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See detailPassé au féminin dans la littérature africaine. Penser l’auctorialité, retrouver ses racines
Barthelmebs-Raguin, Hélène UL

in Kuhnle, Till R.; Bauer, Lydia (Eds.) Forcer le monde à venir au monde ». Le renouvellement de la représentation de l’Afrique à travers la littérature (in press)

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See detailA Natural Experiment on Job Insecurity and Fertility in France
Clark, Andrew UL; Lepinteur, Anthony UL

in Review of Economics and Statistics (in press)

Job insecurity can have wide-ranging consequences outside of the labour market. We here argue that it reduces fertility amongst the employed. The 1999 rise in the French Delalande tax, paid by large ... [more ▼]

Job insecurity can have wide-ranging consequences outside of the labour market. We here argue that it reduces fertility amongst the employed. The 1999 rise in the French Delalande tax, paid by large private firms when they laid off workers aged over 50, produced an exogenous rise in job insecurity for younger workers in these firms. A difference-in-differences analysis of French ECHP data reveals that this greater job insecurity for these under-50s significantly reduced their probability of having a new child by 3.7 percentage points (with a 95% confidence interval between 0.7 and 6.6 percentage points). Reduced fertility is only found at the intensive margin: job insecurity reduces family size but not the probability of parenthood itself. Our results also suggest negative selection into parenthood, as this fertility effect does not appear for low-income and less-educated workers. [less ▲]

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See detailStudent Response Systems in Remote Teaching
Botev, Jean UL; Grevisse, Christian UL; Rothkugel, Steffen UL

in Proceedings of the 23rd International Conference on Human-Computer Interaction (HCI International) (in press)

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See detailIncome and Wealth Volatility: Evidence from Italy and the U.S. in the Past Two Decades
Menta, Giorgia UL; Wolff, Edward; d'ambrosio, Conchita UL

in Journal of Economic Inequality (in press)

Income volatility and wealth volatility are central objects of investigation for the literature on income and wealth inequality and dynamics. Here we analyse the two concepts in a comparative perspective ... [more ▼]

Income volatility and wealth volatility are central objects of investigation for the literature on income and wealth inequality and dynamics. Here we analyse the two concepts in a comparative perspective for the same individuals in Italy and the U.S. over the last two decades. We find that in both countries wealth volatility reaches significantly higher values than income volatility, the effect being mostly driven by changes in the market value of real estate assets. We also show that there is more volatility in both dimensions in the U.S. and that the overall trend in both countries is increasing over time. We conclude by exploring volatility in consumption. [less ▲]

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See detailCan Offline Testing of Deep Neural Networks Replace Their Online Testing?
Ul Haq, Fitash UL; Shin, Donghwan UL; Nejati, Shiva UL et al

in Empirical Software Engineering (in press)

We distinguish two general modes of testing for Deep Neural Networks (DNNs): Offline testing where DNNs are tested as individual units based on test datasets obtained without involving the DNNs under test ... [more ▼]

We distinguish two general modes of testing for Deep Neural Networks (DNNs): Offline testing where DNNs are tested as individual units based on test datasets obtained without involving the DNNs under test, and online testing where DNNs are embedded into a specific application environment and tested in a closed-loop mode in interaction with the application environment. Typically, DNNs are subjected to both types of testing during their development life cycle where offline testing is applied immediately after DNN training and online testing follows after offline testing and once a DNN is deployed within a specific application environment. In this paper, we study the relationship between offline and online testing. Our goal is to determine how offline testing and online testing differ or complement one another and if offline testing results can be used to help reduce the cost of online testing? Though these questions are generally relevant to all autonomous systems, we study them in the context of automated driving systems where, as study subjects, we use DNNs automating end-to-end controls of steering functions of self-driving vehicles. Our results show that offline testing is less effective than online testing as many safety violations identified by online testing could not be identified by offline testing, while large prediction errors generated by offline testing always led to severe safety violations detectable by online testing. Further, we cannot exploit offline testing results to reduce the cost of online testing in practice since we are not able to identify specific situations where offline testing could be as accurate as online testing in identifying safety requirement violations. [less ▲]

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See detailDe la naissance de l’État luxembourgeois. Analyse et historique de la problématique
Heuschling, Luc UL

in Actes de la Section des sciences morales et politiques, Institut grand-ducal (in press)

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See detailEuropean Embeddedness and the Founding of Luxembourg’s 21st Century Research University
Braband, Gangolf; Powell, Justin J W UL

in European Journal of Higher Education (in press)

At the heart of Western Europe and culturally embedded in “The Greater Region,” Luxembourg for centuries developed higher education (HE) primarily via international student mobility, not its own national ... [more ▼]

At the heart of Western Europe and culturally embedded in “The Greater Region,” Luxembourg for centuries developed higher education (HE) primarily via international student mobility, not its own national university. Evolving provisions of tertiary education after WWII followed construction of several teaching and research institutes that did not offer full-fledged higher education certification. The critical juncture—the founding of the national flagship University of Luxembourg (uni.lu)—occurred in 2003, since leading to an extraordinary case of university institutional¬ization. Traditions were explicitly maintained, but reshaped, in the new university, with student mobility continuing to bolster the national elite’s pan-European networks and internationalization. Reflecting its hyper-diversity, its multilingual culture, and its porous national borders, Luxembourg’s investments in higher education capacity-building have been thoroughly European. Today, Luxembourg has the highest proportion of HE graduates and of internationally mobile students, testament to its outgoing mobility tradition and national policy change facilitated by Europeanization. [less ▲]

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See detailSelf-Efficacy in Habit Building: How General and Habit-Specific Self-Efficacy Influ-ence Behavioral Automatization and Motivational Interference
Stojanovic, Marco; Grund, Axel UL; Fries, Stefan

in Frontiers in Psychology (in press)

In this paper, we investigate the role of self-efficacy in intentional habit building. We analyzed event sampling data from a habit building app we created that helps define and track habit data. We used ... [more ▼]

In this paper, we investigate the role of self-efficacy in intentional habit building. We analyzed event sampling data from a habit building app we created that helps define and track habit data. We used hierarchical growth curve modeling and multilevel mediation to test our hypotheses. In a first study, N = 91 university students built new study habits over a period of 6 weeks in a controlled study. We found that the trait-like (Level 2) general self-efficacy (GSE) predicted automaticity (i.e. habit strength) but not the experience of motivational interference (MI). In a second study with real user data, N = 265 idiographic habits have been analyzed. The specific self-efficacy associated with these habits - habit-specific self-efficacy (Level 1, HSE) - was measured during habit formation. We found that lagged HSE predicted automaticity and that lagged automaticity predicted HSE, indicating a positive feedback mechanism in habit building. Furthermore, we found that lagged HSE predicted less MI during habit performance. A multilevel mediation analysis showed significant effects of lagged HSE (Level 1) and aggregated HSE (Level 2) on MI, which were both partially mediated by automaticity. These results show the importance of defining the specificity of self-efficacy beliefs and how they interact with automaticity in the habit building process. [less ▲]

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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 detailTesting market regulations in experimental asset markets –The case of margin purchases
Neugebauer, Tibor UL; Füllbrunn, Sascha

in Journal of Economic Behavior and Organization (2021)

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See detailConFuzzius: A Data Dependency-Aware Hybrid Fuzzer for Smart Contracts
Ferreira Torres, Christof UL; Iannillo, Antonio Ken UL; Gervais, Arthur et al

in European Symposium on Security and Privacy, Vienna 7-11 September 2021 (2021, September)

Smart contracts are Turing-complete programs that are executed across a blockchain. Unlike traditional programs, once deployed, they cannot be modified. As smart contracts carry more value, they become ... [more ▼]

Smart contracts are Turing-complete programs that are executed across a blockchain. Unlike traditional programs, once deployed, they cannot be modified. As smart contracts carry more value, they become more of an exciting target for attackers. Over the last years, they suffered from exploits costing millions of dollars due to simple programming mistakes. As a result, a variety of tools for detecting bugs have been proposed. Most of these tools rely on symbolic execution, which may yield false positives due to over-approximation. Recently, many fuzzers have been proposed to detect bugs in smart contracts. However, these tend to be more effective in finding shallow bugs and less effective in finding bugs that lie deep in the execution, therefore achieving low code coverage and many false negatives. An alternative that has proven to achieve good results in traditional programs is hybrid fuzzing, a combination of symbolic execution and fuzzing. In this work, we study hybrid fuzzing on smart contracts and present ConFuzzius, the first hybrid fuzzer for smart contracts. ConFuzzius uses evolutionary fuzzing to exercise shallow parts of a smart contract and constraint solving to generate inputs that satisfy complex conditions that prevent evolutionary fuzzing from exploring deeper parts. Moreover, ConFuzzius leverages dynamic data dependency analysis to efficiently generate sequences of transactions that are more likely to result in contract states in which bugs may be hidden. We evaluate the effectiveness of ConFuzzius by comparing it with state-of-the-art symbolic execution tools and fuzzers for smart contracts. Our evaluation on a curated dataset of 128 contracts and a dataset of 21K real-world contracts shows that our hybrid approach detects more bugs than state-of-the-art tools (up to 23%) and that it outperforms existing tools in terms of code coverage (up to 69%). We also demonstrate that data dependency analysis can boost bug detection up to 18%. [less ▲]

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See detailNo more Piecemeal Tactics
Kafteranis, Dimitrios UL; Robert, Brochhaus

E-print/Working paper (2021)

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See detailFeasibility of ERA5 integrated water vapor trends for climate change analysis in continental Europe: An evaluation with GPS (1994–2019) by considering statistical significance
Yuan, Peng; Hunegnaw, Addisu UL; Alshawaf, Fadwa et al

in Remote Sensing of Environment (2021), 260(112416),

Although the statistical significances for the trends of integrated water vapor (IWV) are essential for a correct interpretation of climate change signals, obtaining accurate IWV trend estimates with ... [more ▼]

Although the statistical significances for the trends of integrated water vapor (IWV) are essential for a correct interpretation of climate change signals, obtaining accurate IWV trend estimates with realistic uncertainties remains a challenge. This study evaluates the feasibility of the IWV trends derived from the newly released fifth generation European Centre for Medium-Range Weather Forecasts (ECMWF) atmospheric reanalysis (ERA5) for climate change analysis in continental Europe. This is achieved by comparing the trends derived from in-situ ground-based Global Positioning System (GPS)’s daily IWV series from 1994 to 2019 at 109 stations. The realistic uncertainties and statistical significances of the IWV trends are evaluated with the time series analysis on their noise characteristics and proper noise models. Results show that autoregressive moving average ARMA(1,1) noise model is preferred rather than the commonly assumed white noise (WN) or first-order autoregressive AR(1) noise for about 68% of the ERA5 and GPS IWV series. An improper noise model would misevaluate the trend uncertainty of an IWV time series, compared with its specific preferred noise model. For example, ARMA(1,1) may misevaluate the standard deviations of their trend estimates (0.1–0.3 kg m−2 decade−1) by 10%. Nevertheless, ARMA(1,1) is recommended as the default noise model for the ERA5 and GPS IWV series. However, the preferred noise model for each ERA5 minus GPS (E-G) IWV series should be specifically determined, because the AR(1)-related models can result in an underestimation on its trend uncertainty by 90%. In contrast, power-law (PL) model can lead to an overestimation by up to nine times. The E-G IWV trends are within −0.2–0.4 kg m−2 decade−1, indicating that the ERA5 is a potential data source of IWV trends for climate change analysis in continental Europe. The ERA5 and GPS IWV trends are consistent in their magnitudes and geographical patterns, lower in Northwest Europe (0–0.4 kg m−2 decade−1) but higher around the Mediterranean Sea (0.6–1.4 kg m−2 decade−1). [less ▲]

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See detailKnowledge assessment with concept maps: Opportunities and challenges
Rohles, Björn UL; Koenig, Vincent UL; Fischbach, Antoine UL et al

Scientific Conference (2021, July)

21st-century digital society poses tremendous challenges for education and assessment. Learners have to understand the complex relations between diverse topics and learn how to learn their entire lives ... [more ▼]

21st-century digital society poses tremendous challenges for education and assessment. Learners have to understand the complex relations between diverse topics and learn how to learn their entire lives. Concept mapping is a promising approach to address these issues. It is a method that uses concepts connected by labeled links to visualize a semantic network of knowledge. Concept mapping is predestined for a digital approach because it allows for easy interactive editing, innovative test items, and incorporation of multimodal information. Concept mapping is available for summative and formative assessment and, thus, provides the opportunity to become a vital part of modern education. The biggest advantage of concept mapping (i.e., a comprehensive and yet comprehensible visualization of complex relations) also represents the biggest challenge when it comes to assessment with - and scoring of - concept maps. The first challenge is the enormous amount of indicators used for scoring concept maps in assessment. A second challenge comes from the fact that educators using concept mapping in their assessment have to understand and interpret the indicators that are used in scoring concept maps. This presentation reports on a Ph.D. project that investigates digital concept mapping in the context of knowledge assessment from a user experience perspective. The results are based on, first, a comprehensive international systematic literature review on concept map scoring, and second, three empirical studies covering the needs and experiences of learners and educators in concept mapping. It presents key findings from the iterative user experience design of a concept mapping tool as part of the online assessment platform OASYS, an overview of indicators used in concept map scoring, and research opportunities in knowledge assessment with concept maps. Finally, it stresses the value that user experience design brings to knowledge assessment with concept maps. [less ▲]

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See detailSmall in size, great in significance: conspicilla and perspicilla in the visual arts of the Low Countries around 1600
Koeleman, Floor UL

Scientific Conference (2021, July)

A largely forgotten constcamer painting from the early seventeenth century shows eyeglasses and a telescope in close proximity. The inclusion of these extensions of sight in The Five Senses of the Musée ... [more ▼]

A largely forgotten constcamer painting from the early seventeenth century shows eyeglasses and a telescope in close proximity. The inclusion of these extensions of sight in The Five Senses of the Musée Magnin (Dijon) seems to allude to the implicit link between the two. As tools to observe with and through, these instruments visualize the limits of human perception and the ability to alter the scale of the visible world. The Five Senses was created in Antwerp around the same time the telescope first appeared in textual sources, namely 1608. However, the optical instrument is likely to have existed for years by then. This paper investigates if any references to the telescope in the visual arts predate the first written evidence of its invention. For artists the early telescope was probably not that challenging an object to represent. The exterior, a simple tube characterized by a diaphragm, housed two lenses made by the same glass industry that manufactured eyeglasses. This paper takes a closer look at the imagery of eyeglasses and telescopes, depicted in the visual arts of the late sixteenth and early seventeenth centuries. The meaning assigned to these instruments can be inferred from the context in which they are presented and their relative scale. Together eyeglasses and telescopes feature prominently in constcamer paintings dedicated to visual perception, understood both physically and metaphysically. While the exact date of creation remains subject to debate, The Five Senses probably contains the earliest known depiction of a telescope – true to scale. [less ▲]

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See detailDemocracy, Freedom and Truth at a Time of Digital Disruption: An equation with three unknowns?
Danescu, Elena UL

in Višňovský, Ján; Radošinská (Eds.) Fake News Is Bad News - Hoaxes, Half-truths and the Nature of Today's Journalism (2021)

The pattern of a knowledge-based society relies to a large extent on digital technologies and intangible outputs and generate considerable transnational financial flows and gains. These technologies also ... [more ▼]

The pattern of a knowledge-based society relies to a large extent on digital technologies and intangible outputs and generate considerable transnational financial flows and gains. These technologies also play a key role in providing free access to data and information, encouraging citizen participation in public decision-making, fostering transparency and scrutiny of government action and mobilising new players capable of identifying alternative means of civic and political participation worldwide. At the same time, the increasingly impact of online platforms in manipulating transnational public debates, and the surge in extremist groups using the digital ecosystem to incite hatred, hostility and violence are a warning sign that these modes of communication may be having an adverse effect on democracy and that the boundary between fact and fiction is not as clear as we may like to think. The US presidential election campaign and the Brexit referendum (2016), the theories about COVID-19 (that have flooded the web since 2019), the terrorist attack against French teacher Samuel Paty (16 October 2020) all highlight these trends. When the majority of the world’s citizens are using online media as their main source of information, the proliferation of disinformation and the related threat of radicalism and extremism have led to a growing awareness of these issues at international- and European Union level. What can be done to tackle the situation? How should the democratic states with new forms of private power in the algorithmic society? Where should the line be drawn between freedom of expression and media pluralism on the one hand, and intrusion and censorship of dissenting opinions on the other? How should information be defended as a fundamental right? Is there a moral or ethical code when it comes to information? How can be created an environment that is conducive to inclusive, pluralistic public debate? How to equip citizens to develop a critical approach and to take informed decisions? How to balance innovation with the need to ensure transparency and fairness? Could we be witnessing a situation in which algorithms are “dissolving” democracy? Drawing on the archives of the international and European multilateral organisations (UN/UNESCO, Council of Europe, the Organisation for Security and Cooperation in Europe, the European Union) and several public and private stakeholders worldwide, this chapter proposes: a) to take stock of the issues and challenges raised by the proliferation of fake news, social media and algorithms, and their impact on freedom and democracy; b) to review the regulatory provisions implemented in this area at European and international level; and c) to identify future prospects. [less ▲]

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See detailBoys don't cry (or do the dishes): Family size and the housework gender gap
Menta, Giorgia UL; Lepinteur, Anthony UL

in Journal of Economic Behavior and Organization (2021), 186

We here use data from the British Cohort Study (BCS) to link family size to age-16 children’s contribution to household chores and the adult housework gender gap. Assuming that home production is an ... [more ▼]

We here use data from the British Cohort Study (BCS) to link family size to age-16 children’s contribution to household chores and the adult housework gender gap. Assuming that home production is an increasing function of family size and using an instrument to account for the endogeneity of fertility, we show that larger families have a different effect on boys and girls at age 16: girls in large families are significantly more likely to contribute to housework, with no effect for boys. We then show that childhood family size affects the housework gender gap between the cohort members and their partners at age 34. Women who grew up in larger families are more likely to carry out a greater share of household tasks in adulthood, as compared to women from smaller families. In addition, growing up in a large family makes cohort members more likely to sort into households with a wider housework gender gap as adults. We show that the persistent effect of family size is due to the adoption of behaviours in line with traditional gender roles: a lower likelihood of employment and shorter commutes for women, along with a higher employment probability for their partners. [less ▲]

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See detailLocal Meanings of Proportionality
Marketou, Afroditi UL

Book published by Cambridge University Press (2021)

Proportionality increasingly dominates legal imagination. Initially conceived of as a principle that regulates police action, today it is progressively established as an advanced tool of liberal ... [more ▼]

Proportionality increasingly dominates legal imagination. Initially conceived of as a principle that regulates police action, today it is progressively established as an advanced tool of liberal constitutional science. Its spread, accompanied by a global paradigm of constitutional rights, appears to be an irresistible natural development. This thesis was inspired by the intuition that even though courts and lawyers around the world reason more and more in proportionality terms, proportionality can mean very different things in different contexts, even within the same legal system. While the relevant literature has paid little attention to differences in the use of proportionality, identifying the local meanings of proportionality is crucial to making sense of its spread, to assessing its success, and to appraising the possibility of convergence between legal systems. Through an in-depth study and comparison of the use of proportionality by legal actors in France, England and Greece, this work shows that the local meanings of proportionality are not simply deviant applications of a global model. Instead, they reflect the legal cultures in which they evolve, local paths of cultural change and local patterns of Europeanisation. [less ▲]

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