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See detailConservazione e ricezione dei documenti pontifici in Italia settentrionale: il caso del monastero cistercense di Chiaravalle Milanese (secoli XII-XVI)
Salemme, Timothy UL

in Salemme, Timothy; Renault, Jean-Baptiste (Eds.) Conservation et réception des documents pontificaux par les Ordres religieux (XIe-XVe siècles). Actes du colloque international. Nancy, 12-13 décembre 2013 (in press)

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See detailUpdate Internationales und Europäisches Steuerrecht
Sinnig, Julia UL

in Taeger, Jürgen (Ed.) Tagungsband DSRI-Herbstakademie 2020 (in press)

Im Berichtszeitraum dieses Updates rief die OECD zu einem zweiten Öffentlichkeitsbetei-ligungsverfahren auf und erarbeitete einen präziseren Lösungsansatz zur Besteuerung digitalisierter Geschäftsmodelle ... [more ▼]

Im Berichtszeitraum dieses Updates rief die OECD zu einem zweiten Öffentlichkeitsbetei-ligungsverfahren auf und erarbeitete einen präziseren Lösungsansatz zur Besteuerung digitalisierter Geschäftsmodelle, der in einer Veröffentlichung im Januar 2020 vorgestellt wurde. Auf Ebene der Europäischen Union gab es im Berichtszeitraum keine Weiterent-wicklung der Richtlinienvorschläge zu einer Digitalsteuer und dem Konzept der „signifi-kanten digitalen Präsenz“. Der EuGH urteilte am 3. März 2020 in Hinblick auf die unions-rechtliche Vereinbarkeit zweier ungarischer Umsatzsteuern. Dieses Urteil erlaubt erste Rückschlüsse bezüglich der Europarechtskonformität umsatzbasierter Steuern, wie bspw. auch im Berichtszeitraum eingeführte Digitalsteuern einzelner Mitgliedstaaten. Dieser Beitrag knüpft an die Vorträge von Prof. Dr. Jens M. Schmittmann und der Verfasserin anlässlich der Herbstakademien 2018 in Bochum und 2019 in Oldenburg, sowie dem Vortrag der Verfasserin anlässlich der Herbstakademie 2017 in Heidelberg an. [less ▲]

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See detailHybrid Analog-Digital Precoding Design for Satellite Systems
Arora, Aakash UL; Tsinos, Christos UL; Shankar, Bhavani UL et al

in Proc. 37th International Communications Satellite Systems Conference (ICSSC'19) (in press)

The work investigates the feasibility of massive MIMO in SatCom. Towards this, the necessary channel models, system parameters and scenarios are identified and a basic simulator developed. The work then ... [more ▼]

The work investigates the feasibility of massive MIMO in SatCom. Towards this, the necessary channel models, system parameters and scenarios are identified and a basic simulator developed. The work then considers an efficient implementation of the massive MIMO transmission through the use of hybrid analog/digital precoder. Efficient algorithmic solutions are proposed for the partially connected precoder architecture which enables efficiency in power/ hardware complexity and its performance evaluated. [less ▲]

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See detailProcess analysis in thermal process engineering with high-performance computing using the example of grate firing
Peters, Bernhard UL; Rousset, Alban UL; Besseron, Xavier UL et al

in 12th European Conference on Industrial Furnaces and Boilers (in press)

Biomass as a renewable energy source continues to grow in popularity to reduce fossil fuel consumption for environmental and economic benefits. In the present contribution, the combustion chamber of a 16 ... [more ▼]

Biomass as a renewable energy source continues to grow in popularity to reduce fossil fuel consumption for environmental and economic benefits. In the present contribution, the combustion chamber of a 16 MW geothermal steam super-heater, which is part of the Enel Green Power "Cornia 2" power plant, is being investigated with high-performance computing methods. For this purpose, the extended discrete element method (XDEM) developed at the University of Luxembourg is used in a high-performance computing environment, which includes both the moving wooden bed and the combustion chamber above it. The XDEM simulation platform is based on a hybrid four-way coupling between the Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD). In this approach, particles are treated as discrete elements that are coupled by heat, mass, and momentum transfer to the surrounding gas as a continuous phase. For individual wood particles, besides the equations of motion, the differential conservation equations for mass, heat, and momentum are solved, which describe the thermodynamic state during thermal conversion. The consistency of the numerical results with the actual system performance is discussed in this paper to determine the potentials and limitations of the approach. [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 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 detailLes archevêques de Milan face aux premières expériences seigneuriales: stratégies et positionnements (milieu XIIIe-début XIVe s.)
Salemme, Timothy UL

in Barralis, Christine (Ed.) L’évêque face à son métier. Actes du colloque international, Metz. 15-17 novembre 2017 (in press)

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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 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 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 detailLa Charte dans l'action extérieure de l'Union européenne
Neframi, Eleftheria UL

in Iliopoulou Penot, Anastasia; Xenou, Lamprini (Eds.) La Charte des droits fondamentaux de l'UE (in press)

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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 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 detailGoal-Directed Decision Procedures for Input/Output Logics
Steen, Alexander UL

in Marra, Alessandra; Liu, Fenrong; Portner, Paul (Eds.) et al Deontic Logic and Normative Systems: 15th International Conference (DEON2020/2021, Munich) (in press)

Input/Output (I/O) logics address the abstract study of conditional norms. Here, norms are represented as pairs of formulas instead of statements that themselves carry truth-values. I/O logics have been ... [more ▼]

Input/Output (I/O) logics address the abstract study of conditional norms. Here, norms are represented as pairs of formulas instead of statements that themselves carry truth-values. I/O logics have been studied thoroughly in the past, including further applications and refinements. In this paper, a class of automated reasoning procedures is presented that, given a set of norms and a concrete situation, decide whether a specific state of affairs is obligatory according to the output operations of I/O logics. The procedures are parametric in the underlying logical formalism and can be instantiated with different classical objects logics, such as propositional logic or first-order logic. The procedures are shown to be correct, and a proof-of-concept implementation for propositional I/O logics is surveyed. [less ▲]

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See detailWhich Properties has an Icon? A Critical Discussion on Evaluation Methods for Standardised Data Protection Iconography
Rossi, Arianna UL; Lenzini, Gabriele UL

in Proceedings of the 8th Workshop on Socio-Technical Aspects in Security and Trust (STAST) (in press)

Following GDPR's Article12.7's proposal to use standardized icons to inform data subject in "an easily visible, intelligible and clearly legible manner," several icon sets have been developed. In this ... [more ▼]

Following GDPR's Article12.7's proposal to use standardized icons to inform data subject in "an easily visible, intelligible and clearly legible manner," several icon sets have been developed. In this paper, we firstly critically review some of those proposals. We then examine the properties that icons and icon sets should arguably fulfill according to Art.12's transparency provisions. Lastly, we discuss metrics and evaluation procedures to measure compliance with the Article. [less ▲]

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See detailDiscrete-Phase Sequence Design with Stopband and PSL Constraints for Cognitive Radar
Alaeekerahroodi, Mohammad UL; Kumar, Sumit UL; Mysore Rama Rao, Bhavani Shankar UL et al

in Proceedings of EuRAD 2020 (in press)

We present the design of discrete-phase sequences considering simultaneously the peak sidelobe level (PSL) and avoiding reserved frequency bands which are occupied by narrowband interferers or ... [more ▼]

We present the design of discrete-phase sequences considering simultaneously the peak sidelobe level (PSL) and avoiding reserved frequency bands which are occupied by narrowband interferers or communications. We use the coordinate descent framework and propose an algorithm to design discrete-phase sequences with spectral power suppressed in arbitrary bands and with low auto-correlation sidelobes in terms of PSL. Our proposed algorithm exploits fast Fourier transform and is, therefore, computationally efficient. The over-the-air experiments using implementation on software-defined radio show reasonable agreement with numerical simulations and feasibility for field-deployment [less ▲]

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See detailBlockchain Governance: An Overview and Prediction of Optimal Strategies Using Nash Equilibrium
Khan, Nida UL; Ahmad, Tabrez; Patel, Anass et al

in 3rd AUE International Research Conference (in press)

Blockchain governance is a subject of ongoing research and an interdisciplinary view of blockchain governance is vital to aid in further research for establishing a formal governance framework for this ... [more ▼]

Blockchain governance is a subject of ongoing research and an interdisciplinary view of blockchain governance is vital to aid in further research for establishing a formal governance framework for this nascent technology. In this paper, the position of blockchain governance within the hierarchy of Institutional governance is discussed. Blockchain governance is analyzed from the perspective of IT governance using Nash equilibrium to predict the outcome of different governance decisions. A payoff matrix for blockchain governance is created and simulation of different strategy profiles is accomplished for computation of all Nash equilibria. We also create payoff matrices for different kinds of blockchain governance, which were used to propose novel mathematical formulae usable to predict the best governance strategy that minimizes the occurrence of a hard fork as well as predicts the behavior of the majority during protocol updates. [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 detailDon't Trust Me, Test Me: 100% Code Coverage for a 3rd-party Android App
Pilgun, Aleksandr UL

in Pilgun, Aleksandr (Ed.) Don't Trust Me, Test Me: 100% Code Coverage for a 3rd-party Android App (in press)

The incompleteness of 3rd-party app testing is an accepted fact in Software Engineering. This issue makes it impossible to verify the app functionality and to confirm its safety to the end-user. To solve ... [more ▼]

The incompleteness of 3rd-party app testing is an accepted fact in Software Engineering. This issue makes it impossible to verify the app functionality and to confirm its safety to the end-user. To solve this problem, enterprises developed strict policies. A company, willing to use modern apps, may perform an expensive security analysis, rely on trust or forbid the app. These strategies may lead companies to high direct and indirect spending with no guarantee of safety. In this work, we present a novel approach, called Dynamic Binary Shrinking, that allows a user to review app functionality and leave only tested code. The shrunk app produces 100% instruction coverage on observed behaviors and in this way guarantees the absence of unexplored, and therefore, potentially malicious code. On our running examples, we demonstrate that apps use less than 20% of the codebase. We developed an approach and the ACVCut tool to shrink Android apps towards the executed code. Repository — http://github.com/pilgun/acvcut. [less ▲]

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See detailThe legacy of coal mining – a view on examples in Belgium and France
Helfer, Malte UL

in Deutsches Bergbau-Museum Bochum (Ed.) Boom – Crisis – Heritage. King Coal and Energy Revolutions after 1945; proceedings of the international conference March 14th-16th 2018, Technische Hochschule Georg Agricola, Bochum (in press)

Following the end of coalmining in Belgium (1992) and France (2004), the year 2018 marks the end of hard coal mining in Germany as well. This contribution looks at the legacy of coalmining of Germany’s ... [more ▼]

Following the end of coalmining in Belgium (1992) and France (2004), the year 2018 marks the end of hard coal mining in Germany as well. This contribution looks at the legacy of coalmining of Germany’s French-speaking neighbours and presents the most important remaining coal mining heritage sites as well as some extraordinary converted sites in France and the Belgian province Wallonia. [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 detailWidths of regular and context-free languages
Mestel, David UL

in 39th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2019) (in press)

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See detailAn MDE Method for Improving Deep Learning Dataset Requiements Engineering using Alloy and UML
Ries, Benoit UL; Guelfi, Nicolas UL; Jahic, Benjamin UL

in Proceedings of the 9th International Conference on Model-Driven Engineering and Software Development (2021, February)

Since the emergence of deep learning (DL) a decade ago, only few software engineering development methods have been defined for systems based on this machine learning approach. Moreover, rare are the DL ... [more ▼]

Since the emergence of deep learning (DL) a decade ago, only few software engineering development methods have been defined for systems based on this machine learning approach. Moreover, rare are the DL approaches addressing specifically requirements engineering. In this paper, we define a model-driven engineering (MDE) method based on traditional requirements engineering to improve datasets requirements engineering. Our MDE method is composed of a process supported by tools to aid customers and analysts in eliciting, specifying and validating dataset structural requirements for DL-based systems. Our model driven engineering approach uses the UML semi-formal modeling language for the analysis of datasets structural requirements, and the Alloy formal language for the requirements model execution based on our informal translational semantics. The model executions results are then presented to the customer for improving the dataset validation activity. Our approach aims at validating DL-based dataset structural requirements by modeling and instantiating their datatypes. We illustrate our approach with a case study on the requirements engineering of the structure of a dataset for classification of five-segments digits images. [less ▲]

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See detailVertex Feature Encoding and Hierarchical Temporal Modeling in a Spatio-Temporal Graph Convolutional Network for Action Recognition
Papadopoulos, Konstantinos UL; Ghorbel, Enjie UL; Aouada, Djamila UL et al

in International Conference on Pattern Recognition, Milan 10-15 January 2021 (2021, January)

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See detailKant's supposed realism about things-in-themselves
Heidemann, Dietmar UL

in Serck-Hanssen, Camila (Ed.) Proceedings of the 13th International Kant Congress ‘The Court of Reason’ (Oslo, 6-9 August 2019) (2021)

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See detailConcise UC Zero-Knowledge Proofs for Oblivious Updatable Databases
Camenisch, Jan; Dubovitskaya, Maria; Rial, Alfredo UL

in 2021 34th IEEE Computer Security Foundations Symposium (2021)

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See detailStochastic-Geometry-Based Interference Modeling in Automotive Radars Using Matérn Hard-Core Process
Mishra, K. V.; R., B. Shankar M.; Ottersten, Björn UL

in 2020 IEEE Radar Conference (RadarConf20), Stochastic-Geometry-Based Interference Modeling in Automotive Radars Using Matérn Hard-Core Process (2020, December 04)

As the use of radars in autonomous driving systems becomes more prevalent, these systems are increasingly susceptible to mutual interference. In this paper, we employ stochastic geometry to model the ... [more ▼]

As the use of radars in autonomous driving systems becomes more prevalent, these systems are increasingly susceptible to mutual interference. In this paper, we employ stochastic geometry to model the automotive radar interference in realistic traffic scenarios and then derive trade-offs between the radar design parameters and detection probability. Prior works model the locations of radars in the lane as a homogeneous Poisson point process (PPP). However, the PPP models assume all nodes to be independent, do not account for the lengths of vehicles, and ignore spatial mutual exclusion. In order to provide a more realistic interference effect, we adopt the Matérn hardcore process (MHCP) instead of PPP, in which two vehicles are not closer than an exclusion radius from one another. We show that the MHCP model leads to more practical design trade-offs for adapting the radar parameters than the conventional PPP model. [less ▲]

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See detailAR4OER: A Semantic Platform for Open Educational Augmented Reality Resources
Grevisse, Christian UL; Martins Gomes, Carina; Rothkugel, Steffen UL

in Proceedings of the 2020 IEEE International Symposium on Multimedia (2020, December)

Tablet computers are gaining in presence in modern-day classrooms, enabling the use of a variety of apps for purposes such as note-taking or assessment. Augmented Reality (AR) experiences in the classroom ... [more ▼]

Tablet computers are gaining in presence in modern-day classrooms, enabling the use of a variety of apps for purposes such as note-taking or assessment. Augmented Reality (AR) experiences in the classroom, made possible by current hardware, permit new ways of interaction and visualization, as well as increase student motivation and engagement. They also overcome the need for potentially expensive hardware required for experiments in certain scientific domains. The movement of Open Educational Resources (OER) has enabled the sharing of heterogeneous learning resources. Their retrieval can be improved by enriching their metadata using Semantic Web technologies. In this paper, we present AR4OER, a semantic platform for heterogeneous AR experiences provided as OER. We showcase four AR scenarios from different school subjects. These scenarios can be integrated through a lose coupling in third-party apps. Apart from describing how this integration works, we demonstrate how a note-taking app can benefit from these scenarios. [less ▲]

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See detailLow-light image enhancement of permanently shadowed lunar regions with physics-based machine learning
Moseley, Ben; Bikel, Valentin; Lopez-Francos, Ignacio et al

in Low-light image enhancement of permanently shadowed lunar regions with physics-based machine learning (2020, December)

Finding water(-ice) on the Moon is key to enabling a sustainable human presence on the Moon and beyond. There is evidence that water-ice is abundant in and around the Moon’s Permanently Shadowed Regions ... [more ▼]

Finding water(-ice) on the Moon is key to enabling a sustainable human presence on the Moon and beyond. There is evidence that water-ice is abundant in and around the Moon’s Permanently Shadowed Regions (PSRs), however, direct visual detection has not yet been possible. Surface ice or related physical features could potentially be directly detected from high-resolution optical imagery, but, due to the extremely low-light conditions in these areas, high levels of sensor and photon noise make this very challenging. In this work we generate high-resolution, low-noise optical images over lunar PSRs by using two physics-based deep neural networks to model and remove CCD-related and photon noise in existing low-light optical imagery, potentially paving the way for a direct water-ice detection method. [less ▲]

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See detailPrivacy-Preserving Logistic Regression as a Cloud Service Based on Residue Number System
Cortés-Mendoza, Jorge; Tchernykh, Andrei; Babenko, Mikhail et al

in Voevodin, Vladimir; Sobolev, Sergey (Eds.) 6th Russian Supercomputing Days, Moscow 21-22 September 2020 (2020, December)

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See detailEvaluating Pretrained Transformer-based Models on the Task of Fine-Grained Named Entity Recognition
Lothritz, Cedric UL; Allix, Kevin UL; Veiber, Lisa UL et al

in Proceedings of the 28th International Conference on Computational Linguistics (2020, December)

Named Entity Recognition (NER) is a fundamental Natural Language Processing (NLP) task and has remained an active research field. In recent years, transformer models and more specifically the BERT model ... [more ▼]

Named Entity Recognition (NER) is a fundamental Natural Language Processing (NLP) task and has remained an active research field. In recent years, transformer models and more specifically the BERT model developed at Google revolutionised the field of NLP. While the performance of transformer-based approaches such as BERT has been studied for NER, there has not yet been a study for the fine-grained Named Entity Recognition (FG-NER) task. In this paper, we compare three transformer-based models (BERT, RoBERTa, and XLNet) to two non-transformer-based models (CRF and BiLSTM-CNN-CRF). Furthermore, we apply each model to a multitude of distinct domains. We find that transformer-based models incrementally outperform the studied non-transformer-based models in most domains with respect to the F1 score. Furthermore, we find that the choice of domains significantly influenced the performance regardless of the respective data size or the model chosen. [less ▲]

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See detailOut-of-the-box Multipath TCP as a Tor Transport Protocol: Performance and Privacy Implications
de La Cadena Ramos, Augusto Wladimir UL; Kaiser, Daniel UL; Panchenko, Andriy UL et al

in 19th IEEE International Symposium on Network Computing and Applications (IEEE NCA 2020) (2020, November 25)

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See detailHeuristic Evaluation of COVID-19 Chatbots
Hoehn, Sviatlana UL; Bongard, Kerstin UL

in Proceedings of CONVERSATIONS 2020 (2020, November 23)

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See detailTrafficSliver: Fighting Website Fingerprinting Attacks with Traffic Splitting
de La Cadena Ramos, Augusto Wladimir UL; Mitseva, Asya; Hiller, Jens et al

in 27th ACM Conference on Computer and Communications Security (CCS '20) (2020, November 13)

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See detailBeyond School Effects: Private Schooling, Segregation and Standardization of School Systems in Latin America
Ceron, Francisco UL

in Tackling Educational Inequalities in Luxembourg and Beyond. Abstract Booklet (2020, November 11)

The design of educational institutions may face policy trade-offs in the tasks of school systems that are served by them (van de Werfhorst and Mijs, 2010; Pedró et al 2015). Differentiation of school ... [more ▼]

The design of educational institutions may face policy trade-offs in the tasks of school systems that are served by them (van de Werfhorst and Mijs, 2010; Pedró et al 2015). Differentiation of school systems may foster efficient sorting of students and then maximize learnings but at the cost of exacerbating social inequalities. A centralized education system may guarantee equality of educational opportunities, but it is not clear if it increases or hinder the overall performance level (e.g. Woessman 2003; Brunello & Checchi 2007; Bol et al., 2014; Bol & van de Werfhorst, 2016; Mijs 2016). Until now, researchers have overlooked the role of private schooling as an important dimension of stratification in national school systems, focusing mainly on its relative effectiveness and assuming implicitly that school sector capacity truly reflects a level of differentiation (e.g. Hanushek & Woessman, 2015; Chmielewski & Reardon 2016). I attempt to address the following research question: to what extend the differentiation induced by private schooling increase achievement inequalities, counteracting the effects of standardization of the school systems in Latin American countries? Using data from the 2013 UNESCO TERCE regional large-scale assessment, I study how private schooling is related to overall levels of stratification and the extent to which it affects achievement inequality in a context of varying levels of standardization, across countries. I construct a generalized entropy measure of segregation to capture system level differentiation induced by private schooling, a standardization index (Bol & van de Werfhorst, 2016) and by using multilevel models with county fixed effects, I find that private schooling counterbalance the equalizing effect of higher levels of standardization on achievement inequalities, no matter their relative size, on top of individual and school level controls. I conclude by discussing how these findings speak to the potential policy trade-off between equality and efficiency in the region. [less ▲]

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See detailMixed method situational review of primary family violence care in IMOCAFV
Ares Blanco, Sara; Frese, Thomas; Lacatus, Anca et al

in 90th European General Practice Research Network Meeting (2020, November 10)

Background: The ‘IMOCAFV’ project is developing a multi-country vision on how to provide effective primary care for family violence (FV). In phase I, a situational analysis is performed based on mixed ... [more ▼]

Background: The ‘IMOCAFV’ project is developing a multi-country vision on how to provide effective primary care for family violence (FV). In phase I, a situational analysis is performed based on mixed method review of countries’ policies and interventions, key persons inquiries and professional questionnaires. Aim: Provide in a first phase of IMOCAFV a mixed methods analysis of policies and interventions for primary FV care in different health care settings, high, low and middle income countries. Research questions: How to perform a multi-level in depth mixed method analysis of policies, protocols, problems and good practices on primary FV care? Method: National guidance for FV primary care tasks is centralised into a central online database. Documentation is reviewed online nationally answering questions about prevention, detection, assessment and collaborative care for intimate partner violence, child abuse and elder abuse. Semistructured online inquiries are sent to a pragmatic sample of key persons and professionals in each country. Online training provides guidance for standardized mixed method review of materials. A continuous comparative analysis is made at local and international level; it should provide cues for the Delphi study planned in the second phase. Results: The key questionnaire describes policies and interventions defined for primary health care and advocacy support in different health services settings in three continents. The professional questionnaire describes problems encountered and professionals opinion´s. Different online software packages are suitable for international research collaboration with some limitations. Ethical and security requirements may differ, while high security level applications require more budgets. Conclusions: The organisation of a two-level international qualitative analysis is challenging from a methodological and organisational point of view. A qualitative analysis in a multilanguage context requires specific agreements. Challenges will be discussed using first results. Points for discussion: 1.How to facilitate a good qualitative analysis at both national and international level? 2.How to use different software platforms taking into account countries’ different requirements and organisational facilities in different income countries? [less ▲]

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See detailSpecifying key-properties to improve the recognition skills of neural networks
Jahic, Benjamin UL; Guelfi, Nicolas UL; Ries, Benoit UL

in Proceedings of the 2020 European Symposium on Software Engineering (2020, November 06)

Software engineers are increasingly asked to build datasets for engineering neural network-based software systems. These datasets are used to train neural networks to recognise data. Traditionally, data ... [more ▼]

Software engineers are increasingly asked to build datasets for engineering neural network-based software systems. These datasets are used to train neural networks to recognise data. Traditionally, data scientists build datasets consisting of random collected or generated data. Their approaches are often costly, inefficient and time-consuming. Software engineers rely on these traditional approaches that do not support precise data selection criteria based on customer’s requirements. In this paper, we introduce an extended software engineering method for dataset augmentation to improve neural networks by satisfying the customer’s requirements. We introduce the notion of key-properties to describe the neural network’s recognition skills. Key-properties are used all along the engineering process for developing the neural network in cooperation with the customer. We propose a rigorous process for augmenting datasets based on the analysis and specification of the key-properties. We conducted an experimentation on a case study on the recognition of the state of a digital meter counter. We demonstrate an informal specification of the neural network’s key-properties and a successful improvement of a neural network’s recognition of the meter counter state. [less ▲]

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See detailGraph Diffusion Kernel LMS using Random Fourier Features
Gogineni, Vinay; Elias, Vitor R. M.; Alves Martins, Wallace UL et al

in 2020 54th Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, USA, 1-5 November 2020 (2020, November)

This work introduces kernel adaptive graph filters that operate in the reproducing kernel Hilbert space. We propose a centralized graph kernel least mean squares (GKLMS) approach for identifying the ... [more ▼]

This work introduces kernel adaptive graph filters that operate in the reproducing kernel Hilbert space. We propose a centralized graph kernel least mean squares (GKLMS) approach for identifying the nonlinear graph filters. The principles of coherence-check and random Fourier features (RFF) are used to reduce the dictionary size. Additionally, we leverage on the graph structure to derive the graph diffusion KLMS (GDKLMS). The proposed GDKLMS requires only single-hop communication during successive time instants, making it viable for real-time network-based applications. In the distributed implementation, usage of RFF avoids the requirement of a centralized pretrained dictionary in the case of coherence-check. Finally, the performance of the proposed algorithms is demonstrated in modeling a nonlinear graph filter via numerical examples. The results show that centralized and distributed implementations effectively model the nonlinear graph filters, whereas the random feature-based solutions is shown to outperform coherence-check based solutions. [less ▲]

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See detailImpact of Congestion Pricing Policies in Round-Trip and Free-Floating Carsharing Systems
Cisterna, Carolina UL; Giorgione, Giulio UL; Viti, Francesco UL

in Nathail, Eftihia (Ed.) Advances in Mobility-as-a-Service Systems (2020, November)

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See detailSeparation of Concerns Within Robotic Systems Through Proactive Computing
Frantz, Alexandre; Zampunieris, Denis UL

in Proceeding of the 4th IEEE International Conference on Robotic Computing (2020, November)

In this short paper, we first introduce a possible new model for designing and implementing software in robotic systems. This model is based on proactive scenarios, coded through dynamic sets of condition ... [more ▼]

In this short paper, we first introduce a possible new model for designing and implementing software in robotic systems. This model is based on proactive scenarios, coded through dynamic sets of condition-action rules. Each scenario embeds the required rules and can be assembled dynamically with others, allowing the proactive system to achieve a unique objective or behavior and instruct the robot accordingly. Furthermore, a scenario is not aware of the existence of the other scenarios. In fact, it only contains information about a predefined central scenario, which oversees global decision making. In addition, each scenario knows where to enter its suggestions, thus allowing for a high degree in terms of separating concerns and modularity of code. Consequently, allowing easier development, testing and optimization of each scenario independently, possible reuse in different robots, and finally, a faster achievement of robust and scalable robotics software. We then show how to apply this programming model and its functionalities during runtime, by a proof of concept consisting of a virtual robot deployed in the Webots™ simulator. This simulator is controlled with four proactive scenarios (plus the central one), in charge of three different objectives. [less ▲]

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See detailDiffusion-based Virtual Graph Adjacency for Fourier Analysis of Network Signals
Elias, Vitor R. M.; Alves Martins, Wallace UL; Werner, Stefan

in XXXVIII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS, Florianópolis 22-25 November 2020 (2020, November)

This work proposes a graph model for networks where node collaborations can be described by the Markov property. The proposed model augments an initial graph adjacency using diffusion distances. The ... [more ▼]

This work proposes a graph model for networks where node collaborations can be described by the Markov property. The proposed model augments an initial graph adjacency using diffusion distances. The resulting virtual adjacency depends on a diffusion-scale parameter, which leads to a controlled shift in the graph-Fourier-transform spectrum. This enables a frequency analysis tailored to the actual network collaboration, revealing more information on the graph signal when compared to traditional approaches. The proposed model is employed for anomaly detection in real and synthetic networks, and results confirm that using the proposed virtual adjacency yields better classification than the initial adjacency. [less ▲]

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See detailAn SKOS-Based Vocabulary on the Swift Programming Language
Grevisse, Christian UL; Rothkugel, Steffen UL

in The Semantic Web – ISWC 2020 (2020, November)

Domain ontologies about one or several programming languages have been created in various occasions, mostly in the context of Technology Enhanced Learning (TEL). Their benefits range from modeling ... [more ▼]

Domain ontologies about one or several programming languages have been created in various occasions, mostly in the context of Technology Enhanced Learning (TEL). Their benefits range from modeling learning outcomes, over organization and annotation of learning material, to providing scaffolding support in programming labs by integrating relevant learning resources. The Swift programming language, introduced in 2014, is currently gaining momentum in different fields of application. Both its powerful syntax as well as the provided type safety make it a good language for first-year computer science students. However, it has not yet been the subject of a domain ontology. In this paper, we present an SKOS-based vocabulary on the Swift programming language, aiming at enabling the benefits of previous research for this particular language. After reviewing existing ontologies on other programming languages, we present the modeling process of the Swift vocabulary, its integration into the LOD Cloud and list all of its resources available to the research community. Finally, we showcase how it is being used in different TEL tools. [less ▲]

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See detailDemountable and reusable construction system for steel-concrete composite structures
Odenbreit, Christoph UL; Kozma, Andras UL

in Odenbreit, Christoph; Kozma, Andras (Eds.) Demountable and reusable construction system for steel-concrete composite structures (2020, October 30)

In the face of climate change and the depletion of finite resources, sustainability is becoming increasingly important recently. This is especially true in the construction industry that is responsible ... [more ▼]

In the face of climate change and the depletion of finite resources, sustainability is becoming increasingly important recently. This is especially true in the construction industry that is responsible for the 11% of global carbon dioxide emissions. Besides the technological improvements, the emissions can be further reduced by the application of the principles of the circular economy. This concept is based on the efficient allocation of resources. Three terms are frequently used when talking about this concept: reduce, reuse and recycle. Reducing is cut-ting back on the amount of waste we produce, reusing is finding a new way to use our products so that they do not be-come waste, and recycling is using the materials of our products to produce new materials. The traditional life-cycle of a building usually follows a linear model from the extraction of the raw materials through material production, component manufacturing, construction and building use, until when finally the building is demolished and most of the materials become debris and go into landfill. This is in direct opposition with the concept of circular economy. With proper considerations at the design stage, it is possible to deconstruct whole buildings and re-erect them elsewhere. In the frame of the RFCS Research Project “REDUCE” of the European Commission, a demountable and reusable construction system for steel-concrete composite structures has been recently developed. The system is based on a modular “kit-of-parts” system that uses prefabricated and standardised elements that are easy to manufacture and to assemble with the help of standardised connections. The elements were designed in a systematic way such that, a wide variety of different configurations are possible. In this system, the geometry of all elements respects the planning grid that is based on a basic module size. The research included the development and structural testing of novel demountable and adjustable structural solutions including beam-to-slab, beam-to-beam and beam-to-column connections. During the development of the structural solutions the following aspects were considered: structural performance, safety, installation and tolerances, demountability, corrosion resistance, aesthetics, economy, adaptability, standardisation and environmental impact. The laboratory testing was supplemented by nonlinear numerical studies using the finite element software ABAQUS. Based on the results and the experiences obtained throughout the research project, a design proposal was prepared. One objective of the project was to find structural solutions that are easily applicable and compatible with the current standard de-sign rules. The proposed beam-to-beam and beam-to-column joint is in the scope of EN1993-1-8. The new shear connections behave differently than the traditionally applied welded studs. The cor-responding standard would not allow the equidistant placement of the connectors nor the application of the partial shear theory. This would make the use of demountable shear connections complicated and uneconomical. In order to overcome this issue, a simple algorithm was developed that transforms the elastic-brittle shear connection behaviour into an equivalent ductile rigid-plastic behaviour so that the Eurocode 4 design rules for the determination of the moment resistance of composite beams with partial shear connection remain applicable. The design proposal also contains recommendations to maximize the reuse potential of the building components. This paper presents a general overview of the developed construction system and the corresponding laboratory tests and numerical studies as well as recommendations for the design and application of de-mountable and reusable composite structures. [less ▲]

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See detailBUILDING A PIECE OF THE MOON: CONSTRUCTION OF TWO INDOOR LUNAR ANALOGUE ENVIRONMENTS
Ludivig, Philippe UL; Calzada-Diaz, Abigail; Olivares Mendez, Miguel Angel UL et al

in Proceedings of the 71st International Astronautical Congress 2020 (2020, October 12)

Developing and testing autonomous systems to ensure that they work reliably on the moon is a difficult task, as testing on location is not an option. Instead, engineers rely on simulations, testing ... [more ▼]

Developing and testing autonomous systems to ensure that they work reliably on the moon is a difficult task, as testing on location is not an option. Instead, engineers rely on simulations, testing facilities and outdoor lunar analogues. Due to the lack of lunar analogue testing facilities in Europe, ispace Europe and the University of Luxembourg have teamed up to build two of these facilities with the goal of designing new vision-based navigation systems. These systems will enable autonomous long-range traverses for lunar rovers. These two facilities have a surface area of 64 and 77 square meters, respectively. Regarding the type of testing needed for vision-based systems, the optical fidelity of the environment has been considered as the most important factor. Thus, different types of Basalt have been used for the two facilities to create a larger number of possible landscapes, such as craters, hills, rocky areas and smooth planar surfaces. Regolith simulant was also considered but, due to the health restrictions and the cost factor, basalt was selected instead. As a result, this has allowed for larger testing areas. The illumination setup has been designed to simulate the highland regions of the Moon, with a single light source positioned low above the horizon, casting long shadows over the entire area. To mitigate problems with feature detection algorithms picking up features at the edge of the facility, the walls have been painted black. This also produces high contrast shadows, which is exactly what makes vision-based navigation challenging in the polar regions. The outcome of this research is a set of lessons learned which will enable other researchers to replicate similar facilities and to reproduce the same fidelity in indoor testing for future vision-based navigation systems. [less ▲]

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See detailBuilding up Explainability in Multi-layer Perceptrons for Credit Risk Modeling
Sharma, Rudrani; Schommer, Christoph UL; Vivarelli, Nicolas

in Sharma, Rudrani (Ed.) Building up Explainability in Multi-layer Perceptrons for Credit Risk Modeling (2020, October 09)

Granting loans is one of the major concerns of financial institutions due to the risks of default borrowers. Default prediction by the neural networks is a popular technique for credit risk modeling ... [more ▼]

Granting loans is one of the major concerns of financial institutions due to the risks of default borrowers. Default prediction by the neural networks is a popular technique for credit risk modeling. Neural networks generally offer the accurate predictions that help banks to prevent financial losses and grow their business by approving more creditworthy borrowers. Although neural networks are capable of capturing the complex, non-linear relationships between a large number of features and output, these models act as black boxes. This is a graduation project paper that is focused on loan default risk prediction by multi-layer perceptron neural network and building up explainability to some degree in the trained neural networks through sensitivity analysis. The architecture of a multi-layer perceptron neural network with the best result is used to help the credit-risk manager in explaining why an applicant is a defaulter or non-defaulter. The prediction of a trained multi-layer perceptron neural network is explained by mapping input features and target variables directly using a model-agnostic explanation as well as a modelspecific explanation. Lastly, a comparison is performed between two explanation methods. [less ▲]

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See detailHybrid Analog-Digital Precoding for mmWave Coexisting in 5G-Satellite Integrated Network
Peng, D.; Li, Y.; Chatzinotas, Symeon UL et al

in 2020 IEEE 31st Annual International Symposium on Personal, Indoor and Mobile Radio Communications, title=Hybrid Analog-Digital Precoding for mmWave Coexisting in 5G-Satellite Integrated Network (2020, October 08)

Integrating massive multiple-input multiple-output (MIMO) into satellite network is regarded as an effective strategy to improve the spectral efficiency as well as the coverage of satellite communication ... [more ▼]

Integrating massive multiple-input multiple-output (MIMO) into satellite network is regarded as an effective strategy to improve the spectral efficiency as well as the coverage of satellite communication. However, the inevitable intra-system and inter-system interference deteriorate the total performance of system. In this paper, we consider precoding in the 5G Satellite Integrated Network (5GSIN) with the deployment of Massive MIMO and propagation of shared millimeter-wave (mmWave) link. Taking the requirements of both frequency efficiency and energy assumption into account, a hybrid analog and digital pre-coding scheme in the specific scenario of 5GSIN is proposed. We model sum rate maximization problem for both of satellite and terrestrial system that incorporates maximum power constrains and minimum achievable rate requirements and formulate to a convex power allocation problem with Minimum Mean Square Error (MMSE) norm and Logarithmic Linearization method. In order to balance between performance and complexity, we propose an analog and digital separated hybrid precoding algorithm to mitigate intra-system interference. Moreover, an iterative power allocation with interference mitigation algorithm is also devised to mitigate interference from satellite to terrestrial link so that power allocation can be executed by generalized iterative algorithm. Simulation results show that our proposed hybrid precoding algorithm in 5GSIN can improve the overall spectral efficiency with a small amount of iterations. [less ▲]

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See detailAll for one and one for all: Recommendations for Sustainable International Lunar Base Utilization and Exploration Approaches
Salmeri, Antonino UL; Poliacek, Matej

in Proceedings of the 71st International Astronautical Congress - The Cyberspace Edition (2020, October)

The return to the Moon is widely regarded as the next step of space exploration. Fifty years after the first Apollo mission, a renewed interest is fostering large global efforts in pursuing the scientific ... [more ▼]

The return to the Moon is widely regarded as the next step of space exploration. Fifty years after the first Apollo mission, a renewed interest is fostering large global efforts in pursuing the scientific and economic opportunities offered by cislunar space. The ultimate goal is to establish a sustainable human and robotic presence on the lunar surface as specified in Phase 2 of NASA’s Artemis Program. These perspectives are deeply intertwined with the rapid growth of the private space sector and the arising geopolitical complexities, related to utilisation of outer space among space-faring nations. This study summarises the results and recommendations of the NASA-sponsored Space Exploration Working Group within the Space Generation Congress 2019, organised by the Space Generation Advisory Council in Washington, D.C. The Working Group consisted of 26 delegates from 15 different countries and representatives from NASA Headquarters. The group examined the evolution of lunar exploration in terms of international cooperation, socio-economic and technological challenges, and the inclusion of private industry. This report discusses the political, economic, and technological trade-offs between a multi-agency/multinational monolithic lunar base to multiple lunar bases operated by individual nations. Using the International Space Station as a model for international cooperation, the working group concluded that an initial infrastructure of a single station requiring a collaborative effort between nations and commercial stakeholders is the recommended approach. From this foothold, the presence is expanded to multiple bases with a standardization of planning, building, and operating lunar bases. Strategic recommendations were identified to be addressed to the United Nations and other public/private stakeholders with the vision of a cooperative legal and technical framework as the optimal foundation for a sustainable lunar economy. Recommendations include developing international guidelines for cooperation, establishing international standards for stakeholders, implementing conflict resolution avenues, configuring a single international base, and expanding global partnerships. [less ▲]

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See detailAPIS: Applications and Potentials of Intelligent Swarms for magnetospheric studies
Rajan, Raj Thilak; Salmeri, Antonino UL; Haken, Dawn et al

in Proceedings of 71st International Astronautical Congress - The Cyberspace Edition (2020, October)

Earth's magnetosphere is vital for today's technologically dependent society. The energy transferred from the solar wind to the magnetosphere triggers electromagnetic storms on Earth, knocking out power ... [more ▼]

Earth's magnetosphere is vital for today's technologically dependent society. The energy transferred from the solar wind to the magnetosphere triggers electromagnetic storms on Earth, knocking out power grids and infrastructure | e.g., communication and navigation systems. Despite occurring on our astrophysical doorstep, numerous physical processes connecting the solar wind and our magnetosphere remain poorly understood. To date, over a dozen science missions have own to study the magnetosphere, and many more design studies have been conducted. However, the majority of these solutions relied on large monolithic satellites, which limited the spatial resolution of these investigations, in addition to the technological limitations of the past. To counter these limitations, we propose the use of a satellite swarm, carrying numerous payloads for magnetospheric measurements. Our mission is named APIS | Applications and Potentials of Intelligent Swarms. The APIS mission aims to characterize fundamental plasma processes in the magnetosphere and measure the e ect of the solar wind on our magnetosphere. We propose a swarm of 40 CubeSats in two highly- elliptical orbits around the Earth, which perform radio tomography in the magnetotail at 8{12 Earth Radii (RE) downstream, and the subsolar magnetosphere at 8{12 RE upstream. These maps will be made at both low-resolutions (at 0.5 RE, 5 seconds cadence) and high-resolutions (at 0.025 RE, 2 seconds cadence). In addition, in-situ measurements of the magnetic and electric elds, and plasma density will be performed by on-board instruments. In this publication, we present a design study of the APIS mission, which includes the mission design, navigation, communication, processing, power systems, propulsion and other critical satellite subsystems. The science requirements of the APIS mission levy stringent system requirements, which are addressed using Commercial O -the-Shelf (COTS) technologies. We show the feasibility of the APIS mission using COTS technologies using preliminary link, power, and mass bud- gets. In addition to the technological study, we also investigated the legal considerations of the APIS mission. The APIS mission design study was part of the International Space University Space Studies Program in 2019 (ISU-SSP19) Next Generation Space Systems: Swarms Team Project. The authors of [less ▲]

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See detailWaste Management for Lunar Resources Activities: Towards a Circular Lunar Economy
Salmeri, Antonino UL; Pino, Paolo; Humes, Shayna et al

in Proceedings of the 71st International Astronautical Congress - The Cyberspace Edition (2020, October)

Space resources activities are currently the objective of a thriving, cross-disciplinary, global effort aimed at assessing their role and potential in the future of humankind. New, innovative mission ... [more ▼]

Space resources activities are currently the objective of a thriving, cross-disciplinary, global effort aimed at assessing their role and potential in the future of humankind. New, innovative mission concepts, legal frameworks, and advanced technologies are being actively developed and proposed with the final goal of enabling profitable and efficient space resource utilization. The immediate location for these impacts is the Moon. In sight of this bright cohort of imminent perspectives, it’s imperative for the global community to properly assess the potential effects and consequences of the forthcoming space resources activities, with the goal of including sustainability in the foundations of the ongoing progress and ensuring its enforcement in every future endeavour. Within this context, this paper addresses the topics of Moon mining waste management and a lunar circular economy as key issues in the sustainable utilization of space resources. The most promising technologies are considered for lunar resources extraction and processing - with special focus on water - correlating their waste generation potential to the scale of the efforts implemented and to the projected availability of the resources of interest. Importance is also given to the corollary activities of space mining - such as logistics and transport operations - for their implications in waste management. Protocols and technologies with the lower waste generation potential are identified and further scenarios are elaborated for waste handling, reduction, reuse, and recycle, as well as end-of-life strategies for mining plants. This report’s recommendations are proposed for the development of incremental regulation for waste management, including but not limited to the definition of common areas of non-interest for waste disposal and regulatory obligations for conducting impact assessments before the establishment of mining activities. Please note that the present paper has been developed under the auspices of the Space Generation Advisory Council, as part of the activities of the Space Exploration Project Group. [less ▲]

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See detailDer Wert digitaler Güter - Steuerrechtliche Einordnung
Sinnig, Julia UL

in Gräfe, Hans-Christian; Telemedicus e.V. (Eds.) Tagungsband zur Sommerkonferenz 2019: Über den Tellerrand (2020, October)

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See detailA Social License to Operate for Lunar Resources Activities: Towards a Fair and Sustainable Era of Space Exploration
Salmeri, Antonino UL; Villegas, Maria Camila

in Proceedings of the 71st International Astronautical Congress - The Cyberspace Edition (2020, October)

Five years ago, soon after his nomination as ESA Director General, Jan Wörner announced the concept of a Moon Village as “an environment where both international cooperation and the commercialization of ... [more ▼]

Five years ago, soon after his nomination as ESA Director General, Jan Wörner announced the concept of a Moon Village as “an environment where both international cooperation and the commercialization of space can thrive”. Today, this concept is more alive than ever and is rapidly moving to its implementation through a series of lunar resources missions planned for as soon as 2021. In line with the spirit of cooperation and sustainability of the Moon Village, this paper addresses how lunar resources activities can become a model for fair and sustainable space exploration through the development of a Social License to Operate (SLO). SLO is defined as the efforts made by a company or entity in order to give back part of the wealth it produces to the community where it operates. On Earth, this is usually done through environmentally friendly practices, information disclosure and a various range of activities aimed at community support such as job creations, educational activities and technology transfer. Mutatis mutandis, current Earth practice on SLO can be implemented in lunar resources activities in order to ensure that they are conducted “for the benefit and interest of all Countries”, as required by Article I OST. Building on the research conducted by the Socio-Economic Panel of The Hague International Space Resources Governance Working Group, this paper explores how the development of a Social License to Operate for Lunar activities can shape a new era of fair and sustainable space exploration. Guided by the principle of adaptive governance, the paper presents the benefits of Lunar SLOs as tailored for the early stages of lunar activities. To this end, Chapter 1 presents the definition of SLO, how it is used on Earth, the experience of some countries, and the way it is granted. Following, Chapter 2 discusses the rationale for implementing SLOs for lunar activities, and how they can contribute to the early development of lunar activities. Based on the above, Chapter 3 discusses three basic features for Lunar SLOs, arguing that they should be multigoverned, multipurposes and multi-incentives. Finally, Section 4 provides a practical example of how a Lunar SLO could be structured in practice, and then the paper draws the final conclusions. Please note that this paper has been developed under the auspices of the Space Generation Advisory Council, as part of the activities of the Space Exploration Project Group [less ▲]

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See detailEco-construction for sustainable development (Econ4SD) – Konzepte für Materialbanken
Zilian, Andreas UL; Waldmann, Daniele UL; Hertweck, Florian UL et al

in Kaliske, Michael (Ed.) 24. Dresdner Baustatik-Seminar: Reality - Modeling - Structural Design (2020, October)

This contribution presents the joint research project Econ4SD – Eco-construction for sustainable development which investigates at the University of Luxembourg various aspects of sustainable design ... [more ▼]

This contribution presents the joint research project Econ4SD – Eco-construction for sustainable development which investigates at the University of Luxembourg various aspects of sustainable design, construction and operation to support a resource-efficient circular economy in the construction sector. In this context the fundamental approach of Design for deconstruction assumes a central role and is being discussed together with the complementary concept of Material banks and their digital twinning at the level of components, buildings and markets. [less ▲]

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See detailSporty summer and lazy winter? PA of youth from a seasonal perspective.
Eckelt, Melanie UL; Hutmacher, Djenna UL; Steffgen, Georges UL et al

in Dela, Flemming; Müller, Erich; Tsolakidis, Elias (Eds.) Book of Abstracts (2020, October)

Objectives: Many children in Europe are insufficiently active (1), which makes the promotion of children´s physical activity (PA) a critical health promotion target. However, there are some uncontrollable ... [more ▼]

Objectives: Many children in Europe are insufficiently active (1), which makes the promotion of children´s physical activity (PA) a critical health promotion target. However, there are some uncontrollable factors such as amount of daylight, weather conditions, temperatures and precipitation levels that might influence PA behavior (2). Conditions for moderate to vigorous physical activity (MVPA) seem to be optimal when the environmental temperature ranges between 20°C and 25°C (3). This study aims to examine if the season is related to the objectively measured PA of youth of Luxembourg. Methods: 150 youth (90 females and 60 males) aged from 10–17 (M = 12.37, SD = 2.14) years participated in this longitudinal study, which took place at two measurement periods, the first between October and December (winter) and the second between May and July (summer). PA behavior was objectively assessed by wearing an accelerometer (ActiGraph GT3X-BT) for seven consecutive days. Daily time spent in MVPA was calculated as an indicator of the youth’s PA behavior. Results: A repeated measures ANOVA revealed a significant seasonal effect for MVPA per day (F(1, 1136.66) = 9.14, p < .05, partial η² = .06). More minutes of MVPA per day were accrued in summer (M = 53.24, SD = 21.40) than in winter (M = 49.04, SD = 20.88). Both in winter and in summer, MVPA per day differed significantly between females and males (winter: t(148) = 5.83, p < .001; summer: t(148) = 4.85, p < .001), whereby females (winter: M = 41.70, SD = 15.89; summer: M = 46.79, SD = 17.26) showed significantly fewer minutes in MVPA per day than males (winter: M = 60.05, SD = 22.67; summer: M = 62.91, SD = 23.43). However, there was no significant interaction between season and gender, F(1, 89.85) = .723, p = .397). Discussion: According to the results of this study, youth are less physically active in winter than in summer. Therefore, schools, sports clubs and communities should offer special PA programs for this season, which are independent from climatic conditions and equally suitable for females and males. Measuring PA throughout the year enables to monitor the activity behavior more accurate and may help in developing such programs. [less ▲]

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See detailComparison of Multidisciplinary Design Optimization Architectures for the design of Distributed Space Systems
Pandi Perumal, Raja UL; Voos, Holger UL; Dalla Vedova, Florio et al

in Pandi Perumal, Raja; Voos, Holger; Dalla Vedova, Florio (Eds.) et al Proceedings of the 71st International Astronautical Congress 2020 (2020, October)

Advancement in satellite technology, and the ability to mass-produce cost-effective small satellites has created a compelling interest in Distributed Space System (DSS), such as Low Earth Orbit (LEO ... [more ▼]

Advancement in satellite technology, and the ability to mass-produce cost-effective small satellites has created a compelling interest in Distributed Space System (DSS), such as Low Earth Orbit (LEO) satellite constellations. Optimization of DSS is a complex Multidisciplinary Design Optimization (MDO) problem involving a large number of variables and coupling relations. This paper focuses on comparing three different MDO architectures for a DSS design problem. Initially, an overview of the constellation model, the subsystems model, and the coupling relationships between the subsystems and the constellation are provided. The modelling of the subsystems and the constellation configuration are carried out in OpenMDAO. Later, three monolithic MDO architectures, namely, Individual Discipline Feasible (IDF), Simultaneous Analysis and Design (SAND) and Multidisciplinary Feasible (MDF) are compared by implementing them to the developed DSS model. The results indicate IDF outperforms the rest of the architectures for the conceptual design of DSS. The optimum objective function obtained by IDF is 1% lower than SAND and 7% lower than MDF. While the functional evaluation required for IDF is 50% lower than SAND and 90% lower than MDF. [less ▲]

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See detail3D SPARSE DEFORMATION SIGNATURE FOR DYNAMIC FACE RECOGNITION
Shabayek, Abd El Rahman UL; Aouada, Djamila UL; Cherenkova, Kseniya UL et al

in 27th IEEE International Conference on Image Processing (ICIP 2020), Abu Dhabi 25-28 October 2020 (2020, October)

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See detailFractional Linear Prediction Toolbox for MATLAB
Despotovic, Vladimir UL; Skovranek, Tomas

in Proc. of 21th International Carpathian Control Conference (ICCC) (2020, October)

This paper presents the Fractional Linear Prediction (FLP) Toolbox implemented in MATLAB with a supporting livescript interface that offers an user-friendly environment for the prediction of one ... [more ▼]

This paper presents the Fractional Linear Prediction (FLP) Toolbox implemented in MATLAB with a supporting livescript interface that offers an user-friendly environment for the prediction of one-dimensional signals. Two versions of the FLP are implemented in the toolbox and presented here. While the first approach is using the “full” memory (the whole history of the signal), the second approach uses the “restricted” memory (two, three or four previous samples). Both FLP approaches are compared to the standard linear prediction and their performance is evaluated in examples using a test signal (sine wave signal), and a real-data signal (speech signal) as the input. [less ▲]

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See detailDeveloping and Managing Moon and Mars Settlements in Accordance with International Space Law
Salmeri, Antonino UL

in Proceedings of the 71st International Astronautical Congress 2020 (2020, October)

Despite still being a few decades in the future, the idea of establishing an extra-terrestrial settlement on another celestial body, being it the Moon or Mars, has never been so strong. Moving from the ... [more ▼]

Despite still being a few decades in the future, the idea of establishing an extra-terrestrial settlement on another celestial body, being it the Moon or Mars, has never been so strong. Moving from the premise that future Moon and Mars settlements shall not take place in a lawless space, this paper addresses the question of how to develop and manage them in accordance with international space law. To this end, it conducts a systematic analysis of the Outer Space Treaty (OST), with the goal of assessing the scope of the freedom to use celestial bodies under international space law. Based on this analysis, and building on the successful experience of the International Space Station, the paper proposes the development of open international settlements made of shared modular facilities. In accordance with the principles of adaptive governance and subsidiarity, the paper argues that the regulation of such settlements should be based on a multi-level framework integrating international recommendations and bilateral arrangements. Under the proposed governance scheme, international recommendations should provide a general framework enabling the development of the settlement, while leaving its management to the mutual agreement of the parties. Finally, the paper presents four essential goals to be achieved by the recommendations and ultimately concludes by arguing that while international cooperation in the development and management of extra-terrestrial settlements is not a legal obligation, it may very well be the only political option that we have to preserve the peaceful uses of outer space. [less ▲]

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See detailLeveraging Natural-language Requirements for Deriving Better Acceptance Criteria from Models
Veizaga Campero, Alvaro Mario UL; Alferez, Mauricio UL; Torre, Damiano UL et al

in Proceedings of 23rd ACM / IEEE International Conference on Model Driven Engineering Languages and Systems (MODELS) (2020, October)

In many software and systems development projects, analysts specify requirements using a combination of modeling and natural language (NL). In such situations, systematic acceptance testing poses a ... [more ▼]

In many software and systems development projects, analysts specify requirements using a combination of modeling and natural language (NL). In such situations, systematic acceptance testing poses a challenge because defining the acceptance criteria (AC) to be met by the system under test has to account not only for the information in the (requirements) model but also that in the NL requirements. In other words, neither models nor NL requirements per se provide a complete picture of the information content relevant to AC. Our work in this paper is prompted by the observation that a reconciliation of the information content in NL requirements and models is necessary for obtaining precise AC. We perform such reconciliation by devising an approach that automatically extracts AC-related information from NL requirements and helps modelers enrich their model with the extracted information. An existing AC derivation technique is then applied to the model that has now been enriched by the information extracted from NL requirements. Using a real case study from the financial domain, we evaluate the usefulness of the AC-related model enrichments recommended by our approach. Our evaluation results are very promising: Over our case study system, a group of five domain experts found 89% of the recommended enrichments relevant to AC and yet absent from the original model (precision of 89%). Furthermore, the experts could not pinpoint any additional information in the NL requirements which was relevant to AC but which had not already been brought to their attention by our approach (recall of 100%) [less ▲]

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See detailMULTI-LEVEL INFORMATION VALUE STREAM MAPPING
Mangers, Jeff UL; Thoussaint, Lou; Minoufekr, Meysam UL et al

in Proceedings of the 9th International Conference on Mass Customization and Personalization - Community of Europe (MCP-CE 2020) (2020, September 25)

Digitalization and automation of the production according to Industry 4.0 opens new opportunities for companies to develop more efficient value chains. In the context of mass customization, it is ... [more ▼]

Digitalization and automation of the production according to Industry 4.0 opens new opportunities for companies to develop more efficient value chains. In the context of mass customization, it is promising to examine more closely the complete internal value chain of companies, from the first customer contact to the delivery of the finished product, prior to provide digital configurations for customized products. A critical aspect for internal inefficiencies and complication of an aspired automation are the interfaces of departments due to inconsistent and non-uniform information transfer. This article presents a versatile approach to visualize the internal information flow at inter-departmental level as well as at intra-departmental level. The described multilevel information value stream mapping method perfectly suits as prerequisite for a digitalization or automation of internal information flows. As framework for the time capturing and visualization, ISO 22468 is used, and an industrial use case exemplifies the research findings. [less ▲]

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See detailAugmented Reality in Manual Assembly Processes
Kolla, Sri Sudha Vijay Keshav UL; Sanchez, Andre UL; Minoufekr, Meysam UL et al

in Kolla, Sri Sudha Vijay Keshav; Sanchez, Andre; Minoufekr, Meysam (Eds.) et al Augmented Reality in Manual Assembly Processes (2020, September 23)

Augmented Reality (AR) is a novel technology that projects virtual information on the real world environment. With the increased use of Industry 4.0 technologies in manufacturing, AR has gained momentum ... [more ▼]

Augmented Reality (AR) is a novel technology that projects virtual information on the real world environment. With the increased use of Industry 4.0 technologies in manufacturing, AR has gained momentum across various stages of product life cycle. AR can benefit production operators in many manufacturing tasks such as quality inspection, work instructions for manual assembly, maintenance, and in training. This research presents not only a typical architecture of an AR system but also both its software and hardware functions. The architecture is then applied to display virtual assembly instructions in the form of 3D animations on to the real world environment. The chosen assembly task in this research is to assemble a planetary gearbox system. The assembly instructions are displayed on a mobile device targeting a static tracker placed in the assembly environment. [less ▲]

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See detailActive Re-identification Attacks on Periodically Released Dynamic Social Graphs
Chen, Xihui UL; Kepuska, Ema UL; Mauw, Sjouke UL et al

in Chen, Liqun; Li, Ninghui; Liang, Kaitai (Eds.) et al Computer Security - ESORICS 2020 (2020, September 13)

Active re-identification attacks pose a serious threat to privacy-preserving social graph publication. Active attackers create fake accounts to enforce structural patterns that can be used to re-identify ... [more ▼]

Active re-identification attacks pose a serious threat to privacy-preserving social graph publication. Active attackers create fake accounts to enforce structural patterns that can be used to re-identify legitimate users on published anonymised graphs, even without additional background knowledge. So far, this type of attacks has only been studied in the scenario where the inherently dynamic social graph is published once. In this paper, we present the first active re-identification attack in the more realistic scenario where a dynamic social graph is periodically published. Our new attack leverages tempo-structural patterns, created by a dynamic set of sybil nodes, for strengthening the adversary. We evaluate our new attack through a comprehensive set of experiments on real-life and synthetic dynamic social graphs. We show that our new attack substantially outperforms the most effective static active attack in the literature by increasing success probability by at least two times and efficiency by at least 11 times. Moreover, we show that, unlike the static attack, our new attack remains at the same level of efficiency as the publication process advances. Additionally, we conduct a study on the factors that may thwart our new attack, which can help design dynamic graph anonymisation methods displaying a better balance between privacy and utility. [less ▲]

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See detailTowards Privacy Preserving Data Centric Super App
Carvalho Ota, Fernando Kaway UL; Meira, Jorge Augusto UL; Frank, Raphaël UL et al

in Carvalho Ota, Fernando Kaway; Meira, Jorge Augusto; Frank, Raphaël (Eds.) et al 2020 Mediterranean Communication and Computer Networking Conference, Arona 17-19 June 2020 (2020, September 10)

The number of smartphone users recently surpassed the numbers of desktop users on Internet, and opened up countless development challenges and business opportunities. Not only the fact that the majority ... [more ▼]

The number of smartphone users recently surpassed the numbers of desktop users on Internet, and opened up countless development challenges and business opportunities. Not only the fact that the majority of users are connected using their smartphones, but the number of Internet users in general has popularized the massive use of data-driven applications. In this context, the concept of super apps seems to be the next game-changer for the mobile apps industry, and the challenges related to security and privacy are key aspects for keeping user data safe. Thus, by combining different components for provisioning, authentication, membership and others, we propose a novel framework that enables the creation of a super app using privacy by design principles. [less ▲]

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See detailFostering process skills with the educational technology software MathemaTIC in elementary schools
Haas, Ben; Kreis, Yves UL; Lavicza, Zsolt

in Donevska-Todorova, Ana; Faggiano, Eleonora; Trgalova, Jana (Eds.) et al Proceedings of the 10th ERME TOPIC CONFERENCE (ETC10) on Mathematics Education in the Digital Age (MEDA) (2020, September 07)

This study reports the use of automated tutoring and scaffolding implemented in the module “arithmetic word problem” in the educational technology software MathemaTIC in grade 3 (age 8 to 10). We examined ... [more ▼]

This study reports the use of automated tutoring and scaffolding implemented in the module “arithmetic word problem” in the educational technology software MathemaTIC in grade 3 (age 8 to 10). We examined 246 students with access to MathemaTIC and receiving tutoring and scaffolding through a one-to-one learning setting with this technology. The control group (n=226) had access to the same learning tasks and worked with paper-and-pencil without MathemaTIC but with their teachers. Results showed that the experimental group finished with higher outcome scores than the control group. This paper will outline the study and attempts to explain these results. [less ▲]

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See detailAIR: A Light-Weight Yet High-Performance Dataflow Engine based on Asynchronous Iterative Routing
Ellampallil Venugopal, Vinu UL; Theobald, Martin UL; Chaychi, Samira UL et al

in AIR: A Light-Weight Yet High-Performance Dataflow Engine based on Asynchronous Iterative Routing (2020, September 01)

Distributed Stream Processing Engines (DSPEs) are currently among the most emerging topics in data management, with applications ranging from real-time event monitoring to processing complex dataflow ... [more ▼]

Distributed Stream Processing Engines (DSPEs) are currently among the most emerging topics in data management, with applications ranging from real-time event monitoring to processing complex dataflow programs and big data analytics. In this paper, we describe the architecture of our AIR engine, which is designed from scratch in C++ using the Message Passing Interface (MPI), pthreads for multithreading, and is directly deployed on top of a common HPC workload manager such as SLURM. AIR implements a light-weight, dynamic sharding protocol (referred to as “Asynchronous Iterative Routing”), which facilitates a direct and asynchronous communication among all worker nodes and thereby completely avoids any additional communication overhead with a dedicated master node. With its unique design, AIR fills the gap between the prevalent scale-out (but Java-based) architectures like Apache Spark and Flink, on one hand, and recent scale-up (and C++ based) prototypes such as StreamBox and PiCo, on the other hand. Our experiments over various benchmark settings confirm that AIR performs as good as the best scale-up SPEs on a single-node setup, while it outperforms existing scale-out DSPEs in terms of processing latency and sustainable throughput by a factor of up to 15 in a distributed setting. [less ▲]

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See detailAn AI-assisted Approach for Checking the Completeness of Privacy Policies Against GDPR
Torre, Damiano UL; Abualhaija, Sallam UL; Sabetzadeh, Mehrdad UL et al

in in Proceedings of the 28th IEEE International Requirements Engineering Conference (RE’20) (2020, September)

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See detailTrace-Checking Signal-based Temporal Properties: A Model-Driven Approach
Boufaied, Chaima UL; Menghi, Claudio UL; Bianculli, Domenico UL et al

in Proceedings of the 35th IEEE/ACM International Conference on Automated Software Engineering (ASE ’20) (2020, September)

Signal-based temporal properties (SBTPs) characterize the behavior of a system when its inputs and outputs are signals over time; they are very common for the requirements specification of cyber-physical ... [more ▼]

Signal-based temporal properties (SBTPs) characterize the behavior of a system when its inputs and outputs are signals over time; they are very common for the requirements specification of cyber-physical systems. Although there exist several specification languages for expressing SBTPs, such languages either do not easily allow the specification of important types of properties (such as spike or oscillatory behaviors), or are not supported by (efficient) trace-checking procedures. In this paper, we propose SB-TemPsy, a novel model-driven trace-checking approach for SBTPs. SB-TemPsy provides (i) SB-TemPsy-DSL, a domain-specific language that allows the specification of SBTPs covering the most frequent requirement types in cyber-physical systems, and (ii) SB-TemPsy-Check, an efficient, model-driven trace-checking procedure. This procedure reduces the problem of checking an SB-TemPsy-DSL property over an execution trace to the problem of evaluating an Object Constraint Language constraint on a model of the execution trace. We evaluated our contributions by assessing the expressiveness of SB-TemPsy-DSL and the applicability of SB-TemPsy-Check using a representative industrial case study in the satellite domain. SB-TemPsy-DSL could express 97% of the requirements of our case study and SB-TemPsy-Check yielded a trace-checking verdict in 87% of the cases, with an average checking time of 48.7 s. From a practical standpoint and compared to state-of-the-art alternatives, our approach strikes a better trade-off between expressiveness and performance as it supports a large set of property types that can be checked, in most cases, within practical time limits. [less ▲]

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See detailDeepNDN: Opportunistic Data Replication and Caching in Support of Vehicular Named Data
Manzo, Gaetano; Kalogeiton, Eirini; di Maio, Antonio UL et al

in 21st IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM) (2020, September)

Although many target applications in VANETs are information-centric, the performance of Named Data Networking (NDN) in vehicular ad-hoc networks is severely hampered by persistent network partitioning ... [more ▼]

Although many target applications in VANETs are information-centric, the performance of Named Data Networking (NDN) in vehicular ad-hoc networks is severely hampered by persistent network partitioning, typical of many vehicular scenarios. Existing approaches try to address this issue by relying on opportunistic communications. However, they leave open the crucial issue of how to guarantee content persistence and tight QoS levels while optimizing the resource utilization in the vehicular environment. In this work we propose DeepNDN, a communication scheme based on the joint application of NDN and of probabilistic spatial content caching, which enables content retrieval in fragmented and dynamic network topologies with tight delay constraints. We present a data-based approach to DeepNDN management, based on locally modulating content replication and delivery in order to achieve a target hit ratio in a resource-efficient manner. Our management algorithm employs a Convolutional Neural Network (CNN) architecture for effectively capturing the complex relations between spatio-temporal patterns of mobility and content requests and DeepNDN performance. Its numerical assessment in realistic, measurement-based scenarios suggest that our management approach achieves its target set goals while outperforming a set of reference schemes. [less ▲]

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See detailForest SaVR – A Virtual-Reality Application to Raise Awareness of Deforestation
Botev, Jean UL; Viegas Milani, Adriano

in Proceedings of the 17th GI VR/AR Workshop (VAR) (2020, September)

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See detailSparse Gaussian Process Based On Hat Basis Functions
Fang, W.; Li, H.; Huang, Hui UL et al

in 2020 International Conference on Electrical, Communication, and Computer Engineering (ICECCE) (2020, August 28)

Gaussian process is a popular non-parametric Bayesian methodology for modeling the regression problem, which is completely determined by its mean and covariance function. Nevertheless, this method still ... [more ▼]

Gaussian process is a popular non-parametric Bayesian methodology for modeling the regression problem, which is completely determined by its mean and covariance function. Nevertheless, this method still has two major disadvantages: it is difficult to handle large datasets and may not meet inequality constraints in specific problems. These two issues have been addressed by the so-called sparse Gaussian process and constrained Gaussian process in recent years. In this paper, to reduce the overall computational complexity in the exact Gaussian process, we propose a new sparse Gaussian process method to solve the unconstrained regression problem. The idea is inspired by the constrained Gaussian process method. The critical point of our method is that we introduce the hat basis function, which is mentioned in the constrained Gaussian process, and modify its definition according to the range of training or test data. It turns out that this method belongs to the spectral approximation methods. Similar to the exact Gaussian process and Gaussian process with Fully Independent Training Conditional approximation, our method obtains satisfactory approximate results on analytical functions or open-source datasets. [less ▲]

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See detailA Data Science Approach for Honeypot Detection in Ethereum
Camino, Ramiro Daniel UL; Ferreira Torres, Christof UL; Baden, Mathis UL et al

in 2020 IEEE International Conference on Blockchain and Cryptocurrency (ICBC) (2020, August 17)

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See detailAn Algebraic Formulation of the Division Property: Revisiting Degree Evaluations, Cube Attacks, and Key-Independent Sums
Hu, Kai; Sun, Siwei; Wang, Meiqin et al

in 26th Annual International Conference on the Theory and Application of Cryptology and Information Security- ASIACRYPT 2020 (2020, August 16)

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See detailAn Algebraic Attack on Ciphers with Low-Degree Round Functions: Application to Full MiMC
Eichlseder, Maria; Grassi, Lorenzo; Lüftenegger, Reinhard et al

in 26th Annual International Conference on the Theory and Application of Cryptology and Information Security - ASIACRYPT 2020 (2020, August 16)

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See detailA Polynomial-Time Algorithm for Solving the Hidden Subset Sum Problem
Coron, Jean-Sébastien UL; Gini, Agnese UL

in Advances in Cryptology -- CRYPTO 2020 (2020, August 10)

At Crypto '99, Nguyen and Stern described a lattice based algorithm for solving the hidden subset sum problem, a variant of the classical subset sum problem where the n weights are also hidden. While the ... [more ▼]

At Crypto '99, Nguyen and Stern described a lattice based algorithm for solving the hidden subset sum problem, a variant of the classical subset sum problem where the n weights are also hidden. While the Nguyen-Stern algorithm works quite well in practice for moderate values of n, we argue that its complexity is actually exponential in n; namely in the final step one must recover a very short basis of a n-dimensional lattice, which takes exponential-time in n, as one must apply BKZ reduction with increasingly large block-sizes. [less ▲]

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See detailThe Higher-Order Prover Leo-III (Highlight paper)
Steen, Alexander UL; Benzmüller, Christoph UL

in Proceedings of the 24th European Conference on Artificial Intelligence (2020, August)

Leo-III is an effective automated theorem prover for extensional type theory with Henkin semantics. It is based on an extensional higher-order paramodulation calculus and supports reasoning in monomorphic ... [more ▼]

Leo-III is an effective automated theorem prover for extensional type theory with Henkin semantics. It is based on an extensional higher-order paramodulation calculus and supports reasoning in monomorphic and rank-1 polymorphic first-order and higher-order logics. Leo-III also automates various non-classical logics, including almost every normal higher-order modal logic. [less ▲]

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See detailEfficient AGCD-Based Homomorphic Encryption for Matrix and Vector Arithmetic
Lima Pereira, Hilder Vitor UL

in Applied Cryptography and Network Security (2020, August)

We propose a leveled homomorphic encryption scheme based on the Approximate Greatest Common Divisor (AGCD) problem that operates natively on vectors and matrices. To overcome the limitation of large ... [more ▼]

We propose a leveled homomorphic encryption scheme based on the Approximate Greatest Common Divisor (AGCD) problem that operates natively on vectors and matrices. To overcome the limitation of large ciphertext expansion that is typical in AGCD-based schemes, we randomize the ciphertexts with a hidden matrix, which allows us to choose smaller parameters. To be able to efficiently evaluate circuits with large multiplicative depth, we use a decomposition technique à la GSW. The running times and ciphertext sizes are practical: for instance, for 100 bits of security, we can perform a sequence of 128 homomorphic products between 128-dimensional vectors and 128×128 matrices in less than one second. We show how to use our scheme to homomorphically evaluate nondeterministic finite automata and also a Naïve Bayes Classifier. [less ▲]

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See detailSelf-Integration in Mediated-Reality Systems: a Socio-Technical Perspective
Botev, Jean UL

in Proceedings of the 1st IEEE International Conference on Autonomic Computing and Self-Organizing Systems (ACSOS) (2020, August)

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See detailOne-Bit Quantized Constructive Interference Based Precoding for Massive Multiuser MIMO Downlink
Haqiqatnejad, Alireza UL; Kayhan, Farbod UL; Shahbazpanahi, Shahram UL et al

in One-Bit Quantized Constructive Interference Based Precoding for Massive Multiuser MIMO Downlink (2020, July 27)

We propose a one-bit symbol-level precoding method for massive multiuser multiple-input multiple-output (MU-MIMO) downlink systems using the idea of constructive interference (CI). In particular, we adopt ... [more ▼]

We propose a one-bit symbol-level precoding method for massive multiuser multiple-input multiple-output (MU-MIMO) downlink systems using the idea of constructive interference (CI). In particular, we adopt a max-min fair design criterion which aims to maximize the minimum instantaneous received signal-to-noise ratio (SNR) among the user equipments (UEs), while ensuring a CI constraint for each UE and under the restriction that the output of the precoder is a vector of binary elements. This design problem is an NP-hard binary quadratic programming due to the one-bit constraints on the elements of the precoder’s output vector, and hence, is difficult to solve. In this paper, we tackle this difficulty by reformulating the problem, in several steps, into an equivalent continuous-domain biconvex form. Our final biconvex reformulation is obtained via an exact penalty approach and can efficiently be solved using a standard block coordinate ascent algorithm. We show through simulation results that the proposed design outperforms the existing schemes in terms of (uncoded) bit error rate. It is further shown via numerical analysis that our solution algorithm is computationally-efficient as it needs only a few tens of iterations to converge in most practical scenarios. [less ▲]

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See detailAutomated Repair of Feature Interaction Failures in Automated Driving Systems
Ben Abdessalem, Raja; Panichella, Annibale; Nejati, Shiva UL et al

in Proceedings of the 29th ACM SIGSOFT International Symposium on Software Testing and Analysis (ISSTA 2020) (2020, July)

In the past years, several automated repair strategies have been proposed to fix bugs in individual software programs without any human intervention. There has been, however, little work on how automated ... [more ▼]

In the past years, several automated repair strategies have been proposed to fix bugs in individual software programs without any human intervention. There has been, however, little work on how automated repair techniques can resolve failures that arise at the system-level and are caused by undesired interactions among different system components or functions. Feature interaction failures are common in complex systems such as autonomous cars that are typically built as a composition of independent features (i.e., units of functionality). In this paper, we propose a repair technique to automatically resolve undesired feature interaction failures in automated driving systems (ADS) that lead to the violation of system safety requirements. Our repair strategy achieves its goal by (1) localizing faults spanning several lines of code, (2) simultaneously resolving multiple interaction failures caused by independent faults, (3) scaling repair strategies from the unit-level to the system-level, and (4) resolving failures based on their order of severity. We have evaluated our approach using two industrial ADS containing four features. Our results show that our repair strategy resolves the undesired interaction failures in these two systems in less than 16h and outperforms existing automated repair techniques. [less ▲]

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See detailChallenges Towards Production-Ready Explainable Machine Learning
Veiber, Lisa UL; Allix, Kevin UL; Arslan, Yusuf UL et al

in Veiber, Lisa; Allix, Kevin; Arslan, Yusuf (Eds.) et al Proceedings of the 2020 USENIX Conference on Operational Machine Learning (OpML 20) (2020, July)

Machine Learning (ML) is increasingly prominent in or- ganizations. While those algorithms can provide near perfect accuracy, their decision-making process remains opaque. In a context of accelerating ... [more ▼]

Machine Learning (ML) is increasingly prominent in or- ganizations. While those algorithms can provide near perfect accuracy, their decision-making process remains opaque. In a context of accelerating regulation in Artificial Intelligence (AI) and deepening user awareness, explainability has become a priority notably in critical healthcare and financial environ- ments. The various frameworks developed often overlook their integration into operational applications as discovered with our industrial partner. In this paper, explainability in ML and its relevance to our industrial partner is presented. We then dis- cuss the main challenges to the integration of ex- plainability frameworks in production we have faced. Finally, we provide recommendations given those challenges. [less ▲]

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See detailJoint User Scheduling, and Precoding for Multicast Spectral Efficiency in Multigroup Multicast Systems
Bandi, Ashok UL; Mysore Rama Rao, Bhavani Shankar UL; Chatzinotas, Symeon UL et al

in International conference on signal processing and communications (SPCOM) (2020, July)

This paper studies the joint design of user scheduling and precoding for the maximization of spectral efficiency (SE) for a multigroup multicast scenario in multiuser MISO downlink channels. Noticing that ... [more ▼]

This paper studies the joint design of user scheduling and precoding for the maximization of spectral efficiency (SE) for a multigroup multicast scenario in multiuser MISO downlink channels. Noticing that the existing definition of SE fails to account for group sizes, a new metric called multicast spectral efficiency (MC-SE) is proposed. In this context, the joint design is considered for the maximization of MC-SE. Firstly, with the help of binary scheduling variables, the joint design problem is formulated as a mixed-integer non-linear programming problem such that it facilitates the joint update of scheduling and precoding variables. Further, useful reformulations are proposed to reveal the hidden difference-of-convex/concave structure of the problem. Thereafter, we propose a convex-concave procedure based iterative algorithm with convergence guarantees to a stationary point. Finally, we compare different aspects namely MC-SE, SE and number of scheduled users through Monte-Carlo simulations. [less ▲]

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See detailUML Consistency Rules:a Case Study with Open-Source UML Models
Torre, Damiano UL; Labiche, Yvan; Genero, Marcela et al

in Proceedings of the 8th International Conference on Formal Methods in Software Engineering (2020, July)

UML models are standard artifacts used by software engineers for designing software. As software is designed, different UML diagram types (e.g., class diagrams and sequence diagrams) are produced by ... [more ▼]

UML models are standard artifacts used by software engineers for designing software. As software is designed, different UML diagram types (e.g., class diagrams and sequence diagrams) are produced by software designers. Since the various UML diagram types describe different aspects of a software system, they are not independent but strongly depend on each other, hence they must be consistent. Inconsistencies cause faults in the final software systems. It is, therefore, paramount that they get detected, analyzed, and fixed. Consistency rules are a useful tool proposed in the literature to detect inconsistencies. They categorize constraints that help in identifying inconsistencies when violated. This case study aims at collecting and analyzing UML models with OCL consistency rules proposed in the literature and at promoting the development of a reference benchmark that can be reused by the (FM-)research community. We collected 33 UML consistency rules and 206 different UML diagrams contained in 34 open-source UML models presented in the literature. We propose an FM-based encoding of the consistency rules in OCL. This encoding allows analyzing whether the consistency rules are satisfied or violated within the 34 UML models. To assess the proposed benchmark, we analyzed how the UML models, consistency rules, diagram types contained in the benchmark help in assessing the consistency of UML models, and the consistency of diagrams across the different software development phases. Our results show that the considered UML models and consistency rules allowed identifying 2731 inconsistencies and that those inconsistencies refer to different software development phases. We concluded that the considered UML models and consistency rules could be considered as an initial benchmark that can be further extended by the research community. [less ▲]

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See detailDeveloping an Interactive Tabletop Mediated Activity to Induce Collaboration by Implementing Design Considerations Based on Cooperative Learning Principles
Sunnen, Patrick UL; Arend, Béatrice UL; Heuser, Svenja UL et al

in Stephanidis, Constantine; Antona, Margherita (Eds.) HCI International 2020 - Posters (2020, July)

Constructive collaboration can be a difficult matter. For this reason, we are implementing and studying an interactive-tabletop-mediated activity that aims at inducing collaboration among participants ... [more ▼]

Constructive collaboration can be a difficult matter. For this reason, we are implementing and studying an interactive-tabletop-mediated activity that aims at inducing collaboration among participants. The resulting activity ‘Orbitia’ is designed as a serious game. Participants are asked to act as a space- mining crew, which has to collect minerals with a rover and rely on a camera- drone for reconnaissance, while keeping the rover out of harm and managing limited resources. In this paper we provide an account of how we designed Orbitia’s pedagogical structuring by relying on the Johnsons’ cooperative learning approach whose fundamental concept is “positive interdependence”. More particularly, we show how we worked on resource, role and task inter- dependence to design three collaboration-inducing ‘flagship’ devices: the rover- steering-device (RSD), the item-locating-device (ILD) and the responsibility- activating-device (RAD). [less ▲]

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See detailImmersive Telepresence Framework for Remote Educational Scenarios
Botev, Jean UL; Rodríguez Lera, Francisco J.

in Proceedings of the 22nd International Conference on Human-Computer Interaction (HCI International) (2020, July)

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See detailPolitiques de synchronisation dans les systèmes multi-agents distribués parallèles
Rousset, Alban UL; Breugnot, Paul; Herrmann, Bénédicte et al

in Rousset, Alban (Ed.) Politiques de synchronisation dans les systèmes multi-agents distribués parallèles (2020, June 29)

Among simulation or modelisation methods, multi-agent systems are an interesting candidate to simulate complex systems. As the size of the model's increases, the use of parallel multi-agent systems is ... [more ▼]

Among simulation or modelisation methods, multi-agent systems are an interesting candidate to simulate complex systems. As the size of the model's increases, the use of parallel multi-agent systems is mandatory but comes with many issues. In this article, we are interested in the impact of synchronization on models design and on their execution. We highlight synchronization problems through model instances then we experimentally analyze the impact of synchronization on large scale test cases. [less ▲]

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See detailSupporting Citizens’ Political Decision-Making Using Information Visualisation
Graf, Vanessa; Graf-Drasch, Valerie; Tiefenbeck, Verena et al

in Proceedings of the 28th European Conference on Information Systems (ECIS) (2020, June 17)

Individual decision-making is a complex process. If carried out by individual citizens in the context of politically relevant decisions, serious consequences at all levels of a society might occur. That ... [more ▼]

Individual decision-making is a complex process. If carried out by individual citizens in the context of politically relevant decisions, serious consequences at all levels of a society might occur. That is why these decisions need to be made with care and preferably on a broad set of information to reflect citizens’ true preferences. However, due to limited attention, citizens often consider only salient aspects in their decision-making. To mitigate unwanted consequences following therefrom, citizens are in dire need of decision-support. We address this need by developing an Information Systems (IS) tool. Being based on information visualisation, our tool supports citizens by providing instant feedback. To ensure a meaningful engagement, the IS tool is designed according to gamification principles. A first instantiation in the context of renewable energy acceptance in Germany yields three key findings: First, we find indications that young, urban, and environmentally aware citizens are willing to accept a high percentage of renewable wind energy. Second, we find that the tool influences citizens’ decision-making. Third, we find citizens to update, however not completely turn over their preferred level of renewable wind energy after interaction with the tool. This holds true across different cross-sections of the population. [less ▲]

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See detailToward Metacognitive Radars: Concept and Applications
Mishra, K. V.; Shankar, M. R. B.; Ottersten, Björn UL

in 2020 IEEE International Radar Conference (RADAR), Toward Metacognitive Radars: Concept and Applications (2020, June 11)

We introduce a metacognitive approach to optimize the radar performance for a dynamic wireless channel. Similar to the origin of the cognitive radar in the neurobiological concept of cognition ... [more ▼]

We introduce a metacognitive approach to optimize the radar performance for a dynamic wireless channel. Similar to the origin of the cognitive radar in the neurobiological concept of cognition, metacognition also originates from neurobiological research on problem-solving and learning. Broadly defined as the process of learning to learn, metacognition improves the application of knowledge in domains beyond the immediate context in which it was learned. We describe basic features of a metacognitive radar and then illustrate its application with some examples such as antenna selection and resource sharing between radar and communications. Unlike previous works in communications that only focus on combining several existing algorithms to form a metacognitive radio, we also show the transfer of knowledge in a metacognitive radar. A metacognitive radar improves performance over individual cognitive radar algorithms, especially when both the channel and transmit/receive hardware are changed. [less ▲]

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See detailDiscovering Everyday Mathematical Situations Outside the Classroom with MathCityMap and GeoGebra 3D
Lavicza, Zsolt; Haas, Ben; Kreis, Yves UL

in Ludwig, Matthias; Jablonski, Simone; Caldeira, Amélia (Eds.) et al Research on Outdoor STEM Education in the digiTal Age: Proceedings of the ROSETA Online Conference in June 2020 (2020, June 10)

In elementary school, teaching and learning activities aim to develop, among others, students’ skills to acquire deeper understanding of their living environments. There are numerous opportunities for ... [more ▼]

In elementary school, teaching and learning activities aim to develop, among others, students’ skills to acquire deeper understanding of their living environments. There are numerous opportunities for students to recognize forms, shapes, and mathematical connections in everyday situations. These everyday situations can be simulated in classrooms; however, educational technologies offer new approaches to extend classroom activities, teachers can simulate and design shapes through Augmented Reality and 3D printing within or beyond the classroom. To stimulate students’ everyday mathematical connections utilizing these technologies could assist in developing activities outside the classroom in urban or in natural environments. Through this approach students could utilize or enhance their mathematical and technical skills within their usual living environments. Utilising educational software such as MathCityMap, GeoGebra 3D Calculator, and other 3D modelling software we developed examples of tasks that could offer easy transitions from in- to out-side of classrooms. In this paper, we will describe learning and teaching aims of these tasks and outline further research and development directions to broaden opportunities to develop students’ mathematical, design and modelling skills. [less ▲]

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See detailToward an SDN-based Data Collection Scheme for Vehicular Fog Computing
Boualouache, Abdelwahab UL; Soua, Ridha UL; Engel, Thomas UL

in IEEE International Conference on Communications ICC'2020 (2020, June 07)

With the integration of fog networks and vehicular networks, Vehicular Fog Computing (VFC) is a promising paradigm to efficiently collect data for improving safety, mobility, and driver experience during ... [more ▼]

With the integration of fog networks and vehicular networks, Vehicular Fog Computing (VFC) is a promising paradigm to efficiently collect data for improving safety, mobility, and driver experience during journeys. To this end, we exploit the Software-Defined Networking (SDN) paradigm to propose a fully-programmable, self-configurable, and context-aware data collection scheme for VFC. This scheme leverages a stochastic model to dynamically estimate the number of fog stations to be deployed. Our simulation results demonstrate that our proposed scheme provides lower latency and higher resiliency compared to classical data collection schemes. [less ▲]

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See detailA Novel Heap-based Pilot Assignment for Full Duplex Cell-Free Massive MIMO with Zero-Forcing
Nguyen, Van Hieu; Nguyen, van Dinh UL; Dobre, Octavia A. et al

in IEEE International Conference on Communications (2020, June 07)

This paper investigates the combined benefits of full-duplex (FD) and cell-free massive multiple-input multipleoutput (CF-mMIMO), where a large number of distributed access points (APs) having FD ... [more ▼]

This paper investigates the combined benefits of full-duplex (FD) and cell-free massive multiple-input multipleoutput (CF-mMIMO), where a large number of distributed access points (APs) having FD capability simultaneously serve numerous uplink and downlink user equipments (UEs) on the same time-frequency resources. To enable the incorporation of FD technology in CF-mMIMO systems, we propose a novel heapbased pilot assignment algorithm, which not only can mitigate the effects of pilot contamination but also reduce the involved computational complexity. Then, we formulate a robust design problem for spectral efficiency (SE) maximization in which the power control and AP-UE association are jointly optimized, resulting in a difficult mixed-integer nonconvex programming. To solve this problem, we derive a more tractable problem before developing a very simple iterative algorithm based on inner approximation method with polynomial computational complexity. Numerical results show that our proposed methods with realistic parameters significantly outperform the existing approaches in terms of the quality of channel estimate and SE. [less ▲]

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See detailDebugging Inputs
Kirschner, Lukas; Soremekun, Ezekiel UL; Zeller, Andreas

in Proceedings of the ACM/IEEE 42nd International Conference on Software Engineering (2020, June)

When a program fails to process an input, it need not be the program code that is at fault. It can also be that the input data is faulty, for instance as result of data corruption. To get the data ... [more ▼]

When a program fails to process an input, it need not be the program code that is at fault. It can also be that the input data is faulty, for instance as result of data corruption. To get the data processed, one then has to debug the input data—that is, (1) identify which parts of the input data prevent processing, and (2) recover as much of the (valuable) input data as possible. In this paper, we present a general-purpose algorithm called ddmax that addresses these problems automatically. Through experiments, ddmax maximizes the subset of the input that can still be processed by the program, thus recovering and repairing as much data as possible; the difference between the original failing input and the “maximized” passing input includes all input fragments that could not be processed. To the best of our knowledge, ddmax is the first approach that fixes faults in the input data without requiring program analysis. In our evaluation, ddmax repaired about 69% of input files and recovered about 78% of data within one minute per input. [less ▲]

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See detailPerceptive Packet Scheduling for Carrier Aggregation in Satellite Communication Systems
Al-Hraishawi, Hayder UL; Maturo, Nicola UL; Lagunas, Eva UL et al

in IEEE International Conference on Communications, June 2020. (2020, June)

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See detailPredicting near-optimal skin distance in Verlet buffer approach for Discrete Element Method
Mainassara Chekaraou, Abdoul Wahid UL; Besseron, Xavier UL; Rousset, Alban UL et al

in 10th IEEE Workshop on Parallel / Distributed Combinatorics and Optimization (2020, June)

The Verlet list method is a well-known bookkeeping technique of the interaction list used both in Molecular Dynamic (MD) and Discrete Element Method (DEM). The Verlet buffer technique is an enhancement of ... [more ▼]

The Verlet list method is a well-known bookkeeping technique of the interaction list used both in Molecular Dynamic (MD) and Discrete Element Method (DEM). The Verlet buffer technique is an enhancement of the Verlet list that consists of extending the interaction radius of each particle by an extra margin to take into account more particles in the interaction list. The extra margin is based on the local flow regime of each particle to account for the different flow regimes that can coexist in the domain. However, the choice of the near-optimal extra margin (which ensures the best performance) for each particle and the related parameters remains unexplored in DEM unlike in MD. In this study, we demonstrate that the near-optimal extra margin can fairly be characterized by four parameters that describe each particle local flow regime: the particle velocity, the ratio of the containing cell size to particle size, the containing cell solid fraction, and the total number of particles in the system. For this purpose, we model the near-optimal extra margin as a function of these parameters using a quadratic polynomial function. We use the DAKOTA SOFTWARE to carry out the Design and Analysis of Computer Experiments (DACE) and the sampling of the parameters for the simulations. For a given instance of the set of parameters, a global optimization method is considered to find the near-optimal extra margin. The latter is required for the construction of the quadratic polynomial model. The numerous simulations generated by the sampling of the parameter were performed on a High-Performance Computing (HPC) environment granting parallel and concurrent executions. This work provides a better understanding of the Verlet buffer method in DEM simulations by analyzing its performances and behavior in various configurations. The near-optimal extra margin can reasonably be predicted by two out of the four chosen parameters using the quadratic polynomial model. This model has been integrated into XDEM in order to automatically choose the extra margin without any input from the user. Evaluations on real industrial-level test cases show up to a 26% reduction of the execution time. [less ▲]

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See detailAn Integrated Teleoperation Assistance System for Collision Avoidance of High-speed UAVs in Complex Environments
Wang, Min UL; Voos, Holger UL

in 17th International Conference on Ubiquitous Robots (UR), Kyoto 22-26 June 2020 (2020, June)

UAV teleoperation is a demanding task, especially for amateur operators who wish to successfully accomplish their mission without collision. In this work we present an integrated 2D LIDAR based Sense-and ... [more ▼]

UAV teleoperation is a demanding task, especially for amateur operators who wish to successfully accomplish their mission without collision. In this work we present an integrated 2D LIDAR based Sense-and-Avoid system which actively assists unskilled human operator in obstacle avoidance, so that the operator can focus on higher-level decisions and global objectives in UAV applications such as search and rescue, farming etc. Specifically, with our perception-assistive vehicle control design, novel adaptive virtual cushion force field (AVCFF) based avoidance strategy, and integrated sensing solution, the proposed UAV teleoperation assistance system is capable of obstacle detection and tracking, as well as automatic avoidance in complex environment where both static and dynamic objects are present. The proposed system is constructed on the basis of Hector Quadrotor open source framework [1], and its effectiveness is demonstrated and validated on a realistic simulated UAV platform in Gazebo simulations where the UAV is operated at a high speed. [less ▲]

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See detailEnhancing CoAP Group Communication to Support mMTC Over Satellite Networks
Soua, Ridha UL; Palattella, Maria Rita UL; Stemper, André UL et al

in IEEE International Conference on Communications (ICC) (2020, June)

Massive MTC (mMTC) is one of the application scenarios that upcoming 5G networks are expected to support. Satellites come into play in mMTC to complement and extend terrestrial networks in under-served ... [more ▼]

Massive MTC (mMTC) is one of the application scenarios that upcoming 5G networks are expected to support. Satellites come into play in mMTC to complement and extend terrestrial networks in under-served areas, where several services can benefit from the adoption of a group communication model. The IETF has specifically standardized the usage of CoAP group communication. However, CoAP responses are still sent in unicast from each single CoAP server to the CoAP client, which results in a substantial traffic load. Such problem becomes more severe in integrated IoT-Satellite networks given the limited bandwidth of the satellite return channel and the large number of IoT devices in a mMTC scenario. To reduce network traffic overhead in group communication and improve the network responsiveness, this paper proposes an aggregation scheme for the CoAP group communication in combination with Observer pattern and proxying. Results obtained by using the openSAND emulator and CoAPthon library corroborate the merit of our optimization in terms of overhead reduction and delay. [less ▲]

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See detailGOING DEEPER WITH NEURAL NETWORKS WITHOUT SKIP CONNECTIONS
Oyedotun, Oyebade UL; Shabayek, Abd El Rahman UL; Aouada, Djamila UL et al

in IEEE International Conference on Image Processing (ICIP 2020), Abu Dhabi, UAE, Oct 25–28, 2020 (2020, May 30)

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See detailDeep Rainrate Estimation from Highly Attenuated Downlink Signals of Ground-Based Communications Satellite Terminals
Mishra, K. V.; R., B. S. M.; Ottersten, Björn UL

in ICASSP 2020 - 2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), Deep Rainrate Estimation from Highly Attenuated Downlink Signals of Ground-Based Communications Satellite Terminals (2020, May 14)

While the use of weather radars to continuously monitor the spatiotemporal dynamics of precipitation has grown in recent years, these systems are expensive and sparsely deployed across the world. In this ... [more ▼]

While the use of weather radars to continuously monitor the spatiotemporal dynamics of precipitation has grown in recent years, these systems are expensive and sparsely deployed across the world. In this context, densely located ground-based terminals for interactive satellite services have the potential for dual-use as weather sensors because they measure rain-attenuated power of the downlink signal. Although in the millimeter-wave regime, the rain rate has almost a linear relationship with specific attenuation, lack of other weather radar observables at satellite terminals imposes a daunting task of extracting rainfall rate from these highly attenuated signals. We address this problem by designing a deep convolutional neural network (CNN) that learns the relationship between the signal attenuation and rainfall rate observed by weather radars and rain gauges at a given location. During the prediction stage, the CNN accepts downlink attenuation as input and classifies the rain intensity which is then used to apply an appropriate rainfall estimator. Our experiments with real data show that, despite severe attenuation, CNN-based downlink rainfall accumulations closely follow the nearest C-band German weather service Deutscher Wetterdienst (DWD) radar. [less ▲]

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