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See detailValue-Added Scores Show Limited Stability over Time in Primary School
Emslander, Valentin UL; Levy, Jessica; Scherer, Ronny et al

E-print/Working paper (2022)

Value-added (VA) models are used for accountability purposes and quantify the value a teacher or a school adds to their students’ achievement. If VA scores lack stability over time and vary across outcome ... [more ▼]

Value-added (VA) models are used for accountability purposes and quantify the value a teacher or a school adds to their students’ achievement. If VA scores lack stability over time and vary across outcome domains (e.g., mathematics and language learning), their use for high-stakes decision making is in question and could have detrimental real-life implications: teachers could lose their jobs, or a school might receive less funding. However, school-level stability over time and variation across domains have rarely been studied together. In the present study, we examined the stability of VA scores over time for mathematics and language learning, drawing on representative, large-scale, and longitudinal data from two cohorts of standardized achievement tests in Luxembourg (N = 7,016 students in 151 schools). We found that only 34-38% of the schools showed stable VA scores over time with moderate rank correlations of VA scores from 2017 to 2019 of r = .34 for mathematics and r = .37 for language learning. Although they showed insufficient stability over time for high- stakes decision making, school VA scores could be employed to identify teaching or school practices that are genuinely effective—especially in heterogeneous student populations. [less ▲]

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See detailWargames
Pause, Johannes UL

in Flintrop, Michael (Ed.) John Badham. Blick und Bewegung (2022)

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See detailUnlinkability of an Improved Key Agreement Protocol for EMV 2nd Gen Payments
Horne, Ross James UL; Mauw, Sjouke UL; Yurkov, Semen UL

Scientific Conference (2022, August 10)

To address known privacy problems with the EMV standard, EMVCo have proposed a Blinded Diffie-Hellman key establishment protocol, which is intended to be part of a future 2nd Gen EMV protocol. We point ... [more ▼]

To address known privacy problems with the EMV standard, EMVCo have proposed a Blinded Diffie-Hellman key establishment protocol, which is intended to be part of a future 2nd Gen EMV protocol. We point out that active attackers were not previously accounted for in the privacy requirements of this proposal protocol, and demonstrate that an active attacker can compromise unlinkability within a distance of 100cm. Here, we adopt a strong definition of unlinkability that does account for active attackers and propose an enhancement of the protocol proposed by EMVCo. We prove that our protocol does satisfy strong unlinkability, while preserving authentication. [less ▲]

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See detailQuantum machine learning corrects classical forcefields: Stretching DNA base pairs in explicit solvent
Berryman, Josh UL; Taghavi, Amirhossein UL; Mazur, Florian UL et al

in Journal of Chemical Physics (2022), 157(6),

In order to improve the accuracy of molecular dynamics simulations, classical forcefields are supplemented with a kernel-based machine learning method trained on quantum-mechanical fragment energies. As ... [more ▼]

In order to improve the accuracy of molecular dynamics simulations, classical forcefields are supplemented with a kernel-based machine learning method trained on quantum-mechanical fragment energies. As an example application, a potential-energy surface is generalized for a small DNA duplex, taking into account explicit solvation and long-range electron exchange–correlation effects. A long-standing problem in molecular science is that experimental studies of the structural and thermodynamic behavior of DNA under tension are not well confirmed by simulation; study of the potential energy vs extension taking into account a novel correction shows that leading classical DNA models have excessive stiffness with respect to stretching. This discrepancy is found to be common across multiple forcefields. The quantum correction is in qualitative agreement with the experimental thermodynamics for larger DNA double helices, providing a candidate explanation for the general and long-standing discrepancy between single molecule stretching experiments and classical calculations of DNA stretching. The new dataset of quantum calculations should facilitate multiple types of nucleic acid simulation, and the associated Kernel Modified Molecular Dynamics method (KMMD) is applicable to biomolecular simulations in general. KMMD is made available as part of the AMBER22 simulation software. [less ▲]

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See detailRényi Entropy in Statistical Mechanics
Fuentes, Jesús UL; Goncalves, Jorge UL

in Entropy (2022), 24(8), 1080

Rényi entropy was originally introduced in the field of information theory as a parametric relaxation of Shannon (in physics, Boltzmann–Gibbs) entropy. This has also fuelled different attempts to ... [more ▼]

Rényi entropy was originally introduced in the field of information theory as a parametric relaxation of Shannon (in physics, Boltzmann–Gibbs) entropy. This has also fuelled different attempts to generalise statistical mechanics, although mostly skipping the physical arguments behind this entropy and instead tending to introduce it artificially. However, as we will show, modifications to the theory of statistical mechanics are needless to see how Rényi entropy automatically arises as the average rate of change of free energy over an ensemble at different temperatures. Moreover, this notion is extended by considering distributions for isospectral, non-isothermal processes, resulting in relative versions of free energy, in which the Kullback–Leibler divergence or the relative version of Rényi entropy appear within the structure of the corrections to free energy. These generalisa- tions of free energy recover the ordinary thermodynamic potential whenever isothermal processes are considered. [less ▲]

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See detailRace And Gender Inequalities In Citations And Research Topics In US
Kozlowski, Diego UL; Monroe-White, Thema

Article for general public (2022)

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See detailQuality Assessment in Meta-Analyses (QuAMA)
Scherer, Ronny; Emslander, Valentin UL

Report (2022)

This project develops methods and procedures to (a) quantify the quality of primary studies in meta-analyses; and (b) account for primary-study quality in moderator analyses. As part of the project, we ... [more ▼]

This project develops methods and procedures to (a) quantify the quality of primary studies in meta-analyses; and (b) account for primary-study quality in moderator analyses. As part of the project, we develop an analytic procedure to create study quality indicators and incorporate them in the meta-analysis. We will present this procedure in a step-by-step tutorial with illustrative examples. [less ▲]

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See detailIntegration of external biomass reactions into existing metabolic models
Moscardo Garcia, Maria UL; Pires Pacheco, Maria Irene UL; Sauter, Thomas UL

E-print/Working paper (2022)

Currently, seven biomass objective functions have been defined in human metabolic reconstructions. The integration of published biomass reactions into alternative models can contribute to the prediction ... [more ▼]

Currently, seven biomass objective functions have been defined in human metabolic reconstructions. The integration of published biomass reactions into alternative models can contribute to the prediction power of the model. Thus, in this work, we present a workflow to integrate reactions and biomass functions originating from several genome-scale reconstructions into models other than their home models. Additionally, a benchmark to identify the biomass that confers the highest prediction accuracy in terms of gene essentiality and growth predictions is provided. [less ▲]

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See detailProbabilistic Deep Learning for Real-Time Large Deformation Simulations
Deshpande, Saurabh UL; Lengiewicz, Jakub UL; Bordas, Stéphane UL

in Computer Methods in Applied Mechanics and Engineering (2022), 398(0045-7825), 115307

For many novel applications, such as patient-specific computer-aided surgery, conventional solution techniques of the underlying nonlinear problems are usually computationally too expensive and are ... [more ▼]

For many novel applications, such as patient-specific computer-aided surgery, conventional solution techniques of the underlying nonlinear problems are usually computationally too expensive and are lacking information about how certain can we be about their predictions. In the present work, we propose a highly efficient deep-learning surrogate framework that is able to accurately predict the response of bodies undergoing large deformations in real-time. The surrogate model has a convolutional neural network architecture, called U-Net, which is trained with force–displacement data obtained with the finite element method. We propose deterministic and probabilistic versions of the framework. The probabilistic framework utilizes the Variational Bayes Inference approach and is able to capture all the uncertainties present in the data as well as in the deep-learning model. Based on several benchmark examples, we show the predictive capabilities of the framework and discuss its possible limitations. [less ▲]

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See detailSOniCS: Interfacing SOFA and FEniCS for advanced constitutive models
Mazier, Arnaud UL; El Hadramy, Sidaty; Brunet, Jean-Nicolas et al

Scientific Conference (2022, August)

The Simulation Open Framework Architecture (SOFA) is a software environment for building simulations with a particular focus on real-time medical applications, e.g. surgery. Its scope is far broader than ... [more ▼]

The Simulation Open Framework Architecture (SOFA) is a software environment for building simulations with a particular focus on real-time medical applications, e.g. surgery. Its scope is far broader than the FEniCS Project, encompassing e.g. rigid body dynamics, interfacing with haptic devices, contact and visualisation. Naturally, it also includes some finite element models of soft tissue mechanics, but these capabilities are currently ‘pre-baked’ and limited to a few simple constitutive models. The goal of this work is to incorporate state-of-the-art code generation tools from the FEniCS Project into SOFA in order to hugely increase SOFA’s capabilities in terms of soft tissue mechanics. To this end we have developed a new SOFA plugin named SOniCS. For adding a new material model in SOniCS, the user describes its strain energy density function using UFL (Unified Form Language) syntax. Then, using FFCx (FEniCSx Form Compiler) we generate the C code associated with the kernels corresponding to the automatically differentiated cell-local residual and stiffness forms. Finally, we assemble these kernels in SOFA into global tensors and solve the resulting non-linear systems of equations. The result is that it is now possible to straightforwardly implement complex material models such as the Holzapfel-Ogden anisotropic model into SOFA, and to use them alongside SOFA’s existing strong feature set in medical simulation. [less ▲]

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See detailA dynamic programming approach to optimal pollution control under uncertain irreversibility: The Poisson case
Boucekkine, Raouf; Ruan, Weihua; Zou, Benteng UL

E-print/Working paper (2022)

We solve a bimodal optimal control problem with a non-concavity and uncertainty through a Poisson process underlying the transition from a mode to another. We use a dynamic programming approach and are ... [more ▼]

We solve a bimodal optimal control problem with a non-concavity and uncertainty through a Poisson process underlying the transition from a mode to another. We use a dynamic programming approach and are able to uncover the global optimal dynamics (including optimal non-monotonic paths) under a few linear-quadratic assumption, which do not get rid of the non-concavity of the problem. This is in contrast to the related literature on pollution control under irreversibility which usually explores local dynamics along monotonic solution paths to first order Pontryagin conditions. [less ▲]

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See detailLe droit à la sauce piquante n°27 - Aout 2022
Hiez, David UL; Laurent, Rémi

in Le droit à la sauce piquante (2022), 27

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See detailLos pagos por servicios ambientales en la Ciudad de México: un enfoque de coherencia de políticas públicas
Cetina Arenas, Lucero; Koff, Harlan UL; Maganda, Carmen et al

in Región y Sociedad (2022), 34

Objective: to analyze two programs of environmental services payment in the Mexico City Soil Conservation Lands using the policy coherence for development theoretical-methodological framework. Methodology ... [more ▼]

Objective: to analyze two programs of environmental services payment in the Mexico City Soil Conservation Lands using the policy coherence for development theoretical-methodological framework. Methodology: qualitative analysis based on policy coherence typologies. Results: the programs’ beneficiaries economically depend on the associated subsidies; there are restrictions for the economic activities’ development; the financial mechanisms are inefficient and there is a lack of a sustainability vision that considers the socioeconomic dimensions. Limitations: participation of authorities and community members in this type of study is limited and there is a lack of information on the relationships between institutions and work programs. Value: the analysis of peri-urban public policies through the policy coherence for development framework. Conclusions: applying the policy coherence for development framework helped identifying imbalances and synergies among the policy dimensions analyzed. This methodology can promote the mainstreaming of sustainability norms. [less ▲]

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See detailRobust Congestion Control for Demand-Based Optimization in Precoded Multi-Beam High Throughput Satellite Communications
Bui, Van-Phuc; Chien, Trinh-Van; Lagunas, Eva UL et al

in IEEE Transactions on Communications (2022)

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See detailZones and zoning: Linking the geographies of freeports with ArtTech and financial market making
Dörry, Sabine UL; Hesse, Markus UL

in Geoforum (2022)

Freeports and special economic zones (SEZs) are established policy tools to attract foreign investment at specific locations, based on the de-coupling of sovereignty and territory. As a result, they ... [more ▼]

Freeports and special economic zones (SEZs) are established policy tools to attract foreign investment at specific locations, based on the de-coupling of sovereignty and territory. As a result, they emerged not only in developmental contexts, but also in tax havens and financial centres. Recently, freeports and SEZs have shifted from responding to global competition for spaces best suited to attract tangible manufacturing to responding to competition for spaces with best conditions to enable value extraction and wealth shielding. We develop the argument on the emerging industry of ArtTech and new ‘fine art freeports’ that thrive on two core social practices: fracturing property rights to enhance financial liquidity and trading activity in highly exclusive fine-art markets, and offshoring – or zoning – to exploit freeport-facilitated relations for market making and rent-seeking.Besides such practices to make and game markets, freeports supply important physical infrastructure for fine-art technical and custody services that precondition any form of value creation. As such, freeports are important spaces for policy experimentation. Contrary to the conventional belief about free zones in general and freeports in particular, however, their economic impact remains limited. We explain this by conceptualising freeports as ‘zones’ defined or designed by specific processes of ‘zoning’ that link their multiple geographies. We conclude that freeports are no sites of exception but spaces that help legitimise novel institutional and economic arrangements emergent in the economy at large. [less ▲]

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See detailInformalität im regionalen Wachstumsprozess. Einblick in eine „Black Box“ der Planungspraxis am Beispiel Luxemburgs
Schmitz, Nicolas; Hesse, Markus UL; Becker, Tom UL

in Raumforschung und Raumordnung (2022)

Der Beitrag behandelt die Steuerung des Siedlungsflächenwachstums im Großherzogtum Luxemburg aus der Perspektive von Informalität. Luxemburg steht unter einem hohen demographischen und ökonomischen ... [more ▼]

Der Beitrag behandelt die Steuerung des Siedlungsflächenwachstums im Großherzogtum Luxemburg aus der Perspektive von Informalität. Luxemburg steht unter einem hohen demographischen und ökonomischen Wachstumsdruck in allen Landesteilen (Hauptstadt, altindustrialisierter Süden, ländlicher Norden), der das Planungssystem stark herausfordert. Zugleich gibt es keine formelle Regionalplanung, allenfalls Ansätze interkommunaler Kooperation, die überwiegend freiwilliger Natur sind. Anhand von empirischen Fallstudien in zwei wachstumsstarken Gemeinden (Junglinster, Schuttrange) skizziert der Beitrag Planungsentscheidungen im institutionellen Dreieck zwischen Kommune, Staat und privaten Trägern. Informalität dient hier nicht nur zur Kompensation fehlender planerischer Steuerung, sondern auch dem Umgang mit der komplexen Rechtsmaterie des Landes. Informell kommen auch die vitalen Interessen der Grundeigentümer ins Spiel: Da ein Teil der Wohlfahrtseffekte des Landes über Grund und Boden realisiert wird, sind Spekulationsinteressen immanent, haben ein hohes Blockadepotenzial. In diesem Kontext formuliert der Beitrag erste Überlegungen für ein regionales Wachstumsmanagement, das die Lücke zwischen staatlicher Landesplanung und kommunalem Eigensinn schließen könnte. [less ▲]

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See detailAgent-based Model of Initial Token Allocations: Evaluating Wealth Concentration in Fair Launches
Delgado Fernandez, Joaquin UL; Barbereau, Tom Josua UL; Papageorgiou, Orestis UL

E-print/Working paper (2022)

With advancements in distributed ledger technologies and smart contracts, tokenized voting rights gained prominence within Decentralized Finance (DeFi). Voting rights tokens (aka. governance tokens) are ... [more ▼]

With advancements in distributed ledger technologies and smart contracts, tokenized voting rights gained prominence within Decentralized Finance (DeFi). Voting rights tokens (aka. governance tokens) are fungible tokens that grant individual holders the right to vote upon the fate of a project. The motivation behind these tokens is to achieve decentral control. Because the initial allocations of these tokens is often un-democratic, the DeFi project Yearn Finance experimented with a fair launch allocation where no tokens are pre-mined and all participants have an equal opportunity to receive them. Regardless, research on voting rights tokens highlights the formation of oligarchies over time. The hypothesis is that the tokens' tradability is the cause of concentration. To examine this proposition, this paper uses an Agent-based Model to simulate and analyze the concentration of voting rights tokens post fair launch under different trading modalities. It serves to examine three distinct token allocation scenarios considered as fair. The results show that regardless of the allocation, concentration persistently occurs. It confirms the hypothesis that the disease is endogenous: the cause of concentration is the tokens tradablility. The findings inform theoretical understandings and practical implications for on-chain governance mediated by tokens. [less ▲]

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