Elastography under uncertainty

Poster (2016, December 12)

Fractional charge oscillations in quantum spin Hall quantum dots

E-print/Working paper (2016)

We show that correlated two-particle backscattering can induce fractional charge oscillations in a quantum dot built at the edge of a two-dimensional topological insulator by means of magnetic barriers ... [more ▼]

We show that correlated two-particle backscattering can induce fractional charge oscillations in a quantum dot built at the edge of a two-dimensional topological insulator by means of magnetic barriers. The result nicely complements recent works where the fractional oscillations were obtained employing of semiclassical treatments. Moreover, since by rotating the magnetization of the barriers a fractional charge can be trapped in the dot via the Jackiw-Rebbi mechanism, the system we analyze offers the opportunity to study the interplay between this noninteracting charge fractionalization and the fractionalization due to two-particle backscattering. In this context, we demonstrate that the number of fractional oscillations of the charge density depends on the magnetization angle. Finally, we address the renormalization induced by two-particle backscattering on the spin density, which is characterized by a dominant oscillation, sensitive to the Jackiw-Rebbi charge, with a wavelength twice as large as the charge density oscillations. [less ▲]

Feedback trading and index option prices

Scientific Conference (2016, December 10)

Deep Learning on Big Data Sets in the Cloud with Apache Spark and Google TensorFlow

Scientific Conference (2016, December 09)

Machine learning is the branch of artificial intelligence giving computers the ability to learn patterns from data without being explicitly programmed. Deep Learning is a set of cutting-edge machine ... [more ▼]

Machine learning is the branch of artificial intelligence giving computers the ability to learn patterns from data without being explicitly programmed. Deep Learning is a set of cutting-edge machine learning algorithms that are inspired by how the human brain works. It allows to selflearn feature hierarchies from the data rather than modeling hand-crafted features. It has proven to significantly improve performance in challenging data analytics problems. In this tutorial, we will first provide an introduction to the theoretical foundations of neural networks and Deep Learning. Second, we will demonstrate how to use Deep Learning in a cloud using a distributed environment for Big Data analytics. This combines Apache Spark and TensorFlow, Google’s in-house Deep Learning platform made for Big Data machine learning applications. Practical demonstrations will include character recognition and time series forecasting in Big Data sets. Attendees will be provided with code snippets that they can easily amend in order to analyze their own data. A related, but shorter tutorial focusing on Deep Learning on a single computer was given at the Data Science Luxembourg Meetup in April 2016. It was attended by 70 people making it the most attended event of this Meetup series in Luxembourg ever since its beginning. [less ▲]

GNSS related periodic signals in coordinate time-series from Precise Point Positioning

in Geophysical Journal International (2016)

In Global Navigation Satellite System (GNSS) coordinate time series unrecognised errors and un-modelled (periodic) effects may bias non-linear motions induced by geophysical signals. Hence, understanding ... [more ▼]

In Global Navigation Satellite System (GNSS) coordinate time series unrecognised errors and un-modelled (periodic) effects may bias non-linear motions induced by geophysical signals. Hence, understanding and mitigating these errors is vital to reducing biases and on revealing subtle geophysical signals. To assess the nature of periodic signals in coordinate time series Precise Point Positioning (PPP) solutions for the period 2008 to 2015 are generated. The solu- tions consider Global Positioning System (GPS), GLObalnaya NAvigatsionnaya Sputnikovaya Sistema (GLONASS) or combined GPS+GLONASS (GNSS) observations. We assess the pe- riodic signals of station coordinates computed using the combined International GNSS Service (IGS) and four of its Analysis Centers (ACs) products. Furthermore, we make use of different filtering methods to investigate the sources of the periodic signals. A faint fortnightly signal in our PPP solution based on Jet Propulsion Laboratory (JPL) products and the existence of an 8-day period for those ACs generating combined GPS+GLONASS products are the main features in the GPS-only solutions. The existence of the 8-day period in the GPS-only solution indicates that GPS orbits computed in a combined GNSS solution contain GLONASS-specific signals. The GLONASS-only solution shows highly elevated powers at the 3rd draconitic harmonic ( ~ 120-day period), at the 8-day period and its harmonics (4 days, 2.67 days) besides the well-known annual, semi-annual and other draconitic harmonics. We show that the GLONASS constellation gaps before December 2011 contribute to the power at some of the frequencies. However, the well known fortnightly signal in GPS-only solutions is not discernible in the GLONASS-only solution. The combined GNSS solution contains periodic signals from both systems, with most of the powers being reduced when compared to the single-GNSS solutions. A 52% reduction for the horizontal components and a 36% reduction for the vertical compo- nent are achieved for the fortnightly signal from the GNSS solution compared to the GPS-only solution. Comparing the results of the employed filtering methods reveals that the source of most of the powers of draconitic and fortnightly signals are satellite-induced with a non-zero contribution of site-specific errors. [less ▲]

Social advance in interwar European borderlands. A compared analysis of elite training in Polish Upper Silesia and the Eupen-Malmedy region

Presentation (2016, December 08)

Espaces publics et mémoires à la frontière Serbie/Croatie : une illustration des tensions entre expressions nationalistes, oubli sélectif et banalité du quotidien

Scientific Conference (2016, December 08)

Une minorité de citoyens reste nostalgique

E-print/Working paper (2016)

Au cours de l’automne 1991, les républiques constituantes de l’Union soviétique proclamaient, l’une après l’autre, leur indépendance. Il y a 25 ans, avec la création de la Communauté des États ... [more ▼]

Au cours de l’automne 1991, les républiques constituantes de l’Union soviétique proclamaient, l’une après l’autre, leur indépendance. Il y a 25 ans, avec la création de la Communauté des États indépendants (CEI), la superpuissance URSS a cessé d’exister d’un jour à l’autre. Dr. Spero S.Z. Paravantis de l’Université du Luxembourg revient sur ce grand chapitre de l’histoire. [less ▲]

A tracking error control approach for model predictive position control of a quadrotor with time varying reference

in IEEE International Conference on Robotics and Biomimetics ROBIO, Qingdao, China, 2016 (2016, December 06)

In mobile robotic applications, a common problem is the following of a given trajectory with a constant velocity. Using standard model predictive control (MPC) for tracking of time varying trajectories ... [more ▼]

In mobile robotic applications, a common problem is the following of a given trajectory with a constant velocity. Using standard model predictive control (MPC) for tracking of time varying trajectories leads to a constant tracking error. This problem is modelled in this paper as quadrotor position tracking problem. The presented solution is a computationally light-weight target position control (T PC), that controls the tracking error of MPCs for constantly moving targets. The proposed technique is assessed mathematically in the Laplace domain, in simulation, as well as experimentally on a real quadrotor system. [less ▲]

Sustainable Economic and Monetary Union: the role of social rights

Scientific Conference (2016, December 06)

This paper focuses on one significant aspect of the sustainability of the EMU. it argues that social rights are key factors to support economic integration in the EU and in fine the overall European ... [more ▼]

This paper focuses on one significant aspect of the sustainability of the EMU. it argues that social rights are key factors to support economic integration in the EU and in fine the overall European integration process. [less ▲]