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See detailL'estimation du volume de peuplements de hêtres au moyen de tarifs de cubage de peuplements.K
Fagot, Jean; Lecomte, Hugues; Rondeux, Jacques ULg

in Bulletin de la Société Royale Forestière de Belgique = Tijdschrift van de Koninklijke Belgische Bosbouwmaatschappij (1984), 91e année(6), 221-229

Various types of stand volume tables have been constructed for beech stands (Fagus sylvatica L.) in the southern part of Belgium. Volumes per hectare are calculated to 10 specified top girths. They are ... [more ▼]

Various types of stand volume tables have been constructed for beech stands (Fagus sylvatica L.) in the southern part of Belgium. Volumes per hectare are calculated to 10 specified top girths. They are based upon basal area and top height. [less ▲]

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See detailEstimation from cross-sectional data under a semiparametric truncation model
de Uña-Álvarez, Jacobo; Heuchenne, Cédric ULg; Laurent, Géraldine ULg

E-print/Working paper (2013)

Cross-sectional sampling is often used when investigating inter-event times, resulting in left-truncated and right-censored data. In this paper we consider a semiparametric truncation model in which the ... [more ▼]

Cross-sectional sampling is often used when investigating inter-event times, resulting in left-truncated and right-censored data. In this paper we consider a semiparametric truncation model in which the truncating variable is assumed to belong to a certain parametric family, while nothing is assumed on lifetime and censoring distributions. The novelty of this work is in the fact that it introduces estimators of this semiparametric model in the presence of censoring. Two alternative methods are considered, based on conditional and full likelihood considerations. Asymptotic representations of the estimators for the lifetime distribution are obtained, and their weak convergence is established. The finite sample performance of the new estimators is explored through simulations, and two real data illustrations are provided. One of the conclusions of our research is that both estimators perform better than Wang's NPMLE when the parametric family for the truncation variable is valid) in the sense of the integrated mean squared error, and that the full likelihood approach is preferable to the conditional likelihood approach for the estimation of the lifetime distribution but not necessarily for the estimation of the truncation distribution. [less ▲]

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See detailEstimation in censored linear regression via preliminary smoothing
Heuchenne, Cédric ULg; Van Keilegom, Ingrid

in Bulletin of the International Statistical Institute, 54th Session (2003)

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See detailEstimation in nonparametric location-scale regression models with censored data
Heuchenne, Cédric ULg; Van Keilegom, Ingrid

in Annals of the Institute of Statistical Mathematics (2010), 62

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See detailEstimation Monte Carlo sans modèle de politiques de décision
Fonteneau, Raphaël ULg; Murphy, Susan A.; Wehenkel, Louis ULg et al

in Revue d'Intelligence Artificielle [=RIA] (2011), 25

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See detailEstimation non-paramétrique de l'intensité d'un processus de Poisson.
Charles, Catherine ULg; Rasson, Jean-Paul

in GRETSI'01 (2001)

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See detailEstimation of inbreeding rates and extinction risk of forty one Belgian chicken breeds in 2005 and 2010
Moula, Nassim ULg; Philippe, François-Xavier ULg; Antoine-Moussiaux, Nicolas ULg et al

in Archivos de zootecnia (2014), 63(2),

In Belgium, as generally in Europe, the dominant position of the high producing commercial strains specialized in meat or eggs production threats of extinction the local traditional breeds. In this work ... [more ▼]

In Belgium, as generally in Europe, the dominant position of the high producing commercial strains specialized in meat or eggs production threats of extinction the local traditional breeds. In this work, a follow up of the changes in populations size, and the rates of inbreeding of the Belgian poultry breeds, has been carried out in 2005 and 2010. About forty breeds were concerned. The Belgian hen breeds being overwhelmingly under threat of extinction, because of the low number of individuals by breed. For each of these breeds, various criteria were considered, risk status, breeding male to breeding female ratio, effective population size, effective population size to actual size ratio and rate of inbreeding. [less ▲]

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See detailEstimation of (co)variance components across breeds by a test-day model adapted to New Zealand dairy cattle.
Vanderick, Sylvie ULg; Harris, Bevin; Mayeres, Patrick et al

in Proceedings of the British Society of Animal Science (2005)

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See detailEstimation of (co)variance components across breeds by a test-day model adapted to New Zealand dairy cattle.
Vanderick, Sylvie ULg; Harris, Bevin; Mayeres, Patrick et al

Poster (2005)

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See detailEstimation of (co)variance components for Jersey type traits using a repeatability model
Gengler, Nicolas ULg; Wiggans, G. R.; Wright, J. R. et al

in Journal of Dairy Science (1997), 80(8), 1801-1806

(Co)variance components for final score and 15 linear type traits of Jersey cows were estimated by multitrait REML using multiple diagonalization and a repeatability model with 34,999 records of 22,354 ... [more ▼]

(Co)variance components for final score and 15 linear type traits of Jersey cows were estimated by multitrait REML using multiple diagonalization and a repeatability model with 34,999 records of 22,354 cows. Multiple diagonalization gave relative off-diagonals (ratio of squared off-diagonals to the product of diagonals) of <0.1%. Heritabilities and repeatabilities, respectively, were estimated as 0.29 and 0.48 for final score, 0.40 and 0.57 for stature, 0.26 and 0.39 for strength, 0.28 and 0.43 for dairy form, 0.13 and 0.25 for foot angle, 0.13 and 0.25 for rear legs (side view), 0.27 and 0.41 for body depth, 0.31 and 0.52 for rump angle, 0.22 and 0.33 for thurl width, 0.22 and 0.36 for fore udder attachment, 0.28 and 0.46 for rear udder height, 0.26 and 0.42 for rear udder width, 0.32 and 0.48 for udder depth, 0.20 and 0.36 for udder cleft, 0.29 and 0.46 for front teat placement, and 0.31 and 0.48 for teat length. Estimates of heritability generally were higher, and estimates of repeatability were lower, than values used previously for USDA genetic evaluations, which were based on data from the 1970s and early 1980s. Final score was highly correlated both genetically and phenotypically with dairy form and rear udder traits. These estimates of heritabilities and (co)variance components are necessary for multitrait genetic evaluation of linear type traits of US Jerseys. [less ▲]

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See detailEstimation of (co)variance function coefficients for test day yield with a expectation-maximization restricted maximum likelihood algorithm
Gengler, Nicolas ULg; Tijani, A.; Wiggans, G. R. et al

in Journal of Dairy Science (1999), 82(8), 18491-184923

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See detailEstimation of (co)variance functions for test-day yields during first and second lactations in the United States
Gengler, Nicolas ULg; Tijani, A.; Wiggans, G. R. et al

in Journal of Dairy Science (2001), 82

(Co)variance components for milk, fat, and protein yields during first and second lactations were estimated from test-day data from 23,029 Holstein cows from 37 herds in Pennsylvania and Wisconsin using a ... [more ▼]

(Co)variance components for milk, fat, and protein yields during first and second lactations were estimated from test-day data from 23,029 Holstein cows from 37 herds in Pennsylvania and Wisconsin using a multitrait test-day model. Canonical transformation was used with an expectation-maximization algorithm. To allow description of (co)variances within and across yield traits and parities, four lactation stages of 75 d were defined6 for each parity, and the test day nearest the center of each interval was used. Prior to analysis, data were adjusted for lactation curves within lactation stages using all records from all available cows. Data from cows with missing values were excluded to allow a canonical transformation to be used for estimation of (co)variance matrices. Data from 9110 cows were available for canonical analysis of lactations with test days in all lactation stages. (Co)variance functions were used to describe (co)variance structure within and across yield trait and parity. (Co)variance components of biological functions (305-d yield, persistency defined as difference between yields on d 280 and 60, and maturity rate defined as difference between second- and first-lactation yields) were developed from (co)variance functions. Heritabilities ranged from 0.09 to 0.22 for test-day yields, from 0.21 to 0.23 for 305-d yields, from 0.03 to 0.11 for persistencies, and from 0.05 to 0.07 for maturity rates. Phenotypic correlations between first- and second-lactation persistencies were low, but genetic correlations were high. Genetic correlations with maturity rate ranged from 0.11 to 0.61 for 305-d yields and persistencies. [less ▲]

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See detailEstimation of (co)variances of test day yields for first lactation Holsteins in the United States
Gengler, Nicolas ULg; Tijani, A.; Wiggans, G. R. et al

in Journal of Dairy Science (1999), 82(1), 2251-22514

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See detailEstimation of a general parametric location in censored regression
Heuchenne, Cédric ULg; Van Keilegom, Ingrid

in Exploring research frontiers in contemporary statistics and econometrics - A Festschrift for Léopold Simar (2012)

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See detailEstimation of actual evapotranspiration at large watershed scale in Africa using NOAA-AVHRR surface temperature and NDVI.
Touré, Souleymane; Tychon, Bernard ULg

in 1997 Meteorological satellite data users' conference Proceedings (1997)

To estimate actual evapotranspiration on regional scale, seven subcatchments were choosen on fleuve Niger catchment where we have selected stations for representative meteorological measurements ... [more ▼]

To estimate actual evapotranspiration on regional scale, seven subcatchments were choosen on fleuve Niger catchment where we have selected stations for representative meteorological measurements. Precipitation values are spatially represented by using Thiessen polygons and Kriging methods and, based on water balance equation, we deduce the actual evapotranspiration term.The goal (objective) of this study is to deduce from the water balance equation the evapotranspiration term, to correlate remote sensing indicators (surface temperature and NDVI) and evapotranspiration data and characterise factors that affect this correlation. [less ▲]

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See detailEstimation of additive and dominance genetic variances with Method R
Druet, Tom ULg

Doctoral thesis (2002)

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See detailEstimation of additive and nonadditive genetic variances in Hereford, Gelbvieh, and Charolais by Method R.
Duangjinda, M.; Bertrand, K.; Misztal, I. et al

in Journal of Animal Science (2001), 79(12), 2997-3001

Parameters for direct and maternal dominance were estimated in models that included non-additive genetic effects. The analyses used weaning weight records adjusted for age of dam from populations of ... [more ▼]

Parameters for direct and maternal dominance were estimated in models that included non-additive genetic effects. The analyses used weaning weight records adjusted for age of dam from populations of Canadian Hereford (n = 467,814), American Gelbvieh (n = 501,552), and American Charolais (n = 314,552). Method R estimates of direct additive genetic, maternal additive genetic, permanent maternal environment, direct dominance, and maternal dominance variances as a proportion of the total variance were 23, 12, 13, 19, and 14% in Hereford; 27, 7, 10, 18, and 2% in Gelbvieh; and 34, 15, 15, 23, and 2% in Charolais. The correlations between direct and maternal additive genetic effects were -0.30, -0.23, and -0.47 in Hereford, Gelbvieh, and Charolais, respectively. The correlations between direct and maternal dominance were -0.38, -0.02, and -0.04 in Hereford, Gelbvieh, and Charolais, respectively. Estimates of inbreeding depression were -0.20, -0.18, and -0.13 kg per 1% of inbreeding for Hereford, Gelbvieh, and Charolais, respectively. Estimates of the maternal inbreeding depression were -0.01, -0.02, and -0.02 kg, respectively. The high ratio of direct dominance to additive genetic variances provided some evidence that direct dominance effects should be considered in beef cattle evaluation. However, maternal dominance effects seemed to be important only for Hereford cattle. [less ▲]

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See detailEstimation of air quality degradation due to Saharan dust at Nouakchott, Mauritania, from horizontal visibility data
Ozer, Pierre ULg; Laghdaf, MBOM; Lemine, S. O. M. et al

in Water, Air & Soil Pollution (2007), 178(1-4), 79-87

It is now irrefutable that air pollution caused by large amounts of Total Suspended Particulates (TSP) and respiratory particulates or Particulate Matter less than 10 mu m in aerodynamic diameter (PM10 ... [more ▼]

It is now irrefutable that air pollution caused by large amounts of Total Suspended Particulates (TSP) and respiratory particulates or Particulate Matter less than 10 mu m in aerodynamic diameter (PM10) has numerous undesired consequences on human health. Air quality degradation far from the African continent, in the US and in Europe, caused by high concentrations of African dust, is seen as a major threat even though most of these countries are very distant from the Sahara. Surprisingly, no estimates of TSP or PM10 levels near the Saharan dust source are available. Based on horizontal visibility observations which are reduced by the presence of dust in the atmosphere, TSP and PM10 levels are estimated throughout the year 2000 at Nouakchott-Airport, Mauritania, using relations found in the literature. It appears that concentrations of particles are significant both in terms magnitude and frequency, as the 24-hour PM10 thresholds established by the US EPA National Ambient Air Quality Standards and the EU Limits Values for Air Quality were exceeded 86 and 137 times, respectively. The average annual concentration is far above air quality standards and estimated at 159 mu g m(-3) for TSP and 108 mu g m(-3) for PM10. These very high particulate levels are likely to represent an important public health hazard and should be considered as a major environmental risk. [less ▲]

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