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See detailLa référence à l’Alsace-Lorraine dans le rattachement et l’intégration d’Eupen-Malmedy à la Belgique (1918-1925)
Brüll, Christoph UL

Scientific Conference (2018, February 09)

En novembre 1910, le Journal des Tribunaux, principal organe d’information des juristes belges, qualifie la partie wallonne du Kreis allemand de Malmedy de « notre Alsace-Lorraine » où se trouveraient des ... [more ▼]

En novembre 1910, le Journal des Tribunaux, principal organe d’information des juristes belges, qualifie la partie wallonne du Kreis allemand de Malmedy de « notre Alsace-Lorraine » où se trouveraient des « frères de race et de langue, exilés et emprisonnés en Prusse. » Le 20 septembre 1920, ce Kreis ainsi que celui d’Eupen, presque exclusivement germanophone, sont rattachés à la Belgique, suite au traité de Versailles et à un simulacre de consultation populaire. Dans notre contribution qui traitera de la période qui s’étend de l’occupation de la région par des troupes belges en août 1919 à la fin du régime transitoire en mars 1925, nous voudrions nous interroger sur la signification de la référence à l’Alsace-Lorraine pendant cette phase du changement de la nationalité. Des indices donnent à penser que cette référence n’est pas limitée aux discours de légitimation de l’annexion du territoire par la Belgique, mais que les autorités belges ont, à certaines occasions (comme l’introduction du service militaire), contacté leurs homologues français afin de connaître la politique d’intégration menée en Alsace-Lorraine. En revanche, il n’y a jamais eu d’étude systématique de cette référence idéelle et pratique. Notre proposition voudrait combler cette lacune et constituerait également une contribution à une histoire comparée de la transition étatique dans les deux territoires. [less ▲]

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See detailSimulation-Based Fault Injection as a Verification Oracle for the Engineering of Time-Triggered Ethernet networks
Fejoz, Loïc; Regnier, Bruno; Miramont, Philippe et al

Scientific Conference (2018, February 02)

TTEthernet (TTE) is considered for use as high-speed backbone in the avionics of next-generation orbital space launchers. Given the key role of communication in launchers, the OEM must acquire a precise ... [more ▼]

TTEthernet (TTE) is considered for use as high-speed backbone in the avionics of next-generation orbital space launchers. Given the key role of communication in launchers, the OEM must acquire a precise understanding of TTE’s functioning and its performances in nominal and error conditions. This holds especially true for the clock synchronization algorithm, the cornerstone of time-triggered communication in TTE, which involves complex distributed algorithms. In this study, we use both an experimental platform and fault-injection on a simulation model to gain quantified insights in these questions. We first describe a fine-grained simulation model of TTE model and discuss how it has been validated against communication traces recorded on the TTE platform. We then present experiments that evaluate the accuracy of the clock synchronization in TTE in the fault-free case as well as considering permanent link failure and transient transmission errors. Finally, we discuss what we have learned during the project in terms of development process and programming language support for complex simulation models used in the design of critical systems. [less ▲]

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See detailInsights on the Performance and Configuration of AVB and TSN in Automotive Ethernet Networks
Migge, Jörn; Villanueva, Josetxo; Navet, Nicolas UL et al

Scientific Conference (2018, February 02)

Switched Ethernet is profoundly reshaping in-car communications. To meet the diverse real-time requirements in automotive communications, Quality-of-Service protocols that go beyond the mere use of ... [more ▼]

Switched Ethernet is profoundly reshaping in-car communications. To meet the diverse real-time requirements in automotive communications, Quality-of-Service protocols that go beyond the mere use of priorities are required. In this work, the basic questions that we investigate on a case-study with diverse and demanding communication requirements is what can we expect from the various protocols aimed at providing a better timing Quality of Service on top of Ethernet? And how to use them? Especially how to use them in a combined manner. We will focus on the Credit-Based Shaper of AVB, the Time-Aware Shaper of TSN and the use of priorities as defined in IEEE802.1Q. The performance metrics considered are the distributions of the communication latencies, obtained by simulation, as well as upper bounds on these quantities obtained by worst-case schedulability analysis. If there have been over the last 5 years numerous studies on the performance of AVB CBS, the literature on comparing AVB to TSN and other candidate protocols is still sparse. To the best of our knowledge, this empirical study is the first to consider most protocols currently considered in the automotive domain, with the aim to gain insights into the different technological, design and configurations alternatives. In particular, an objective of this study is to identify key problems that need to be solved in order to further automate network design and configuration. [less ▲]

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See detailThe Effects of Skills Underutilization and Unemployment on Hiring Decisions
Samuel, Robin UL; Sacchi, Stefan

Presentation (2018, January 23)

Research suggests negative effects of unemployment and skill underutilization on subsequent labor market outcomes. Among others, signaling theory has been used to explain why recruiters may evaluate ... [more ▼]

Research suggests negative effects of unemployment and skill underutilization on subsequent labor market outcomes. Among others, signaling theory has been used to explain why recruiters may evaluate competence and commitment of some job applicants less favorably than others. However, various country-, firm-, occupation-, and job-specific context factors may moderate such scarring effects. For example, a high youth unemployment rate may be associated with more scarring of previous unemployment spells and these effects might be different for occupations with different skill requirements. In this contribution, we explore the moderating role of transaction costs, i.e., the direct and indirect costs of recruiting and training new employees for scarring due to previous unemployment and skill underutilization. Furthermore, we investigate the extent to which the perceived difficulty of recruiting moderates these effects. Using data from a recent large-scale factorial survey of recruiters in four European countries (N~=~2,000) and employing multilevel linear regression models, we found, overall, scarring due to skill underutilization to exceed scarring due to unemployment. Skill underutilization was especially penalized when recruiting for a particular position was considered easy. Indirect transaction costs, particularly anticipated time required for organizational socialization, were negatively associated with unemployment scarring, but positively with scarring due to skill underutilization. Unemployment spells only had a negative effect on hiring chances, for jobs where there were monetary expenses for introductory trainings. Our findings constitute new evidence on the heterogeneity of scarring effects on hiring chances. We further contribute to the literature by highlighting the role of transaction costs and labor market performance. [less ▲]

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See detailThe Deformation Area Difference (DAD) method for condition assessment of reinforced structures
Erdenebat, Dolgion UL; Waldmann, Danièle UL; Scherbaum, Frank et al

in Engineering Structures (2018), 155

The investigation and condition assessment of bridges have a very high priority in the construction industry today. Particularly, due to the fact that many bridge structures are getting old and partly ... [more ▼]

The investigation and condition assessment of bridges have a very high priority in the construction industry today. Particularly, due to the fact that many bridge structures are getting old and partly reach the end of their useful life, the control and condition assessment of bridge structures have become very important and essential. The present research work introduces an efficient new method for condition assessment called the Deformation Area Difference (DAD) Method. This new method represents an attractive alternative to visual inspection and long-term monitoring. In this paper, the new method with its theoretical background is presented and explained by means of a laboratory experiment and some additional theoretical calculation examples. The experimental investigations have been realised on a reinforced concrete beam, which has been gradually loaded until failure. For each load step, the stiffness reduction and the apparent cracking have been monitored. High-precision measurements such as close-range photogrammetry, digital levelling and displacement sensors have been used for the determination of the deflection curve. The DAD method has been applied to identify the area of the crack pattern of the laboratory experiment. Furthermore, the method is discussed with regard to the load level and the precision of the deformation measurements. On the basis of the laboratory experiment, the applicability of the DAD method for damage detection could be proven. Furthermore, the sensitivity of the method with regard to the damage degree, the static system, the damage position and the impact of temperature variation were analysed. [less ▲]

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See detailBeware: Nobody Wants to Be Lonely
Tkalec, Igor UL

Article for general public (2018)

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See detailTransnational experiences, language competences and worldviews: contrasting language policies in two recently migrated Greek families in Luxembourg
Kirsch, Claudine UL; Gogonas, Nikos

in Multilingua (2018)

Against the backdrop of the ongoing crisis-led migration from Southern to Northwestern Europe, the present paper reports on a case study of two families who have recently migrated from Greece to ... [more ▼]

Against the backdrop of the ongoing crisis-led migration from Southern to Northwestern Europe, the present paper reports on a case study of two families who have recently migrated from Greece to Luxembourg. Luxembourg has a trilingual education system and many pupils of migrant background face difficulties on this account. Drawing on the framework of Family Language Policy, this paper explores the language ideologies and management strategies of two families as well as factors influencing their policies. This qualitative study was based on interviews, observations, and videos recorded by one of the families. The findings show that the families have contrasting language ideologies and management strategies that are informed by their differing transnational experiences, competences and worldviews. This study can contribute to a better understanding of the ways in which migrant families use their language resources in their new country. [less ▲]

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See detailSteuerrecht und Daten - Die virtuelle Betriebsstätte
Sinnig, Julia UL

Presentation (2018, January 12)

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See detailAttacks and Countermeasures for White-box Designs
Biryukov, Alex UL; Udovenko, Aleksei UL

E-print/Working paper (2018)

In the traditional symmetric cryptography, the adversary has access only to the inputs and outputs of a cryptographic primitive. In the white-box model the adversary is given full access to the ... [more ▼]

In the traditional symmetric cryptography, the adversary has access only to the inputs and outputs of a cryptographic primitive. In the white-box model the adversary is given full access to the implementation. He can use both static and dynamic analysis as well as fault analysis in order to break the cryptosystem, e.g. to extract embedded secret key. Implementations secure in such model have many applications in industry. However, creating such implementations turns out to be a very challenging if not an impossible task. Recently, Bos et al. proposed a generic attack on white-box primitives called differential computation analysis (DCA). This attack applies to most existent white-box implementations both from academia and industry. The attack comes from side-channel cryptanalysis method. The most common method protecting against such side-channel attacks is masking. Therefore, masking can be used in white-box implementations to protect against the DCA attack. In this paper we investigate this possibility and present multiple generic attacks against masked white-box implementations. We use the term “masking” in a very broad sense. As a result, we deduce new constraints that any secure white-box implementation must satisfy. We suggest partial countermeasures against the attacks. Some of our attacks were successfully applied to the WhibOx 2017 challenges. [less ▲]

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See detailSurmonter les barrières linguistiques avec « MaGrid » - un outil de formation de pré-mathématiques pour un contexte scolaire multilingue
Cornu, Véronique UL; Pazouki, Tahereh UL; Schiltz, Christine UL et al

Scientific Conference (2018, January 11)

Le contexte scolaire luxembourgeois est caractérisé par le multilinguisme et une population scolaire hétérogène, ce qui nécessite la mise en place de pratiques pédagogiques qui prennent en compte ... [more ▼]

Le contexte scolaire luxembourgeois est caractérisé par le multilinguisme et une population scolaire hétérogène, ce qui nécessite la mise en place de pratiques pédagogiques qui prennent en compte l’hétérogénéité des élèves. Dans le domaine des mathématiques, qui semble être non-verbal à première vue, des résultats scientifiques montrent que les enfants dont la langue maternelle est différente de la langue d’instruction, atteignent sur des tests d’aptitudes pré-mathématiques des résultats significativement inférieurs à ceux de leurs camarades natifs. Ceci est d’autant plus inquiétant, sachant que ces aptitudes pré-mathématiques sont prédictives des apprentissages ultérieurs. Par conséquent, nous avons développé l’outil de formation de pré-mathématiques non-verbale « MaGrid ». « MaGrid » permet à chaque enfant de bénéficier pleinement d’une instruction préscolaire en mathématiques, indépendamment de ses compétences langagières. Cet outil se caractérise par sa nature visuelle et il est implémenté sur tablette tactile. Jusqu’à présent, nous avons implémenté et évalué « MaGrid » lors de deux études scientifiques. Les résultats quantitatifs des évaluations empiriques sont prometteurs, comme ils montrent des effets positifs sur les habilités entraînées chez les enfants ayant utilisé cet outil comparé à un groupe contrôle. Dans une première étude, l’outil a été utilisé auprès de cinq classes durant 10 semaines, comprenant deux séances de 20 minutes par semaine. Les résultats lors de petites épreuves spécifiques ont été comparés aux résultats d’élèves de cinq classes n’ayant pas d’entraînement spécifique, et des effets d’intervention ont été observés. Dans une deuxième étude, nous nous sommes focalisés sur un groupe d’enfants de langue minoritaire (le portugais). « MaGrid » a été utilisé lors d’un programme d’intervention de pré-mathématiques s’étendant sur les deux années scolaires de l’école préscolaire. Les analyses préliminaires ont abouti à des résultats positifs. Des effets bénéfiques se sont manifestés sur différentes mesures de pré-mathématiques chez les enfants ayant suivi notre programme par rapport aux enfants du groupe contrôle. [less ▲]

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See detailTransforming Time Series for Efficient and Accurate Classification
Li, Daoyuan UL

Doctoral thesis (2018)

Time series data refer to sequences of data that are ordered either temporally, spatially or in another defined order. They can be frequently found in a variety of domains, including financial data ... [more ▼]

Time series data refer to sequences of data that are ordered either temporally, spatially or in another defined order. They can be frequently found in a variety of domains, including financial data analysis, medical and health monitoring and industrial automation applications. Due to their abundance and wide application scenarios, there has been an increasing need for efficient machine learning algorithms to extract information and build knowledge from these data. One of the major tasks in time series mining is time series classification (TSC), which consists of applying a learning algorithm on labeled data to train a model that will then be used to predict the classes of samples from an unlabeled data set. Due to the sequential characteristic of time series data, state-of-the-art classification algorithms (such as SVM and Random Forest) that performs well for generic data are usually not suitable for TSC. In order to improve the performance of TSC tasks, this dissertation proposes different methods to transform time series data for a better feature extraction process as well as novel algorithms to achieve better classification performance in terms of computation efficiency and classification accuracy. In the first part of this dissertation, we conduct a large scale empirical study that takes advantage of discrete wavelet transform (DWT) for time series dimensionality reduction. We first transform real-valued time series data using different families of DWT. Then we apply dynamic time warping (DTW)-based 1NN classification on 39 datasets and find out that existing DWT-based lossy compression approaches can help to overcome the challenges of storage and computation time. Furthermore, we provide assurances to practitioners by empirically showing, with various datasets and with several DWT approaches, that TSC algorithms yield similar accuracy on both compressed (i.e., approximated) and raw time series data. We also show that, in some datasets, wavelets may actually help in reducing noisy variations which deteriorate the performance of TSC tasks. In a few cases, we note that the residual details/noises from compression are more useful for recognizing data patterns. In the second part, we propose a language model-based approach for TSC named Domain Series Corpus (DSCo), in order to take advantage of mature techniques from both time series mining and Natural Language Processing (NLP) communities. After transforming real-valued time series into texts using Symbolic Aggregate approXimation (SAX), we build per-class language models (unigrams and bigrams) from these symbolized text corpora. To classify unlabeled samples, we compute the fitness of each symbolized sample against all per-class models and choose the class represented by the model with the best fitness score. Through extensive experiments on an open dataset archive, we demonstrate that DSCo performs similarly to approaches working with original uncompressed numeric data. We further propose DSCo-NG to improve the computation efficiency and classification accuracy of DSCo. In contrast to DSCo where we try to find the best way to recursively segment time series, DSCo-NG breaks time series into smaller segments of the same size, this simplification also leads to simplified language model inference in the training phase and slightly higher classification accuracy. The third part of this dissertation presents a multiscale visibility graph representation for time series as well as feature extraction methods for TSC, so that both global and local features are fully extracted from time series data. Unlike traditional TSC approaches that seek to find global similarities in time series databases (e.g., 1NN-DTW) or methods specializing in locating local patterns/subsequences (e.g., shapelets), we extract solely statistical features from graphs that are generated from time series. Specifically, we augment time series by means of their multiscale approximations, which are further transformed into a set of visibility graphs. After extracting probability distributions of small motifs, density, assortativity, etc., these features are used for building highly accurate classification models using generic classifiers (e.g., Support Vector Machine and eXtreme Gradient Boosting). Based on extensive experiments on a large number of open datasets and comparison with five state-of-the-art TSC algorithms, our approach is shown to be both accurate and efficient: it is more accurate than Learning Shapelets and at the same time faster than Fast Shapelets. Finally, we list a few industrial applications that relevant to our research work, including Non-Intrusive Load Monitoring as well as anomaly detection and visualization by means for hierarchical clustering for time series data. In summary, this dissertation explores different possibilities to improve the efficiency and accuracy of TSC algorithms. To that end, we employ a range of techniques including wavelet transforms, symbolic approximations, language models and graph mining algorithms. We experiment and evaluate our approaches using publicly available time series datasets. Comparison with the state-of-the-art shows that the approaches developed in this dissertation perform well, and contribute to advance the field of TSC. [less ▲]

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See detailA Multiscale DEM-VOF Method for the simulation of three-phase flows
Pozzetti, Gabriele UL; Peters, Bernhard UL

in International Journal of Multiphase Flow (2018), 99

A novel multiscale approach for three-phase flows is presented. The goal of the proposed method is to solve arbitrary three-phase flow configurations in a computationally efficient way, and in particular ... [more ▼]

A novel multiscale approach for three-phase flows is presented. The goal of the proposed method is to solve arbitrary three-phase flow configurations in a computationally efficient way, and in particular taking into account the effects of different length scales while sharply reducing the computational burden. This is particularly important in chemical, environmental, and process engineering, where large-scale quantities are normally of interest, but small-scale dynamics cannot be neglected. The method is based on the definition of two different length scales: the bulk scale, and the fluid fine scale. A dual-grid approach is adopted in order to resolve the bulk scale with information from the fluid fine scale. It is shown that the described method succeeds in delivering more accuracy than a standard approach based on the volume averaging technique, still, it remains suitable for the solution of real interest problems. The method is shown to successfully satisfy experimental results presented in the literature. Examples of three-phase flows simulations are provided to show how the proposed numerical approach can describe the physics of particle-laden, free surface flows with competitive computational cost. It is shown how the proposed method can naturally extend the DEM-VOF method to the presence of complex interface dynamics. [less ▲]

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See detailHistoriker und die Konstruktion von Zeitgenossenschaft. Eine Projektskizze am Beispiel der Militärverwaltung Belgien-Nordfrankreich im Zweiten Weltkrieg
Brüll, Christoph UL

Presentation (2018, January 09)

Gegenstand des Projekts ist die Konstruktion des Zeitzeugendiskurses mehrerer führender Mitglieder der deutschen Militärverwaltung in Brüssel. Arbeitshypothese ist, dass die Konstruktion in drei Phasen ... [more ▼]

Gegenstand des Projekts ist die Konstruktion des Zeitzeugendiskurses mehrerer führender Mitglieder der deutschen Militärverwaltung in Brüssel. Arbeitshypothese ist, dass die Konstruktion in drei Phasen verlief: Der „Generalprozess“ (1950-1951) gegen Alexander von Falkenhausen und Eggert Reeder (gefolgt von einer Reihe anderer Prozesse bis in die 1980er Jahre hinein). Die Legitimierungs- und Verteidigungsdiskurse einiger Akteure gegenüber Anschuldigungen, die ihre Tätigkeiten während des Krieges betrafen. Ihre Tätigkeit als Zeitzeuge für belgische und deutsche Historiker und Journalisten seit den 1970er Jahren. [less ▲]

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See detailGradient Estimates on Dirichlet and Neumann Eigenfunctions
Arnaudon, Marc; Thalmaier, Anton UL; Wang, Feng-Yu

E-print/Working paper (2018)

By methods of stochastic analysis on Riemannian manifolds, we derive explicit two-sided gradient estimates for Dirichlet eigenfunctions on a d-dimensional compact Riemannian manifold D with boundary ... [more ▼]

By methods of stochastic analysis on Riemannian manifolds, we derive explicit two-sided gradient estimates for Dirichlet eigenfunctions on a d-dimensional compact Riemannian manifold D with boundary. Corresponding two-sided gradient estimates for Neumann eigenfunctions are derived in the second part of the paper. [less ▲]

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See detailProceedings - 2017 ILILAS Distinguished Lectures
Bouvry, Pascal UL; Bisdorff, Raymond; Schommer, Christoph UL et al

Report (2018)

The Proceedings summarizes the 12 lectures that have taken place within the ILIAS Dinstguished Lecture series 2017. It contains a brief abstract of the talks as well as some additional information about ... [more ▼]

The Proceedings summarizes the 12 lectures that have taken place within the ILIAS Dinstguished Lecture series 2017. It contains a brief abstract of the talks as well as some additional information about each speaker. [less ▲]

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See detailBrexit Seen from Luxembourg
Högenauer, Anna-Lena UL

E-print/Working paper (2018)

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See detailThe Temporary Reintroduction of Border Controls Inside the Schengen Area: Towards a Spatial Perspective
Evrard, Estelle UL; Nienaber, Birte UL; Sommarribas, Adolfo UL

in Journal of Borderlands Studies (2018)

Following the terrorist attacks in Paris (November 2015) and Brussels (March 2016), several EU Member States have decided to re-establish border controls or to build walls inside the Schengen Area ... [more ▼]

Following the terrorist attacks in Paris (November 2015) and Brussels (March 2016), several EU Member States have decided to re-establish border controls or to build walls inside the Schengen Area. Although these decisions are temporary and legally framed by the Schengen code, their extent disrupts the free movement within the Schengen Area, in particular in border areas. While lawyers and economists have analyzed the impacts of this situation, the spatial perspective has remained rather neglected. This exploratory contribution aims to address this gap in the literature by outlining the spatial significance of reintroduced controls for border areas inside the Schengen Area. This contribution firstly undertakes a literature review of the different conceptual tools at hand. These are then compared with a set of exploratory empirical materials. The article focuses more precisely on the Greater Region where France and Germany have reintroduced border controls, thus disrupting in particular daily cross-border flows with Luxembourg and Belgium. The analysis demonstrates that the border acts as a filter, disrupting cross-border flows and cooperation. Also, it sheds some light on the important role played by the ideational perception of the border for practitioners and decision-makers. This contribution concludes by suggesting several paths for a future research agenda. [less ▲]

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