Using Automatic Item Generation in the context of the Épreuves Standardisées (Épstan): A pilot study on effects of altering item characteristics and semantic embeddings

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 ▲]

Radial analysis and scaling of urban land use

in Scientific Reports (2021), (22044),

We determine the functional form and scaling law of radial artificial land use profiles in 300 European functional urban areas (FUAs). These profiles, starting from a fully artificial surface in the city ... [more ▼]

We determine the functional form and scaling law of radial artificial land use profiles in 300 European functional urban areas (FUAs). These profiles, starting from a fully artificial surface in the city center, decrease exponentially, the faster the smaller the city. More precisely, the characteristic decrease distance scales like the square root of total population, meaning that the artificial surface of cities is proportional to their population. This also means that the amount of artificial land per capita is independent of city size, and that larger cities are not more or less parsimonious in terms of land use than smaller ones. [less ▲]

Development of a screening tool for functional vision impairments in early childhood

Scientific Conference (2021, November 11)

Cerebral Visual Impairment (CVI) is a term used to designate a neurological disorder of the visual pathways impacting visual processes at any given level (Lueck et al., 2019). Due to the advances n ... [more ▼]

Cerebral Visual Impairment (CVI) is a term used to designate a neurological disorder of the visual pathways impacting visual processes at any given level (Lueck et al., 2019). Due to the advances n perinatal and medicinal care, CVI’s occurrence has increased significantly over the last years (Chokron & Dutton, 2016). The condition almost always entails aggregated functional vision impairments, i.e., limitations on the use of binocular vision during everyday tasks (Dutton, 2015). CVI can have effects on school achievements if undetected. Early detection is thus key to offer appropriate aids to avoid a negative impact on learning processes. The aim of this project is to develop a large-scale screener at the beginning of formal schooling, to identify functional vision impairments early on. For this reason, a set of items assessing different visual functions will be incorporated into the Luxembourgish school monitoring program. Based on a theoretical model of object recognition (Humphreys and Riddoch, 1987), we developed items that can be administered in a classroom setting which target different stages of visual perceptual processing, as well as visual functions connected with both dorsal and ventral streams, visual spatial processing and visual memory. We will present the design of the large-scale screener in relation to the theoretical model, as well as the rationale used to include or exclude various perceptual visual functions in the final test. Furthermore, we will explain the foreseen data collection and tool validation processes. [less ▲]

Enhancing Photovoltaic Hosting Capacity in Distribution Grid via Grid Reconfigurations, PV Droops and Battery Inverter Control

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 ▲]

Presenter: Childhood in Times of Political Transformation in the 20th Century

Presentation (2021, November 11)

What Tendency for "Inquiry" and "Language": Examining Key Journals in Science Education

Scientific Conference (2021, November 10)

Conducting a review of the literature can provide a foundation for understanding research trajectories in a given field, and this proposed presentation will explore one literature review mapping that has ... [more ▼]

Conducting a review of the literature can provide a foundation for understanding research trajectories in a given field, and this proposed presentation will explore one literature review mapping that has been conducted to guide a PhD research project relating primary science education and multilingual learning contexts. A first generic search with the terms “teacher education”, “primary education”, “science education”, “inquiry” and “language” led to an overwhelmingly high number of publications to be gathered and analyzed. So, the path of searching articles in the main scope of the research (science education) was chosen, towards the elaboration of an analytic review map. This mapping consists of a database that was built with articles retrieved from six key journals’ official website (identified through JCR/Scimago ranking), funneling the scope to “teacher education” in primary level (and elementary, for the USA context), and focusing on how the words “inquiry” and “language” emerge in these publications starting from 2008 (after the Rocard report, from 2007). This type of data is presented by the frequency of occurrences and analyzed by theme cluster for tendency construct, using content analysis. The first set of data extracted from one journal (CSSE) shows that “language” and “inquiry” appear in 35 documents, but the number of appearances in titles decreases to three occurrences, narrowed to two titles (one title overlaps both terms); serving as an example of an area to be potentially explored. In order to tackle how the implications and overlaps between language learning and science education (focusing on the inquiry-based method) are presented in published articles, the qualitative analysis exposes two set of results: 1. Occurrence and thematic mapping from a social-cultural perspective; 2. A set of meanings and its relevance to the topics as relations between the use of the words “inquiry” and “language” are drawn. [less ▲]

Martin Uhrmacher / Steve Kass / Sebastian Pauli : „Luxatlas.lu“, Methodik und Probleme bei der Erstellung eines digitalen und interaktiven historischen Stadtatlas – Werkstattbericht.

Scientific Conference (2021, November 09)

Gene-corrected p.A30P SNCA patient-derived isogenic neurons rescue neuronal branching and function

in Scientific Reports (2021), 11

Parkinson’s disease (PD) is characterised by the degeneration of A9 dopaminergic neurons and the pathological accumulation of alpha-synuclein. The p.A30P SNCA mutation generates the pathogenic form of the ... [more ▼]

Parkinson’s disease (PD) is characterised by the degeneration of A9 dopaminergic neurons and the pathological accumulation of alpha-synuclein. The p.A30P SNCA mutation generates the pathogenic form of the alpha-synuclein protein causing an autosomal-dominant form of PD. There are limited studies assessing pathogenic SNCA mutations in patient-derived isogenic cell models. Here we provide a functional assessment of dopaminergic neurons derived from a patient harbouring the p.A30P SNCA mutation. Using two clonal gene-corrected isogenic cell lines we identified image-based phenotypes showing impaired neuritic processes. The pathological neurons displayed impaired neuronal activity, reduced mitochondrial respiration, an energy deficit, vulnerability to rotenone, and transcriptional alterations in lipid metabolism. Our data describes for the first time the mutation-only effect of the p.A30P SNCA mutation on neuronal function, supporting the use of isogenic cell lines in identifying image-based pathological phenotypes that can serve as an entry point for future disease-modifying compound screenings and drug discovery strategies. [less ▲]

Effects of topological band structure on thermoelectric transport of bismuthene

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 ▲]

Google Scholar: a review of literature examining its effectiveness as a search tool

Learning material (2021)

Google Scholar (GS) is the top search engine used by those who are looking for scholarly content1. There are many reasons for this, not least that it feels familiar 2, 3. However, a review of the ... [more ▼]

Google Scholar (GS) is the top search engine used by those who are looking for scholarly content1. There are many reasons for this, not least that it feels familiar 2, 3. However, a review of the literature reveals that there are significant limitations to its effectiveness.   [less ▲]