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See detailDie Vorhersage von Selbstkontrolle durch Need for Cognition. Generalisierbarkeit und Erklärungsansätze
Grass, Julia; Krieger, Florian UL; Paulus, P. et al

Scientific Conference (2018, September)

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See detailHybrid MPI+OpenMP Implementation of eXtended Discrete Element Method
Mainassara Chekaraou, Abdoul Wahid UL; Rousset, Alban UL; Besseron, Xavier UL et al

in Proc. of the 9th Workshop on Applications for Multi-Core Architectures (WAMCA'18), part of 30th Intl. Symp. on Computer Architecture and High Performance Computing (SBAC-PAD 2018) (2018, September)

The Extended Discrete Element Method (XDEM) is a novel and innovative numerical simulation technique that ex- tends classical Discrete Element Method (DEM) (which simulates the motion of granular material ... [more ▼]

The Extended Discrete Element Method (XDEM) is a novel and innovative numerical simulation technique that ex- tends classical Discrete Element Method (DEM) (which simulates the motion of granular material), by additional properties such as the chemical composition, thermodynamic state, stress/strain for each particle. It has been applied successfully to numerous industries involving the processing of granular materials such as sand, rock, wood or coke [16], [17]. In this context, computational simulation with (X)DEM has become a more and more essential tool for researchers and scientific engineers to set up and explore their experimental processes. However, increasing the size or the accuracy of a model requires the use of High Performance Computing (HPC) platforms over a parallelized implementation to accommodate the growing needs in terms of memory and computation time. In practice, such a parallelization is traditionally obtained using either MPI (distributed memory computing), OpenMP (shared memory computing) or hybrid approaches combining both of them. In this paper, we present the results of our effort to implement an OpenMP version of XDEM allowing hybrid MPI+OpenMP simulations (XDEM being already parallelized with MPI). Far from the basic OpenMP paradigm and recommendations (which simply summarizes by decorating the main computation loops with a set of OpenMP pragma), the OpenMP parallelization of XDEM required a fundamental code re-factoring and careful tuning in order to reach good performance. There are two main reasons for those difficulties. Firstly, XDEM is a legacy code devel- oped for more than 10 years, initially focused on accuracy rather than performance. Secondly, the particles in a DEM simulation are highly dynamic: they can be added, deleted and interaction relations can change at any timestep of the simulation. Thus this article details the multiple layers of optimization applied, such as a deep data structure profiling and reorganization, the usage of fast multithreaded memory allocators and of advanced process/thread-to-core pinning techniques. Experimental results evaluate the benefit of each optimization individually and validate the implementation using a real-world application executed on the HPC platform of the University of Luxembourg. Finally, we present our Hybrid MPI+OpenMP results with a 15%-20% performance gain and how it overcomes scalability limits (by increasing the number of compute cores without dropping of performances) of XDEM-based pure MPI simulations. [less ▲]

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See detailLes blockchains en 50 questions: comprendre le fonctionnement et les enjeux de cette technologie innovante
Dumas, J.-G.; Lafourcade, P.; Tichit, A. et al

Book published by Dunod - 1er (2018)

Depuis l’avènement du bitcoin, les innovations liées à la blockchain sont en plein essor. Cet ouvrage tente d’expliquer le fonctionnement de cette technologie innovante mais aussi ses applications au ... [more ▼]

Depuis l’avènement du bitcoin, les innovations liées à la blockchain sont en plein essor. Cet ouvrage tente d’expliquer le fonctionnement de cette technologie innovante mais aussi ses applications au travers de 50 questions comme: - Qu’est-ce qu’une blockchain ? - Quel est le lien entre bitcoin et blockchains ? - Qui sont les mineurs et que font-ils ? - Qu’est ce qu’un consensus ? - Quelle est la part des cryptomonnaies dans l’économie mondiale ? - Qu’est-ce qu’un contrat intelligent ? - Peut-on faire une blockchain sans bloc ? - Comment les blockchains vont changer le monde de demain ? Les réponses à toutes ces questions et à 42 autres sont dans ce livre. [less ▲]

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See detailRare coding variants in genes encoding GABAA receptors in genetic generalised epilepsies: an exome-based case-control study
May, Patrick UL; Girard, Simon; Harrer, Merle et al

in Lancet Neurology (2018), 17(8), 699-708

Background Genetic generalised epilepsy is the most common type of inherited epilepsy. Despite a high concordance rate of 80% in monozygotic twins, the genetic background is still poorly understood. We ... [more ▼]

Background Genetic generalised epilepsy is the most common type of inherited epilepsy. Despite a high concordance rate of 80% in monozygotic twins, the genetic background is still poorly understood. We aimed to investigate the burden of rare genetic variants in genetic generalised epilepsy. Methods For this exome-based case-control study, we used three different genetic generalised epilepsy case cohorts and three independent control cohorts, all of European descent. Cases included in the study were clinically evaluated for genetic generalised epilepsy. Whole-exome sequencing was done for the discovery case cohort, a validation case cohort, and two independent control cohorts. The replication case cohort underwent targeted next-generation sequencing of the 19 known genes encoding subunits of GABAA receptors and was compared to the respective GABAA receptor variants of a third independent control cohort. Functional investigations were done with automated two-microelectrode voltage clamping in Xenopus laevis oocytes. Findings Statistical comparison of 152 familial index cases with genetic generalised epilepsy in the discovery cohort to 549 ethnically matched controls suggested an enrichment of rare missense (Nonsyn) variants in the ensemble of 19 genes encoding GABAA receptors in cases (odds ratio [OR] 2·40 [95% CI 1·41–4·10]; pNonsyn=0·0014, adjusted pNonsyn=0·019). Enrichment for these genes was validated in a whole-exome sequencing cohort of 357 sporadic and familial genetic generalised epilepsy cases and 1485 independent controls (OR 1·46 [95% CI 1·05–2·03]; pNonsyn=0·0081, adjusted pNonsyn=0·016). Comparison of genes encoding GABAA receptors in the independent replication cohort of 583 familial and sporadic genetic generalised epilepsy index cases, based on candidate-gene panel sequencing, with a third independent control cohort of 635 controls confirmed the overall enrichment of rare missense variants for 15 GABAA receptor genes in cases compared with controls (OR 1·46 [95% CI 1·02–2·08]; pNonsyn=0·013, adjusted pNonsyn=0·027). Functional studies for two selected genes (GABRB2 and GABRA5) showed significant loss-of-function effects with reduced current amplitudes in four of seven tested variants compared with wild-type receptors. Interpretation Functionally relevant variants in genes encoding GABAA receptor subunits constitute a significant risk factor for genetic generalised epilepsy. Examination of the role of specific gene groups and pathways can disentangle the complex genetic architecture of genetic generalised epilepsy. [less ▲]

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See detailThe Association Between Cyberbullying, School Bullying, and Suicidality Among Adolescents
Zaborskis, Apolinaras; Ilionsky, Gabriela; Tesler, Riki et al

in Crisis (2018)

Background: Bullying and suicidality are serious worldwide problems with negative effects on the young population and therefore international comparisons in this field are of paramount importance. Aims ... [more ▼]

Background: Bullying and suicidality are serious worldwide problems with negative effects on the young population and therefore international comparisons in this field are of paramount importance. Aims: To analyze the prevalence of bullying and cyberbullying and their association with suicidal behavior among school-aged children in Israel, Lithuania, and Luxembourg. Method: In total, 3,814 15-year-olds from schools in Israel, Lithuania, and Luxembourg were surveyed in the Health Behavior in School-Aged Children (HBSC) cross-national survey in 2013/2014 using standardized anonymous questionnaires. Data analysis employed logistic regression and structural equation modeling (SEM). Results: In all, 6.5% of the adolescents reported being cyberbullied, 15.6% reported being bullied at school. In the previous 12 months, 38.6% reported experiencing emotions that stopped them from doing their usual activities, 17.8% considered attempting suicide, 12.0% made a suicide plan, and 9.5% attempted suicide. Victims of cyberbullying and school bullying had a significantly higher risk of suicidal ideations, plans, and attempts. The SEM analysis confirmed a significant overall effect of bullying on adolescent suicidality. The strongest effect was seen among Israeli students. Limitations: The prevalence estimates were obtained by self-report. Conclusion: The prevalence of adolescent cyberbullying, school bullying, and suicidal behavior is relatively high in Israel, Lithuania, and Luxembourg. Cyberbullying is a strong predictor of adolescent suicidality. [less ▲]

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See detailResource Allocation and Relay Selection for Multi-User OFDM-Based Cooperative Networks with SWIPT
Gautam, Sumit UL; Lagunas, Eva UL; Chatzinotas, Symeon UL et al

Scientific Conference (2018, August)

In this paper, we investigate resource allocation and relay selection in a two-hop relay-assisted multi-user network, where the end users support Simultaneous Wireless Information and Power Transfer ... [more ▼]

In this paper, we investigate resource allocation and relay selection in a two-hop relay-assisted multi-user network, where the end users support Simultaneous Wireless Information and Power Transfer (SWIPT). In particular, we consider single source assisted by a set of spatially distributed relays able to amplify-and-forward orthogonal frequency division multiplexing (OFDM) signals carrying both data and power at the same time. The users are assumed to implement a power splitting technique where the received signal is orthogonally split in two streams of different power levels, where one signal stream is sent to the power harvesting module while the other is converted to baseband for information decoding. We aim at optimizing the users’ power splitting ratios as well as the relay, carrier and power assignment so that the end-users’ sum-rate is maximized subject to transmitted and harvested power constraints. Such joint optimization is combinatorial in nature with a non-convex structure. Therefore, we present a sub-optimal low complex solution based on the harmonic mean of the two-hop relay channel coefficients. Simulation results reveal that the proposed algorithm provides significant performance gains in comparison with a semi-random resource allocation and relay selection approach. [less ▲]

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See detailAutomated Extraction of Semantic Legal Metadata Using Natural Language Processing
Sleimi, Amin UL; Sannier, Nicolas UL; Sabetzadeh, Mehrdad UL et al

in the 26th IEEE International Requirements Engineering Conference, Banff, Alberta, 20-24 August 2018 (2018, August)

[Context] Semantic legal metadata provides information that helps with understanding and interpreting the meaning of legal provisions. Such metadata is important for the systematic analysis of legal ... [more ▼]

[Context] Semantic legal metadata provides information that helps with understanding and interpreting the meaning of legal provisions. Such metadata is important for the systematic analysis of legal requirements. [Objectives] Our work is motivated by two observations: (1) The existing requirements engineering (RE) literature does not provide a harmonized view on the semantic metadata types that are useful for legal requirements analysis. (2) Automated support for the extraction of semantic legal metadata is scarce, and further does not exploit the full potential of natural language processing (NLP). Our objective is to take steps toward addressing these limitations. [Methods] We review and reconcile the semantic legal metadata types proposed in RE. Subsequently, we conduct a qualitative study aimed at investigating how the identified metadata types can be extracted automatically. [Results and Conclusions] We propose (1) a harmonized conceptual model for the semantic metadata types pertinent to legal requirements analysis, and (2) automated extraction rules for these metadata types based on NLP. We evaluate the extraction rules through a case study. Our results indicate that the rules generate metadata annotations with high accuracy. [less ▲]

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See detailTapping the Potential of Diverse Founding Teams for Firm Growth: The Role of New Venture Activities
Tryba, Anne UL; Patzelt, Holger; Breugst, Nicola

Scientific Conference (2018, August)

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See detailMetamorphosis of educational understanding: Temporary Integration regarding Syrians in Turkey
Samuk, Sahizer UL

in Border Crossing (2018)

The integration of refugees in Turkey has been realized in the field with the help of DGMM (Directorate General on Migration Management), Kızılay and UNHCR mainly, and by many more international and non ... [more ▼]

The integration of refugees in Turkey has been realized in the field with the help of DGMM (Directorate General on Migration Management), Kızılay and UNHCR mainly, and by many more international and non-governmental organizations that have supported refugees by answering their short-term needs such as giving them cards for shopping, clothes, preparing them for winter (“winterization”) and providing educational assistance. I conducted 15 interviews with state officials, various NGOs and a few refugees. During my research many interesting points about integration policies (to-be-formed) at the moment in Turkey were discovered. One interesting finding was that the state officials do not like to use the word “integration”, as it is reminiscent of the way Turkish migrant workers were treated in Germany, where assimilation and integration were understood as the same concept. I use the term “temporary integration” for the case of all refugees, but this paper will focus mostly on the Syrians’ case. Within the context of temporariness, this paper’s central attention will be the educational integration of Syrian refugees in Turkey. I argue in the paper that the temporariness and the nostalgia with the Ottoman past are two main elements mostly present regarding the educational integration of Syrians in Turkey. [less ▲]

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See detailSpectroscopic Studies of dissimilar Al-Cu laser welding
Schmalen, Pascal Guy UL; Plapper, Peter UL

in proceedings of asme msec 2018 (2018)

This paper describes a novel method to analyze the effect of the fiber laser induced plasma on welding of dissimilar Al and Cu. Based on spectroscopic studies, specific wavelengths were found to be ... [more ▼]

This paper describes a novel method to analyze the effect of the fiber laser induced plasma on welding of dissimilar Al and Cu. Based on spectroscopic studies, specific wavelengths were found to be suitable for process monitoring during laser welding. For aluminum, the double peak at 394.4 and 396.1 nm was studied, for cu the 578 nm peak was studied. The characteristic peaks were observed by multiple photodiodes equipped with narrow optical filters with varying FWHM. Analyzing the plasma emissions of the process enabled to detect material changes in the plasma plume. This novel method has the advantage of higher sampling rate combined with reduced costs compared to a spectrometer and is thus able to capture the process dynamics. [less ▲]

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See detailInforming a social practice theory framework with social-psychological factors for analyzing routinized energy consumption: A multivariate analysis of three practices
Hess, Ann-Kathrin; Samuel, Robin UL; Burger, Paul

in Energy Research & Social Science (2018), 46

A key factor contributing to the non-realization of energy efficiency potentials is the routinized way in which many energy consumption behaviors (ECBs) are performed. To analyze routinized ECBs, we draw ... [more ▼]

A key factor contributing to the non-realization of energy efficiency potentials is the routinized way in which many energy consumption behaviors (ECBs) are performed. To analyze routinized ECBs, we draw on social practice theory and psychological concepts and suggest a framework that considers individual, social, and material factors. Based on our proposed framework and employing multivariate regression analysis, we gain new insights into associated factors of routinized ECBs—particularly for washing and drying clothes and showering. Analyzing data from a survey conducted among Swiss households in 2016 (n=5015), we find that individual values, practice-specific wants, and materials explain variations in routinized ECB performance. Furthermore, socio-demographic predictors shed light on cultural and status differences associated with routinized ECBs. This paper contributes to understanding associated factors of routinized ECBs by bridging practice theory and psychology-based factors. [less ▲]

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See detailA risk-based approach towards infringement prevention on the internet: adopting the anti-money laundering framework to online platforms
Ullrich, Carsten UL

in International Journal of Law and Information Technology (2018)

This article suggests a new approach towards online service provider liability which relies on duty of care. It proposes a concrete compliance framework for online platforms, borrowed from risk regulation ... [more ▼]

This article suggests a new approach towards online service provider liability which relies on duty of care. It proposes a concrete compliance framework for online platforms, borrowed from risk regulation, and modelled on anti-money laundering (AML) obligations in the financial sector. First, the prohibition on obliging platforms to monitor content in a general manner under the E-Commerce Directive will be discussed. On the face of it this may clash with a standardized requirement to filter for infringing content. Subsequently, the regulatory choice for such a duty of care standard will be explored. It is argued that the largely self-regulatory proposals currently on the table may be ill fitted to achieve traction and accountability. Finally, a three-tier compliance framework, modelled on the AML system and using a risk-based approach, is proposed. The pitfalls of such a highly automated compliance solution, which enforces complex legal norms, will also be touched on. [less ▲]

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See detailFlows and mobilities in the Greater Region
Pigeron-Piroth, Isabelle UL

Conference given outside the academic context (2018)

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See detailThe Challenge of Situating Sacred Wind Music on the Example of Laurent Menager (1835-1902)
Duhr, Marlène UL

Scientific Conference (2018, July 20)

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