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See detail𝑘-Pareto Optimality for Many-Objective Genetic Optimization
Ruppert, Jean; Aleksandrova, Marharyta UL; Engel, Thomas UL

Poster (2021, July)

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See detailMoral Principles: Hedged, Contributory, Mixed
Knoks, Aleks UL

in Knoks, Aleks (Ed.) Deontic Logic and Normative Systems, 15th International Conference, DEON 2020/2021 (2021, July)

It's natural to think that the principles expressed by the statements "Promises ought to be kept" and "We ought to help those in need" are defeasible. But how are we to make sense of this defeasibility ... [more ▼]

It's natural to think that the principles expressed by the statements "Promises ought to be kept" and "We ought to help those in need" are defeasible. But how are we to make sense of this defeasibility? On one proposal, moral principles have hedges or built-in unless clauses specifying the conditions under which the principle doesn't apply. On another, such principles are contributory and, thus, do not specify which actions ought to be carried out, but only what counts in favor or against them. Drawing on a defeasible logic framework, this paper sets up three models: one model for each proposal, as well as a third model capturing a mixed view on principles that combines them. It then explores the structural connections between the three models and establishes some equivalence results, suggesting that the seemingly different views captured by the models are closer than standardly thought. [less ▲]

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See detailUnlinkable Updatable Hiding Databases and Privacy-Preserving Loyalty Programs
Damodaran, Aditya Shyam Shankar UL; Rial, Alfredo UL

in Proceedings on Privacy Enhancing Technologies (2021, July), 2021(3), 95-121

Loyalty programs allow vendors to profile buyers based on their purchase histories, which can reveal privacy sensitive information. Existing privacy friendly loyalty programs force buyers to choose ... [more ▼]

Loyalty programs allow vendors to profile buyers based on their purchase histories, which can reveal privacy sensitive information. Existing privacy friendly loyalty programs force buyers to choose whether their purchases are linkable. Moreover, vendors receive more purchase data than required for the sake of profiling. We propose a privacy-preserving loyalty program where purchases are always unlinkable, yet a vendor can profile a buyer based on her purchase history, which remains hidden from the vendor. Our protocol is based on a new building block, an unlinkable updatable hiding database (HD), which we define and construct. HD allows the vendor to initialize and update databases stored by buyers that contain their purchase histories and their accumulated loyalty points. Updates are unlinkable and, at each update, the database is hidden from the vendor. Buyers can neither modify the database nor use old versions of it. Our construction for HD is practical for large databases. [less ▲]

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See detailOn the Impact of Sample Duplication in Machine Learning based Android Malware Detection
Zhao, Yanjie; Li, Li; Wang, Haoyu et al

in ACM Transactions on Software Engineering and Methodology (2021), 30(3), 1-38

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See detailGeneralized Chern numbers based on open system Green's functions
Farias, Maria Belen UL; Groenendijk, Solofo; Schmidt, Thomas UL

in New Journal of Physics (2021), 23

We present an alternative approach to studying topology in open quantum systems, relying directly on Green's functions and avoiding the need to construct an effective non-Hermitian (nH) Hamiltonian. We ... [more ▼]

We present an alternative approach to studying topology in open quantum systems, relying directly on Green's functions and avoiding the need to construct an effective non-Hermitian (nH) Hamiltonian. We define an energy-dependent Chern number based on the eigenstates of the inverse Green's function matrix of the system which contains, within the self-energy, all the information about the influence of the environment, interactions, gain or losses. We explicitly calculate this topological invariant for a system consisting of a single 2D Dirac cone and find that it is half-integer quantized when certain assumptions about the self-energy are made. Away from these conditions, which cannot or are not usually considered within the formalism of nH Hamiltonians, we find that such a quantization is usually lost and the Chern number vanishes, and that in special cases, it can change to integer quantization. [less ▲]

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See detailSurface anchoring mediates bifurcation in nematic microflows within cylindrical capillaries
Paul, Steffen; Eric, Stellamanns; Sengupta, Anupam UL

in Physics of Fluids (2021), 33(072005), 072005-1-072005-13

Capillary microflows of liquid crystal phases are central to material, biological and bio-inspired systems. Despite their fundamental and applied significance, a detailed understanding of the stationary ... [more ▼]

Capillary microflows of liquid crystal phases are central to material, biological and bio-inspired systems. Despite their fundamental and applied significance, a detailed understanding of the stationary behavior of nematic liquid crystals (NLC-s) in cylindrical capillaries is still lacking. Here, using numerical simulations based on the continuum theory of Leslie, Ericksen, and Parodi, we investigate stationary NLC flows within cylindrical capillaries possessing homeotropic (normal) and uniform planar anchoring conditions. By considering the material parameters of the flow-aligning NLC, 5CB, we report that instead of the expected, unique director field monotonically approaching the alignment angle over corresponding Ericksen numbers (dimensionless number capturing viscous vs elastic effects), a second solution emerges at a threshold flow rate (or applied pressure gradient). We demonstrate that the onset of the second solution, a nematodynamic bifurcation yielding distinct director configurations at the threshold pressure gradient, can be controlled by the surface anchoring and the flow driving mechanism (pressure-driven or volume-driven). For homeotropic surface anchoring, this alternate director field orients against the alignment angle in the vicinity of the capillary center; while in the uniform planar case, the alternate director field extends throughout the capillary volume, leading to reduction of the flow speed with increasing pressure gradients. While the practical realization and utilization of such nematodynamic bifurcations still await systematic exploration, signatures of the emergent rheology have been reported by the authors previously within microfluidic environments, under both homeotropic and planar anchoring conditions. [less ▲]

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See detailThe sense of belonging in the context of migration and active ageing: The case of multicultural Luxembourg
Albert, Isabelle UL; Bemtgen, Nadia; Hoffmann, Martine et al

Scientific Conference (2021, July)

Migration is a life-changing transition and the establishment of new bonds in the receiving country constitutes an important developmental task. While feelings of belonging are closely linked to ... [more ▼]

Migration is a life-changing transition and the establishment of new bonds in the receiving country constitutes an important developmental task. While feelings of belonging are closely linked to subjective well-being, the feeling of not fitting in might be related to social exclusion and loneliness. Though social isolation is not bound to specific groups and ages, older migrants might be at a particular risk as recent studies suggest. The present study is part of the project PAN-VAL on active ageing in Luxembourg, financed by the Ministry of Family and Integration. Here, we focus on social embeddedness vs. social isolation of migrants and non-migrants living in the multicultural context of Luxembourg. Our aim is to identify facilitators and obstacles to participation in social activities, focusing in particular on the role of "sense of belonging" of older people to their place and country of residence. Applying a mixed-methods design, we will first focus on a national sample of N=1000 migrants and non-migrants 50+ living in Luxembourg who are asked about their family and friendship networks, leisure activities, sense of belonging to different entities (such as their neighborhood, municipality and country of residence) as well as their feelings of social isolation and loneliness. Secondly, we will draw on qualitative interviews in four selected municipalities contrasting active vs. non-active older migrants vs. non-migrants, exploring in more depth their experiences of belonging and social embeddedness. Results will be discussed in a life-span perspective, considering different developmental trajectories to belonging as a fundamental need of human beings. [less ▲]

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See detailSense of belonging, social embeddedness and perceived loneliness of older Luxembourgers and non-Luxembourgers in pandemic times
Albert, Isabelle UL; Bemtgen, Nadia; Hoffmann, Martine et al

Scientific Conference (2021, July)

Luxembourg has witnessed a sharp increase in cultural diversity due to high levels of immigration in the past years, and the question of how inhabitants from different cultural origin establish a sense of ... [more ▼]

Luxembourg has witnessed a sharp increase in cultural diversity due to high levels of immigration in the past years, and the question of how inhabitants from different cultural origin establish a sense of belonging to their country of residence has become essential for social cohesion and inclusion. The COVID-19 pandemic has, however, shaken patterns of belonging dramatically. The place of residence has gained new meaning due to confinement measures, closed borders and local contact restrictions. Physical distancing could have particularly adverse effects on older migrants with smaller social networks in the receiving country, increasing the risk for loneliness and social isolation. The present study is part of the PAN-VAL project on active ageing funded by the Luxembourgish Family Ministry. We aim to analyze the impact of sense of belonging and social embeddedness on perceived loneliness before and since the COVID-19 crisis of older Luxembourgers and non-Luxembourgers living in the Grand-Duchy. A representative sample of N=1000 residents 50+ participated in a survey via telephone and online in December 2020. The standardized questionnaire included questions regarding national and transnational family and friendship networks, contact frequencies, sense of belonging to place and country of residence and of origin as well as perceived loneliness before and since the COVID-19 pandemic. Preliminary findings indicate that sense of belonging predicted loneliness before and since the corona crisis, whereas a larger social network in Luxembourg was protective against loneliness only before but not since the crisis. Interestingly, a higher contact frequency with friends in Luxembourg reduced loneliness before the crisis, whereas higher contact frequency with friends abroad reduced loneliness since crisis. Results will be discussed considering resources as well as risk factors for loneliness in the context of migration and ageing in light of the current COVID-19 pandemic. [less ▲]

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See detailThe missing risk premium in exchange rates
Penasse, Julien UL; Magnus, Dahlquist

in Journal of Financial Economics (2021)

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See detailNB-IoT via LEO satellites: An efficient resource allocation strategy for uplink data transmission
Kodheli, Oltjon UL; Maturo, Nicola; Chatzinotas, Symeon UL et al

in IEEE Internet of Things Journal (2021)

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See detailRandom access procedure over non-terrestrial networks: From theory to practice
Kodheli, Oltjon UL; Abdalla, Abdelrahman UL; Querol, Jorge UL et al

in IEEE Access (2021)

Non-terrestrial Networks (NTNs) have become an appealing concept over the last few years and they are foreseen as a cornerstone for the next generations of mobile communication systems. Despite opening up ... [more ▼]

Non-terrestrial Networks (NTNs) have become an appealing concept over the last few years and they are foreseen as a cornerstone for the next generations of mobile communication systems. Despite opening up new market opportunities and use cases for the future, the novel impairments caused by the signal propagation over the NTN channel, compromises several procedures of the current cellular standards. One of the first and most important procedures impacted is the random access (RA) procedure, which is mainly utilized for achieving uplink synchronization among users in several standards, such as the fourth and fifth generation of mobile communication (4 & 5G) and narrowband internet of things (NB-IoT). In this work, we analyse the challenges imposed by the considerably increased delay in the communication link on the RA procedure and propose new solutions to overcome those challenges. A trade-off analysis of various solutions is provided taking into account also the already existing ones in the literature. In order to broaden the scope of applicability, we keep the analysis general targeting 4G, 5G and NB-IoT systems since the RA procedure is quasi-identical among these technologies. Last but not least, we go one step further and validate our techniques in an experimental setup, consisting of a user and a base station implemented in open air interface (OAI), and an NTN channel implemented in hardware that emulates the signal propagation delay. The laboratory test-bed built in this work, not only enables us to validate various solutions, but also plays a crucial role in identifying novel challenges not previously treated in the literature. Finally, an important key performance indicator (KPI) of the RA procedure over NTN is shown, which is the time that a single user requires to establish a connection with the base station. [less ▲]

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See detailInvestigating the influence of personalized musculoskeletal models on the calculated muscles and joints forces
Soliman, Ahmed Abdelsalam Mohamed UL; Kedziora, Slawomir UL; Kelm, Jens et al

Poster (2021, July)

It was the objective to analyze the influence of personalization of musculoskeletal models (MS) on muscle and contact joint forces for frequent daily movements. For normal gait cycle, we detect ... [more ▼]

It was the objective to analyze the influence of personalization of musculoskeletal models (MS) on muscle and contact joint forces for frequent daily movements. For normal gait cycle, we detect approximately 20% for some muscles attached to the pelvis, as well as for maximum hip-joint contact force. [less ▲]

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See detailDigitized-counterdiabatic quantum approximate optimization algorithm
Chandarana, P.; Hegade, N. N.; Paul, K. et al

in Physical Review Research (2021)

The quantum approximate optimization algorithm (QAOA) has proved to be an e ective classical-quantum algorithm serving multiple purposes, from solving combinatorial optimization problems to finding the ... [more ▼]

The quantum approximate optimization algorithm (QAOA) has proved to be an e ective classical-quantum algorithm serving multiple purposes, from solving combinatorial optimization problems to finding the ground state of many-body quantum systems. Since QAOA is an ansatz-dependent algorithm, there is always a need to design ansatz for better optimization. To this end, we propose a digitized version of QAOA enhanced via the use of shortcuts to adiabaticity. Specifically, we use a counterdiabatic (CD) driving term to design a better ansatz, along with the Hamiltonian and mixing terms, enhancing the global performance. We apply our digitizedcounterdiabatic QAOA to Ising models, classical optimization problems, and the P-spin model, demonstrating that it outperforms standard QAOA in all cases we study. [less ▲]

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See detailNew Field, Old Practices: Promises and Challenges of Public History
Cauvin, Thomas UL

in magazén | International Journal for Digital and Public Humanities (2021), 2(1), 13-44

lthough public history is becoming increasingly international, the field remains difficult to define and subject to some criticism. Based on sometimes long-established public practices, public history ... [more ▼]

lthough public history is becoming increasingly international, the field remains difficult to define and subject to some criticism. Based on sometimes long-established public practices, public history displays new approaches to audiences, collaboration and authority in history production. This article provides an overview of public history, its various definitions and historiography, and discusses some of the main criticisms of the field. Public history is compared to a tree of knowledge whose parts (roots, trunk, branches and leaves) represent the many collaborative and interconnected stages in the field. Defining public history as a systemic process (tree) demonstrates the need for collaboration between the different actors – may they be trained historians or not – and aim to focus on the role they play in the overall process. The future of international public history will involve balancing practice-based approaches with more theoretical discussions on the role of trained historians, audiences and different uses of the past. [less ▲]

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See detailInteractions between large molecules pose a puzzle for reference quantum mechanical methods
Yasmine S. Al-Hamdani; Péter R. Nagy; Andrea Zen et al

in Nature Communications (2021)

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See detailDiscovering Pesticides, Pharmaceuticals TPs in Luxembourg Waters using Open Cheminformatics Approaches
Krier, Jessy; Singh, Randolph R.; Kondic, Todor UL et al

Scientific Conference (2021, June 24)

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See detailChallenging the Status Quo: Citizens’ Access to Justice to Protect a Healthy Environment in Europe
Muñoz, Susana UL

Scientific Conference (2021, June 22)

The EU and its Member States must guarantee the respect of citizens’ right of access to environmental information, public participation in decision-making and access to justice in environmental matters ... [more ▼]

The EU and its Member States must guarantee the respect of citizens’ right of access to environmental information, public participation in decision-making and access to justice in environmental matters. Nevertheless, no framework for access to justice in the EU Member States exists. On 14 October 2020, the European Commission adopted a legislative proposal amending the Aarhus Regulation as part of the European Green Deal. The aim is to strengthen the EU’s system of access to justice in environmental matters, including the role of the Member States and national courts. Drawing on European and national case law and legislation, this paper provides a critical review of the current application of access to justice and the proposed amendments. It further explores legal avenues for strengthening the citizens’ access to justice within the multilevel protection of a healthy environment in Europe. [less ▲]

Detailed reference viewed: 46 (0 UL)