Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailInvestigating word recognition in intercomprehension: methods and findings
Möller, Robert ULg; Zeevaert, Ludger ULg

in Linguistics (in press), 53(2),

Detailed reference viewed: 68 (15 ULg)
Full Text
Peer Reviewed
See detailInvestigation and reduction of discretization Variance in decision tree induction
Geurts, Pierre ULg; Wehenkel, Louis ULg

in Proceedings of ECML 2000, European Conference on Machine Learning (2000)

This paper focuses on the variance introduced by the discretization techniques used to handle continuous attributes in decision tree induction. Different discretization procedures are first studied ... [more ▼]

This paper focuses on the variance introduced by the discretization techniques used to handle continuous attributes in decision tree induction. Different discretization procedures are first studied empirically, then means to reduce the discretization variance are proposed. The experiments shows that discretization variance is large and that it is possible to reduce it significantly without notable computational costs. The resulting variance reduction mainly improves interpretability and stability of decision trees, and marginally their accuracy. [less ▲]

Detailed reference viewed: 7 (1 ULg)
Full Text
See detailInvestigation biologique des allergies alimentaires chez l'enfant
GADISSEUR, Romy ULg

Conference (2011, October 13)

Detailed reference viewed: 26 (4 ULg)
Peer Reviewed
See detailInvestigation by testing of the structural response of semi-rigid joints
Jaspart, Jean-Pierre ULg; Maquoi, René ULg

in proceedings of the RILEM Workshop on "Needs in testing metals" (1990)

Detailed reference viewed: 13 (1 ULg)
Full Text
See detailInvestigation et modélisation des tensions circonférentielles en simulation méridienne
Thomas, Jean-Philippe ULg

Master of advanced studies dissertation (2008)

The computation time and the extraction of useful information remain severe drawbacks to systematic use of modern 3D Navier-Stokes codes in a design procedure of multistage turbomachines. That explains ... [more ▼]

The computation time and the extraction of useful information remain severe drawbacks to systematic use of modern 3D Navier-Stokes codes in a design procedure of multistage turbomachines. That explains why throughflow simulation is still widely used at industrial scale. The main limitation of throughflow is however the need for empirical models to reproduce blade-flow interactions and major 3D flow features. As an alternative, Adamczyk (1984) proposed three averaging operators (ensemble, time and passage) that lead to the average-passage model, linking the unsteady turbulent flow field to a steady flow field in a typical blade passage. This model involves additional terms that respectively bring back the mean effect of turbulence, deterministic unsteadiness and aperiodicity on the mean periodic flow. These terms need to be modelled; it is the closure problem. Harmonic closure, which consists in solving a linearized perturbation system in the frequency domain, revealed to be an efficient method to approximate deterministic stresses (He and Ning, 1998, Stridh, 2005, Vilmin, 2006). A fourth averaging can be performed, a circumferential averaging, giving rise to the throughflow model. Additional terms appear: the so-called circumferential stresses. It has been proven that these terms play an important role in the description of the flow (Jennions, 1986, Perrin, 1995), being at least as considerable as deterministic stresses. Introducing these terms in a throughflow simulation allows to reproduce the averaged 3D steady flow field (Simon, 2007). The purpose of this work is to investigate how far empiricism could be reduced by using the averaged-passage equations of Adamczyk, combined with a harmonic closure strategy. To that aim, in the first part of the work, results of a computation performed with a steady three-dimensional Navier-Stokes code are used to calculate the circumferential stresses. The importance of the latter to bring back the mean eff ect of circumferential non-uniformities, linked to 3D phenomena, is illustrated by injecting them into a throughfow simulation. Then the ability of truncated Fourier series to reproduce the flow and its level of non-uniformity in the core flow and near the hub and shroud walls is detailed. It is finally shown that the harmonic approximated stresses can lead to a good reproduction of local 3D flow features in throughflow simulation and to a better accuracy. In the second part of this work it is proposed to adapt the "Nonlinear Harmonic" method to the throughflow model, where the main non-linear system would be the common throughflow equations and the auxiliary systems would give access to a mean high order information; the circumferential stresses. On the way to the adaptation of this technique to the throughflow model, the work shows that a reformulation of the effect of the blades is needed. The latter cannot appear anymore as numerical local explicit impermeability conditions that could not be supported by Fourier series, needing a continuous circumferential evolution of the flow. To get rid of this issue, the blade effect is replaced by a smooth force field as in the "Immersed Boundary Method" of Peskin. A simple example of an inviscid flow around a cylinder illustrates the preceding developments, coupling the "Nonlinear Harmonic Method" to the "Immersed Boundary Method" in a throughflow model, to bring back the mean e ffect of the circumferential non uniformities into the meridional flow. [less ▲]

Detailed reference viewed: 67 (7 ULg)
Full Text
Peer Reviewed
See detailAn Investigation into the Influence of External Walls Reflectivity on the Indoor Daylight Availability in Desert Climates
Hegazy, Mohamed Amer; Attia, Shady ULg

in Conference Proceedings: Building Simulation and Optimization 2014 (2014, June)

Hot arid climates are characterized by clear sunny sky most of the year time. Such climates affects the urban morphology, which requires sometimes dense urban fabric. Narrow streets have significant ... [more ▼]

Hot arid climates are characterized by clear sunny sky most of the year time. Such climates affects the urban morphology, which requires sometimes dense urban fabric. Narrow streets have significant effect on the amount of daylight permeating indoor residential zones, which may have a negative or positive effect on the overall visual performance. This paper studies the quantitative effect of using different Façade reflectivity ratios, under different street widths, on the indoor daylight autonomy. The researcher performed a parametric analysis using DIVA for Rhino simulation tool on a hypothetical residential building unit with various window ratios facing neighbouring buildings. Four main orientations were examined under different urban contexts and wall reflectivity. This paper aims to measure daylight autonomy and address possible strategies and solutions to achieve better daylighting that can be used by architects at early design stages of housing developments in the desert climates. [less ▲]

Detailed reference viewed: 69 (3 ULg)
Full Text
Peer Reviewed
See detailINVESTIGATION OF A LOCAL INDICATOR OF VOLTAGE EMERGENCY IN THE HELLENIC INTERCONNECTED SYSTEM
Vournas, Costas; Sakellaridis, N.; Christoforidis, George et al

(2008, July)

In this paper we evaluate the performance of a proposed local indicator of voltage emergency for a simulated unstable contingency of the Hellenic Intercon-nected System identified through the on-line VSA ... [more ▼]

In this paper we evaluate the performance of a proposed local indicator of voltage emergency for a simulated unstable contingency of the Hellenic Intercon-nected System identified through the on-line VSA applica-tion for the summer peak of 2007. The effect of deadbands and tap range limits in delaying the emergency alarm issued is examined. The area mostly affected by the insta-bility is identified through the proposed algorithm and a simple load-shedding scheme sufficient to avert the collapse is suggested. [less ▲]

Detailed reference viewed: 65 (3 ULg)
Full Text
Peer Reviewed
See detailInvestigation of advanced materials for fusion alpha particle diagnostics
Bonheure, G.; Van Wassenhove, G.; Hult, M. et al

in Fusion Engineering & Design (2013)

Fusion alpha particle diagnostics for ITER remain a challenging task. Standard escaping alpha particle detectors in present tokamaks are not applicable to ITER and techniques suitable for fusion reactor ... [more ▼]

Fusion alpha particle diagnostics for ITER remain a challenging task. Standard escaping alpha particle detectors in present tokamaks are not applicable to ITER and techniques suitable for fusion reactor conditions need further research and development [1,2]. The activation technique is widely used for the characterization of high fluence rates inside neutron reactors. Tokamak applications of the neutron activation technique are already well developed [3] whereas measuring escaping ions using this technique is a novel fusion plasma diagnostic development. Despite low alpha particle fluence levels in present tokamaks, promising results using activation technique combined with ultra-low level gamma-ray spectrometry [4] were achieved before in JET [5,6]. In this research work, we use new advanced detector materials. The material properties beneficial for alpha induced activation are (i) moderate neutron cross-sections (ii) ultra-high purity which reduces neutron-induced background activation and (iii) isotopic tailoring which increases the activation yield of the measured activation product. Two samples were obtained from GERDA[7], an experiment aimed at measuring the neutrinoless double beta decay in 76Ge. These samples, made of highly pure (9 N) germanium highly enriched to 87% in isotope Ge-76, were irradiated in real D-D fusion plasma conditions inside the TEXTOR tokamak. Comparison of the calculated and the experimentally measured activity shows good agreement. Compared to previously investigated high temperature ceramic material [8], this candidate detector offers better prospects for signal to background S/B ratio, energy resolution and particle selectivity due to a unique alpha particle signature. Applicability to ITER is discussed. Finally, research needs for further development of this diagnostic technique are outlined. © 2013. [less ▲]

Detailed reference viewed: 51 (12 ULg)
See detailInvestigation of African plants traditionally used to treat malaria
Frederich, Michel ULg

Conference (2012, July 05)

Detailed reference viewed: 35 (16 ULg)
Peer Reviewed
See detailInvestigation of airway reactivity by barometric whole body plethysmography in cats with spontaneous bronchial disease
Bernaerts, Frederique ULg; Merveille, Anne-Christine ULg; Bolognin, M. et al

in 24th Symposium of the Veterinary Comarative Respiratory Society - Jena, Allemagne 8-10 octobre 2006 (2006, October)

Detailed reference viewed: 8 (1 ULg)
Full Text
See detailInvestigation of anaerobic digestion in a two-stage bioprocess producing hydrogen and methane
Hiligsmann, Serge ULg; Hamilton, Christopher ULg; Beckers, Laurent ULg et al

Conference (2010, November 17)

Hydrogen has received wide attention in the last decades as a clean energy vector. The major advantage of energy generation from hydrogen is the near-zero carbon emissions, since the utilization of ... [more ▼]

Hydrogen has received wide attention in the last decades as a clean energy vector. The major advantage of energy generation from hydrogen is the near-zero carbon emissions, since the utilization of hydrogen, either via combustion or via fuel cells, results in pure water. Recently, there has been increasing interest on the biological production of hydrogen gas from renewable biomass such as carbohydrates from agriculture or agro-food industries. This specific anaerobic digestion is called dark fermentation and is involved in the classic anaerobic digestion producing methane. Indeed, in a two-step process, i.e. when acido- and aceto-genesis are carried out in a different bioreactor than methanogenesis, it is feasible to generate separated biogas flows containing either H2 or CH4 depending on specific operating parameters. This paper deals with the comparison of the first stage performances whether operated in optimum conditions for H2 production with a mixed culture or a pure Clostridium butyricum strain. Hydrogen yields of about 1.75 and 2.3 mol H2/mol glucose were achieved respectively. The metabolites, mainly acetate and butyrate, contained in the spent medium were efficiently converted to methane in a second anaerobic digester with a methane yield of about 170 ml/g COD initially fed in the first stage. [less ▲]

Detailed reference viewed: 120 (33 ULg)
Full Text
Peer Reviewed
See detailInvestigation of application sharing systems for teaching purposes in engineering disciplines
Burger, C.; Papakosta, S.; Bullinger, Eric ULg et al

in 4th Int. Conf. New Educational Environment (2002)

Detailed reference viewed: 6 (0 ULg)
Full Text
Peer Reviewed
See detailInvestigation of automatic memory during general anesthesia for elective surgery using the process dissociation procedure
Willems, Sylvie ULg; Iselin-Chaves, Irène A.; Jermann, Françoise J. et al

in Anesthesiology (2005), 103

Background: This prospective study evaluated memory function during general anesthesia for elective surgery and its relation to depth of hypnotic state. The authors also compared memory function in ... [more ▼]

Background: This prospective study evaluated memory function during general anesthesia for elective surgery and its relation to depth of hypnotic state. The authors also compared memory function in anesthetized and nonanesthetized subjects. Methods: Words were played for 70 min via headphones to 48 patients (aged 18–70 yr) after induction of general anesthesia for elective surgery. Patients were unpremedicated, and the anesthetic regimen was free. The Bispectral Index (BIS) was recorded throughout the study. Within 36 h after the word presentation, memory was assessed using an auditory word stem completion test with inclusion and exclusion instructions. Memory performance and the contribution of explicit and implicit memory were calculated using the process dissociation procedure. The authors applied the same memory task to a control group of nonanesthetized subjects. Results: Forty-seven patients received isoflurane, and one patient received propofol for anesthesia. The mean ( SD) BIS was 49 9. There was evidence of memory for words presented during light (BIS 61–80) and adequate anesthesia (BIS 41–60) but not during deep anesthesia (BIS 21–40). The process dissociation procedure showed a significant implicit memory contribution but not reliable explicit memory contribution (mean explicit memory scores 0.05 0.14, 0.04 0.09, and 0.05 0.14; mean automatic influence scores 0.14 0.12, 0.17 0.17, and 0.18 0.21 at BIS 21–40, 41–60, and 61–80, respectively). Compared with anesthetized patients, the memory performance of nonanesthetized subjects was better, with a higher contribution by explicit memory and a comparable contribution by implicit memory. Conclusion: During general anesthesia for elective surgery, implicit memory persists even in adequate hypnotic states, to a comparable degree as in nonanesthetized subjects. [less ▲]

Detailed reference viewed: 55 (8 ULg)
Full Text
Peer Reviewed
See detailInvestigation of biological markers to evaluate the adaptation of the newborn Belgian Blue calf to the extrauterine life. A pilot study.
Ronzoni, Anna ULg; Theron, Léonard ULg; De Marchin, Emmanuelle et al

in Dalin, Göran (Ed.) 15th International Conference on Production Diseases in Farms Animals, Book of Abstracts (2013, June)

Adaptation to extrauterine life and immunity transfer at calving are more at stake when dealing with highly productive breeds such as the Belgian Blue Cattle Breed (BBCB). The purpose of the present pilot ... [more ▼]

Adaptation to extrauterine life and immunity transfer at calving are more at stake when dealing with highly productive breeds such as the Belgian Blue Cattle Breed (BBCB). The purpose of the present pilot study was to evaluate different blood markers, from the birth to the first week of life in BBCB calves, in order to investigate fundamental aspects of the adaptation to the extrauterine life as passive immunity transfer and early energy metabolism. Eighty calves coming from 10 different farms located in Wallonia (Belgium) were enrolled. A clinical examination was performed to verify viability and maturity at birth. Blood samples were collected at birth, day 1 and day 3 to 7. Passive immunity transfer analysis included serum and colostrum immunoglobulin G (IgG) concentration, and plasmatic selenium concentration (Se). Glycemia, serum insulin and cortisol concentration have been considered for the energy metabolism analysis. The data collected were statistically analysed using logistic regression and unpaired t-test. All calves were born alive, viable and mature by caesarean section. Mortality rate was 0% at one week and 5% at three months. Only 33% of calves had an IgG concentration >16g/L after one week of age, while only 34% of colostra had an IgG concentration >70g/L. Glycemia and serum insulin concentration at birth were significantly lower than other breeds, and plasmatic selenium concentration were coherent with low supplemented dams. We compared calves across IgG concentration classes (>16 g/L vs <16g/L). The crosssectional analysis of the risk of FPT when given low IgG concentration colostra has shown a non significant odd ratio (OR 1,058 and 0,39116 g/L) (p<0,001). No significant difference has been shown between cortisol and glycemia (p=0,3) nor insulin and glycemia (p=0,2) at birth. These data suggest a significant difference in BBCB calves on several metabolic markers, but they also revealed that immunity transfer and micronutrition of pregnant hyper-productive dams remain a challenge in modern farms. [less ▲]

Detailed reference viewed: 53 (21 ULg)
Peer Reviewed
See detailInvestigation of blood oxidant/antioxidant markers in healthy competition horses : effect of discipline and gender.
Kirschvink, N.; De Moffarts, Brieuc; Farnir, Frédéric ULg et al

in 7th International Conference on Equine Exercise Physiology (2006)

Detailed reference viewed: 17 (5 ULg)
Full Text
Peer Reviewed
See detailInvestigation of blood oxidant/antioxidant markers in healthy competition horses of different breeds
Kirschvink, Nathalie; de Moffarts, Brieuc; Farnir, Frédéric ULg et al

in Equine Veterinary Journal. Supplement (2006), 36

REASONS FOR PERFORMING STUDY: There is increasing evidence that the equine athlete is exposed to exercise-induced changes of its oxidant/antioxidant balance and antioxidant supplementation is frequently ... [more ▼]

REASONS FOR PERFORMING STUDY: There is increasing evidence that the equine athlete is exposed to exercise-induced changes of its oxidant/antioxidant balance and antioxidant supplementation is frequently recommended. However, it is unknown whether there is a specific need for antioxidants according to performance, breed, gender or age. OBJECTIVES: To assess whether breed-, gender- and age-related differences of blood oxidant/antioxidant markers occur in competition horses. METHODS: Healthy horses (n = 493) underwent oxidant/ antioxidant blood marker determination. Vitamin E, lipophilic antioxidant capacity (ACL), ascorbic acid (AA), glutathione (GSH, GSSG), gluthione peroxidase (GPx), superoxide dismutase (SOD), selenium (Se), copper (Cu), zinc (Zn), lipid peroxides (Pool), oxidised proteins (Protox) were determined, as well as magnesium (Mg), creatine phosphokinase (CPK), lactate dehydrogenase (LDH), packed cell volume (PCV) and haemoglobin (Hb). A mixed linear model assessed the effect of breed, gender and age category. P<0.05 was considered significant. RESULTS: Thoroughbreds showed the highest values of vitamin E, ACL, GPx, PCV and Hb, whilst standardbreds had the highest values of AA and LDH. Jumping horses had the highest Protox values. Females had significantly higher SOD values, whereas most of the other markers were higher in stallions and geldings. Horses age 2-6 years had higher AA, SOD and LDH values than horses age >6 years. Correlation analyses were positive and significant between vitamin E and GPx, VitE and ACL, Se and GPx, Cu and Pool and negative between Pool and vitamin E, Pool and ACL, Protox and GPx, Protox and vitamin E. CONCLUSIONS: Blood oxidant/ antioxidant status of horses is influenced by breed, gender and age. The correlation analyses suggest synergistic relations between GPx, vitamin E and Se and an antagonistic relation between Protox-GPx, Protox-vitamin E, and Pool-vitamin E. POTENTIAL RELEVANCE: The results of this investigation provide definition of the specific need for antioxidants and vitamins in competition horses. [less ▲]

Detailed reference viewed: 9 (3 ULg)