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See detailAutomotive Squint-forward-looking SAR: High Resolution and Early Warning
Hu, Ruizhi UL; Mysore Rama Rao, Bhavani Shankar UL; Murtada, Ahmed Abdelnaser Elsayed UL et al

in IEEE Journal of Selected Topics in Signal Processing (2021)

Forward-looking automotive radars can sense long-distant targets to enable early warning, but the lateral resolution is limited. Synthetic aperture radar (SAR) techniques can achieve very high azimuth ... [more ▼]

Forward-looking automotive radars can sense long-distant targets to enable early warning, but the lateral resolution is limited. Synthetic aperture radar (SAR) techniques can achieve very high azimuth resolution but cannot resolve targets in the forward direction. As a trade-off, squint-forward-looking SAR (SFL-SAR) can perform 2D imaging on a distant area squint to the moving direction, providing both high resolution and early warning. In this paper, we analyzed and derived the constraints of automotive SFL-SAR to satisfy both the required resolution and braking distance. Simulations and imaging results verified the analysis. [less ▲]

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See detailDigital history and the politics of digitization
Zaagsma, Gerben UL

Scientific Conference (2021, March 10)

This paper addresses the question of the politics of (cultural heritage) digitisation and its consequences for historical research. To put it simply, it discusses the question of why, where and how we can ... [more ▼]

This paper addresses the question of the politics of (cultural heritage) digitisation and its consequences for historical research. To put it simply, it discusses the question of why, where and how we can access what we can access. The online documentary record affects historical research and we need to understand how and in what ways our online evidentiary basis is constituted and might affect our research. [less ▲]

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See detailEnd-to-end Precoding Validation over a Live GEO Satellite Forward Link
Krivochiza, Jevgenij UL; Merlano Duncan, Juan Carlos UL; Querol, Jorge UL et al

in IEEE Access (2021)

In this paper we demonstrate end-to-end precoded multi-user multiple-input singleoutput (MU-MISO) communications over a live GEO satellite link. Precoded communications enable full frequency reuse (FFR ... [more ▼]

In this paper we demonstrate end-to-end precoded multi-user multiple-input singleoutput (MU-MISO) communications over a live GEO satellite link. Precoded communications enable full frequency reuse (FFR) schemes in satellite communications (SATCOM) to achieve broader service availability and higher spectrum efficiency than with the conventional four-color (4CR) and twocolor (2CR) reuse approaches. In this scope, we develop an over-the-air test-bed for end-to-end precoding validations.We use an actual multi-beam satellite to transmit and receive precoded signals using the DVB-S2X standard based gateway and user terminals. The developed system is capable of end-to-end real-time communications over the satellite link including channel measurements and precompensation. It is shown, that by successfully canceling inter-user interference in the actual satellite FFR link precoding brings gains in terms of enhanced SINR and increased system goodput. [less ▲]

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See detailOpenMP optimisation of the eXtended Discrete Element Method (XDEM)
Ojeda-May, Pedro; Eriksson, Jerry; Rousset, Alban UL et al

Report (2021)

The eXtended Discrete Element Method (XDEM) is an extension of the regular Discrete Element Method (DEM) which is a software for simulating the dynamics of granular material. XDEM extends the regular DEM ... [more ▼]

The eXtended Discrete Element Method (XDEM) is an extension of the regular Discrete Element Method (DEM) which is a software for simulating the dynamics of granular material. XDEM extends the regular DEM method by adding features where both micro and macroscopic observables can be computed simultaneously by coupling different time and length scales. In this sense XDEM belongs the category of multi-scale/multi-physics applications which can be used in realistic simulations. In this whitepaper, we detail the different optimisations done during the preparatory PRACE project to overcome known bottlenecks in the OpenMP implementation of XDEM. We analysed the Conversion, Dynamic, and the combined Dynamics-Conversion modules with Extrae/Paraver and Intel VTune profiling tools in order to find the most expensive functions. The proposed code modifications improved the performance of XDEM by ~17% for the computational expensive Dynamics-Conversion combined modules (with 48 cores, full node). Our analysis was performed in the Marenostrum 4 (MN4) PRACE infrastructure at Barcelona Supercomputing Center (BSC). [less ▲]

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See detailExploring the History of Digital History
Zaagsma, Gerben UL

Scientific Conference (2021, March 01)

This short paper will present the first results, and outline my new project which investigates the early trajectories of history and computing and focuses on the networks of computing historians in the ... [more ▼]

This short paper will present the first results, and outline my new project which investigates the early trajectories of history and computing and focuses on the networks of computing historians in the pre-PC and early PC period. [less ▲]

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See detailLa réforme du droit belge des sociétés, un exemple à suivre pour le Luxembourg ?
Corbisier, Isabelle UL; Prüm, André UL

Book published by Larcier (2021)

Le nouveau Code des sociétés et des associations, introduit par le législateur belge en 2019 et applicable aux sociétés existantes depuis le 1er janvier 2020, est-il un exemple qui ferait sens au ... [more ▼]

Le nouveau Code des sociétés et des associations, introduit par le législateur belge en 2019 et applicable aux sociétés existantes depuis le 1er janvier 2020, est-il un exemple qui ferait sens au Luxembourg ? De par ses évolutions marquantes, ce nouveau code a rendu le droit belge des sociétés davantage fonctionnel, flexible et attractif. L’ouvrage rend compte des grands changements intervenus et les met en perspective avec le droit luxembourgeois. Y sont notamment abordées les questions relatives à la notion d’« entreprise » et ses conséquences, à l’abandon du siège réel comme critère de rattachement, au nouveau statut de la société à responsabilité limitée, aux nouvelles règles de gouvernance et à la libéralisation du régime des titres. L’ouvrage rassemble les contributions de : Alexia Autenne, Roman Aydogdu, Isabelle Corbisier, Henri Culot, Pierre-Alexandre Degehet, Michel de Wolf, Katia Gauzès, Philippe Hoss,Yann Paclot, Yann Payen, Denis Philippe, André Prüm, Pit Reckinger, Pierre Schleimer, Laurent Schummer, Jean-Paul Spang et Nicolas [less ▲]

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See detailStadtentwicklung im vormodernen Europa. Beobachtungen zu Kontinuitäten und Brüchen
Pauly, Michel UL; Stercken, Martina

Book published by Chronos - 2nd revised edition (2021)

Beobachtungen zu Permanenzen und Wandel stehen im Zentrum der Skizze zur Stadtentwicklung in Westeuropa. Sie unternimmt den Versuch, langlebige Verhältnisse und deutliche Einschnitte in einer weiten ... [more ▼]

Beobachtungen zu Permanenzen und Wandel stehen im Zentrum der Skizze zur Stadtentwicklung in Westeuropa. Sie unternimmt den Versuch, langlebige Verhältnisse und deutliche Einschnitte in einer weiten zeitlichen und räumlichen Perspektive zu umreissen, die von der Verfestigung der neuen städtischen Lebensform im 12. Jahrhundert bis ins 19. Jahrhundert reicht, als sich mit der politischen Neuordnung und der Industrialisierung die Vorstellungen von Stadt veränderten. Zusammengeführt und partiell neu bewertet werden damit epochenspezifische Befunde der historischen Forschung zur mittelalterlichen und frühneuzeitlichen Stadt, vergleichende Untersuchungen zu regionalen Unterschieden in Westeuropa und Erkenntnisse anderer an der Städteforschung beteiligter Disziplinen. [less ▲]

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See detailContribution à la réactualisation théorique du rapport entre le contrat et la relation contractuelle au 21e siècle à partir des travaux de Axel Honneth sur la reconnaissance
Dufour, Pascale UL

Doctoral thesis (2021)

The aim of this interdisciplinary thesis is to engage a new theoretical reflection on the function of the contract. It essentially seeks to explain the link between objective law as applied to contractual ... [more ▼]

The aim of this interdisciplinary thesis is to engage a new theoretical reflection on the function of the contract. It essentially seeks to explain the link between objective law as applied to contractual relationships and intersubjective recognition. Honneth’s theoretical framework of recognition is used in order to rethink the classic conceptual toolbox of contractual legal theory, specifically the autonomy of the will and contractual liberty. By reevaluating contractual relationships through the prism of recognition and intersubjectivity, it appears that positive law neither voids nor contradicts these principles. Indeed, a fair number of provisions exist in a different legal realm, guaranteeing the minimal individual independence and social liberty of legal parties in their concrete contractual relationship. The contract, governing individual relationships between parties through positive law, takes on an institutional function beyond its symbolic function, at the crossroads of economic, political and social considerations. The limits of the contract’s function are revealed by the critique of the common legal techniques as well as the level of institutionalization of the contractual relationship. This argumentative decentering stays in line with liberal thinking whilst simultaneously rejecting the postulate of legal individualism, which still is the main critique regarding the principle of the autonomy of the will. This thesis is part of the civil law tradition and mainly draws on examples from Quebec Law and French Law. The conclusions pertaining to the function of the contract enable various explanations of certain contractual phenomena (contracts of adhesion, consumer contracts, default, pre-contractual obligations, etc.) and question many fundamental theoretical discourses in contractual theory (capacity, contractual justice, binding force of the contract, unforeseen events, etc.). [less ▲]

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See detailUnd was ist mit den Kindern? COVID-Kids: Daten aus der Schweitz
Kirsch, Claudine UL

Scientific Conference (2021, January 18)

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See detailExtended telecommuting due to COVID-19 and the impact on working life
Sischka, Philipp UL; Steffgen, Georges UL

in Mein, Georg; Pause, Johannes (Eds.) Self and Society in the Corona Crisis. Perspectives from the Humanities and Social Sciences (2021)

The corona virus (COVID-19) pandemic has changed the working lives of people all over the world, amongst others, the labor market has seen a sharp increase in telecommuting. Therefore, the extent of ... [more ▼]

The corona virus (COVID-19) pandemic has changed the working lives of people all over the world, amongst others, the labor market has seen a sharp increase in telecommuting. Therefore, the extent of telecommuting in Luxembourg as well as definitions and different arrangements of telecommuting will be presented. Thereafter the chapter looks at merits and demerits of telecommuting and the boundary conditions of successfully working from home by focusing on the extraordinary situation under which telework currently takes place. In this regard, the effects of telecommuting on the individual, the organization and the society are outlined and discussed. Finally, the chapter closes highlighting requirements for effective telecommuting and describing ongoing research about the effects of telecommuting on different working conditions in Luxembourg. [less ▲]

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See detailQuality of life among adult patients living with diabetes in Rwanda: a cross-sectional study in outpatient clinics
Lygidakis, Charilaos; Uwizihiwe, Jean Paul; Bia, Michela Gianna UL et al

in BMJ Open (2021), 11

Objectives To report on the disease-related quality of life of patients living with diabetes mellitus in Rwanda and identify its predictors. Design Cross-sectional study, part of the baseline assessment ... [more ▼]

Objectives To report on the disease-related quality of life of patients living with diabetes mellitus in Rwanda and identify its predictors. Design Cross-sectional study, part of the baseline assessment of a cluster-randomised controlled trial. Setting Outpatient clinics for non-communicable diseases of nine hospitals across Rwanda. Participants Between January and August 2019, 206 patients were recruited as part of the clinical trial. Eligible participants were those aged 21–80 years and with a diagnosis of diabetes mellitus for at least 6 months. Illiterate patients, those with severe hearing or visual impairments, those with severe mental health conditions, terminally ill, and those pregnant or in the postpartum period were excluded Primary and secondary outcome measures Disease-specific quality of life was measured with the Kinyarwanda version of the Diabetes-39 (D-39) questionnaire. A glycated haemoglobin (HbA1c) test was performed on all patients. Sociodemographic and clinical data were collected, including medical history, disease-related complications and comorbidities. Results The worst affected dimensions of the D-39 were ‘anxiety and worry’ (mean=51.63, SD=25.51), ‘sexual functioning’ (mean=44.58, SD=37.02), and ‘energy and mobility’ (mean=42.71, SD=20.69). Duration of the disease and HbA1c values were not correlated with any of the D-39 dimensions. A moderating effect was identified between use of insulin and achieving a target HbA1c of 7% in the ‘diabetes control’ scale. The most frequent comorbidity was hypertension (49.0% of participants), which had a greater negative effect on the ‘diabetes control’ and ‘social burden’ scales in women. Higher education was a predictor of less impact on the ‘social burden’ and ‘energy and mobility’ scales. Conclusions Several variables were identified as predictors for the five dimensions of quality of life that were studied, providing opportunities for tailored preventive programmes. Further prospective studies are needed to determine causal relationships. [less ▲]

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See detailMuDelta: Delta-Oriented Mutation Testing at Commit Time
Ma, Wei UL; Thierry Titcheu, Chekam; Papadakis, Mike UL et al

in International Conference on Software Engineering (ICSE) (2021)

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See detailGaussian fluctuation for Gaussian Wishart matrices of overall correlation
Nourdin, Ivan UL; Pu, Fei

E-print/Working paper (2021)

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See detailPost-Quantum Secure LFE for L/poly with Smaller Parameters
Naccache, David; Rosie, Razvan UL; Spignoli, Lorenzo UL

E-print/Working paper (2021)

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See detailAnimal Faces: the Question of the Gaze
Roelens, Nathalie UL

in Lexia (2021)

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See detailNormalization as a mediator of emotion during unemployment
Houssemand, Claude UL; Rosato, Valeria; Thill, Steve et al

in Anxiety, Stress and Coping (2021)

Meta-analyses indicated detrimental effects on some psychological dimensions from job loss and extended periods of unemployment. This study analyses three phenomena: causes attributed to unemployment ... [more ▼]

Meta-analyses indicated detrimental effects on some psychological dimensions from job loss and extended periods of unemployment. This study analyses three phenomena: causes attributed to unemployment; processes for coping with unemployment; and the emotional impact of joblessness. Using an SEM approach, a model is created in which unemployment normalization acts as a mediator between locus of control and emotions. Method: questionnaires from 260 unemployed people in Luxembourg provided data on perceived control, coping, and emotions. Participants who attribute their situation to bad luck, believe more strongly that unemployment is due to external factors beyond their control, and recognize unemployment as being a common occurrence in life. Such cognitive attribution of unemployment has effects on job seekers’ emotions. Those who perceive unemployment in a more positive light experience more positive emotions and fewer negative affects. Negative perceptions of unemployment have no effect on the generation of positive emotion, but have an influence on negative affects. Finally, the influence of perceived-control on emotion is not direct, but is mediated by processes of unemployment normalization. Understanding how unemployed people perceive and experience their situations could help them be more effective in their search for new employment [less ▲]

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See detailInverse deformation analysis: an experimental and numerical assessment using the FEniCS Project
Mazier, Arnaud UL; Bilger, Alexandre; Forte, Antonio E. et al

E-print/Working paper (2021)

In this paper, we develop a framework for solving inverse deformation problems using the FEniCS Project finite element software. We validate our approach with experimental imaging data acquired from a ... [more ▼]

In this paper, we develop a framework for solving inverse deformation problems using the FEniCS Project finite element software. We validate our approach with experimental imaging data acquired from a soft silicone beam under gravity. In contrast with inverse iterative algorithms that require multiple solutions of a standard elasticity problem, the proposed method can compute the undeformed configuration by solving only one modified elasticity problem. This modified problem has a complexity comparable to the standard one. The framework is implemented within an open-source pipeline enabling the direct and inverse deformation simulation directly from imaging data. We use the high-level Unified Form Language (UFL) of the FEniCS Project to express the finite element model in variational form and to automatically derive the consistent Jacobian. Consequently, the design of the pipeline is flexible: for example, it allows the modification of the constitutive models by changing a single line of code. We include a complete working example showing the inverse deformation of a beam deformed by gravity as supplementary material. [less ▲]

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See detailA fault detector/classifier for closed-ring power generators using machine learning
Quintanilha, Igor M.; Elias, Vitor R. M.; Silva, Felipe B. et al

in Reliability Engineering and System Safety (2021)

Condition-based monitoring of power-generation systems is naturally becoming a standard approach in industry due to its inherent capability of fast fault detection, thus improving system efficiency and ... [more ▼]

Condition-based monitoring of power-generation systems is naturally becoming a standard approach in industry due to its inherent capability of fast fault detection, thus improving system efficiency and reducing operational costs. Most such systems employ expertise-reliant rule-based methods. This work proposes a different framework, in which machine-learning algorithms are used for detecting and classifying several fault types in a power-generation system of dynamically positioned vessels. First, principal component analysis is used to extract relevant information from labeled data. A random-forest algorithm then learns hidden patterns from faulty behavior in order to infer fault detection from unlabeled data. Results on fault detection and classification for the proposed approach show significant improvement on accuracy and speed when compared to results from rule-based methods over a comprehensive database. [less ▲]

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See detailKernel Regression on Graphs in Random Fourier Features Space
Elias, Vitor R. M.; Gogenini, Vinay C.; Alves Martins, Wallace UL et al

in IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP-2021), Toronto 6-11 June 2021 (2021)

This work proposes an efficient batch-based implementation for kernel regression on graphs (KRG) using random Fourier features (RFF) and a low-complexity online implementation. Kernel regression has ... [more ▼]

This work proposes an efficient batch-based implementation for kernel regression on graphs (KRG) using random Fourier features (RFF) and a low-complexity online implementation. Kernel regression has proven to be an efficient learning tool in the graph signal processing framework. However, it suffers from poor scalability inherent to kernel methods. We employ RFF to overcome this issue and derive a batch-based KRG whose model size is independent of the training sample size. We then combine it with a stochastic gradient-descent approach to propose an online algorithm for KRG, namely the stochastic-gradient KRG (SGKRG). We also derive sufficient conditions for convergence in the mean sense of the online algorithms. We validate the performance of the proposed algorithms through numerical experiments using both synthesized and real data. Results show that the proposed batch-based implementation can match the performance of conventional KRG while having reduced complexity. Moreover, the online implementations effectively learn the target model and achieve competitive performance compared to the batch implementations. [less ▲]

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See detailADS-B Signal Detection via Time-Frequency Analysis for Radio Astronomy Applications
Silva, Felipe B.; Cetin, Ediz; Alves Martins, Wallace UL

in IEEE International Symposium on Circuits and Systems (ISCAS), Daegu 22-28 May 2021 (2021)

This paper proposes a time-frequency (TF) domain technique for detecting the presence of automatic dependent surveillance-broadcast (ADS-B) interference signals in radio astronomy applications. The ... [more ▼]

This paper proposes a time-frequency (TF) domain technique for detecting the presence of automatic dependent surveillance-broadcast (ADS-B) interference signals in radio astronomy applications. The proposed technique uses a priori knowledge about the ADS-B signal’s frequency information and compares it with the received signal’s spectrogram time slices via the cosine similarity function. In the presence of ADS-B signals, the similarity levels are higher, whereas in their absence the levels are lower. Hence, the proposed approach exploits this to detect the presence of such signals. Simulation results using signals from the Parkes radio telescope show the efficacy of the proposed method in detecting the presence of ADS-B signals when compared with other classic detectors. [less ▲]

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