Quantization of spectral curves and DQ-modules

in Journal of Noncommutative Geometry (2018)

Given an holomorphic Higgs bundle on a compact Riemann surface of genus greater than one, we prove the existence of an holonomic DQ-module supported by the spectral curve associated to this bundle. Then ... [more ▼]

Given an holomorphic Higgs bundle on a compact Riemann surface of genus greater than one, we prove the existence of an holonomic DQ-module supported by the spectral curve associated to this bundle. Then, we relate quantum curves arising in various situations (quantization of spectral curves of Higgs Bundles, quantization of the A-polynomial...) to DQ-modules and show that a quantum curve and the DQ-module canonically associated to it have isomorphic sheaves of solutions. [less ▲]

Language influence on ninth-graders’ mathematics performance in a multilingual educational setting

Scientific Conference (2018, December 16)

Attracting and retaining international students in the EU (Country report Luxembourg)

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 ▲]

Etude qualitative par entretiens sur l'enseignement du français au Luxembourg

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

Lesegewohnheiten und bilinguale Lesekompetenzen - Zum Zusammenhang zwischen den Deutsch- und Französisch-Lesekompetenzen von Neuntklässlerinnen und Neuntklässlern und ihren außerschulischen Lesegewohnheiten in Luxemburg

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 ▲]

Habitudes de lecture et compétences de lecture bilingue

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 ▲]

The German Acton Improving Law Enforcement on Social NEtworks (NetzDG): A Blunt Sword?

E-print/Working paper (2018)

The Paradoxical Case Against Interest Rate Caps for Microfinance - And: How Fintech and RegTech Resolve The Dilemma

Speeches/Talks (2018)

Übergangsentscheidungen in Luxemburg – Die Passung zwischen Leistungs- und Anforderungsniveau und deren Relation zum späteren Lernerfolg

in LUCET; SCRIPT (Eds.) Nationaler Bildungsbericht Luxemburg 2018 (2018)

Nonlinear Approximations in Cryptanalysis Revisited

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 ▲]