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See detailNIMEFI: Gene Regulatory Network Inference using Multiple Ensemble Feature Importance Algorithms
Ruyssinck, Joeri; Huynh-Thu, Vân Anh ULg; Geurts, Pierre ULg et al

in PLoS ONE (2014)

One of the long-standing open challenges in computational systems biology is the topology inference of gene regulatory networks from high-throughput omics data. Recently, two community-wide efforts ... [more ▼]

One of the long-standing open challenges in computational systems biology is the topology inference of gene regulatory networks from high-throughput omics data. Recently, two community-wide efforts, DREAM4 and DREAM5, have been established to benchmark network inference techniques using gene expression measurements. In these challenges the overall top performer was the GENIE3 algorithm. This method decomposes the network inference task into separate regression problems for each gene in the network in which the expression values of a particular target gene are predicted using all other genes as possible predictors. Next, using tree-based ensemble methods, an importance measure for each predictor gene is calculated with respect to the target gene and a high feature importance is considered as putative evidence of a regulatory link existing between both genes. The contribution of this work is twofold. First, we generalize the regression decomposition strategy of GENIE3 to other feature importance methods. We compare the performance of support vector regression, the elastic net, random forest regression, symbolic regression and their ensemble variants in this setting to the original GENIE3 algorithm. To create the ensemble variants, we propose a subsampling approach which allows us to cast any feature selection algorithm that produces a feature ranking into an ensemble feature importance algorithm. We demonstrate that the ensemble setting is key to the network inference task, as only ensemble variants achieve top performance. As second contribution, we explore the effect of using rankwise averaged predictions of multiple ensemble algorithms as opposed to only one. We name this approach NIMEFI (Network Inference using Multiple Ensemble Feature Importance algorithms) and show that this approach outperforms all individual methods in general, although on a specific network a single method can perform better. An implementation of NIMEFI has been made publicly available. [less ▲]

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See detailConférence invitée: La démocratie multiculturelle : une idée obsolète ?
Martiniello, Marco ULg

Scientific conference (2014, March 25)

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See detailA new multifractal formalism based on wavelet leaders: detection of non concave and non increasing spectra (Part II)
Kleyntssens, Thomas ULg; Esser, Céline ULg; Nicolay, Samuel ULg

Conference (2014, March 25)

This talk follows "A new multifractal formalism based on wavelet leaders: detection of non concave and non increasing spectra (Part I)" given by Céline Esser. For real-life signals, it is impossible to ... [more ▼]

This talk follows "A new multifractal formalism based on wavelet leaders: detection of non concave and non increasing spectra (Part I)" given by Céline Esser. For real-life signals, it is impossible to compute the spectrum of singularities by using its definition. A multifractal formalism is used to approximate this spectrum. We present a new multifractal formalism for non concave and non increasing spectra based on wavelet leaders. In this talk, an implementation of this formalism is given and several numerical examples are presented. [less ▲]

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See detailA new multifractal formalism based on wavelet leaders : detection of non concave and non increasing spectra (Part I)
Esser, Céline ULg; Kleyntssens, Thomas ULg; Nicolay, Samuel ULg et al

Conference (2014, March 25)

Multifractal analysis is concerned with the study of very irregular signals. For such functions, the pointwise regularity may change widely from a point to another. Therefore, it is more interesting to ... [more ▼]

Multifractal analysis is concerned with the study of very irregular signals. For such functions, the pointwise regularity may change widely from a point to another. Therefore, it is more interesting to determine the spectrum of singularities of the signal, which is the Hausdorff dimension of the set of points which have the same Hölder exponent. The spectrum of singularities of many mathematical functions can be determined directly from its definition. However, for many real-life signals, the numerical determination of their Hölder regularity is not feasible. Therefore, one cannot expect to have a direct access to their spectrum of singularities and one has to find an indirect way to compute it. A multifractal formalism is a formula which is expected to yield the spectrum of singularities from quantities which are numerically computable. Several multifractal formalisms based on the wavelet coefficients of a signal have been proposed to estimate its spectrum. The most widespread of these formulas is the so-called thermodynamic multifractal formalism, based on the Frish-Parisi conjecture. This formalism presents two drawbacks: it can hold only for spectra that are concave and it can yield only the increasing part of the spectrum. This first problem can be avoided using Snu spaces. The second one can be avoided using a formalism based on wavelet leaders of the signal. In this talk, we propose a new multifractal formalism, based on a generalization of the Snu spaces using wavelet leaders. It allows to detect non concave and non increasing spectra. An implementation of this method is presented in the talk "A new multifractal formalism based on wavelet leaders: detection of non concave and non increasing spectra (Part II)" of T. Kleyntssens. [less ▲]

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See detailA Weak Local Irregularity Property in $S^\nu$ spaces
Clausel, Marianne; Nicolay, Samuel ULg

Conference (2014, March 25)

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See detailA multifractal-based climate analysis
Deliège, Adrien ULg; Nicolay, Samuel ULg

Conference (2014, March 25)

This work consists of a multifractal analysis of surface air temperature in Western and Eastern Europe. The wavelet leaders method enables us to exhibit the monofractal nature of these signals. Then, we ... [more ▼]

This work consists of a multifractal analysis of surface air temperature in Western and Eastern Europe. The wavelet leaders method enables us to exhibit the monofractal nature of these signals. Then, we define a climate classification relying on the Zygmund-Hölder spaces and show that it matches the Köppen classification. By doing so, we evidence the existing relation between the regularity of the temperature data (obtained through functional spaces) and the type of climate. Finally, we give a climatic interpretation of these results. [less ▲]

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See detailAgisme : quelles conséquences pour nos aînés?
Schroyen, Sarah ULg; Marquet, Manon ULg

Conference (2014, March 25)

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See detailAudition au Parlement fédéral relative à la possible instauration d'une circonscription électorale fédérale
Behrendt, Christian ULg

Conference given outside the academic context (2014)

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See detailRèglement Successions (650/2012) - aperçu général
Wautelet, Patrick ULg

Conference (2014, March 24)

This presentation gives a very general overview of the main principles on which the Succession Regulation is based.

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See detailSur quelles connaissances se baser pour évaluer l’état de santé des populations de truite commune (Salmo trutta)?
Gouraud, Véronique; Baran, Philippe; Bardonnet, Agnès et al

in Hydroécologie appliquée (2014)

Le retour au premier plan de la notion de santé des écosystèmes met en évidence la préoccupation de la société à mettre en oeuvre des mesures pour la protection des milieux anthropisés. Les critères ... [more ▼]

Le retour au premier plan de la notion de santé des écosystèmes met en évidence la préoccupation de la société à mettre en oeuvre des mesures pour la protection des milieux anthropisés. Les critères d’évaluation de la santé des peuplements piscicoles mis en oeuvre sont rarement débattus au sein de la communauté scientifique. L’exercice proposé ici devait permettre d’avoir ce débat sur la truite commune (Salmo trutta), espèce phare des cours d’eau situés en tête de bassin, qui représentent la majorité du réseau hydrographique français. La démarche visait à recueillir la conception qu’avait un nombre restreint d’experts, sur le fonctionnement de ces populations et sur les critères d’évaluation de leur fonctionnement. Les paramètres clé régulant chaque stade de développement ont été identifiés et hiérarchisés. Unconsensus s’est dégagé sur le fait que, dans l’état actuel des connaissances, le diagnostic peut être établi sur la base de l’analyse des paramètres abiotiques essentiels pour la biologie et, plus difficilement, sur l’analyse des paramètres biotiques. Pour tous les stades de développement, les paramètres identifiés sont liés à l’habitat (qualité du substrat, conditions hydrauliques, température et qualité de l’eau), l’hydrologie et la connectivité. Des connaissances demandent d’être acquises pour définir des critères biologiques. Cela implique de renforcer la surveillance biologique à long terme et les actions de recherche pour caractériser la variabilité des paramètres biologiques et identifier les échelles spatio-temporelles pertinentes et les processus fonctionnels. [less ▲]

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See detailGuest Research Workshop « Musique, identité et politique dans les villes multiculturelles »
Martiniello, Marco ULg

Scientific conference (2014, March 24)

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See detailG-Cube version 2.3.1 - Logiciel de cubage et de lotissement d'arbres
Lejeune, Philippe ULg; Quevauvillers, Samuel ULg; Handerek, Daphné ULg

Software (2014)

This software is dedicated to the volume estimation of tree list using as set of volume equations adapted to belgian forest species. A specific module takes in charge the creation and the price ... [more ▼]

This software is dedicated to the volume estimation of tree list using as set of volume equations adapted to belgian forest species. A specific module takes in charge the creation and the price calculation of trees assortments [less ▲]

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See detailGenetics of pituitary adenomas
Beckers, Albert ULg

Scientific conference (2014, March 22)

Detailed reference viewed: 11 (2 ULg)
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See detailWhy do heroin users refuse to participate in a heroin-assisted treatment trial?
Demaret, Isabelle ULg; Litran, Géraldine; Magoga, Cécile et al

in Heroin Addiction and Related Clinical Problems (2014), Epub ahead of print, March 22, 2014

Background: Heroin-assisted treatment (HAT) can improve the condition of heroin addicts who are resistant to other treatments. However, in a new HAT trial in Belgium, fewer subjects than expected were ... [more ▼]

Background: Heroin-assisted treatment (HAT) can improve the condition of heroin addicts who are resistant to other treatments. However, in a new HAT trial in Belgium, fewer subjects than expected were included. Aim: Our research team explored the reasons given by heroin users in explaining why they did not want to participate. Methods: In 2011, during the trial recruitment, we interviewed heroin users (n=52) who never took the opportunity to meet the research team during the recruitment process preceding the trial. Results: Of those 52 heroin users, 25 were afraid of the limited length of the HAT and 11 feared becoming more dependent as a result of HAT. Conclusion: A trial that was planned to last for a limited length of time may have demotivated heroin users who could otherwise have benefited from this new programme. [less ▲]

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See detailEntre jeu vidéo et littérature: l’écriture de fanfictions
Barnabé, Fanny ULg

Conference given outside the academic context (2014)

Detailed reference viewed: 14 (0 ULg)
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See detailLes jeunes et le génocide des Juifs : analyse socio-politique
Grandjean, Geoffrey ULg

Book published by De Boeck (2014)

La mémoire du génocide des Juifs est très présente dans les sociétés occidentales à travers des vecteurs de socialisation comme l’école, les médias, la famille, et plus récemment les réseaux sociaux et ... [more ▼]

La mémoire du génocide des Juifs est très présente dans les sociétés occidentales à travers des vecteurs de socialisation comme l’école, les médias, la famille, et plus récemment les réseaux sociaux et Internet. Quelles peuvent être les conséquences de la transmission de cette mémoire sur le développement des attitudes et des comportements politiques des jeunes ? C’est la question centrale de l’ouvrage qui présente les connaissances, les émotions et les valeurs mobilisées par les jeunes dans le cadre de groupes de discussion, et qui surtout les met en perspective avec leurs représentations et leurs perceptions des autorités politiques. Au final, plusieurs questions difficiles pour le futur émergent. En effet, à bien des égards, l’impact de la transmission de la mémoire du génocide des Juifs sur la socialisation politique des jeunes pose la question de l’éventualité de sa répétition, de son caractère exceptionnel, de sa compréhension, ou encore de l’effacement de sa mémoire dans la dynamique des générations et du temps qui passe. [less ▲]

Detailed reference viewed: 23 (3 ULg)