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
Full Text
See detailComparaison par simulation de 3 types d'unités d'échantillonage en futaies feuillues de hêtre (Fagus silvatica L.).
Hebert, Jacques ULg; Rondeux, Jacques ULg; Laurent, C.

in Annales des Sciences Forestières (1988), 45(3), 209-222

This study is dealing with the choice of the size and the type of sampling units which could be used in inventories of beech stands (Fagus silvatica L.). Two experimental areas of 16 hectares have been ... [more ▼]

This study is dealing with the choice of the size and the type of sampling units which could be used in inventories of beech stands (Fagus silvatica L.). Two experimental areas of 16 hectares have been considered in evenaged and unevenaged structures. Three types of sampling units were studied : fixed circular plots, Bitterlich plots (non fixed circular plots) and circular plots including a minimum of number of trees (15-20). As regards to the estimations of basal area and number of trees per hectare there is no significative difference between plots of fixed area and plots including a minimum number of trees even if plot sizes and stand structure vary. As expected, compared to the other methods, the Bitterlich plots give little more precise estimations of basal area and less precise estimations of number of trees. The plots with a minimum number of trees would give higher values compared to the other types of plots but no significative difference have been observed. Numerous simulations show that in case of a fixed total cost the use of a great number of small units or of a limited number of large units has little effect on the standard error of estimations. The concept of minimum number of trees (15-20) seems to be valuable according to a compromise between precision and cost. To avoid a risk of bias in stands including large empty zones, it is preferable to use plot radii suitable to normal conditions. [less ▲]

Detailed reference viewed: 29 (3 ULg)
Full Text
Peer Reviewed
See detailComparaison pratique de quelques méthodes d'analyse discriminante
Lazaar, N.; Palm, Rodolphe ULg

in Biométrie-Praximétrie (1994), 34

Dans cette étude, on compare les performances des trois méthodes d'analyse discriminante suivantes : analyse discriminante linéaire, analyse discriminante quadratique et analyse discriminante logistique ... [more ▼]

Dans cette étude, on compare les performances des trois méthodes d'analyse discriminante suivantes : analyse discriminante linéaire, analyse discriminante quadratique et analyse discriminante logistique. Les performances sont étudiées dans le cas de données réelles, en envisageant diverses transformations de variables destinées à modifier les conditions de normalité et d'égalité des variances entre populations. Aucune différence significative de performances entre méthodes n'a pu être mise en évidence au niveau de signification de 0,05. Par contre, les performances des trois méthodes diminuent quand les distributions des variables sont nettement non normales ou de variances très inégales. Différentes estimations des taux d'erreur ont également été comparées : resubstitutin, extraction-insertion et utilisation d'un échantillon-test. Les résultats ont montré que, par rapport à l'utilisation d'échantillons-tests, la méthode de resubstitution sous-estime le taux d'erreur. Cette sous-estimation est de l'ordre de 13 % du taux d'erreur réel. La méthode d'extraction-insertion donne par contre des résultats très semblables à la méthode utilisant un échantillon-test. [less ▲]

Detailed reference viewed: 19 (1 ULg)
Full Text
Peer Reviewed
See detailComparaison quantitative de différentes techniques de restauration rapide dans les réseaux IP/MPLS
Mélon, Laurent; Leduc, Guy ULg

in Obaid, A. (Ed.) Ingénierie des protocoles - Réseaux mobiles et ad hoc, qualité de service, multimédia, ingénierie de trafic (2002, May 27)

This article is dealing with a quantitative comparison of different fast restoration approaches in the context of a Multi-Protocol Label Switching (MPLS) network. The objective is to analyse the general ... [more ▼]

This article is dealing with a quantitative comparison of different fast restoration approaches in the context of a Multi-Protocol Label Switching (MPLS) network. The objective is to analyse the general behaviour of these approaches (local rerouting, edge-to-edge rerouting, ...) in case of failure by means of simulations. This study is realised in the context of Best Effort only traffic, routing being done with a shortest paths algorithm. Many papers justify the choice between an edge-to-edge or a local scheme by means of intuition and then present a new algorithm for routing backup paths which try to optimize some parameters. Our approach aims to clarify the situation by comparing by means of concrete results the pros and cons of each mechanism. [less ▲]

Detailed reference viewed: 83 (3 ULg)
Full Text
See detailComparaisons calculs-essais pour l'éprouvette cylindrique
Beckers, Pierre ULg; Debongnie, Jean-François ULg; Masset, Luc ULg

Report (1996)

In this first application of the machining simulation tool prototype, great difficulties were encountered in the interpretaion of the physical test. In fact, parasitic deformations occured, with a three ... [more ▼]

In this first application of the machining simulation tool prototype, great difficulties were encountered in the interpretaion of the physical test. In fact, parasitic deformations occured, with a three-lobed form. This implied the necessity of filtering the experimental data and a physical interpretation of the undue deformation. A theoretical study is performed, leading to the result that this phenomenon is due to the combined effect of the clearance of the clamping jaws and the pre-stress of the dead center. [less ▲]

Detailed reference viewed: 32 (3 ULg)
Full Text
See detailComparaisons calculs-essais pour le carter d'alimentation d'huile TA96
Beckers, Pierre ULg; Debongnie, Jean-François ULg; Masset, Luc ULg

Report (1996)

On this application, the computed results were in the opposite direction as compared to the physical tests. A sound analysis led to the result that a parasitic deformation was due to clamping deformations ... [more ▼]

On this application, the computed results were in the opposite direction as compared to the physical tests. A sound analysis led to the result that a parasitic deformation was due to clamping deformations. In fact, the three supports of the work were found to be unsufficiently coplanar. [less ▲]

Detailed reference viewed: 29 (4 ULg)
Full Text
See detailComparaisons calculs-essais pour le palier de suspension J64
Beckers, Pierre ULg; Debongnie, Jean-François ULg; Masset, Luc ULg

Report (1996)

This report is devoted to the J64 suspension bearing benchmark. Unfortunately, the actual machining led to considerable vibrations, rendering any comparison impossible.

Detailed reference viewed: 24 (3 ULg)
Full Text
Peer Reviewed
See detailComparant mais pas fondateur
Caprasse, Olivier ULg

in Revue de Jurisprudence de Liège, Mons et Bruxelles (2002)

Detailed reference viewed: 27 (3 ULg)
See detailLe comparatisme du P. Thomassin
Droixhe, Daniel ULg

in De Clercq, J.; Desmet, P. (Eds.) Florilegium historiographiae linguisticae : Études d'historiographie de la linguistique et de grammaire comparée : à la mémoire de Maurice Leroy (1994)

Detailed reference viewed: 15 (4 ULg)
See detailComparatisme et transversalité
Delville, Michel ULg; Belloi, Livio ULg

Scientific conference (2006, October 11)

Detailed reference viewed: 10 (1 ULg)
Full Text
Peer Reviewed
See detailComparatisme institutionnel et analyse sémiotique du discours métalittéraire francophone : problèmes d’une recherche en cours
Provenzano, François ULg

in Wilhelm, Frank; Baustert, Raymond; Colas-Blaise, Marion (Eds.) et al Le Blé en herbe : actes des premières Journées des Jeunes chercheurs/euses en Littérature et Linguistique françaises (2007)

Detailed reference viewed: 23 (0 ULg)
See detailComparative advertising versus non comparative advertising in social marketing : the case of tap water
Delcourt, Cécile ULg

Master of advanced studies dissertation (2007)

Detailed reference viewed: 38 (6 ULg)
Full Text
Peer Reviewed
See detailComparative analyses of salivary proteins from three aphid species
Vandermoten, Sophie ULg; Harmel, Nicolas; Mazzucchelli, Gabriel ULg et al

in Insect Molecular Biology (2013), under publication

Detailed reference viewed: 59 (11 ULg)
Full Text
Peer Reviewed
See detailComparative analysis between analytical approximations and numerical solutions describing recession flow in unconfined hillslope aquifers
Rocha, David; Feyen, Jan; Dassargues, Alain ULg

in Hydrogeology Journal (2007), 15(6), 1077-1091

Recession flow of aquifers from a hillslope can be described by the non-linear Boussinesq equation. Under strong assumptions and for specific conceptual formulations, different authors derived analytical ... [more ▼]

Recession flow of aquifers from a hillslope can be described by the non-linear Boussinesq equation. Under strong assumptions and for specific conceptual formulations, different authors derived analytical approximations or linearized versions to this partial differential equation. A comparative analysis between some analytical approximations of the Boussinesq equation and the numerical solution of the recession flow of an unconfined homogeneous aquifer (horizontal, inclined and concave aquifer floor) was carried out. The objective was to define the range where the analytical solutions approximate the numerical solution. The latter was considered in this study as the reference method, because it requires fewer assumptions. From the considered analytical approximations, exponential decay relationships were found to be mainly valid for fine domain materials when horizontal, mild slopes (less than 2%) and concave aquifer floors were considered, but failed to reproduce coarse aquifer numerical model outflows, in contrast to the quadratic decay relationship, which better reproduce outflows in such domains. On the basis of the comparative analysis, it has been found that recession flows obtained with the considered analytical approximations yield similar values only for certain ranges of aquifer properties and geometries. [less ▲]

Detailed reference viewed: 74 (7 ULg)
Full Text
Peer Reviewed
See detailA comparative analysis between the time trade-off and the willingness to pay approaches in hip and knee osteoarthritis
Ethgen, Olivier ULg; Tancredi, Annalisa ULg; Lejeune, Eric ULg et al

in Osteoporosis International (2002, November), 13(Suppl. 3), 47

Detailed reference viewed: 33 (8 ULg)
Peer Reviewed
See detailComparative analysis of SST interannual variability in the Western Mediterranean Sea and North-East Atlantic Ocean
Djenidi, Salim ULg; Kostianoy, Andrey; Lacroix, Geneviève et al

in Annales Geophysicae. Series B, Terrestrial and Planetary Physics (1998), 16(suppl. II),

Detailed reference viewed: 5 (0 ULg)
Full Text
Peer Reviewed
See detailComparative analysis of airglow emissions in terrestrial planets, observed with VIRTIS-M instruments on board Rosetta and Venus Express
Migliorini, A.; Piccioni, G.; Capaccioni, F. et al

in Icarus (2013), 226

Airglow emissions are optimal processes to investigate the chemistry and dynamics in planetary atmospheres. In this study, we focus on the O2 and OH airglow emissions in Venus, Earth, and Mars atmospheres ... [more ▼]

Airglow emissions are optimal processes to investigate the chemistry and dynamics in planetary atmospheres. In this study, we focus on the O2 and OH airglow emissions in Venus, Earth, and Mars atmospheres, which are controlled by chemical reactions common to the three planets. By studying these phenomena on Venus, Earth, and Mars using similar instruments, we are able to derive information about their photochemistry and the physical conditions of the atmospheres, but also to constrain the dynamics responsible for transport of atomic oxygen, ozone and other minor species. After a review of the nightglow emissions observed in the Venus atmosphere, we analyze the O2 and OH airglow emissions in the Earth's atmosphere observed during the 3 swing-bys of our planet by the Rosetta spacecraft. We also report the detection of the O2 nightglow emission in the Mars atmosphere, observed in February 2007 during the Rosetta fly-by of the planet. The airglow characteristics are in agreement with the measurements obtained from sensors on board Mars Express. [less ▲]

Detailed reference viewed: 17 (1 ULg)
Full Text
Peer Reviewed
See detailA Comparative Analysis of Coffee Fair Trade Arena in Tanzania and Nicaragua
Pirotte, Gautier ULg; Pleyers, Geoffrey; Poncelet, Marc ULg

in Development in Practice (2006), 16(5),

Les activités de commerce équitable dans le Sud sont en général étudiées par rapport aux buts internes des organisations de commerce équitable elles-mêmes. Cet article soutient qu’il est également ... [more ▼]

Les activités de commerce équitable dans le Sud sont en général étudiées par rapport aux buts internes des organisations de commerce équitable elles-mêmes. Cet article soutient qu’il est également essentiel de prendre en compte l’“arène” ou ensemble d’interactions plus générales de commerce équitable. Les auteurs se concentrent sur les “arènes” du café commerce équitable de la Tanzanie et du Nicaragua et étudient le rôle de quatre acteurs clés : les petits producteurs, les coopératives, les partenaires de développement et les autorités publiques. En utilisant des données comparatives issues d’études sur le terrain menées en 2002 et 2003, cet article fait ressortir des questions clés nationales et internationales qui affectent les producteurs locaux. Illustrant l’évolution différente du commerce équitable selon le contexte, cet article examine la manière dont le mouvement des coopératives au Nicaragua a été consolidé par la production du commerce équitable, à la différence de la situation en Tanzanie. Il conclut en se penchant sur certains des défis auxquels se confronte le commerce équitable, y compris comment concilier les exigences du marché et le renforcement de la solidarité. [less ▲]

Detailed reference viewed: 34 (4 ULg)