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See detailStudy of nanopulsed discharges for plasma-polymerization: experimental characterization and theoretical understanding of growth mechanisms in the deposition of functional polymer thin films
Loyer, François UL

Doctoral thesis (2019)

Plasma processes are highly versatile methods able to promote the formation of thin films from a vast variety of compounds thanks to the numerous energetic species they generate. Notably, plasma-enhanced ... [more ▼]

Plasma processes are highly versatile methods able to promote the formation of thin films from a vast variety of compounds thanks to the numerous energetic species they generate. Notably, plasma-enhanced chemical vapor deposition (PECVD) processes have already led to the simultaneous synthesis and deposition of a wide variety of organic functional materials. Reciprocally, the many reactive species composing the plasma induce a non-negligible number of side reactions, yielding altered chemistry compared to conventional polymerization processes. Therefore, there is a strong need for controlled methods promoting conventional polymerization pathway in plasma-based processes to increase their range of application. To this end, the atmospheric-pressure plasma-initiated chemical vapor deposition (AP-PiCVD) process was developed, differing from classical PECVD by its initiation source. AP-PiCVD relies on square-wave nanopulsed discharges with single ultra-short plasma on times (t_on ≈ 100 ns) and long plasma off-times (t_off = 0.1 – 100 ms) rather than alternative current sources yielding long and repeated discharges (t_on = 10 µs). Methacrylate monomers initiated by nanopulsed discharges highlighted a shift of growth mechanisms from classical PECVD pathways (plasma-polymerization) to conventional free-radical polymerization. Notably, the growth of polymer layers with an extremely high retention of the monomer’s chemistry and unprecedented molecular weights for an atmospheric-pressure plasma process is demonstrated at long plasma off-times. Moreover, a transition from gas phase to surface growth mechanisms is observed, allowing the deposition of conformal coatings similarly to low-pressure alternative chemical vapor deposition processes. A thorough investigation of the thin films’ chemistry confirms the conventional nature of the layers grown by AP-PiCVD and shed light upon the growth mechanisms in low-frequency nanosecond pulsed plasmas. While the on-time induces the formation of free radicals from the monomers’ fragmentation which are able to initiate and terminate the chain addition process, conventional polymerization mechanisms are strongly promoted during the off-time yielding linear polymer core. Interestingly, new insights on selective initiation mechanisms based on sacrificial functions for an enhanced control of the molecular fragmentation are put forward and discussed. The development of a model describing the kinetic of pulsed plasma was carried out and correlated with experimental observations, providing deeper understanding of the interaction between the gas phase and the surface. The extraction of important physical parameters for the description of the growth kinetics in AP-PiCVD is demonstrated and their significance discussed. Using the fundamental knowledge developed on nanosecond pulsed plasma-initiated polymerization mechanisms, thermoresponsive copolymer layers grown by AP-PiCVD are reported for the first time. The properties of the layers are evaluated and related to their chemistry, allowing the determination of an optimal co-monomers ratio to integrate both of their individual properties as a unique functional thin film. [less ▲]

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See detailWind music and scholarship. IGEB and WASBE
Sagrillo, Damien UL

Scientific Conference (2019, July 13)

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See detailLe millefeuille temporel des archives du Web
Schafer, Valerie UL

Presentation (2019, July 11)

À partir d’exemples choisis au sein des archives du Web et des réseaux socio-numériques, cette intervention se propose de montrer les différentes strates temporelles à l’œuvre au sein de ce patrimoine dit ... [more ▼]

À partir d’exemples choisis au sein des archives du Web et des réseaux socio-numériques, cette intervention se propose de montrer les différentes strates temporelles à l’œuvre au sein de ce patrimoine dit « nativement numérique », et ce de la sélection et collecte à l’analyse, en passant par l’accès via les interfaces et les médiations qu’elles introduisent, l’enrichissement via des métadonnées ou l’intégration d’outils de fouille. [less ▲]

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See detailRecent Activities on Tristan da Cunha Island: Geodetic Installations, Local Tie Measurements and their Analysis
Teferle, Felix Norman UL; Hunegnaw, Addisu UL; Backes, Dietmar UL et al

Scientific Conference (2019, July 11)

During 2017 a team from the University of Luxembourg and the National Oceanography Centre, Liverpool, established a permanent Global Navigation Satellite System (GNSS) station and two new tide gauges on ... [more ▼]

During 2017 a team from the University of Luxembourg and the National Oceanography Centre, Liverpool, established a permanent Global Navigation Satellite System (GNSS) station and two new tide gauges on Tristan da Cunha Island in the South Atlantic Ocean. These installations were funded through various projects at both collaborating institutions under the umbrella of the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group and the Global Geodetic Observing System (GGOS) focus area on Sea Level Change, Variability and Forecasting. While this was the first scientific installation of a GNSS station on the main island within the Tristan da Cunha archipelago, IGS station GOUG, located on Gough Island which lies 412 km to the south, has been in operation since 1998. Unfortunately GOUG was decommissioned in 2018. Sea level observations on Tristan da Cunha have a longer history than GNSS with various tide gauges having been in operation since 1984. Tristan da Cunha also hosts a Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) station which was established in 2012 after a previous installation was upgraded and moved to the current site. The antenna TCTA is located on the concrete monument of the previous DORIS antenna. Furthermore, in order for future International Terrestrial Reference Frame (ITRF) computations to fully benefit from the proximity of the sensors, the geodetic ties between the respective antennas (and reference markers in case of the tide gauges) need to be determined at the millimeter level using various terrestrial surveying methods and a local benchmark network. This contribution provides details of the activities on Tristan da Cunha including the installations, the established benchmark network, the terrestrial surveys of the geodetic ties and the analysis of these measurements in order to geometrically link the GNSS and DORIS antennas to each other as well as to the tide gauges. [less ▲]

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See detailThe dual volume of quasi-Fuchsian manifolds and the Weil-Petersson distance
Mazzoli, Filippo UL

E-print/Working paper (2019)

Making use of the dual Bonahon-Schläfli formula, we prove that the dual volume of the convex core of a quasi-Fuchsian manifold M is bounded by an explicit constant, depending only on the topology of M ... [more ▼]

Making use of the dual Bonahon-Schläfli formula, we prove that the dual volume of the convex core of a quasi-Fuchsian manifold M is bounded by an explicit constant, depending only on the topology of M, times the Weil-Petersson distance between the hyperbolic structures on the upper and lower boundary components of the convex core of M. [less ▲]

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See detailDeep dive into Interledger: Understanding the Interledger ecosystem - Part 2
Trestioreanu, Lucian Andrei UL; Cassagnes, Cyril UL; State, Radu UL

Learning material (2019)

At the technical level, the goal of Interledger is to provide an architecture and a minimal set of protocols to enable interoperability for any value transfer system. The Interledger protocol is literally ... [more ▼]

At the technical level, the goal of Interledger is to provide an architecture and a minimal set of protocols to enable interoperability for any value transfer system. The Interledger protocol is literally a protocol for interledger payments. To understand how is it possible to achieve this goal, several aspects of the technology require a deeper analysis. For this reason, in our journey to become knowledgeable and active contributor we decided to create our own test-bed on our premises. By doing so, we noticed that some aspects are well documented but we found that others might need more attention and clarification. Despite a large community effort, the task to keep information on a fast evolving software ecosystem is tedious and not always the priority for such a project. Therefore, the purpose of this document is to guide, through several hands-on activities, community members who want to engage at different levels. The document consolidates all the relevant information from generating a simple payment to ultimately create a test-bed with the Interledger protocol suite between Ripple and other distributed ledger technology. [less ▲]

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See detailFacial perception and implicit prejudice: An eye-tracking study
Stogianni, Maria UL; Murdock, Elke UL

Poster (2019, July 09)

Racial bias can affect the way of processing visual stimuli that are targets of prejudice. Different levels of prejudice and the type of prejudice (implicit vs. explicit) were related to automatic and ... [more ▼]

Racial bias can affect the way of processing visual stimuli that are targets of prejudice. Different levels of prejudice and the type of prejudice (implicit vs. explicit) were related to automatic and controlled processes of visual exploration (Hansen Rakhshan, Ho, & Pannasch, 2015). The proposed study aims to extend these findings by including pictures of individuals that belong to different racial and ethnic groups (White, Asian, Black, Latino) and vary in prototypical characteristics. Images of the Chicago Face Database will be presented in an online study. Eye movements will be recorded during the presentation of visual stimuli. We will examine differences in exploratory looking behavior among natives in a western European country and individuals with migratory background. [less ▲]

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See detailWhy we do not care for statelessness as we care for asylum?
Sommarribas, Adolfo UL

Presentation (2019, July 07)

This presentation address the issue why statelessness is so marginalised in the migration discourse in the European Union even though is a growing phenomenon.

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See detailNation et migrations au Luxembourg
Scuto, Denis UL

Article for general public (2019)

This article focusses on the making of the nation and migrations in Luxembourg in 19th and 20th century, in a double perspective: Luxembourg nation as a product of transregional and transnational spaces ... [more ▼]

This article focusses on the making of the nation and migrations in Luxembourg in 19th and 20th century, in a double perspective: Luxembourg nation as a product of transregional and transnational spaces of migration and nation as the lens of observation of these migrations. [less ▲]

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See detailNamenskunde – Gender(re)konstruktionen in Autobiographien von Transpersonen
Artuso, Sandy Kathy UL

Scientific Conference (2019, July 05)

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See detailMaking Retail Banks Resolvable
Asimakopoulos, Ioannis UL

Presentation (2019, July 05)

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See detailInnovation et coopération dans les réseaux de données (années 1970-1990)
Schafer, Valerie UL

Presentation (2019, July 04)

A travers un parcours historique au coeur de 20 ans d'innovation dans les réseaux de données, depuis le développement d'Arpanet jusqu'à l'échec de l'OSI, en passant par Internet, XNS, Transpac ou encore ... [more ▼]

A travers un parcours historique au coeur de 20 ans d'innovation dans les réseaux de données, depuis le développement d'Arpanet jusqu'à l'échec de l'OSI, en passant par Internet, XNS, Transpac ou encore EIN, il s'agira d'interroger la place de la coopération technique mais aussi organisationnelle au sein des réseaux de données. Trop ou pas assez de coopération tue-t-il l'innovation? [less ▲]

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See detailInsights into protein structural, physicochemical, and functional consequences of missense variants in 1,330 disease-associated human genes 693259
Iqbal, Sumaiya; Jespersen, Jakob B.; Perez-Palma, Eduardo et al

E-print/Working paper (2019)

Inference of the structural and functional consequences of amino acid-altering missense variants is challenging and not yet scalable. Clinical and research applications of the colossal number of ... [more ▼]

Inference of the structural and functional consequences of amino acid-altering missense variants is challenging and not yet scalable. Clinical and research applications of the colossal number of identified missense variants is thus limited. Here we describe the aggregation and analysis of large-scale genomic variation and structural biology data for 1,330 disease-associated genes. Comparing the burden of 40 structural, physicochemical, and functional protein features of altered amino acids with 3-dimensional coordinates, we found 18 and 14 features that are associated with pathogenic and population missense variants, respectively. Separate analyses of variants from 24 protein functional classes revealed novel function-dependent vulnerable features. We then devised a quantitative spectrum, identifying variants with higher pathogenic variant-associated features. Finally, we developed a web resource (MISCAST; http://miscast.broadinstitute.org/) for interactive analysis of variants on linear and tertiary protein structures. The biological impact of missense variants available through the webtool will assist researchers in hypothesizing variant pathogenicity and disease trajectories. [less ▲]

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See detailRobotic Trajectory Tracking: Position- and Force-Control
Klecker, Sophie UL

Doctoral thesis (2019)

This thesis employs a bottom-up approach to develop robust and adaptive learning algorithms for trajectory tracking: position and torque control. In a first phase, the focus is put on the following of a ... [more ▼]

This thesis employs a bottom-up approach to develop robust and adaptive learning algorithms for trajectory tracking: position and torque control. In a first phase, the focus is put on the following of a freeform surface in a discontinuous manner. Next to resulting switching constraints, disturbances and uncertainties, the case of unknown robot models is addressed. In a second phase, once contact has been established between surface and end effector and the freeform path is followed, a desired force is applied. In order to react to changing circumstances, the manipulator needs to show the features of an intelligent agent, i.e. it needs to learn and adapt its behaviour based on a combination of a constant interaction with its environment and preprogramed goals or preferences. The robotic manipulator mimics the human behaviour based on bio-inspired algorithms. In this way it is taken advantage of the know-how and experience of human operators as their knowledge is translated in robot skills. A selection of promising concepts is explored, developed and combined to extend the application areas of robotic manipulators from monotonous, basic tasks in stiff environments to complex constrained processes. Conventional concepts (Sliding Mode Control, PID) are combined with bio-inspired learning (BELBIC, reinforcement based learning) for robust and adaptive control. Independence of robot parameters is guaranteed through approximated robot functions using a Neural Network with online update laws and model-free algorithms. The performance of the concepts is evaluated through simulations and experiments. In complex freeform trajectory tracking applications, excellent absolute mean position errors (<0.3 rad) are achieved. Position and torque control are combined in a parallel concept with minimized absolute mean torque errors (<0.1 Nm). [less ▲]

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See detailMapping Digital Urban History - Use Case Luxembourg
Kass, Steve UL; Pauli, Sebastian; Uhrmacher, Martin UL

Presentation (2019, July 04)

Since 2016, a research project of the University of Luxembourg (IHIST: Institute for History) in close collaboration with the city of Luxemburg is investigating research in the development of an ... [more ▼]

Since 2016, a research project of the University of Luxembourg (IHIST: Institute for History) in close collaboration with the city of Luxemburg is investigating research in the development of an interactive, dynamic web site, providing insights in the urban development since the beginning of the 19th century at single building level scale. The elaborated historic town Atlas represents a collection of maps and structures (e.g. building, fortress, streets) combined with explanatory texts, chronological tables and images, which all trace the history of the city and illustrate its stages of development. It represents a tool for additional new knowledge with which the historical process of change will be documented diachronically. The target groups are international urban history research and general public. [less ▲]

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See detailConsolidated democracy advantage: political instability and sovereign spreads in the EU
Glaurdic, Josip UL; Lesschaeve, Christophe UL; Vizek, Maruška

in Comparative European Politics (2019), Online first

We expose the way the market evaluates internal political risk and instability in democratic polities by analysing the determinants of sovereign spreads of EU member states over the course of the past two ... [more ▼]

We expose the way the market evaluates internal political risk and instability in democratic polities by analysing the determinants of sovereign spreads of EU member states over the course of the past two decades. Our analysis builds on the “democratic advantage” argument which suggests democracies enjoy preferential treatment on the international market of sovereign debt because of their better ability to make credible commitments. We suggest that, when it comes to the market’s evaluation of internal political instability and risk in democratic polities, there actually exists a “consolidated democracy advantage”. In times of political instability, older and more consolidated democracies pay less of a premium on their debt than their younger and less consolidated counterparts. In other words, the market indeed views the commitment of consolidated democracies with long track records of democratic competition and survival as something qualitatively diferent than the commitment of new democracies with short track records. [less ▲]

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See detailLes fonctions des parlements en démocratie aujourd’hui : quid de la représentation des minorités ?
Poirier, Philippe UL

Presentation (2019, July 02)

Les mécanismes des représentations parlementaires des minorités prévus dans les Etats membres de l’UE garantissent-ils les droits des citoyens qui les constituent et préservent-ils leurs chances d’exercer ... [more ▼]

Les mécanismes des représentations parlementaires des minorités prévus dans les Etats membres de l’UE garantissent-ils les droits des citoyens qui les constituent et préservent-ils leurs chances d’exercer les fonctions politiques primordiales ? [less ▲]

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See detailCreating better ground truth to further understand Android malware: A large scale mining approach based on antivirus labels and malicious artifacts
Hurier, Médéric UL

Doctoral thesis (2019)

Mobile applications are essential for interacting with technology and other people. With more than 2 billion devices deployed all over the world, Android offers a thriving ecosystem by making accessible ... [more ▼]

Mobile applications are essential for interacting with technology and other people. With more than 2 billion devices deployed all over the world, Android offers a thriving ecosystem by making accessible the work of thousands of developers on digital marketplaces such as Google Play. Nevertheless, the success of Android also exposes millions of users to malware authors who seek to siphon private information and hijack mobile devices for their benefits. To fight against the proliferation of Android malware, the security community embraced machine learning, a branch of artificial intelligence that powers a new generation of detection systems. Machine learning algorithms, however, require a substantial number of qualified samples to learn the classification rules enforced by security experts. Unfortunately, malware ground truths are notoriously hard to construct due to the inherent complexity of Android applications and the global lack of public information about malware. In a context where both information and human resources are limited, the security community is in demand for new approaches to aid practitioners to accurately define Android malware, automate classification decisions, and improve the comprehension of Android malware. This dissertation proposes three solutions to assist with the creation of malware ground truths. The first contribution is STASE, an analytical framework that qualifies the composition of malware ground truths. STASE reviews the information shared by antivirus products with nine metrics in order to support the reproducibility of research experiments and detect potential biases. This dissertation reports the results of STASE against three typical settings and suggests additional recommendations for designing experiments based on Android malware. The second contribution is EUPHONY, a heuristic system built to unify family clusters belonging to malware ground truths. EUPHONY exploits the co-occurrence of malware labels obtained from antivirus reports to study the relationship between Android applications and proposes a single family name per sample for the sake of facilitating malware experiments. This dissertation evaluates EUPHONY on well-known malware ground truths to assess the precision of our approach and produce a large dataset of malware tags for the research community. The third contribution is AP-GRAPH, a knowledge database for dissecting the characteristics of malware ground truths. AP-GRAPH leverages the results of EUPHONY and static analysis to index artifacts that are highly correlated with malware activities and recommend the inspection of the most suspicious components. This dissertation explores the set of artifacts retrieved by AP-GRAPH from popular malware families to track down their correlation and their evolution compared to other malware populations. [less ▲]

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See detailTranslanguaging Course for Teachers
Aleksic, Gabrijela UL; Bebic-Crestany, Dzoen

Scientific Conference (2019, July 01)

Amongst the many terms to describe the natural linguistic experiences of bilinguals, translanguaging is standing out as the socio-linguistic theory that consciously recognises a unitary linguistic ... [more ▼]

Amongst the many terms to describe the natural linguistic experiences of bilinguals, translanguaging is standing out as the socio-linguistic theory that consciously recognises a unitary linguistic repertoire of bilinguals. Translanguaging is used without regards to boundaries imposed by socio-politically constructed named languages and the unnatural differentiation of various forms of communication. The extensive research of many scholars, most notably by Li Wei and Ofelia García, confronts the social and educational suppression of minorities’ languages and cultures in schools. Their analyses and proposed solutions for social justice, therefore, serve as the theoretical and pedagogical basis of our research in Luxembourg’s multilingual education. The understanding that bilinguals translanguage naturally in conversation and for sense- and meaning-making purposes has also been shown in Luxembourg: 64% of four-year olds in Luxembourg do not speak Luxembourgish and translanguaging happens naturally. Research also shows that students of minority groups generally underperform at school. The implementation of translanguaging in Luxembourg’s multilingual education would therefore enable a better development of school and home language, metalinguistic awareness, linguistic tolerance, socio-emotional development and multilingual identity. To address the challenges of multilingual education in Luxembourg, we firstly offer a professional development (PD) course that aims to help teachers take a translanguaging stance, vital for its success. Secondly, we adapt the general translanguaging pedagogical methodology to incorporate home languages in teachers’ daily classroom activities. Our project has been supported by the Luxembourg National Research Fund* to deliver 8 sessions from the Translanguaging guide developed at the City University of New York. Given the local multilingual context, introducing translanguaging and adapting the guide is a challenge for us as researchers. We will use quantitative and qualitative methods to assess the success of the PD and better understand translanguaging as a theory, practice and pedagogy. [less ▲]

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See detailStandardising smart contracts: Automatically inferring ERC standards
Norvill, Robert UL; Fiz Pontiveros, Beltran UL; State, Radu UL et al

in 2019 IEEE International Conference on Blockchain and Cryptocurrency (2019)

Ethereum smart contracts have become common enough to warrant the need for standards to ensure ease of use. The most well known standard was created for the emerging token ecosystem and the exchanges ... [more ▼]

Ethereum smart contracts have become common enough to warrant the need for standards to ensure ease of use. The most well known standard was created for the emerging token ecosystem and the exchanges serving it: the ERC20 standard. In this work we use the function selectors present in Ethereum smart contract bytecode to define contract purpose. Contracts are clustered according to the selectors they have. A Reverse look-up from selectors to function names is used to label clusters. We use the function names in clusters to suggest candidates for ERC standardisation. [less ▲]

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