Hipparcos Intermediate Astrometric Data of a complete sample of 163 barium stars (supposed to be all members of binary systems from theoretical considerations) are used as a test bench. When \varpi > 5 mas and P < 4000 d, the binary detection rate is close to 100%, but it falls to 22% when considering the whole sample, because many barium stars have small parallaxes or very long periods. [less ▲]

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See detailBinaries in the Hipparcos data: keep digging II. Modeling the IAD of known spectroscopic systems
Pourbaix, D.; Jancart, Sylvie ULg; Jorissen, A.

in Hensberge, H.; Pavlovski, K.; Hilditch, R. W. (Eds.) Spectroscopically and Spatially Resolving the Components of the Close Binary Stars (2004, December 01)

We reprocess the Hipparcos Intermediate Astrometric Data of know spectroscopic binaries (retrived from the 9th catalogue of spectroscopic binary orbits, http://sb9.astro.ulb.ac.be) to see whether the ... [more ▼]

We reprocess the Hipparcos Intermediate Astrometric Data of know spectroscopic binaries (retrived from the 9th catalogue of spectroscopic binary orbits, http://sb9.astro.ulb.ac.be) to see whether the orbital inclination, and thus the mass of the secondary, can be derived. Several statistical tests (Pourbaix & Arenou 2001) are used to ensure the reliability of the fit. About 70 systems (originally processed as single stars) out of 863 benefit from the orbital model. [less ▲]

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See detailThe PEGASE project: characterisation of "Pegasi planets" and Brown Dwarfs
Baudoz, P.; Rouan, D.; Schneider, J. et al

in Combes, F.; Barret, D.; Contini, T. (Eds.) et al SF2A-2004: Semaine de l'Astrophysique Francaise (2004, December 01)

I will present the PEGASE project proposed within the framework of the CNES call for idea on flights in formation. This ambitious project, gathering a dozen laboratories, proposes an interferometry ... [more ▼]

I will present the PEGASE project proposed within the framework of the CNES call for idea on flights in formation. This ambitious project, gathering a dozen laboratories, proposes an interferometry mission in infrared I(1.5 to 6 µm) with spectroscopic capabilities. The bases of the interferometer will reach up to 500m, giving to PEGASE a resolution higher than the milli-arcsecond. The interferometric recombination includes a very simple mode, measurement of the visibility by excursion of the optical path difference and a mode in black fringe or nulling. The very high angular resolution of the instrument and high dynamical range with the nulling mode will allow to consider exciting scientific objectives: the characterization of Pegasids or hot Jupiters, the study of the internal structure and the atmospheres of brown dwarfs and the analysis of the internal areas of proto-planetary disks. I will first of all describe the basic configuration of the mission and will show that its simplicity ensures the feasibility of the project. I will explain then the relevance of such an instrument for the characterization of Pegasids. I will detail finally the various possible technical options to be attached to the initial version, in order to increase the effectiveness of the mission and to extend its scientific objectives. [less ▲]

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See detailLimits for the application of spectroscopic mode ID methods
Zima, W.; Kolenberg, K.; Briquet, Maryline ULg et al

in IAU Symposium, No. 224, The A-Star Puzzle, held in Poprad, Slovakia, July 8-13, 2004. (2004, December 01)

Spectroscopic mode identification techiques, which monitor intensity variations across an absorption line, provide the possibility of determining the quantum numbers l and m, the inclination and the ... [more ▼]

Spectroscopic mode identification techiques, which monitor intensity variations across an absorption line, provide the possibility of determining the quantum numbers l and m, the inclination and the intrinsic pulsation amplitude of a star. Of course, the uncertainties of the mode identification are dependent on the quality of the observations and the identification method applied. We have focused on the Pixel-by-pixel method/Direct line profile fitting (Mantegazza 2000) and the Moment method (Balona 1987, Briquet & Aerts 2003) for pinpointing mode parameters and tested the impact of various observational effects and stellar properties on the identification. [less ▲]

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See detailA search for radial magnetic field gradients in Ap atmospheres
Nesvacil, N.; Hubrig, S.; Jehin, Emmanuel ULg et al

in Zverko, J. (Ed.) The A-Star Puzzle (2004, December 01)

For the first time the possible presence of radial gradients of magnetic fields in the atmospheres of three magnetic Ap stars has been critically examined by measurements of the mean magnetic field ... [more ▼]

For the first time the possible presence of radial gradients of magnetic fields in the atmospheres of three magnetic Ap stars has been critically examined by measurements of the mean magnetic field modulus from spectral lines resolved into magnetically split components lying on the different sides of the Balmer jump. A number of useful diagnostic lines below and above the Balmer discontinuity, only slightly affected by blends, with simple doublet and triplet Zeeman pattern have been identified from the comparison between synthetic spectra computed with the SYNTHMAG code and the high resolution and S/N spectra obtained in unpolarized light with the ESO-VLT UVES spectrograph. For all three stars of our sample, HD 965, HD 116114 and 33 Lib (HD 137949), an increase of the magnetic field strength of the order of a few hundred Gauss has been detected bluewards of the Balmer discontinuity. These results should be taken into account in future modelling of the geometric structure of Ap star magnetic fields and the determination of the chemical abundances in Ap stars with strong magnetic fields. [less ▲]

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See detailCollective Motion: Bistability and Trajectory Tracking
Paley, Derek; Leonard, Naomi; Sepulchre, Rodolphe ULg

in Proceedings of the 43rd IEEE Conference on Decision and Control (2004, December)

This paper presents analysis and application of steering control laws for a network of self-propelled, planar particles. We explore together the two stably controlled group motions, parallel motion and ... [more ▼]

This paper presents analysis and application of steering control laws for a network of self-propelled, planar particles. We explore together the two stably controlled group motions, parallel motion and circular motion, for modeling and design purposes. We show that a previously considered control law simultaneously stabilizes both parallel and circular group motion, leading to bistability and hysteresis. We also present behavior primitives that enable piecewise-linear network trajectory tracking. [less ▲]

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See detailTrunk flexors and extensors muscular performances in healthy subjects and low back pain patients
Demoulin, Christophe ULg; Sac, Delphine; Serre, Laurent

in Abstract book of 2nd International Symposium of the Belgian Back Society (BBS) (2004, December)

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See detailClues for Differential Diagnosis of atypical myopathy
Votion, Dominique ULg; Amory, Hélène ULg; Sandersen, Charlotte ULg et al

in Proceeding of the Maastricht International Congress on Equine Medicine (MICEM) (2004, December)

Atypical myopathy (AM), also called “atypical myoglobinuria”, is a frequently and rapidly fatal myopathy of unknown origin occurring sporadically in grazing horses. As opposed to the exertional ... [more ▼]

Atypical myopathy (AM), also called “atypical myoglobinuria”, is a frequently and rapidly fatal myopathy of unknown origin occurring sporadically in grazing horses. As opposed to the exertional rhabdomyolysis syndrome (ERS), clinical signs of AM are not induced by exercise. The condition has been reported in several European countries including Belgium, France, Germany and Great Britain. Clinical signs of AM are characterised by muscular weakness, stiffness, recumbency, sweating and when urine is observed, myoglobinuria. These signs are characteristic but not pathognomonic of the disease; the differential diagnosis of sudden weakness, severe myopathy and/or unexpected death includes several neurogenic and myopathic disorders. The main pathologies that share clinical similarities with AM include the acute form of grass sickness (GS), acute piroplasmosis, botulism, ERS, the hyperkalemic periodic paresis (HPP), nutritional myopathy (NM; i.e. vitamin E and/or selenium deficiency), plants or drugs (i.e. ionophores intoxication) intoxication, tetanus and postanaesthesia myopathy. This report aims at reviewing key facts in history, clinical signs, clinical examination and laboratory findings that contribute towards the diagnosis of AM and/or invalidate the diagnosis of other pathologies. [less ▲]

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See detailWavelets Characterization of coarsing during unstable MBE growth
Moktadir, Z; Kraft, Michael ULg

in Proceedings of "Low Dimensional Semiconductor Devices Conference, Cancun, décembre 2004" (2004, December)

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See detailIntérêts et limites des machines de musculation rachidienne pour reconditionner le lombalgique chronique
Vanderthommen, Marc ULg; Demoulin, Christophe ULg; Crielaard, Jean-Michel ULg

in Abstract book of 2nd International Symposium of the Belgian Back Society (BBS) (2004, December)

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See detailMutation douce de l'enseignant en concepteur-tuteur dans des activités d'apprentissage totalement à distance. Communication présentée au Colloque TICE Méditérannée, Nice
Vandeput, Etienne ULg; Denis, Brigitte ULg

in Actes du colloque TICE Méditérannée (en ligne) (2004, November 26)

Experts in education and communication technology cannot speak about distance learning without calling up the new roles it springs up and the new relationships it generates. Its detractors claim that ... [more ▼]

Experts in education and communication technology cannot speak about distance learning without calling up the new roles it springs up and the new relationships it generates. Its detractors claim that, under these new conditions, this kind of learning requires significant and expansive means unlike a more classical one. Instead of giving up in front of such disheartening elements, the authors have been trying to measure how far a simple distance learning system (i.e. with little human, hardware and software means) can be implemented. In that way, they have been creating a learning environment basically based on a mixture of individual and collaborative works. Owing to both this mixture and the organization structure, the students can reach the fixed learning goals. Through these processes, they try to isolate practices, learners or teaching staff should be inspired by. They should, in that way, evolve slightly from a classical context to the design of learning scripts including efficient tutoring in a distance context. The course described in this paper is called “Analysis of distance learning environments”. The public consists of adults having enrolled for a DES in Education and Training Technology. To conduct this experiment, the authors have been setting themselves some rules and constraints in order to derive a general process that might be applied to various situations. These rules and constraints are very close to the usual learner’s working constraints. Recommendations focus on practices including careful preparation, coordination techniques betweenteachers and learner’s initiation into reflexivity. [less ▲]

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See detailEtude EMG du multifidus lombaire dans les radiculopathies lombo-sacrées par conflit disco-radiculaire.
TOMASELLA, Marco ULg; WANG, François-Charles ULg; CRIELAARD, Jean-Michel ULg

in Abstract Book du Symposium de Médecine Physique - EMG - Réadaptation du 20 novembre 2004. (2004, November 20)

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See detailComet C/2001 Q4 (NEAT) at its closest approach to the Earth
Tozzi, G. P.; Boehnhardt, H.; Del Bo, M. et al

in American Astronomical Society, DPS meeting #36 (2004, November 01)

Comet C/2001 Q4 (NEAT) was observed at ESO (La Silla) for three consecutive nights at the beginning of May, 2004 at its closest approach to Earth. The observations consisted of quasi-simultaneous multi ... [more ▼]

Comet C/2001 Q4 (NEAT) was observed at ESO (La Silla) for three consecutive nights at the beginning of May, 2004 at its closest approach to Earth. The observations consisted of quasi-simultaneous multi-wavelength exposures in the visible, near-IR and thermal-IR in order to study different properties of the solid component that are responsible for the scattering and emission of radiation in different spectral ranges. The comet was observed with the 3.6m telescope, equipped with TIMMI2 for the thermal-IR region, the NTT, equipped with EMMI and SOFI for the visible and near-IR regions. Narrow band images and long slit spectra were recorded for each spectral region. In the near-IR range, polarimetric observations were also performed during the last night. The aim of the observations was the characterization of the solid component at small scalelength to search for possible short lifetime organic components, as those found in the comet C/2000 WM1 (Tozzi et al., 2004, A&A, 424, 235), dust fragmentation etc.. Here we report preliminary results of the analysis of these observations. [less ▲]

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See detailFacteurs influençant la performance de terrain en volley-ball
Forthomme, Bénédicte ULg; Croisier, Jean-Louis ULg; Ciccarone, Guido et al

in Actes du XIVe Congrès National Scientifique de la Société Française de Médecine du Sport (2004, November)

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See detailInfluence of a short time specific strength training on iso-inertial performances
Jidovtseff, Boris ULg; Croisier, Jean-Louis ULg; Scimar, N. et al

in Abstract Book of the 4th International Conference on Strength Training (Serres, Greece) (2004, November)

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See detailThe Articulation of “I”, “We” and the “Person”. Elements for an Anthropological Approach within Western and Islamic Contexts
Nachi, Mohamed ULg

in Dupret, Baudouin (Ed.) Standing Trial. Law and the Person in the Modern Middle East (2004, November)

Comment les éléments constitutifs de l'identité personnelle orientent-ils les jugements des individus, leur sens moral et leur perception du juste.

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See detailIsocinétisme et prévention lésionnelle musculaire chez le footballeur professionnel
Croisier, Jean-Louis ULg; Ganteaume, S.; Ferret, J. M.

in Actes du XIVe Congrès National Scientifique de la Société Française de Médecine du Sport (2004, November)

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See detailReal-Time PCR detection of group B streptococci from pregnant women's vaginal specimens at time of delivery: clinical evaluation
MELIN, Pierrette ULg; Rodriguez Cuns, Grisel; Lorquet, Sophie et al

in American Society of Microbiology (Ed.) Program and Abstracts of the 44th Intersciences Conference on Antimicrobial Agents and Chemotherapy (2004, November)

Guidelines for prevention recommend intrapartum antimicrobial prohylaxis (IAP) for pregnant women with a positive prenatal culture-based screening for GBS. To improve this strategy, a rapid screening ... [more ▼]

Guidelines for prevention recommend intrapartum antimicrobial prohylaxis (IAP) for pregnant women with a positive prenatal culture-based screening for GBS. To improve this strategy, a rapid screening performed at the onset of labor with the IDI-Strep BTM test (IDI), a real time PCR detection (Infectio Diagnostic), may be used. Objective: To evaluate the performance of the IDI to detect GBS from vaginal specimens collected at time of delivery. Methods: Intrapartum vaginal specimens from 923 pregnant women were tested to determine the status of GBS colonization, by CDC’s recommended culture method (including selective LIM broth) with a Granada agar (GR) added as well as by the IDI and the immunologic StrepB OIATM test (OIA), BioStar. The performance of the different methods was compared. Results: GBS were recovered from 16.8% and 23.6% specimens respectively on primary culture plates and overall. The colonization rate for GBS was 18.6 % by IDI and 15.7 % by OIA testing. The sensitivity of IDI for identifying vaginal colonization status at delivery was 92 % or 77.1 % when compared to GR primary cultures or to overall culture results, and for the OIA, it was respectively 65.1 or 52.1 %. The specificity was 99.1 % for IDI and 95.5 % for OIA. The turnaround time for obtaining results was less than one hour for both IDI and OIA. Conclusions: 1) Strep B-IDI test, performed on intrapartum vaginal specimens, yields relevant results rapidly enough to be used as an efficient diagnostic tool for the identification of GBS colonized women, in order to offer IAP really targeted to GBS carriers. 2) By comparison to the prenatal screening-based strategy, the high sensitivity and specificity of IDI would allow a reduction of useless IAP and of missed opportunities. 3) IDI testing might be implemented “in routine” in some hospitals for further clinical and practical evaluation. [less ▲]

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See detailComparison of plyometric training combined with electrical stimulation versus plyometric training alone on vertical jump and sprint performance
Lehance, Cédric ULg; Vanderthommen, Marc ULg; Croisier, Jean-Louis ULg et al

in Abstract Book of the 4th International Conference on Strength Training (Serres, Greece) (2004, November)

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See detailHow many women can benefit from a full intrapartum antibiotic prphylaxis for prevention of perinatal group B streptococcal disease?
MELIN, Pierrette ULg; Lorquet, Sophie; Rodriguez Cuns, Grisel et al

in American Society of Microbiology (Ed.) Program and Abstracts of the 44th Intersciences Conference on Antimicrobial Agents and Chemotherapy (2004, November)

Background: In Belgium as in many Western countries, GBS are still the leading cause of severe perinatal infections. Current guidelines for prevention recommend intrapartum antimicrobial prohylaxis (IAP ... [more ▼]

Background: In Belgium as in many Western countries, GBS are still the leading cause of severe perinatal infections. Current guidelines for prevention recommend intrapartum antimicrobial prohylaxis (IAP) administered promptly before delivery to pregnant women colonized with GBS. The risk of vertical GBS transmission to the newborn decreases as the duration of prophylaxis increases. The considered threshold for prophylaxis adequacy is the first dose administered at least 4 hours before delivery. Objective: To evaluate the proportion of pregnant women who could benefit from an adequate IAP for the prevention of GBS perinatal infections. Methods: Between June and October 2003, we recorded in two hospitals the elapse time between admission for labor and delivery. We assumed 5 hours represent a useful threshold to allow admission, revision of chart and administration of adequate IAP. The status of vaginal colonization with GBS was determined by CDC’s recommended culture method with Granada agar added. Results: Among 532 women, 27.3 % delivered within 5 hours after admission for labor. The colonization rate for GBS was 25.6 %. The distribution of elapse time between admission and delivery for GBS colonized pregnant women was not significantly different from non colonized women (p <= 1). Conclusions: 1) With the current prevention strategy, 27.3 % of these pregnant women would not have benefit from adequate prophylaxis 2) These results highlight the importance of an efficient organization to warranty prompt administration of IAP as soon as possible when mandatory. 3) If a rapid intrapartum screening test is used, no delay can be afforded “from ward to bench to bed”. [less ▲]

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See detailInterférométrie holographique sur base de cristaux photoréfractifs dynamiques et lasers à double impulsion : le projet européen PHIFE
Georges, Marc ULg; Thizy, Cédric ULg; Lemaire, Philippe et al

in Smigielski, P. (Ed.) Actes du Cinquième colloque francophone Méthodes et Techniques Optiques pour l'Industrie (2004, November)

Les cristaux photoréfractifs sont des supports holographiques dynamiques (auto-enregistrables, effaçables et indéfiniment réutilisables) qui permettent l'acquisition rapide d'hologrammes utilisables en ... [more ▼]

Les cristaux photoréfractifs sont des supports holographiques dynamiques (auto-enregistrables, effaçables et indéfiniment réutilisables) qui permettent l'acquisition rapide d'hologrammes utilisables en interférométrie holographique. De plus, certaines de leurs propriétés cristallines permettent l'obtention d'interférogrammes de qualité incomparable. Nous avons déjà présenté à maintes reprises les développements et applications d'instruments de métrologie basés sur ces cristaux avec des lasers continus. Des expériences préliminaires sur base de lasers à simple impulsion avaient aussi été montrées. Nous présentons ici la suite de ces expériences et qui ont lieu dans le cadre du projet européen PHIFE "Pulsed Holographic Interferometer for the analysis of Fast Events". PHIFE a pour objectif le développement d'un instrument à champ complet fonctionnant avec un laser YAG Q-switch à double impulsion. [less ▲]

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See detailEffects of plyometric training combined with electrical stimulations versus plyometric training alone on functional performance
Bury, Thierry ULg

in Abstract book of 4th International Conference of Strength Training (2004, November)

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See detailQualification de grands réflecteurs en environnement spatial
Thizy, Cédric ULg; Stockman, Yvan ULg; Doyle, Dominic et al

in Smigielski, P. (Ed.) Actes du Cinquième colloque francophone Méthodes et Techniques Optiques pour l'Industrie (2004, November)

Les nouvelles générations de télescopes spatiaux dans le domaine infrarouge nécessitent des réflecteurs de grandes dimensions et de haute qualité. Ceux-ci, pour des raisons de poids, sont basés sur les ... [more ▼]

Les nouvelles générations de télescopes spatiaux dans le domaine infrarouge nécessitent des réflecteurs de grandes dimensions et de haute qualité. Ceux-ci, pour des raisons de poids, sont basés sur les technologies des matériaux composites dont les comportements aux basses températures sont mal connus. Une méthode par interférométrie holographique de vérification et de validation en environnement spatial de ce type de réflecteurs est présentée. Elle est basée sur l'utilisation d'une caméra holographique dynamique observant un dépoli sur lequel est projeté le faisceau objet venant de la surface réfléchissante. Outre une augmentation de la dynamique de mesure, cette méthode offre l’avantage principal, par rapport aux techniques d’interférométrie optique, de ne pas nécessiter de système optique d’adaptation du front d’onde au réflecteur à mesurer et donc un gain de flexibilité majeur pour des formes exotiques de réflecteurs (types asphériques). Le système de mesure a été calibré avec un interféromètre ponctuel à effet Doppler. L'influence des différentes sources d’erreur du système sur la mesure a été évaluée. Cette évaluation a porté principalement sur des aspects vibratoires et thermiques. Ces réflecteurs devant être testés sous vide et à basses températures, le système de mesure a été rendu compatible à ces conditions. Des éléments de la caméra holographique (objectifs, CCD, cristal, fibre optique) ont été adaptés et testés sous vide. La certification métrologique de l’ensemble du système sera réalisée par la mesure d'une antenne parabolique, de 1.1 m de diamètre de comportement connu et placée dans un environnement spatial simulé. Le test consistera à mesurer les déplacements et déformations de l'antenne entre un état initial à la température ambiante, et un état final à une température d'environ 130K. [less ▲]

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See detailA 2-step methodology for the generation of accurate FE models of nonlinear systems,
Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

in ASME Internaional Mechanical Engineering Congress, Anaheim, 2004 (2004, November)

Model updating and validation is currently a central issue in the fields of computational structural mechanics and dynamics. The vast majority of applications however concerns linear structures. On the ... [more ▼]

Model updating and validation is currently a central issue in the fields of computational structural mechanics and dynamics. The vast majority of applications however concerns linear structures. On the other hand, updating nonlinear models is something the structural dynamicist prefers to avoid mainly because tools such as modal analysis are no longer available. The objective of the present study is to propose a two-step methodology for dealing with nonlinear systems. Its most appealing feature is that it decouples the estimation of the linear and nonlinear parameters. A numerical application consisting of an aeroplane-like structure is used to assess the efficiency of the procedure. [less ▲]

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See detailA Machine Learning Approach to Improve Congestion Control over Wireless Computer Networks
Geurts, Pierre ULg; El Khayat, Ibtissam; Leduc, Guy ULg

(2004, November)

In this paper, we present the application of machine learning techniques to the improvement of the congestion control of TCP in wired/wireless networks. TCP is suboptimal in hybrid wired/wireless networks ... [more ▼]

In this paper, we present the application of machine learning techniques to the improvement of the congestion control of TCP in wired/wireless networks. TCP is suboptimal in hybrid wired/wireless networks because it reacts in the same way to losses due to congestion and losses due to link errors. We thus propose to use machine learning techniques to build automatically a loss classifier from a database obtained by simulations of random network topologies. Several machine learning algorithms are compared for this task and the best method for this application turns out to be decision tree boosting. It outperforms ad hoc classifiers proposed in the networking literature. [less ▲]

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See detailLa nación en los tiempos de la globalización: algunas tensiones en el discurso zapatista
Vanden Berghe, Kristine ULg

in Maihold, Günther (Ed.) Las modernidades de México. Espacios, procesos, trayectorias (2004, November)

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See detailLe tranchant des modernes (suite)
Delville, Michel ULg

in L'oeuvre en morceaux: Esthétiques de la mosaïque (2004, October 28)

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See detailPrevention of hamstring injuries in football players
Croisier, Jean-Louis ULg

in Congress book of Brucosport – 23rd Congress of Sports Medicine of the AZ Sint-Jan AV (2004, October 15)

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See detailCan hyperspectral techniques improve estimates of carbon stocks in agricultural soils ?
Stevens, A.; van Wesemael, B.; Touré, Souleymane et al

in Proceedings of the Airborne imaging spectroscopy workshop : Belspo, Bruges 8 octobre 2004 (2004, October 08)

Soil organic carbon (SOC) represents one of the major pools in the global carbon cycle. However, fluxes of CO2 from soils into the atmosphere by respiration or inversely sequestration of CO2 through ... [more ▼]

Soil organic carbon (SOC) represents one of the major pools in the global carbon cycle. However, fluxes of CO2 from soils into the atmosphere by respiration or inversely sequestration of CO2 through photosynthesis and subsequent immobilisation in the form of humus are difficult to quantify. In principle changes in SOC stock over time reflect CO2 fluxes. The detection of these stock changes, however, require intensive sampling mainly due to the large spatial variability of SOC both within individual fields and larger units with similar soils and land use. The aim of this paper is to evaluate the potential of airborne-hyperspectral techniques using a CASI sensor and hand held Near Infrared Spectroscopy (NIRS) with an ASD spectrometer to conduct SOC inventories of individual parcels. During a field campaign in the Belgian Ardennes during Octobre 2003, more than 120 sites on a regular grid within 13 freshly ploughed fields were selected. At these sites, field spectra of the bare soil have been measured and samples from the topsoil were taken. SOC content (Walkley and Black), soil moisture and bulk density of these samples have been determined. As a first step, the soil reflectance has been transformed (log (1/R), Savitsky-Golay smoothing and derivative, gap derivative, moving average) in order to filter the spectral responses and to eliminate noise. Then, we used both stepwise and partial least square (PLS) regression analysis to relate these spectra to measured SOC contents. Regression models performed much better when the data were divided in two sub-groups representing different moisture conditions of the soil surface. These statistical model calibrations were validated on an independent data set. Standard Error of Prediction (SEP) ranged from 0.19 to 0.24 % carbon for the field spectra determined using the ASD depending on soil moisture of the surface layer. This is a little bit more than the reproducibility error inherent to the Walkley and Black analysis. Airborne CASI techniques performed less well mainly due to the narrow spectral range. Tests on airborne CASI+SASI hyperspectral data from a previous field campaign [1] showed better results. Overall, low bias allowed the use of spectral techniques to estimate population means with a high confidence level. The spectral techniques have a strong potential in determining changes in carbon tock change studies. The large within field variability of SOC content precludes the assessment, using conventional soil sampling, of SOC changes as a result of management (1 t C ha-1 yr-1) over a reasonable time period (5 years). Depending on the variance of the SOC content measured in the field ( 2 = 11-166 t C ha-1), we need 16-210 samples to detect a change. Since this number of samples is rarely available for individual fields, conventional sampling methods can only be used for larger spatial units containing many fields. In contrast, the airborne-hyperspectral technique and portable NIRS are able to supply these large amounts of data, and can thus improve the accuracy of SOC stock assessments of individual fields. This in turn will result in a smaller detection limit of SOC stock changes. [less ▲]

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See detailAirborne hyperspectral measurements and superficial soil organic matter
Touré, Souleymane; Tychon, Bernard ULg

in Proceedings of the Airborne Imaging Spectroscopy Workshop (2004, October 08)

Data acquired from field campaign and hyperspectral airborne sensors were processed to determine the surface soil organic matter of an agricultural area located in Southern Belgium. The method adopted was ... [more ▼]

Data acquired from field campaign and hyperspectral airborne sensors were processed to determine the surface soil organic matter of an agricultural area located in Southern Belgium. The method adopted was based on a forward stepwise multiple linear regression analysis linking soil organic matter and hyperspectral data from the CASI-2 (Compact Spectrographic Imager-2) airborne sensor working in the visible and near infrared domain. The results were validated successfully from an independent set of sampling points. However, disturbing factors effects are shown on the relationship between soil organic matter and spectral reflectance. It is concluded that the hyperspectral remote sensing approach is promising for soil organic matter prediction but it will require more study to better take account on the disturbing factors affecting the relationship. [less ▲]

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See detailTheoretical Instability Strips and Non-Adiabatic Photometric Observables for d Scut and g DOR Stars
Dupret, Marc-Antoine ULg; Grigahcène, A.; Garrido, R. et al

in SOHO 14 Helio- and Asteroseismology: Towards a Golden Future (2004, October 01)

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See detailSolar Model with CNO Revised Abundances
Montalban Iglesias, Josefa ULg; Miglio, Andrea ULg; Noels-Grötsch, Arlette ULg et al

in Danesy, D. (Ed.) Proceedings of the SOHO 14 / GONG 2004 Workshop (ESA SP-559). "Helio- and Asteroseismology: Towards a Golden Future" (2004, October 01)

Recent three-dimensional, NLTE analyses of the solar spectrum have shown a significant reduction in the C, N, O and Ne abundances leading to a Z/X ratio of the order of 0.0177. We have computed solar ... [more ▼]

Recent three-dimensional, NLTE analyses of the solar spectrum have shown a significant reduction in the C, N, O and Ne abundances leading to a Z/X ratio of the order of 0.0177. We have computed solar models with this new mixture in the OPAL opacity tables. The present He abundance we find seems rather consistent with the helioseismic value. However, the convective envelope is too shallow, and diffusion, even if it reduces the discrepancy, is not able to give the current value. We present some numerical experiments consisting in changing the diffusion velocities and/or the value of opacity at the base of the convective envelope. [less ▲]

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See detailConvection-Oscillations Interaction in F-G Type Main Sequence Stars
Dupret, Marc-Antoine ULg; Grigahcène, A.; Garrido, R. et al

in SOHO 14 Helio- and Asteroseismology: Towards a Golden Future (2004, October 01)

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See detailDarwin-GENIE: a nulling instrument at the VLTI
Gondoin, Philippe A; Absil, Olivier ULg; den Hartog, Roland H et al

in Traub, Wesley (Ed.) New Frontiers in Stellar Interferometry (2004, October 01)

Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives are to detect Earth-like planets around nearby stars and to characterise ... [more ▼]

Darwin is one of the most challenging space projects ever considered by the European Space Agency (ESA). Its principal objectives are to detect Earth-like planets around nearby stars and to characterise their atmospheres. Darwin is conceived as a space "nulling interferometer" which makes use of on-axis destructive interferences to extinguish the stellar light while keeping the off-axis signal of the orbiting planet. Within the frame of the Darwin program, the European Space Agency (ESA) and the European Southern Observatory (ESO) intend to build a ground-based technology demonstrator called GENIE (Ground based European Nulling Interferometry Experiment). Such a ground-based demonstrator built around the Very Large Telescope Interferometer (VLTI) in Paranal will test some of the key technologies required for the Darwin Infrared Space Interferometer. It will demonstrate that nulling interferometry can be achieved in a broad mid-IR band as a precursor to the next phase of the Darwin program. The instrument will operate in the L' band around 3.8 mum, where the thermal emission from the telescopes and the atmosphere is reduced. GENIE will be able to operate in two different configurations, i.e. either as a single Bracewell nulling interferometer or as a double-Bracewell nulling interferometer with an internal modulation scheme. [less ▲]

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See detailThree telescope nuller based on multibeam injection into single-mode waveguide
Karlsson, Anders L; Wallner, Oswald; Perdigues Armengol, Josep M et al

in Traub, Wesley (Ed.) New Frontiers in Stellar Interferometry (2004, October 01)

Nulling interferometry of exo-solar planets requires as a minimum two telescopes, of which one is phase shifted by 180 degrees, such that the on-axis stellar object is cancelled, while the light from the ... [more ▼]

Nulling interferometry of exo-solar planets requires as a minimum two telescopes, of which one is phase shifted by 180 degrees, such that the on-axis stellar object is cancelled, while the light from the off-axis planet interferes constructively. Improvement of the nulling performance and the introduction of chopping leads to space interferometers of four or more telescopes and a separate spacecraft dedicated to beam recombination, as currently baselined for Darwin and TPF. It has recently been demonstrated that the stellar leaks mainly affects the integration times for near-by target stars [o,c]. Considering that there are only a few near-by targets and that the integrations times for each of these is short compared to that of distant stars, it appears advantageous to simplify the interferometer, by accepting higher levels of stellar leaks for near-by targets. A simple, chopping nulling interferometer can be obtained by adding one equal size telescope to the basic two telescope nulling interferometer. Modulation is obtained by applying time-varying phase-shifts to the beams before recombination, i.e. inherent modulation [d]. The recombination of 3 multi-axial beams is achieved by coupling into a single mode waveguide, leading to high modulation and coupling efficiencies, and a single focal plane [i]. Linear and circular telescope configurations are proposed and investigated, including a discussion on the need of a separate spacecraft for beam recombination. The associated transmission and modulation maps and efficiencies are calculated and discussed. [less ▲]

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See detailThermal background fluctuations at 10 micron measured with VLTI/MIDI
Absil, Olivier ULg; Bakker, Eric; Schoeller, Markus et al

in Traub, Wesley; Monnier, John; Schöller, Markus (Eds.) New Frontiers in Stellar Interferometry (2004, October 01)

We present an experiment to measure the thermal background level and its fluctuations with the European Southern Observatory (ESO) Very Large Telescope Interferometer (VLTI). The Mid Infrared Instrument ... [more ▼]

We present an experiment to measure the thermal background level and its fluctuations with the European Southern Observatory (ESO) Very Large Telescope Interferometer (VLTI). The Mid Infrared Instrument (MIDI) operating between 8 and 12 micron was used in both dispersed and non-dispersed modes. By using an interferometric instrument, in non-interferometric mode, we probe the same optical path as can be expected for other infrared interferometric instruments, e.g. GENIE and MIDI itself. Most of the infrared thermal background detected with MIDI originates from the VLTI infrastructure. This can be attributed to the absence of a pupil re-imaging mirror. Only for a small region around the optical axis of the system the signal from the VLTI infrastructure can be considered small and the atmospheric background fluctuations can be characterized. The fluctuations of the thermal emission are described in terms of their power spectral densities (PSD). We have identified two regions in the PSD. For the low frequency range (0-10 Hz) the fluctuations are dominated by the Earth atmosphere. The slope of the log-log PSD is close to -1. For the high frequency (larger than 10 Hz) range the fluctuations are due to photon noise and the PSD flattens off. Many narrow peaks are present in the PSD. Peaks at 1 and 50 Hz occur in almost all data sets and are identified as the effects of the MIDI closed cycle cooler and the power lines respectively. Other peaks at 10 and 30 Hz, as well as peaks above 50 Hz, are assumed to be VLTI or MIDI-specific frequencies. [less ▲]

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See detailInfluence of atmospheric turbulence on the performance and design of GENIE
Absil, Olivier ULg; den Hartog, Roland; Gondoin, Philippe et al

in Traub, Wesley; Monnier, John; Schöller, Markus (Eds.) New Frontiers in Stellar Interferometry (2004, October 01)

Two competitive design studies for the Ground-based European Nulling Interferometer Experiment (GENIE) have been initiated by the European Space Agency and the European Southern Observatory in November ... [more ▼]

Two competitive design studies for the Ground-based European Nulling Interferometer Experiment (GENIE) have been initiated by the European Space Agency and the European Southern Observatory in November 2003. The GENIE instrument will most probably consist of a two-telescope Bracewell interferometer, using the 8-m Unit Telescopes and/or the 1.8-m Auxiliary Telescopes of the VLTI, and working in the infrared L' band (3.5 - 4.1 microns). A critical issue affecting the overall performance of the instrument is its capability to compensate for the phase and intensity fluctuations produced by the atmospheric turbulence. In this paper, we present the basic principles of phase and intensity control by means of real-time servo loops in the context of GENIE. We then propose a preliminary design for these servo loops and estimate their performance using GENIEsim, the science simulation software for the GENIE instrument. [less ▲]

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See detailThe simulated detection of low-mass companions with GENIE
den Hartog, Roland H; Absil, Olivier ULg; Gondoin, Philippe A et al

in Traub, Wesley; Monnier, John; Schöller, Markus (Eds.) New Frontiers in Stellar Interferometry (2004, October 01)

The prime objective of GENIE (Ground-based European Nulling Interferometry Experiment) is to obtain experience with the design, construction and operation of an IR nulling interferometer, as a preparation ... [more ▼]

The prime objective of GENIE (Ground-based European Nulling Interferometry Experiment) is to obtain experience with the design, construction and operation of an IR nulling interferometer, as a preparation for the DARWIN / TPF mission. In this context, the detection of a planet orbiting another star would provide an excellent demonstration of nulling interferometry. Doing this through the atmosphere, however, is a formidable task. In this paper we assess the prospects of detecting with nulling interferometry on ESO's VLTI, low-mass companions in orbit around their parent stars. With the GENIE science simulator (GENIEsim) we can model realistic detection scenarios for the GENIE instrument operating in the VLTI environment, and derive detailed requirements on control-loop performance, IR background subtraction and the accuracy of the photometry calibration. We analyse the technical feasibility of several scenarios for the detection of low-mass companions in the L'-band. [less ▲]

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See detailHolographic interferometry with photorefractive crystals. Early experiments and results of the ongoing european project PHIFE
Georges, Marc ULg; Thizy, Cédric ULg; Lemaire, Philippe et al

in Dantec Ettemeyer 11th International User Meeting (2004, October)

Photorefractive crystals offer many advantages over other classical holographic recording media. They allow fast in-situ processable holographic recording as well as indefinite reusability. Moreover high ... [more ▼]

Photorefractive crystals offer many advantages over other classical holographic recording media. They allow fast in-situ processable holographic recording as well as indefinite reusability. Moreover high signal-to-noise ratio can be reached as well as high resolutions. We present several types of holographic instruments using such materials. Here we will emphasize their applications in vibration measurements. A first one is based on the classical stroboscopic technique, a second one uses a pulsed laser. We describe also the recent results obtained in the framework of the european project PHIFE (Pulsed Holographic Interferomete for the analysis of Fast Events), aiming at developing a full field measurement system of vibrations modes at high repetition rate. [less ▲]

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See detailEffect of inhaled fluticasone on airway reactivity and 8-Iso-PGF2 in bronchoalveolar lavage fluid of cats
Kirschvink, N.; Leemans, J.; Delvaux, François ULg et al

in 5th China - France Pharmacological Joint Symposium - Beijing - France - Octobre 2004 (2004, October)

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See detailComparaison de différentes méthodes de détermination des teneurs en éléments majeurs et traces dans les sols.
Colinet, Gilles ULg; Baize, Denis; Delcarte, Emile et al

in Actes des 8emes JNES (2004, October)

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See detailA new training simulator for improved voltage control of the Hydro-Québec system
Van Cutsem, Thierry ULg; Hassé, Gaëtan; Moors, Cédric et al

in Proc. IEEE Power System Conference and Exposition (PSCE) (2004, October)

This paper reports on the development of a training simulator focusing on voltage control and stability. It has been derived from a quasi steady-state simulation software already used and validated in ... [more ▼]

This paper reports on the development of a training simulator focusing on voltage control and stability. It has been derived from a quasi steady-state simulation software already used and validated in planning and operational planning studies. The computational engine has been provided with a user interface built on the client-server architecture, allowing the simulator to run on a network of PCs in a very flexible way. New displays can be set up easily and quickly. This tool is presently used by Hydro-Québec to improve the operator’s ability to control transmission voltages. Other features, uses and benefits are reported. [less ▲]

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See detailEffect of inhaled fluticasone on airway reactivity and inflammation in cats.
Kirschvink, N.; Leemans, J.; Delvaux, F. et al

in 22nd Veterinary and Comparative Respiratory Society Symposium - Montreal- Canada - Octobre 2004 (2004, October)

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See detailDevelopment of Advanced Driver Assistance Systems by means of the traffic flow simulation tool PELOPS with HiL-functionalities
Christen, Fréderic ULg; Benmimoun, A.; Breuer, K. et al

in Berechnung und Simulation im Fahrzeugbau (2004, September 29)

During the last years a rapid increase of traffic volume in association with limited road space could be observed. This led to a raising load of the driver while achieving his driving tasks. Therefore so ... [more ▼]

During the last years a rapid increase of traffic volume in association with limited road space could be observed. This led to a raising load of the driver while achieving his driving tasks. Therefore so called Advanced Driver Assistance Systems (ADAS) are under development in recent years with an upward tendency. Such systems will relieve the driver and improve safety on the road in the future. A rising number of computed-aided-simulation becomes important for the development and evaluation of such systems. Developing ADAS makes a specific demand on the simulation environment. ADAS interact strongly with their traffic environment. Therefore the simulation has to cover both, a detailed model of the ego vehicle and an adequate representation of the traffic environment. The traffic flow simulation program PELOPS meets these requirements. The newly implemented extension of PELOPS with techniques of Software- and Hardware-in-the-Loop-simulation (SiL- and HiL-simulation) allows system developers a fast functional check and an assessment of new ADAS. External software can be linked to PELOPS via Ethernet-based network communication, which has already been realised for the widely used development tool MATLAB/Simulink. Besides the Ethernet interface PELOPS-HiL (PHIL) gives the developer two other possibilities for providing a HIL-environment: a serial interface which can be used for a connection to a dSpace development platform and a CAN data bus interface. The following article describes by means of chosen examples how flexible the PHIL-simulation can be adapted to a development task and which results can be obtained. [less ▲]

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See detailOptimisation of poly(2-(dimethylamino)ethyl methacrylate)-co-poly(ethyleneglycol) /DNA complexes designed for cell transfection
Grandfils, Christian ULg; Emonds-Alt, J

in Proceeding BRG XIIth International Workshop on Bioencapsulation Meeting (2004, September 24)

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See detailUtilization of a probiotic-hemicellulases combination to prevent effects of Salmonella contamination of broilers
Dubois Dauphin, Robin ULg; Vandeplas, Sabrina ULg; Welling, Gjalt W. et al

in Proceedings of the Ninth Conference on Food Microbiology (2004, September 16)

The aim of this study was to determine the effectiveness of a combination probiotic - hemicellulases by its relative incidence on gastrointestinal (GI) tract microbiota, correlated to the animal ... [more ▼]

The aim of this study was to determine the effectiveness of a combination probiotic - hemicellulases by its relative incidence on gastrointestinal (GI) tract microbiota, correlated to the animal performances during the growing period of broilers infected or not with Salmonella typhimurium [less ▲]

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See detailLa qualité des froments d'hiver en 2004?
Sinnaeve, Geoges; Lenartz, J.; Vancutsem, Françoise ULg et al

in Livre Blanc: Céréales - Gembloux - Informations avant les semis (2004, September 09)

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See detailLe froment d'hiver
Couvreur, Luc; Vancutsem, Françoise ULg; Bodson, Bernard ULg et al

in Livre Blanc: Céréales - Gembloux - Informations avant les semis (2004, September 09)

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See detailEscourgeon et Orge d'hiver fourragers
Monfort, Bruno; Herman, Jean-Luc; Bodson, Bernard ULg et al

in Livre Blanc: Céréales - Gembloux - Informations avant les semis (2004, September 09)

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See detailThe Polarization Evolution of the Optical Afterglow of GRB 030329
Greiner, J.; Klose, S.; Reinsch, K. et al

in GAMMA-RAY BURSTS: 30 YEARS OF DISCOVERY (2004, September 01)

We report 31 polarimetric observations of the afterglow of GRB 030329 with high signal-to-noise and high sampling frequency. The data imply that the afterglow magnetic field has small coherence length and ... [more ▼]

We report 31 polarimetric observations of the afterglow of GRB 030329 with high signal-to-noise and high sampling frequency. The data imply that the afterglow magnetic field has small coherence length and is mostly random, probably generated by turbulence. [less ▲]

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See detailOPEN-LOOP STABILIZATION OF 2D IMPACT JUGGLING
Ronsse, Renaud; Lefèvre, Philippe; Sepulchre, Rodolphe ULg

in Proceedings of 6th IFAC Symposium on Nonlinear Control Systems (2004, September)

The paper studies the properties of a sinusoidally vibrating wedge billiard as a model for 2D impact juggling. It is shown that some periodic orbits that are unstable in the elastic xed wedge become ... [more ▼]

The paper studies the properties of a sinusoidally vibrating wedge billiard as a model for 2D impact juggling. It is shown that some periodic orbits that are unstable in the elastic xed wedge become exponentially stable in the (non-)elastic vibrating wedge. These orbits are linked with some classical juggling patterns, providing an interesting benchmark for the study of the frequency-locking properties in human rhythmic tasks. [less ▲]

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See detailEchocardiography as an aid in the diagnosis of pulmonary thrombo-embolism
Van Israel, N.; Clercx, Cécile ULg; Else, R. W.

in 14th ESVIM Meeting - Barcelona - Espagne (2004, September)

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See detailSTABILIZATION THROUGH WEAK AND OCCASIONAL INTERACTIONS : A BILLIARD BENCHMARK
Gerard, Manuel; Sepulchre, Rodolphe ULg

in Proceedings of the 6th IFAC Symposium on Nonlinear Control Systems (2004, September)

The paper addresses the stabilization of periodic orbits in a wedge billiard with actuated edges. It is shown how the rich dynamical properties of the open-loop dynamics, e.g. ergodicity properties and ... [more ▼]

The paper addresses the stabilization of periodic orbits in a wedge billiard with actuated edges. It is shown how the rich dynamical properties of the open-loop dynamics, e.g. ergodicity properties and KAM curves, can be exploited to design robust stabilizing feedbacks with large basins of attraction. [less ▲]

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See detailA high-performance accelerometer with a fifth-order sigma--delta modulator
Dong, Yufeng; Kraft, Michaël ULg; Gollasch, Carsten O.

in 15th European Workshop on Micromechanics, MME 2004 (2004, September)

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See detailDetection of defects on fruits by machine vision and unsupervised segmentation
Kleynen, Olivier; Destain, Marie-France ULg

in AgEng 2004 Conference (2004, September)

Defect detection on fruits by machine vision is a complex task. Indeed, the sound tissue colour is not uniform and the defects present a wide variability in colour, shape and texture. Mostly often, images ... [more ▼]

Defect detection on fruits by machine vision is a complex task. Indeed, the sound tissue colour is not uniform and the defects present a wide variability in colour, shape and texture. Mostly often, images are acquired by conventional RGB cameras and defect segmentation is performed by algorithms based on Bayes' rules. The efficiency of these methods can be improved firstly by acquiring images with a dedicated vision system (multi-spectral imager) and secondly by implementing unsupervised segmentation methods (method derived from the 'mean shift' procedure of Camaniciu and Meer, 2002). [less ▲]

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See detailDynamique d'une population de martins pêcheurs (Alcedo atthis) en Belgique en liaison avec la gestion des cours d'eau.
Libois, Roland ULg

in Actes du 1er colloque international "gestion et préservation des ressoures en eau" (2004, September)

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See detailChemo-Mechanical Modelling of Soil or Rock Degradation
Charlier, Robert ULg; Boukpeti, N.

in 2nd Int. Symposium on Continuous and Discontinuous Modelling of Cohesive Frictional Materials. (2004, September)

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See detailFringe capacitance models for MEMS devices
Houlihan, Ruth; Kraft, Michaël ULg

in 15th European Workshop on Micromechanics, MME 2004 (2004, September)

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See detailLupin seeds as a substitute to soybean in broiler chiken feeding : incorporation level and enzyme preparation effects on performances, digestibility and meat composition.
Froidmont, Eric; Beckers, Yves ULg; Dehareng, frédéric et al

in 55th Meeting of European Association of Animal Production (2004, September)

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See detailSolid-state electronic interface for a levitated disc accelerometer
Gindila, Mircea V.; Kraft, Michaël ULg; Houlihan, Ruth et al

in Eurosensors XVIII, 18th European Conference on Solid-State Sensors (2004, September)

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See detailUtilization of a probiotic-hemicellulases combination to prevent effects of Samonella contamination of broilers.
Dubois Dauphin, Robin ULg; Vandeplas, Sabrina ULg; Welling, Gjalt et al

in Proceeding of the 9th Conference on Food Microbiology, University of Gent (Belgium), September 16-17, 2004 (2004, September)

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See detailWhole-body barometric plethysmography in healthy dogs: effect of sedation on basal respiratory variables and during histamine challenge
Talavera, J.; Kirschvink, N.; Clercx, Cécile ULg

in 14th ESVIM Meeting - Barcelona - Espagne (2004, September)

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See detailUltimate strength of aluminium stiffened panels: Sensitivity analysis
Rigo, Philippe ULg; Sarghiuta, R.; Otelea, C. et al

in PRADS’2004, 9th Int. Symposium on Practical Design of Ships and other Floating Structures, Germany, Seehafen Verslag GmbH, Hambourg, vol.1, Sept. 2004 (2004, September)

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See detailModelling groundwater flow and solute transport in karstic systems: from dreams to the reality – how can models help for groundwater vulnerability assessment ?
Dassargues, Alain ULg

in Proceedings of Trans-Karst 2004, International Transdisciplinary Conference on Development and Conservation of Karst Regions (2004, September)

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See detailSensor network design using genetic algorithm
Gerkens, Carine ULg; Heyen, Georges ULg

(2004, September)

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See detailIntegration of a two-dimensional electrostatic actuator in a new generation of atom chips
Gollasch, Carsten O.; Moktadir, Zakaria; Koukharenko, Elena et al

in Eurosensors XVIII, 18th European Conference on Solid-State Sensors (2004, September)

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See detailEffect of Welding on Ultimate Compressive Strength of Aluminium Stiffened Panels
Rigo, Philippe ULg; Richir, T.; Toderan, C. et al

in HIPER’2004, High Performances Marine Vehicules (2004, September)

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See detailDilatometric Investigations on the Decomposition of Austenite in Two Medium-Carbon Steels With and Without Cr and Mo Additions
Mertens, Anne ULg; Brown, Andrew J.; Zhao, Lie et al

in Proceedings of the MS&T'04 Conference (2004, September)

The interest of small additions of Cr (< 3 wt %) and Mo (~ 0.2 wt %) in steels for automotive and bearing applications has been recently highlighted. The microstructure of these steels is primarily based ... [more ▼]

The interest of small additions of Cr (< 3 wt %) and Mo (~ 0.2 wt %) in steels for automotive and bearing applications has been recently highlighted. The microstructure of these steels is primarily based on the bainitic phase. In order to optimize their microstructure and their mechanical properties, it is, therefore, of primary importance to gain a better understanding of the influence of Cr and Mo on austenite decomposition in varying temperature regimes with a particular attention to the transition between ferrite, bainite and martensite formation. In the present work, dilatometry, combined with detailed microstructural characterisation, is used in order to obtain a full view of transformation processes and kinetics in two medium-carbon steels with and without Cr and Mo additions. [less ▲]

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See detailValidating Blade Vibration Amplitudes from Blade Tip-Timing Data Analysis
Gallego-Garrido, Jon; Dimitriadis, Grigorios ULg

in Vibrations in Rotating Machinery (2004, September)

Blade Tip-Timing (BTT) is a method for the measurement of blade vibration in rotating bladed assemblies such as those found in turbomachinery. BTT data needs to be analysed by specially formulated methods ... [more ▼]

Blade Tip-Timing (BTT) is a method for the measurement of blade vibration in rotating bladed assemblies such as those found in turbomachinery. BTT data needs to be analysed by specially formulated methods, to yield the vibration frequencies and amplitudes. Although such methods have been shown to recover frequencies successfully, they have not been validated experimentally for amplitude recovery. In the present paper an improved experimental procedure for amplitude measurement is described. The paper presents a comparison between the experimental observation of the blade vibration amplitudes and the answers obtained from the BTT data analysis methods, providing experimental evidence of the ability of these methods to extract the correct blade vibration amplitudes from BTT data. [less ▲]

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See detailA three-dimensional electrostatic actuator with a locking mechanism for a new generation of atom chips
Gollasch, CO; Moktadir, Z; Kraft, Michael ULg et al

in Proceedings of "MME 2004 Conference, Belgique - Septembre 2004" (2004, September)

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See detailOn the solution of the aeroelastic galloping problem
Vio, Gareth Arthur; Dimitriadis, Grigorios ULg; Cooper, Jonathan Edward

in Proceedings of the 2004 International Conference on Noise and Vibration Engineering (2004, September)

A global stability analysis of the transverse galloping of a square section beam in a normal steady ow was performed. The analysis was applied to a mathematical model using experimentally measured ... [more ▼]

A global stability analysis of the transverse galloping of a square section beam in a normal steady ow was performed. The analysis was applied to a mathematical model using experimentally measured stationary aerodynamic forces. The system was modelled as an ordinary differential equation with small non-linearity in the velocity term. Three methods are used for the stability analysis: 1. a harmonic balance approach, 2. normal form theory, 3. cell mapping. The resulting stability predictions were compared with each other and with results obtained from numerical integration. It is shown that the hysteretic stability of the non-linear aeroelastic oscillator was captured by all the methods. Additionally, the methods had a varying degree of success in predicting the amplitude of limit cycle oscillations undergone by the aeroelastic oscillator. [less ▲]

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See detailPerformance increase of carbon dioxide refrigeration cycle with the addition of parallel compression economization
Bell, Ian ULg

in Proceedings of the 6th IIR Gustav Lorenzen Natural Working Fluids (2004, September)

In the future, it would be preferable to replace the halocarbon refrigerants with natural refrigerants like carbon dioxide, but there have been concerns over the use of carbon dioxide as a refrigerant due ... [more ▼]

In the future, it would be preferable to replace the halocarbon refrigerants with natural refrigerants like carbon dioxide, but there have been concerns over the use of carbon dioxide as a refrigerant due to its perceived inefficiency. It is possible to partially overcome this problem by the manipulation of the cylinders of the compressors used in the vapor compression refrigeration cycle. If some of the cylinders are used to compress vapor in a parallel compression system from an intermediary pressure, a refrigerating effect and COP greater than that of the system with all of the cylinders on suction can be achieved. An analytic model was created that allowed environmental and physical parameters to be altered. The investigations also included experimentation with the addition of superheat for the primary compression path, for which performance increases were noted for some operating conditions. The primary focus of the research was for the use of carbon dioxide in a standard air conditioning application. Accordingly, evaporation and condensation pressures were selected to correspond closely with evaporation and condensation temperatures for other refrigerants. Under the conditions used for the following research, superheating did not improve efficiency, and was not included. Physical limitations placed on the ratio of the suction cylinder swept volume to the economized cylinder swept volume suggest that building this economized compressor would be feasible. In fact, a standard reciprocating compressor could be altered such that 2 to 4 cylinders, depending on the volumetric ratio, are used for the economized path. The research demonstrates that under some conditions an economized carbon dioxide system outperforms a similar halocarbon system in terms of efficiency and capacity. In the end, this is the litmus test that proves that carbon dioxide can compete on the level with popular halocarbon refrigerants in this economized mode. [less ▲]

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See detailControl of Listeria monocytogenes in dairy farms.
Di Tanna, Sybille ULg; Belleflamme, Christel ULg; Anceau, Christine ULg et al

in Proceedings of the Ninth conference on food microbiology (2004, September)

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See detailBronchial reactivity assessed by whole body barometric plethymography is correlated with lower airway inflammation in cats
Kirschvink, N.; Leemans, J.; Delvaux, François ULg et al

in 14th ESVIM Meeting - Barcelona - Espagne (2004, September)

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See detailStability and Limit Cycle Oscillation Amplitude Prediction for Multi-DOF Aeroelastic Systems with Piecewise Linear Non-Linearities
Dimitriadis, Grigorios ULg; Vio, Gareth Arthur; Cooper, Jonathan Edward

in Proceedings of the 2004 International Conference on Noise and Vibration Engineering (2004, September)

Discontinuous non-linearities such as freeplay and bilinear stiffness are often encountered in aeroelastic systems, sometimes as a result of wear and tear. It is important to predict the effect of such ... [more ▼]

Discontinuous non-linearities such as freeplay and bilinear stiffness are often encountered in aeroelastic systems, sometimes as a result of wear and tear. It is important to predict the effect of such non-linearities on the dynamic behaviour of a system, so that adequate safety guidelines can be drafted. As a consequence, the prediction of the bifurcation behaviour of a system featuring a discontinuous nonlinearity is crucial. Additionally, the post-bifurcation behaviour of the system is also of interest since it may consist of relatively harmless Limit Cycle Oscillations (LCO) of low amplitude or of unexpected catastrophic high amplitude LCOs. In this paper the bifurcation and post-bifurcation behaviour of a simulated Multi-DOF aeroelastic system with bilinear and freeplay nonlinearities are investigated using the Harmonic Balance method and a novel method for the prediction of the bifurcation conditions and LCO amplitudes. The method is based on the fact that the nonlinearities investigated are piecewise linear. The ratios of the real parts of the system eigenvalues in the various ranges of the bilinear spring are used in order to infer LCO amplitude information. By means of a demonstration on a simulated aeroelastic system with piece-wise linear stiffness, it is shown that the proposed approach is successful in yielding the full bifurcation and post-bifurcation behaviour of the system. Comparison of the amplitude predictions obtained from the Harmonic Balance technique and the Piecewise Linearisation proposed approach show that the latter are more consistent and closer to the true amplitudes throughout the airspeed range. The bifurcation analysis is extended to the special case where the inner stiffness of the bilinear spring is equal to zero, i.e. freeplay stiffness. It is shown that the Piecewise Linear analysis fails to capture the bifurcation behaviour for this case, while the Harmonic Balance method still produces some accurate predictions. [less ▲]

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See detailDesign and simulation of a spring-less micro switch
Kiang, Kian Shen; Houlihan, Ruth; Gindila, Mircea et al

in 15th European Workshop on Micromechanics, MME 2004 (2004, September)

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See detailPractical case of HACCP methodology used for Staphylococcus aureus groth control in raw milk "fromage frais".
Broze, Olivier; Defrize, Nathalie; Sindic, Marianne ULg et al

in Proceedings of the Ninth conference on food microbiology (2004, September)

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See detailEcologie de la loutre (Lutra lutra) et conservation de ses habitats riverains
Libois, Roland ULg

in Actes du 1er colloque international "gestion et préservation des ressoures en eau" (2004, September)

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See detailA guidance assistance method for precision sugar beet sowing using machine vision.
Leemans, Vincent ULg; Destain, Marie-France ULg

in Pr. Josse De Baerdemaeker (Ed.) AgEng 2004 Conference - Engineering the future - Book of abstracts (2004, September)

This paper presents a method for seed drill guidance by using machine vision

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See detailIndices of oxidative stress in a feline model of asthma : 8-Iso-PGF2 in bronchoalveolar lavaeg and H2O2 in exhaled breath condensate
Kirschvink, N.; Fievez, Laurence ULg; Leemans, J. et al

in 14th ERS Annual Congress (2004, September)

Detailed reference viewed: 10 (1 ULg)