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See detailReading in a new technology environment: Are reading assessments still in the ballpark?
Reichert, Monique UL; Krämer, Charlotte UL; Wollschläger, Rachel UL

Scientific Conference (2019, May 31)

Using digital technologies for daily activities such as communicating or learning has become ubiquitous today. This trend is also clearly visible within the field of reading habits, especially among ... [more ▼]

Using digital technologies for daily activities such as communicating or learning has become ubiquitous today. This trend is also clearly visible within the field of reading habits, especially among adolescents: Recent studies underline that traditional text types (e.g., fiction books) are no longer part of the more commonly read text materials (Duncan et al., 2016). The question addressed in the presentation will deal with the degree to which different reading habits impact on adolescents’ reading competence, and is intended to encourage a discussion about the construct of reading competence as generally operationalized in reading competence assessments. We base our considerations on the analyses of two data sets: The first one deals with the extra-curricular reading habits of 3074 9th grade students, and the impact of these practices on their German reading competence. The corresponding data are taken from a survey regarding their reading habits in terms of ten different types of texts (e.g., non-fiction books, e-mails). A regression analysis reveals the strongest impact on reading competence for narrative texts, whilst reading digital texts – although highly attractive among the students – is found to be of minor importance. The second data set differentiates between the reading habits of around 4500 adolescents regarding 1) traditional (printed) texts, 2) digitalised texts (e.g., e-books), and 3) text types that have emerged with new technologies (e.g., social media texts). The ensuing discussion compares particularities of classical and digital texts, and raises questions concerning the construct of reading competence (to be) targeted by standardized tests. [less ▲]

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See detailMonitoring du système scolaire – Le modèle luxembourgeois (invited talk)
Fischbach, Antoine UL

Scientific Conference (2019, May 21)

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See detailWho’s afraid of Donkey Kong? Testing the Stereotype Threat Effect in Video Gaming
Holl, Elisabeth UL; Wagener, Gary L.; Melzer, André UL

Scientific Conference (2019, May)

In two studies (Study 1: N = 130; Study 2: N = 56) participants played a video game (Bejeweled 3; SkyChasers) and were either confronted with a stereotype threat (ST) or not. ST is defined as the risk of ... [more ▼]

In two studies (Study 1: N = 130; Study 2: N = 56) participants played a video game (Bejeweled 3; SkyChasers) and were either confronted with a stereotype threat (ST) or not. ST is defined as the risk of confirming a negative stereotype about one’s own group and has been investigated in various field, i.a. in gaming. In the first study participants were confronted with the stereotype that women would perform worse in video games than men. In the second study we worked with a reversed stereotype, namely that women would have now outpaced males in some genres of video games. Our results show that performance varies across gender and genre. Although we did not find the hypothesized interaction effect of gender and ST condition in performance, self-reported measures, such as perceived frustration, and moderating variables indicate performance differences both for women and men, but on different psychological dimensions. [less ▲]

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See detailComputational chemo-thermo-mechanical coupling phase-field model for complex fracture induced by early-age shrinkage and hydration heat in cement-based materials
Nguyen, Thanh Tung UL; Waldmann, Danièle UL; Bui, T. Q.

in Computer Methods in Applied Mechanics and Engineering (2019), 348

In this paper, we present a new multi-physics computational framework that enables us to capture and investigate complex fracture behavior in cement-based materials at early-age. The present model ... [more ▼]

In this paper, we present a new multi-physics computational framework that enables us to capture and investigate complex fracture behavior in cement-based materials at early-age. The present model consists of coupling the most important chemo-thermo-mechanical processes to describe temperature evolution, variation of hydration degree, and mechanical behavior. The changes of material properties are expressed as a function of the hydration degree, to capture the age effects. Fracture analysis of these processes are then accommodated by a versatile phase field model in the framework of smeared crack models, addressing the influence of cracks on hydration and thermal transfer. We additionally describe a stable and robust numerical algorithm, which aims to solve coupled problems by using a staggered scheme. The developed approach is applied to study the fracture phenomena at both macroscopic and mesoscopic scales, in which all microstructural heterogeneities of sand and cement matrix are explicitly accounted. Nucleation, initiation, and propagation of complex crack network are simulated in an efficient way demonstrating the potential of the proposed approach to assess the early-age defects in concrete structures and materials. [less ▲]

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See detailParallel coordinate descent algorithms for sparse phase retrieval
Yang, Yang UL; Pesavento, Marius; Eldar, Yonina C. et al

in Proc. 2019 IEEE International Conference on Acoustics, Speech and Signal (ICASSP) (2019, May)

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See detailVIEW-INVARIANT ACTION RECOGNITION FROM RGB DATA VIA 3D POSE ESTIMATION
Baptista, Renato UL; Ghorbel, Enjie UL; Papadopoulos, Konstantinos UL et al

in IEEE International Conference on Acoustics, Speech and Signal Processing, Brighton, UK, 12–17 May 2019 (2019, May)

In this paper, we propose a novel view-invariant action recognition method using a single monocular RGB camera. View-invariance remains a very challenging topic in 2D action recognition due to the lack of ... [more ▼]

In this paper, we propose a novel view-invariant action recognition method using a single monocular RGB camera. View-invariance remains a very challenging topic in 2D action recognition due to the lack of 3D information in RGB images. Most successful approaches make use of the concept of knowledge transfer by projecting 3D synthetic data to multiple viewpoints. Instead of relying on knowledge transfer, we propose to augment the RGB data by a third dimension by means of 3D skeleton estimation from 2D images using a CNN-based pose estimator. In order to ensure view-invariance, a pre-processing for alignment is applied followed by data expansion as a way for denoising. Finally, a Long-Short Term Memory (LSTM) architecture is used to model the temporal dependency between skeletons. The proposed network is trained to directly recognize actions from aligned 3D skeletons. The experiments performed on the challenging Northwestern-UCLA dataset show the superiority of our approach as compared to state-of-the-art ones. [less ▲]

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See detailLearning to Sport and Refactor Inconsistent Method Names
Liu, Kui UL; Kim, Dongsun; Bissyande, Tegawendé François D Assise UL et al

in 41st ACM/IEEE International Conference on Software Engineering (ICSE) (2019, May)

To ensure code readability and facilitate software maintenance, program methods must be named properly. In particular, method names must be consistent with the corresponding method implementations ... [more ▼]

To ensure code readability and facilitate software maintenance, program methods must be named properly. In particular, method names must be consistent with the corresponding method implementations. Debugging method names remains an important topic in the literature, where various approaches analyze commonalities among method names in a large dataset to detect inconsistent method names and suggest better ones. We note that the state-of-the-art does not analyze the implemented code itself to assess consistency. We thus propose a novel automated approach to debugging method names based on the analysis of consistency between method names and method code. The approach leverages deep feature representation techniques adapted to the nature of each artifact. Experimental results on over 2.1 million Java methods show that we can achieve up to 15 percentage points improvement over the state-of-the-art, establishing a record performance of 67.9% F1-measure in identifying inconsistent method names. We further demonstrate that our approach yields up to 25% accuracy in suggesting full names, while the state-of-the-art lags far behind at 1.1% accuracy. Finally, we report on our success in fixing 66 inconsistent method names in a live study on projects in the wild. [less ▲]

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See detailBrauchen wir noch Kontinuitätenbiografien? Der Fall Franz Thedieck (1900-1995)
Brüll, Christoph UL

Presentation (2019, April 29)

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See detailYou Cannot Fix What You Cannot Find! An Investigation of Fault Localization Bias in Benchmarking Automated Program Repair Systems
Liu, Kui UL; Koyuncu, Anil UL; Bissyande, Tegawendé François D Assise UL et al

in The 12th IEEE International Conference on Software Testing, Verification and Validation (ICST-2019) (2019, April 24)

Properly benchmarking Automated Program Repair (APR) systems should contribute to the development and adoption of the research outputs by practitioners. To that end, the research community must ensure ... [more ▼]

Properly benchmarking Automated Program Repair (APR) systems should contribute to the development and adoption of the research outputs by practitioners. To that end, the research community must ensure that it reaches significant milestones by reliably comparing state-of-the-art tools for a better understanding of their strengths and weaknesses. In this work, we identify and investigate a practical bias caused by the fault localization (FL) step in a repair pipeline. We propose to highlight the different fault localization configurations used in the literature, and their impact on APR systems when applied to the Defects4J benchmark. Then, we explore the performance variations that can be achieved by "tweaking'' the FL step. Eventually, we expect to create a new momentum for (1) full disclosure of APR experimental procedures with respect to FL, (2) realistic expectations of repairing bugs in Defects4J, as well as (3) reliable performance comparison among the state-of-the-art APR systems, and against the baseline performance results of our thoroughly assessed kPAR repair tool. Our main findings include: (a) only a subset of Defects4J bugs can be currently localized by commonly-used FL techniques; (b) current practice of comparing state-of-the-art APR systems (i.e., counting the number of fixed bugs) is potentially misleading due to the bias of FL configurations; and (c) APR authors do not properly qualify their performance achievement with respect to the different tuning parameters implemented in APR systems. [less ▲]

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See detailIoT Device Fingerprinting: Machine Learning based Encrypted Traffic Analysis
Msadek, Mohamed Nizar UL; Soua, Ridha UL; Engel, Thomas UL

in The IEEE Wireless Communications and Networking Conference (WCNC) (2019, April 19)

Even in the face of strong encryption, the spectacular Internet of Things (IoT) penetration across sectors such as e-health, energy, transportation, and entertainment is expanding the attack surface ... [more ▼]

Even in the face of strong encryption, the spectacular Internet of Things (IoT) penetration across sectors such as e-health, energy, transportation, and entertainment is expanding the attack surface, which can seriously harm users’ privacy. We demonstrate in this paper that an attacker is able to disclose sensitive information about the IoT device, such as its type,by identifying specific patterns in IoT traffic. To perform the fingerprint attack, we train machine-learning algorithms based on selected features extracted from the encrypted IoT traffic.Extensive simulations involving the baseline approach show that we achieve not only a significant mean accuracy improvement of 18.5% and but also a speedup of 18.39 times for finding the best estimators. Obtained results should spur the attention of policymakers and IoT vendors to secure the IoT devices they bring to market. [less ▲]

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See detailSocial Media as an Opportunity for Public Health Interventions: The #Metoo Movement as an Exemplar
Gomez Bravo, Raquel UL; Gomez Bravo, María; Lygidakis, Charilaos UL et al

in Journal of the International Society for Telemedicine and EHealth (2019), 7(e5), 1-7

Background: Social media have been used exponentially and globally, providing a means for billions of users to connect, interact, share opinions and criticise, becoming one of the main channels of ... [more ▼]

Background: Social media have been used exponentially and globally, providing a means for billions of users to connect, interact, share opinions and criticise, becoming one of the main channels of communication for users around the world. One of the most popular free social media networks is Twitter, with more than 100 million active users per day worldwide. Purpose: The aim of this study was to analyse a sample of the public conversations generated, using the hashtag #MeToo, around the topic of sexual abuse on Twitter. Methods: Using social media marketing software, the use of the #MeToo hashtag was analysed over a period of 60 days (14 September 2017 to 13 November of 2017). Results: The #MeToo conversation was mainly in English (79.3%), located in the United States (48.2% of cases), but with global repercussions. The volume of mentions of the #MeToo hashtag was far greater (97.7%), compared with other hashtags related to violence over this period of time, using mostly Twitter (96.2%). Conclusions: These results suggest that it is possible to describe different groups using the social media, and analyse their conversations to identify opportunities for successful public health interventions. If the topic is relevant for the general public, it will generate interest and conversations at the global level, supported by a universal and borderless channel such as Twitter. [less ▲]

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See detailLe Web des années 1990: entre données et reconstructions
Schafer, Valerie UL

Presentation (2019, April 14)

Cette présentation revient sur les travaux menées autour de l'histoire du Web des années 1990 et présente les enjeux de lecture proche et distante des archives du Web au sein de cette recherche.

Detailed reference viewed: 37 (0 UL)
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See detailHow can we support lecturers in English-medium instruction?
Deroey, Katrien UL

Scientific Conference (2019, April 13)

English-medium instruction (EMI) is a worldwide phenomenon. EMI language and communication issues (e.g. Hu et al., 2014; Murray, 2015; Werther et al., 2014) have led to calls for EAP practitioners to ... [more ▼]

English-medium instruction (EMI) is a worldwide phenomenon. EMI language and communication issues (e.g. Hu et al., 2014; Murray, 2015; Werther et al., 2014) have led to calls for EAP practitioners to collaborate with lecturers and other HE stakeholders to explore ways in which these lecturers can be supported and teaching standards ensured (Coleman, 2006; Doiz et al., 2013; Dubow & Gundermann, 2017). The design and implementation of EMI training and support programmes can be an especially challenging task for EAP practitioners. First, lecturers may not recognize the need for support and may be reluctant to be assessed. Second, we need to factor in practical considerations such as their limited availability and possible reluctance to attend ‘classes’ with colleagues. Third, we have limited resources in terms of specialized standardized tests, training materials and research literature that could inform our 'course' design. Innovative approaches are therefore needed to factor in all these circumstances. This paper has two main parts. First I summarize research on the challenges EMI lecturers face, including the results of a needs analysis among lecturers at the University of Luxembourg and my work on lecture discourse organization (Deroey, 2015). From the relatively few studies that exist, we will see that lecturers tend to believe they have sufficient English language skills and that reduced interactivity is a particularly common issue. Second, I survey different support and training schemes at HE institutions across the world. Here, it will become clear that work on relevant pedagogical skills needs to be included and an apparently ‘remedial’ approach should be avoided if we want to get lecturers on board. [less ▲]

Detailed reference viewed: 42 (0 UL)
See detailTranslanguaging in a Multilingual Classroom in Luxembourg
Degano, Sarah UL

Presentation (2019, April 12)

Research in bilingual and trilingual schools shows that knowledge and understanding can be increased by translanguaging (Baker & Wright 2017, Kirsch 2017), the enactment of a student’s linguistic and non ... [more ▼]

Research in bilingual and trilingual schools shows that knowledge and understanding can be increased by translanguaging (Baker & Wright 2017, Kirsch 2017), the enactment of a student’s linguistic and non-linguistic resources. Yet, research on translanguaging including migrant languages in multilingual schools remains scarce (Duarte 2018). In multilingual Luxembourg, over 60% of the students indicate to have a dominant home language other than Luxembourgish, with Portuguese being the most used language (MENJE 2018). Considering that theteaching of Luxembourgish, French and German accounts for 40.5% of the instruction time, little room is left for the students’ home languages and the school system is particularly challenging for the students whose language repertoires deviate from the official curriculum. The present doctoral project investigates how primary school students with a migration background deploy their language repertoires to learn. In this paper, I examine the extent to which two fourth-graders with a Portuguese background and a different migration experience mobilize their languages while interacting with the teacher and peers. Data stem from eighteen days of observation and video-recordings. The thematic analysis focuses on the students’ participation and their language use in different school subjects. Preliminary findings show that the students participate unequally and use their languages differently in terms of purpose and frequency and depending on their migration experience. The findings are tentative because data collection is on-going. [less ▲]

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See detailADVANCES IN GEOMETRY INDEPENDENT APPROXIMATIONS
Anitescu, Cosmin; Atroshchenko, Elena; Bordas, Stéphane UL et al

Scientific Conference (2019, April 11)

We present recent advances in geometry independent field approximations. The GIFT approach is a generalisation of isogeometric analysis where the approximation used to describe the field variables no ... [more ▼]

We present recent advances in geometry independent field approximations. The GIFT approach is a generalisation of isogeometric analysis where the approximation used to describe the field variables no-longer has to be identical to the approximation used to describe the geometry of the domain. As such, the geometry can be described using usual CAD representations, e.g. NURBS, which are the most common in the CAD area, whilst local refinement and meshes approximations can be used to describe the field variables, enabling local adaptivity. We show in which cases the approach passes the patch test and present applications to various mechanics, fracture and multi-physics problems. [less ▲]

Detailed reference viewed: 117 (1 UL)
See detailLes résistances belge et luxembourgeoise et leurs conceptions européennes
Brüll, Christoph UL

Scientific Conference (2019, April 10)

La deuxième Occupation allemande en un quart de siècle a vu se développer en Belgique et au Luxembourg une série de mouvements de Résistance aux caractéristiques et conceptions politiques très diverses ... [more ▼]

La deuxième Occupation allemande en un quart de siècle a vu se développer en Belgique et au Luxembourg une série de mouvements de Résistance aux caractéristiques et conceptions politiques très diverses. Parmi les Résistants qui s’interrogent sur l’après-guerre, deux tendances lourdes s’affirment : le rétablissement de l’indépendance nationale et la démilitarisation d’une Allemagne vaincue. Il en résulte aussi des plans pour l’Europe qui reposent toutefois rarement sur une approche systématique de la question. Une importance cruciale revient à la question des liens entre mouvements de Résistance et gouvernements en exil. Par ailleurs, il y a des personnalités qui, comme le futur Premier ministre luxembourgeois Pierre Werner, s’engagent aux côtés de la Résistance française et réfléchissent sur l’avenir du continent. La contribution se propose d’établir un inventaire de ces initiatives et d’adopter (là où c’est possible) une perspective comparatiste. Finalement, nous examinerons le rôle des mouvements de Résistance dans la vie politique de l’après-guerre et l’engagement de certains Résistants dans les débuts de l’intégration européenne après 1945. [less ▲]

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See detailBORDERS IN THE LIVES OF ASYLUM SEEKERS & REFUGEES IN LUXEMBOURG & METZ
Paraschivescu, Claudia UL

E-print/Working paper (2019)

Detailed reference viewed: 38 (1 UL)
See detailIntegrated micromechanical model for slope stability analysis
Kabore, Brice Wendlassida UL; Peters, Bernhard UL

Scientific Conference (2019, April 09)

Advances in supercomputing hardware have made it possible to handle highly complex geomechanical analysis with large data. Thus, particle-based methods are gaining an ever-increasing interest with ... [more ▼]

Advances in supercomputing hardware have made it possible to handle highly complex geomechanical analysis with large data. Thus, particle-based methods are gaining an ever-increasing interest with massively parallel programs being developed. These methods have been applied to the analysis of failure mechanisms and scenarios such as mass movement in landslides, avalanches under static, dynamic or seismic loading condition. They provide deep insights into the meso and micro-scale mechanisms leading to macroscopic instabilities. This contribution describes a micromechanical model for stability analysis and simulation in natural or man-made slopes under complex loading and boundary conditions. Based on the micromechanics of loose granular and compacted geomaterial, microstructural change, viscoelastic deformations, fracture, and healing are explicitly integrated into a coupled discrete particle and beam lattice model. Stress-based failure criteria and energy based dissipation and frictional contact are employed. Both gravity increase and strength reduction methods have been employed to evaluate the Factor of Safety (FoS) and potential failure surface and compared. With an emphasis on the impact of the microstructure and its spatial variability on stress-induced microcracks and crack propagation, this study outlines material models and properties relevant to stability analysis. Special focus has been put on layered slopes which present varying shear strength along the depth formed over time according to pressure, temperature, and moisture such as snowpack. This microstructural approach unifies geometrical and material information and allows the structural assembling layers of different strength. [less ▲]

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See detailAn interface resolved immersed boundary method in XDEM for particulate flow simulations
Wu, Mingqiu UL; Peters, Bernhard UL; Rosemann, Tony et al

in International Congress on Particle Technology (2019, April 09)

immersed boundary method (IBM) has recently been used for particulate flows and complex fluid-solid interaction problems. The IBM was first introduced by Peskin to simulate blood flow in a beating heart ... [more ▼]

immersed boundary method (IBM) has recently been used for particulate flows and complex fluid-solid interaction problems. The IBM was first introduced by Peskin to simulate blood flow in a beating heart. Later it has been extended for a different range of applications. The advantages of IBM over the body-fitted method is that it substantially simplified grid generation for immersed geometries, and it is easier to handle moving boundary situations. IBM even allows the use of a stationary and non-deformation background mesh, as well as it reduces the cost of computation by avoiding generation of a body-fitted mesh for each time step. However, the IBM approach is not straightforward to implement and it requires special techniques for cut-off boundary cells as well as special techniques for data point interpolations. Generally, the IBM is classified into two approaches based on the methods of imposing the boundary condition in the immersed body. The first approach is called fictitious domain method with continuous forcing scheme which employs a distributed forcing function to impose a rigidity boundary condition in the solid particle domain. The second one is the discrete forcing approach, which enables a sharp interface to represent the immersed surface. The IBM discussed in this work is a combination of these above two approaches: we first employ the continuous forcing scheme to get a first-step approximation of the immersed body, then use an interpolation polynomial to impose a desired accurate physical boundary for each immersed boundary point based on a least square interpolation reconstruction scheme. Particle motions can be calculated and tracked by solving Newton’s equations of motions using the extended discrete element method (XDEM) while the data of fluid flow properties are obtained by solving the Navier-Stokes equations which govern the fluid phase. Combined this leads to the basic concept of DEM-CFD coupling. Therefore, a particle interface resolved simulation solver is developed by coupling the XDEM and IBM approaches together. Consequently, this solver is then used to handle both static and dynamic particle problems as well as particle packed bed simulations. The validation of the solver can be performed by setting one static sphere in a channel and evaluate the drag coefficients and Strouhal number (when shedding occurs) at various Reynolds [less ▲]

Detailed reference viewed: 49 (8 UL)