Is There a Need for a Directive on Pillar Two? A Few Normative Comments.

in Intertax, International Tax Review (2022), 50(6/7), 527-530

Poland’s request to link the entry into force of the Pillar 2 Directive to an international agreement on Pillar 1 raises fundamental questions about the European constitutional structure. Beyond the mere ... [more ▼]

Poland’s request to link the entry into force of the Pillar 2 Directive to an international agreement on Pillar 1 raises fundamental questions about the European constitutional structure. Beyond the mere legality of such a link, this contribution seeks to respond to some normative concerns related to the creation of such secondary legislation. [less ▲]

Opinion Statement ECJ-TF 2/2022 on the Decision of 27 January 2022 in European Commission v. Kingdom of Spain (Form 720) (Case C-788/19)

in European Taxation (2022), 62(7), 304-310

In this CFE Opinion Statement, the CFE ECJ Task Force comments on the decision of 27 January 2022 in European Commission v. Kingdom of Spain (Form 720) (Case C-788/19) on the lack of proportionality of ... [more ▼]

In this CFE Opinion Statement, the CFE ECJ Task Force comments on the decision of 27 January 2022 in European Commission v. Kingdom of Spain (Form 720) (Case C-788/19) on the lack of proportionality of the consequences derived from the failure to provide information concerning assets or rights held in other Member States of the European Union or the European Economic Area. [less ▲]

Le corpus hagiographique de Trèves au début du XVIe siècle. Enquête stylométrique et premiers résultats

in Bulletin du Centre d'Études Médiévales d'Auxerre (2022)

Préserve-moi ! Des journaux intimes à ceux de confinement dans les archives du Web

in Le Temps des Médias (2022)

Souvent éphémères, les pages personnelles, les blogs et aujourd’hui les écritures de soi et intimes sur les réseaux socio-numériques, jusqu’aux journaux de confinement nés lors de la crise COVID, sont ... [more ▼]

Souvent éphémères, les pages personnelles, les blogs et aujourd’hui les écritures de soi et intimes sur les réseaux socio-numériques, jusqu’aux journaux de confinement nés lors de la crise COVID, sont toutefois partiellement préservés dans les archives du Web. En explorant leur conservation, notamment au sein de la Bibliothèque nationale de France, et les limites et défis que posent ces sources nativement numériques, il s’agit de saisir les enjeux de préservation de ces contenus personnels, intimes, littéraires, vernaculaires, multimédias, mais aussi les possibilités de recherche qu’ils offrent pour l’histoire du numérique et de ses cultures. [less ▲]

Outage Performance of Satellite Terrestrial Full-DuplexRelaying Networks with Co-Channel Interference

in IEEE Wireless Communications Letters (2022), 11(7), 1478-1482

This letter investigates the performance of thesatellite-terrestrial networks (STN), where a satellite tries totransmit information to a ground user through the help of mul-tiple decode-and-forward relays ... [more ▼]

This letter investigates the performance of thesatellite-terrestrial networks (STN), where a satellite tries totransmit information to a ground user through the help of mul-tiple decode-and-forward relays and the existence of co-channelinterference sources. In particular, the full-duplex technique andpartial relay selection are applied at the relay to increase the totalthroughput at the destination, enhance the system reliability, andreduce the complexity. In this context, the outage probability (OP)is computed in a closed-form expression. Numerical results areprovided to confirm the accuracy of the proposed mathematicalframework. Our findings illustrate that the outage performancecan be effectively enhanced by increasing either number of relaysor transmit power. [less ▲]

Comment on “Dispersion Interaction between Two Hydrogen Atoms in a Static Electric Field”

in Physical Review Letters (2022)

Recent Developments and Overview of the Country and Practitioner’s Reports

in European Data Protection Law Review (2022), 8(2), 250-254

Digital Twin for Human–Robot Interactions by Means of Industry 4.0 Enabling Technologies

in Sensors (2022), 22(13), 1-17

BIGDML—Towards accurate quantum machine learning force fields for materials

in Nature Communications (2022)

1 Energy-Efficient Hybrid Beamforming for Multi-Layer RIS-Assisted Secure Integrated Terrestrial-Aerial Network

in IEEE Transactions on Communications (2022), 70(6), 4189-4210

The integration of aerial platforms to provide ubiq- uitous coverage and connectivity for densely deployed terrestrial networks is expected to be a reality in emerging sixth-generation networks. Energy ... [more ▼]

The integration of aerial platforms to provide ubiq- uitous coverage and connectivity for densely deployed terrestrial networks is expected to be a reality in emerging sixth-generation networks. Energy-effificient design and secure transmission are two crucial issues for integrated terrestrial-aerial networks. With this focus, due to the potential of RIS in substantially saving power consumption and boosting the security of private information by enabling a smart radio environment, this paper investigates the energy-efficient hybrid beamforming for multi- layer reconfigurable intelligent surface (RIS)-assisted secure in- tegrated terrestrial-aerial network for defending against simul- taneous jamming and eavesdropping attacks. Specifically, with the available of angular information based imperfect channel state information (CSI), we propose a framework for the joint optimization of user’s received precoder, terrestrial BS’s and HAP’s digital precoder, and multi-layer RIS analog precoder to maximize the system energy efficiency (EE) performance. For the design of received precoder, a heuristic beamforming scheme is proposed to convert the worst-case problem into a min-max one such that a closed-form solution is derived. For the design of digital precoder, we propose an iterative sequential convex approximation approach via capitalizing the auxiliary variables and first-order Taylor series expansion. Finally, a monotonic vertex-update algorithm with penalty convex concave procedure is proposed to obtain analog precoder with low computational complexity. Numerical results show the superiority and effective- ness of proposed optimization framework and architecture [less ▲]

Characterization of unconventional sand-based substrates for adsorption of micropollutants in nature-based systems

in Journal of Environmental Management (2022)

The focus of this study is the characterization of unconventional sand-based substrates used in our previous project EmiSûre, (Interreg Greater Region (German federal states Rhineland-Palatinate and ... [more ▼]

The focus of this study is the characterization of unconventional sand-based substrates used in our previous project EmiSûre, (Interreg Greater Region (German federal states Rhineland-Palatinate and Saarland, the Grand Duchy of Luxembourg, regions Wallonia and Lorraine from Belgium and France, respectively), 2017–2021). The project aimed to develop and test alternative, nature-based technologies for the elimination of micropollutants (MPs) from municipal wastewater. For the characterization, two approaches were chosen. In the first approach, adsorption kinetics with a single compound allowed a perception of the adsorption capacity of the studied substrates compared to conventional substrates (granular activated carbons). This knowledge was completed by the second approach: an implementation of the studied substrates in packed-bed columns, which treated a mixture of 27 MPs in tap water for 10 months. Additionally, all three substrates (bentonite sand, sand with 15% activated biochar and sand with 15% zeolite) were characterized for physical and chemical properties, and the microbial potential of the activated and non-activated biochar was examined. From the studies, it is clear that the sand with an admixture of activated biochar is the most efficient sorbent in terms of single compound adsorption in batch (dye) and adsorption of 27 MPs on packed-bed columns. In contrast to the two other substrates, it shows long-term stable removal efficiencies. In the packed-bed columns, 18 out of 27 compounds were removed on average with high efficiency (80–99%), which is impressive, if we consider the variety of the compounds examined (pharmaceuticals, herbicides, pesticides, etc.) and their removal in conventional treatments. Addi- tionally, adsorption models were created for the experimental data of all compounds adsorbed on the substrate with an admixture of activated biochar resulting in the best fit with the combined Langmuir-Freundlich model. These satisfying results suggest the application of the sand-based substrate with an admixture of activated biochar for further research and possibly upscale installations with the aim to offer and prove a reasonable and efficient alternative for MPs elimination from municipal wastewater. [less ▲]

Evaluating Technology-Enhanced, STEAM-Based Remote Teaching With Parental Support in Luxembourgish Early Childhood Education

in Frontiers in Education (2022), 7(872479), 1-12

During COVID-19 confinement, we observed numerous challenges in using educational technology in early childhood Science–Technology–Engineering–Arts–Mathematics (STEAM) education in Luxembourg. Thus, we ... [more ▼]

During COVID-19 confinement, we observed numerous challenges in using educational technology in early childhood Science–Technology–Engineering–Arts–Mathematics (STEAM) education in Luxembourg. Thus, we designed a conceptual framework on parent-assisted remote teaching with active uses of educational technology supported by cycles of design-based research. After a previous study utilizing computer-aided design (CAD) software and three-dimensional (3D) printing in primary education, we used our initial findings to work with 12 early childhood students (ages 4–6), together with their teachers and parents in the second remote teaching period in Luxembourg. We created a STEAM modeling task with CAD software on robots and collected data through chat responses, messageboards, and online communication channels during a 3-week period. Here, we observed new roles in the parent–child relationship while learning STEAM in remote teaching with technology, and new opportunities in using educational technology overall in early childhood education. In this article, we have described findings that are likely to influence students’ learning and parent-assisted teaching, in particular parents and students’ perceptions and motivations, together with the way in which parents provide technical knowledge and support in remote early childhood STEAM education. [less ▲]

Teachers misunderstanding of translanguaging in preschools

in OASIS (2022)

Young multilingual children translanguage naturally. They use their linguistic and non-linguistic repertoire to express themselves, but also to make meaning of school environment and learn. When ... [more ▼]

Young multilingual children translanguage naturally. They use their linguistic and non-linguistic repertoire to express themselves, but also to make meaning of school environment and learn. When multilingual children come to a school where they do not understand the language of instruction, they are confronted with learning difficulties, which influences both their school progress and well-being. Translanguaging pedagogy helps teachers to create a space in which multilingual children can make meaning, feel well, and learn. By using this pedagogy, teachers support children’s multilingualism, which they see as a resource, and design inclusive activities accordingly. In this study, 40 Luxembourgian preschool teachers followed a professional development course in translanguaging pedagogy over six months. After the course, the researchers filmed teachers’ translanguaging activities with children. Three foci teachers designed an activity in which they invited three Portuguese and one Serbian child to choose the flag of their countries. However, all four children said that they speak Luxembourgish and thus wanted to choose the Luxembourgish flag. The teachers insisted that the children should choose Portuguese and Serbian flags, explaining that it is not possible for them to speak Luxembourgish. The children were confused and their body language showed their silencing, diminishing and shutting down. This scene showed not only that teachers misunderstood translanguaging, which they saw as multiple languages attached with nation states and flags, but they also, despite their good intentions, showed raciolinguistic ideologies, harmful for children in question. [less ▲]

We need a broader debate on the sustainability of blockchain

in Joule (2022), 6(6), 1137-1141

Context Stability in Habit Building Increases Automaticity and Goal Attainment

in Frontiers in Psychology (2022)

In this paper, we investigate the effects of context stability on automaticity and goal attainment in intentional habit building. We used hierarchical growth curve modeling and multilevel mediation to ... [more ▼]

In this paper, we investigate the effects of context stability on automaticity and goal attainment in intentional habit building. We used hierarchical growth curve modeling and multilevel mediation to test our hypotheses on two datasets. In Study 1, N = 95 university students (N = 2,482 habit repetitions) built new study habits over a period of 6 weeks with manipulated context stability. One group was instructed to constantly vary the context of their habit repetitions by changing rooms and times and the other group was instructed to keep the context of habit performance stable. In Study 2, N = 308 habits (N = 2,368 habit repetitions) from N = 218 users of a published habit building app were analyzed without manipulating but measuring context stability. We found the same pattern in both datasets: Context stability predicted more automaticity and higher habit repetition goal attainment. We also found that the effect of context stability on habit repetition goal attainment was partially mediated by automaticity in both datasets. These results show that context does not only act as a trigger for habit instigation but also has an ongoing effect on habit execution. [less ▲]

The dynamics of achievement inequalities: the role of performance and choice in Chile

in International Journal of Educational Development (2022), 92(C),

Research on education inequalities has long established the relationship between the social composition of schools and achievement levels. However, the empirical study of the social processes in choosing ... [more ▼]

Research on education inequalities has long established the relationship between the social composition of schools and achievement levels. However, the empirical study of the social processes in choosing schools and their potential effects on achievement inequalities has often been neglected. This article investigates the extent to which such social processes, related to parents’ educational preferences and expectations, influence the development of students’ achievement throughout their schooling career, as a channel of transmission of social inequality. Using longitudinal census data from Chile, which allows us to observe students’ achievements between the 4th and 10th grades, we find support for the claim that the development of achievement inequalities operate partly through well-off parents’ educational preferences and expectations. Moreover, these preferences and beliefs explain most of the social composition effect of schools on achievement inequalities. We conclude that choice processes should be considered as an integral part of theories aimed to explain achievement inequalities as a dynamic process. [less ▲]

Tussen New York en Genève: VN-Kroniek

in Nederlands Tijdschrift voor de Mensenrechten (2022), 47(2),

Deze kroniek informeert over ontwikkelingen met betrekking tot de mensenrechten in de diverse organen van de Verenigde Naties. Daarbij komen zowel de politieke mechanismen (onder meer de Algemene ... [more ▼]

Deze kroniek informeert over ontwikkelingen met betrekking tot de mensenrechten in de diverse organen van de Verenigde Naties. Daarbij komen zowel de politieke mechanismen (onder meer de Algemene Vergadering en de Mensenrechtenraad) aan de orde, als de diverse verdragscomités. [less ▲]

Outage and capacity analysis of NOMA systems over dual-hop mixed powerline-wireless channels

in ICT Express (2022)

Non-orthogonal multiple access (NOMA) has emerged as a promising technology for 5G networks and beyond. In order to fully reap the benefits of NOMA, it is essential to characterize its performance under ... [more ▼]

Non-orthogonal multiple access (NOMA) has emerged as a promising technology for 5G networks and beyond. In order to fully reap the benefits of NOMA, it is essential to characterize its performance under different channel fading. In this paper, we carry out a performance analysis of the downlink NOMA-based dual-hop mixed powerline/wireless communication (PLC/WLC) system. Specifically, we investigate the system reliability and spectrum efficiency in terms of the outage probability and the ergodic capacity, respectively, where the PLC link undergoes lognormal fading while the WLC link undergoes block Rayleigh fading. The accuracy of the analytical results has been validated, the effect of different system controlling parameters is tested; and the optimal values of power allocation factors are obtained. Also, the system performance is compared to a benchmark system through representative extensive simulations. [less ▲]

Uniaxial polarization analysis of bulk ferromagnets: theory and first experimental results

in Journal of Applied Crystallography (2022), 55

Based on Brown’s static equations of micromagnetics, the uniaxial polarization of the scattered neutron beam of a bulk magnetic material is computed. The approach considers a Hamiltonian that takes into ... [more ▼]

Based on Brown’s static equations of micromagnetics, the uniaxial polarization of the scattered neutron beam of a bulk magnetic material is computed. The approach considers a Hamiltonian that takes into account the isotropic exchange interaction, the antisymmetric Dzyaloshinskii–Moriya interaction, magnetic anisotropy, the dipole–dipole interaction, as well as the effect of an applied magnetic field. In the high-field limit, the solutions for the magnetization Fourier components are used to obtain closed-form results for the spinpolarized SANS (small-angle neutron scattering) cross sections and the ensuing polarization. The theoretical expressions are compared with experimental data on a soft magnetic nanocrystalline alloy. The micromagnetic SANS theory provides a general framework for polarized real-space neutron methods, and it may open up a new avenue for magnetic neutron data analysis on magnetic microstructures. [less ▲]

Strangeness in Early Stuart Drama

in Critical Survey (2022), 34(2), 1-106

Assessing the impact of micropollutants mitigation measures using vertical flow constructed wetlands for municipal wastewater catchments in the greater region: a reference case for rural areas

in Water Science and Technology (2022)

The present research aims at giving an approach to the issue of surface water contamination due to micropollutants in rural areas. The catchment of the Sûre river was selected as a reference case for the ... [more ▼]

The present research aims at giving an approach to the issue of surface water contamination due to micropollutants in rural areas. The catchment of the Sûre river was selected as a reference case for the Greater Region, characterized mainly by settlements with low population density, small water bodies and small- to medium-sized wastewater treatment plants (WWTPs). For these WWTPs, conventional technical solutions for micropollutants elimination are not suitable; therefore, an adapted mitigation strategy is needed to prevent the impact of micropollutants, especially during the dry season. As a suitable alternative to more intensive technologies, Constructed Wetlands (CW) in Vertical Flow (VF) configuration have been successfully tested over one-year period and the elimination rate of 27 micropollutants was quantified. Emission reduction by VF was then considered in a static mass balance model that calculates the longitudinal concentrations profile for the entire river catchment. The EmiSûre approach which focuses on river quality (concentrations of pollutants) instead of emitted loads, effectively allowed to simulate adopted measures a priori and resulted efficient to support decision-makers with WWTPs upgrade scenarios. [less ▲]

A Multidisciplinary Approach to Assess Smallholder Farmers’ Adoption of New Technologies in Development Interventions

in European Journal of Development Research (2022)

In spite of decades of research, the complexity of new technology uptake by smallholder farmers in the context of development interventions is still little understood. In order to unravel the motives for ... [more ▼]

In spite of decades of research, the complexity of new technology uptake by smallholder farmers in the context of development interventions is still little understood. In order to unravel the motives for, and barriers to, technology adoption, we propose a multidisciplinary qualitative framework that expands the Sustainable Livelihoods Framework with the agronomic Agrarian system approach and the Development anthropology-based ECRIS (Rapid Collective Inquiry for the Identification of Conflicts and Strategic Groups) approach. Such a framework allows to analyze smallholder farmers’ livelihoods, agricultural activities from an ecological cum technical cum economic point of view, and social learning processes involving power relationships. Its use is exemplified by studying the adoption of stone bunds in an agroecological development program in Burkina Faso. Many farmers cannot adopt this technology fully because of agricultural production system or livelihood shaped barriers, and because of power relationships bearing on the technology uptake process. [less ▲]

Unified, Labeled, and Semi-Structured Database of Pre-Processed Mexican Laws

in Data (2022), 7(91),

This paper presents a corpus of pre-processed Mexican laws for computational tasks. The main contributions are the proposed JSON structure and the methodology used to achieve the semi-structured corpus ... [more ▼]

This paper presents a corpus of pre-processed Mexican laws for computational tasks. The main contributions are the proposed JSON structure and the methodology used to achieve the semi-structured corpus with the selected algorithms. Law PDF documents were transformed into plain text, unified by a deconstruction of law–document structure, and labeled with natural language processing techniques considering part of speech (PoS); a process of entity extraction was also performed. The corpus includes the Mexican constitution and the Mexican laws that were collected from the official site in PDF format repealed before 14 October 2021. The collection has 305 documents, including: the Mexican constitution, 289 laws, 8 federal codes, 3 regulations, 2 statutes, 1 decree, and 1 ordinance. The semi-structured database includes the transformation of the set of laws from PDF format to a digital representation in order to facilitate its computational analysis. The documents were migrated to JSON type files to represent internal hierarchical relations. In addition, basic natural language processing techniques were implemented on laws for the identification of part of speech and named entities. The presented data set is mainly useful for text analysis and data science. It could be used for various legislative analysis tasks including: comprehension, interpretation, translation, classification, accessibility, coherence, and searches. Finally, we present some statistic of the identified entities and an example of the usefulness of the corpus for environmental laws. [less ▲]

Adaptive model to increase resilience for emerging supply chains within the circular economs - 'Zirkelmesser' an innovative case study

in Procedia CIRP (2022)

Variations in quantities, qualities and time availability of input materials pose a major risk to circular supply chains (CSC) and require new models for creating and evaluating adaptive and resilient CSC ... [more ▼]

Variations in quantities, qualities and time availability of input materials pose a major risk to circular supply chains (CSC) and require new models for creating and evaluating adaptive and resilient CSC in the circular economy (CE). This can be achieved by consistently modelling the overarching relationship between resource input- and output streams, without neglecting the associated risks. The model proposed below consists of five components which are based on five resilience requirements for SCs and provides a data-based recommended course of action for managers at a low entry-barrier. It consists of a CSC visualization, a safety stock calculation, a risk monitoring for each SC node, a reporting logic, and a measurement catalogue. The inspiration for this model came from an innovative case study (“Zirkelmesser”) in the metal processing industry in which secondary products and materials are used to produce new products. Here, the problem of maintaining the resource supply arose and led to resilience issues. The mentioned case study is used as an application example for the model application and helps to make emerging circular supply chains predictable and better manageable, thus increasing their resilience. [less ▲]

A Family of Hybrid Federated and CentralizedLearning Architectures in Machine Learning

in IEEE Transactions on Cognitive Communications and Networking (2022)

Many of the machine learning tasks focus on cen-tralized learning (CL), which requires the transmission of localdatasets from the clients to a parameter server (PS) entailing hugecommunication overhead ... [more ▼]

Many of the machine learning tasks focus on cen-tralized learning (CL), which requires the transmission of localdatasets from the clients to a parameter server (PS) entailing hugecommunication overhead. To overcome this, federated learning(FL) has been a promising tool, wherein the clients send only themodel updates to the PS instead of the whole dataset. However,FL demands powerful computational resources from the clients.Therefore, not all the clients can participate in training if they donot have enough computational resources. To address this issue,we introduce a more practical approach called hybrid federatedand centralized learning (HFCL), wherein only the clients withsufficient resources employ FL, while the remaining ones sendtheir datasets to the PS, which computes the model on behalf ofthem. Then, the model parameters corresponding to all clientsare aggregated at the PS. To improve the efficiency of datasettransmission, we propose two different techniques: increasedcomputation-per-client and sequential data transmission. TheHFCL frameworks outperform FL with up to20%improvementin the learning accuracy when only half of the clients perform FLwhile having50%less communication overhead than CL since allthe clients collaborate on the learning process with their datasets. [less ▲]

An uncertain future for EU-Level Collective Bargaining: the new rules of the game after EPSU

in Industrial Law Journal (2022), 51(2), 318-345

The General Court of the European Union (GCEU) in EPSU and Goudriaan vs. Commission and the Court of Justice of the European Union (CJEU) in the subsequent appeal judgment reached an identical conclusion ... [more ▼]

The General Court of the European Union (GCEU) in EPSU and Goudriaan vs. Commission and the Court of Justice of the European Union (CJEU) in the subsequent appeal judgment reached an identical conclusion on a key aspect of the system of EU level collective bargaining. The Courts held that Article 155(2) of the Treaty on the Functioning of the European Union (TFEU) does not impose any obligation on the European Commission to send a social partner agreement to the Council. This is in line with the Commission’s recent interpretation of Article 155(2) TFEU that subordinates the implementation of the European agreements to a positive assessment of their appropriateness. This article critically assesses the GCEU and CJEU rulings in EPSU and argues that they confirm a major break with the praxis of European collective bargaining that will have negative consequences for the social partners’ autonomy and role in the EU. In order to better understand this break, the article examines how and when the Commission changed its approach to European social dialogue, resulting in the new interpretation of Article 155(2) TFEU, and proposes a hypothesis to understand why. The article concludes by describing the consequences of the new reading of Article 155(2) TFEU for the idea of collective autonomy in EU law as well as for the practice of EU level social dialogue and collective bargaining. [less ▲]

Estimating Probabilistic Safe WCET Ranges of Real-Time Systems at Design Stages

in ACM Transactions on Software Engineering and Methodology (2022)

Estimating worst-case execution times (WCET) is an important activity at early design stages of real-time systems. Based on WCET estimates, engineers make design and implementation decisions to ensure ... [more ▼]

Estimating worst-case execution times (WCET) is an important activity at early design stages of real-time systems. Based on WCET estimates, engineers make design and implementation decisions to ensure that task execution always complete before their specified deadlines. However, in practice, engineers often cannot provide precise point WCET estimates and prefer to provide plausible WCET ranges. Given a set of real-time tasks with such ranges, we provide an automated technique to determine for what WCET values the system is likely to meet its deadlines, and hence operate safely with a probabilistic guarantee. Our approach combines a search algorithm for generating worst-case scheduling scenarios with polynomial logistic regression for inferring probabilistic safe WCET ranges. We evaluated our approach by applying it to three industrial systems from different domains and several synthetic systems. Our approach efficiently and accurately estimates probabilistic safe WCET ranges within which deadlines are likely to be satisfied with a high degree of confidence. [less ▲]

GBA-associated PD: chances and obstacles for targeted treatment strategies.

in Journal of neural transmission (Vienna, Austria : 1996) (2022), 129(9), 1219-1233

Given the clear role of GBA in the pathogenesis of Parkinson's disease (PD) and its impact on phenotypical characteristics, this review provides an overview of the current knowledge of GBA-associated PD ... [more ▼]

Given the clear role of GBA in the pathogenesis of Parkinson's disease (PD) and its impact on phenotypical characteristics, this review provides an overview of the current knowledge of GBA-associated PD with a special focus on clinical trajectories and the underlying pathological mechanisms. Importantly, differences and characteristics based on mutation severity are recognized, and current as well as potential future treatment options are discussed. These findings will inform future strategies for patient stratification and cohort enrichment as well as suitable outcome measures when designing clinical trials. [less ▲]

On the use of commit-relevant mutants

in Empirical Software Engineering (2022), 27

Applying mutation testing to test subtle program changes, such as program patches or other small-scale code modifications, requires using mutants that capture the delta of the altered behaviours. To ... [more ▼]

Applying mutation testing to test subtle program changes, such as program patches or other small-scale code modifications, requires using mutants that capture the delta of the altered behaviours. To address this issue, we introduce the concept of commit-relevant mutants, which are the mutants that interact with the behaviours of the system affected by a particular commit. Therefore, commit-aware mutation testing, is a test assessment metric tailored to a specific commit. By analysing 83 commits from 25 projects involving 2,253,610 mutants in both C and Java, we identify the commit-relevant mutants and explore their relationship with other categories of mutants. Our results show that commit-relevant mutants represent a small subset of all mutants, which differs from the other classes of mutants (subsuming and hard-to-kill), and that the commit-relevant mutation score is weakly correlated with the traditional mutation score (Kendall/Pearson 0.15-0.4). Moreover, commit-aware mutation analysis provides insights about the testing of a commit, which can be more efficient than the classical mutation analysis; in our experiments, by analysing the same number of mutants, commit-aware mutants have better fault-revelation potential (30% higher chances of revealing commit-introducing faults) than traditional mutants. We also illustrate a possible application of commit-aware mutation testing as a metric to evaluate test case prioritisation. [less ▲]

Disentangled Face Identity Representationsfor Joint 3D Face Recognition and Neutralisation

in 2022 8th International Conference on Virtual Reality (2022)

In this paper, we propose a new deep learning based approach for disentangling face identity representations from expressive 3D faces. Given a 3D face, our approach not only extracts a disentangled ... [more ▼]

In this paper, we propose a new deep learning based approach for disentangling face identity representations from expressive 3D faces. Given a 3D face, our approach not only extracts a disentangled identity representation, but also generates a realistic 3D face with a neutral expression while predicting its identity. The proposed network consists of three components; (1) a Graph Convolutional Autoencoder (GCA) to encode the 3D faces into latent representations, (2) a Generative Adversarial Network (GAN) that translates the latent representations of expressive faces into those of neutral faces, (3) and an identity recognition sub-network taking advantage of the neutralized latent representations for 3D face recognition. The whole network is trained in an end-to-end manner. Experiments are conducted on three publicly available datasets showing the effectiveness of the proposed approach. [less ▲]

Genome-wide Association and Meta-analysis of Age-at-Onset in Parkinson Disease: Evidence From COURAGE-PD Consortium 10.1212/WNL.0000000000200699

in Neurology (2022)

Background and Objectives: Considerable heterogeneity exists in the literature concerning genetic determinants of the age of onset (AAO) of Parkinson\textquoterights disease (PD), which could be ... [more ▼]

Background and Objectives: Considerable heterogeneity exists in the literature concerning genetic determinants of the age of onset (AAO) of Parkinson\textquoterights disease (PD), which could be attributed to lack of well-powered replication cohorts. The previous largest GWAS identified SNCA and TMEM175 loci on chromosome (Chr) 4 with a significant influence on AAO of PD, these have not been independently replicated. The present study aims to conduct a meta-analysis of GWAS of PD AAO and validate previously observed findings in worldwide populations.Methods: A meta-analysis was performed on PD AAO GWAS of 30 populations of predominantly European ancestry from the Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in Parkinson\textquoterights Disease (COURAGE-PD) consortium. This was followed up by combining our study with the largest publicly available European ancestry dataset compiled by the International Parkinson disease Genomics Consortium (IPDGC).Results: The COURAGE-PD included a cohort of 8,535 patients with PD (91.9\%: Europeans, 9.1\%: East-Asians). The average AAO in the COURAGE-PD dataset was 58.9 years (SD=11.6), with an under-representation of females (40.2\%). The heritability estimate for AAO in COURAGE-PD was 0.083 (SE=0.057). None of the loci reached genome-wide significance (P\<5x10-8). Nevertheless, the COURAGE-PD dataset confirmed the role of the previously published TMEM175 variant as genetic determinant of AAO of PD with Bonferroni-corrected nominal levels of significance (P\<0.025): (rs34311866:β(SE)COURAGE=0.477(0.203), PCOURAGE=0.0185). The subsequent meta-analysis of COURAGE-PD and IPDGC datasets (Ntotal=25,950) led to the identification of two genome-wide significant association signals on Chr 4, including the previously reported SNCA locus (rs983361:β(SE)COURAGE+IPDGC=0.720(0.122), PCOURAGE+IPDGC=3.13x10-9) and a novel BST1 locus (rs4698412:β(SE)COURAGE+IPDGC=-0.526(0.096), PCOURAGE+IPDGC=4.41x10-8).Discussion: Our study further refines the genetic architecture of Chr 4 underlying the AAO of the PD phenotype through the identification of BST1 as a novel AAO PD locus. These findings open a new direction for the development of treatments to delay the onset of PD. [less ▲]

PARK7/DJ-1 promotes pyruvate dehydrogenase activity and maintains T(reg) homeostasis during ageing.

in Nature metabolism (2022), 4(5), 589-607

Pyruvate dehydrogenase (PDH) is the gatekeeper enzyme of the tricarboxylic acid (TCA) cycle. Here we show that the deglycase DJ-1 (encoded by PARK7, a key familial Parkinson's disease gene) is a pacemaker ... [more ▼]

Pyruvate dehydrogenase (PDH) is the gatekeeper enzyme of the tricarboxylic acid (TCA) cycle. Here we show that the deglycase DJ-1 (encoded by PARK7, a key familial Parkinson's disease gene) is a pacemaker regulating PDH activity in CD4(+) regulatory T cells (T(reg) cells). DJ-1 binds to PDHE1-β (PDHB), inhibiting phosphorylation of PDHE1-α (PDHA), thus promoting PDH activity and oxidative phosphorylation (OXPHOS). Park7 (Dj-1) deletion impairs T(reg) survival starting in young mice and reduces T(reg) homeostatic proliferation and cellularity only in aged mice. This leads to increased severity in aged mice during the remission of experimental autoimmune encephalomyelitis (EAE). Dj-1 deletion also compromises differentiation of inducible T(reg) cells especially in aged mice, and the impairment occurs via regulation of PDHB. These findings provide unforeseen insight into the complicated regulatory machinery of the PDH complex. As T(reg) homeostasis is dysregulated in many complex diseases, the DJ-1-PDHB axis represents a potential target to maintain or re-establish T(reg) homeostasis. [less ▲]

Strategic Forecasting Toward Achieving Defensible Space Architecture by Year 2030

in Journal of Spacecraft and Rockets (2022), 59(5),

Along with the increased demand for space access transportation, a rise in adversarial offensive capabilities, and increasing reliance upon space-based assets, U.S. space assets are now more vulnerable to ... [more ▼]

Along with the increased demand for space access transportation, a rise in adversarial offensive capabilities, and increasing reliance upon space-based assets, U.S. space assets are now more vulnerable to ground- and space-based threats than ever. The U.S. Air Force in its Fiscal Year Posture Statement 2018 recognized that meeting the space threat remains a U.S. Air Force priority for national security. This, along with the creation of a new Space Force, provides more interest in space defense and detailed space architecture development. This needs to be approached pragmatically and strategically. For this, there is a need for a cohesive plan that will support the continued integration and normalization of space in the joint war-fighting environment and places a high priority on space to ensure that U.S. space systems continue to operate in a contested environment. The goal of this study is to identify the national security transportation capabilities and supporting assets needed to establish a superior force in space by the year of 2030 and beyond. Additionally, the science and technology areas that are needed to develop these capabilities are identified, and a strategic space transportation roadmap is generated. [less ▲]

Polygenic Resilience Modulates the Penetrance of Parkinson Disease Genetic Risk Factors

in Annals of Neurology (2022)

Objective: The aim of the current study is to understand why some individuals avoid developing Parkinson disease (PD) despite being at relatively high genetic risk, using the largest datasets of ... [more ▼]

Objective: The aim of the current study is to understand why some individuals avoid developing Parkinson disease (PD) despite being at relatively high genetic risk, using the largest datasets of individual-level genetic data available. Methods: We calculated polygenic risk score to identify controls and matched PD cases with the highest burden of genetic risk for PD in the discovery cohort (International Parkinson's Disease Genomics Consortium, 7,204 PD cases and 9,412 controls) and validation cohorts (Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in Parkinson's Disease, 8,968 cases and 7,598 controls; UK Biobank, 2,639 PD cases and 14,301 controls; Accelerating Medicines Partnership–Parkinson's Disease Initiative, 2,248 cases and 2,817 controls). A genome-wide association study meta-analysis was performed on these individuals to understand genetic variation associated with resistance to disease. We further constructed a polygenic resilience score, and performed multimarker analysis of genomic annotation (MAGMA) gene-based analyses and functional enrichment analyses. Results: A higher polygenic resilience score was associated with a lower risk for PD (β = −0.054, standard error [SE] = 0.022, p = 0.013). Although no single locus reached genome-wide significance, MAGMA gene-based analyses nominated TBCA as a putative gene. Furthermore, we estimated the narrow-sense heritability associated with resilience to PD (h2 = 0.081, SE = 0.035, p = 0.0003). Subsequent functional enrichment analysis highlighted histone methylation as a potential pathway harboring resilience alleles that could mitigate the effects of PD risk loci. Interpretation: The present study represents a novel and comprehensive assessment of heritable genetic variation contributing to PD resistance. We show that a genetic resilience score can modify the penetrance of PD genetic risk factors and therefore protect individuals carrying a high-risk genetic burden from developing PD. ANN NEUROL 2022 [less ▲]

Benchmarking Low-Frequency Variant Calling With Long-Read Data on Mitochondrial DNA

in Frontiers in Genetics (2022), 13

Background: Sequencing quality has improved over the last decade for long-reads, allowing for more accurate detection of somatic low-frequency variants. In this study, we used mixtures of mitochondrial ... [more ▼]

Background: Sequencing quality has improved over the last decade for long-reads, allowing for more accurate detection of somatic low-frequency variants. In this study, we used mixtures of mitochondrial samples with different haplogroups (i.e., a specific set of mitochondrial variants) to investigate the applicability of nanopore sequencing for low-frequency single nucleotide variant detection.Methods: We investigated the impact of base-calling, alignment/mapping, quality control steps, and variant calling by comparing the results to a previously derived short-read gold standard generated on the Illumina NextSeq. For nanopore sequencing, six mixtures of four different haplotypes were prepared, allowing us to reliably check for expected variants at the predefined 5%, 2%, and 1% mixture levels. We used two different versions of Guppy for base-calling, two aligners (i.e., Minimap2 and Ngmlr), and three variant callers (i.e., Mutserve2, Freebayes, and Nanopanel2) to compare low-frequency variants. We used F₁ score measurements to assess the performance of variant calling.Results: We observed a mean read length of 11 kb and a mean overall read quality of 15. Ngmlr showed not only higher F₁ scores but also higher allele frequencies (AF) of false-positive calls across the mixtures (mean F₁ score = 0.83; false-positive allele frequencies < 0.17) compared to Minimap2 (mean F₁ score = 0.82; false-positive AF < 0.06). Mutserve2 had the highest F₁ scores (5% level: F₁ score >0.99, 2% level: F₁ score >0.54, and 1% level: F₁ score >0.70) across all callers and mixture levels.Conclusion: We here present the benchmarking for low-frequency variant calling with nanopore sequencing by identifying current limitations. [less ▲]

EnPlace: Energy-Aware Network Partitioning for Controller Placement in SDN

in IEEE Transactions on Green Communications and Networking (2022)

This paper addresses the energy-aware controller placement problem (CPP) in Software-Defined Networking (SDN), considering the Internet of Things (IoT) flows. CPP involves partitioning the network into ... [more ▼]

This paper addresses the energy-aware controller placement problem (CPP) in Software-Defined Networking (SDN), considering the Internet of Things (IoT) flows. CPP involves partitioning the network into multiple subsets of switches with a single controller assigned to each subset. On the other hand, an energy-aware CPP reduces the energy consumption by link deactivation and ensures that each controller is reachable from the associated switches with a minimal set of active links. Existing literature considers static data traffic and out-of-band control plane having dedicated control links. However, the out-of-band control plane increases the infrastructure cost. Moreover, with IoT devices, SDN experiences uneven data traffic volume due to diverse activation models of the IoT devices. Hence, an energy-aware CPP should consider the effects of dynamic data traffic as improper controller placement and unplanned link deactivation cause link congestion and controller overload. In this work, we present an energy-aware controller placement scheme, named EnPlace, considering in-band control plane and IoT traffic. Additionally, we propose an energy-aware route selection scheme for existing flows. EnPlace increases energy savings significantly as compared to the existing works. In particular, for 200 IoT devices, the proposed scheme increases energy savings by 22.74% as compared to GreCo, an existing scheme. [less ▲]

Visual and biometric surveillance in the EU. Saying ‘no’ to mass surveillance practices?

in Information Polity (2022)

Earlier this year, the European Commission (EC) registered the ‘Civil society initiative for a ban on biometric mass surveillance practices’, a European Citizens’ Initiative. Citizens are thus given the ... [more ▼]

Earlier this year, the European Commission (EC) registered the ‘Civil society initiative for a ban on biometric mass surveillance practices’, a European Citizens’ Initiative. Citizens are thus given the opportunity to authorize the EC to suggest the adoption of legislative instruments to permanently ban biometric mass surveillance practices. This contribution finds the above initiative particularly promising, as part of a new development of bans in the European Union (EU). It analyses the EU’s approach to facial, visual and biometric surveillance, with the objective of submitting some ideas that the European legislator could consider when strictly regulating such practices. [less ▲]

iBiR: Bug Report driven Fault Injection

in ACM Transactions on Software Engineering and Methodology (2022)

Mutation Testing in Evolving Systems: Studying the relevance of mutants to code evolution

in ACM Transactions on Software Engineering and Methodology (2022)

Context: When software evolves, opportunities for introducing faults appear. Therefore, it is important to test the evolved program behaviors during each evolution cycle. However, while software evolves ... [more ▼]

Context: When software evolves, opportunities for introducing faults appear. Therefore, it is important to test the evolved program behaviors during each evolution cycle. However, while software evolves, its complexity is also evolving, introducing challenges to the testing process. To deal with this issue, testing techniques should be adapted to target the effect of the program changes instead of the entire program functionality. To this end, commit-aware mutation testing, a powerful testing technique, has been proposed. Unfortunately, commit-aware mutation testing is challenging due to the complex program semantics involved. Hence, it is pertinent to understand the characteristics, predictability, and potential of the technique. Objective: We conduct an exploratory study to investigate the properties of commit-relevant mutants, i.e., the test elements of commit-aware mutation testing, by proposing a general definition and an experimental approach to identify them. We thus, aim at investigating the prevalence, location, and comparative advantages of commit-aware mutation testing over time (i.e., the program evolution). We also investigate the predictive power of several commit-related features in identifying and selecting commit-relevant mutants to understand the essential properties for its best-effort application case. Method: Our commit-relevant definition relies on the notion of observational slicing, approximated by higher-order mutation. Specifically, our approach utilizes the impact of mutants, effects of one mutant on another in capturing and analyzing the implicit interactions between the changed and unchanged code parts. The study analyses millions of mutants (over 10 million), 288 commits, five (5) different open-source software projects involving over 68,213 CPU days of computation and sets a ground truth where we perform our analysis. Results: Our analysis shows that commit-relevant mutants are located mainly outside of program commit change (81%), suggesting a limitation in previous work. We also note that effective selection of commit-relevant mutants has the potential of reducing the number of mutants by up to 93%. In addition, we demonstrate that commit relevant mutation testing is significantly more effective and efficient than state-of-the-art baselines, i.e., random mutant selection and analysis of only mutants within the program change. In our analysis of the predictive power of mutants and commit-related features (e.g., number of mutants within a change, mutant type, and commit size) in predicting commit-relevant mutants, we found that most proxy features do not reliably predict commit-relevant mutants. Conclusion: This empirical study highlights the properties of commit-relevant mutants and demonstrates the importance of identifying and selecting commit-relevant mutants when testing evolving software systems. [less ▲]

How green are our laws? Presenting a normative coherence for sustainable development methodology

in Environmental Policy and Governance (2022)

Policy coherence for sustainable development (PCSD) has become a pillar of supranational sustainable development agendas, promoting “whole of government approaches.” The concept of normative coherence for ... [more ▼]

Policy coherence for sustainable development (PCSD) has become a pillar of supranational sustainable development agendas, promoting “whole of government approaches.” The concept of normative coherence for sustainable development (NCSD) has emerged as a new stage of policy coherence for sustainable development analysis. NCSD is a policy approach that aims to promote transformative development by examining the relationship between policies and key sustainability norms, such as those expressed in the sustainable development goals. Normative coherence for sustainable development is recognized in recent scholarship but it remains generalized, lacking operationalization. This article proposes an NCSD methodology for analysis of legal frameworks. Qualitative empirical research tested this approach in Mexico by focusing on federal laws as well as those in two states: Aguascalientes and Veracruz. The analysis which examined four dimensions of sustainable development (economic, social, security, and environmental) showed that the environmental dimension of Mexico's legal framework is the least prioritized, suggesting that this framework is not very “green” even though environmental laws are the most transversal in content, which indicate significant levels of mainstreaming. Sustainable development experts were then contacted by the research team to validate the findings and interpret the results. This normative coherence for sustainable development methodology aims to situate normative considerations at the center of evaluation in order to promote domestic transformative sustainable development strategies and the “greening” of legal frameworks. [less ▲]

How sensitive are the evaluations of a school's effectiveness to the selection of covariates in the applied value‑added model?

in Educational Assessment, Evaluation and Accountability (2022)

There is no final consensus regarding which covariates should be used (in addition to prior achievement) when estimating value-added (VA) scores to evaluate a school’s effectiveness. Therefore, we ... [more ▼]

There is no final consensus regarding which covariates should be used (in addition to prior achievement) when estimating value-added (VA) scores to evaluate a school’s effectiveness. Therefore, we examined the sensitivity of evaluations of schools’ effectiveness in math and language achievement to covariate selection in the applied VA model. Four covariate sets were systematically combined, including prior achievement from the same or different domain, sociodemographic and sociocultural background characteristics, and domain-specific achievement motivation. School VA scores were estimated using longitudinal data from the Luxembourg School Monitoring Programme with some 3600 students attending 153 primary schools in Grades 1 and 3. VA scores varied considerably, despite high correlations between VA scores based on the different sets of covariates (.66 < r < 1.00). The explained variance and consistency of school VA scores substantially improved when including prior math and prior language achievement in VA models for math and prior language achievement with sociodemographic and sociocultural background characteristics in VA models for language. These findings suggest that prior achievement in the same subject, the most commonly used covariate to date, may be insufficient to control for between-school differences in student intake when estimating school VA scores. We thus recommend using VA models with caution and applying VA scores for informative purposes rather than as a mean to base accountability decisions upon. [less ▲]

LL(O)D and NLP perspectives on semantic change for humanities research

in Semantic Web (2022)

This paper presents an overview of the LL(O)D and NLP methods, tools and data for detecting and representing semantic change, with its main application in humanities research. The paper’s aim is to ... [more ▼]

This paper presents an overview of the LL(O)D and NLP methods, tools and data for detecting and representing semantic change, with its main application in humanities research. The paper’s aim is to provide the starting point for the construction of a workflow and set of multilingual diachronic ontologies within the humanities use case of the COST Action Nexus Linguarum, European network for Web-centred linguistic data science, CA18209. The survey focuses on the essential aspects needed to understand the current trends and to build applications in this area of study. [less ▲]

Driver’s Face Pose Estimation Using Fine-Grained Wi-Fi Signals for Next-Generation Internet of Vehicles

in Wireless Communications and Mobile Computing (2022), 2022

Driver’s behavior and gesture recognition are most significant in the emerging next-generation vehicular technology. Driver’s face may provide important cues about his/her attention and fatigue behavior ... [more ▼]

Driver’s behavior and gesture recognition are most significant in the emerging next-generation vehicular technology. Driver’s face may provide important cues about his/her attention and fatigue behavior. Therefore, driver’s face pose is one of the key indicators to be considered for automatic driver monitoring system in next-generation Internet of Vehicles (IoV) technology. Driver behavior monitoring is most significant in order to reduce road accidents. This paper aims to address the problem of driver’s attentiveness monitoring using face pose estimation in a nonintrusive manner. The proposed system is based on wireless sensing, leveraging channel state information (CSI) of WiFi signals. In this paper, we present a novel classification algorithm that is based on the combination of support vector machine (SVM) and K nearest neighbor (KNN) to enhance the classification accuracy. Experimental results demonstrate that the proposed device-free wireless implementation can localize a driver’s face very accurately with an average recognition rate of 91:8%. [less ▲]

Aiding Reflective Navigation in a Dynamic Information Landscape: A Challenge for Educational Psychology

in Frontiers in Psychology (2022)

Open access to information is now a universal phenomenon thanks to rapid technological developments across the globe. This open and universal access to information is a key value of democratic societies ... [more ▼]

Open access to information is now a universal phenomenon thanks to rapid technological developments across the globe. This open and universal access to information is a key value of democratic societies because, in principle, it supports well-informed decision-making on individual, local, and global matters. In practice, however, without appropriate readiness for navigation in a dynamic information landscape, such access to information can become a threat to public health, safety, and economy, as the COVID-19 pandemic has shown. In the past, this readiness was often conceptualized in terms of adequate literacy levels, but the contemporarily observed highest-ever literacy levels have not immunized our societies against the risks of misinformation. Therefore, in this Perspective, we argue that democratisation of access to information endows citizens with new responsibilities, and second, these responsibilities demand readiness that cannot be reduced to mere literacy levels. In fact, this readiness builds on individual adequate literacy skills, but also requires rational thinking and awareness of own information processing. We gather evidence from developmental, educational, and cognitive psychology to show how these aspects of readiness could be improved through education interventions, and how they may be related to healthy work-home balance and self-efficacy. All these components of education are critical to responsible global citizenship and will determine the future direction of our societies. [less ▲]

Every Student Can Learn, Just not on the Same Day: An Analysis of Data Protection and Cybersecurity Challenges for E-Learning Platforms in the COVID19 Crisis

in European Journal of Law and Technology (2022), 13(1),

A Cost-Effective Identity-Based Signature Scheme for Vehicular Ad Hoc Network Using Hyperelliptic Curve Cryptography

in Wireless Communications and Mobile Computing (2022)

A Vehicular Ad Hoc Network (VANET) is a subset of the Mobile Ad Hoc Network (MANET) that allows vehicles to communicate with each other and with roadside stations to offer efficient and safe ... [more ▼]

A Vehicular Ad Hoc Network (VANET) is a subset of the Mobile Ad Hoc Network (MANET) that allows vehicles to communicate with each other and with roadside stations to offer efficient and safe transportation. Furthermore, when VANET is used in connection with the Internet of Things (IoT) devices and sensors, it can help with traffic management and road safety by allowing vehicles to interact with one another at any time and from any location. Since VANET’s event-driven communications are carried out via an open wireless channel, there are significant security concerns. In this paper, we use Hyperelliptic Curve Cryptography (HECC) to offer a cost-effective identity-based signature for secure communication over VANET. The proposed scheme does not need certificate management, and we found that it is more secure against a variety of cryptographic threats after conducting a thorough security analysis. In addition, comparisons of communication and computational costs are made, demonstrating that the proposed scheme is more efficient in both respects than existing schemes. [less ▲]

La spécialisation linguistique de l 'emploi au Luxembourg étudiée à travers les offres d'emploi (1984-2019) Rapport de synthèse

in UniGR_CBS Working Paper (2022), 13

Based on a sample of job advertisements published in the main Luxembourgish daily newspaper (Luxem-burger Wort) covering the period 1984-2019, this study describes the development of language skills re ... [more ▼]

Based on a sample of job advertisements published in the main Luxembourgish daily newspaper (Luxem-burger Wort) covering the period 1984-2019, this study describes the development of language skills re-quired on the Luxembourg job market. After a brief presentation of the linguistic situation and the labor market in Luxembourg, the statistical analysis of a sample of some 8,340 job advertisements constitutes the main part of this publication. A qualitative study of a smaller body of job vacancies sheds additional light and a detailed understanding of linguistic needs in a multilingual and international labor market. Both approaches come to the same conclusion. The labor shortage and particularly the lack of people fluent in the "three languages of the country" has led to a segmentation of the labor market. [less ▲]

Reconfigurable Intelligent Surface-Assisted Massive MIMO: Favorable propagation, channel hardening, and rank deficiency

in IEEE Signal Processing Magazine (2022), 39(3),

Massive multiple-input multiple-output (MIMO) and reconfigurable intelligent surface (RIS) are two promising technologies for 5G-and-beyond wireless networks, capable of providing large array gain and ... [more ▼]

Massive multiple-input multiple-output (MIMO) and reconfigurable intelligent surface (RIS) are two promising technologies for 5G-and-beyond wireless networks, capable of providing large array gain and multiuser spatial multiplexing. Without requiring additional frequency bands, those technologies offer significant improvements in both spectral and energy efficiency by simultaneously serving many users. The performance analysis of an RIS-assisted massive MIMO system as a function of channel statistics relies heavily on fundamental properties, including favorable propagation, channel hardening, and rank deficiency. The coexistence of both direct and indirect links results in aggregated channels, whose properties are the main concerns of this “Lecture Notes” article. For practical systems with a finite number of antennas and engineered scattering elements of the RIS, we evaluate the corresponding deterministic metrics, with Rayleigh fading channels as a typical example. [less ▲]

THz-Empowered UAVs in 6G: Opportunities, Challenges, and Trade-Offs

in IEEE Communications Magazine (2022), 60(5), 24-30

Envisioned use cases of unmanned aerial vehicles (UAVs) impose new service requirements in terms of data rate, latency, and sensing accuracy, to name a few. If such requirements are satisfactorily met, it ... [more ▼]

Envisioned use cases of unmanned aerial vehicles (UAVs) impose new service requirements in terms of data rate, latency, and sensing accuracy, to name a few. If such requirements are satisfactorily met, it can create novel applications and enable highly reliable and harmonized integration of UAVs in the 6G network ecosystem. Towards this, terahertz (THz) bands are perceived as a prospective technological enabler for various improved functionalities such as ultra-high throughput and enhanced sensing capabilities. This paper focuses on THz-empowered UAVs with the following capabilities: communication, sensing, localization, imaging, and control. We review the potential opportunities and use cases of THz-empowered UAVs, corresponding novel design challenges, and resulting trade-offs. Furthermore, we overview recent advances in UAV deployments regulations, THz standardization, and health aspects related to THz bands. Finally, we take UAV to UAV (U2U) communication as a case-study to provide numerical insights into the impact of various system design parameters and environment factors. [less ▲]

User selection for massive MIMO under line-of-sight propagation

in IEEE Open Journal of the Communications Society (2022)

This paper provides a review of user selection algorithms for massive multiple-input multiple-output (MIMO) systems under the line-of-sight (LoS) propagation model. Although the LoS propagation is ... [more ▼]

This paper provides a review of user selection algorithms for massive multiple-input multiple-output (MIMO) systems under the line-of-sight (LoS) propagation model. Although the LoS propagation is extremely important to some promising technologies, like in millimeter-wave communications, massive MIMO systems are rarely studied under this propagation model. This paper fills this gap by providing a comprehensive study encompassing several user selection algorithms, different linear precoders and simulation setups, and also considers the effect of partial channel state information (CSI). One important result is the existence of practical cases in which the LoS propagation model may lead to significant levels of interference among users within a cell; these cases are not satisfactorily addressed by the existing user selection algorithms. Motivated by this issue, a new user selection algorithm based on inter-channel interference (ICI) called ICI-based selection (ICIBS) is proposed. Unlike other techniques, the ICIBS accounts for the ICI in a global manner, thus yielding better results, especially in cases where there are many users interfering with each other. In such scenarios, simulation results show that when compared to the competing algorithms, the proposed approach provided an improvement of at least 10.9% in the maximum throughput and 7.7% in the 95%-probability throughput when half of the users were selected. [less ▲]