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See detailAssessing the Quality of Origin-Destination Matrices Derived from Activity Travel Surveys: Results from a Monte Carlo Experiment
Cools, Mario ULg; Moons, Elke; Wets, Geert

in Transportation Research Record: Journal of the Transportation Research Board (2010), 2183

To support policy makers combating travel-related externalities, quality data are required for the design and management of transportation systems and policies. To this end, much money has been spent on ... [more ▼]

To support policy makers combating travel-related externalities, quality data are required for the design and management of transportation systems and policies. To this end, much money has been spent on collecting household- and person-based data. The main objective of this paper is to assess the quality of origin-destination (O-D) matrices derived from household activity travel surveys. To this purpose, a Monte Carlo experiment is set up to estimate the precision of O-D matrices given different sampling rates. The Belgian 2001 census data, containing work- and school-related travel information for all 10,296,350 residents, are used for the experiment. For different sampling rates, 2,000 random stratified samples are drawn. For each sample, three O-D matrices are composed: one at the municipality level, one at the district level, and one at the 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 O-D matrices can be derived directly from these surveys. Only when half of the population is queried is an acceptable O-D matrix obtained at the provincial level. Therefore, use of additional information to grasp better the behavioral realism underlying destination choices and collection of information about particular O-D pairs by means of vehicle intercept surveys are recommended. In addition, results suggest using the MCAPE next to traditional criteria to examine dissimilarities between different O-D 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 the role of pore structure and porosity in composite electrodes through model thin film electrode studies
Krins, Natacha ULg; Shukla, Alpesh K.; Milliron, Delia J. et al

Poster (2012)

Detailed reference viewed: 8 (0 ULg)
See detailAssessing the role of porosity in composite electrodes through model thin film electrode studies
Krins, Natacha ULg; Shukla, Alpesh K.; Milliron, Delia J. et al

Poster (2012)

Detailed reference viewed: 9 (0 ULg)
See detailAssessing the role of porosity in composite electrodes through model thin film electrode studies
Krins, Natacha ULg; Shukla, Alpesh K.; Milliron, Delia J. et al

Poster (2012)

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See detailAssessing the Service Provided by a Connection-less Protocol
Leduc, Guy ULg

in Diaz, Michel (Ed.) Protocol Specification, Testing and Verification (1985, June)

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See detailAssessing the stimulant and sedative effects of alcohol with explicit and implicit measures in a balanced placebo design
Kreusch, Fanny ULg; Vilenne, Aurélie ULg; Quertemont, Etienne ULg

in Journal of Studies on Alcohol and Drugs (2013), 74(6), 923-930

Objective: Alcohol consumption is characterized by biphasic stimulant and sedative effects. In previous studies, various tools were used to assess these effects, including expectancy questionnaires ... [more ▼]

Objective: Alcohol consumption is characterized by biphasic stimulant and sedative effects. In previous studies, various tools were used to assess these effects, including expectancy questionnaires, implicit association tests, and self-report scales. The present study was aimed at clarifying the relationships between these measures. Method: Three different measures were used to directly or indirectly assess the stimulant and sedative effects of alcohol in 61 undergraduate students. The participants completed the Alcohol Expectancy Questionnaire (AEQ) and performed two unipolar Implicit Association Tasks to assess implicit associations between alcohol and the concepts of “stimulation” and “sedation.” The levels of alcohol consumption also were recorded by means of the Alcohol Use Disorders Identifi cation Test. An alcohol (0.4 g/kg) or placebo challenge was then administered using a balanced placebo design. After alcohol/placebo administration, the participants completed the Biphasic Alcohol Effects Scale (BAES). Results: Alcohol consumption signifi cantly correlated with AEQ alcohol explicit expectancies of arousal and relaxation, whereas no signifi cant correlations were obtained with the implicit associations. There were positive correlations between AEQ and BAES subscales, especially for the arousal subscale of the AEQ. Self-reported sedation recorded with the BAES was signifi cantly affected by what the participants believed that they had drunk but not by the actual consumption of alcohol. Conclusions: These fi ndings indicate that alcohol explicit expectancies of arousal measured with the AEQ best predict current alcohol consumption. Regarding explicit measures of alcohol-induced stimulation and sedation, BAES subscales seem to be more affected by alcohol drinking expectations than by actual alcohol consumption. [less ▲]

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See detailAssessing the success of river restoration projects through Geomorphology
Peeters, Alexandre ULg; Verniers, Gisèle; De le Court, Bernard et al

Conference (2013, August 30)

In the context of the Water Framework Directive’s goal of attaining “good ecological status”, a LIFE+ project (called Walphy), co-funded by the European Union and the Service Public de Wallonie, was ... [more ▼]

In the context of the Water Framework Directive’s goal of attaining “good ecological status”, a LIFE+ project (called Walphy), co-funded by the European Union and the Service Public de Wallonie, was launched in 2009. It aims to undertake experimental river restoration projects and to assess their success on the basis of ecological and geomorphological monitoring. Geomorphological monitoring differs depending on the type of restoration project: improvement of longitudinal continuity or transversal continuity. Restoration projects involving longitudinal continuity concern courses where obstacles impede the free movement of fish and sediment. In the Bocq basin, many of these obstacles (old weirs between 1 and 3 m high) have been removed. The release of sediment was studied using traced pebbles (PIT tags), which enable the recovery of bedload transport to be highlighted. Additional monitoring is based on the comparison of topographic surveys and cross-sections carried out pre- and post-removal. This can show a recovery of the natural transport of sediment when stream bed aggradation is observed downstream from the removed dam. Restoration projects involving transversal continuity concern straightened courses with artificial banks and therefore poor stream-floodplain connectivity. These works consist of enhancing river channels and restoring meanders or banks. Geomorphological monitoring is also based on surveys conducted pre- and post-restoration work. Some reaches have been improved by the reintroduction of spawning gravel. Several methods were used to characterize the clogging of this gravel reintroduction (hydraulic conductivity, wooden stakes). In addition, the mobility of this gravel was monitored using traced pebbles (PIT tags). Finally, restoration works and their stability and resistance to erosion are considered in relation to flood characteristics (discharge, recurrence, specific stream power and shear stress). [less ▲]

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See detailAssessing the Thermal Performance of Bedouin Tents in Hot Climates
Attia, Shady ULg

in ASHRAE Energy & Indoor Environment for Hot Climates (2014, February 24)

The aims of this study it to improve conditions inside Bedouin tents shelters and to develop tools to assess shelter quality and comfort. A prototype tent was tested in hot conditions with an internal ... [more ▼]

The aims of this study it to improve conditions inside Bedouin tents shelters and to develop tools to assess shelter quality and comfort. A prototype tent was tested in hot conditions with an internal vapor load. Temperature, humidity measurements and air speed were taken inside the shelter while the external temperature was maintained at 40°C (104°F). Building performance simulation was conducted to produce a simulation model. A model of a tent was constructed using the EnergyPlus simulation software and were calibrated with the test data. The shelter models were simulated in Wadi Rum, Jordan using real data from. The feasibility of heating the tent using only the casual gains from occupants and solar radiation was investigated, although it was found that a tent heated in this way would only be appropriate in spring and autumn. Design issues included coping with stratification of air temperature inside the tent, improving thermal comfort without compromising fabricating the materials cheaply and simply. The validity of the results is limited by the lack of measured data for rates of air infiltration. [less ▲]

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See detailAssessing the vulnerability of sites in the East African Rift Valley to natural hazards: case study of Bujumbura, Burundi
Nibigira, Léonidas ULg; Havenith, Hans-Balder ULg; Dewals, Benjamin ULg et al

Conference (2013, November 13)

Due to the geomorphologic, structural and climatic context, the East African Rift Valley is prone to many natural hazards. The locally high density of the population contributes to related risk. As a ... [more ▼]

Due to the geomorphologic, structural and climatic context, the East African Rift Valley is prone to many natural hazards. The locally high density of the population contributes to related risk. As a result, the impacts on the habitat and infrastructures are constantly increasing. This work is based on a case study near the city of Bujumbura, which, for decades, has been affected by severe floods. Based on a study focusing on one of its rivers, the river Ntahangwa, this work tries to answer some questions related to the potential causes and ways of prevention and management of flood risk. The analysis is based on hydrological considerations while having a look at the possible mutual influences between these hydrological risks and geodynamic hazards. The methodology uses rainfall, geographic, demographic, topographic, and elevation data. Hydraulic modeling reveals the extent of the flood hazard according to its likelihood of occurrence and its sensitivity to geodynamic disturbances. This led us to propose solutions and related prevention/remediation measures. Considering the vulnerability of the population, it is clear that a change of people’s behavior is needed to reduce the total risk they’re exposed to, both with respect to the choice of construction areas and to all kinds of activities related to rivers exploitation. [less ▲]

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See detailAssessing the World Ocean ventilation timescales with simple analogs - the leaky funnel model
Mouchet, Anne ULg; Deleersnijder, Eric

Poster (2011, May)

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See detailAssessing the World Ocean ventilation timescales with simple analogs - the leaky funnel model
Mouchet, Anne ULg; Deleersnijder, Eric

Conference (2009, February)

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See detailAssessing tropical forage species used as pig feed ingredients in the western provinces of the Democratic Republic of the Congo
Kambashi Mutiaka, Bienvenu ULg

Doctoral thesis (2014)

The use of forage species to feed pig goes back to immemorial times. If forage is no longer used in industrial farms with genetically-improved breeds, its accounts for an important part of pig diets in ... [more ▼]

The use of forage species to feed pig goes back to immemorial times. If forage is no longer used in industrial farms with genetically-improved breeds, its accounts for an important part of pig diets in smallholder pig production systems in tropical areas including the Western provinces of the Democratic Republic of the Congo (DRC). The aim of this research thesis was to assess the relevancy of the use of local forage resources as a strategy to reduce reliance of pig production systems on concentrate feed ingredients in tropical environment, by identifying plant species available to smallholders with interesting nutritional value that could partly replace concentrates in the diets. First, smallholder pig production systems in two western provinces of the DRC were characterized and the most used forage species in pigs identified. Their nutritional value was determined using an in vitro model of the pig’s gastro-intestinal tract. It was concluded that Manihot esculenta, Ipomoea batatas, Moringa oleifera, and legume species exhibit an interesting profile for feeding pigs while grasses, Eichhornia crassipes, Acacia mangium and Cajanus cajan should be discouraged. Feeding values of Psophocarpus scandens, Vigna unguiculata, Stylosanthes guianensis, and Pueraria. phaseoloides were measured by assessing the voluntary feed intake of forage hays-based diets and their digestibility. Finally, the economic impact of feeding Psophocarpus scandens, Vigna unguiculata, and Stylosanthes guianensis, was measured through growth performance, carcass quality, and production costs determination. It is concluded that although forage species reduce the nutritive value and the growth of animals, the investigated legumes do not impact negatively the economical balance of concentrate-fed pigs when forage accounts for approx. 10 % of the diet. The ability of some forage species to improve performances of animals fed ill-balanced diets as usually practiced by smallholder farmers in the DRC should be investigated as it is suspected that under less favourable conditions, conclusions on the usefulness of forage legumes in pigs might be more positive [less ▲]

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See detailAssessing urbanisation effects on rainfall-runoff using a remote sensing supported modelling strategy
Verbeiren, Boud; Van de Voorde, Tim; Canters, Frank et al

in International Journal of Applied Earth Observation and Geoinformation (2013), 21

This paper aims at developing a methodology for assessing urban dynamics in urban catchments and the related impact on hydrology. Using a multi-temporal remote sensing supported hydrological modelling ... [more ▼]

This paper aims at developing a methodology for assessing urban dynamics in urban catchments and the related impact on hydrology. Using a multi-temporal remote sensing supported hydrological modelling approach an improved simulation of runoff for urban areas is targeted. A time-series of five medium resolution urban masks and corresponding sub-pixel sealed surface proportions maps was generated from Landsat and SPOT imagery. The consistency of the urban mask and sealed surface proportion timeseries was imposed through an urban change trajectory analysis. The physically based rainfall-runoff model WetSpa was successfully adapted for integration of remote sensing derived information of detailed urban land use and sealed surface characteristics. A first scenario compares the original land-use class based approach for hydrological parameterisation with a remote sensing sub-pixel based approach. A second scenario assesses the impact of urban growth on hydrology. Study area is the Tolka River basin in Dublin, Ireland. The grid-based approach of WetSpa enables an optimal use of the spatially distributed properties of remote sensing derived input. Though change trajectory analysis remains little used in urban studies it is shown to be of utmost importance in case of time series analysis. The analysis enabled to assign a rational trajectory to 99% of all pixels. The study showed that consistent remote sensing derived land-use maps are preferred over alternative sources (such as CORINE) to avoid over-estimation errors, interpretation inconsistencies and assure enough spatial detail for urban studies. Scenario 1 reveals that both the class and remote sensing sub-pixel based approaches are able to simulate discharges at the catchment outlet in an equally satisfactory way, but the sub-pixel approach yields considerably higher peak discharges. The result confirms the importance of detailed information on the sealed surface proportion for hydrological simulations in urbanised catchments. In addition a major advantage with respect to hydrological parameterisation using remote sensing is the fact that it is site- and period-specific. Regarding the assessment of the impact of urbanisation (scenario 2) the hydrological simulations revealed that the steady urban growth in the Tolka basin between 1988 and 2006 had a considerable impact on peak discharges. Additionally, the hydrological response is quicker as a result of urbanisation. Spatially distributed surface runoff maps identify the zones with high runoff production. It is evident that this type of information is important for urban water management and decision makers. The results of the remote sensing supported modelling approach do not only indicate increased volumes due to urbanisation, but also identifies the locations where the most relevant impacts took place. [less ▲]

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See detailAssessing variability of literature based methane indicator traits in a large dairy cow population
Kandel, Purna Bhadra ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2015), 19(1), 11-19

Description du sujet. La production laitière est reconnue comme une des sources majeures d’émissions de méthane (CH4). Le recours à un programme de sélection spécifique pourrait être une bonne méthode ... [more ▼]

Description du sujet. La production laitière est reconnue comme une des sources majeures d’émissions de méthane (CH4). Le recours à un programme de sélection spécifique pourrait être une bonne méthode pour optimiser les émissions de méthane par les vaches laitières. Le développement d’un tel programme nécessiterait un nombre important d’enregistrements relatifs aux émissions de méthane. Malheureusement, aucune méthode pratique et bon marché n’existe actuellement pour créer une telle base de données. Cependant, quatre indicateurs CH4 basés sur les quantités en acides gras dans la matière grasse laitière ont été recensés dans la littérature. Objectifs. L’objectif de cette étude est d’utiliser ces indicateurs de la littérature afin d’apprécier la variabilité des émissions de méthane éructées par les vaches laitières. Méthode. Ces indicateurs utilisent les quantités en acides gras obtenues par chromatographie en phase gazeuse. Comme ce type de données n’est pas disponible pour toute la population laitière, un échantillon de 602 analyses chromatographiques a été créé dans cette étude afin de développer une équation de calibrage permettant de prédire les quantités de méthane émises à partir du spectre moyen infrarouge (MIR) du lait qui est disponible pour toutes les vaches étudiées. Ensuite, l’équation de calibrage ainsi obtenue a été appliquée sur 604 028 données spectrales enregistrées entre 2007 et 2011 auprès de 70 872 vaches au cours de leurs trois premières lactations afin de prédire les quantités de méthane émises. Les paramètres génétiques de ces nouveaux indicateurs méthane prédits par MIR ont également été estimés en utilisant un modèle animal de type jour de test avec régressions aléatoires. Résultats. Ces quantités prédites par MIR variaient selon une gamme attendue s’étalant entre 350 ± 40 et 449 ± 65 g par jour. L’émission prédite moyenne de CH4 en g par jour augmentait au début de la lactation, atteignait sa plus haute concentration au pic de lactation et ensuite diminuait jusqu’à la fin de la lactation. Les héritabilités journalières moyennes variaient entre 0,29-0,35 ; 0,26-0,40 et 0,22-0,37 pour les différents indicateurs méthane étudiés au cours des trois premières lactations. Les plus grandes différences entre les valeurs d’élevage estimées pour des taureaux ayant des filles en production émettant le plus et le moins de méthane étaient de 24,18 ; 29,33 et 27,77 kg par lactation pour les trois premières lactations. Des corrélations faiblement négatives ont été observées entre les indicateurs CH4 et la quantité de lait. À l’inverse, des corrélations positives ont été estimées entre ces mêmes indicateurs et les taux en matières grasses et en protéines. Conclusions. Cette étude montre la possibilité de prédire des indicateurs méthane issus de la littérature et utilisant les concentrations en acides gras dans la matière grasse laitière à partir de la spectrométrie MIR. De plus, cette étude suggère également à partir des paramètres génétiques obtenus l’existence d’une variabilité phénotypique et génétique des quantités de méthane éructées par les vaches laitières Holstein. [less ▲]

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See detailAssessing wind comfort in urban planning
Reiter, Sigrid ULg

in Environment & Planning B : Planning & Design (2010), 37(5), 857-873

There are increasing concerns regarding the quality of urban public spaces. Wind is one important environmental factor that influences pedestrians’ comfort and safety. In modern cities, there are more and ... [more ▼]

There are increasing concerns regarding the quality of urban public spaces. Wind is one important environmental factor that influences pedestrians’ comfort and safety. In modern cities, there are more and more high constructions and complex forms which can involve significant problems of wind discomfort around these buildings. Today, architects and town planners need guidelines and simple design tools to take account of wind in their projects. This paper addresses the progress made towards computational fluid dynamics (CFD) simulations for assessing wind comfort in urban planning. We validated Fluent software for wind studies in urban environments by comparing our simulations results with wind tunnel tests. This validation shows that wind mean velocities around buildings can be simulated numerically with a very high degree of accuracy. Based on the results of a great number of CFD simulations, we developed a methodology and simple graphical tools to quantify critical wind speeds around buildings. This article should thus help in practice architects and town planners to design our built environment. Moreover, this paper shows how numerical modeling is now a high-performance tool to work out useful guidelines and simple design tools for urban planners. [less ▲]

Detailed reference viewed: 269 (24 ULg)
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See detailAssessment and detection of pain in noncommunicative severely brain-injured patients.
Schnakers, Caroline ULg; Chatelle, Camille ULg; Majerus, Steve ULg et al

in Expert Review of Neurotherapeutics (2010), 10(11), 1725-31

Detecting pain in severely brain-injured patients recovering from coma represents a real challenge. Patients with disorders of consciousness are unable to consistently or reliably communicate their ... [more ▼]

Detecting pain in severely brain-injured patients recovering from coma represents a real challenge. Patients with disorders of consciousness are unable to consistently or reliably communicate their feelings and potential perception of pain. However, recent studies suggest that patients in a minimally conscious state can experience pain to some extent. Pain monitoring in these patients is hence of medical and ethical importance. In this article, we will focus on the possible use of behavioral scales for the assessment and detection of pain in noncommunicative patients. [less ▲]

Detailed reference viewed: 40 (3 ULg)