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See detailÖkologie, Kultur, Großregion: Einführende Überlegungen zu einem komplexen und vielschichtigen Verhältnis
Thiltges, Sébastian UL; Solte-Gresser, Christiane

in Thiltges, Sébastian; Solte-Gresser, Christiane (Eds.) Kulturökologie und ökologische Kulturen in der Großregion (2020, December)

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See detailFrontières liquides : l’eau dans les romans de la terre au Luxembourg
Thiltges, Sébastian UL

in Thiltges, Sébastian; Solte-Gresser, Christiane (Eds.) Ecologie culturelle et cultures écologiques dans la Grande Région (2020, December)

While the earth usually represents the element in which cultural attachment is rooted, water on the contrary reveals what exceeds or interpenetrates the land. The liquid element is as ambiguous as it is ... [more ▼]

While the earth usually represents the element in which cultural attachment is rooted, water on the contrary reveals what exceeds or interpenetrates the land. The liquid element is as ambiguous as it is proteiform: vital and destructive at the same time, it sometimes is a figure of liberation, sometimes of tragic dissolution. In a corpus of Luxembourgish novels from the early 20th century, this paper will analyse the depictions of water, mostly in its opposition with the soil, in order to question the meaning of the liquid element in a context where, corollary to social, economic and political changes, the earth is generally dominant in discourse and imagination. If nature has mostly been confined to the local and cultural landscape, an eco-material reading highlights on the contrary a global and crossborder dimension inherent to nature, but also to culture, disregarding the map-drawn boundaries that define the individual and the collective. Finally, a sensitive, anthropoetical reading also challenges historical, contextual and fictional frames. The materiality of the liquid element is not just a metaphor: it shapes natural, as well as textual environments. [less ▲]

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See detailIn-plane magnetic field-driven symmetry breaking in topological insulator-based three-terminal junctions
Kölzer, Jonas; Moors, Kristof; Schmidt, Thomas UL et al

E-print/Working paper (2020)

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See detailPrésences et déplacements des souverains de la Francie médiane de 843 à 869: Contribution à l'étude de l'espace politique de Lothaire Ier et Lothaire II
Pettiau, Hérold UL

in Pettinger, Maxime (Ed.) D'un regnum à l'autre. La Lotharingie, un espace de l'entre-deux? Von Regnum hum Imperium. Lotharingien als Zwischenreich? (2020, December)

This contribution is devoted to the analysis of the movements made by Emperor Lothar I and his son, King Lothar II, by proposing to distinguish between three types of movement: movements at the beginning ... [more ▼]

This contribution is devoted to the analysis of the movements made by Emperor Lothar I and his son, King Lothar II, by proposing to distinguish between three types of movement: movements at the beginning of the reign, "usual" movements during the reign and movements that would be described as "punctual", of a pendular type. The importance and nature of multilateral meetings between sovereigns is taken into account. This comparison highlights a certain permanence in the use of a stable palatial zone by the two sovereigns, between the Meuse and Eifel on the one hand and a Moselle axis from Thionville to Remiremont on the other, but also, beyond the variety of contexts, similarities in the more exceptional movements, which remain largely concentrated in the Francia media area, a part that fell to Lothaire after the Treaty of Verdun. [less ▲]

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See detailGeneralized Multiplexed Waveform Design Framework for Cost-Optimized MIMO Radar
Hammes, C.; R., B. S. M.; Ottersten, Björn UL

in IEEE Transactions on Signal Processing (2020), 69

Cost-optimization through the minimization of hardware and processing costs with minimal loss in performance is an interesting design paradigm in evolving and emerging Multiple-Input-Multiple-Output (MIMO ... [more ▼]

Cost-optimization through the minimization of hardware and processing costs with minimal loss in performance is an interesting design paradigm in evolving and emerging Multiple-Input-Multiple-Output (MIMO) radar systems. This optimization is a challenging task due to the increasing Radio Frequency (RF) hardware complexity as well as the signal design algorithm complexity in applications requiring high angular resolution. Towards addressing these, the paper proposes a low-complexity signal design framework, which incorporates a generalized time multiplex scheme for reducing the RF hardware complexity with a subsequent discrete phase modulation. The scheme further aims at achieving simultaneous transmit beamforming and maximum virtual MIMO aperture to enable better target detection and discrimination performance. Furthermore, the paper proposes a low-complexity signal design scheme for beampattern matching in the aforementioned setting. The conducted performance evaluation indicates that the listed design objectives are met. [less ▲]

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See detailCommon diseases alter the physiological age-related blood microRNA profile.
Fehlmann, Tobias; Lehallier, Benoit; Schaum, Nicholas et al

in Nature communications (2020), 11(1), 5958

Aging is a key risk factor for chronic diseases of the elderly. MicroRNAs regulate post-transcriptional gene silencing through base-pair binding on their target mRNAs. We identified nonlinear changes in ... [more ▼]

Aging is a key risk factor for chronic diseases of the elderly. MicroRNAs regulate post-transcriptional gene silencing through base-pair binding on their target mRNAs. We identified nonlinear changes in age-related microRNAs by analyzing whole blood from 1334 healthy individuals. We observed a larger influence of the age as compared to the sex and provide evidence for a shift to the 5' mature form of miRNAs in healthy aging. The addition of 3059 diseased patients uncovered pan-disease and disease-specific alterations in aging profiles. Disease biomarker sets for all diseases were different between young and old patients. Computational deconvolution of whole-blood miRNAs into blood cell types suggests that cell intrinsic gene expression changes may impart greater significance than cell abundance changes to the whole blood miRNA profile. Altogether, these data provide a foundation for understanding the relationship between healthy aging and disease, and for the development of age-specific disease biomarkers. [less ▲]

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See detailExperimenter Effects in Children Using the Smileyometer Scale
Lehnert, Florence Kristin UL; Lallemand, Carine UL; Fischbach, Antoine UL et al

Scientific Conference (2020, November 19)

Researchers in the social sciences like human-computer interaction face novel challenges concerning the development of methods and tools for evaluating interactive technology with children. One of these ... [more ▼]

Researchers in the social sciences like human-computer interaction face novel challenges concerning the development of methods and tools for evaluating interactive technology with children. One of these challenges is related to the validity and reliability of user experience measurement tools. Scale designs, like the Smileyometer, have been proven to contain biases such as the tendency for children to rate almost every technology as great. This explorative paper discusses a possible effect of two experimenter styles on the distribution of 6-8 years old pupils' ratings (N= 73) to the Smileyometer. We administered the scale before and after a tablet-based assessment in two schools. Experimenter 1 employed a child-directed speech compared to a monotone speech of Experimenter 2. While brilliant (5 out of 5) was the most frequent answer option in all conditions, the mean scores were higher and associated with a lower variability across both conditions for Experimenter 2. We discuss a possible experimenter effect in the Smileyometer and implications for evaluating children’s user experiences. [less ▲]

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See detailMulti-Channel Joint Forecasting-Scheduling for the Internet of Things
Rodoplu, Volkan; Nakip, Mert; Qorbanian, Roozbeh UL et al

in IEEE Access (2020), 8

We develop a methodology for Multi-Channel Joint Forecasting-Scheduling (MC-JFS) targeted at solving the Medium Access Control (MAC) layer Massive Access Problem of Machine-to-Machine (M2M) communication ... [more ▼]

We develop a methodology for Multi-Channel Joint Forecasting-Scheduling (MC-JFS) targeted at solving the Medium Access Control (MAC) layer Massive Access Problem of Machine-to-Machine (M2M) communication in the presence of multiple channels, as found in Orthogonal Frequency Division Multiple Access (OFDMA) systems. In contrast with the existing schemes that merely react to current traffic demand, Joint Forecasting-Scheduling (JFS) forecasts the traffic generation pattern of each Internet of Things (IoT) device in the coverage area of an IoT Gateway and schedules the uplink transmissions of the IoT devices over multiple channels in advance, thus obviating contention, collision and handshaking, which are found in reactive protocols. In this paper, we present the general form of a deterministic scheduling optimization program for MC-JFS that maximizes the total number of bits that are delivered over multiple channels by the delay deadlines of the IoT applications. In order to enable real-time operation of the MC-JFS system, first, we design a heuristic, called Multi-Channel Look Ahead Priority based on Average Load (MC-LAPAL), that solves the general form of the scheduling problem. Second, for the special case of identical channels, we develop a reduction technique by virtue of which an optimal solution of the scheduling problem is computed in real time. We compare the network performance of our MC-JFS scheme against Multi-Channel Reservation-based Access Barring (MC-RAB) and Multi-Channel Enhanced Reservation-based Access Barring (MC-ERAB), both of which serve as benchmark reactive protocols. Our results show that MC-JFS outperforms both MC-RAB and MC-ERAB with respect to uplink cross-layer throughput and transmit energy consumption, and that MC-LAPAL provides high performance as an MC-JFS heuristic. Furthermore, we show that the computation time of MC-LAPAL scales approximately linearly with the number of IoT devices. This work serves as a foundation for building scalable JFS schemes at IoT Gateways in the near future. [less ▲]

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See detailTransfer Learning and Meta Learning Based Fast Downlink Beamforming Adaptation
Yuan, Yi; Zheng, G.; Wong, K.-K. et al

in IEEE Transactions on Wireless Communications (2020)

This paper studies fast adaptive beamforming optimization for the signal-to-interference-plus-noise ratio balancing problem in a multiuser multiple-input single-output downlink system. Existing deep ... [more ▼]

This paper studies fast adaptive beamforming optimization for the signal-to-interference-plus-noise ratio balancing problem in a multiuser multiple-input single-output downlink system. Existing deep learning based approaches to predict beamforming rely on the assumption that the training and testing channels follow the same distribution which may not hold in practice. As a result, a trained model may lead to performance deterioration when the testing network environment changes. To deal with this task mismatch issue, we propose two offline adaptive algorithms based on deep transfer learning and meta-learning, which are able to achieve fast adaptation with the limited new labelled data when the testing wireless environment changes. Furthermore, we propose an online algorithm to enhance the adaptation capability of the offline meta algorithm in realistic non-stationary environments. Simulation results demonstrate that the proposed adaptive algorithms achieve much better performance than the direct deep learning algorithm without adaptation in new environments. The meta-learning algorithm outperforms the deep transfer learning algorithm and achieves near optimal performance. In addition, compared to the offline meta-learning algorithm, the proposed online meta-learning algorithm shows superior adaption performance in changing environments. [less ▲]

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See detailHow do pupils experience Technology-Based Assessments? Implications for methodological approaches to measuring the User Experience based on two case studies in France and Luxembourg
Lehnert, Florence Kristin UL; Lallemand, Carine UL; Fischbach, Antoine UL et al

Scientific Conference (2020, November 12)

Technology-based assessments (TBAs) are widely used in the education field to examine whether the learning goals were achieved. To design fair and child-friendly TBAs that enable pupils to perform at ... [more ▼]

Technology-based assessments (TBAs) are widely used in the education field to examine whether the learning goals were achieved. To design fair and child-friendly TBAs that enable pupils to perform at their best (i.a. independent of individual differences in computer literacy), we must ensure reliable and valid data collection. By reducing Human-Computer Interaction issues, we provide the best possible assessment conditions and user experience (UX) with the TBA and reduce educational inequalities. Good UX is thus a prerequisite for better data validity. Building on a recent case study, we investigated how pupils perform TBAs in real-life settings. We addressed the context-dependent factors resulting from the observations that ultimately influence the UX. The first case study was conducted with pupils age 6 to 7 in three elementary schools in France (n=61) in collaboration with la direction de l’évaluation, de la prospective et de la performance (DEPP). The second case study was done with pupils age 12 to 16 in four secondary schools in Luxembourg (n=104) in collaboration with the Luxembourg Centre for Educational Testing (LUCET). This exploratory study focused on the collection of various qualitative datasets to identify factors that influence the interaction with the TBA. We also discuss the importance of teachers’ moderation style and mere system-related characteristics, such as audio protocols of the assessment data. This study contribution comprises design recommendations and implications for methodological approaches to measuring pupils’ user experience during TBAs. [less ▲]

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See detailAuction-based Multi-Channel Cooperative Spectrum Sharing in Hybrid Satellite-Terrestrial IoT Networks
Zhang, Xiaokai; Guo, Daoxing; An, Kang et al

in IEEE Internet of Things Journal (2020)

In this paper, we investigate the multi-channel cooperative spectrum sharing in hybrid satellite-terrestrial internet of things (IoT) networks with the auction mechanism, which is designed to reduce the ... [more ▼]

In this paper, we investigate the multi-channel cooperative spectrum sharing in hybrid satellite-terrestrial internet of things (IoT) networks with the auction mechanism, which is designed to reduce the operational expenditure of the satellitebased IoT (S-IoT) network while alleviating the spectrum scarcity issues of terrestrial-based IoT (T-IoT) network. The cluster heads of selected T-IoT networks assist the primary satellite users transmission through cooperative relaying techniques in exchange for spectrum access. We propose an auction-based optimization problem to maximize the sum transmission rate of all primary S-IoT receivers with the appropriate secondary network selection and corresponding radio resource allocation profile by the distributed implementation while meeting the minimum transmission rate of secondary receivers of each TIoT network. Specifically, the one-shot Vickrey-Clarke-Groves (VCG) auction is introduced to obtain the maximum social welfare, where the winner determination problem is transformed into an assignment problem and solved by the Hungarian algorithm. To further reduce the primary satellite network decision complexity, the sequential Vickrey auction is implemented by sequential fashion until all channels are auctioned. Due to incentive compatibility with those two auction mechanisms, the secondary T-IoT cluster yields the true bids of each channel, where both the non-orthogonal multiple access (NOMA) and time division multiple access (TDMA) schemes are implemented in cooperative communication. Finally, simulation results validate the effectiveness and fairness of the proposed auction-based approach as well as the superiority of the NOMA scheme in secondary relays selection. Moreover, the influence of key factors on the performance of the proposed scheme is analyzed in detail. [less ▲]

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See detailInstruction Coverage for Android App Testing and Tuning
Pilgun, Aleksandr UL

Doctoral thesis (2020)

For many people, mobile apps have already become an indispensable part of modern life. Apps entertain, educate, assist us in our daily routines and help us connect with others. However, the advanced ... [more ▼]

For many people, mobile apps have already become an indispensable part of modern life. Apps entertain, educate, assist us in our daily routines and help us connect with others. However, the advanced capabilities of modern devices running the apps and sensitive user data make mobile devices also an attractive attack target. To get access to sensitive data, adversaries tend to conceal malicious functionality in freely distributed legitimately-looking apps. The problem of low-quality and malicious apps, spreading at an enormous scale, is especially relevant for one of the biggest software repositories – Google Play. The Android apps distributed through this platform undergo a validation process by Google. However, that is insufficient to confirm their good nature. To identify dangerous apps, novel frameworks for testing and app analysis are being developed by the Android community. Code coverage is one of the most common metrics for evaluating the effectiveness of these frameworks, and it is used as an internal metric to guide code exploration in some of them. However, when analyzing apps without source code, the Android community relies mostly on method coverage since there are no reliable tools for measuring finer-grained code coverage in 3rd-party Android app testing. Another stumbling block for testing frameworks is the inability to test an app exhaustively. While code coverage measurement can indicate an improvement in testing, it is neither possible to reach 100% coverage nor to identify the maximum reachable coverage value for the app. Despite testing, the app still contains high amounts of not executed code, which makes it impossible to confirm the absence of potentially malicious code in the part of the app that has not been tested. The existing static debloating approaches aim at app size minimization rather than security and simply debloat not reachable code. However, there is currently no approach to debloat apps based on dynamic analysis information, i.e. to cut out not-executed code. In this dissertation, we solve these two problems by, first, proposing an efficient approach and a tool to measure code coverage at the instruction level, and second, a dynamic binary shrinking methodology for deleting not executed code from the app. We support our solutions by the following contributions: - An instrumentation approach to measure code coverage at the instruction level. Our technique instruments smali representation of Android bytecode to allow code coverage measurement at the finest level. - An implementation of the instrumentation approach. ACVTool is a self-contained package containing 4K lines of Python code. It is publicly available and can be integrated into different testing frameworks. - An extensive empirical evaluation that shows the high reliability and versatility of our approach. ACVTool successfully executes on 96.9% of apps from our dataset, introduces a negligible instrumentation time and runtime overheads, and its results are complaint to the results of JaCoCo (source code coverage) and Ella (method coverage) tools. - A detailed study on the influence of code coverage metric granularity on automated testing. We demonstrate the usefulness of ACVTool for automated testing techniques that rely on code coverage data in their operation. - A dynamic debloating approach based on ACVTool instruction coverage. We propose Dynamic Binary Shrinking System, a novel methodology created to shrink 3rd-party Android apps towards observed benign functionality on executed code. - An implementation of the dynamic debloating technique incorporated into the ACVCut tool. The tool demonstrates the viability of the Dynamic Shrinking System on two examples. It allows us to cut out not executed code and, thus, provide 100% instruction coverage on explored app behaviors. [less ▲]

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See detailEin Blick auf aktuelle Entwicklungen bei Blockchains und deren Auswirkungen auf den Energieverbrauch
Sedlmeir, Johannes; Ulrich Buhl, Hans; Fridgen, Gilbert UL et al

in Informatik-Spektrum (2020)

The enormous power consumption of Bitcoin has led to undifferentiated discussions in science and practice about the sustainability of blockchain and distributed ledger technology in general. However ... [more ▼]

The enormous power consumption of Bitcoin has led to undifferentiated discussions in science and practice about the sustainability of blockchain and distributed ledger technology in general. However, blockchain technology is far from homogeneous—not only with regard to its applications, which now go far beyond cryptocurrencies and have reached businesses and the public sector, but also with regard to its technical characteristics and, in particular, its power consumption. This paper summarizes the status quo of the power consumption of various implementations of blockchain technology, with special emphasis on the recent ‘‘Bitcoin Halving’’ and so-called ‘‘zk-rollups’’. We argue that although Bitcoin and other proof-of-work blockchains do indeed consume a lot of power, alternative blockchain solutions with significantly lower power consumption are already available today, and new promising concepts are being tested that could further reduce in particulary the power consumption of large blockchain networks in the near future. From this we conclude that although the criticism of Bitcoin’s power consumption is legitimate, it should not be used to derive an energy problem of blockchain technology in general. In many cases in which processes can be digitized or improved with the help of more energy-efficient blockchain variants, one can even expect net energy savings. [less ▲]

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See detailRoles of bacteriophages, plasmids and CRISPR immunity in microbial community dynamics revealed using time-series integrated meta-omics
Martinez Arbas, Susana UL; Narayanasamy, Shaman; Herold, Malte et al

in Nature Microbiology (2020)

Viruses and plasmids (invasive mobile genetic elements (iMGEs)) have important roles in shaping microbial communities, but their dynamic interactions with CRISPR-based immunity remain unresolved. We ... [more ▼]

Viruses and plasmids (invasive mobile genetic elements (iMGEs)) have important roles in shaping microbial communities, but their dynamic interactions with CRISPR-based immunity remain unresolved. We analysed generation-resolved iMGE–host dynamics spanning one and a half years in a microbial consortium from a biological wastewater treatment plant using integrated meta-omics. We identified 31 bacterial metagenome-assembled genomes encoding complete CRISPR–Cas systems and their corresponding iMGEs. CRISPR-targeted plasmids outnumbered their bacteriophage counterparts by at least fivefold, highlighting the importance of CRISPR-mediated defence against plasmids. Linear modelling of our time-series data revealed that the variation in plasmid abundance over time explained more of the observed community dynamics than phages. Community-scale CRISPR-based plasmid–host and phage–host interaction networks revealed an increase in CRISPR-mediated interactions coinciding with a decrease in the dominant ‘Candidatus Microthrix parvicella’ population. Protospacers were enriched in sequences targeting genes involved in the transmission of iMGEs. Understanding the factors shaping the fitness of specific populations is necessary to devise control strategies for undesirable species and to predict or explain community-wide phenotypes. [less ▲]

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See detailAlterations in Neural Responses and Pain Perception in Older Adults During Distraction
Gonzalez-Roldan, Ana Maria; Terrasa, Juan Lorenzo; Sitges, Carolina et al

in Psychosomatic Medicine (2020), 82

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See detailMechanisms of Ras Membrane Organization and Signaling: Ras Rocks Again.
Abankwa, Daniel UL; Gorfe, Alemayehu A.

in Biomolecules (2020), 10(11),

Ras is the most frequently mutated oncogene and recent drug development efforts have spurred significant new research interest. Here we review progress toward understanding how Ras functions in nanoscale ... [more ▼]

Ras is the most frequently mutated oncogene and recent drug development efforts have spurred significant new research interest. Here we review progress toward understanding how Ras functions in nanoscale, proteo-lipid signaling complexes on the plasma membrane, called nanoclusters. We discuss how G-domain reorientation is plausibly linked to Ras-nanoclustering and -dimerization. We then look at how these mechanistic features could cooperate in the engagement and activation of RAF by Ras. Moreover, we show how this structural information can be integrated with microscopy data that provide nanoscale resolution in cell biological experiments. Synthesizing the available data, we propose to distinguish between two types of Ras nanoclusters, an active, immobile RAF-dependent type and an inactive/neutral membrane anchor-dependent. We conclude that it is possible that Ras reorientation enables dynamic Ras dimerization while the whole Ras/RAF complex transits into an active state. These transient di/oligomer interfaces of Ras may be amenable to pharmacological intervention. We close by highlighting a number of open questions including whether all effectors form active nanoclusters and whether there is an isoform specific composition of Ras nanocluster. [less ▲]

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See detailMIGRATION INTERNATIONALE AU LUXEMBOURG Système d’observation permanente des migrations (OCDE)
Sommarribas, Adolfo UL; Nienaber, Birte UL

Report (2020)

Le Luxembourg reste un pays attractif en termes d’immigration ; entre 2018 et 2019, la population du Grand-Duché a augmenté de 2 %. La part de la population luxembourgeoise représente 59,1 % de cette ... [more ▼]

Le Luxembourg reste un pays attractif en termes d’immigration ; entre 2018 et 2019, la population du Grand-Duché a augmenté de 2 %. La part de la population luxembourgeoise représente 59,1 % de cette croissance contre 40,9 % de nationalités étrangères. L’immigration nette reste le principal facteur expliquant l’augmentation de la population. Le solde migratoire est largement positif pour les ressortissants de nationalité étrangère (12 142) alors qu’il est négatif pour les ressortissants luxembourgeois (-1 067). Le deuxième élément explicatif réside dans le solde naturel global positif (1 947). Si ce solde est largement positif chez les ressortissants étrangers, il est négatif chez les Luxembourgeois. Le regroupement familial reste le principal motif d’immigration pour les ressortissants de pays tiers. Ce type de migration devance l’immigration pour motifs économiques et la migration basée sur la recherche d’une protection internationale. Le nombre de personnes sollicitant une protection internationale est resté à un niveau élevé en 2019 avec 2 047 demandes, même si ce nombre constitue une diminution de 7,1 % par rapport à l’année précédente. En 2019, plusieurs évolutions majeures dans le domaine de l’immigration légale sont à noter. Parmi ces évolutions figurent notamment : l’introduction d’un visa de longue durée visant à simplifier l’entrée et le séjour des ressortissants de pays tiers sans devoir solliciter l’obtention d’un titre de séjour, ainsi que l’adoption de quatre lois tendant à clarifier le statut des ressortissants britanniques résidant au Luxembourg. La loi sur l’immigration a connu d’autres modifications importantes dans le domaine de la lutte contre la migration irrégulière et la rétention et le retour des ressortissants de pays tiers sans droit de séjour. La coopération internationale s’est poursuivie en matière de réadmission, comme le montre l’entrée en vigueur du protocole entre les États du Benelux et le gouvernement de la République de Serbie sur la mise en œuvre de l’accord conclu entre l’UE et la République de Serbie concernant la réadmission des personnes en situation de séjour irrégulier. -Ainsi, l’adoption des projets de loi portant approbation des protocoles en matière de réadmission avec l’Arménie et l’Ukraine. Un changement institutionnel significatif a eu lieu en matière de protection internationale : la loi du 4 novembre 2019 portant création de l’Office national de l’accueil (ONA) a opéré le transfert des compétences relatives à l’accueil des demandeurs de protection internationale du Ministère de la Famille, de l’Intégration et à la Grande Région vers le ministère ayant l’Immigration dans ses attributions. Avec l'entrée en vigueur de la loi au 1er janvier 2020, l'ONA s'est substitué à l'Office luxembourgeois de l'accueil et de l'intégration (OLAI) et a été rattaché au Secrétariat général du ministère des Affaires étrangères et européennes. L’intégration demeure une compétence du ministère de la Famille, de l'Intégration et à la Grande Région. Le 1er janvier 2019, la loi sur le revenu d’inclusion sociale (REVIS) est entrée en vigueur. Une des nouvelles dispositions est que tous les bénéficiaires d’une protection internationale âgés de 25 ans ou plus, de même que les membres de leur famille, peuvent bénéficier du REVIS, sans devoir remplir la condition des 5 ans de résidence au Luxembourg au cours des 20 dernières années. L’hébergement des demandeurs de protection internationale (DPI) reste un défi de taille et les taux d’occupation dans les structures d’hébergement de l’ONA continuent à se situer à des niveaux très élevés. Ceci est notamment dû au fait que la crise du logement affecte particulièrement les bénéficiaires de protection internationale (BPI) qui peinent à trouver un logement privé et à se loger en-dehors des structures d’accueil réservées en principe aux DPI. Dans ce contexte l’ONA a poursuivi ses efforts à inciter les communes à promouvoir la mise en place de structures d’hébergement pour DPI ou de possibilités d’hébergement pour BPI. Sur le plan de la lutte contre la traite des êtres humains les structures d’accueil et de consultation ont été élargies en 2019, notamment pour les hommes victimes de traite. Au niveau international, une déclaration d’intention concernant les nouvelles étapes dans leur coopération transfrontalière pour combattre la traite des êtres humains a été signé le 10 décembre 2019 par les pays du Benelux. Sur le plan des politiques d’intégration, les autorités ont continué à mettre en œuvre le Plan d’action national pluriannuel d’intégration à travers des appels à projets. Les actions visant à promouvoir l’intégration au niveau local ont également été renforcées, comme en témoignent la promotion du développement de plans communaux d’intégration et le soutien financier apporté aux communes par les pouvoirs publics. Le débat parlementaire sur le racisme a conduit à l’adoption d’une motion invitant le gouvernement à réaliser une étude sur le racisme et les discriminations au Luxembourg et d’une résolution dans laquelle la Chambre des Députés s'engage à renforcer les moyens du Centre d’Egalite de Traitement (CET). L’année 2020 a été marquée par la crise sanitaire liée à la Covid-19. La crise sanitaire et les mesures mises en place par les gouvernements, ont fortement impacté la mobilité et les migrations. Contrairement à la France, la Belgique et, surtout, l'Allemagne, le Luxembourg n'a jamais fermé ses frontières. Dans ce contexte le Ministère des Affaires étrangères et européennes a été contraint de négocier des accords avec ses homologues des pays voisins afin d’assurer la continuité du travail des frontaliers, notamment pour ceux travaillant dans le secteur de la santé. [less ▲]

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See detailLarge scale realistic virtual environments for lunar robotics testing using real-time computer games engines
Ludivig, Philippe UL; Voos, Holger UL; Lamamy, Julien

Poster (2020, October 23)

Virtual simulation environments are a great tool for testing different rover systems before they are sent to the moon. They allow for perfect repeatability and give abetter idea how specific parameters ... [more ▼]

Virtual simulation environments are a great tool for testing different rover systems before they are sent to the moon. They allow for perfect repeatability and give abetter idea how specific parameters can impact the overall system. Most current simulators however suffer from low visual fidelity which is problematic for testing the vision sensors needed for autonomous navigation.Additionally, due to technical and practical limitations, most simulations are limited in environment scale. This is problematic for long range navigation testing needed for missions such as the mars sample fetch rover[1]. In order to solve both issues, we turn towards a popular computer game engine,Unreal Engine 4. It allows for larger environments than what is currently possible in robotics simulators such as Gazebo[2]or V-rep[3]. It also addresses the visual fidelity with a range of tools including real-time ray-tracing.The tradeoff is a low physics fidelity, which can be an issue when testing wheel-soil interaction. For our use-case we focus primarily on perception systems needed for rover navigation, such as mono and stereo camera systems, where visual fidelity is more important. [less ▲]

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See detailABSOLUTE LOCALIZATION FOR SURFACE ROBOTICS IN GPS-DENIED ENVIRONMENTS USING A NEURAL NETWORK.
Wu, Ben; Ludivig, Philippe UL; Potter, Ross et al

Poster (2020, October 23)

Accurate localization in surface robotics is essential for navigation, path planning, and science objectives. On Earth, absolute localization can be readily achieved via satellite navigation (e.g., GPS ... [more ▼]

Accurate localization in surface robotics is essential for navigation, path planning, and science objectives. On Earth, absolute localization can be readily achieved via satellite navigation (e.g., GPS). For other planetary bodies such as the Moon or Mars, however, such systems are unavailable. Current methods for absolute localization of planetary rovers rely on time- and labor-intensive human visual matching of surface perspective features with satellite images. Relative localization also accumulates errors over time, with different methods estimating dissimilar locations (e.g., [1]). Thus, an absolute localization method that can quickly, automatically, and accurately reduce the position search space is of great benefit to future planetary exploration missions. This project [2] presents a new approach to localizing planetary rovers: training an artificial neural network to match surfaceperspective imagery to corresponding satellite maps. [less ▲]

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See detailProblems in nonequilibrium fluctuations across scales: A path integral approach
Cossetto, Tommaso UL

Doctoral thesis (2020)

In this thesis we study stochastic systems evolving with Markov jump processes. In a first work we discuss different representations of the stochastic evolution: the master equation, the generalized ... [more ▼]

In this thesis we study stochastic systems evolving with Markov jump processes. In a first work we discuss different representations of the stochastic evolution: the master equation, the generalized Langevin equation, and their path integrals. The description is used to derive the generating functions for out of equilibrium observables, together with the typical approximation techniques. In a second work the path integral is used to enforce thermodynamic consistency across scales. The description of identical units with all-to-al interactions is reduced from a micro- to a meso- to a macroscopic level. A suitable scaling of the dynamics and of the thermodynamic observables allows to preserve the thermodynamical structure at the different levels. In a third work we focus on the large deviation properties of chemical networks. The path integral allows to compute the dominant trajectories that constitute macroscopic fluctuations. For bi-stable systems the existence of multiple macroscopic contributions results in a phase transition for the macroscopic current. In a fourth work we study the response of such chemical currents to external perturbations. Out of equilibrium the system can display negative differential response, a feature that offers different strategies to minimize external or internal disturbances. Finally, in a fifth work, we start from a quantum system where part of the system can be traced out to act as multiple reservoirs at different temperatures. Using the Schwinger-Keldysh contour and Green's functions we can obtain the generating function for the different parts of the hamiltonian. The statistics of thermodynamic observables is accessible even in the strong coupling regime, while the semi-classical approximation is in agreement with the classical counterpart. [less ▲]

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