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See detailLink between learning profile and school achievement in primary school; a transversal study
Frenkel, Stéphanie ULg; Nobile, Debora ULg

Conference (2014, July)

School achievement plays an essential role in terms of professional and social adaptation. However, all the students do not always perform as the system requires them to. In Belgium, at the end of ... [more ▼]

School achievement plays an essential role in terms of professional and social adaptation. However, all the students do not always perform as the system requires them to. In Belgium, at the end of compulsory education, one student out of two lags behind in their school education (Indicators from the Fédération Wallonie-Bruxelles [Walloon-Brussels Federation], 2012). In this context, we do not consider that there are “bad” learners. Instead, there are those students whose learning profile is more or less in line with the context’s requirements and those whose profile is not. In many works, the student’s learning profile is operationalised by measures on 3 levels: cognitive, metacognitive and psycho-affective. These psychological variables, which are major components of self-regulated learning, play a central role in the explanation of school performance (for more details, see Frenkel, in press; Frenkel & Deforge, in press). This profile is not fixed once and for all. It evolves over time and it represents the result of the interaction between these three variables with other factors, notably bio-medical, socio-demographical ones, factors related to family environment (Pourtois, Desmet & Lahaye, 2004; Trudel, Puentes-Neuman & Ntebutse, 2002) and the too often forgotten factors linked to class management and social interactions between students and teachers (see Wang, Haertel & Walberg, 1994). Determining the students’ learning profile enables us to identify their strengths and work on their weaknesses. Therefore, it is essential that psycho-educational teams have validated tools at their disposal in order to carry out this task. Our aim is to propose new tools which will complement the already-existing ones. In this presentation we propose to introduce and discuss our methodology and the results obtained. The starting target population was made up of 198 primary school students divided equitably into three levels (second year of primary school, fourth year of primary school and sixth year of primary school). A problem-solving task based on the DELF (Büchel & Büchel, 1995) was created. It was completed by two questionnaires to fill in before and after the task. The learning profile defined on this basis was analysed according to several variables (age, gender, socio-professional category, school results). Group testing is still in progress. We will also illustrate our presentation with the first results of individual testing which will begin in May 2014. References - Büchel, F.P. & Büchel, P. (1995). Découvrez vos capacités, rEalisez vos possibilités, pLanifiez votre démarche, soyez créatiFs. Le programme DELF. Russin, Switzerland: Centre d’éducation cognitive - Frenkel, S. (in press). Metacognitive components in learning to learn approaches. International Journal of Psychology: A Biopsychosocial Approach - Frenkel, S., & Deforge, H. (in press). Métacognition et réussite scolaire: Perspectives théoriques. In C. Giraudeau & G. Chasseigne (Eds.), Psychologie, Education et Vie scolaire. Tours, France: Editions Publibook Université - Pourtois, J.-P., Desmet, H., & Lahaye, W. (2004). Connaissances et pratiques en éducation familiale et parentale. Enfances, Familles, Générations, 1, 22-35 - Trudel, M., Puentes-Neuman, G., & Ntebutse J.G. (2002). Les conceptions contemporaines de l’enfant à risque et la valeur heuristique du construit de résilience en éducation. Revue Canadienne de l’Education, 27 (2 & 3), 153-173 - Wang, M.C., Haertel, G.D., & Walberg, H.J. (1994). What helps students learn? Educational Leadership, 51 (4), 74-79 [less ▲]

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See detailHD 97658 and its super-Earth. Spitzer & MOST transit analysis and modeling of the host star
Van Grootel, Valérie ULg; Gillon, Michaël ULg; Valencia, D. et al

Conference (2014, July)

Super-Earths transiting nearby bright stars are key objects that simultaneously allow for accurate measurements of both their mass and radius, providing essential constraints on their internal composition ... [more ▼]

Super-Earths transiting nearby bright stars are key objects that simultaneously allow for accurate measurements of both their mass and radius, providing essential constraints on their internal composition. We present here the confirmation, based on Spitzer transit observations, that the super-Earth HD 97658 b transits its host star. HD 97658 is a low-mass ($M_*=0.77\pm0.05\,M_{\odot}$) K1 dwarf, as determined from the Hipparcos parallax and stellar evolution modeling. To constrain the planet parameters, we carry out Bayesian global analyses of Keck-HIRES radial velocities, and MOST and Spitzer photometry. HD 97658 b is a massive ($M_P=7.55^{+0.83}_{-0.79} M_{\oplus}$) and large ($R_{P} = 2.247^{+0.098}_{-0.095} R_{\oplus}$ at 4.5 $\mu$m) super-Earth. We investigate the possible internal compositions for HD 97658 b. Our results indicate a large rocky component, by at least 60% by mass, and very little H-He components, at most 2% by mass. We also discuss how future asteroseismic observations can improve the knowledge of the HD 97658 system, in particular by constraining its age. Orbiting a bright host star, HD 97658 b will be a key target for coming space missions TESS, CHEOPS, PLATO, and also JWST, to characterize thoroughly its structure and atmosphere. [less ▲]

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See detailEconomic Statistical Design of the VP( X) ̅ Control Charts for Monitoring a Process under Non-normality
Seif, Asghar; Faraz, Alireza ULg; Saniga, Erwin

E-print/Working paper (2014)

Recent studies proved that variable parameters (VP) X ̅ control charts not only detects process mean shifts quicker than the classical X ̅ control chart but also has better economic properties ... [more ▼]

Recent studies proved that variable parameters (VP) X ̅ control charts not only detects process mean shifts quicker than the classical X ̅ control chart but also has better economic properties. Furthermore, like most papers in control chart design, the fundamental assumption is that process data are normally distributed. Nevertheless, process quality variables may not be normal in application. In this paper, we investigate the economic statistical design of the VP X ̅ control chart when the underlying process distribution is non-normal. We illustrate the design procedure and perform a sensitivity analysis on the process and cost parameters based upon the degrees of skewness and kurtosis of the population using an industrial application. [less ▲]

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See detailMagnetic characterisation of large grain, bulk Y–Ba–Cu–O superconductor–soft ferromagnetic alloy hybrid structures
Philippe, Matthieu ULg; Fagnard, Jean-François ULg; Kirsch, Sébastien ULg et al

in Physica C: Superconductivity (2014), 502

Large grain, bulk Y–Ba–Cu–O (YBCO) high temperature superconductors (HTS) have significant potential for use in a variety of practical applications that incorporate powerful quasi-permanent magnets. In ... [more ▼]

Large grain, bulk Y–Ba–Cu–O (YBCO) high temperature superconductors (HTS) have significant potential for use in a variety of practical applications that incorporate powerful quasi-permanent magnets. In the present work, we investigate how the trapped field of such magnets can be improved by combining bulk YBCO with a soft FeNi, ferromagnetic alloy. This involves machining the alloy into components of various shapes, such as cylinders and rings, which are attached subsequently to the top surface of a solid, bulk HTS cylinder. The effect of these modifications on the magnetic hysteresis curve and trapped field of the bulk superconductor at 77 K are then studied using pick-up coil and Hall probe measurements. The experimental data are compared to finite element modelling of the magnetic flux distribution using Campbell’s algorithm. Initially we establish the validity of the technique involving pick-up coils wrapped around the bulk superconductor to obtain its magnetic hysteresis curve in a non-destructive way and highlight the difference between the measured signal and the true magnetization of the sample. We then consider the properties of hybrid ferromagnet/superconductor (F/S) structures. Hall probe measurements, together with the results of the model, establish that flux lines curve outwards through the ferromagnet, which acts, effectively, like a magnetic short circuit. Magnetic hysteresis curves show that the effects of the superconductor and the ferromagnet simply add when the ferromagnet is saturated fully by the applied field. The trapped field of the hybrid structure is always larger than that of the superconductor alone below this saturation level, and especially when the applied field is removed. The results of the study show further that the beneficial effects on the trapped field are enhanced when the ferromagnet covers the entire surface of the superconductor for different ferromagnetic components of various shapes and fixed volume. [less ▲]

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See detailViBe: A Disruptive Method for Background Subtraction
Van Droogenbroeck, Marc ULg; Barnich, Olivier

in Bouwans; Porikli; Hoferlin (Eds.) et al Background Modeling and Foreground Detection for Video Surveillance (2014)

This chapter presents ViBe and the underlying ideas of the algorithm. ViBe is an algorithm for the dection of motion by background subtraction. It is a very fast algorithm, based on samples and several ... [more ▼]

This chapter presents ViBe and the underlying ideas of the algorithm. ViBe is an algorithm for the dection of motion by background subtraction. It is a very fast algorithm, based on samples and several innovative processes (time subsampling, random substitution, spatial diffusion, etc). In addtion, we propose a way to measure the computation time by introducing the notion of complexity factor. [less ▲]

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See detailStability and bifurcation analysis of a Van der Pol–Duffing oscillator with a nonlinear tuned vibration absorber
Habib, Giuseppe ULg; Kerschen, Gaëtan ULg

Conference (2014, July)

The Van der Pol (VdP) oscillator is a paradigmatic model for description of self-excited oscillations, which are of practical interest in many engineering applications. In this paper the dynamics of a VdP ... [more ▼]

The Van der Pol (VdP) oscillator is a paradigmatic model for description of self-excited oscillations, which are of practical interest in many engineering applications. In this paper the dynamics of a VdP-Duffing (VdPD) oscillator with an attached nonlinear tuned vibration absorber (NLTVA) is considered; the NLTVA has both linear and nonlinear restoring force terms. In the first part of this work, the stability of the trivial solution of the system is investigated, following results of previous works. The analysis allows to define an optimal tuning rule for the linear parameters of the absorber, which substantially enlarges the domain of safe operation of the primary system. In this case, the system loses stability through a double Hopf bifurcation. In the second part of this work, the bifurcations occurring at the loss of stability are analytically investigated, using the technique of the center manifold reduction and transformation to normal form. The obtained results show the effects of the nonlinear parameter of the absorber, which, in turn, allows to define its optimal value in order to avoid subcriticality and reduce the amplitude of self-excited oscillations. [less ▲]

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See detailLa flexicurité : vers une carrière transitionnelle?
Beuker, Laura ULg

Conference (2014, July)

Ces dernières années, les institutions Européennes ont joué un rôle clé dans la régulation et l’orientation des politiques publiques pour l’emploi des États-membres (Amparo-Serrano et Martin-Martin, 2012 ... [more ▼]

Ces dernières années, les institutions Européennes ont joué un rôle clé dans la régulation et l’orientation des politiques publiques pour l’emploi des États-membres (Amparo-Serrano et Martin-Martin, 2012). Dans ce cadre, la flexicurité s’est imposée comme une référence des politiques en matière de droit du travail, d’emploi, de sécurité sociale et de formation professionnelle (Conter et Orianne, 2011). En Belgique, cette exigence d’allier flexibilité et sécurité sur le marché du travail a constitué le cœur de nombreux discours et programmes politiques, pour finir par s’estomper progressivement, à la suite de crises financières et économiques l’ayant fortement éprouvé. Ce « concept » a-t-il pour autant effectivement disparu ? À partir d’une étude qualitative basée sur des entretiens semi-directifs menés auprès d’acteurs institutionnels – experts et analystes du marché du travail – nous nous sommes rendu compte que si la sémantique n’est plus, les principes de flexicurité sont, quant à eux, toujours présents dans le discours des individus. De plus, ces principes semblent détenir une portée normative de taille quant à la redéfinition de l’articulation des temporalités sociales : d’une sécurité de l’emploi, nous serions en train d’effectuer un glissement vers une sécurité en emploi de l’individu. La rhétorique n’est pas innocente : désormais, ce n’est plus tant l’individu qu’il s’agit de protéger (droit du travail, etc.) mais bien les transitions – multiples et sinueuses – opérées par ce dernier. Pour y parvenir, l’État le responsabilise : il doit désormais être capable de se prendre en mains : « c’est le passage d’un ‘État qui protège’ à un ‘État qui rend capable’ » (Vrancken, 2008). [less ▲]

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See detailNegation, grammaticalization and subjectification: the development of polar, modal and mirative no way-constructions
Davidse, Kristin; Brems, Lieselotte ULg; Lesage, Jakob et al

Conference (2014, July)

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

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

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See detailCO2 fluxes across the air-ice interface
Delille, Bruno ULg

Conference (2014, July)

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See detailKeep the nest clean: survival advantages of corpse removal in ants
Diez, Lise; Lejeune, Philippe ULg; Detrain, Claire

in Biology Letters (2014), 10(7),

Sociality increases exposure to pathogens. Therefore, social insects have developed a wide range of behavioural defences, known as ‘social immunity’. However, the benefits of these behaviours in terms of ... [more ▼]

Sociality increases exposure to pathogens. Therefore, social insects have developed a wide range of behavioural defences, known as ‘social immunity’. However, the benefits of these behaviours in terms of colony survival have been scarcely investigated. We tested the survival advantage of prophylaxis, i.e. corpse removal, in ants. Over 50 days, we compared the survival of ants in colonies that were free to remove corpses with those that were restricted in their corpse removal. From Day 8 onwards, the survival of adult workers was significantly higher in colonies that were allowed to remove corpses normally. Overall, larvae survived better than adults, but were slightly affected by the presence of corpses in the nest. When removal was restricted, ants removed as many corpses as they could and moved the remaining corpses away from brood, typically to the nest corners. These results show the importance of nest maintenance and prophylactic behaviour in social insects. [less ▲]

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See detailUsuing the Arctic Environment Test Basin to study the dynamics of dissolved organic matter in sea ice
Thomas, D.N.; Zhou, Jiayun ULg; Kaartokallio, H. et al

Conference (2014, July)

This is a report from the INTERICE 5 project that used the Arctic Environment Test Basin at HSVA from 21 May to 19 June 2012. The overarching aim was to investigate the physical and biological controls of ... [more ▼]

This is a report from the INTERICE 5 project that used the Arctic Environment Test Basin at HSVA from 21 May to 19 June 2012. The overarching aim was to investigate the physical and biological controls of dissolved organic matter incorporation into growing sea ice and the effect of melting once the ice had consolidated. Measurements were also made on the CO2 fluxes at the ice surface in relation to the chemical and biological changes taking place in the ice. The Interice 5 team was a multidisciplinary group of glaciologists, chemists and microbiologists from Belgium, Denmark, Finland, Germany and U.K. They were able to build on the experiences of previous INTERICE 2, 3 & 4 projects to maximize the opportunities from the facility. The preliminary results from the experiment will be presented, in the context of what is known about these processes from field campaigns. [less ▲]

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See detail3D MODELING OF SHEAR STRESS DEVELOPMENT DURING NEOTISSUE GROWTH IN A PERFUSION BIOREACTOR
Guyot, Yann ULg; Papantoniou, Ioannis; Schrooten, Jan et al

Conference (2014, July)

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See detailA Multiphycics approach to calculate shear stresses during neotissue growth in perfusion bioreactor
Guyot, Yann ULg; Papantoniou, Ioannis; Schrooten, Jan et al

Conference (2014, July)

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See detailA parent-implemented language intervention in lower socioeconomic status populations
Martinez Perez, Trecy ULg; Leclercq, Anne-Lise ULg; Mulquet, Amandine et al

Poster (2014, July)

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

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

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

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

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See detailSentence repetition task as a powerful diagnostic tool in French children with SLI
Leclercq, Anne-Lise ULg

Poster (2014, July)

Sentence repetition is considered as a psycholinguistic marker of specific language impairment (SLI) (i.e., Redmond et al., 2011). However, little is known about specificity and sensitivity for most ... [more ▼]

Sentence repetition is considered as a psycholinguistic marker of specific language impairment (SLI) (i.e., Redmond et al., 2011). However, little is known about specificity and sensitivity for most language tests, especially in French (Thordardottir et al., 2011). This study aims at assessing the specificity and sensitivity of a sentence repetition task frequently used in clinical evaluations (Chevrie-Muller et al., 2010). This task could be especially interesting because clinicians can compute separate linguistic scores depending on the answers produced by the children, enabling them to get a glimpse of the areas of language difficulties in these children. Fourty-four school-age children with SLI, and 34 age-and-IQ-matched controls participated in this study. Children with SLI were diagnosed by certified speech-language pathologists and attained specific language classes in special needs schools from at least one year. Moreover, they scored more than -1.25 SD below expected normative performance in at least 2 language areas on other standardised tests used in previous studies including French children with SLI. Results show that both sensitivity and specificity of general scores were high (over 80%) at three cut-off points widely used in clinical practice: -1SD, -1.25 SD, -2 SD. Moreover, an exploratory factorial analysis indicates that two distinct factors can be dissociated in children productions: a morphosyntactic factor and a lexico-semantic factor, together explaining 96.48% of the variance in production scores. These results reveal that the sentence repetition task is a powerful diagnostic tool in French children with SLI. [less ▲]

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