References of "Scientific congresses, symposiums and conference proceedings"
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See detailInequalities in teacher reports on students’ inclusion at school
Zurbriggen, Carmen UL; Nusser, Lena; Schmitt, Monja

Scientific Conference (2020, November)

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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 detailThe patients’ perspective on access to and use of Personal Health Records
Paccoud, Ivana UL; Baumann, Michèle UL; Le Bihan, Etienne UL et al

Scientific Conference (2020, October 29)

We present the patients' perspective regarding the use of Personal Health Records, and give insights on patients' characteristics, such as socioeconomic and behavioural factors, that are associated with ... [more ▼]

We present the patients' perspective regarding the use of Personal Health Records, and give insights on patients' characteristics, such as socioeconomic and behavioural factors, that are associated with the access to and use of Personal Health Records. The findings come from the INTERREG APPS project that investigated preferences for and intention to use Personal Health Records in four cross-border regions, in Lorraine/France, Luxembourg, Rhineland-Palatinate and Saarland/Germany, and Wallonia/Belgium. [less ▲]

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See detailLarge scale realistic virtual environments for lunar robotics testing using real-time computer games engines
Ludivig, Philippe UL; Voos, Holger UL; Lamamy, Julien

Poster (2020, October 23)

Virtual simulation environments are a great tool for testing different rover systems before they are sent to the moon. They allow for perfect repeatability and give abetter idea how specific parameters ... [more ▼]

Virtual simulation environments are a great tool for testing different rover systems before they are sent to the moon. They allow for perfect repeatability and give abetter idea how specific parameters can impact the overall system. Most current simulators however suffer from low visual fidelity which is problematic for testing the vision sensors needed for autonomous navigation.Additionally, due to technical and practical limitations, most simulations are limited in environment scale. This is problematic for long range navigation testing needed for missions such as the mars sample fetch rover[1]. In order to solve both issues, we turn towards a popular computer game engine,Unreal Engine 4. It allows for larger environments than what is currently possible in robotics simulators such as Gazebo[2]or V-rep[3]. It also addresses the visual fidelity with a range of tools including real-time ray-tracing.The tradeoff is a low physics fidelity, which can be an issue when testing wheel-soil interaction. For our use-case we focus primarily on perception systems needed for rover navigation, such as mono and stereo camera systems, where visual fidelity is more important. [less ▲]

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See detailABSOLUTE LOCALIZATION FOR SURFACE ROBOTICS IN GPS-DENIED ENVIRONMENTS USING A NEURAL NETWORK.
Wu, Ben; Ludivig, Philippe UL; Potter, Ross et al

Poster (2020, October 23)

Accurate localization in surface robotics is essential for navigation, path planning, and science objectives. On Earth, absolute localization can be readily achieved via satellite navigation (e.g., GPS ... [more ▼]

Accurate localization in surface robotics is essential for navigation, path planning, and science objectives. On Earth, absolute localization can be readily achieved via satellite navigation (e.g., GPS). For other planetary bodies such as the Moon or Mars, however, such systems are unavailable. Current methods for absolute localization of planetary rovers rely on time- and labor-intensive human visual matching of surface perspective features with satellite images. Relative localization also accumulates errors over time, with different methods estimating dissimilar locations (e.g., [1]). Thus, an absolute localization method that can quickly, automatically, and accurately reduce the position search space is of great benefit to future planetary exploration missions. This project [2] presents a new approach to localizing planetary rovers: training an artificial neural network to match surfaceperspective imagery to corresponding satellite maps. [less ▲]

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See detailTESTING ENVIRONMENTS FOR LUNAR SURFACE PERCEPTION SYSTEMS; COMBINING INDOOR FACILITIES, VIRTUAL ENVIRONMENTS AND ANALOGUE FIELD TESTS.
Ludivig, Philippe UL; Olivares Mendez, Miguel Angel UL; Calzada Diaz, Abigail et al

Scientific Conference (2020, October 21)

This paper describes the different approaches which can be used to test vision systems for operations on robotic lunar surface missions. We investigate validating systems in virtual environments, lab ... [more ▼]

This paper describes the different approaches which can be used to test vision systems for operations on robotic lunar surface missions. We investigate validating systems in virtual environments, lab environments and analogue outdoor environments and demonstrate that a combination of all three approach-es is needed to sufficiently test systems for the lunar surface. [less ▲]

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See detailAge differences in physical activity with regard to motivational regulation types in youth sport
Hutmacher, Djenna UL; Eckelt, Melanie UL; Bund, Andreas UL et al

Poster (2020, October 21)

A decline in physical activity (PA) with increasing age has been reported consistently (e.g., Bassett et al., 2015). In this sense, physical education (PE) has become a key issue to intercept youth, in ... [more ▼]

A decline in physical activity (PA) with increasing age has been reported consistently (e.g., Bassett et al., 2015). In this sense, physical education (PE) has become a key issue to intercept youth, in order to promote PA at an early age. To reduce the research gap with regard to the underlying mechanisms of this decline, we investigated the role of age for motivational aspects of the self-determination theory (Deci & Ryan, 2000) concerning scholars’ basic needs (competence, relatedness, autonomy; Vlachopoulos, Ntoumanis, & Smith, 2010), PE teacher need-support (Standage, Duda, & Ntoumanis, 2005), and different motivational regulation types during PE (Vlachopoulos, Katartzi, Kontou, Moustaka, & Goudas, 2011). As a transfer of motivational regulation types from PE towards a leisure-time context has been found (Hagger & Chatzisarantis, 2016), this study furthermore analyzed the role of age in an out-of-school PA environment (Markland & Tobin, 2004). In total, 1889 scholars (50.9% males; 10 to 23 years) from 14 different schools participated in the study. Consistent with previous findings, the self-reported PA decreased with age. Further regression analysis revealed that the feeling of being competent during PE decreased with age, while the feeling of being autonomous increased. No differences regarding age and need-support during PE were found. Regarding the motivational regulation types during PE, the internal motivation decreased with age, while the external motivation increased. Concerning the leisure-time context, all motivational regulation types towards PA decreased with age. SEM-Models confirmed the significant relationship between motivational regulation types from PE to a leisure-time context. Overall, results suggest that a decrease of PA with age might be related to a decrease of internal motivation forms as years go by. Implications for promoting beneficial motivational regulation types during PE related to the age of scholars will be displayed. [less ▲]

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See detailTraffic Simulator for Multibeam Satellite Communication Systems
Al-Hraishawi, Hayder UL; Lagunas, Eva UL; Chatzinotas, Symeon UL

Scientific Conference (2020, October 20)

Assume that a multibeam satellite communication system is designed from scratch to serve a particular area with maximal resource utilization and to satisfactorily accommodate the expected traffic demand ... [more ▼]

Assume that a multibeam satellite communication system is designed from scratch to serve a particular area with maximal resource utilization and to satisfactorily accommodate the expected traffic demand. The main design challenge here is setting optimal system parameters such as number of serving beams, beam directions and sizes, and transmit power. This paper aims at developing a tool, multibeam satellite traffic simulator, that helps addressing these fundamental challenges, and more importantly, provides an understanding to the spatial-temporal traffic pattern of satellite networks in large-scale environments. Specifically, traffic demand distribution is investigated by processing credible datasets included three major input categories of information: (i) population distribution for broadband Fixed Satellite Services (FSS), (ii) aeronautical satellite communications, and (iii) vessel distribution for maritime services. This traffic simulator combines this three-dimensional information in addition to time, locations of terminals, and traffic demand. Moreover, realistic satellite beam patterns have been considered in this work, and thus, an algorithm has been proposed to delimit the coverage boundaries of each satellite beam, and then compute the heterogeneous traffic demand at the footprint of each beam. Furthermore, another algorithm has been developed to capture the inherent attributes of satellite channels and the effects of multibeam interference. Data-driven modeling for satellite traffic is crucial nowadays to design innovative communication systems, e.g. precoding and beam hopping, and to devise efficient resource management algorithms. [less ▲]

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See detailDigital Detective Work: Connecting Cheminformatics, Mass Spectrometry and our Environment (analytica Conference)
Schymanski, Emma UL; Bolton, Evan

Scientific Conference (2020, October 20)

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See detailOn the Random Access Procedure of NB-IoT Non-Terrestrial Networks
Kodheli, Oltjon UL; Maturo, Nicola UL; Chatzinotas, Symeon UL et al

Scientific Conference (2020, October 20)

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See detailLowering the obstacles for SMEs to adopt multi-physics biomass furnace simulations by providing a cloud based solution
Rusche, Henrik; Peters, Bernhard UL; Besseron, Xavier UL et al

Scientific Conference (2020, October 14)

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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 detailCollaboration with parents and multiliteracy in early childhood education
Kirsch, Claudine UL; Neumann, Sascha; Aleksic, Gabrijela UL et al

Scientific Conference (2020, October 09)

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See detailPresentación del paquete eph
Rosati, German; Kozlowski, Diego UL; Shokida, Natsumi Solange UL et al

Scientific Conference (2020, October 09)

Working with data produced by public sources often encounters several problems: one of the most common is the lack of continuity in the publication of databases. In this regard, the Permanent Household ... [more ▼]

Working with data produced by public sources often encounters several problems: one of the most common is the lack of continuity in the publication of databases. In this regard, the Permanent Household Survey -EPH- of the National Institute of Statistics and Censuses (INDEC) in Argentina is an exception. In fact, this survey has published user databases with information since 1974. However, this has been done in a "non-replicable" way: from changes in the formats of its publication (dbase, .txt, .xls, .sav, etc.) to renaming some variables and recoding their categories, which makes them impractical for continuous use and processing. The lack of an API for the dissemination of information produced by INDEC generates a limit to the information processing capabilities, reducing the users to i) thematic experts with knowledge of how to access sources and ii) media that access information already processed in the form of press releases. This limits the potential value of the enormous work done by the institute, by discouraging its use by users with limited knowledge of the sources, but with data processing capabilities, such as the R community. In turn, certain key indicators presented by the EPH have methodological annexes, but no public implementations that allow the public to make use of the methodology outside the reports prepared by the institute. In this context, the eph package aims to facilitate the work of those users of the Permanent Household Survey - INDEC who wish to process data from it using the programming language R. The library has the following functionalities: i) a unified syntax for downloading, tagging and building datasets with comparable cross-sectional information ii) Implementation of indicator calculation (poverty) using the official methodology Some of its functions are: get_microdata(): Downloads the microdata bases, organize_panels(): Allows to build a panel data pool of the continuous EPH surveys, organize_cno(): Classifies occupations according to the CNO 2001 organize_caes(): Classifies economic activities according to CAES Mercosur 1.0 and CAES Mercosur organize_labels(): Label the bases following the last design map_agglomerates(): Indicator map by agglomerate The package also has other datasets that can be useful for working with the EPH: some dictionaries that contain the coding of geographic variables (such as regions or clusters) or the geographic position (centroids) of the clusters where the survey is conducted. [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 detailActive Popularity Learning with Cache Hit Ratio Guarantees using a Matrix Completion Committee
Bommaraveni, Srikanth UL; Vu, Thang Xuan UL; Chatzinotas, Symeon UL et al

Scientific Conference (2020, October 08)

Edge caching is a promising technology to facethe stringent latency requirements and back-haul trafficoverloading in 5G wireless networks. However, acquiringthe contents and modeling the optimal cache ... [more ▼]

Edge caching is a promising technology to facethe stringent latency requirements and back-haul trafficoverloading in 5G wireless networks. However, acquiringthe contents and modeling the optimal cache strategy is achallenging task. In this work, we use an active learningapproach to learn the content popularities since it allowsthe system to leverage the trade-off between explorationand exploitation. Exploration refers to caching new fileswhereas exploitation use known files to cache, to achievea good cache hit ratio. In this paper, we mainly focus tolearn popularities as fast as possible while guaranteeing anoperational cache hit ratio constraint. The effectiveness ofproposed learning and caching policies are demonstratedvia simulation results as a function of variance, cache hitratio and used storage. [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 detailResource Allocation for UAV Relay-Assisted IoT Communication Networks
Tran Dinh, Hieu UL; Nguyen, van Dinh UL; Gautam, Sumit UL et al

Scientific Conference (2020, October 06)

This work studies unmanned aerial vehicle (UAV) relay-assisted Internet of Things (IoT) communication networks in which a UAV is deployed as an aerial base station (BS) to collect time-constrained data ... [more ▼]

This work studies unmanned aerial vehicle (UAV) relay-assisted Internet of Things (IoT) communication networks in which a UAV is deployed as an aerial base station (BS) to collect time-constrained data from IoT devices and transfer information to a ground gateway (GW). In this context, we jointly optimize the allocated bandwidth, transmission power, as well as the UAV trajectory to maximize the total system throughput while satisfying the user’s latency requirement and the UAV’s limited storage capacity. The formulated problem is strongly nonconvex which is very challenging to solve optimally. Towards an appealing solution, we first introduce new variables to convert the original problem into a computationally tractable form, and then develop an iterative algorithm for its solution by leveraging the inner approximation method. Numerical results are given to show [less ▲]

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See detailSemantic situation awareness of ellipse shapes via deep learning for multirotor aerial robots with a 2D LIDAR
Sanchez Lopez, Jose Luis UL; Castillo Lopez, Manuel UL; Voos, Holger UL

in 2020 International Conference on Unmanned Aircraft Systems (ICUAS) (2020, October 06)

In this work, we present a semantic situation awareness system for multirotor aerial robots equipped with a 2D LIDAR sensor, focusing on the understanding of the environment, provided to have a drift-free ... [more ▼]

In this work, we present a semantic situation awareness system for multirotor aerial robots equipped with a 2D LIDAR sensor, focusing on the understanding of the environment, provided to have a drift-free precise localization of the robot (e.g. given by GNSS/INS or motion capture system). Our algorithm generates in real-time a semantic map of the objects of the environment as a list of ellipses represented by their radii, and their pose and velocity, both in world coordinates. Two different Convolutional Neural Network (CNN) architectures are proposed and trained using an artificially generated dataset and a custom loss function, to detect ellipses in a segmented (i.e. with one single object) LIDAR measurement. In cascade, a specifically designed indirect-EKF estimates the ellipses based semantic map in world coordinates, as well as their velocity. We have quantitative and qualitatively evaluated the performance of our proposed situation awareness system. Two sets of Software-In-The-Loop simulations using CoppeliaSim with one and multiple static and moving cylindrical objects are used to evaluate the accuracy and performance of our algorithm. In addition, we have demonstrated the robustness of our proposed algorithm when handling real environments thanks to real laboratory experiments with non-cylindrical static (i.e. a barrel) objects and moving persons. [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 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 detailTackling the equivalent mutant problem in real-time systems: the 12 commandments of model-based mutation testing
Basile, Davide; Ter Beek, Maurice; Cordy, Maxime UL et al

in SOFTWARE PRODUCT LINE CONFERENCE (2020, October)

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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 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 detailDissociated face- and word-selective intracerebral responses in the human ventral occipito-temporal cortex
Hagen, Simen; Lochy, Aliette UL; Jacques, Corentin et al

in Journal of Vision (2020, October), 20(11),

The extent to which faces and written words share neural circuitry in the human brain is actively debated. We provide an original contribution to this debate by comparing face-selective and word-selective ... [more ▼]

The extent to which faces and written words share neural circuitry in the human brain is actively debated. We provide an original contribution to this debate by comparing face-selective and word-selective responses in a large group of patients (N=37) implanted with intracerebral electrodes in the ventral occipito-temporal cortex (VOTC). Both face-selective (i.e., significantly different responses to faces vs. nonface objects) and word-selective (i.e., significantly different responses to words vs. pseudofonts) neural activity is isolated through frequency-tagging (Jonas et al., 2016; Lochy et al., 2018, respectively). Critically, this approach allows disentangling category-selective neural responses from general visual responses. Overall, we find that 69.26% of significant contacts show either face- or word-selectivity, with the expected right and left hemispheric dominance, respectively (Fig.1A,B). Moreover, the center of mass for word-contacts is more lateral than for face-contacts, with no differences in postero-anterior axis (Fig.2A). Spatial dissociations are also found within core regions of face and word processing, with a medio-lateral dissociation in the fusiform gyrus (FG) and surrounding sulci (FG+sulci;Fig.2B), while a postero-anterior dissociation is found in the inferior occipital gyrus (IOG;Fig.2C). Despite their spatial dissociations in the FG+sulci and IOG, most overlap in category-selective responses is found in these regions (Fig.1C). Critically, in the overlap-contacts, across the whole brain or specifically in the FG+sulci, between-category (word-face) selective-amplitudes showed no-to-weak correlations, despite strong correlations for within-category (face-face, word-word) selective-amplitudes (Fig.3A), and a strong correlation in non-selective general-amplitudes to words-faces. Moreover, substantial overlap and no-to-weak correlations were observed between faces and a control category (houses) known to be functionally dissociated from faces. Overall, we conclude that category-selectivity for faces and words is largely dissociated in the human VOTC, with a limited spatial overlap likely due to the distant recording of dissociated populations of neurons rather than to shared category-selective representations. [less ▲]

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See detailB/Ordering-Prozesse als Bordertexturen
Wille, Christian UL

Scientific Conference (2020, October)

Angesichts jüngster Re-B/Ordering-Tendenzen (Grenzkontrollen an EU-Binnengrenzen, Euroskeptizismus, Nationalismen, Populismus, komplexe Migrationsdynamiken) ist die Grenzforschung zunehmend stärker ... [more ▼]

Angesichts jüngster Re-B/Ordering-Tendenzen (Grenzkontrollen an EU-Binnengrenzen, Euroskeptizismus, Nationalismen, Populismus, komplexe Migrationsdynamiken) ist die Grenzforschung zunehmend stärker herausgefordert, was sich auch oder vor allem in einer bewegten theoretisch-konzeptionellen Debatte widerspiegelt. Sie hat in den letzten Jahrzehnten eine kaum überschaubare Reihe an Ansätzen und Begriffen hervorgebracht, die inspiriert vom practice turn die Grenze als soziale Praxis in den Mittelpunkt stellen. Der in das Panel einführende Beitrag zeichnet diese Entwicklung nach und stellt darauf aufbauend den Ansatz der Bordertexturen näher vor. Dafür werden im ersten Teil drei analytische Trends der aktuellen Grenzforschung idealtypisch unterschieden. Sie stehen dabei für spezifische Schwerpunktsetzungen in der Beschreibung und Analyse von Grenzen: (1) Zunächst wird die Hinwendung zu Grenzen als soziale Produktionen vorgestellt, die sich an Prozessen ihrer (De-)Stabilisierung festmachen lässt und in (diskursiven) Praktiken manifest wird. Daran anschließend wird (2) eine geweitete Auffassung solcher Prozesse herausgearbeitet, die für die Vielheit der daran beteiligten Aspekte sensibilisiert und einen multiplen Zugriff auf Grenz(de)stabilisierungen einfordert. Schließlich wird (3) die Tendenz zu komplexeren Betrachtungen ausgeführt, die Grenz(de)stabilisierungen als Effekte von dynamischen Formationen verstehen. Im zweiten Teil des Vortrags wird der kulturwissenschaftlich orientierte Ansatz der Bordertexturen vorgestellt, der die für B/Ordering-Prozesse wirksamen Formationen von Wissen, Diskursen, Tätigkeiten, Objekten und Körpern als Texturen fasst. Der Texturbegriff soll die komplexe Verflochtenheit der genannten Konstituenten betonen, eine ‚dichte Beschreibung‘ von Grenz(de)stabilisierungen befördern und in der Grenzforschung für die symbolisch-ästhetische Dimension sensibilisieren. Bordertexturen stehen dabei für komplexe Formationen der Grenz(de)stabilisierung, die rhizomartig strukturiert sind, auf ein multiskalares und azentrisches Geflecht verweisen und ästhetische Verarbeitungen ebenso einschließen wie alltagskulturelle Praktiken. Die Einführung des Ansatzes soll zu den Panelvorträgen hinführen, welche die theoretisch-konzeptionellen Überlegungen an unterschiedliche Gegenstandsbereiche anlegen und diskutieren. [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 detailPVDeConv: Point-Voxel Deconvolution for Autoencoding CAD Construction in 3D
Cherenkova, Kseniya UL; Aouada, Djamila UL; Gusev, Gleb

Scientific Conference (2020, October)

We propose a Point-Voxel DeConvolution (PVDeConv) mod- ule for 3D data autoencoder. To demonstrate its efficiency we learn to synthesize high-resolution point clouds of 10k points that densely describe ... [more ▼]

We propose a Point-Voxel DeConvolution (PVDeConv) mod- ule for 3D data autoencoder. To demonstrate its efficiency we learn to synthesize high-resolution point clouds of 10k points that densely describe the underlying geometry of Computer Aided Design (CAD) models. Scanning artifacts, such as pro- trusions, missing parts, smoothed edges and holes, inevitably appear in real 3D scans of fabricated CAD objects. Learning the original CAD model construction from a 3D scan requires a ground truth to be available together with the corresponding 3D scan of an object. To solve the gap, we introduce a new dedicated dataset, the CC3D, containing 50k+ pairs of CAD models and their corresponding 3D meshes. This dataset is used to learn a convolutional autoencoder for point clouds sampled from the pairs of 3D scans - CAD models. The chal- lenges of this new dataset are demonstrated in comparison with other generative point cloud sampling models trained on ShapeNet. The CC3D autoencoder is efficient with respect to memory consumption and training time as compared to state- of-the-art models for 3D data generation. [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 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 detailZwischen Gehege und Idylle: Durs Grünbeins "Heimat"
Kohns, Oliver UL

Scientific Conference (2020, October)

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See detailA Security and Privacy Focused KYC Data Sharing Platform
Norvill, Robert UL; Cyril, Cassagnes; Wazen, Shbair et al

in Proceedings of the 2nd ACM International Symposium on Blockchain and Secure Critical Infrastructure (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 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 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 detailUsing word embeddings to explore the Aboriginality discourse in a corpus of Australian Aboriginal autobiographies
Kamlovskaya, Ekaterina UL; Schommer, Christoph UL

Scientific Conference (2020, September 29)

This submission presents intermediate results of the PhD project analysing discourses in a corpus of Australian Aboriginal autobiographies with word embedding modelling.

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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 detailIdentität im Spannungsfeld der Migrationsbewegung
Murdock, Elke UL

Scientific Conference (2020, September 21)

Die Rahmenbedingungen bei der Migration von deutschen Staatsangehöriger können – v. a. im Vergleich zu den meisten Migrantengruppen, die in der Forschung betrachtet werden – als privilegiert und günstig ... [more ▼]

Die Rahmenbedingungen bei der Migration von deutschen Staatsangehöriger können – v. a. im Vergleich zu den meisten Migrantengruppen, die in der Forschung betrachtet werden – als privilegiert und günstig beschrieben werden. Die deutsche Staatsangehörigkeit garantiert zum Beispiel einen leichten Zugang zu den meisten Ländern der Welt (Visa-Germany 2020). Zudem ist die Entscheidung zur Ausreise meist freiwillig, auf Basis ganz unterschiedlicher Beweggründe getroffen und die Möglichkeit zur Rückreise zumeist auch gegeben. Selbst wenn „Deutsch sein“ für die Auswanderer kein identitätsbestimmendes Merkmal war, werden sie im Ausland über die Kategorie „Deutsch“ wahrgenommen. Auf der einen Seite wird also über diese kategoriale Zuschreibung von außen eine Auseinandersetzung mit eignen Herkunftsland angeregt, auf der anderen Seite werden auch erst in der Kulturkontakterfahrung, wenn Selbstverständlichkeiten im alltäglichen Leben nicht mehr greifen, eigene Vorstellungen, Erwartungen und Werte bewusst und können reflektiert werden. Es gibt interindividuelle Unterschiede in Bezug auf die Bereitschaft sich mit solchen Unterschieden auseinanderzusetzen, einen Perspektivenwechsel einzunehmen und den eigenen Standpunkt zu hinterfragen (Tadmor und Tetlock, 2006). Die Bewertung dieser Erfahrung als bereichernd oder belastend ist ebenfalls sehr unterschiedlich. Die Frage der Konsequenzen der Mobilitätserfahrung für die eigene Identität und das Gefühl der Zugehörigkeit zu Deutschland bzw. dem Gastland lässt sich mit Hilfe der „German Emigration and Remigration Panel Study“ (GERPS) empirisch untersuchen. Die Determinanten dieses Zugehörigkeitsgefühls sowohl zum Gastland als auch zum Heimatland sollen im Verlaufe der Mobilitätserfahrung näher beleuchtet werden. Erste Resultate der Auswertung der ersten Welle zeigen, dass etwa die Hälfte der Auswanderer sich mit ihrem Auswanderungsland verbunden fühlen, wobei die Bleibeperspektive ein wichtiger Prädiktor ist. Ebenso wie der Migrationsprozess selbst, wird auch die Identitätsbildung als lebenslanger, dynamischer, unabgeschlossener und mehrdimensionaler Prozess verstanden. Aufbauend auf dieser Annahme und dem Akkulturationsrahmenmodell von Arends-Tóth und van de Vijver (2006) wird ein theoretisches Modell vorgestellt, mit Hilfe dessen Identität im Spannungsfeld der Migration untersucht werden kann. [less ▲]

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See detailMeasuring the Environmental Exposome (ISES2020)
Schymanski, Emma UL

Scientific Conference (2020, September 21)

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See detailActor-Critic Deep Reinforcement Learning for Energy Minimization in UAV-Aided Networks
Yuan, Yaxiong UL; Lei, Lei UL; Vu, Thang Xuan UL et al

in 2020 European Conference on Networks and Communications (EuCNC) (2020, September 21)

In this paper, we investigate a user-timeslot scheduling problem for downlink unmanned aerial vehicle (UAV)-aided networks, where the UAV serves as an aerial base station. We formulate an optimization ... [more ▼]

In this paper, we investigate a user-timeslot scheduling problem for downlink unmanned aerial vehicle (UAV)-aided networks, where the UAV serves as an aerial base station. We formulate an optimization problem by jointly determining user scheduling and hovering time to minimize UAV’s transmission and hovering energy. An offline algorithm is proposed to solve the problem based on the branch and bound method and the golden section search. However, executing the offline algorithm suffers from the exponential growth of computational time. Therefore, we apply a deep reinforcement learning (DRL) method to design an online algorithm with less computational time. To this end, we first reformulate the original user scheduling problem to a Markov decision process (MDP). Then, an actor-critic-based RL algorithm is developed to determine the scheduling policy under the guidance of two deep neural networks. Numerical results show the proposed online algorithm obtains a good tradeoff between performance gain and computational time. [less ▲]

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See detailPractical Use Cases for Ethernet Redundancy
Pannell, Don; Navet, Nicolas UL

Scientific Conference (2020, September 17)

Autonomous driving requires safety considerations and the need of “fail operational” requires redundancy. In the networking portion of a car, this may mean separate networks, possibly of different ... [more ▼]

Autonomous driving requires safety considerations and the need of “fail operational” requires redundancy. In the networking portion of a car, this may mean separate networks, possibly of different technologies. Or it could mean a network topology and technology that supports scalable redundancy, like Ethernet TSN. This presentation focuses on IEEE 802.1CB-2017, which is the TSN standard that supports data redundancy through the network. Various network topologies are examined. The relative costs of adding TSN redundancy for these topologies (including some, or all of, the end-stations/ECUs & bridges) are examined for various bandwidth utilizations, along with the expected packet loss. Each topology and bandwidth will be modeled under various bit-rate error values with the results discussed. This presentation aims at providing a clear understanding of the TSN standards that support redundancy, and an understanding of the cost/benefit tradeoffs so proper engineering decisions can be made and proper expectations set. [less ▲]

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See detailUrban repair networks: the City of Luxembourg and Esch-Sur-Alzette
Hoppenheit, Thomas UL

Scientific Conference (2020, September 17)

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See detailFIXING THE TELEPHONE Communicating through the wired dispositives of a large technological system
Mossop, Rebecca UL

Scientific Conference (2020, September 17)

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See detailSchadstoffen auf der Spur mit Umweltcheminformatik
Schymanski, Emma UL

Scientific Conference (2020, September 17)

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See detailTowards Computer-Aided, Iterative TSN-and Ethernet-based E/E Architecture Design
Creighton, Oliver; Navet, Nicolas UL; Keller, Patrick UL et al

Scientific Conference (2020, September 16)

In this presentation we would like to propose a novel approach towards studying and simulating candidate designs of next generation Ethernet architectures at established OEMs that intend to employ 100BASE ... [more ▼]

In this presentation we would like to propose a novel approach towards studying and simulating candidate designs of next generation Ethernet architectures at established OEMs that intend to employ 100BASE-T1, 1000BASE-T1 and, for increased flexibility and lower cost, 10BASE-T1S. Typical design goals of next generation architectures are future extensibility and cost optimization of the lowest-end. We propose to introduce guidance to an otherwise standard Monte-Carlo simulation by providing certain fixed points (e.g., mandated connections of ECUs to certain bridges, complete re-use of ECUs) and “hot spots” in the topology (e.g., ECUs with the highest variability pressure) that are known in advance from BMW’s experience with their vehicles in the field. Several important practical considerations must be integrated in the generation of candidate architectures: - Topological constraints: ECU proximity to sensors, daisy chain connections between ECUs to minimize cable length, number of switch ports in a certain ECU, etc. - Security and reliability requirements: segregation between mixed-criticality streams, proxy ECUs, and redundant paths. Our position statement explores the ability of algorithmic tools to synthesize Ethernet-based architectures based on a minimal fixed core TSN topology, design goals, design constraints, assumptions about next generation applications and data from past projects (capturing part of the OEM domain knowledge). [less ▲]

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See detailScaling of urban heat island & NO2 with urban population: a meta-analysis
Wei, Yufei UL; Caruso, Geoffrey UL; Lemoy, Rémi

Scientific Conference (2020, September 16)

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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 detailAutomatic Detection of Nigrosome Degeneration in Susceptibility-Weighted MRI for Computer-Aided Diagnosis of Parkinson’s Disease Using Machine Learning
Garcia Santa Cruz, Beatriz UL; Husch, Andreas UL; Hertel, Frank UL

in Movement Disorders: Volume 35, Number S1, September 2020 (2020, September 12)

Objective: Automatize the detection of ‘swallow-tail’ appearance in substantia nigra dopaminergic neurons using MRI for more robust tests on Parkinson’s disease (PD) diagnosis. Background: Differential ... [more ▼]

Objective: Automatize the detection of ‘swallow-tail’ appearance in substantia nigra dopaminergic neurons using MRI for more robust tests on Parkinson’s disease (PD) diagnosis. Background: Differential diagnosis of PD is challenging even in specialized centers. The use of imaging techniques can be bene cial for the diagnosis. Although DaTSCAN has been proven to be clinically useful, it is not widely available and has radiation risk and high-cost associated. Therefore, MRI scans for PD diagnosis offer several advantages over DaTSCAN [1]. Recent literature shows strong evidence of high diagnostic accuracy using the ‘swallow-tail’ shape of the dorsolateral substantia nigra in 3T – SWI [2]. Nevertheless, the majority of such studies rely on the subjective opinion of experts and manual methods for the analysis to assess the accuracy of these features. Alternatively, we propose a fully automated solution to evaluate the absence or presence of this feature for computer-aided diagnosis (CAD) of PD. Method: Restrospective study of 27 PD and 18 non-PD was conducted, including standard high-resolution 3D MRI – T1 & SWI sequences (additionally, T2 scans were used to increase the registration references). Firstly, spatial registration and normalization of the images were performed. Then, the ROI was extracted using atlas references. Finally, a supervised machine learning model was built using 5-fold-within-5-fold nested cross-validation. Results: Preliminary results show signi cant sensitivity (0.92) and ROC AUC (0.82), allowing for automated classi cation of patients based on swallow-tail biomarker from MRI. Conclusion: Detection of nigrosome degeneration (swallow-tail biomarker) in accessible brain imaging techniques can be automatized with signi cant accuracy, allowing for computer-aided PD diagnosis. References: [1] Schwarz, S. T., Xing, Y., Naidu, S., Birchall, J., Skelly, R., Perkins, A., ... & Gowland, P. (2017). Protocol of a single group prospective observational study on the diagnostic value of 3T susceptibility weighted MRI of nigrosome-1 in patients with parkinsonian symptoms: the N3iPD study (nigrosomal iron imaging in Parkinson’s disease). BMJ open, 7(12), e016904. [2] – Schwarz, S. T., Afzal, M., Morgan, P. S., Bajaj, N., Gowland, P. A., & Auer, D. P. (2014). The ‘swallow tail’ appearance of the healthy nigrosome –a new accurate test of Parkinson’s disease: a case-control and retrospective cross-sectional MRI study at 3T. PloS one, 9(4). [less ▲]

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See detailGoverning Health in the European Semester: Towards the Economy of Wellbeing?
Muñoz, Susana UL

Scientific Conference (2020, September 11)

Health is a key component of the Economy of Wellbeing, the new horizontal approach to political decision-making and governance adopted by the Council of the European Union on 24 October 2019. Building on ... [more ▼]

Health is a key component of the Economy of Wellbeing, the new horizontal approach to political decision-making and governance adopted by the Council of the European Union on 24 October 2019. Building on the principles of the European Pillar of Social Rights and on the Health in All Policies and One Health approaches, it seeks to strengthen the role of employment, social, health and education policies within the European Semester. Nevertheless, “wellbeing” acquires a new resonance for the post COVID-19 “Economy of Recovery”. Against this backdrop, this paper aims to provide a critical review of the effectiveness of the European Semester as a governance tool for the “wellbeing” policies from the perspective of EU law and policy- making and enforcement. It also examines future prospects in the light of the multiple impacts of the current health and socioeconomic crises. [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 detaildigitizing of Research and Teaching
Plapper, Peter UL

Scientific Conference (2020, September 05)

The current Covid-19 crisis impacts all manufacturing areas and new processes are sought. This presentation provides the audience with three examples related to assembly work instructions, logistics data ... [more ▼]

The current Covid-19 crisis impacts all manufacturing areas and new processes are sought. This presentation provides the audience with three examples related to assembly work instructions, logistics data handling and manufacturing education, for which innovative ways to obtain access to context sensitive data based on digital tools are investigated. Augmented Reality (AR) and Virtual Reality (VR) facilitate access to relevant manufacturing information. In order to provide logistic warehouse workers with immediate access to shipping documents, to avoid paper print-outs, and to eliminate error-prone typing of information, critical information should be handled digitally and hands-free. To support logistic workers to efficiently document, register and trace receipt, storage or delivery of goods, the presented solution is built on hands-free digital tools with AR technology in commercially available smart glasses. Similarly, workers who execute complex assembly operations frequently require either assistance or support for the next assembly step. Depending on the context, relevant assembly process information is automatically displayed together with the environment in the AR smart glass. Thus, the operator is supported by the presented hands-free-tool to complete the next challenging tasks. Currently, teaching is being transferred from physical class-room teaching to remote or hybrid education. For this purpose, Virtual Reality (VR) provides a very welcome opportunity to complement in-presence teaching with exposure to examples of real manufacturing operations captured in videos of industrial case studies. Students apply learnings from theoretical classes to manufacturing case studies by identifying best practices and also recognizing waste. The presentation shares experience in teaching of lean methods based on AR technology to graduate engineering students. [less ▲]

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See detailBioKC: a platform for quality controlled curation and annotation of systems biology models
Vega Moreno, Carlos Gonzalo UL; Groues, Valentin UL; Ostaszewski, Marek UL et al

Scientific Conference (2020, September 04)

Standardisation of biomedical knowledge into systems biology models is essential for the study of the biological function. However, biomedical knowledge curation is a laborious manual process aggravated ... [more ▼]

Standardisation of biomedical knowledge into systems biology models is essential for the study of the biological function. However, biomedical knowledge curation is a laborious manual process aggravated by the ever increasing growth of biomedical literature. High quality curation currently relies on pathway databases where outsider participation is minimal. The increasing demand of systems biology knowledge presents new challenges regarding curation, calling for new collaborative functionalities to improve quality control of the review process. These features are missing in the current systems biology environment, whose tools are not well suited for an open community-based model curation workflow. On one hand, diagram editors such as CellDesigner or Newt provide limited annotation features. On the other hand, most popular text annotations tools are not aimed for biomedical text annotation or model curation. Detaching the model curation and annotation tasks from diagram editing improves model iteration and centralizes the annotation of such models with supporting evidence. In this vain, we present BioKC, a web-based platform for systematic quality-controlled collaborative curation and annotation of biomedical knowledge following the standard data model from Systems Biology Markup Language (SBML). [less ▲]

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See detailThe Job demands-resources model: A validation with employees working in Luxembourg
Fernandez de Henestrosa, Martha UL; Sischka, Philipp UL; Steffgen, Georges UL

Poster (2020, September 02)

Purpose: The present study aimed to validate the job demands-resources model (Bakker & Demerouti, 2017) among a representative sample of the worker population in Luxembourg. Moreover, our purpose was to ... [more ▼]

Purpose: The present study aimed to validate the job demands-resources model (Bakker & Demerouti, 2017) among a representative sample of the worker population in Luxembourg. Moreover, our purpose was to identify which specific job demands and resources contribute the most to burnout and work engagement, respectively. Design: Data were collected via computer assisted telephone and web interview in a large sample of 1689 employees working in Luxembourg (55.2% male, Mage = 44.1, SDage = 10.3). Most participants worked in academic professions (31.4%, n = 531), followed by technicians and associate professionals (24.0%, n = 406), clerical support workers (11.7%, n = 197) and others (32.86%, n = 555). We employed the Quality of Work Index – Luxembourg (QoWIL) to measure several areas of work, including work intensity, job design, physical and social conditions (Sischka & Steffgen, 2019). Additionally, different employment conditions were measured to get an indicator of the employment quality in Luxembourg. Findings: Results of latent moderated structural equation modelling (LMS) indicated a good fit of the model to the data, χ2(411) = 1738.017, RMSEA = .04 (95% CI = 0.04 - 0.05), CFI =.92, SRMR = .06. All job resources (i.e. social support, autonomy and job security) significantly predicted work engagement, whereas all demands (i.e. workplace mobbing, work-life inference, emotional demands) significantly predicted burnout. Particularly, social support was the most important resource (ß = .29, p < .001, R2 = 11.4%), followed by job security (ß = .17, p < .001, R2 = 3.9%) and autonomy (ß = .11, p < .001, R2 = 1.4%). Workplace mobbing explained the largest percentage of variance in burnout (ß =. 47, p < .001, R2 = 41.6%), followed by work home inference (ß = .30, p < .001, R2 = 13.0%) and emotional demands (ß = 15, p < .001, R2 = 2.2%). While burnout had a negative impact on job performance (ß = -18, p < .001), work engagement did not predict the latter (ß = .07, p > .05). Besides, only one out of nine hypothesized interaction effects had a significant effect on work engagement (i.e. social support x mobbing, ß = 0.15, p < .001) and on burnout (i.e. social support x emotional demands, ß = -0.08, p < .05). Conclusion: Whereas the present findings provided strong support for the motivational and health impairment processes proposed by the JDR model, we found limited support for the interaction hypotheses. The results outline the importance of social conditions in explaining employees’ health, illustrating important starting points for organizational interventions that aim to promote well-being. Contributions: While other studies have tested the propositions of the JDR model by focusing on different work sectors, the present study includes a more comprehensive range of occupations,classified according to the ISCO-08. Given its large data set, it provides enough statistical support to detect interaction effects and allows for the correction of measurement errors using LMS. Furthermore, it follows the parsimony principle by specifying the most important starting points for interventions across occupations. [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 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 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 detailA Quantitative Analysis of Security, Anonymity and Scalability for the Lightning Network
Tikhomirov, Sergei UL; Moreno-Sanchez, Pedro; Maffei, Matteo

in Proceedings of 2020 IEEE European Symposium on Security and Privacy (EuroS&P) (2020, September)

Payment channel networks have been introduced to mitigate the scalability issues inherent to permissionless decentralized cryptocurrencies such as Bitcoin. Launched in 2018, the Lightning Network (LN) has ... [more ▼]

Payment channel networks have been introduced to mitigate the scalability issues inherent to permissionless decentralized cryptocurrencies such as Bitcoin. Launched in 2018, the Lightning Network (LN) has been gaining popularity and consists today of more than 5000 nodes and 30000 payment channels that jointly hold 895 bitcoins (7.6M USD as of February 2020). This adoption has motivated research from both academia and industry. Payment channels suffer from security vulnerabilities, such as the wormhole attack, anonymity issues, and scalability limitations related to the upper bound on the number of concurrent payments per channel, which have been pointed out by the scientific community but never quantitatively analyzed. In this work, we first analyze the proneness of the LN to the wormhole attack and attacks against anonymity. We observe that an adversary needs to control only 2% of LN nodes to learn sensitive payment information (e.g., sender, receiver and payment amount) or to carry out the wormhole attack. Second, we study the management of concurrent payments in the LN and quantify its negative effect on scalability. We observe that for micropayments, the forwarding capability of up to 50% of channels is restricted to a value smaller than the overall channel capacity. This phenomenon not only hinders scalability but also opens the door for DoS attacks: We estimate that a network-wide DoS attack costs within 1.5M USD, while isolating the biggest community from the rest of the network costs only 225k USD. Our findings should prompt the LN community to consider the security, privacy and scalability issues of the network studied in this work when educating users about path selection algorithms, as well as to adopt multi-hop payment protocols that provide stronger security, privacy and scalability guarantees. [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 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 detailScientific Instruments in Constcamer Paintings: Pictorial Space as a Context for Interpretation
Koeleman, Floor UL

Scientific Conference (2020, September)

Representations of scientific instruments abound in the seventeenth-century genre of constcamer paintings. These works of art depict interiors full of rich collections of artifacts, natural materials ... [more ▼]

Representations of scientific instruments abound in the seventeenth-century genre of constcamer paintings. These works of art depict interiors full of rich collections of artifacts, natural materials, animals and people, and were created almost exclusively in Antwerp and Brussels. In contrast to material and written sources, such images provide us with a context, captured in paint, which contributes to our understanding of the contemporary meaning of scientific instruments. This presentation will highlight the wide variety of instruments (mainly optical and mathematical) that are included in constcamer paintings. Depending on how we define ‘scientific instrument’, between 63 and 100 constcamer paintings from the early modern period can be identified as including representations of scientific instruments. The study of these images from the perspective of the visual and material culture of science not only provides further insight into the variety of instruments that existed at the time, but also sheds light on how painters produced these representations, either by using an actual object or by resorting to a preexisting depiction. It will be shown that the instruments in the paintings reflect a thriving glass industry and the activity of skilled goldsmiths in local workshops and at the archducal court. While over the course of the seventeenth century the novelty of such instruments declined, their association with knowledge of nature, the role of vision and the art of painting persisted. As such, the instruments in constcamer paintings denote both a practical and a philosophical dimension, relating to the world of the senses as well as the intellect. [less ▲]

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See detailNumerical Analysis of Interaction between a Reacting Fluid and a Moving Bed with Spatially and Temporally Fluctuating Porosity
Rousset, Alban UL; Mainassara Chekaraou, Abdoul Wahid UL; Besseron, Xavier UL et al

Scientific Conference (2020, August 31)

The purpose of this study is to propose a numerical approach that combines low computational costs through the use of high computing efficiency, allowing the realistic use of the design with a sufficient ... [more ▼]

The purpose of this study is to propose a numerical approach that combines low computational costs through the use of high computing efficiency, allowing the realistic use of the design with a sufficient result's accuracy for industrial applications to investigate biomass combustion in a large-scale reciprocating grate. In the present contribution, a Biomass 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 an HPC 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 grate system has three different moving sections to ensure good mixing of the biomass parts and appropriate residence time. The primary air enters from below the grate and is split into four different zones. Furthermore, a secondary air is injected at high velocity straight over the fuel bed through nozzles. A Flue Gas Recirculation is present and partly injected through two jets along the vertical channel and partly from below the grate. The numerical 3D model presented is based on a multi-phase approach. The biomass particles are taken into consideration via the XDEM Method, while the gaseous phase is described by CFD with OpenFOAM. Thus, the combustion of the particles on the moving beds in the furnace is processed by XDEM through conduction, radiation and conversion along with the interaction with the surrounding gas phase accounted for by CFD. The coupling of CFD-XDEM as an Euler-Lagrange model is used. The fluid phase is a continuous phase handled with an Eulerian approach and each particle is tracked with a Lagrangian approach. Energy, mass and momentum conservation is applied for every single particle and the interaction of particles with each other in the bed and with the surrounding gas phase are taken into account. An individual particle can have a solid, liquid, gas or inert material phases (immobile species) at the same time. The different phases can undergo a series of conversion through various reactions that can be homogeneous, heterogeneous or intrinsic (drying, pyrolysis, gasification and oxidation). Our first results are consistent with actual data obtained from the sampling of the residual solid in the industrial plant. Our model is also able to predict gas flux behaviour inside the furnace, particularly the flue gas recirculation on the combustion process injection. [less ▲]

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See detailAnaerobe Vergärung von (synthetischem) Küchenabfall in zweistufigem Semi-Konti-Betrieb
Sobon, Elena UL; Schlienz, Markus UL; Greger, Manfred UL

in Chemie Ingenieur Technik (2020, August 28), 92(9), 1267-1268

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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 detailDecomposition schemes for symmetric n-ary bands
Devillet, Jimmy UL; Mathonet, Pierre

Scientific Conference (2020, August 27)

We extend the classical (strong) semilattice decomposition scheme of certain classes of semigroups to the class of idempotent symmetric n-ary semigroups (i.e. symmetric n-ary bands) where n \geq 2 is an ... [more ▼]

We extend the classical (strong) semilattice decomposition scheme of certain classes of semigroups to the class of idempotent symmetric n-ary semigroups (i.e. symmetric n-ary bands) where n \geq 2 is an integer. More precisely, we show that these semigroups are exactly the strong n-ary semilattices of n-ary extensions of Abelian groups whose exponents divide n-1. We then use this main result to obtain necessary and sufficient conditions for a symmetric n-ary band to be reducible to a semigroup. [less ▲]

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See detailSHARP 2020: The 1st Shape Recovery from Partial Textured 3D Scans Challenge Results
Saint, Alexandre Fabian A UL; Kacem, Anis UL; Cherenkova, Kseniya UL et al

Scientific Conference (2020, August 23)

The SHApe Recovery from Partial textured 3D scans challenge, SHARP 2020, is the first edition of a challenge fostering and benchmarking methods for recovering complete textured 3D scans from raw ... [more ▼]

The SHApe Recovery from Partial textured 3D scans challenge, SHARP 2020, is the first edition of a challenge fostering and benchmarking methods for recovering complete textured 3D scans from raw incomplete data. SHARP 2020 is organized as a workshop in conjunction with ECCV 2020. There are two complementary challenges, the first one on 3D human scans, and the second one on generic objects. Challenge 1 is further split into two tracks, focusing, first, on large body and clothing regions, and, second, on fine body details. A novel evaluation metric is proposed to quantify jointly the shape reconstruction, the texture reconstruction, and the amount of completed data. Additionally, two unique datasets of 3D scans are proposed, to provide raw ground-truth data for the benchmarks. The datasets are released to the scientific community. Moreover, an accompanying custom library of software routines is also released to the scientific community. It allows for processing 3D scans, generating partial data and performing the evaluation. Results of the competition, analyzed in comparison to baselines, show the validity of the proposed evaluation metrics and highlight the challenging aspects of the task and of the datasets. Details on the SHARP 2020 challenge can be found at https://cvi2.uni.lu/sharp2020/ [less ▲]

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See detail3DBooSTeR: 3D Body Shape and Texture Recovery
Saint, Alexandre Fabian A UL; Kacem, Anis UL; Cherenkova, Kseniya UL et al

Scientific Conference (2020, August 23)

We propose 3DBooSTeR, a novel method to recover a textured 3D body mesh from a textured partial 3D scan. With the advent of virtual and augmented reality, there is a demand for creating realistic and high ... [more ▼]

We propose 3DBooSTeR, a novel method to recover a textured 3D body mesh from a textured partial 3D scan. With the advent of virtual and augmented reality, there is a demand for creating realistic and high-fidelity digital 3D human representations. However, 3D scanning systems can only capture the 3D human body shape up to some level of defects due to its complexity, including occlusion between bodyparts, varying levels of details, shape deformations and the articulated skeleton. Textured 3D mesh completion is thus important to enhance3D acquisitions. The proposed approach decouples the shape and texture completion into two sequential tasks. The shape is recovered by an encoder-decoder network deforming a template body mesh. The texture is subsequently obtained by projecting the partial texture onto the template mesh before inpainting the corresponding texture map with a novel approach. The approach is validated on the 3DBodyTex.v2 dataset [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 detailRIVER MORPHOLOGY MONITORING OF A SMALL-SCALE ALPINE RIVERBED USING DRONE PHOTOGRAMMETRY AND LIDAR
Backes, Dietmar UL; Smigaj, Magdalena; Schimka, Marian et al

in The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences (2020, August 12), XLIII-B2-2020 Article Metrics Related articles(1017), 1024

An efficient alternative to labour-intensive terrestrial and costly airborne surveys is the use of small, inexpensive Unmanned Aerial Vehicles (UAVs) or Remotely Piloted Aerial Systems (RPAS). These low ... [more ▼]

An efficient alternative to labour-intensive terrestrial and costly airborne surveys is the use of small, inexpensive Unmanned Aerial Vehicles (UAVs) or Remotely Piloted Aerial Systems (RPAS). These low-altitude remote sensing platforms, commonly known as drones, can carry lightweight optical and LiDAR sensors. Even though UAV systems still have limited endurance, they can provide a flexible and relatively inexpensive monitoring solution for a limited area of interest. This study investigated the applicability of monitoring the morphology of a frequently changing glacial stream using high-resolution topographic surface models derived from low-altitude UAV-based photogrammetry and LiDAR. An understanding of river-channel morphology and its response to anthropogenic and natural disturbances is imperative for effective watershed management and conservation. We focus on the data acquisition, processing workflow and highlight identified challenges and shortcomings. Additionally, we demonstrate how LiDAR data acquisition simulations can help decide which laser scanning approach to use and help optimise data collection to ensure full coverage with desired level of detail. Lastly, we showcase a case study of 3D surface change analysis in an alpine stream environment with UAV-based photogrammetry. The datasets used in this study were collected as part of the ISPRS Summer School of Alpine Research, which will continue to add new data layers on a biyearly basis. This growing data repository is freely available for research. [less ▲]

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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 detailComparing Offline and Online Testing of Deep Neural Networks: An Autonomous Car Case Study
Ul Haq, Fitash UL; Shin, Donghwan UL; Nejati, Shiva UL et al

in 2020 IEEE 13th International Conference on Software Testing, Validation and Verification (ICST) (2020, August 05)

There is a growing body of research on developing testing techniques for Deep Neural Networks (DNN). We distinguish two general modes of testing for DNNs: Offline testing where DNNs are tested as ... [more ▼]

There is a growing body of research on developing testing techniques for Deep Neural Networks (DNN). We distinguish two general modes of testing for DNNs: Offline testing where DNNs are tested as individual units based on test datasets obtained independently from the DNNs under test, and online testing where DNNs are embedded into a specific application and tested in a close-loop mode in interaction with the application environment. In addition, we identify two sources for generating test datasets for DNNs: Datasets obtained from real-life and datasets generated by simulators. While offline testing can be used with datasets obtained from either sources, online testing is largely confined to using simulators since online testing within real-life applications can be time consuming, expensive and dangerous. In this paper, we study the following two important questions aiming to compare test datasets and testing modes for DNNs: First, can we use simulator-generated data as a reliable substitute to real-world data for the purpose of DNN testing? Second, how do online and offline testing results differ and complement each other? Though these questions are generally relevant to all autonomous systems, we study them in the context of automated driving systems where, as study subjects, we use DNNs automating end-to-end control of cars' steering actuators. Our results show that simulator-generated datasets are able to yield DNN prediction errors that are similar to those obtained by testing DNNs with real-life datasets. Further, offline testing is more optimistic than online testing as many safety violations identified by online testing could not be identified by offline testing, while large prediction errors generated by offline testing always led to severe safety violations detectable by online testing. [less ▲]

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See detailLeveraging eBPF to preserve user privacy for DNS, DoT, and DoH queries
Rivera, Sean UL; Gurbani, Vijay; Lagraa, Sofiane UL et al

in Proceedings of the 15th International Conference on Availability, Reliability and Security (2020, August)

The Domain Name System (DNS), a fundamental protocol that controls how users interact with the Internet, inadequately provides protection for user privacy. Recently, there have been advancements in the ... [more ▼]

The Domain Name System (DNS), a fundamental protocol that controls how users interact with the Internet, inadequately provides protection for user privacy. Recently, there have been advancements in the field of DNS privacy and security in the form of the DNS over TLS (DoT) and DNS over HTTPS (DoH) protocols. The advent of these protocols and recent advancements in large-scale data processing have drastically altered the threat model for DNS privacy. Users can no longer rely on traditional methods, and must instead take active steps to ensure their privacy. In this paper, we demonstrate how the extended Berkeley Packet Filter (eBPF) can assist users in maintaining their privacy by leveraging eBPF to provide privacy across standard DNS, DoH, and DoT communications. Further, we develop a method that allows users to enforce application-specific DNS servers. Our method provides users with control over their DNS network traffic and privacy without requiring changes to their applications while adding low overhead. [less ▲]

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See detailPeer influence in individuals with developmental disabilities
Zurbriggen, Carmen UL

Scientific Conference (2020, August)

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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 detailCollective Knowledge Production in Educational Ethnography: From Team-Ethnography to European Cooperation and Beyond
Maeder, Christoph; Kuhn, Melanie; Neumann, Sascha et al

Scientific Conference (2020, August)

Ethnography can be regarded as being inherently collaborative (see: Lassiter 2005). But if we accept ethnography as a collaborative, cooperative and joint production of knowledge, many questions namely ... [more ▼]

Ethnography can be regarded as being inherently collaborative (see: Lassiter 2005). But if we accept ethnography as a collaborative, cooperative and joint production of knowledge, many questions namely around cooperation within and between people, projects, disciplines, places, organizations and research teams etc. arise. In this panel discussion we want to explore and discuss questions and challenges of different levels of collaboration, or ways of working together in educational ethnography under the auspices of the production of knowledge on education. [...] [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 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 detailManaging residence permits and migrant unemployment during the COVID-19 crisis
Sommarribas, Adolfo UL

Scientific Conference (2020, July 30)

This presentation deals on how immigration authorities in European Union Member States and Norway dealt with third-country national residence permits and how they are dealing with third-country nationals ... [more ▼]

This presentation deals on how immigration authorities in European Union Member States and Norway dealt with third-country national residence permits and how they are dealing with third-country nationals who are losing their employment in regard to their right to stay in the host countries. [less ▲]

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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 detailWorking with Deep Generative Models and Tabular Data Imputation
Camino, Ramiro Daniel UL; Hammerschmidt, Christian UL; State, Radu UL

Scientific Conference (2020, July 17)

Datasets with missing values are very common in industry applications. Missing data typically have a negative impact on machine learning models. With the rise of generative models in deep learning, recent ... [more ▼]

Datasets with missing values are very common in industry applications. Missing data typically have a negative impact on machine learning models. With the rise of generative models in deep learning, recent studies proposed solutions to the problem of imputing missing values based various deep generative models. Previous experiments with Generative Adversarial Networks (GANs) and Variational Autoencoders (VAEs) showed promising results in this domain. Initially, these results focused on imputation in image data, e.g. filling missing patches in images. Recent proposals addressed missing values in tabular data. For these data, the case for deep generative models seems to be less clear. In the process of providing a fair comparison of proposed methods, we uncover several issues when assessing the status quo: the use of under-specified and ambiguous dataset names, the large range of parameters and hyper-parameters to tune for each method, and the use of different metrics and evaluation methods. [less ▲]

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See detailReservoir Computing with Random Chemical Systems
Nguyen, Hoang; Banda, Peter UL; Stefanovic, Darko et al

in ALIFE 2020: The 2020 Conference on Artificial Life (2020, July 14)

Top-down engineering of biomolecular circuits to perform specific computational tasks is notoriously hard and time-consuming. Current circuits have limited complexity and are brittle and application ... [more ▼]

Top-down engineering of biomolecular circuits to perform specific computational tasks is notoriously hard and time-consuming. Current circuits have limited complexity and are brittle and application-specific. Here we propose an alternative: we design and test a bottom-up constructed Reservoir Computer (RC) that uses random chemical circuits inspired by DNA strand displacement reactions. This RC has the potential to be implemented easily and trained for various tasks. We describe and simulate it by means of a Chemical Reaction Network (CRN) and evaluate its performance on three computational tasks: the Hamming distance and a short- as well as a long-term memory. Compared with the deoxyribozyme oscillator RC model simulated by Yahiro et al., our random chemical RC performs 75.5% better for the short-term and 67.2% better for the long-term memory task. Our model requires an 88.5% larger variety of chemical species, but it relies on random chemical circuits, which can be more easily realized and scaled up. Thus, our novel random chemical RC has the potential to simplify the way we build adaptive biomolecular circuits. [less ▲]

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See detailSTEAM Education in elementary schools: A holistic investigation on technology enhanced teaching and learning
Haas, Ben; Lavicza, Zsolt; Kreis, Yves UL

Scientific Conference (2020, July 03)

When we address the learning of mathematics in elementary school, we imagine pupils doing experiments, discoveries, and combining the different elements from arithmetics to geometry. Pupils interact with ... [more ▼]

When we address the learning of mathematics in elementary school, we imagine pupils doing experiments, discoveries, and combining the different elements from arithmetics to geometry. Pupils interact with their environment and try to use their learned skills to get a deeper understanding of the world. They engage in a mathematical thinking process and try to interact with their environment. However, when you visit a classroom, you find a rather old fashioned teaching based on a deductive approach where imitations of technics play an essential role. Based on our observations, pupils learn mainly through to repetitions in textbooks. Experimentation, if any, comes as additional work, it is seen as a ludic activity rather than as real learning activity. In our research, we inquired about different ways to engage pupils in an experimental approach. We used digital and physical modulation, augmented reality, and various educational technologies. In one of our first studies, we designed a tutoring system to foster process-related skills in mathematics within the educational software MathemaTIC . We collected data on pupils in assessments on transferring mathematical thinking from instructional technology to the everyday classroom teaching. In a second study, we worked with pupils from elementary schools, kindergarten, and from the special needs section to go beyond two-dimensional representations and discover how mathematics operates in three-dimensional settings. Pupils worked on designing software and three-dimensional printing. We collected data on how pupils and parents perceived the learning and teaching and how this influences the further thinking in mathematics. In a holistic approach, we aimed to identify how pupils, teachers and parents perceive the learning through these new technologies and how it affects the learning and teaching. Our research happened in onsite and remote teaching. In this conference, we will present results from the different studies, give insights into our research, and present future experimental investigations. [less ▲]

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See detailEthische Aspekte im reflexiven Schulpraktikum. Eine Ethik des Lebens für Praxisbegleiter
Weber, Jean-Marie UL

Scientific Conference (2020, July 03)

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See detailIntergenerational relations and the sense of belonging in the context of migration – What do second generation young adults learn from their first generation parents (and vice versa)?
Albert, Isabelle UL; Barros Coimbra, Stephanie UL

Scientific Conference (2020, July 02)

Migration is a life transition that entails changes in social and emotional belonging, and an important developmental task for migrants is the establishment of bonds in the receiving country. While first ... [more ▼]

Migration is a life transition that entails changes in social and emotional belonging, and an important developmental task for migrants is the establishment of bonds in the receiving country. While first generation immigrants have been enculturated in the culture of origin before being confronted with the host culture, their children grow up in two or multiple different value systems and cultures during their formative years. How does this so-called second-generation experience their cultural belonging and how are their identity constructions related to their parents’? This was a main topic of the FNR-funded IRMA project which compared first and second generations from Portuguese migrant families in the Luxembourgish multicultural context with regard to their cultural identity, intergenerational relations and transmission processes. The sample of the present study consists of family dyads resp. Triads comprising n = 70 PT mothers and n = 65 PT fathers over the age of 50 who arrived about 30 years ago to Luxembourg, together with n = 72 PT young adults (mean age M = 28. 2, SD = 7. 9; 61. 1% female) already born or grown up in Luxembourg. By use of a newly developed measure of cultural attachment to Luxembourg and Portugal, we examine the intergenerational continuity in the sense of cultural belonging and identify mediators in the transmission process such as relationship quality and the motivation to transmit or accept parental values. Results will be discussed with reference to an integrative model on intergenerational relations in the light of age and migration experiences. [less ▲]

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See detailCrossing borders – feeling connected? Exploring the sense of belonging
Murdock, Elke UL; Albert, Isabelle UL

Scientific Conference (2020, July 02)

Migrants find themselves living in a society with different practices, norms and values to their culture of origin. Migration is a life transition that entails changes in social and emotional belonging ... [more ▼]

Migrants find themselves living in a society with different practices, norms and values to their culture of origin. Migration is a life transition that entails changes in social and emotional belonging. This panel focuses on the question how migrants establish bonds in their receiving country. How do migrants negotiate their sense of belonging to the host and / or home country? What determines the strength of attachment to either of both? The present panel brings together researchers from three different countries who focus on the sense of belonging of different migrant populations. First, Isabelle Albert presents findings from a research project that examined intergenerational value transmission and cultural attachment to Portugal and Luxembourg among first and second-generation migrants in Luxembourg. Intergenerational relationships and migration are also the focus of Carlos Barros’ presentation. He presents findings from a qualitative study on intergenerational solidarity and maps solidarity patterns for different migrant groups. Jean Décieux presents identity constructions of international mobiles. The German Emigration and Remigration Panel study (GERPS) covers the migration trajectories of about 11,000 individuals. Patterns of belonging will be highlighted and discussed. Débora Maehler presents insights from a meta-analysis on the sense of belonging of young immigrants in Germany. Factors determining the strength of belonging to either their country of origin or Germany will be explored. The panel closes with a contribution by Elke Murdock on the host country perspective. She presents results from a quantitative study on criteria and predictors for the acceptance of new citizens as belonging by natives. [less ▲]

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See detailDo they belong? Perception of new citizens – a host country perspective
Murdock, Elke UL

Scientific Conference (2020, July 02)

In 30 years, Luxembourg’s population grew from 500,000 in 2010 to 614,000 in 2019. This growth is largely due to immigration. The foreign population percentage reached 47,5% on 1st of January 2019 – a ... [more ▼]

In 30 years, Luxembourg’s population grew from 500,000 in 2010 to 614,000 in 2019. This growth is largely due to immigration. The foreign population percentage reached 47,5% on 1st of January 2019 – a slight decline (-0.4%) on the previous year. This decline is in fact due to the rise in naturalizations. Since the reform of the citizenship law in 2008, Luxembourg has experienced a steady rise in naturalizations – which amounted to 684 in 2000, 4311 in 2010 and reached 11,876 in 2018. In terms of formal criteria, these new citizens belong to Luxembourg. They have to take part in parliamentary elections and can stand themselves as candidates. Yet how are these new Luxembourgish citizens perceived by the native population? Are they perceived as part of the in-group? To investigate this question, we conducted a quantitative study among 253 native Luxembourgers (65% women, Mage= 34.6, SD = 15.6) – all of whom held Luxembourgish citizenship and the majority (97%) were born in Luxembourg. We assessed the attitude towards a diverse society in general and Luxembourg in particular, adapted the allophilia scale to measure the positive attitude towards the outgroup new-Luxembourgers and assessed the perceived degree of overlap between native and new Luxembourgers. Just over half of the participants (57%) perceive a degree of overlap – which is in turn predicted by openness towards diversity and acceptance of new Luxembourgers. Implications of these findings for inclusive societies will be discussed. [less ▲]

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See detailNational responses to date during the COVID-19 crisis in the areas of migration and asylum
Sommarribas, Adolfo UL

Scientific Conference (2020, July 02)

This is a presentation of key findings of national responses to COVID-19 to date based on EMN Ad-hoc Queries launched by the European Migration Network between 13 March and 15 June 2020.

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See detailImmigration - the host country perspective
Murdock, Elke UL; Sölvason, Ómar

Scientific Conference (2020, July 01)

With 35.5 immigrants per 1000 inhabitants, Iceland had the third highest number of immigrants/ inhabitants in Europe in 2017. Until the turn of the century, the foreign population percentage in Iceland ... [more ▼]

With 35.5 immigrants per 1000 inhabitants, Iceland had the third highest number of immigrants/ inhabitants in Europe in 2017. Until the turn of the century, the foreign population percentage in Iceland was around 2%. In the last 5 years, this percentage has risen steadily to over 10% in 2018. How is this rapid rise in immigration experienced by the host country population? What is the attitude towards this increasingly plurally composed society? The Inclusive Societies – Iceland project investigated both, the immigrants’ situation in Iceland, but also the native populations’ attitude towards immigration and immigrants. It is important to take the host country perspective into consideration, as diversity ideologies will also determine the acculturation options for minorities. A quantitative survey was conducted among 3630 native Icelanders (51.1% women, Mean Age = 50.8, SD = 15.6), spread across all regions of Iceland. The questions covered satisfaction with life in Iceland in different domains but included also specific questions about the attitudes towards immigrants and enquired about contact with immigrants. The results indicate that this culture contact takes place – with over two thirds of participants indicating that they have invited immigrants to their home a few (34.4%) or many times (34.4%). Slightly less participants have been invited to immigrants’ homes (few times 33.6%, often 27.9%). Predictors for openness towards multiculturalism will be presented and discussed. We will also outline the domains with little and considerable variance among respondents concerning cultural practice and attitude to immigration and close with a discussion of policy implications. [less ▲]

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See detailConnecting the real world to mathematical models in elementary schools in Luxemburg
Haas, Ben; Kreis, Yves UL; Lavicza, Zsolt

in Proceedings of the British Society for Research into Learning Mathematics (2020, July), 40(2), 1-6

In the Luxemburgish national curriculum for elementary schools (MENFP, 2011) experimentations and discoveries of mathematics concepts in courses are strongly recommended. Elementary school teachers should ... [more ▼]

In the Luxemburgish national curriculum for elementary schools (MENFP, 2011) experimentations and discoveries of mathematics concepts in courses are strongly recommended. Elementary school teachers should engage students in active mathematical modelling approaches, where they can develop processes and content skills through discoveries. Moreover, learned skills should be connected to real-world problems and situations to foster a better understanding of students’ living environments. Nevertheless, this teaching culture in mathematics is unusual in elementary schools and teachers tend to teach based on textbooks. Students mostly learn mathematics by imitation and repetition rather than through modelling mathematics with real-world problems and situations. Thus, to develop new methodologies in teaching mathematics and to meet the requirements of the national curriculum, we designed different technology-enhanced teaching and learning methods to engage students in experimental approaches within and outside classrooms. Moreover, we conducted three studies with digital and physical modelling, augmented reality, and a tutoring system in elementary school mathematics courses. Based on our collected data, we identified settings and tasks likely to support active mathematical modelling approaches. [less ▲]

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See detailImproving open data accessibility through package development and community work
Kozlowski, Diego UL; Tiscornia, Pablo; Weksler, Guido et al

Poster (2020, July)

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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)

Detailed reference viewed: 69 (10 UL)