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See detailVoir Esch!
Scuto, Denis UL

Article for general public (2020)

Article on the publication of the "Guide historique et architectural Esch-sur-Alzette", City Guide of the capital of the former industrial basin of Luxembourg, European capital of culture 2022. Authors ... [more ▼]

Article on the publication of the "Guide historique et architectural Esch-sur-Alzette", City Guide of the capital of the former industrial basin of Luxembourg, European capital of culture 2022. Authors: Georges Buchler, Jean Goedert, Antoinette Lorang, Antoinette Reuter, Denis Scuto. Photographer: Christof Weber. [less ▲]

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See detailMuseums and power in the age of Covid-19
Brasseur, Laurence UL

Article for general public (2020)

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Peer Reviewed
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 detailLearning of Control Behaviours in Flying Manipulation
Manukyan, Anush UL

Doctoral thesis (2020)

Machine learning is an ever-expanding field of research with a wide range of potential applications. It has been increasingly used in different robotics tasks enhancing their autonomy and intelligent ... [more ▼]

Machine learning is an ever-expanding field of research with a wide range of potential applications. It has been increasingly used in different robotics tasks enhancing their autonomy and intelligent behaviour. This thesis presents how machine learning techniques can enhance the decision-making ability for control tasks in aerial robots as well as amplify the safety, thus broadly improving their autonomy levels. The work starts with the development of a lightweight approach for identifying degradations of UAV hardware-related components, using traditional machine learning methods. By analysing the flight data stream from a UAV following a predefined mission, it predicts the level of degradation of components at early stages. In that context, real-world experiments have been conducted, showing that such approach can be used as a safety system during different experiments, where the flight path of the vehicle is defined a priori. The next objective of this thesis is to design intelligent control policies for flying robots with highly nonlinear dynamics, operating in continuous state-action setting, using model-free reinforcement learning methods. To achieve this objective, first, the nuances and potentials of reinforcement learning have been investigated. As a result, numerous insights and strategies have been pointed out for crafting efficient reward functions that lead to successful learning performance. Finally, a learning-based controller is provided for controlling a hexacopter UAV with 6-DoF, to perform stable navigation and hovering actions by directly mapping observations to low-level motor commands. To increase the complexity of the given objective, the degrees of freedom of the robotic platform is upgraded to 7-DoF, using a flying manipulation as learning agent. In this case, the agent learns to perform a mission composed of take-off, navigation, hovering and end-effector positioning tasks. Later, to demonstrate the effectiveness of the proposed controller and its ability to handle higher number of degrees of freedom, the flying manipulation has been extended to a robotic platform with 8-DoF. To overcome several challenges of reinforcement learning, the RotorS Gym experimental framework has been developed, providing a safe and close to real simulated environment for training multirotor systems. To handle the increasingly growing complexity of learning tasks, the Cyber Gym Robotics platform has been designed, which extends the RotorS Gym framework by several core functionalities. For instance, it offers an additional mission controller that allows to decompose complex missions into several subtasks, thus accelerating and facilitating the learning process. Yet another advantage of the Cyber Gym Robotics platform is its modularity which allows to seamlessly switch both, learning algorithms as well as agents. To validate these claims, real-world experiments have been conducted, demonstrating that the model trained in the simulation can be transferred onto a real physical robot with only minor adaptations. [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 detail[GitHub] pilgun/acvcut: ACVCut 1.0
Pilgun, Aleksandr UL

Software (2020)

ACVCut shrinks Android apps towards executed code. The tool is based on ACVTool instruction coverage.

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See detail2 août 1980, 10.25 h
Scuto, Denis UL

Article for general public (2020)

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See detailData Analytics and Consensus Mechanisms in Blockchains
Feher, Daniel UL

Doctoral thesis (2020)

Blockchains, and especially Bitcoin have soared in popularity since their inceptions. This thesis furthers our knowledge of blockchains and their uses. First, we analyze transaction linkability in the ... [more ▼]

Blockchains, and especially Bitcoin have soared in popularity since their inceptions. This thesis furthers our knowledge of blockchains and their uses. First, we analyze transaction linkability in the privacy preserving cryptocurrency Zcash, based on the currency minting transactions (mining). Using predictable usage patterns and clustering heuristics on mining transactions, an attacker can link to publicly visible addresses in over 84% of the privacy preserving transactions. Then, we further analyze privacy issues for the privacy-oriented cryptocurrency Zcash. We study privacy preserving transactions and show ways to fingerprint user transactions, including active attacks. We introduce two new attacks, which we call the Danaan-gift attack and the Dust attack. Then, we investigate the generic landscape and hierarchy of miners as exemplified by Ethereum and Zcash. Both chains used application-specific integrated circuit (ASIC) resistant proofs-of-work which favor GPU mining in order to keep mining decentralized. This, however, has changed with the introduction of ASIC miners for these chains. This transition allows us to develop methods that might detect hidden ASIC mining in a chain (if it exists), and to study how the introduction of ASICs affects the decentralization of mining power. Finally, we describe how an attacker might use public blockchain information to invalidate miners' privacy, deducing the mining hardware of individual miners and their mining rewards. Then, we analyze the behavior of cryptocurrency exchanges on the Bitcoin blockchain, and compare the results to the exchange volumes reported by the same exchanges. We show, that in multiple cases these two values are close to each other, which confirms the integrity of their reported volumes. Finally, we present a heuristic to try to classify large clusters of addresses in the blockchain, and whether these clusters are controlled by an exchange. Finally, we describe how to couple reputation systems with distributed consensus protocols to provide a scalable permissionless consensus protocol with a low barrier of entry, while still providing strong resistance against Sybil attacks for large peer-to-peer networks of untrusted validators. We introduce the reputation module ReCon, which can be laid on top of various consensus protocols such as PBFT or HoneyBadger. The protocol takes external reputation ranking as input and then ranks nodes based on the outcomes of consensus rounds run by a small committee, and adaptively selects the committee based on the current reputation. [less ▲]

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See detailWhy is Germany not embracing the Humboldtian university?
Baker, David UL; Dusdal, Jennifer UL; Powell, Justin J W UL et al

Article for general public (2020)

Why is Germany not embracing the Humboldtian university? The focus on conducting research in independent institutes is holding the country back, say four academics.

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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 detailPre and post-treatments to improve weldability and mechanical properties of Aluminum-Polyamide laser welded specimens
Amne Elahi, Mahdi UL; Koch, Marcus; Heck, Mike et al

in Procedia CIRP (2020), 94

The laser polishing surface treatment is a prerequisite for enhanced weldability that is enabled by superior adhesion between the weldments. The paper describes the laser polishing process of the aluminum ... [more ▼]

The laser polishing surface treatment is a prerequisite for enhanced weldability that is enabled by superior adhesion between the weldments. The paper describes the laser polishing process of the aluminum surface to develop a relatively thick and porous artificial aluminum oxide layer. Microscopic observation shows the laser polishing process significantly improves the adhesion of molten polyamide to the aluminum surface. Besides, the shear load of the pretreated joints is much higher than that of as-received ones. However, for the majority of the welded samples, the failure happens at the polyamide near the interface of aluminum/polyamide due to the thermal effect and structural changes of polyamide during the welding process. By applying the post-treatment of the welded specimens with different cycles, the mentioned failure mechanism is not observed anymore. Therefore, the mechanical properties of the joint will be improved and reach to the limits of the base materials. [less ▲]

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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 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 detailMOMENT AND LONGITUDINAL RESISTANCE FOR COMPOSITE BEAMS BASED ON STRAIN LIMITED DESIGN METHOD
Zhang, Qingjie UL

Doctoral thesis (2020)

The bending and longitudinal shear design of composite beams of steel and concrete follows often the plastic design method, which is a simplification based on rectangle stress blocks. The application of ... [more ▼]

The bending and longitudinal shear design of composite beams of steel and concrete follows often the plastic design method, which is a simplification based on rectangle stress blocks. The application of the plastic design method requires cross-section to have enough rotation capacity allowing most parts of the critical cross-section reach plastic at failure. There are different types of compact composite beams, such as the slim-floor beams. For them, the neutral axis position often gets deeper at failure, which reduces the rotation capacity and brings questions to the bending resistance and longitudinal shear design according to the plastic design resistance. For a composite beam with deep neutral axis position, advanced numerical methods such as strain-limited design and FEM simulations can provide more accurate results than the plastic cross-section resistance. However, they are challenging to perform for general design engineers. In this work, simplified non-linear strain-limited design approaches, a strain-limited design software "SL.com" and an Abaqus add-in "CivilLab" have been developed to simplify the numerical calculations. They have also been applied in other chapters of this work to check the conventional plastic design results and to provide simplified design rules through parametric studies. With full shear connection, a deep neutral axis position in composite beam under sagging bending may cause an important part of the steel section not to reach plastic at concrete failure. In this case, plastic bending resistance calculated based on rectangle stress blocks can result in an overestimation of the resistance and therefore leads to unsafe design. Thus, according to EN1994-1-1 [22], a reduction factor β on plastic bending resistance (Mpl,Rd) needs to be applied for cross-sections with steel grade S420 and S460 and the relative compression zone height (zpl/h) is over 0.15. However, with the developments in industry as well as the second generation of Eurocode, this reduction factor still needs to be updated to consider new types of composite beams and wider ranges of steel grades. While the conventional plastic design method has its limitations and only applicable when the beam cross-section has enough rotation capacity to allow full plastic development, the more advanced strain-limited numerical calculation and FEM can be used for a much wider range regardless of the position of the neutral axis. The investigations in this dissertation through comparing the plastic bending resistance with advanced numerical calculation results, have confirmed that besides the cross-sections with high steel grades (S420, S460), also certain cross-sections with lower steel grades can have an overestimated plastic bending moment resistance. At least this effect is more important for compact cross-section types such as slim-floor sections or composite beams with asymmetrical structural steel profiles or with a small concrete slab effective width. Therefore vast amount of parametric studies based on strain-limited method and FEM have been developed to check the topics, such as limitation of plastic design methods for different types of composite beams. Furthermore new reduction β functions on Mpl,Rd for engineering practice considering much wider variates of composite beam cross-sections have been deviated. For the design with partial shear connection, the partial shear diagram developed based on plastic analysis has been widely used. As discussed above, the plastic design may not be suitable when the position of neutral axis is too deep, similar problems can occur for the partial shear diagram. This problem is especially significant for slim-floor beams, for which due to the compact cross-section, the relative compression zone height (zpl/h) is usually much higher than conventional composite beams. Thus the limitation of using the partial shear diagram for slim-floor beams is provided, and additional simplified engineering design rules are proposed. Plastic development inside the cross-section increases the longitudinal shear force in the plastic zones, furthermore with ductile shear connectors and respecting the minimum degree of shear connection, the non-linear redistribution of longitudinal shear force allows equal distance arrangement of shear connectors by the conventional design. For which, the full plastic development of the cross-section allowing plastic bending moment resistance and ductile shear connectors allowing non-linear longitudinal shear force distribution are the two fundamental conditions. The deep neutral axis position brings questions directly to the first assumption, as full plastic development of crosssection may not be able to reach. Thus the impact of a deep neutral axis position in the composite beams on longitudinal shear force distribution has been analysed. For which, the influence of plastic development inside beam cross-sections on longitudinal shear force with full shear interaction is theoretically explained. The different stages of nonlinear distribution of longitudinal shear force due to shear connectors are investigated through FEM parametric studies. Based on the theoretical and numerical calculation, the design suggestions of composite beams with deep neutral axis position are given. [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 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 detailVaria
Schafer, Valerie UL; Bahers, Jean-Baptiste

in Flux: Cahiers Scientifiques Internationaux Réseaux et Territoires (2020), 121

Coordination d'un numéro spécial Varia avec JB Bahers en tant que responsables de la rubrique Varia de Flux

Detailed reference viewed: 69 (1 UL)