References of "Poster"
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See detailHow to threaten male gamers: The effects of stereotype threat on video game performance
Wagener, Gary L.; Melzer, André UL

Poster (2018, May)

A total of 70 participants (47.1% men) took part in a lab experiment that manipulated stereotype threat (i.e., the risk of confirming a negative stereotype about one’s group) between playing a video game ... [more ▼]

A total of 70 participants (47.1% men) took part in a lab experiment that manipulated stereotype threat (i.e., the risk of confirming a negative stereotype about one’s group) between playing a video game (Bejeweled 3). Participants performed generally worse after reading a fictitious article on gaming research that women would still play less and perform worse in games than men (ST condition). In contrast to males, however, female participants reported greater frustration from reading this article than their colleagues who read that women and men no longer differ in terms of playing frequency and performance skills (no ST condition). Interestingly, a reverse pattern of results was obtained for male participants, who reported a stronger negative effect of the article in the no ST condition on their ability to show their best gaming performance. Apparently, stereotype threat may affect video game performance both for women and men, but for different reasons. [less ▲]

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See detailTowards multiscale data fusion of high-resolution space borne and terrestrial datasets over Tristan da Cunha
Backes, Dietmar UL; Teferle, Felix Norman UL; Abraha, Kibrom Ebuy UL et al

Poster (2018, April 10)

Ever improving low cost, lightweight and easy to use sensing technologies are enabling the capture of rich 3D Datasets to support an unprecedented range of applications in Geosciences. Especially low-cost ... [more ▼]

Ever improving low cost, lightweight and easy to use sensing technologies are enabling the capture of rich 3D Datasets to support an unprecedented range of applications in Geosciences. Especially low-cost LiDAR systems as well as optical sensors, which can be deployed from terrestrial or low altitude aerial platforms, allow the collection of large datasets without detailed expert knowledge or training. Dense pointcloud derived from these technologies provide an invaluable source to fill the gap between highly precise and accurate terrestrial topographic surveys and large area Digital Surface Models (DSMs) derived from airborne and spaceborne sensors. However, the collection of reliable 3D pointclouds in remote and hazardous locations remains to be very difficult and costly. Establishing a reliable georeference, ensuring accuracy and data quality as well as merging such rich datasets with existing or space borne mapping provide additional challenges. The presented case study investigates the data quality and integration of a heterogeneous dataset collected over the remote island of Tristan da Cunha. High-resolution 3D pointclouds derived by TLS and drone Photogrammetry are merged with space borne imagery while preserving the accurate georeference provided by Ground Control derived from geodetic observations. The volcanic island of Tristan da Cunha located in the centre of the Southern Atlantic Ocean is one of the most remote and difficult to access locations on the planet. Its remote location, rough climatic conditions and consistent cloud coverage provides exceptional challenges for terrestrial, aerial as well as space borne data acquisition. Amongst many other scientific installations, the island also hosts a continuous GNSS station observation and monitoring facilities operated by the University of Luxembourg, which provided the opportunity to conduct a local terrestrial data acquisition campaign consistent with a terrestrial ground survey, Laserscanning and an image acquisition from a low-cost drone. The highly accurate Ground Control network, observed by GNSS and total station, provides a reliable georeference. Pointclouds were acquired around the area of the harbour using a Leica P20 terrestrial Laserscanner, as well as drone Photogrammetry based on images collected by a low-cost DJI Phantom3 drone. To produce a map of the complete island a comprehensive dataset of high-resolution space borne imagery based on the Digital Globe WorldView constellation was acquired which provided high resolution mapping information. The case study presents a cross-validation of terrestrial, low altitude airborne as well as spaceborne datasets in terms coregistration, absolute georeference, scale, resolution and overall data quality. Following the evaluation a practical approach to fuse this heterogeneous dataset is applied which aims to preserve overall data quality, local resolution and accurate georeference and avoid edge artefacts. The conclusions drawn from our preliminary results provide some good practice advice for similar projects. The final topographic dataset enables mapping and monitoring of local geohazards as, e.g. coastal erosion and recent landslides thus also supporting the local population. [less ▲]

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See detailVertical Land Movements and Sea Level Changes around South Georgia Island
Teferle, Felix Norman UL; Hunegnaw, Addisu UL; Abraha, Kibrom Ebuy UL et al

Poster (2018, April 09)

South Georgia Island in the Southern Atlantic Ocean is a key location for the seismic, geomagnetic and oceanic global monitoring networks. In its sub-Antarctic location, the island is largely covered by ... [more ▼]

South Georgia Island in the Southern Atlantic Ocean is a key location for the seismic, geomagnetic and oceanic global monitoring networks. In its sub-Antarctic location, the island is largely covered by mountain glaciers which have been reported to be retreating due to climatic change. Furthermore, during past glaciation periods the island and its shelf area have been ice covered as was revealed by scarring of the sub-oceanic topography. Together with ongoing tectonics along the North Scotia Ridge, these processes have the ability to produce significant uplift on local to regional scales, affecting the measurements of the tide gauge (GLOSS ID 187) at King Edward Point (KEP). Furthermore, with its mid-ocean location, the tide gauge is of particular interest to satellite altimetry calibrations over the Southern Atlantic and Southern Oceans. With the establishment of five GNSS stations on the islands during 2013 to 2015 and the scientific analysis of these data within the global network of stations of the International GNSS Service Tide Gauge Benchmark Monitoring (TIGA) working group, it has now become possible to study present-day vertical land movements of the region and their impacts on, for example, regional sea level. Furthermore, together with four precise levelling campaigns of the KEP benchmark network in 2013, 2014 and two in 2017, it has also been possible to investigate the very local character of the vertical motions near KEP, ie. the stability of the jetty upon which the tide gauge is mounted. In this study, we will present the still preliminary results from the GNSS and levelling measurements and will discuss their impact on the sea level record from the KEP tide gauge. Our measurements show that while South Georgia Island and the area around KEP are rising, the jetty and tide gauge are subsiding, leading to a disagreement in the observed sea level change from the tide gauge and satellite altimetry. In order to improve the agreement between these sea level measurements both local and regional vertical land movements need to be monitored. [less ▲]

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Peer Reviewed
See detailOvercoming language barriers in early mathematics instruction with “MaGrid” - a language-neutral training tool for multilingual school settings
Cornu, Véronique UL; Pazouki, Tahereh UL; Schiltz, Christine UL et al

Poster (2018, April 08)

Mathematical knowledge at the onset of formal schooling paves the way for children’s achievement in formal mathematics (e.g. Duncan et al., 2007; Watts et al., 2014). Hence, it is crucial to equip ... [more ▼]

Mathematical knowledge at the onset of formal schooling paves the way for children’s achievement in formal mathematics (e.g. Duncan et al., 2007; Watts et al., 2014). Hence, it is crucial to equip children with sound basic mathematical competencies by deploying effective teaching interventions during preschool years. However, multilingual school settings, such as Luxembourg (65% of the pupils are second language learners) pose a special challenge for instruction. Non-native pre-schoolers perform lower on early mathematics tests than their age-matched peers (Bonifacci et al., 2016; Kleemans et al., 2011). This gap is most likely due to missing out on learning opportunities, as a result of lower proficiency in the language of instruction. To provide equal access to early mathematics education for all children, we developed a language-neutral early mathematics training tool, the “MaGrid”-app. This innovative training tool has been evaluated, so far, in two studies in multilingual Luxembourg. In a first study, children from five classrooms (N = 68) used the tool to train visuo-spatial abilities, an important predictor of mathematical abilities (see e.g. Mix et al., 2016), over ten weeks (2x20min/week). At post-test, significant gains in the visuo-spatial domain were observed, compared to children from “teaching-as-usual” classrooms (N = 57). In a second study, we elaborated a comprehensive language-neutral early mathematics intervention, with “MaGrid” at its core. Findings from both training studies will be presented in detail and the importance of domain-specific versus domain-general precursors, as well as practical implications, will be discussed. [less ▲]

Detailed reference viewed: 39 (4 UL)
Peer Reviewed
See detailFourth-graders' competence beliefs in mathematics
Villanyi, Denise UL; Wollschläger, Rachel UL; Martin, Romain UL et al

Poster (2018, February 15)

Detailed reference viewed: 43 (10 UL)
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See detailUsing higher-order adjoints to accelerate the solution of UQ problems with random fields
Hale, Jack UL; Hauseux, Paul UL; Bordas, Stéphane UL

Poster (2018, January 08)

A powerful Monte Carlo variance reduction technique introduced in Cao and Zhang 2004 uses local derivatives to accelerate Monte Carlo estimation. This work aims to: develop a new derivative-driven ... [more ▼]

A powerful Monte Carlo variance reduction technique introduced in Cao and Zhang 2004 uses local derivatives to accelerate Monte Carlo estimation. This work aims to: develop a new derivative-driven estimator that works for SPDEs with uncertain data modelled as Gaussian random fields with Matérn covariance functions (infinite/high-dimensional problems) (Lindgren, Rue, and Lindström, 2011), use second-order derivative (Hessian) information for improved variance reduction over our approach in (Hauseux, Hale, and Bordas, 2017), demonstrate a software framework using FEniCS (Logg and Wells, 2010), dolfin-adjoint (Farrell et al., 2013) and PETSc (Balay et al., 2016) for automatic acceleration of MC estimation for a wide variety of PDEs on HPC architectures. [less ▲]

Detailed reference viewed: 83 (6 UL)
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See detailFirst Vertical Land Movement Estimates on South Georgia Island: An Impact Study on Sea Level Change from Tide Gauge and Altimetry Measurements
Teferle, Felix Norman UL; Hunegnaw, Addisu UL; Abraha, Kibrom Ebuy UL et al

Poster (2017, December 11)

South Georgia Island in the Southern Atlantic Ocean has been a key location for the seismic, geomagnetic and oceanic global monitoring networks. However, no permanent geodetic monitoring station had been ... [more ▼]

South Georgia Island in the Southern Atlantic Ocean has been a key location for the seismic, geomagnetic and oceanic global monitoring networks. However, no permanent geodetic monitoring station had been established there despite the lack of observations from this region within, for example, the International GNSS Service (IGS) network of Global Navigation Satellite System (GNSS) stations. Then, in 2013 the King Edward Point (KEP) Geodetic Observatory was established with a focus on sea level studies and in support of general geoscience applications. Currently, this observatory located roughly half-way along the main island and along its northern coastline, consists of two GNSS stations (KEPA and KRSA) with local benchmark networks, allowing the height determinations from the GNSS antennas to be transferred to the KEP tide gauge (GLOSS ID 187) and forming a height reference within the International Terrestrial Reference Frame. In late 2014, three additional GNSS stations (SG01, SG02 and SG03) were established, all on small islands at the perimeter of the main island. Together the stations provide the best possible opportunity to study various geophysical processes in the region. With the GNSS-derived position time series partly reaching over 4.5 years in length, it has become possible to provide first estimates of vertical land movements for the island and KEP with its surrounding area. Together with four precise levelling campaigns of the benchmark network in 2013, 2014 and two in 2017, it has also been possible to investigate the very local character of the vertical motions, ie. the stability of the jetty upon which the tide gauge is mounted. Our measurements show that while South Georgia Island and the area around KEP are rising, the jetty and tide gauge are subsiding. In this study, we will present the preliminary results from the GNSS and levelling measurements and will discuss their impact on the sea level record from the KEP tide gauge which is ideally situated in a mid-ocean location for satellite altimetry calibration over the Southern Atlantic and Southern Oceans. [less ▲]

Detailed reference viewed: 71 (10 UL)
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Peer Reviewed
See detailPoster: Characterizing Driving Behaviors Through a Car Simulation Platform
Faye, Sébastien UL; Jafarnejad, Sasan UL; Costamagna, Juan UL et al

Poster (2017, November 27)

Human mobility has opened up to many themes in recent years. Human behavior and how a driver might react to certain situations, whether dangerous (e.g. an accident) or simply part of the evolution of new ... [more ▼]

Human mobility has opened up to many themes in recent years. Human behavior and how a driver might react to certain situations, whether dangerous (e.g. an accident) or simply part of the evolution of new technologies (e.g. autonomous driving), leaves many avenues to be explored. Although experiments have been deployed in real situations, it remains difficult to encounter the conditions that certain studies may require. For this reason, we have set up a driving simulator (comprising several modules) that is able to reproduce a realistic driving environment. Although, as the literature has already demonstrated, the conditions are often far from reality, simulation platforms are nonetheless capable of reproducing an incredibly large number of scenarios on the fly. In this poster, we explain how we conceived the simulator, as well as the system we developed for collecting metrics on both the driver and the simulation environment. In addition, we take advantage of this conference to publicly share a dataset consisting of 25 drivers performing the same road circuit on the "Project Cars" game. [less ▲]

Detailed reference viewed: 81 (14 UL)
See detailEarly life stress reduces neuropathic pain in adulthood -is alteration of spinal microglial reactivity critically involved?
Genty, Julien UL; Tetsi Nomigni, Milène UL; Anton, Fernand UL et al

Poster (2017, November 14)

Growing evidence underlines the association between early life adversity and persistent alterations of neural, endocrine and immune functions that may be accompanied by a host of disease patterns such as ... [more ▼]

Growing evidence underlines the association between early life adversity and persistent alterations of neural, endocrine and immune functions that may be accompanied by a host of disease patterns such as chronic pain in later life. Neuropathy is a debilitating condition presenting a substantial cooccurrence with stress related disorders. Despite the established overlapping of biochemical pathways involved in the etiology of these disorders, the intricacy of their mutual interdependence remains. In this context, immunocompetent cells are largely affected during chronic stress and are a key factor in the sensitization of nociceptive dorsal horn neurons. The goal of the present study was to investigate the impact of maternal separation (MS), a wellestablished model of early life stress in rodents, on chronic constriction injury (CCI)induced neuropathic pain and to reveal the relevance of spinal microglia activation and proinflammatory cytokine regulation. For this purpose 12 groups of rats were exposed to different combinations of stress condition, CCIinjury and pharmacological treatment. Noxious sensitivity was tested during baseline conditions as well as during subsequent neuropathic and pharmacological treatment conditions. Von Frey hair and the cold plate tests were used for the assessment of mechanical and cold hyperalgesia/allodynia. Amphotericin B, a substance known to activate monocytes and macrophages in the periphery and microglial cells in the CNS was administered to subgroups of animals. At the end of the protocol, rats were sacrificed to assess microglial activation using qPCR and immunohistochemistry. Our main finding was that maternal separation led to a reduction of CCIrelated pain hypersensitivity (thermal and mechanical hyperalgesia/allodynia). We concomitantly observed a downregulation of Iba 1, mRNA a marker of microglial cells, and of IL1β mRNA, a proinflammatory cytokine that may be released by microglia. According to preliminary results, Amphotericin B in turn seemed to enhance CCI related pain sensitivity, possibly via an activation of microglia. Our results show that MS may lead to a reduction of neuropathy relatedpain in adult age. Stress related dampening of spinal microglial reactivity may play a critical role in this context. [less ▲]

Detailed reference viewed: 28 (8 UL)
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See detailA Product Line of Software Engineering Project Courses
Guelfi, Nicolas UL; Capozucca, Alfredo UL; Ries, Benoît UL

Poster (2017, November 08)

Detailed reference viewed: 41 (4 UL)
Peer Reviewed
See detailReliable Machine Learning for Networking: Key Concerns and Approaches
Hammerschmidt, Christian UL; Garcia, Sebastian; Verwer, Sicco et al

Poster (2017, October)

Machine learning has become one of the go-to methods for solving problems in the field of networking. This development is driven by data availability in large-scale networks and the commodification of ... [more ▼]

Machine learning has become one of the go-to methods for solving problems in the field of networking. This development is driven by data availability in large-scale networks and the commodification of machine learning frameworks. While this makes it easier for researchers to implement and deploy machine learning solutions on networks quickly, there are a number of vital factors to account for when using machine learning as an approach to a problem in networking and translate testing performance to real networks deployments successfully. This paper, rather than presenting a particular technical result, discusses the necessary considerations to obtain good results when using machine learning to analyze network-related data. [less ▲]

Detailed reference viewed: 59 (0 UL)
Peer Reviewed
See detailDoes physical learning environment matter? Effects after the move to a new campus on the perception of the quality of studies
Steffgen, Georges UL; Vesely, Jana; Pinto Costa, Andreia UL

Poster (2017, September 18)

The present study examined the effects of a move to a new physical learning environment – Belval Campus – on the students’ satisfaction with the course program in psychology. It was hypothesized that the ... [more ▼]

The present study examined the effects of a move to a new physical learning environment – Belval Campus – on the students’ satisfaction with the course program in psychology. It was hypothesized that the move to a new and modern University campus with better study facilities increases course climate, learning promotion, and skill acquisition. Participants were 538 undergraduate students who completed the Bachelor Evaluation Questionnaire, which assessed the perceived quality of the course program as well as five infrastructure and equipment aspects of the new campus. Findings show that students were more satisfied with the classrooms, the capacity of the rooms, and the library facilities, but there was no increase in perceived course climate, learning promotion, and skill acquisition of the students after 6 months nor after 18 months from the move. The implications of these findings for the need to change physical learning environments are discussed and recommendations for the design of learning environments are presented. [less ▲]

Detailed reference viewed: 37 (4 UL)
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See detailProject NUMTEST: Assessing basic number competence without language
Greisen, Max UL; Hornung, Caroline; Martin, Romain UL et al

Poster (2017, September 08)

While numerical skills are fundamental in modern societies, some estimated 5-7% of children suffer from a mathematical learning disorder, called developmental dyscalculia (DD). Nevertheless, universally ... [more ▼]

While numerical skills are fundamental in modern societies, some estimated 5-7% of children suffer from a mathematical learning disorder, called developmental dyscalculia (DD). Nevertheless, universally valid diagnostic instruments are still lacking, as all current DD test batteries are based on language instructions. Consequently, their measurements are tightly linked to the specific language context of test administration and thus their results cannot easily be compared across countries. Here we are showing results of the first two pilot studies of a research project that aims to develop a test for basic math abilities that does not rely on language instruction and minimizes language use. To this aim, video and animation based instructions were implemented on touchscreen devices. A first version of the tasks has been tested with two samples of first grade children in Luxembourg’s fundamental schools, of which half completed the same tasks with traditional verbal instructions. Our results indicate that performance in the experimental group was similar or better than the control group using verbal instructions. Relationships between linguistic background and the sample’s performance on one hand and qualitative usability aspects of nonverbal task instruction and tablet-pc use with young children will be discussed. [less ▲]

Detailed reference viewed: 34 (5 UL)
Peer Reviewed
See detailAvatar Sex Moderates Aggression in Violent Video Games, But Only for Women
Melzer, André UL; Schmidt, Alexander F.

Poster (2017, September 07)

Three studies tested findings reported by Yang, Huesmann, and Bushman (2014) that playing a male avatar in a violent video game leads to greater aggression than playing a female avatar in the same game ... [more ▼]

Three studies tested findings reported by Yang, Huesmann, and Bushman (2014) that playing a male avatar in a violent video game leads to greater aggression than playing a female avatar in the same game. The male avatar effect was confirmed in Study 1 (N=79) for post-game aggression: compared to playing a female character, participants who had played the male fighter in a violent mixed martials arts game chose more Hot Sauce for another participant who allegedly disliked spicy food. In contrast to Yang et al. (2014), however, the male avatar effect was qualified by participant sex, indicating that the effect was more strongly pronounced and only significant for female participants. A similar interaction effect was observed in Study 2 (N=76) and Study 3 (N=70) for in-game aggression: only female participants playing a male avatar showed a greater hit ratio in a mixed martials arts game (Study 2) or a greater number of attacks in a brawler game (Study 3) than their colleagues who played a female avatar. At this stage, the reason for this cross-gender effect is unclear. Given that games allow for behavior (i.e., aggression) independent of socially shared gender norms, we may speculate that for women, male avatars may provide the opportunity to “step out” of prevailing social norms regarding non-aggressive female behavior and adopt the role of the (hyper-)aggressive male. However, this hypothesis needs to be tested in future studies. All three studies additionally tested the mediating effect of male gender stereotype activation that was hypothesized by Yang et al. (2014). In addition to priming violent behavior, and in line with the General Aggression Model, the authors had speculated that playing the male avatar automatically activated male gender stereotypes (i.e., aggressive thoughts and behavior) which then caused aggressive behavior. In order to address this activation hypothesis, we designed an indirect cognitive measure of gender role identity using the Positive-Negative Sex-Role Inventory (PN-SRI: Berger & Krahé, 2013). After participants played the violent game, positive and negative aspects of masculinity and femininity were presented as word fragments in a five-minute response window in Study 1 and 2. Fragment completion rates served as indicators of cognitive activation of male stereotypes. In Study 3, participants used the intact PN-SRI gender attributes to rate the avatar after playing the game. However, both direct and indirect measures failed to corroborate the stereotype activation hypothesis in the present studies: word fragments related to male stereotypes were not completed more often than fragments related to female stereotypes (Study 1 and 2). Also, neither in-game aggression nor success in the game was associated with how masculine participants perceived their fighter (Study 3). At the present stage, thus, the mechanisms underlying the gender effect that participants respond differently when playing a male or female avatar in a violent video game remain unclear. [less ▲]

Detailed reference viewed: 187 (2 UL)
See detailEnergy and momentum distribution of fractional excitations in helical systems
Calzona, Alessio UL; Acciai, Matteo; Dolcetto, Giacomo UL et al

Poster (2017, September 05)

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See detailImpact of the Time of Diagnosis on Dyslexic Adolescents' Self-efficacy beliefs
Battistutta, Layla UL; Commissaire, Eva; Steffgen, Georges UL

Poster (2017, September)

Aim: Most of the research on self-efficacy in children with specific learning disorders has focused on inter-group comparisons, showing that these children hold lower self-efficacy scores than their ... [more ▼]

Aim: Most of the research on self-efficacy in children with specific learning disorders has focused on inter-group comparisons, showing that these children hold lower self-efficacy scores than their normally developing peers. As these lower scores might be due to a reduced access to self-efficacy sources (Hampton & Mason, 2003), this small-scale study (N=18) aimed to investigate whether the time of diagnosis might modulate the access to these sources within a group of dyslexic adolescents, either diagnosed in primary or secondary school but paired on chronological age and duration of remedial training. Methods: Mixed methods were employed by using general as well as academic and social self-efficacy scales, complemented by semi-structured interviews investigating students’ understanding and acceptance of their dyslexia. Results: The findings showed that early-diagnosed students hold higher general and academic scores. Further analyses regarding students’ personal statements revealed a statistically significant association between time of diagnosis and understanding as well as tolerance of dyslexia, indicating that early-diagnosed adolescents, compared to their late-diagnosed peers, have a more cohesive understanding and more adequate representations of their reading disorder as specific and non-stigmatizing, all the while being more tolerant and open about announcing their dyslexia to others. Conclusions: An early diagnosis of dyslexia is thus associated with a better understanding and acceptance of the disorder, possibly serving as a protective factor which can consequently contribute to higher general and academic self-efficacy scores. Hence, these findings not only extend the literature on self-efficacy beliefs in dyslexia by investigating the time of diagnosis, but also have important practical implications, highlighting the significance of an early diagnosis beyond the benefits of early rehabilitation as well as the potentially negative psychological consequences of a late diagnosis. [less ▲]

Detailed reference viewed: 79 (9 UL)
See detailThe relevance of verbal and visuo-spatial abilities for verbal number skills – what matters in 5 to 6 year olds?
Cornu, Véronique UL; Schiltz, Christine UL; Martin, Romain UL et al

Poster (2017, September)

The acquisition of verbal number skills, as defined by the meaningful use of number words, marks a milestone in numerical development. In the present study, we were particularly interested in the question ... [more ▼]

The acquisition of verbal number skills, as defined by the meaningful use of number words, marks a milestone in numerical development. In the present study, we were particularly interested in the question, whether verbal number skills are primarily verbal in nature, or if they call upon visuo-spatial processes, reflecting a spatial grounding of verbal number skills. 141 five- to six-year old children were tested on a range of verbal (i.e. vocabulary, phonological awareness and verbal working memory) and visuo-spatial abilities (i.e. spatial perception, visuo-motor integration and visuo-spatial working memory). We were particularly interested in the predictive role of these abilities for children’s verbal number skills (as measured by different counting and number naming tasks). In a latent regression model, basic visuo-spatial abilities, measured by spatial perception and visuo-motor integration, emerge as the most important predictor of verbal number skills. This gives raise to the assumption, that verbal number skills are, despite their verbal nature, spatially grounded in young children. [less ▲]

Detailed reference viewed: 74 (13 UL)
See detailTransport properties as a tool to study universal features of quench-induced dynamics in 1D systems
Calzona, Alessio UL; Gambetta, Filippo Maria; Cavaliere, Fabio et al

Poster (2017, August 14)

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See detailHuman in the Loop: Interactive Passive Automata Learning via Evidence-Driven State-Merging Algorithms
Hammerschmidt, Christian UL; State, Radu UL; Verwer, Sicco

Poster (2017, August)

We present an interactive version of an evidence-driven state-merging (EDSM) algorithm for learning variants of finite state automata. Learning these automata often amounts to recovering or reverse ... [more ▼]

We present an interactive version of an evidence-driven state-merging (EDSM) algorithm for learning variants of finite state automata. Learning these automata often amounts to recovering or reverse engineering the model generating the data despite noisy, incomplete, or imperfectly sampled data sources rather than optimizing a purely numeric target function. Domain expertise and human knowledge about the target domain can guide this process, and typically is captured in parameter settings. Often, domain expertise is subconscious and not expressed explicitly. Directly interacting with the learning algorithm makes it easier to utilize this knowledge effectively. [less ▲]

Detailed reference viewed: 21 (0 UL)
See detailEnergy and momentum distribution of fractional excitations in 1D counterpropagating systems
Calzona, Alessio UL; Acciai, Matteo; Dolcetto, Giacomo UL et al

Poster (2017, July 25)

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See detailA Global Vertical Land Movement Data Set from a Combination of Global Navigation Satellite System Solutions
Hunegnaw, Addisu UL; Teferle, Felix Norman UL; Abraha, Kibrom Ebuy UL et al

Poster (2017, July 13)

Coastal sea-level measurements by tide gauges provide the longest instrumental records of sea-levels with some stretching from the 19th century to present. The derived mean sea-level (MSL) records provide ... [more ▼]

Coastal sea-level measurements by tide gauges provide the longest instrumental records of sea-levels with some stretching from the 19th century to present. The derived mean sea-level (MSL) records provide sea-level relative to a nearby tide gauge benchmark (TGBM), which allows for the continuation of this record in time after, for example, equipment modifications. Any changes in the benchmark levels induced by vertical land movements (VLM) affect the MSL records and hence the computed sea-levels. In the past, MSL records affected by VLM were often excluded from further analyses or the VLM were modelled using numerical models of the glacial isostatic adjustment (GIA) process. Over the last two decades Global Navigation Satellite System (GNSS), in particular Global Positioning System (GPS), measurements at or close to tide gauges and the development of the associated processing strategies, have made it possible to obtain estimates of VLM in a geocentric reference system, such as the International Terrestrial Reference Frame release 2008 (ITRF2008) that approach the required accuracy for sea-level studies. Furthermore, the GPS-derived VLM estimates have been shown to improve estimates of sea-level change compared to those using the aforementioned GIA models as these models cannot predict local subsidence or uplift. The International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group has recently re-processed the global GNSS data set from its archive (1000+ stations for 1995-2014) to provide VLM estimates tuned for the sea-level community. To achieve this, five TIGA Analysis Centers (TAC) contributed their reprocessed global GPS network solutions to the WG, all employing the latest bias models and processing strategies in accordance with the second re-processing compaign (repro2) of the IGS. These individual solutions were then combined by the TIGA Combination Center (TCC) to produce, for the first time, a TIGA combined solution (Release 0.99). This combined solution allows an evaluation of each individual TAC solution while also providing a means to gauge the quality and reliability of the combined solution, which is generally regarded as superior to the individual TAC solutions. Using time series analysis methods, estimates of VLM can then be derived from the daily position estimates, which are sub-sequentially employed to investigate coastal sea-levels. In this study, we show results from the evaluation of the relevant solutions, provide an evaluation of the TIGA VLM estimates and give examples of their impact on sea-level estimates for selected tide gauges from around the world. The TAC and TIGA combined solutions, as well as the derived VLM data sets are available from the IGS TIGA WG and will be accessible through SONEL (www.sonel.org) in the near future. [less ▲]

Detailed reference viewed: 125 (15 UL)
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See detailCharge pumping through a polaron quantum dot
Haughian, Patrick UL; Yap, Han Hoe; Walter, Stefan et al

Poster (2017, July)

Nanoelectromechanical systems exhibit a rich phenomenology due to the interaction of electronic and mechanical degrees of freedom. If this interaction is sufficiently strong, it leads to drastic ... [more ▼]

Nanoelectromechanical systems exhibit a rich phenomenology due to the interaction of electronic and mechanical degrees of freedom. If this interaction is sufficiently strong, it leads to drastic suppression of conductance ("Franck-Condon blockade''). We show that this blockade can be exponentially lifted by application of an AC voltage. Multi-parameter drive protocols generate a pump current which enjoys the same enhancement. [less ▲]

Detailed reference viewed: 25 (0 UL)
Peer Reviewed
See detailDeniability in Quantum Cryptography
Atashpendar, Arash UL; Roenne, Peter UL; Ostrev, Dimiter UL et al

Poster (2017, June 14)

This poster describes ongoing work on deniability in quantum cryptography, an area of research that remains almost entirely unexplored in the quantum information processing literature. Deniability is a ... [more ▼]

This poster describes ongoing work on deniability in quantum cryptography, an area of research that remains almost entirely unexplored in the quantum information processing literature. Deniability is a well-known and fundamental concept in classical cryptography and it can be defined as the ability for the sender of a message to deny the contents of a message or the very act of having participated in an exchange, e.g. having sent the said message. We discuss deniability in the context of quantum key exchange and address a particular problem, first discovered by Donald Beaver, where he claims that all QKD protocols are undeniable. The claim is that while we do get a one-time pad (OTP) using QKD, it does not provide the property of key equivocation as it is expected in the Shannon sense for a OTP. Intuitively, this difficulty lies in the quantum channel alone and it has to do with the fact that in QKD, while we generate entropy by expanding an initially short pre-shared key into an arbitrary longer secret key, we do so by exchanging information over a quantum as well as a classical channel, which could potentially leave a binding transcript of Alice's decisions to the final secret key. This is in contrast with the implicit assumption that Eve knows nothing about how two given parties have established their shared OTP in the first place. We discuss the importance of deniability in cryptography and its wide range of applications, along with cryptographic primitives other than key exchange where deniability might be a desired property. Finally, we present a series of fundamental open questions in this area of research and discuss quantum cryptographic primitives that lend themselves to devising deniable protocols. [less ▲]

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See detailPoster: Impact of ground truth errors on Wi-Fi localization accuracy
Popleteev, Andrei UL

Poster (2017, June)

This study investigates the impact of small ground truth (GT) errors on indoor positioning systems based on Wi-Fi fingerprinting. The results demonstrate that even centimeter-scale GT deviations cause ... [more ▼]

This study investigates the impact of small ground truth (GT) errors on indoor positioning systems based on Wi-Fi fingerprinting. The results demonstrate that even centimeter-scale GT deviations cause severe degradation of measured localization accuracy. [less ▲]

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See detailProject NUMTEST: Assessing basic number competence without language
Greisen, Max UL; Hornung, Caroline UL; Martin, Romain UL et al

Poster (2017, May 31)

While numerical skills are fundamental in modern societies, some estimated 5-7% of children suffer from a mathematical learning disorder, called developmental dyscalculia (DD). Nevertheless, universally ... [more ▼]

While numerical skills are fundamental in modern societies, some estimated 5-7% of children suffer from a mathematical learning disorder, called developmental dyscalculia (DD). Nevertheless, universally valid diagnostic instruments are still lacking, as all current DD test batteries are based on language instructions. Consequently, their measurements are tightly linked to the specific language context of test administration and thus their results cannot easily be compared across countries. Here we are showing results of the first pilot study of a research project that aims to develop a test for basic math abilities that does not rely on language instruction and minimizes language use. To this aim, video and animation based instructions were implemented on touchscreen devices. A first version of the tasks has been tested with two samples of first grade children in Luxembourg’s fundamental schools, of which half completed the same tasks with traditional verbal instructions. Our results indicate that performance in the experimental group was similar or better than the control group using verbal instructions. Relationships between linguistic background and the sample’s performance on one hand and qualitative usability aspects of nonverbal task instruction and tablet-pc use with young children will be discussed. [less ▲]

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See detailParentalité en situation vulnérable: trajectoires de résilience familiale?
Dujardin, Céline UL

Poster (2017, May 19)

Le domaine de la protection de la jeunesse porte sur la prise en charge de situations familiales de vulnérabilité qui peuvent engendrer des impacts négatifs sur le développement de l'enfant. A l'inverse ... [more ▼]

Le domaine de la protection de la jeunesse porte sur la prise en charge de situations familiales de vulnérabilité qui peuvent engendrer des impacts négatifs sur le développement de l'enfant. A l'inverse, la notion de résilience permet la perspective sur une trajectoire familiale qui compense le danger pour le développement de l'enfant et le fonctionnement familial. La thèse est développée dans le but d'offrir un cadre de réflexion aux réponses élaborées aussi bien par les services d'aides que par les familles elles-mêmes face aux difficultés rencontrées, tenant compte des particularités liées au contexte luxembourgeois. [less ▲]

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See detailA PetriNet Mechanism for OLAP in NUMA
Dominico, Simone; Almeida, Eduardo Cunha de; Meira, Jorge Augusto UL

Poster (2017, May 15)

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See detailLuxemburg und der Studiengang der Sozialen Arbeit
Böwen, Petra UL; Dujardin, Céline UL; Straus, Liz UL

Poster (2017, May 10)

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See detailThe Multi-Generation Repackaging Hypothesis
Li, Li UL; Bissyande, Tegawendé François D Assise UL; Bartel, Alexandre UL et al

Poster (2017, May)

App repackaging is a common threat in the Android ecosystem. To face this threat, the literature now includes a large body of work proposing approaches for identifying repackaged apps. Unfortunately ... [more ▼]

App repackaging is a common threat in the Android ecosystem. To face this threat, the literature now includes a large body of work proposing approaches for identifying repackaged apps. Unfortunately, although most research involves pairwise similarity comparison to distinguish repackaged apps from their “original” counterparts, no work has considered the threat to validity of not being able to discover the true original apps. We provide in this paper preliminary insights of an investigation into the Multi-Generation Repackaging Hypothesis: is the original in a repackaging process the outcome of a previous repackaging process? Leveraging the Androzoo dataset of over 5 million Android apps, we validate this hypothesis in the wild, calling upon the community to take this threat into account in new solutions for repackaged app detection. [less ▲]

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See detailUnderstanding Android App Piggybacking
Li, Li UL; Li, Daoyuan UL; Bissyande, Tegawendé François D Assise UL et al

Poster (2017, May)

The Android packaging model offers adequate opportunities for attackers to inject malicious code into popular benign apps, attempting to develop new malicious apps that can then be easily spread to a ... [more ▼]

The Android packaging model offers adequate opportunities for attackers to inject malicious code into popular benign apps, attempting to develop new malicious apps that can then be easily spread to a large user base. Despite the fact that the literature has already presented a number of tools to detect piggybacked apps, there is still lacking a comprehensive investigation on the piggybacking processes. To fill this gap, in this work, we collect a large set of benign/piggybacked app pairs that can be taken as benchmark apps for further investigation. We manually look into these benchmark pairs for understanding the characteristics of piggybacking apps and eventually we report 20 interesting findings. We expect these findings to initiate new research directions such as practical and scalable piggybacked app detection, explainable malware detection, and malicious code location. [less ▲]

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See detailEvaluation of ERA-Interim for tropospheric delay and water vapour estimation in different climate zones using ground-based GNSS observations
Ahmed, Furqan; Hunegnaw, Addisu UL; Teferle, Felix Norman UL et al

Poster (2017, April 27)

Tropospheric delay and integrated water vapour (IWV) derived from climate reanalysis models, such as that of the European Centre for Medium-range Weather Forecasts (ECMWF) namely the ECMWF ReAnalysis ... [more ▼]

Tropospheric delay and integrated water vapour (IWV) derived from climate reanalysis models, such as that of the European Centre for Medium-range Weather Forecasts (ECMWF) namely the ECMWF ReAnalysis-Interim (ERA-Interim), are widely used in many geodetic and atmospheric applications. Therefore, it is of interest to assess the quality of these reanalysis products using available observations. Observations from Global Navigation Satellite Systems (GNSS) are, as of now, available for a period of over 2 decades and their global availability make it possible to validate the zenith total delay (ZTD) and IWV obtained from climate reanalysis models in different geographical and climatic regions. In this study, a 5-year long homogeneously reprocessed GNSS data set based on double differenced positioning strategy and containing over 400 globally distributed ground-based GNSS stations has been used as a reference to validate the ZTD estimates obtained from the ERA-Interim climate reanalysis model in 25 different climate zones. It has been studied how the difference between the ERA-Interim ZTD and the GNSS-derived ZTD varies with respect to the different climate zones as well as the topographic variations in a particular climate zone. Periodicity in the ZTD residuals in different climate zones has been analyzed. Furthermore, the variation of the ZTD differences with respect to latitude has been presented. Finally, for one GNSS station in each of the 25 climate zones, IWV derived from ERA-Interim has been compared to the IWV derived using GNSS observations. [less ▲]

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See detailA New Global Vertical Land Movement Data Set from the TIGA Combined
Hunegnaw, Addisu UL; Teferle, Felix Norman UL; Abraha, Kibrom Ebuy UL

Poster (2017, April 23)

Globally averaged sea level has been estimated from the network of tide gauges installed around the world since the 19th century. These mean sea level (MSL) records provide sea level relative to a nearby ... [more ▼]

Globally averaged sea level has been estimated from the network of tide gauges installed around the world since the 19th century. These mean sea level (MSL) records provide sea level relative to a nearby tide gauge benchmark (TGBM), which allows for the continuation of the instrumental record in time. Any changes in the benchmark levels, induced by vertical land movements (VLM) affect the MSL records and hence sea level estimates. Over the last two decades sea level has also been observed using satellite altimeters. While the satellite observations are globally more homogeneous providing a picture of sea level not confined to coastlines, they require the VLM-corrected MSL records for the bias calibration of instrumental drifts. Without this calibration altimeter instruments from different missions cannot be combined. GPS has made it possible to obtain highly accurate estimates of VLM in a geocentric reference frame for stations at or close to tide gauges. Under the umbrella of the International GNSS Service (IGS), the Tide Gauge Benchmark Monitoring (TIGA) Working Group (WG) has been established to apply the expertise of the GNSS community to solving issues related to the accuracy and reliability of the vertical component to provide estimates of VLM in a well-defined global reference frame. To achieve this objective, five TIGA Analysis Centers (TACs) contributed re-processed global GPS network solutions to TIGA, employing the latest bias models and processing strategies in accordance with the second re-processing campaign (repro2) of the IGS. These solutions include those of the British Isles continuous GNSS Facility – University of Luxembourg consortium (BLT), the German Research Centre for Geosciences (GFZ) Potsdam, the German Geodetic Research Institute (DGF) at the Technical University of Munich, Geoscience Australia (AUT) and the University of La Rochelle (ULR). In this study we present to the sea level community an evaluation of the VLM estimates from the first combined solution from the IGS TIGA WG. The TAC solutions include more than 700 stations and span the common period 1995-2014. The combined solution was computed by the TIGA Combination Centre (TCC) at the University of Luxembourg, which used the Combination and Analysis of Terrestrial Reference Frame (CATREF) software package for this purpose. This first solution forms Release 1.0 and further releases will be made available after further reprocessing campaigns. We evaluate the combined solution internally using the TAC solutions and externally using solutions from the IGS and the ITRF2008. The derived VLM estimates have undergone an initial evaluation and should be considered as the primary TIGA product for the sea level community to correct MSL records for land level changes [less ▲]

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See detailMechanical characterisation of alkali activated clay - based geopolymer binder made out of gravel wash mud
Thapa, Vishojit Bahadur UL; Waldmann, Danièle UL; Wagner, Jean-Frank et al

Poster (2017, April 03)

One of the most promising cement alternatives are geopolymer cements. The term “geopolymer” was mentioned for the first time by Davidovits and classifies all forms of inorganic polymeric material ... [more ▼]

One of the most promising cement alternatives are geopolymer cements. The term “geopolymer” was mentioned for the first time by Davidovits and classifies all forms of inorganic polymeric material synthesised by chemical reaction of aluminosilicates and an alkaline activating solution. The production of geopolymer binder comprises in two main procedures: calcination and geopolymerisation. The synthesised geopolymer shows interesting characteristics like good mechanical properties, high strength and good durability. [less ▲]

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See detailTesting measurement Invariance in a CFA framework – State of the art
Sischka, Philipp UL

Poster (2017, March 31)

In recent years, several studies have stressed out the importance to guarantee the comparability of theoretical constructs (i.e. measurement invariance) in the compared units (e.g., groups or time points ... [more ▼]

In recent years, several studies have stressed out the importance to guarantee the comparability of theoretical constructs (i.e. measurement invariance) in the compared units (e.g., groups or time points) in order to conduct comparative analyses (e.g. Harkness, Van de Vijver, & Mohler, 2003; Meredith, 1993; Vandenberg, & Lance, 2000). If one does not test for measurement invariance (MI) or ignores lack of invariance, differences between groups in the latent constructs cannot be unambiguously attributed to ‘real’ differences or to differences in the measurement attributes. One approach to test for MI is in a confirmatory factor analysis (CFA) framework. In this framework, MI is usually tested with a series of model comparisons that define more and more stringent equality constraints. The presentation will be about new developments in the MI-CFA framework. Among other things, the presentation tries to answer the following questions: • Which scale setting method to use (marker variable, fixed factor or effect coding method) when testing for MI? • Should a top-down- or bottom-up-approach be used? • How to test MI with a large number of groups (>30)? • What are the possibilities to evaluate whether MI exists (e.g., statistical significance of the ∆² after Bonferroni adjustment, changes in approximate fit statistics, magnitude of difference between the parameter estimates)? • How to determine confidence intervals for fit indices? • Can MI be graphically analyzed? • How can be dealt with non-invariance? These questions will be tried to answered by an application to a real world dataset (N ~ 40.000), with a one-factor/five indicator model of a well-being scale tested in 35 groups. [less ▲]

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See detailThe influence of Forced Answering on response behavior in Online Surveys: A reactance effect?
Sischka, Philipp UL; Mergener, Alexandra; Neufang, Kristina Marliese et al

Poster (2017, March 16)

Relevance: Recent studies have shown that the use of the forced answering (FA) option in online surveys results in reduced data. They especially examined that forcing respondents to answer questions in ... [more ▼]

Relevance: Recent studies have shown that the use of the forced answering (FA) option in online surveys results in reduced data. They especially examined that forcing respondents to answer questions in order to proceed through the questionnaire leads to higher dropout rates and lower answer quality. However, no study researched the psychological mechanism behind the correlation of FA on dropout and data quality before. This response behavior has often been interpreted as psychological reactance reaction. So, the Psychological Reactance Theory (PRT) predicts that reactance appears when an individuals’ freedom is threatened and cannot be directly restored. Reactance describes the motivation to restore this loss of freedom. Respondents could experience FA as a loss of freedom, as (s)he is denied the choice to leave a question unanswered. According to PRT, possible reactions in this situation might be to quit survey participation, to fake answers or to show satisficing tendencies. Research content: This study explores the psychological mechanism that effects response behavior in FA condition (compared to non-FA- condition). Our major hypothesis is that forcing respondents to answer will cause reactance, which turns into increasing dropout rates, decreasing answer quality and a satisficing behavior. Methods and Data: We used an online survey-experiment with two conditions (forced and non-forced answering instructions). The sample consists of 914 participants. Throughout the whole questionnaire, a dropout button was implemented on each page. In both conditions, this button led to the same page that fully compliant participants reached at the end of the questionnaire. Reactance was measured with a self-constructed four-item reactance scale. To determine answer quality, we used self-report for faking as well as the analysis of answers to open ended questions. Results: Zero-order effects showed that FA increased state reactance and questionnaire dropout as well as it reduced answer length in open-ended questions. Mediation analysis (Condition -> state reactance -> dropout/answer quality) supported the hypothesis of reactance as an underlying psychological mechanism behind negative FA effects on data quality. Added Value: This is the first study which offers statistical evidence for the often proposed reactance effect influencing response behavior. This offers a base for a deeper psychological reflection of the use of the FA-option. [less ▲]

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See detailVisuo-spatial abilities are key for children’s verbal number skills
Cornu, Véronique UL; Martin, Romain UL; Hornung, Caroline UL

Poster (2017, February 22)

Verbal number skills (i.e. counting and number naming) are milestones in numerical development. The aim of the present study was to clarify the role of different verbal abilities (VA) and visuo-spatial ... [more ▼]

Verbal number skills (i.e. counting and number naming) are milestones in numerical development. The aim of the present study was to clarify the role of different verbal abilities (VA) and visuo-spatial abilities (VSA) in the development of these verbal number skills in kindergarten. We recruited 152 children (mean age: 5.8 years) and administered different measures of VA (e.g. phonological awareness, pseudoword recall) and of VSA (e.g. spatial perception, copying) to assess their contribution to verbal number skills. Firstly, we computed two independent regression models, a “VA only” model explaining 23% of variance, and a “VSA only” model explaining 38% of variance. Adding verbal measures to the “VSA only” model does not lead to a significant increase in R2. Our results show that VSA, rather than VA, contribute to a larger extent to children’s verbal number skills. Intriguingly, the development of verbal number skills builds on VA, but more importantly on VSA. These results are potentially informative for the conception early mathematics interventions. [less ▲]

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See detailProject NUMTEST; Assessing basic number competence without language
Greisen, Max UL; Schiltz, Christine UL; Hornung, Caroline UL et al

Poster (2017, February 20)

While numerical skills are fundamental in modern societies, some estimated 5-7% of children suffer from a mathematical learning disorder, called developmental dyscalculia (DD). Nevertheless, universally ... [more ▼]

While numerical skills are fundamental in modern societies, some estimated 5-7% of children suffer from a mathematical learning disorder, called developmental dyscalculia (DD). Nevertheless, universally valid diagnostic instruments are still lacking, as all current DD test batteries are based on language instructions. Consequently their measurements are tightly linked to the specific language context of test administration and thus their results cannot easily be compared across countries. The present study is the first pilot study of a research project that aims to develop a test for basic math abilities that does not rely on language instruction and minimizes language use. To this aim, video and animation based instructions were implemented on touchscreen devices. A first version of the application has been tested with a sample of first grade children in Luxembourg’s fundamental schools, of which half used the same application but with traditional German instructions. First results indicate that performance in the experimental group was similar to the control group using verbal instructions. Relationships between linguistic background and the sample’s performance on one hand and qualitative usability aspects of nonverbal task instruction and tablet use with young children will be discussed. [less ▲]

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See detailAnalyzing the relation between commuting satisfaction and residential choices using discrete choice theory and structural equation modeling
Sprumont, François UL; Astegiano, Paola; Viti, Francesco UL

Poster (2017, January)

The concept of travelling satisfaction is gaining more and more interest in the transportation field. While increasing travellers’ satisfaction should be a goal of policy makers and practitioners, a drop ... [more ▼]

The concept of travelling satisfaction is gaining more and more interest in the transportation field. While increasing travellers’ satisfaction should be a goal of policy makers and practitioners, a drop in commuting satisfaction might lead to switch from one mode to another. Objective trip characteristics (time, cost, mode) as well as other elements such as mode attitude, lifestyle, etc. affect travel satisfaction rating. Despite an extensive literature on travel satisfaction determinants, often, the interaction between the studied determinants is overlooked. The main aim of this paper is to quantify the impact (both direct and indirect) of residential choices on the home-to-work stated travelling satisfaction. Methodologically, a Discrete Choice Theory approach (via the well-known concept of the utility Logsum) and a Partial Least Square Structural Equation Modelling (PLS-SEM) approach have been used and compared. Results of both modelling approaches show that the direct effect of residential choices on commuting satisfaction is negligible compared to individuals’ external factors such as trip characteristics. However, using the PLS-SEM approach, indirect effects of residential choices on commuting satisfaction can be quantified [less ▲]

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See detailAssessing the cerebral correlates of non-symbolic number processing with fast periodic visual stimulation
Guillaume, Mathieu UL; Mejias, Sandrine; Rossion, Bruno et al

Poster (2017)

Some authors recently challenged the claim that numerical processes specifically handle non-symbolic magnitudes and they alternately suggested that general visual and/or control executive processes could ... [more ▼]

Some authors recently challenged the claim that numerical processes specifically handle non-symbolic magnitudes and they alternately suggested that general visual and/or control executive processes could explain performance in number comparison tasks. To further investigate this issue, we set up an EEG paradigm in which we recorded neural responses to the passive viewing of different arrays of basic visual forms. The stimuli sequence followed a fast and sinusoidal contrast modulation at the frequency of 10Hz (ten items per second). Visual properties of elements randomly changed from item to item, but their number was manipulated: in a control condition, arrays always contained the same number, and in the experimental conditions, the number periodically changed (each eight iteration, at 1.25Hz). We varied the numerical ratio between the frequent and the rare number throughout the experimental conditions. We recorded significant responses on occipital and parietal electrodes to the oddball frequency and its harmonics during our experimental conditions. Crucially, the strength of the signal was proportionally larger when the numerical ratio was larger. The results suggest that implicit and passive viewing of quick sequence of arrays was sufficient to automatically elicit neural synchronisation to numerical magnitudes without any explicit involvement of higher general cognitive processes. [less ▲]

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See detailComparison of Several RANS Modelling for the Pavia TRIGA Mark II Research Reactor
Introini, Carolina; Baroli, Davide UL; Peters, Bernhard UL

Poster (2017)

In this study, a detailed analysis of the turbulent regime within the core of the Pavia TRIGA Mark II reactor is perfomed by means of an in-depth comparison of the RAS (Reynolds-Averaged Simulation ... [more ▼]

In this study, a detailed analysis of the turbulent regime within the core of the Pavia TRIGA Mark II reactor is perfomed by means of an in-depth comparison of the RAS (Reynolds-Averaged Simulation) turbulence models implemented in OpenFOAM. Aim of this analysis is to give some important information with respect to the flow regime within the core. The performance of the various models is tested against a LES (Large Eddy Simulation) of the innermost channel. [less ▲]

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See detailLangzeitkonsequenzen von frühkindlichem Stress
Schaan, Violetta UL; Schulz, André UL; Vögele, Claus UL

Poster (2017)

Traumatische Belastungen während der Kindheit können das Risiko für die Entwicklung unsicherer Bindungsstile erhöhen, die bereits mit langfristigen psychischen und körperlichen Gesundheitsproblemen in ... [more ▼]

Traumatische Belastungen während der Kindheit können das Risiko für die Entwicklung unsicherer Bindungsstile erhöhen, die bereits mit langfristigen psychischen und körperlichen Gesundheitsproblemen in Beziehung gebracht wurden. Die zugrundeliegenden Prozesse sind allerdings noch weitestgehend unklar. Wir präsentieren zwei Studien, die den Zusammenhang zwischen kindlichem Stress und Gesundheit im Erwachsenenalter sowie Körperwahrnehmung und Gedächtnisfähigkeit untersuchen. In der ersten Studie nahmen 199 Teilnehmer an einer Onlineumfrage teil, bei der Gesundheit, frühkindliches Trauma, Resilienz und Zurückweisungssensitivität gemessen wurden. Teilnehmer mit geschiedenen Eltern berichteten erhöhte psychische Belastungswerte, kindliches Trauma, Zurückweisungssensitivität und weniger Resilienz. Die Beziehung zwischen elterlicher Scheidung und psychischer Gesundheit konnte vollständig durch diese vier Faktoren erklärt werden (Varianzaufklärung 44%). In einer zweiten Studie wurden bei 60 Teilnehmern verschiedene Selbstbericht-Parameter erhoben und die Gedächtnis- und Interozeptionsfähigkeit vor und nach einem Stresstest untersucht. Erwachsene mit einer Vorgeschichte von elterlicher Trennung berichteten mehr bindungsbezogene Angst und Vermeidung als Kontrollpersonen. Das Erlebnis einer elterlichen Scheidung war negativ mit der Gedächtnisleistung nach dem Stresstest korreliert. Weiterhin weisen die Ergebnisse auf einen quadratischen Zusammenhang zwischen Stress und Interozeptionsfähigkeit hin. [less ▲]

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See detailSingle station Monitoring of Volcanoes Using Seismic ambient noise
De Plaen, Raphaël UL; Lecocq, Thomas; Caudron, Corentin et al

Poster (2016, December 16)

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See detailElastography under uncertainty
Hale, Jack UL; Farrell, Patrick; Bordas, Stéphane UL

Poster (2016, December 12)

Detailed reference viewed: 138 (11 UL)
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See detailReal-time error control for surgical simulation
Bui, Huu Phuoc UL; Tomar, Satyendra UL; Courtecuisse, Hadrien et al

Poster (2016, December 12)

Objective: To present the first real-time a posteriori error-driven adaptive finite element approach for real-time simulation and to demonstrate the method on a needle insertion problem. Methods: We use ... [more ▼]

Objective: To present the first real-time a posteriori error-driven adaptive finite element approach for real-time simulation and to demonstrate the method on a needle insertion problem. Methods: We use corotational elasticity and a frictional needle/tissue interaction model based on friction. The problem is solved using finite elements within SOFA. The refinement strategy relies upon a hexahedron-based finite element method, combined with a posteriori error estimation driven local $h$-refinement, for simulating soft tissue deformation. Results: We control the local and global error level in the mechanical fields (e.g. displacement or stresses) during the simulation. We show the convergence of the algorithm on academic examples, and demonstrate its practical usability on a percutaneous procedure involving needle insertion in a liver. For the latter case, we compare the force displacement curves obtained from the proposed adaptive algorithm with that obtained from a uniform refinement approach. Conclusions: Error control guarantees that a tolerable error level is not exceeded during the simulations. Local mesh refinement accelerates simulations. Significance: Our work provides a first step to discriminate between discretization error and modeling error by providing a robust quantification of discretization error during simulations. [less ▲]

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See detailError analysis of Tide Gauge Benchmark Monitoring (TIGA) Analysis Center stacked solutions
Hunegnaw, Addisu UL; Teferle, Felix Norman UL; Abraha, Kibrom Ebuy UL et al

Poster (2016, December 12)

In 2013 the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group (WG) started their reprocessing campaign, which proposes to re-analyze all relevant Global Positioning ... [more ▼]

In 2013 the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group (WG) started their reprocessing campaign, which proposes to re-analyze all relevant Global Positioning System (GPS) observations from 1995 to the end of 2013. This re-processed dataset will provide high quality estimates of land motions, enabling regional and global high-precision geophysical/geodetic studies. Several of the individual TIGA Analysis Centers (TACs) have completed processing the full history of GPS observations recorded by the IGS global network, as well as, many other GPS stations at or close to tide gauges, which are available from the TIGA data center at the University of La Rochelle (www.sonel.org). The TAC solutions contain a total of over 700 stations. This study focuses on the evaluations of any systematic error present in the three TIGA analysis center (TAC) SINEX solutions: the British Isles continuous GNSS Facility – University of Luxembourg consortium (BLT), the GeoForschungsZentrum (GFZ) Potsdam, and of the University of La Rochelle (ULR). We have analyzed the residual position time series of the individual TAC a combination of automatic and manual discontinuity identification, applying a post-seismic deformation model adopted from ITRF2014 for those stations that are affected by earthquakes, followed by the stacking of the daily solution of the individual TAC into a long term linear frame. We have carried out the error analysis using the Combination and Analysis of Terrestrial Reference Frame (CATREF) software package. The TIGA Combination Centre (TCC) at the University of Luxembourg (UL) is responsible for providing a combined solution with a global set of vertical land movement estimates. [less ▲]

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See detailOn the Impact of Multi-GNSS Solutions on Satellite Products and Positioning
Abraha, Kibrom Ebuy UL; Teferle, Felix Norman UL; Hunegnaw, Addisu UL et al

Poster (2016, December 12)

In Global Navigation Satellite System (GNSS) coordinate time series unrecognised errors and un-modelled (periodic) effects may bias non-linear motions induced by geophysical signals. Those spurious ... [more ▼]

In Global Navigation Satellite System (GNSS) coordinate time series unrecognised errors and un-modelled (periodic) effects may bias non-linear motions induced by geophysical signals. Those spurious signals can be caused either due to un-modelled long periodic signals or propagation of sub-daily signals into the time series. Understanding and mitigating these errors is vital to reduce biases and on revealing subtle geophysical signals. Mostly, the spurious signals are caused by unmodelled errors which occur due to the draconitic years, satellite ground repeats and absorption into resonant GNSS orbits. Accordingly, different features can be observed in GNSS-derived products from different single-GNSS or combined-GNSS solutions. To assess the nature of periodic signals on station coordinate time series Precise Point Positioning (PPP) solutions are generated using the Bernese GNSS Software V5.2. The solutions consider only GPS, only GLONASS or combined GPS+GLONASS (GNSS) observations. We assess the periodic signals of station coordinates computed using the combined International GNSS Service (IGS) and four of its Analysis Centers (ACs) products. [less ▲]

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See detailImage to analysis pipeline: single and double balloons kyphoplasty
Baroli, Davide UL; Hauseux, Paul UL; Hale, Jack UL et al

Poster (2016, December 12)

In this work, we present a semi-automatic pipeline from image to simulation of a patient fractured vertebra after the kyphoplastic augmentation with two balloons. In this procedure, the CT-scan medical ... [more ▼]

In this work, we present a semi-automatic pipeline from image to simulation of a patient fractured vertebra after the kyphoplastic augmentation with two balloons. In this procedure, the CT-scan medical image are pre-processed using open-source software Slice3D for segmentation and 3D reconstruction operation. Then, using geometric processing the 3D surface geometry is enhanced to avoid degenerate element and trigging phenomena on vertebra and cement area. We perform a finite element analysis to evaluate the risk of subsequent vertebral fracture. Finally using Monte-Carlo technique, we assess the propagation of uncertainty of material parameter on the evaluation of this risk. Based on the developed semi-automatic pipelines, it is possible to perform a patient-specific simulation that assesses the successful of kyphoplasty operation. [less ▲]

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See detailBayesian inference for parameter identification in computational mechanics
Rappel, Hussein UL; Beex, Lars UL; Hale, Jack UL et al

Poster (2016, December 12)

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Peer Reviewed
See detailPoster: LuST-LTE: A Simulation Package for Pervasive Vehicular Connectivity
Derrmann, Thierry UL; Faye, Sébastien UL; Frank, Raphaël UL et al

Poster (2016, December 08)

Recent technological advances in communication technology have provided new ways to understand human mobility. Connected vehicles with their rising market penetration are particularly representative of ... [more ▼]

Recent technological advances in communication technology have provided new ways to understand human mobility. Connected vehicles with their rising market penetration are particularly representative of this trend. They become increasingly interesting, not only as sensors, but also as participants in Intelligent Transportation System (ITS) applications. More specifically, their pervasive connectivity to cellular networks enables them as passive and active sensing units. In this paper, we introduce LuST-LTE, a package of open-source simulation tools that allows the simulation of vehicular traffic along with pervasive LTE connectivity. [less ▲]

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See detailUncertainty quantification for soft tissue biomechanics
Hauseux, Paul UL; Hale, Jack UL; Bordas, Stéphane UL

Poster (2016, December)

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See detailGame-Theoretic Framework for Integrity Verification in Computation Outsourcing
Pejo, Balazs UL; Tang, Qiang

Poster (2016, November 03)

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See detailFacteurs psychologiques, cognitifs et les influences contextuelles dans la douleur et la souffrance liée à la douleur
Bustan, Smadar; Gonzalez-Roldan, Ana Maria; Schommer, Christoph UL et al

Poster (2016, November)

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See detailEfficient Learning of Communication Profiles from IP Flow Records
Hammerschmidt, Christian UL; Marchal, Samuel; Pellegrino, Gaetano et al

Poster (2016, November)

The task of network traffic monitoring has evolved drastically with the ever-increasing amount of data flowing in large scale networks. The automated analysis of this tremendous source of information ... [more ▼]

The task of network traffic monitoring has evolved drastically with the ever-increasing amount of data flowing in large scale networks. The automated analysis of this tremendous source of information often comes with using simpler models on aggregated data (e.g. IP flow records) due to time and space constraints. A step towards utilizing IP flow records more effectively are stream learning techniques. We propose a method to collect a limited yet relevant amount of data in order to learn a class of complex models, finite state machines, in real-time. These machines are used as communication profiles to fingerprint, identify or classify hosts and services and offer high detection rates while requiring less training data and thus being faster to compute than simple models. [less ▲]

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See detailBehavioral Clustering of Non-Stationary IP Flow Record Data
Hammerschmidt, Christian UL; Marchal, Samuel; State, Radu UL et al

Poster (2016, October)

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See detailPOSTER: Fingerprinting Tor Hidden Services
Mitseva, Asya UL; Panchenko, Andriy UL; Lanze, Fabian et al

Poster (2016, October)

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See detailDifferent aspects of spatial skills and their relation to early mathematics
Cornu, Véronique UL; Hornung, Caroline UL; Schiltz, Christine UL et al

Poster (2016, September 29)

We aimed at investigating the predictive role of spatial skills for arithmetic and number line estimation in kindergarten children (N = 125). Several studies highlighted the relation between spatial ... [more ▼]

We aimed at investigating the predictive role of spatial skills for arithmetic and number line estimation in kindergarten children (N = 125). Several studies highlighted the relation between spatial skills and mathematics. However, due to their non-unitary nature, different aspects of spatial skills need to be differentiated to clarify the relative importance of different aspects of spatial skills for mathematics. In the present study, at time 1, a spatial perception task, a spatial visualization task and visuo-motor integration task were administered to assess different aspects of spatial skills. Furthermore we assessed domain-specific skills and verbal domain-general skills. Four months later, the same children performed an arithmetic task and a number line estimation task to evaluate how the abilities measured at time 1 predict early mathematics. Hierarchical regression modelling revealed that children’s performance on the spatial perception task was predictive of their performance in both arithmetic and number line estimation, whereas visuo-motor integration and knowledge of the Arabic numerals significantly predicted arithmetic. The predictive relation between spatial perception and arithmetic was partially mediated by the number line estimation task. Our findings emphasize the role of spatial skills, notably spatial perception, in mathematical development. These results reveal the importance to differentiate within the construct of spatial skills when studying their role in numerical development. The development and implementation of pre-school interventions fostering children’s spatial perception and visuo-motor integration might thus be a promising approach for providing children with a sound foundation for later mathematical learning. [less ▲]

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See detailAn evaluation of low-cost consumer-grade UAS systems for 3D reality capture
Backes, Dietmar UL; Teasdale, Oliver; Eloff, Jacques

Poster (2016, September 22)

During the last years, small lightweight and low cost remotely piloted aerial systems (RPAS) commonly referred as Drones have rapidly developed into capable low-cost Unmanned Aerial Systems (UAS). Fuelled ... [more ▼]

During the last years, small lightweight and low cost remotely piloted aerial systems (RPAS) commonly referred as Drones have rapidly developed into capable low-cost Unmanned Aerial Systems (UAS). Fuelled by a vibrant community of scientists, professionals and hobby enthusiasts enabling technologies have matured quickly, and prices of consumer grade as well as semi-professional systems fell sharply. Especially multirotor vertical take-off and landing (VTOL) UAS have proven to be versatile and flexible platforms which can be equipped with a range of sensors capable of capturing aerial data for a variety of 2D and 3D mapping applications. Consumer grade, low weight systems as the DJI Phantom or 3DR Solo have a limited payload and can carry low weight action cameras like the GoPro Hero models which are capable of collecting video as well as still RGB and near-infrared imagery. Applying traditional Photogrammetric methods to imagery from low-cost UAS systems proved complex and impractical in the past. However modern the state-of-the-art structure from motion algorithms implemented in off the shelf software packages (sometimes referred as new Photogrammetry), cloud processing environments and available via open source libraries promise to generate dense 3D point clouds, textured models and orthomosaics in high quality and without much effort. How accurate and how reliable are data products generated from such systems? Expanding from a preliminary study (BACKES & TEASDALE 2015) we review the every progressing capabilities and features of COTS (commercial of the shelf) user and semi-professional UAS systems under the aspects of deployable sensors, ease of use, reliability as well as safety. We show the workflow from flight planning, data collection to dense pointclould matching using a range of software products. The resulting point clouds are evaluated and benchmarked using a highly accurate and dense reference data acquired via geodetic terrestrial survey and Laserscanning. The results of this evaluations allow conclusions on the current accuracy capabilities of this such low-cost systems. [less ▲]

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See detailLiquid Transport in Bi-disperse Particle Beds
Wu, Mingqiu UL; Khinast, Khinast; Radl, Stefan

Poster (2016, September 15)

Flow of highly saturated wet granular matter is encountered in wide range of engineering application, particularly in the pharmaceutics, food industry and energy sector , in addition, granular particles ... [more ▼]

Flow of highly saturated wet granular matter is encountered in wide range of engineering application, particularly in the pharmaceutics, food industry and energy sector , in addition, granular particles beds usually compose of various of particle properties (i.e.,, shape, size, density, etc.) and it well know that particle size polydispersity and shape significantly influence on the transport of mass and liquid in a fluidized bed system. [less ▲]

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See detailCoP Luxembourg
Böwen, Petra UL; Dujardin, Céline UL; Pissinger, Simone

Poster (2016, September 05)

Detailed reference viewed: 83 (10 UL)
See detailEnergy fractionalization after single electron injection into an interacting helical liquid
Calzona, Alessio UL; Acciai, Matteo; Carrega, Matteo et al

Poster (2016, September)

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Peer Reviewed
See detailAge modulates the relation between number-space associations and arithmetical abilities in elementary school children
Georges, Carrie UL; Hoffmann, Danielle UL; Schiltz, Christine UL

Poster (2016, September)

Evidence for number-space associations comes from the SNARC effect, consisting in faster RTs to small/large digits with the left/right hand respectively. In adults, number-space associations relate to ... [more ▼]

Evidence for number-space associations comes from the SNARC effect, consisting in faster RTs to small/large digits with the left/right hand respectively. In adults, number-space associations relate to mathematical proficiency in that individuals with weaker arithmetic performances feature stronger SNARC effects (Hoffmann et al., 2014). However, in children far less is known about number-space associations and how they affect arithmetic performance. We therefore investigated the relationship between the classical parity SNARC effect and mathematical proficiency, assessed using the Heidelberger Rechentest, in elementary school children aged 8-11 years (n=55, mean=9.5). Overall, the parity SNARC regression slopes (-11.37, p<.001) negatively correlated with HRT arithmetical (r=-.28, p=.04; even when controlling for parity judgment RTs: r=-.37, p=.01), but not HRT visuo-spatial subscale scores (r=-.03, p=.82), indicating better arithmetic performances with stronger number-space associations. However, this relation was significantly moderated by age, since the interaction between the parity SNARC effect and age accounted for a significant proportion of the variance in HRT arithmetical scores (ΔR2=.07, b=0.26, t(51)=2.29, p=.03). A significant negative association was observed only in younger children (b=-0.35, t=-3.49, p=.001) aged below 9.5 years (n=29), while the SNARC effect did not relate to arithmetic performance in the remaining older children. This suggests that number-space associations are beneficial for arithmetic performance at relatively early stages of mathematical learning. During the course of mathematical development in childhood, number-space associations then turn superfluous for arithmetic achievement until they possibly become interfering in young adults, who have reached the peak of their developmental trajectory. [less ▲]

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See detailGeneric Helical Liquids: Theory & Applications
Rod, Alexia UL; Dolcetto, Giacomo UL; Rachel, Stephan et al

Poster (2016, August 23)

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See detailOn the Properties of Zenith Total Delay Time Series from Reprocessed GPS Solutions
Klos, Anna; Teferle, Felix Norman UL; Hunegnaw, Addisu UL et al

Poster (2016, July 29)

Global Positioning System observations from stations in regional and global networks have proven to sense the conditions of the atmosphere, especially the water vapour content of the troposphere. Zenith ... [more ▼]

Global Positioning System observations from stations in regional and global networks have proven to sense the conditions of the atmosphere, especially the water vapour content of the troposphere. Zenith Total Delay (ZTD) derived during the processing of GPS data is a measure of the total atmospheric delay along the signal path between satellite and receiver antennas and arises mostly from the hydrostatic and wet parts of the atmosphere. Having taken surface pressure and temperature into account, ZTD can be converted into an estimate of the Integrated Water Vapour (IWV) content of the atmosphere, which when derived from homogenously reprocessed GPS observations, is emerging as an important parameter in the monitoring of climate change. Especially, the long-term trend and variations in IWV together with their associated uncertainties are of high interest as atmospheric water vapour is the dominant greenhouse gas. To date the trend estimates and their uncertainties are widely determined with assumption that the stochastic properties of the time series follow a random, ie. white noise, process. However, if ZTD and IWV are directly linked to climate processes, one would expect that the underlying noise process has similar character to that found in other climate parameters, which have been modelled by means of an autoregressive process. If this proves to be true, the trend estimates and their uncertainties in ZTD and IWV may have been underestimated up to this day of an order of magnitude. In this research, we examine the properties of both deterministic and stochastic parameters of the ZTDs that were estimated by the consortium of the British Isles continuous GNSS Facility (BIGF) and the University of Luxembourg TIGA Analysis Centres (BLT) for GPS data collected by a global tracking network of more than 700 stations (repro2 solution). The analysis has been started with the homogenisation of the ZTD time series, which is an important task to provide homogeneity over the long-term. Here we used all previously reported discontinuities for a single station along with those added after manually inspecting the time series. This procedure did lead to a total number of 2505 discontinuities for this data set. Next, all significant oscillations were identified with spectral analysis and thereafter modelled with a Least-Squares Method. The residuals were subjected to noise analysis with different stochastic models. The results showed that an autoregressive model of fourth order combined with a white noise process is the optimal model for the ZTD time series. Finally, we provide an optimum evaluation of the ZTD trends and their uncertainties for selected climate zones, which were established according to the Köppen-Geiger climate classification. [less ▲]

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See detailFatherhood Desires and Intentions: A Comparison of Childless Gay and Straight Men in Germany
Kranz, Dirk; Busch, Holger; Niepel, Christoph UL

Poster (2016, July)

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See detailThe effect of a French intervention on children´s spelling of morphosyntactic agreement.
Bilici, Natalia UL; Ugen, Sonja UL; Weth, Constanze UL

Poster (2016, July)

The purpose of our project MorphoSyn is to gain insights into the morphosyntactic processing involved in spelling in second languages. We conduct our study in the complex language context of Luxembourg ... [more ▼]

The purpose of our project MorphoSyn is to gain insights into the morphosyntactic processing involved in spelling in second languages. We conduct our study in the complex language context of Luxembourg which has two written school languages (German and French) and a large variety languages spoken at children´s home. More specifically, we investigate how an explicit teaching of morphosyntactic structures in written German and French enhance the spelling competence of 5th grade students. During our intervention we focus on two orthographic features: the capitalisation of nouns in German and subject-verb agreement and the agreement within nouns phrases in French. Studies from Germany and France show that the acquisition of these features pass quite difficultly, because they are inaudible and, to grasp them, students need knowledge that goes beyond phoneme-grapheme correspondences. We predicted that our multilingual pupils will encounter the same problems that have been detected for French and German monolingual children. Our recently conducted pilot study confirmed this assumption: many children still omit plural/feminine markers in French and fail to capitalize abstract nouns or nominalisations in German. Our paper will present the outcome of the pre-test administrated to 250 Luxembourgish students (listening comprehension and dictation in German and French). It will show the orthographic skills pupils have acquired during primary school in their school languages German and French and indicate how far they are using morphosyntactic information while spelling. [less ▲]

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See detailAnnotating and Georeferencing of Digitized Early Maps
Höhn, Winfried UL; Schommer, Christoph UL

Poster (2016, July)

Original early maps are usually only accessible for a small group of researchers and librarians because they are very old and sensitive, and could be easily destroyed. However, they are a valuable ... [more ▼]

Original early maps are usually only accessible for a small group of researchers and librarians because they are very old and sensitive, and could be easily destroyed. However, they are a valuable knowledge source for historical research, because they are also political and cultural evidences of its time. In the age of Digital Humanities, online access and information search in digitized historical documents and early maps allows people from all over the world to work with such artefacts of cultural heritage. However, the digitization solely generates images of the artefacts without any access to the semantics of the documents. [less ▲]

Detailed reference viewed: 80 (12 UL)
See detailChemical stability of the Cu2SnS3/Mo interface
De Wild, Jessica UL; Robert, Erika UL; Dale, Phillip UL

Poster (2016, June)

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See detailDéveloppement d’un instrument de dépistage des précurseurs cognitifs pour l’apprentissage scolaire dans un contexte multilingue
Cornu, Véronique UL; Hornung, Caroline UL

Poster (2016, June)

Nombreuses études ont pu constater que les aptitudes et les apprentissages précoces influencent les apprentissages académiques ultérieurs. La valeur prédictive de différentes fonctions cognitives à l’âge ... [more ▼]

Nombreuses études ont pu constater que les aptitudes et les apprentissages précoces influencent les apprentissages académiques ultérieurs. La valeur prédictive de différentes fonctions cognitives à l’âge préscolaire est un sujet toujours vivement discuté. L'apprentissage des mathématiques, de la lecture et de l'écrit sont soutenues par des fonctions cognitives telles que les capacités pré-numériques, le langage, les fonctions visuo-spatiales, les fonctions exécutives dont la mémoire de travail, la vitesse de traitement et la raisonnement logique. Néanmoins, seulement peu de données scientifiques sont actuellement disponibles sur l’apport de ces différentes fonctions cognitives aux apprentissages scolaires dans un contexte multilingue comme celui du Luxembourg. Au Luxembourg environ 35 % des élèves scolarisés à l'école maternelle parlent Luxembourgeois à la maison. La plupart des enfants parlent d'autres langues voire plusieurs langues au sein de leur famille. A l'école maternelle les enfants apprennent le Luxembourgeois pendant 2-3 ans. Ensuite en 1ère année de l'enseignement fondamental primaire public, tous les enfants sont alphabétisés en Allemand. Et ce n'est qu'un an plus tard que le Français s'ajoute aux apprentissages scolaires. L'apprentissage des langues est un projet ambitieux au Luxembourg et les résultats nationaux ont montré que 42 % des élèves en 3e année primaire (CE2) n'ont malheureusement pas obtenu le niveau minimal à atteindre visé par le plan d'étude en 2013 (Hornung, Hoffmann, Lorphelin, Gamo, Ugen, Fischbach, & Martin, 2015). Le but est de développer un instrument qui s'adapte au contexte scolaire multilingue et qui permet de mesurer ces précurseurs cognitifs d’une manière valide. Ce projet vise à mieux comprendre comment différentes capacités cognitives précoces influencent les différents apprentissages scolaires dans un contexte scolaire multilingue chez l’enfant de 4 à 7 ans et les résultats de ce projet pourront servir comme base pour pouvoir développer des outils d’intervention visant à stimuler le développement de ces précurseurs dans un contexte multilingue. La présente batterie de tests inclut plusieurs épreuves brèves individuelles pour évaluer les performances numériques et visuo-spatiales, la capacité d'inhibition verbale et d'inhibition motrice, l'empan de la mémoire de travail verbale et visuo-spatiale, la flexibilité verbale, la vitesse de traitement, la conscience phonologique, la discrimination visuelle et le vocabulaire expressif chez l’enfant de 4 à 7 ans. Ces petites épreuves visent à évaluer ces différents précurseurs cognitifs de l’apprentissage scolaire et elles ont été développées et adaptées spécifiquement pour le contexte préscolaire suite à un pilotage avec la population cible. Dans une première phase, les relations entre ces différentes épreuves seront étudiées pour pouvoir concrétiser notre compréhension sur l’interrelation de ces différents précurseurs cognitifs. Afin de pouvoir évaluer la valeur prédictive de ces différentes fonctions cognitives, une approche longitudinale est visée. Nous avons prévu de mettre en relation les résultats obtenus au préscolaire (Phase I) avec les résultats de ces mêmes enfants obtenus lors des «épreuves standardisées» du monitoring scolaire au Luxembourg, réalisées en première année de l’école primaire (CP en France) (Phase II). [less ▲]

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See detailEarly life adversity associates with increased depressive symptoms and few active T cells in adulthood
Elwenspoek, Martha; Schaan, Violetta UL; Hengesch, Xenia et al

Poster (2016, June)

Detailed reference viewed: 85 (6 UL)
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See detailDifférences inter‐ et intraindividuelles en besoin de cognition
Keller, Ulrich UL; Strobel, Anja; Martin, Romain UL et al

Poster (2016, June)

Detailed reference viewed: 94 (9 UL)
Peer Reviewed
See detailInterventions addressing subjective well-being in ageing: Promissing approaches on individual and societal level
Boll, Thomas UL; Ferring, Dieter UL

Poster (2016, June)

Subjective well-being (SWB) in aging is important not only as an indicator of positive aging, but also because of its effects on relevant outcomes for the person (e.g., health) and the community (e.g ... [more ▼]

Subjective well-being (SWB) in aging is important not only as an indicator of positive aging, but also because of its effects on relevant outcomes for the person (e.g., health) and the community (e.g., involvements). This raises the question of how SWB of older people can be improved through interventions. Our contribution focusses on three domains for improving SWB: Optimization of resources (e.g., financial situation, autonomy), help with critical life events (e.g., widowhood, disablement), and support at the end of life. We consider reasons for optimizing SWB in these areas as well as the theoretical and empirical foundation for interventions. Among them are (1) bottom-up approaches regarding the link between domain-specific SWB (e.g., regarding health, financial situation, social relationships) and global SWB, (2) Coping approaches to critical life events frequently occuring in old age (e.g., widowhood, disablement) and (3) research on terminal decline of SWB. Against this background principal possibilities of optimizing SWB in these domains are delineated and both individual and societal (e.g., communal, national) level interventions are described. [less ▲]

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See detailA PRELIMINARY STUDY ON THE STABILITY OF PARTICLE LADEN JETS THROUGH A FULLY COUPLED CFD-DEM SOLVER
Peters, Bernhard UL; Pozzetti, Gabriele UL

Poster (2016, May 22)

Jets are widely used in engineering applications. In material machinery, hydro-transportation systems as well as in chemical industry it is common to deal with a dispersed solid phase interacting with the ... [more ▼]

Jets are widely used in engineering applications. In material machinery, hydro-transportation systems as well as in chemical industry it is common to deal with a dispersed solid phase interacting with the jet, and therefore creating a so-called slurry-jet or particle-laden jet. The stability of a jet is a key issue for many of these processes, still the underlying physics of this turbulent multiphase flow is highly complicated. Conventional CFD approaches have been proven satisfying for the study of the stability of two-phase jets. When a solid dispersed phase is present in the system, the stability problem gets more complicated and dependent on the solid phase dynamic. A possible solution for the problem is to extend the CFD solver capability through a correct coupling with a DEM solver. In this work a preliminary investigation on the potentialities of this kind of approach is presented and compared with a pure CFD approach. In particular the effect of the presence of differently sized particles in the jet is outlined and the influence of particle properties and concentration is investigated. Finally some considerations about the computational cost of different methods are proposed. The fluid phases are solved through an Eulerian finite volume (FV) multiphase solver based on the OpenFoam® libraries, and coupled with the XDEM code in order to treat the dispersed phase in a Lagrangian way. [less ▲]

Detailed reference viewed: 130 (18 UL)