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Peer Reviewed
See detailFair Assessment of Cognitive Abilities in Multilingual Children
Kijamet, Dzenita UL; Ugen, Sonja UL

Scientific Conference (2021, November 11)

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Peer Reviewed
See detailUsing Automatic Item Generation in the context of the Épreuves Standardisées (Épstan): A pilot study on effects of altering item characteristics and semantic embeddings
Michels, Michael Andreas UL; Hornung, Caroline UL; Inostroza Fernandez, Pamela Isabel UL et al

Scientific Conference (2021, November 11)

Assessing mathematical skills in national school monitoring programs such as the Luxembourgish Épreuves Standardisées (ÉpStan) creates a constant demand of developing high-quality items that is both ... [more ▼]

Assessing mathematical skills in national school monitoring programs such as the Luxembourgish Épreuves Standardisées (ÉpStan) creates a constant demand of developing high-quality items that is both expensive and time-consuming. One approach to provide high-quality items in a more efficient way is Automatic Item Generation (AIG, Gierl, 2013). Instead of creating single items, cognitive item models form the base for an algorithmic generation of a large number of new items with supposedly identical item characteristics. The stability of item characteristics is questionable, however, when different semantic embeddings are used to present the mathematical problems (Dewolf, Van Dooren, & Verschaffel, 2017, Hoogland, et al., 2018). Given culture-specific knowledge differences in students, it is not guaranteed that illustrations showing everyday activities do not differentially impact item difficulty (Martin, et al., 2012). Moreover, the prediction of empirical item difficulties based on theoretical rationales has proved to be difficult (Leighton & Gierl, 2011). This paper presents a first attempt to better understand the impact of (a) different semantic embeddings, and (b) problem-related variations on mathematics items in grades 1 (n = 2338), 3 (n = 3835) and 5 (n = 3377) within the context of ÉpStan. In total, 30 mathematical problems were presented in up to 4 different versions, either using different but equally plausible semantic contexts or altering the problem’s content characteristics. Preliminary results of IRT-scaling and DIF-analysis reveal substantial effects of both, the embedding, as well as the problem characteristics on general item difficulties as well as on subgroup level. Further results and implications for developing mathematic items, and specifically, for using AIG in the course of Épstan will be discussed. [less ▲]

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See detailFrontières et pluralité des marchés du travail : l’exemple du Luxembourg
Pigeron-Piroth, Isabelle UL; Belkacem, rachid

Scientific Conference (2021, November 11)

L’objet de cette communication est d’aborder la structuration des marchés transfrontaliers du travail. La situation du Luxembourg est particulièrement riche d’enseignements empiriques et théoriques. Dans ... [more ▼]

L’objet de cette communication est d’aborder la structuration des marchés transfrontaliers du travail. La situation du Luxembourg est particulièrement riche d’enseignements empiriques et théoriques. Dans ce petit pays au cœur de la Grande Région SaarLorLux, les frontières se vivent au quotidien. Le marché du travail est ouvert sur ses régions frontalières ainsi que sur l’espace mondial. Dans ce contexte, deux questions organisent notre problématique : Quels sont les effets des frontières sur la structuration du marché du travail ? Et quelles grilles de lectures théoriques paraissent les plus appropriées pour analyser cette structuration particulière du marché du travail ? [less ▲]

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See detailFuture living with AI and IA
Schommer, Christoph UL

Speeches/Talks (2021)

The present and the future will be determined by topics such as artificial intelligence and the question arises to what extent an often quoted usefulness, an "AI for Social Good" and "AI is for Humans ... [more ▼]

The present and the future will be determined by topics such as artificial intelligence and the question arises to what extent an often quoted usefulness, an "AI for Social Good" and "AI is for Humans" really applies. The lecture is intended to provide food for thought. [less ▲]

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See detailAnalogical Transfer despite Misleading Information in 2.5-5.5-year-olds
Bobrowicz, Katarzyna UL

Presentation (2021, November 11)

Analogical transfer is a pivotal skill early in life and has been repeatedly investigated by developmental psychologists. Recently, it was shown that already 2.5-year-olds are capable of such transfers ... [more ▼]

Analogical transfer is a pivotal skill early in life and has been repeatedly investigated by developmental psychologists. Recently, it was shown that already 2.5-year-olds are capable of such transfers, even with a 24-hour delay between two analogical situations [1; cf. 2, 3]. This ability, however, is poorly reflected in early curricula, failing to build upon early problem- solving flexibility. In this study, analogical transfer of relevant information despite irrelevant, distracting or misleading information is investigated in 2.5- to 5.5-year-olds. Children participate in a play session at day-care facilities and preschools, where they attempt to transfer relevant tool-use knowledge across two analogical problems despite a distracting or a misleading problem solved in between. Preliminary results suggest that 2.5-to-5.5-year-olds are capable of discarding both distracting and misleading information in analogical transfers. Further data collection should show whether this ability correlates with general intelligence, executive function, and bi-/multilingualism. [less ▲]

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See detailEnhancing Photovoltaic Hosting Capacity in Distribution Grid via Grid Reconfigurations, PV Droops and Battery Inverter Control
Torchyan, Khachatur UL

Doctoral thesis (2021)

The EU 2030 climate and energy framework has set a mandatory goal to achieve a renewable energy share in the final energy demand of 32% by 2030. Moreover, in the final National Energy and Climate Plan ... [more ▼]

The EU 2030 climate and energy framework has set a mandatory goal to achieve a renewable energy share in the final energy demand of 32% by 2030. Moreover, in the final National Energy and Climate Plan (NECP) Luxembourg has defined its renewable generation share goal at 25% by 2030. Between 2018 and 2019, three times more photovoltaic (PV) panels were installed than in the previous years. To achieve the NECP target and to ensure further smooth integration of PV systems, the PV hosting capacity (HC) of the grid should be enhanced. This thesis discusses the common issues and current developments of HC enhancement and presents three HC enhancement techniques: grid reconfiguration and grid-code modification, extended current droop control and transformer loading control. First, the thesis analyzes the potential of grid reconfiguration in HC enhancement. For the analysis the grid configurations are divided into meshed and radial subsets. The grid reconfiguration analysis and HC calculation are done using pandapower and NetworkX library. The cross-influence and the location of DG are considered while determining the HC of the grid. The analysis shows that proper grid configuration selection is important as it can substantially increase the HC and decrease the average loading in the lines. Second, the impact of extended current droops on HC enhancement is investigated. In the designed extended current droops (Id(V ), Iq(V )), extra reactive power reserve is made available by changing the droop gain of the reactive current droop when the overvoltage is not cleared by the existing reactive power reserve. The simulations proved that the extended current droops are a viable grid reinforcement strategy which can not only regulate the voltage at the point of common coupling (PCC), but also relax the transformer loading and improve overall voltage and frequency stability. Additionally, oversizing of the inverter increases the reactive power reserve, which in turn lowers the voltage profile and decreases the amount of curtailed active power. Finally, two novel communication-less transformer overloading protection strategies based on a battery energy storage (BES): transformer protection droops (TPD) and direct loading control (DLC), are designed and compared. Both strategies force the PV inverters to curtail their active power output without relying on communication. The strategies have been tested on detailed models, where the total installed PV power varies between 0.9 to 2 times the transformer rating. The static and dynamic performance of the DLC is superior to the TPD control strategy. DLC is a robust control strategy. It can reduce the transformer loading by 41%, compared to the grid configuration without BES and bring the system to the steady-state within 700ms in the worst-case scenario. It also ensures to keep the system voltages within safe operational limits. It can be used as a backup active power curtailment solution in the cases of communication failure in centralized control. [less ▲]

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See detailEffects of topological band structure on thermoelectric transport of bismuthene
Gaffar, Muhammad; Wella, Sasfan Arman; Hasdeo, Eddwi Hesky UL

in Physical Review. B (2021), 104(20), 205105

Two-dimensional bismuth (Bi) layer, known as bismuthene, exhibits Z2 topological bulk states due to large spin-orbit coupling that inverts the bands. Using the tight-binding method, we calculate the band ... [more ▼]

Two-dimensional bismuth (Bi) layer, known as bismuthene, exhibits Z2 topological bulk states due to large spin-orbit coupling that inverts the bands. Using the tight-binding method, we calculate the band structure of buckled bismuthene to understand its topological and trivial phases. We determine the thermoelectric properties for some considered phases, incorporating the edge states contribution, by using the linearized Boltzmann transport equation with a constant relaxation time approximation. It is shown that the thermoelectric figure of merit, ZT, actually drops in undoped topological bismuthene due to the edge effects. Surprisingly, the topological edge states enhance ZT at large doping with the Fermi energy near the bottom of bulk bands when bismuthene is nearly metallic. [less ▲]

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Peer Reviewed
See detailCentrality and city size effects on NO2 ground and tropospheric concentrations within European cities
Wei, Yufei UL; Caruso, Geoffrey UL; Lemoy, Rémi

Scientific Conference (2021, November 05)

Detailed reference viewed: 48 (4 UL)
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See detailЛюксембургские военнопленные в СССР и советские военнопленные в Люксембурге
Ganschow, Inna UL

Speeches/Talks (2021)

Presentation of a special course in which students of the Luxembourg and Tambov universities participate. Students of both countries are working on digitizing objects of war life, collecting information ... [more ▼]

Presentation of a special course in which students of the Luxembourg and Tambov universities participate. Students of both countries are working on digitizing objects of war life, collecting information at a microhistorical level, as well as immersing themselves in different aspects of war. [less ▲]

Detailed reference viewed: 39 (0 UL)
See detailIntroduction to Digital History
Zaagsma, Gerben UL

Presentation (2021, November 03)

Introduction to digital history for C²DH internal training program, focusing on the history of digital history and the ways in which digitised and digital heritage affects historical research (politics of ... [more ▼]

Introduction to digital history for C²DH internal training program, focusing on the history of digital history and the ways in which digitised and digital heritage affects historical research (politics of digitisation). [less ▲]

Detailed reference viewed: 68 (1 UL)
See detailWARCnet WG2 activities: a report
Schafer, Valerie UL

Scientific Conference (2021, November 03)

Detailed reference viewed: 24 (0 UL)
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Peer Reviewed
See detailCANMatch: A Fully Automated Tool for CAN Bus Reverse Engineering based on Frame Matching
Buscemi, Alessio UL; Turcanu, Ion; Castignani, German et al

in IEEE Transactions on Vehicular Technology (2021)

Controller Area Network (CAN) is the most frequently used in-vehicle communication system in the automotive industry today. The communication inside the CAN bus is typically encoded using proprietary ... [more ▼]

Controller Area Network (CAN) is the most frequently used in-vehicle communication system in the automotive industry today. The communication inside the CAN bus is typically encoded using proprietary formats in order to prevent easy access to the information exchanged on the bus. However, it is still possible to decode this information through reverse engineering, performed either manually or via automated tools. Existing automated CAN bus reverse engineering methods are still time-consuming and require some manual effort, i.e., to inject diagnostic messages in order to trigger specific responses. In this paper, we propose CANMatch a fully automated CAN bus reverse engineering framework that does not require any manual effort and significantly decreases the execution time by exploiting the reuse of CAN frames across different vehicle models. We evaluate the proposed solution on a dataset of CAN logs, or traces, related to 479 vehicles from 29 different automotive manufacturers, demonstrating its improved performance with respect to the state of the art. [less ▲]

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Peer Reviewed
See detailAutomatic Integration of Numerical Formats Examined with Frequency-tagged EEG
Marinova, Mila UL; Georges, Carrie UL; Guillaume, Mathieu et al

in Scientific Reports (2021)

How humans integrate and abstract numerical information across different formats is one of the most debated questions in human cognition. We addressed the neuronal signatures of the numerical integration ... [more ▼]

How humans integrate and abstract numerical information across different formats is one of the most debated questions in human cognition. We addressed the neuronal signatures of the numerical integration using an EEG technique tagged at the frequency of visual stimulation. In an oddball design, participants were stimulated with standard sequences of numbers (<5) depicted in single (digits, dots, number words) or mixed notation (dots – digits, number words – dots, digits – number words), presented at 10Hz. Periodically, a deviant stimulus (>5) was inserted at 1.25 Hz. We observed significant oddball amplitudes for all single notations, showing for the first time using this EEG technique, that the magnitude information is spontaneously and unintentionally abstracted, irrespectively of the numerical format. Significant amplitudes were also observed for digits – number words and number words – dots, but not for digits – dots, suggesting an automatic integration across some numerical formats. These results imply that direct and indirect neuro-cognitive links exist across the different numerical formats. [less ▲]

Detailed reference viewed: 27 (0 UL)
See detailMara's song
Aleksic, Gabrijela UL

Book published by Self-published (2021)

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the ... [more ▼]

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the nature and a refuge in music that she shares with her teacher and classmates in the end. [less ▲]

Detailed reference viewed: 26 (0 UL)
See detailMaras Lied
Aleksic, Gabrijela UL

Book published by Self-published (2021)

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the ... [more ▼]

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the nature and a refuge in music that she shares with her teacher and classmates in the end. [less ▲]

Detailed reference viewed: 29 (0 UL)
See detailLa chanson de Mara
Aleksic, Gabrijela UL

Book published by Self-published (2021)

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the ... [more ▼]

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the nature and a refuge in music that she shares with her teacher and classmates in the end. [less ▲]

Detailed reference viewed: 31 (0 UL)
See detailA Canção de Mara
Aleksic, Gabrijela UL

Book published by Self-published (2021)

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the ... [more ▼]

This book is a book I wrote for preschool immigrant children who struggle with learning a new language. Mara is a girl who comes to a new country and feels isolated in the school. She finds answers in the nature and a refuge in music that she shares with her teacher and classmates in the end. [less ▲]

Detailed reference viewed: 40 (0 UL)