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See detailModel Of Forest Carbon Sequestration Incorporating Aerial Wood Radiative Budget
Longdoz, B.; Aubinet, Marc ULg; François, Louis ULg

in Agricultural and Forest Meteorology (2004), 125(1-2), 83-104

The CHANCE model, simulating CO2, energy and water fluxes in a forest ecosystem, is presented. The components of the simulated canopy are the leaves, the branches, the trunks and the soil. The first three ... [more ▼]

The CHANCE model, simulating CO2, energy and water fluxes in a forest ecosystem, is presented. The components of the simulated canopy are the leaves, the branches, the trunks and the soil. The first three are divided into sunny and shaded zones. The model has been calibrated and validated in comparison with measurements performed in the temperate beech forest of Vielsalm (Belgium). For the reproduction of half-hourly net CO2 fluxes, the quality of the CHANCE results is comparable to other models (systematic error of 14%—0.51 molm−2 s−1, R2 = 0.79). The differences between simulated and measured fluxes result essentially from noise in the data, underestimation of the stomatal conductance during very dry days and heterogeneity of the south, southeast sector (presence of conifer patches). Three sensitivity tests have been performed. The first one, neglecting the contribution of aerial wood in the radiation budget, doubles the annual carbon sequestration (Seco). This trend is strengthened in the second test where common radiative and photosynthetic properties are assigned to leaves and branches. The third test induces a 30% reduction of Seco when the calculation of canopy component temperatures using the complete energy balance is replaced by the use of air temperature. © 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailModel of Irrigation Development for Floodplain of the Tonle Sap Great Lake
someth, Paradis; Kubo, n; Ly, Sarann ULg et al

Poster (2008)

Rice is a staple crop in Cambodia. To meet the large requirement of rice consumption due to rapid increased population and to boost the economy, the rice production in this country needs to be enhanced ... [more ▼]

Rice is a staple crop in Cambodia. To meet the large requirement of rice consumption due to rapid increased population and to boost the economy, the rice production in this country needs to be enhanced. The Tonle Sap Great Lake of Cambodia has huge floodplain suitable for large amount for rice production and potential water resources for rice-based farming system. Due to large variation of water level of the lake, some areas around the lake are flooded in wet season and shortage of water in dry season. Studies to exploit the flood and the water rsources of the lake and its tributaries have not been well conducted yet. The West Baray and Batheay irrigation systems are located in the floodplain of the Tonle Sap Great Lake and the Mekong River. In this research, the irrigation systems are studied as model sites for future development of the floodplain of the Tonle Sap Great Lake. [less ▲]

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See detailA Model of Lyman ë± and H[SUB]2[/SUB] Bands Excitation by Protons Precipitation in the Jovian Atmosphere
Rego, D.; Prangé; Gérard, Jean-Claude ULg

in Bulletin of the American Astronomical Society (1992, June 01)

Not Available

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See detailModel of reticuloendothelial iron metabolism in humans: abnormal behavior in idiopathic hemochromatosis and in inflammation.
Fillet, Georges ULg; Baldelli, L.; BEGUIN, Yves ULg

in Blood (1989), 74(2), 844-51

Iron transport in the reticuloendothelial (RE) system plays a central role in iron metabolism, but its regulation has not been characterized physiologically in vivo in humans. In particular, why serum ... [more ▼]

Iron transport in the reticuloendothelial (RE) system plays a central role in iron metabolism, but its regulation has not been characterized physiologically in vivo in humans. In particular, why serum iron is elevated and RE cells are much less iron-loaded than parenchymal cells in idiopathic hemochromatosis is not known. The processing of erythrocyte iron by the RE system was studied after intravenous (IV) injection of 59Fe heat-damaged RBCs (HDRBCs) and 55Fe transferrin in normal subjects and in patients with iron deficiency, idiopathic hemochromatosis, inflammation, marrow aplasia, or hyperplastic erythropoiesis. Early release of 59Fe by the RE system was calculated from the plasma iron turnover and the 59Fe plasma reappearance curve. Late release was calculated from the ratio of 59Fe/55Fe RBC utilization in 2 weeks. The partitioning of iron between the early (release from heme catabolism) and late (release from RE stores) phases depended on the size of RE iron stores, as illustrated by the inverse relationship observed between early release and plasma ferritin (P less than .001). There was a strong correlation between early release and the rate of change of serum iron levels during the first three hours in normal subjects (r = .85, P less than .001). Inflammation produced a blockade of the early release phase, whereas in idiopathic hemochromatosis early release was considerably increased as compared with subjects with similar iron stores. Based on these results, we describe a model of RE iron metabolism in humans. We conclude that the RE system appears to determine the diurnal fluctuations in serum iron levels through variations in the immediate output of heme iron. In idiopathic hemochromatosis, a defect of the RE cell in withholding iron freed from hemoglobin could be responsible for the high serum iron levels and low RE iron stores. [less ▲]

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See detailA model of spinal cord injury: the balloon-compressive model
Martin, Didier ULg; Franzen, R.; Robe, Pierre ULg et al

Conference (1995, September 03)

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See detailA model of subclinical chronic bronchitis induced by repeted nebulisations of bacterial lipopolysaccharide
Krafft, Emilie ULg; Bolognin, M.; Tual, Charlotte ULg et al

in 20th ECVIM Meeting - Toulouse - France - 9-12 septembre 2010 (2010, September 09)

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See detailModel of the algerian currents instability
Beckers, Jean-Marie ULg; Nihoul, Jacques ULg

in Journal of Marine Systems (1992), 3(4-5), 441-451

A preliminary ''small-perturbation'' analytical study of a non-dissipative idealized model of the Algerian Current is made, with the aim of identifying major characteristic scales and investigating the ... [more ▼]

A preliminary ''small-perturbation'' analytical study of a non-dissipative idealized model of the Algerian Current is made, with the aim of identifying major characteristic scales and investigating the reality of possible classical instability mechanisms. The simple configuration is shown to be stable, from a linear perturbation point of view. The GHER 3D Primitive Equation Model is then applied to a more realistic investigation of the Algerian Current. The GHER model is non-linear, three-dimensional, with turbulent closure, mode splitting and a sigma-Coordinate formulation. The numerical simulation shows the development and mature pattern of the instability in excellent agreement with the observations. The relative importance of the existence of a coastal boundary layer, the nature of the initial perturbation, baroclinic and non-linear effects on the instability mechanism is discussed. [less ▲]

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See detailModel of the Jovian magnetic field topology constrained by the Io auroral emissions
Hess, Sébastien; Bonfond, Bertrand ULg; Grodent, Denis ULg et al

Poster (2011, October)

The determination of the internal magnetic field of Jupiter has been the object of many studies and publications. These models have been computed from the Pioneer, Voyager, and Ulysses measurements. Some ... [more ▼]

The determination of the internal magnetic field of Jupiter has been the object of many studies and publications. These models have been computed from the Pioneer, Voyager, and Ulysses measurements. Some models also use the position of the Io footprints as a constraint: the magnetic field lines mapping to the footprints must have their origins along Io’s orbit. The use of this latter constraint to determine the internal magnetic field models greatly improved the modeling of the auroral emissions, in particular the radio ones, which strongly depends on the magnetic field geometry. This constraint is, however, not sufficient for allowing a completely accurate modeling. The fact that the footprint field line should map to a longitude close to Io’s was not used, so that the azimuthal component of the magnetic field could not be precisely constrained. Moreover, a recent study showed the presence of a magnetic anomaly in the northern hemisphere, which has never been included in any spherical harmonic decomposition of the internal magnetic field. We compute a decomposition of the Jovian internal magnetic field into spherical harmonics, which allows for a more accurate mapping of the magnetic field lines crossing Io, Europa, and Ganymede orbits to the satellite footprints observed in UV. This model, named VIPAL, is mostly constrained by the Io footprint positions, including the longitudinal constraint, and normalized by the Voyager and Pioneer magnetic field measurements. We show that the surface magnetic fields predicted by our model are more consistent with the observed frequencies of the Jovian radio emissions than those predicted by previous models. [less ▲]

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See detailModel of the Jovian magnetic field topology constrained by the Io auroral emissions
Hess, S.; Bonfond, Bertrand ULg; Grodent, Denis ULg et al

Poster (2011, July 11)

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See detailModel of the Jovian magnetic field topology constrained by the Io auroral emissions
Hess, S. L. G.; Bonfond, Bertrand ULg; Zarka, P. et al

in Journal of Geophysical Research. Space Physics (2011), 116

The determination of the internal magnetic field of Jupiter has been the object of many studies and publications. These models have been computed from the Pioneer, Voyager, and Ulysses measurements. Some ... [more ▼]

The determination of the internal magnetic field of Jupiter has been the object of many studies and publications. These models have been computed from the Pioneer, Voyager, and Ulysses measurements. Some models also use the position of the Io footprints as a constraint: the magnetic field lines mapping to the footprints must have their origins along Io's orbit. The use of this latter constraint to determine the internal magnetic field models greatly improved the modeling of the auroral emissions, in particular the radio ones, which strongly depends on the magnetic field geometry. This constraint is, however, not sufficient for allowing a completely accurate modeling. The fact that the footprint field line should map to a longitude close to Io's was not used, so that the azimuthal component of the magnetic field could not be precisely constrained. Moreover, a recent study showed the presence of a magnetic anomaly in the northern hemisphere, which has never been included in any spherical harmonic decomposition of the internal magnetic field. We compute a decomposition of the Jovian internal magnetic field into spherical harmonics, which allows for a more accurate mapping of the magnetic field lines crossing Io, Europa, and Ganymede orbits to the satellite footprints observed in UV. This model, named VIPAL, is mostly constrained by the Io footprint positions, including the longitudinal constraint, and normalized by the Voyager and Pioneer magnetic field measurements. We show that the surface magnetic fields predicted by our model are more consistent with the observed frequencies of the Jovian radio emissions than those predicted by previous models. [less ▲]

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See detailA model of the Lyman-alpha line profile in the proton aurora
Gérard, Jean-Claude ULg; Hubert, Benoît ULg; Bisikalo, Dimitry V et al

in Journal of Geophysical Research (2000), 105

The Lyman-alpha auroral emission is characterized by a broad line profile whose shape depends on the energy and pitch angle distributions of the initial proton beam, whereas its total brightness reflects ... [more ▼]

The Lyman-alpha auroral emission is characterized by a broad line profile whose shape depends on the energy and pitch angle distributions of the initial proton beam, whereas its total brightness reflects the proton energy flux precipitated into the auroral upper atmosphere. Global remote sensing of the proton aurora through its ultraviolet signature makes it is increasingly important to relate the characteristics of the Lyman-alpha emission to the physical properties of the precipitated proton flux. We present a numerical model of proton and hydrogen flux transport and kinetics based on the direct simulation Monte Carlo method. In this approach, all elastic and inelastic processes are stochastically simulated as well as is the production of Lyman-alpha photons with the associated Doppler velocity component. The model also includes collisional, geomagnetic, and geometric spreading of the proton-hydrogen beam. We show that consideration of the stochastic character of the H atom velocity redistribution after collisions produces line profiles different from those obtained in the strictly forward or mean scattering angle approximations previously used in proton transport codes. In particular, the predicted fraction of photons due to backscattered particles is considerably larger when stochastic collision scattering is considered than in the strictly forward or mean scattering angle approximations. In contrast to the median wavelength, the position of the peak in the line profile shows a weak inverse dependence on the proton energy. The efficiency of the Lyman-alpha photon production per unit incident energy flux significantly drops as the mean proton energy increases. The line profile and the amount of blue-shifted (for downward viewing) emission depends in a complex way on the initial energy and pitch angle distribution of the protons. The line profiles expected for the noon cusp and midnight proton aurora are shown to be significantly different. [less ▲]

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See detailA model of the seasonal dynamics of biomass and production of the seagrass Posidonia oceanica in the Bay of Calvi (Northwestern Mediterranean)
Elkalay, Khalid; Frangoulis, Constantin; Skliris, Nikolaos ULg et al

in Ecological Modelling (2003), 167(1-2), 1-18

Modelling of seagrasses can be an effective tool to assess factors regulating their growth. Growth and production model of Posidonia oceanica, the dominant submerged aquatic macrophyte occurring in the ... [more ▼]

Modelling of seagrasses can be an effective tool to assess factors regulating their growth. Growth and production model of Posidonia oceanica, the dominant submerged aquatic macrophyte occurring in the Bay of Calvi (Corsica, Ligurian Sea, Northwestern (NW) Mediterranean) was developed. The state variables are the above- and below-ground biomass of P oceanica, the epiphyte biomass, and the internal nitrogen concentration of the whole plant. Light intensity and water temperature are the forcing variables. The model reproduces successfully seasonal growth and production for each variable at various depths (10, 20 and 30 m). The model can simulate also a number of consecutive years. Sensitivity analysis of model's parameters showed that the maximum nitrogen quota n(max) rate is the most sensitive parameter in this model. The results simulations imply that light intensity is one of the most important abiotic factors, the diminution of which can cause an important reduction in seagrass density. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailThe model of thymic cryptocrine cell-to-cell signaling in developmental immunology
Geenen, Vincent ULg

Conference given outside the academic context (1992)

Detailed reference viewed: 27 (0 ULg)
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See detailModel order reduction techniques for thermomechanical systems with nonlinear radiative heat transfer using proper orthogonal decomposition
Hickey, Daryl ULg; Hoffait, Sébastien ULg; Rothkegel Ide, José Ignacio ULg et al

in Proceedings of ISMA 2010 (2010, September)

Analysing large scale, nonlinear, multiphysical, dynamical structures, by using mathematical modelling and simulation, e.g. Finite Element Modelling (FEM), can be computationally very expensive ... [more ▼]

Analysing large scale, nonlinear, multiphysical, dynamical structures, by using mathematical modelling and simulation, e.g. Finite Element Modelling (FEM), can be computationally very expensive, especially if the number of degrees-of-freedom is high. This paper develops modal reduction techniques for such nonlinear multiphysical systems. The paper focuses on Proper Orthogonal Decomposition (POD), a multivariate statistical method that obtains a compact representation of a data set by reducing a large number of interdependent variables to a much smaller number of uncorrelated variables. A fully coupled, thermomechanical model consisting of a multilayered, cantilever beam is described and analysed. This linear benchmark beam is then extended to incorporate an external box. The nonlinear radiative exchanges between the beam and the external box are analysed and a reduction procedure is proposed for this fully coupled, nonlinear, multiphysical, thermomechanical system. Two alternative approaches to the reduction are investigated, a monolithic scaled approach and a partitioned approach that treats the individual physical modes separately. [less ▲]

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See detailModel physical parameters effects on real solar cell characteristics and power curve
Aazou, Safae ULg; ASSAID, El Mahdi

in Global Journal of Physical Chemistry (2011), 2(2), 61-67

The climate change crisis and the running out of fossil resources are motivating the use of renewable energies. Solar energy is the main source of the renewable energies and photovoltaics is one of the ... [more ▼]

The climate change crisis and the running out of fossil resources are motivating the use of renewable energies. Solar energy is the main source of the renewable energies and photovoltaics is one of the main ways of photon conversion. This alternative energy is safe, clean and abundant. The purpose of this paper is the use of Maple software in: - Determining, without any approximation, the model physical parameters of real photovoltaic solar cell as a basic element of photovoltaic conversion. - Analyzing the effects of each physical parameter on real solar cell current-voltage characteristics and output power curve. [less ▲]

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See detailModel predictive control and reinforcement learning as two complementary frameworks
Ernst, Damien ULg; Glavic, Mevludin; Capitanescu, Florin ULg et al

in International Journal of Tomography & Statistics (2007), 6

Model predictive control (MPC) and reinforcement learning (RL) are two popular families of methods to control system dynamics. In their traditional setting, they formulate the control problem as a ... [more ▼]

Model predictive control (MPC) and reinforcement learning (RL) are two popular families of methods to control system dynamics. In their traditional setting, they formulate the control problem as a discrete-time optimal control problem and compute a suboptimal control policy. We present in this paper in a unified framework these two families of methods. We run for MPC and RL algorithms simulations on a benchmark control problem taken from the power system literature and discuss the results obtained. [less ▲]

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See detailModel predictive control and reinforcement learning as two complementary frameworks
Ernst, Damien ULg; Glavic, Mevludin; Capitanescu, Florin ULg et al

in Proceedings of the 13th IFAC Workshop on Control Applications of Optimisation (2006)

Model predictive control (MPC) and reinforcement learning (RL) are two popular families of methods to control system dynamics. In their traditional setting, they formulate the control problem as a ... [more ▼]

Model predictive control (MPC) and reinforcement learning (RL) are two popular families of methods to control system dynamics. In their traditional setting, they formulate the control problem as a discrete-time optimal control problem and compute a suboptimal control policy. We present in this paper in a unified framework these two families of methods. We run for MPC and RL algorithms simulations on a benchmark control problem taken from the power system literature and discuss the results obtained. [less ▲]

Detailed reference viewed: 107 (6 ULg)