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See detailPrecision polymer design by organometallic-mediated radical polymerization
Debuigne, Antoine ULg

Scientific conference (2014, March 13)

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See detailParallel Computing and Localization Techniques for Faster Power System Dynamic Simulations
Aristidou, Petros ULg; Van Cutsem, Thierry ULg

in Proceedings of Cigre 2014 Belgium Conference (2014, March 13)

Dynamic simulation studies are used to analyze the behavior of power systems after a disturbance has occurred. This type of simulation is essential when the system is operating close to its stability ... [more ▼]

Dynamic simulation studies are used to analyze the behavior of power systems after a disturbance has occurred. This type of simulation is essential when the system is operating close to its stability limits or its behavior is dictated by complex control and protection schemes modifying its trajectory. These simulations can be computationally very demanding, especially if performed over a time interval of several minutes. In this paper, new shared- memory parallel computing techniques to increase the performance of large-scale power system dynamic simulations are described. The algorithms presented achieve this by utilizing the parallel processing resources available in modern, inexpensive, multi-core machines. In addition, the localized response of power systems after a disturbance is exploited to further accelerate simulations without decreasing accuracy. The medium-scale model of a real power system and a realistic large-scale test system have been used for the performance evaluation of the proposed methods. [less ▲]

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See detailDetermination of the magnetic penetration depth in a superconducting Pb film
Brisbois, Jérémy ULg; Raes, Bart; Van de Vondel, Joris et al

in Journal of Applied Physics (2014), 115(10), 103906

By means of scanning Hall probe microscopy technique we accurately map the magnetic field pattern produced by Meissner screening currents in a thin superconducting Pb stripe. The obtained field profile ... [more ▼]

By means of scanning Hall probe microscopy technique we accurately map the magnetic field pattern produced by Meissner screening currents in a thin superconducting Pb stripe. The obtained field profile allows us to quantitatively estimate the Pearl length Λ without the need of pre-calibrating the Hall sensor. This fact contrasts with the information acquired through the spatial field dependence of an individual flux quantum where the scanning height and the magnetic penetration depth combine in a single inseparable parameter. The derived London penetration depth λL coincides with the values previously reported for bulk Pb once the kinetic suppression of the order parameter is properly taken into account. [less ▲]

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See detailForcer, cadrer, confisquer le débat. Réflexions sur les médias européens et le discours eurofédéraliste
Geuens, Geoffrey ULg

Conference given outside the academic context (2014)

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See detailWhat is the role of the VLTI in the study of particle acceleration in massive binaries?
De Becker, Michaël ULg

Conference (2014, March 12)

Among massive binaries, a fraction is known to accelerate particles up to relativistic energies. The acceleration process is believed to take place in the wind-wind interaction region, and most of these ... [more ▼]

Among massive binaries, a fraction is known to accelerate particles up to relativistic energies. The acceleration process is believed to take place in the wind-wind interaction region, and most of these systems are identified through the production of synchrotron radiation in the radio domain. Considering the crucial role played by binarity in the physics of particle acceleration, tools such as the VLTI appear to be highly relevant to explore the basic properties of this population of objects. A few recent results and prospects for future studies will be briefly presented. [less ▲]

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See detailBASES NEUROENDOCRINES DU STRESS: du combat ou la fuite, au Syndrome de Cushing.
VALDES SOCIN, Hernan Gonzalo ULg

Scientific conference (2014, March 12)

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See detailAbondance et variabilité des méduses en Baie de Calvi (Corse)
Collignon, Amandine ULg

Doctoral thesis (2014)

L’importance et la variabilité temporelle des méduses calycophores et de la méduse schyphozoaire, Pelagia noctiluca en Baie de Calvi (Corse) ont été étudiées en utilisant une série temporelle planctonique ... [more ▼]

L’importance et la variabilité temporelle des méduses calycophores et de la méduse schyphozoaire, Pelagia noctiluca en Baie de Calvi (Corse) ont été étudiées en utilisant une série temporelle planctonique hebdomadaire de 2003 à 2013. Cette variabilité a été comparée à celles des variables biotiques et abiotiques grâce à la technique du calcul des anomalies saisonnières et interannuelles. La diversité des méduses siphonophores calycophores a été décrite et les critères taxonomiques permettant d’identifier les espèces dominantes (Chelophyes appendiculata, Lensia subtilis, Abylopsis tetragona et Muggiaea atlantica) et de leurs stades de développement ont été précisés. Le cycle de développement de Chelophyes appendiculata a été établi sur base de la variation saisonnière climatique des différents stades moyennée sur les 10 années. Cette espèce est rencontrée toute l’année et présente deux générations, par an. Ce cycle est en phase avec les périodes d’abondance du zooplancton et en particulier des copépodes. Il s’inscrit dans la séquence des événements planctoniques liés à stratification de la colone d’eau. La variation interannuelle se marque par la succession des différentes espèces dont l’abondance augmente sur une période de quatre ans environ. Ainsi au cours des 10 ans, Chelophyes est progressivement remplacé par Lensia. La corrélation entre la moyenne annuelle de l’abondance des eudoxies et celle de la température de surface est très significative et suggère le contrôle de la reproduction par la température. Une relation inverse de l’abondance des stades polygastriques et l’abondance du zooplancton suggère un contrôle de ces méduses sur ce dernier. La distribution spatiale des calycophores a été étudiée au large de la Corse en relation avec les différentes masses d’eau et structures hydrologiques associées au front Liguro-provençal. Les plus fortes abondances sont situées au niveau du plateau continental. Dans 90% des échantillons de surface de fortes abondances de microplastiques étaient associées au zooplancton et aux méduses en particulier. L’étude de la variabilité de la méduse Pelagia noctiluca en Baie de Calvi a confirmé que les invasions obéissent à un cycle pluriannuel indépendamment de la pollution. La distribution en essaims a été étudiée en relation avec les contraintes du milieu. [less ▲]

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See detailWearable respiratory belt for human breathing control
Stoukatch, Serguei ULg; Léonard, Jean; Bellier, Pierre ULg et al

in Conf. Proc. Smart Systems Integration Conf. (SSI2014) (2014, March 12)

We designed and manufactured a working prototype of a wearable respiratory belt. The belt can work as a stand along system or can be embedded into clothes. The system is intended for remote health ... [more ▼]

We designed and manufactured a working prototype of a wearable respiratory belt. The belt can work as a stand along system or can be embedded into clothes. The system is intended for remote health monitoring (particularly to monitor human respiration) such as home healthcare, remote medicine and remote socio-medical assistance as well as to monitor patients. The fully functional prototype proofs the concept that the elongation in the respiratory belt causes by human respiration is accurate enough to measure and to monitor human respiration. [less ▲]

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See detailNotre cerveau reptilien
Scholtes, Félix ULg; Martin, Didier ULg

Scientific conference (2014, March 12)

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See detailOpen-source CAT software: R packages and Concerto
Magis, David ULg

Conference (2014, March 12)

Together with the investigation of new or updated CAT procedures, it is of primary importance to ensure development of appropriate, flexible and useful CAT software. Open-source CAT algorithms have been ... [more ▼]

Together with the investigation of new or updated CAT procedures, it is of primary importance to ensure development of appropriate, flexible and useful CAT software. Open-source CAT algorithms have been recently proposed and are offering very promising tools for future practical CAT implementations, though yet under development. After a brief overview of available (commercial) software, I will present and compare the characteristics of some open-source R packages as CAT solutions: catR (Magis, & Raîche, 2012), catIrt (Nydick, 2013) and MAT (Choi, 2011), as well as the R-based software Firestar (Choi, 2009). A more complete description of catR will be given and (depending on time and computer constraints) a short illustrative session will be proposed. Finally, the web platform Concerto (Kosinski & Rust, 2011) will be shortly introduced. References: Choi, S. W. (2009). Firestar: Computerized adaptive testing simulation program for polytomous item response theory models. Applied Psychological Measurement, 33, 644-645. Choi, S. W. (2011). MAT: Multidimensional Adaptive Testing (MAT). R package version 0.1-3. Kosinski, M., & Rust, J. (2011). The development of Concerto: An open source online adaptive testing platform. Paper presented at the International Association for Computerized Adaptive Testing, Pacific Grove, CA. Magis, D., & Raîche, G. (2012). Random generation of response patterns under computerized adaptive testing with the R package catR. Journal of Statistical Software, 48 (8), 1-31. Nydick, S. W. (2013). catIrt: An R package for simulating IRT-based computerized adaptive tests. R package version 0.4-1. [less ▲]

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See detailOndes de choc et tendinopathies : expérience clinique du CHU de Liège
Kaux, Jean-François ULg

Conference (2014, March 11)

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See detailOn the Identication of Symmetric N-qubit Maximally Entangled States
Baguette, Dorian ULg; Bastin, Thierry ULg; Martin, John ULg

Poster (2014, March 11)

Maximally entangled states can serve as a useful resource in many different contexts. It is therefore important to identify those states. Here we are interested in the identification of maximally ... [more ▼]

Maximally entangled states can serve as a useful resource in many different contexts. It is therefore important to identify those states. Here we are interested in the identification of maximally entangled states in the symmetric subspace of an N-qubit system. By maximally entangled states, we refer to symmetric states characterized by a one qubit reduced density matrix proportional to the identity. These states maximise various entanglement measures [1] such as von Neumann and Meyer-Wallach entropy and are unique up to LU in their SLOCC class [2]. We identify and characterize all maximally entangled symmetric states up to 4 qubits. We provide general conditions for a symmetric state with an arbitrary number of qubits to be maximally entangled and identify families of SLOCC classes which do not contain any maximally entangled states. [1] F. Verstraete, J. Dehaene, B. De Moor, Phys. Rev. A 68, 012103 (2003). [2] G. Gour, N. Wallach, N. J. Phys. 13, 073013 (2011) [less ▲]

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See detailMédias et acteurs économiques en Europe. De la crise du journalisme aux discours de crise
Geuens, Geoffrey ULg

Conference given outside the academic context (2014)

Detailed reference viewed: 29 (12 ULg)
See detailLes pratiques de détournement du jeu vidéo: modding, speedrun, fanfictions et machinimas
Barnabé, Fanny ULg

Scientific conference (2014, March 11)

Cours sur les pratiques de détournement du jeu vidéo par les joueurs: leurs enjeux, leurs statuts, leurs dispositifs formels.

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See detailBringing regenerating tissues to life: the importance of angiogenesis in tissue engineering
Carlier, Aurélie ULg; Van Gastel, Nick; Geris, Liesbet ULg et al

Poster (2014, March 11)

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See detailComputational homogenization of cellular materials capturing micro-buckling, macro-localization and size effects
Nguyen, Van Dung ULg

Doctoral thesis (2014)

The objective of this thesis is to develop an efficient multi-scale finite element framework to capture the macroscopic localization due to the micro-buckling of cell walls and the size effect phenomena ... [more ▼]

The objective of this thesis is to develop an efficient multi-scale finite element framework to capture the macroscopic localization due to the micro-buckling of cell walls and the size effect phenomena arising in structures made of cellular materials. Under the compression loading, the buckling phenomenon (so--called micro--buckling) of the slender components (cell walls, cell faces) of cellular solids can occur. Even if the tangent operator of the material of which the micro--structure is made, is still elliptic, the presence of the micro--buckling can lead to the loss of ellipticity of the resulting homogenized tangent operator. In that case, localization bands are formed and propagate in the macroscopic structure. Moreover, when considering a cellular structure whose dimensions are close to the cell size, the size effect phenomenon cannot be neglected since deformations are characterized by a strain gradient. On the one hand, a classical multi-scale computational homogenization scheme (so-called first-order scheme) looses accuracy with the apparition of the macroscopic localization or the high strain gradient arising in cellular materials because the underlying assumption of the local action principle, in which the stress state on a macroscopic material point depends only on the strain state at that point, is no--longer suitable. On the other hand, the second-order multi-scale computational homogenization scheme proposed by Kouznetsova exhibits a good ability to capture such phenomena. Thus this second--order scheme is improved in this thesis with the following novelties so that it can be used for cellular materials. First, at the microscopic scale, the periodic boundary condition is used because of its efficiency. As the meshes generated from cellular materials exhibit a large void part on the boundaries and are not conforming in general, the classical enforcement based on the matching nodes cannot be applied. A new method based on the polynomial interpolation without the requirement of the matching mesh condition on opposite boundaries of the representative volume element (RVE) is developed. Next, in order to solve the underlying macroscopic Mindlin strain gradient continuum of this second-order scheme by the displacement-based finite element framework, the presence of high order terms (related to the higher stress and strain) leads to many complications in the numerical treatment. Indeed, the resolution requires the continuities not only of the displacement field but also of its first derivatives. This work uses the discontinuous Galerkin (DG) method to weakly impose these continuities. This proposed second--order DG--based FE2 scheme appears to be easily integrated into conventional parallel finite element codes. Finally, the proposed second-order DG-based FE2 scheme is used to model cellular materials. As the instability phenomena are considered at both scales, the path following technique is adopted to solve both the macroscopic and microscopic problems. The micro--buckling leading to the macroscopic localization and the size effect phenomena can be captured within the proposed framework. [less ▲]

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