![]() Abraha, Kibrom Ebuy ![]() ![]() ![]() Poster (2016, December 12) 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. Those spurious ... [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. Those spurious signals can be caused either due to un-modelled long periodic signals or propagation of sub-daily signals into the time series. Understanding and mitigating these errors is vital to reduce biases and on revealing subtle geophysical signals. Mostly, the spurious signals are caused by unmodelled errors which occur due to the draconitic years, satellite ground repeats and absorption into resonant GNSS orbits. Accordingly, different features can be observed in GNSS-derived products from different single-GNSS or combined-GNSS solutions. To assess the nature of periodic signals on station coordinate time series Precise Point Positioning (PPP) solutions are generated using the Bernese GNSS Software V5.2. The solutions consider only GPS, only GLONASS or combined GPS+GLONASS (GNSS) observations. We assess the periodic signals of station coordinates computed using the combined International GNSS Service (IGS) and four of its Analysis Centers (ACs) products. [less ▲] Detailed reference viewed: 214 (26 UL)![]() Volp, Marcus ![]() ![]() Scientific Conference (2016, December 12) Intel SGX is the latest processor architecture promising secure code execution despite large, complex and hence potentially vulnerable legacy operating systems (OSs). However, two recent works identified ... [more ▼] Intel SGX is the latest processor architecture promising secure code execution despite large, complex and hence potentially vulnerable legacy operating systems (OSs). However, two recent works identified vulnerabilities that allow an untrusted management OS to extract secret information from Intel SGX's enclaves, and to violate their integrity by exploiting concurrency bugs. In this work, we re-investigate delayed preemption (DP) in the context of Intel SGX. DP is a mechanism originally proposed for L4-family microkernels as disable-interrupt replacement. Recapitulating earlier results on language-based information-flow security, we illustrate the construction of leakage-free code for enclaves. However, as long as adversaries have fine-grained control over preemption timing, these solutions are impractical from a performance/complexity perspective. To overcome this, we resort to delayed preemption, and sketch a software implementation for hypervisors providing enclaves as well as a hardware extension for systems like SGX. Finally, we illustrate how static analyses for SGX may be extended to check confidentiality of preemption-delaying programs. [less ▲] Detailed reference viewed: 363 (29 UL)![]() Hunegnaw, Addisu ![]() ![]() ![]() Poster (2016, December 12) In 2013 the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group (WG) started their reprocessing campaign, which proposes to re-analyze all relevant Global Positioning ... [more ▼] In 2013 the International GNSS Service (IGS) Tide Gauge Benchmark Monitoring (TIGA) Working Group (WG) started their reprocessing campaign, which proposes to re-analyze all relevant Global Positioning System (GPS) observations from 1995 to the end of 2013. This re-processed dataset will provide high quality estimates of land motions, enabling regional and global high-precision geophysical/geodetic studies. Several of the individual TIGA Analysis Centers (TACs) have completed processing the full history of GPS observations recorded by the IGS global network, as well as, many other GPS stations at or close to tide gauges, which are available from the TIGA data center at the University of La Rochelle (www.sonel.org). The TAC solutions contain a total of over 700 stations. This study focuses on the evaluations of any systematic error present in the three TIGA analysis center (TAC) SINEX solutions: the British Isles continuous GNSS Facility – University of Luxembourg consortium (BLT), the GeoForschungsZentrum (GFZ) Potsdam, and of the University of La Rochelle (ULR). We have analyzed the residual position time series of the individual TAC a combination of automatic and manual discontinuity identification, applying a post-seismic deformation model adopted from ITRF2014 for those stations that are affected by earthquakes, followed by the stacking of the daily solution of the individual TAC into a long term linear frame. We have carried out the error analysis using the Combination and Analysis of Terrestrial Reference Frame (CATREF) software package. The TIGA Combination Centre (TCC) at the University of Luxembourg (UL) is responsible for providing a combined solution with a global set of vertical land movement estimates. [less ▲] Detailed reference viewed: 221 (26 UL)![]() Wang, Jun ![]() in ICDM 2016 - IEEE International Conference on Data Mining series (ICDM) workshop CLOUDMINE (2016, December 12) Probabilistic graphic model is an elegant framework to compactly present complex real-world observations by modeling uncertainty and logical flow (conditionally independent factors). In this paper, we ... [more ▼] Probabilistic graphic model is an elegant framework to compactly present complex real-world observations by modeling uncertainty and logical flow (conditionally independent factors). In this paper, we present a probabilistic framework of neighborhood-based recommendation methods (PNBM) in which similarity is regarded as an unobserved factor. Thus, PNBM leads the estimation of user preference to maximizing a posterior over similarity. We further introduce a novel multi-layer similarity descriptor which models and learns the joint influence of various features under PNBM, and name the new framework MPNBM. Empirical results on real-world datasets show that MPNBM allows very accurate estimation of user preferences. [less ▲] Detailed reference viewed: 161 (10 UL)![]() Mavridis, Dimitrios ![]() Doctoral thesis (2016) Detailed reference viewed: 83 (14 UL)![]() Danescu, Elena ![]() Presentation (2016, December 12) One of the major research projects currently under way is dedicated to the European vocation and achievements of Pierre Werner, a former Prime Minister, Finance Minister and Foreign Minister of Luxembourg ... [more ▼] One of the major research projects currently under way is dedicated to the European vocation and achievements of Pierre Werner, a former Prime Minister, Finance Minister and Foreign Minister of Luxembourg, unanimously recognised as one of the architects of Economic and Monetary Union. The first stage of the research project particularly focuses on the plan for the establishment by stages of an economic and monetary union (more widely known as the Werner Report or the Werner Plan), drawn up by a group of experts chaired by Pierre Werner and officially presented on 8 October 1970 in Luxembourg. The project will then concentrate on the events that subsequently led to Economic and Monetary Union, as seen through the eyes of Pierre Werner and from the perspective of his own contribution; it will also examine a number of issues in which the former Luxembourg Prime Minister was particularly involved, such as the question of the seats of the institutions, the Luxembourg Compromise, the accession of the United Kingdom, and cooperation between the Benelux countries and the Belgo-Luxembourg Economic Union (BLEU). Project Manager: Dr Elena Danescu (elena.danescu@uni.lu) [less ▲] Detailed reference viewed: 108 (7 UL)![]() Bui, Huu Phuoc ![]() ![]() Poster (2016, December 12) Objective: To present the first real-time a posteriori error-driven adaptive finite element approach for real-time simulation and to demonstrate the method on a needle insertion problem. Methods: We use ... [more ▼] Objective: To present the first real-time a posteriori error-driven adaptive finite element approach for real-time simulation and to demonstrate the method on a needle insertion problem. Methods: We use corotational elasticity and a frictional needle/tissue interaction model based on friction. The problem is solved using finite elements within SOFA. The refinement strategy relies upon a hexahedron-based finite element method, combined with a posteriori error estimation driven local $h$-refinement, for simulating soft tissue deformation. Results: We control the local and global error level in the mechanical fields (e.g. displacement or stresses) during the simulation. We show the convergence of the algorithm on academic examples, and demonstrate its practical usability on a percutaneous procedure involving needle insertion in a liver. For the latter case, we compare the force displacement curves obtained from the proposed adaptive algorithm with that obtained from a uniform refinement approach. Conclusions: Error control guarantees that a tolerable error level is not exceeded during the simulations. Local mesh refinement accelerates simulations. Significance: Our work provides a first step to discriminate between discretization error and modeling error by providing a robust quantification of discretization error during simulations. [less ▲] Detailed reference viewed: 258 (20 UL)![]() Scuto, Denis ![]() Article for general public (2016) Detailed reference viewed: 97 (4 UL)![]() Lehnert, Thorsten ![]() Scientific Conference (2016, December 10) Detailed reference viewed: 50 (2 UL)![]() Wiegmann, Eva ![]() Speeches/Talks (2016) Detailed reference viewed: 81 (5 UL)![]() Glauner, Patrick ![]() ![]() 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 ▲] Detailed reference viewed: 539 (8 UL)![]() Abraha, Kibrom Ebuy ![]() ![]() ![]() 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 ▲] Detailed reference viewed: 341 (30 UL)![]() Weyer, Dany ![]() Presentation (2016, December 09) Detailed reference viewed: 106 (20 UL)![]() Weber, Jean-Marie ![]() Presentation (2016, December 08) Detailed reference viewed: 62 (2 UL)![]() Paravantis, Spero ![]() 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 ▲] Detailed reference viewed: 74 (7 UL)![]() Pigeron-Piroth, Isabelle ![]() in Revue Française de Socio-Economie (2016), 17(2nd semestre), 43-63 Within the Greater Region Saar-Lor-Lux (including one state: Luxembourg, and four regions: Saarland and Rhineland-Palatinate in Germany, Wallonia in Belgium and Lorraine in France), there is an increase ... [more ▼] Within the Greater Region Saar-Lor-Lux (including one state: Luxembourg, and four regions: Saarland and Rhineland-Palatinate in Germany, Wallonia in Belgium and Lorraine in France), there is an increase in the number of cross-border workers as well as a diversification of this form of employment, including temporary work. Temporary work agencies now constitute new employment intermediaries inside this cross-border area. They favour the development of specific forms of employment and take advantage of the differences in social and fiscal rules between countries. [less ▲] Detailed reference viewed: 215 (10 UL)![]() Blondel, Cyril ![]() Scientific Conference (2016, December 08) Detailed reference viewed: 73 (3 UL)![]() ![]() Derrmann, Thierry ![]() ![]() ![]() Poster (2016, December 08) Recent technological advances in communication technology have provided new ways to understand human mobility. Connected vehicles with their rising market penetration are particularly representative of ... [more ▼] Recent technological advances in communication technology have provided new ways to understand human mobility. Connected vehicles with their rising market penetration are particularly representative of this trend. They become increasingly interesting, not only as sensors, but also as participants in Intelligent Transportation System (ITS) applications. More specifically, their pervasive connectivity to cellular networks enables them as passive and active sensing units. In this paper, we introduce LuST-LTE, a package of open-source simulation tools that allows the simulation of vehicular traffic along with pervasive LTE connectivity. [less ▲] Detailed reference viewed: 273 (22 UL)![]() Venken, Machteld ![]() Presentation (2016, December 08) Detailed reference viewed: 24 (0 UL)![]() Kirsch, Claudine ![]() Scientific Conference (2016, December 07) Detailed reference viewed: 149 (6 UL) |
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