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See detailNeuropathies proximales du membre supérieur
WANG, François-Charles ULg

Conference (2014, October 04)

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See detailL'épaule un carrefour complexe
WANG, François-Charles ULg

Conference (2014, October 04)

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See detailEt si ce n'était pas un canal carpien
FERON, Frédéric ULg; WANG, François-Charles ULg

Conference (2014, October 04)

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See detailDiscussion de cas cliniques et atelier pratique
WANG, François-Charles ULg

Conference (2014, October 04)

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See detailKnowledge transfer from Belgian government to medical doctors
MORTELMANS, Katrien; REMMEN, Roy; BERKEIN, Philip et al

Conference (2014, October 02)

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See detailManuel d'analyse qualitative. Analyser sans compter ni classer
Lejeune, Christophe ULg

Book published by De Boeck (2014)

La méthode qualitative s'est dotée d'outils et de techniques : journal de bord, propriété, dimension, catégorie, échantillonnage, saturation, scénario, mémo et compte rendu, codage (ouvert, axial et ... [more ▼]

La méthode qualitative s'est dotée d'outils et de techniques : journal de bord, propriété, dimension, catégorie, échantillonnage, saturation, scénario, mémo et compte rendu, codage (ouvert, axial et sélectif). Cet ouvrage présente le rôle respectif de chacun de ces éléments et permet à tous de s'approprier la logique qui les sous-tend. S'appuyant sur des exemples issus de recherches réelles, il expose avec clarté comment conduire sa propre recherche. Il fournit des astuces développées par les praticiens les plus aguerris et permet ainsi au lecteur d'évaluer sa propre avancée dans le monde passionnant de la recherche qualitative. [less ▲]

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See detailIl ne suffit pas de lire les étiquettes, mais bien de discuter avec le producteur
Ozer, Pierre ULg

Article for general public (2014)

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See detailÉTUDE DU COMPLEXE ENZYMATIQUE DES SYMBIONTES DU TERMITE RETICULITERMES FLAVIPES (EX. SANTONENSIS)
Tarayre, Cédric ULg

Doctoral thesis (2014)

In the light of the economic, environmental and social context in which we live today, it has become obvious that the use of fossil fuels is not conceivable over the long term. Some alternatives have ... [more ▼]

In the light of the economic, environmental and social context in which we live today, it has become obvious that the use of fossil fuels is not conceivable over the long term. Some alternatives have therefore emerged in recent years. Second-generation biofuels are one of those alternatives and are based on the exploitation of vegetal biomass, also called lignocellulosic biomass. These materials require a hydrolysis step which can notably be achieved by enzymes. Some insects, such as termites, harbor complex microbial communities inside their digestive tracts. Those communities are able to produce enzymes which can be used in the field of the hydrolysis of vegetal biomass. This is what this thesis deals with. The main part of the work done focused on the research of enzyme-producing microorganisms (bacteria, mycetes and protists) responsible for the degradation of hemicelluloses and cellulose, the hydrolysis of which releases fermentable sugars. The insect which was used in this work was Reticulitermes flavipes (ex. santonensis), a lower termite, harboring a highly diversified internal microflora. This thesis describes the characterization of the microbial strains which were isolated and the enzymes they secrete. A complementary part of this research focussed on termites grown on artificial diets. The objective of this part was multiple : isolating enzyme-producing strains, not extractable according to the standard technique, and characterizing the microflora resulting from the applied artificial diets. This multidisciplinary approach was based on microscopy, proteomics, metagenomics and the assessment of metabolism applied to the different microbial consortia. [less ▲]

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See detailLiège. Où s’amorce le nouveau modèle économique wallon ? Où s’échoue le vieux modèle politique wallon ?
Artige, Lionel ULg

Conference given outside the academic context (2014)

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See detailAn asymptotic expansion-based method for a spectral approach in equivalent statistical linearization
Canor, Thomas ULg; Blaise, Nicolas ULg; Denoël, Vincent ULg

in Probabilistic Engineering Mechanics (2014), 38

Equivalent linearization consists in replacing a nonlinear system with an equivalent linear one whose parameters are tuned with regard to the minimization of a suitable function. In particular, the ... [more ▼]

Equivalent linearization consists in replacing a nonlinear system with an equivalent linear one whose parameters are tuned with regard to the minimization of a suitable function. In particular, the Gaussian equivalent linearization expresses the properties of an equivalent linear system in terms of the mean vector and the covariance matrix of the responses, which are the unknowns of the optimization problem in a spectral approach. Even though the system has been linearized, the resulting set of equations is nonlinear. The computational effort in this method pertains to the solution of a possibly large set of nonlinear algebraic equations involving integrals and inversions of full matrices. This work proposes to develop and apply an asymptotic expansion-based method to facilitate and to improve the statistical linearization for large nonlinear structures. The proposed developments demonstrate that for slightly to moderately coupled nonlinear systems, the equivalent linearization can be applied with an appropriate modal approach and eventually seen as a convergent series initiated with the stochastic response of a main decoupled linear system. With this method, the computational effort is attractively reduced, the conditioning of the set of nonlinear algebraic equations is improved and inversion of full transfer matrices and repeated integrations are avoided. The paper gives a formal description of the method and illustrates its implementation and performances with the computation of stationary responses of nonlinear structures subject to coherent random excitation fields. [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 detailRugose corals at the Tournaisian-Viséan transition in the Central Taurides (S Turkey) - Palaeobiogeography and Palaeoceanography of the Gondwana margin
Denayer, Julien ULg

in 4th International Palaeontological Congress, Mendoza, Abstracts volume (2014, October)

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See detailOptimal Assignment of Off-Peak Hours to Lower Curtailments in the Distribution Network
Merciadri, Luca ULg; Mathieu, Sébastien ULg; Ernst, Damien ULg et al

in Proceedings of the 5th European Innovative Smart Grid Technologies (ISGT) (2014, October)

We consider a price signal with two settings: off-peak tariff and on-peak tariff. Some loads are connected to specific electricity meters which allow the consumption of power only in off-peak periods ... [more ▼]

We consider a price signal with two settings: off-peak tariff and on-peak tariff. Some loads are connected to specific electricity meters which allow the consumption of power only in off-peak periods. Historically, off-peak periods were located during the night and on-peak periods during the day. Changing the assignment of off-peak periods is an easy method for distribution system operators to access to the flexibility of small consumers. This solution can be implemented quickly as the infrastructure needed already exists in some countries. We propose a mixed-integer linear model to assign optimally the off-peak hours so as to minimize a societal cost. This cost gathers together the cost of electricity, the financial losses due to energy curtailments of photovoltaic installations and the loads' wellbeing. Our model considers automatic tripping of inverters and constraints of the electrical distribution networks. Simulation results show that the new disposition of off-peak hours could reduce significantly the photovoltaic energy curtailed in the summer. [less ▲]

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See detailDynamic Simulation of Large-scale Power Systems Using a Parallel Schur-complement-based Decomposition Method
Aristidou, Petros ULg; Fabozzi, Davide; Van Cutsem, Thierry ULg

in IEEE Transactions on Parallel and Distributed Systems (2014), 25(10), 2561-2570

Power system dynamic simulations are crucial for the operation of electric power systems as they provide important information on the dynamic evolution of the system after an occurring disturbance. This ... [more ▼]

Power system dynamic simulations are crucial for the operation of electric power systems as they provide important information on the dynamic evolution of the system after an occurring disturbance. This paper proposes a robust, accurate and efficient parallel algorithm based on the Schur complement domain decomposition method. The algorithm provides numerical and computational acceleration of the procedure. Based on the shared-memory parallel programming model, a parallel implementation of the proposed algorithm is presented. The implementation is general, portable and scalable on inexpensive, shared-memory, multi-core machines. Two realistic test systems, a medium-scale and a large-scale, are used for performance evaluation of the proposed method. [less ▲]

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See detailGenetics of beef and milk fatty acid composition
Soyeurt, Hélène ULg; Beitz, Donald

in Garrick, D; Ruvinsky, A (Eds.) The genetics of cattle (2014)

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See detailModelling the hygrothermal behaviour of crop-based construction materials
Dubois, Samuel ULg

Doctoral thesis (2014)

In the context of developing sustainable buildings, crop-based construction materials appear as valuable products given their intrinsic environmental and technical qualities. Their ability to exchange ... [more ▼]

In the context of developing sustainable buildings, crop-based construction materials appear as valuable products given their intrinsic environmental and technical qualities. Their ability to exchange moisture with the surrounding environment and damping humidity peaks in rooms, referred to as moisture buffering, is often presented as a way to improve occupants comfort and otentially reduce the operational energy of the building. It is understandable why modelling their hygrothermal behaviour and evaluating the impact on indoor air volumes is essential during the design phases. This thesis explores themodelling of the hygrothermal behaviour of crop-basedmaterials with a numerical tool. The latter is developed in a widespread general computational environment that brings both modularity and interoperability. Three challenges are addressed: the improvement of mathematical description of crop-based materials in non-standard operating conditions, the improvement of materials properties determination, and the assessment of their impact at room-scale. Several experimental facilities are developed in parallel to validate the proposed approaches, focusing on two materials expected to improve indoor conditions: straw bales and lime-hemp concrete. Results show that the developedmodel allows improving the understanding and the characterization of these green materials at various scales of study. [less ▲]

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See detailPre-war Military Planning (Belgium)
Bechet, Christophe ULg

in Daniel, Ute; Gatrell, Peter; Janz, Oliver (Eds.) et al 1914-1918-online. International Encyclopedia of the First World War (2014)

Abstract: Since the Treaty of London in 1839, pre-war planning theories in Belgium oscillated between two positions: on one hand secure and defend which border would be endangered, on the other hand ... [more ▼]

Abstract: Since the Treaty of London in 1839, pre-war planning theories in Belgium oscillated between two positions: on one hand secure and defend which border would be endangered, on the other hand constitute in Antwerp a powerful national sanctuary. This concentration of most of the available military means in Antwerp was far more appropriate in the event of a French invasion. But this perspective decreased after the Franco-Prussian war in 1870, while the possibility of a trespassing by the two belligerents became greater and greater. The fortifications of Namur and Liège were voted by the Chambers in 1887 as a deterrent to both France and Germany. Nevertheless, without totally putting aside the defence of the Belgian southwestern border, high-ranking officers seemed to fear more and more a violation of the eastern border. Due to the completion of fortifications on the Meuse in 1892, German columns were supposed to move forward south of the river, through the Belgian Ardennes. On the eve of the Great War, King Albert I would have preferred to concentrate the army on the Meuse but his Chief of Staff selected a central position in order to maintain and secure his line of communication with Antwerp. The lack of a determined and “standardized” doctrine at the highest level of the army led to a “mixed” or compromise plan adopted in a hurry during the first days of mobilization in August 1914. [less ▲]

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See detailUsing XCO2 retrievals fo rassessing the long-term consistency of NDACC/FTIR data sets
Barthlott; Schneider, M; Hase, F et al

in Atmospheric Measurement Techniques. Papers in Open Discussion (2014), 7

Within the NDACC (Network for the Detection of Atmospheric Composition Change), more than 20 FTIR (Fourier–Transform InfraRed) spectrometers, spread worldwide, provide long-term data records of many ... [more ▼]

Within the NDACC (Network for the Detection of Atmospheric Composition Change), more than 20 FTIR (Fourier–Transform InfraRed) spectrometers, spread worldwide, provide long-term data records of many atmospheric trace gases. We present a method that uses measured and modelled XCO2 for assessing the consistency of these data records. Our NDACC XCO2 retrieval setup is kept simple so that it can easily be adopted for any NDACC/FTIR-like measurement made since the late 1950s. By a comparison to coincident TCCON (Total Carbon Column Observing Network) measurements, we empirically demonstrate the useful quality of this NDACC XCO2 product (empirically obtained scatter between TCCON and NDACC is about 4‰ for daily mean as well as monthly mean comparisons and the bias is 25 ‰). As XCO2 model we developed and used a simple regression model fitted to CarbonTracker results and the Mauna Loa CO2 in-situ records. A comparison to TCCON data suggests an uncertainty of the model for monthly mean data of below 3 ‰. We apply the method to the NDACC/FTIR spectra that are used within the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) and demonstrate that there is a good consistency for these globally representative set of spectra measured since 1996: the scatter between the modelled and measured XCO2 on a yearly time scale is only 3 ‰. [less ▲]

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