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See detailDerivation and Application of Sensitivities to Assess Transient Voltage Sags caused by Rotor Swings
Weckesser, Tilman; Johannsson, Hjortur; Ostergaard, Jacob et al

in International Journal of Electrical Power & Energy Systems (2015), 72

The paper introduces an approach to investigate voltage sags, which are caused by large generator rotor swings following a transient disturbance. Therefore, the method exploits sensitivities derived from ... [more ▼]

The paper introduces an approach to investigate voltage sags, which are caused by large generator rotor swings following a transient disturbance. Therefore, the method exploits sensitivities derived from the algebraic network equations. These provide information on the impact of a generator on the voltage magnitude at a load bus and the e ffect of load variation on the generator's power injection. It is shown that these sensitivities give valuable information to identify critical generator-load pairs and locations for applying preventive control measures. [less ▲]

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See detailA Parallel Processing Approach to Dynamic Simulations of Combined Transmission and Distribution Systems
Aristidou, Petros ULg; Van Cutsem, Thierry ULg

in International Journal of Electrical Power & Energy Systems (2015), 72

Simulating a power system with both transmission and distribution networks modeled in detail is a huge computational challenge. In this paper, a Schur-complement-based domain decomposition algorithm is ... [more ▼]

Simulating a power system with both transmission and distribution networks modeled in detail is a huge computational challenge. In this paper, a Schur-complement-based domain decomposition algorithm is proposed to provide accurate, detailed dynamic simulations of such systems. The simulation procedure is accelerated with the use of parallel programming techniques, taking advantage of the parallelization opportunities inherent to domain decomposition algorithms. The proposed algorithm is general, portable and scalable on inexpensive, shared-memory, multi-core machines. A large-scale test system is used for its performance evaluation. [less ▲]

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See detailCorps, psychiatrie et philosophie
Englebert, Jérôme ULg

Scientific conference (2015, October 31)

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See detailFlexible multibody system modelling: A geometric local frame approach on SE(3)
Sonneville, Valentin ULg

Scientific conference (2015, October 30)

In order to improve computational costs in the frame of flexible multibody system modelling, we propose a geometrically exact framework relying on a local frame description. Thanks to this framework ... [more ▼]

In order to improve computational costs in the frame of flexible multibody system modelling, we propose a geometrically exact framework relying on a local frame description. Thanks to this framework, geometric non-linearities are strongly reduced for two reasons. Firstly, the equations of motion can be solved without introducing a global parametrization of the motion, which also leads to a naturally singularity-free description of large rotations. Secondly, the equations of motion are expressed in a local frame, both at position and rotation level, leading to intrinsic equations. Accordingly, these equations are insensitive to large amplitude motions, such that the geometric non-linearities are naturally filtered. The mathematical developments are carried out in a Lie group setting which, albeit more abstract than classical treatments, provides generic and powerful well established tools. So far, several elements have been formulated in this framework: rigid body, kinematic joints and a flexible beam finite element. A shell finite element and a super-element are also under development. Some interesting numerical advantages are observed following the reduction of geometric non-linearities, e.g., the iteration matrix depends on relative motion within the elements only and is thus invariant under rigid body motions. [less ▲]

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See detailL'être-au-monde borderline
Englebert, Jérôme ULg

Scientific conference (2015, October 30)

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See detailBenedetto Varchi, gli artisti e l'accademia a Firenze
Geremicca, Antonio ULg

Scientific conference (2015, October 29)

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See detailLes visages d'Alain Baczynsky
Englebert, Jérôme ULg; Séguin, Marion

Scientific conference (2015, October 10)

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See detailEspace, temps et angoisse psychotique : à propos d'un cas magistral
Englebert, Jérôme ULg

Scientific conference (2015, October 10)

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See detailOuverture des travaux
Valenti, Gianluca ULg; Miesse, Hélène ULg

Conference (2015, October 01)

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See detailL’institution de la contre-culture
Saint-Amand, Denis ULg

Conference (2015, October)

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See detailFormer des enseignants soucieux de réduire les inégalités d'apprentissage ou comment tenir le cap entre réponse aux demandes et inertie. Analyse de cas d'un centre de formation d'enseignants en Fédération Wallonie-Bruxelles
Beckers, Jacqueline ULg; Simons, Germain ULg

Conference (2015, October)

Dans cette contribution, nous analyserons l'évolution des enjeux et priorités que s'est progressivement donné le Centre interfacultaire de formation des enseignants (Cifen) de l'Université de Liège depuis ... [more ▼]

Dans cette contribution, nous analyserons l'évolution des enjeux et priorités que s'est progressivement donné le Centre interfacultaire de formation des enseignants (Cifen) de l'Université de Liège depuis sa création officielle en 1995, et nous nous interrogerons sur leur pertinence. Comment prendre la mesure des changements effectivement mis en place, apprécier leur pertinence, réguler leurs effets, éviter l'essoufflement des partenaires du système ? Telles sont quelques unes des questions qui baliseront notre contribution. [less ▲]

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See detailNumerical modeling of the cardiac mechano-electric feedback within a thermo-electro-mechanical framework. Study of its consequences on arrhythmogenesis.
Collet, Arnaud ULg

Doctoral thesis (2015)

This doctoral study characterizes, for simple geometries, the cardiac autonomous electrical activity induced by the mechanical deformations of the myocardium via the mechano-electric feedback within a ... [more ▼]

This doctoral study characterizes, for simple geometries, the cardiac autonomous electrical activity induced by the mechanical deformations of the myocardium via the mechano-electric feedback within a thermo-electro-mechanical framework. The underlying fundamental mechanisms are highlighted and discussed in detail. In a healthy heart, the mechano-electric feedback acts as a regulator able to damp mechanical perturbations undergone by the heart, by appropriately modulating electrical activity shortly after these perturbations. In this way, a new healthy electromechanical situation is recovered. However, under certain conditions, this feedback can be a generator of dramatic cardiac arrhythmias by inducing local electrical depolarizations resulting from abnormal cardiac muscle tissue deformations. These local perturbations can then propagate in the whole heart and, thus, lead to global cardiac dysfunctions. The one- and two-dimensional models developed in this work to study the arrhythmogenic consequences of the mechano-electric feedback within a thermo-electro-mechanical framework account for three couplings: the excitation-contraction coupling, the mechano-electric feedback, and the thermo-electric coupling. The excitation-contraction coupling allows the mechanical contraction of cardiac muscle cells resulting from the electrical excitation of these cells, triggered by a propagating action potential initially generated by the sino-atrial node in a healthy heart. The mechano-electric feedback takes into account the influence of mechanical deformations on the electrical activity, both at the cell and the macroscopic level. The thermo-electric coupling then modulates certain electrical properties due to a temperature change. The excitation-contraction coupling is modeled in a phenomenological way by combining the Aliev-Panfilov model and the Rogers-McCulloch model. The propagation of the electrical excitation through cardiac muscle tissue is modeled by using the monodomain approach. The mechano-electric feedback is taken into account by considering two different contributions, namely the physiological contribution (physiological feedback) and the geometric contribution (geometric feedback). The physiological feedback consists in the onset of stretch-activated currents due to the deformations of the cardiac muscle tissue via specific mechanosensitive channels. Regarding the geometric feedback, it simply reflects that the propagation of the depolarization waves is altered by the deformations of the geometry. The thermo-electric coupling is modeled via a dependence with respect to the temperature which is exponential for the gating kinetics of ion channels, exponential for the kinetics of the active tension development in cardiomyocytes, and linear for the ionic conductances. This study shows that the mechano-electric feedback can be arrhythmogenic under specific conditions. In particular, this work clearly reveals that the size of the domain and the importance of stretch-activated currents are key factors in the behavior of the autonomous electrical activity induced by the mechano-electric feedback. This doctoral study also shows that temperature variations such as those undergone by the heart during therapeutic hypothermia or hyperthermia play a central role in the cardiac electromechanical behavior. Moreover, this work emphasizes the influence of the initial conditions on the electromechanical behavior of cardiac tissue. In the one-dimensional framework, an important result of this work is that the disappearance of the autonomous electrical activity induced by the deformations of the cardiac muscle can be associated with different types of bifurcation phenomena, depending on the values of the parameters. These bifurcations, which correspond in fact to different ways for the AEA to vanish, are emphasized and discussed in detail. [less ▲]

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See detailL'enseignement-apprentissage du néerlandais en Fédération Wallonie-Bruxelles: objectifs, méthodes, résultats
Rasier, Laurent ULg; Hiligsmann, Philippe

Conference (2015, September 30)

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See detailL'énonciation énoncée dans l'image
Dondero, Maria Giulia ULg

in Colas-Blaise, Marion; Tore, Gian Maria; Perrin, Laurent (Eds.) Le sens de l’énonciation (2015)

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See detailGalland épigraphiste et philologue classique
Famerie, Etienne ULg

in Bauden, Frédéric; Waller, Richard (Eds.) Actes du Colloque "Antoine Galland (1646-1715) : orientaliste, antiquaire, numismate, humaniste" (2015, September)

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See detailAn enhanced version of a bone remodelling model based on the continuum damage mechanics theory.
Mengoni, Marlène ULg; Ponthot, Jean-Philippe ULg

in Computer Methods in Biomechanics & Biomedical Engineering (2015), 18(12), 1367-1376

The purpose of this work is to propose an enhancement of Doblaré and García's internal bone remodelling model based on the continuum damage mechanics theory. In their paper, they stated that the evolution ... [more ▼]

The purpose of this work is to propose an enhancement of Doblaré and García's internal bone remodelling model based on the continuum damage mechanics theory. In their paper, they stated that the evolution of the internal variables of the bone microstructure, and its incidence on the modification of the elastic constitutive parameters, may be formulated following the principles of Continuum Damage Mechanics, although no actual damage was considered. The resorption and apposition criteria (similar to the damage criterion) were expressed in terms of a mechanical stimulus. However, the resorption criterion is lacking a dimensional consistency with the remodelling rate. We here propose an enhancement to this resorption criterion, insuring the dimensional consistency while retaining the physical properties of the original remodelling model. We then analyse the change in the resorption criterion hypersurface in the stress space for a 2D analysis. We finally apply the new formulation to analyse the structural evolution of a 2D femur. This analysis gives results consistent with the original model but with a faster and more stable convergence rate. [less ▲]

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See detailThe materiality of Intangible Cultural Heritage: food and social encounters.
Mescoli, Elsa ULg

Conference (2015, September)

Following the patrimonialization process of the Mediterranean diet, some gastronomies found themselves involved within a common framework of food traditions. Some regional practices, indicated as ... [more ▼]

Following the patrimonialization process of the Mediterranean diet, some gastronomies found themselves involved within a common framework of food traditions. Some regional practices, indicated as representative of national food cultures, were chosen to illustrate a shared heritage that historically took a shape around the Mediterranean sea. This heritage, still concretely performed, needed to be stated and preserved against the globalization of food practices. Institutional and political dynamics, occurring on a transnational level, triggered this process, which is nevertheless not detached from the communities involved. Common people played a fundamental role not only in promoting the patrimonialization process itself, but above all in concretely perpetuating some traditions and in spreading them in the contemporary world. In particular, some different cultural groups that found themselves living a common territory and social context thanks to migration, began dialoguing about their own food traditions, starting from some shared elements. As a consequence, some gastronomies interact through people’s practices and define in relation one to the other. This is the case, among others, of Moroccan and Italian cuisine. Throughout a doctoral research conducted within a group of Moroccan women living in the North of Italy, I collected an amount of ethnographic materials showing how social encounters developed through food. The influence of the patrimonialization process on these encounters made people try to find similarities among different traditional practices or to describe some ways of reinterpreting them in reason of the new context. My presentation will focus on these dynamics, thus proving that the Intangible Cultural Heritage is indeed grounded on materiality, that is, in this case, the concrete performance of food practices and their pragmatic effects on relations among humans. [less ▲]

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See detailRorschach et théorie de l’art : Le sublime et le formel
Englebert, Jérôme ULg; Sass, Louis

Conference (2015, August 28)

À côté de l’énorme travail de standardisation réalisé par Exner, l’un des éléments d’avenir qui devrait mobiliser la recherche sur le test de Rorschach concerne la signification psychologique des ... [more ▼]

À côté de l’énorme travail de standardisation réalisé par Exner, l’un des éléments d’avenir qui devrait mobiliser la recherche sur le test de Rorschach concerne la signification psychologique des variables. En effet, le Comprehensive System fournit une solide base empirique offrant une validité et une fidélité de bonne qualité. En revanche, l’étude et la discussion des corrélats psychologiques des différentes cotations et de leurs interprétations demeure un champ de recherche où de nombreuses hypothèses et réflexions sont encore à formuler. Dans ce contexte, nous souhaitons proposer une hypothèse originale qui prendra ses racines dans l’esthétique (Schiller, Burke), la littérature (Stendhal), la philosophie de l’art (Kant) et la philosophie existentielle (Heidegger). Nous proposons d’introduire la notion de « sublime », qui est à différencier du « beau », pour discuter de l’interprétation des Vista (V) et de la Form Dimension (FD). Le sublime suggérerait une submersion des facultés cognitives, voire un état de dépassement, en contraste avec la clarté de la beauté circonscrite dans un espace et totalement sous le contrôle cognitif du sujet. Notre réflexion nous mènera à discuter des liens entre perception et angoisse et de la différence qu’il y a à faire entre cette émotion et la peur. Nous évoquerons pour conclure les dimensions adaptatives des réponses Vista et FD reflétant, selon Rorschach (1921) et Exner (2003) et sans doute à raison, des formes variées du mécanisme d’introspection. [less ▲]

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