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See detailConsolidating Observation of Land and Sea Level Changes around South Georgia Island
Teferle, Felix Norman UL; Hunegnaw, Addisu UL; Hibbert, Angela et al

Poster (2019, December 13)

With its mid-ocean location in the Southern Atlantic Ocean South Georgia Island is in a key position for the oceanic and geodetic global monitoring networks. Since 2013 the tide gauge at King Edward Point ... [more ▼]

With its mid-ocean location in the Southern Atlantic Ocean South Georgia Island is in a key position for the oceanic and geodetic global monitoring networks. Since 2013 the tide gauge at King Edward Point (KEP) with GLOSS ID 187 has been monitored using a GNSS station nearby on Brown Mountain. By accurately geo-referencing the tide gauge and monitoring any vertical land movements, a continuous record of its datum within the Permanent Service for Mean Sea Level (PSMSL) can be established, which in turn makes the recorded and averaged sea levels useful for long-term studies and satellite altimetry calibrations. In 2014 another GNSS station was installed at KEP after local subsidence was sus-pected and later on three additional GNSS stations came to service at the periphery of the main island, making it possible to monitor uplift/subsidence wider afield. Further-more, 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, i.e. the stability of the jetty upon which the tide gauge is mounted. In this study, we will present the results from the GNSS and precise levelling meas-urements, and will discuss their impact on the sea level record from the KEP tide gauge and nearby satellite altimetry sea surface heights. This study comes at a timely manner as during the Austral Summer 2019/2020 the jetty will be stabilized and en-larged, and consequently the current tide gauge will be replaced by a new one. Our measurements show that uplift is observed all over South Georgia Island while the ar-ea at KEP and particularly the jetty with tide gauge are subsiding relative to the rest of the island. In contrast, results for the tide gauge record show a lower magnitude of ob-served sea level rise than expected from nearby satellite altimetry. We will revisit all geodetic and oceanic observations in an attempt to improve the agreement between these measurements to summarize the status before the work at the jetty begins. [less ▲]

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See detailFrom tech to bench: Deep Learning pipeline for image segmentation of high-throughput high-content microscopy data
Garcia Santa Cruz, Beatriz UL; Jarazo, Javier UL; Saraiva, Claudia UL et al

Poster (2019, November 29)

Automation of biological image analysis is essential to boost biomedical research. The study of complex diseases such as neurodegenerative diseases calls for big amounts of data to build models towards ... [more ▼]

Automation of biological image analysis is essential to boost biomedical research. The study of complex diseases such as neurodegenerative diseases calls for big amounts of data to build models towards precision medicine. Such data acquisition is feasible in the context of high-throughput screening in which the quality of the results relays on the accuracy of image analysis. Although the state-of-the-art solutions for image segmentation employ deep learning approaches, the high cost of manual data curation is hampering the real use in current biomedical research laboratories. Here, we propose a pipeline that employs deep learning not only to conduct accurate segmentation but also to assist with the creation of high-quality datasets in a less time-consuming solution for the experts. Weakly-labelled datasets are becoming a common alternative as a starting point to develop real-world solutions. Traditional approaches based on classical multimedia signal processing were employed to generate a pipeline specifically optimized for the high-throughput screening images of iPSC fused with rosella biosensor. Such pipeline produced good segmentation results but with several inaccuracies. We employed the weakly-labelled masks produced in this pipeline to train a multiclass semantic segmentation CNN solution based on U-net architecture. Since a strong class imbalance was detected between the classes, we employed a class sensitive cost function: Dice coe!cient. Next, we evaluated the accuracy between the weakly-labelled data and the trained network segmentation using double-blind tests conducted by experts in cell biology with experience in this type of images; as well as traditional metrics to evaluate the quality of the segmentation using manually curated segmentations by cell biology experts. In all the evaluations the prediction of the neural network overcomes the weakly-labelled data quality segmentation. Another big handicap that complicates the use of deep learning solutions in wet lab environments is the lack of user-friendly tools for non-computational experts such as biologists. To complete our solution, we integrated the trained network on a GUI built on MATLAB environment with non-programming requirements for the user. This integration allows conducting semantic segmentation of microscopy images in a few seconds. In addition, thanks to the patch-based approach it can be employed in images with different sizes. Finally, the human-experts can correct the potential inaccuracies of the prediction in a simple interactive way which can be easily stored and employed to re-train the network to improve its accuracy. In conclusion, our solution focuses on two important bottlenecks to translate leading-edge technologies in computer vision to biomedical research: On one hand, the effortless obtention of high-quality datasets with expertise supervision taking advantage of the proven ability of our CNN solution to generalize from weakly-labelled inaccuracies. On the other hand, the ease of use provided by the GUI integration of our solution to both segment images and interact with the predicted output. Overall this approach looks promising for fast adaptability to new scenarios. [less ▲]

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See detailPOSTER: Traffic Splitting to Counter Website Fingerprinting
de La Cadena Ramos, Augusto Wladimir UL; Mitseva, Asya UL; Pennekamp, Jan et al

Poster (2019, November 11)

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See detailThe stability of academic self-concept profiles – a latent transition analysis
Franzen, Patrick UL; Arens, A. Katrin; Niepel, Christoph UL

Poster (2019, November 06)

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See detailDeep Learning Quality Control for High-Throughput High-Content Screening Microscopy Images
Garcia Santa Cruz, Beatriz UL; Jarazo, Javier UL; Schwamborn, Jens Christian UL et al

Poster (2019, October 10)

Automation of biological image analysis is essential to boost biomedical research. The study of complex diseases such as neurodegenerative diseases calls for big amounts of data to build models towards ... [more ▼]

Automation of biological image analysis is essential to boost biomedical research. The study of complex diseases such as neurodegenerative diseases calls for big amounts of data to build models towards precision medicine. Such data acquisition is feasible in the context of high-throughput high-content screening (HTHCS) in which the quality of the results relays on the accuracy of image analysis. Deep learning (DL) yields great performance in image analysis tasks especially with big amounts of data such as the produced in HTHCS contexts. Such DL and HTHCS strength is also their biggest weakness since DL solutions are highly sensitive to bad quality datasets. Hence, accurate Quality Control (QC) for microscopy HTHCS becomes an essential step to obtain reliable pipelines for HTHCS analysis. Usually, artifacts found on these platforms are the consequence of out-of-focus and undesirable density variations. The importance of accurate outlier detection becomes essential for both the training process of generic ML solutions (i.e. segmentation or classification) and the QC of the input data such solution will predict on. Moreover, during the QC of the input dataset, we aim not only to discard unsuitable images but to report the user on the quality of its dataset giving the user the choice to keep or discard the bad images. To build the QC solution we employed fluorescent microscopy images of rosella biosensor generated in the HTHCS platform. A total of 15 planes ranging from -6z to +7z steps to the two optimum planes. We evaluated 27 known focus measure operators and concluded that they have low sensitivity in noisy conditions. We propose a CNN solution which predicts the focus error based on the distance to the optimal plane, outperforming the evaluated focus operators. This QC allows for better results in cell segmentation models based on U-Net architecture as well as promising improvements in image classification tasks. [less ▲]

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See detailThe impact of resilience on perceived chronic stress in undergraduate psychology students
Lenz, Hannah; Steffgen, Georges UL

Poster (2019, September 26)

The purpose of this exploratory study was to analyze the relationship between academic stressors and chronic stress in undergraduate psychology students, and to identify whether resilience and/or social ... [more ▼]

The purpose of this exploratory study was to analyze the relationship between academic stressors and chronic stress in undergraduate psychology students, and to identify whether resilience and/or social support function as mediators amid this relationship. Students from the University of Luxembourg and the University of Trier (N = 152) were recruited to fill out an online questionnaire consisting of the Trier inventory of chronic stress (Schulz et al., 2004), the resilience scale (Leppert et al., 2008), the perceived social support scale (Kliem et al., 2015), and five dimensions of academic stressors (Herbst et al., 2016). Results show a positive correlation between academic stressors and chronic stress. Multiple regression analysis prove that neither gender, home university, additional occupation nor social support are significant predictors of chronic stress. Compared to academic stressors and resilience, which account for more than 56% of the variance of students’ experienced chronic stress. Furthermore, academic stressors and chronic stress are mediated by resilience but not by perceived social support. The implications of the findings are discussed in terms of their relevance for the development of intervention programs against chronic stress of undergraduate students. [less ▲]

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See detailPhysical activity of children and adolescents in Luxembourg during school, physical education and leisure time: An accelerometry-based study
Eckelt, Melanie UL; Bund, Andreas UL; Hutmacher, Djenna UL et al

Poster (2019, September 13)

Objectives: Due to its great importance for development and health, the physical activity (PA) of children has become a key issue in research over the last decade. Simultaneously, the measurement of PA ... [more ▼]

Objectives: Due to its great importance for development and health, the physical activity (PA) of children has become a key issue in research over the last decade. Simultaneously, the measurement of PA has been strongly improved through the development of user-friendly and reliably working accelerometer, which allow to track PA over several consecutive days in an objective way. Although the benefits of accelerometry are well documented also for children (e.g. Hager et al., 2015), especially cross-national studies such as the Health Behaviour in School-aged Children (HBSC) are still using questionnaires and are focused only on overall or leisure time PA. This study as part of the PALUX project (Physical Activity of Children and Youth in Luxembourg) aims to (1) measure children's daily PA patterns using up-to-date accelerometers while (2) differentiating between PA in school, physical education and leisure time. Methods: In total, 242 children and adolescents (134 girls and 108 boys) aged from 10-18 years from 9 different schools in Luxembourg wore the ActiGraph GT3X-BT- accelerometer at the hip for a period of seven consecutive days. Total time in moderate-to-vigorous PA (MVPA) was calculated using the cut-of points from Evenson et al. (2008). Time spent in school and physical education were determined based on timetables provided by the schools. Results: Mean overall MVPA of participants over seven consecutive days was 307.6 min, with 98.4 min (32 %) during school time and 190.7 min (62 %) during leisure time. Only 16.7 min (6 %) of the school time MVPA were performed in physical education. Boys had more overall MVPA than girls (367.9 vs. 258.9 min, t(240) = 6.76, p < .01) due to significant differences in all areas considered here (schooltime: t(215) = 6.26, p < .01; leisure time: t(215) = 6.18, p < .01; physical education: t(188) = 3.07, p < .01). Children spent 25.6 min of an average physical education class of 77 min in MVPA, which is 19.71 % and thus much less than the 50 % recommended by the U.S. Department for Health and Human Sciences. Only 0.5% of the participants (1.2% of the boys and 0% of the girls) achieved this value. Discussion: Overall, 25.6 % of the children and adolescents in Luxembourg met WHO's PA guideline of at least 60 min MVPA per day, which is in line with results from other European countries. According to our data, the achieved MVPA is mainly due to leisure time activities, whereas the potential of school and physical education in providing and promoting PA has apparently not been fully exploited yet. The consistency of these findings will be examined in a second survey in 2019 [less ▲]

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See detailInteroceptive accuracy in preschool - aged children: The Jumping Jack Paradigm (JJP)
Opdensteinen, K.; Schaan, L.; Pohl, A. et al

Poster (2019, September 11)

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See detailThe destruction of distraction? Neural mechanisms of reduced task-related analgesia with aging.
Rischer, Katharina Miriam UL; Dierolf, Angelika UL; Gonzalez-Roldan, Ana Maria et al

Poster (2019, September 06)

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See detailCommunication with father and mother differently impacts suicidal behaviour
Catunda, Carolina UL; van Duin, Claire UL; Heinz, Andreas UL et al

Poster (2019, September)

Background: Positive relationships with parents can reduce the risk of suicidal behaviour in adolescents. Previous research has indicated that adolescents who report poor communication with their parents ... [more ▼]

Background: Positive relationships with parents can reduce the risk of suicidal behaviour in adolescents. Previous research has indicated that adolescents who report poor communication with their parents are more likely to display suicidal behaviour. The aim of this study is to find out whether communication with the father or mother is equally important for suicidal behaviour. Methods: A total of 5595 students aged from 12 to 18 years old in secondary school participated in the 2014 HBSC Luxembourg survey. They responded to a questionnaire including, among others: 4 questions regarding sadness, suicide ideation, planning and attempt, and 2 questions about ease of communication with their father and mother. Findings: Adolescents who indicate poorer communication with their mother or father have higher odds for all suicidal behaviours. Poor communication with fathers has a bigger influence on the odds for sadness, whereas poor communication with mothers has a bigger influence on the odds for attempted suicide. Lastly, adolescents who don`t have or don`t see their mother or father are at increased risk for the suicidal behaviours, although the odds are not as high as for those indicating very difficult communication with their parent(s). Discussion: The Luxembourgish findings confirm the results of previous research and go further showing that, as a determinant, communication with mother differs from the communication with father. More studies should confirm these findings and include other variables, such as social support and stress, in order to see their relation with the communication with both parental figures and suicidal behaviours. [less ▲]

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See detailAssociations between perceived discrimination and life satisfaction: An ecological momentary assessment pilot study of adolescents
Stogianni, Maria UL; Murdock, Elke UL

Poster (2019, August 31)

Perceived discrimination is an important predictor of life satisfaction in ethnic minority groups (Villegas-Gold & Hyung Chol Yoo, 2014). Discriminatory practices are related to lower levels of subjective ... [more ▼]

Perceived discrimination is an important predictor of life satisfaction in ethnic minority groups (Villegas-Gold & Hyung Chol Yoo, 2014). Discriminatory practices are related to lower levels of subjective well-being and greater anxiety (Clark, Anderson, Clark, & Williams, 1999). The present study aims to extend these findings by assessing the affective consequences of perceived discrimination with the use of experience sampling methodology. We are interested in within person changes in subjective well-being that occur as a result of perceived discrimination. International high-school students (N = 30) attending at European school of Luxembourg were recruited to participate in an e-diary study for a period of 10 days. Participants were first and second generation immigrants (Mage = 14.63, SD = .62) from different European and non-European countries, growing up in multicultural Luxembourg. Perceptions of discrimination by peers and teachers were assessed with a self-report questionnaire daily after school. Our measures captured different experiences of discrimination including discrimination based on gender, social status, ethnic origin, and physical appearance. Each evening, participants completed the Brief Multidimensional Students’ Life Satisfaction Scales (BMSLSS), which assesses satisfaction with life in general and satisfaction in five domains that are considered important for adolescents: self, family, friends, living environment, and school context. The findings suggest that experiences of discrimination were associated with lower levels of subjective well-being. Participants were less satisfied with themselves, their relationships, and their school environment during the days they reported higher levels of discrimination experiences. With this pilot study using ecological momentary assessment, we develop a more dynamic understanding of the within-person variability of different facets of well-being among first and second generation adolescent immigrants and their discrimination experiences in different domains. [less ▲]

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See detailHow is parental activity related to children's physical activity behavior?
Hutmacher, Djenna UL; Eckelt, Melanie UL; Bund, Andreas UL et al

Poster (2019, July 18)

Objectives: Social support from parents is considered a primary influence of youth’ physical activity (PA; Beets, Cardinal & Alderman, 2010). However, the mechanisms of parental influence are still poorly ... [more ▼]

Objectives: Social support from parents is considered a primary influence of youth’ physical activity (PA; Beets, Cardinal & Alderman, 2010). However, the mechanisms of parental influence are still poorly understood. As the theory of planned behavior (TPB; Ajzen, 1985) is a well-supported theoretical framework to study youth’ engaging in PA, this study wants to investigate if an increased PA of the parents is enhancing the PA of their children and is related to different constructs of the TPB. Method: 264 students (52,6% females) from 11 to 21 years participated in the study. Via a digital questionnaire the students indicated if they are active at least 60 minutes a day, if their mother and father is physically active on a regular basis and if they are active together with their parents. Regarding the TPB, attitudes, subjective norms, perceived behavioral control and intentions towards PA were assessed (Hagger, Chatzisarantis, Culverhouse & Biddle, 2003). Results: A multivariate ANOVA revealed that children reported higher PA rates, more intense attitudes and higher subjective norms towards PA when the father was physically active and when being active together with their parents. However, the perceived behavioral control was higher when children indicated that their mother was physically active. Discussion: As expected, results suggest that the reported PA of parents are related to the self-reported PA of children, and furthermore to the different constructs of the TPB. Especially fathers seem to be an important role model regarding PA, attitudes and subjective norms toward PA. [less ▲]

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See detailFacial perception and implicit prejudice: An eye-tracking study
Stogianni, Maria UL; Murdock, Elke UL

Poster (2019, July 09)

Racial bias can affect the way of processing visual stimuli that are targets of prejudice. Different levels of prejudice and the type of prejudice (implicit vs. explicit) were related to automatic and ... [more ▼]

Racial bias can affect the way of processing visual stimuli that are targets of prejudice. Different levels of prejudice and the type of prejudice (implicit vs. explicit) were related to automatic and controlled processes of visual exploration (Hansen Rakhshan, Ho, & Pannasch, 2015). The proposed study aims to extend these findings by including pictures of individuals that belong to different racial and ethnic groups (White, Asian, Black, Latino) and vary in prototypical characteristics. Images of the Chicago Face Database will be presented in an online study. Eye movements will be recorded during the presentation of visual stimuli. We will examine differences in exploratory looking behavior among natives in a western European country and individuals with migratory background. [less ▲]

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See detailThe use of value-added models for the identification of schools that perform “against the odds”
Levy, Jessica UL; Brunner, Martin; Keller, Ulrich UL et al

Poster (2019, July)

Value-added (VA) modeling aims to quantify the effect of pedagogical actions on students’ achievement, independent of students’ backgrounds. VA modeling is primarily used for accountability and high ... [more ▼]

Value-added (VA) modeling aims to quantify the effect of pedagogical actions on students’ achievement, independent of students’ backgrounds. VA modeling is primarily used for accountability and high-stakes decisions. To date, there seems to be no consensus concerning the calculation of VA models. Our study aims to systematically analyze and compare different school VA models by using longitudinal large-scale data emerging from the Luxembourg School Monitoring Programme. Regarding the model covariates, first findings indicate the importance of language (i.e., language(s) spoken at home and prior language achievement) in VA models with either language or math achievement as a dependent variable, with the highest amount of explained variance in VA models for language. Concerning the congruence of different VA approaches, we found high correlations between school VA scores from the different models, but also high ranges between VA scores for single schools. We conclude that VA models should be used with caution and with awareness of the differences that may arise from methodological choices. Finally, we discuss the idea that VA models could be used for the identification of schools that perform “against the odds”, especially for those schools that have positive VA scores over several years. [less ▲]

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See detailMagnetic Guinier Law
Malyeyev, Artem UL; Michels, Andreas UL

Poster (2019, June)

We introduce the Guinier law for the case of magnetic SANS and provide an analysis of experimental data on a Nd-Fe-B-based nanocomposite and on a rare-earth-free MnBi permanent magnet. The robustness of ... [more ▼]

We introduce the Guinier law for the case of magnetic SANS and provide an analysis of experimental data on a Nd-Fe-B-based nanocomposite and on a rare-earth-free MnBi permanent magnet. The robustness of this novel approach is discussed and the quantities derived are analyzed in the framework of the existing research literature. [less ▲]

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See detailOlder adult’s mental health networks: first results of the ARPA ageing project regarding expectations and needs of health professionals
Tournier, Isabelle UL; Hanon, Cécile; Vasseur-Bacle, Simon et al

Poster (2019, May 25)

The European project “ARPA ageing” (co-funded by the Erasmus+ strategic partnerships programme) aims to improve the efficiency of mental health networks for older people. In order to have a better ... [more ▼]

The European project “ARPA ageing” (co-funded by the Erasmus+ strategic partnerships programme) aims to improve the efficiency of mental health networks for older people. In order to have a better knowledge of the perceived strengths and weakness of these networks, we investigated by a survey the needs and expectations of health professionals such as geriatrists, nurses or nursing assistants. A questionnaire of 24 items with an estimated duration of 20 minutes was published online from the 1 March 2018 to the 1 April 2018 in Belgium, France, and Luxembourg. Preliminary data concern 90 health professionals (main categories: 15.6% of nurses, 10% of psychologists, 7.8% of geriatricians and 7.8% of nursing assistants) in the domain of mental health and/or elder care. Notably due to the fact that not all participants already worked with health networks, levels of “no answer” varied between 24.4% to 33.3 according the questions. First results on the total sample reveal that health professionals globally perceived health networks as beneficial to a holistic care approach and care continuity (both 51.1%), and to care access (48.9%). These networks were estimated as beneficial to the increase of professional knowledge regarding older adults (38.9%) and mental health (34.4%), and to the improvement of professional skills (38.9%). Main reported difficulties working with these networks were the lack of information about these networks (56.7%) and the related health professions (50.1%), the lack of time and financial compensation (both 36.7%), and of coordinating tools (36.7%). This study is being extended to more participants and countries (i.e., Greece and Romania) in order to have a larger and more representative understanding of the European situation and cultural differences regarding mental health networks. This information will guide the next steps of the ARPA ageing project: the development of a European Internet platform and the production of guidelines to facilitate the implementation and monitoring of efficient mental health networks in Europe. [less ▲]

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See detailSubjective Reasons for Using versus not Using Assistive Technologies in Aging Population: A Meta-Synthesis of Qualitative Studies
Abrilahij, Afsaneh UL; Boll, Thomas UL

Poster (2019, May 24)

The number of older people with limitations of activities of daily living in developing countries is predicted to increase by a factor of four between 2015 and 2050. One possibility to overcome such ... [more ▼]

The number of older people with limitations of activities of daily living in developing countries is predicted to increase by a factor of four between 2015 and 2050. One possibility to overcome such limitations is to promote the use of assistive technologies (ATs) in the aging population. Despite evident benefits of ATs in this context, the use rate is still low. To find out why this is the case, we performed systematic literature searches in PsycINFO, MEDLINE, and Google Scholar databases about subjective reasons of older people for use and non-use of these devices. We then performed a meta-synthesis of the relevant studies in order to arrive at a comprehensive view of older people’s reasons for the use or non-use of ATs. Beliefs about ease to use and reliability of AT use as well as perceived suggestion by significant others to use ATs were important reasons for using them. Beliefs about insecurity, uselessness and other attributes of ATs as well as desires to avoid burden for others were major reasons for not using of ATs. We systematized the identified subjective reasons for using versus not using as referring to (1) situation of need and demand for an AT, (2) suggestion by significant others, (3) act of using, and (4) consequences of AT use. Most of the reasons were reasons for non-use such as beliefs about negative attributes of ATs, and the consequences of their use. In contrast, desires were only rarely mentioned as reasons for use or non-use of ATs. Comparing subjective reasons of our meta-synthesis with predictors in ATs use models, we found that only 5 out of 25 identified subjective reasons have already been considered in these models. Thus, these models appear not yet to be sufficiently comprehensive. We suggest integrating the identified subjective reasons from our meta-synthesis as additional predictors in a comprehensive AT use model with an improved predictive power. [less ▲]

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See detailMint Centrality: A Centrality Measure for the Bitcoin Transaction Graph
Fiz Pontiveros, Beltran UL; Steichen, Mathis UL; State, Radu UL

Poster (2019, May 17)

In this work, we consider the graph of confirmed transactions in Bitcoin. Understanding this graph is essential to discern the different economic activities conducted by the pseudonymous actors. In ... [more ▼]

In this work, we consider the graph of confirmed transactions in Bitcoin. Understanding this graph is essential to discern the different economic activities conducted by the pseudonymous actors. In addition to traditional graph analysis methods, new metrics need to be engineered specifically for the bitcoin transaction graph. Hence, we propose a new centrality measure named mint centrality. The measure uses the inherent tree structure of transactions in bitcoin and their relation to the corresponding set of coinbase transactions, and can be evaluated with linear complexity. We evaluate the mint centrality on the first 200,000 blocks of the public bitcoin blockchain. [less ▲]

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See detailAre dates processed like words rather than like numbers? A study of transposition priming effects
Lochy, Aliette UL; Golinvaux, Fanny; Schiltz, Christine UL

Poster (2019, May)

Neuropsychological case-studies suggested that dates and encyclopedic numbers may be processed differently than unknown numbers. However, this issue was not yet investigated in reading in healthy ... [more ▼]

Neuropsychological case-studies suggested that dates and encyclopedic numbers may be processed differently than unknown numbers. However, this issue was not yet investigated in reading in healthy participants, so that it is unclear if dates are read like words and processed as lexical items, or like numbers where each position strictly defines the digit value in a base-10 system. Here, we compared processing of known dates to unknown numbers in a group of 26 experts (students and teachers in History). Participants performed an explicit recognition task on dates (e.g., 1789, 1945, …) and on acronyms (e.g., FNRS, HDMI, …), half known and half unknown. They were preceded by an identical prime (e.g., 1945-1945), a transposed-character prime (e.g., 1495-1945) or a substituted-character prime (e.g., 1635-1945). Results show that for dates, there is a significant transposition gain (-57ms), while for unknown numbers as well as for acronyms (known and unknown), the transposed-character prime induced a cost (from +17 to +257ms) rather than a gain. The facilitation due to transposed characters found here on dates is similar to what is observed in studies of lexical decision on words. Therefore, it suggests that dates may be processed with similar types of orthographical mechanisms than words. [less ▲]

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See detailEmotion Regulation Difficulties in Adolescents with ADHD and/or Dyslexia
Battistutta, Layla UL; Steffgen, Georges UL

Poster (2019, April 26)

Objectives: ADHD is commonly associated with emotion regulation (ER) problems. Although around 10-45% of adolescents with ADHD also present with specific learning disorders such as dyslexia, studies on ER ... [more ▼]

Objectives: ADHD is commonly associated with emotion regulation (ER) problems. Although around 10-45% of adolescents with ADHD also present with specific learning disorders such as dyslexia, studies on ER in dyslexia or comorbid cases of ADHD/dyslexia remain limited. The aim was to examine potential differences in ER abilities between 11 to 16-year-old adolescents diagnosed with ADHD, dyslexia as well as comorbid dyslexia/ADHD. Method: Preliminary data from an ongoing research project was analyzed for 3 diagnostic groups (AD(H)D: n=15; dyslexia: n=12; dyslexia/AD(H)D: n=9) paired on age (F<1, n.s.), gender (X2(2)=0.68, p=.71) and IQ (F<1, n.s.). ER was investigated experimentally using a frustration inducing task (Behavioral Indicator of Resiliency to Distress; BIRD; Lejuez et al., 2006) while assessing adolescents’ subjective positive and negative affect before and after the task (PANAS-C; Laurent et al., 1999). Additionally, adolescents completed questionnaires on alexithymia (AQC, Rieffe, Oosterveld & Terwogt, 2006) and difficulties in ER (DERS-SF; Kaufman et al., 2016). Results: Preliminary findings showed a significant effect of time (F(1,33)=6.46, p=.02, n2=.16) with higher negative affect reported after the task and a marginal diagnostic group effect (F(2,33)=3.05, p=.06, n2=.16) showing marginally higher negative affect for the comorbid group compared to the dyslexia group (p=.06). Marginally significant group differences (F(2, 33)=3.21, p=.05, n2=.16) also showed higher alexithymia scores for the comorbid group compared to the dyslexia group (p=.06) but alexithymia and post-task negative affect were not found to be correlated (r=.25, p=.13). No differences in self-reported ER difficulties were found (F(2,33)=2.52, p=.10, n2=.13) between the three diagnostic groups. Conclusion: These preliminary findings indicate that, compared to a single diagnosis of dyslexia, a dyslexia/ADHD comorbidity might potentially entail less developed ER skills. The ongoing data collection (bigger sample, control group) will help to further elucidate these tentative results in the future. [less ▲]

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See detailImproved Monitoringand Tracking Hurricanes using GPS Atmospheric WaterVapour
Ejigu, Yohannes Getachew; Teferle, Felix Norman UL; klose, Anna et al

Poster (2019, April 09)

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See detailLaser beam joining of copper to aluminum sheet
Mathivanan, Karthik UL; Plapper, Peter UL

Poster (2019, April 04)

Dissimilar metal joining plays a very important role in the battery connections, especially copper and aluminum sheets. The existing literatures for laser research mostly focused on joining from the less ... [more ▼]

Dissimilar metal joining plays a very important role in the battery connections, especially copper and aluminum sheets. The existing literatures for laser research mostly focused on joining from the less reflective aluminum side to bond with copper. In the current research, we explore the joining process from copper side.Finally the optical emission of Cu-Al joint is presented with 394 nm peak as an indication to study the melting of Al. [less ▲]

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See detailThe role of executive functions in task-related analgesia
Rischer, Katharina Miriam UL; Gigl, Sandra; Dierolf, Angelika UL et al

Poster (2019, March)

Introduction: Recent research suggests that weaker executive functions may be linked to a higher risk of pain chronicity. However, little is known about how executive functions affect the modulation of ... [more ▼]

Introduction: Recent research suggests that weaker executive functions may be linked to a higher risk of pain chronicity. However, little is known about how executive functions affect the modulation of acute pain. The present study aimed to investigate the impact of inhibitory control on the success of cognitive distraction from pain. Methods: Participants completed a battery of cognitive tasks (Go/NoGo, Color Stroop, Eriksen Flanker), assessing their cognitive inhibition and selective attention abilities. Additionally, self-report measures of pain catastrophizing and fear of pain were administered. In a pain distraction paradigm, participants completed either a cognitively demanding working memory task (2-back task) or a visually matched easy control task (target response task) while receiving warm or painful thermal stimuli to their left forearm. Nociceptive stimulus intensity was individually calibrated for each participant. Moreover, to maintain a similar level of task difficulty across participants, task speed was continuously adapted based on the participant's performance in the previous trials. Following each trial, participants rated the perceived intensity and unpleasantness of the thermal stimuli on visual analogue scales. Results: As expected, preliminary results indicate that the 2-back task, but not the target response task, successfully distracted participants from thermal pain, manifesting in significantly lower intensity and unpleasantness ratings. Importantly, the magnitude of the distraction effect was negatively associated with the Flanker effect. Discussion: In line with previous research, engaging in a cognitively demanding task led to significantly lower pain intensity and unpleasantness ratings when compared to an easy control task. Moreover, results indicate that better interference control abilities may predict greater task-related analgesia. Taken together, the results of the present study suggest that it is crucial to assess executive functions to develop a better understanding of the mechanisms behind cognitive distraction from pain. [less ▲]

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See detailTowards Optimized Deployment of Electric Bus Systems Using Cooperative ITS
Laskaris, Georgios UL; Seredynski, Marcin; Viti, Francesco UL

Poster (2019, January)

In this paper we analyze the impact of using cooperative intelligent transportation systems (C-ITS) to manage electrical bus systems. A simulation-based study is presented where three control strategies ... [more ▼]

In this paper we analyze the impact of using cooperative intelligent transportation systems (C-ITS) to manage electrical bus systems. A simulation-based study is presented where three control strategies are used to regulate the operations of a line, namely bus holding, Green Light Optimal Dwell Time Adaptation (GLODTA) and Transit Signal Priority (TSP). The results show, using a realistic scenario of a major line in Luxembourg City, that buses are efficiently operated without necessarily providing additional priority to public transport, hence without negatively affecting the capacity of the private vehicles system. Benefits in terms of headway regulations, energy consumption and travel time variance reductions are quantified. [less ▲]

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See detailA Markov Chain Monte Carlo Approach for Estimating Daily Activity Patterns
Scheffer, Ariane Hélène Marie UL; Bandiera, Claudia; Cantelmo, Guido et al

Poster (2019, January)

Determining the purpose of trips brings is a fundamental information to evaluate travel demand during the day and to predict longer-term impacts on the population’s travel behavior. The concept of tours ... [more ▼]

Determining the purpose of trips brings is a fundamental information to evaluate travel demand during the day and to predict longer-term impacts on the population’s travel behavior. The concept of tours is the most suited to consider the value of a daily scheduling of individuals and travel interdependencies. However, the meticulous care required for both collecting data of high quality and interpret results of advanced demand models are frequently considered as major drawbacks. The objective of this study is to incorporate into a standard trip-based model some inherent concepts of activity-based models in order to enhance the representation of travel behavior. The main focus of this work is to infer, employing utility theory, the trip purpose of a population, at a zonal level. Making use of Markov Chain Monte Carlo, a set of parameters is estimated in order to retrieve tour-based primitives of the demand. The main advantage of this methodology is the low requirements in terms of data, as no individual information are used, and the good interpretation of the model. Estimated parameters of the priors set a utility-based probability function for departure time, which allows to have a dynamic overview of the demand. In order to account for the tour consistency of travel decisions, a duration constraint is added to the model. The proposed model is applied to the region of Luxembourg city and the results show the potential of the methodologies for dividing an observed demand based on the activity at destination. [less ▲]

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See detailLateralization for faces in prereaders depends on the perceptual processing level: An EEG Fast Periodic Visual Stimulation study
Lochy, Aliette UL; Schiltz, Christine UL; Rossion, Bruno

Poster (2019, January)

The developmental origin of human adults’ right hemispheric lateralization to face stimuli is unclear, in particular because young infants’ right hemispheric advantage in face perception is no longer ... [more ▼]

The developmental origin of human adults’ right hemispheric lateralization to face stimuli is unclear, in particular because young infants’ right hemispheric advantage in face perception is no longer present in preschool children, before written language acquisition. Here we used fast periodic visual stimulation (FPVS) with scalp electrophysiology to test 52 preschool children (5 years old) at two levels of face processing (i.e., faces vs. objects, or discrimination between individual faces). While the contrast between faces and nonface objects elicits strictly bilateral occipital responses in children, discrimination of faces on the basis of identity in the same children is associated with a strong right hemispheric lateralization over the occipito-temporal cortex. Inversion of the face stimuli does not modulate right lateralization but significantly decreases the discrimination response. Furthermore, there is no relationship between right hemispheric lateralization in individual face discrimination and preschool levels of letter recognition. These observations suggest that right lateralization for face perception is essentially driven by the necessity to process faces at the level of identity. Overall, they also challenge the view that the adult right hemispheric lateralization for face perception emerges late and slowly during childhood due to increased competition with left lateralized posterior network for reading. [less ▲]

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See detailMotivations & barriers of companies for shifting towards circularity
Hild, Paula UL

Poster (2019)

The research follows a qualitative research approach, including 16 exploratory and 50 semi-structured expert interviews with representatives from the building sector and automotive supply firms. The ... [more ▼]

The research follows a qualitative research approach, including 16 exploratory and 50 semi-structured expert interviews with representatives from the building sector and automotive supply firms. The preliminary results put forward the interdependence of the actors’ perception of what would mean a circular economy model for Luxembourg. They also reveal the firm’s specific role in this system. The decision of a business actor to implement a circular economy practice depends primarily on its return on investment, the general regulatory pressure and the maturity of the industry and the company. In general, the hindrance for circularity is not the absence of a technological or technical solution. Besides, the sophistication of the firm given its awareness for concepts like the circular economy, sustainable development, or sustainability shapes its vision for the future in this field actively. As a push for action, interviewees suggested a regulatory framework for circularity. [less ▲]

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See detailHerzschlag-evozierte Potenziale bei Bulimia nervosa
Lutz, Annika UL; Van Dyck, Zoé UL; Schulz, André UL et al

Poster (2019)

Die ursprüngliche Annahme, dass Essstörungspatient/innen unter einem umfassenden Defizit der interozeptiven Wahrnehmung leiden, wird inzwischen differenzierter betrachtet. Unterschiedliche Befunde ergeben ... [more ▼]

Die ursprüngliche Annahme, dass Essstörungspatient/innen unter einem umfassenden Defizit der interozeptiven Wahrnehmung leiden, wird inzwischen differenzierter betrachtet. Unterschiedliche Befunde ergeben sich je nach betrachtetem Organsystem (Herz, Magen), Verarbeitungsebene (neuronal, Selbstbericht) und Diagnose. Die bisherige Befundlage ist jedoch unübersichtlich und widersprüchlich. Für Bulimia nervosa (BN) wurde sowohl reduzierte, als auch unveränderte Herzschlagwahrnehmung berichtet. Mit dem vorliegenden Beitrag steuern wir weitere Ergebnisse zur Herzschlagwahrnehmung bei und ergänzen diese um einen physiologischen Indikator der kortikalen Verarbeitung kardio-afferenter Signale (Herzschlag-evozierte Potenziale, HEPs). Es wurden 22 Frauen mit akuter oder teilremittierter BN (BMI 23,94±3,61; Alter 31,86±11,20) und 22 gesunde Frauen untersucht (BMI 24,24±3,37; Alter 31,00±10,15). Die Stichproben wurden nach Alter und BMI parallelisiert. Die Teilnehmerinnen führten eine Herzschlagwahrnehmungsaufgabe nach Schandry durch, während ein 64-Kanal-EEG aufgezeichnet wurde. HEPs wurden als mittlere EEG-Amplitude von 455ms bis 595ms nach der R-Zacke berechnet. Die Ergebnisse zeigen keine signifikanten Gruppenunterschiede in Herzschlagwahrnehmung, HEPs und Herzrate. Dies bestätigt vorherige Befunde einer intakten Herzschlagwahrnehmung bei BN. Zusätzlich können wir von einer intakten kortikalen Verarbeitung kardio-afferenter Reize ausgehen. Die Wahrnehmung des Herzschlags ist insbesondere für die Verarbeitung und Regulation von Emotionen relevant. Auf Basis der vorliegenden und früheren Befunde ist davon auszugehen, dass defizitäre Emotionsregulation bei BN nicht auf veränderte Herzschlagwahrnehmung zurückzuführen ist. [less ▲]

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See detailMultipathing Traffic to Reduce Entry Node Exposure in Onion Routing
Pennekamp, Jan; Hiller, Jens; Reuter, Sebastian et al

Poster (2019)

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See detailPATH-29. POTENTIAL OF RAMAN SPECTROSCOPY IN ONCOLOGICAL NEUROSURGERY
Kleine Borgmann, Felix; Husch, Andreas UL; Slimani, Redouane et al

Poster (2019)

Raman spectroscopy (RS) has gained increasing interest for the analysis of biological tissues within the recent years. It is a label-free, non-destructive method providing insights in biochemical ... [more ▼]

Raman spectroscopy (RS) has gained increasing interest for the analysis of biological tissues within the recent years. It is a label-free, non-destructive method providing insights in biochemical properties of tumor cells. It is possible to compare RS signals with histological properties of identical tissue parts. Therefore, RS bears promising potentials in neurosurgical neurooncology. On one hand, it could potentially be used for both intraoperative tumor diagnostics and resection control. On the other hand, it could provide important knowledge on tumor biochemistry and used for a subclassification of tumors with a potential impact on personalized therapy approaches. Within our group, we analyzed over 3000 measurement points in different brain tumors ex vivo with a robotized RS system and correlated the spectral curves with histopathological results. We separated and subclassified the data by AI-based methods. Additionally, we compared the latter results with those of a handheld probe, which is potentially navigatable for in vivo, intraoperative applications. We could demonstrate, that it is possible to separate distinct tumor groups only based on RS signals, especially by using computer-based signal analysis. Furthermore, we could demonstrate the differences of the spectra of deep-frozen and formalin-fixed tissues versus non-fixed tissues. Based on our results, we will highlight the potentials of RS for intraoperative neurosurgical application in resection control for brain tumors, as well as we will focus on the potentials for brain tumor diagnostics based purely on this method or by using it as an adjunct. Those methods bear additional potentials in the field of personalized chemotherapy approaches. [less ▲]

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See detailOptimisation de la prise en charge médicale des patients sortant de prison au Luxembourg
Battista, Jorge; Stein, Romain; Baumann, Michèle UL

Poster (2019)

Le passage en prison peut être un gain de chance pour la santé de la population carcérale qui a généralement un faible accès au système de soins. L’élargissement de prison peut devenir une période de ... [more ▼]

Le passage en prison peut être un gain de chance pour la santé de la population carcérale qui a généralement un faible accès au système de soins. L’élargissement de prison peut devenir une période de vulnérabilité où ce gain potentiellement acquis s’annule si la transition vers la société civile n’est pas anticipée. L’objectif principal était l’identification et l’analyse des facteurs qui favorisent et s’opposent à une pratique de soins primaires chez les patients sortant du milieu carcéral au Luxembourg. L’objectif secondaire était l’élaboration de recommandations à l’égard des principaux résultats en s’appuyant sur une revue de la littérature. Méthodes : Une enquête qualitative à l’aide d’entretiens semi-dirigés a été menée auprès de médecins généralistes et de patients-détenus. Les questions des deux guides d’entretien étaient semblables afin que l’analyse permette une mise en miroir des résultats. Un recueil des caractéristiques sociodémographiques a également été effectué. A l’aide de la transcription des entretiens, une analyse de contenu thématique catégorielle de ces derniers a été réalisée au regard des objectifs. Sur base des verbatim, des items ont été formulés et regroupés en dimensions puis en thèmes. Résultats : Notre analyse a mis en lumière le manque de relais entre la prison et l’extérieur à chaque étape de la prise en charge médico-psycho-sociale du point de vue des soins et des aides proposées en prison jusqu’à l’élargissement. Des recommandations concernant des améliorations possibles ont pu être proposées, comme la création d’un réseau de médecins généralistes prenant le relais ainsi qu’une véritable coopération avec des organisations prenant en charge des toxicomanes. Conclusion : Des reformes concernant les soins en prison devraient être envisagées entre le système de l’élargissement, la création de relais socio-médicaux et des alternatives à l’incarcération, en analogie aux transitions clinics retrouvés aux États-Unis. [less ▲]

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See detailSuicide Prevention in Luxembourg: Using the HBSC Symptom Checklist as an Alternative Tool for Screening
Catunda, Carolina UL; van Duin, Claire UL; Heinz, Andreas UL et al

Poster (2018, December 07)

Introduction: Suicide is one of the leading causes of death of young people and as such, screening for suicidal ideation is a major public health concern. However, there is fear that exposure to suicide ... [more ▼]

Introduction: Suicide is one of the leading causes of death of young people and as such, screening for suicidal ideation is a major public health concern. However, there is fear that exposure to suicide-related content would encourage suicide attempt. This false idea is a great barrier to effectively screen. Hence, the need for tools without suicide content. Purpose: The goal of this study is to present a short tool that could be helpful for suicide screening and prevention. Materials and Methods: This study is based on the 2014 HBSC Luxembourg survey. A total of 5595 students aged from 12 to 18 years old in secondary school responded to a questionnaire translated to both French and German. Among others, it included the HBSC Symptom Checklist, a scale developed to measure eight health complaints (headache, abdominal pain, backache, feeling low, irritability, feeling nervous, sleeping difficulties and dizziness), as well as 4 questions asked in a logical sequence concerning sadness, suicide ideation, suicide planning and suicide attempt. Results: Multivariate Logistic Regression analyses with 24 potential indicators showed the number of health complaints as the most predictive indicator for suicide attempt (OR=1.248; C.I.: 1.175-1.325). Following, a significant ROC curve (area under the curve of 0.76; sensitivity=0.68 and specificity=0.73) and Youden Index (0.41) indicates the optimum cut-off at three complaints, with a predictive value of 17%. An alternative cut off point at four (sensitivity=0.57 and specificity=0.82; Youden Index of 0.39) has a predictive value of 21%. Conclusion: The HBSC Symptom Checklist seems to be a good predictor as each additional health complaint increases the risk of suicide attempt by 25%. In addition, it could be an alternative to traditional suicide screening measures, as its sensitivity, specificity and predictive values are similar to measures more commonly used, such as the Columbia Suicide Screen or the Beck Depression Inventory. Further work should be invested to validate the HBSC Symptom Checklist as a screening tool for suicide prevention. [less ▲]

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See detailSchulische Kompetenzen von Erstklässlern und ihre Entwicklung nach zwei Jahren.
Hoffmann, Danielle UL; Hornung, Caroline; Gamo, Sylvie UL et al

Poster (2018, November 08)

Jedes Jahr werden in den luxemburgischen Schulen die ÉpStan (Épreuves Standardisées) durchgeführt. Hierbei handelt es sich um nationale Schulleistungstests, welche Kompetenzen im Bereich der Mathematik ... [more ▼]

Jedes Jahr werden in den luxemburgischen Schulen die ÉpStan (Épreuves Standardisées) durchgeführt. Hierbei handelt es sich um nationale Schulleistungstests, welche Kompetenzen im Bereich der Mathematik und den Schulsprachen (Luxemburgisch, Deutsch und Französisch) auf standardisierte Art messen. Der vorliegende Beitrag ist sowohl eine Bestandsaufnahme der Schülerschaft zu Beginn des formalen Bildungswegs als auch ein Bericht ihrer Evolution über zwei Jahre im luxemburgischen Schulsystem. Hierzu haben wir die Daten aus drei Erhebungen (2014, 2015, 2016) der ÉpStan analysiert. Zum einen zeigen wir, anhand von Daten aus drei verschiedenen Kohorten, welche schulischen Kompetenzen Erstklässler (Zyklus 2.1) am Anfang ihrer Schullaufbahn aufweisen. Zudem hatten wir die Möglichkeit die Schüler und Schülerinnen der ersten Erhebung (2014) zwei Jahre später im Zyklus 3.1 nochmals zu testen und somit ihren Entwicklungsverlauf über zwei Jahre im luxemburgischen Bildungssystem zu dokumentieren. Diese ersten längsschnittlichen Daten zeigen, dass die Mehrheit der Schülerinnen und Schüler zu Beginn des Zyklus 2.1 das Niveau Avancé in den drei überprüften Kernkompetenzen („Luxemburgisch-Hörverstehen“, „Vorläuferfertigkeiten der Schriftsprache“ und „Mathematik“) erreicht. Somit stellen wir fest, dass die für den ersten Lernzyklus festgehaltenen Bildungsstandards erfüllt sind. Zwei Jahre später fällt die Verteilung der Schülerinnen und Schüler auf die verschiedenen Kompetenzränge negativer aus als im Zyklus 2.1. Im Zyklus 3.1 haben vergleichsweise mehr Kinder das Niveau Socle in allen drei Kernkompetenzen („Deutsch-Hörverstehen“, „Deutsch-Leseverstehen“ und „Mathematik“) noch nicht erreicht. Unsere Befunde zeigen außerdem, dass verschiedene außerschulische Faktoren (wie z. B. sozioökonomische Situation, Sprachhintergrund) bereits sehr früh im Verlauf der Schullaufbahn einen äußerst starken Einfluss auf die Testergebnisse haben und sich dieser Einfluss über die Jahre hinweg verstärkt. Abschließend präsentieren und diskutieren wir verschiedene Erklärungsansätze für diesen beobachteten Schereneffekt. [less ▲]

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See detailCognitive Potential and Academic Success in Luxembourg: Use case of the "Test of Cognitive Potential"
Muller, Claire UL; Reichel, Yanica UL; Wollschläger, Rachel UL et al

Poster (2018, November 08)

The “Test of Cognitive Ability” (“TCP”) is a language-free test of reasoning ability that was created at the heart of the Luxembourg Centre for Educational Testing (LUCET). The TCP was initially developed ... [more ▼]

The “Test of Cognitive Ability” (“TCP”) is a language-free test of reasoning ability that was created at the heart of the Luxembourg Centre for Educational Testing (LUCET). The TCP was initially developed for children at the age of 10 and can be applied in a group context. Since no advanced language-skills are required in order to take this test, it is perfectly suited not only to serve as a cognitive ability screener in a multi-lingual context, but also to study the relationship of cognitive ability and academic success within a demanding school-system that deals with a very complex mixture of student backgrounds (spoken languages, socioeconomic status, culture, etc.). Using traditional intelligence tests with language-based tasks and instructions could, in this context, result in biased data since maximum performance relies on a good understanding of task requirements. Being language-free, the TCP can help in gaining a more precise understanding of academic performance under different circumstances and prevent wrong conclusions as to the fairness of curricular requirements for different student populations. The present contribution will present the Test of Cognitive Potential and give an overview of how the relationship of cognitive ability and academic success varied within different subpopulations of a Luxembourgish sample of 303 4th graders. [less ▲]

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See detailSchool Shootings
Böhmer, Matthias UL; Hale, Miriam-Linnea UL

Poster (2018, November)

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See detailDEMO: An Effective Android Code Coverage Tool
Pilgun, Aleksandr UL; Gadyatskaya, Olga UL; Dashevskyi, Stanislav UL et al

Poster (2018, October 15)

The deluge of Android apps from third-party developers calls for sophisticated security testing and analysis techniques to inspect suspicious apps without accessing their source code. Code coverage is an ... [more ▼]

The deluge of Android apps from third-party developers calls for sophisticated security testing and analysis techniques to inspect suspicious apps without accessing their source code. Code coverage is an important metric used in these techniques to evaluate their effectiveness, and even as a fitness function to help achieving better results in evolutionary and fuzzy approaches. Yet, so far there are no reliable tools for measuring fine-grained bytecode coverage of Android apps. In this work we present ACVTool that instruments Android apps and measures the smali code coverage at the level of classes, methods, and instructions. Tool repository: https://github.com/pilgun/acvtool [less ▲]

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See detailoral history and technology - integrating digital tools in the scholarly workflow
Scagliola, Stefania UL; Corti, louise; Calamai, silvia et al

Poster (2018, October 08)

This poster is the outcome of the multidisciplinary workshop held in Munchen in september 2018, in which a multidisciplinary group of scholars experimented with automatic transcription tools, text ... [more ▼]

This poster is the outcome of the multidisciplinary workshop held in Munchen in september 2018, in which a multidisciplinary group of scholars experimented with automatic transcription tools, text analysis, annotation and emotion recognition tools, applied to interview data [less ▲]

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See detailCombining PET imaging and blood metabolomics data to improve machine learning models for Parkinson’s disease diagnosis
Glaab, Enrico UL; Trezzi, Jean-Pierre UL; Greuel et al

Poster (2018, October 08)

Objective: To investigate whether the integration of PET imaging and metabolomics data can provide improved machine learning models for PD diagnosis. Background: The reliable diagnosis of PD can remain ... [more ▼]

Objective: To investigate whether the integration of PET imaging and metabolomics data can provide improved machine learning models for PD diagnosis. Background: The reliable diagnosis of PD can remain challenging, even at the motor stage. PET imaging can be used to confirm the clinical diagnosis. However, limitations in the robustness of predictive features extracted from the data and the costs associated with PET imaging restrict its application. Using blood metabolomics data as an additional information source may provide improved combined diagnostic models and/or an initial filter to decide on whether to apply PET imaging. Methods: Metabolomics profiling of blood plasma samples using gas chromatography coupled to mass spectrometry (GC­MS) was conducted in 60 IPD patients and 15 healthy controls. After pre-processing, these data were compared to neuroimaging data for subsets of the same individuals using FDOPA PET (44 patients and 14 controls) and FDG PET (51 patients and 15 controls). Machine learning models using linear support vector machines were trained on 50% of the data and evaluated on a 50% hold­out test set using Receiver Operating Characteristic (ROC) curves. Next, standardized FDOPA and FDG PET intensity measurements were combined with those from the metabolomics data to build and evaluate sample classification models in the same manner as for the individual datasets. Results: Both for the FDOPA and FDG PET data, the predictive performance given by the area under the ROC curve (AUC) was highest when combining imaging features with those from the metabolomics data (AUC for FDOPA + metabolomics: 0.98; AUC for FDG + metabolomics: 0.91). The performance was generally lower when using only the respective PET attributes (FDOPA: 0.94, FDG: 0.8) or only the metabolomics data (AUC: 0.66). [less ▲]

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See detailThe Influence of Code Coverage Metrics on Automated Testing Efficiency in Android
Dashevskyi, Stanislav UL; Gadyatskaya, Olga UL; Pilgun, Aleksandr UL et al

Poster (2018, October)

Code coverage is an important metric that is used by automated Android testing and security analysis tools to guide the exploration of applications and to assess efficacy. Yet, there are many different ... [more ▼]

Code coverage is an important metric that is used by automated Android testing and security analysis tools to guide the exploration of applications and to assess efficacy. Yet, there are many different variants of this metric and there is no agreement within the Android community on which are the best to work with. In this paper, we report on our preliminary study using the state-of-the-art automated test design tool Sapienz. Our results suggest a viable hypothesis that combining different granularities of code coverage metrics can be beneficial for achieving better results in automated testing of Android applications. [less ▲]

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See detailFacilitating Privacy-preserving Recommendation-as-a-Service with Machine Learning
Wang, Jun UL; Arriaga, Afonso; Tang, Qiang et al

Poster (2018, October)

Machine-Learning-as-a-Service has become increasingly popular, with Recommendation-as-a-Service as one of the representative examples. In such services, providing privacy protection for users is an ... [more ▼]

Machine-Learning-as-a-Service has become increasingly popular, with Recommendation-as-a-Service as one of the representative examples. In such services, providing privacy protection for users is an important topic. Reviewing privacy-preserving solutions which were proposed in the past decade, privacy and machine learning are often seen as two competing goals at stake. Though improving cryptographic primitives (e.g., secure multi-party computation (SMC) or homomorphic encryption (HE)) or devising sophisticated secure protocols has made a remarkable achievement, but in conjunction with state-of-the-art recommender systems often yields far-from-practical solutions. We tackle this problem from the direction of machine learning. We aim to design crypto-friendly recommendation algorithms, thus to obtain efficient solutions by directly using existing cryptographic tools. In particular, we propose an HE-friendly recommender system, refer to as CryptoRec, which (1) decouples user features from latent feature space, avoiding training the recommendation model on encrypted data; (2) only relies on addition and multiplication operations, making the model straightforwardly compatible with HE schemes. The properties turn recommendation-computations into a simple matrix-multiplication operation. To further improve efficiency, we introduce a sparse-quantization-reuse method which reduces the recommendation-computation time by $9\times$ (compared to using CryptoRec directly), without compromising the accuracy. We demonstrate the efficiency and accuracy of CryptoRec on three real-world datasets. CryptoRec allows a server to estimate a user's preferences on thousands of items within a few seconds on a single PC, with the user's data homomorphically encrypted, while its prediction accuracy is still competitive with state-of-the-art recommender systems computing over clear data. Our solution enables Recommendation-as-a-Service on large datasets in a nearly real-time (seconds) level. [less ▲]

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See detailA Statistically Efficient Estimator for Co-array Based DoA Estimation
Sedighi, Saeid UL; Shankar, Bhavani UL; Ottersten, Björn UL

Poster (2018, October)

Co-array-based Direction of Arrival (DoA) estimation using Sparse linear arrays (SLAs) has recently gained considerable interest in array processing due to the attractive capability of providing enhanced ... [more ▼]

Co-array-based Direction of Arrival (DoA) estimation using Sparse linear arrays (SLAs) has recently gained considerable interest in array processing due to the attractive capability of providing enhanced degrees of freedom. Although a variety of estimators have been suggested in the literature for co-array-based DoA estimation, none of them are statistically efficient. This work introduces a novel Weighted Least Squares (WLS) estimator for the co-array-based DoA estimation employing the covariance fitting method. Then, an optimal weighting is given so that the asymptotic performance of the proposed WLS estimator coincides with the Cram\'{e}r-Rao Bound (CRB), thereby ensuring statistical efficiency of resulting WLS estimator. This implies that the proposed WLS estimator has significantly better performance compared to existing methods in the literature. Numerical simulations are provided to corroborate the asymptotic statistical efficiency and the improved performance of the proposed estimator. [less ▲]

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See detailThe Price of Privacy in Collaborative Learning
Pejo, Balazs UL; Tang, Qiang UL; Gergely, Biczok

Poster (2018, October)

Machine learning algorithms have reached mainstream status and are widely deployed in many applications. The accuracy of such algorithms depends significantly on the size of the underlying training ... [more ▼]

Machine learning algorithms have reached mainstream status and are widely deployed in many applications. The accuracy of such algorithms depends significantly on the size of the underlying training dataset; in reality a small or medium sized organization often does not have enough data to train a reasonably accurate model. For such organizations, a realistic solution is to train machine learning models based on a joint dataset (which is a union of the individual ones). Unfortunately, privacy concerns prevent them from straightforwardly doing so. While a number of privacy-preserving solutions exist for collaborating organizations to securely aggregate the parameters in the process of training the models, we are not aware of any work that provides a rational framework for the participants to precisely balance the privacy loss and accuracy gain in their collaboration. In this paper, we model the collaborative training process as a two-player game where each player aims to achieve higher accuracy while preserving the privacy of its own dataset. We introduce the notion of Price of Privacy, a novel approach for measuring the impact of privacy protection on the accuracy in the proposed framework. Furthermore, we develop a game-theoretical model for different player types, and then either find or prove the existence of a Nash Equilibrium with regard to the strength of privacy protection for each player. [less ▲]

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See detailWhy engage with Digital Source Criticism?
Garcia Martin, Cristina; Scagliola, Stefania UL

Poster (2018, September 26)

This poster illustrates the concept of the teaching platform Ranke.2 with lessons on Digital Source Criticism

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See detailVerlet buffer for broad phase interaction detection in Discrete Element Method
Mainassara Chekaraou, Abdoul Wahid UL; Rousset, Alban UL; Besseron, Xavier UL et al

Poster (2018, September 24)

The Extended Discrete Element Method (XDEM) is a novel and innovative numerical simulation technique that extends the dynamics of granular materials or particles as described through the classical ... [more ▼]

The Extended Discrete Element Method (XDEM) is a novel and innovative numerical simulation technique that extends the dynamics of granular materials or particles as described through the classical discrete element method (DEM) by additional properties such as the thermodynamic state, stress/strain for each particle. Such DEM simulations used by industries to set up their experimental processes are complexes and heavy in computation time. Therefore, simulations have to be precise, efficient and fast in order to be able to process hundreds of millions of particles. To tackle this issue, such DEM simulations are usually parallelized with MPI. One of the most expensive computation parts of a DEM simulation is the collision detection of particles. It is classically divided into two steps: the broad phase and the narrow phase. The broad phase uses simplified bounding volumes to perform an approximated but fast collision detection. It returns a list of particle pairs that could interact. The narrow phase is applied to the result of the broad phase and returns the exact list of colliding particles. The goal of this research is to apply a Verlet buffer method to (X)DEM simulations regardless of which broad phase algorithm is used. We rely on the fact that such DEM simulations are temporal coherent: the neighborhood only changes slightly from the last time-step to the current time-step. We use the Verlet buffer method to extend the list of pairs returned by the broad phase by stretching the particles bounding volume with an extension range. This allows re-using the result of the broad phase for several time-steps before an update is required once again and thereby its reduce the number of times the broad phase is executed. We have implemented a condition based on particles displacements to ensure the validity of the broad phase: a new one is executed to update the list of colliding particles only when necessary. This guarantees identical results because approximations introduced in the broad phase by our approach are corrected in the narrow phase which is executed at every time-steps anyway. We perform an extensive study to evaluate the influence of the Verlet extension range on the performance of the execution in terms of computation time and memory consumption. We consider different test-cases, partitioners (ORB, Zoltan, METIS, SCOTCH, ...), broad phase algorithms (Link cell, Sweep and prune, ...) and grid configurations (fine, coarse), sequential and parallel (up to 280 cores). While a larger Verlet buffer increases the cost of the broad phase and narrow phase, it also allows skipping a significant number of broad phase execution (> 99 \%). As a consequence, our first results show that this approach can speeds up the total .execution time up to a factor of 5 for sequential executions, and up to a factor of 3 parallel executions on 280 cores while maintaining a reasonable memory consumption. [less ▲]

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See detailAutogenous Laser welding of copper to aluminium
Mathivanan, Karthik UL; Plapper, Peter UL

Poster (2018, September 13)

This work investigates laser joining of copper sheets to aluminium in overlap configuration. Dissimilar Cu-Al connections are widely used in the electrical and electronics applications e.g. battery and ... [more ▼]

This work investigates laser joining of copper sheets to aluminium in overlap configuration. Dissimilar Cu-Al connections are widely used in the electrical and electronics applications e.g. battery and solar panels.Joining these materials is a very critical assembly process. The laser welding from the aluminium surface to copper (Al-Cu) is well described in the literature .But there is no data concerning the laser seam welding from the copper side to join with aluminium i.e Cu-Al.The selection of aluminium surface to irradiate is mainly because of poor absorption of copper to laser in IR region.But high intensities of about 100 MW/cm2 allow for initial vaporization of copper surface.Once the keyhole is generated, absorption of laser light is improved.Thereby high power lasers allow for successful penetration of copper surface to produce a joint with aluminium. The main objective is to investigate the approach of dissimilar laser welding starting from the copper surface to aluminium.The effect of process parameters on the shear force, microstructure and weld pool dimensions are studied.An experimental design is realized to see the effect of laser irradiation of copper surface (Cu-Al) in contrast to aluminium surface(Al-Cu). The selection of aluminium or copper surface is mainly dependent on the laser power.With the high power disk laser the possibility of joining from the copper side was evident and results of joining copper to aluminium and aluminium to copper are comparable.Therefore welding from a highly reflective surface to achive a comparable shear strength is demonstrated. [less ▲]

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See detailA multi-omic view of invasive genetic elements and their linked prokaryotic population dynamics within a mixed microbial community
Martinez Arbas, Susana UL; Narayanasamy, Shaman; Herold, Malte et al

Poster (2018, September 11)

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See detailLaser micro-welding of wire to flat geometry for dissimilar materials in an electromechanical application
Amne Elahi, Mahdi UL; Plapper, Peter UL

Poster (2018, September 11)

In the presented study, the laser welding of wire to flat geometry for miniature electromechanical hybrid components has been investigated. Laser welding offers variety of advantages compared to the ... [more ▼]

In the presented study, the laser welding of wire to flat geometry for miniature electromechanical hybrid components has been investigated. Laser welding offers variety of advantages compared to the current joining processes for this application however, considering the geometry of parts to be welded also mechanical properties requirement, an accurate spatial modulation of laser beam should be implemented to achieve a sound joint. Tensile shear test and optical microscopy were employed to represent the mechanical properties and melt pool geometry of the joint. All welds were done by power modulation of the laser beam to better control the energy input at several feed rates and three different beam trajectories. Results show that the shear load of the joint can be controlled by feed rate and the trajectory of the laser beam. The material combination of the study (Nickel and CuSn6), represents solubility in solid state therefore, by defining a proper spatial modulation of the laser beam a joint stronger than base wire metal is achievable. Figure 1 represents schematics of weld components. [less ▲]

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Peer Reviewed
See detailKnowledge Discovery Approach from Blockchain, Crypto-currencies, and Financial Stock Exchanges
Lagraa, Sofiane UL; Charlier, Jérémy Henri J. UL; State, Radu UL

Poster (2018, August 20)

Last few years have witnessed a steady growth in interest on crypto-currencies and blockchains. They are receiving considerable interest from industry and the research community, the most popular one ... [more ▼]

Last few years have witnessed a steady growth in interest on crypto-currencies and blockchains. They are receiving considerable interest from industry and the research community, the most popular one being Bitcoin. However, these crypto-currencies are so far relatively poorly analyzed and investigated. Recently, many solutions, mostly based on ad-hoc engineered solutions, are being developed to discover relevant analysis from crypto-currencies, but are not sufficient to understand behind crypto-currencies. In this paper, we provide a deep analysis of crypto-currencies by proposing a new knowledge discovery approach for each crypto-currency, across crypto-currencies, blockchains, and financial stocks. The novel approach is based on a conjoint use of data mining algorithms on imbalanced time series. It automatically reports co-variation dependency patterns of the time series. The experiments on the public crypto-currencies and financial stocks markets data also demonstrate the usefulness of the approach by discovering the different relationships across multiple time series sources and insights correlations behind crypto-currencies. [less ▲]

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See detailIntegrated time-resolved multi-omics for understanding microbial niche ecology
Herold, Malte UL; Narayanasamy, Shaman UL; Martinez Arbas, Susana UL et al

Poster (2018, August)

Microbial communities are strongly shaped by the niche breadths of their constituent populations. However, a detailed understanding of microbial niche ecology is typically lacking. Integrated multi-omic ... [more ▼]

Microbial communities are strongly shaped by the niche breadths of their constituent populations. However, a detailed understanding of microbial niche ecology is typically lacking. Integrated multi-omic analyses of host- or environment-derived samples offer the prospect of resolving fundamental and realised niches in situ. In turn, this is considered a prerequisite for niche engineering in order to drive an individual population or a community towards a specific phenotype, e.g., improvement of a biotechnological process. Here, we sampled floating islets on the surface of an activated sludge tank in a time-series spanning 51 time-points over 14 months. Multi-omics datasets (metagenomics, metatranscriptomics, metaproteomics, and (meta-)metabolomics) were generated for all time-points. Leveraging nucleotide sequencing data, we analyzed the community structure and reconstructed genomes for specific populations of interest. Moreover, based on their metabolic potential, three major groups emerged, serving as proxies for their respective fundamental niches . Time-resolved linkage of the proteomic and transcriptomic data to the reconstructed genomes revealed a fine-grained picture of niche realization. In particular, environmental factors (temperature, metabolites, oxygen) were significantly associated with gene expression of individual populations. Furthermore, we subjected the community to controlled oxygen conditions (stable or dynamic) in a bioreactor experiment and measured the transcriptomic response. Our results suggest short-term adaptations of populations of interest with respect to lipid metabolism, among other pathways. In conclusion, our work demonstrates how longitudinal multi-omic datasets can be integrated in order to further our understanding of microbial niche ecology within a biotechnological process with potential applications beyond waste water treatment. [less ▲]

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See detailInfluence of pubic symphysis stiffness on pelvis stress distribution during single leg stance
Ricci, Pierre-Louis UL; Maas, Stefan UL; Gerich, Torsten et al

Poster (2018, July 09)

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See detailAcculturation as a success story: Theoretical elaborations, lay perceptions and empirical evidence for “successful” migration in the multicultural context of Luxembourg
Albert, Isabelle UL; Barros Coimbra, Stephanie UL

Poster (2018, July 04)

Acculturation research has for a long time concentrated on problematic issues related to migration, often taking a deficit approach. Only recently have researchers shifted their focus toward factors that ... [more ▼]

Acculturation research has for a long time concentrated on problematic issues related to migration, often taking a deficit approach. Only recently have researchers shifted their focus toward factors that might be linked to positive outcomes of migration and integration. The present paper will deal with the question of how individuals from migrant and non-migrant families might profit from multiculturalism and cultural diversity in a resource-oriented perspective. After a theoretical elaboration on how “successful” migration could be defined and by which indicators it could be measured, we will focus on lay perceptions of this concept drawing on qualitative interviews from the FNR-funded IRMA study (“Intergenerational Relations in the light of Migration and Ageing”). More precisely, a number of altogether n = 20 Portuguese immigrant and Luxembourgish dyads of one parent and one adult child each discussed about their experiences and views on migration and the multicultural context of Luxembourg. Finally, we will identify predictors of subjective well-being in a quantitative sample of n = 73 Portuguese immigrant families (mostly one adult child together with both parents), taking into account satisfaction in different life domains as well as social and temporal comparison processes. Analyses show that for first generation immigrants as well as for their children social downward comparisons with Luxembourgish and Portuguese peers living in the host country were beneficial for their subjective well-being, whereas comparisons with Portuguese still living in Portugal and temporal comparisons were less important. The discussion will propose an integrative model for the study of migration taking into account participants’ generation status and their migration history. [less ▲]

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See detailCONSISTENT LEAST SQUARES ESTIMATOR FOR CO-ARRAY-BASED DOA ESTIMATION
Sedighi, Saeid UL; Shankar, Bhavani UL; Maleki, Sina et al

Poster (2018, July)

Sparse linear arrays (SLAs), such as nested and co-prime arrays, have the attractive capability of providing enhanced degrees of freedom by exploiting the co-array model. Accordingly, co-array-based ... [more ▼]

Sparse linear arrays (SLAs), such as nested and co-prime arrays, have the attractive capability of providing enhanced degrees of freedom by exploiting the co-array model. Accordingly, co-array-based Direction of Arrivals (DoAs) estimation has recently gained considerable interest in array processing. The literature has suggested applying MUSIC on an augmented sample covariance matrix for co-array-based DoAs estimation. In this paper, we propose a Least Squares (LS) estimator for co-array-based DoAs estimation employing the covariance fitting method as an alternative to MUSIC. We show that the proposed LS estimator provides consistent estimates of DoAs of identifiable sources for SLAs. Additionally, an analytical expression for the large sample performance of the proposed estimator is derived. Numerical results illustrate the finite sample behavior in relation to the derived analytical expression. Moreover, the performance of the proposed LS estimator is compared to the co-array-based MUSIC. [less ▲]

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See detailAssessing creativity
Gubenko, Alla UL; Houssemand, Claude UL

Poster (2018, July)

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See detailBlock Circulant Decomposition of Cross-Correlation Matrix for Transmit MIMO Beamforming
Hammes, Christian UL; Shankar, Bhavani UL; Ottersten, Björn UL

Poster (2018, July)

This paper deals with the design of transmit probing signal under the trade-off between good target discrimination (low cross-correlation beam pattern) and beam pattern design (desired auto-correlation ... [more ▼]

This paper deals with the design of transmit probing signal under the trade-off between good target discrimination (low cross-correlation beam pattern) and beam pattern design (desired auto-correlation beam pattern) in a Multiple-Input- Multiple-Output (MIMO) radar configuration. The quartic optimization problem, with a finite alphabet constraint on the probing signal and using Quadrature Phase Shift Keying (QPSK) in a multiplexed antenna system, is solved through a Fourier series approximation of the desired beam pattern by exploiting a block circulant property of the transmit signal matrix. The mean square error between an ideal and the proposed crosscorrelation beam pattern is -35 dB enhancing the attractiveness of the proposed approach. [less ▲]

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

Poster (2018, June 28)

Although numerical skills are essential in modern societies, 5- 7 % of the population suffer from mathematical learning disabilities. Due to the hierarchical nature of mathematical knowledge, screening ... [more ▼]

Although numerical skills are essential in modern societies, 5- 7 % of the population suffer from mathematical learning disabilities. Due to the hierarchical nature of mathematical knowledge, screening during the earliest stages of learning is essential to intervene efficiently. While different screening tools exist, they rely on verbal instructions and task content, hampering their usefulness in linguistically heterogeneous young school populations. We developed a computerized task that requires subjects to encode both auditory and visual numerical information to successfully respond to the task’s demands. For task instruction, participants were presented a video showing a person correctly solving three easy items of the task, before moving on to a practice session of three different items. If any item was solved incorrectly, the entire practice session was repeated for the participant. We administered the task to a sample of first grade students and collected participant’s performance in standardized addition, subtraction and number comparison (1 & 2-digit) tasks. A multivariate analysis with practice repetition as between-subject factor on the four standardized control measures revealed that participants that repeated the practice session scored significantly lower in three out of four dependent measures. These results suggest that the immediate understanding (i.e. practice items solved correctly on the first try) of our task, requiring deductive reasoning and an abstract, format-independent representation of quantity, is able to differentiate between high and low performers on standardized measures of basic math competence non-verbally at an early stage of learning. Implications and limitations will be discussed. [less ▲]

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See detailAn Offline Dictionary Attack Against zkPAKE Protocol
Lopez Becerra, José Miguel UL; Ryan, Peter UL; Sala, Petra UL et al

Poster (2018, June)

Password Authenticated Key Exchange (PAKE) allows a user to establish a strong cryptographic key with a server, using only knowledge of a pre-shared password. One of the basic security requirements of ... [more ▼]

Password Authenticated Key Exchange (PAKE) allows a user to establish a strong cryptographic key with a server, using only knowledge of a pre-shared password. One of the basic security requirements of PAKE is to prevent o ine dictionary attacks. In this paper, we revisit zkPAKE, an augmented PAKE that has been recently proposed by Mochetti, Resende, and Aranha (SBSeg 2015). Our work shows that the zkPAKE protocol is prone to o ine password guessing attack, even in the presence of an adversary that has only eavesdropping capabilities. Therefore, zkPAKE is insecure and should not be used as a password-authenticated key exchange mechanism [less ▲]

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See detailBuilding Bridges Across Heritage Silos
Kontiza, Kalliopi; Jones, Catherine UL; Padfield, Joseph et al

Poster (2018, June)

This research considers how best to cross the divides that exist between: (1) disparate practices between research fields (2) disparate interpretations of shared cultural heritage by the public and (3 ... [more ▼]

This research considers how best to cross the divides that exist between: (1) disparate practices between research fields (2) disparate interpretations of shared cultural heritage by the public and (3) disparate cultural heritage objects. [less ▲]

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See detailAutomatic discrimination of digits and letters in first graders and adults: an EEG Fast Periodic Visual Stimulation study.
Lochy, Aliette UL; Schiltz, Christine UL

Poster (2018, June)

Both letters and digits are arbitrary visual shapes that are distinguished into categories only after cultural acquisition. The observation that digits are easier to identify than letters has been ... [more ▼]

Both letters and digits are arbitrary visual shapes that are distinguished into categories only after cultural acquisition. The observation that digits are easier to identify than letters has been repeatedly reported in the literature (Shubert, 2017). In the present study, we used a Fast Periodic Visual Stimulation approach with EEG recordings to assess the automatic discrimination of letters and digits from each other in 1st grade children (N=17) and in adults (N=18). Participants viewed 40 sec sequences (3 repetitions per condition) of frequent stimuli (letters or digits) at a fast periodic rate (adults: 10Hz, children: 6Hz), in which rare stimuli (the other category of alphanumeric symbols) were periodically inserted (every five items, e.g., adults: at 2Hz, children: at 1.2Hz). Results showed discrimination responses in both groups in posterior occipito-temporal regions with clear changes in lateralization patterns. In children, stimuli contained only single elements. Responses were right-lateralized for digits among letters, and revealed a trend for left-lateralization for letters among digits. In adults, when stimuli contained only 1 character, both letters and digits gave rise to responses in the RH. However, when strings of characters were presented, then letters were discriminated from digits in the LH. These findings show a developmental pattern where single elements in children seem to be processed like strings of elements in adults. [less ▲]

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See detailIdentification patterns and subjective well-being in native and migrant emerging adults: The mediating role of self-efficacy
Stogianni, Maria UL; Murdock, Elke UL

Poster (2018, May 18)

Background: Luxembourg is one of the most diverse countries in Europe with a foreign population percentage of 47%. National identification processes become complex for young adults growing up in this ... [more ▼]

Background: Luxembourg is one of the most diverse countries in Europe with a foreign population percentage of 47%. National identification processes become complex for young adults growing up in this multicultural context with important implications for psychological outcomes. Research has shown that salience of national identification is heightened within this multicultural context (Murdock, Hirst, & Ferring, 2014) while higher levels of national identification are associated with life satisfaction and better health outcomes. Other findings suggest that intercultural contact can contribute to the development of a shared identity in highly diverse areas. The aim of this study was to investigate differences in identification patterns among native and non-native emerging adults and potential factors that mediate their impact on subjective well-being. As the native population is almost in the minority within its own country, we wanted to explore the relationships between well-being, ethnic, and transnational identification among this group. Methods: The sample included 260 young adults, ranging from 18 to 29 years old (M = 21.78, SD = 2.36). Participants were native citizens of Luxembourg and immigrants from different ethnic backgrounds. They completed standardized self-report questionnaires, including the Satisfaction with Life Scale and the General Self-Efficacy Scale. Identification with Luxembourg was assessed with the Multigroup Ethnic Identity Measure. Based on previous studies (van de Vijver et al, 2015), a 7-item scale was developed for the assessment of cosmopolitan/transnational identification, including items that assess beliefs about global citizenship and the level of contact with people from different ethnic groups. Results: All participants reported high levels of Luxembourgish and cosmopolitan identification with average scores M = 3.23 (SD = .79) and M = 4.15 (SD = .49) respectively. There were no significant differences for Luxembourgish identification and well-being between natives and non-natives but participants with migratory background scored significantly higher on the cosmopolitan identity scale. Luxembourgish and cosmopolitan identity correlated positively with self-efficacy in both groups and self-efficacy perceptions were positively related to well-being. To examine the direct and indirect relationships among these variables, we tested path mediation models with the two identity domains as predictors. The first model tested the mediating effect of self-efficacy on the relationship between identification patterns and well-being among native Luxembourgish citizens. The model showed a good fit χ²(1, N = 112) = .087, p = .768, RMSEA = .000, CFI = 1.00, indicating that ethnic identity was a significant predictor of self-efficacy perceptions which indeed mediated the effect of ethnic identification on well-being. Ethnic and transnational identification were not directly associated with the outcome variable. A second path model tested these relationships in the immigrant group χ²(1, N =145) = 2.452, p = .117, RMSEA = .100, CFI = .946. Neither identity component (Luxembourgish or cosmopolitan identity) was a significant predictor of subjective well-being but the findings suggest a mediating effect of self-efficacy on the relationship between transnational identification and well-being. Discussion: The present study contributes to the literature by exploring potential individual difference variables that affect the link between identification patterns and life satisfaction. [less ▲]

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See detailA Standardized Broker Model in Smart Cities
Liu, Chao UL; Varrette, Sébastien UL; Brust, Matthias R. UL et al

Poster (2018, May)

As urban residents are expected to represent more than 60 per cent of the world’s population by 2050, the current developments and interests in the “Smart City” concept are essential to enable the ... [more ▼]

As urban residents are expected to represent more than 60 per cent of the world’s population by 2050, the current developments and interests in the “Smart City” concept are essential to enable the successful transition to this new era. This paradigm relies on the integration of emerging Information and Communication Technologies (ICT), such as the Internet of Things (IoT), Cloud Computing, Big Data to manage assets and resources efficiently while facilitating the planning, construction, management and smart services within cities. While smart cities aim to enhance the quality, performance and interactivity of urban services at reduced cost, their realization is faced by many regulatory and technical challenges. Among these challenges, is the integration of renewable energy resources to the utility system of smart cities motivated by the increasingclimate change concerns. Adding further to its complexity, is the challenge of incorporating multiple renewable energy retailers in the same region each with their own pricing strategies due to the lack of a standardized metering indicator and billing system. These challenges create a need for an intelligent and standardized cloud-based energy broker to satisfying the end-user requests, and minimize expenses by efficiently selecting the most suitable energy retailer. In our work, a particular focus is raised towards the optimization of such energy brokering service which is motivated by the orchestration of a brokering role aiming to improve user experience and interaction with smart city services. Hence our main contribution is proposing a standardized intelligent broker model with smart trading strategies to cope with the dynamics and complexity of the energy retail market, while allocating energy resources based on endusers’ demands. This is achieved through the following steps: 1) studying a complete model of the broker service and involved parties within the exposed framework. 2) proposing a multiobjective heuristic to provide a dynamic optimization of the grid operations and resources, with full cyber-security, within the boundaries of the city. 3) analyzing the gaps among industry practices, market requirements and current technical standardization efforts at ISO/IEC JTC 1/ SC 38 (Cloud Computing and distributed platform) in order to pave the way to establishing standards in metering indicators and billing principles for cloud services this while keeping in mind privacy and data protection risks and regulations enforced by ISO JT1/SC 27 and EU General Data Protection Regulation effective May 2018. This research was conducted in collaboration with ILNAS - the Institut Luxem- bourgeois de la Normalisation, de l’Accréditation, de la Sécurité et qualité des produits et services (ILNAS) under the authority of the Minister of Economy, Luxembourg. [less ▲]

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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 detailOn Standardised UAV Localisation and Tracking Systems in Smart Cities
Samir Labib, Nader UL; Brust, Matthias R. UL; Danoy, Grégoire UL et al

Poster (2018, May)

In the near future, more than two thirds of the world’s population is expected to be living in cities and hence, with the aim of being proactive and finding innovative and sustainable solutions ... [more ▼]

In the near future, more than two thirds of the world’s population is expected to be living in cities and hence, with the aim of being proactive and finding innovative and sustainable solutions, governments have made smart cities one of their priority areas of research. Smart cities are sustainable, inclusive and prosperous greener cities that foster enabling smart Information and Communication Technologies (smart ICT) like Internet-of-Things (IoT), cloud computing and big data to facilitate services such as mobility, governance, utility and energy management. As these services depend heavily on data collected by sensors, Unmanned Aerial Vehicles (UAVs) have quickly become one of the promising IoT devices for smart cities thanks to their mobility, agility and customizability of onboard sensors. UAVs found use in a wide array of applications expanding beyond military to more commercial ones, ranging from monitoring, surveillance, mapping to parcel delivery and more demanding applications that require UAVs to operate in heterogeneous swarms in a shared low-altitude airspace over populated cities. However, as the number of UAVs continues to grow and as their sensing, actuation, communication and control capabilities become increasingly sophisticated, UAV deployment in smart cities is faced with a set of fundamental challenges in their safe operation and management. These challenges emphasize the need for establishing globally-harmonised regulations and internationally-agreed-upon technical standards to govern the rapid technological advancements, as well as ensure a fair economy by encouraging market competition and lowering barriers to entry for newcomers. As various Standardisation Development Organisations (SDOs) recently recognised the need, importance and potential of such regulations, most have established dedicated working groups addressing UAVs. However, most current SDO committees focus on aspects such as vehicle categorisation, specifications and operational procedures, but one usually overlooked elementary topic is UAV localisation. Due to its importance and close relation to other technical subsystems, the lack of a resilient, scalable and efficient standardised UAV localisation and tracking system is one of the main obstructing barriers hindering the integration and interoperability of UAV swarms in smart cities and hence impeding the realisation of their vast application benefits. In this work, we focus on studying the fundamental technical requirements, specifications and functions of such UAV localisation and tracking system, and explore its relationship to and importance in 1) optimising path planning, flight scheduling and utilising shared airspace, 2) collision avoidance and conflict resolution in highly populated residential areas and 3) addressing privacy and data protection concerns that could arise from UAV monitoring and surveillance applications. Furthermore, for each of the three aspects, we analyse current SDOs efforts such as those put forth by EASA, EUCARE WG73 and ISO TC20/SC16 on UAV systems, ISO JTC1/SC41 on IoT and related technologies and ISO JTC1/SC27, EU Directive 95/46 EC and GDPR on security, privacy and data protection, in order to identify and prioritise future research questions in relation to UAV localisation, aiming to make a contribution towards narrowing the gap between research and existing technical standards by encouraging multimode standardisation. This research was conducted in collaboration with ILNAS - the Institut Luxembourgeois de la Normalisation, de l’Accréditation, de la Sécurité et qualité des produits et services (ILNAS) under the authority of the Minister of Economy, Luxembourg. [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 ▲]

Detailed reference viewed: 101 (4 UL)
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: 228 (38 UL)
See detailA Trellis-Based SAT Problem
Franck, Christian UL

Poster (2018, April)

Detailed reference viewed: 40 (2 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: 68 (12 UL)
Full Text
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: 161 (24 UL)