Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
See detailContributions à la didactique de la statistique
Bair, Jacques ULg; Henry, Valérie ULg

Book published by Editions de l'Université de Liège (2005)

Cet ouvrage contient une série d'articles rédigés par des collègues et des anciens collaborateurs du professeur L. Bragard qui ont tenu à rendre hommage à ce dernier. De nombreux thèmes liés à la ... [more ▼]

Cet ouvrage contient une série d'articles rédigés par des collègues et des anciens collaborateurs du professeur L. Bragard qui ont tenu à rendre hommage à ce dernier. De nombreux thèmes liés à la didactique de la statistique sont abordés. [less ▲]

Detailed reference viewed: 33 (0 ULg)
Full Text
Peer Reviewed
See detailContributions à la fortune de la "Cène" de Léonard de Vinci en France : la copie de Saint-Germain l'Auxerrois à Paris et la copie de Saint-Martin à Saint Martin des Monts
Fagnart, Laure ULg

in Raccolta Vinciana (2005), XXXI

Cet article fournit une analyse détaillée de l’une des copies anciennes de la "Cène" de Léonard de Vinci, celle qui est conservée dans l’église Saint-Germain l’Auxerrois de Paris depuis 1651 au moins. Il ... [more ▼]

Cet article fournit une analyse détaillée de l’une des copies anciennes de la "Cène" de Léonard de Vinci, celle qui est conservée dans l’église Saint-Germain l’Auxerrois de Paris depuis 1651 au moins. Il s’attache à en retracer l’histoire mais aussi à en identifier le commanditaire : la découverte de signatures, soigneusement grattées dans la couche picturale, permet de supposer qu’il s’agit de Jean V Burdelot, issu d’une famille de notaires et de secrétaires du roi mais aussi procureur général du Sénat de Milan. Comme d’autres Français en charge à Milan, Burdelot a pu visiter le réfectoire du couvent Santa Maria delle Grazie et désirer conserver un souvenir de la "Cène", en commandant une copie. Cet article présente également une autre réplique ancienne du chef-d’œuvre de Léonard, jusqu’alors inconnue de la critique, le relief qui est conservé dans l’église de Saint-Martin-des-Monts (La Ferté-Bernard). [less ▲]

Detailed reference viewed: 56 (8 ULg)
Full Text
See detailContributions à la modélisation des incendies dans les bâtiments et de leurs effets sur les structures
Franssen, Jean-Marc ULg

Post doctoral thesis (1997)

Besides the ntroductory and concluding chapter, the body of the thesis is in three parts. The firt part addresses numerical simulation of structural fire behaviour. The second part is dedicated to simple ... [more ▼]

Besides the ntroductory and concluding chapter, the body of the thesis is in three parts. The firt part addresses numerical simulation of structural fire behaviour. The second part is dedicated to simple caluclation methods appropriate for a design office. The this part is dedicated to some aspects of fire safety engineering. In addition, the thesis includes three fire related appendices dedicated to: 1) the evaluation of shear resistance of prestressed concrete beams, 2) the effect of columns failure on the stability of an entire structure, 3) the residual stresses in hot-rolled steel structures sections. [less ▲]

Detailed reference viewed: 267 (14 ULg)
Full Text
See detailContributions aux algorithmes d'intégration temporelle conservant l'énergie en dynamique non-linéaire des structures
Noels, Ludovic ULg

Doctoral thesis (2004)

Les points fondamentaux de mes recherches consistent en une étude mathématique des algorithmes d'intégration temporelle d'une discrétisation de type éléments-finis. Les algorithmes traditionnels d ... [more ▼]

Les points fondamentaux de mes recherches consistent en une étude mathématique des algorithmes d'intégration temporelle d'une discrétisation de type éléments-finis. Les algorithmes traditionnels d'intégration temporelle (Newmark, famille alpha-généralisée, ...) peuvent introduire numériquement de l'énergie dans les systèmes non-linéaires. De nouveaux algorithmes sont dès lors apparus pour permettre d'éviter cette perte de stabilité. Lors de mes études, ces algorithmes ont été étendus, de manière originale, au traitement de la plasticité à l'aide d'un modèle de type hypo-élastique. Ils ont également été étendus au traitement généralisé, dans le cadre tridimensionnel, de l'interaction de contact. Ensuite la mise en oeuvre d'une méthode permettant de combiner, au cours du temps un algorithme implicite stable, avec un algorithme explicite traditionnel a été envisagée. La stabilité du passage d'une méthode explicite vers une méthode implicite a été démontrée par nos soins. Une définition originale de critères automatiques de choix de basculement entre les méthodes a été proposée. Des exemples numériques complexes ont mis en évidences les bonnes performances des algorithmes développés, tant du point de vue de la précision des résultats - confrontés aux résultats expérimentaux si ces derniers existent -, que du point de vue de la réduction des coûts de calcul lorsque la méthode combinée est utilisée. [less ▲]

Detailed reference viewed: 288 (34 ULg)
Full Text
Peer Reviewed
See detailContributions du sommeil a la consolidation mnésique
Maquet, Pierre ULg; Matarazzo; Foret, Ariane ULg et al

in Biologie Aujourd'hui (2010), 204(2), 139-143

Detailed reference viewed: 85 (41 ULg)
Full Text
Peer Reviewed
See detailContributions of a 3D numerical environment for architectural sketches.
Mayeur, A.; Darses, F.; Leclercq, Pierre ULg

in Lecture Notes in Computer Science (2008)

Detailed reference viewed: 28 (4 ULg)
Full Text
Peer Reviewed
See detailContributions of benthic and planktonic primary producers to nitrate and ammonium uptake fluxes in a nutrient-poor shallow coastal area (Corsica, NW Mediterranean)
Lepoint, Gilles ULg; Gobert, Sylvie ULg; Dauby, Patrick ULg et al

in Journal of Experimental Marine Biology and Ecology (2004), 302(1), 107-122

By using the stable isotope N-15, we have measured in situ the uptake of nitrate and ammonium by the seagrass Posidonia oceanica, its leaf epiphyte community, the brown macroalgae Halopteris scoparia and ... [more ▼]

By using the stable isotope N-15, we have measured in situ the uptake of nitrate and ammonium by the seagrass Posidonia oceanica, its leaf epiphyte community, the brown macroalgae Halopteris scoparia and the suspended particulate organic matter (SPOM). In Revellata Bay (Gulf of Calvi, Westem Corsica), which is a very nutrient-poor region, the specific uptake rates (V) (mug N g N 1 h(- 1)) of SPOM measured at ambient concentrations are 10-1000 higher than those of benthic primary producers. Macroalgae have intermediary v, between the seagrass leaf and leaf epiphytes. V are quite variable and the reasons for this variability remain unclear. Despite the difference of specific uptake rates found between benthic and pelagic primary producers, when integrating the uptake fluxes for a water Column of 10 m depth, the contribution of benthic primary producers to N uptake fluxes (g N m(-) (2) h(-) (1)) is significant, corresponding on average to 40% of total uptake flux. This results from the dominance in terms of N biomass of benthic primary producers in this shallow nutrient-poor area. When reported for the entire volume of the Revellata Bay, the contribution of benthic primary producers is reduced to 5 - 10% of total N uptake flux. Although this contribution could appear relatively low, it results in a significant direct transfer of inorganic nitrogen from the water column to the benthic compartment. By this transfer, the benthic plants act as a biological pump incorporating the pelagic N into the benthic compartment for a time longer than the characteristic time of phytoplankton dynamics (month-years vs. day-week). (C) 2003 Elsevier B.V. Alt rights reserved. [less ▲]

Detailed reference viewed: 47 (16 ULg)
Full Text
See detailContributions of collaborative e-annotations in project-based teaching
Leclercq, Pierre ULg; Ben Rajeb, Samia ULg

Scientific conference (2012, December)

Detailed reference viewed: 10 (0 ULg)
Full Text
Peer Reviewed
See detailContributions of experimental mouse models to the understanding of African trypanosomiasis.
Antoine-Moussiaux, Nicolas ULg; Magez, Stefan; Desmecht, Daniel ULg

in Trends in Parasitology (2008), 24(9), 411-8

African trypanosomiasis is the collective name for a wide variety of trypanosome infections that affect humans and livestock. In recent years, experimental mice infection models have provided new insights ... [more ▼]

African trypanosomiasis is the collective name for a wide variety of trypanosome infections that affect humans and livestock. In recent years, experimental mice infection models have provided new insights into both human and animal trypanosomiasis. Mouse models seem to be a valuable and versatile tool in trypanosomiasis-associated pathology and immunology research and highlight the variety shown by African trypanosomiases. Indeed, inbred mouse strains have enabled the study of genetic determinants of susceptibility and of the roles of anti-parasite antibodies, inflammatory mediators and anti-inflammatory mediators for each trypanosome species. Remarkable advances relating to the encephalitic stage of sleeping sickness have also been achieved thanks to murine models. The different contributions of murine models to the African trypanosomiases knowledge are presented here. Future search directions are finally proposed, with respect to mouse model opportunities and limitations. [less ▲]

Detailed reference viewed: 28 (6 ULg)
Full Text
See detailThe contributions of pairs of parallel surfaces in a simple analytical model of room reverberation
Embrechts, Jean-Jacques ULg

in I.C.A. (Ed.) Proceedings of the 2013 ICA Congress (2013, June)

Detailed reference viewed: 44 (15 ULg)
Full Text
Peer Reviewed
See detailContributions of the driven process and the loading-unloading process during substorms: A study based on the IMAGE-SI12 imager
Blockx, Caroline ULg; Gérard, Jean-Claude ULg; Coumans, Valérie ULg et al

in Journal of Geophysical Research (2009), 114

Substorm energetics has been shown to have two components, the "loading-unloading'' component releasing energy previously stored in the tail and the "directly driven'' component dissipating simultaneously ... [more ▼]

Substorm energetics has been shown to have two components, the "loading-unloading'' component releasing energy previously stored in the tail and the "directly driven'' component dissipating simultaneously fed solar wind energy. Previous studies disagree about the relative importance of each process. The SI12 spectral imager onboard the IMAGE satellite provides images of the Doppler-shifted Lyman alpha auroral emission at 121.8 nm every 2 min. It has been used to determine the auroral intensity during substorms, which may be compared to the solar wind characteristics and interplanetary magnetic field components before and/or after substorm onsets. In this study, we analyze 256 substorms between June 2000 and December 2002, which satisfy criteria relative to the viewing conditions. We compare the mean nightside intensity during the expansion phase with the magnetic open flux, the epsilon parameter, and other coupling functions (used as proxies of transfer of solar wind energy to the magnetosphere) integrated over the growth phase or the expansion phase. The mean auroral intensity during the expansion phase correlates well with coupling functions integrated over the growth phase. We also find that the correlation between the auroral precipitation during the expansion phase and the coupling functions integrated over the expansion phase is lower but still significant. This implies that, even though both mechanisms contribute to the energy precipitated during substorms, the loading-unloading process is statistically dominant. [less ▲]

Detailed reference viewed: 22 (3 ULg)
Full Text
Peer Reviewed
See detailContributions possibles des innovations genetiques pour l'amelioration de la competitivite des filieres cotonnieres africaines.
Mergeai, Guy ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2006), 10(4), 345-350

Detailed reference viewed: 5 (2 ULg)
See detailContributions théorique et expérimentale au calcul de la résistance à l'avancement des convois poussés en navigation dans les voies d'eau de sections limitées
Marchal, Jean ULg

in Annales des Travaux Publics de Belgique = Tijdschrift der Openbare Werken van Belgie (1977), (1 et 2), 77

Detailed reference viewed: 39 (11 ULg)
Full Text
See detailContributions to Batch Mode Reinforcement Learning
Fonteneau, Raphaël ULg

Doctoral thesis (2011)

This dissertation presents various research contributions published during these four years of PhD in the field of batch mode reinforcement learning, which studies optimal control problems for which the ... [more ▼]

This dissertation presents various research contributions published during these four years of PhD in the field of batch mode reinforcement learning, which studies optimal control problems for which the only information available on the system dynamics and the reward function is gathered in a set of trajectories. We first focus on deterministic problems in continuous spaces. In such a context, and under some assumptions related to the smoothness of the environment, we propose a new approach for inferring bounds on the performance of control policies. We also derive from these bounds a new inference algorithm for generalizing the information contained in the batch collection of trajectories in a cautious manner. This inference algorithm as itself lead us to propose a min max generalization framework. When working on batch mode reinforcement learning problems, one has also often to consider the problem of generating informative trajectories. This dissertation proposes two different approaches for addressing this problem. The first approach uses the bounds mentioned above to generate data tightening these bounds. The second approach proposes to generate data that are predicted to generate a change in the inferred optimal control policy. While the above mentioned contributions consider a deterministic framework, we also report on two research contributions which consider a stochastic setting. The first one addresses the problem of evaluating the expected return of control policies in the presence of disturbances. The second one proposes a technique for selecting relevant variables in a batch mode reinforcement learning context, in order to compute simplified control policies that are based on smaller sets of state variables. [less ▲]

Detailed reference viewed: 90 (17 ULg)
Full Text
See detailContributions to combinatorics on words in an abelian context and covering problems in graphs
Vandomme, Elise ULg

Doctoral thesis (2015)

This thesis dissertation is divided into two (distinct but connected) parts that reflect the joint PhD. We study and we solve several questions regarding on the one hand combinatorics on words in an ... [more ▼]

This thesis dissertation is divided into two (distinct but connected) parts that reflect the joint PhD. We study and we solve several questions regarding on the one hand combinatorics on words in an abelian context and on the other hand covering problems in graphs. Each particular problem is the topic of a chapter. In combinatorics on words, the first problem considered focuses on the 2-regularity of sequences in the sense of Allouche and Shallit. We prove that a sequence satisfying a certain symmetry property is 2-regular. Then we apply this theorem to show that the 2-abelian complexity functions of the Thue--Morse word and the period-doubling word are 2-regular. The computation and arguments leading to these results fit into a quite general scheme that we hope can be used again to prove additional regularity results. The second question concerns the notion of return words up to abelian equivalence, introduced by Puzynina and Zamboni. We obtain a characterization of Sturmian words with non-zero intercept in terms of the finiteness of the set of abelian return words to all prefixes. We describe this set of abelian returns for the Fibonacci word but also for the Thue--Morse word (which is not Sturmian). We investigate the relationship existing between the abelian complexity and the finiteness of this set. In graph theory, the first problem considered deals with identifying codes in graphs. These codes were introduced by Karpovsky, Chakrabarty and Levitin to model fault-diagnosis in multiprocessor systems. The ratio between the optimal size of an identifying code and the optimal size of a fractional relaxation of an identifying code is between 1 and 2 ln(|V|)+1 where V is the vertex set of the graph. We focus on vertex-transitive graphs, since we can compute the exact fractional solution for them. We exhibit infinite families, called generalized quadrangles, of vertex-transitive graphs with integer and fractional identifying codes of order |V|^a with a in {1/4,1/3,2/5}. The second problem concerns (r,a,b)-covering codes of the infinite grid already studied by Axenovich and Puzynina. We introduce the notion of constant 2-labellings of weighted graphs and study them in four particular weighted cycles. We present a method to link these labellings with covering codes. Finally, we determine the precise values of the constants a and b of any (r,a,b)-covering code of the infinite grid with |a-b|>4. This is an extension of a theorem of Axenovich. [less ▲]

Detailed reference viewed: 96 (31 ULg)