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See detailYolanda von Vianden und das Yolanda-Epos
Sieburg, Heinz UL

E-print/Working paper (in press)

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See detailThe edge-based strain smoothing method for compressible and nearly incompressible non-linear elasticity for solid mechanics
Lee, Chang-Kye; Mihai, L. Angela; Kerfriden, Pierre et al

E-print/Working paper (in press)

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See detailThe Geometry of Supersymmetry
Poncin, Norbert UL; Schouten, Sarah

E-print/Working paper (2022)

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See detailOptimal lockdown and vaccination policies to contain the spread of a mutating infectious disease
Prieur, Fabien; Ruan, Weihua; Zou, Benteng UL

E-print/Working paper (2022)

We develop a piecewise deterministic control model to study optimal lockdown and vaccination policies to manage a pandemic. Lockdown is modeled as an impulse control that allows the system to switch from ... [more ▼]

We develop a piecewise deterministic control model to study optimal lockdown and vaccination policies to manage a pandemic. Lockdown is modeled as an impulse control that allows the system to switch from one restriction regime of restrictions to another. Vaccination policy is a continuous control. Decisions are taken under the risk of mutations of the disease, with repercussions on the transmission rate. The decision maker follows a cost minimization objective. We first characterize the optimality conditions for impulse control and show how the prospect of a mutation affects the decision maker's choice by inducing her to anticipate the relative benefit of a regime change after a mutation has occurred. Under some parametric conditions, our problem admits infinitely many value functions. We show the existence of a minimum value function that is a natural candidate to the solution given the nature of the problem. Focusing on this specific value function, we finally study the features of the optimal policy, especially the timing of impulse control. We prove that uncertainty surrounding future \bad" vs. \good" mutation of the disease expedites vs. delays the adoption of lockdown measures. [less ▲]

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See detailWhy and when coalitions split? An alternative analytical approach with an application to environmental agreements
Boucekkine, Raouf; Camacho, Carmen; Ruan, Weihua et al

E-print/Working paper (2022)

We use a parsimonious two-stage differential game setting where the duration of the first stage, the coalition stage, depends on the will of a particular player to leave the coalition through an explicit ... [more ▼]

We use a parsimonious two-stage differential game setting where the duration of the first stage, the coalition stage, depends on the will of a particular player to leave the coalition through an explicit timing variable. By specializing in a standard linear-quadratic environmental model augmented with a minimal constitutional setting for the coalition (payoff share parameter), we are able to analytically extract several nontrivial findings. Three key aspects drive the results: the technological gap as an indicator of heterogeneity across players, the constitution of the coalition and the intensity of the public bad (here, the pollution damage). We provide with a full analytical solution to the two-stage differential game. In particular, we characterize the intermediate parametric cases leading to optimal nite time splitting. A key characteristic of these finite-time-lived coalitions is the requirement of the payoff share accruing to the splitting country to be large enough. Incidentally, our two-stage differential game setting reaches the conclusion that splitting countries are precisely those which use to benefit the most from the coalition. Constraining the payoff share to be low by Constitution may lead to optimal everlasting coalitions only provided initial pollution is high enough, which may cover the emergency cases we are witnessing nowadays. [less ▲]

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See detailSolvability of systems of invariant differential equations on H2 and beyond
Palmirotta, Guendalina UL; Olbrich, Martin UL

E-print/Working paper (2022)

We show how the Fourier transform for distributional sections of vector bundles over symmetric spaces of non-compact type G/K can be used for questions of solvability of systems of invariant differential ... [more ▼]

We show how the Fourier transform for distributional sections of vector bundles over symmetric spaces of non-compact type G/K can be used for questions of solvability of systems of invariant differential equations in analogy to Hörmander’s proof of the Ehrenpreis-Malgrange theorem. We get complete solvability for the hyperbolic plane H2 and partial results for products H^2 × · · · × H^2 and the hyperbolic 3-space H^3. [less ▲]

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See detailDie Vielfalt der Sozialen Arbeit in Luxemburg und die Arbeitsmarktzahlen 2021
Böwen, Petra UL; Flammang, Manou Laure

E-print/Working paper (2022)

Dieser Newsletter beschreibt den Arbeitsmarkt der Sozialen Arbeit in Luxemburg 2021, gibt einen Überblick über die Berufsqualifikationen und die Vielfalt der Praxisfelder und spezifischen Arbeitsbereiche.

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See detailDelorme’s intertwining conditions for sections of homogeneous vector bundles on two and three dimensional hyperbolic spaces
Palmirotta, Guendalina UL; Olbrich, Martin UL

E-print/Working paper (2022)

The description of the Paley-Wiener space for compactly supported smooth functions C_c^∞(G) on a semi-simple Lie group G involves certain intertwining conditions that are difficult to handle. In the ... [more ▼]

The description of the Paley-Wiener space for compactly supported smooth functions C_c^∞(G) on a semi-simple Lie group G involves certain intertwining conditions that are difficult to handle. In the present paper, we make them completely explicit for G = SL(2, R)^d (d ∈ N) and G = SL(2, C). Our results are based on a defining criterion for the Paley-Wiener space, valid for general groups of real rank one, that we derive from Delorme’s proof of the Paley-Wiener theorem. In a forthcoming paper, we will show how these results can be used to study solvability of invariant differential operators between sections of homogeneous vector bundles over the corresponding symmetric spaces. [less ▲]

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See detailEstimating a regression function in exponential families by model selection
Chen, Juntong UL

E-print/Working paper (2022)

Detailed reference viewed: 70 (26 UL)
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See detailPandemic Impacts on Sustainability and Hartwick’s Rule
Mavi, Can; Zou, Benteng UL

E-print/Working paper (2022)

In this study, we present a modified Hartwick rule encompassing the dynamics of pandemic, such as COVID-19. In our setting, the labor productivity gradually improves after the pandemic shock and may even ... [more ▼]

In this study, we present a modified Hartwick rule encompassing the dynamics of pandemic, such as COVID-19. In our setting, the labor productivity gradually improves after the pandemic shock and may even go beyond its pre-pandemic level due to the remote work and digitalization as also suggested by the empirical evidence. We demonstrate that a gradual labor productivity increase helps to conserve natural resources. We provide a theoretical foundation for a“sooner-the-better" strategy to control a pandemic, and we show that policy maker should implement a “whatever it costs” response to ensure that the transmission rate of the virus is below the recovery rate from the very beginning of the pandemic. Otherwise, the economy cannot have a sustained utility. We also analyze the implications of an “uncertain” pandemic on the intertemporal dynamics of natural resource and capital accumulation under the maximin criterion. Another important finding is that there exists a new economic and public health trade-off since a strong prevention policy is shown to decrease capital accumulation. [less ▲]

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See detailFINCITY -- Excerpt from project description
Hesse, Markus UL; Dörry, Sabine; Sigler, Thomas

E-print/Working paper (2022)

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See detailTowards Generalizable Machine Learning for Chest X-ray Diagnosis with Multi-task learning
Ghamizi, Salah UL; Garcia Santa Cruz, Beatriz UL; Temple, Paul et al

E-print/Working paper (2022)

Clinicians use chest radiography (CXR) to diagnose common pathologies. Automated classification of these diseases can expedite analysis workflow, scale to growing numbers of patients and reduce healthcare ... [more ▼]

Clinicians use chest radiography (CXR) to diagnose common pathologies. Automated classification of these diseases can expedite analysis workflow, scale to growing numbers of patients and reduce healthcare costs. While research has produced classification models that perform well on a given dataset, the same models lack generalization on different datasets. This reduces confidence that these models can be reliably deployed across various clinical settings. We propose an approach based on multitask learning to improve model generalization. We demonstrate that learning a (main) pathology together with an auxiliary pathology can significantly impact generalization performance (between -10% and +15% AUC-ROC). A careful choice of auxiliary pathology even yields competitive performance with state-of-the-art models that rely on fine-tuning or ensemble learning, using between 6% and 34% of the training data that these models required. We, further, provide a method to determine what is the best auxiliary task to choose without access to the target dataset. Ultimately, our work makes a big step towards the creation of CXR diagnosis models applicable in the real world, through the evidence that multitask learning can drastically improve generalization. [less ▲]

Detailed reference viewed: 61 (8 UL)
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See detailThe Irreversible Pollution Game
Boucekkine, Raouf; Ruan, Weihua; Zou, Benteng UL

E-print/Working paper (2022)

We study a 2-country differential game with irreversible pollution. Irresability is of a hard type: above a certain threshold level of pollution, the self-cleaning capacity of Nature drops to zero ... [more ▼]

We study a 2-country differential game with irreversible pollution. Irresability is of a hard type: above a certain threshold level of pollution, the self-cleaning capacity of Nature drops to zero. Accordingly, the game includes a non-concave feature, and we characterize both the cooperative and non-cooperative versions with this general non-LQ property. We deliver full analytical results for the existence of Markov Perfect Equilibria. We first demonstrate that when pollution costs are equal across players (symmetry), irreversible pollution regimes are more frequently reached than under cooperation. Second, we study the implications of asymmetry in the pollution cost. We find far nontrivial results on the reachability of the irreversible regime. However, we unambiguously prove that, for the same total cost of pollution, provided the irreversible regime is reached in both the symmetric and asymmetric cases, long-term pollution is larger in the symmetric case, reflecting more intensive free-riding under symmetry. [less ▲]

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See detailDer Arbeitsmarkt der Sozialen Arbeit 2020 = Le marché de l'emploi du secteur social en 2020
Böwen, Petra UL; Flammang, Manou Laure UL

E-print/Working paper (2022)

Dieser Newsletter beschreibt den Arbeitsmarkt der Sozialen Arbeit in Luxemburg 2020 und die Entwicklung der Zahlen in einigen Bereichen für 2018 bis 2020. Die Daten stammen von einem fortlaufenden ... [more ▼]

Dieser Newsletter beschreibt den Arbeitsmarkt der Sozialen Arbeit in Luxemburg 2020 und die Entwicklung der Zahlen in einigen Bereichen für 2018 bis 2020. Die Daten stammen von einem fortlaufenden Forschungsprojekt des PraxisBüros der Universität Luxemburg. Der Newsletter stellt eine Auswahl an Statistiken dar, z.B. bezüglich der meist gefragten Qualifikationsniveaus, der Verteilung der Praxisfelder, der Verteilung der Stellenangebote zwischen öffentlichen, kommunalen, gemeinnützigen und privaten Trägern und der erfassten enormen Diskrepanz zwischen Nachfrage und Angebot an qualifizierten Professionellen in der Sozialen Arbeit. Desweiteren werden Entwicklungstrends- vor allem zu Thema Aus- und Weiterbildung aufgezeigt. [less ▲]

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See detailHow Patent Rights Affect University Science
Berge, Laurent; Doherr, Thorsten; Hussinger, Katrin UL

E-print/Working paper (2022)

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See detailBuilding Regional Payment Areas: The Single Rule Book Approach
Zetzsche, Dirk Andreas UL; Lammer, Thomas; Gazi, S. et al

E-print/Working paper (2022)

Detailed reference viewed: 24 (0 UL)
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See detailA topological Paley-Wiener-Schwartz Theorem for sections of homogeneous vector bundles on G/K
Palmirotta, Guendalina UL; Olbrich, Martin UL

E-print/Working paper (2022)

We study the Fourier transform for compactly supported distributional sections of complex homogeneous vector bundles on symmetric spaces of non-compact type X = G/K. We prove a characterisation of their ... [more ▼]

We study the Fourier transform for compactly supported distributional sections of complex homogeneous vector bundles on symmetric spaces of non-compact type X = G/K. We prove a characterisation of their range. In fact, from Delorme’s Paley-Wiener theorem for compactly supported smooth functions on a real reductive group of Harish-Chandra class, we deduce topological Paley-Wiener and Paley-Wiener- Schwartz theorems for sections. [less ▲]

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See detailDLT-Based Enhancement of Cross-Border Payment Efficiency – a Legal and Regulatory Perspective
Zetzsche, Dirk Andreas UL; Anker-Sorensen, Linn; Passador, Maria et al

E-print/Working paper (2022)

Detailed reference viewed: 37 (2 UL)
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See detailA restless badit approach for capacitated condition based maintenance scheduling
Demirci, Ece; Arts, Joachim UL; Van Houtum, Geert-Jan

E-print/Working paper (2022)

Detailed reference viewed: 88 (11 UL)
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See detailMechanisms to buffer variability in cell regulation motifs close to criticality
Proverbio, Daniele UL; Noronha Montanari, Arthur UL; Skupin, Alexander UL et al

E-print/Working paper (2022)

Bistable biological regulatory systems need to cope with stochastic noise to fine-tune their function close to bifurcation points. Here, we study stability properties of this regime in generic systems to ... [more ▼]

Bistable biological regulatory systems need to cope with stochastic noise to fine-tune their function close to bifurcation points. Here, we study stability properties of this regime in generic systems to demonstrate that cooperative interactions buffer system variability, hampering noise-induced regime shifts. Our analysis also shows that, in the considered cooperativity range, impending regime shifts can be generically detected by statistical early warning signals from distributional data. Our generic framework, based on minimal models, can be used to extract robustness and variability properties of more complex models and empirical data close to criticality. [less ▲]

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See detailWavelet methods to study the pointwise regularity of the generalized Rosenblatt process
Daw, Lara UL; Loosveldt, Laurent UL

E-print/Working paper (2022)

We prove that we can identify three types of pointwise behaviour in the regularity of the (generalized) Rosenblatt process. This extends to a non Gaussian setting previous results known for the ... [more ▼]

We prove that we can identify three types of pointwise behaviour in the regularity of the (generalized) Rosenblatt process. This extends to a non Gaussian setting previous results known for the (fractional) Brownian motion. On this purpose, fine bounds on the increments of the Rosenblatt process are needed. Our analysis is essentially based on various wavelet methods. [less ▲]

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See detailThe Impact of the Asset Purchase Programme on Systemic Risk in the Euro Area: Is There a Threat?
Chavarro Sanchez, Leidy; Nadal De Simone, Francisco; Lehnert, Thorsten UL

E-print/Working paper (2021)

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See detailDiversity on the screen
Zanaj, Skerdilajda UL

E-print/Working paper (2021)

Detailed reference viewed: 102 (8 UL)
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See detailAuswirkungen der Covid-19-Krise auf die Soziale Arbeit in Luxemburg aus Sicht der Praxis : Ergebnisse einer Online-Befragung im Sommer 2020
Flammang, Manou Laure UL; Böwen, Petra UL

E-print/Working paper (2021)

This publication presents the findings of an online survey on the impact of the Covid-19 crisis on social work in Luxembourg from the perspective of practitioners. It shows what effects the crisis as well ... [more ▼]

This publication presents the findings of an online survey on the impact of the Covid-19 crisis on social work in Luxembourg from the perspective of practitioners. It shows what effects the crisis as well as the hygiene and protection measures had on daily social work practice, on the addressees and on the practitioners themselves. The findings are then reflected upon and discussed in relation to international research findings and professional publications on the topic of social work in times of Covid-19. [less ▲]

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See detailEarthquakes and Mental Health
Bertinelli, Luisito UL; Mahé, Clotilde; Strobl, Eric

E-print/Working paper (2021)

Earthquakes may seriously deteriorate mental health by generating fear and stress as a result of economic and human losses. However, mental health has also been found to improve as a result of greater ... [more ▼]

Earthquakes may seriously deteriorate mental health by generating fear and stress as a result of economic and human losses. However, mental health has also been found to improve as a result of greater social cohesion in affected communities after the event. We examine the short-run effects of earthquakes on a wide set of mental health outcomes in Ecuador. To this end, we combine hospital admissions, death records, and survey data with precise measures of local seismic activity to exploit the plausibly random spatial and temporal nature of earthquake intensity. We find that damaging earthquakes decrease the propensity to be admitted, the number of days of hospitalisation for mental and behavioural disorders, and deaths due to suicide. Estimates from nationally-representative surveys provide suggestive evidence of increased life satisfaction, trust, and religious observance, and thus provide a possible explanation for the fall in admissions and suicides after an earthquake. [less ▲]

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See detailRequirements And Threat Models of Adversarial Attacks and Robustness of Chest X-ray classification
Ghamizi, Salah UL; Cordy, Maxime UL; Papadakis, Mike UL et al

E-print/Working paper (2021)

Vulnerability to adversarial attacks is a well-known weakness of Deep Neural Networks. While most of the studies focus on natural images with standardized benchmarks like ImageNet and CIFAR, little ... [more ▼]

Vulnerability to adversarial attacks is a well-known weakness of Deep Neural Networks. While most of the studies focus on natural images with standardized benchmarks like ImageNet and CIFAR, little research has considered real world applications, in particular in the medical domain. Our research shows that, contrary to previous claims, robustness of chest x-ray classification is much harder to evaluate and leads to very different assessments based on the dataset, the architecture and robustness metric. We argue that previous studies did not take into account the peculiarity of medical diagnosis, like the co-occurrence of diseases, the disagreement of labellers (domain experts), the threat model of the attacks and the risk implications for each successful attack. In this paper, we discuss the methodological foundations, review the pitfalls and best practices, and suggest new methodological considerations for evaluating the robustness of chest xray classification models. Our evaluation on 3 datasets, 7 models, and 18 diseases is the largest evaluation of robustness of chest x-ray classification models. We believe our findings will provide reliable guidelines for realistic evaluation and improvement of the robustness of machine learning models for medical diagnosis. [less ▲]

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See detailA global carbon tax? Why firm mobility and heterogeneity matters
Zanaj, Skerdilajda UL

E-print/Working paper (2021)

Detailed reference viewed: 217 (14 UL)
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See detailLabor Market Effects of Technology Shocks biased Toward the Traded Sector
Bertinelli, Luisito UL; Cardi; Restout

E-print/Working paper (2021)

Motivated by recent evidence pointing at an increasing contribution of asymmetric shocks across sectors to economic fluctuations, we explore the labor market effects of technology shocks biased toward the ... [more ▼]

Motivated by recent evidence pointing at an increasing contribution of asymmetric shocks across sectors to economic fluctuations, we explore the labor market effects of technology shocks biased toward the traded sector. Our VAR evidence for seventeen OECD countries reveals that the non-traded sector alone drives the increase in total hours worked following a technology shock that increases permanently traded relative to non-traded TFP. The shock generates a reallocation of labor toward the non-traded sector which contributes to 35% on average of the rise in non-traded hours worked. Both labor reallocation and variations in labor income shares are found empirically connected with factor-biased technological change. Our quantitative analysis shows that a two-sector open economy model with flexible prices can reproduce the labor market effects we document empirically once we allow for imperfect mobility of labor, gross substitutability between home- and foreign-produced traded goods, and factor-biased technological change. When calibrating the model to country-specific data, its ability to account for the cross-country reallocation and redistributive effects we estimate increases once we let factor-biased technological change vary between sectors and across countries. [less ▲]

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See detailThe role of economic complexity on the formation of gender roles
Zanaj, Skerdilajda UL

E-print/Working paper (2021)

Detailed reference viewed: 147 (18 UL)
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See detailQKD parameter estimation by two-universal hashing leads to faster convergence to the asymptotic rate
Ostrev, Dimiter UL

E-print/Working paper (2021)

This paper proposes and proves security of a QKD protocol which uses two-universal hashing instead of random sampling to estimate the number of bit flip and phase flip errors. This protocol dramatically ... [more ▼]

This paper proposes and proves security of a QKD protocol which uses two-universal hashing instead of random sampling to estimate the number of bit flip and phase flip errors. This protocol dramatically outperforms previous QKD protocols for small block sizes. More generally, for the two-universal hashing QKD protocol, the difference between asymptotic and finite key rate decreases with the number $n$ of qubits as $cn^{-1}$, where $c$ depends on the security parameter. For comparison, the same difference decreases no faster than $c'n^{-1/3}$ for an optimized protocol that uses random sampling and has the same asymptotic rate, where $c'$ depends on the security parameter and the error rate. [less ▲]

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See detailImpact of mining boom on the quality of public goods in Sub-Saharan Africa
Bertinelli, Luisito UL; Bourgain, Arnaud UL

E-print/Working paper (2021)

In this paper, we investigate the impact of public mining revenues on perception indicators of public goods quality in five mining countries that have recently experienced a boom in their government ... [more ▼]

In this paper, we investigate the impact of public mining revenues on perception indicators of public goods quality in five mining countries that have recently experienced a boom in their government revenues: Burkina Faso, Ghana, D.R. Congo, Tanzania, and Zambia. The effect of the tax revenue boom is identified using a difference-in-differences estimation strategy. Our estimations indicate that people living in mining regions as having a sense of structural disadvantage in terms of the provision of public goods; however, this perception is pro-cyclical in the presence of resource booms/busts. Our results hold even after taking account of the possible endogeneity of our measure of resource revenue. [less ▲]

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See detailEvaluation of TPMS Signal Propagation in a Heavy Commercial Vehicle Environement
Rida, Ahmad UL; Ridha, Soua; Engel, Thomas UL

E-print/Working paper (2021)

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See detailCovid-Kids II. Survey for children aged 6 to 16 about their experiences during the Covid-19 pandemic
Kirsch, Claudine UL; Peluso, Eugenio; Andreoli, Francesco et al

E-print/Working paper (2021)

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See detailInsider’s problem in the trinomial model: a discrete jump process point of view
Halconruy, Hélène UL

E-print/Working paper (2021)

In an incomplete market underpinned by the trinomial model, we consider two investors: an ordinary agent whose decisions are driven by public information and an insider who possesses from the beginning a ... [more ▼]

In an incomplete market underpinned by the trinomial model, we consider two investors: an ordinary agent whose decisions are driven by public information and an insider who possesses from the beginning a surplus of information encoded through a random variable for which he or she knows the outcome. Through the definition of an auxiliary model based on a marked binomial process, we handle the trinomial model as a volatility one, and use the stochastic analysis and Malliavin calculus toolboxes available in that context. In particular, we connect the information drift, i.e. the drift to eliminate in order to preserve the martingale property within an initial enlargement of filtration in terms of Malliavin’s derivative. We solve explicitly the agent and the insider expected logarithmic utility maximization problems and provide a Ocone-Karatzas type formula for replicable claims. We identify insider’s expected additional utility with the Shannon entropy of the extra information, and examine then the existence of arbitrage opportunities for the insider. [less ▲]

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See detailThe good, the bad, and the asymmetric: Evidence from a new conditional density model
Kostyrka, Andreï UL; Malakhov, Dmitry

E-print/Working paper (2021)

We propose a novel univariate conditional density model and decompose asset returns into a sum of copula-connected unobserved ‘good’ and ‘bad’ shocks. The novelty of this approach comes from two factors ... [more ▼]

We propose a novel univariate conditional density model and decompose asset returns into a sum of copula-connected unobserved ‘good’ and ‘bad’ shocks. The novelty of this approach comes from two factors: we explicitly model correlation between unobserved shocks and allow for the presence of copula-connected discrete jumps. The proposed framework is very flexible and subsumes other models, such as ‘bad environments, good environments’. Our model shows certain hidden characteristics of returns, explains investors’ behaviour in greater detail, and yields better forecasts of risk measures. The in-sample and out-of-sample performance of our model is better than that of 40 popular GARCH variants. A Monte-Carlo simulation shows that the proposed model recovers the structural parameters of the unobserved dynamics. We estimate the model on S&P 500 data and find that time-dependent non-negative covariance between ‘good’ and ‘bad’ shocks with a leverage-like effect is an important component of total variance. Asymmetric reaction to shocks is present almost in all characteristics of returns. Conditional distribution of seems to be very time-dependent with skewness both in the centre and tails. We conclude that continuous shocks are more important than discrete jumps at least at daily frequency. [less ▲]

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See detailLes langues dans les offres d'emploi au Luxembourg (1984-2019)
Pigeron-Piroth, Isabelle UL; Fehlen, Fernand UL

E-print/Working paper (2021)

À partir d’un échantillon d’offres d’emploi publiées dans le Luxemburger Wort, portant sur la période 1984-2019, cette étude décrit l’évolution des compétences linguistiques exigées ou souhaitées sur le ... [more ▼]

À partir d’un échantillon d’offres d’emploi publiées dans le Luxemburger Wort, portant sur la période 1984-2019, cette étude décrit l’évolution des compétences linguistiques exigées ou souhaitées sur le marché du travail du Luxembourg. Après une présentation contextuelle de la situation linguistique et de l’emploi au Luxembourg, l’analyse empirique des quelques 8 340 offres d’emploi de notre échantillon constitue le cœur de cette publication. Aux divers tableaux et graphiques illustrant notre propos s’ajoutent des décryptages de la sémantique utilisée dans les offres d’emploi publiées, utiles à la compréhension des besoins linguistiques dans un marché du travail plurilingue et international. [less ▲]

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See detailAdaptively Secure Laconic Function Evaluation for NC1
Agrawal, Shweta; Rosie, Razvan UL

E-print/Working paper (2021)

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See detailCloturing Deliberation
Anesi, Vincent UL; Safronov, Mikhail

E-print/Working paper (2021)

We study how the institutional arrangements for ending deliberation --- the "cloture rules" --- interact with collective learning to affect the outcomes of decision making in committees. In contrast to ... [more ▼]

We study how the institutional arrangements for ending deliberation --- the "cloture rules" --- interact with collective learning to affect the outcomes of decision making in committees. In contrast to much of the previous literature on deliberative commit tees, this paper makes a distinction between the final votes over policy proposals and the cloture votes that bring them about. Using this approach, we explore how cloture rules influence the course of deliberation, the likelihood of inefficient deliberative outcomes, the circumstances surrounding failures to bring proposals to a final vote, and the distribution of power among committee members in the deliberative process. We also use our simple model to examine the issue of the stability of cloture rules, characterizing the rules that no coalition of committee members is able or willing to overturn. We show in particular that all cloture rules are dynamically stable. [less ▲]

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See detailLooking for the `Best and Brightest': Hiring difficulties and high-skilled foreign workers
Raux, Morgan UL

E-print/Working paper (2021)

This paper studies the complementarity between domestic and foreign skilled workers. It develops a simple model where employers seek to recruit a foreign worker when finding domestic workers takes more ... [more ▼]

This paper studies the complementarity between domestic and foreign skilled workers. It develops a simple model where employers seek to recruit a foreign worker when finding domestic workers takes more time. This paper confirms the predictions of the model. I rely on a within-firm within-occupation identification strategy to compare recruitment decisions made by a given employer for similar positions that differ in job posting duration. To identify this relationship, I have collected and assembled a new and original dataset at the job level. I match online job postings to administrative data on labor condition applications (LCAs) submitted as the first step in applying for H-1B temporary skilled worker visas. I find that employers are 28 percent more likely to submit an LCA when the job posting duration is one standard deviation longer. I provide evidence suggesting that this phenomenon is due to insufficient domestic labor supply in these occupations. [less ▲]

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See detailCultural differences and immigrants' wages
Raux, Morgan UL

E-print/Working paper (2021)

In this paper, I investigate how cultural differences affect the labor-market performance of immigrant workers in Germany. I document a negative relationship between hourly wages and the cultural distance ... [more ▼]

In this paper, I investigate how cultural differences affect the labor-market performance of immigrant workers in Germany. I document a negative relationship between hourly wages and the cultural distance between immigrants' countries of origin and Germany. This result is robust across the three main indicators used in the gravity literature: linguistic, religious, and genetic distances. This cultural wage penalty disappears after five to ten years spent in Germany. Controlling for language proficiency as well as for selective in- and out-migration, these results highlight the cultural integration of immigrant workers. I finally provide evidence suggesting that lower wage progression may be explained by fewer job-to-job transitions. [less ▲]

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See detailExplaining Defect Detection with Saliency Maps
Lorentz, Joe UL; Hartmann, Thomas; Moawad, Assaad et al

E-print/Working paper (2021)

The rising quality and throughput demands of the manufacturing domain require flexible, accurate and explainable computer-vision solutions for defect detection. Deep Neural Networks (DNNs) reach state-of ... [more ▼]

The rising quality and throughput demands of the manufacturing domain require flexible, accurate and explainable computer-vision solutions for defect detection. Deep Neural Networks (DNNs) reach state-of-the-art performance on various computer-vision tasks but wide-spread application in the industrial domain is blocked by the lacking explainability of DNN decisions. A promising, human-readable solution is given by saliency maps, heatmaps highlighting the image areas that influence the classifier’s decision. This work evaluates a selection of saliency methods in the area of industrial quality assurance. To this end we propose the distance pointing game, a new metric to quantify the meaningfulness of saliency maps for defect detection. We provide steps to prepare a publicly available dataset on defective steel plates for the proposed metric. Additionally, the computational complexity is investigated to determine which methods could be integrated on industrial edge devices. Our results show that DeepLift, GradCAM and GradCAM++ outperform the alternatives while the computational cost is feasible for real time applications even on edge devices. This indicates that the respective methods could be used as an additional, autonomous post-classification step to explain decisions taken by intelligent quality assurance systems. [less ▲]

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See detailThe Hidden Lattice Problem
Notarnicola, Luca UL; Wiese, Gabor UL

E-print/Working paper (2021)

We consider the problem of revealing a small hidden lattice from the knowledge of a low-rank sublattice modulo a given sufficiently large integer -- the {\em Hidden Lattice Problem}. A central motivation ... [more ▼]

We consider the problem of revealing a small hidden lattice from the knowledge of a low-rank sublattice modulo a given sufficiently large integer -- the {\em Hidden Lattice Problem}. A central motivation of study for this problem is the Hidden Subset Sum Problem, whose hardness is essentially determined by that of the hidden lattice problem. We describe and compare two algorithms for the hidden lattice problem: we first adapt the algorithm by Nguyen and Stern for the hidden subset sum problem, based on orthogonal lattices, and propose a new variant, which we explain to be related by duality in lattice theory. Following heuristic, rigorous and practical analyses, we find that our new algorithm brings some advantages as well as a competitive alternative for algorithms for problems with cryptographic interest, such as Approximate Common Divisor Problems, and the Hidden Subset Sum Problem. Finally, we study variations of the problem and highlight its relevance to cryptanalysis. [less ▲]

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Peer Reviewed
See detailEnvironmental Culture and Economic Complexity
Zanaj, Skerdilajda UL

E-print/Working paper (2021)

Detailed reference viewed: 229 (41 UL)
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See detailThe Long-Term Effect of Research Grants on the Scientific Output of University Professors
Hussinger, Katrin UL; Carvalho, J.N.

E-print/Working paper (2021)

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See detailRobust Estimation in Finite Mixture Models
Lecestre, Alexandre UL

E-print/Working paper (2021)

Detailed reference viewed: 191 (41 UL)
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Peer Reviewed
See detailGenetic Diversity and Performance: Evidence From Football Data
Zanaj, Skerdilajda UL; Beine, Michel UL; Peracchi, Silvia UL

E-print/Working paper (2021)

Detailed reference viewed: 192 (23 UL)
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See detailLes reliques des "martyrs de Gorcum" à Bruxelles
Weis, Monique UL; Houssiau, Jean

E-print/Working paper (2021)

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See detailThe role of score and information bias in panel data likelihoods
Schumann, Martin; Severini, Thomas A.; Tripathi, Gautam UL

E-print/Working paper (2021)

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See detailRedefining resilience: Integrative review and development of an assessment tool
Mantin, Binyamin UL

E-print/Working paper (2021)

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See detailIndeterminacies and models of homotopy limits
Govzmann, Alisa UL; Pistalo, Damjan UL; Poncin, Norbert UL

E-print/Working paper (2021)

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See detailFrom Centralized to Decentralized Finance: The Issue of “Fake-DeFi”
Zetzsche, Dirk Andreas UL; Anker-Sorensen, Linn

E-print/Working paper (2021)

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See detailThe EU Sustainable Finance Framework in Light of International Standards
Zetzsche, Dirk Andreas UL; Bodellini, Marco UL; Consiglio, Roberta

E-print/Working paper (2021)

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See detailStrategic Behavior in a Serial Newsvendor Setting
Perez Becker, Nicole UL; Mantin, Binyamin UL; Arts, Joachim UL

E-print/Working paper (2021)

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See detailA Principles-based Approach to the Governance of BigFintechs
Zetzsche, Dirk Andreas UL; Arner, Douglas; Buckley, Ross et al

E-print/Working paper (2021)

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Peer Reviewed
See detailTax competition and phantom FDI
Zanaj, Skerdilajda UL

E-print/Working paper (2021)

Detailed reference viewed: 296 (43 UL)
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See detailPost-Quantum Secure LFE for L/poly with Smaller Parameters
Naccache, David; Rosie, Razvan UL; Spignoli, Lorenzo UL

E-print/Working paper (2021)

Detailed reference viewed: 169 (7 UL)
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See detailAdversarial Robustness in Multi-Task Learning: Promises and Illusions
Ghamizi, Salah UL; Cordy, Maxime UL; Papadakis, Mike UL et al

E-print/Working paper (2021)

Vulnerability to adversarial attacks is a well-known weakness of Deep Neural networks. While most of the studies focus on single-task neural networks with computer vision datasets, very little research ... [more ▼]

Vulnerability to adversarial attacks is a well-known weakness of Deep Neural networks. While most of the studies focus on single-task neural networks with computer vision datasets, very little research has considered complex multi-task models that are common in real applications. In this paper, we evaluate the design choices that impact the robustness of multi-task deep learning networks. We provide evidence that blindly adding auxiliary tasks, or weighing the tasks provides a false sense of robustness. Thereby, we tone down the claim made by previous research and study the different factors which may affect robustness. In particular, we show that the choice of the task to incorporate in the loss function are important factors that can be leveraged to yield more robust models. [less ▲]

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See detailPROJECT WARLUX Ambiguities in biographies of Luxembourgish conscripts during and after WWII
Janz, Nina UL

E-print/Working paper (2021)

More than 10,000 Luxembourgish soldiers and recruits and an unknown number of Luxembourgish men and women wore German uniforms during WWII in armed forces and civil organisations, such as the Wehrmacht ... [more ▼]

More than 10,000 Luxembourgish soldiers and recruits and an unknown number of Luxembourgish men and women wore German uniforms during WWII in armed forces and civil organisations, such as the Wehrmacht, Waffen-SS, armed police forces and the Reichsarbeitsdienst (RAD). The "WARLUX" project, based at the University of Luxembourg in the Luxembourg Centre for Contemporary and Digital History (C2DH), intends to collect the biographical data of Luxembourgers who were drafted into the German Army and the Labour Service. Around 3,000 young men and women are used in a case study to research their biographies and individual stories during the war, highlight different approaches to researching World War II, and show different résumés and personal experiences during this period. WARLUX aims to review the categories that have tended to be used in the national history discourse. For these women and men were called different like "forced recruit", "volunteer", "réfractaire" and "déserteur" were used, next to mentions of "Mort la patrie" for whom who died in German uniform. Are these terms appropriate to describe the experiences of these individuals, or do they need to be elucidated and challenged? Who were the people behind these abstract terms? What were their individual experiences, stories, reactions, choices, contradictions and survival strategies during and after World War II (Tames 2016)? The term "forced recruit" has come to suggest the general victim status of all conscripted Luxembourgish soldiers. In this content between the dualism of the official narrative and the historiography of the last decades, the project WARLUX wants to apply another concept: "situative opportunism", to question the cumulative heroism and the power of collective forms of decision-making in "forced environments", like the enrolment of young women and men (Fickers/Brüll, 2019). Following the biographical approach by analysing documents and personal views (letters, diaries), Andreas Fickers and Christoph Brüll (2019) use the term "situative opportunism" to emphasise the link between biographical research and sociological decision theory. Based on Schimank (2005), the authors state that every historical actor has multiple options in a complex decision-making process; these decisions are not necessarily egoist, neither the result of external constraints, but grounded in a situational logic of doing what seems most suitable in this very moment. The project is still in the initial phase but will soon deepen the analysis of the biographies of the individuals using the term "situational opportunism". With the application for the conference, the project team would like to discuss other approaches and start an exchange about other/opposite concepts. [less ▲]

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See detailCommon pool resource management and risk perceptions
Mavi, Can Askan UL; Quérou, Nicolas

E-print/Working paper (2020)

Motivated by recent discussions about the issue of risk perceptions for climate change related events, we introduce a non-cooperative game setting where agents manage a common pool resource under a ... [more ▼]

Motivated by recent discussions about the issue of risk perceptions for climate change related events, we introduce a non-cooperative game setting where agents manage a common pool resource under a potential risk, and agents exhibit different risk perception biases. Focusing on the effect of the polarization level and other population features, we show that the type of bias (overestimation versus underestimation biases) and the resource quality level before and after the occurrence of the shift have first-order importance on the qualitative nature of behavioral adjustments and on the pattern of resource conservation. When there are non-uniform biases within the population, the intra-group structure of the population qualitatively affects the degree of resource conservation. Moreover, unbiased agents may react in nonmonotone ways to changes in the polarization level when faced with agents exhibiting different types of bias. The size of the unbiased agents’ sub-population does not qualitatively affect how an increase in the polarization level impacts individual behavioral adjustments, even though it affects the magnitude of this change. Finally, it is shown how perception biases affect the comparison between centralized and decentralized management. [less ▲]

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See detailTHIS TIME IS REALLY DIFFERENT: FLIGHT-TO-SAFETY AND THE COVID-19 CRISIS
Löwen, Celina; Kchouri, Bilal UL; Lehnert, Thorsten UL

E-print/Working paper (2020)

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See detailLinear Z2n-Manifolds and Linear Actions
Bruce, Andrew UL; Ibarguengoytia, Eduardo UL; Poncin, Norbert UL

E-print/Working paper (2020)

Detailed reference viewed: 94 (13 UL)
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See detailRobust Estimation of a Regression Function in Exponential Families
Baraud, Yannick UL; Chen, Juntong UL

E-print/Working paper (2020)

Detailed reference viewed: 238 (63 UL)
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See detailThe Luxembourg COVID-Kids questionnaire
Kirsch, Claudine UL; Engel de Abreu, Pascale UL; Neumann, Sascha UL

E-print/Working paper (2020)

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See detailDer Arbeitsmarkt der Sozialen Arbeit 2019 = Le marché de l'emploi du secteur social en 2019
Böwen, Petra UL; Flammang, Manou Laure UL

E-print/Working paper (2020)

This newsletter describes the job market in the social work sector in Luxembourg in 2019. The data are derived from an ongoing research project by the PraxisBüro of the University of Luxembourg. The ... [more ▼]

This newsletter describes the job market in the social work sector in Luxembourg in 2019. The data are derived from an ongoing research project by the PraxisBüro of the University of Luxembourg. The newsletter presents a selection of statistics concerning for example the most sought after qualification levels, the distribution of practice fields, the distribution of job offers on public, municipal, privat an non-governmental organisations an the documented gab between the demand of social workers with a Bachelor diploma and the number of Bachelor diplomas issued in Luxembourg [less ▲]

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See detailDynamics of Achievement inequalities: the role of performance and choice in Chile
Ceron, Francisco UL; Bol, Thijs; Van de Werfhorst, Herman

E-print/Working paper (2020)

Research on education inequalities has long-established the relationship between the social composition of of schools and achievement levels. However, the empirical study of the social processes in ... [more ▼]

Research on education inequalities has long-established the relationship between the social composition of of schools and achievement levels. However, the empirical study of the social processes in choosing schools and their potential effects on achievement inequalities has often been neglected. This article investigates the extent to which such social processes, related to parents’ educational preferences and expectations, influence the development of students’ achievement inequalities throughout their schooling career, through shaping school communities, as a channel of transmission of socioeconomic inequality. Using longitudinal census data from Chile, which allows us to observe students’ achievements between the 4th and 10th grades, we find support for the claim that the development of achievement inequalities operate partly through well-off parents’ educational preferences and expectations. Moreover, these preferences and beliefs explain most of the social composition effect of schools on achievement inequalities. We conclude that choice processes should be considered as an integral part of theories aimed to explain achievement inequalities as a dynamic process. [less ▲]

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See detailThe Lehman Sisters Claim
Lehnert, Thorsten UL

E-print/Working paper (2020)

I evaluate Christine Lagarde´s claim that more female leaders can be associated with more prudence, and less of the risky decision-making that had provoked the crisis. Indeed, the proportion of women who ... [more ▼]

I evaluate Christine Lagarde´s claim that more female leaders can be associated with more prudence, and less of the risky decision-making that had provoked the crisis. Indeed, the proportion of women who are employed in decision-making and management roles in governments, large enterprises and institutions varies substantially across European countries and is oftentimes below 30%. Research suggests that in addition to biological differences, men and women show morphological dissimilarities in specific brain regions, which explain the observed differences in behavior. As a result, female decision makers tend to be more risk averse, better suited to carefully analyze a problem, superior in multitasking and better in creating solutions that work for a group. Not surprisingly, firms with more female decision makers tend to outperform their peers in terms of productivity, profitability and stock performance while taking fewer risks. In this paper, I aim to explore the effect of female decision making on aggregate equity returns. Relying on an equilibrium asset-pricing model in an economy under jump diffusion, I decompose the moments of the returns of European stock market indices into a diffusive (systematic) risk and an (idiosyncratic) extreme event risk part. For a balanced panel of European countries, I find empirical evidence for a Lehman sisters’ effect: female decision making is an important determinant of (idiosyncratic) extreme event risk. As a result, stock markets in countries with more female decision makers are characterized by higher risk aversion, lower volatility and more positive return asymmetry, primarily driven by extreme event risk, e.g. the lower frequency of negative jumps. Results are robust to the inclusion of various controls for other country- or market-specific characteristics. [less ▲]

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See detailRetail Investors' Flight-From-Safety and the Skewness Risk Premium
Lehnert, Thorsten UL

E-print/Working paper (2020)

Detailed reference viewed: 117 (6 UL)
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See detailDeniable encryption, authentication, and key exchange
Ostrev, Dimiter UL

E-print/Working paper (2020)

We present some foundational ideas related to deniable encryption, message authentication, and key exchange in classical cryptography. We give detailed proofs of results that were previously only sketched ... [more ▼]

We present some foundational ideas related to deniable encryption, message authentication, and key exchange in classical cryptography. We give detailed proofs of results that were previously only sketched in the literature. In some cases, we reach the same conclusions as in previous papers; in other cases, the focus on rigorous proofs leads us to different formulations of the results. [less ▲]

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See detailFiscal effects of migrants in Europe: a quantile regression approach
Joxhe, Majlinda UL; Zanaj, Skerdilajda UL; Scaramozzino, Pasquale

E-print/Working paper (2020)

In this paper, we explore the fiscal impact of immigrants in Europe applying a quantile regression approach to data from the European Survey on Living Conditions (EU-SILC) for the period 2007-2015. Our ... [more ▼]

In this paper, we explore the fiscal impact of immigrants in Europe applying a quantile regression approach to data from the European Survey on Living Conditions (EU-SILC) for the period 2007-2015. Our estimations show that not only on average but also in almost all income quantiles, the fiscal position of both European and non-European migrants is not significantly different from that of native citizens. Furthermore, non-EU migrants are net contributors as compared to the corresponding native citizens in the Netherlands and Belgium for various quantiles. Lastly, we examine the link between migrants’ fiscal position and the fiscal perception of native European citizens measured using ESS data. We find a conflicting relationship: countries where migrants are perceived negatively are instead countries where they are net fiscal contributors and vice versa. [less ▲]

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See detailOptimized Collision Search for STARK-Friendly Hash Challenge Candidates
Udovenko, Aleksei UL

E-print/Working paper (2020)

In this note, we report several solutions to the STARK-Friendly Hash Challenge: a competition with the goal of finding collisions for several hash functions designed specifically for zero-knowledge proofs ... [more ▼]

In this note, we report several solutions to the STARK-Friendly Hash Challenge: a competition with the goal of finding collisions for several hash functions designed specifically for zero-knowledge proofs (ZKP) and multiparty computations (MPC). We managed to find collisions for 3 instances of 91-bit hash functions. The method used is the classic parallel collision search with distinguished points from van Oorshot and Wiener (1994). As this is a general attack on hash functions, it does not exhibit any particular weakness of the chosen hash functions. The crucial part is to optimize the implementations to make the attack cost realistic, and we describe several arithmetic tricks. [less ▲]

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See detailThe signature method : a new tool enhancing time series clustering
Clausel, Marianne; Lejay, Antoine; Terraza, Virginie UL

E-print/Working paper (2020)

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See detailEstimating the number of infected persons
Baraud, Yannick UL; Nourdin, Ivan UL; Peccati, Giovanni UL

E-print/Working paper (2020)

The aim of this paper is to provide a confidence interval on the number of infected persons by COVID-19 within the population from the number of deaths reported in the hospitals and the mortality rate ... [more ▼]

The aim of this paper is to provide a confidence interval on the number of infected persons by COVID-19 within the population from the number of deaths reported in the hospitals and the mortality rate (that is assumed to be known). [less ▲]

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See detailSouth Africa’s incomplete transition towards socio-economic justice: A case study on inequality and populism
Owiso, Owiso UL; Boshoff, Elsabé

E-print/Working paper (2020)

South Africa is currently one of the world’s most unequal countries, with massive income inequality, millions of people living in poverty without access to basic services and amenities, unemployment rates ... [more ▼]

South Africa is currently one of the world’s most unequal countries, with massive income inequality, millions of people living in poverty without access to basic services and amenities, unemployment rates consistently above 20% and the top 10% of the population receiving two thirds of the total income. Government economic policies on poverty reduction in the decades since the advent of democracy in South Africa in 1994 have been unable to eradicate the extreme racialised inequality which was the basis of the 342 years of colonialism and apartheid which were characterised by systematic dispossession and socio-economic marginalisation of South Africa’s majority Black population and the systematic privileging of the minority White population. While this history is not the primary focus of this paper, it nonetheless provides useful context. The paper’s primary focus is on the more recent normative and legal challenges of post-1994 South Africa that have resulted in further entrenching socio-economic inequality and contributing to the rise of populism. In this paper we argue that the dire living conditions of a large proportion of the population and disillusionment with the State’s ability to deliver on its promises in this regard, along with the poor implementation of social and economic rights have led to the development of a populist culture in South African politics. [less ▲]

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See detailOn the structure of symmetric $n$-ary bands
Devillet, Jimmy UL; Mathonet, Pierre

E-print/Working paper (2020)

We study the class of symmetric $n$-ary bands. These are $n$-ary semigroups $(X,F)$ such that $F$ is invariant under the action of permutations and idempotent, i.e., satisfies $F(x,\ldots,x)=x$ for all $x ... [more ▼]

We study the class of symmetric $n$-ary bands. These are $n$-ary semigroups $(X,F)$ such that $F$ is invariant under the action of permutations and idempotent, i.e., satisfies $F(x,\ldots,x)=x$ for all $x\in X$. We first provide a structure theorem for these symmetric $n$-ary bands that extends the classical (strong) semilattice decomposition of certain classes of bands. We introduce the concept of strong $n$-ary semilattice of $n$-ary semigroups and we show that the symmetric $n$-ary bands are exactly the strong $n$-ary semilattices of $n$-ary extensions of Abelian groups whose exponents divide $n-1$. Finally, we use the structure theorem to obtain necessary and sufficient conditions for a symmetric $n$-ary band to be reducible to a semigroup. [less ▲]

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See detailLegal Readiness for Climate Finance: The case of Bangladesh towards a transition to climate resilience
Alexandraki, Chrysa UL

E-print/Working paper (2020)

Even though the Paris Agreement posits the need to align overall financial flows with low-carbon and climate-resilient development in the heart of its objectives, developing countries face ample ... [more ▼]

Even though the Paris Agreement posits the need to align overall financial flows with low-carbon and climate-resilient development in the heart of its objectives, developing countries face ample constraints in mitigating and adapting to climate change, while concomitantly embarking on reconciling the curbing of climate change with development concerns. Climate finance constitutes an enabling means not only for assisting developing countries in building capacities and enabling environments to address climate change in compliance with their commitments under the Paris Agreement, but most importantly for ushering a long-term development shift towards sustainability. This article furthers the discourse on what it means to be ‘legally ready’ for climate finance. It argues that legal reforms present a means to overcome legal barriers undermining climate finance effectiveness in developing countries, aimed at mainstreaming climate change considerations across all sectors and national policies, stimulating climate-related flows from all sources of finance, and instituting a paradigm shift towards climate-resilient development. First, it elaborates on the role of law in building climate finance readiness, the key legal barriers encountered in developing countries, and the main legal approaches and regulatory tools likely to enhance the four main capacities required to be ready for climate finance. Second, it illustrates the laws and policies currently implemented in Bangladesh concerning the country’s readiness for climate finance. The article concludes premised on the case study of Bangladesh that legal reforms are essential in developing countries, in order to ensure long-term climate finance effectiveness steering transformative changes. [less ▲]

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See detailApproximation of Riemannian measures by Stein’s method
Thompson, James UL

E-print/Working paper (2020)

Detailed reference viewed: 88 (2 UL)
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See detailIdentifiability of Finite Mixture Models with underlying Normal Distribution
Noel, Cédric; Schiltz, Jang UL

E-print/Working paper (2020)

In this paper, we show under which conditions generalized finite mixture with underlying normal distribution are identifiable in the sense that a given dataset leads to a uniquely determined set of model ... [more ▼]

In this paper, we show under which conditions generalized finite mixture with underlying normal distribution are identifiable in the sense that a given dataset leads to a uniquely determined set of model parameter estimations up to a permuta-tion of the clusters. [less ▲]

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Peer Reviewed
See detailProfit taxation and royalties: evidence from gold mines in Sub-Saharan Africa
Bertinelli, Luisito UL; Bourgain, Arnaud UL; Zanaj, Skerdilajda UL

E-print/Working paper (2019)

In this paper, we analyze theoretically and empirically the effects of tax changes on firms’ profits in extractive industries. In the theoretical part, we assume a country that levies a profit tax and a ... [more ▼]

In this paper, we analyze theoretically and empirically the effects of tax changes on firms’ profits in extractive industries. In the theoretical part, we assume a country that levies a profit tax and a royalty on the profits of extractive firms to maximize its tax revenues. The mining companies may reduce their taxable income by cost manipulation. By analyzing the optimal choice of the government and of the firms, we first establish the optimal tax policy and then we investigate the impact of the optimal fiscal policy on firms’ profits. In the empirical part of the paper, we estimate the effect of the profit tax and royalty on the extracting firms’ profit in African countries during the period spanning from 2007 to 2018. We use the Mining Intelligence database to constitute a panel of annual individual data from a database of 363 gold mines located in 21 Sub-Saharan countries. We obtain an inverse relationship between the tax rate change of the two tax instruments and the profit of the firms. [less ▲]

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See detailDer Arbeitsmarkt der Sozialen Arbeit 2018 = Le marché de l'emploi du secteur social en 2018
Flammang, Manou Laure UL; Böwen, Petra UL

E-print/Working paper (2019)

This newsletter describes the job market in the social work sector in Luxembourg in 2018. The data are derived from an ongoing research project by the "PraxisBüro" of the University of Luxembourg. The ... [more ▼]

This newsletter describes the job market in the social work sector in Luxembourg in 2018. The data are derived from an ongoing research project by the "PraxisBüro" of the University of Luxembourg. The newsletter presents a selection of statistics concerning for example the most sought after qualification levels, the distribution of practice fields, the distribution of job offers in public, municipal, private and non-governmental organisations and the documented gap between the demand of social workers with a Bachelor diploma and the number of Bachelor diplomas issued in Luxembourg. [less ▲]

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See detailThe dual volume of quasi-Fuchsian manifolds and the Weil-Petersson distance
Mazzoli, Filippo UL

E-print/Working paper (2019)

Making use of the dual Bonahon-Schläfli formula, we prove that the dual volume of the convex core of a quasi-Fuchsian manifold M is bounded by an explicit constant, depending only on the topology of M ... [more ▼]

Making use of the dual Bonahon-Schläfli formula, we prove that the dual volume of the convex core of a quasi-Fuchsian manifold M is bounded by an explicit constant, depending only on the topology of M, times the Weil-Petersson distance between the hyperbolic structures on the upper and lower boundary components of the convex core of M. [less ▲]

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See detailFuturistic Project Becoming a Reality: Self-Driving Cars in Luxembourg
Vukovich, Lilla UL; Vysotskaya, Volha UL

E-print/Working paper (2019)

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See detailWHY IS THE MARKET SKEWNESS-RETURN RELATIONSHIP NEGATIVE?
Lehnert, Thorsten UL

E-print/Working paper (2019)

Detailed reference viewed: 99 (3 UL)
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Peer Reviewed
See detailInexact Block Coordinate Descent Algorithms for Nonsmooth Nonconvex Optimization
Yang, Yang UL; Pesavento, Marius; Luo, Zhi-Quan et al

E-print/Working paper (2019)

In this paper, we propose an inexact block coordinate descent algorithm for large-scale nonsmooth nonconvex optimization problems. At each iteration, a particular block variable is selected and updated by ... [more ▼]

In this paper, we propose an inexact block coordinate descent algorithm for large-scale nonsmooth nonconvex optimization problems. At each iteration, a particular block variable is selected and updated by solving the original optimization problem with respect to that block variable inexactly. More precisely, a local approximation of the original optimization problem is solved. The proposed algorithm has several attractive features, namely, i) high flexibility, as the approximation function only needs to be strictly convex and it does not have to be a global upper bound of the original function; ii) fast convergence, as the approximation function can be designed to exploit the problem structure at hand and the stepsize is calculated by the line search; iii) low complexity, as the approximation subproblems are much easier to solve and the line search scheme is carried out over a properly constructed differentiable function; iv) guaranteed convergence to a stationary point, even when the objective function does not have a Lipschitz continuous gradient. Interestingly, when the approximation subproblem is solved by a descent algorithm, convergence to a stationary point is still guaranteed even if the approximation subproblem is solved inexactly by terminating the descent algorithm after a finite number of iterations. These features make the proposed algorithm suitable for large-scale problems where the dimension exceeds the memory and/or the processing capability of the existing hardware. These features are also illustrated by several applications in signal processing and machine learning, for instance, network anomaly detection and phase retrieval. [less ▲]

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See detailTo be or not to be: How the Luxembourgish government is preparing for Brexit
Vysotskaya, Volha UL; Vukovich, Lilla UL; Bissinger, Jutta UL et al

E-print/Working paper (2019)

This article summarizes the potential impact of BREXIT on Luxembourg (as seen by April 2019).

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See detailFear and Euphoria
Lehnert, Thorsten UL

E-print/Working paper (2019)

Detailed reference viewed: 73 (1 UL)
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See detailCorporate Governance and Skewness in Stock Returns
Berglund, Tom; Lehnert, Thorsten UL; Rolle, Gudrun

E-print/Working paper (2019)

This paper analyzes the relationship between corporate governance and idiosyncratic skewness of stock returns. We test this hypothesis by analyzing the impact of external as well as internal governance ... [more ▼]

This paper analyzes the relationship between corporate governance and idiosyncratic skewness of stock returns. We test this hypothesis by analyzing the impact of external as well as internal governance provisions, and are thus able to provide an overall understanding of the relationship between governance and firm-specific return asymmetries. Our results show that better governance leads to a reduction in idiosyncratic skewness in relatively non-competitive industries. In relatively competitive industries, governance has less to no impact on firm-specific return skewness. Furthermore, an overall increase in transparency, quality and disclosure of information, proxied through the Sarbanes Oxley Act, reduces relative idiosyncratic skewness. Our findings can be regarded as detrimental for shareholders, who have a preference for positive idiosyncratic skewness. The evidence contributes to a debate, which suggests that – at the end of the day – an act like Sarbanes-Oxley, which was intended to protect shareholders from accounting errors and frauds and to improve the accuracy of corporate disclosures, comes at the expenses of shareholders. The reduction of idiosyncratic skewness through better governance collides with shareholder’s preference for idiosyncratic and positively skewed stock returns, which present a lottery like upside option of monetary gains and value creation through the right tail. This side effect of governance is also in line with the literature that highlights potential costs of corporate governance. [less ▲]

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See detailA System and Method for Monitoring Controlling and Troubleshooting of Abrasive Waterjet Cutting Apparatus
Copertaro, Edoardo UL

E-print/Working paper (2019)

The invention consists of a system and method for monitoring, controlling and troubleshooting of Abrasive Waterjet Cutting machinery. More in detail, the method exploits a network of sensors for ... [more ▼]

The invention consists of a system and method for monitoring, controlling and troubleshooting of Abrasive Waterjet Cutting machinery. More in detail, the method exploits a network of sensors for continuously monitor its vibroacoustic emission pattern. Relevant features are extracted from the data using an iterative processing method. Deviations from a benchmark are interpreted based on model training then used for automatic control and troubleshooting. The expected outcome is an improvement of waterjet automation and robustness to the excellence of Industry 4.0 with a consequent impact on both its cost effectiveness and the provided quality assurance. [less ▲]

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See detailSocial division in the market: conspicous consumption with nationalist feelings
Zanaj, Skerdilajda UL

E-print/Working paper (2019)

In this paper, we explore the effects of conspicuous goods as a means of social division between native citizens and migrants. We push forward the hypothesis that choosing a particular good can confer a ... [more ▼]

In this paper, we explore the effects of conspicuous goods as a means of social division between native citizens and migrants. We push forward the hypothesis that choosing a particular good can confer a sense of place. We introduce this idea in an international vertical differentiation market with two variants and two social groups: migrants and natives. Natives are narrow-minded since they attribute a positive social value to the variant that complies with their own consumption culture. Migrants are open-minded. When consumers belonging to different groups meet, they exchange information about their consumption habits and consumption well-being that reveals their consumption culture: narrow-minded versus open-minded. Consequently, after meeting, some consumers may change beliefs (narrow-minded to open-minded or vice versa) and consumption choices. Using a dynamic model, we fully elucidate the steady-state equilibrium and highlight the impact of nationalism on migrant integration. [less ▲]

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See detailAn introduction to the theory of unconditionally secure message authentication using the constructive cryptography framework
Ostrev, Dimiter UL

E-print/Working paper (2019)

We provide an introduction to certain ideas from the theory of unconditionally secure message authentication. We explain the notions of impersonation and substitution attacks, and explain how protection ... [more ▼]

We provide an introduction to certain ideas from the theory of unconditionally secure message authentication. We explain the notions of impersonation and substitution attacks, and explain how protection against these two types of attack implies composable, information theoretic security. We explain the relation of authentication protocols to universal hashing. We give both probabilistic and explicit constructions proving the existence of one way authentication protocols using a short secret key and we prove matching lower bounds on the required secret key size. Then, we turn attention to interactive authentication protocols. We explain the message size reduction technique used by Gemmell and Naor and later Naor, Segev and Smith, and how it leads to protocols with secret key size independent of the message length. We also prove a matching lower bound on the secret key entropy. We generalize the lower bound proof of Naor, Segev and Smith and remove the assumption that the message is revealed in the first flow of the protocol. [less ▲]

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See detailConsumption home bias and ethnocentrism: an international duopoly
Zanaj, Skerdilajda UL

E-print/Working paper (2019)

We define a model with two countries and two vertically differentiated goods, a high and a low-quality variant, and heterogenous consumers with respect to their willingness to pay for quality. Consumers ... [more ▼]

We define a model with two countries and two vertically differentiated goods, a high and a low-quality variant, and heterogenous consumers with respect to their willingness to pay for quality. Consumers in one country are ethnocentric in consumption. They thrive additional satisfaction when consuming a domestic good rather than a foreign one since only the former can satisfy their sense of place. We investigate the role of trade costs and ethnocentric attitude in shaping the equilibrium configuration of the international duopoly. [less ▲]

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See detailKrichever-Novivkov type algebras. A general review and the genus zero case
Schlichenmaier, Martin UL

E-print/Working paper (2019)

In the first part of this survey we recall the definition and some of the constructions related to Krichever--Novikov type algebras. Krichever and Novikov introduced them for higher genus Riemann surfaces ... [more ▼]

In the first part of this survey we recall the definition and some of the constructions related to Krichever--Novikov type algebras. Krichever and Novikov introduced them for higher genus Riemann surfaces with two marked points in generalization of the classical algebras of Conformal Field Theory. Schlichenmaier extended the theory to the multi-point situation and even to a larger class of algebras. The almost-gradedness of the algebras and the classification of almost-graded central extensions play an important role in the theory and in applications. In the second part we specialize the construction to the genus zero multi-point case. This yields beside instructive examples also additional results. In particular, we construct universal central extensions for the involved algebras, which are vector field algebras, differential operator algebras, current algebras and Lie superalgebras. We point out that the recently (re-)discussed $N$-Virasoro algebras are nothing else as multi-point genus zero Krichever-Novikov type algebras. The survey closes with structure equations and central extensions for the three-point case. [less ▲]

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See detailErster Forschungsbericht zur Weiterentwicklung der „Enquête concernant la qualité de vie et la motivation au travail“.
Sischka, Philipp UL; Fernandez de Henestrosa, Martha UL; Steffgen, Georges UL

E-print/Working paper (2019)

Das Ministère de la Fonction publique et de la Réforme administrative hat 2017 eine Befragung mit dem Titel “Enquête concernant la qualité de vie et la motivation au travail” unter den Mitarbeitern des ... [more ▼]

Das Ministère de la Fonction publique et de la Réforme administrative hat 2017 eine Befragung mit dem Titel “Enquête concernant la qualité de vie et la motivation au travail” unter den Mitarbeitern des öffentlichen Dienstes durchgeführt. Die Universität Luxembourg wurde damit betraut, die psychometrische Qualität des Fragebogens zu prüfen, die Zusammenhänge zwischen den Gruppenvariablen zu untersuchen, die gruppenbezogene Vergleiche vorzulegen, die Befunde mit mit denen anderer Studien zu vergleichen sowie Handlungshinweise zur Optimierung der Arbeitsqualitàt vorzulegen (siehe Convention de recherche entre l‘Université du Luxembourg et le Minsitère de la Fonction Publique et de la Réforme administrative du 24. mai 2018). Entsprechend der Vorgaben der Konvention werden in dem vorliegenden ersten Bericht, die Befunde a) zu der psychometrischen Testung der Güte des aktuellen Erhebungsinstruments (Punkt 2.1.1 der Konvention), b) zu den gruppenbezogenen Vergleiche (Punkt 2.1.3, Satz 1 der Konvention) sowie c) zu den Zusammenängen zwischen den Gruppenvariablen (Punkt 2.1.2 der Konvention) vorgelegt. In einem ersten Schritt erfolgt zunächst eine Beschreibung der Items mittels verteilungsbe-schreibender Maßzahlen und Balkendiagramme, wobei die Items auch auf fehlende Werte un-tersucht werden. Ergebnisse der inhaltlichen und psychometrischen Itemprüfung zeigen, dass der Fragebogen z.T. noch wichtige Entwicklungsfelder aufweist. In einem zweiten Schritt werden exploratorische Faktorenanalysen durchgeführt, um einen Überblick über die Faktorstruktur des Fragebogens zu erhalten. Die Faktoranalysen erfolgen bezogen auf die einzelnen Themenblöcke (Zufriedenheit, Motivation, Wohlbefinden, Arbeits-bedingungen). Auf Basis der identifizierten Faktorstruktur wurden geeignete Items aus den vier Bereichen zu 17 Skalen zusammengefasst. In einem dritten Schritt erfolgt eine Analyse der internen Konsistenz der neu gebildeten Skalen. Zudem werden die Inter-Korrelationen dieser Skalen vorgelegt. Befunde zeigen, dass die meisten Skalen akzeptable bis exzellente Reliabilitätskoeffizienten aufweisen. Allerdings lassen sich erhöhte Inter-Korrelationen zwischen einigen Skalen identifizieren, die auf eine vorliegende Redundanz der Skalen deuten. In einem vierten Schritt werden gruppenbezogene Vergleiche hinsichtlich Geschlecht, Alters-gruppen, Beschäftigungssituation, Jahre im öffentlichen Dienst, Gehaltsgruppen, Anzahl Zusammenfassung II zugeordneter Mitarbeiter sowie Länge des Arbeitswegs zu den neu gebildeten Skalen durchgeführt und die Befunde präsentiert. Beispielsweise zeigen Mitarbeiter mit den wenigsten Jahren im öffentlichen Dienst tendenziell günstigere Werte hinsichtlich der vier Themenblöcke auf. In einem fünften Schritt werden Regressionsanalysen durchgeführt, um Zusammenhänge zwischen den Gruppenvariablen, Arbeitsbedingungen und den einzelnen Themenblöcken zu veranschaulichen. Die Befunde verdeutlichen, dass Zufriedenheit, Motivation und Wohl-befinden mit verschiedenen Arbeitsbedingungen assoziiert sind. In einem abschließenden Schritt wird das gesamte Erhebungsinstrument zusammenfassend diskutiert und Empfehlungen bezüglich der weiteren Entwicklung des Fragebogens und der Skalen gegeben. [less ▲]

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