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See detailComparing traffic engineering objective functions
Balon, Simon ULg; Skivée, Fabian; Leduc, Guy ULg

in CoNext 2005 - Student Workshop (2005, October)

We compare and evaluate how well-known and novel network-wide objective functions for Traffic Engineering (TE) algorithms fulfil TE requirements. To compare the objective functions we model the TE problem ... [more ▼]

We compare and evaluate how well-known and novel network-wide objective functions for Traffic Engineering (TE) algorithms fulfil TE requirements. To compare the objective functions we model the TE problem as a linear program and solve it to optimality, thus finding for each objective function the best possible target of any heuristic TE algorithm. Our first results suggest that they can give quite different results. [less ▲]

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See detailComparing vertical ground heat exchanger models
Bertagnolio, Stéphane ULg; Bernier, Michel; Kummert, Michaël

in Journal of Building Performance Simulation [=JBPS] (2012)

The main objective of this article is to establish a set of test cases for analytical verification and inter-model comparison of vertical ground heat exchanger (GHX) models used in building simulation ... [more ▼]

The main objective of this article is to establish a set of test cases for analytical verification and inter-model comparison of vertical ground heat exchanger (GHX) models used in building simulation programs. Several test cases are suggested. They range from steady-state heat rejection in a single borehole to varying hourly loads with relatively large yearly thermal imbalance in multiple borehole configurations. The usefulness of the proposed test cases is illustrated with different GHX models. This comparison exercise has shown that analytical one-dimensional (1D) models compare favourably well with three-dimensional (3D) models for relatively short-simulation periods, where axial effects are not significant. Cyclic heat rejection/collection tests proved to be useful to characterize the accuracy and the computational performance of different load aggregation algorithms. Finally, different spatial superposition methods have been compared for various bore field sizes and configurations and various loads. [less ▲]

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See detailA comparison study of image appraisal tools for electrical resistivity tomography
Caterina, David ULg; Beaujean, Jean ULg; Robert, Tanguy ULg et al

in Near Surface Geophysics (2013)

To date, few studies offer a quantitative comparison of the performance of image appraisal tools. Moreover, there is no commonly accepted methodology to handle them even though it is a crucial aspect for ... [more ▼]

To date, few studies offer a quantitative comparison of the performance of image appraisal tools. Moreover, there is no commonly accepted methodology to handle them even though it is a crucial aspect for reliable interpretation of geophysical images. In this study, we compare quantitatively different image appraisal indicators to detect artefacts, estimate depth of investigation, address parameters resolution and appraise ERT-derived geometry. Among existing image appraisal tools, we focus on the model resolution matrix (R), the cumulative sensitivity matrix (S) and the depth of investigation index (DOI) that are regularly used in the literature. They are first compared with numerical models representing different geological situations in terms of heterogeneity and scale and then used on field data sets. The numerical benchmark shows that indicators based on R and S are the most appropriate to appraise ERT images in terms of the exactitude of inverted parameters, DOI providing mainly qualitative information. In parallel, we test two different edge detection algorithms – Watershed’s and Canny’s algorithms – on the numerical models to identify the geom-etry of electrical structures in ERT images. From the results obtained, Canny’s algorithm seems to be the most reliable to help practitioners in the interpretation of buried structures. On this basis, we propose a methodology to appraise field ERT images. First, numerical bench¬mark models representing simplified cases of field ERT images are built using available a priori information. Then, ERT images are produced for these benchmark models (all simulated acquisition and inversion parameters being the same). The comparison between the numerical benchmark mod¬els and their corresponding ERT images gives the errors on inverted parameters. These discrepan¬cies are then evaluated against the appraisal indicators (R and S) allowing the definition of threshold values. The final step consists in applying the threshold values on the field ERT images and to validate the results with a posteriori knowledge. The developed approach is tested successfully on two field data sets providing important information on the reliability of the location of a contamina¬tion source and on the geometry of a fractured zone. However, quantitative use of these indicators remains a difficult task depending mainly on the confidence level desired by the user. Further research is thus needed to develop new appraisal indicators more suited for a quantitative use and to improve the quality of inversion itself. [less ▲]

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See detailA comparison among portal lactate, intramucosal sigmoid pH, and Delta CO2 (Paco(2) regional Pco(2)) as indices of complications in patients undergoing abdominal aortic aneurysm surgery
Donati, A.; Cornacchini, O.; Loggi, S. et al

in Anesthesia and Analgesia (2004), 99(4), 1024-1031

Our aim in this observational, prospective, noncontrolled study was to detect, in 29 patients who underwent abdominal aortic aneurysm (AAA) surgery, correlations between the incidence of postoperative ... [more ▼]

Our aim in this observational, prospective, noncontrolled study was to detect, in 29 patients who underwent abdominal aortic aneurysm (AAA) surgery, correlations between the incidence of postoperative organ failure and intraoperative changes in arterial and portal blood lactate; changes in intramucosal sigmoid pH (pHi); differences between sigmoid P-CO2 and arterial P-CO2 (DeltaCO(2)); and hemoglobin (Hb). Hb, arterial blood lactate concentrations, pHi, and DeltaCO(2) (air tonometry) were recorded at the start of anesthesia (T0), before aorta clamping (T1), 30 minutes after clamping (T2), and at the end of surgery (T3). Portal venous lactate concentrations were recorded at T1 and T2. Patients were stratified into two groups: group A patients had no postoperative organ failure, and group B patients had one or more organ failures. As compared with group A (n = 16), group B patients (n = 13) had a lower pHi value at T2 and T3 and a higher DeltaCO(2) at T3. A pHi value of <7.15 was a predictor of organ failure, with a sensitivity of 92.3%, a specificity of 68.8%, and positive and negative predictive values of 70.6% and 91.7%, respectively, whereas a DeltaCO(2) value of >28 mm Hg predicted later organ failure with a sensitivity of 92.3%, a specificity of 62.5%, and positive and negative predictive values of 66.6% and 90.9%, respectively. Portal venous lactate concentrations were larger in group B at T2 (P<0.001), and an increase greater than or equal to5 g/dL predicted later postoperative organ failure with a sensitivity of 92.3%, a specificity of 100%, and positive and negative predictive values of 100% and 94.1%, respectively. The comparison of the receiving operator characteristic curves to test the discrimination of each variable and the logistic regression analysis revealed that the increase in portal lactate was the best predictor for the development of postoperative organ failure. Hb concentration was significantly smaller in group B at T0 (13.8 +/- 1.0 g/dL versus 12.2 +/- 2.2 g/dL) and T2 (10.9 +/- 1.2 g/dL versus 9.1 +/- 1.9 g/dL). In conclusion, both pHi and DeltaCO(2) are reasonably sensitive prognostic indices of organ failures after AAA surgery, but they are less specific and accurate than portal venous lactate. [less ▲]

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See detailComparison and combination of spectroscopic techniques for the detection of counterfeit medicines
Sacré, Pierre-Yves ULg; Deconinck, Eric; De Beer, Thomas et al

Poster (2010, September 23)

During this study, Fourier transform infrared spectroscopy (FT-IR), near infrared spectroscopy (NIR) and Raman spectroscopy were applied to 55 samples of counterfeit and imitations of Viagra® and 39 ... [more ▼]

During this study, Fourier transform infrared spectroscopy (FT-IR), near infrared spectroscopy (NIR) and Raman spectroscopy were applied to 55 samples of counterfeit and imitations of Viagra® and 39 samples of counterfeit and imitations of Cialis®. The aim of the study was to investigate which of these techniques and associations of them were the best for discriminating genuine from counterfeit and imitation samples. Only the regions between 1800-400 cm-1 and 7000-4000 cm-1 were used for FT-IR and NIR spectroscopy respectively. Partial Least Square analysis has been used to allow the detection of counterfeit and imitation tablets. It is shown that for the Viagra® samples, the best results were provided by a combination of FT-IR and NIR spectroscopy. On the other hand, the best results for the Cialis® samples were provided by the combination of NIR and Raman spectroscopy (1400-1190 cm-1). These techniques permitted a clear discrimination between genuine and counterfeit or imitation samples but also the distinction of clusters among illegal samples. This might be interesting for forensic investigations by authorities. [less ▲]

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See detailComparison and combination of spectroscopic techniques for the detection of counterfeit medicines
Sacré, Pierre-Yves ULg; Deconinck, Eric; De Beer, Thomas et al

in Journal of Pharmaceutical & Biomedical Analysis (2010), 53

During this study, Fourier transform infrared spectroscopy (FT-IR), near infrared spectroscopy (NIR) and Raman spectroscopy were applied to 55 samples of counterfeit and imitations of Viagra® and 39 ... [more ▼]

During this study, Fourier transform infrared spectroscopy (FT-IR), near infrared spectroscopy (NIR) and Raman spectroscopy were applied to 55 samples of counterfeit and imitations of Viagra® and 39 samples of counterfeit and imitations of Cialis®. The aim of the study was to investigate which of these techniques and associations of them were the best for discriminating genuine from counterfeit and imitation samples. Only the regions between 1800-400 cm-1 and 7000-4000 cm-1 were used for FT-IR and NIR spectroscopy respectively. Partial Least Square analysis has been used to allow the detection of counterfeit and imitation tablets. It is shown that for the Viagra® samples, the best results were provided by a combination of FT-IR and NIR spectroscopy. On the other hand, the best results for the Cialis® samples were provided by the combination of NIR and Raman spectroscopy (1400-1190 cm-1). These techniques permitted a clear discrimination between genuine and counterfeit or imitation samples but also the distinction of clusters among illegal samples. This might be interesting for forensic investigations by authorities. [less ▲]

Detailed reference viewed: 59 (14 ULg)
See detailComparison and complementary of the methods
Baeten, Vincent; Vermeulen, Ph.; Berben, Gilbert et al

in STRATFEED - Strategies and methods to detect and quantify mammalian tissues in feedingstuffs. (2005)

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See detailComparison and impact of waste heat recovery technologies on passenger car fuel consumption on a normalized driving cycle
Legros, Arnaud ULg; Guillaume, Ludovic ULg; Diny, Mouad et al

in Energies (2014)

The purpose of this article was to compare different waste heat recovery system technologies designed for automotive applications. A complete literature review is done and results in two comparative ... [more ▼]

The purpose of this article was to compare different waste heat recovery system technologies designed for automotive applications. A complete literature review is done and results in two comparative graphs. In the second part, simulation models are built and calibrated in order to assess the fuel consumption reduction that can be achieved on a real driving cycle. The strength of this article is that the models are calibrated using actual data. Finally, those simulations results are analyzed and the Rankine cycle and turbocompound are the two most profitable solutions. However the simulations of the turbocompound shows its limitations because the impact on the exhaust pressure drop is not taken into account in the assessment of the car fuel consumption. Fuel reduction of up to 6% could be achieved, depending on the driving cycle and the waste heat recovery technology. [less ▲]

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See detailCOMPARISON AND MOLECULAR CHARACTERIZATION OF ANIMAL AND HUMAN CLOSTRIDIUM DIFFICILE STRAINS
Rodriguez Diaz, Cristina ULg; Taminiau, Bernard ULg; Korsak Koulagenko, Nicolas ULg et al

Poster (2014, May 07)

The main objective of this study was to characterize and compare animal and human C. difficile strains with respect to the PCR-ribotype and the antibiotic resistance. Multilocus sequence typing analysis ... [more ▼]

The main objective of this study was to characterize and compare animal and human C. difficile strains with respect to the PCR-ribotype and the antibiotic resistance. Multilocus sequence typing analysis (MLST) was performed in order to study clonal relationships of the isolates. [less ▲]

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See detailComparison and validation of heat stress indices in experimental studies
Mairiaux, Philippe ULg; Malchaire, Jacques

in Ergonomics (1995), 38(1), 58-72

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See detailComparison between 3 sources of dietary fibre in dog's diet. Effects on digestibility and on plasma metabolites
Diez, Marianne ULg; Marche, Christian; Hornick, Jean-Luc ULg et al

in Proceedings of the 4th European Society of Veterinary Internal Medecine. Annual Congress (1994)

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See detailCOMPARISON BETWEEN 4 METHODS TO MEASURE GLUCOSINOLATES IN RAPESEEDS
Wathelet, Jean-Paul ULg; Cwilowski, M.; Severin, M. et al

in Revue Française des Corps Gras (1988), 35(4), 177-179

Total glucosinolate content in rapeseeds cultivated in France. Germany. Denmark, United Kingdom and Belgium has been determined by high performance liquid chromatography (HPLC), gas liquid chromatography ... [more ▼]

Total glucosinolate content in rapeseeds cultivated in France. Germany. Denmark, United Kingdom and Belgium has been determined by high performance liquid chromatography (HPLC), gas liquid chromatography (GLC),measurement of glucose released by myrosinase and Pd glucosinolate complex after purification on an ion exchange column. Methods are well correlated. Glucose method and HPLC give similar results r: O.995, bias: O.055 µM/gr). ln most cases. GLC results are lower than HPLC (r: O.995, bias: - 2.482 µM/gr). Palladium method gives systematically higher results than HPLC (t: 0.99O, bias: 6.763 µM/gr). [less ▲]

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See detailComparison between 4 processing techniques of maize in dogs's diet: Effects on digestibility and on plasma metabolites
Diez, Marianne ULg; Baldwin, Paule ULg; Clinquart, Antoine ULg et al

in Delfino, A. (Ed.) Proceedings of the 17th World Small Animal Veterinary Association. (1992)

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See detailComparison between a commercial kibble and hatchling chickens as diets for adult ferrets (Mustela putorius furo) : effects on digestibility coefficients and blood parameters
Piazza, Stéphanie; Robaye, Vincent ULg; Lhoest, Estelle et al

in Iben, C. (Ed.) Proceedings of the 12th ESVCN Congress (2008)

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See detailComparison between a high chromium steel and a semi HSS grades used as work rolls in the roughing stands of a hot strip mill
Tchuindjang, Jérôme Tchoufack ULg; Lecomte-Beckers, Jacqueline ULg

in Proceedings of The 10th International Conference on Steel Rolling (10th ICSR) (2010, September)

Two alloys grades for work rolls used in the roughing stand of Hot Strip Mill (HSM) were compared. The first grade known as High Chromium Steel (HCS) is actually the alloy widely used for such an ... [more ▼]

Two alloys grades for work rolls used in the roughing stand of Hot Strip Mill (HSM) were compared. The first grade known as High Chromium Steel (HCS) is actually the alloy widely used for such an application, while the second one known as semi-High Speed Steel (semi-HSS) is the new grade developed to improve overall properties of the work roll in the roughing stands of the HSM. In the present work, the new semi-HSS grade is studied starting from 3 chemical compositions closed one to another, the variation in the alloying elements being intended to assess, on one hand the effect of a light increase of the carbon content, and on the other hand the influence of the addition of a strong MC carbide forming element. The comparison of HCS and semi-HSS grades involved many fields. Regarding the metallurgical aspect, such a comparison led to the enhancement of the solidification range, the crystallization behavior and the microstructure in the as-cast condition for both grades. Heat treatment behavior of both grades was also investigated and optimal parameters leading to the homogenization of the alloy composition within the deepness of the roll were found. Furthermore, hot corrosion behavior and performances of the work rolls in service were compared. Various techniques were used in order to characterize both grades, such as Differential Thermal Analysis (to determine phase transformations temperatures, the crystallization behavior and the interval of solidification), hardness measurements, optical microscopy, scanning electron microscopy associated with energy dispersive X ray spectroscopy (to determine the nature and the composition of phases, especially matrix and carbides). Finally micro-macro relations between the nature of the microstructure and the properties of HCS and semi-HSS rolls grades in service conditions could be established. [less ▲]

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See detailComparison between active and passive surveillance within the Network of Epidemiological Surveillance of Animal Diseases in Chad (REPIMAT)
Ouagal, M.; Hendrikx, P.; Saegerman, Claude ULg et al

in Acta Tropica (2010), 116(2), 147-151

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See detailComparison between Alprazolam and Hydroxyzine for Oral Premedication
Franssen, Colette ULg; Hans, Pol ULg; Brichant, Jean-François ULg et al

in Canadian Journal of Anaesthesia = Journal Canadien d'Anesthésie (1993), 40(1), 13-7

The safety and efficacy of alprazolam and hydroxyzine administered orally as surgical premedicants were compared in a double-blind controlled study. Sixty-five patients were given either alprazolam 1 mg ... [more ▼]

The safety and efficacy of alprazolam and hydroxyzine administered orally as surgical premedicants were compared in a double-blind controlled study. Sixty-five patients were given either alprazolam 1 mg or hydroxyzine 75 mg, one to two hours before surgery. Anxiety was assessed by both the patient and the anaesthetist, the patient using a visual analogue scale, the anaesthetist employing both analogue and ordinal ratings. Sedation was assessed by the anaesthetist only, using the same two methods. Amnesia was appraised with a simple memory test. Safety was assessed by recording adverse effects and measuring haemodynamic variables. Premedication with alprazolam produced a modest reduction in anxiety (28%) (P < 0.01) while hydroxyzine had no detectable effect. The comparison of the sedation level and of the memory test revealed no difference between the two premedicants. Minor side effects were only observed in the hydroxyzine group. Changes in blood pressure were more pronounced in the hydroxyzine group. This study shows that alprazolam and hydroxyzine are safe and efficient oral premedicants. However, alprazolam is preferable to hydroxyzine in terms of anxiolytic and adverse effects. [less ▲]

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See detailComparison between analytical and optimal control techniques in the differential drag based rendez-vous
Dell'Elce, Lamberto ULg; Kerschen, Gaëtan ULg

in Proceedings of the 5th International Conference on Spacecraft Formation Flying Missions & Technologies (2013, May 29)

The focus of this study is on differential drag for propellantless satellite rendez-vous. This technique is particularly attractive for low-Earth-orbit small satellites for which stringent weight ... [more ▼]

The focus of this study is on differential drag for propellantless satellite rendez-vous. This technique is particularly attractive for low-Earth-orbit small satellites for which stringent weight constraints apply. Most existing contributions are based on bang-bang strategies, which may be difficult to implement in practice. This is why the present paper proposes a novel strategy integrating pseudospectral optimal control for maneuver planning and model predictive control for dealing with uncertainties and unmodeled dynamics. One important advantage of this methodology is that it can naturally account for attitude dynamics and constraints, which, in turn, paves the way for the practical realization of differential drag-based rendez-vous. A realistic scenario involving two nanosatellites of the QB50 constellation is considered to illustrate and validate the proposed developments. In addition, a comparison of this numerical technique with an existing analytic solution is carried out, and their respective pros and cons are discussed. [less ▲]

Detailed reference viewed: 16 (8 ULg)