References of "Scientific congresses, symposiums and conference proceedings"
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See detailLe dialogue entre les juges en matière de protection des droits de l'homme
Pelin Raducu, Ioana UL

in Menetrey, Séverine; Hess, Burkhard (Eds.) Les dialogues des juges en Europe (in press)

Dans cet article, nous allons mettre en exergue quelques aspects des arrêts récents provenant de la Cour de justice de l’UE (Akerberg Frasson, Melloni, Kamberaj)qui démontrent l’émergence d’un standard ... [more ▼]

Dans cet article, nous allons mettre en exergue quelques aspects des arrêts récents provenant de la Cour de justice de l’UE (Akerberg Frasson, Melloni, Kamberaj)qui démontrent l’émergence d’un standard propre de l’UE en matière des droits de l’homme. Cette tendance de la C.J.U.E. contredira le prescrit normatif découlant du « dialogue des juges » d’interprétation conforme à la jurisprudence de la C.E.D.H. avant que l’adhésion de l’UE à la Convention E.D.H. ne soit formellement acquise. [less ▲]

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See detailA Methodology for Handling Data Movements by Anticipation: Position Paper
Bleuse, Raphaël UL; Lucarelli, Giorgio; Trystram, Denis

in Euro-Par 2018 Workshops (in press)

The enhanced capabilities of large scale parallel and distributed platforms produce a continuously increasing amount of data which have to be stored, exchanged and used by various tasks allocated on ... [more ▼]

The enhanced capabilities of large scale parallel and distributed platforms produce a continuously increasing amount of data which have to be stored, exchanged and used by various tasks allocated on different nodes of the system. The management of such a huge communication demand is crucial for reaching the best possible performance of the system. Meanwhile, we have to deal with more interferences as the trend is to use a single all-purpose interconnection network whatever the interconnect (tree-based hierarchies or topology-based heterarchies). There are two different types of communications, namely, the flows induced by data exchanges during the computations, and the flows related to Input/Output operations. We propose in this paper a general model for interference-aware scheduling, where explicit communications are replaced by external topological constraints. Specifically, the interferences of both communication types are reduced by adding geometric constraints on the allocation of tasks into machines. The proposed constraints reduce implicitly the data movements by restricting the set of possible allocations for each task. This methodology has been proved to be efficient in a recent study for a restricted interconnection network (a line/ring of processors which is an intermediate between a tree and higher dimensions grids/torus). The obtained results illustrated well the difficulty of the problem even on simple topologies, but also provided a pragmatic greedy solution, which was assessed to be efficient by simulations. We are currently extending this solution for more complex topologies. This work is a position paper which describes the methodology, it does not focus on the solving part. [less ▲]

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See detail« … Eripuit servus mihi vitam » - Représentations médiatiques de la violence et de la criminalité dans les provinces occidentales de l'Empire romain
Binsfeld, Andrea UL

in Amodio, Mara (Ed.) The imagery of violence in Roman society (I-VI cent.). Persistence, innovations and interrelations from the Roman to the Christian Empire (in press)

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See detailService Performance Pattern Analysis and Prediction of Commercially Available Cloud Providers
Wagle, Shyam Sharan UL; Guzek, Mateusz UL; Bouvry, Pascal UL

in Service Performance Pattern Analysis and Prediction of Commercially Available Cloud Providers (in press)

The knowledge of service performance of cloud providers is essential for cloud service users to choose the cloud services that meet their requirements. Instantaneous performance readings are accessible ... [more ▼]

The knowledge of service performance of cloud providers is essential for cloud service users to choose the cloud services that meet their requirements. Instantaneous performance readings are accessible, but prolonged observations provide more reliable information. However, due to technical complexities and costs of monitoring services, it may not be possible to access the service performance of cloud provider for longer time durations. The extended observation periods are also a necessity for prediction of future behavior of services. These predictions have very high value for decision making both for private and corporate cloud users, as the uncertainty about the future performance of purchased cloud services is an important risk factor. Predictions can be used by specialized entities, such as cloud service brokers (CSBs) to optimally recommend cloud services to the cloud users. In this paper, we address the challenge of prediction. To achieve this, the current service performance patterns of cloud providers are analyzed and future performance of cloud providers are predicted using to the observed service performance data. It is done using two automatic predicting approaches: ARIMA and ETS. Error measures of entire service performance prediction of cloud providers are evaluated against the actual performance of the cloud providers computed over a period of one month. Results obtained in the performance prediction show that the methodology is applicable for both short- term and long-term performance prediction. [less ▲]

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See detailTopologie culinaire au cinéma : le lieu commun du repas et ses déclinaison
Roelens, Nathalie UL

in Bibliothèque électronique Paris 8 (in press)

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See detailGenerating Automated and Online Test Oracles for Simulink Models with Continuous and Uncertain Behaviors
Menghi, Claudio UL; Nejati, Shiva UL; Gaaloul, Khouloud UL et al

in Proceedings of the 27th ACM Joint European Software Engineering Conference and Symposium on the Foundations of Software Engineering (ESEC/FSE ’19), (in press)

Test automation requires automated oracles to assess test outputs. For cyber physical systems (CPS), oracles, in addition to be automated, should ensure some key objectives: (i) they should check test ... [more ▼]

Test automation requires automated oracles to assess test outputs. For cyber physical systems (CPS), oracles, in addition to be automated, should ensure some key objectives: (i) they should check test outputs in an online manner to stop expensive test executions as soon as a failure is detected; (ii) they should handle time- and magnitude-continuous CPS behaviors; (iii) they should provide a quantitative degree of satisfaction or failure measure instead of binary pass/fail outputs; and (iv) they should be able to handle uncertainties due to CPS interactions with the environment. We propose an automated approach to translate CPS requirements specified in a logic-based language into test oracles specified in Simulink - a widely-used development and simulation language for CPS. Our approach achieves the objectives noted above through the identification of a fragment of Signal First Order logic (SFOL) to specify requirements, the definition of a quantitative semantics for this fragment and a sound translation of the fragment into Simulink. The results from applying our approach on 11 industrial case studies show that: (i) our requirements language can express all the 98 requirements of our case studies; (ii) the time and effort required by our approach are acceptable, showing potentials for the adoption of our work in practice, and (iii) for large models, our approach can dramatically reduce the test execution time compared to when test outputs are checked in an offline manner. [less ▲]

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See detailL’exposition d’objets ou de collections de « marque » : cobranding, réécriture, réénonciation
Schall, Céline UL

in Laval, Sylvie (Ed.) Marques muséales : un espace public revisité ? (in press)

Le cobranding est une pratique habituelle du secteur marchand. Mais lorsque deux musées réalisent ensemble une exposition, peut-on parler de cobranding muséal ? Quelles en seraient les spécificités  ... [more ▼]

Le cobranding est une pratique habituelle du secteur marchand. Mais lorsque deux musées réalisent ensemble une exposition, peut-on parler de cobranding muséal ? Quelles en seraient les spécificités ? Quels effets peut avoir cette démarche sur la communication ou sur l’exposition ? Notamment, le musée d’accueil s’approprie-t-il simplement l’imaginaire et les valeurs de la marque invitée par un phénomène de « transfert » ? Pour répondre à ces questions, nous étudions trois expositions qui reprennent des objets ou collections de musées dont la marque est internationalement reconnue. L’analyse sémiotique des images de marque du musée d’accueil et du musée invité ainsi que l’analyse sémiopragmatique des expositions montrent l’impact de la présence d’une grande marque internationale sur l’exposition et réciproquement, l’impact de l’exposition sur l’image de marque du musée d’accueil. Plus qu’un simple cobranding, c’est une réécriture impliquant une réénonciation du discours et des valeurs portés par les marques qui est proposée à travers ces expositions. Le processus aboutit à la création de nouveaux espaces symboliques et d’expositions réflexives, avec plusieurs niveaux de lecture. [less ▲]

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See detailCoercion-Resistant Voting in Linear Time via Fully Homomorphic Encryption: Towards a Quantum-Safe Scheme
Roenne, Peter UL; Atashpendar, Arash UL; Kristian, Gjøsteen et al

in Financial Cryptography and Data Security 2019. FC 2019: International Workshops, CIW, VOTING, and WTSC (in press)

We present an approach for performing the tallying work in the coercion-resistant JCJ voting protocol, introduced by Juels, Catalano, and Jakobsson, in linear time using fully homomorphic encryption (FHE ... [more ▼]

We present an approach for performing the tallying work in the coercion-resistant JCJ voting protocol, introduced by Juels, Catalano, and Jakobsson, in linear time using fully homomorphic encryption (FHE). The suggested enhancement also paves the path towards making JCJ quantum-resistant, while leaving the underlying structure of JCJ intact. The pairwise comparison-based approach of JCJ using plaintext equivalence tests leads to a quadratic blow-up in the number of votes, which makes the tallying process rather impractical in realistic settings with a large number of voters. We show how the removal of invalid votes can be done in linear time via a solution based on recent advances in various FHE primitives such as hashing, zero-knowledge proofs of correct decryption, verifiable shuffles and threshold FHE. We conclude by touching upon some of the advantages and challenges of such an approach, followed by a discussion of further security and post-quantum considerations. [less ▲]

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See detailDas Verhältnis zwischen Hochschule und Wissenschaft in Deutschland: Expansion – Produktion – Kooperation
Dusdal, Jennifer UL; Oberg, Achim; Powell, Justin J W UL

in DGS (Ed.) Komplexe Dynamiken globaler und lokaler Entwicklungen: Der Verhandlungsband des 39. Kongresses der Deutschen Gesellschaft für Soziologie vom 24.-28. September 2018 an der Georg-August-Universität Göttingen (in press)

Dieser Beitrag rekonstruiert den Einfluss der Hochschulentwicklung und der wissenschaftlichen Kapazitätsbildung auf die wissenschaftliche Wissensproduktion in Deutschland, einem der weltweit stärksten ... [more ▼]

Dieser Beitrag rekonstruiert den Einfluss der Hochschulentwicklung und der wissenschaftlichen Kapazitätsbildung auf die wissenschaftliche Wissensproduktion in Deutschland, einem der weltweit stärksten Produzenten wissenschaftlichen Wissen seit 1900. Folgende Forschungsfragen sollen beantwortet werden: Wie haben institutionalisierte Strukturen, und darin verschiedene Organisationsformen, die langfristige Entwicklung wissenschaftlicher Produktivität beeinflusst und verändert? In welchen organisationalen Netzwerken entwickelt sich aktuell die Wissenschaft weiter? Die Annäherung an den Forschungsgegenstand erfolgt auf der Makroebene anhand von Indikatoren zur Erfassung der globalen Expansion, Kooperation und Produktion der Wissenschaft. Vor dem Hintergrund dieses Untersuchungsrahmens wird dann auf der Mesoebene das Zusammenspiel von Organisationsformen in Deutschland mittels netzwerkanalytischer Verfahren betrachtet. Ziel des Beitrags ist, die Orte und institutionellen Settings wissenschaftlicher Produktion zu identifizieren und anhand ihrer Aufgaben und Ziele voneinander abzugrenzen sowie ihre Beziehungen zueinander herauszuarbeiten. Als theoretische Basis werden neo-institutionalistische Ansätze zur Untersuchung und Erklärung der Expansion des Hochschulwesens und der Wissenschaft und zur Analyse von organisationalen Netzwerken herangezogen. Grundlage der empirischen Analyse bilden Publikationen in peer-reviewed Zeitschriften als Kennzeichen wissenschaftlicher Produktion. [less ▲]

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See detailFeasibility of Stellar as a Blockchain-based Micropayment System
Khan, Nida UL; Ahmad, Tabrez; State, Radu UL

in Springer SmartBlock 2019 - 2nd International Conference on Smart Blockchain (in press)

The advent of Bitcoin was heralded as an innovation in the global monetary system, that could bring down transaction fees by circumventing the need for third parties and conduct transactions in real time ... [more ▼]

The advent of Bitcoin was heralded as an innovation in the global monetary system, that could bring down transaction fees by circumventing the need for third parties and conduct transactions in real time. The divisibility of a blockchain cryptocurrency to even fractions of a cent, caused microtransactions to become feasible to formerly non-existent denominations. These microtransactions have spurred the development of novel ways of monetizing online resources and hold the potential to aid in alleviation of poverty. The paper conducts a feasibility study on Stellar as a blockchain-based micropayment system. It highlights the computational and other issues that impedes its progress and utilizes a characterization model for micropayment systems to evaluate the efficacy of the Stellar platform. The paper conducts a comparison with the micropayment solutions from Bitcoin, Ethereum and PayPal. The paper analyzes a subset of transactions from the Stellar blockchain to aid in drawing a conclusion on the undertaken study and elaborates on the mitigation tools to enable fraud prevention in online monetary transactions. [less ▲]

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See detailUpdate Internationales und Europäisches Steuerrecht
Sinnig, Julia UL

in Taeger, Jürgen (Ed.) Tagungsband Herbstakademie 2019 (in press)

Im Juni 2019 stellte die Organisation für wirtschaftliche Zusammenarbeit und Entwicklung (OECD) das Arbeitsprogramm zur weiteren Ausarbeitung einer Anpassung des internationalen Ertragsteuerrechts an die ... [more ▼]

Im Juni 2019 stellte die Organisation für wirtschaftliche Zusammenarbeit und Entwicklung (OECD) das Arbeitsprogramm zur weiteren Ausarbeitung einer Anpassung des internationalen Ertragsteuerrechts an die neue wirtschaftliche Realität der digitalisierten Welt vor. Auf Ebene der Europäischen Union (EU) gilt die Verabschiedung der im März 2018 von der Europäischen Kommission vorgestellten Richtlinien-Vorschläge (RL-Vorschläge) zu einer Digitalsteuer und einer sog. signifikanten digitalen Präsenz, nach intensiver Diskussion im Rat, als unwahrscheinlich. Der Gerichtshof der Europäischen Union beschäftigt sich derzeit mit der unionsrechtlichen Vereinbarkeit nationaler Sonderabgaben, die umsatzbasiert erhoben werden. Dieser Beitrag bietet einen Überblick über wesentliche Entwicklungen im internationalen und europäischen Steuerrecht bzgl. der Besteuerung digitalisierter Unternehmen. Der Beitrag knüpft an den Vortrag von Prof. Dr. Jens M. Schmittmann und der Verfasserin anlässlich der Herbstakademie 2018 in Bochum, sowie dem Vortrag der Verfasserin anlässlich der Herbstakademie 2017 in Heidelberg an. [less ▲]

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See detailUsing Passive Data Collection Methods to Learn Complex Mobility Patterns: An Exploratory Analysis
Toader, Bogdan UL; Cantelmo, Guido UL; Popescu, Mioara et al

Scientific Conference (in press)

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See detailRigor or rhetoric: Public philosopher and public in dialogue
Burks, Deven UL

in Perspectives: international postgraduate journal of philosophy (in press), 9

Brian Leiter (2016) throws down two gauntlets to philosophers engaged in dialogue with the broader public. If, with the first, public philosophers recognize that they cannot offer substantive answers but ... [more ▼]

Brian Leiter (2016) throws down two gauntlets to philosophers engaged in dialogue with the broader public. If, with the first, public philosophers recognize that they cannot offer substantive answers but only sophisticated method, they nevertheless fail to realize that said method does not resonate with the very public whom they purport to help. For, with the second, that method does not engage the emotivist and tribalist cast of contemporary public discourse: emotivist because a person’s moral and political beliefs are a function of emotional attitudes or affective responses for which she adduces reasons post hoc; tribalist because the person tracks not the inferential relation between beliefs but her similarity with interlocutors. In order to understand the full extent of this critique, it is necessary, first, to parse strands of public philosophy, distinct discursive sites, and pictures of philosophical practice and, then, to probe the critique’s empirical groundedness and intended scope. These elements in place, it is then possible to sketch public philosophy reconceived along Leiter’s lines as equal part rigor and rhetoric. That sketch may be somewhat filled out through two tactics employed in Jeffrey Stout’s (2004, 2010) work. These form part of a toolkit for philosophical dialogue whereby philosophers get a discursive grip on non-discursive factors underlying public discourse and push back on Leiter's dilemma. [less ▲]

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See detailA New Perspective on the Luxembourgish Genitive
Döhmer, Caroline UL

in Germanic Genitives (in press)

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See detailLe quotidien d’un poilu de la première guerre mondiale sur Facebook : nouvelle forme de médiation, nouvelle expérience ?
Schall, Céline UL; Vilatte, Jean-Christophe

in Les mondes de la médiation culturelle (in press)

« En 2013, le Musée de la Grande Guerre du Pays de Meaux et l’agence de communication DDB ont élaboré une page Facebook d’un genre nouveau. Facebook 1914, le quotidien de la première guerre offre une ... [more ▼]

« En 2013, le Musée de la Grande Guerre du Pays de Meaux et l’agence de communication DDB ont élaboré une page Facebook d’un genre nouveau. Facebook 1914, le quotidien de la première guerre offre une forme de médiation a priori inédite pour un musée français. Elle présente l’histoire d’un personnage de fiction, Léon Vivien, qui raconte son quotidien lors de la première guerre mondiale, sur Facebook, comme si ce réseau social avait existé à cette époque. Cette contribution met en évidence certains des effets de sens de la page par une analyse sémiotique du dispositif et une analyse thématique de ses contenus. Nous questionnons ensuite cette « nouvelle » forme de médiation qui se dit « participante » et qui, en réalité, reste assez classique dans son contenu et sous-exploite le potentiel de Facebook. » [less ▲]

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See detailBack to the Moon: Legal Challenges for Future Lunar Exploration
Salmeri, Antonino UL

in Proceedings of the International Institute of Space Law (in press)

In the light of the recently renovated interest in returning humans to the Moon, this paper addresses the main legal challenges related, with the goal to show practical solutions under the current system ... [more ▼]

In the light of the recently renovated interest in returning humans to the Moon, this paper addresses the main legal challenges related, with the goal to show practical solutions under the current system of international space law. In order to do so, the paper first presents an overview of current lunar exploration programs, arguing that public and private missions raise different challenges and thus require specific models. Following, it accordingly assesses possible legal solutions for the regulation of these programs. On the one hand, States’ exploration programs may be governed by a revised version of the Intergovernmental Agreement already concluded for the International Space Station. On the other hand, private activities could be better organized relying on Articles VI-IX OST as integrated by a new UNGA Resolution, ad hoc bilateral agreements and specific provisions in national space legislations. Finally, the paper concludes underlining the importance of international cooperation as the key to ensure the peaceful use and exploration of outer space. [less ▲]

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See detailHistorical outline and chromatic properties of purpura rubra Tarentina and its potential identification with purple dye extracted from Bolinus brandaris
Meiers, Fabienne UL

in Enegren, Hedvig; Meo, Francesco (Eds.) Treasures from the Sea : Sea-Silk and Shell purple dye in antiquity. Proceedings from the International workshop, 26.-28.05. (in press)

This paper presents a historical overview of the importance of the red dye found in spiny dye-murices (Bolinus brandaris) and its production in Taranto, one of the most industrious Greek colonies founded ... [more ▼]

This paper presents a historical overview of the importance of the red dye found in spiny dye-murices (Bolinus brandaris) and its production in Taranto, one of the most industrious Greek colonies founded in southern Italy in the 8th century BC and renowned for its luxury products. Written evidence as well as numismatic and archaeological sources dating from the 5th century BC to the 5th century AD have been analysed in this context to identify purpura rubra Tarentina. In addition, the results of a series of dye experiments with hypobranchial glands from the same species are treated in order to detect chromatic properties and potential manufacturing processes for Tarentine Red. The methods for vatting the dye glands are discussed in relation to historical validity and chromatic outcome. To conclude, comparisons are drawn between the colour characteristics of Bolinus brandaris and Hexaplex trunculus (banded dye-murex), and the possibility of mixing both dyes is taken into consideration. The synthesis of historical and experimental approach finally shows that purpura rubra Tarentina can potentially be identified with purple dye extracted from Bolinus brandaris. [less ▲]

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See detailUsing crowd-sourced data to analyse the ongoing merger of [ɕ] and [ʃ] in Luxembourgish
Gilles, Peter UL

in Proceedings of the 19th International Congress of Phonetic Sciences. Melbourne, Australia (in press)

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See detailComputational Arithmetic of Modular Forms
Wiese, Gabor UL

in Buyukasik, Engin; Inam, Ilker (Eds.) Notes from the International Autumn School on Computational Number Theory: Izmir Institute of Technology 2017 (in press)

These course notes are about computing modular forms and some of their arithmetic properties. Their aim is to explain and prove the modular symbols algorithm in as elementary and as explicit terms as ... [more ▼]

These course notes are about computing modular forms and some of their arithmetic properties. Their aim is to explain and prove the modular symbols algorithm in as elementary and as explicit terms as possible, and to enable the devoted student to implement it over any ring (such that a sufficient linear algebra theory is available in the chosen computer algebra system). The chosen approach is based on group cohomology and along the way the needed tools from homological algebra are provided. [less ▲]

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See detailA Look into Privacy-Preserving Blockchains
Khan, Nida UL; Nassar, Mohamed

in IEEE BCA @AICCSA 2019 - Workshop on Blockchain and it's Applications (in press)

Blockchain is a revolutionary technology promising a new generation of decentralized, transparent and tamper-proof database systems. However, one of the main challenges of the emerging blockchain systems ... [more ▼]

Blockchain is a revolutionary technology promising a new generation of decentralized, transparent and tamper-proof database systems. However, one of the main challenges of the emerging blockchain systems remains to address data privacy. While in Bitcoin and similar e-cash systems, privacy was limited to anonymity and addressed by using cryptographic pseudonyms for identification and authentication of parties, the question of privacy has more breadth in systems maintaining actual data such as medical records or energy meters. In this paper, we look into recently proposed privacy-preserving blockchains, analyze their strengths and weaknesses, and highlight research questions requiring future investigation. We conclude that privacy-preserving blockchains are still in their infancy and more research is definitely needed in this area. [less ▲]

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See detailExternalisation de la politique migratoire et identité de l'Union européenne
Neframi, Eleftheria UL; Gatti, Mauro UL

in Benlolo, Myriam (Ed.) L'Union européenne et les migrations (in press)

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See detailDatenbank für Zweisprachige Historische Luxemburgische Bekanntmachungen
Gilles, Peter UL; Ziegler, Evelyn

in Wallmeier, Nadine; Tophinke, Doris (Eds.) Historische Stadtsprachenforschung (in press)

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See detailFundamental rights and constitutional identity(ies): limits or parameters of the EU constitutional governance?
Zinonos, Panagiotis UL

in European Governance and Sovereignty (in press)

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See detailQuantifying information flow in interactive systems
Mestel, David UL

in 2019 IEEE 32nd Computer Security Foundations Symposium (CSF) (in press)

We consider the problem of quantifying information flow in interactive systems, modelled as finite-state transducers in the style of Goguen and Meseguer. Our main result is that if the system is ... [more ▼]

We consider the problem of quantifying information flow in interactive systems, modelled as finite-state transducers in the style of Goguen and Meseguer. Our main result is that if the system is deterministic then the information flow is either logarithmic or linear, and there is a polynomial-time algorithm to distinguish the two cases and compute the rate of logarithmic flow. To achieve this we first extend the theory of information leakage through channels to the case of interactive systems, and establish a number of results which greatly simplify computation. We then show that for deterministic systems the information flow corresponds to the growth rate of antichains inside a certain regular language, a property called the width of the language. In a companion work we have shown that there is a dichotomy between polynomial and exponential antichain growth, and a polynomial time algorithm to distinguish the two cases and to compute the order of polynomial growth. We observe that these two cases correspond to logarithmic and linear information flow respectively. Finally, we formulate several attractive open problems, covering the cases of probabilistic systems, systems with more than two users and nondeterministic systems where the nondeterminism is assumed to be innocent rather than demonic. [less ▲]

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See detailJoint Scheduling and Precoding for Frame-Based Multigroup Multicasting in Satellite Communications
Bandi, Ashok UL; Shankar, Bhavani UL; Chatzinotas, Symeon UL et al

Scientific Conference (2019, December 09)

Recent satellite standards enforce the coding of multiple users’ data in a frame. This transmission strategy mimics the well-known physical layer multigroup multicasting (MGMC). However, typical beam ... [more ▼]

Recent satellite standards enforce the coding of multiple users’ data in a frame. This transmission strategy mimics the well-known physical layer multigroup multicasting (MGMC). However, typical beam coverage with a large number of users and limited frame length lead to the scheduling of only a few users. Moreover, in emerging aggressive frequency reuse systems, scheduling is coupled with precoding. This is addressed in this work, through the joint design of scheduling and precoding for frame-based MGMC satellite systems. This aim is formulated as the maximization of the sum-rate under per beam power constraint and minimum SINR requirement of scheduled users. Further, a framework is proposed to transform the non-smooth SR objective with integer scheduling and nonconvex SINR constraints as a difference-of-convex problem that facilitates the joint update of scheduling and precoding. Therein, an efficient convex-concave procedure based algorithm is proposed. Finally, the gains (up to 50%) obtained by the jointed design over state-of-the-art methods is shown through Monte-Carlo simulations. [less ▲]

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See detailSoftware Engineering for Dataset Augmentation using Generative Adversarial Networks
Jahic, Benjamin UL; Guelfi, Nicolas UL; Ries, Benoît UL

Scientific Conference (2019, October 19)

Software engineers require a large amount of data for building neural network-based software systems. The engineering of these data is often neglected, though, it is a critical and time-consuming activity ... [more ▼]

Software engineers require a large amount of data for building neural network-based software systems. The engineering of these data is often neglected, though, it is a critical and time-consuming activity. In this work, we present a novel software engineering approach for dataset augmentation using neural networks. We propose a rigorous process for generating synthetic data to improve the training of neural networks. Also, we demonstrate our approach to successfully improve the recognition of handwritten digits using conditional generative adversarial networks (cGAN). Finally, we shortly discuss selected important issues of our process, presenting related work and proposing some improvements. [less ▲]

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See detailMonitoring du système scolaire – Le modèle luxembourgeois (invited talk)
Fischbach, Antoine UL

Scientific Conference (2019, October 17)

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See detailP3LS : Plausible Deniability for Practical Privacy-Preserving Live Streaming
Decouchant, Jérémie UL; Boutet, Antoine; Yu, Jiangshan et al

Scientific Conference (2019, October)

Video consumption is one of the most popular Internet activities worldwide. The emergence of sharing videos directly recorded with smartphones raises important privacy concerns. In this paper we propose ... [more ▼]

Video consumption is one of the most popular Internet activities worldwide. The emergence of sharing videos directly recorded with smartphones raises important privacy concerns. In this paper we propose P3LS , the first practical privacy-preserving peer-to-peer live streaming system. To protect the privacy of its users, P3LS relies on k-anonymity when users subscribe to streams, and on plausible deniability for the dissemination of video streams. Specifically, plausible deniability during the dissemination phase ensures that an adversary is never able to distinguish a user’s stream of interest from the fake streams from a statistical analysis (i.e., using an analysis of variance). We exhaustively evaluate P3LS and show that adversaries are not able to identify the real stream of a user with very high confidence. Moreover, P3LS consumes 30% less bandwidth than the standard k-anonymity approach where nodes fully contribute to the dissemination of k streams. [less ▲]

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See detailWireless Multi-group Multicast Precoding with Selective RF Energy Harvesting
Gautam, Sumit UL; Lagunas, Eva UL; Chatzinotas, Symeon UL et al

Scientific Conference (2019, September 05)

We present a novel framework for multi-group multicast precoding in the presence of three types of wireless users which are distributed among various multicast groups. A multi-antenna transmitter conveys ... [more ▼]

We present a novel framework for multi-group multicast precoding in the presence of three types of wireless users which are distributed among various multicast groups. A multi-antenna transmitter conveys information and/or energy to the groups of corresponding receivers using more than one multicast streams. The information specific users have conventional receiver architectures to process data, energy harvesting users collect energy using the non-linear energy harvesting module and each of the joint information decoding and energy harvesting capable user is assumed to employ the separated architecture with disparate non-linear energy harvesting and conventional information decoding units. In this context, we formulate and analyze the problem of total transmit power minimization for optimal precoder design subjected to minimum signal-to-interference-and-noise ratio and harvested energy demands at the respective users under three different scenarios. This problem is solved via semi-definite relaxation and the advantages of employing separate information and energy precoders are shown over joint and per-user information and energy precoder designs. Simulation results illustrate the benefits of proposed framework under several operating conditions and parameter values. [less ▲]

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See detailValue-added models: To what extent do estimates of school effectiveness depend on the selection of covariates?
Levy, Jessica UL; Brunner, Martin; Keller, Ulrich UL et al

Scientific Conference (2019, September)

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See detailIntersymbol and Intercarrier Interference in OFDM Transmissions Through Highly Dispersive Channels
Alves Martins, Wallace UL; Cruz-Roldán, Fernando; Moonen, Marc et al

in Proc. of the 27th European Signal Processing Conference (EUSIPCO-2019) (2019, September)

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See detailTime-Deconvolutive CNMF for Multichannel Blind Source Separation
Dias, Thadeu; Biscainho, Luiz Wagner; Alves Martins, Wallace UL

in Anais do XXXVII Simpósio Brasileiro de Telecomunicações e Processamento de Sinais (SBrT 2019) (2019, September)

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See detailOn the Use of Vertex-Frequency Analysis for Anomaly Detection in Graph Signals
Lewenfus, Gabriela; Alves Martins, Wallace UL; Chatzinotas, Symeon UL et al

in Anais do XXXVII Simpósio Brasileiro de Telecomunicações e Processamento de Sinais (SBrT 2019) (2019, September)

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See detailFear and Euphoria
Lehnert, Thorsten UL

Scientific Conference (2019, August 28)

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See detailDimensional Comparison Effects on Facets of Subject-Specific Anxieties: A Nested Modelling Approach
Talic, Irma UL; Sparfeldt, Jörn; Möller, Jens et al

Scientific Conference (2019, August 16)

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See detailImplementing intelligence facets as predictors into the generalised I/E model
Hausen, Jennifer UL; Möller, Jens; Greiff, Samuel UL et al

Scientific Conference (2019, August 13)

The internal/external (I/E) frame of reference model postulates that achievement influences the formation of academic self-concept (ASC) via social and dimensional comparison processes. Its recent ... [more ▼]

The internal/external (I/E) frame of reference model postulates that achievement influences the formation of academic self-concept (ASC) via social and dimensional comparison processes. Its recent extension as the generalized I/E model allows further domains than math and verbal achievement. However, intelligence facets as an indicator of achievement have been neglected within the GI/E model framework. Therefore, the purpose of this research is to explore the influences of three intelligence facets (verbal, numerical, figural) on domain-specific ASCs beyond grades and achievement scores. We drew on N=382 German students to analyze verbal, numerical, and figural intelligence, German and math achievement, self-reported grades and ASCs in four domains. We performed a structural equation model using Mplus with grades, achievement scores and intelligence facets specified as predictors and domain-specific ASCs as criteria. Positive paths were found from math, physics, German and English grade to their corresponding self-concepts. A positive path was found between physics grade and math ASC while negative paths were found from English grade to math and physics ASC and from math grade to German, physics and English ASC. The path coefficients from math achievement to math ASC as well as to physics ASC were positive; German achievement was negatively related to math ASC. Lastly, numerical intelligence was positively related to physics ASC, and verbal intelligence was positively related to English ASC. Thus, intelligence, specifically numerical and verbal intelligence, seem to be valid predictors of domain-specific ACSs beyond grades and achievement test scores. [less ▲]

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See detailThe Long 19th Century of Music in Luxembourg. Music History, Sociology and Ethnology
Sagrillo, Damien UL

Scientific Conference (2019, August 09)

Music historiography is multifaceted. The historiography of music in Luxembourg is divided into various aspects. Firstly, it is part of regional music research in Europe and, as far as Luxembourg is ... [more ▼]

Music historiography is multifaceted. The historiography of music in Luxembourg is divided into various aspects. Firstly, it is part of regional music research in Europe and, as far as Luxembourg is concerned, national music research. A first point of view is music ethnology: citizens, nations have their songs and pass them on orally across national and linguistic borders and over generations. Folksongs originate from the music of the people, and patriotic music in Luxembourg is often music based on folksong styles. A further aspect of music in Luxembourg is that art music originated since the independence of the Grand Duchy in the 19th century. Sociological considerations deal with community music in Luxembourg. The starting point is a more liberal constitution, which for the first time offered citizens the right of assembly. Finally, my lecture will offer some insights of musical activities of people who left their homeland. [less ▲]

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See detailValue-added modeling in primary school: What covariates to include?
Levy, Jessica UL; Brunner, Martin; Keller, Ulrich UL et al

Scientific Conference (2019, August)

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See detailChapter 18: Luxembourg
Sinnig, Julia UL

in Maisto, Guglielmo (Ed.) New Trends in the Definition of Permanent Establishment (2019, August)

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See detailPresent-Day Land and Sea Level Changes around South Georgia Island: Results from Precise Levelling, GNSS, Tide Gauge and Satellite Altimetry Measurements
Teferle, Felix Norman UL; Dalziel, I W D; Hunegnaw, Addisu UL et al

Scientific Conference (2019, July 25)

South Georgia Island, the main land outcrop on the South Georgia microcontinent (SGM), is located approximately 1,400 km east of the Falkland Islands and approximately 1,400 km northeast of the ... [more ▼]

South Georgia Island, the main land outcrop on the South Georgia microcontinent (SGM), is located approximately 1,400 km east of the Falkland Islands and approximately 1,400 km northeast of the northernmost tip of the Antarctic peninsular. The SGM is believed to lie south of the North Scotia Ridge (NSR), which forms the boundary to the South America Plate, while to the south it is bordered by the Scotia Plate (SP). In its sub-Antarctic location, the island is largely covered by mountain glaciers which have been reported to be retreating due to climatic change. Furthermore, during past glaciation periods the island and its shelf area, stretching much of the SGM, have been ice covered as was revealed by scarring of the sub-oceanic topography. Together with ongoing tectonics along the NSR and recent seismicity at the SP boundary, these processes have the ability to produce significant uplift on local to regional scales. With its mid-ocean location in the Southern Atlantic Ocean South Georgia Island is in a key position for the oceanic and geodetic global monitoring networks. As these net-works suffer from a Hemisphere imbalance with the number of stations in the Northern Hemisphere outnumbering those in the Southern Hemisphere, operating these stations to the highest standards is of key scientific value. It is of particular interest to monitor the tide gauge (GLOSS ID 187) at King Edward Point (KEP) for vertical land movements to establish a continuous record of its datum within the Permanent Service for Mean Sea Level (PSMSL), which in turn makes it useful for long-term sea level studies and satellite altimetry calibrations. With the establishment of five GNSS stations on the islands by teams from Luxembourg, the UK and the USA during 2013 to 2015, and the scientific analysis of these data within a global network of stations, it has now become possible to study present-day vertical land movements and their impacts. Furthermore, together with four precise levelling campaigns of the KEP benchmark network in 2013, 2014 and two in 2017, it has also been possible to investigate the very local character of the vertical motions near KEP, i.e. the stability of the jetty upon which the tide gauge is mounted. In this study, we will present the still preliminary results from the GNSS and levelling measurements and will discuss their impact on the sea level record from the KEP tide gauge. Our measurements show that while South Georgia Island and the area around KEP are rising, the jetty and tide gauge are subsiding, leading to a lower magnitude of the observed sea level change than expected from satellite altimetry. In order to improve the agreement between these measurements both local and regional vertical land movements need to be monitored. [less ▲]

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See detailBracketing in student writing: its uses (and abuses)
Deroey, Katrien UL

Scientific Conference (2019, July 23)

This paper reports on the use of bracketed text in a large corpus of student writing. The function of bracketing has been neglected in academic writing research and coursebooks. Yet it is closely related ... [more ▼]

This paper reports on the use of bracketed text in a large corpus of student writing. The function of bracketing has been neglected in academic writing research and coursebooks. Yet it is closely related to important text construction issues such as information packaging, coherence, clarity, conciseness, intertextual framing and sourcing. With a view to informing academic writing description and instruction, we examined the relationship between bracketed text and its cotext in a wide variety of disciplines and assignment genres. The relationships are described using an adaptation of Halliday and Matthiessen’s (2014) logico-semantic framework of clausal relationships. To better understand and teach the use of this information packaging feature, we studied the relationship between bracketed text and its cotext in the British Academic Written English (BAWE) corpus of high-graded student assignments. Using Sketch Engine and corpus query language, we extracted a random sample of 2000 instances of bracketing in running text only. This subcorpus is composed of 500 instances from each of the four main disciplinary groupings (Arts and Humanities, Life Sciences, Physical Sciences, Social Sciences) and contains instances from most of the BAWE assignment genres. The concordances were imported into a database table in FileMaker Pro. This database programme facilitates coding by limiting choices depending on previous selections and thus guiding the coder through the analytical steps. For the analysis of the data, it offers flexibility for grouping records and aggregating results on different levels. The logico-semantic framework used in systemic functional linguistics to classify the relationships between clauses (Halliday & Matthiessen, 2014) served as our starting point to classify the relationships between bracketed text and cotext. This framework distinguishes two fundamental logico-semantic relationships: expansion, which ‘relates phenomena as being of the same order of experience’, and projection, which ‘relates phenomena of one order of experience (the processes of saying and thinking) to phenomena of a higher order (semiotic phenomena – what people say and think)’ (p. 443). The latter contains three subtypes: elaboration (‘one clause elaborates on the meaning of another by further specifying or describing it’) (p. 461), enhancement (‘one clause (or subcomplex) enhances the meaning of another by qualifying it) (p. 476) and extension (‘one clause extends the meaning of another by adding something new to it’) (p. 471). This framework was refined and expanded through several stages of interrating and discussion in order to reflect our findings. We first analysed a random sample of 1000 instances from the whole BAWE corpus. With the resulting adapted classificatory framework we next independently analysed a quarter of our subcorpus of 2000 concordances. This led to further refinement of the framework and classificatory criteria. Finally, we each analyzed a different set of concordances from the disciplinary groupings. Disciplinary informants were consulted where needed. Our analysis revealed four major logico-semantic relationships between the bracketed text and cotext: in addition to Halliday & Matthiessen’s (2014) projection (1) and expansion (elaboration (2), enhancement (3, 4), extension (5)), we identified bracketed text functioning as intratextual reference (6) and code (7). The few instances that could not be confidently classified were assigned to a ‘hard to classify’ category. (1) However the anticipated number of children per woman in Europe and the USA is still near or above two (Bongaarts, 1999), showing that many are still having children. (2) Many of these injures are healed fractures and breaks occurring around the torso (upper body). (3) It is dated to the reign of Nectanebo II (360-343 BC). (4) Acetanilide (4.78g, 35.4 mmol) was dissolved in cold, glacial acetic acid (25ml, 437.1 mmol) (5) Parmenides decision to include a cosmology that he has already (apparently) proved to be flawed is an interesting one to say the least. (6) This is called circular polarization (figure 5) and is the natural state of white light. (7) Stronger field ligands such as (PPh 3) and (NCS) increase the splitting. Projection was –perhaps not surprisingly- the most common relationship by far, although markedly less frequent in the Physical Sciences. Expansion was mainly achieved through elaboration, with restatements (2) and abbreviations predominating. Enhancement relationships were mostly temporal locations (3) or measurements (4). Extension was relatively rare (5). Intratextual references (6) took various forms, such as figures, appendices, equations, and line numbers for quoted text. Bracketed code was a marked feature of the Physical Sciences, occurring in formulae and enclosing symbols or abbreviations (7). Overall, students’ use of bracketed text appeared to reflect disciplinary conventions and reflected the genre goals of assignments by demonstrating knowledge, understanding and appropriate source use. Contrary to expectations, instances where the bracketed text seemed superfluous or adversely affected coherence were rare. We conclude by discussing what these findings mean for academic writing instruction. Reference Halliday, M. A. K., & Matthiessen, C. M. I. M. (2014). Halliday's introduction to functional grammar (4 ed.). Abingdon: Routledge. [less ▲]

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See detailAnalysis of Multi-path Onion Routing-based Anonymization Networks
de La Cadena Ramos, Augusto Wladimir UL; Kaiser, Daniel UL; Mitseva, Asya UL et al

in Data and Applications Security and Privacy XXXIII, 2019 (2019, July 15)

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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 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 detailWHY IS THE MARKET SKEWNESS-RETURN RELATIONSHIP NEGATIVE?
Lehnert, Thorsten UL

Scientific Conference (2019, July 09)

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

Scientific Conference (2019, July 05)

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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 detailTranslanguaging as a pedagogy, a practice or a strategy? Examples from a preschool and a primary school class in Luxembourg
Kirsch, Claudine UL; Degano, Sarah UL; Mortini, Simone UL

Scientific Conference (2019, July 01)

The concept of translanguaging has been continuously redefined in education, psycholinguistics and sociolinguistics, which has led to some loss of meaning. Regarding teacher translanguaging, studies show ... [more ▼]

The concept of translanguaging has been continuously redefined in education, psycholinguistics and sociolinguistics, which has led to some loss of meaning. Regarding teacher translanguaging, studies show that it has been used as a strategy to further comprehension and learning, and as a pedagogy. The latter recognizes the existence of multiple languages in class and leverages the students’ semiotic system to make meaning and learn (García et al. 2017). Translanguaging has thereby been understood either as a resource-oriented pedagogy that challenges traditional conceptualizations of bilingualism and language learning, or as a pedagogy that fights social inequalities. Most research studies adopt the first view (Poza, 2017). The present paper combines two longitudinal doctoral studies and investigates the ways in which a preschool and a primary school teacher use translanguaging in their classes in Luxembourg. Drawing on interviews and observations, the findings show that the preschool teacher implemented a translanguaging pedagogy. She planned for the use of several languages, opened translanguaging spaces, and systematically translanguaged where she believed it would support learning (Kirsch et al. submitted). By contrast, the primary school teacher used translanguaging as a pedagogical strategy. She used the curricular languages and only translanguaged to support particular students. These differences are explained by the curriculum and the preschool teacher’s attendance of a professional development course. The findings contribute to our understanding of possible ways of implementing translanguaging as a pedagogy. [less ▲]

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See detailTogether or Alone: The Price of Privacy in Collaborative Learinig
Pejo, Balazs UL; Tang, Qiang; Biczók, Gergely

in Proceedings on Privacy Enhancing Technologies (2019, July)

Machine learning algorithms have reached mainstream status and are widely deployed in many applications. The accuracy of such algorithms depends significantly on the size of the underlying training ... [more ▼]

Machine learning algorithms have reached mainstream status and are widely deployed in many applications. The accuracy of such algorithms depends significantly on the size of the underlying training dataset; in reality a small or medium sized organization often does not have the necessary data to train a reasonably accurate model. For such organizations, a realistic solution is to train their machine learning models based on their joint dataset (which is a union of the individual ones). Unfortunately, privacy concerns prevent them from straightforwardly doing so. While a number of privacy-preserving solutions exist for collaborating organizations to securely aggregate the parameters in the process of training the models, we are not aware of any work that provides a rational framework for the participants to precisely balance the privacy loss and accuracy gain in their collaboration. In this paper, by focusing on a two-player setting, we model the collaborative training process as a two-player game where each player aims to achieve higher accuracy while preserving the privacy of its own dataset. We introduce the notion of Price of Privacy, a novel approach for measuring the impact of privacy protection on the accuracy in the proposed framework. Furthermore, we develop a game-theoretical model for different player types, and then either find or prove the existence of a Nash Equilibrium with regard to the strength of privacy protection for each player. Using recommendation systems as our main use case, we demonstrate how two players can make practical use of the proposed theoretical framework, including setting up the parameters and approximating the non-trivial Nash Equilibrium. [less ▲]

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See detailA Model-driven Approach to Trace Checking of Temporal Properties with Aggregations
Boufaied, Chaima UL; Bianculli, Domenico UL; Briand, Lionel UL

in Journal of Object Technology (2019, July), 18(2), 151-21

The verification of complex software systems often requires to check quantitative properties that rely on aggregation operators (e.g., the average response time of a service). One way to ease the ... [more ▼]

The verification of complex software systems often requires to check quantitative properties that rely on aggregation operators (e.g., the average response time of a service). One way to ease the specification of these properties is to use property specification patterns, such as the ones for “service provisioning”, previously proposed in the literature. In this paper we focus on the problem of performing offline trace checking of temporal properties containing aggregation operators. We first present TemPsy-AG, an extension of TemPsy—an existing pattern-based language for the specification of temporal properties—to support service provisioning patterns that use aggregation operators. We then extend an existing model-driven procedure for trace checking, to verify properties expressed in TemPsy-AG. The trace checking procedure relies on the efficient mapping of temporal properties written in TemPsy-AG into OCL constraints on a meta-model of execution traces. We have implemented this procedure in the TemPsy-Check-AG tool and evaluated its performance: our approach scales linearly with respect to the length of the input trace and can deal with much larger traces than a state-of-the-art tool. [less ▲]

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See detailThe use of value-added models for the identification of schools that perform “against the odds”
Levy, Jessica UL; Brunner, Martin; Keller, Ulrich UL et al

Poster (2019, July)

Value-added (VA) modeling aims to quantify the effect of pedagogical actions on students’ achievement, independent of students’ backgrounds. VA modeling is primarily used for accountability and high ... [more ▼]

Value-added (VA) modeling aims to quantify the effect of pedagogical actions on students’ achievement, independent of students’ backgrounds. VA modeling is primarily used for accountability and high-stakes decisions. To date, there seems to be no consensus concerning the calculation of VA models. Our study aims to systematically analyze and compare different school VA models by using longitudinal large-scale data emerging from the Luxembourg School Monitoring Programme. Regarding the model covariates, first findings indicate the importance of language (i.e., language(s) spoken at home and prior language achievement) in VA models with either language or math achievement as a dependent variable, with the highest amount of explained variance in VA models for language. Concerning the congruence of different VA approaches, we found high correlations between school VA scores from the different models, but also high ranges between VA scores for single schools. We conclude that VA models should be used with caution and with awareness of the differences that may arise from methodological choices. Finally, we discuss the idea that VA models could be used for the identification of schools that perform “against the odds”, especially for those schools that have positive VA scores over several years. [less ▲]

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See detailCrowdsensed Data Learning-Driven Prediction of Local Businesses Attractiveness in Smart Cities
Capponi, Andrea UL; Vitello, Piergiorgio UL; Fiandrino, Claudio UL et al

in IEEE Symposium on Computers and Communications (ISCC), Barcelona, Spain, 2019 (2019, July)

Urban planning typically relies on experience-based solutions and traditional methodologies to face urbanization issues and investigate the complex dynamics of cities. Recently, novel data-driven ... [more ▼]

Urban planning typically relies on experience-based solutions and traditional methodologies to face urbanization issues and investigate the complex dynamics of cities. Recently, novel data-driven approaches in urban computing have emerged for researchers and companies. They aim to address historical urbanization issues by exploiting sensing data gathered by mobile devices under the so-called mobile crowdsensing (MCS) paradigm. This work shows how to exploit sensing data to improve traditionally experience-based approaches for urban decisions. In particular, we apply widely known Machine Learning (ML) techniques to achieve highly accurate results in predicting categories of local businesses (LBs) (e.g., bars, restaurants), and their attractiveness in terms of classes of temporal demands (e.g., nightlife, business hours). The performance evaluation is conducted in Luxembourg city and the city of Munich with publicly available crowdsensed datasets. The results highlight that our approach does not only achieve high accuracy, but it also unveils important hidden features of the interaction of citizens and LBs. [less ▲]

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See detailTBar: Revisiting Template-based Automated Program Repair
Liu, Kui UL; Koyuncu, Anil UL; Kim, Dongsun et al

in 28th ACM SIGSOFT International Symposium on Software Testing and Analysis (ISSTA) (2019, July)

We revisit the performance of template-based APR to build com-prehensive knowledge about the effectiveness of fix patterns, andto highlight the importance of complementary steps such as faultlocalization ... [more ▼]

We revisit the performance of template-based APR to build com-prehensive knowledge about the effectiveness of fix patterns, andto highlight the importance of complementary steps such as faultlocalization or donor code retrieval. To that end, we first investi-gate the literature to collect, summarize and label recurrently-usedfix patterns. Based on the investigation, we buildTBar, a straight-forward APR tool that systematically attempts to apply these fixpatterns to program bugs. We thoroughly evaluateTBaron the De-fects4J benchmark. In particular, we assess the actual qualitative andquantitative diversity of fix patterns, as well as their effectivenessin yielding plausible or correct patches. Eventually, we find that,assuming a perfect fault localization,TBarcorrectly/plausibly fixes74/101 bugs. Replicating a standard and practical pipeline of APRassessment, we demonstrate thatTBarcorrectly fixes 43 bugs fromDefects4J, an unprecedented performance in the literature (includ-ing all approaches, i.e., template-based, stochastic mutation-basedor synthesis-based APR). [less ▲]

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See detailA DEM approach for modeling biomass fast pyrolysis in a double auger reactor
Qi, Fenglei UL

Scientific Conference (2019, July)

Thermochemical conversion of biomass via fast pyrolysis process is a promising way to produce renewable fuels and chemicals. In this paper, an extended discrete element method (DEM) is developed to ... [more ▼]

Thermochemical conversion of biomass via fast pyrolysis process is a promising way to produce renewable fuels and chemicals. In this paper, an extended discrete element method (DEM) is developed to predict the biomass fast pyrolysis process in a double auger reactor, which is described as a reacting granular flow. The thermodynamic state of each particle is properly predicted with an addition of a heat transfer model and a reaction model on top of the traditional DEM method. The results suggest that the predictions of the thermochemical decomposition kinetics of biomass components are consistent with the experimental observations. The results also indicate that the fast pyrolysis in the reactor is controlled by the heat transfer process. Any operating condition variation in favor of enhancing heat transfer is beneficial to the fast pyrolysis process and vice versa. [less ▲]

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See detailExpansion nach Belgien als Verwaltungstätigkeit: der Kölner Beamte Franz Thedieck im NS
Brüll, Christoph UL

Scientific Conference (2019, June 28)

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See detailN point Virasoro algebras are multi-point Krichever Novikov type algebras
Schlichenmaier, Martin UL

Scientific Conference (2019, June 28)

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See detailForced migrants in Luxembourg: an LE approach to linguistic integration
Kalocsanyiova, Erika UL

Scientific Conference (2019, June 28)

This paper outlines the core contributions that a linguistic ethnography (LE) approach can make to forced migration and integration research. LE provides multiple tools for capturing the complexity and ... [more ▼]

This paper outlines the core contributions that a linguistic ethnography (LE) approach can make to forced migration and integration research. LE provides multiple tools for capturing the complexity and transient character of the real social environments in which forced migrants integrate. After summarising the main arguments of the literature which examines the language–displacement nexus, this contribution moves on to discuss the nature and focus of the proposed approach. It then turns to specific examples from a two-year LE research project that addressed the impact of multilingualism on forced migrants’ trajectories in Luxembourg. [less ▲]

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See detailOn the single-peakedness property
Devillet, Jimmy UL

Scientific Conference (2019, June 28)

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See detailOpening Remarks / Chair / Program Chair
Schafer, Valerie UL

Scientific Conference (2019, June 27)

Decoding Europe. Technological Pasts in the Digital Age. The conference will study – in an interdisciplinary way – the impact of digitisation on historical developments and the consequences of the digital ... [more ▼]

Decoding Europe. Technological Pasts in the Digital Age. The conference will study – in an interdisciplinary way – the impact of digitisation on historical developments and the consequences of the digital turn on the writing and shaping of European history. The Tensions of Europe (ToE) conference is organised biennially. ToE is an interdisciplinary community of scholars who study the shaping of Europe by paying attention to the role of technology and material culture. It welcomes fruitful interaction between historians of technology and scholars who study technology from all other fields of the humanities and the social sciences. [less ▲]

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See detailLaser polishing of Aluminum and Polyamide for dissimilar laser welded assemblies
Amne Elahi, Mahdi UL; Koch, Marcus; Plapper, Peter UL

Scientific Conference (2019, June 27)

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See detailHistory of networks: evolution, issues, challenges
Schafer, Valerie UL

Scientific Conference (2019, June 26)

This conference described and analyzed the recent evolutions in the field of the history of Internet and of the Web, underlining new trends and challenges.

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See detailLaser overlap joining from copper to aluminum and analysis of failure zone
Mathivanan, Karthik UL; Plapper, Peter UL

Scientific Conference (2019, June 26)

Joining of copper and aluminum sheets are very crucial for battery application. When joining from copper sheet, keyhole mode of welding is essential to overcome the reflectivity and melting threshold of ... [more ▼]

Joining of copper and aluminum sheets are very crucial for battery application. When joining from copper sheet, keyhole mode of welding is essential to overcome the reflectivity and melting threshold of copper. However, in dissimilar material interaction the resulting intermetallic (IMC) phases are brittle, which result in reduced performance.This paper analyses the joint with laser beam irradiated from the copper side (Cu on top). The idea is to distribute the intermetallic compounds inside the joint to obtain a ductile behavior. The zones of failure and the distribution of the intermetallic phase is studied. The microstructural analysis of the fusion zone and mechanical strength of the joint are presented. [less ▲]

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See detailRécits visuels de la Grande Guerre au Luxembourg : cent ans de manuels d'histoire
Camarda, Sandra UL; Scuto, Denis UL

Scientific Conference (2019, June 26)

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See detailWhispering Botnet Command and Control Instructions
Steichen, Mathis UL; Ferreira Torres, Christof UL; Fiz Pontiveros, Beltran UL et al

in 2nd Crypto Valley Conference on Blockchain Technology, Zug 24-26 June 2019 (2019, June 25)

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See detailBenefits, challenges, social learning and controversies around Local Food Systems
Reckinger, Rachel UL; Nemes, Gusztav; Lajos, Veronika

Scientific Conference (2019, June 25)

Objectives: Our WG touches upon three main elements among the themes of the conference: (1) innovation, (2) social justice and (3) knowledge production. Innovative local food systems and alternative food ... [more ▼]

Objectives: Our WG touches upon three main elements among the themes of the conference: (1) innovation, (2) social justice and (3) knowledge production. Innovative local food systems and alternative food networks, approached from a collaborative and participatory angle, bring about a cultural shift by associating prosumers through a renewed form of trust, reciprocity and community, thus reinforcing social and ecological justice. At the same time, such heterodox actors in the transition to more sustainable food systems create new forms of knowledge, that are contested, co-constructed and potentially conflictual – along with enabling or disabling policymaking and, often, in dialogue with research. Our main objective is in this topic to start the process of creating an edited special issue of a peer reviewed journal (Sociologia Ruralis, Studies of Agricultural Economics or similar) should raise from this WG. We invite researchers working in the area of (local) food systems, alternative food networks, short food supply chains and related topics (rural tourism, community supported agriculture, etc.). We consider both the benefits and possible conflicts/problems in the connected socio-economic, cultural and environmental processes and welcome theoretical papers and case studies, too. Topic: By welcoming case studies from all geographical areas, in a comparative manner, this Working Group’s aim is to address different understandings and dynamics happening within and around different types of Local Food Systems (LFS). Alternative food networks, local food systems and short food supply chains have long been viewed as a sustainable, green way of raising the value added and creating opportunities for sur/re-vival of rural economy and society. They induce many benefits in terms of environmental impact, cultural exemplification, ethical entrepreneurship, social justice or rural development. Conceptually, LFS can be understood as ‘local food for local people’, as for example in the Slow Food or the community supported agriculture (CSA) movements. They are then associated with low food miles, environmental protection (Jones 2002), enhanced social networks and revitalised local communities (Fenstra 1997). From a local economic development perspective, in particular when LFS produce high quality products, they can equally be considered as ‘local food for non-local people’, either transported to urban centres, or attracting flows of tourists into rural areas. Here LFS can still enhance local businesses, economic and rural development, yet social and environmental benefits (Guthman 2004) of such foodstuffs, marketed with the added value of environmental and social responsibility, are more difficult to trace. Therefore, besides benefits, we would also like to analyse potential dissonances, that the distinction between local or extra-local target groups help to identify – for instance: • established, certified organic producers might criticize non-certified yet organically producing CSAs as fragmenting an already minority market or showing a lack of solidarity by not contributing to organic labels; • when LFS end up producing high quality, expensive products, a dynamic of social exclusion might occur, favoring the wealthy; • enhanced local production, tourism, and visitor pressure can cause social, economic, and environmental degradation, multiplier effects do not always occur to build more businesses and sustain social and economic capital; • innovative alternative food networks tend to struggle with territorial competition over land and resources, but if they rely on external investments, they might additionally be confronted – more insidiously – with the risk of co-option by neoliberal corporate agendas. We welcome analyses focusing on negotiations and struggles among actors in a multifaceted foodscape, where some block and some enhance transitions. Viewing the relationships, interconnectedness and agency of niche innovations, local and non-local appropriations as well regime hegemonies opens up the theoretical perspective of contested knowledge claims. We look for questions and answers including: • How are dynamics of “knowing and growing food in a contested arena” (Goodman, DuPuis, Goodman, 2014) negotiated – sometimes in a mutually enhancing and locally beneficial way, sometimes in more conflictual ways? • What are the local and extra-local stakeholders’ (producers, intermediaries, customers, tourists) different and often conflicting interests and responsibilities in LFS? • What can we learn from the tensions and local problems of LFS in order to support relevant policies to solve current controversies within the sector? • How can rural sociologists use their knowledge and influence to support local rural stakeholders of LFS? [less ▲]

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See detailCharacterizations and enumerations of classes of quasitrivial n-ary semigroups
Devillet, Jimmy UL; Couceiro, Miguel

Scientific Conference (2019, June 23)

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See detailOverestimation of physical activity among young people: Does age and gender play a role?
Eckelt, Melanie UL; Hutmacher, Djenna UL; Steffgen, Georges UL et al

Scientific Conference (2019, June 22)

Background and purpose: Due to the continuous decrease of physical activity (PA) of people in industrialized countries (Kohl et al., 2012), PA behavior and its psychological foundations has become a key ... [more ▼]

Background and purpose: Due to the continuous decrease of physical activity (PA) of people in industrialized countries (Kohl et al., 2012), PA behavior and its psychological foundations has become a key issue in health-related research. Studies show that most people tend to overesti-mate their habitual PA (Skender et al., 2016), however, there is very little research on the role of demographic variables in this respect. Therefore, the aim of this study was to examine whether age and/or gender affect the (over)estimation of PA among children and adolescents. Methods: Data of 75 students (38 girls and 37 boys, 10 to 18 years) of various primary and sec-ondary schools were randomly included in the study. Habitual PA was assessed through an online self-report questionnaire (Schmidt et al., 2017) as well as by wearing an accelerometer (Acti-Graph GT3X-BT) over seven consecutive days. A multiple regression analysis was used to ana-lyze the impact of age and gender on the accuracy of PA estimation. Results: The students reported being active for at least 60 minutes on average on 4,0 ± 2,1 days per week, whereas the accelerometer data verify only 1,8 ± 1,6 days per week. Thus, a majority of 76% of the children and adolescents overestimated and 9% underestimated their PA. Almost 15% were correct in their PA estimation. However, results of the regression analysis indicate neither an effect of age ( = .003, p > .1) nor of gender ( = -.070, p > .1). Conclusions: Overestimation of PA is common not only among adults but also among children and adolescents. However, this misperception appears to be independent of age and gender, at least in the age group considered here. Future studies should examine further demographic and psychological variables in order to explain why most of the people significantly overestimate their habitual PA. [less ▲]

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See detail"Are you a boy or girl?" Who are the non-responders
Heinz, Andreas UL; Catunda, Carolina UL; van Duin, Claire UL et al

Scientific Conference (2019, June 20)

Background: In many studies, participants who do not state their gender are excluded from the analysis. This may be appropriate if they do not answer the questionnaire seriously. However, some ... [more ▼]

Background: In many studies, participants who do not state their gender are excluded from the analysis. This may be appropriate if they do not answer the questionnaire seriously. However, some participants may have understandable reasons for not reporting their gender, e.g. questioning their gender identity. Objective: How many students and which students do not answer the question on gender? Methods: HBSC 2018 raw data from Ireland, Luxembourg, Belgium and France are compared. To explore the reasons for non-response, we divided the participants into 3 groups: 1. Responders answered both sociodemographic questions (age and gender) 2. age non-responders did not answer the question on age. 3. Gender non-responders answered the question on age, but not the one on gender. Results: Between 0.8% (Ireland) and 1.2% (Luxembourg) of participants did not report their gender. About half of them did not answer the age question either. However, the other half belong to the group of gender non-responders and this group is disadvantaged compared to responders: they report lower life satisfaction, lower self-rated health, more health complaints, less peer support and their WHO-5 Well-being score is lower. Not answering the question on gender is rare. If the participants answered the question on age, but not the question on gender, then the variable gender is missing not at random. Implication: The question arises whether the group of gender non-responders should be included in the analysis and whether the question on gender should be asked differently in the future. [less ▲]

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See detailBridging the Gap between Requirements Modeling and Behavior-driven Development
Alferez, Mauricio UL; Pastore, Fabrizio UL; Sabetzadeh, Mehrdad UL et al

Scientific Conference (2019, June 20)

Acceptance criteria (AC) are implementation agnostic conditions that a system must meet to be consistent with its requirements and be accepted by its stakeholders. Each acceptance criterion is typically ... [more ▼]

Acceptance criteria (AC) are implementation agnostic conditions that a system must meet to be consistent with its requirements and be accepted by its stakeholders. Each acceptance criterion is typically expressed as a natural-language statement with a clear pass or fail outcome. Writing AC is a tedious and error-prone activity, especially when the requirements specifications evolve and there are different analysts and testing teams involved. Analysts and testers must iterate multiple times to ensure that AC are understandable and feasible, and accurately address the most important requirements and workflows of the system being developed. In many cases, analysts express requirements through models, along with natural language, typically in some variant of the UML. AC must then be derived by developers and testers from such models. In this paper, we bridge the gap between requirements models and AC by providing a UML-based modeling methodology and an automated solution to generate AC. We target AC in the form of Behavioral Specifications in the context of Behavioral-Driven Development (BDD), a widely used agile practice in many application domains. More specially we target the well-known Gherkin language to express AC, which then can be used to generate executable test cases. We evaluate our modeling methodology and AC generation solution through an industrial case study in the financial domain. Our results suggest that (1) our methodology is feasible to apply in practice, and (2) the additional modeling effort required by our methodology is outweighed by the benefits the methodology brings in terms of automated and systematic AC generation and improved model precision. [less ▲]

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See detail„What’s a normal weight?“ – Weight assessment standards in Origin- and Receiving Country and Immigrant Adolescents’ Weight-Status Self-Assessment
Kern, Matthias Robert UL; Heinz, Andreas UL; Stevens, Gonneke et al

Scientific Conference (2019, June 19)

Background: Many young people struggle with correctly assessing their weight-status, often leaving over- or underweight to go unnoticed thereby preventing adequate intervention. The prevalence of weight ... [more ▼]

Background: Many young people struggle with correctly assessing their weight-status, often leaving over- or underweight to go unnoticed thereby preventing adequate intervention. The prevalence of weight-status misperception differs considerably cross-nationally, indicating that individual weight-status assessment is informed by culturally transmitted standards of evaluation. For adolescents with a migration background, this brings up the problem of multiple frames of reference, as their perception of weight-status may be influenced by different cultural standards. Objective: We investigate the extent to which the assessment of one's own weight-status is based on standards of the heritage country or the receiving country. Methods: Data are retrieved from the 2014 Health Behaviour in School-Aged Children study. The cross-national design of the study enabled us to aggregate weight-evaluation standards for 41 countries and subsequently identify a large sample of 8132 immigrant adolescents in 23 receiving countries from 41 heritage countries. The influence of heritage- and receiving country standards of evaluation was assessed using cross-classified multilevel models. Results: Descriptive analyses reveal considerable differences in weight-evaluation standards between the countries. We find evidence of a significant influence of both heritage- and receiving culture standards of evaluation, with a stronger impact of receiving culture standards. Stratified analyses reveal a stronger influence of heritage culture standards among first- than among second-generation immigrants, and a stronger influence of receiving culture standards among second- than among first-generation immigrants. Conclusions: The results corroborate our expectations regarding the persistency of cultural standards and help to understand inter-ethnic differences in weight-status assessment. [less ▲]

Detailed reference viewed: 34 (4 UL)
See detailPhase field fracture model for viscoplastic materials in large deformations
Kabore, Brice Wendlassida UL; Loew, Pascal Juergen UL; Peters, Bernhard UL

Scientific Conference (2019, June 13)

Phase-field modeling approach to material fracture and damage has received a growing interest among researchers. It has proven to be an effective way to address crack related discontinuities in continuum ... [more ▼]

Phase-field modeling approach to material fracture and damage has received a growing interest among researchers. It has proven to be an effective way to address crack related discontinuities in continuum mechanics. Also, it solves the problem related to tracking the fracture surface by simply representing the fracture phase with a continuous field variable. Recently, phase-field fracture models have been extended to finite deformations, crack nucleation and applied to complex material behaviors such as plasticity and viscoplasticity. In this contribution we describe a viscoplastic model coupled with a phase-field dynamic fracture model in a large strain formulation. The model include damage, history, rate and temperature dependent behavior. A finite element implementation is presented in a staggered time integration. Moreover, we address the crack closure and crack surfaces interpenetration taking into account tension-compression strength asymmetry. Performance of the model on dynamic crack propagation are presented. [less ▲]

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See detailUser Experience challenges for designing and evaluating Computer-Based Assessments for children
Lehnert, Florence Kristin UL

in IDC '19 Proceedings of the 18th ACM International Conference on Interaction Design and Children (2019, June 12)

Computer-Based Assessment (CBA), i.e., the use of computers instead of paper & pencil for testing purposes is now increasingly used, both in education and in the workforce. Along with this trend, several ... [more ▼]

Computer-Based Assessment (CBA), i.e., the use of computers instead of paper & pencil for testing purposes is now increasingly used, both in education and in the workforce. Along with this trend, several issues regarding the usage of computers in assessment can be raised. With respect to CBA, test validity and acceptance appear at stake during interacting with a complex assessment system. For instance, individual differences in computer literacy (i.e. ability to handle technology) might cause different outcomes that are not related to the problem-solving task. Prior investigation has shown that there is a scarcity of research on the User Experience (UX) in the context of CBA, also due to a focus on adult users. This doctoral thesis aims to adapt and develop new evaluation methods from the Human-Computer Interaction (HCI) field, applied in the context of CBA. The contributions will result in the development of best practices guidelines for both research and practitioners by adopting design and evaluation methods drawn from the field of Child-computer Interaction (CCI). [less ▲]

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See detailAn enhanced interface model for friction fatigue problems of axially loaded piles
Kullolli, Borana; Baeßler, Matthias; Cuéllar, Pablo et al

in Proceedings of the ASME 2019 38th, International Conference on Ocean, Offshore and Arctic Engineering, Glasgow 9-14 June 2019 (2019, June 09)

The shaft bearing capacity often plays a dominant role for the overall structural behaviour of axially loaded piles in offshore deep foundations. Under cyclic loading, a narrow zone of soil at the pile ... [more ▼]

The shaft bearing capacity often plays a dominant role for the overall structural behaviour of axially loaded piles in offshore deep foundations. Under cyclic loading, a narrow zone of soil at the pile-soil interface is subject to cyclic shearing solicitations. Thereby, the soil may densify and lead to a decrease of confining stress around the pile due to micro-phenomena such as particle crushing, migration and rearrangement. This reduction of radial stress has a direct impact on the shaft capacity, potentially leading in extreme cases to pile failure. An adequate interface model is needed in order to model this behaviour numerically. Different authors have proposed models that take typical interface phenomena in account such as densification, grain breakage, normal pressure effect and roughness. However, as the models become more complex, a great number of material parameters need to be defined and calibrated. This paper proposes the adoption and transformation of an existing soil bulk model (Pastor- Zienkiewicz) into an interface model. To calibrate the new interface model, the results of an experimental campaign with the ring shear device under cyclic loading conditions are here presented. The constitutive model shows a good capability to reproduce typical features of sand behaviour such as cyclic compaction and dilatancy, which in saturated partially-drained conditions may lead to liquefaction and cyclic mobility phenomena. [less ▲]

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See detailLe rôle du Pôle Européen de Développement entre le Luxembourg, la Belgique et la France dans l’émergence d’un territoire transfrontalier
Pigeron-Piroth, Isabelle UL; Belkacem, Rachid

Scientific Conference (2019, June 07)

Au pays des trois frontières (Athus en Belgique, Longwy en France, Pétange au Luxembourg), ces territoires ont connu une histoire commune du déclin industriel. Dans le cadre de programme européen de ... [more ▼]

Au pays des trois frontières (Athus en Belgique, Longwy en France, Pétange au Luxembourg), ces territoires ont connu une histoire commune du déclin industriel. Dans le cadre de programme européen de reconversion de ces espaces, l'implantation d'un pôle européen de développement au milieu des années 1980, a constitué le principal instrument de reconversion de ces territoires. Après 20 ans de fonctionnement, le PED a produit différents effets sur la structuration de ces territoires transfrontaliers : une diversification inégale de part et d'autre des frontières du tissu productif local, une accélération des mobilités transfrontalières avec le développement du travail frontalier, un accroissement de la population locale avec de nouveaux profils sociologiques qui marque de nouvelle logique de mobilité résidentielle, ... Si le PED a permis d'amortir fortement la crise du système productif local, il a néanmoins contribué à diversifier les trajectoires de développement territorial de part et d'autre des frontières. On voit se dessiner au pays des trois frontières, un nouveau modèle de segmentation territoriale traduisant la juxtaposition de zones d'activités dynamiques d'un côté de la frontière avec des territoires à vocation résidentielle de l'autre côté de la frontière. [less ▲]

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See detailNetworks and Governance of Local Food Systems. The case of Food Policy Councils
Reckinger, Rachel UL

Scientific Conference (2019, June 06)

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See detailA forcing fictitious domain/immersed boundary method for super-quadric shape of particulate flow simulation of cementitious material
Wu, Mingqiu UL; Peters, Bernhard UL; Dressler, Inka

Scientific Conference (2019, June 05)

Fictitious domain/immersed boundary method (FD/IBM) has recently been used for particulate flows and complex fluid-solid interaction problems. The advantage of FD/IBM over the body- fitted method is that ... [more ▼]

Fictitious domain/immersed boundary method (FD/IBM) has recently been used for particulate flows and complex fluid-solid interaction problems. The advantage of FD/IBM over the body- fitted method is that it substantially simplifies grid generation for immersed geometries, and it is easier to handle moving boundary situations. FD/IBM even allows the use of a stationary and non- deformation background mesh, as well as it reduces the cost of computation by avoiding generation of a body-fitted mesh for each time step. In this work, we develop a new platform to directly simulate super-quadric (SQ) particles in fluid based on a forcing fictitious domain method. Specifically, a super-quadric particle function is used to represent particle with varying shapes and sizes as encountered for concrete and mortar. The immersion of particles in fluid is handled by imposing a rigidity solid body motion in the particle domain, as well as adding a forcing term to the Navier-stokes equation by integral of pressure gradient and particle related velocity over the whole particle domain. Particle shapes are given by changing the super-quadric parameters of SQ equation. Particle motions, which occur during pumping of cementitious material, can be calculated and tracked by solving Newton’s equations of motions using the extended discrete element method (XDEM)[4] while the data of fluid flow properties are obtained by solving the Navier-Stokes equations which govern the fluid phase. Hence, a particle interface resolving solver is developed by coupling XDEM and IBM. We validate our solver by performing flow around particles and free falling of a particle in the channel at different parameters in 2D and 3D. The final objective of this work is to develop a particle-resolved direct numerical simulation platform to predict highly packed fluids with different shapes of particles and over a wide range of particle sizes. [less ▲]

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See detailMagnetic neutron scattering studies on Nd-Fe-B magnets (Keynote Lecture)
Michels, Andreas UL

Scientific Conference (2019, June 05)

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See detailInvestment fund performance validation - Vine copulae estimation using a minimum spanning tree
Petijean, Simon; Schiltz, Jang UL

Scientific Conference (2019, June 03)

Catching the dependencies between financial time series is a complex exer- cise with a lot of challenges, both of theoretical and practical nature. We develop a metho- dology to model portfolio dynamics ... [more ▼]

Catching the dependencies between financial time series is a complex exer- cise with a lot of challenges, both of theoretical and practical nature. We develop a metho- dology to model portfolio dynamics using the minimum spanning tree methods combined with econometric models which solves a good part of these challenges. We use a tracking error that is equivalent to the Euclidean distance, to cluster the closest market indices. Financial risk is difficult to manage, because risk is evolving constantly and depends on very different factors like volatility, liquidity, asset class etc. To capture this evolution we develop a recursive portfolio validation method that reveals the true nature of the evolution of the risk structure of financial portfolios. We investigate several portfolio strategies to understand the dynamics behind the holdings. We thus validate the results of our portfolio analysis. We use a vine copula construction, which allows us to separate the marginal estimation from the dependence estimation and calibrate the underlying dynamics very precisely. The minimum spanning tree method helps us to create a robust tree foundation to support the entire vine structure. Starting from a portfolio analysis, we are thus able to validate the portfolio valuation over a specific period of time. [less ▲]

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See detailŽidé, identita, domov a rodinné dědictví
Bronec, Jakub UL

Scientific Conference (2019, June 01)

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See detailDesigning collaborative scenarios on tangible tabletop interfaces - insights from the implementation of paper prototypes in the context of a multidisciplinary design workshop
Sunnen, Patrick UL; Arend, Béatrice UL; Heuser, Svenja UL et al

in Proceedings of the 17th European Conference on Computer-Supported Cooperative Work: The International Venue on Practice-centred Computing and the Design of Cooperation Technologies - Exploratory Papers, Reports of the European Society for Socially Embedded Technologies (2019, June)

Within the context of the research project ORBIT (Overcoming Breakdowns in Teams with Interactive Tabletops), we design and study a joint problem-solving activity at an interactive tabletop, that gives ... [more ▼]

Within the context of the research project ORBIT (Overcoming Breakdowns in Teams with Interactive Tabletops), we design and study a joint problem-solving activity at an interactive tabletop, that gives participants the opportunity to develop their collaboration methods. To gain design insights for the development of a scenario soliciting participants to collaborate, we set up a multidisciplinary design workshop. During the latter, we explored and discussed three different collaborative scenarios, implemented as paper prototypes. In this paper, we report on first results gained from an exploratory analysis of the video data that was recorded in the context of this workshop. [less ▲]

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See detailMagnetic Guinier Law
Malyeyev, Artem UL; Michels, Andreas UL

Poster (2019, June)

We introduce the Guinier law for the case of magnetic SANS and provide an analysis of experimental data on a Nd-Fe-B-based nanocomposite and on a rare-earth-free MnBi permanent magnet. The robustness of ... [more ▼]

We introduce the Guinier law for the case of magnetic SANS and provide an analysis of experimental data on a Nd-Fe-B-based nanocomposite and on a rare-earth-free MnBi permanent magnet. The robustness of this novel approach is discussed and the quantities derived are analyzed in the framework of the existing research literature. [less ▲]

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See detailResilience and innovative work behaviours of entrepreneurs: The moderating role of gender
Geraudel, Mickaël UL; Cesinger, Beate; Gundolf, Katherine et al

Scientific Conference (2019, June)

Detailed reference viewed: 46 (0 UL)
See detailEine Krise der Öffentlichkeit : Protest, Populismus, "Neue Medien"
Kohns, Oliver UL

Scientific Conference (2019, June)

Detailed reference viewed: 37 (1 UL)
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See detailCraving for violence: The role of Dark Personality traits in violent video game preference
Melzer, André UL

Scientific Conference (2019, June)

Background: Violent and antisocial video games are popular, but little is known why players are drawn to these kinds of games. This present research tested whether there is a connection between player ... [more ▼]

Background: Violent and antisocial video games are popular, but little is known why players are drawn to these kinds of games. This present research tested whether there is a connection between player preferences for violent games and characteristics of so called “dark” personality traits. Method: Relying on a user-centered approach, three online studies (N=662) examined the role of “dark” personality traits together with a novel violent game preference short scale. Results: Study 1 and 2 indicated strong correlations between trait aggression and players’ interest in explicit depictions of blood and gore and games that provide experiences of domination and antisocial behavior. In Study 3, the new scale was tested together with participants’ trait aggression, trait empathy, and the Dark Triad traits of psychopathy, Machiavellianism, and narcissism. Games featuring violence and the possibility of antisocial behavior were found to meet the needs of players who lack empathy and show callous, impulsive, and exploitive (but not narcissistic) attributes. Conclusions: Findings of individual motivators for game violence significantly extend the literature that is predominantly focusing on the effects of playing these games. Apparently, game preferences and playing habits fulfill individual needs that are at least partly determined by particular, i.e. “dark”, personality characteristics. [less ▲]

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See detailA real time hybrid controller for regulating bus operations and reducing stops at signals
Laskaris, Georgios UL; Seredynski, Marcin; Viti, Francesco UL

Scientific Conference (2019, June)

We propose a hybrid controller which consists of holding and a Driver Advisory System (DAS). It combines the objectives of seeking the regularization of operation and the reduction of stop and go actions ... [more ▼]

We propose a hybrid controller which consists of holding and a Driver Advisory System (DAS). It combines the objectives of seeking the regularization of operation and the reduction of stop and go actions at signalized intersections. A simple headway based holding criterion is applied at stops to define the time needed to maintain even spaced headways between buses and additionally a speed recommendation is given to traverse during green indication at the downstream signalized intersection. The controller is tested using simulation for a bus line of the city of Luxembourg, Luxembourg and compared to a benchmark scenario, the single application of bus holding, two advisory systems and different levels of transit signal priority. Results show that there are additional benefits compared to traditional holding in terms of regularity while similar performance to strong transit signal priority is achieved in terms of time spent at traffic lights. [less ▲]

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See detailGrenze als multiple (Sozio-)Materialität
Wille, Christian UL

Scientific Conference (2019, June)

Detailed reference viewed: 44 (3 UL)
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See detailLeveraging GIS Data and Topological Information to Infer Trip Chaining Behaviour at Macroscopic Level
Carrese, Filippo; Fusco, Gaetano; Cantelmo, Guido et al

Scientific Conference (2019, June)

One of the open challenges in transport modelling is to estimate within-day demand flows that reflect the complexity of individual activity-travel behaviour. While disaggregate (Activity-Based) demand ... [more ▼]

One of the open challenges in transport modelling is to estimate within-day demand flows that reflect the complexity of individual activity-travel behaviour. While disaggregate (Activity-Based) demand models can recreate realistic daily mobility patterns at an individual level, they usually require an accurate knowledge of individual user behaviour (i.e. via travel surveys), which is not always available. As a result, practitioners often turn to aggregate demand models, that have the advantage of being less demanding in terms of data but typically under represent the demand for secondary activities. In this work, we take research on within-day demand modelling one step forward by proposing a framework that combines traditional methodologies with heterogeneous data sources in order to explicitly represent trip chaining at an aggregated level. We show that the combination of web-based crowd sensed data, network data and behavioural constraints allows to capture complex spatial and temporal correlations between demand patterns. The methodology is applied on the classical Gravity model to show how to incorporate within-day dynamics. Yet, any alternative demand model can be adopted. In our case, Generation and Attraction are used to estimate the systematic demand, that is enriched of information about individual activity patterns, and then a novel definition of impedance function based on Hagestraand ellipse theory plays a central role in spatially distributing locations of trips using geographic relationships and constraints deriving from space-time behaviour. A case study for Luxembourg City has been presented to show the potential of the methodology: the choice of using data from a different spatial context to account for the temporal dimension has been validated through comparisons with official statistics. The results of simulating a workplace relocation show the advantages of this new approach in representing demand related to secondary activities. [less ▲]

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See detailSupply characteristics and membership choice in round-trip and free-floating carsharing systems
Cisterna, Carolina UL; Giorgione, Giulio UL; Cipriani, Ernesto et al

Scientific Conference (2019, June)

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