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See detailIntegrated micromechanical model for slope stability analysis
Kabore, Brice Wendlassida UL; Peters, Bernhard UL

Scientific Conference (2019, April 09)

Advances in supercomputing hardware have made it possible to handle highly complex geomechanical analysis with large data. Thus, particle-based methods are gaining an ever-increasing interest with ... [more ▼]

Advances in supercomputing hardware have made it possible to handle highly complex geomechanical analysis with large data. Thus, particle-based methods are gaining an ever-increasing interest with massively parallel programs being developed. These methods have been applied to the analysis of failure mechanisms and scenarios such as mass movement in landslides, avalanches under static, dynamic or seismic loading condition. They provide deep insights into the meso and micro-scale mechanisms leading to macroscopic instabilities. This contribution describes a micromechanical model for stability analysis and simulation in natural or man-made slopes under complex loading and boundary conditions. Based on the micromechanics of loose granular and compacted geomaterial, microstructural change, viscoelastic deformations, fracture, and healing are explicitly integrated into a coupled discrete particle and beam lattice model. Stress-based failure criteria and energy based dissipation and frictional contact are employed. Both gravity increase and strength reduction methods have been employed to evaluate the Factor of Safety (FoS) and potential failure surface and compared. With an emphasis on the impact of the microstructure and its spatial variability on stress-induced microcracks and crack propagation, this study outlines material models and properties relevant to stability analysis. Special focus has been put on layered slopes which present varying shear strength along the depth formed over time according to pressure, temperature, and moisture such as snowpack. This microstructural approach unifies geometrical and material information and allows the structural assembling layers of different strength. [less ▲]

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See detailAn interface resolved immersed boundary method in XDEM for particulate flow simulations
Wu, Mingqiu UL; Peters, Bernhard UL; Rosemann, Tony et al

in International Congress on Particle Technology (2019, April 09)

immersed boundary method (IBM) has recently been used for particulate flows and complex fluid-solid interaction problems. The IBM was first introduced by Peskin to simulate blood flow in a beating heart ... [more ▼]

immersed boundary method (IBM) has recently been used for particulate flows and complex fluid-solid interaction problems. The IBM was first introduced by Peskin to simulate blood flow in a beating heart. Later it has been extended for a different range of applications. The advantages of IBM over the body-fitted method is that it substantially simplified grid generation for immersed geometries, and it is easier to handle moving boundary situations. IBM even allows the use of a stationary and non-deformation background mesh, as well as it reduces the cost of computation by avoiding generation of a body-fitted mesh for each time step. However, the IBM approach is not straightforward to implement and it requires special techniques for cut-off boundary cells as well as special techniques for data point interpolations. Generally, the IBM is classified into two approaches based on the methods of imposing the boundary condition in the immersed body. The first approach is called fictitious domain method with continuous forcing scheme which employs a distributed forcing function to impose a rigidity boundary condition in the solid particle domain. The second one is the discrete forcing approach, which enables a sharp interface to represent the immersed surface. The IBM discussed in this work is a combination of these above two approaches: we first employ the continuous forcing scheme to get a first-step approximation of the immersed body, then use an interpolation polynomial to impose a desired accurate physical boundary for each immersed boundary point based on a least square interpolation reconstruction scheme. Particle motions can be calculated and tracked by solving Newton’s equations of motions using the extended discrete element method (XDEM) while the data of fluid flow properties are obtained by solving the Navier-Stokes equations which govern the fluid phase. Combined this leads to the basic concept of DEM-CFD coupling. Therefore, a particle interface resolved simulation solver is developed by coupling the XDEM and IBM approaches together. Consequently, this solver is then used to handle both static and dynamic particle problems as well as particle packed bed simulations. The validation of the solver can be performed by setting one static sphere in a channel and evaluate the drag coefficients and Strouhal number (when shedding occurs) at various Reynolds [less ▲]

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See detailImproved Monitoringand Tracking Hurricanes using GPS Atmospheric WaterVapour
Ejigu, Yohannes Getachew; Teferle, Felix Norman UL; klose, Anna et al

Poster (2019, April 09)

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See detailAn Effective Hybrid Imperialist Competitive Algorithm and Tabu Search for an Extended Flexible Job Shop Scheduling Problem
Tessaro Lunardi, Willian UL; Voos, Holger UL; Cherri, Luiz Henrique

in 34th ACM/SIGAPP Symposium On Applied Computing, Limassol, Cyprus April 8-12, 2019 (2019, April 08)

An extended version of the flexible job shop problem is tackled in this work. The investigated extension of the classical flexible job shop problem allows the precedences between the operations to be ... [more ▼]

An extended version of the flexible job shop problem is tackled in this work. The investigated extension of the classical flexible job shop problem allows the precedences between the operations to be given by an arbitrary directed acyclic graph instead of a linear order. The problem consists of designating the operations to the machines and sequencing them in compliance with the supplied precedences. The goal in the present work is the minimization of the makespan. In order to produce reasonable outcomes in acceptable time, a hybrid imperialist competitive algorithm and tabu search is proposed to solve the problem. Numerical experiments assess the efficiency of the proposed method and compare it with well-known scheduling algorithms. [less ▲]

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See detailLa Metzeschmelz, quelle histoire!
Scuto, Denis UL; Maas, Jacques

Article for general public (2019)

This article gives an overview (with illustrations) of the history of steel factory "Metzeschmelz" founded in 1871 (renamed Arbed Esch in 1911 and ArcelorMittal Esch-Schifflange in 2007). The steel ... [more ▼]

This article gives an overview (with illustrations) of the history of steel factory "Metzeschmelz" founded in 1871 (renamed Arbed Esch in 1911 and ArcelorMittal Esch-Schifflange in 2007). The steel factory was closed down in 2012. The industrial wasteland will be transformed in a new quarter of the city of Esch-sur-Alzette in Luxembourg (capital of the south region). [less ▲]

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See detailMortgages and Life Time Contracts
Ratti, Luca UL

Scientific Conference (2019, April 05)

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See detailHistorische Karten aus der Maas-Mosel-Region - Analysemethoden zur Komplexität historischer Grenzen in der Praxis
Uhrmacher, Martin UL

Presentation (2019, April 05)

Grenzen auf historischen Karten sind stets Ausdruck eines Machtanspruchs, den sie räumlich darstellen. Sie bringen den Zusammenhang zwischen Kartographischer und realer Macht in Form von Punkten, Strichen ... [more ▼]

Grenzen auf historischen Karten sind stets Ausdruck eines Machtanspruchs, den sie räumlich darstellen. Sie bringen den Zusammenhang zwischen Kartographischer und realer Macht in Form von Punkten, Strichen oder Linien gewissermaßen auf das Blatt. Kartographie und Grenzen gehören deshalb im Kontext der Territorialpolitik auch untrennbar zusammen. Karten dienen einerseits nach innen einer möglichst präzisen Raumerfassung und somit als wichtige Informationsquelle und Orientierungshilfe für den Landesherrn. Gleichzeitig werden sie aber auch nach außen als Mittel politischer Propaganda und zur Durchsetzung von territorialen Ansprüchen gebraucht. Durch die Analyse kartographischer Quellen wird eine tiefergehende Annäherung an die Charakteristik und Ausprägung von Grenzräumen versucht. Dazu werden exemplarisch zwei Grenzregionen in den Blick genommen: Zum einen die luxemburgisch-französische Grenze des 17. und 18. Jahrhunderts sowie die kurtrierisch-luxemburgische Grenze im späten 18. Jahrhundert. Wie lassen sich Grenzen in dieser Zeit definieren und welche Funktion spielten Karten bei ihrer Festlegung, Ausprägung und Durchsetzung? [less ▲]

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See detailKartographische Ressourcen im Internet, ein Überblick
Uhrmacher, Martin UL

Presentation (2019, April 05)

Detailed reference viewed: 35 (1 UL)
See detailGoogle My Maps: Ein Tool für die Erstellung einfacher historischer Karten
Uhrmacher, Martin UL

Presentation (2019, April 05)

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See detailAsset Pricing Implications of Good Governance
Lehnert, Thorsten UL

in PLoS ONE (2019), 14 (4)(e0214930), 1-14

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See detailDesign and Cryptanalysis of Symmetric-Key Algorithms in Black and White-box Models
Udovenko, Aleksei Nikolaevich UL

Doctoral thesis (2019)

Cryptography studies secure communications. In symmetric-key cryptography, the communicating parties have a shared secret key which allows both to encrypt and decrypt messages. The encryption schemes used ... [more ▼]

Cryptography studies secure communications. In symmetric-key cryptography, the communicating parties have a shared secret key which allows both to encrypt and decrypt messages. The encryption schemes used are very efficient but have no rigorous security proof. In order to design a symmetric-key primitive, one has to ensure that the primitive is secure at least against known attacks. During 4 years of my doctoral studies at the University of Luxembourg under the supervision of Prof. Alex Biryukov, I studied symmetric-key cryptography and contributed to several of its topics. Part I is about the structural and decomposition cryptanalysis. This type of cryptanalysis aims to exploit properties of the algorithmic structure of a cryptographic function. The first goal is to distinguish a function with a particular structure from random, structure-less functions. The second goal is to recover components of the structure in order to obtain a decomposition of the function. Decomposition attacks are also used to uncover secret structures of S-Boxes, cryptographic functions over small domains. In this part, I describe structural and decomposition cryptanalysis of the Feistel Network structure, decompositions of the S-Box used in the recent Russian cryptographic standard, and a decomposition of the only known APN permutation in even dimension. Part II is about the invariant-based cryptanalysis. This method became recently an active research topic. It happened mainly due to recent extreme cryptographic designs, which turned out to be vulnerable to this cryptanalysis method. In this part, I describe an invariant-based analysis of NORX, an authenticated cipher. Further, I show a theoretical study of linear layers that preserve low-degree invariants of a particular form used in the recent attacks on block ciphers. Part III is about the white-box cryptography. In the white-box model, an adversary has full access to the cryptographic implementation, which in particular may contain a secret key. The possibility of creating implementations of symmetric-key primitives secure in this model is a long-standing open question. Such implementations have many applications in industry; in particular, in mobile payment systems. In this part, I study the possibility of applying masking, a side-channel countermeasure, to protect white-box implementations. I describe several attacks on direct application of masking and provide a provably-secure countermeasure against a strong class of the attacks. Part IV is about the design of symmetric-key primitives. I contributed to design of the block cipher family SPARX and to the design of a suite of cryptographic algorithms, which includes the cryptographic permutation family SPARKLE, the cryptographic hash function family ESCH, and the authenticated encryption family SCHWAEMM. In this part, I describe the security analysis that I made for these designs. [less ▲]

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See detailParis and Nice terrorist attacks: Exploring Twitter and web archives
Schafer, Valerie UL; Truc, Gérôme; Badouard, Romain et al

in Media, War and Conflict (2019)

The attacks suffered by France in January and November 2015, and then in the course of 2016, especially the Nice attack, provoked intense online activity both during the events and in the months that ... [more ▼]

The attacks suffered by France in January and November 2015, and then in the course of 2016, especially the Nice attack, provoked intense online activity both during the events and in the months that followed. The digital traces left by this reactivity and reactions to events gave rise, from the very first days and even hours after the attacks, to a ‘real-time’ institutional archiving by the National Library of France (Bibliothèque nationale de France, BnF) and the National Audio-visual Institute (Institut national de l’audiovisuel, Ina). The results amount to millions of archived tweets and URLs. This article sets out to explore the creation and the temporalities of this ‘born-digital’ heritage. It seeks to highlight the most significant issues guiding initial research carried out on these relatively unedited corpora, from collection to exploitation, online stream of data to its mediation and re-composition. [less ▲]

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See detailSearching bodies through born-digital heritage: issues and challenges
Schafer, Valerie UL

Presentation (2019, April 03)

This presentation, followed by a hands-on session, will present several methods, issues and challenges that researchers may face when they analyse web archives and give a few examples more specifically ... [more ▼]

This presentation, followed by a hands-on session, will present several methods, issues and challenges that researchers may face when they analyse web archives and give a few examples more specifically dedicated to the histories of healthy bodies. [less ▲]

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See detailHemap: An nteractive online resource for characterizing molecular phenotypes across hematologic malignancies
Pölönen, Petri; Mehtonen, Juha; Lin, Jake et al

in Cancer Research (2019)

Large collections of genome-wide data can facilitate the characterization of disease states and subtypes, permitting pan-cancer analysis of molecular phenotypes and evaluation of disease contexts for new ... [more ▼]

Large collections of genome-wide data can facilitate the characterization of disease states and subtypes, permitting pan-cancer analysis of molecular phenotypes and evaluation of disease contexts for new therapeutic approaches. We analyzed 9,544 transcriptomes from over 30 hematologic malignancies, normal blood cell types and cell lines, and show that the disease types can be stratified in a data-driven manner. We utilized the obtained molecular clustering for discovery of cluster-specific pathway activity, new biomarkers and in silico drug target prioritization through integration with drug target databases. Using known vulnerabilities and available drug screens in benchmarking, we highlight the importance of integrating the molecular phenotype context and drug target expression for in silico prediction of drug responsiveness. Our analysis implicates BCL2 expression level as important indicator of venetoclax responsiveness and provides a rationale for its targeting in specific leukemia subtypes and multiple myeloma, links several polycomb group proteins that could be targeted by small molecules (SFMBT1, CBX7 and EZH1) with CLL, and supports CDK6 as disease-specific target in AML. Through integration with proteomics data, we characterized target protein expression for pre-B leukemia immunotherapy candidates, including DPEP1. These molecular data can be explored using our freely available interactive resource, Hemap, for expediting therapeutic innovations in hematologic malignancies. [less ▲]

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See detail[Rezension] Lars Nowak (Hg.): Medien - Krieg - Raum
Pause, Johannes UL

in MEDIENwissenschaft: Rezensionen, Reviews (2019), 1(2019), 24-27

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See detailThe democratic deficit and European Central Bank crisis monetary policies.
Högenauer, Anna-Lena UL; Howarth, David UL

in Maastricht Journal of European and Comparative Law (2019)

This article presents the argument that European Central Bank (ECB) policy-making from the start of the sovereign debt crisis in 2010 undermined the democratic legitimacy of the ECB. We start with the ... [more ▼]

This article presents the argument that European Central Bank (ECB) policy-making from the start of the sovereign debt crisis in 2010 undermined the democratic legitimacy of the ECB. We start with the argument – defended by a number of scholars including Majone and Moravcsik – that where European Union (EU) policy-making is technocratic and does not have significant redistributive implications it can benefit from depoliticization that does not undermine the democratic legitimacy of this policy-making. This is notably the case where EU institutions have narrow mandates and are constrained by super-majoritarian decision-making. Prior to the international financial crisis, the ECB’s monetary policies were shaped entirely by the interpretation that its mandate was primarily to ensure low inflation. From the outbreak of the sovereign debt crisis, the ECB adopted a range of policies which pushed its role well beyond that interpretation and engaged in a form of redistribution that directly undermined treaty provisions. [less ▲]

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See detailLËTZEBUERGER MUSEK AM 19. JOERHONNERT
Sagrillo, Damien UL

Conference given outside the academic context (2019)

Musikhistoriographie ist vielschichtig. Die Geschichtsschreibung über Musik in Luxemburg gliedert sich in verschiedene Teilaspekte. Zunächst ist sie Teil regionaler Musikforschung in Europa und zudem, was ... [more ▼]

Musikhistoriographie ist vielschichtig. Die Geschichtsschreibung über Musik in Luxemburg gliedert sich in verschiedene Teilaspekte. Zunächst ist sie Teil regionaler Musikforschung in Europa und zudem, was Luxemburg betrifft, nationale Musikforschung. Ein erster Blickwinkel ist der musikethnologische: Ein Volk, eine Nation hat seine/ihre Lieder, die in ihm/ihr entstehen, aufgenommen, mündlich über Landes- sowie Sprachgrenzen und über Generationen überliefert werden. Volkstümliche Lieder schauen dem Volk „auf’s Maul“, sind Volksliedern nachempfunden, stammen aus der Feder von Komponisten und sind – zumindest auf Luxemburg bezogen – patriotisch gefärbt. Ein weiterer Blickwinkel luxemburgischer Musik befasst sich mit der Kunstmusik, und hier ist die staatliche Unabhängigkeit des Großherzogtums ein historischer Ausgangspunkt. Musiksoziologische Überlegungen leiten den Blick auf das Wesen und Werden von Musikgesellschaften („community music“). Ausgangspunkt ist eine liberalere Verfassung, durch welche den Bürgern zum ersten Mal das Versammlungsrecht angeboten wurde. Die Professionalisierung der Musik in Luxemburg nimmt ihren Ausgangspunkt mit der Entwicklung der musikalischen Bildung, welche in den Händen der ersten Komponistengeneration lag und auf die später aufgebaut werden konnte. [less ▲]

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