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See detailA Methodology for Updating Large Scale Ortho-Photomaps by Means of VHR Satellite imagery
Donnay, Jean-Paul ULg; Seba, Gautier; de Béthune, Stanislas et al

in Maktav, Derya; Jürgens, Carsten; Erber Sunar, Filiz (Eds.) et al Proceedings of the 3d International Symposium of Remote Sensing of Urban Areas (2002)

Some authorities (DGPL) of the Walloon Region (Belgium) are involved in the realization of a complete regional coverage (16,844 km²) of natural colour ortho-photomap to be used at large scales (up to 1 ... [more ▼]

Some authorities (DGPL) of the Walloon Region (Belgium) are involved in the realization of a complete regional coverage (16,844 km²) of natural colour ortho-photomap to be used at large scales (up to 1:4000). These are made of very high-resolution digital ortho-rectified aerial photos presented as raster files. Those rasters are grouped by corresponding administrative boundaries and distributed to the local authorities in order to be used for various land and urban planning purposes. One goal of the DGPL is to provide the local administrations with up to date image data, within the limits of some obvious financial constraints. Because significant changes in the landscape appear at different rates over the time and space, it was suggested to devise a methodology to find out these changes would require a rapid update of the imagery. In regard to this situation, a pilot project has been set up in the year 2000 aiming at detecting the location, the extent and the nature of landscape changes in contrasted areas - urban, suburban, rural - from adequately processed very high resolution (VHR) satellite images - typically Ikonos multi-spectral (4m) and panchromatic (1m) images. Hence, this project had to cope with various issues related to multi-source analysis, geometric and radiometric aspects of the processing VHR data, diachronic analysis, in order to provide the administration with the basic knowledge and the appropriate tools to carry out the proposed task. This communication presents the proposed operational methodology for change detection including all processing steps from the digital image processing (image fusion technique, ortho-rectification analysis, change detection schemes). Along the way it also introduces an assessment of the possible complementarities and convergence of VHR satellite imagery and aerial photography. [less ▲]

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See detailMETHODOLOGY OF ANNOTATING VIDEOS AND STILL IMAGES AND DEVELOPMENT OF THE SOFTWARE COVER
Guillaumont, Brigitte; Carré, Cyril ULg; van den Beld, Inge et al

Conference (2011, June)

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See detailMethodology of high speed railway network planning
Marchal, Jean ULg; Han, Baoming

in Proceedings of the Second Conference of Hongkong Society for Transportation Studies HKSTS (1997)

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See detailMethodology of the biological risk classification of animal pathogens in Belgium
Van Vaerenbergh, B.; Koenen, Frank; Pauwels, K. et al

in Revue Scientifique et Technique / Office International des Epizooties = Revista Cientifica y Tecnica / Officina Internacional de Epizootias = Scientific and Technical Review / International Office of Epizootics (2010), 29(3), 513-522

The biological hazards posed by micro-organisms have lead to their categorisation into risk groups and the elaboration of classification lists. Current classification systems rely on criteria defined by ... [more ▼]

The biological hazards posed by micro-organisms have lead to their categorisation into risk groups and the elaboration of classification lists. Current classification systems rely on criteria defined by the World Health Organization, considering the severity of the disease the micro-organism might cause, its ability to spread and the availability of prophylaxis or efficient treatment. Animal pathogens are classified according to the definitions of the World Organization of Animal Health whereby also economic aspects are considered. In Europe, classification is often directly linked to containment measures. The Belgian classification however, considers only the inherent characteristics of the micro-organism, not its use, making it independent of containment measures. Also a common list for human and animal pathogens is elaborated, allowing a comprehensive approach. Evolution of scientific knowledge requires regular updating of classification lists. This paper describes the particularities of the Belgian classification and the methodology that was used for its peer-reviewed revision, hereby focusing on animal pathogens. [less ▲]

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See detailA methodology to assess the exactness of Stream Network modeling process on agricultural watersheds
Ouedraogo, Mohamar ULg; Degre, Aurore ULg; Beckers, Eléonore ULg et al

in Geophysical Research Abstracts (2011)

The goal of our study is to evaluate the exactness of stream network modeling process on agricultural watersheds. Agricultural watersheds topography is always changing, making it difficult to be modeled ... [more ▼]

The goal of our study is to evaluate the exactness of stream network modeling process on agricultural watersheds. Agricultural watersheds topography is always changing, making it difficult to be modeled. According to the standard ISO-7078 (ISO-7078, 1985) of the Inernational Organization of Standardization, the exactness of a measurement process or a modeled process can be defined as the difference between results obtained from the measurement process and a reference accepted as the «true value». A small watershed of a dozen hectares size has been surveyed by terrestrial LiDAR (Light Detecting And Ranging) scanner and photogrammetrical techniques to produce a row data of 30 cm resolution. Three interpolation techniques i.e. natural neighbourg, multiquadratic radial basis function and inverse distance weighted have been applied on the original data to create original digital elevation models (DEM) of 1 m resolution. RTK (Real Time Kinematics) GPS (Global Positionning System) ground control points have been surveyed on the watershed to evaluate DEM errors and fit a variogram that is used by a conditional sequencial gaussian simulation model to generate error maps. However, ground control point’s elevations accuracy is depending on the microtopography of parcels in an agricultural watershed. Depending on the crop that is planned by the farmer, the soil tillage will be different, and soil structure and roughness can considerably influence ground control point’s elevation. Analysis of variance and geostatistical methods have been applied on total station and RTK GPS data to estimate intervals in which, ground control points elevations vary. These intervals have been estimated for two parcels that soils are tilled in different ways. These errors are added to the generated errors maps to create final error maps. The final errors maps are added to the original DEM to create likely DEM realizations for the watershed (Temme and al., 2007). Then, two spurious sinks filtering methods (Colson 2006; Lindsay and Creed, 2005) and one flat area treatment method (Jenson and Domingue, 1988) are applied on each DEM realization for preprocessing. Finally, the three common flow direction extraction methods (D8, D-infity and Multiple Flow Direction) are applied on each preprocessed DEM to extract stream Network. The extracted stream network is overlapped with RTK GPS field positioned stream network i.e. a polyline format data. To estimate the exactness of the stream extraction methods, the polyline format is converted in raster format. That allows to compute for each pixel of the observed stream network, the distance to the extracted stream network. Then, for each pixel the mean distance can be calculated, and can be represented through the stream network. LiDAR technology is becoming useful for environment modeling because of his accuracy. Such quantity of data is not free of errors. This research will allow us to estimate the uncertainty of stream network modeled from agricultural watersheds by considering the main sources of errors that are propagated through computing processes. [less ▲]

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See detailA Methodology to Improve the Robustness of Gas Turbine Engine Performance Monitoring Against Sensor Faults
Dewallef, Pierre ULg; Borguet, Sébastien ULg

in Journal of Engineering for Gas Turbines and Power (2013), 135(5),

For turbine engine performance monitoring purposes, system identification techniques are often used to adapt a turbine engine simulation model to some measurements performed while the engine is in service ... [more ▼]

For turbine engine performance monitoring purposes, system identification techniques are often used to adapt a turbine engine simulation model to some measurements performed while the engine is in service. Doing so, the simulation model is adapted through a set of so-called health parameters whose values are intended to represent a faithful image of the actual health condition of the engine. For sake of low computational burden, the problem of random errors contaminating the measurements is often considered to be zero-mean, white and Gaussian random variables. However, when a sensor fault occurs, the measurement errors no longer satisfy the Gaussian assumption and the results given by the system identification rapidly become unreliable. The present contribution is dedicated to the development of a diagnosis tool based on a Kalman filter whose structure is slightly modified in order to accommodate sensor malfunctions. The benefit in terms of the diagnostic reliability of the resulting tool is illustrated on several sensor faults that may be encountered on a current turbofan layout. [less ▲]

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See detailMethods
Richelle, Marc ULg; Lejeune, Helga ULg; Mantanus, H. et al

in Richelle, Marc; Lejeune, Helga (Eds.) Time in animal behaviour (1980)

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See detailMethods and means for metabolic engineering and improved product formation by micro-organisms
Rigali, Sébastien ULg; Titgemeyer, Fritz; van Wezel, Gilles

Patent (2007)

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See detailMethods for Estimating Areas under Receiver-Operating Characteristic Curves: Illustration with Somatic-Cell Scores in Subclinical Intramammary Infections
Detilleux, Johann ULg; Arendt, J.; Lomba, F. et al

in Preventive Veterinary Medicine (1999), 41(2-3), 75-88

The aim of this study was to demonstrate receiver-operating characteristic (ROC) methodology in the context of bovine intramammary infection (IMI). Quarter somatic cell scores (SCS) were available to ... [more ▼]

The aim of this study was to demonstrate receiver-operating characteristic (ROC) methodology in the context of bovine intramammary infection (IMI). Quarter somatic cell scores (SCS) were available to evaluate quarter IMI, and the final IMI diagnosis was made from milk bacteriologic cultures. Data consisted of 11,453 quarter-milk samples collected on 2084 clinically healthy cows located in 154 Belgian herds. Bacteriological analyses showed 16.2%, 7.2%, and 11.9% of quarters infected with coagulase-positive Staphylococcus spp., Streptococcus agalactiae, and coagulase-negative Staphylococcus spp., respectively. The ROC curve indicated all the combinations of sensitivity and specificity that quarter SCS was able to provide as a test to identify quarter IMI. Among parametric, semi-parametric, and non-parametric methods to estimate area under ROC curves, the parametric method seemed the least appropriate for analyzing SCS in this study. With the non-parametric method, the total area under the ROC curves showed quarter SCS could identify quarter IMI with an overall accuracy of 69%, 76%, and 59% for coagulase-positive Staphylococcus spp., S. agalactiae, and coagulase-negative Staphylococcus spp., respectively. Parametric and non-parametric statistical tests showed that overall SCS diagnostic capability was significantly (p<0.01) different from chance and was different (p<0.01) across the three bacteria. However, the SCS thresholds yielding the highest percentage of quarters correctly classified as infected (for the observed prevalence and for equal costs assigned to false-positive and false-negative results) were so high that they had no practical value. The major advantage of ROC analysis is the comprehensive description of the discrimination capacity of SCS for all possible choices of critical values. The major disadvantage is the dependency upon the gold standard used for the final diagnosis--but recent improvements of the methodology will correct the problem. [less ▲]

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See detailMethods for size classification of wood chips
Hartmann, Hans; Böhm, Thorsten; Daugbjerg Jensen, Peter et al

in Biomass & Bioenergy (2006)

Methods for size classification of wood chips were analysed in an international round robin using 13 conventional wood chip samples and two specially prepared standard samples, one from wood chips and one ... [more ▼]

Methods for size classification of wood chips were analysed in an international round robin using 13 conventional wood chip samples and two specially prepared standard samples, one from wood chips and one from hog fuel. The true size distribution of these two samples (according to length, width and height) had been determined stereometrically (reference method) using a digital calliper gauge and by weighing each of the about 7000 wood particles per sample. Five different horizontal and three rotary screening devices were tested using five different screen hole diameters (3.15, 8, 16, 45, 63 mm, round holes). These systems are compared to a commercially available continuously measuring image analysis equipment. The results show that among the devices of a measuring principle—horizontal and rotary screening—the results are quite comparable, while there is a severe incompatibility when distributions are determined by different measuring principles. Highest conformity with the reference values is given for measurements with an image analysis system, whereas for all machines with horizontal screens the median value of the size distribution only reached between one-third to half of the reference median value for the particle length distribution. These deviations can be attributed to a higher particle misplacement, which is particularly found in the larger fractions. Such differences decrease when the particle’s shape is more roundish (i.e. sphericity closer to one). The median values of length distributions from screenings with a rotary classifier are between the measurements from an image analysis and horizontal screening devices. [less ▲]

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See detailMethods for the preparation of bimetallic xerogel catalysts designed for chlorinated wastes processing
Lambert, Stéphanie ULg; Ferauche, Fabrice; Heinrichs, Benoît ULg et al

in Journal of Non-Crystalline Solids (2006), 352(26-27), 2751-2762

The aim of this work is to simplify and generalize the synthesis procedure of bimetallic supported catalysts by sol-gel process. For Pd-Ag/SiO2, co-gelled xerogels catalysts a number of synthesis ... [more ▼]

The aim of this work is to simplify and generalize the synthesis procedure of bimetallic supported catalysts by sol-gel process. For Pd-Ag/SiO2, co-gelled xerogels catalysts a number of synthesis procedures were compared: use of one or two specific alkoxides able to form a chelate with palladium and/or silver cations, reagent mixing in one or two steps, use of industrial grade chemicals instead of laboratory grade chemicals. The catalysts obtained are quite similar: same metal dispersion, same tailored morphology, same localization and accessibility of Pd-Ag alloy nanoparticles inside microporous silica, same activity and selectivity for hydrodechlorination of 1,2-dichloroethane into ethylene. For catalyst production at large scale the synthesis can be achieved in one step with 3-(2-aminoethyl)aminopropyltrimethoxysilane of industrial grade as chelating alkoxide, tetraethylorthosilicate (TEOS) of industrial grade and ethanol denatured with diethyl phthalate. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailMethods for Vitamin D measurement - analytical problems and clinical relevance
Cavalier, Etienne ULg

Conference (2010, March 05)

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See detailMethods in social cognition research
Dardenne, Benoît ULg

Scientific conference (1992)

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See detailMethods of clinical and biological assessment of rheumatoid arthritis
Malaise, Michel ULg; Franchimont, P.

in Scandinavian Journal of Rheumatology. Supplement (1987), 65

Inflammation has long been recognised as notoriously difficult to measure both in clinical practice and in the laboratory. Of all the cardinal features of inflammation, pain relief is really what the ... [more ▼]

Inflammation has long been recognised as notoriously difficult to measure both in clinical practice and in the laboratory. Of all the cardinal features of inflammation, pain relief is really what the patients want, and among disabled persons, rheumatic patients are the only ones who must cope with chronic pain. The rheumatologist, however, is also interested in other parameters that are thought to reflect improvement of the inflammatory process. The methods used to clinically assess rheumatoid arthritis (RA) should share the following four parameters: validity, sensitivity, reliability and simplicity. Unfortunately, at present, no single ideal method is capable of accurately reflecting disease activity in RA. The measurement of pain relief by the visual analogue scale, the determination of the Ritchie index and the duration of morning stiffness, plus patient assessment of global response should be enough to detect clinical activity of the drug in RA. If we are working with slow-acting drugs or so-called disease modifying antirheumatic drugs (DMARDs), it should be appropriate to include X-ray analysis and laboratory tests in the evaluation. A reduction in the number of fresh erosions and/or the healing of present erosions can give reliable information on the capacity of the drug to really modify the course of the disease. At present, measurement of the erythrocyte sedimentation rate and of acute phase serum proteins seems to offer the best available assessment during early weeks of therapy. The other biological tests are of limited value in reflecting or predicting a beneficial clinical response to DMARDs. [less ▲]

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See detailMethods of sensory evaluation of odour and 50 m3 test facility at Arlon laboratory
Romain, Anne-Claude ULg; Nicolas, Jacques ULg; Degraeve, Ch

Diverse speeche and writing (2008)

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See detailMethods of sputum processing for cell counts, immunocytochemistry and in situ hybridisation
Efthimiadis, A.; Spanevello, A.; Hamid, Q. et al

in European Respiratory Journal (2002), 20(Suppl. 37), 19-23

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See detailMethods to Increase the Robustness of Finite-Volume Flow Models in Thermodynamic Systems
Quoilin, Sylvain ULg; Bell, Ian ULg; Desideri, Adriano ULg et al

in Energies (2014), 7(3), 1621-1640

This paper addresses the issues linked to simulation failures during integration in finite-volume flow models, especially those involving a two-phase state. This kind of model is particularly useful when ... [more ▼]

This paper addresses the issues linked to simulation failures during integration in finite-volume flow models, especially those involving a two-phase state. This kind of model is particularly useful when modeling 1D heat exchangers or piping, e.g., in thermodynamic cycles involving a phase change. Issues, such as chattering or stiff systems, can lead to low simulation speed, instabilities and simulation failures. In the particular case of two-phase flow models, they are usually linked to a discontinuity in the density derivative between the liquid and two-phase zones. In this work, several methods to tackle numerical problems are developed, described, implemented and compared. In addition, methods available in the literature are also implemented and compared to the proposed approaches. Results suggest that the robustness of the models can be significantly increased with these different methods, at the price of a small increase of the error in the mass and energy balances. [less ▲]

Detailed reference viewed: 39 (12 ULg)