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See detailNonlinear generalization of Den Hartog's equal peak method for nonlinear primary systems
Habib, Giuseppe ULg; Detroux, Thibaut ULg; Kerschen, Gaëtan ULg

in Proceedings of the International Conference on Structural Nonlinear Dynamics and Diagnosis (2014)

This study addresses the mitigation of one problem nonlinear resonance of a mechanical system. In view of the narrow bandwidth of the classical linear tuned vibration absorber, a new nonlinear absorber ... [more ▼]

This study addresses the mitigation of one problem nonlinear resonance of a mechanical system. In view of the narrow bandwidth of the classical linear tuned vibration absorber, a new nonlinear absorber, termed the nonlinear tuned vibration absorber (NLTVA), is introduced in this paper. One unconventional aspect of the NLTVA is that the mathematical form of its restoring force is tailored according to the nonlinear restoring force of the primary system. The NLTVA parameters are then determined using a nonlinear generalization of Den Hartog's equal-peak method. The mitigation of the resonant vibrations of a Duffing oscillator is considered to illustrate the proposed developments. [less ▲]

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See detailLotze et son héritage. Son influence et son impact sur la philosophie du XXème siècle
Boccaccini, Federico ULg

Book published by Peter Lang (2014)

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See detailStefano Poggi, James lecteur de Lotze
Boccaccini, Federico ULg

in Boccaccini, Federico (Ed.) Lotze et son héritage. Son influence et son impact sur la philosophie du XXème siècle (2014)

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See detailD'un point de vue intentionnel. Aspects et enjeux de la philosophie de Roderick Chisholm
Boccaccini, Federico ULg

in Bulletin d'Analyse Phénoménologique (2014)

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See detailProcedural learning across modalities in French-speaking children with specific language impairment
Gabriel, Audrey ULg; Meulemans, Thierry ULg; Parisse, Christophe et al

in Applied Psycholinguistics (2014)

It has been suggested that the language problems encountered in specific language impairment (SLI) arise from basal ganglia abnormalities that lead to impaired procedural memory. However, recent serial ... [more ▼]

It has been suggested that the language problems encountered in specific language impairment (SLI) arise from basal ganglia abnormalities that lead to impaired procedural memory. However, recent serial reaction time (SRT) studies did not reveal any differences between the SLI and typically developing (TD) groups on the measures of procedural memory linked to visual sequence learning. In this paper, 16 children with and without SLI were compared on two versions of SRT tasks: a visual task and an auditory one. The results showed that children with SLI were as fast as their TD peers in both modalities. All of the children obtained similar specific sequence learning indices, indicating that they were able to detect regularities in both modalities. Although children with SLI were as accurate as their TD peers for the visual SRT task, they made more errors than their TD peers in auditory SRT conditions. The results indicate that, in relation to procedural memory, the core of the impairment in SLI is not linked to difficulties in the detection of regularities. We argue that when children with SLI present some difficulties, the children’s weaknesses might depend on the type of processing involved (e.g., tasks involving auditory sequences). [less ▲]

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See detailAutomated Defect Detection Algorithm Applied to Shearography in Composites
Vandenrijt, Jean-François ULg; Georges, Marc ULg

in Osten, Wolfgang (Ed.) Fringe 2013 (2014)

The aeronautic industry is progressively introducing composite material in its products. Nowadays the fabrication begins to be mature, but huge efforts remains to be done on the experimental validation of ... [more ▼]

The aeronautic industry is progressively introducing composite material in its products. Nowadays the fabrication begins to be mature, but huge efforts remains to be done on the experimental validation of these materials. More specifically, these composite materials introduce new type of defects (such as delamination, glue defects…) which need to be detected during the fabrication and maintenance to prevent failures. Moreover, the widespread use of these materials impose to the future detection instruments to be cheap, robust and easy to manipulate by non-specialists. Currently shearography is widely used for the detection of defects in the composite material. It is cheap, and relatively robust and flexible, but requires special qualification to interpret the shearograms and identify the defects. Therefore, efforts need to be carried to ease the interpretation of stereographic results for non-specialist of the technique. For this, we propose to automate the identification of defects in shearograms by the development of specific algorithms. In this paper, we present an innovative algorithm which realizes this operation. The process inspects the wrapped phase map obtained to identify high local fringe density. These potential detects are then analyzed and selected based on a set of parameter criteria such as dimensions, shape, and detection threshold. Successful results obtained on thermally solicited composite sample observed in industrial conditions are shown. We also discuss the limitations and perspective of this approach. [less ▲]

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See detailSimultaneous Temperature and Deformations Measurements Using Long-Wave Infrared Speckle Interferometry: A Novel Hybrid Technique for Industrial Nondestructive Testing
Georges, Marc ULg; Vandenrijt, Jean-François ULg; Thizy, Cédric ULg et al

in Osten, Wolfgang (Ed.) Fringe 2013 (2014)

The use of long-wave infrared (LWIR) CO2 lasers and microbolometer arrays in digital holographic and speckle interferometry shows interesting features for full-field displacement/deformation metrology and ... [more ▼]

The use of long-wave infrared (LWIR) CO2 lasers and microbolometer arrays in digital holographic and speckle interferometry shows interesting features for full-field displacement/deformation metrology and nondestructive testing. The first one is that the long wavelength yields the measurement of larger displacements together with decreasing the sensitivity to environmental perturbations. Therefore these interferometric methods can be applied more easily in industrial field applications. Another advantage was put forward in the European project FANTOM which is presented in this paper. In addition to specklegrams, the thermal background is captured simultaneously. Therefore in displacement metrology one can correlate uniquely the temperature and displacement information at the same time and in each pixel. We describe the successful achievements of the project. Thorough understanding of optics and speckle interferometry crossed with state-of-art in thermam imaging systems allowed to study this new hybrid technique in deep and tackle some specific constraints for reaching the best performances. As a result, a mobile instrument has been developed and validated on various industrial structural testing facilities and inspection areas. It has been used in thermomechanical measurements as well as in detection of defects in aeronautical composites. In particular we show that the two parts of the signal (the thermal part on one hand and the interferograms showing the deformation on the other hand) yield complementary information. A very interesting result is that it allows increasing the probability of detecting defects, for some of them are better seen in the thermal signal, whereas others appear only through local surface deformation. [less ▲]

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See detailLe Théâtre Flamand. Le progrès en scène.
Prina, Daniela ULg

Conference (2014)

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See detailDigital Holographic Interferometry in the Long-Wave Infrared for the Testing of Large Aspheric Space Reflectors
Vandenrijt, Jean-François ULg; Thizy, Cédric ULg; Stockman, Yvan ULg et al

in Osten, Wolfgang (Ed.) Fringe 2013 (2014)

Digital holographic (DH) interferometry has been developed in the long-wave infrared spectral range with CO2 lasers and microbolometer arrays. This application has been driven by the European Space ... [more ▼]

Digital holographic (DH) interferometry has been developed in the long-wave infrared spectral range with CO2 lasers and microbolometer arrays. This application has been driven by the European Space Agency’s constant need of techniques for monitoring large displacements of large structures. Here the study focuses on the case of aspheric mirrors, like parabola and ellipses. Usually they are tested through interferometric wavefront error measurements which require expensive null-lenses matching each of the reflectors considered. In the case of monitoring deformation a holographic technique can be considered where the wavefront is compared with itself at different instant. Therefore the optical can be quite simple and easily reconfigurable from one reflector to another. The advantage of using long wavelength is that large deformations can be measured at once, in addition to being more immune against environmental perturbations. Another advantage of DH at such wavelengths is that the ratio between the wavelength and the pixel size allows reconstructing objects 5 to 10 times larger than with DH in the visible. In this project we considered first the case of a 1.1 meter diameter parabola for submillimeter range observations. Such specimen shows strong specular reflectivity. We have developed several set-ups with different ways to illuminate the object and to collect rays to form the object beam: either through point source or through and extended diffuser working by reflection of the laser beam. Both possibilities have been compared in terms of fringe quality as well as measurement range. We selected the diffuser illumination for applying the set-up into a large vacuum facility for measuring the deformation of the parabola between 224 and 107 K. Results of this measurement campaign are presented. A further application has been shown by observation of off-axis ellipse. In this case interferometric testing is difficult to achieve and LWIR DHI with diffuser illumination is found quite simple to implement and gives straightforward results. [less ▲]

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See detailSartre in Venedig: der Mann, der in die Kälte ging
Cormann, Grégory ULg; Viehöver, Vera ULg

in Carnets Jean-Paul Sartre - 20. Geburtstag der Sartre Gesellschaft (2014)

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See detailSubspace-based identification of a nonlinear spacecraft in the time and frequency domains
Noël, Jean-Philippe ULg; Marchesiello, Stefano; Kerschen, Gaëtan ULg

in Mechanical Systems & Signal Processing (2014), 43(1-2), 217-236

The objective of the present paper is to address the identification of a strongly nonlinear satellite structure. To this end, two nonlinear subspace identification methods formulated in the time and ... [more ▼]

The objective of the present paper is to address the identification of a strongly nonlinear satellite structure. To this end, two nonlinear subspace identification methods formulated in the time and frequency domains are exploited, referred to as the TNSI and FNSI methods, respectively. The modal parameters of the underlying linear structure and the coefficients of the nonlinearities will be estimated by these two approaches based on periodic random measurements. Their respective merits will also be discussed in terms of both accuracy and computational efficiency and the use of stabilisation diagrams in nonlinear system identification will be introduced. The application of interest is the SmallSat spacecraft developed by EADS-Astrium, which possesses an impact-type nonlinear device consisting of eight mechanical stops limiting the motion of an inertia wheel mounted on an elastomeric interface. This application is challenging for several reasons including the non-smooth nature of the nonlinearities, high modal density and high non-proportional damping. [less ▲]

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See detailDorsomedial prefrontal metabolism and unawareness of current characteristics of personality traits in Alzheimer’s disease
Jedidi, Haroun ULg; Feyers, Dorothée ULg; Collette, Fabienne ULg et al

in Social Cognitive and Affective Neuroscience (2014)

Anosognosia is a complex symptom corresponding to a lack of awareness of one’s current clinical status. Anosognosia for cognitive deficits has frequently been described in Alzheimer’s disease (AD), while ... [more ▼]

Anosognosia is a complex symptom corresponding to a lack of awareness of one’s current clinical status. Anosognosia for cognitive deficits has frequently been described in Alzheimer’s disease (AD), while unawareness of current characteristics of personality traits has rarely been considered. We used a well-established questionnaire-based method in a group of 37 AD patients and in healthy controls to probe self- and hetero-evaluation of patients’ personality and we calculated differential scores between each participant’s and his/her relative’s judgments. A brain-behavior correlation was performed using FDG-PET images. The behavioral data showed that AD patients presented with anosognosia for current characteristics of their personality and their anosognosia was primarily explained by impaired third perspective taking. The brain-behavior correlation analysis revealed a negative relationship between anosognosia for current characteristics of personality and dorsomedial prefrontal cortex (dMPFC) activity. Behavioral and neuroimaging data are consistent with the view that impairment of different functions subserved by the dMPFC (self-evaluation, inferences regarding complex enduring dispositions of self and others, confrontation of perspectives in interpersonal scripts) plays a role in anosognosia for current characteristics of personality in AD patients. [less ▲]

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See detailMapping Diasporic Subjectivities
Munos, Delphine ULg; Pandurang, Mala

in South Asian Diaspora (2014), 6(1),

The last two decades have witnessed a growing interest in theorizing literary narratives that address the South Asian diasporic experience. By and large, however, what has emerged is an academic consensus ... [more ▼]

The last two decades have witnessed a growing interest in theorizing literary narratives that address the South Asian diasporic experience. By and large, however, what has emerged is an academic consensus which accords an ever-greater visibility to mainstream diasporic voices from North America, U.K., some parts of Africa and of the Caribbean, at the expense of narratives dealing with South Asian diasporic communities that are based in other locations. Also, such critical consensus valorizes certain class-streamed patterns of migration over others, with the result of homogenizing the diversity of today’s South Asian diaspora. This special issue explores literary representations of the migrant experiences of those underrepresented South Asian communities based in locations such as South America, East Europe, the Gulf, West Africa and East Asia. [less ▲]

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See detailEvent-triggered transmission for linear control over communication channels
Forni, Fulvio ULg; Galeani, Sergio; Nesic, Dragan et al

in Automatica (2014), 50(2), 490498

We consider an exponentially stable closed loop interconnection of a continuous linear plant and a continuous linear controller, and we study the problem of interconnecting the plant output to the ... [more ▼]

We consider an exponentially stable closed loop interconnection of a continuous linear plant and a continuous linear controller, and we study the problem of interconnecting the plant output to the controller input through a digital channel. We propose a family of "transmission-lazy" sensors whose goal is to transmit the measured plant output information as little as possible while preserving closed-loop stability. In particular, we propose two transmission policies, providing conditions on the transmission parameters. These guarantee global asymptotic stability when the plant state is available or when an estimate of the state is available (provided by a classical continuous linear observer). Moreover, under a specific condition, they guarantee global exponential stability [less ▲]

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See detailCervical cancer and HPV: Awareness and vaccine acceptability among parents in Morocco.
Mouallif, Mustapha; Bowyer, Harriet L.; Festali, Soukaina et al

in Vaccine (2014), 32(3), 409-16

Cervical cancer is a major public health concern in Morocco where it represents the second most common and lethal cancer in women. Human papillomavirus (HPV) vaccines have been licensed in Morocco since ... [more ▼]

Cervical cancer is a major public health concern in Morocco where it represents the second most common and lethal cancer in women. Human papillomavirus (HPV) vaccines have been licensed in Morocco since 2008 but there are no available data on their acceptability. This study aimed to assess awareness of HPV and the vaccine, and to identify factors associated with acceptability of the vaccine among parents in Morocco. We carried out a questionnaire-based survey using face-to-face interviews in a sample of 852 parents (670 mothers and 182 fathers) with at least one unmarried daughter </=26 years. We collected data within public and private health centres and clinics in four regions in Morocco between July and August 2012. The main outcome measure was parental acceptability of the HPV vaccine for their daughter(s). Responses revealed very low awareness of HPV infection (4.7%) and the HPV vaccine (14.3%). None of the participants had vaccinated their daughter(s) against HPV and vaccine acceptability was low among mothers (32%) and fathers (45%). Higher education and income, previous awareness of the HPV vaccine and endorsement of the belief that a recommendation from the Ministry of Health or a doctor to have the vaccine would be encouraging, were associated with mothers' HPV vaccine acceptability. Non-acceptability among mothers was associated with having more than two daughters, believing the vaccine was expensive, lack of information and believing that whatever happens to an individual's health is God's will. The only factor associated with the fathers' acceptability of the vaccine was the cost of the vaccine. Increasing HPV and HPV vaccine awareness through educational campaigns, along with active recommendation by physicians and a publically funded vaccination programme could increase parental acceptability of the HPV vaccine in Morocco. [less ▲]

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See detailIntroduction to Mapping Diasporic Subjectivities
Munos, Delphine ULg; Pandurang, Mala

in South Asian Diaspora (2014), 6(1), 1-5

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See detailHybride Modellierung deichbruchinduzierter Strömungen
Roger, Sebastian; Dewals, Benjamin ULg; Schüttrumpf, Holger

in Heimerl, S.; Meyer, H. (Eds.) Vorsorgender und nachsorgender Hochwasserschutz (2014)

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