Publications ORBi OA     Results 26961-26980 of 53532.   1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354   Mutliproxy investigation of climatic and anthropogenic changes in a Baltic bog (N. Poland) during the last millenniumDe Vleeschouwer, François; Fagel, Nathalie ; Piotrowska, Natalia et alPoster (2010)Detailed reference viewed: 24 (2 ULg) Benthic remineralisation in the Northeast European Continental margin (Northern Biscay Bay)Suykens, K.; Schmidt, S.; Delille, Bruno et alPoster (2010)Detailed reference viewed: 21 (1 ULg) Atlas de Belgique: tome 2, Paysages, monde rural et agricultureVan Hecke, Etienne; Antrop, Marc; Schmitz, Serge et alBook published by Academia (2010)Detailed reference viewed: 361 (37 ULg) Education aux médias : document pédagogique à destination des étudiantsVan Cauwenberge, Geneviève ; Poskin, Camille Learning material (2010)Detailed reference viewed: 719 (125 ULg) Detailed inundation modelling using high resolution DEMsErpicum, Sébastien ; Dewals, Benjamin ; Archambeau, Pierre et alin Engineering Applications of Computational Fluid Mechanics (2010), 2(4), 196-208With the availability of high resolution DEMs, relevant and detailed inundation maps may now be routinely computed provided that suited flow models are available. The full 2D flow model presented in this ... [more ▼]With the availability of high resolution DEMs, relevant and detailed inundation maps may now be routinely computed provided that suited flow models are available. The full 2D flow model presented in this paper has been used to compute such maps on 800 km of the main rivers of the Walloon Region in Belgium. The use of grid spacing of 1 m, similar to the DEM resolution, enables to accurately predict the pattern of flood depth. This is confirmed by several application examples, which also demonstrate the ability of the model to reproduce depth measurements for a wide range of flood discharges without the need for recalibration of the roughness coefficient. The numerical model has been systematically validated by comparison with observations during recent real flood events. It shows a very good agreement with field data, in particular regarding free surface elevations and inundation extension. [less ▲]Detailed reference viewed: 305 (50 ULg) Development of upland cotton plants highly resistant to the reniform nematode from the G. Hirsutum x G. Thurberi x G. Longicalyx hybridMergeai, Guy ; Konan, N.O; Baudoin, Jean-Pierre in Proceedings of the beltwide cotton improvement conference (2010)Detailed reference viewed: 17 (3 ULg) Une situation fondamentale pour le concept de limite ? Question de langage, de culture ? Comment la Théorie Anthropologique du Didactique permet-elle de problématiser cette question ?Job, Pierre ; Schneider-Gilot, Marguerite in Actes du IIe congrès international sur la TAD (2010)Detailed reference viewed: 20 (2 ULg) Does Retirement Affect Cognitive Functioning?Bonsang, Eric; Adam, Stéphane ; Perelman, Sergio Report (2010)This paper analyzes the effect of retirement on cognitive functioning using two large scale surveys. On the one hand the HRS, a longitudinal survey among individuals aged 50+ living in the United States ... [more ▼]This paper analyzes the effect of retirement on cognitive functioning using two large scale surveys. On the one hand the HRS, a longitudinal survey among individuals aged 50+ living in the United States, allows us to control for individual heterogeneity and endogeneity of the retirement decision by using the eligibility age for Social Security as an instrument. On the other hand, a comparable international European survey, SHARE, allows us to identify the causal effect of retirement on cognitive functioning by using the cross-country differences in the age-pattern of retirement. The results highlight in both cases a significant negative, and quantitatively comparable, effect of retirement on cognitive functioning. Our results suggest that promoting labor force participation of older workers is not only desirable to insure the viability of retirement schemes, but it could also delay cognitive decline, and thus the occurrence of associated impairments at older age. [less ▲]Detailed reference viewed: 55 (10 ULg) Développement territorial et économie. Dix ans de recherches CPDT sur les activités économiquesMerenne-Schoumaker, Bernadette ; Lambotte, Jean-Marc ; Bastin, Aurore et alin Territoire(s) Wallon(s) (2010), 4Major common thread of all the work undertaken by the CPDT researchers into economic matters : optimisation of economic activities with construction of decision-making assistance tools seeking to ... [more ▼]Major common thread of all the work undertaken by the CPDT researchers into economic matters : optimisation of economic activities with construction of decision-making assistance tools seeking to encourage activity location that is more in phase with the sustainable development of territories. Three researches are retained : to make a match between the mobilty profiles of the compagnies and the accessibility profiles of the places, to use the land more parsimoniously in the economic activity areas and to encourage a diversity of functions by developing an environmental zoning. [less ▲]Detailed reference viewed: 176 (14 ULg) statistiqueDozo, Björn-Olav in Aron, Paul; Saint-Jacques, Denis; Viala, Alain (Eds.) Le Dictionnaire du littéraire (2010)Detailed reference viewed: 68 (8 ULg) Le Comité France-Amérique et l’Alliance française à MontréalDozo, Björn-Olav in Luneau, Marie-Pier; Mellot, Jean-Dominique; Montreuil, Sophie (Eds.) et al Passeurs d'histoire(s). Figures des relations France-Québec en histoire du livre (2010)Detailed reference viewed: 39 (2 ULg) Environmental control of carbon fluxes in forest ecosystems in France: a comparison between temperate, Mediterranean and tropical forestsLongdoz, Bernard ; Granier, André; Loustau, Denis et alin Loustau, Denis (Ed.) Forests, carbon cycle and climate change (2010)Detailed reference viewed: 28 (1 ULg) Soil surface water content estimation by full-waveform GPR signal inversion in the presence of thin layersMinet, Julien ; Lambot, Sébastien; Slob, Evert C. et alin IEEE Transactions on Geoscience and Remote Sensing (2010), 48We analyzed the effect of shallow thin layers on the estimation of soil surface water content using full-waveform inversion of off-ground ground penetrating radar (GPR) data. Strong dielectric contrasts ... [more ▼]We analyzed the effect of shallow thin layers on the estimation of soil surface water content using full-waveform inversion of off-ground ground penetrating radar (GPR) data. Strong dielectric contrasts are expected to occur under fast wetting or drying weather conditions, thereby leading to constructive and destructive interferences with respect to the surface reflection. First, synthetic GPR data were generated and subsequently inverted considering different thin-layer model configurations. The resulting inversion errors when neglecting the thin layer were quantified, and then, the possibility to reconstruct these layers was investigated. Second, laboratory experiments reproducing some of the numerical experiments configurations were conducted to assess the stability of the inverse solution with respect to actual measurement and modeling errors. Results showed that neglecting shallow thin layers may lead to significant errors on the estimation of soil surface water content ($\Delta\theta$ > 0.03 $m^3/m^3$), depending on the contrast. Accounting for these layers in the inversion process strongly improved the results, although some optimization issues were encountered. In the laboratory, the proposed full-waveform method permitted to reconstruct thin layers with a high resolution up to 2 cm and to retrieve the soil surface water content with an rmse less than 0.02 $m^3/m^3$, owing to the full-waveform inverse modeling. These results suggest that the proposed GPR approach is promising for field-scale mapping of soil surface water content of nondispersive soils with low electrical conductivity and for instances when soil layering is encountered. [less ▲]Detailed reference viewed: 62 (0 ULg) Instability and Overshoots of Solutions For A Class of Homogeneous Hybrid Systems By Lyapunov-like AnalysisForni, Fulvio ; Teel, Andrewin 49th IEEE Conference on Decision and Control (cdc 2010) (2010)For a class of homogeneous hybrid systems we present a generalization to the hybrid systems framework of Chetaev's theorem and we propose a set of Lyapunov-like conditions for studying instability of the ... [more ▼]For a class of homogeneous hybrid systems we present a generalization to the hybrid systems framework of Chetaev's theorem and we propose a set of Lyapunov-like conditions for studying instability of the point x e = 0 and overshoots of solutions (namely when the norm of the solution vector x at some time instant exceeds the norm of the initial condition of x). Based on these results, we design a sum of squares algorithm that constructs a suitable Lyapunov-like function to fulfill such conditions. [less ▲]Detailed reference viewed: 17 (7 ULg) Stability For A Class of Homogeneous Hybrid Systems By Annular Lyapunov AnalysisForni, Fulvio ; Teel, Andrewin 49th IEEE Conference on Decision and Control (cdc 2010) (2010)For a class of homogeneous hybrid systems we present a set of annular Lyapunov-like conditions for inferring global pre-asymptotic stability of systems. Then, we prove that such conditions are mild ... [more ▼]For a class of homogeneous hybrid systems we present a set of annular Lyapunov-like conditions for inferring global pre-asymptotic stability of systems. Then, we prove that such conditions are mild, namely, that each globally pre-asymptotically stable system must satisfy them. Based on these results, we design a sum of squares algorithm that constructs a suitable Lyapunov-like function to fulfill such annular conditions. Finally, based on recent results on homogeneous approximations of hybrid systems, we point out that such conditions can also be used to deduce local pre-asymptotic stability for a wider class of hybrid systems. [less ▲]Detailed reference viewed: 15 (3 ULg) Gain-scheduled, model-based anti-windup for LPV systemsForni, Fulvio ; Galeani, Sergioin Automatica (2010), 46(1), 222-225The aim of this paper is to show that a recently proposed technique for anti-windup control of exponentially unstable plants can be easily extended to solve the corresponding robust anti-windup problem ... [more ▼]The aim of this paper is to show that a recently proposed technique for anti-windup control of exponentially unstable plants can be easily extended to solve the corresponding robust anti-windup problem for linear parameter varying systems, for which the time varying parameters are measured online. The proposed technique is minimally conservative with respect to the size of the resulting operating region (which coincides, up to an arbitrarily small quantity, with the largest set on which asymptotic stability can be guaranteed for the considered plant with the given saturation level and uncertainty characteristics), and is not limited to plants having only small uncertainties or being open-loop stable. [less ▲]Detailed reference viewed: 64 (6 ULg) An almost Anti-Windup scheme for plants with magnitude, rate and curvature saturationForni, Fulvio ; Galeani, Sergio; Zaccarian, ucain American Control Conference (ACC 2010) (2010)We address the anti-windup augmentation problem for plants with saturations on the magnitude, rate and curvature of the control input. To this aim, given an unconstrained closed-loop, we generate a ... [more ▼]We address the anti-windup augmentation problem for plants with saturations on the magnitude, rate and curvature of the control input. To this aim, given an unconstrained closed-loop, we generate a slightly modified strictly proper controller for which the derivatives of the control signal are available and we solve the anti-windup problem for this modified control scheme (namely, an almost anti-windup for the original closed-loop). Based on this “almost” approach, we revisit an existing Model Recovery anti-windup solution for rate and magnitude saturated plants and then we extend the results to the case of rate, magnitude and curvature saturation, by providing a Model Recovery solution to this additional problem. An example illustrates the peculiarities and the effectiveness of the proposed solutions. [less ▲]Detailed reference viewed: 22 (0 ULg) Hot and cold contrasts in high resolution Tc-99m planar scintigraphy: a survey of fifty-two camera heads using the PICKER thyroid phantomSeret, Alain in Physica Medica : An International Journal Devoted to the Applications of Physics to Medicine and Biology : Official Journal of the Italian Association of Biomedical Physics (AIFB) [=PM] (2010), 26(3), 166-172This study aimed at comparing the sensitivity and hot and cold contrasts obtained when imaging the Picker thyroid phantom using gamma cameras fitted with either their ultra-high or high-resolution low ... [more ▼]This study aimed at comparing the sensitivity and hot and cold contrasts obtained when imaging the Picker thyroid phantom using gamma cameras fitted with either their ultra-high or high-resolution low energy parallel hole collimator. Seventeen camera models from Elscint, General Electric, Siemens and Sopha Medical Vision were involved in the study for a total of 30 cameras and 52 camera heads. A single operator conducted the study in order to minimize the impact of human factors. The phantom contained about 74 MBq 99mTc and was imaged at 10-cm from the collimator face with the energy window recommended by the camera manufacturer. A total of 1 million counts were accumulated. Hot and cold contrasts were in mean about 0.05 higher when using an ultra-high-resolution than when using a high-resolution low energy collimator. This higher contrast was obtained at the expense of a mean reduction in sensitivity of 30%. In particular, Elscint cameras demonstrated a 30% lower sensitivity whatever the collimator type. The Sopha Medical Vision DST and DSX cameras and the General Electric Magicam camera offered the lowest contrasts among the cameras with a high-resolution collimator. Although this was accompanied by a higher than the mean sensitivity for the DST and DSX, the Magicam demonstrated sensitivity roughly identical to the mean of all the cameras with a high-resolution collimator. [less ▲]Detailed reference viewed: 45 (2 ULg) Synthèse bibliographique : l’écologie chimique des coccinellesDurieux, Delphine ; Verheggen, François ; Vandereycken, Axel et alin Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2010), 14(2), 351-367This paper reviews the chemical ecology of ladybird beetles (Coleoptera: Coccinellidae) to present the role of semiochemicals involved in plant-ladybird, prey-ladybird and predator-ladybird interactions ... [more ▼]This paper reviews the chemical ecology of ladybird beetles (Coleoptera: Coccinellidae) to present the role of semiochemicals involved in plant-ladybird, prey-ladybird and predator-ladybird interactions. Ladybird beetles use these compounds to locate their prey, mate, protect themselves from predation or cannibalism, find a shelter to overwinter or ensure a better survival for their offspring. Thorough studies on ladybird behaviours towards these compounds could lead to their practical implementation in integrated strategies using ladybirds to control pests, like aphids or mealybugs. [less ▲]Detailed reference viewed: 390 (75 ULg) Chilling of carcasses from double muscled cattle: time-temperature evolution and predictive modelling of growth of Listeria monocytogenes and Clostridium perfringensDelhalle, Laurent ; Collignon, Bertrand; Dehard, Sandrine et alPoster (2010)The time/temperature combination during carcass chilling is of concern in order to avoid bacterial growth. The chilling speed is lower in carcasses with high muscular development such as large cattle from ... [more ▼]The time/temperature combination during carcass chilling is of concern in order to avoid bacterial growth. The chilling speed is lower in carcasses with high muscular development such as large cattle from the Belgian Blue breed. Three slaughterhouses were selected for temperature and pH measurements during the chilling process at 6 different days on 4 half carcasses in order to obtain representative data from heavy carcasses with high muscular development. Predictive microbiology was used to evaluate the potential growth of Listeria monocytogenes and Clostridium perfringens on the surface and in the depth of the carcasses. The gamma concept was chosen as secondary model taking into account the effect of temperature, pH and water activity on the selected bacteria during the chilling process. The predicted growth potential of Listeria monocytogenes is influenced by the different environmental conditions of the selected slaughterhouses and could reach 1.4 log CFU/cm² after the chilling process. The potential growth of Clostridium perfringens is limited due to unfavourable conditions during the first hours and to low temperature later. It can be concluded that when the initial level of contaminating bacteria is not excessive the speed at which the carcass is currently chilled is sufficient to limit the growth of these two pathogens and to ensure the product quality. [less ▲]Detailed reference viewed: 52 (17 ULg)