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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 detailIntegration of time-series meta-omics data reveals how microbial ecosystems respond to disturbance
Herold, Malte; Martinez Arbas, Susana UL; Narayanasamy, Shaman et al

in Nature Communications (2020)

The development of reliable, mixed-culture biotechnological processes hinges on understanding how microbial ecosystems respond to disturbances. Here we reveal extensive phenotypic plasticity and niche ... [more ▼]

The development of reliable, mixed-culture biotechnological processes hinges on understanding how microbial ecosystems respond to disturbances. Here we reveal extensive phenotypic plasticity and niche complementarity in oleaginous microbial populations from a biological wastewater treatment plant. We perform meta-omics analyses (metagenomics, metatranscriptomics, metaproteomics and metabolomics) on in situ samples over 14 months at weekly intervals. Based on 1,364 de novo metagenome-assembled genomes, we uncover four distinct fundamental niche types. Throughout the time-series, we observe a major, transient shift in community structure, coinciding with substrate availability changes. Functional omics data reveals extensive variation in gene expression and substrate usage amongst community members. Ex situ bioreactor experiments confirm that responses occur within five hours of a pulse disturbance, demonstrating rapid adaptation by specific populations. Our results show that community resistance and resilience are a function of phenotypic plasticity and niche complementarity, and set the foundation for future ecological engineering efforts. [less ▲]

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See detailA scalable method to construct compact road networks from GPS trajectories
Guo, Yuejun UL; Bardera, Anton; FOrt, Marta et al

in International Journal of Geographical Information Science (2020), 0(0), 1-37

The automatic generation of road networks from GPS tracks is a challenging problem that has been receiving considerable attention in the last years. Although dozens of methods have been proposed, current ... [more ▼]

The automatic generation of road networks from GPS tracks is a challenging problem that has been receiving considerable attention in the last years. Although dozens of methods have been proposed, current techniques suffer from two main shortcomings: the quality of the produced road networks is still far from those produced manually, and the methods are slow, making them not scalable to large inputs. In this paper, we present a fast four-step density-based approach to construct a road network from a set of trajectories. A key aspect of our method is the use of an improved version of the Slide method to adjust trajectories to build a more compact density surface. The network has comparable or better quality than that of state-of-the-art methods and is simpler (includes fewer nodes and edges). Furthermore, we also propose a split-and-merge strategy that allows splitting the data domain into smaller regions that can be processed independently, making the method scalable to large inputs. The performance of our method is evaluated with extensive experiments on urban and hiking data. [less ▲]

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

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

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

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

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See 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 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 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 detailChapters on European and Comparative Consumer Law
Poillot, Elise UL

in Fenouillet, Dominique (Ed.) Dalloz Action - Droit de la consommation (2020)

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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 detailBetween Discretion and Proportionality: The Duty of Care in EU Judicial Review
Hofmann, Herwig UL

E-print/Working paper (2020)

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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 detailJoint Bit Allocation and Hybrid Beamforming Optimization for Energy Efficient Millimeter Wave MIMO Systems
Kaushik, Aryan; Vlachos, Evangelos; Tsinos, Christos et al

in IEEE Transactions on Green Communications and Networking (2020)

In this paper, we aim to design highly energy efficient end-to-end communication for millimeter wave multiple-input multiple-output systems. This is done by jointly optimizing the digital-to-analog ... [more ▼]

In this paper, we aim to design highly energy efficient end-to-end communication for millimeter wave multiple-input multiple-output systems. This is done by jointly optimizing the digital-to-analog converter (DAC)/analog-to-digital converter (ADC) bit resolutions and hybrid beamforming matrices. The novel decomposition of the hybrid precoder and the hybrid combiner to three parts is introduced at the transmitter (TX) and the receiver (RX), respectively, representing the analog precoder/combiner matrix, the DAC/ADC bit resolution matrix and the baseband precoder/combiner matrix. The unknown matrices are computed as a solution to the matrix factorization problem where the optimal fully digital precoder or combiner is approximated by the product of these matrices. A novel and efficient solution based on the alternating direction method of multipliers is proposed to solve these problems at both the TX and the RX. The simulation results show that the proposed solution, where the DAC/ADC bit allocation is dynamic during operation, achieves higher energy efficiency when compared with existing benchmark techniques that use fixed DAC/ADC bit resolutions. [less ▲]

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See detailARCH-COMP 2020 Category Report: Falsification
Ernst, Gidon; Arcaini, Paolo; Bennani, Ismail et al

in EPiC Series in Computing (2020)

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See detailNutrition and the 2020 Pandemic
Stover, Patrick; Balling, Rudolf UL

in Annual Review Of Nutrition (2020)

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See detailThe intergenerational transmission of wealth in rich countries
Nolan, Brian; Palomino, Juan; van Kerm, Philippe UL et al

Article for general public (2020)

Whether and how much intergenerational transfers contribute to wealth inequality is still subject to debate. This column analyses household survey data on inheritance and gifts inter vivos in France ... [more ▼]

Whether and how much intergenerational transfers contribute to wealth inequality is still subject to debate. This column analyses household survey data on inheritance and gifts inter vivos in France, Germany, Great Britain, Ireland, Italy, Spain, and the US to relate current household wealth levels and inequality to the receipt of intergenerational wealth transfers. In these countries, large transfers increase overall wealth inequality. Strengthening taxation capacity and instating lifetime capital acquisitions tax for gifts and inheritances may help counter the dis-equalising effect of intergenerational transfers. [less ▲]

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See detailDissipation-Time Uncertainty Relation
Falasco, Gianmaria UL; Esposito, Massimiliano UL

in Physical Review Letters (2020), 125(12), 120604

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See detailGround‐to‐GEO optical feeder links for very high throughput satellite networks: Accent on diversity techniques
Mengali, Alberto; Kourogiorgas, Charilaos; Lyras, Nikolaos et al

in International Journal of Satellite Communications and Networking (2020)

This paper studies the use of optical feeder links in very high throughput satellites (VHTS) networks with emphasis on gateway diversity techniques to mitigate the inherent propagation losses in optical ... [more ▼]

This paper studies the use of optical feeder links in very high throughput satellites (VHTS) networks with emphasis on gateway diversity techniques to mitigate the inherent propagation losses in optical frequencies. Focusing on a GEO scenario, the paper considers a system‐wide approach investigating various challenges of optical feeder links. These include transmission schemes amenable for transparent on‐board processing, optical channel models taking into account blockage by clouds and fading caused by atmospheric turbulence in addition to complexity of on‐board and on‐ground processing. The channel models are then used to dimension the ground segment towards ensuring a given availability percentage (e.g., 99.9%). The channel model and payload complexity further influence the choice of link layer techniques used for counteracting fading due to atmospheric turbulence in the absence of blockage. An elaborate end‐to‐end simulator incorporating the proposed channel models capturing the nuances of various processing blocks like optical‐electrical conversion is developed. The system performance results provide interesting insights and a framework for assessing the feasibility and advantages of optical feeder links in VHTS systems. [less ▲]

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See detailAb-initio calculation of muon spin polarization function to study lithium-ion diffusion in LiTi2O4 battery material
Suprayoga, E.; Rifai, A.; Subhan, A. et al

in AIP Conference Proceedings (2020), 2256(1), 030015

We report the study of lithium-ion diffusion in LiTi2O4 battery material by the analysis of muon spin polarization function at the muon site by DFT calculation. The important parameters which explain the ... [more ▼]

We report the study of lithium-ion diffusion in LiTi2O4 battery material by the analysis of muon spin polarization function at the muon site by DFT calculation. The important parameters which explain the lithium-ion diffusion will be derived from the function, including the field fluctuation rate and the local field distribution. The calculated results are shown in good agreement with the previously measured field distribution and the field fluctuation rate in LiTi2O4 at the ground state temperature. This method, therefore, may apply to the study of other battery materials. [less ▲]

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