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
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)
Full Text
Peer Reviewed
See detailQualification d’un appareil d'éclairage décoratif soumis aux vibrations induites par un pont ferroviaire
Marin, Frédéric; Simon, Daniel; Golinval, Jean-Claude ULg

in Serra, Roger (Ed.) 3ième Colloque "Analyse Vibratoire Expérimentale" (2012, November)

Au même titre que la plupart des pièces mécaniques soumises aux vibrations, les appareils d'éclairage installés en extérieur sont amenés à satisfaire, en fonction de leurs conditions d’utilisation, aux ... [more ▼]

Au même titre que la plupart des pièces mécaniques soumises aux vibrations, les appareils d'éclairage installés en extérieur sont amenés à satisfaire, en fonction de leurs conditions d’utilisation, aux exigences de procédures d'essais appliquées sur table vibrante. Celles-ci ont pour but de garantir l'intégrité structurelle du luminaire lorsque, une fois sur site, il est soumis aux effets du vent. Dans le cas des appareils d'éclairage décoratifs installés sur un pont de chemin de fer de structure métallique, le vent n'étant plus la source principale de vibrations en comparaison du trafic ferroviaire, on est dès lors confronté à une absence de toute indication appropriée décrivant l'essai à mener. Par conséquent, l'objectif de cette étude est d'élaborer une spécification d'essai de durée réduite, appliquée en laboratoire sur table vibrante, et représentative de l'environnement vibratoire réel de l'appareil à certifier. Sur base des essais réalisés en laboratoire, des prescriptions de montage et d'installation sont également formulées afin de garantir des conditions d’utilisation et d’essai identiques. [less ▲]

Detailed reference viewed: 33 (4 ULg)
Full Text
See detailQualification de grands réflecteurs en environnement spatial
Thizy, Cédric ULg; Stockman, Yvan ULg; Doyle, Dominic et al

in Smigielski, P. (Ed.) Actes du Cinquième colloque francophone Méthodes et Techniques Optiques pour l'Industrie (2004, November)

Les nouvelles générations de télescopes spatiaux dans le domaine infrarouge nécessitent des réflecteurs de grandes dimensions et de haute qualité. Ceux-ci, pour des raisons de poids, sont basés sur les ... [more ▼]

Les nouvelles générations de télescopes spatiaux dans le domaine infrarouge nécessitent des réflecteurs de grandes dimensions et de haute qualité. Ceux-ci, pour des raisons de poids, sont basés sur les technologies des matériaux composites dont les comportements aux basses températures sont mal connus. Une méthode par interférométrie holographique de vérification et de validation en environnement spatial de ce type de réflecteurs est présentée. Elle est basée sur l'utilisation d'une caméra holographique dynamique observant un dépoli sur lequel est projeté le faisceau objet venant de la surface réfléchissante. Outre une augmentation de la dynamique de mesure, cette méthode offre l’avantage principal, par rapport aux techniques d’interférométrie optique, de ne pas nécessiter de système optique d’adaptation du front d’onde au réflecteur à mesurer et donc un gain de flexibilité majeur pour des formes exotiques de réflecteurs (types asphériques). Le système de mesure a été calibré avec un interféromètre ponctuel à effet Doppler. L'influence des différentes sources d’erreur du système sur la mesure a été évaluée. Cette évaluation a porté principalement sur des aspects vibratoires et thermiques. Ces réflecteurs devant être testés sous vide et à basses températures, le système de mesure a été rendu compatible à ces conditions. Des éléments de la caméra holographique (objectifs, CCD, cristal, fibre optique) ont été adaptés et testés sous vide. La certification métrologique de l’ensemble du système sera réalisée par la mesure d'une antenne parabolique, de 1.1 m de diamètre de comportement connu et placée dans un environnement spatial simulé. Le test consistera à mesurer les déplacements et déformations de l'antenne entre un état initial à la température ambiante, et un état final à une température d'environ 130K. [less ▲]

Detailed reference viewed: 37 (6 ULg)
Full Text
See detailQualification de l'appareillage
Mbinze Kindenge, Jérémie; Marini Djang'Eing'A, Roland ULg; Lecomte, Frédéric ULg et al

Learning material (2008)

Fournir des bases et une information générale sur le principe de la qualification d'un équipement analytique.

Detailed reference viewed: 285 (56 ULg)
Full Text
Peer Reviewed
See detailLa qualification imprécise face au droit à l'information du prévenu
Michiels, Olivier ULg

in Revue de Droit Pénal et de Criminologie (2009), 2

La qualification d’un fait au regard de la loi pénale est l’une des opérations les plus courantes mais aussi des plus délicates de la mission du juge. A cet effet, il importe que l’ordonnance de renvoi ou ... [more ▼]

La qualification d’un fait au regard de la loi pénale est l’une des opérations les plus courantes mais aussi des plus délicates de la mission du juge. A cet effet, il importe que l’ordonnance de renvoi ou la citation du ministère public ou de la partie civile indique de manière précise le fait susceptible d’être incriminé. Il se pourrait cependant qu’en pratique le juge se trouve confronté à la difficulté d’identifier le fait dont il est saisi. C'est précisément cette hypothèse que l'article rencontre. [less ▲]

Detailed reference viewed: 174 (9 ULg)
See detailLa qualification juridique de la relation de travail
Clesse, Jacques ULg

in Questions de droit social (2007)

Detailed reference viewed: 33 (12 ULg)
Peer Reviewed
See detailQualification of an experimentation centre to test visibility conditions in fog.
Colomb, M.; Serezat, L.; Legoueix, G. et al

Conference (1999, August)

Detailed reference viewed: 4 (2 ULg)
Full Text
Peer Reviewed
See detailQualification of BSO crystals for use onboard the International Space Station
Georges, Marc ULg; Dupont, Olivier ULg; Zayer, I. et al

in Delaye, Ph; Denz, C.; Mager, L. (Eds.) Photorefractive Effects, Materials, and Devices (2003, June)

BSO crystals are excellent recording media for use in the holographic instrument of a multiple diagnostic instrument (Fluid Science Laboratory), for monitoring fluid phenomena onboard the ISS. Some ... [more ▼]

BSO crystals are excellent recording media for use in the holographic instrument of a multiple diagnostic instrument (Fluid Science Laboratory), for monitoring fluid phenomena onboard the ISS. Some experiments have been already presented that showed the potentiality of BSO for this kind of application. Here we present the crystals qualification for use within FSL with respect to gamma rays and protons radiations [less ▲]

Detailed reference viewed: 3757 (3 ULg)
Full Text
Peer Reviewed
See detailQualification of large reflectors in space environment with a holographic camera based on a BSO crystal
Thizy, Cédric ULg; Stockman, Yvan ULg; Lemaire, Philippe ULg et al

in Zhang, G.; Kip, D.; Nolte, D. (Eds.) et al Photorefractive Effects, Materials, and Devices (2005, July)

The next generation of infrared - sub mm space telescopes requires some reflectors with large dimensions and high quality. These ones, according to weight issues, are based on composite materials for ... [more ▼]

The next generation of infrared - sub mm space telescopes requires some reflectors with large dimensions and high quality. These ones, according to weight issues, are based on composite materials for which the behaviors at low temperatures are badly known. A holographic interferometry method for the verification and validation of this type of reflectors in a space environment is presented. It is based on a dynamic holographic camera observing a diffuser illuminated by the object beam coming from the reflecting surface. Photorefractive crystals being self-processing and reusable mediums, the measuring range of the holographic camera is increased with respect to other optical interferometric methods. The metrological certification of the whole system was realised by the measurement of a parabolic antenna with a 1.1 meter diameter, a known behavior and placed in a simulated space environment [less ▲]

Detailed reference viewed: 26 (2 ULg)
Full Text
See detailQualification Procedure of Luminaires in the Event of an Impact to the Pole
Marin, Frédéric; Marville, Christian; Golinval, Jean-Claude ULg

Conference given outside the academic context (2009)

The objective of the study is to develop a testing specification on an electrodynamic shaker which ensures the qualification of a parking lighting device, whose pole is impacted by a car. The methodology ... [more ▼]

The objective of the study is to develop a testing specification on an electrodynamic shaker which ensures the qualification of a parking lighting device, whose pole is impacted by a car. The methodology is based on both a numerical approach and an experimental approach using an electrodynamic shaker. The first step of the analysis consists in modeling the structure and the excitation by means of a finite element approach. The calculation of the dynamic response of the "pole/lighting device" system to impact loading is repeated for different geometries of the pole. The second step is to consider each dynamic response at the fixing point of the lighting device on the pole as input for a base-excited single degree of freedom system. The theory developed for such a system allows to define severity criteria like the Shock Response Spectrum (SRS) which is the most representative criterion in the case of an impact. The severity of the vibration environment of the lighting device is then obtained by considering the envelope of the different computed SRS. Finally, different test specifications leading to equivalent SRS are proposed and the device is tested on an electrodynamic shaker. The developed methodology was applied to the NEMO lighting device (Schréder). [less ▲]

Detailed reference viewed: 58 (8 ULg)