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See detailUsing Proper Orthogonal Decomposition Methods for Comparing CFD Results to Experimental Measurements
Andrianne, Thomas ULg; Guissart, Amandine ULg; Terrapon, Vincent ULg et al

Scientific conference (2012, December 07)

This work presents a method for quantitative comparison of numerical results to experimental measurements. It is based on the concept of Proper Orthogonal Decomposition. This technique is selected in ... [more ▼]

This work presents a method for quantitative comparison of numerical results to experimental measurements. It is based on the concept of Proper Orthogonal Decomposition. This technique is selected in order to compare the unsteady aerodynamic flows around static and oscillating bodies obtained from wind tunnel testing and numerical simulations. Two dimensional Time-resolved Particle Image Velocimetry measurements are carried out on the upper surface a 4:1 rectangular cylinder. Simulations are performed using unsteady Reynolds-Averaged Navier-Stokes and an unsteady Discrete Vortex Method. It is demonstrated that the proposed technique is a good preliminary step for comparing the main characteristics of unsteady aerodynamic data. [less ▲]

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See detailnon invasive estimation of left atrial pressure and mitral valve area waveforms during an entire cardiac cycle
Paeme, Sabine ULg; Pironet, Antoine ULg; LANCELLOTTI, Patrizio ULg et al

in proceeding of 11th national day of the National Committee on Biomedical Engineering (2012, December 07)

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See detailEfficient ALE mesh management for 3D quasi-Eulerian problems
Boman, Romain ULg; Ponthot, Jean-Philippe ULg

in International Journal for Numerical Methods in Engineering (2012), 92(10), 857-890

In computational solid mechanics, the ALE formalism can be very useful to reduce the size of finite element models of continuous forming operations such as roll forming. The mesh of these ALE models is ... [more ▼]

In computational solid mechanics, the ALE formalism can be very useful to reduce the size of finite element models of continuous forming operations such as roll forming. The mesh of these ALE models is said to be quasi-Eulerian because the nodes remain almost fixed—or almost Eulerian—in the main process direction, although they are required to move in the orthogonal plane in order to follow the lateral displacements of the solid. This paper extensively presents a complete node relocation procedure dedicated to such ALE models. The discussion focusses on quadrangular and hexahedral meshes with local refinements. The main concern of this work is the preservation of the geometrical features and the shape of the free boundaries of the mesh. With this aim in view, each type of nodes (corner, edge, surface and volume) is treated sequentially with dedicated algorithms. A special care is given to highly curved 3D surfaces for which a CPU-efficient smoothing technique is proposed. This new method relies on a spline surface reconstruction, on a very fast weighted Laplacian smoother with original weights and on a robust reprojection algorithm. The overall consistency of this mesh management procedure is finally demonstrated in two numerical applications. The first one is a 2D ALE simulation of a drawbead, which provides similar results to an equivalent Lagrangian model yet is much faster. The second application is a 3D industrial ALE model of a 16-stand roll forming line. In this case, all attempts to perform the same simulation by using the Lagrangian formalism have been unsuccessful. [less ▲]

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See detailPiezocision-assisted orthodontic treatment in adult patient: A case report
CHARAVET, Carole ULg; LAMBERT, France ULg; LECLOUX, Geoffrey ULg et al

Conference (2012, December 07)

The duration of orthodontic treatments in adult patient remains a barrier for some patients. The recent scientific reports describing piezocision technique involving minimally invasive corticotomies, seem ... [more ▼]

The duration of orthodontic treatments in adult patient remains a barrier for some patients. The recent scientific reports describing piezocision technique involving minimally invasive corticotomies, seem to be of interest for these particular cases. The present communication describes the clinical case of a 20-year-old patient presenting a class I bilateral, an overcrowding of front areas with the superior canine in mesio-infraclusion and a deviated lower median line. An excellent multidisciplinary approach is mandatory for the planification of such cases. Under local anesthesia, the surgical technique involves vertical minimal incision around the teeth that need to be moved. Trough the minimal incisions, 5mm vertical alveolar osteotomies are performed using ultrasonic surgical device. No suture is necessary. The orthodontic activation is applied 1 week before the surgical procedure and the patient is recalled every 15 days to activate the orthodontic appliance. In this case self-ligating brackets were used to reduce the friction. Post-operative outcomes were painless for the patient and the complete orthodontic procedure took 7 months. The overall treatment appeared to be faster than a conventional orthodontic treatment. However, even if animal studies seem to confirm the clinical feeling described in this case report, further clinical studies including randomized controlled trials are needed to validate this treatment approach. [less ▲]

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See detailLa littérature scientifique dans la formation des bioingénieurs à Gembloux. Vingt années d'évolution du concept d'Information Literacy
Pochet, Bernard ULg

Doctoral thesis (2012)

In the education of bioengineers at Gembloux, the concept of information literacy was chosen as a guide for information literacy education. This concept describes a set of skills that allow individuals to ... [more ▼]

In the education of bioengineers at Gembloux, the concept of information literacy was chosen as a guide for information literacy education. This concept describes a set of skills that allow individuals to recognize an information need and enable them to locate, evaluate and use information needed. The concept of information literacy has evolved over the last two decades. This essay traces, through five articles and a review of the literature on the subject, the evolution of the concept. It also presents ways to implement information literacy education with a methodological approach, starting by the identification of the need of information to solve a problem to the production of a scientific communication (a homework, a conference, a scholarly paper...). This work addresses also the question of the relative invisibility of the concept of information literacy outside information specialists such as librarians. The major objective is to demonstrate that information literacy education is going well beyond the library. The skills involved are also intellectual, social and cultural skills. They include media and new information technologies and are not limited to technical or technological skills. Information literacy has become an autonomous discipline, with specific content, evolving, to talk about a didactic. Information literacy courses held in Gembloux should be considered as tools to improve the training of bioengineers and particularly the quality of their scientific publications. [less ▲]

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See detailBiorthogonalization Techniques for Least Squares Temporal Difference Learning
Jung, Tobias ULg; Ernst, Damien ULg

Poster (2012, December 07)

We consider Markov reward processes and study OLS-LSTD, a framework for selecting basis functions from a set of candidates to obtain a sparse representation of the value function in the context of least ... [more ▼]

We consider Markov reward processes and study OLS-LSTD, a framework for selecting basis functions from a set of candidates to obtain a sparse representation of the value function in the context of least squares temporal difference learning. To support efficient both updating and downdating operations, OLS-LSTD uses a biorthogonal representation for the selected basis vectors. Empirical comparisons with the recently proposed MP and LARS frameworks for LSTD are made. [less ▲]

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See detailMens immobilis. Recherches sur le corpus latin des actes et passions d'Afrique romaine (IIe-VIe siècles)
Fialon, Sabine ULg

Doctoral thesis (2012)

This thesis focuses on a corpus of thirty hagiographical texts from Roman North Africa, dated from the second to the sixth century. None synthesis on this corpus had been made since P. Monceaux’s work in ... [more ▼]

This thesis focuses on a corpus of thirty hagiographical texts from Roman North Africa, dated from the second to the sixth century. None synthesis on this corpus had been made since P. Monceaux’s work in the early twentieth century. In the first part, all the latin texts were collected, together with a translation and an exhaustive research of the sources : for many of them I gave a new critical edition, and a new text, the long recension of the Passion of Marciana, has been discovered. This corpus is then studied from an historical point of view. The first two sections examine these texts as evidence of the christianization of Africa, through the study of the complex phenomenon of persecutions and martyrdom. The third part illustrates the multiple potentialities of hagiographic discourse, which tends to make a new Christian hero, combination of pagan hero and of the theme of Judeo-Hellenistic Just suffering. The latter addresses the corpus as evidence of the literary culture of African elites and contributes to the cultural history of North Africa and of the circulation of ideas and works. It also discusses the question of the africitas, according to the methods of the LASLA of the University of Liège, methods applied to three passions of Caesarean Mauretania. [less ▲]

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See detailAbundance and phenological model of Harmonia axyridis (Coleoptera: Coccinellidae) in field crops
Vandereycken, Axel ULg; Brostaux, Yves ULg; Joie, Emilie ULg et al

Poster (2012, December 07)

The multicolored Asian ladybeetle Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) was introduced into Western Europe in the late 1990s. This exotic and invasive species is known to thrive ... [more ▼]

The multicolored Asian ladybeetle Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) was introduced into Western Europe in the late 1990s. This exotic and invasive species is known to thrive principally in shrubs and arboreal habitats. We focus on a phonological model and on annual abundance in various field crops. The abundance of H. axyridis adults and larvae were evaluated during a three-year period, from 2009 to 2011, in four important agronomical crops (wheat, corn, broad bean and potato) in Belgium. H. axyridis colonizes and reproduces in all four crops studied, with larger densities observed in corn and broad bean. The reproduction of H. axyridis occurs principally in corn and occurred much less in wheat and potato. From 2009 to 2011, abundances of H. axyridis populations were constant except in corn, where the observed densities of all immature stages and adults were higher in 2011 than in 2009. The population dynamics of aphids and H. axyridis were characterized by a symmetric logistic function (S-shape) based on the cumulative population size. [less ▲]

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See detailLes trois premiers miliards d’années d’évolution de la vie
Javaux, Emmanuelle ULg

Conference (2012, December 07)

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See detailQuelques constats sur le devenir des métiers industriels
Remy, Céline ULg

Conference given outside the academic context (2012)

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See detailStructure et fonction des communautés phytoplanctoniques en milieux côtiers marin et lagunaire (Méditerranée – Corse) dans une optique de gestion
Garrido, Marie ULg

Doctoral thesis (2012)

Les écosystèmes côtiers contribuent de manière importante à la production primaire des océans. De par leur position géographique, ils sont particulièrement sensibles à l’eutrophisation. Le compartiment ... [more ▼]

Les écosystèmes côtiers contribuent de manière importante à la production primaire des océans. De par leur position géographique, ils sont particulièrement sensibles à l’eutrophisation. Le compartiment phytoplanctonique y joue un rôle prépondérant au regard de sa position dans la chaîne tropique, mais également en termes de diversité. Il est également capable d’intégrer et/ou de refléter les changements environnementaux qui s’opèrent à court, moyen et long terme. Cette thèse vise à renforcer les connaissances sur la dynamique et la fonction des communautés phytoplanctoniques par rapport aux conditions environnementales dans deux écosystèmes côtiers, en utilisant des techniques traditionnelles comme la microscopie, l’HPLC et d’autres plus récentes comme le Phyto-PAM et la FluoroProbe. Le littoral corse a été choisi comme site d’étude. En effet, ses 1 047 km de côtes regorgent d’écosystèmes particulièrement dynamiques, d’une richesse biologique importante et de zones d’interfaces productives (e.g. structure frontale, milieu lagunaire). Malgré cela, il existe peu de données concernant la dynamique et la fonction de ces micro-algues, aussi bien en milieu marin côtier que lagunaire. Une fréquence d’échantillonnage appropriée à l’échelle d’observation a été utilisée selon les écosystèmes étudiés et le type d’étude menée (in situ ou expérimentale), allant de prélèvements mensuels à des prélèvements journaliers. Dans un premier temps, nous avons poursuivi les efforts engagés depuis plusieurs années concernant l’amélioration des méthodes d’analyses spectrofluorimétriques nécessaires pour l’étude de la dynamique et l’analyse fonctionnelle des communautés phytoplanctoniques. Des recommandations concernant les conditions de conservation des échantillons (i.e. durée, température) ont été dégagées pour l’analyse au Phyto-PAM, afin d’affiner les limites d’utilisation de cet outil. Nous avons également testé l’utilisation de la FluoroProbe dans les écosystèmes côtiers en Méditerranée. Dans un second temps, nous avons étudié la variabilité spatio-temporelle des communautés phytoplanctoniques en milieu marin côtier (Calvi et Bastia) et en milieu lagunaire eutrophisé (Réserve Naturelle de Biguglia). Les résultats ont mis en avant une succession écologique et une structure des peuplements phytoplanctoniques différentes dans les deux écosystèmes marins côtiers étudiés, présentant des spécificités locales propres et comparés à l’échelle des zones côtières en Méditerranée. Nous avons démontré que des événements météorologiques pouvaient influencer les variations observées, agissant directement sur l’abondance des espèces ou indirectement sur les conditions du milieu (e.g. nutriments). Au niveau lagunaire, les actions de gestion mises en œuvre ont impacté la structure et l'efficacité photosynthétique des communautés phytoplanctoniques. Les modifications des flux hydrologiques ont exacerbé le caractère confiné de la lagune et des efflorescences successives d’espèces opportunistes et non profitables au réseau trophique supérieur ont été observées. Ces études ont permis de fournir une aide scientifique en ce qui concerne la prise de décision qui incombe aux acteurs de l’environnement et plus particulièrement les gestionnaires, dans une optique de gestion. [less ▲]

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See detailPistes pour une mesure de la compétence numérique
Vandeput, Etienne ULg; Henry, Julie ULg

in Questions Vives : Recherches en Education (2012), 7(17),

Nowadays, in the educational field, digital literacy is considered absolutely necessary for students and citizens. If it is occasionally easy to observe the good practice of learners, there remains to ... [more ▼]

Nowadays, in the educational field, digital literacy is considered absolutely necessary for students and citizens. If it is occasionally easy to observe the good practice of learners, there remains to determine how to train them and how to certify their abilities. The visaTICE project tries to face both issues. In this project, certification is a big challenge, but another challenge is to set up a system that takes into account the school context but that is not constrained by it. Presently the visaTICE project has developed online courses, tests, ability trees, coach training programs, which can be used in different contexts but we are not able to prove now, neither the training efficiencies, nor the suitability of the certification tests. A significant number of students will participate in the certification test for the first time in May 2012. Up to now, the collaborative design principle applied in visaTICE acts as a warranty. [less ▲]

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See detailUnderstanding the 3D morphology of the Jovian aurora using Juno-UVS observations: simulations and tomographic reconstruction
Bonfond, Bertrand ULg; Gladstone, Randy

Conference (2012, December 06)

The aurora at Jupiter is a spectacular signature of the many processes taking place in the Jovian magnetosphere, such as magnetic reconnection, large scale electric currents, moon-magnetosphere ... [more ▼]

The aurora at Jupiter is a spectacular signature of the many processes taking place in the Jovian magnetosphere, such as magnetic reconnection, large scale electric currents, moon-magnetosphere interactions, etc. As a consequence, this aurora is extremely complex and dynamic, powered by a variety of phenomena that we have only begun to unravel. The 3D morphology of the aurora can provide a way to untangle the different processes at play. As a polar orbiter, Juno will provide unprecedented global and close-up views of Jupiter’s auroral emissions. As it flies at low altitude over auroral curtains, spots and patches, it will provide views of these features from multiple points, allowing the retrieval of their 3D structure. The ultraviolet spectrograph on board Juno (Juno-UVS) is designed to observe auroral emissions in the 68 to 210 nm range. It is equipped with a scan mirror targeting up to +/-30 degrees off axis of the spacecraft rotation plane. We have built a planning tool to determine which auroral targets of interest, such as a satellite footprint for example, is observable by the instrument at any time during the mission. We have also built a simulation tool that allows us to generate realistic views of the Jovian aurora as observed by Juno-UVS. The purpose of this tool is to 1) fine-tune the selection algorithm to identify the most valuable data in the harsh radiation environment encountered around Jupiter, and 2) serve as a test bed for adapting tomographic algorithms to the Juno-UVS dataset. Tomographic reconstruction will allow estimation of the position and horizontal extent of the auroral regions of interest, as well as their vertical emission structure, which may be used to characterize the energy distribution of the precipitating particles responsible for the features. [less ▲]

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See detailAnomalous OI-989 Å intensity profile: solving an old mystery.
Hubert, Benoît ULg; Gérard, Jean-Claude ULg; Shematovich, Valery I. et al

Poster (2012, December 06)

Sounding rocket measurements conducted in 1988 under high solar activity conditions had revealed that the intensity of the thermospheric OI emission at 989 Å presents an anomalous vertical profile ... [more ▼]

Sounding rocket measurements conducted in 1988 under high solar activity conditions had revealed that the intensity of the thermospheric OI emission at 989 Å presents an anomalous vertical profile. Observation presents an intensity much higher than what can be expected compared with theoretical results including the photochemical sources of excited oxygen and the radiative transfer of the photons of the OI-989 sextuplet especially above the exobase. Attempts were conducted to clarify the discrepancy by including the non-thermal O(3P) population that appears around the exobase and higher, and that can scatter Doppler-shifted photons of the line profile farther from the rest wavelength. All attempts based on detail modeling of the photochemical processes and radiative transfer revealed unable to account for the discrepancy. Recently the FUV and EUV solar flux has been obtained at very high spectral resolution with the SOHO-SUMER instrument, revealing a significant solar oxygen emission at 989 Å, i.e. a source of photons that had never been accounted for before. In this study, we compute the radiative transfer of the OI-989 Å multiplet including the photochemical sources of excited oxygen, the scattering of incident solar photons and the effect of non-thermal atoms. We find a good agreement with the previous sounding rocket observation, solving the old mystery. We also compare the model simulations with the observations of the STP-78 satellite to better determine the relative importance of the various parameters at work in the radiative transfer of the OI-989 Å multiplet. [less ▲]

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See detailHow the debate on the protection of IDPs could inform the debate on the protection of environmental migrations
Gemenne, François ULg; Brücker, Pauline

Conference (2012, December 06)

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See detailExcess Return Forecast Using a Dynamic Asset Class Factor Model
Hübner, Georges ULg; Sougné, Danielle ULg; Wijnandts, Jean-Charles ULg

E-print/Working paper (2012)

We propose a Dynamic Hierarchical Factor Model using Asset classes to predict mutual funds excess returns. We use different forecast combination schemes of bivariate model considering each asset class ... [more ▼]

We propose a Dynamic Hierarchical Factor Model using Asset classes to predict mutual funds excess returns. We use different forecast combination schemes of bivariate model considering each asset class factor in isolation. Primary analysis highlights the importance to account for asset class specific variations together with between classes or common variations. Further refinements of the a priori repartition are however in order. Forecasting performance of the model outperforms the historical mean benchmark both in terms of MSPE and utility based criteria. A forecasting exercise matching more closely real-time conditions must be undertaken to validate these initial results. [less ▲]

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See detailINFLUENCE OF MYELOPEROXIDASE ACTIVITY ON EQUINE POST-THAW SEMEN QUALITY
Ponthier, Jérôme ULg; Franck, Thierry ULg; Parrilla Hernandez, Sonia ULg et al

in Edeas, Marvin (Ed.) Proceedings of the 2nd ISANH World congress on Fertility and Antioxidants (2012, December 06)

This study confirms that active MPO is associated with cellular fraction of the ejaculate, as previously suggested for total MPO concentration in thawed semen (2). However, active MPO concentrations were ... [more ▼]

This study confirms that active MPO is associated with cellular fraction of the ejaculate, as previously suggested for total MPO concentration in thawed semen (2). However, active MPO concentrations were dramatically lower than total MPO concentrations observed in equine semen (3), which could be explained by presence of inactive MPO subunits in semen. MPO activity in sperm-rich pellet can be used as a predictive marker of post-thaw semen quality. Moreover, methods to inhibit MPO should be investigated in semen. [less ▲]

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