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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 ▲]

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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 ▲]

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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 ▲]

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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 ▲]

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See detailLes structures frontalières de renseignement : le modèle français exportable ?
Pirot, Pascal ULg

Conference (2015, February)

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See detailThe variability of primary production in the ocean: from the synoptic to the global scale: The 45th International Liege Colloquium on Ocean Dynamics, Liege, Belgium, May 13-17, 2013
Grégoire, Marilaure ULg; Levy, Marina; Marra, John et al

Book published by Journal of Marine System, Elsevier Science (2015)

The 45th International Liege Colloquium on Ocean Dynamics (http://modb.oce.ulg.ac.be/colloquium/) gathered two hundreds scientists from around the world to discuss new insights related to the evaluation ... [more ▼]

The 45th International Liege Colloquium on Ocean Dynamics (http://modb.oce.ulg.ac.be/colloquium/) gathered two hundreds scientists from around the world to discuss new insights related to the evaluation of primary production at various spatial and temporal scales and in different regions of the world ocean (e.g. the polar and sea-ice region, the coastal and the deep ocean). Over the past two decades, substantial efforts were deployed to evaluate oceanic primary production. These efforts include in situ measurements of uptake rates using isotopic techniques, remote sensing, autonomous instrumentation for bio-optics, carbon or oxygen measurements, and the development of semi-empirical to complex biogeochemical models. The colloquium presented the opportunity to review the current knowledge in the estimation of primary production, and to assess the impact of physical processes on ocean productivity. Particular attention focused on the importance of physical processes at different spatial and temporal scales for controlling the level and variability of primary production and on the development of adequate methodologies to tackle this variability in order to derive large-scale, climate-driven budgets. Refined biogeochemical models considering for instance phytoplankton physiology, the representation of variable elemental stoichiometric ratios, the role of mixotrophy as well as satellite algorithms that are now able to simulate the plankton functional types are good candidates for scaling up. Contributions dealing with the difficult issue of interoperability of in-situ, satellite and modelling estimates of primary production were presented. Details on the terms of reference as well as the thematic session that were organized can be found at http://modb.oce.ulg.ac.be/?page=colloquium&year=2013. [less ▲]

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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 ▲]

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See detailLong-wave infrared digital holography
Georges, Marc ULg

in Picart, Pascal (Ed.) New Techniques in Digital Holography (2015)

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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 ▲]

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See detailL'expérience d'une vie : Sartre, Fanon et nous
Cormann, Grégory ULg

Conference given outside the academic context (2015)

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See detailLinking bees and flowers: mutualistic interaction networks to study ecosystem functioning
Uyttenbroeck, Roel ULg; Monty, Arnaud ULg

Poster (2015, January 30)

In recent years, much attention is going to pollinators, as they are important for the increasing food production while being threatened by agricultural intensification and other environmental drivers ... [more ▼]

In recent years, much attention is going to pollinators, as they are important for the increasing food production while being threatened by agricultural intensification and other environmental drivers. While honeybees (Apis mellifera L.) are generalist according to their flower preferences, wild pollinators’ flower preferences can go from generalist to very specialist. The same goes for plant species, which can be generalist or specialist in the pollinator species they need to get pollinated. The combination of a set of generalist and specialist plant species with a pollinator community consisting of generalists and specialists in a certain habitat, results in an interaction network between pollinators and the visited plant flowers. Studying this mutualistic interaction network is a time-consuming method, but can provide valuable data to calculate indicators of ecosystem functioning. One of the important conclusions that came already out of studies applying this method is that pollination systems are often more generalized than thought based on pollination syndromes. This poster will explore the method of studying mutualistic interaction networks with a focus on the sampling protocol, the indicators that can be derived from the data and their meaning. [less ▲]

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See detailBiochemical methane potential of residues of three banana varieties from Cameroon : fresh and dry peduncles
Awedem wobiwo, Florent; Happi Emaga, Thomas; Fokou, Elie et al

Poster (2015, January 30)

In Cameroon , the ratio of energy cost to standard of living for both electric and fuel energy is higher than in USA and EU. The local energy needs could be met by valorizing local wastes in an ... [more ▼]

In Cameroon , the ratio of energy cost to standard of living for both electric and fuel energy is higher than in USA and EU. The local energy needs could be met by valorizing local wastes in an environmentally and economically sustainable way. Banana and plantain plants produce significant quantities of post-harvest biomass wastes such as bulbs, pseudo stems, leaf sheaths, petioles–midribs, leaf blades, peduncles, rachis and blossoms which can be converted to methane-rich biogas by anaerobic digestion (AD). AD is a natural process of degradation of organic materials. [less ▲]

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See detailFéminiser la voix
Morsomme, Dominique ULg; Remacle, Angélique ULg

Conference (2015, January 29)

Parlée ou chantée, notre voix révèle qui nous sommes. Elle participe à notre identité et véhicule nos émotions (ref. Revis. J). Dans cet exposé, nous présenterons la voix du point de vue du genre. En ... [more ▼]

Parlée ou chantée, notre voix révèle qui nous sommes. Elle participe à notre identité et véhicule nos émotions (ref. Revis. J). Dans cet exposé, nous présenterons la voix du point de vue du genre. En effet, l’Unité Logopédie de la Voix (www.logopedie-voix.be) s’intéresse entre autres à la féminisation vocale chez les personnes transidentitaires, en processus de changement de genre. Ces personnes ne s’identifiant pas au sexe et au genre qui leur ont été attribués à la naissance, elles éprouvent un désir profond de vivre comme une personne du sexe opposé à leur sexe biologique. Lors du processus de transition où ont lieu les transformations nécessaires au changement de genre, la logopédie a pour but d’améliorer la cohérence entre l’apparence de la personne et sa voix. Ainsi, notre recherche se focalise sur ce qui distingue la voix féminine de la voix masculine. Nous visons à développer des stratégies de féminisation vocale, portant sur des paramètres tels que la fréquence fondamentale de la voix (grave ou aigüe), les contours intonatifs, le niveau d’amplitude de certains formants, le débit de parole, son rythme, ou encore le vocabulaire choisi. Féminiser une voix, c’est chercher à comprendre ce qui permet d’en identifier le genre, mais également participer à la construction de l’identité de la personne à part entière. [less ▲]

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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 ▲]

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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 ▲]

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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)

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