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See detailThe Cab Rank Rule: English Barristers in Foreign Courts
Happold, Matthew UL

in New Law Journal (2021)

When the cab rank rule is no longer a defense: considerations when accepting instructions overseas. Barristers have hit the headlines recently for taking instructions on controversial cases in foreign ... [more ▼]

When the cab rank rule is no longer a defense: considerations when accepting instructions overseas. Barristers have hit the headlines recently for taking instructions on controversial cases in foreign jurisdictions, to which the cab rank rule obliging a barrister to accept any work does not apply. When accepting such cases, barristers should bear in mind whether those foreign proceedings are at odds with their core duties under the Bar Standard Board’s Code of Conduct, particularly in politically sensitive cases. [less ▲]

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See detailMathematical modeling of thermal behavior of single iron ore pellet during heat hardening oxidation
Amani, Hafez; Alamdari, E.K; Ale Ebrahim, H. et al

in Journal of Thermal Analysis and Calorimetry (2021)

In this study, a one-dimensional generic model capable of being integrated with reactor scale models is proposed for a single pellet through solving the transient diferential conservation equations ... [more ▼]

In this study, a one-dimensional generic model capable of being integrated with reactor scale models is proposed for a single pellet through solving the transient diferential conservation equations. Predicted results comparison with the experimental data showed close agreement. In addition, the model was used to investigate the relevance of physical characteristics of pellet, reacting gas composition, difusion factors, and prevailing regime. It was found that the pure magnetite pellet could achieve a temperature rise of about 245 K at oxygen concentration of 40 vol.%, whereas the maximum temperature diference inside the pellet was approximately 24 K. Moreover, increasing pellet size, the maximum attainable temperature reached a peak and then leveled out. Furthermore, by decreasing the pore diameter, the pellet size with peak temperature shifted to the smaller pellet sizes. Analyzing the numerical results also showed that for the small pellet sizes, shortening the difusion path leads to the spreading of the reaction interface. The modeling methodology herein can be applied to any particulate processes and is not limited to the aforementioned case. [less ▲]

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See detailPredictive QM/MM Modeling of Modulations in Protein–Protein Binding by Lysine Methylation
Sanim Rahman; Vered Wineman-Fisher; Yasmine Al-Hamdani et al

in Journal of Molecular Biology (2021)

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See detailThe Minor Order for Homomorphisms via Natural Dualities
Poiger, Wolfgang UL; Teheux, Bruno UL

Scientific Conference (2021, February 05)

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See detailAGILE FERTIGUNGSSTEUERUNG FÜR (RE-)FABRIKATIONSSYSTEME
Groß, Sebastian UL

Doctoral thesis (2021)

Increasing product variance and individualisation lead to increasing demands for flexibility in produc-tion and production control. In the context of remanufacturing, these demands are further intensified ... [more ▼]

Increasing product variance and individualisation lead to increasing demands for flexibility in produc-tion and production control. In the context of remanufacturing, these demands are further intensified by unknown conditions of the used products. Each product to be remanufactured may therefore require an individual route through the remanufacturing system. This process, which puts used products into an "as good as new or better" condition, is receiving increasing attention due to its high ecological and economic potential and legal regulations. In order to meet these requirements, a hybrid control archi-tecture will be presented. This consists of centralised and decentralised components. At the decentral-ised level, all physical production participants are networked with software components and controlled by these. These components can acquire the status and availability of the corresponding manufacturing participants. They can communicate with each other as well as with the central level. The central level is where the scheduling of machines and automated guided vehicle (AGVs) takes place. This is carried out simultaneously and not sequentially as is the case with the currently available control systems. A method based on Constraint Programming (CP) is being developed to optimise scheduling. Simulation results show that a simultaneous, as opposed to a sequential, scheduling enables a reduction of makespan by 35.6 %. Compared to other state of the art methods, the CP-based approach provides the best results and this in a significantly shorter computing time. The control architecture is able to react adequately to unexpected events such as machine failures or new orders. It uses real-life feedback from the shop floor for this purpose. The architecture is implemented as a multi-agent system. The approach can be validated by successfully controlling a model factory in a realistic environment. [less ▲]

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See detailRobin Samuel im Interview mit Contacto: Die Pandemie wird sich auf den Berufseinstieg, die Gesundheit und die psychologische Entwicklung der Jugendlichen auswirken
Höpner, Moritz UL

Article for general public (2021)

Contacto’s Paula Santos Ferreira has asked Prof. Dr. Robin Samuel for his views on the possible consequences of the current pandemic for Luxembourgish young people. Her recent article, citing the ... [more ▼]

Contacto’s Paula Santos Ferreira has asked Prof. Dr. Robin Samuel for his views on the possible consequences of the current pandemic for Luxembourgish young people. Her recent article, citing the preliminary results of the study Young People and COVID-19 (YAC+), is aimed at a large Portuguese-speaking readership in Luxembourg. [less ▲]

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See detailEuropean Semester 2020-2021 country fiche on disability equality Luxembourg
Limbach-Reich, Arthur UL; Shahabi, Shafagh UL

Report (2021)

There is a great discrepancy between the omnipresent demands for inclusion published by official bodies and ministries and the actual participation of people with disabilities in social life. The policy ... [more ▼]

There is a great discrepancy between the omnipresent demands for inclusion published by official bodies and ministries and the actual participation of people with disabilities in social life. The policy cultivates the rhetoric of inclusion in programmatic and conceptual formulations, while at the same time maintaining or even expanding separative institutions for those that are considered not to be eligible for inclusion in the fields of education and employment (see competence centres in education and ‘inclusion’ in sheltered workshops, or the persistent exclusion of persons under guardianship from the right to vote). Inclusion is viewed primarily from an economic and neo-liberal perspective, without questioning the basic principles of a meritocratic society oriented towards proven performance. Performance appraisals, especially in the area of education and work, are largely based on the performance demanded and shown without sufficiently taking into account the way the performance is achieved. In the educational sector, the incompatibility of introducing educational standards and achieving full inclusion is not recognised. Separating establishments are renamed to inclusive settings without any fundamental reorientation. The former regional special schools for pupils with cognitive impairments were re-branded as competence centres for intellectual development. With the introduction of the competence centres, no longer official figures are published regarding pupils who are taught separately. There are also no official figures on how many pupils were assigned to the competence centres from regular schools and vice versa. It is therefore impossible to give comparative statistical evidence of the extent to which inclusive education has currently developed in Luxembourg. With regard to employment, the same problems remain as those already identified in the first Action Plan. People with disabilities experience considerable difficulty in finding a job in the mainstream labour market. Unemployment is disproportionately high among people with disabilities and lasts much longer than among job seekers without disabilities. People with disabilities are increasingly oriented towards working in a sheltered workshop under the national guidelines of the Employment Agency. The employment quotas for people with disabilities, which are legally mandated, are largely not met and are not monitored or imposed by the state. Also, some social problems already addressed in the first Action Plan have still not been tackled, such as the legal incapacity of people under guardianship. People with disabilities under guardianship are extensively excluded from self-determination and political participation. They may not vote nor may they run as candidates. As a result, almost 10 years after the introduction of the UN-CRPD no improvement has been made in this area. Furthermore, there are still problems in the implementation of the accessibility of buildings and infrastructure for public use. [less ▲]

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See detailLuxembourg in light of the OpenLux revelations
Pantazatou, Aikaterini UL

Speeches/Talks (2021)

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See detailCortical responses to letters and ambiguous speech vary with reading skills in dyslexic and typically reading children
Romanovska, Linda UL; Janssen, Roef; Bonte, Milene

in NeuroImage: Clinical (2021), 30

One of the proposed issues underlying reading difficulties in dyslexia is insufficiently automatized letter-speech sound associations. In the current fMRI experiment, we employ text-based recalibration to ... [more ▼]

One of the proposed issues underlying reading difficulties in dyslexia is insufficiently automatized letter-speech sound associations. In the current fMRI experiment, we employ text-based recalibration to investigate letter- speech sound mappings in 8–10 year-old children with and without dyslexia. Here an ambiguous speech sound /a?a/ midway between /aba/ and /ada/ is combined with disambiguating “aba” or “ada” text causing a perceptual shift of the ambiguous /a?a/ sound towards the text (recalibration). This perceptual shift has been found to be reduced in adults but not in children with dyslexia compared to typical readers. Our fMRI results show significantly reduced activation in the left fusiform in dyslexic compared to typical readers, despite comparable behavioural performance. Furthermore, enhanced audio-visual activation within this region was linked to better reading and phonological skills. In contrast, higher activation in bilateral superior temporal cortex was associated with lower letter-speech sound identification fluency. These findings reflect individual differences during the early stages of reading development with reduced recruitment of the left fusiform in dyslexic readers together with an increased involvement of the superior temporal cortex in children with less automatized letter-speech sound associations. [less ▲]

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See detailAktuelle Entwicklungen im Steuerrecht in der Informationstechnologie 2019/2020 - Teil 1
Sinnig, Julia UL; Schmittmann, Jens M.

in Kommunikation und Recht (2021), 24(2), 92-98

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See detailAVRNTRU: Lightweight NTRU-based Post-Quantum Cryptography for 8-bit AVR Microcontrollers
Cheng, Hao UL; Groszschädl, Johann UL; Roenne, Peter UL et al

in 2021 Design, Automation and Test in Europe Conference and Exhibition, DATE 2021, Grenoble, France, February 1-5, 2021, Proceedings (2021, February)

Introduced in 1996, NTRUEncrypt is not only one of the earliest but also one of the most scrutinized lattice-based cryptosystems and expected to remain secure in the upcoming era of quantum computing ... [more ▼]

Introduced in 1996, NTRUEncrypt is not only one of the earliest but also one of the most scrutinized lattice-based cryptosystems and expected to remain secure in the upcoming era of quantum computing. Furthermore, NTRUEncrypt offers some efficiency benefits over “pre-quantum” cryptosystems like RSA or ECC since the low-level arithmetic operations are less computation-intensive and, thus, more suitable for constrained devices. In this paper we present AVR N TRU, a highly-optimized implementation of NTRUEncrypt for 8-bit AVR microcontrollers that we developed from scratch to reach high performance and resistance to timing attacks. AVR N TRU complies with the EESS #1 v3.1 specification and supports product-form parameter sets such as ees443ep1, ees587ep1, and ees743ep1. An entire encryption (including mask generation and blinding-polynomial generation) using the ees443ep1 parameters requires 847973 clock cycles on an ATmega1281 microcontroller; the decryption is more costly and has an execution time of 1051871 cycles. We achieved these results with the help of a novel hybrid technique for multiplication in a truncated polynomial ring, whereby one of the operands is a sparse ternary polynomial in product form and the other an arbitrary element of the ring. A constant-time multiplication in the ring given by the ees443ep1 parameters takes only 192577 cycles, which sets a new speed record for the arithmetic part of a lattice-based cryptosystem on AVR. [less ▲]

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See detailTowards Optimal Energy Efficiency in Cell-Free Massive MIMO Systems
Papazafeiropoulos, A.; Ngo, H.Q.; Kourtessis, Pandelis et al

in IEEE Transactions on Green Communications and Networking (2021), 5(2), 816-831

Motivated by the ever-growing demand for green wireless communications and the advantages of cell-free (CF) massive multiple-input multiple-output (mMIMO) systems, we focus on the design of their downlink ... [more ▼]

Motivated by the ever-growing demand for green wireless communications and the advantages of cell-free (CF) massive multiple-input multiple-output (mMIMO) systems, we focus on the design of their downlink (DL) for optimal energy efficiency (EE). To address this fundamental topic, we assume that each access point (AP) is deployed with multiple antennas and serves multiple users on the same time-frequency resource while the APs are Poisson point process (PPP) distributed, which approaches realistically their opportunistic spatial randomness. Relied on tools from stochastic geometry, we derive a lower bound on the DL average achievable spectral efficiency (SE). Next, we consider a realistic power consumption model for CF mMIMO systems. These steps enable the formulation of a tractable optimization problem concerning the DL EE, which results in the analytical determination of the optimal pilot reuse factor, the AP density, and the number of AP antennas and users that maximize the EE. Hence, we provide useful design guidelines for CF mMIMO systems relating to fundamental system variables towards optimal EE. Among the results, we observe that an optimal pilot reuse factor and AP density exist, while larger values result in an increase of the interference, and subsequently, lower EE. Overall, it is shown that the CF mMIMO technology is a promising candidate for next-generation networks achieving simultaneously high SE and EE. [less ▲]

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See detailTowards Optimal Energy Efficiency in Cell-Free Massive MIMO Systems
Papazafeiropoulos, Anastasios; Ngo, Hien Quoc; Kourtessis, Pandelis et al

in IEEE Transactions on Green Communications and Networking (2021), 5(2), 816-831

Motivated by the ever-growing demand for green wireless communications and the advantages of cell-free (CF) massive multiple-input multiple-output (mMIMO) systems, we focus on the design of their downlink ... [more ▼]

Motivated by the ever-growing demand for green wireless communications and the advantages of cell-free (CF) massive multiple-input multiple-output (mMIMO) systems, we focus on the design of their downlink (DL) for optimal energy efficiency (EE). To address this fundamental topic, we assume that each access point (AP) is deployed with multiple antennas and serves multiple users on the same time-frequency resource while the APs are Poisson point process (PPP) distributed, which approaches realistically their opportunistic spatial randomness. Relied on tools from stochastic geometry, we derive a lower bound on the DL average achievable spectral efficiency (SE). Next, we consider a realistic power consumption model for CF mMIMO systems. These steps enable the formulation of a tractable optimization problem concerning the DL EE, which results in the analytical determination of the optimal pilot reuse factor, the AP density, and the number of AP antennas and users that maximize the EE. Hence, we provide useful design guidelines for CF mMIMO systems relating to fundamental system variables towards optimal EE. Among the results, we observe that an optimal pilot reuse factor and AP density exist, while larger values result in an increase of the interference, and subsequently, lower EE. Overall, it is shown that the CF mMIMO technology is a promising candidate for next-generation networks achieving simultaneously high SE and EE. [less ▲]

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See detailA Markov Chain Monte Carlo Approach for Estimating Daily Activity Patterns
Scheffer, Ariane Hélène Marie UL; Bandiera, Claudia UL; Cipriani, Ernesto et al

Scientific Conference (2021, February)

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See detailInvestigating heuristic algorithms for minimal controller location set problem in transportation networks
Mazur, Xavier UL; Rinaldi, Marco; Viti, Francesco UL

Scientific Conference (2021, February)

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See detailSensitivity Analysis on Regularity Based Driver Advisory Systems
Laskaris, Georgios; Seredynski, Marcin; Viti, Francesco UL

Scientific Conference (2021, February)

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See detailWorking towards responsive science education pedagogies during a time of crisis: centering community, diversity and access
Te Heesen, Kerstin UL; Siry, Christina UL; de Albuquerque Trigo, Maiza UL et al

Scientific Conference (2021, January 30)

Children, teachers, and families internationally are navigating new terrains of remote learning and teaching during the COVID-19 crisis, and this extends to the University of Luxembourg's SciTeach Center ... [more ▼]

Children, teachers, and families internationally are navigating new terrains of remote learning and teaching during the COVID-19 crisis, and this extends to the University of Luxembourg's SciTeach Center team, a multidisciplinary group of educators and researchers dedicated to supporting primary and pre-primary science education. Luxembourg’s schools closed mid-March 2020, with rapid implementation of online/distance schooling. By mid-May, the national scenario started changing with deconfinement stages, and schools adopted blended in-person/distance structure of rotating “A” and “B” weeks of instruction, ending the year with two weeks of “back to normal”. What are we wondering about? The SciTeach team responded to changing circumstances with several initiatives to support science education within new structures. The team’s interactions in response to the pandemic and resulting outcomes are the focus of a case study utilizing ethnographic methods and discourse analysis. We are examining planning discussions and development of remote science education resources for in-service teachers, children, and caregivers, with a purpose of identifying essential steps in the process, and the resulting impacts of changes. Why is this wondering important? This wondering will elaborate an adaptation process as we transitioned to online modes of interacting, reflecting on the applicability of responsive pedagogies during crisis. This crisis has exposed issues of equity and access, in particular with the high percentage of students who do not speak the languages of instruction at home (more than half) and has given rise to questions about what structural changes will/can remain ahead. As our main goal is to support children’s engagement in science, we discuss benefits and challenges associated with these responses as they were developed not with the intent to only respond, but to offer teachers a sustainable approach to support students in engaging in science moving forward. What approaches frame our thinking? Grounded in sociocultural theoretical perspectives (Sewell, 1999), we understand the teaching-learning processes as cultural enactment, and we draw on translanguaging perspectives (García, 2009) and multimodal approaches (Kress, 2004). Our theoretical and methodological approach is grounded as bricolage (Kincheloe, 2001), and we hope to honor the diversity and complexity of engaging in research with participants. We seek to trouble the existing policy-based notions of science "proficiency" as we consider diverse ways teachers, students, and families engage in science education, with a particular focus on examining issues of equity and access during crisis. Why is our wondering important to equity, diversity and / or social justice in science education? The overarching purpose of this work is identifying the adaptation process and reflecting upon the resulting impacts of changes. Issues of access and equity are multiple, for teachers, children, and caregivers, and our wondering focuses on three questions: • How can we work towards resource-rich approaches for working with students – to build on what they know and wonder – and make openings for engaging in science inquiry? • How can we support equitable student access to science, given the range of languages and technology access? • How can we keep and nurture community during times of rapid unplanned changes, and shifting interaction structures? [less ▲]

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See detailTight-binding perspective on excitons in hexagonal boron nitride
Galvani, Thomas UL

Doctoral thesis (2021)

Two dimensional materials, which are systems composed of one or several angstrom-thin layers of atoms, have recently received considerable attention for their novel electronic and optical properties. In ... [more ▼]

Two dimensional materials, which are systems composed of one or several angstrom-thin layers of atoms, have recently received considerable attention for their novel electronic and optical properties. In such systems, the quasi two dimensional confinement of electrons as well as the reduced dielectric screening lead to a strong binding of electrons and holes. These bound electron-hole excitations, termed excitons, control many of the peculiar opto-electronic properties of 2D materials. In this context we study hexagonal Boron Nitride (hBN) as a prototypical 2D system. hBN layers crystallize in a honeycomb lattice similar to graphene, with carbon atoms replaced by boron and nitrogen. Contrary to its carbon cousin, hBN is a wide band gap semiconductor, well know for its UV luminescence properties and its particularly strong excitons. We investigate theoretically the excitonic properties of single and multilayer hBN. To describe excitons, we make use of the Bethe-Salpeter equation, which provides an effective hamiltonian for electron-hole pairs. We show that, owing to the relatively simple electronic structure of BN systems, it is possible there to construct a model that approximately maps the Bethe-Salpeter equation onto an effective tight-binding Hamiltonian with few parameters, which are in turn fitted to ab initio calculations. Using this technique, we are able to study in detail the excitonic series in single layer hBN. We classify its excitons according to the symmetries of the point group of the crystal lattice, and thus provide precise optical selection rules. Because our model naturally preserves the crystal geometry, we are able to characterize the effects of the lattice, and show how their inclusion affects the excitonic and, in turn, optical properties of hBN compared to a continuum hydrogenoid model. Further, we can access exciton dispersion, which is a crucial component for the understanding of indirect processes. We thus examine the dispersion of the lowest bound state. Having established the properties of the single layer, we turn our attention to multilayers. The interaction of several layers leads to a phenomenon known as Davydov splitting. Under this lens, we investigate how the number of layers affects the excitonic properties of hBN, with particular focus on the Davydov splitting of the lowest bound exciton, which is responsible for the main feature of the absorption spectra. We discuss the effects responsible for the splitting of excitons in multilayers, and construct a simple one-dimensional model to provide a qualitative understanding of their absorption spectra as a function of the number of layers. In particular, we show that, from trilayers onwards, we can distinguish inner excitons, which are localized in the inner layers, and surface excitons, which are localized on the outer layers. Remarkably, the lowest bound bright state is found to be a surface exciton. Finally, we briefly present a comparison of tight-binding calculations with ab initio calculations of the absorption spectrum of bulk hBN. We discuss its first peaks, and how they are related to the excitons of single-layer hBN. [less ▲]

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