References of "2021"
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See detailBrownian Loops, Layering Fields and Imaginary Gaussian Multiplicative Chaos
Camia, Federico; Gandolfi, Alberto; Peccati, Giovanni UL et al

in Communications in Mathematical Physics (2021), In press

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See detailA quasicontinuum approach towards mechanical simulations of periodic lattice structures
Chen, Li UL

Doctoral thesis (2021)

Thanks to the advancement of additive manufacturing, periodic metallic lattice structures are gaining more and more attention. A major attraction of them is that their design can be tailored to specific ... [more ▼]

Thanks to the advancement of additive manufacturing, periodic metallic lattice structures are gaining more and more attention. A major attraction of them is that their design can be tailored to specific applications by changing the basic repetitive pattern of the lattice, called the unit cell. This may involve the selection of optimal strut diameters and orientations, as well as the connectivity and strut lengths. Numerical simulation plays a vital role in understanding the mechanical behavior of metallic lattices and it enables the optimization of design parameters. However, conventional numerical modeling strategies in which each strut is represented by one or more beam finite elements yield prohibitively time­consuming simulations for metallic lattices in engineering­scale applications. The reasons are that millions of struts are involved, as well as that geometrical and material nonlinearities at the strut level need to be incorporated. The aim of this thesis is the development of multi­scale quasicontinuum (QC) frameworks to substantially reduce the simulation time of nonlinear mechanical models of metallic lattices. For this purpose, this thesis generalizes the QC method by a multi­field interpolation enabling amongst others the representation of varying diameters in the struts’ axial directions (as a consequence of the manufacturing process). The efficiency is further increased by a new adaptive scheme that automatically adjusts the model reduction whilst controlling the (elastic or elastoplastic) model’s accuracy. The capabilities of the proposed methodology are demonstrated using numerical examples, such as indentation tests and scratch tests, in which the lattice is modeled using geometrically nonlinear elastic and elastoplastic beam finite elements. They show that the multi­scale framework combines a high accuracy with substantial model reduction that are out of reach of direct numerical simulations. [less ▲]

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See detailThe Impact of the COVID-19 Pandemic on the Luxembourgish Education System: Differences between students based on background characteristics in elementary and secondary school
Fischbach, Antoine UL; Colling, Joanne UL; Levy, Jessica UL et al

Scientific Conference (2021, November)

Policy responses to the COVID-19 pandemic (e.g., school closure, home-schooling) have affected students at various stages of education all over the world and were found to increase inequalities in ... [more ▼]

Policy responses to the COVID-19 pandemic (e.g., school closure, home-schooling) have affected students at various stages of education all over the world and were found to increase inequalities in academic achievement (OECD, 2021). The present study is based on fully representative large-scale data from the Luxembourg School Monitoring Programme (Épreuves Standardisées; ÉpStan; LUCET, 2021). The ÉpStan are assessing key competencies of primary and secondary school students in different subjects (e.g., German, French and Math). To allow a fair performance comparison, socio-economic and socio-cultural backgrounds of students (e.g., gender, migration and language background) are systematically taken into consideration. The ÉpStan 2020 entail data from approximatively 25.000 students from five different grades (elementary and secondary school), from 15.000 parents (elementary school) and comparative data from 160.000 students from previous cohorts, thus providing key empirical findings on the pandemic’s impact on the Luxembourgish education system. In the present contribution, we analyze a) how the results of standardized achievement tests compare to previous cohorts and under consideration of students’ socio-economical and socio-cultural background, as well as b) how parents and students perceived home-schooling with regard to aspects such as coping, technical equipment, motivation or contact to teachers. First results indicate that in Grades 1, 5, 7 and 9, standardized achievement scores were generally stable in comparison to previous years. However, in Grade 3, students’ competency scores in German (primary language of instruction in elementary school) listening comprehension worsened substantially. Furthermore, third graders from socio-economically disadvantaged households and/or students that do not speak Luxembourgish/German at home did worse in German reading comprehension than their peers from socio-economically advantaged households and/or speaking Luxembourgish/German at home. Concerning the perception of home-schooling, students coped rather well with the situation, with German being a bit more challenging in primary school and math in secondary school. Findings concerning motivation and enjoyment of home-schooling were mixed, with primary school students’ motivation being comparably to the regular school setting but approximately half of the secondary school students being less motivated than in the regular school setting. Furthermore, all households seem to have been well equipped, with the situation being slightly more favorable in socio-economically advantaged households. For the majority of students, the contact with teachers was frequent, with teachers having adapted their type of support to the needs of their students (e.g., more personal contact towards students from socio-economically disadvantaged households). To conclude, it can be said that no systematic negative trend has been identified in students’ achievement scores. Only German listening comprehension in Grade 3 has worsened substantially and these skills should therefore be fostered as early as possible. Overall, students coped rather well with home-schooling without, however, particularly enjoying it. While students entering the pandemic with favorable background characteristics (e.g., higher socio-economic status, speaking a language of instruction at home) managed better both regarding competencies and perception of home-schooling, students with less favorable background characteristics have received more differentiated support. These findings underline that already existing inequalities in the Luxembourgish school system have in parts been intensified by the pandemic. References LUCET. (2021). Épreuves Standardisées (ÉpStan). https://epstan.lu OECD. (2021). The State of School Education: One Year into the COVID Pandemic. OECD Publishing. https://doi.org/10.1787/201dde84-en [less ▲]

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See detailEvasion Attack STeganography: Turning Vulnerability Of Machine Learning ToAdversarial Attacks Into A Real-world Application
Ghamizi, Salah UL; Cordy, Maxime UL; Papadakis, Mike UL et al

in Proceedings of International Conference on Computer Vision 2021 (2021)

Evasion Attacks have been commonly seen as a weakness of Deep Neural Networks. In this paper, we flip the paradigm and envision this vulnerability as a useful application. We propose EAST, a new ... [more ▼]

Evasion Attacks have been commonly seen as a weakness of Deep Neural Networks. In this paper, we flip the paradigm and envision this vulnerability as a useful application. We propose EAST, a new steganography and watermarking technique based on multi-label targeted evasion attacks. Our results confirm that our embedding is elusive; it not only passes unnoticed by humans, steganalysis methods, and machine-learning detectors. In addition, our embedding is resilient to soft and aggressive image tampering (87% recovery rate under jpeg compression). EAST outperforms existing deep-learning-based steganography approaches with images that are 70% denser and 73% more robust and supports multiple datasets and architectures. [less ▲]

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See detailUncovering Digital History’s forgotten roots: the work of the Association for History and Computing
Zaagsma, Gerben UL

Presentation (2021, October)

This talk has two parts. It will first attempt to frame what a history of digital history might look like, by focusing on hybridity as a key characteristic of historical research, seen as some form of ... [more ▼]

This talk has two parts. It will first attempt to frame what a history of digital history might look like, by focusing on hybridity as a key characteristic of historical research, seen as some form of integrating newly emerging tools, technologies, materials, and/or practices in historical research, and mapped and qualified according to the main phases of historical research. My main argument here is that, in order to ground our current ‘digital’ practices and learn from past experiences and expertise, we need an answer to the question: what were, and are, the continuities and ruptures in the use and uptake of new technologies in historical research, and in the debates that accompanied them? The paper will then proceed to outline what groundwork is necessary to explore digital history’s forgotten roots: a basic overview of the field’s different spatio-temporal trajectories and the networks of computing historians in the pre-PC and early PC period. A key focal point for such a reconstruction are the DH conferences that took place in the 1960s and 1970s, either as singular events or strands of bigger conferences such as the International Congress of Historical Sciences in Moscow in 1970, and later those that were organised under the aegis of the Association for History and Computing (AHC, 1987-2001) and its national member organisations. By studying which scholars attended and where they came from, and by linking that to the topics and methods that were discussed, it will be possible to chart, over time, shifting geographical, topical and methodological developments. In the second part of my paper, I will provide the first results of a concrete case study which is part of this broader endeavour, namely a web archaeology of the old AHC website and H-NET Discussion List for History and Computing (now: H-Digital History). [less ▲]

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See detailLocal Forms of Morphisms of Colored Supermanifolds
Covolo, Tiffany; Kwok, Stephen; Poncin, Norbert UL

in Journal of Geometry and Physics (2021), 168

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See detailIs the Z2xZ2-graded sine-Gordon equation integrable?
Bruce, Andrew UL

in Nuclear Physics B (2021), 971

We examine the question of the integrability of the recently defined Z2xZ2-graded sine-Gordon model, which is a natural generalisation of the supersymmetric sine-Gordon equation. We do this via ... [more ▼]

We examine the question of the integrability of the recently defined Z2xZ2-graded sine-Gordon model, which is a natural generalisation of the supersymmetric sine-Gordon equation. We do this via appropriate auto-Bäcklund transformations, construction of conserved spinor-valued currents and a pair of infinite sets of conservation laws. [less ▲]

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See detail"Just for the sake of transparency": Exploring Voter Mental Models Of Verifiability
Zollinger, Marie-Laure UL; Estaji, Ehsan UL; Ryan, Peter Y A UL et al

in Electronic Voting, Sixth International Joint Conference, E-Vote-ID 2021, Bregenz, Austria, October 5-8 (2021, October)

Verifiable voting schemes allow voters to verify their individual votes and the election outcome. The voting protocol Selene offers verification of plaintext votes while preserving privacy. Misconceptions ... [more ▼]

Verifiable voting schemes allow voters to verify their individual votes and the election outcome. The voting protocol Selene offers verification of plaintext votes while preserving privacy. Misconceptions of verification mechanisms might result in voters mistrust of the system or abstaining from using it. In this paper, we interviewed 24 participants and invited them to illustrate their mental models of Selene. The drawings demonstrated different levels of sophistication and four mental models: 1) technology understanding, 2) meaning of the verification phase, 3) security concerns, and 4) unnecessary steps. We highlight the misconceptions expressed regarding Internet voting technologies and the system design. Based on our findings, we conclude with recommendations for future implementations of Selene as well as for the design of Internet voting systems in general. [less ▲]

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See detailDeep Learning to Predict the Feasibility of Priority-Based Ethernet Network Configurations
Mai, Tieu Long UL; Navet, Nicolas UL

in ACM Transactions on Cyber-Physical Systems (2021), 5(4), 126

Machine learning has been recently applied in real-time systems to predict whether Ethernet network configurations are feasible in terms of meeting deadline constraints without executing conventional ... [more ▼]

Machine learning has been recently applied in real-time systems to predict whether Ethernet network configurations are feasible in terms of meeting deadline constraints without executing conventional schedulability analysis. However, the existing prediction techniques require domain expertise to choose the relevant input features and do not perform consistently when topologies or traffic patterns differ significantly from the ones in the training data. To overcome these problems, we propose a Graph Neural Network (GNN) prediction model that synthesizes relevant features directly from the raw data. This deep learning model possesses the ability to exploit relations among flows, links, and queues in switched Ethernet networks, and generalizes to unseen topologies and traffic patterns. We also explore the use of ensembles of GNNs and show that it enhances the robustness of the predictions. An evaluation on heterogeneous testing sets comprising realistic automotive networks, shows that ensembles of 32 GNN models features a prediction accuracy ranging from 79.3% to 90% for Ethernet networks using priorities as the Quality-of-Service mechanism. The use of ensemble models provides a speedup factor ranging from 77 to 1715 compared to schedulability analysis, which allows a far more extensive design space exploration. [less ▲]

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See detailExploring the History of Digital History
Zaagsma, Gerben UL

Scientific Conference (2021, September 20)

As long as new preservation technologies and computing machines have been developed, the question of their utility and uptake in historical research practices has been debated. Yet, the very fact that ... [more ▼]

As long as new preservation technologies and computing machines have been developed, the question of their utility and uptake in historical research practices has been debated. Yet, the very fact that historical knowledge production has always been affected by new and emerging technologies is often forgotten. Similarly, the fact that key epistemological and methodological questions in what we now call ‘digital history’ were already debated decades ago by earlier generations of computing historians (analog and digital) is often overlooked. There is a lack of transmission of accumulated knowledge from the past and it sometimes seems as if every new generation of historians rediscovers the promise of ‘digital history’, with all of its attending hopes, visions and ambitions for reinventing and reshaping historical research. To fill this gap, this paper will explore what a history of digital history might look like. It will do so by focusing on hybridity as a key characteristic of historical research. Hybridity, seen as some form of integrating newly emerging tools, technologies, materials, and/or practices in historical research, has a long history that predates the advent of computers. In my paper I will map and qualify that history according to the main phases of historical research. The paper will conclude by outlining what groundwork is necessary to explore digital history’s forgotten roots: a basic overview of the field’s different spatio-temporal and ideological trajectories and recreation of the networks of computing historians in the pre-PC and early PC period. [less ▲]

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See detailMachine learning in mix design of Miscanthus lightweight concrete
Pereira Dias, Patrick; Jayasinghe, Laddu Bhagya; Waldmann, Daniele UL

in Construction and Building Materials (2021)

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See detailBinary blended cement pastes and concrete using gravel wash mud (GWM) powders
Thapa, Vishojit; Waldmann, Daniele UL

in Construction and Building Materials (2021)

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See detailNonlinear three-dimensional anisotropic material model for failure analysis of timber
Eslami, Hooman; Jayasinghe, Laddu Bhagya; Waldmann, Daniele UL

in Engineering Failure Analysis (2021)

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See detailReview of Adam Crymble: Technology and the Historian. Transformations in the Digital Age
Zaagsma, Gerben UL

in H-Soz-Kult: Kommunikation und Fachinformation für die Geschichtswissenschaften (2021)

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See detailWeb Archives of the COVID Crisis: Digital Voices, Preservation and Loss
Schafer, Valerie UL

Presentation (2021, September 16)

This roundtable, which is organized by the WARCnet network and chaired by Valérie Schafer (C2DH, University of Luxembourg), aims to shed light on the issues, challenges, values and limits of web archiving ... [more ▼]

This roundtable, which is organized by the WARCnet network and chaired by Valérie Schafer (C2DH, University of Luxembourg), aims to shed light on the issues, challenges, values and limits of web archiving during the COVID crisis. It will combine analysis by web archivists and scholars and entwine analysis of web archiving practices and preserved web content, in order to address several key issues related to the conference, such as the “silences” and “noises” of these archives. The first part of the roundtable will focus on web archives collections that have been created during the COVID-19 crisis by many institutions throughout Europe. Friedel Geeraert (The State Archives of Belgium and the Royal Library of Belgium) will provide a short comparative overview of the strategies of web archiving institutions in Europe, that the team documented through an oral history campaign, while Nicola Bingham (The British Library, UK) will offer more precise overviews of the collections that were gathered respectively by the UK Web Archive and the IIPC (International Internet Preservation Consortium). Claude Mussou (Ina THEQUE, France) will explore the archiving of Twitter at the Institut national de l’audiovisuel (France). Niels Brügger (Aarhus University, Denmark) and Jane Winters (SAS, University of London) will then discuss memories and heritage of the COVID-crisis through the lens of these web archives. Finally the last part will focus on research approaches, notably close and distant reading, and the collective and individual traces, social and political expressions at stake in these web archives: Valérie Schafer will comment on the distant reading approach within these archives. Sophie Gebeil (Aix-Marseille University, France) will underline issues related to “carers” and social struggles. Valérie Schafer will also briefly mention the gendered approach of the COVID crisis that the working group is currently conducting. This roundtable will be followed by a discussion with the audience in order to deepen the topics that are at the core of the conference, whether it be loss, preservation, the political “we”, feelings, etc. [less ▲]

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See detailFacets of conscientiousness and their relation to academic achievement: a person-centered approach
Franzen, Patrick UL; Niepel, Christoph UL; Arens, A Katrin et al

Scientific Conference (2021, September 16)

Detailed reference viewed: 24 (0 UL)