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See detailAn educational simulation tool for power system control and stability
Vournas, Costas; Potamianakis, Emmanuel G.; Moors, Cédric et al

in IEEE Transactions on Power Systems (2004), 19(1), 48-55

This paper presents a Simulink-based educational tool developed for the purpose of illustrating power system control and stability notions as well as introducing students to realistic, though tractable in ... [more ▼]

This paper presents a Simulink-based educational tool developed for the purpose of illustrating power system control and stability notions as well as introducing students to realistic, though tractable in size, design problems. Relevant courses are taught to last-year undergraduate as well as graduate students at the University of, Liege, Belgium, and the National Technical University of Athens, Greece.. After a brief description of the corresponding curricula, the paper describes the simulation tool and gives examples of problems and assignments given to the students. [less ▲]

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See detailDesign and test of a circular notch hinge
Merken, Patrick; Smal, Olivier; Debongnie, Jean-François ULg et al

in Proceedings of the International Precision Assembly Seminar (2004, February)

At the microscale, classical bearings such as ball bearings, sliding bearings and other pivots may be difficult to manufacture. Among all possible solutions to replace them, the notch hing seems to be ... [more ▼]

At the microscale, classical bearings such as ball bearings, sliding bearings and other pivots may be difficult to manufacture. Among all possible solutions to replace them, the notch hing seems to be very attractive through its many advantages. The major limitation is on the rotation angle. This paper presents a new simplified analytical model for the prediction of the maximum angular displacement and the angular stiffness of a notch hinge. To validate our model, an experimental set-up has been developed. [less ▲]

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See detailMise au point d'une méthode de détermination in vitro du taux de fermentation des fibres dans le gros intestin du porc
Boudry, Christelle ULg; Buldgen, André; Anciaux, Benoit et al

in 36èmes Journées de la Recherche Porcine (2004, February)

L’objectif des études synthétisées dans cette communication consiste à mettre au point une méthode in vitro, simple, fiable et respectueuse du bien-être animal, pour mesurer la fermentation des fibres ... [more ▼]

L’objectif des études synthétisées dans cette communication consiste à mettre au point une méthode in vitro, simple, fiable et respectueuse du bien-être animal, pour mesurer la fermentation des fibres dans le gros intestin du porc. Les travaux ont été réalisés en adaptant la méthode de BOISEN et FERNANDEZ à la pepsine-pancréatine pour simuler la digestion des aliments dans la première partie du tube digestif. La méthode d’incubation en seringues de MENKE et STEINGASS a ensuite été utilisée pour quantifier la production de gaz des résidus de la prédigestion. Les expériences, réalisées au moyen de porcs en croissance, ont porté sur la quantité et le mode de filtration des substrats prédigérés par la pepsine-pancréatine, l’identification d’un aliment de référence, la dilution des inoculi dans la solution tampon en seringues et la comparaison des fermentations, en utilisant comme inoculi des contenus d’intestin ou des matières fécales. Les résultats montrent que la répétabilité de la digestion in vitro par la pepsine-pancréatine est satisfaisante et que les quantités d’aliment incubées peuvent être augmentées par rapport à la méthode de référence. La filtration des résidus peut être réalisée sur creusets filtrants ou sur toile Nylon. La pulpe de betterave constitue un aliment témoin idéal. Après 24 h d’incubation, la production de gaz obtenue à partir d’inoculi fécaux dilués 20 fois dans la solution tampon est identique à celle enregistrée à partir d’inoculi intestinaux dilués 10 fois dans le même tampon. [less ▲]

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See detailPower systems stability control: Reinforcement learning framework
Ernst, Damien ULg; Glavic, Mevludin; Wehenkel, Louis ULg

in IEEE Transactions on Power Systems (2004), 19(1), 427-435

In this paper, we explore how a computational approach to learning from interactions, called reinforcement learning (RL), can be applied to control power systems. We describe some challenges in power ... [more ▼]

In this paper, we explore how a computational approach to learning from interactions, called reinforcement learning (RL), can be applied to control power systems. We describe some challenges in power system control and discuss how some of those challenges could be met by using these RL methods. The difficulties associated with their application to control power systems are described and discussed as well as strategies that can be adopted to overcome them. Two reinforcement learning modes are considered: the online mode in which the interaction occurs with the real power system and the offline mode in which the interaction occurs with a simulation model of the real power system. We present two case studies made on a four-machine power system model. The first one concerns the design by means of RL algorithms used in offline mode of a dynamic brake controller. The second concerns RL methods used in online mode when applied to control a thyristor controlled series capacitor (TCSC) aimed to damp power system oscillations. [less ▲]

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See detailLearning movement patterns in mobile networks: a generic method
François, Jean-Marc; Leduc, Guy ULg; Martin, Sylvain ULg

in European Wireless 2004 (2004, February)

Predicting terminals movements in mobile networks is useful for more than one reason, in particular for routing management. A way to do such prediction is to learn the movement patterns of mobile nodes ... [more ▼]

Predicting terminals movements in mobile networks is useful for more than one reason, in particular for routing management. A way to do such prediction is to learn the movement patterns of mobile nodes passing by an access router. In this paper, the information (e.g. layer 2 measurements) related to the different paths followed by mobiles are learned using a hidden Markov model. Simulations have been done using this method and show it can handle different layer~2 signals and collect statistical information when no such signal is available. Furthermore, the method works when no information is available and can be extended so as to guess the timing of the handoffs. [less ▲]

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See detailLa déchéance d'un droit d'usufruit, d'usage, d'habitation ou d'emphytéose : causes et effets
Vanbrabant, Bernard ULg

in Revue Générale de Droit Civil Belge = Tijdschrift voor Belgisch Burgerlijk (2004), 1

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See detailThe effects of strontium ranelate on the risk of vertebral fracture in women with postmenopausal osteoporosis
Meunier, Pierre J.; Roux, Christian; Seeman, Ego et al

in New England Journal of Medicine (2004), 350(5), 459-468

BACKGROUND: Osteoporotic structural damage and bone fragility result from reduced bone formation and increased bone resorption. In a phase 2 clinical trial, strontium ranelate, an orally active drug that ... [more ▼]

BACKGROUND: Osteoporotic structural damage and bone fragility result from reduced bone formation and increased bone resorption. In a phase 2 clinical trial, strontium ranelate, an orally active drug that dissociates bone remodeling by increasing bone formation and decreasing bone resorption, has been shown to reduce the risk of vertebral fractures and to increase bone mineral density. METHODS: To evaluate the efficacy of strontium ranelate in preventing vertebral fractures in a phase 3 trial, we randomly assigned 1649 postmenopausal women with osteoporosis (low bone mineral density) and at least one vertebral fracture to receive 2 g of oral strontium ranelate per day or placebo for three years. We gave calcium and vitamin D supplements to both groups before and during the study. Vertebral radiographs were obtained annually, and measurements of bone mineral density were performed every six months. RESULTS: New vertebral fractures occurred in fewer patients in the strontium ranelate group than in the placebo group, with a risk reduction of 49 percent in the first year of treatment and 41 percent during the three-year study period (relative risk, 0.59; 95 percent confidence interval, 0.48 to 0.73). Strontium ranelate increased bone mineral density at month 36 by 14.4 percent at the lumbar spine and 8.3 percent at the femoral neck (P<0.001 for both comparisons). There were no significant differences between the groups in the incidence of serious adverse events. CONCLUSIONS: Treatment of postmenopausal osteoporosis with strontium ranelate leads to early and sustained reductions in the risk of vertebral fractures. [less ▲]

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See detailDéveloppement de la lecture chez les enfants trisomiques 21
Comblain, Annick ULg

Conference (2004, January 24)

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See detailLe bilinguisme précoce : implications sur l'acquisition de la langue maternelle orale et écrite
Comblain, Annick ULg

Conference (2004, January 24)

Apprendre à lire dans une langue n’interfère pas avec l’apprentissage de la lecture dans une autre langue mais prépare plutôt le terrain pour apprendre à lire dans une autre langue. Comme dans le langage ... [more ▼]

Apprendre à lire dans une langue n’interfère pas avec l’apprentissage de la lecture dans une autre langue mais prépare plutôt le terrain pour apprendre à lire dans une autre langue. Comme dans le langage oral, il peut y avoir quelques « mixing » de prononciation au niveau des mots qui disparaissent progressivement au fur et à mesure que les langues se compartimentalisent. Avec le temps, l’enfant apprendra également que des mots qui s’écrivent de la même manière dans les deux langues peuvent se prononcer de manière différente. Une recherche menée sur des enfants francophones Belges suivant un programme d’immersion scolaire en anglais et ayant appris à lire en anglais confirment ces observations. 150 enfants âgés de 7 à 12 ans fréquentant ce programme ont été testés sur leurs compétences en lecture du français (décodage et compréhension). Leurs performances (type et nombre d’erreurs, vitesse de lecture) ont été comparées à celles d’enfants francophones fréquentant un enseignement unilingue. Leurs habiletés métaphonologiques (manipulation de la rime et du phonème) ont également été testées. [less ▲]

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See detailPrevention of violence in the sports area: social and educative measures
Comeron, Manuel ULg

Conference (2004, January 23)

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See detailTransparent exopolymer particles and dissolved organic carbon production by Emiliania huxleyi exposed to different CO2 concentrations: a mesocosm experiment
Engel, Anja; Delille, Bruno ULg; Jacquet, Stéphan et al

in Aquatic Microbial Ecology (2004), 34(1), 93-104

The role of transparent exopolymer particles (TEP) and dissolved organic carbon (DOC) for organic carbon partitioning under different CO2 conditions was examined during a mesocosm experiment with the ... [more ▼]

The role of transparent exopolymer particles (TEP) and dissolved organic carbon (DOC) for organic carbon partitioning under different CO2 conditions was examined during a mesocosm experiment with the coccolithophorid Emiliania huxleyi. We designed 9 outdoor enclosures (similar to11 m(3)) to simulate CO2 concentrations of estimated 'Year 2100' (similar to710 ppm CO2), 'present' (similar to410 ppm CO2) and 'glacial' (similar to190 ppm CO2) environments, and fertilized these with nitrate and phosphate to favor bloom development. Our results showed fundamentally different TEP and DOC dynamics during the bloom. In all mesocosms, TEP concentration increased after nutrient exhaustion and accumulated steadily until the end of the study. TEP concentration was closely related to the abundance of E. huxleyi and accounted for an increase in POC concentration of 35 +/- 2 % after the onset of nutrient limitation. The production of TEP normalized to the cell Abundance of E. huxleyi was highest in the Year 2100 treatment. In contrast, DOC concentration exhibited considerable short-term fluctuations throughout the study. In all mesocosms, DOC was neither related to the abundance of E. huxleyi nor to TEP concentration. A statistically significant effect of the CO2 treatment on DOC concentration was not determined. However, during the course of the bloom, DOC concentration increased in 2 of the 3 Year 2100 mesocosms and in 1 of the present mesocosms, but in none of the glacial mesocosms. It is suggested that the observed differences between TEP and DOC were determined by their different bioavailability and that a rapid response of the microbial food web may have obscured CO2 effects on DOC production by autotrophic cells. [less ▲]

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See detailL'influence de l'inné et de l'acquis sur le comportement alimentaire
Blecker, Christophe ULg

Scientific conference (2004, January 13)

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See detailEffects of geographic origin on growth and food intake in Eurasian perch (Perca fluviatilis L.) juveniles under intensive culture conditions
Mandiki, S. N. M.; Blanchard, G.; Mélard, Charles ULg et al

in Aquaculture (2004), 229(1-4), 117-128

Survival, growth, and food intake of Eurasian perch (Perca fluviatilis) juveniles from different stocks originating from various geographic regions of Europe were compared under the same conditions of ... [more ▼]

Survival, growth, and food intake of Eurasian perch (Perca fluviatilis) juveniles from different stocks originating from various geographic regions of Europe were compared under the same conditions of laboratory-scale intensive culture. In Experiment 1, four stocks originating from Italy (1), southwest (SF) and northwest (NF) France, and Belgium (B) were examined at larval and early juvenile (initial body weight, IBW = 0.53 g) stages. In Experiment 2, B stock was compared to a Finnish (F) one in two trials, including small (IBW = 1.26 g) and large (IBW = 32 g) juveniles. In Experiment 3, small (IBW = 1.29 g) and large (IBW = 7.33 g) juveniles from Polish (P), F, and B stocks were examined. In Experiment 1, body weight means at hatching and survival at the end of the larval stage were significantly lower in the I and SF stocks than in the B and NF stocks. In the early juvenile stage, survival and growth rates were significantly lower in the I and SF stocks than in the B and NF ones. In Experiment 2, {early juvenile stage} survival in the F stock was significantly lower than in the B stock, partly due to a higher incidence of cannibalism. During this stage, growth rates and food intake or feed efficiency in the F and B stocks were comparable, but at the end of the juvenile stage, the F stock outperformed the B one. In Experiment 3, survival in all the three stocks was comparable both in small and large juveniles. In contrast to the higher performance of F juveniles in Experiment 2, growth rates were comparable between the B and F stocks, and fish from the P stock had the highest growth rates. The results indicate a high level of variation within and between hatchery stocks in survival rates, growth rates, and food intake. These variations depended on the geographic origin of the fish, with the lowest survival and growth potentials being in the stocks originating from the southern regions. These findings highlight the interest in evaluating growth and food consumption of different Eurasian perch stocks. Such evaluation is a necessary tool for genetic selection in improving performance in perch aquaculture. (C) 2004 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailL'édition à l'heure des trous noirs
Durand, Pascal ULg

in Acrimed (2004)

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See detailThe maximum deviation just-in-time scheduling problem
Brauner, Nadia; Crama, Yves ULg

in Discrete Applied Mathematics (2004), 134(1-3), 25-50

This note revisits the maximum deviation just-in-time (MDJIT) scheduling problem previously investigated by Steiner and Yeomans. Its main result is a set of algebraic necessary and sufficient conditions ... [more ▼]

This note revisits the maximum deviation just-in-time (MDJIT) scheduling problem previously investigated by Steiner and Yeomans. Its main result is a set of algebraic necessary and sufficient conditions for the existence of a MDJIT schedule with a given objective function value. These conditions are used to provide a finer analysis of the complexity of the MDJIT problem. The note also investigates various special cases of the MDJIT problem and suggests several questions for further investigation. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailA new process for the synthesis of alkoxyamines active in controlled radical polymerization
Detrembleur, Christophe ULg; Gross, Thomas; Meyer, Rolf-Volker

Patent (2004)

The present invention relates to a new process for the preparation of alkoxyamine initiators and to a process of radical polymerization using the alkoxyamine initiators as intermediates.

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See detailOne-pot process for the preparation of functionalized alkoxyamines
Detrembleur, Christophe ULg; Gross, Thomas; Meyer, Rolf-Volker

Patent (2004)

The present invention relates to a new one-pot process for the preparation of functionalized alkoxyamine initiators of the formula (I) <CHEM> from amines of the formula (II) <CHEM> and to a process of ... [more ▼]

The present invention relates to a new one-pot process for the preparation of functionalized alkoxyamine initiators of the formula (I) <CHEM> from amines of the formula (II) <CHEM> and to a process of controlled radical polymerization using the functionalized alkoxyamine as initiators. In the above formulae, R<1>-R<5> have the meanings given in the description. [less ▲]

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See detailMolecular basis of the amylose-like polymer formation catalyzed by Neisseria polysaccharea amylosucrase
Albenne, C.; Skov, L. K.; Mirza, O. et al

in Journal of Biological Chemistry (2004), 279(1), 726-734

Amylosucrase from Neisseria polysaccharea is a remarkable transglucosidase from family 13 of the glycosidehydrolases that synthesizes an insoluble amylose-like polymer from sucrose in the absence of any ... [more ▼]

Amylosucrase from Neisseria polysaccharea is a remarkable transglucosidase from family 13 of the glycosidehydrolases that synthesizes an insoluble amylose-like polymer from sucrose in the absence of any primer. Amylosucrase shares strong structural similarities with alpha-amylases. Exactly how this enzyme catalyzes the formation of alpha-1,4-glucan and which structural features are involved in this unique functionality existing in family 13 are important questions still not fully answered. Here, we provide evidence that amylosucrase initializes polymer formation by releasing, through sucrose hydrolysis, a glucose molecule that is subsequently used as the first acceptor molecule. Maltooligosaccharides of increasing size were produced and successively elongated at their nonreducing ends until they reached a critical size and concentration, causing precipitation. The ability of amylosucrase to bind and to elongate maltooligosaccharides is notably due to the presence of key residues at the OB1 acceptor binding site that contribute strongly to the guidance ( Arg(415), subsite +4) and the correct positioning (Asp(394) and Arg(446), subsite +1) of acceptor molecules. On the other hand, Arg(226) (subsites +2/+3) limits the binding of maltooligosaccharides, resulting in the accumulation of small products (G to G3) in the medium. A remarkable mutant (R226A), activated by the products it forms, was generated. It yields twice as much insoluble glucan as the wild-type enzyme and leads to the production of lower quantities of by-products. [less ▲]

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See detailSynthesis and evaluation of N1/C4-substituted beta-lactams as PPE and HLE inhibitors
Gérard, Stéphane; Galleni, Moreno ULg; Dive, Georges ULg et al

in Bioorganic & Medicinal Chemistry (2004), 12(1), 129-138

4-(Alkylamino)carbonyl-1-(alkoxy)carbonyl-2-azetidinones (9-11) have been prepared in five steps from 4-(benzyloxy)carbonyl-1-(t-butyidimethyl)silyl-2-azetidinone (1). The P-lactam reactivity of 9 has ... [more ▼]

4-(Alkylamino)carbonyl-1-(alkoxy)carbonyl-2-azetidinones (9-11) have been prepared in five steps from 4-(benzyloxy)carbonyl-1-(t-butyidimethyl)silyl-2-azetidinone (1). The P-lactam reactivity of 9 has been established by H-1 NMR experiment. Compound 11 was a good reversible inhibitor of PPE and HLE. Based on theoretical design, series of 2-azetidinones (12-17) and 4(alkoxy)carbonyl-2-azetidinones (18-21) bearing various carbonyl (ester, thiolester, amide) and thiocarbonyl (thioamide) functionalities at position N1 were similarly prepared. In the absence of C4-substituent, the compounds were inactive against elastases. On the other hand, 4-(benzyloxy)carbonyl-1-(ethylthioxy)carbonyl-2-azetidinone (19) and 4-(benzyloxy)carbonyl-1-(benzylamino)-thiocarbonyl-2-azetidinone (21) were both good reversible inhibitors, but acting most probably via different mechanisms (enzymic processing of the exocyclic ester function or beta-lactam ring opening). (C) 2003 Elsevier Ltd. All rights reserved. [less ▲]

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