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See detailAssessing heat stress effects on production traits of Holsteins in a temperate region
Hammami, Hedi ULg; Bormann, Jeanne; Gengler, Nicolas ULg

in Book of abstracts of the 63rd Annual Meeting of the European Association for Animal Production (2012)

Heat stress impaired productive, reproductive and animal behaviour. Examination of milk production loss due to heat stress was mainly evaluated in USA and few tropical countries using the temperature ... [more ▼]

Heat stress impaired productive, reproductive and animal behaviour. Examination of milk production loss due to heat stress was mainly evaluated in USA and few tropical countries using the temperature humidity index (THI1) developed in the 1950’s. The main objective of this study was to evaluate the effects of six new environmental stress indices on production traits in a temperate region. These indices include solar radiation and wind speed in addition to the temperature and humidity only defining THI1. For that purpose, 530820 milk, fat, protein, and somatic cell count first-lactation test-day records (TD) collected between 2000 and 2011 in Luxembourg were used. TD records were merged with meteorological data from 14 public weather stations. Each TD was assigned to the average daily thermal index of the 3 days before. Firstly, broken-line regression models were applied to identify the threshold of heat stress (THR) for each of the thermal indices. The decline of daily production of the different traits above THR point was assessed by mixed linear models including regression on unit of each of the thermal index. Estimates of THR were specific to each thermal index and trait. Significant decrease of milk, fat and protein yields above THR was observed for all studied thermal predictors. Whereas, an increase of the somatic cell score was observed above the specific THR point. THR estimates for THI1 and THI6 were of 68 and 80 and 62 and 78 for milk and protein yields respectively. Respective rate of decline per unit were of 0.243 and 0.188 kg and 0.0045 and 0.0051 kg respectively. Results from this phenotypic analysis show that evaluating heat tolerance based on bio-meteorological indicators is promising and phenotypic and genetic implications should be investigated. [less ▲]

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See detailAssessing heat tracing experiment data sets for direct forecast of temperature evolution in subsurface models: an example of well and geophysical monitoring data
Hermans, Thomas ULg; Oware, Erasmus; Klepikova, Maria et al

Scientific conference (2016, May 04)

Hydrogeological inverse modeling is used for integrating data and calibrating subsurface model parameters. On one hand, deterministic approaches are relatively fast but fail to catch the uncertainty ... [more ▼]

Hydrogeological inverse modeling is used for integrating data and calibrating subsurface model parameters. On one hand, deterministic approaches are relatively fast but fail to catch the uncertainty related to the spatial distribution of model parameters. On the other hand, stochastic inverse modeling is time-consuming and sampling the full high-dimensional parameter space is generally impossible. Even then, the end result is not the inverted model itself, but the forecast built from such models. In this study, we investigate a prediction-focused approach (PFA) in order to derive a direct statistical relationship between data and forecast without explicitly calibrating any models to the data. To derive this relationship, we first sample a limited number of models from the prior distribution using geostatistical methods. For each model, we then apply two forward simulations: the first corresponds to the forward model of the data (past), the second corresponds to the forward model of the forecast (future). The relationship between observed data and forecast is generally highly non-linear, depending on the complexity of the prior distribution and the differences in the two forward operators. In order to derive a useful relationship, we first reduce the dimension of the data and the forecast through principal component analysis (PCA) related techniques in order to keep the most informative part of both sets. Then, we apply canonical correlation analysis (CCA) to establish a linear relationship between data and forecast in the reduced space components. If such a relationship exists, it is possible to directly sample the posterior distribution of the forecast with a multi-Gaussian framework. In this study, we apply this methodology to forecast the evolution with time of the distribution of temperature in a control panel in an alluvial aquifer. We simulate a heat tracing experiment monitored with both well logging probes and electrical resistivity tomography. We show (1) that the proposed method can be used to quantify the uncertainty on the forecast both spatially and temporally and (2) that spatially-distributed data acquired through geophysical methods help to significantly reduce the uncertainty of the posterior. [less ▲]

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See detailAssessing heat tracing experiment data sets for direct forecast of temperature evolution in subsurface models: an example of well and geophysical monitoring data
Hermans, Thomas ULg; Klepikova, Maria; Caers, Jef

Conference (2016, April 21)

Hydrogeological inverse modeling is used for integrating data and calibrating subsurface model parameters. On one hand, deterministic approaches are relatively fast but fail to catch the uncertainty ... [more ▼]

Hydrogeological inverse modeling is used for integrating data and calibrating subsurface model parameters. On one hand, deterministic approaches are relatively fast but fail to catch the uncertainty related to the spatial distribution of model parameters. On the other hand, stochastic inverse modeling is time-consuming and sampling the full high-dimensional parameter space is generally impossible. Even then, the end result is not the inverted model itself, but the forecast built from such models. In this study, we investigate a prediction-focused approach (PFA) in order to derive a direct statistical relationship between data and forecast without explicitly calibrating any models to the data. To derive this relationship, we first sample a limited number of models from the prior distribution using geostatistical methods. For each model, we then apply two forward simulations: the first corresponds to the forward model of the data (past), the second corresponds to the forward model of the forecast (future). The relationship between observed data and forecast is generally highly non-linear, depending on the complexity of the prior distribution and the differences in the two forward operators. In order to derive a useful relationship, we first reduce the dimension of the data and the forecast through principal component analysis (PCA) related techniques in order to keep the most informative part of both sets. Then, we apply canonical correlation analysis (CCA) to establish a linear relationship between data and forecast in the reduced space components. If such a relationship exists, it is possible to directly sample the posterior distribution of the forecast with a multi-Gaussian framework. In this study, we apply this methodology to forecast the evolution with time of the distribution of temperature in a control panel in an alluvial aquifer. We simulate a heat tracing experiment monitored with both well logging probes and electrical resistivity tomography. We show (1) that the proposed method can be used to quantify the uncertainty on the forecast both spatially and temporally and (2) that spatially-distributed data acquired through geophysical methods help to significantly reduce the uncertainty of the posterior. [less ▲]

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See detailAssessing inter- and intramolecular continuous-flow strategies towards methylphenidate (Ritalin) hydrochloride
Gerardy, Romaric ULg; Winter, Marc; Vizza, Alessandra et al

in Reaction Chemistry and Engineering (2017)

The batch-to-flow translation of inter- and intramolecular strategies for the diastereoselective preparation of the active pharmaceutical ingredient threo-methylphenidate hydrochloride is presented. Both ... [more ▼]

The batch-to-flow translation of inter- and intramolecular strategies for the diastereoselective preparation of the active pharmaceutical ingredient threo-methylphenidate hydrochloride is presented. Both inter- and intramolecular strategies imply the telescoping of multiple processing steps and the generation of unstable diazo species under continuous-flow conditions. The intermolecular strategy relies on an unprecedented continuous-flow Rh-catalyzed intermolecular C–H carbene insertion, providing enriched threo-N-Boc methylphenidate in 38% or 19% isolated yield according to sequential or fully telescoped processes, respectively. Quantitative Boc-deprotection is carried out off-line. The intramolecular strategy relies on a continuous-flow thermal intramolecular C–H carbene insertion, providing enriched threo-methylphenidate hydrochloride in 70% isolated yield. A continuous-flow photochemical alternative is also presented. The critical step of the most promising intramolecular strategy is implemented on the mesoscale in a pilot-scale continuous-flow reactor. [less ▲]

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See detailAssessing Inter-and Intramolecular Continuous-Flow Strategies towards Methylphenidate Hydrochloride
Gerardy, Romaric ULg; Winter, Marc; Vizza, Alessandra et al

in Reaction Chemistry and Engineering (2017)

The batch-to-flow translation of inter- and intramolecular strategies for the diastereoselective preparation of the active pharmaceutical ingredient threo-methylphenidate hydrochloride is presented. Both ... [more ▼]

The batch-to-flow translation of inter- and intramolecular strategies for the diastereoselective preparation of the active pharmaceutical ingredient threo-methylphenidate hydrochloride is presented. Both inter- and intramolecular strategies imply the telescoping of multiple processing steps and the generation of unstable diazospecies under continuous-flow conditions. The intermolecular strategy relies on an unprecedented continuous-flow Rh-catalyzed intermolecular C-H carbene insertion, providing enriched threo-N-Boc methylphenidate in 38% or 19% isolated yield according to sequential or fully telescoped processes, respectively. Quantitative Boc-deprotection is carried out off-line. The intramolecular strategy relies on a continuous-flow thermal intramolecular C-H carbene insertion, providing enriched threo-methylphenidate hydrochloride in 70% isolated yield. A continuous-flow photochemical alternative is also presented. The critical step of the most promising intramolecular strategy is implemented on mesoscale in a pilot-scale continuous-flow reactor. [less ▲]

Detailed reference viewed: 17 (3 ULg)
See detailAssessing IT Innovations in US State Governments: a research framework
Markus, M. Lynne; Bui, Quang Neo; Jacobson, Dax D. et al

Poster (2011, August)

Detailed reference viewed: 45 (10 ULg)
Peer Reviewed
See detailAssessing kidney function
DELANAYE, Pierre ULg; Rule, AD

in Kimmel, PL; Rosenberg, ME (Eds.) Chronic Renal Disease (2014)

Detailed reference viewed: 7 (2 ULg)
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See detailAssessing local Ca2+ concentrations in calcium phosphate scaffolds by computational modelling
Manhas, Varun ULg; Guyot, Yann ULg; Chai, Yoke Chin et al

Poster (2013, October 24)

Detailed reference viewed: 31 (7 ULg)
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See detailAssessing overall heating efficiency of office buildings
Parys, Wout; Bertagnolio, Stéphane ULg; Saelens, Dirk et al

in Lemort, Vincent; Andre, Philippe; Bertagnolio, Stéphane (Eds.) 8th Conference on System Simulation in Buildings (2010, December 13)

The current methodology applied to estimate system efficiencies oversimplifies the complex interaction between the building, the occupants and the system. By detailed modelling of the building and the ... [more ▼]

The current methodology applied to estimate system efficiencies oversimplifies the complex interaction between the building, the occupants and the system. By detailed modelling of the building and the system, it is possible to define system efficiencies at the building level as a function of the system type and the building characteristics. In this study, the performance of a simple heating system in a middle-sized office building is simulated. The monthly average total efficiency, defined at the building level, proves to be very well correlated with the monthly ratio of heat gains over heat losses of the building. At ratios over 0.6, the efficiency falls sharply. This is mainly due to declining control efficiency. This secondary effect can annul partly the targeted increase in energy efficiency of well insulated and airtight buildings. [less ▲]

Detailed reference viewed: 49 (7 ULg)
See detailAssessing Pain and Communication in Disorders of Consciousness
Chatelle, Camille ULg; LAUREYS, Steven ULg

Book published by Psychology Press (2015)

Detailed reference viewed: 21 (1 ULg)
See detailAssessing pain in patients with disorders of consciousness
Chatelle, Camille ULg

Scientific conference (2013)

Detailed reference viewed: 10 (0 ULg)
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See detailAssessing Quality of Origin-Destination Matrices Derived from Activity and Travel Surveys: Results from a Monte Carlo Experiment
Cools, Mario ULg; Moons, Elke; Wets, Geert

in Proceedings of the 89th Annual Meeting of the Transportation Research Board (DVD-ROM) (2010)

To support policy makers combating travel-related externalities, quality data is required for the design and management of transportation systems and policies. To this end, large amounts of money have ... [more ▼]

To support policy makers combating travel-related externalities, quality data is required for the design and management of transportation systems and policies. To this end, large amounts of money have been spent on collecting household and person-based data. The main objective of this paper is to assess the quality of origin-destination matrices derived from household activity/travel surveys. To this purpose, a Monte Carlo experiment is set up to estimate the precision of OD-matrices given different sampling rates. The Belgian 2001 census data, containing work/school-related travel information for all 10,296,350 residents, are used for the experiment. For different sampling rates, 2000 random stratified samples are drawn. For each sample, three origin-destination-matrices are composed: one at municipality level, one at district level, and one at provincial level. The correspondence between the samples and the population is assessed by using the Mean Absolute Percentage Error (MAPE) and a censored version of the MAPE (MCAPE). The results show that no accurate OD-matrices can be directly derived from these surveys. Only when half of the population is queried, an acceptable OD-matrix is obtained at provincial level. Therefore, it is recommended to use additional information to better grasp the behavioral realism underlying destination choices and to collect information about particular origin-destination pairs by means of vehicle intercept surveys. In addition, the results suggest using the MCAPE next to traditional criteria to examine dissimilarities between different OD matrices. An important avenue for further research is the investigation of the effect of sampling proportions on travel demand model outcomes. [less ▲]

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See detailAssessing reactive power reserves with respect to operating constraints and voltage stability
Capitanescu, Florin ULg

in IEEE Transactions on Power Systems (2011), 26(4), 2224-2234

This paper proposes a two-step approach to evaluate reactive power reserves with respect to operating constraints and voltage stability for a set of postulated operating scenarios. The first step ... [more ▼]

This paper proposes a two-step approach to evaluate reactive power reserves with respect to operating constraints and voltage stability for a set of postulated operating scenarios. The first step determines the minimum overall needed reactive power reserves of generators such that the system withstands, from a static viewpoint, any postulated scenario. This problem is formulated as a security constrained optimal power flow (SCOPF) which includes operating constraints relative to all postulated scenarios. Particular attention is paid to the techniques aimed to reduce the large size of the SCOPF problem. The second step determines additional reserves to ensure voltage stability of scenarios for which, when modeling dynamic system behaviour, the reserves obtained by SCOPF are insufficient. These reserves are computed using a heuristic technique which relies on dynamic simulation. Numerical results on four test systems of 60, 118, 618, and 1203 buses support the interest of the approach. [less ▲]

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See detailAssessing resilience of dairy cattle by studying impact of heat stress on predicted feed intake
Vanrobays, Marie-Laure ULg; Hammami, Hedi ULg; Laine, Aurélie ULg et al

in Proceedings of the Third DairyCare Conference 2015 (2015)

Detailed reference viewed: 44 (18 ULg)