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See detailGuest Editor, Journal of Risk and Financial Management
Wolff, Christiaan UL

in Wolff, Christiaan (Ed.) The Financial System in a Post COVID-19 World (2021)

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See detailMining App Lineages: A Security Perspective
Gao, Jun UL

Doctoral thesis (2021)

Direct inter-app code invocation in Android apps and its evolution: The Android ecosystem offers different facilities to enable communication among app components and across apps to ensure that rich ... [more ▼]

Direct inter-app code invocation in Android apps and its evolution: The Android ecosystem offers different facilities to enable communication among app components and across apps to ensure that rich services can be composed through functionality reuse. At the heart of this system is the Inter-component communication (ICC) scheme, which has been largely studied in the literature. Less known in the community is another powerful mechanism that allows for direct inter-app code invocation which opens up for different reuse scenarios, both legitimate or malicious. In this dissertation, we expose the general workflow for this mechanism, which beyond ICCs, enables app developers to access and invoke functionalities (either entire Java classes, methods or object fields) implemented in other apps using official Android APIs. We experimentally showcase how this reuse mechanism can be leveraged to “plagiarize" supposedly-protected functionalities. Typically, we could leverage this mechanism to bypass security guards that a popular video broadcaster has placed for preventing access to its video database from outside its provided app. We further contribute with a static analysis toolkit, named DICIDer, for detecting direct inter-app code invocations in apps. An empirical analysis of the usage prevalence and evolution of this reuse mechanism is then conducted. [less ▲]

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See detailAssociate Editor, Pacific-Basin Finance Journal
Wolff, Christiaan UL

Diverse speeches and writings (2021)

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See detailMember, Managing Board, European Banking Center Network
Wolff, Christiaan UL

Diverse speeches and writings (2021)

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See detailAssociate Editor, Journal of Risk and Financial Management
Wolff, Christiaan UL

Diverse speeches and writings (2021)

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See detailManaging residence permits and unemployment of third-country nationals during the COVID-19 crisis in the EU
Sommarribas, Adolfo UL

in Journaal Vreemdelingenrecht (2020), 19(4), 14-21

This article will try to provide a state of play of the response of the EU Member States to the COVID-19 crisis in regard to third-country nationals through the information compiled by the European ... [more ▼]

This article will try to provide a state of play of the response of the EU Member States to the COVID-19 crisis in regard to third-country nationals through the information compiled by the European Migration Network between 3 February until 15 June 2020. It will draw a state of play of the actions taken by Member States to confront the spread of the coronavirus in the immigration context. It also will focus on the validity of residence permits and the dispositions taken to avoid that legal migrants fall in an irregular situation and the effects of unemployment in regard to their residence permits. However, the article will not draw a timeline on when the actions were taken. [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 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 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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See detailJoint Bit Allocation and Hybrid Beamforming Optimization for Energy Efficient Millimeter Wave MIMO Systems
Kaushik, Aryan; Vlachos, Evangelos; Tsinos, Christos et al

in IEEE Transactions on Green Communications and Networking (2020)

In this paper, we aim to design highly energy efficient end-to-end communication for millimeter wave multiple-input multiple-output systems. This is done by jointly optimizing the digital-to-analog ... [more ▼]

In this paper, we aim to design highly energy efficient end-to-end communication for millimeter wave multiple-input multiple-output systems. This is done by jointly optimizing the digital-to-analog converter (DAC)/analog-to-digital converter (ADC) bit resolutions and hybrid beamforming matrices. The novel decomposition of the hybrid precoder and the hybrid combiner to three parts is introduced at the transmitter (TX) and the receiver (RX), respectively, representing the analog precoder/combiner matrix, the DAC/ADC bit resolution matrix and the baseband precoder/combiner matrix. The unknown matrices are computed as a solution to the matrix factorization problem where the optimal fully digital precoder or combiner is approximated by the product of these matrices. A novel and efficient solution based on the alternating direction method of multipliers is proposed to solve these problems at both the TX and the RX. The simulation results show that the proposed solution, where the DAC/ADC bit allocation is dynamic during operation, achieves higher energy efficiency when compared with existing benchmark techniques that use fixed DAC/ADC bit resolutions. [less ▲]

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See detailLeo-III 1.5
Steen, Alexander UL

Software (2020)

Leo-III is an automated theorem prover for (polymorphic) higher-order logic which supports all common TPTP dialects, including THF, TFF and FOF as well as their rank-1 polymorphic derivatives. It is based ... [more ▼]

Leo-III is an automated theorem prover for (polymorphic) higher-order logic which supports all common TPTP dialects, including THF, TFF and FOF as well as their rank-1 polymorphic derivatives. It is based on a paramodulation calculus with ordering constraints and, in tradition of its predecessor LEO-II, heavily relies on cooperation with external (mostly first-order) theorem provers for increased performance. Nevertheless, Leo-III can also be used as a stand-alone prover without employing any external cooperation. In addition for its HOL reasoning capabilities, Leo-III supports reasoning in many higher-order quantified modal logics. [less ▲]

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See detailDebugging Inputs
Kirschner, Lukas; Soremekun, Ezekiel UL; Zeller, Andreas

in Proceedings of the ACM/IEEE 42nd International Conference on Software Engineering (2020, June)

When a program fails to process an input, it need not be the program code that is at fault. It can also be that the input data is faulty, for instance as result of data corruption. To get the data ... [more ▼]

When a program fails to process an input, it need not be the program code that is at fault. It can also be that the input data is faulty, for instance as result of data corruption. To get the data processed, one then has to debug the input data—that is, (1) identify which parts of the input data prevent processing, and (2) recover as much of the (valuable) input data as possible. In this paper, we present a general-purpose algorithm called ddmax that addresses these problems automatically. Through experiments, ddmax maximizes the subset of the input that can still be processed by the program, thus recovering and repairing as much data as possible; the difference between the original failing input and the “maximized” passing input includes all input fragments that could not be processed. To the best of our knowledge, ddmax is the first approach that fixes faults in the input data without requiring program analysis. In our evaluation, ddmax repaired about 69% of input files and recovered about 78% of data within one minute per input. [less ▲]

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See detailDeep Channel Learning For Large Intelligent Surfaces Aided mm-Wave Massive MIMO Systems
Elbir, Ahmet M.; Papazafeiropoulos, Anastasios; Kourtessis, Pandelis et al

in IEEE Wireless Communications Letters (2020), 9(Sept. 2020), 1447-1451

This letter presents the first work introducing a deep learning (DL) framework for channel estimation in large intelligent surface (LIS) assisted massive MIMO (multiple-input multiple-output) systems. A ... [more ▼]

This letter presents the first work introducing a deep learning (DL) framework for channel estimation in large intelligent surface (LIS) assisted massive MIMO (multiple-input multiple-output) systems. A twin convolutional neural network (CNN) architecture is designed and it is fed with the received pilot signals to estimate both direct and cascaded channels. In a multi-user scenario, each user has access to the CNN to estimate its own channel. The performance of the proposed DL approach is evaluated and compared with state-of-the-art DL-based techniques and its superior performance is demonstrated. [less ▲]

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See detailPromoting Elementary-School Teachers’ Diagnostic Skills to Recognize their Students’ Academic Potential
Krischler, Mireille UL; Breit, Moritz; Preckel, Franzis

Poster (2020, April)

We present a five-year project aimed at improving teachers’ skills to detect mathematical and scientific talent in elementary school students. Within the project, teachers from 23 German schools and ... [more ▼]

We present a five-year project aimed at improving teachers’ skills to detect mathematical and scientific talent in elementary school students. Within the project, teachers from 23 German schools and researchers cooperate to extend teachers’ diagnostic competencies, substantiate their practices scientifically, and to learn from each other’s experiences in the detection and promotion of STEM talent (i.e. networked improvement community). The project is theoretically based on domain- specific talent development models for mathematics and natural science. In the course of the project, teachers interact with e-learning modules, participate in training sessions, attend workshops that bridge scientific theory and educational practice, and regularly evaluate these components of the project. We present the conceptualization of the project as well as first results. [less ▲]

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See detailPerformance Analysis of Cell-Free Massive MIMO Systems: A Stochastic Geometry Approach
Papazafeiropoulos, Anastasios; Kourtessis, Pandelis; Di Renzo, Marco et al

in IEEE Transactions on Vehicular Technology (2020)

Cell-free (CF) massive multiple-input-multiple-output (MIMO) has emerged as an alternative deployment for conventional cellular massive MIMO networks. As revealed by its name, this topology considers no ... [more ▼]

Cell-free (CF) massive multiple-input-multiple-output (MIMO) has emerged as an alternative deployment for conventional cellular massive MIMO networks. As revealed by its name, this topology considers no cells, while a large number of multi-antenna access points (APs) serves simultaneously a smaller number of users over the same time/frequency resources through time-division duplex (TDD) operation. Prior works relied on the strong assumption (quite idealized) that the APs are uniformly distributed, and actually, this randomness was considered during the simulation and not in the analysis. However, in practice, ongoing and future networks become denser and increasingly irregular. Having this in mind, we consider that the AP locations are modeled by means of a Poisson point process (PPP) which is a more realistic model for the spatial randomness than a grid or uniform deployment. In particular, by virtue of stochastic geometry tools, we derive both the downlink coverage probability and achievable rate. Notably, this is the only work providing the coverage probability and shedding light on this aspect of CF massive MIMO systems. Focusing on the extraction of interesting insights, we consider small-cells (SCs) as a benchmark for comparison. Among the findings, CF massive MIMO systems achieve both higher coverage and rate with comparison to SCs due to the properties of favorable propagation, channel hardening, and interference suppression. Especially, we showed for both architectures that increasing the AP density results in a higher coverage which saturates after a certain value and increasing the number of users decreases the achievable rate but CF massive MIMO systems take advantage of the aforementioned properties, and thus, outperform SCs. In general, the performance gap between CF massive MIMO systems and SCs is enhanced by increasing the AP density. Another interesting observation concerns that a higher path-loss exponent decreases the rate while the users closer to the APs affect more the performance in terms of the rate. [less ▲]

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See detailRAPPORT ANNUEL SUR LES MIGRATIONS ET L'ASILE Luxembourg 2019
Sommarribas, Adolfo UL; Hallack, Florence UL; Rozenberga, Zane UL et al

Report (2020)

Le présent rapport trace les principaux développements et débats relatifs à la migration et à l'asile au Luxembourg en 2019. Le Luxembourg reste un pays d'immigration important, comme en témoignent les ... [more ▼]

Le présent rapport trace les principaux développements et débats relatifs à la migration et à l'asile au Luxembourg en 2019. Le Luxembourg reste un pays d'immigration important, comme en témoignent les chiffres du solde migratoire, qui reste la principale raison de la croissance démographique de la population résidente luxembourgeoise. L'immigration nette de ressortissants de pays tiers reste élevée (7 336) et dépasse celle des citoyens de l'Union européenne (UE; 4 806). Le nombre de personnes demandant une protection internationale est resté élevé en 2019 (2 047 demandes) par rapport aux niveaux enregistrés avant la «crise migratoire» (1 091 en 2014). Le regroupement familial reste la principale raison pour laquelle les ressortissants de pays tiers immigrent au Luxembourg, suivi des raisons économiques et de la protection internationale. Plusieurs développements majeurs se sont produits dans le domaine de la migration légale. L'introduction d'un nouveau visa de longue durée simplifie l'entrée et le séjour des ressortissants de pays tiers pour une période pouvant aller jusqu'à un an, sans avoir à demander un permis de séjour. Afin de garantir les droits des citoyens britanniques travaillant et résidant au Luxembourg avant le retrait du Royaume-Uni (UK) de l'UE (Brexit), quatre lois ont été adoptées, la plupart d'entre elles étant censées entrer en vigueur en cas d’un Brexit sans accord. D'autres changements importants liés à la migration résultent de l'adoption de la loi du 4 décembre 2019 modifiant la loi du 29 août 2009 sur la libre circulation des personnes et l'immigration. Cette loi prend en compte les commentaires de l'expert lors de l'évaluation en 2016 de l'application de Schengen. [less ▲]

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See detailMechanisms of neurodegeneration in Parkinson’s disease: keep neurons in the PINK1
Brunelli, Francesco UL; Valente, Enza Maria; Arena, Giuseppe UL

in Mechanisms of Ageing and Development (2020)

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See detailOn Dantzig and Lasso estimators of the drift in a high dimensional Ornstein-Uhlenbeck model
Ciolek, Gabriela UL; Marushkevych, Dmytro UL; Podolskij, Mark UL

in Electronic Journal of Statistics (2020), 14(2), 4395-4420

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See detailLUPE – Leistung unterstützen, Potenziale entdecken. Ein Projekt zur materialgestützten Förderung diagnostischer Fähigkeiten von Grundschullehrpersonen im Mathematik- und Sachunterricht
Krischler, Mireille UL; Breit, Moritz; Mack, Elena et al

in Weigand, Gabriele; Fischer, Christian; Käpnick, Friedhelm (Eds.) et al Leistung macht Schule: Förderung leistungsstarker und potenziell besonders leistungsfähiger Schülerinnen und Schüler (2020)

Zur Unterstützung der Entwicklung leistungsstarker und potenziell besonders leistungsfähiger Schülerinnen und Schüler setzt das LemaS-Teilprojekt 20 LUPE bei den diagnostischen Kompetenzen der ... [more ▼]

Zur Unterstützung der Entwicklung leistungsstarker und potenziell besonders leistungsfähiger Schülerinnen und Schüler setzt das LemaS-Teilprojekt 20 LUPE bei den diagnostischen Kompetenzen der Lehrpersonen an. Basis hierfür ist ein Talententwicklungsmodell mit spezifischem Bezug zur Leistungsentwicklung in den MINT-Fächern (Mathematik und Sachunterricht – Bereich Natur & Technik) während der Grundschulzeit. Dieses Modell wird im LUPE-Projekt entwickelt, indem die Perspektiven von Wissenschaft und Praxis nutzbringend zusammengebracht und integriert werden. Aufbauend auf dem Talententwicklungsmodell werden fachspezifische Materialen entwickelt, in der Praxis erprobt und formativ evaluiert. Diese Materialien sollen Grundschullehrpersonen in den MINT-Fächern dabei unterstützen, aktiv und strukturiert Leistungspotenziale bei ihren Schülerinnen und Schülern zu suchen und zu finden – Strategien der psychologischen Diagnostik ergänzen die pädagogische Diagnostik im Schulalltag. Die Materialien, die von den Lehrpersonen im Unterricht flexibel eingesetzt werden können, kombinieren unterschiedliche Ansätze wie Verhaltensbeobachtungsmethoden, Interviews und diagnostisches Aufgabenmaterial. Es ist zu erwarten, dass das LUPE-Projekt die diagnostischen Fähigkeiten von Grundschullehrpersonen zur Erkennung (potenziell) leistungsstarker Schülerinnen und Schüler erhöht: Ihre Beobachtungsfähigkeit wird geschult und ihre Aufmerksamkeit auf alle Schülerinnen und Schüler gelenkt – und damit auch auf potenziell besonders leistungsfähige Schülerinnen und Schüler, die ansonsten eher unterschätzt oder übersehen werden. Zudem wird der Unterricht um Situationen angereichert, in denen Potenzial gezeigt und erkannt werden kann. [less ▲]

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See detailDelay Constrained Resource Allocation for NOMA Enabled Satellite Internet of Things with Deep Reinforcement Learning
Yan, Xiaojuan; An, Kang; Zhang, Qianfeng et al

in IEEE Internet of Things Journal (2020)

With the ever increasing requirement of transferring data from/to smart users within a wide area, satellite internet of things (S-IoT) networks has emerged as a promising paradigm to provide cost ... [more ▼]

With the ever increasing requirement of transferring data from/to smart users within a wide area, satellite internet of things (S-IoT) networks has emerged as a promising paradigm to provide cost-effective solution for remote and disaster areas. Taking into account the diverse link qualities and delay qualityof- service (QoS) requirements of S-IoT devices, we introduce a power domain non-orthogonal multiple access (NOMA) scheme in the downlink S-IoT networks to enhance resource utilization efficiency and employ the concept of effective capacity to show delay-QoS requirements of S-IoT traffics. Firstly, resource allocation among NOMA users is formulated with the aim of maximizing sum effective capacity of the S-IoT while meeting the minimum capacity constraint of each user. Due to the intractability and non-convexity of the initial optimization problem, especially in the case of large-scale user-pair in NOMA enabled S-IoT. This paper employs a deep reinforcement learning (DRL) algorithm for dynamic resource allocation. Specifically, channel conditions and/or delay-QoS requirements of NOMA users are carefully selected as state according to exact closed-form expressions as well as low-SNR and high-SNR approximations, a deep Q network is first adopted to yet reward and output the optimum power allocation coefficients for all users, and then learn to adjust the allocation policy by updating the weights of neural networks using gained experiences. Simulation results are provided to demonstrate that with a proper discount factor, reward design, and training mechanism, the proposed DRL based power allocation scheme can output optimal/near-optimal action in each time slot, and thus, provide superior performance than that achieved with a fixed power allocation strategy and orthogonal multiple access (OMA) scheme. [less ▲]

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