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See detailA rigorous phase separation method for testing nonlinear structures
Noël, Jean-Philippe ULg; Renson, Ludovic ULg; Grappasonni, Chiara ULg et al

in Proceedings of ISMA 2014 - International Conference on Noise and Vibration Engineering (2014, September)

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. [less ▲]

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See detailAutomatic biorythms description from actigraphic data
González y Viagas, Miguel ULg; Ly, Julien ULg; Gaggioni, Giulia ULg et al

Poster (2014, September)

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See detailDroit international humanitaire (notes de cours 2014-2015) - Partie VI : La Cour pénale internationale
Deprez, Christophe ULg; Collienne, Fleur ULg

Learning material (2014)

Ce texte co-rédigé par Fleur Collienne et Christophe Deprez dresse un panorama du droit de la Cour pénale internationale. Il constitue la sixième partie d'un ensemble de notes de cours coordonné par Fleur ... [more ▼]

Ce texte co-rédigé par Fleur Collienne et Christophe Deprez dresse un panorama du droit de la Cour pénale internationale. Il constitue la sixième partie d'un ensemble de notes de cours coordonné par Fleur Collienne et Isaline Wittorski, et destiné à servir de support à l'enseignement de droit international humanitaire dispensé à la Faculté de droit, de science politique et de criminologie de l'Université de Liège (année académique 2014-2015). [less ▲]

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See detailImpact de la médiatisation technologique sur la mobilisation des modalités non-verbales dans les références démonstratives.
Defays, Aurore ULg; Jeunejean, Aurélie ULg; Giboin, Alain

in Leclercq, Pierre; Bonnet, Pierre; Dondero, Maria Giulia (Eds.) et al COMMON 14 - Communication multimodale et collaboration instrumentée (2014, September)

L’objectif de ce papier est de comprendre comment la médiatisation technologique et les contraintes d’utilisation d’un outil vont modifier la manière dont les agents vont mobiliser les modalités de ... [more ▼]

L’objectif de ce papier est de comprendre comment la médiatisation technologique et les contraintes d’utilisation d’un outil vont modifier la manière dont les agents vont mobiliser les modalités de communications pour collaborer efficacement. Dans ce travail, nous nous sommes centrés sur les références démonstratives, c’est-à-dire les références verbales qui nécessitent d’être accompagnées de gestes pour que leur interprétation soit complète. Nous avons mené cette recherche dans le domaine de la conception architecturale et avons examiné deux situations de travail collaboratif (une en coprésence et une outillée) dans le but de pouvoir les comparer. Pour chaque situation, nous décrivons comment les architectes s’adaptent aux modalités potentiellement disponibles pour désigner l’objet à quoi ils font référence dans leur discours. Nos résultats montrent que lorsque la modalité gestuelle ne peut être utilisée de manière effective, comme c’est le cas dans la situation outillée, les architectes vont développer des stratégies de compensation. En effet, la modalité graphique va pallier la transmission partielle des gestes en prenant le relais de la fonction de désignation. [less ▲]

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See detailThe freeness problem for products of matrices defined on bounded languages
Charlier, Emilie ULg

in Actes des Journées Montoises d'Informatique Théorique (2014, September)

In this talk, I presented a joint work with Juha Honkala. We study the freeness problem for matrix semigroups. We show that the freeness problem is decidable for upper-triangular 2x2 matrices with ... [more ▼]

In this talk, I presented a joint work with Juha Honkala. We study the freeness problem for matrix semigroups. We show that the freeness problem is decidable for upper-triangular 2x2 matrices with rational entries when the products are restricted to certain bounded languages. We also show that this problem becomes undecidable for large enough matrices. [less ▲]

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See detailAbelian bordered factors and periodicity
Charlier, Emilie ULg; Harju, Tero; Puzynina, Svetlana et al

in Actes des Journées Montoises d'Informatique Théorique (2014, September)

A finite word is bordered if it has a non-empty proper prefix which is equal to its suffix, and unbordered otherwise. Ehrenfeucht and Silberger proved that an infinite word is (purely) periodic if and ... [more ▼]

A finite word is bordered if it has a non-empty proper prefix which is equal to its suffix, and unbordered otherwise. Ehrenfeucht and Silberger proved that an infinite word is (purely) periodic if and only if it contains only finitely many unbordered factors. We are interested in an abelian modification of this fact. Namely, we have the following question: Let w be an infinite word such that all sufficiently long factors are abelian bordered. Is w (abelian) periodic? We also consider a weakly abelian modification of this question, when only the frequencies of letters are taken into account. Besides that, we answer a question of Avgustinovich, Karhumaki and Puzynina concerning abelian central factorization theorem. [less ▲]

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See detailPropriétés physico-chimiques et biologiques des substances humiques en relation avec le développement végétal
Tahiri, Abdelghani ULg; Destain, Jacqueline ULg; Druart, Philippe et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014), 18(3), 436-445

Les substances humiques (SH) sont des composés organiques résultant de la transformation physique, chimique et microbiologique des résidus végétaux et animaux. Elles se retrouvent sous forme de ... [more ▼]

Les substances humiques (SH) sont des composés organiques résultant de la transformation physique, chimique et microbiologique des résidus végétaux et animaux. Elles se retrouvent sous forme de macromolécules carbonées hétérogènes et complexes dans tous les écosystèmes au niveau des sols ainsi que des sédiments, des eaux de surface et des lixiviats de décharges. Elles sont issues de processus d’humification déférents, générant ainsi des molécules variables et complexes composées principalement de carbone, d’hydrogène, d’oxygène, d’azote, de soufre et de groupements fonctionnels (COOH, OH, C=O). Ces substances sont connues pour influencer les propriétés du sol et interagir avec la croissance et le développement des plantes ou avec l’activité des microorganismes. L’influence de la croissance des plantes s’exprime généralement de manière directe via la stimulation des processus biochimiques et métaboliques ou indirecte via l’amélioration de la nutrition minérale. Mais, l’intensité de réponse reste dépendante de différents paramètres tels que l’origine, la nature de la matière organique initiale, les processus de transformation et la concentration des SH ainsi que des conditions expérimentales et des plantes traitées. Les mécanismes par lesquels les SH exercent leurs effets favorables sur les végétaux sont imprécis et généralement pas bien compris. [less ▲]

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See detailLocal Stakeholders’ Perceptions About the Introduction of Performance-Based Financing in Benin: A Case Study in Two Health Districts
Paul, Elisabeth ULg; Sossouhounto, Nadine; Eclou, Dieudonné

in International Journal of Health Policy and Management (2014), 3

Background: Performance-Based Financing (PBF) has been advanced as a solution to contribute to improving the performance of health systems in developing countries. This is the case in Benin. This study ... [more ▼]

Background: Performance-Based Financing (PBF) has been advanced as a solution to contribute to improving the performance of health systems in developing countries. This is the case in Benin. This study aims to analyse how two PBF approaches, piloted in Benin, behave during implementation and what effects they produce, through investigating how local stakeholders perceive the introduction of PBF, how they adapt the different approaches during implementation, and the behavioural interactions induced by PBF. Methods: The research rests on a socio-anthropological approach and qualitative methods. The design is a case study in two health districts selected on purpose. The selection of health facilities was also done on purpose, until we reached saturation of information. Information was collected through observation and semi-directive interviews supported by an interview guide. Data was analysed through contents and discourse analysis. Results: The Ministry of Health (MoH) strongly supports PBF, but it is not well integrated with other ongoing reforms and processes. Field actors welcome PBF but still do not have a sense of ownership about it. The two PBF approaches differ notably as for the organs in charge of verification. Performance premiums are granted according to a limited number of quantitative indicators plus an extensive qualitative checklist. PBF matrices and verification missions come in addition to routine monitoring. Local stakeholders accommodate theoretical approaches. Globally, staff is satisfied with PBF and welcomes additional supervision and training. Health providers reckon that PBF forces them to depart from routine, to be more professional and to respect national norms. A major issue is the perceived unfairness in premium distribution. Even if health staff often refer to financial premiums, actually the latter are probably too weak — and ‘blurred’ — to have a lasting inciting effect. It rather seems that PBF motivates health workers through other elements of its ‘package’, especially formative supervisions. Conclusion: If the global picture is quite positive, several issues could jeopardise the success of PBF. It appears crucial to reduce the perceived unfairness in the system, notably through enhancing all facilities’ capacities to ensure they are in line with national norms, as well as to ensure financial and institutional sustainability of the system. [less ▲]

See detailβ 5 tubulin and 15-protofilament microtubules appeared in supporting cells of the Corti’s organ during development in rodents
Renauld, Justine ULg; Thelen, Nicolas ULg; Johnen, Nicolas et al

Conference (2014, August 31)

A feature of the organ of Corti’s supporting cells is the presence of an abundant cytoskeleton which is mainly composed of microtubules. These supporting cells have also been shown to contain a minor ... [more ▼]

A feature of the organ of Corti’s supporting cells is the presence of an abundant cytoskeleton which is mainly composed of microtubules. These supporting cells have also been shown to contain a minor mammalian tubulin, the β5-tubulin [1], recently related as a biomarker for cancer outcome [2] and cell proliferation [3]. It was shown that a β-tubulin isoform can specified the microtubule architecture, such as the expression of the Moth β2 in the Drosophila testes imposed the 16 protofilaments (16pf) structure on the corresponding subset of Drosophila microtubules, which normally contain 13pf [4]. Moreover, supporting cell microtubules are formed by 15pf instead of the canonical 13, a unique fact among vertebrates [5]. Such a protofilament configuration has been observed in C. elegans’ neurons which are responsible for the mechanosensory sense of touch [6]. It was also shown that these 15pf microtubules were essential to the proper functioning of these mechanosensory neurons [6]. To determine the role of this particular tubulin in the auditory organ and its possible involvement in the formation of the unusual 15pf microtubules of supporting cells, we studied the spatiotemporal localization of β5-tubulin during development in rats from embryonic day 18 until P25 (25th postnatal day). We also analyzed the localization of β5-tubulin mRNA expression in the Corti’s organ. Then we examined the fine structure of microtubules at the electron microscope level. For these experiments, we used an early postnatal stage and a late postnatal stage. Our results showed that β5-tubulin, contrary to other β-tubulins, had a unique distribution in the cochlea. This β-tubulin appeared at a postnatal stage, before the opening of the Corti’s tunnel and being restricted to supporting cells, especially in pillar and Deiters cells,. The same localization of β5-tubulin mRNA was observed by in Situ Hybridization. Electron microscopy indicated further that Pillar and Deiters cells were composed by 15-protofilament microtubules at the late postnatal stage (P25). In conclusion, all these data strongly suggest that there is a relationship between the presence of β5-tubulin and 15-protofilament microtubules in the supporting cells of the auditory organ. Further studies are now needed to elucidate their role. [less ▲]

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See detailAmélioration des moyens d'existence durables. Une voie pour la durabilité des exploitations agricoles familiales de coton au Bénin
Assogba, Claude Gervais; Tossou, C. R.; Lebailly, Philippe ULg et al

Conference (2014, August 30)

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See detailThe effects of a Global Agricultural Policy on the smallholder farmers in ending hunger
Paveliuc-Olariu, Codrin; Burny, Philippe ULg

Conference (2014, August 30)

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See detailL'agriculture de subsistance et de semi-subsistance en Roumanie
Dona, Ion; Burny, Philippe ULg

Conference (2014, August 30)

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See detailAspects économiques de la filière du vermicelle de tolomane au Vietnam
Le Thi Long, Vy; Vu Dinh, Ton; Lebailly, Philippe ULg et al

Conference (2014, August 30)

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See detailProblématique foncière chez les exploitants agricoles de la Province de Kirundo au nord du Burundi
Minani, Bonaventure; Rurema, Déo-Guide; Burny, Philippe ULg et al

Conference (2014, August 30)

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See detailAccelerating Random Forests in Scikit-Learn
Louppe, Gilles ULg

Conference (2014, August 29)

Random Forests are without contest one of the most robust, accurate and versatile tools for solving machine learning tasks. Implementing this algorithm properly and efficiently remains however a ... [more ▼]

Random Forests are without contest one of the most robust, accurate and versatile tools for solving machine learning tasks. Implementing this algorithm properly and efficiently remains however a challenging task involving issues that are easily overlooked if not considered with care. In this talk, we present the Random Forests implementation developed within the Scikit-Learn machine learning library. In particular, we describe the iterative team efforts that led us to gradually improve our codebase and eventually make Scikit-Learn's Random Forests one of the most efficient implementations in the scientific ecosystem, across all libraries and programming languages. Algorithmic and technical optimizations that have made this possible include: - An efficient formulation of the decision tree algorithm, tailored for Random Forests; - Cythonization of the tree induction algorithm; - CPU cache optimizations, through low-level organization of data into contiguous memory blocks; - Efficient multi-threading through GIL-free routines; - A dedicated sorting procedure, taking into account the properties of data; - Shared pre-computations whenever critical. Overall, we believe that lessons learned from this case study extend to a broad range of scientific applications and may be of interest to anybody doing data analysis in Python. [less ▲]

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See detailComputational homogenization of cellular materials with propagation of instabilities through the scales
Nguyen, Van Dung ULg; Noels, Ludovic ULg

Conference (2014, August 29)

The aim of this work is to develop an efficient multi–scale finite element framework to capture the buckling instabilities in cellular materials. As a classical multi–scale computational homogenization ... [more ▼]

The aim of this work is to develop an efficient multi–scale finite element framework to capture the buckling instabilities in cellular materials. As a classical multi–scale computational homogenization scheme looses accuracy with the apparition of the macroscopic localizations resulting from the micro–buckling, the second–order multi–scale computational homogenization scheme1 is considered. This second–order computational framework is herein enhanced 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 interpolation2 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 treatment of high order terms is based on the discontinuous Galerkin (DG) method to weakly impose the C1-continuity3. Finally, as the instability phenomena are considered at both scales of the cellular materials, the path following technique is adopted to solve both the macroscopic and microscopic problems4. The micro–buckling leading to the macroscopic localization and the size effect phenomena can be captured within the proposed framework. In particular it is shown that results are not dependent on the mesh size at the macroscopic scale during the softening response, and that they agree well with the direct numerical simulations. [less ▲]

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See detailLower critical field and SNS-Andreev spectroscopy of 122-arsenides: Evidence of nodeless superconducting gap
Abdel-Hafiez, M.; Pereira, P.J.; Kuzmichev, S.A. et al

in Physical Review. B : Condensed Matter (2014), 90

Using two experimental techniques, we studied single crystals of the 122-FeAs family with almost the same critical temperature, Tc. We investigated the temperature dependence of the lower critical field ... [more ▼]

Using two experimental techniques, we studied single crystals of the 122-FeAs family with almost the same critical temperature, Tc. We investigated the temperature dependence of the lower critical field Hc1(T) of a Ca0.32Na0.68Fe2As2 (Tc ≈ 34 K) single crystal under static magnetic fields H parallel to the c axis. The temperature dependence of the London penetration depth can be described equally well either by a single anisotropic s-wave-like gap or by a two-gap model, while a d-wave approach cannot be used to fit the London penetration depth data. Intrinsic multiple Andreev reflection effect spectroscopy was used to detect bulk gap values in single crystals of the intimate compound Ba0.65K0.35Fe2As2, with the same Tc. We estimated the range of the large gap value L = 6–8 meV (depending on small variation of Tc) and its a k space anisotropy of about 30%, and the small gap Delta ≈ 1.7 ± 0.3 meV. This clearly indicates that the gap structure of our investigated systems more likely corresponds to a nodeless s-wave two gaps. [less ▲]

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See detailLa place de la communication dans la gestion du risque sous l'angle de la responsabilité sociale: le cas des entreprises seveso
Robert, Jocelyne ULg; Frau, Maité; al

in Boudrandi, Stéphane; Delaye, Richard; Peretti, Jean-Marie (Eds.) L'audit social au service du progrès du management et de la bonne gouvernance-Proceedings (2014, August 29)

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