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
Peer Reviewed
See detailQu'il est long le chemin vers l'équité...
Lafontaine, Dominique ULg

in L'école, dans quel(s) sens ? Actes du 2e Congrès des chercheurs en éducation, Louvain-la-Neuve, 12-13 mars 2002 (2003)

Detailed reference viewed: 13 (1 ULg)
See detailQu'y a-t-il autour de Neptune?
Manfroid, Jean ULg; Haefner, R.; Bouchet, P.

Article for general public (1986)

Not Available

Detailed reference viewed: 8 (1 ULg)
Full Text
Peer Reviewed
See detailA Quadrangular Shell Finite Element for Concrete and Steel Structures Subjected to Fire
Talamona, Didier; Franssen, Jean-Marc ULg

in Journal of Fire Protection Engineering (2005), 15

Detailed reference viewed: 30 (1 ULg)
Full Text
Peer Reviewed
See detailA Quadratic Programming Framework for Constrained and Robust Jet Engine Health Monitiring
Borguet, Sébastien ULg; Léonard, Olivier ULg

in Proceedings of the 2nd European Conference on Aerospace Sciences (2007)

Kalman filters are largely used in the jet engine community for condition monitoring purpose. This algorithm gives a good estimate of the engine condition provided that the residuals between the model ... [more ▼]

Kalman filters are largely used in the jet engine community for condition monitoring purpose. This algorithm gives a good estimate of the engine condition provided that the residuals between the model prediction and the measurements are zero-mean, Gaussian random variables. In the case of sensor faults, this assumption does not hold anymore and consequently the diagnosis is spoiled. This contribution presents a recursive estimation algorithm based on a Quadratic Programming formulation which provides robustness against sensor faults and allows constraints on the health parameters to be specified. The improvements in estimation accuracy brought by this new algorithm are illustrated by a series of typical test-cases that may be encountered on current turbofan engines. [less ▲]

Detailed reference viewed: 10 (2 ULg)
See detailA Quadratic Programming Framework for Constrained and Robust Jet Engine
Borguet, Sébastien ULg; Léonard, Olivier ULg

in EUCASS Advances in Aerospace Sciences : Propulsion Physics (2009)

Kalman filters are largely used in the jet engine community for condition monitoring purpose. This algorithm gives a good estimate of the engine condition provided that the residuals between the model ... [more ▼]

Kalman filters are largely used in the jet engine community for condition monitoring purpose. This algorithm gives a good estimate of the engine condition provided that the residuals between the model prediction and the measurements are zero-mean, Gaussian random variables. In the case of sensor faults, this assumption does not hold anymore and consequently the diagnosis is spoiled. This contribution presents a recursive estimation algorithm based on a Quadratic Programming formulation which provides robustness against sensor faults and allows constraints on the health parameters to be specified. The improvements in estimation accuracy brought by this new algorithm are illustrated by a series of typical test-cases that may be encountered on current turbofan engines. [less ▲]

Detailed reference viewed: 25 (8 ULg)
See detailQuadratic reformulations of nonlinear binary optimization problems
Crama, Yves ULg

Conference (2014, January 30)

Detailed reference viewed: 20 (0 ULg)
See detailQuadratic reformulations of nonlinear binary optimization problems
Crama, Yves ULg

Conference (2014, January 06)

Detailed reference viewed: 14 (1 ULg)
See detailQuadratic reformulations of nonlinear binary optimization problems
Crama, Yves ULg

Conference (2013, July 01)

We consider the problem of minimizing a pseudo-Boolean function f(x), i.e., a real-valued function of 0-1 variables. Several authors have recently proposed to reduce this problem to the quadratic case by ... [more ▼]

We consider the problem of minimizing a pseudo-Boolean function f(x), i.e., a real-valued function of 0-1 variables. Several authors have recently proposed to reduce this problem to the quadratic case by expressing f(x) as min{g(x,y): y in {0,1}}, where g is a quadratic function of x and of additional binary variables y. We establish lower and upper bounds on the number of additional y-variables needed in such a reformulation, both for the general case and for the special case of symmetricfunctions like positive or negative monomials, k-out-of-n majority functions, or parity functions. [less ▲]

Detailed reference viewed: 35 (1 ULg)
See detailQuadratization of pseudo-Boolean functions
Crama, Yves ULg

Scientific conference (2013, June 20)

Detailed reference viewed: 7 (0 ULg)
Full Text
See detailQuadratization of symmetric pseudo-Boolean functions
Anthony, Martin; Boros, Endre; Crama, Yves ULg et al

E-print/Working paper (2013)

A pseudo-Boolean function is a real-valued function $f(x)=f(x_1,x_2,\ldots,x_n)$ of $n$ binary variables; that is, a mapping from $\{0,1\}^n$ to ${\bbr}$. For a pseudo-Boolean function $f(x)$ on $\{0,1 ... [more ▼]

A pseudo-Boolean function is a real-valued function $f(x)=f(x_1,x_2,\ldots,x_n)$ of $n$ binary variables; that is, a mapping from $\{0,1\}^n$ to ${\bbr}$. For a pseudo-Boolean function $f(x)$ on $\{0,1\}^n$, we say that $g(x,y)$ is a quadratization of $f$ if $g(x,y)$ is a quadratic polynomial depending on $x$ and on $m$ auxiliary binary variables $y_1,y_2,\ldots,y_m$ such that $f(x)= \min \{ g(x,y) : y \in \{0,1\}^m \} $ for all $x \in \{0,1\}^n$. By means of quadratizations, minimization of $f$ is reduced to minimization (over its extended set of variables) of the quadratic function $g(x,y)$. This is of some practical interest because minimization of quadratic functions has been thoroughly studied for the last few decades, and much progress has been made in solving such problems exactly or heuristically. A related paper initiated a systematic study of the minimum number of auxiliary $y$-variables required in a quadratization of an arbitrary function $f$ (a natural question, since the complexity of minimizing the quadratic function $g(x,y)$ depends, among other factors, on the number of binary variables). In this paper, we determine more precisely the number of auxiliary variables required by quadratizations of \emph{symmetric} pseudo-Boolean functions $f(x)$, those functions whose value depends only on the Hamming weight of the input $x$ (the number of variables equal to 1). [less ▲]

Detailed reference viewed: 50 (3 ULg)
Full Text
See detailQuadratization of symmetric pseudo-Boolean functions
Crama, Yves ULg

Conference (2013, April)

We consider the problem of minimizing an arbitrary pseudo-Boolean function f(x), that is, a real-valued function of 0-1 variables. In recent years, several authors have proposed to reduce this problem to ... [more ▼]

We consider the problem of minimizing an arbitrary pseudo-Boolean function f(x), that is, a real-valued function of 0-1 variables. In recent years, several authors have proposed to reduce this problem to the quadratic case by expressing f(x) as min{g(x,y):y∈{0,1}^m}, where g(x,y) is a quadratic pseudo-Boolean function of x and of additional binary variables y. We say that g(x,y) is a quadratization of f. In this talk, we investigate the number of additional variables needed in a quadratization when f is a symmetric function of the x-variables. The cases where f is either a positive or a negative monomial are of particular interest, but some of our techniques also extend to more complex functions, like k-out-of-n or parity functions. Joint work with Martin Anthony, Endre Boros and Aritanan Gruber [less ▲]

Detailed reference viewed: 21 (0 ULg)
Full Text
Peer Reviewed
See detailQuadriceps and Hamstring Isokinetic Strength and Electromyographic Activity Measured at Different Ranges of Motion: A Reproducibility Study
Croisier, Jean-Louis ULg; Malnati, Michael; Reichard, Leon B et al

in Journal of Electromyography & Kinesiology (2007), 17(4), 484-92

Isokinetic strength measurements of the quadriceps and hamstring that are commonly conducted using a 90 degrees range of motion (RoM) may involve some risk to specific knee patient groups. Testing these ... [more ▼]

Isokinetic strength measurements of the quadriceps and hamstring that are commonly conducted using a 90 degrees range of motion (RoM) may involve some risk to specific knee patient groups. Testing these muscles at a much shorter RoM may reduce the risk but in order to render this method clinically acceptable the reproducibility of the derived test findings has to be established. Therefore the main objective of this study was to assess the reproducibility of isokinetic peak torque and normalized EMG scores of these muscles based on 90 degrees (0-90 degrees flexion, LR) and three successive short RoMs: 0-30 degrees (SR1), 30-60 degrees (SR2) and 60-90 degrees (SR3). Eight healthy subjects were tested three times with a 2 week between-session interval. All tests were performed on the dominant limb and consisted of maximal concentric and eccentric exertions. The velocities applied were 90 degrees /s for LR and 30 degrees /s for each of the SRs. Findings indicated no between-session improvement in strength. Based on the coefficient of variation the measurement error for all isokinetic strength scores remained stable throughout the testing sessions ranging 0.6-13.9% with the absolute majority of instances less than 10%. The reproducibility of the EMG scores was poorer ranging 1.5-25% and 0.5-19% for the quadriceps and hamstring, respectively. It is concluded that testing of knee muscles at short (30 degrees ) RoMs does not compromise the reproducibility of the strength or EMG scores derived from the commonly used RoM of 90 degrees . However, whereas strength was reproducible to within the accepted clinical standards, the corresponding EMG scores were characterized by a wider error band. [less ▲]

Detailed reference viewed: 73 (3 ULg)
Full Text
Peer Reviewed
See detailQuadripulse Repetitive Transcranial Magnetic Stimulation on Visual Cortex for Chronic Migraine Prevention: A Pilot-Trial
Sasso d'Elia, Tullia; Vigano, Alessandro; Fataki, Michel et al

in Cephalalgia : An International Journal of Headache (2013), 33(8), 49

Detailed reference viewed: 12 (1 ULg)
Full Text
See detailQuadro legal da mediaçao vitima-agressor na Europa continental
Lauwaert, Katrien ULg

in Newsletter DGAE (2003), (2), 12-18

Detailed reference viewed: 10 (0 ULg)
Full Text
Peer Reviewed
See detailThe Quadruple Wolf-Rayet System GP Cephei: Spectral Types, Masses, Mass-Loss Rate, and Colliding Winds
Demers, H.; Moffat, A. F. J.; Marchenko, S. V. et al

in Astrophysical Journal (2002), 577

We have reevaluated the orbital elements for each pair of the quadruple (W-R+O) + (O+O) stellar system GP Cep and propose new spectral types WN6o/WCE + O3-6, B0: I + B1: V-III. It is shown that there is ... [more ▼]

We have reevaluated the orbital elements for each pair of the quadruple (W-R+O) + (O+O) stellar system GP Cep and propose new spectral types WN6o/WCE + O3-6, B0: I + B1: V-III. It is shown that there is only one Wolf-Rayet (W-R) star in GP Cep, contrary to a previous claim. A rate of change P=1.3+/-0.2 s yr[SUP]-1[/SUP] is determined for the W-R+O pair, which leads to a new period of 6.6887 days and to a W-R mass-loss rate of (0.8-3.0)à 10[SUP]-5[/SUP] M[SUB]solar[/SUB] yr[SUP]-1[/SUP]. Masses for this pair are estimated to be M[SUB]W-R[/SUB]>~6 M[SUB]solar[/SUB] and M[SUB]O[/SUB]>~21 M[SUB]solar[/SUB]. The effects of wind-wind collision in the W-R+O pair are studied. It is shown that even after allowing for dilution by the OB components of the quadruple system, these effects are not as strong as in the binary V444 Cygni (WN5+O6, P=4.212 days). In GP Cep, the phase-dependent, relatively weak excess emission does not originate in the arms of the bow shock cone. Rather, it emerges from the extra heated portion of the W-R wind facing the hot O companion. The trailing bow shock arm is clearly seen, however, as an enhanced He I absorption component near quadrature at phase ~0.73. An anomalous blueshifted He I absorption is present at phase ~0.9, as is also seen in V444 Cyg, in the WC8+O9 I/O8 III binary γ Velorum and in the LBV-cotype binary R81 (B2.5 Iab:e). A 3.5 day orbit for the eclipsing B star pair is confirmed. [less ▲]

Detailed reference viewed: 20 (1 ULg)
Full Text
Peer Reviewed
See detailA quadruply imaged quasar with an optical Einstein ring candidate: 1RXS J113155.4-123155
Sluse, D.; Surdej, Jean ULg; Claeskens, Jean-François ULg et al

in Astronomy and Astrophysics (2003), 406(Letters), 43-46

We report the discovery of a new quadruply imaged quasar surrounded by an optical Einstein ring candidate. Spectra of the different components of 1RXS J113155.4-123155 reveal a source at z= 0.658. Up to ... [more ▼]

We report the discovery of a new quadruply imaged quasar surrounded by an optical Einstein ring candidate. Spectra of the different components of 1RXS J113155.4-123155 reveal a source at z= 0.658. Up to now, this object is the closest known gravitationally lensed quasar. The lensing galaxy is clearly detected. Its redshift is measured to be z= 0.295. Additionally, the total V magnitude of the system has varied by 0.3 mag between two epochs separated by 33 weeks. The measured relative astrometry of the lensed images is best fitted with an SIS model plus shear. This modeling suggests very high magnification of the source (up to 50 for the total magnification) and predicts flux ratios between the lensed images significantly different from what is actually observed. This suggests that the lensed images may be affected by a combination of micro or milli-lensing and dust extinction effects. Based on data collected at the European Southern Observatory, La Silla, Chile. [less ▲]

Detailed reference viewed: 17 (6 ULg)
Full Text
See detailQual Pedagogia para os alunos em dificuldade escolar ?
Crahay, Marcel ULg

in Cadernos de Pesquisas (2007), 37(130), 181-208

Detailed reference viewed: 167 (0 ULg)
See detailQuale futuro per l’italiano in Belgio
Lucchini, Silvia ULg

Conference given outside the academic context (2007)

Detailed reference viewed: 6 (0 ULg)
See detailQuale futuro per la psicoterapia psicoanalitica
Gauthier, Jean-Marie ULg

in Frisch, S.; Hinshelwood, R.-D. (Eds.) Psychoanalysis and psychotherapy (2001)

Detailed reference viewed: 12 (0 ULg)