Last 7 days
Bookmark and Share    
Full Text
Peer Reviewed
See detailEnergy-Efficient Backscatter Aided Uplink NOMA Roadside Sensor Communications under Channel Estimation Errors
Ihsan, Asim; Chen, Wen; Khan, Wali Ullah UL et al

in IEEE Transactions on Intelligent Transportation Systems (2023)

This work presents non-orthogonal multiple access (NOMA) enabled energy-efficient alternating optimization framework for backscatter aided wireless powered uplink sensors communications for beyond 5G ... [more ▼]

This work presents non-orthogonal multiple access (NOMA) enabled energy-efficient alternating optimization framework for backscatter aided wireless powered uplink sensors communications for beyond 5G intelligent transportation system (ITS). Specifically, the transmit power of carrier emitter (CE) and reflection coefficients of backscatter aided roadside sensors are optimized with channel uncertainties for the maximization of the energy efficiency (EE) of the network. The formulated problem is tackled by the proposed two-stage alternating optimization algorithm named AOBWS (alternating optimization for backscatter aided wireless powered sensors). In the first stage, AOBWS employs an iterative algorithm to obtain optimal CE transmit power through simplified closed-form computed through Cardano’s formulae. In the second stage, AOBWS uses a noniterative algorithm that provides a closed-form expression for the computation of optimal reflection coefficient for roadside sensors under their quality of service (QoS) and a circuit power constraint. The global optimal exhaustive search (ES) algorithm is used as a benchmark. Simulation results demonstrate that the AOBWS algorithm can achieve near-optimal performance with very low complexity, which makes it suitable for practical implementations. [less ▲]

Full Text
Peer Reviewed
See detailArbitrage bots in experimental asset markets
Neugebauer, Tibor UL

in Journal of Economic Behavior and Organization (2023), 206

Trading algorithms are an integral component of modern asset markets. In twin experimental markets for long-lived correlated assets we examine the impact of alternative types of arbitrage-seeking ... [more ▼]

Trading algorithms are an integral component of modern asset markets. In twin experimental markets for long-lived correlated assets we examine the impact of alternative types of arbitrage-seeking algorithms. These arbitrage robot traders vary in their latency and whether they make or take market liquidity. All arbitrage robot traders we examine generate greater conformity to the law-of-one-price across the twin markets. However, only the liquidity providing arbitrage robot trader moves prices into closer alignment with fundamental values. The reduced mispricing comes with varying social costs; arbitrage robot traders’ gains reduce the earnings of human traders. We identify factors which drive differences in human trader performance and find that the presence of an arbitrage robot trader has no disproportionate effect with respect to these factors on subjects’ earnings. [less ▲]

See detailPolicy Brief to the French Public Consultation on Influencers and Content Creators
Aade, Laura UL; Goanta, Catalina; van de Kerkhof, Jacob

Diverse speeches and writings (2023)

Full Text
Peer Reviewed
See detailConsonant and Dissonant Experiences—Young Migrants’ Un-derstandings of Integration: A Cross-Country Comparison between Germany, Luxembourg, and Norway.
Biaback Anong, Dorothea; Skrobanek, Jan; Wagner, Leonie et al

in Social Sciences (2023), 12

Our article addresses two aspects of young migrants’ understandings of integration: their own ideas of what integration is, and their perception of the destination society’s concepts and expectations ... [more ▼]

Our article addresses two aspects of young migrants’ understandings of integration: their own ideas of what integration is, and their perception of the destination society’s concepts and expectations regarding their integration. We analyze qualitative interviews which were conducted in the Horizon 2020 project MIMY, in Germany, Luxembourg and Norway, using the grounded theory methodology. Our exploration shows that the young migrants’ awareness of the existing ideas of integration surrounding them creates a complex reflective interaction between their own ideas and the (perceived) expectations from society. We identified aspects of consonance, where young migrants’ ideas coincide with the expectations they perceive. More importantly, however, our research has discovered that the youth experience tensions and dissonance between their own ideas of what integration should be and the concepts and expectations regarding integration they feel confronted with by society. Our analysis revealed that while young migrants’ understandings of integration are very close to state-of-the-art scientific conceptualizations of integration, this view is not matched by the meaning of integration they perceive around them. [less ▲]

Peer Reviewed
See detailCommercial Space Operators on the Digital Battlefield
Zarkan, Laetitia UL

in CIGI Essay Series: Cybersecurity and Outer Space (2023)

Full Text
See detailLa Grande Stratégie des petites puissances – Etude des mécanismes de fondation d’une grande stratégie face à un dilemme de sécurité appliqués au Luxembourg, à la Lituanie et à Singapour (1965-2025)-
Fouillet, Thibault UL

Doctoral thesis (2023)

The capacity of small powers to think strategically remains a limited field of interest in historical thinking and international relations. Thus, beyond the debate concerning the capacity of small states ... [more ▼]

The capacity of small powers to think strategically remains a limited field of interest in historical thinking and international relations. Thus, beyond the debate concerning the capacity of small states to be full-fledged actors in the international system, there appears to be a denial of the conceptualization and doctrinal innovation capacity of small powers despite the historical redundancy of the victory of the weak over the strong. However, small powers are by nature more sensitive to threats due to their limited response capabilities, and are therefore more inclined to rationalize their action over the long term in order to develop national (military, economic, diplomatic capabilities, etc.) and international (alliances, international organizations, etc.) mechanisms for containing these threats. In this respect, this thesis proposes to look at the construction of the strategic thinking of small powers in the face of perceived threats and the means used to try to contain them. The aim is therefore to study the mechanisms by which small powers found a Grand Strategy (transcribed in the form of doctrines) to deal with the security dilemmas they face. To this end, three case studies were analyzed (Luxembourg, Singapore, Lithuania), chosen for the diversity of their strategic and historical contexts offering a variety of security dilemmas. The Grand Strategy being in essence a conceptual construction with a prospective and applicative aim, a theoretical as well as a practical methodology (through the use of immediate history and wargaming) was then implemented. Two sets of lessons can be drawn from this thesis. The first is methodological, confirming the interest of doctrinal studies as a field of strategic reflection, and establishing wargaming as a prospective tool adapted to the conduct of fundamental research. The second, conceptual, allows for a better understanding of the capacity of small powers to create great and efficient strategies, which must be taken into account within the strategic genealogy because of their conceptual dynamism, which can be used to teach lessons even to great powers. [less ▲]

Full Text
See detailPlanktonic Active Matter
Sengupta, Anupam UL

E-print/Working paper (2023)

Planktonic active matter represents an emergent system spanning different scales: individual, population and community; and complexity arising from sub-cellular and cellular to collective and ecosystem ... [more ▼]

Planktonic active matter represents an emergent system spanning different scales: individual, population and community; and complexity arising from sub-cellular and cellular to collective and ecosystem scale dynamics. This cross-scale active matter system responds to a range of abiotic (temperature, fluid flow and light conditions) and biotic factors (nutrients, pH, secondary metabolites) characteristic to the relevant ecosystems they are part of. Active modulation of cell phenotypes, including morphology, motility, and intracellular organization enable planktonic microbes to dynamically interact with other individuals and species; and adapt - often rapidly - to the changes in their environment. In this chapter, I discuss both traditional and contemporary approaches to study the dynamics of this multi-scale active matter system from a mechanistic standpoint, with specific references to their local settings and their ability to actively tune the behaviour and physiology, and the emergent structures and functions they elicit under natural ecological constraints as well as due to the shifting climatic trends. [less ▲]

See detailREVISITING AND BOOSTING STATE-OF-THE-ART ML-BASED ANDROID MALWARE DETECTORS
Daoudi, Nadia UL

Doctoral thesis (2023)

Android offers plenty of services to mobile users and has gained significant popularity worldwide. The success of Android has resulted in attracting more mobile users but also malware authors. Indeed ... [more ▼]

Android offers plenty of services to mobile users and has gained significant popularity worldwide. The success of Android has resulted in attracting more mobile users but also malware authors. Indeed, attackers target Android markets to spread their malicious apps and infect users’ devices. The consequences vary from displaying annoying ads to gaining financial benefits from users. To overcome the threat posed by Android malware, Machine Learning has been leveraged as a promising technique to automatically detect malware. The literature on Android malware detection lavishes with a huge variety of ML-based approaches that are designed to discriminate malware from legitimate samples. These techniques generally rely on manually engineered features that are extracted from the apps’ artefacts. Reported to be highly effective, Android malware detection approaches seem to be the magical solution to stop the proliferation of malware. Unfortunately, the gap between the promised and the actual detection performance is far from negligible. Despite the rosy excellent detection performance painted in the literature, the detection reports show that Android malware is still spreading and infecting mobile users. In this thesis, we investigate the reasons that impede state-of-the-art Android malware detection approaches to surround the spread of Android malware and propose solutions and directions to boost their detection performance. In the first part of this thesis, we focus on revisiting the state of the art in Android malware detection. Specifically, we conduct a comprehensive study to assess the reproducibility of state-of-the-art Android malware detectors. We consider research papers published at 16 major venues over a period of ten years and report our reproduction outcome. We also discuss the different obstacles to reproducibility and how they can be overcome. Then, we perform an exploratory analysis on a state-of-the-art malware detector, DREBIN, to gain an in-depth understanding of its inner working. Our study provides insights into the quality of DREBIN’s features and their effectiveness in discriminating Android malware. In the second part of this thesis, we investigate novel features for Android malware detection that do not involve manual engineering. Specifically, we propose an Android malware detection approach, DexRay, that relies on features extracted automatically from the apps. We convert the raw bytecode of the app DEX files into an image and train a 1-dimensional convolutional neural network to automatically learn the relevant features. Our approach stands out for the simplicity of its design choices and its high detection performance, which make it a foundational framework for further developing this domain. In the third part, we attempt to push the frontier of Android malware detection via enhancing the detection performance of the state of the art. We show through a large-scale evaluation of four state-of-the-art malware detectors that their detection performance is highly dependent on the experimental dataset. To solve this issue, we investigate the added value of combining their features and predictions using 22 combination methods. While it does not improve the detection performance reported by individual approaches, the combination of features and predictions maintains the highest detection performance independently of the dataset. We further propose a novel technique, Guided Retraining, that boosts the detection performance of state-of-the-art Android malware detectors. Guided Retraining uses contrastive learning to learn a better representation of the difficult samples to improve their prediction. [less ▲]

Full Text
See detailBreakthrough of directional statistics in space science
Palmirotta, Guendalina UL

Speeches/Talks (2023)

It should be no surprise that already back in the 17-18th centuries important foundations of modern statistical theory were formulated to address astronomical problems, the astronomers were the ... [more ▼]

It should be no surprise that already back in the 17-18th centuries important foundations of modern statistical theory were formulated to address astronomical problems, the astronomers were the statisticians. For instance the 'almost coincidence' in the orbits of the planets in our Solar System with the ecliptic has intrigued the scientists for a long time. Even D. Bernoulli (in the 1730's) wondered if this fact could happen 'by chance'. In a statistical framework, one could think of using a uniformity test on the sphere. Testing isotropy or, equivalently, testing uniformity on the unit hypersphere is one of the oldest as well as most fundamental problems in directional statistics and it is still much considered nowadays. Furthermore with the increasing astronomical data, innovative modern directional statistical theories and models have been proposed to deal with space science issues such as tracking space objects. In this talk, we will provide a review of the many old and recent developments of directional statistics animated by interesting applications in space science. This is a joint work with Christophe Ley. [less ▲]

Full Text
Peer Reviewed
See detailFormer refugees’ acculturation processes and their views on newly arrived refugees in Germany
Kämmer, Jana J. L.; Albert, Isabelle UL

in Human Arenas (2023), online first

Research on the rising number of refugees migrating to Germany has seldom considered experiences of refugees who fled to Germany several years ago and went through the process of acculturation themselves ... [more ▼]

Research on the rising number of refugees migrating to Germany has seldom considered experiences of refugees who fled to Germany several years ago and went through the process of acculturation themselves. In the present study, we investigated acculturation processes of former refugees and their views on newly arrived refugees in Germany and discuss the lessons that can be learned by society and the political system from their lived experiences. Semi-structured in-depth interviews were conducted and analyzed by using qualitative content analysis. The sample consisted of five former refugees from the countries Iran, Iraq, and Togo. The results illustrate their acculturation processes in Germany and their attempt to integrate different, sometimes opposing cultures into their everyday lives. Ambivalent opinions on the new arrivals and the integration politics in Germany in 2015/16 (the so-called “refugee crisis”) become visible. On the one hand, empathy and solidarity towards newly arriving refugees are mentioned; on the other hand, worries are expressed and demands are made of them. On the political level, the welcoming attitude is appreciated, but clear regulations are desired. The results strongly suggest that former refugees should be included, and their personal experiences of immigration should be more thoroughly considered in decision making within integration politics. [less ▲]

Full Text
Peer Reviewed
See detailA Metabolomics-Based Investigation of the Effects of a Short-Term Body Weight Reduction Program in a Cohort of Adolescents with Obesity: A Prospective Interventional Clinical Study
Rigamonti, Antonello E.; Frigerio, Gianfranco UL; Caroli, Diana et al

in Nutrients (2023), 15(3), 529

Metabolomics applied to assess the response to a body weight reduction program (BWRP) may generate valuable information concerning the biochemical mechanisms/pathways underlying the BWRP-induced ... [more ▼]

Metabolomics applied to assess the response to a body weight reduction program (BWRP) may generate valuable information concerning the biochemical mechanisms/pathways underlying the BWRP-induced cardiometabolic benefits. The aim of the present study was to establish the BWRP-induced changes in the metabolomic profile that characterizes the obese condition. In particular, a validated liquid chromatography–tandem mass spectrometry (LC–MS/MS) targeted metabolomic approach was used to determine a total of 188 endogenous metabolites in the plasma samples of a cohort of 42 adolescents with obesity (female/male = 32/10; age = 15.94 ± 1.33 year; body mass index standard deviation score (BMI SDS) = 2.96 ± 0.46) who underwent a 3-week BWRP, including hypocaloric diet, physical exercise, nutritional education, and psychological support. The BWRP was capable of significantly improving body composition (e.g., BMI SDS, p < 0.0001), glucometabolic homeostasis (e.g., glucose, p < 0.0001), and cardiovascular function (e.g., diastolic blood pressure, p = 0.016). A total of 64 metabolites were significantly reduced after the intervention (at least p < 0.05), including 53 glycerophospholipids (23 PCs ae, 21 PCs aa, and 9 lysoPCs), 7 amino acids (tyrosine, phenylalanine, arginine, citrulline, tryptophan, glutamic acid, and leucine), the biogenic amine kynurenine, 2 sphingomyelins, and (free) carnitine (C0). On the contrary, three metabolites were significantly increased after the intervention (at least p < 0.05)—in particular, glutamine, trans-4-hydroxyproline, and the octadecenoyl-carnitine (C18:1). In conclusion, when administered to adolescents with obesity, a short-term BWRP is capable of changing the metabolomic profile in the plasma. [less ▲]

Full Text
See detailIntroduction
Pettiau, Hérold UL; Wagner, Anne; Meyer, Frédéric

in Pettiau; Wagner, Anne (Eds.) L'évêque contesté. Les résistances à l'autorité épiscopale des Pays-Bas à l'Italie du Nord (2023)

The study of such a problematic over such a long period, from the tenth to the seventeenth century, adopted by the Lodocat project, needs to be marked out even briefly. The contributions, grouped in four ... [more ▼]

The study of such a problematic over such a long period, from the tenth to the seventeenth century, adopted by the Lodocat project, needs to be marked out even briefly. The contributions, grouped in four thematic and chronological parts, examine the representation of episcopal authority at the local level and the competition between different models of episcopal action. [less ▲]

See detailThe creative process in(between) humans and machines
Gubenko, Alla UL

Doctoral thesis (2023)

Arguably, embodiment is the most neglected aspect of cognitive psychology and creativity research. Whereas most existing theoretical frameworks are inspired by or implicitly imply “cognition as a ... [more ▼]

Arguably, embodiment is the most neglected aspect of cognitive psychology and creativity research. Whereas most existing theoretical frameworks are inspired by or implicitly imply “cognition as a computer” metaphor, depicting creative thought as a disembodied idea generation and processing of amodal symbols, this thesis proposes that “cognition as a robot” may be a better metaphor to understand how creative cognition operates . In this thesis, I compare and investigate human creative cognition in relation to embodied artificial agents that has to learn to navigate and act in complex and changing material and social environments from a set of multimodal streams (e.g., vision, haptic). Instead of relying on divergent thinking or associative accounts of creativity, I attempt to elaborate an embodied and action-oriented vision of creativity grounded in the 4E cognition paradigm. Situated at the intersection of the psychology of creativity, technology, and embodied cognitive science, the thesis attempts to synthesize disparate lines of work and look at a complex problem of human creativity through interdisciplinary lenses. In this perspective, the study of creativity is no longer a prerogative of social scientists but a collective and synergistic endeavor of psychologists, engineers, designers, and computer scientists. [less ▲]