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See detailh- and p-adaptivity driven by recovery and residual-based error estimators for PHT-splines applied to time-harmonic acoustics
Videla, Javier; Anitescu, Cosmin; Khajah, Tahsin et al

in Computers and Mathematics with Applications (2018), 77(9), 2369-2395

In this work, we demonstrate the application of PHT-splines for time-harmonic acoustic problems, modeled by the Helmholtz equation. Solutions of the Helmholtz equation have two features: global ... [more ▼]

In this work, we demonstrate the application of PHT-splines for time-harmonic acoustic problems, modeled by the Helmholtz equation. Solutions of the Helmholtz equation have two features: global oscillations associated with the wave number and local gradients caused by geometrical irregularities. We show that after a sufficient number of degrees of freedom is used to approximate global oscillations, adaptive refinement can capture local features of the solution. We compare residual-based and recovery-based error estimators and investigate the performance of -refinement. The simulations are done in the context of recently introduced Geometry Independent Field approximaTion (GIFT), where PHT-splines are only used to approximate the solution, while the computational domain is parameterized with NURBS. This approach builds on the natural adaptation ability of PHT-splines and avoids the re-parameterization of the NURBS geometry during the solution refinement process. [less ▲]

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See detailAttracting and retaining international students in the EU (Country report Luxembourg)
Petry, Ralph UL; Coda, Nicolas UL; Sommarribas, Adolfo UL et al

Report (2018)

Unlike many other EU Member States, the higher education system in Luxembourg is marked by a particular characteristic, namely the fact that the University of Luxembourg is the only public university in ... [more ▼]

Unlike many other EU Member States, the higher education system in Luxembourg is marked by a particular characteristic, namely the fact that the University of Luxembourg is the only public university in the country. Established by law in 2003, the University of Luxembourg is therefore the main actor in the higher education system and hosts the large majority of international students in Luxembourg. In addition to the University of Luxembourg, two more types of institutions complement the higher education system in Luxembourg and are recognised by the Ministry of Higher Education and Research as higher education institutions (hereafter referred to as ‘HEIs’), namely: 1. Secondary educational institutions offering educational programmes that award an advanced technician’s certificate (‘Brevet de technicien supérieur’ – ‘BTS’); 2. Private foreign universities having infrastructures or campus in Luxembourg. In order to be able to award higher education diplomas as well as to host international students, all HEIs are mandatorily required to be approved by the Ministry of Higher Education and Research, with the exception of the University of Luxembourg because it was established by law. The admission conditions for international students to study at a HEI in Luxembourg are twofold: First, the international student must apply and be accepted at an approved HEI or at the University of Luxembourg. Second, once accepted at a HEI, s/he needs to apply for a temporary authorisation of stay, and subsequently, if applicable, a Visa D (valid for 3 months), from his/her country of origin before being authorised to travel to Luxembourg and before being issued a ‘student’ residence permit (valid for minimum 1 year and renewable) in Luxembourg. To conclude, the HEIs in Luxembourg, under the overall auspice of the Ministry of Higher Education and Research, as well as the immigration authorities are the main stakeholders in the context of international students studying in Luxembourg. Luxembourg transposed the Directive (EU) 2016/801 by the Law of 1 August 2018, which amended the amended ‘Immigration Law’ and entered into force on 21 September 2018. In this context, the study highlights in particular the introduction of a new residence permit for ‘private reasons’ in view of seeking employment or establishing a business in Luxembourg. This residence permit was newly introduced by the transposition of the Directive and allows international graduates to remain in the country for a maximum duration of nine months in order to find a job or establish a business in relation to their academic training. Prior to the transposition, international students were only able to change their immigration status to ‘salaried worker’ immediately after their graduation. Moreover, the transposition modified a number of legal dispositions, such as the increase of the maximum amount of hours that students are authorised to work, from 10 hours to 15 hours per week. Furthermore, Bachelor students enrolled in their first year of academic studies as well as students enrolled in a study programme awarding them a ‘BTS’ are no longer excluded from exercising a salaried activity as allowed by law. Lastly, the transposition also facilitates the intra-European mobility of international students who follow a European or multilateral programme that contains mobility measures or a convention between two or more HEIs. The attraction and retention of international students are not considered as a national political priority per se by the Luxembourgish authorities, but have to be perceived in an overall national political priority of attracting “talents” to Luxembourg, i.e. (highly) qualified persons, regardless of their nationality and in the interest of the country and its economy. The stakeholders consulted in the context of this study identified several factors that may have positive effects on the attraction and retention of international students. These include, among others: - the geographical position of Luxembourg with an important financial sector and several European institutions - the multilingual environment of the country as well as the University of Luxembourg - the HEI ranking of the University of Luxembourg - the comparatively low levels of tuition fees, particularly of the national public HEIs - the fact that the level tuition fees is the same for every student, no matter his/her nationality, with the exception of examples from private HEIs Furthermore, the consulted stakeholders identified several examples of good practices in the context of this study, such as for example: - A close and diligent collaboration between all stakeholders, in particular between the Directorate of Immigration, the Ministry of Higher Education and Research and the University of Luxembourg - Quality management of private HEI (mainly through the approval procedure) in view of the best interest of students - Affordable tuitions fees in the higher education system At the same time, the consulted stakeholders have identified several challenges, such as: - the languages of instruction (with a strong emphasis on French and German especially at the Bachelor/‘BTS’ levels) and the primary working languages (French and Luxembourgish) - socio-economic factors, particularly the high costs of living and the challenge of finding affordable housing - authenticity and veracity of transmitted diplomas in the context of a diploma recognition - a challenging procedure related to the entrance exam for international students who hold a high school diploma issued in a country that is not a signatory country of Paris/Lisbon conventions - potential misuse of the ‘student’ residence permit in view of trying to stay in the country instead of succeeding in the studies. In addition to the major legislative change introduced by the transposition of the Directive and the various factors and challenges mentioned above, the study also highlights a number of initiatives, offered in particular by the University of Luxembourg, aiming to support international students after their graduation and to encourage them to establish and/or maintain a connection to the national labour market. The study concludes with a section on bilateral and multilateral cooperation with third countries, both at the level of the Luxembourgish State as well as at the level of HEIs, particularly of the University of Luxembourg. [less ▲]

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See detailEtude qualitative par entretiens sur l'enseignement du français au Luxembourg
Morys, Nancy UL

in Lenz, Thomas; Baumann, Isabell; Küpper, Achim (Eds.) Rapport national sur l'éducation au Luxembourg (2018)

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See detailOn solutions to estimating equations and the empirical saddlepoint approximation of their distribution
Holcblat, Benjamin UL; Sowell, Fallaw

Scientific Conference (2018, December 15)

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See detailDigitalisierung von Organisationen: Was ist eine digitale Strategie?
Rohles, Björn UL

Article for general public (2018)

Digital transformation profoundly changes how organizations work. This is why organizations need a digital strategy. But what exactly is a digital strategy? And which aspects should it consider?

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See detailInklusive Bildung aus der Sicht luxemburgischer Grundschullehrerinnen und -lehrer
Pit-Ten Cate, Ineke UL; Krischler, Mireille UL

in Lenz, Thomas; Baumann, Isabell; Küpper, Achim (Eds.) Nationaler Bildungsbericht Luxemburg 2018 (2018)

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See detailÜbergangsentscheidungen in Luxemburg – Die Passung zwischen Leistungs- und Anforderungsniveau und deren Relation zum späteren Lernerfolg
Hörstermann, Thomas UL; Pit-Ten Cate, Ineke UL; Krolak-Schwerdt, Sabine UL

in Lenz, Thomas; Baumann, Isabell; Küpper, Achim (Eds.) Nationaler Bildungsbericht Luxemburg 2018 (2018)

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See detailL’éducation inclusive du point de vue du personnel de l’enseignement fondamental luxembourgeois
Pit-Ten Cate, Ineke UL; Krischler, Mireille UL

in Lenz, Thomas; Baumann, Isabell; Küpper, Achim (Eds.) Rapport Ntional sur l´Éducation au Luxembourg 2018 (2018)

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See detailSchülerkompetenzen im Längsschnitt - Die Entwicklung von Deutsch-Leseverstehen und Mathematik in Luxemburg zwischen der 3. und 9. Klasse
Sonnleitner, Philipp UL; Krämer, Charlotte UL; Gamo, Sylvie UL et al

Report (2018)

it der Erhebung der ÉpStan im Herbst 2016 liegt erstmalig ein Datensatz vor, der einen Einblick in die Entwicklung schulischer Kompetenzen zwischen der 3. Schulstufe (Zyklus 3.1) und der 9. Schulstufe (5e ... [more ▼]

it der Erhebung der ÉpStan im Herbst 2016 liegt erstmalig ein Datensatz vor, der einen Einblick in die Entwicklung schulischer Kompetenzen zwischen der 3. Schulstufe (Zyklus 3.1) und der 9. Schulstufe (5e bzw. 9e) erlaubt. Das vorliegende Kapitel gibt nun einen ersten Einblick in die längsschnittliche Kompetenzentwicklung in den Bereichen Deutsch-Leseverstehen und Mathematik. Hierfür werden die Testergebnisse der untersuchten Schülerkohorte aus den ÉpStan 2010 in der 3. Schulstufe (Zyklus 3.1) den Leistungen in der 9. Schulstufe (5e bzw. 9e) im Jahre 2016 gegenübergestellt. [less ▲]

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See detailLesegewohnheiten und bilinguale Lesekompetenzen - Zum Zusammenhang zwischen den Deutsch- und Französisch-Lesekompetenzen von Neuntklässlerinnen und Neuntklässlern und ihren außerschulischen Lesegewohnheiten in Luxemburg
Reichert, Monique UL; Krämer, Charlotte UL; Wollschläger, Rachel UL et al

Report (2018)

Der Beitrag widmet sich der Frage, ob die Unterschiede hinsichtlich der Lesehäufigkeit, der Textsorten, die von Jugendlichen in ihrer Freizeit rezipiert werden, und der Sprache, in der sie bevorzugt lesen ... [more ▼]

Der Beitrag widmet sich der Frage, ob die Unterschiede hinsichtlich der Lesehäufigkeit, der Textsorten, die von Jugendlichen in ihrer Freizeit rezipiert werden, und der Sprache, in der sie bevorzugt lesen, dabei helfen können, ihr Lesekompetenz Niveau im Deutschen und Französischen – jenseits von sozioökonomischem Status, Migrationshintergrund, Muttersprache und Geschlecht – zu erklären. [less ▲]

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See detailHabitudes de lecture et compétences de lecture bilingue
Reichert, Monique UL; Krämer, Charlotte UL; Wollschläger, Rachel UL et al

Report (2018)

La problématique soulevée dans cet article concerne les liens entre d’une part, la fréquence de lecture chez les adolescents en fonction des types de textes lus, et de la langue dans laquelle ils lisent ... [more ▼]

La problématique soulevée dans cet article concerne les liens entre d’une part, la fréquence de lecture chez les adolescents en fonction des types de textes lus, et de la langue dans laquelle ils lisent et, dautre part, leur niveau de compétence de lecture en allemand et en français. En outre, il s’agit d’étudier ces liens en fonction des contextes socio-économique et migratoire, de la langue maternelle, et du sexe des adolescents. À cet effet, les données recueillies dans le cadre des Épreuves Standardisées (ÉpStan) de novembre 2016 permettent d’analyser les compétences de lecture en allemand et en français ainsi que les habitudes de lecture extrascolaire de 5177 élèves du grade 9, fréquentant l’Enseignement Secondaire (ES), l’Enseignement Secondaire Technique (EST) ou la branche Préparatoire de l’Enseignement Secondaire Technique (EST-PRE). Les analyses montrent clairement que, indépendamment du sexe, du type d’enseignement et des caractéristiques socioculturelles des adolescents, principalement la tendance à lire des textes narratifs est positivement corrélée aux compétences en lecture. [less ▲]

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See detailTemporal enhancer profiling of parallel lineages identifies AHR and GLIS1 as regulators of mesenchymal multipotency
Gerard, Déborah UL; Schmidt, Florian; Ginolhac, Aurélien UL et al

in Nucleic Acids Research (2018)

Temporal data on gene expression and context-specific open chromatin states can improve identification of key transcription factors (TFs) and the gene regulatory networks (GRNs) controlling cellular ... [more ▼]

Temporal data on gene expression and context-specific open chromatin states can improve identification of key transcription factors (TFs) and the gene regulatory networks (GRNs) controlling cellular differentiation. However, their integration remains challenging. Here, we delineate a general approach for data-driven and unbiased identification of key TFs and dynamic GRNs, called EPIC-DREM. We generated time-series transcriptomic and epigenomic profiles during differentiation of mouse multipotent bone marrow stromal cell line (ST2) toward adipocytes and osteoblasts. Using our novel approach we constructed time-resolved GRNs for both lineages and identifed the shared TFs involved in both differentiation processes. To take an alternative approach to prioritize the identified shared regulators, we mapped dynamic super-enhancers in both lineages and associated them to target genes with correlated expression profiles. The combination of the two approaches identified aryl hydrocarbon receptor (AHR) and Glis family zinc finger 1 (GLIS1) as mesenchymal key TFs controlled by dynamic cell type-specific super-enhancers that become repressed in both lineages. AHR and GLIS1 control differentiation-induced genes and their overexpression can inhibit the lineage commitment of the multipotent bone marrow-derived ST2 cells. [less ▲]

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See detailEen haarde Brexit gëtt ëmmer méi wahrscheinlech
Högenauer, Anna-Lena UL

Article for general public (2018)

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See detailNonlinear Approximations in Cryptanalysis Revisited
Beierle, Christof UL; Canteaut, Anne; Leander, Gregor

in IACR Transactions on Symmetric Cryptology (2018), 2018(4), 80-101

This work studies deterministic and non-deterministic nonlinear approximations for cryptanalysis of block ciphers and cryptographic permutations and embeds it into the well-understood framework of linear ... [more ▼]

This work studies deterministic and non-deterministic nonlinear approximations for cryptanalysis of block ciphers and cryptographic permutations and embeds it into the well-understood framework of linear cryptanalysis. For a deterministic (i.e., with correlation ±1) nonlinear approximation we show that in many cases, such a nonlinear approximation implies the existence of a highly-biased linear approximation. For non-deterministic nonlinear approximations, by transforming the cipher under consideration by conjugating each keyed instance with a fixed permutation, we are able to transfer many methods from linear cryptanalysis to the nonlinear case. Using this framework we in particular show that there exist ciphers for which some transformed versions are significantly weaker with regard to linear cryptanalysis than their original counterparts. [less ▲]

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See detailData Exchange Interoperability in IoT Ecosystem for Smart Parking and EV Charging
Karpenko, Anastasiia; Kinnunen, Tuomas; Madhikermi, Manik et al

in Sensors (2018)

Many domains are trying to integrate with the Internet of Things (IoT) ecosystem, such as public administrations starting smart city initiatives all over the world. Cities are becoming smart in many ways ... [more ▼]

Many domains are trying to integrate with the Internet of Things (IoT) ecosystem, such as public administrations starting smart city initiatives all over the world. Cities are becoming smart in many ways: smart mobility, smart buildings, smart environment and so on. However, the problem of non-interoperability in the IoT hinders the seamless communication between all kinds of IoT devices. Different domain specific IoT applications use different interoperability standards. These standards are usually not interoperable with each other. IoT applications and ecosystems therefore tend to use a vertical communication model that does not allow data sharing horizontally across different IoT ecosystems. In 2014, The Open Group published two domain-independent IoT messaging standards, O-MI and O-DF, aiming to solve the interoperability problem. In this article we describe the practical use of O-MI/O-DF standards for reaching interoperability in a mobile application for the smart city context, in particular for the Smart Mobility domain, electric vehicle (EV) charging case study. The proof-of-concept of the smart EV charging ecosystem with mobile application user interface was developed as a part of an EU (Horizon 2020) Project bIoTope. [less ▲]

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See detailSymbol-Level Precoding for Low Complexity Transmitter Architectures in Large-Scale Antenna Array Systems
Domouchtsidis, Stavros; Tsinos, Christos UL; Chatzinotas, Symeon UL et al

in IEEE Transactions on Wireless Communications ( Early Access ) (2018)

In this paper we consider three transmitter designs for symbol-level-precoding (SLP), a technique that mitigates multiuser interference (MUI) in multiuser systems by designing the transmitted signals ... [more ▼]

In this paper we consider three transmitter designs for symbol-level-precoding (SLP), a technique that mitigates multiuser interference (MUI) in multiuser systems by designing the transmitted signals using the Channel State Information and the information-bearing symbols. The considered systems tackle the high hardware complexity and power consumption of existing SLP techniques by reducing or completely eliminating fully digital Radio Frequency (RF) chains. The first proposed architecture referred as, Antenna Selection SLP, minimizes the MUI by activating a subset of the available antennas and thus, reducing the number of required RF chains to the number of active antennas. In the other two architectures, which we refer to as RF domain SLP, the processing happens entirely in the RF domain, thus eliminating the need for multiple fully digital RF chains altogether. Instead, analog phase shifters directly modulate the signals on the transmit antennas. The precoding design for all the considered cases is formulated as a constrained least squares problem and efficient algorithmic solutions are developed via the Coordinate Descent method. Simulations provide insights on the power efficiency of the proposed schemes and the improvements over the fully digital counterparts. [less ▲]

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See detailTeacher expectations concerning students with immigrant background or special educational needs
Pit-Ten Cate, Ineke UL; Glock, Sabine UL

in Educational Research and Evaluation (2018)

Male students with immigrant backgrounds are disproportionally referred for special educational support outside regular classrooms or schools, which may reflect differential teachers´ expectations ... [more ▼]

Male students with immigrant backgrounds are disproportionally referred for special educational support outside regular classrooms or schools, which may reflect differential teachers´ expectations concerning the academic achievement of students based on socio-demographic characteristics. Although research has indicated differential teachers´ expectations for students based on immigrant background or special educational needs (SEN), less is known about a possible double vulnerability associated with combined stereotypes. Therefore, in the current study both SEN and immigrant background were systematically varied and teachers were asked to rate the students´ academic achievement. Results show that teachers´ expectations of students with SEN and immigrant background was lower than for students without immigrant background, especially in regards to language proficiency. These results may help to explain the overrepresentation of students with immigrant background in special educational programs. The educational and theoretical implications of these findings are discussed. [less ▲]

Detailed reference viewed: 98 (8 UL)