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Peer Reviewed
See detailEstimation of joint contact forces in the equine digit
Noble, Prisca ULg; Collin, Bernard ULg; Denoix, Jean-Marie et al

in ISB proceedings (2009, July)

Detailed reference viewed: 109 (29 ULg)
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See detailEstimation of latent heat fluxes with a modified Jackson model applied to sparse vegetation : application to the hapex Sahel experiment
Tychon, Bernard ULg; Wollenweber, Gabriele

in Demarée, G.; Alexandre, J.; De Dapper, M. (Eds.) Proceedings of the International conference "Tropical climatology, meteorology and hydrology. In memoriam Franz Bultot" Brussels, 22-24 May, 1996 (1998)

The Jackson Model allows to estimate daily actual evaporation from the integrated daily net radiation and from the difference between surface temperature and air near-midday. Accepting a few assumptions ... [more ▼]

The Jackson Model allows to estimate daily actual evaporation from the integrated daily net radiation and from the difference between surface temperature and air near-midday. Accepting a few assumptions and after mathematical manipulations of the initial model, the daily evapotranspiration can be obtained if the near-midday instantaneous sensible heat fluxes and the daily and near midday net radiation are known. This paper focus on the estimation of the instantaneous sensible heat fluxes. Two approaches are used to estimate them : the first uses a classical approach which represents the surface with a homogeneous single layer. The second model approximates the surface with a double-layer. In the latter model, one layer represents the soil and herbaceous vegetation while the second layer is assumed to represent the foliage of trees or shrubs (high vegetation) depending on the site. Finally, this double-layer model is simplified to allow its use by remote sensors observations. These three models are compared with field measurements during the Hapex-Sahel 92 experiment in Niger. The results show that the classical one-layer model is unable to express the latent heat fluxes of this sparse vegetation while the two double-layer models appear promising and need further developments. [less ▲]

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See detailEstimation of modal correlation coefficients from background and resonant responses
Denoël, Vincent ULg

in Structural Engineering and Mechanics: an International Journal (2009), 32(6), 725-740

A new simple relation for the estimation of modal correlation coefficients is presented. It is obtained from the decomposition of covariances of modal responses into background and resonant contributions ... [more ▼]

A new simple relation for the estimation of modal correlation coefficients is presented. It is obtained from the decomposition of covariances of modal responses into background and resonant contributions, as it is commonly done for the variances. Thanks to appropriate assumptions, the modal correlation coefficients are estimated as weighted sums of two limit values, corresponding to the background and resonant responses respectively. The weighting coefficients are expressed as functions of the background-to-resonant ratios, which makes the proposed formulation convenient and easily accessible. The simplicity of the mathematical formulation facilitates the physical interpretation. It is for example proved that modal correlation coefficients can be non negligable even in case of well separated natural frequencies, which is sometimes unclear in the litterature. The new relation is mainly efficient in case of large finite element models. It is applied and validated on a finite element buffeting analysis of the Viaduct of Millau, the highest bridge deck ever built so far. [less ▲]

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See detailEstimation of Myostatin gene effects on production traits and fatty acid contents in bovine milk
Vanrobays, Marie-Laure ULg; Bastin, Catherine ULg; Colinet, Frédéric ULg et al

in Book of Abstracts of the 63rd Annual Meeting of the European Federation of Animal Science (2012, August)

Detailed reference viewed: 25 (5 ULg)
See detailEstimation of non-additive genetic variances and maternal inbreeding depression in Canadian Herefords
Duangjinda, M.; Druet, Tom ULg; Misztal, I. et al

in Abstracts from the 2000 ADSA/ASAS joint annual meeting (2000)

Detailed reference viewed: 11 (2 ULg)
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See detailEstimation of odor emission rate from landfill areas using the sniffing team method
Nicolas, Jacques ULg; Craffe, Flavien; Romain, Anne-Claude ULg

in Waste Management (2006), 26(11), 1259-1269

The monitoring of the odor annoyance generated by a landfill area is difficult, since it is a multi-area-sources problem, with a discontinuous odor emission. This paper proposes an adaptation of the ... [more ▼]

The monitoring of the odor annoyance generated by a landfill area is difficult, since it is a multi-area-sources problem, with a discontinuous odor emission. This paper proposes an adaptation of the method of sniffing team campaigns to the particular case of fresh waste odors. The method is based on the field determination of odor perception points, followed by data processing with a bi-Gaussian-type model, adapted to handle the odors. In a first step, field observers delineate the region in which odor impact is experienced and then the emission rate is manipulated in a dispersion model until the predicted size of the impact zone matches that observed in the field. In a second step the adjusted emission rate is entered into the model to calculate the percentiles corresponding to the average annoyance zone. The originality of the proposed method is the introduction of all observation points and of all recorded meteorological data into the model. The paper discusses the method limitations and the errors induced on the results, i.e. the odor emission rate and the percentile lines (or iso-concentration lines) which are used to describe the odor concentrations on a map of the surroundings of the plant.The proposed method proves to be reliable for diffuse sources, such as landfill areas. The obtained results are coherent with other results found in the literature with other techniques. [less ▲]

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See detailEstimation of phenotypic and genetic parameters for weight gain and weight at fixed ages in the double-muscled Belgian Blue Beef breed using field records
Coopman, F.; Krafft, A.; Dewulf, J. et al

in Journal of Animal Breeding & Genetics (2007), 124(1), 20-25

In the double-muscled Belgian Blue beef (DM-BBB) breed, selection focuses on muscular conformation and not on weight gain and higher weight. There are very few studies on growth in the DM-BBB using field ... [more ▼]

In the double-muscled Belgian Blue beef (DM-BBB) breed, selection focuses on muscular conformation and not on weight gain and higher weight. There are very few studies on growth in the DM-BBB using field records. Therefore, farms have no available useful figures on weight at fixed ages and weight gain for the DM-BBB. This study describes and evaluates live weights of DM-BBB animals. All the data were gathered on farms in Belgium. It was found that a male DM-BBB weighs an average of 51 kg at birth, 98 kg at 3 months, 242 kg at 7 months, 430 kg at 13 months and 627 kg at 20 months. Between the age of 7 and 20 months, weight gain is more than 1200 g a day. Females weigh 47 kg at birth, 96 kg at 3 months, 189 kg at 7 months and 332 kg at 13 months. For males, estimates of heritability for weights at 7, 13 and 20 months were between 0.21 and 0.36. The heritability for weight gain between 13 and 20 months was 0.13. This demonstrates that it is possible to select for higher weights and for increased growth between 13 and 20 months. Animals having high weights at a young age (7 and 13 months) tend to have also high weight at slaughtering age (20 months; r(g) between 0.81 and 0.98), but no additional growth between 13 and 20 months (r(g) between -0.09 and 0.00). High weight at 20 months is partially due to growth between 13 and 20 months (r(g) = 0.49). [less ▲]

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See detailEstimation of renal function in anorexia nervosa
Delanaye, Pierre ULg; Radermecker, Régis ULg; Saint-Remy, Annie ULg et al

in Kidney International (2004)

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See detailEstimation of rotor angles of synchronous machines using artificial neural networks and local PMU-based quantities
Del Angel, A.; Geurts, Pierre ULg; Ernst, Damien ULg et al

in Neurocomputing (2007), 70(16-18), 2668-2678

This paper investigates a possibility for estimating rotor angles in the time frame of transient (angle) stability of electric power systems, for use in real-time. The proposed dynamic state estimation ... [more ▼]

This paper investigates a possibility for estimating rotor angles in the time frame of transient (angle) stability of electric power systems, for use in real-time. The proposed dynamic state estimation technique is based on the use of voltage and current phasors obtained from a phasor measurement unit supposed to be installed on the extra-high voltage side of the substation of a power plant, together with a multilayer perceptron trained off-line from simulations. We demonstrate that an intuitive approach to directly map phasor measurement inputs to the neural network to generator rotor angle does not offer satisfactory results. We found out that a good way to approach the angle estimation problem is to use two neural networks in order to estimate the sin(delta) and cos(delta) of the angle and recover the latter from these values by simple post-processing. Simulation results on a part of the Mexican interconnected system show that the approach could yield satisfactory accuracy for realtime monitoring and control of transient instability. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]

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See detailEstimation of rubber sliding friction from asperity interaction modeling
Bui, Q. V.; Ponthot, Jean-Philippe ULg

in Wear (2002), 252(1-2), 150-160

Interaction between a soft rubber asperity and its hard counterpart is traced with the help of a finite element computation. The analysis is aimed to estimate the influence of adhesion between rubber and ... [more ▼]

Interaction between a soft rubber asperity and its hard counterpart is traced with the help of a finite element computation. The analysis is aimed to estimate the influence of adhesion between rubber and rigid surfaces and the energy losses arising from the deformation of rubber bulk to the sliding resistance. At the contact zone, interfacial bonds are formed due to adhesion and their resistance to sliding is represented by the shear strength of the contact interface. In the rubber bulk, the hysteresis loss is calculated using an appropriate model of the viscoelastic mechanical behavior of rubber for large strains. Dependence of friction on sliding speeds and temperature is hence detected. Influence of surface roughness and contact pressure on friction is also examined. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

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See detailEstimation of sarcopenia prevalence using various assessment tools
Beaudart, Charlotte ULg; Reginster, Jean-Yves ULg; Slomian, Justine ULg et al

in Experimental Gerontology (2014), 61

BACKGROUND: Sarcopenia is defined as a progressive and generalized loss of muscle mass with either a loss of muscle strength or a loss of physical performance but there is no recommendation regarding the ... [more ▼]

BACKGROUND: Sarcopenia is defined as a progressive and generalized loss of muscle mass with either a loss of muscle strength or a loss of physical performance but there is no recommendation regarding the diagnostic tools that have to be used. In this study, we compared the prevalence of sarcopenia assessed using different diagnostic tools. METHODS: To measure muscle mass, muscle strength and physical performance, we used for each outcome two different diagnostic tools. For muscle mass, we used Dual Energy X-Ray Absorptiometry (DXA) and bio-electrical impedance analysis (BIA); for muscle strength, we used a hydraulic dynamometer and a pneumatic dynamometer; for physical performance we used the Short Physical Performance Battery test (SPPB test) and the walk speed. Eight diagnostic groups were hereby established. RESULTS: A total of 250 consecutive subjects were recruited in an outpatient clinic in Liège, Belgium. Estimated prevalence of sarcopenia varied from 8.4% to 27.6% depending on the method of diagnosis used. Regarding muscle mass, BIA systematically overestimated muscle mass compared to DXA (mean estimated prevalence with BIA=12.8%; mean prevalence with DXA=21%). For muscle strength, the pneumatic dynamometer diagnosed twice more sarcopenic subjects than the hydraulic dynamometer (mean estimated prevalence with PD=22.4%; mean estimated prevalence with HD=11.4%). Finally, no difference in prevalence was observed when the walking speed or the SPPB test was used. A weak overall kappa coefficient was observed (0.53), suggesting that the 8 methods of diagnosis are moderately concordant. CONCLUSION: Within the same definition of sarcopenia, prevalence of sarcopenia is highly dependent on the diagnostic tools used. [less ▲]

Detailed reference viewed: 31 (15 ULg)
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See detailEstimation of sediment storage in Ardenne's floodplains (Belgium) during the last centuries
Houbrechts, Geoffrey ULg; Mols, Julien; Petit, François ULg

Conference (2007)

Estimation of the sediment storage in floodplains is the focus of several researchers. One of the main difficulties is to date alluvial deposits which do not contain organic matters or which are more ... [more ▼]

Estimation of the sediment storage in floodplains is the focus of several researchers. One of the main difficulties is to date alluvial deposits which do not contain organic matters or which are more recent than 200 BP. Consequently, we developed a relative dating method, based on the presence of iron slag. These residues have been produced since the end of the 14th century by the former metal works located near rivers of the Ardenne region. In order to use slag as a stratigraphical tracer, we dated the periods of furnace activity from historical studies and we analysed vertical slag concentration in alluvial silty deposits. These data allowed us to reconstruct the topography of several floodplains at the inception of the metal works, to evaluate sedimentation rates and to estimate lateral channel mobility. Given important deforestations due to the production of charcoal for the iron metallurgy, we observed an increase of the sedimentation rates during the last centuries. [less ▲]

Detailed reference viewed: 4 (0 ULg)
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See detailEstimation of shortening rate since late Pleistocene in the Aksu area on the southern flank of the Tianshan
Wang, X.; Jia, C. Z.; Hubert, Aurelia ULg et al

in Science in China. Series D : Earth Sciences (2001), 44

Detailed reference viewed: 4 (0 ULg)
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See detailEstimation of surface soil organic matter by means of hyperspectral data analysis.
Touré, Souleymane; Tychon, Bernard ULg

Conference (2003, September 04)

This presentation shows results from two different hyperspectral instruments for the assessment of soil organic content of agricultural soils in southern Belgium.

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See detailEstimation of surface soil organic matter by means of hyperspectral data analysis.
Touré, Souleymane; Tychon, Bernard ULg

Conference (2003, November 19)

Data acquired from field campaign and hyperspectral airborne sensors were processed to determine the surface soil organic matter of an agricultural area located in Southern Belgium. The method adopted was ... [more ▼]

Data acquired from field campaign and hyperspectral airborne sensors were processed to determine the surface soil organic matter of an agricultural area located in Southern Belgium. The method adopted was based on a forward stepwise multiple regression analysis linking soil organic matter and hyperspectral data from two airborne sensors working in the visible and infrared domain. The results were validated successfully from an independent set of sampling points. It is concluded that the hyperspectral remote sensing approach is promising for soil organic matter prediction. Furthermore, this approach could even be improved if disturbance factors are removed. [less ▲]

Detailed reference viewed: 12 (2 ULg)
Peer Reviewed
See detailEstimation of temporal lags for the inference of gene regulatory networks from time series (inproceedings) Author
Lopes, Miguel; Meyer, Patrick ULg; Bontempi, Gianluca

in In proceedings of BENELEARN'12 (2012)

Detailed reference viewed: 21 (3 ULg)