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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: 37 (16 ULg)
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See detailAssessing Response to Industrial Marketing Strategy
Choffray, Jean-Marie ULg; Lilien, Gary L.

in Journal of Marketing (1978)

An operational structure for use in making new industrial products design and marketing decisions

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See detailAssessing spatio-temporal variability and trends in modelled and measured Greenland Ice Sheet albedo (2000–2013)
Alexander, P.; Tedesco, M.; Fettweis, Xavier ULg et al

in Cryosphere (The) (2014), 8

Accurate measurements and simulations of Greenland Ice Sheet (GrIS) surface albedo are essential, given the role of surface albedo in modulating the amount of absorbed solar radiation and meltwater ... [more ▼]

Accurate measurements and simulations of Greenland Ice Sheet (GrIS) surface albedo are essential, given the role of surface albedo in modulating the amount of absorbed solar radiation and meltwater production. In this study, we assess the spatio-temporal variability of GrIS albedo during June, July, and August (JJA) for the period 2000–2013. We use two remote sensing products derived from data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS), as well as outputs from the Modèle Atmosphérique Régionale (MAR) regional climate model (RCM) and data from in situ automatic weather stations. Our results point to an overall consistency in spatio-temporal variability between remote sensing and RCM albedo, but reveal a difference in mean albedo of up to ~0.08 between the two remote sensing products north of 70° N. At low elevations, albedo values simulated by the RCM are positively biased with respect to remote sensing products by up to ~0.1 and exhibit low variability compared with observations. We infer that these differences are the result of a positive bias in simulated bare ice albedo. MODIS albedo, RCM outputs, and in situ observations consistently indicate a decrease in albedo of −0.03 to −0.06 per decade over the period 2003–2013 for the GrIS ablation area. Nevertheless, satellite products show a decline in JJA albedo of −0.03 to −0.04 per decade for regions within the accumulation area that is not confirmed by either the model or in situ observations. These findings appear to contradict a previous study that found an agreement between in situ and MODIS trends for individual months. The results indicate a need for further evaluation of high elevation albedo trends, a reconciliation of MODIS mean albedo at high latitudes, and the importance of accurately simulating bare ice albedo in RCMs. [less ▲]

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See detailAssessing steady-state, multivariate experimental data using Gaussian Processes: the GPExp open-source library
Quoilin, Sylvain ULg; Schrouff, Jessica ULg

in Energies (2016), 9(6),

Experimental data are subject to different sources of disturbance and errors, whose importance should be assessed. The level of noise, the presence of outliers or a measure of the “explainability” of the ... [more ▼]

Experimental data are subject to different sources of disturbance and errors, whose importance should be assessed. The level of noise, the presence of outliers or a measure of the “explainability” of the key variables with respect to the externally-imposed operating condition are important indicators, but are not straightforward to obtain, especially if the data are sparse and multivariate. This paper proposes a methodology and a suite of tools implementing Gaussian processes for quality assessment of steady-state experimental data. The aim of the proposed tool is to: (1) provide a smooth (de-noised) multivariate operating map of the measured variable with respect to the inputs; (2) determine which inputs are relevant to predict a selected output; (3) provide a sensitivity analysis of the measured variables with respect to the inputs; (4) provide a measure of the accuracy (confidence intervals) for the prediction of the data; (5) detect the observations that are likely to be outliers. We show that Gaussian processes regression provides insightful numerical indicators for these purposes and that the obtained performance is higher or comparable to alternative modeling techniques. Finally, the datasets and tools developed in this work are provided within the GPExp open-source package. [less ▲]

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See detailAssessing structure potential in soil and water conservation: monitoring top soil hydrology from micro to field scale.
Kummert, Nora ULg; Beckers, Eléonore ULg; Roisin, Christian et al

in Wollesen de Jonge, Lis; Moldrup, Per; Lindblad Vendelboe, Anders (Eds.) 1st international conference and exploratory workshop on soil architecture and physico-chemical functions "CESAR" (2010)

Soil structure is a key parameter influencing erosion and water transfers. This paper describes an experiment that covers different aspects of soil structure. Three tillage systems are tested: reduced ... [more ▼]

Soil structure is a key parameter influencing erosion and water transfers. This paper describes an experiment that covers different aspects of soil structure. Three tillage systems are tested: reduced tillage, and two ploughing systems. At micro-scale, analyses are tomography which study images to determine porosity characteristics (connectivity, size, number…) and pF curves where total available water and effective porosity are deducted. At field scale, soil losses and runoff are collected and measured after rainfall simulation on plots for the different tillage systems. The comparison of the results for both scales shows the links between phenomenons at those scales. [less ▲]

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See detailAssessing suicide ideations in Traumatic Brain Injury (TBI) patients by using depression scales
Desseilles, Martin ULg; Gosselin, Nadia; Perroud, Nader

in Journal of Head and Trauma Rehabilitation (2013), 28(2), 149-150

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See detailAssessing the ability of rural agrarian areas to provide culturalecosystem services (CES): A multi scale social indicator framework(MSIF)
Carvalho-Ribeiro, Sónia; Pinto Correia, Teresa; Paracchini, Maria Luisa et al

in Land Use Policy (2016), 53

Assessing the ways in which rural agrarian areas provide Cultural Ecosystem Services (CES) is provingdifficult to achieve. This research has developed an innovative methodological approach named as ... [more ▼]

Assessing the ways in which rural agrarian areas provide Cultural Ecosystem Services (CES) is provingdifficult to achieve. This research has developed an innovative methodological approach named as MultiScale Indicator Framework (MSIF) for capturing the CES embedded into the rural agrarian areas. Thisframework reconciles a literature review with a transdisciplinary participatory workshop. Both of thesesources reveal that societal preferences diverge upon judgemental criteria which in turn relate to differentvisual concepts that can be drawn from analyzing attributes, elements, features and characteristics of ruralareas. We contend that it is now possible to list a group of possible multi scale indicators for stewardship,diversity and aesthetics. These results might also be of use for improving any existing European indicatorsframeworks by also including CES. This research carries major implications for policy at different levels ofgovernance, as it makes possible to target and monitor policy instruments to the physical rural settingsso that cultural dimensions are adequately considered. There is still work to be developed on regionalspecific values and thresholds for each criteria and its indicator set. In practical terms, by developing theconceptual design within a common framework as described in this paper, a considerable step forwardtoward the inclusion of the cultural dimension in European wide assessments can be made. [less ▲]

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See detailAssessing the Accuracy of Simulation Model for Septoria Leaf Blotch Disease Progress on Winter Wheat.
El Jarroudi, Moussa ULg; Delfosse, Philippe; Maraite, Henri et al

in Plant Disease (2009), 93

A mechanistic model, PROCULTURE, for assessing the development of each of the last five leaf layers and the progress of Septoria leaf blotch, caused by Septoria tritici (teleomorph Mycosphaerella ... [more ▼]

A mechanistic model, PROCULTURE, for assessing the development of each of the last five leaf layers and the progress of Septoria leaf blotch, caused by Septoria tritici (teleomorph Mycosphaerella graminicola), has been applied on susceptible and weakly susceptible winter wheat (Triticum aestivum) cultivars in two locations (Everlange and Reuland) in Luxembourg over a 3-year period (2000 to 2002). A double performance assessment of PROCULTURE was conducted in this study. First, the capability of PROCULTURE to correctly simulate S. tritici incidence was checked. Second, the model's ability to accurately estimate disease severity was assessed on the basis of the difference between simulated and observed levels of disease development at each leaf layer. The model accurately predicted disease occurrence in the 2000 and 2002 seasons, on susceptible and semi-susceptible cultivars, with a probability of detection (POD) exceeding 0.90. However, in 2001, even though the POD never fell below 0.90, the false alarm ratio (FAR) was too high to consider the simulations satisfactory. Concerning the evaluation of disease severity modeling, statistical tests revealed accurate simulations performed by PROCULTURE for susceptible cultivars in 2000 and 2002. By contrast, for weakly susceptible cultivars, the model overestimated disease severity, especially for the upper leaves, for the same period. [less ▲]

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See detailAssessing the accuracy of the surface gravity determination in late-type stars with solar-like pulsators
Morel, Thierry ULg; Miglio, Andrea ULg

in Monthly Notices of the Royal Astronomical Society (2012), 419

The frequency of maximum oscillation power measured in dwarfs and giants exhibiting solar-like pulsations provides a precise, and potentially accurate, inference of the stellar surface gravity. An ... [more ▼]

The frequency of maximum oscillation power measured in dwarfs and giants exhibiting solar-like pulsations provides a precise, and potentially accurate, inference of the stellar surface gravity. An extensive comparison for about 40 well-studied pulsating stars with gravities derived using classical methods (ionization balance, pressure-sensitive spectral features or location with respect to evolutionary tracks) supports the validity of this technique and reveals an overall remarkable agreement with mean differences not exceeding 0.05 dex (although with a dispersion of up to ˜0.2 dex). It is argued that interpolation in theoretical isochrones may be the most precise way of estimating the gravity by traditional means in nearby dwarfs. Attention is drawn to the usefulness of seismic targets as benchmarks in the context of large-scale surveys. [less ▲]

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See detailAssessing the adequacy of past antidepressant trials: a clinician's guide to the antidepressant treatment response questionnaire.
Desseilles, Martin ULg; Witte, Janet; Chang, Trina E. et al

in The Journal of clinical psychiatry (2011), 72(8), 1152-4

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See detailAssessing the anti-androgenic activities of chemicals and surface waters using Brachionus calyciflorus and the anti-YAS test
Joaquim-Justo, Célia ULg; Bellisai, Giulia; Chalon, Carole et al

Conference (2015, September)

It has been shown over the past decade that Brachionids are sensitive to some vertebrate hormones and environmental contaminants with endocrine disrupting properties in vertebrates. Several Brachionus ... [more ▼]

It has been shown over the past decade that Brachionids are sensitive to some vertebrate hormones and environmental contaminants with endocrine disrupting properties in vertebrates. Several Brachionus species have been shown to be particularly sensitive to progestagens and anti-androgens. Institutions in charge of the monitoring and the management of the environment, need to constantly update their tools to ensure optimal detection of hazardous chemicals and to achieve adequate protection of the environment. With that intent, we compared the results obtained when testing the androgenic and anti-androgenic activity of substances and surface water samples/effluents with the YAS and anti-YAS tests and by sexual reproduction tests with Brachionus calyciflorus. Respective sensitivities and feasibilities of both these types of tests have been assessed and will be discussed. [less ▲]

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See detailAssessing the causes inducing lengthening of hospital stays by means of the Appropriateness Evaluation Protocol.
Fontaine, Pierre ULg; Jacques, Jessica ULg; Gillain, Daniel ULg et al

in Health Policy (2011)

OBJECTIVES: The objective is to evaluate the use of the Appropriateness Evaluation Protocol (AEP) as a screening tool for determining the causes of the non-justified days to help hospitals to decrease the ... [more ▼]

OBJECTIVES: The objective is to evaluate the use of the Appropriateness Evaluation Protocol (AEP) as a screening tool for determining the causes of the non-justified days to help hospitals to decrease the length of stay while preserving the quality of care. METHODS: Three successive cross-sectional surveys were conducted from 2003 till 2005, in 23 Belgian hospitals. During this period, 10921 days were audited by means of the AEP. This study is focused on adult acute non-intensive care units. The appropriateness of each day of the sample was assessed, and for those considered as inappropriate, the reasons explaining the prolongation of the stay were investigated. RESULTS: The proportion of inappropriate days was 24.61%. There is a high variability across specialties and hospitals. Regarding inappropriate days, the analysis of causes of prolongation, globally, by bed index or by hospital, indicated clearly internal and external factors that lengthen stays. The most frequent reasons are waits for an examination (22%) and the lack of extra-hospital structures (31%). CONCLUSIONS: The use of AEP as a tool of internal audit to measure the proportion of non-justified days and their causes turns out to be possible and the obtained results has provided some accurate and useful information for the participating, and allowed them to take concrete decisions which lead to shrinking of the length of hospital stay. [less ▲]

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See detailAssessing the effect of a catchment-scale restoration project in Wallonia (Belgium)
Peeters, Alexandre ULg; Verniers, Gisèle; De le Court, Bernard

in Angelopoulos, Natalie; Buijse, Tom; van Oorschot, Mijke (Eds.) et al Proceedings of the International Conference on River and Stream Restoration “Novel Approaches to Assess and Rehabilitate Modified Rivers”. FP7 REFORM deliverable 7.5. (2015)

In the context of fulfilling the Water Framework Directive requirements, the LIFE+ project Walphy allowed experimental restoration projects to be undertaken on two medium-size catchments of the Meuse ... [more ▼]

In the context of fulfilling the Water Framework Directive requirements, the LIFE+ project Walphy allowed experimental restoration projects to be undertaken on two medium-size catchments of the Meuse basin in Wallonia (Belgium) between 2009 and 2014. Before undertaking sustainable rehabilitation measures, a multi-scale assessment of hydromorphological conditions (catchment, stream and site) was conducted. It was based on a variety of variables characterizing the river system and its geomorphic processes (e.g. sediment transport), along with human-induced disturbances (e.g. barriers to river continuity). The Bocq catchment has been subject to a large-scale restoration project through the removal or modification of 20 barriers (mainly old weirs), reconnecting the Bocq with the Meuse. In addition, 2.6 km of straightened courses were improved by restoring meanders or diversifying habitats through a wide range of rehabilitation techniques. The success of the restoration projects was evaluated on the basis of a multi-disciplinary monitoring. We compared hydromorphological parameters and biological diversity of benthic invertebrates, fish and macrophytes. 2-3 years post-rehabilitation, hydromorphology was significantly improved. Depending on the rehabilitation measures, the restoration effects observed for invertebrates and fish differ. Weir removal and restored meanders have resulted in the most positive effects, while habitat diversification has led to more contrasted results, depending on the level of ambition. The geomorphological monitoring has focused on the effectiveness of spawning gravel rehabilitation and the effect of barriers on sediment transport. Topographic surveys and the use of pebble tracers have highlighted a natural bedload transport following a weir removal. [less ▲]

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