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 detailOn the relation between bond quality and impact-echo frequency spectrum
Piotrowski, Tomasz; Garbacz, Andrzej; Van der Wielen, Audrey ULg et al

in Proceedings of the 13th International Congress on Polymers in Concrete ICPIC 2010 (2010)

According to EN 1504-10 and ACI Concrete Repair Manual, bond strength and interface quality are the main features of repair system necessary to be assessed. Pull-off test is most commonly used for bond ... [more ▼]

According to EN 1504-10 and ACI Concrete Repair Manual, bond strength and interface quality are the main features of repair system necessary to be assessed. Pull-off test is most commonly used for bond strength evaluation but growing interest in nondestructive techniques (NDT) is recently noted. Impact-echo (IE) is treated as the most promising one for this purpose. The aim of this paper is to analyze an effect of bond quality on stress wave propagation in repair systems. A group of samples has been prepared in order to obtain repair systems of different bond quality. Prior to repair, quality of concrete substrates has been characterized according different techniques: compressive strength, superficial cohesion, surface roughness index and cracking quantification. Than a polymer-modified repair mortar has been applied. Af-ter hardening, IE signals have been recorded and pull-off bond strength determined. The rela-tionships between parameters characterizing surface quality, bond strength, IE frequency spec-trum and results of wavelet analysis of IE signal have been analyzed. [less ▲]

Detailed reference viewed: 82 (15 ULg)
See detailOn the Relation of Programs and Computations to Models of Temporal Logic [chap. 3]
Wolper, Pierre ULg

in Bolc, Leonard; Sza\las, Andrzej (Eds.) Time and Logic, a computational approach (1995)

Detailed reference viewed: 14 (1 ULg)
Peer Reviewed
See detailON THE RELATIONSHIP BETWEEN DIETARY PATTERNS AND CARDIOVASCULAR RISK FACTORS IN THE GREATER REGION POPULATION
Sauvageot, Nicolas ULg; Alkerwi, Alaa; Zannad, Faiez et al

Conference (2013, October 25)

Abstract Background: The prevalence of chronic pathologies such as cardio-vascular diseases is increasing, in part due to dietary habits. Some dietary patterns may influence health more than individual ... [more ▼]

Abstract Background: The prevalence of chronic pathologies such as cardio-vascular diseases is increasing, in part due to dietary habits. Some dietary patterns may influence health more than individual foods, nutrients or food groups. The objective of this research was to identify dietary patterns associated with common cardiovascular risk factors (CVRF) in a sample of adult individuals living in the Greater Region. Methods: Data were taken from the cross-sectional NESCAV (Nutrition, Environment and Cardiovascular Health) study, aiming to describe the cardiovascular health of the Greater Region’s population (1). Dietary intake was assessed using a 132-item food frequency questionnaire (FFQ), from which 44 food groups were formed. Food group consumptions were adjusted for energy intake using the residuals method of Willet and Stampfer (2). Participants under a special diet to manage their CVRF were excluded. Likewise, those who had a history of cardiovascular disease or with confirmed diabetes, hypertension, and/or dyslipidemia were also discarded as they may have changed their diet. Thus, a total of 1691 individuals were included in the study (865 from Luxembourg, 527 from Wallonia and 299 from Lorraine). We applied the reduced rank regression method to identify specific dietary patterns strongly associated with common CVRF (3). The CVRF-specific dietary patterns were constructed by choosing intake data as predictors and CVRF as outcomes. Nine CVRF (BMI, waist to hip ratio, total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, blood glucose, diastolic and systolic blood pressure) were used in the statistical analysis. Associations between dietary patterns and CVRF were adjusted according to gender, age, smoking status and level of physical activity. Results: Two main dietary patterns were identified. A pattern characterized by high intakes of alcohol, potatoes and high-fat food such as pastries, fried foods, offal, processed and smoked meat, margarine, but low intakes of cereals, soups, soft drink and olive oil, was significantly associated with an increase of all CVRF. On the other hand, a healthy pattern characterized by high consumption of brown bread, nuts, soups, vegetables, smoked and canned fish, olive oil and oil rich in omega 6 and 3, high-fat dairy products, butter and margarine, but a low consumption of fried foods, rice/pasta, meat, ready meal, soft drink and beer, was associated with a decrease of all CVRF except LDL. Conclusions: Our results suggest that dietary patterns of the Greater Region population are related to CVRF. Diet rich in alcohol and high-fat food is associated with a higher cardiovascular risk whereas a healthy diet is associated with a lower cardiovascular risk. These results emphasize the need for cross-border preventive nutritional strategies. [less ▲]

Detailed reference viewed: 22 (3 ULg)
Full Text
Peer Reviewed
See detailOn the relationships between Jeffreys modal and weighted likelihood estimation of ability under logistic IRT models
Magis, David ULg; Raîche, Gilles

in Psychometrika (2012), 77

This paper focuses on two estimators of ability with logistic item response theory models: the Bayesian modal (BM) estimator and the weighted likelihood (WL) estimator. For the BM estimator, Jeffreys’ ... [more ▼]

This paper focuses on two estimators of ability with logistic item response theory models: the Bayesian modal (BM) estimator and the weighted likelihood (WL) estimator. For the BM estimator, Jeffreys’ prior distribution is considered, and the corresponding estimator is referred to as the Jeffreys modal (JM) estimator. It is established that under the three-parameter logistic model, the JM estimator returns larger estimates than the WL estimator. Several implications of this result are outlined. [less ▲]

Detailed reference viewed: 32 (4 ULg)
Full Text
Peer Reviewed
See detailOn the Relevance of Sophisticated Structural Annotations for Disulfide Connectivity Pattern Prediction
Becker, Julien ULg; Maes, Francis; Wehenkel, Louis ULg

in PLoS ONE (2013), 8(2), 56621

Disulfide bridges strongly constrain the native structure of many proteins and predicting their formation is therefore a key sub-problem of protein structure and function inference. Most recently proposed ... [more ▼]

Disulfide bridges strongly constrain the native structure of many proteins and predicting their formation is therefore a key sub-problem of protein structure and function inference. Most recently proposed approaches for this prediction problem adopt the following pipeline: first they enrich the primary sequence with structural annotations, second they apply a binary classifier to each candidate pair of cysteines to predict disulfide bonding probabilities and finally, they use a maximum weight graph matching algorithm to derive the predicted disulfide connectivity pattern of a protein. In this paper, we adopt this three step pipeline and propose an extensive study of the relevance of various structural annotations and feature encodings. In particular, we consider five kinds of structural annotations, among which three are novel in the context of disulfide bridge prediction. So as to be usable by machine learning algorithms, these annotations must be encoded into features. For this purpose, we propose four different feature encodings based on local windows and on different kinds of histograms. The combination of structural annotations with these possible encodings leads to a large number of possible feature functions. In order to identify a minimal subset of relevant feature functions among those, we propose an efficient and interpretable feature function selection scheme, designed so as to avoid any form of overfitting. We apply this scheme on top of three supervised learning algorithms: k-nearest neighbors, support vector machines and extremely randomized trees. Our results indicate that the use of only the PSSM (position-specific scoring matrix) together with the CSP (cysteine separation profile) are sufficient to construct a high performance disulfide pattern predictor and that extremely randomized trees reach a disulfide pattern prediction accuracy of on the benchmark dataset SPX+, which corresponds to +3.2% improvement over the state of the art. A web-application is available at http://m24.giga.ulg.ac.be:81/x3CysBridge​s. [less ▲]

Detailed reference viewed: 43 (15 ULg)
Full Text
See detailOn the Reliability of Error Localization Indicators
Pascual, Rodrigo; Golinval, Jean-Claude ULg; Razeto, Mario

Conference given outside the academic context (1998)

Detailed reference viewed: 18 (2 ULg)
Full Text
Peer Reviewed
See detailOn the Representation of Infinite Temporal Data and Queries
Baudinet, Marianne; Níezette, Marc; Wolper, Pierre ULg

in Proc. of the 10th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems (1991, May)

Detailed reference viewed: 10 (1 ULg)
Full Text
Peer Reviewed
See detailOn the representation of real numbers using regular languages
Lecomte, Pierre ULg; Rigo, Michel ULg

in Theory of Computing Systems (2002), 35(1, JAN-FEB), 13-38

Using a lexicographically ordered regular language, we show how to represent an interval of R. We determine exactly the possible representations of any element in this interval and study the function ... [more ▼]

Using a lexicographically ordered regular language, we show how to represent an interval of R. We determine exactly the possible representations of any element in this interval and study the function which maps a representation onto its numerical value. We make explicit the relationship between the convergence of finite words to an infinite word and the convergence of the corresponding approximations to a real number. [less ▲]

Detailed reference viewed: 42 (10 ULg)
Full Text
Peer Reviewed
See detailOn the representational systems underlying prospection: Evidence from the event-cueing paradigm.
D'Argembeau, Arnaud ULg; Demblon, Julie ULg

in Cognition (2012), 125(2), 160-167

The ability to think about the future-prospection-is central to many aspects of human cognition and behavior, from planning and decision making, to self-control and the construction of a sense of identity ... [more ▼]

The ability to think about the future-prospection-is central to many aspects of human cognition and behavior, from planning and decision making, to self-control and the construction of a sense of identity. Yet, the exact nature of the representational systems underlying prospection is not fully understood. Recent findings point to the critical role of episodic memory in imagining specific future events, but it is unlikely that prospection depends solely on this system. Using an event-cueing paradigm in two studies, we here show that specific events that people imagine might happen in their personal future are commonly embedded in broader event sequences-termed event clusters-that link a set of envisioned events according to causal and thematic relations. These findings provide novel evidence that prospection relies on multiple representational systems, with general autobiographical knowledge structures providing a frame that organizes imagined events in overarching event sequences. The results further suggest that knowledge about personal goals plays an important role in structuring these event sequences, especially for the distant future. [less ▲]

Detailed reference viewed: 30 (10 ULg)
Full Text
Peer Reviewed
See detailOn the residual advection of passive constituents
Delhez, Eric ULg

in Journal of Marine Systems (1996), 8(3-4), 147-169

In this paper, the different approaches used to simulate the long-term advection of passive constituents on tidal shelves are discussed in the framework of large scale hydrodynamic modelling. The direct ... [more ▼]

In this paper, the different approaches used to simulate the long-term advection of passive constituents on tidal shelves are discussed in the framework of large scale hydrodynamic modelling. The direct approach in which the unsteady mesoscale (tides and storm surges) and macroscale (monthly or seasonal mean processes) currents are used is very demanding in computer resources (CPU and memory). On the other hand, the use of residual velocities gives a larger understanding of the long-term transport processes and simplifies numerical treatments. However, the definition of such appropriate velocities is still an open question. In the context of large scale models, Lagrangian residuals are not applicable. Eulerian residual transport velocities fail to represent long-term motions when tidal non-linearities are important. The first order Lagrangian residual velocity introduced by Feng et al. (1986a) and generalized here is shown to be a very good solution. The North-Western European Continental Shelf (NWECS) is used as an example to compare the numerical solutions obtained with the different approaches. [less ▲]

Detailed reference viewed: 32 (11 ULg)
Full Text
Peer Reviewed
See detailOn the road to inclusion and respect for diversity : challenges for a quality. An experience being led in the French Community of Belgium
Camus, Pascale ULg

Conference (2010, December 08)

The conference has been centred on an approach of conditions that make each and every child really feel welcome in ECEC services. Following the European childcare network activities in the nineties, the ... [more ▼]

The conference has been centred on an approach of conditions that make each and every child really feel welcome in ECEC services. Following the European childcare network activities in the nineties, the French Community Government (Belgium) has decided to issue the Quality and Care Code : every person who takes care of a child aged 0 to 12 has to elaborate and implement an educational project called in French “projet d’accueil”. This project has to follow the objectives defined by the Quality and Care Code. There is an essential challenge, on various levels of course, but more specifically in terms of development of ECEC services quality : services should be accessible to every child and his family. A short stop on what is meant by “quality of ECEC services” has been proposed. [less ▲]

Detailed reference viewed: 8 (0 ULg)
Full Text
See detailOn the Road to Killingworth: Boston B.A.E.F. Fellows Get-Together(s)
Reuchamps, Min ULg

in B.A.E.F. Belgian American Educational Foundation (Ed.) Liber Amicorum for 30th years of Prof. Boulpaep Presidency (2007)

Detailed reference viewed: 35 (6 ULg)
See detailOn the Robustness of Air-Sea Flux Estimates of Carbon Dioxide from Ocean Inversions
Mikaloff Fletcher, S. E.; Gruber, N. P.; Jacobson, A. et al

Conference (2004, December)

Inverse methods analogous to those used for atmospheric inversions have been adapted to estimate regional air-sea fluxes of carbon dioxide using ocean interior observations of dissolved inorganic carbon ... [more ▼]

Inverse methods analogous to those used for atmospheric inversions have been adapted to estimate regional air-sea fluxes of carbon dioxide using ocean interior observations of dissolved inorganic carbon and related tracers and an Ocean General Circulation Model (OGCM). We estimate seperately the preindustrial component and the component due to the anthropogenic perturbation of atmospheric carbon dioxide. Previous sensitivity studies have shown that model circulation is one of the most important sources of error in the ocean inversion. We present estimates of preindustrial and anthropogenic air-sea carbon dioxide exchange using a suite of nine different OGCM's in order to quantify the robustness of our results and explore the role of different representations of ocean circulation in the inversion. Most of the large scale features of the inverse estimates are robust across all models. The preindustrial inverse estimates generally follow the expected pattern of uptake at high latitudes and out gassing in the tropics; however, all of the models call for out gassing in the Southern Ocean between 44S and 58 S. The greatest anthropogenic carbon uptake occurs at mid- to high- latitudes, with a large anthropogenic carbon sink in the Southern Ocean, while the bulk of the anthropogenic carbon storage occurs at mid-latitudes. Preliminary results also suggest interesting, robust differences between these inverse estimates and estimates from forward model simulations. Both the preindustrial and anthropogenic carbon dioxide flux estimates are most robust at mid and high northern latitudes, except for the high latitude North Atlantic. The carbon dioxide flux estimates are most uncertain in the Southern Ocean, where the inverse estimates are strongly dependent on the rates of deep water ventilation in the OGCM. The preindustrial inverse estimates for the Indian Ocean are also sensitive to the choice of OGCM, and the anthropogenic estimates have significant uncertainties in the tropical Pacific. Over large spatial scales, inverse estimates based on different OGCM's are in better agreement than estimates based on forward simulations of the same models, but this is not necessarily true for smaller model regions. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
See detailOn the Role of Out-of-Equilibrium Microstructures in Ti-6Al-4V and in Stainless Steel 316L Processed by Selective Laser Melting in Determining their Mechanical Properties
Mertens, Anne ULg; Reginster, Sylvie ULg; Paydas, Hakan ULg et al

Conference (2013, September 12)

Additive manufacturing processes such as Selective Laser Melting (SLM) appear very promising in view of the economic production of near-net-shape, complex and (almost) fully dense parts from metallic ... [more ▼]

Additive manufacturing processes such as Selective Laser Melting (SLM) appear very promising in view of the economic production of near-net-shape, complex and (almost) fully dense parts from metallic materials such as Ti alloys and stainless steels. Practically, in SLM, a metallic powder is deposited layer-by-layer in a powder bed and then molten locally according to the desired shape. An important feature of this process is that the structure undergoes an ultra-fast cooling once the beam leaves the working zone, thus giving rise to strongly out-of-equilibrium microstructures. In the case of Ti alloy Ti-6Al-4V, in particular, the microstructural anisotropy resulting from the epitaxial growth of the newly deposited layer on the material previously solidified has been shown to exert a very strong influence on the mechanical properties [1]. In the present work, the microstructures and mechanical properties of Ti-6Al-4V and of stainless steel 316L processed by SLM have been characterised in details. Since these two materials exhibit quite different physical behaviours, their careful comparison might shed more light into the role of phenomena such as epitaxial growth, out-of-equilibrium phase transformation and/or internal stresses in determining the mechanical properties of metallic parts processed by SLM. [less ▲]

Detailed reference viewed: 88 (11 ULg)
Full Text
Peer Reviewed
See detailOn the role of pressure in elasto-inertial turbulence
Terrapon, Vincent ULg; Dubief, Yves; Soria, Julio

in Journal of Turbulence (2014), 16(1), 26-43

The dynamics of elasto-inertial turbulence is investigated numerically from the perspective of the coupling between polymer dynamics and flow structures. In particular, direct numerical simulations of ... [more ▼]

The dynamics of elasto-inertial turbulence is investigated numerically from the perspective of the coupling between polymer dynamics and flow structures. In particular, direct numerical simulations of channel flow with Reynolds numbers ranging from 1000 to 6000 are used to study the formation and dynamics of elastic instabilities and their effects on the flow. Based on the splitting of the pressure into inertial and polymeric contributions, it is shown that the polymeric pressure is a non-negligible component of the total pressure fluctuations, although the rapid inertial part dominates. Unlike Newtonian flows, the slow inertial part is almost negligible in elasto-inertial turbulence. Statistics on the different terms of the Reynolds stress transport equation also illustrate the energy transfers between polymers and turbulence and the redistributive role of pressure. Finally, the trains of cylindrical structures around sheets of high polymer extension that are characteristics of elasto-inertial turbulence are shown to be correlated with the polymeric pressure fluctuations. [less ▲]

Detailed reference viewed: 56 (13 ULg)
Full Text
Peer Reviewed
See detailOn the Role of the Deterministic and Circumferential Stresses in Throughflow Calculations
Simon, Jean-Francois; Léonard, Olivier ULg

in Proceedings of the ASME Turbo Expo 2008 (2008, June)

Detailed reference viewed: 18 (0 ULg)
Peer Reviewed
See detailOn the Role of the Deterministic and Circumferential Stresses in Throughflow Calculations
Simon, Jean-Francois; Thomas, Jean-Philippe ULg; Léonard, Olivier ULg

in Journal of Turbomachinery (2009), 131(3),

This paper presents a throughflow analysis tool developed in the context of the average-passage flow model elaborated by Adamczyk. The Adamczyk's flow model describes the 3D time-averaged flow field ... [more ▼]

This paper presents a throughflow analysis tool developed in the context of the average-passage flow model elaborated by Adamczyk. The Adamczyk's flow model describes the 3D time-averaged flow field within a blade row passage. The set of equations that governs this flow field is obtained by performing a Reynolds averaging, a time averaging, and a passage-to-passage averaging on the Navier–Stokes equations. The throughflow level of approximation is obtained by performing an additional circumferential averaging on the 3D average-passage flow. The resulting set of equations is similar to the 2D axisymmetric Navier–Stokes equations, but additional terms resulting from the averages show up: blade forces, blade blockage factor, Reynolds stresses, deterministic stresses, passage-to-passage stresses, and circumferential stresses. This set of equations represents the ultimate throughflow model provided that all stresses and blade forces can be modeled. The relative importance of these additional terms is studied in the present contribution. The stresses and the blade forces are determined from 3D steady and unsteady databases (a low-speed compressor stage and a transonic turbine stage) and incorporated in a throughflow model based on the axisymmetric Navier–Stokes equations. A good agreement between the throughflow solution and the averaged 3D results is obtained. These results are also compared to those obtained with a more “classical” throughflow approach based on a Navier–Stokes formulation for the endwall losses, correlations for profile losses, and a simple radial mixing model assuming turbulent diffusion. [less ▲]

Detailed reference viewed: 85 (28 ULg)