Last 7 days
Bookmark and Share    
See detailLa démocratie sous expertise. Médias, think tanks et privatisation du débat européen (en préparation, parution début 2015)
Geuens, Geoffrey ULg

Book published by Éditions du Croquant, collection "Savoir / Agir" (2015)

L’ouvrage questionne la genèse des think tanks eurofédéralistes participant à la fabrication et à la légitimation des politiques d’intégration, avant de s’intéresser à ces autres agents sociaux de ... [more ▼]

L’ouvrage questionne la genèse des think tanks eurofédéralistes participant à la fabrication et à la légitimation des politiques d’intégration, avant de s’intéresser à ces autres agents sociaux de production et de diffusion de la pensée européenne que sont notamment les correspondants bruxellois et éditorialistes de quelques grands médias européens. L’ouvrage montre combien le discours journalistique sur l’Europe et le discours de certains « spécialistes » des questions européennes, qui trouve aussi à s’exprimer dans l’espace médiatique, sont la plupart du temps limités à quelques expressions stéréotypées et argumentaires clichés s’expliquant autant par la position occupée dans le champ du pouvoir par les agents qui s’en font les relais que par les dispositions de ces mêmes agents sociaux à l’égard du « projet européen ». [less ▲]

Detailed reference viewed: 92 (36 ULg)
Full Text
See detailExperimental modal analysis of nonlinear structures using broadband data
Noël, Jean-Philippe ULg; Renson, Ludovic ULg; Grappasonni, Chiara ULg et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIII (2015, February)

The objective of the present paper is to develop a rigorous identification methodology of nonlinear normal modes (NNMs) of engineering structures. This is achieved by processing experimental measurements ... [more ▼]

The objective of the present paper is to develop a rigorous identification methodology of nonlinear normal modes (NNMs) of engineering structures. This is achieved by processing experimental measurements collected under broadband forcing. The use of such a type of forcing signal allows to excite multiple NNMs simultaneously and, in turn, to save testing time. A two-step methodology integrating nonlinear system identification and numerical continuation of periodic solutions is proposed for the extraction of the individual NNMs from broadband input and output data. It is demonstrated using a numerical cantilever beam possessing a cubic nonlinearity at its free end. The proposed methodology can be viewed as a nonlinear generalization of the phase separation techniques routinely utilized for experimental modal analysis of linear structures. The paper ends with a comparison between this new nonlinear phase separation technique and a previously-developed nonlinear phase resonance method. [less ▲]

Detailed reference viewed: 32 (6 ULg)
Full Text
See detailExperimental nonlinear identification of an aircraft with bolted connections
De Filippis, Giovanni; Noël, Jean-Philippe ULg; Kerschen, Gaëtan ULg et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIII (2015, February)

Aircraft structures are known to be prone to nonlinear phenomena, especially as they constantly become lighter and hence more flexible. One specific challenge that is regularly encountered is the modeling ... [more ▼]

Aircraft structures are known to be prone to nonlinear phenomena, especially as they constantly become lighter and hence more flexible. One specific challenge that is regularly encountered is the modeling of the mounting interfaces between aircraft subcomponents. Indeed, for large amplitudes of vibration, such interfaces may loosen and, in turn, trigger complex mechanisms such as friction and clearances. In this context, the present work intends to investigate the nonlinear dynamics of the Morane–Saulnier Paris aircraft, accessible at ONERA. This aircraft possesses multiple bolted connections between two external fuel tanks and wing tips. The objective of the paper is specifically to carry out an adequate identification of the numerous nonlinearities affecting the dynamics of this full-scale structure. Nonlinearity detection and the subsequent subspace-based parameter estimation have been performed on experimental data, collected during an on-ground test campaign. Nonlinearity detection is first achieved by the comparison of frequency response functions estimated at low excitation level, with those obtained at high amplitude level, yielding insight towards accurately characterizing the behavior of the bolted connections. Then, a nonlinear subspace identification method is applied to measured data to estimate the linear and nonlinear parameters of the structure and novel strategies and tools that overcome specific arisen problems are developed. [less ▲]

Detailed reference viewed: 58 (1 ULg)
Full Text
Peer Reviewed
See detailNonlinear generalization of Den Hartog׳s equal-peak method
Habib, Giuseppe ULg; Detroux, Thibaut ULg; Viguié, Régis et al

in Mechanical Systems & Signal Processing (2015), 52-53

This study addresses the mitigation of a nonlinear resonance of a mechanical system. In view of the narrow bandwidth of the classical linear tuned vibration absorber, a nonlinear absorber, termed the ... [more ▼]

This study addresses the mitigation of a nonlinear resonance of a mechanical system. In view of the narrow bandwidth of the classical linear tuned vibration absorber, a nonlinear absorber, termed the nonlinear tuned vibration absorber (NLTVA), is introduced in this paper. An unconventional aspect of the NLTVA is that the mathematical form of its restoring force is tailored according to the nonlinear restoring force of the primary system. The NLTVA parameters are then determined using a nonlinear generalization of Den Hartog׳s equal-peak method. The mitigation of the resonant vibrations of a Duffing oscillator is considered to illustrate the proposed developments. [less ▲]

Detailed reference viewed: 31 (4 ULg)
Full Text
See detailBridging the gap between Nonlinear Normal Modes and Modal Derivatives
Sombroek, Cees; Renson, Ludovic ULg; Tiso, Paolo et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIII (2015, February)

Nonlinear Normal Modes (NNMs) have a clear conceptual relation to the classical linear normal modes (LNMs), yet they offer a solid theoretical framework for interpreting a wide class of non-linear ... [more ▼]

Nonlinear Normal Modes (NNMs) have a clear conceptual relation to the classical linear normal modes (LNMs), yet they offer a solid theoretical framework for interpreting a wide class of non-linear dynamical phenomena with no linear counterpart. The main difficulty associated with NNMs is that their calculation for large-scale models is expensive, particularly for distributed nonlinearities. Repeated direct time integrations need to be carried out together with extensive sensitivity analysis to reproduce the frequency-energy dependence of the modes of interest. In the present paper, NNMs are computed from a reduced model obtained using a quadratic transformation comprising LNMs and Modal Derivatives (MDs). Previous studies have shown that MDs can capture the essential dynamics of geometrically nonlinear structures and can greatly reduce the computational cost of time integration. A direct comparison with the NNMs computed from another standard reduction technique highlights the capability of the proposed reduction method to capture the essential nonlinear phenomena. The methodology is demonstrated using simple examples with 2 and 4 degrees of freedom. [less ▲]

Detailed reference viewed: 8 (1 ULg)
Full Text
Peer Reviewed
See detailOn modular decompositions of system signatures
Marichal, Jean-Luc; Mathonet, Pierre ULg

in Journal of Multivariate Analysis (2015), 134

Considering a semicoherent system made up of $n$ components having i.i.d. continuous lifetimes, Samaniego defined its structural signature as the $n$-tuple whose $k$-th coordinate is the probability that ... [more ▼]

Considering a semicoherent system made up of $n$ components having i.i.d. continuous lifetimes, Samaniego defined its structural signature as the $n$-tuple whose $k$-th coordinate is the probability that the $k$-th component failure causes the system to fail. This $n$-tuple, which depends only on the structure of the system and not on the distribution of the component lifetimes, is a very useful tool in the theoretical analysis of coherent systems. It was shown in two independent recent papers how the structural signature of a system partitioned into two disjoint modules can be computed from the signatures of these modules. In this work we consider the general case of a system partitioned into an arbitrary number of disjoint modules organized in an arbitrary way and we provide a general formula for the signature of the system in terms of the signatures of the modules. The concept of signature was recently extended to the general case of semicoherent systems whose components may have dependent lifetimes. The same definition for the $n$-tuple gives rise to the probability signature, which may depend on both the structure of the system and the probability distribution of the component lifetimes. In this general setting, we show how under a natural condition on the distribution of the lifetimes, the probability signature of the system can be expressed in terms of the probability signatures of the modules. We finally discuss a few situations where this condition holds in the non-i.i.d. and nonexchangeable cases and provide some applications of the main results. [less ▲]

Detailed reference viewed: 13 (0 ULg)
Full Text
See detailExperimental demonstration of a 3D-printed nonlinear tuned vibration absorber
Grappasonni, Chiara ULg; Habib, Giuseppe ULg; Detroux, Thibaut ULg et al

in Proceedings of the International Modal Analysis Conference (IMAC) XXXIII (2015, February)

Engineering structures are designed to be lighter and more flexible, hence reducing the extent of application of linear dynamic models. Concurrently, vibration mitigation is required for enhancing the ... [more ▼]

Engineering structures are designed to be lighter and more flexible, hence reducing the extent of application of linear dynamic models. Concurrently, vibration mitigation is required for enhancing the performance, comfort or safety in real-life applications. Passive linear vibration absorbers are purpose-built, often designed using Den Hartog's equal-peak strategy. However, nonlinear systems are known to exhibit frequency-energy-dependent oscillations which linear absorbers cannot effectively damp out. In this context, the paper introduces a new nonlinear tuned vibration absorber (NLTVA) whose nonlinear functional form is tailored according to the frequency-energy dependence of the nonlinear primary structure. The NLTVA design aims at ensuring equal peaks in the nonlinear receptance function for an as large as possible range of forcing amplitudes, hence generalizing Den Hartog's method to nonlinear systems. Our focus in this study is on experimental demonstration of the NLTVA performance using a primary structure consisting of a cantilever beam with a geometrically nonlinear component at its free end. The absorber is implemented using a doubly-clamped beam fabricated thanks to 3D printing. The NLTVA performance is also compared with that of the classical linear tuned vibration absorber. [less ▲]

Detailed reference viewed: 37 (4 ULg)
Peer Reviewed
See detailCore-shell AgSiO2-Protoporphyrin IX nanoparticle: Effect of the Ag core on reactive oxygen species generation
Lismont, Marjorie ULg; Pàez Martinez, Carlos ULg; Dreesen, Laurent ULg

in SPIE proceeding - Colloidal Nanoparticles for Biomedical Applications X (2015, February)

Photodynamic therapy (PDT) for cancer is based on the use of a light sensitive molecule to produce, under specific irradiation, toxic reactive oxygen species (ROS). A way to improve the therapy efficiency ... [more ▼]

Photodynamic therapy (PDT) for cancer is based on the use of a light sensitive molecule to produce, under specific irradiation, toxic reactive oxygen species (ROS). A way to improve the therapy efficiency is to increase the amount of produced ROS near cancer cells. This aim can be achieved by using a metal enhanced process arising when an optically active molecule is located near a metallic nanoparticle (NP). Here, the coupling effect between silver (Ag) NPs and protoporphyrin IX (PpIX) molecules, a clinically approved photosensitizer, is studied compared first, to PpIX fluorescence yield and second, to ROS production efficiency. By applying a modified Stöber process, PpIX was encapsulated into a silica (SiO2) shell, surrounding a 60 nm sized Ag core. We showed that, compared to SiO2-PpIX NPs, Ag coated SiO2-PpIX NPs dramatically decreased PpIX fluorescence together with singlet oxygen production efficiency. However, after incubation time in the dark, the amount of superoxide anions generated by the Ag doped sample was higher than the control sample one. [less ▲]

Detailed reference viewed: 10 (2 ULg)
Full Text
Peer Reviewed
See detailLe dosage de la vitamine D: considérations pré-analytiques et analytiques
LE GOFF, Caroline ULg; Souberbielle, Jean-Claude; Delvin, Edgard et al

in Annales de Biologie Clinique (2015), 73(1), 79-92

The constantly increasing requests for the measurement of serum 25-hydroxyvitamin D over the last years has led reagent manufacturers to market different automated and semi-automated methods, that being ... [more ▼]

The constantly increasing requests for the measurement of serum 25-hydroxyvitamin D over the last years has led reagent manufacturers to market different automated and semi-automated methods, that being unfortunately not fully harmonized, yield different results. Liquid chromatography coupled to tandem mass spectrometry has more recently been introduced. This approach allows the distinction between the two forms of 25-hydroxyvitamin D and to measure other metabolites. This approach also requires harmonization to curtail the differences between the different analytical methods. To meet this requirement, the American national institutes of health (NIH), the CDC (Center for disease control and prevention) in Atlanta, the NIST (National institute of standards and technology) and the vitamin D Reference laboratory of Ghent University have pooled their expertise to develop a standardization program. This article reviews the main elements and the difficulties of the automated and semi-automated methods for 25-hydroxyvitamin D, from sample preparation to the analytical phase, as well as those related to mass spectrometry. It also addresses the issues related to the clinical decision thresholds and the possibility of measurements in different biological liquids. [less ▲]

Detailed reference viewed: 8 (2 ULg)
Full Text
See detailGeräusch, Gerücht, Gerede. Formen und Funktionen der Fama in Erzähltexten Theodor Storms und Arthur Schnitzlers
Leyh, Valérie ULg

Doctoral thesis (2015)

Dans sa représentation allégorique de Fama, le poète latin Ovide évoque trois phénomènes précis : son aspect acoustique (le bruit), sa forme discursive (les racontars) et son lien au récit (la rumeur ... [more ▼]

Dans sa représentation allégorique de Fama, le poète latin Ovide évoque trois phénomènes précis : son aspect acoustique (le bruit), sa forme discursive (les racontars) et son lien au récit (la rumeur). Alors que ces phénomènes ont très souvent fait l'objet d’études sociologiques et anthropologiques, il s’agit ici de les étudier en tant qu’objets d’un processus d’esthétisation. La thèse vise ainsi à décrire une « poétique de Fama » par l’analyse d’un choix de textes narratifs des auteurs germanophones Theodor Storm (1817 – 1888) et Arthur Schnitzler (1862 – 1931). En effet, les recherches récentes sur l’anticipation de la psychologie et sur les questions de perception chez Storm soulignent l’importance de stratégies narratives au caractère indirect, voilé et mettant à mal la plausibilité ; elles révèlent la nécessité d’étudier la rumeur comme élément thématique mais aussi structurel et formel. Les nombreux aspects de Fama intimement liés aux processus narratifs (polyphonie, psychologisation, contournement de la censure) permettent ensuite de confronter les textes de Storm à ceux de Schnitzler et d'y préciser les interactions subtiles entre bruit, racontars et rumeur. Dans ce traitement littéraire de Fama, il s’avère en outre primordial de mettre en lumière ses multiples fonctions selon les différents niveaux textuels (personnages, narrateur, auteur) et d’accorder une place au lecteur qui, dans une approche interactionnelle du récit, prend souvent part à la communication rumorale. Ces distinctions permettent de mettre en exergue la dimension poétologique de Fama dans ses différentes formes : si celle-ci participe à la création d’effets paradoxaux et de structures équivoques au sein des textes, c’est parce que la rumeur, en tant que forme de narration à caractère ambivalent et protéiforme, est fortement autoréflexive. L’instabilité et la contingence, l’indétermination de seuils et de frontières sont autant de traits qui caractérisent non seulement la rumeur et les racontars mais aussi les textes d’une époque marquée par de grandes mutations et par la mise en doute de valeurs et données acquises jusque-là. [less ▲]

Detailed reference viewed: 18 (3 ULg)
Peer Reviewed
See detailLes structures frontalières de renseignement : le modèle français exportable ?
Pirot, Pascal ULg

Conference (2015, February)

Detailed reference viewed: 6 (1 ULg)
Peer Reviewed
See detailDépasser la situation : de la situation-limite à la personnalité borderline. Généalogie, critique et clinique d’un concept sartrien
Cormann, Grégory ULg; Englebert, Jérôme ULg

Conference (2015, January 31)

Nous souhaitons interroger ici le concept sartrien de situation à partir d’une double approche historique et psychopathologique qui semble en diagnostiquer la disparition tout aussi bien conceptuelle ... [more ▼]

Nous souhaitons interroger ici le concept sartrien de situation à partir d’une double approche historique et psychopathologique qui semble en diagnostiquer la disparition tout aussi bien conceptuelle qu’existentielle : la notion de situation, organisatrice de l’ontologie phénoménologique de Sartre et pivot de son engagement, semble s’être aujourd’hui désintégrée en tant que concept (voir ses usages pseudo-conceptuels dans les domaines de la pédagogie et du management), alors que ce qu’on appelle la « condition postmoderne », telle qu’elle s’exprime dans de nouvelles symptomatologies psychopathologiques, rend apparemment caduque, face à la fragmentation des repères de l’existence, l’exigence de penser en/la situation. Nous procèderons en trois temps. Nous ferons d’abord la généalogie du concept, dont l’application à la psyché humaine et à la représentation théâtrale de celle-ci remonte, selon Leo Spitzer, à la fin du 17ème siècle. Dans cette première section, nous insisterons en particulier sur le rapport que l’élaboration du concept de situation entretient, au début du 20ème siècle, avec l’émergence de la psychopathologie notamment chez Jaspers (« situation-limite ») et chez Minkowski (nous rappellerons à cet égard le rôle de Gabriel Marcel dans le champ philosophique français de l’entre-deux-guerres). Nous serons également attentifs à la critique méthodologique que le concept de situation permet d’adresser à la métapsychologie freudienne. Sur cette base, nous reprendrons ensuite les principales étapes chez Sartre de la prise en considération de l’homme en situation et des possibilités de dépassement de cette situation. Nous envisagerons successivement l’Esquisse d’une théorie des émotions, « Questions de méthode » et L’Idiot de la famille. Il conviendra certes de rappeler comment l’existentialisme, comme le situationnisme à sa façon, a cherché, dans le sillage du marxisme, à réaliser la philosophie et du coup à transformer le concept en vécu. Mais nous montrerons aussi, à rebours, comment l’œuvre sartrienne, confrontée aux exigences conjointes du marxisme et de la psychanalyse (cf. l’analyse des pressions familiales dans le Flaubert), a dû dépasser le cadre de la magie émotionnelle au sein duquel la notion de situation s’était d’abord élaborée. Au-delà de la « situation sartrienne » – et peut-être en la prolongeant –, la critique de Deleuze des dispositifs nous servira enfin, dans un troisième temps, de point de bascule vers la condition postmoderne et la fragmentation de la situation en tant que repère d’existence. Le sujet borderline – véritable éclat de la postmodernité – nous permettra ainsi de conclure en reprenant le propos psychopathologique maturé par l’évolution conceptuelle de la situation. Nous caractériserons l’existence borderline par une fragmentation du soi corrélée à une explosion, voire à un morcellement, des espaces de vie qui répondent à la nécessité ontologique d’une « ubiquité instantanée » dénuée de présence corporelle (comme le permettent les espaces virtuels « connectés »). [less ▲]

Detailed reference viewed: 41 (6 ULg)
See detailL'expérience d'une vie : Sartre, Fanon et nous
Cormann, Grégory ULg

Conference given outside the academic context (2015)

Detailed reference viewed: 8 (1 ULg)
Full Text
Peer Reviewed
See detailUsing shear strain localisation to model the fracturing around gallery in unsaturated Callovo-Oxfordian claystone
Pardoen, Benoît ULg; Levasseur, Séverine ULg; Collin, Frédéric ULg

in Chau, Kam Tim; Zhao, Jidong (Eds.) Bifurcation and Degradation of Geomaterials in the New Millennium (2015, January 28)

Galleries drilling leads to damage propagation, fracturing and properties modifications in the surrounding medium. The prediction of the damaged zone behaviour is an important matter and needs to be ... [more ▼]

Galleries drilling leads to damage propagation, fracturing and properties modifications in the surrounding medium. The prediction of the damaged zone behaviour is an important matter and needs to be properly assessed. To do so the fractures can be modelled using shear strain localisation. The coupled local second gradient model is used under unsaturated conditions to correctly model the strain localisation behaviour. The permeability evolution and the rock desaturation due to air ventilation in galleries are considered. Finally, a hydro-mechanical modelling of a gallery excavation in Callovo-Oxfordian claystone is performed leading to a fairly good representation of the damaged zone. [less ▲]

Detailed reference viewed: 51 (16 ULg)
Peer Reviewed
See detailLe testing adaptatif informatisé : une brève introduction
Magis, David ULg

Conference (2015, January 27)

L’objet de cet exposé est de présenter les grands principes et concepts du testing adaptatif informatisé (TAI). Les éléments abordés sont : le TAI face au test fixe (papier-crayon), les principes généraux ... [more ▼]

L’objet de cet exposé est de présenter les grands principes et concepts du testing adaptatif informatisé (TAI). Les éléments abordés sont : le TAI face au test fixe (papier-crayon), les principes généraux du TAI (banque d’items, estimation provisoire et finale de la compétence, sélection des items à administrer, règles d’arrêt), les principes spécifiques au TAI (contrôle de l’exposition des items, équilibrage du contenu des tests). L’exposé se veut didactique et général afin de dessiner les contours du TAI. Il se termine par un état de l’art sur les recherches actuelles sur le TAI. [less ▲]

Detailed reference viewed: 18 (1 ULg)
Full Text
Peer Reviewed
See detailAPPUI ANALYTIQUE A LA LUTTE CONTRE LES MEDICAMENTS DE QUALITE INFERIEURE
Mbinze Kindenge, Jérémie; Hubert, Philippe ULg; Marini Djang'Eing'A, Roland ULg

Conference (2015, January 27)

Detailed reference viewed: 15 (1 ULg)
Full Text
See detailLe jeu vidéo comme objet de recherche
Barnabé, Fanny ULg

Scientific conference (2015, January 26)

Présentation du jeu vidéo en tant qu'objet de recherche et de l'histoire des game studies, avec un accent mis sur la question de la narration et sur le rôle qu'elle a joué dans la structuration du champ.

Detailed reference viewed: 7 (0 ULg)
Full Text
See detailSystème européen des comptes (SEC) et finances publiques locales
Piron, Damien ULg

Conference given outside the academic context (2015)

Detailed reference viewed: 14 (1 ULg)