Last 7 days
Bookmark and Share    
Full Text
Peer Reviewed
See detailThe impact of resilience on perceived chronic stress in undergraduate psychology students
Lenz, Hannah; Steffgen, Georges UL

Poster (2019, September 26)

The purpose of this exploratory study was to analyze the relationship between academic stressors and chronic stress in undergraduate psychology students, and to identify whether resilience and/or social ... [more ▼]

The purpose of this exploratory study was to analyze the relationship between academic stressors and chronic stress in undergraduate psychology students, and to identify whether resilience and/or social support function as mediators amid this relationship. Students from the University of Luxembourg and the University of Trier (N = 152) were recruited to fill out an online questionnaire consisting of the Trier inventory of chronic stress (Schulz et al., 2004), the resilience scale (Leppert et al., 2008), the perceived social support scale (Kliem et al., 2015), and five dimensions of academic stressors (Herbst et al., 2016). Results show a positive correlation between academic stressors and chronic stress. Multiple regression analysis prove that neither gender, home university, additional occupation nor social support are significant predictors of chronic stress. Compared to academic stressors and resilience, which account for more than 56% of the variance of students’ experienced chronic stress. Furthermore, academic stressors and chronic stress are mediated by resilience but not by perceived social support. The implications of the findings are discussed in terms of their relevance for the development of intervention programs against chronic stress of undergraduate students. [less ▲]

Detailed reference viewed: 30 (1 UL)
Full Text
Peer Reviewed
See detailTHE MARKET SKEWNESS-RETURN RELATIONSHIP, Plenary Talk
Lehnert, Thorsten UL

Scientific Conference (2019, September 25)

Detailed reference viewed: 24 (1 UL)
Full Text
Peer Reviewed
See detailA material and component bank to facilitate material recycling and component reuse for a sustainable construction: concept and preliminary study
Cai, Gaochuang; Waldmann, Danièle UL

in Clean Technologies and Environmental Policy (2019)

This paper concerns the reusable components and recycled materials from demounted structures 16 which may draw a large amount of waste in construction industry. By a series of literature review 17 and ... [more ▼]

This paper concerns the reusable components and recycled materials from demounted structures 16 which may draw a large amount of waste in construction industry. By a series of literature review 17 and analyses, a material and component bank was proposed to manage more effectively the 18 recycling of materials and direct reuse of components even of whole components obtained from 19 old structures to facilitate a more sustainable construction industry. The concept, main businesses 20 and work operation of the bank were illustrated in detail including its potential management 21 method and supply chain. The relationship between the bank and current building information 22 modelling, design for deconstruction, supply chain and life cycle assessment based on the bank 23 were then analysed in detail. It can be concluded that the bank could pave the way for effectively 24 performing a further and repaid reuse of components and perfecting current recycling of materials 25 to contribute a more sustainable built environment from the view of various terms mentioned in 26 this study. The bank also can link with current method of life cycle assessment or environmental 27 impact assessment well, which all can promote the construction sustainability indicating the bank 28 can be integrated into current construction industry easily for the future. [less ▲]

Detailed reference viewed: 38 (2 UL)
Full Text
Peer Reviewed
See detailSupraferromagnetic correlations in clusters of magnetic nanoflowers
Bender, Philipp Florian UL; Honecker, Dirk UL; Fernández Barquín, Luis

in Applied Physics Letters (2019), 115

Magnetic nanoflowers are densely packed aggregates of superferromagnetically coupled iron oxide nanocrystallites, which excel during magnetic hyperthermia experiments. Here, we investigate the nature of ... [more ▼]

Magnetic nanoflowers are densely packed aggregates of superferromagnetically coupled iron oxide nanocrystallites, which excel during magnetic hyperthermia experiments. Here, we investigate the nature of the moment coupling within a powder of such nanoflowers using spin-resolved small-angle neutron scattering. Within the powder, the nanoparticles are agglomerated to clusters, and we can show that the moments of neighboring nanoflowers tend to align parallel to each other. Thus, the whole system resembles a hierarchical magnetic nanostructure consisting of three distinct levels, i.e., (i) the ferrimagnetic nanocrystallites as building blocks, (ii) the superferromagnetic nanoflowers, and (iii) the supraferromagnetic clusters of nanoflowers. We surmise that such a supraferromagnetic coupling explains the enhanced magnetic hyperthermia performance in the case of interacting nanoflowers. [less ▲]

Detailed reference viewed: 28 (0 UL)
Full Text
See detailEvaluation von bauphysikalischen Vormessungen im Rahmen von komplexen Innendämmprojekten
Latz, Sebastian Joachim UL; Thewes, Andreas; Scholzen, Frank UL et al

in Vogel, Albert (Ed.) Bauphysiktage 2019 in Weimar - Bauphysik in Forschung und Praxis (2019, September 25)

The installation of internal insulation systems within the scope of refurbishment changes the hygrothermal behaviour of the existing masonry of a building in the long term. The internal insulation layer ... [more ▼]

The installation of internal insulation systems within the scope of refurbishment changes the hygrothermal behaviour of the existing masonry of a building in the long term. The internal insulation layer reduces the temperature of the masonry during the heating period and considerably reduces the drying potential. If the moisture content is too high due to the absorption of driving rain from the outside and moisture from the interior climate, the masonry may be permanently damaged and mould may form. The proof of function can be achieved by hygrothermal simulations. These simulations require the input of sensitive boundary conditions and different material parameters. In order to obtain precise simulation results, these input values should be validated by building physics measurements. In order to be able to better assess the simulation parameters, various physical measurements for the preparation of a field test for interior insulation systems in a conference room were carried out on behalf of the administration of the bâtiments publics at the University of Luxembourg as part of the research project "Possibilities and limitations of interior insulation in the renovation of public buildings in Luxembourg". [less ▲]

Detailed reference viewed: 30 (4 UL)
Full Text
Peer Reviewed
See detailEarly-stage topological and technological choices for TSN-based communication architectures
Navet, Nicolas UL; Villanueva, Josetxo; Migge, Jörn

Scientific Conference (2019, September 24)

A main issue in the design of automotive communication architectures is that the most important design choices pertaining to the topology of the networks and the technologies to use (protocols, data rate ... [more ▼]

A main issue in the design of automotive communication architectures is that the most important design choices pertaining to the topology of the networks and the technologies to use (protocols, data rate, hardware) have to be made at a time when the communication requirements are not entirely known. Indeed, many functions only becomes available along the development cycle, and vehicle platforms have to support incremental evolutions of the embedded system that may not be fully foreseeable at the time design choices are made. The problem is becoming even more difficult and crucial with the introduction of dynamically evolving communication requirements requiring network re-configuration at run-time. We present how the use of synthetic data, that is data generated programmatically based on past vehicle projects and what can be foreseen for the current project, enables the designers to make such early stage choices based on quantified metrics. The proposals are applied to Groupe Renault's FACE service-oriented E/E architecture with the use of a software-implemented function we called “Topology Stress Test”. [less ▲]

Detailed reference viewed: 39 (1 UL)
Full Text
See detailReducibility of n-ary semigroups: from quasitriviality towards idempotency
Couceiro, Miguel; Devillet, Jimmy UL; Marichal, Jean-Luc UL et al

E-print/Working paper (2019)

Let $X$ be a nonempty set. Denote by $\mathcal{F}^n_k$ the class of associative operations $F\colon X^n\to X$ satisfying the condition $F(x_1,\ldots,x_n)\in\{x_1,\ldots,x_n\}$ whenever at least $k$ of the ... [more ▼]

Let $X$ be a nonempty set. Denote by $\mathcal{F}^n_k$ the class of associative operations $F\colon X^n\to X$ satisfying the condition $F(x_1,\ldots,x_n)\in\{x_1,\ldots,x_n\}$ whenever at least $k$ of the elements $x_1,\ldots,x_n$ are equal to each other. The elements of $\mathcal{F}^n_1$ are said to be quasitrivial and those of $\mathcal{F}^n_n$ are said to be idempotent. We show that $\mathcal{F}^n_1=\cdots =\mathcal{F}^n_{n-2}\varsubsetneq\mathcal{F}^n_{n-1}\varsubsetneq\mathcal{F}^n_n$. The class $\mathcal{F}^n_1$ was recently characterized by Couceiro and Devillet \cite{CouDev}, who showed that its elements are reducible to binary associative operations. However, some elements of $\mathcal{F}^n_n$ are not reducible. In this paper, we characterize the class $\mathcal{F}^n_{n-1}\setminus\mathcal{F}^n_1$ and show that its elements are reducible. In particular, we show that each of these elements is an extension of an $n$-ary Abelian group operation whose exponent divides $n-1$. [less ▲]

Detailed reference viewed: 44 (4 UL)
Full Text
Peer Reviewed
See detailProceedings of the Deduktionstreffen 2019
Schon, Claudia; Steen, Alexander UL

Scientific Conference (2019, September 23)

The annual meeting Deduktionstreffen is the prime activity of the Special Interest Group on Deduction Systems (FG DedSys) of the AI Section of the German Society for Informatics (GI-FBKI). It is a meeting ... [more ▼]

The annual meeting Deduktionstreffen is the prime activity of the Special Interest Group on Deduction Systems (FG DedSys) of the AI Section of the German Society for Informatics (GI-FBKI). It is a meeting with a familiar, friendly atmosphere, where everyone interested in deduction can report on their work in an informal setting. [less ▲]

Detailed reference viewed: 33 (1 UL)
Full Text
Peer Reviewed
See detailBODYFITR: Robust Automatic 3D Human Body Fitting
Saint, Alexandre Fabian A UL; Shabayek, Abd El Rahman UL; Cherenkova, Kseniya UL et al

in Proceedings of the 2019 IEEE International Conference on Image Processing (ICIP) (2019, September 22)

This paper proposes BODYFITR, a fully automatic method to fit a human body model to static 3D scans with complex poses. Automatic and reliable 3D human body fitting is necessary for many applications ... [more ▼]

This paper proposes BODYFITR, a fully automatic method to fit a human body model to static 3D scans with complex poses. Automatic and reliable 3D human body fitting is necessary for many applications related to healthcare, digital ergonomics, avatar creation and security, especially in industrial contexts for large-scale product design. Existing works either make prior assumptions on the pose, require manual annotation of the data or have difficulty handling complex poses. This work addresses these limitations by providing a novel automatic fitting pipeline with carefully integrated building blocks designed for a systematic and robust approach. It is validated on the 3DBodyTex dataset, with hundreds of high-quality 3D body scans, and shown to outperform prior works in static body pose and shape estimation, qualitatively and quantitatively. The method is also applied to the creation of realistic 3D avatars from the high-quality texture scans of 3DBodyTex, further demonstrating its capabilities. [less ▲]

Detailed reference viewed: 44 (5 UL)
Peer Reviewed
See detail(Im)mobilizing languages
Kalocsanyiova, Erika UL

Scientific Conference (2019, September 19)

This presentation is concerned with the impact of multilingualism on forced migrants’ trajectories. It reports the findings of a two-year qualitative research project, which used ethnographic research ... [more ▼]

This presentation is concerned with the impact of multilingualism on forced migrants’ trajectories. It reports the findings of a two-year qualitative research project, which used ethnographic research methods, including narrative and go-along interviews, classroom and participant observations and linguistic analysis of interactional data. The project set out to investigate how forced migrants reflect, position, and affirm themselves – through languages – in multilingual societies. Our contribution aligns itself with the body of research that challenges hegemonic monolingual and monocultural practices (Grzymala-Kazlowska/Phillimore 2018, Van Avermaet 2009). Other major influences were Juffermans and Tavares’s (2017) research on south-north trajectories and linguistic repertoires, Stevenson’s (2014, 2017) work on language (hi)stories and Busch’s (2017) biographical explorations of Spracherleben. In this talk, the focus will be on the experiences of three men from Syria and Iraq who have obtained humanitarian protection in Luxembourg, but aspire to fulfil their integration aspirations across multiple locations and countries. A careful analysis of divergent trajectories sheds light on how experiences of linguistic inequality and/or success are imprinted on forced migrants’ repertoires and shape their understanding of (successful) integration. [less ▲]

Detailed reference viewed: 27 (0 UL)
See detailWann kam die Grenze auf die Karte? Zur Konstruktion von Herrschaftsgebieten zwischen Reich und Frankreich in der Frühen Neuzeit
Uhrmacher, Martin UL

Scientific Conference (2019, September 19)

Feste politische Grenzen, wie man sie heute kennt, die ein Staatsgebiet nach innen wie nach außen umfassend begrenzen, sind im Raum zwischen Maas und Rhein ein Produkt des späten 18. Jahrhunderts. Für ... [more ▼]

Feste politische Grenzen, wie man sie heute kennt, die ein Staatsgebiet nach innen wie nach außen umfassend begrenzen, sind im Raum zwischen Maas und Rhein ein Produkt des späten 18. Jahrhunderts. Für diese Region wird nach dem Ursprung dieser festen Grenzlinien gesucht, die heute ein selbstverständlicher Bestandteil von Karten sind. Seit dem späten 16. Jahrhundert wurden im Westen des Heiligen Römischen Reiches erstmals historische Karten publiziert und im Druck verbreitet, die unser Bild der territorialen Landschaft bis heute prägen. Ab wann aber werden solche Grenzlinien zur Darstellung territorial-räumlicher Verhältnisse verwendet? Und welche Rolle kommt ihnen bei der Konstruktion von Herrschaft im Raum zu? Diesen Fragen widmet sich der Beitrag für die Region zwischen Maas und Rhein. Sie liegt an der Schnittstelle von Germania und Romania und ist durch Einflüsse beiderseits der Sprachgrenze geprägt. [less ▲]

Detailed reference viewed: 24 (0 UL)
See detailSize-dependent spatial magnetization profile of Manganese-Zinc ferrite nanoparticles
Bersweiler, Mathias UL

Scientific Conference (2019, September 18)

Detailed reference viewed: 26 (0 UL)
Peer Reviewed
See detailMale vs female gamers: Testing the stereotype threat effect in video gaming
Holl, Elisabeth UL; Wagener, Gary Lee; Melzer, André UL

Scientific Conference (2019, September 17)

Stereotype threat (ST), defined as the risk of confirming a negative stereotype about one’s own group, has been demonstrated in various social contexts. Regarding video games, for example, informing ... [more ▼]

Stereotype threat (ST), defined as the risk of confirming a negative stereotype about one’s own group, has been demonstrated in various social contexts. Regarding video games, for example, informing female participants that men would outperform women in gaming leads to gender differences in performance. To date, however, these studies have not looked into the mechanisms of this ST effect in gaming. In two lab studies (N=186), some participants were confronted with ST-related information before playing a video game. In Study 1, half of the participants read a bogus article confirming the “standard” gender stereotype (“men outperform women”). In Study 2, a reverse stereotype was presented to half of the participants (“women have outpaced men in some game genres”). In contrast to hypotheses, both studies failed to show the expected significant interaction effect of gender and ST condition on performance, although female participants confronted with the “standard” gender stereotype reported greater frustration in Study 1, for example. In sum, results indicate a complex relationship between gender, social identity, experience with the game genre, and behavior. Identifying oneself as a gamer and being experienced in a particular game genre were found to be better performance predictors than reading stereotype threatening information. [less ▲]

Detailed reference viewed: 34 (1 UL)
Full Text
Peer Reviewed
See detailImpact of reinforcement to moment resistance of composite slabs
Zhang, Qingjie UL; Schäfer, Markus UL; Kurz, Wolfgang

in The 2019 World Congress on Advances in Structural Engineering and Mechanics (ASEM19) (2019, September 17)

Composite slabs lead to slim and economic structural solutions with a low selfweight. The determination of their moment resistance follows the regulations presented in EN 1994-1-1 (2004) which are based ... [more ▼]

Composite slabs lead to slim and economic structural solutions with a low selfweight. The determination of their moment resistance follows the regulations presented in EN 1994-1-1 (2004) which are based on plastic design methods. The current version of Eurocode 4 does not consider explicitly additional reinforcement in the ribs for sagging moment resistance. However, the construction industry requires this possibility in order to provide economical and flexible design. Regarding this situation, further investigations are necessary to prove the applicability of plastic design methods. In the case of high bottom reinforcement ratio, a deep position of the plastic neutral axis occurs, and concrete compression failure may happen before most parts of the profiled steel sheeting and reinforcement yield. This leads to an overestimation of the bending resistance according to the plastic design method. A parametric study, based on approximately 290.000 different combinations of various cross-section geometries and materials, is provided to compare the plastic moment resistance with the resistance determined by strain-limited design. The results show that limitations are necessary to be enabled for the general application of plastic design methods. [less ▲]

Detailed reference viewed: 24 (0 UL)
Full Text
See detailUpdate Internationales und Europäisches IT-Steuerrecht
Sinnig, Julia UL

Presentation (2019, September 14)

Detailed reference viewed: 32 (0 UL)
Full Text
See detailLaurent Menager (1835-1902), der musikalische Botschafter Luxemburgs im 19. Jahrhundert
Sagrillo, Damien UL

Conference given outside the academic context (2019)

Detailed reference viewed: 28 (1 UL)
Full Text
See detailAssessment and Improvement of the Practical Use of Mutation for Automated Software Testing
Titcheu Chekam, Thierry UL

Doctoral thesis (2019)

Software testing is the main quality assurance technique used in software engineering. In fact, companies that develop software and open-source communities alike actively integrate testing into their ... [more ▼]

Software testing is the main quality assurance technique used in software engineering. In fact, companies that develop software and open-source communities alike actively integrate testing into their software development life cycle. In order to guide and give objectives for the software testing process, researchers have designed test adequacy criteria (TAC) which, define the properties of a software that must be covered in order to constitute a thorough test suite. Many TACs have been designed in the literature, among which, the widely used statement and branch TAC, as well as the fault-based TAC named mutation. It has been shown in the literature that mutation is effective at revealing fault in software, nevertheless, mutation adoption in practice is still lagging due to its cost. Ideally, TACs that are most likely to lead to higher fault revelation are desired for testing and, the fault-revelation of test suites is expected to increase as their coverage of TACs test objectives increase. However, the question of which TAC best guides software testing towards fault revelation remains controversial and open, and, the relationship between TACs test objectives’ coverage and fault-revelation remains unknown. In order to increase knowledge and provide answers about these issues, we conducted, in this dissertation, an empirical study that evaluates the relationship between test objectives’ coverage and fault-revelation for four TACs (statement, branch coverage and, weak and strong mutation). The study showed that fault-revelation increase with coverage only beyond some coverage threshold and, strong mutation TAC has highest fault revelation. Despite the benefit of higher fault-revelation that strong mutation TAC provide for software testing, software practitioners are still reluctant to integrate strong mutation into their software testing activities. This happens mainly because of the high cost of mutation analysis, which is related to the large number of mutants and the limitation in the automation of test generation for strong mutation. Several approaches have been proposed, in the literature, to tackle the analysis’ cost issue of strong mutation. Mutant selection (reduction) approaches aim to reduce the number of mutants used for testing by selecting a small subset of mutation operator to apply during mutants generation, thus, reducing the number of analyzed mutants. Nevertheless, those approaches are not more effective, w.r.t. fault-revelation, than random mutant sampling (which leads to a high loss in fault revelation). Moreover, there is not much work in the literature that regards cost-effective automated test generation for strong mutation. This dissertation proposes two techniques, FaRM and SEMu, to reduce the cost of mutation testing. FaRM statically selects and prioritizes mutants that lead to faults (fault-revealing mutants), in order to reduce the number of mutants (fault-revealing mutants represent a very small proportion of the generated mutants). SEMu automatically generates tests that strongly kill mutants and thus, increase the mutation score and improve the test suites. First, this dissertation makes an empirical study that evaluates the fault-revelation (ability to lead to tests that have high fault-revelation) of four TACs, namely statement, branch, weak mutation and strong mutation. The outcome of the study show evidence that for all four studied TACs, the fault-revelation increases with TAC test objectives’ coverage only beyond a certain threshold of coverage. This suggests the need to attain higher coverage during testing. Moreover, the study shows that strong mutation is the only studied TAC that leads to tests that have, significantly, the highest fault-revelation. Second, in line with mutant reduction, we study the different mutant quality indicators (used to qualify "useful" mutants) proposed in the literature, including fault-revealing mutants. Our study shows that there is a large disagreement between the indicators suggesting that the fault-revealing mutant set is unique and differs from other mutant sets. Thus, given that testing aims to reveal faults, one should directly target fault-revealing mutants for mutant reduction. We also do so in this dissertation. Third, this dissertation proposes FaRM, a mutant reduction technique based on supervised machine learning. In order to automatically discriminate, before test execution, between useful (valuable) and useless mutants, FaRM build a mutants classification machine learning model. The features for the classification model are static program features of mutants categorized as mutant types and mutant context (abstract syntax tree, control flow graph and data/control dependency information). FaRM’s classification model successfully predicted fault-revealing mutants and killable mutants. Then, in order to reduce the number of analyzed mutants, FaRM selects and prioritizes fault-revealing mutants based of the aforementioned mutants classification model. An empirical evaluation shows that FaRM outperforms (w.r.t. the accuracy of fault-revealing mutant selection) random mutants sampling and existing mutation operators-based mutant selection techniques. Fourth, this dissertation proposes SEMu, an automated test input generation technique aiming to increase strong mutation coverage score of test suites. SEMu is based on symbolic execution and leverages multiple cost reduction heuristics for the symbolic execution. An empirical evaluation shows that, for limited time budget, the SEMu generates tests that successfully increase strong mutation coverage score and, kill more mutants than test generated by state-of-the-art techniques. Finally, this dissertation proposes Muteria a framework that enables the integration of FaRM and SEMu into the automated software testing process. Overall, this dissertation provides insights on how to effectively use TACs to test software, shows that strong mutation is the most effective TAC for software testing. It also provides techniques that effectively facilitate the practical use of strong mutation and, an extensive tooling to support the proposed techniques while enabling their extensions for the practical adoption of strong mutation in software testing. [less ▲]

Detailed reference viewed: 64 (12 UL)
See detailSocial stratification in higher education trajectories: A sequence-analytical approach
Haas, Christina UL

Scientific Conference (2019, September 13)

Detailed reference viewed: 34 (1 UL)
See detailL'imaginaire de la logique contractuelle : subversion, reconnaissance, résonance - autour de l'arrêt Churchill Falls
Bélanger, André; Saint-Onge, Simon; Dufour, Pascale UL et al

Presentation (2019, September 13)

Les trois conférencier(ière)s, avec la collaboration de Jean-Guy Belley, se proposent d’investir le contrat, instrument juridique qui se donne à penser comme un pharmakon, c’est-à-dire comme un bouc ... [more ▼]

Les trois conférencier(ière)s, avec la collaboration de Jean-Guy Belley, se proposent d’investir le contrat, instrument juridique qui se donne à penser comme un pharmakon, c’est-à-dire comme un bouc-émissaire à qui l’on impute un tort social en contexte néo-libéral. Envisager le contrat comme un pharmakon, c’est, certes, percevoir en lui l’expression d’un oubli de la relation de droit comme relation sociale, mais aussi le potentiel d’une solution à ce même problème. À partir de l’arrêt de la Cour suprême Churchill Falls et à travers le spectre de la Théorie critique (la subversion chez Theodor W. Adorno, la reconnaissance chez Axel Honneth et la résonance chez Hartmut Rosa), l’imaginaire du contrat déploie ces deux facettes que sont celles d’être le poison et le remède au déficit relationnel du lien juridique. [less ▲]

Detailed reference viewed: 25 (0 UL)