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See detailVelocity and turbulence measurements for assessing the stability of riverbeds: a comparison between UVP and ADVP
Duma, Diana ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in 11th International Conference on Hydroscience & Engineering - "Hydro-Engineering for Environmental Challenges" (2014, October)

Maintaining the overall stability of active riverbeds requires a deep understanding of the complex interactions between turbulent flow forces and forces stabilizing the riverbed. Standard approaches do ... [more ▼]

Maintaining the overall stability of active riverbeds requires a deep understanding of the complex interactions between turbulent flow forces and forces stabilizing the riverbed. Standard approaches do not properly take into account the turbulence fluctuations in non-uniform flows, while these are of primary importance in the mechanisms determining the stability of stones. In a new approach, the flow forces are quantified by means of parameters combining explicitly the velocity and turbulence distributions over a certain water depth above the riverbed. In this paper, as an onset for using these newly developed bed stability parameters, we report on new experimental measurements of velocity and turbulent kinetic energy based on acoustic methods, whereas all previous uses at the new bed stability parameters relied on Laser PIV Techniques. For quasi-uniform and non-uniform flow conditions, velocity measurements were conducted with two complementary devices: an ultrasonic velocimeter probe (UVP) and an acoustic Doppler velocimeter profiler (ADVP). The results are compared and discussed in detail. A general consistency between the two types of measurements is obtained, while some discrepancies are highlighted close to the bed and tentative explanations are given. [less ▲]

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See detailLes valeurs et les valorisations des images
Dondero, Maria Giulia ULg

in Biglari, Amir (Ed.) Les valeurs. Aux fondements de la sémiotique (2014)

Cet article vise à explorer la manière dont la sémiotique greimassienne a traité la question des valeurs dans le cadre de l’image, notamment photographique et artistique. Après une relecture critique de ... [more ▼]

Cet article vise à explorer la manière dont la sémiotique greimassienne a traité la question des valeurs dans le cadre de l’image, notamment photographique et artistique. Après une relecture critique de l’ouvrage de Jean-Marie Floch, Les formes de l’empreinte, et de la distinction entre valeurs dans l’image et valorisations des images, ce travail se consacre à l’exposition de nouvelles propositions de la sémiotique des pratiques de Jacques Fontanille en essayant de les lier à des réflexions sur les objets et les pratiques de la photographie artistique (l’utilisation des séries, de l’original, des différents tirages, etc.). Si l’attention est portée surtout sur la photo artistique, ce texte envisage également une comparaison avec les pratiques de l’original et de l’authenticité dans la photo de guerre, la photo de famille et la photo-image pieuse. L’objectif majeur de ce travail est d’étudier les diverses pratiques de valorisation des images photographiques afin de faire éclater la notion ontologique de trace photographique. [less ▲]

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See detailAzione, testualizzazione, notazione
Dondero, Maria Giulia ULg

in Espressione e contenuto. Rivista on-line dell'AISS Associazione Italiana di Studi Semiotici (2014, October)

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See detailLes porcheries : réservoirs des culicoïdes (Diptera: Ceratopogonidae), vecteurs des virus de la Maladie de la Langue bleue et de Schmallenberg ?
Zimmer, Jean-Yves ULg; Saegerman, Claude; Martinelle, Ludovic et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2014)

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See detailHighly dispersed iron xerogel catalysts for p-nitrophenol degradation by photo-Fenton effects
Mahy, Julien ULg; Tasseroul, Ludivine ULg; Zubiaur, Anthony ULg et al

in Microporous & Mesoporous Materials (2014), 197

Several iron xerogel catalysts were synthesized by hydrolysis and condensation of tetraethoxysilane (TEOS) and 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) which is able to form a chelate with iron ... [more ▼]

Several iron xerogel catalysts were synthesized by hydrolysis and condensation of tetraethoxysilane (TEOS) and 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS) which is able to form a chelate with iron ions. The EDAS/TEOS ratio strongly influences the texture of xerogel catalysts. The specific surface area and the micro- and mesoporous volume increase with this ratio. It seems that EDAS plays a nucleating agent role for silica particles and allows to anchor Fe-based moieties inside the silica network. Iron oxide nanoparticles of diameter 1-1.5 nm and Fe3+ ions result, encapsulated in silica particles with sizes of about 10-30 nm in diameter. The iron species was determined by Mössbauer spectroscopy and magnetometry measurements and only Fe3+ species were observed in xerogel catalysts. The Fenton and photo-Fenton effect of these catalysts were evaluated on the degradation of p-nitrophenol in aqueous media under different conditions. Results show that in the presence of H2O2, iron xerogel catalysts present a photo-Fenton effect, reaching 99 % of degradation after 24 h. [less ▲]

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See detailUnderstanding Random Forests: From Theory to Practice
Louppe, Gilles ULg

Doctoral thesis (2014)

Data analysis and machine learning have become an integrative part of the modern scientific methodology, offering automated procedures for the prediction of a phenomenon based on past observations ... [more ▼]

Data analysis and machine learning have become an integrative part of the modern scientific methodology, offering automated procedures for the prediction of a phenomenon based on past observations, unraveling underlying patterns in data and providing insights about the problem. Yet, caution should avoid using machine learning as a black-box tool, but rather consider it as a methodology, with a rational thought process that is entirely dependent on the problem under study. In particular, the use of algorithms should ideally require a reasonable understanding of their mechanisms, properties and limitations, in order to better apprehend and interpret their results. Accordingly, the goal of this thesis is to provide an in-depth analysis of random forests, consistently calling into question each and every part of the algorithm, in order to shed new light on its learning capabilities, inner workings and interpretability. The first part of this work studies the induction of decision trees and the construction of ensembles of randomized trees, motivating their design and purpose whenever possible. Our contributions follow with an original complexity analysis of random forests, showing their good computational performance and scalability, along with an in-depth discussion of their implementation details, as contributed within Scikit-Learn. In the second part of this work, we analyze and discuss the interpretability of random forests in the eyes of variable importance measures. The core of our contributions rests in the theoretical characterization of the Mean Decrease of Impurity variable importance measure, from which we prove and derive some of its properties in the case of multiway totally randomized trees and in asymptotic conditions. In consequence of this work, our analysis demonstrates that variable importances as computed from non-totally randomized trees (e.g., standard Random Forest) suffer from a combination of defects, due to masking effects, misestimations of node impurity or due to the binary structure of decision trees. Finally, the last part of this dissertation addresses limitations of random forests in the context of large datasets. Through extensive experiments, we show that subsampling both samples and features simultaneously provides on par performance while lowering at the same time the memory requirements. Overall this paradigm highlights an intriguing practical fact: there is often no need to build single models over immensely large datasets. Good performance can often be achieved by building models on (very) small random parts of the data and then combining them all in an ensemble, thereby avoiding all practical burdens of making large data fit into memory. [less ▲]

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See detailPrevenção Quaternária e limites em medicina
Jamoulle, Marc ULg; Gomes, Luis

in Revista Brasileira de Medicina de Família e Comunidade (2014), 9(31),

O conceito de Prevenção Quaternária, um questionamento sobre a base da ação médica, nasceu na articulação da relação médico-paciente. Refere-se a toda a atividade médica, sendo uma importante ferramenta ... [more ▼]

O conceito de Prevenção Quaternária, um questionamento sobre a base da ação médica, nasceu na articulação da relação médico-paciente. Refere-se a toda a atividade médica, sendo uma importante ferramenta para a medicina de família. É uma interrogação ética sobre os excessos da demasiada e demasiadamente pouca medicina e fornece algumas respostas. [less ▲]

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See detailInter-professional cooperation between family, occupational and social insurance physicians in managing long-term sickness absence
Mairiaux, Philippe ULg; Vanmeerbeek, Marc ULg; Schippers, Nathalie ULg et al

Conference (2014, September 30)

Background In the Belgian health system, sickness absence (SA) management implies complementary roles for general practitioners (GPs), social insurance physicians (SIPs) and occupational physicians (OPs ... [more ▼]

Background In the Belgian health system, sickness absence (SA) management implies complementary roles for general practitioners (GPs), social insurance physicians (SIPs) and occupational physicians (OPs): GPs deliver sick notes and treatment, SIPs control SA benefits and OPs strive to adapt work environments to workers’ remaining capacities. In practice however, there is little cooperation between the three physicians. In 2009, the Ministry of Employment commissioned a study to identify GP-OP-SIP cooperation channels in order to prevent long-term work disability. Methods The study involved two phases. 1) Researchers from the three groups agreed on 15 proposals to enhance cooperation: to establish a formal contact between GP, SIP and OP for patients with > 3 months SA (n=3) ; SIP decision to end SA benefit to be forwarded to the GP (n=2) ; work-related information to be provided by the OP to GP and/or SIP (n=4); website giving contact data of GPs, SIPs, and OPs (n=2) ; initial and continuous education focusing on inter-physician cooperation (n=3); electronic data exchange when dealing with long-term SA (n=1). 2) A Delphi study was conducted in 2012 to validate these proposals: 61 experts representing professional groups of physicians (GP, SIP, OP), patients, government, employers and labor unions were asked to participate. A 18-items questionnaire (the 15 proposals and 3 open questions) was used in a 2-round Delphi study. Proposals were accepted if 80% of experts agreed. For drafting the final proposals, the research team relied on a multidisciplinary expert group. Results Participation rate was 77% (47/61 experts) in round 1 and 7 out of the 15 proposals were accepted. During round 2, participation rate was 94% (44/47); 2 of the remaining proposals reached agreement level. Public authorities were thus advised to invest in a) promotion of pre-return to work visit with the OP for sick-listed patients; b) a website with OPs contact data; c) joint guidelines for return to work guidance; d) joint training of the 3 physician groups; 5) methods ensuring safe electronic information exchange. Conclusions The need for inter-physician cooperation in disability management may exceed individual goodwill and should best be organised by public authorities. The current study may be a first step in this process. [less ▲]

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See detailTable ronde autour de "Psychopathologie de l'homme en situation"
Englebert, Jérôme ULg

Scientific conference (2014, September 29)

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See detailDysphasie : Réflexions autour de la définition et des critères diagnostiques
Leclercq, Anne-Lise ULg; Maillart, Christelle ULg

in Les entretiens de Bichat : les entretiens d'orthophonie 2014 : Les "dys", état de l'art et orientations cliniques (2014, September 27)

Specific language impairment refers to a non-homogeneous group: linguistic and non-linguistic abilities differ from one child to another. Increasing knowledge in this field has led to clarify both the ... [more ▼]

Specific language impairment refers to a non-homogeneous group: linguistic and non-linguistic abilities differ from one child to another. Increasing knowledge in this field has led to clarify both the definition and the diagnostic criteria in order to facilitate its diagnosis. However, the clinical complexity of this trouble questions the relevance of these diagnostic criteria. The present article intends to think about the clinical diagnostic of specific language impairment in order to allow informed decision making during its assessment and therapy. [less ▲]

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See detailFORMATION: Atelier clinique en prise en charge neuropsychologique
Adam, Stéphane ULg

Diverse speeche and writing (2014)

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See detail9th Congress of the International Society of NeuroImmunoModulation (ISNIM)
Geenen, Vincent ULg

Scientific conference (2014, September 25)

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See detailDevant le forum de la perception interne. Sur les objets d’ordre supérieur III
Zincq, Aurélien ULg

Conference (2014, September 25)

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See detailObjets réels et objets idéaux. Sur les objets d’ordre supérieur II
Zincq, Aurélien ULg

Conference (2014, September 23)

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See detailVers une vision plus positive de la maladie d'Alzheimer: Enjeux cliniques et éthique
Adam, Stéphane ULg

Conference given outside the academic context (2014)

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See detailComplexions et relations. Sur les objets d’ordre supérieur I
Zincq, Aurélien ULg

Conference (2014, September 22)

Detailed reference viewed: 13 (1 ULg)