Last 7 days
Bookmark and Share    
Full Text
Peer Reviewed
See detailEvery quasitrivial n-ary semigroup is reducible to a semigroup
Couceiro, Miguel; Devillet, Jimmy UL

in Algebra Universalis (in press)

We show that every quasitrivial n-ary semigroup is reducible to a binary semigroup, and we provide necessary and sufficient conditions for such a reduction to be unique. These results are then refined in ... [more ▼]

We show that every quasitrivial n-ary semigroup is reducible to a binary semigroup, and we provide necessary and sufficient conditions for such a reduction to be unique. These results are then refined in the case of symmetric n-ary semigroups. We also explicitly determine the sizes of these classes when the semigroups are defined on finite sets. As a byproduct of these enumerations, we obtain several new integer sequences. [less ▲]

Detailed reference viewed: 139 (21 UL)
Full Text
Peer Reviewed
See detailHigh-performance modeling of concrete ageing
Habera, Michal UL; Zilian, Andreas UL

in Proceedings in Applied Mathematics and Mechanics (in press)

Long-term behaviour of concrete structural elements is very important for evaluation of its health and serviceability range. The phenomena that must be considered are complex and lead to coupled ... [more ▼]

Long-term behaviour of concrete structural elements is very important for evaluation of its health and serviceability range. The phenomena that must be considered are complex and lead to coupled multiphysics formulations. Such formulations are difficult not only from physical perspective, but also from computational perspective. In this contribution attention to computational efficiency and effective implementation is payed. Presented model for concrete ageing is based on microprestress-solidification (MPS) theory of Bazant [1], Kunzel’s model for heat and moisture transport [2] and Mazars model for damage [3]. Ageing linear viscoelastic response, which is immanent to MPS theory and concrete creep, leads to ordinary differetial equation for internal variables solved for every quadrature/nodal point. Numerical structure of the finite element discretisation is examined. Few simplifications on physical model lead to a very efficient linear algebra problem for which standard preconditioned Krylov solvers are reviewed. In parallel, weak and strong scaling tests are performed. All results are produced within open-source finite element framework FEniCS [4]. These models are usually a basis for more involved thermo-hygro-chemo-mechanical (THCM) models with migrating chemical species. It is anticipated, that presented results will help practitioners or other structural engineerers with the choice of suitable and efficient methods for long-term concrete modeling. [less ▲]

Detailed reference viewed: 70 (7 UL)
Full Text
Peer Reviewed
See detailCan the Plight of the European Banking Structural Reforms be a Blessing in Disguise?
Nabilou, Hossein UL

in European Business Organization Law Review (in press)

One of the problems perceived to be at the heart of the global financial crisis was an amalgamation of various commercial and investment banking activities under one entity, as well as the ... [more ▼]

One of the problems perceived to be at the heart of the global financial crisis was an amalgamation of various commercial and investment banking activities under one entity, as well as the interconnectedness of the banking entities with other financial institutions, investment funds, and the shadow banking system. This paper focuses on various measures that aim to structurally separate the banking entities and their core functions from riskier financial activities such as (proprietary) trading or investments in alternative investment funds. Although banking structural reforms in the EU, UK, and the US have taken different forms, their common denominator is the separation of core banking functions from certain trading or securities market activities. Having reviewed the arguments for and against banking structural reforms and their varieties in major jurisdictions, including the EU, UK, US, France, and Germany, the paper argues that a more nuanced approach to introducing such measures at the EU level is warranted. Given the different market structures across the Atlantic and the lack of conclusive evidence on the beneficial impact of banking structural reforms, the paper concludes that the withdrawal of the banking structural reforms proposal by the European Commission has been a prudent move. It seems that in the absence of concrete evidence, experimenting with structural reforms at the Member-State level would be less costly and would provide for opportunities for learning from smaller mistakes that could pave the way for a more optimal approach to introducing banking structural reforms at the European level in the future. [less ▲]

Detailed reference viewed: 49 (3 UL)
Peer Reviewed
See detailPromoting multilingualism and multiliteracies through storytelling: a casestudy on the use of the app iTEO in preschools in Luxembourg
Kirsch, Claudine UL

in Breuer, Ester; Lindgren, Eva; Stavans, anat (Eds.) et al Multilingual Literacy (2020)

Detailed reference viewed: 44 (2 UL)
Full Text
Peer Reviewed
See detailSuicide Prevention: Using the Number of Health Complaints as an Indirect Alternative for Screening Suicidal Adolescents
Heinz, Andreas UL; Catunda, Carolina UL; van Duin, Claire UL et al

in Journal of Affective Disorders (2020), 260

Background: Suicide is the second leading cause of death in adolescents. Screening for persons at risk usually includes asking about suicidal ideation, which is considered inappropriate in some societies ... [more ▼]

Background: Suicide is the second leading cause of death in adolescents. Screening for persons at risk usually includes asking about suicidal ideation, which is considered inappropriate in some societies and situations. To avoid directly addressing suicide, this paper investigates whether the Health Behaviour in School-aged Children Symptom Checklist (HBSC-SCL), a validated non-clinical measure of eight subjective health complaints (e.g. headache, feeling low), could be used as a tool for screening suicidal ideation and behavior in adolescents. Methods: 5262 secondary school students aged 12-18 answered the Luxembourgish HBSC 2014 survey, including the HBSC-SCL items and suicidal ideation and behavior questions. Results: Each HBSC-SCL item correlates with suicidal ideation and behavior. A sum score was calculated ranging from zero to eight health complaints to predict respondents who considered suicide (area under the ROC curve = .770). The ideal cut-off for screening students who consider suicide is three or more health complaints: sensitivity is 66.3%, specificity is 75.9% and positive predictive value is 32.9%. Limitations: One limitation is HBSC-SCL's low positive predictive value. This is a general problem of screening rare events: the lower the prevalence, the lower the positive predictive value. Sensitivity and specificity could be improved by taking age-, gender- and country-specific cut-off values, but such refinements would make the score calculation more complicated. Conclusions: The HBSC-SCL is short, easy to use, with satisfactory screening properties. The checklist can be used when suicide cannot be addressed directly, and also in a more general context, e.g. by school nurses when screening adolescents. [less ▲]

Detailed reference viewed: 102 (18 UL)
Full Text
Peer Reviewed
See detailThe joint role of impulsivity and distorted cognitions in recreational and problem gambling: A cluster analytic approach.
Devos, Mr Gaetan; Clark, Luke; Bowden-Jones, Henrietta et al

in Journal of affective disorders (2020), 260

BACKGROUND AND AIMS: The Pathways Model (Blaszczynski & Nower, 2002) posits that problem gambling is a heterogeneous disorder with distinct subgroups (behaviorally conditioned gamblers, emotionally ... [more ▼]

BACKGROUND AND AIMS: The Pathways Model (Blaszczynski & Nower, 2002) posits that problem gambling is a heterogeneous disorder with distinct subgroups (behaviorally conditioned gamblers, emotionally vulnerable gamblers, and antisocial-impulsivist gamblers). Impulsivity traits and gambling-related cognitions are recognized as two key psychological factors in the onset and maintenance of problem gambling. To date, these constructs have been explored separately, and their joint role in determining problem gambling subtypes has received little attention. The goal of our study was to identify subgroups of gamblers based on impulsivity traits and gambling-related cognitions, and to determine whether this approach is consistent with the Pathways model. METHODS: Gamblers from the community (N=709) and treatment-seeking pathological gamblers (N=122) completed questionnaires measuring gambling habits, disordered gambling symptoms, gambling-related cognitions, and impulsivity traits. RESULTS: Cluster analyses revealed that three clusters globally aligned with the pathways proposed by Blaszczynski & Nower (2002). Two other clusters emerged: (1) impulsive gamblers without cognitive-related cognitions; and (2) gamblers without impulsivity or gambling-related cognitions. Gamblers with both heightened impulsive traits and gambling-related cognitions had more severe problem gambling symptoms. CONCLUSION: We successfully identified, based on an a priori theoretical framework, different subtypes of gamblers that varied in terms of problem gambling symptoms and clinical status. The diversity of the cluster profiles supports the development of personalized prevention strategies and psychological interventions. [less ▲]

Detailed reference viewed: 41 (0 UL)
See detailPlayers' moral decisions in virtual worlds: Morality in video games
Melzer, André UL; Holl, Elisabeth UL

Book published by Oxford University Press (2020)

Detailed reference viewed: 64 (4 UL)
Full Text
Peer Reviewed
See detailCVH Malach – Centrum vizuální historie Konference a workshop o novém přístupu a využití video databáze Fortunoff
Bronec, Jakub UL

in Marginalia Historica (2020)

On May 18, I took part in a very interesting workshop organized by the Malach Centre for Visual History at the Faculty of Mathematics and Physics of the Charles University in Prague. This exceptional ... [more ▼]

On May 18, I took part in a very interesting workshop organized by the Malach Centre for Visual History at the Faculty of Mathematics and Physics of the Charles University in Prague. This exceptional association provides local access to the extensive digital archives of the USC Shoah Foundation - the Institute for Visual history and Education (USC), the Refugee Voices archive of the Association of Jewish Refugees and the testimony collection of the Jewish Holocaust Centre in Melbourne. Nevertheless, the workshop focused on the newly incorporated Fortunoff Video Archive (FVA) that belongs to the category of long-awaited ingestion, and the path to get a licence was more than difficult. The archive represents a new source for all scholars including me, but in this short comment, I would like to critically point out to several minor drawbacks. [less ▲]

Detailed reference viewed: 34 (2 UL)
Full Text
Peer Reviewed
See detailExperimental and analytical analysis of the load-bearing capacity Pu of improved dry-stacked masonry
Chewe Ngapeya, Gelen Gael UL; Waldmann, Danièle UL

in Journal of Building Engineering (2020), 27

Dry-Stacked Masonry (DSM) as structural load-bearing element is still unexploited because of many factors including the early face-shell cracking, the impacts of the block imperfections on the wall load ... [more ▼]

Dry-Stacked Masonry (DSM) as structural load-bearing element is still unexploited because of many factors including the early face-shell cracking, the impacts of the block imperfections on the wall load-bearing capacity (Pu) and the lack of design code safely predicting Pu. Through experimental tests, this paper investigates a strategy for improving Pu of DSM by placing an additional horizontal contact layer on the top face of raw DSM blocks. The effect of four mixtures used to improve the raw DSM blocks has been investigated. Further, a mathematical model predicting Pu is proposed which takes into account the effects of the block imperfections. In the course of the investigation, 20 DSM wallets and 25 DSM prisms built with raw and improved DSM blocks were tested to failure under axial compression. In the former, the face-shell cracking load (Pcrack) and the load-bearing capacity (Pu) were recorded, while in the latter, the actual contact area was recorded in hundred full bed-joints using Prescale Fujifilm strips. The results showed that a contact layer of well-defined properties increased the actual contact area from 23% to 55% and improved Pu by 31,9%. The mathematical model for the raw DSM blocks predicts Pu with a mean accuracy of 93% and a standard deviation of 12% where the standards EN 1996-1-1 for mortared masonry exhibited a mean accuracy of 137% and a standard deviation of about 29%. Concerning the improved DSM blocks, the proposed model predicts Pu with a mean accuracy of 106% and a standard deviation of 10%, whereas the standards EN 1996-1-1 presents a mean accuracy of 124% and a standard deviation of 9%. [less ▲]

Detailed reference viewed: 68 (22 UL)
Peer Reviewed
See detailTranslanguaging practices in early childhood education in Luxembourg
Kirsch, Claudine UL

in Kirsch, Claudine; Duarte, Joana (Eds.) Multilingual approaches for teaching and learning. From acknowledging to capitalizing on multilingualism in European mainstream education. (2020)

Calls for multilingual pedagogies have reached early childhood education and some programmes have been implemented in Europe. However, their focus frequently remains on the majority language and home ... [more ▼]

Calls for multilingual pedagogies have reached early childhood education and some programmes have been implemented in Europe. However, their focus frequently remains on the majority language and home languages are given little space. For multilingual programmes to be inclusive and empowering, professionals need to break with monolingual practices based on monolingual ideologies. The resource-oriented pedagogy of translanguaging which challenges hegemonic practices, is one way in which professionals can give space to all languages, leverage children’s resources and contribute to their development. The present chapter presents the findings of a professional development on multilingual pedagogies in Luxembourg. Data stem from observations, video-recorded activities and interviews with four practitioners, two working in a formal education setting and two in a non-formal one. The findings show that the practitioners developed a positive stance towards translanguaging and multilingual education, learned to design a child-centred and holistic multilingual learning environment and used languages flexibly, deploying translation, code-switching and translanguaging. This dynamic language use facilitated communication, participation, language learning and well-being. There were differences between the practitioners’ flexible language use. The professionals in the school did not use pair talk, made less use of code-switching and used languages more strategically and responsibly than the caregivers in the crèche. [less ▲]

Detailed reference viewed: 44 (0 UL)
Peer Reviewed
See detailTheoretical approaches towards multilingual education
Kirsch, Claudine UL; Duarte

in Kirsch, Claudine; Duarte, Joana (Eds.) Multilingual approaches for teaching and learning. From acknowledging to capitalising on multilingualism in European mainstream education (2020)

Detailed reference viewed: 32 (0 UL)
Peer Reviewed
See detailEarly Language Education in Luxembourg
Kirsch, Claudine UL; Seele, Claudia

in Schwartz, Mila; Prošić-Santovac, Danijela (Eds.) International Handbook of early childhood education (2020)

Detailed reference viewed: 35 (0 UL)
Peer Reviewed
See detailFlexible language use in multilingual early childhood education in Luxembourg: Reflecting on its nature and functions
Kirsch, Claudine UL; Seele, Claudia

in Panagiotopoulou, Argyro; Rosen, Lisa; Strzykala, Jenna (Eds.) Inclusion, Education, and Translanguaging: How to Promote Social Justice in (Teacher) Education? (2020)

Detailed reference viewed: 34 (0 UL)
Peer Reviewed
See detailEffective professional development and sustainability of multilingual approaches
Kirsch, Claudine UL; Duarte, Joana; Palviainen, Åsa

in Kirsch, Claudine; Duarte, Joana (Eds.) Multilingual approaches for teaching and learning_From acknowledging to capitalising on multilingualism in European mainstream education (2020)

Detailed reference viewed: 30 (1 UL)
Full Text
Peer Reviewed
See detailChapter 16 - Cognitive factors associated with gaming disorder
Billieux, Joël UL; Potenza, Marc N.; Maurage, Pierre et al

in Verdejo-Garcia, Antonio (Ed.) Cognition and Addiction (2020)

There is substantial clinical and public health evidence that video gaming, particularly online gaming, can become excessive and lead to psychological distress and functional impairment. This has led to ... [more ▼]

There is substantial clinical and public health evidence that video gaming, particularly online gaming, can become excessive and lead to psychological distress and functional impairment. This has led to the inclusion of gaming disorder as an official mental condition in the International Classification of Diseases, 11th Edition (ICD-11; World Health Organization, 2019). Psychological models recognize the importance of cognitive factors to explain the initiation, development, and maintenance of problematic gaming behaviors. This chapter will summarize some of the known cognitive factors associated with problem gaming and gaming disorder. These cognitions will be divided into two broad categories: (1) cognitive deficits (e.g., impaired executive functioning, hazardous decision-making, or deliberative processes) and (2) cognitive biases (e.g., attentional biases, cognitive distortions, dysfunctional cognitions). This chapter will review and synthesize available research findings and highlight their clinical implications for gaming disorder. The limitations of the research base are considered and some potential avenues for future research are proposed. [less ▲]

Detailed reference viewed: 15 (2 UL)
Full Text
Peer Reviewed
See detailJoint Scheduling and Precoding for Frame-Based Multigroup Multicasting in Satellite Communications
Bandi, Ashok UL; Shankar, Bhavani UL; Chatzinotas, Symeon UL et al

Scientific Conference (2019, December 09)

Recent satellite standards enforce the coding of multiple users’ data in a frame. This transmission strategy mimics the well-known physical layer multigroup multicasting (MGMC). However, typical beam ... [more ▼]

Recent satellite standards enforce the coding of multiple users’ data in a frame. This transmission strategy mimics the well-known physical layer multigroup multicasting (MGMC). However, typical beam coverage with a large number of users and limited frame length lead to the scheduling of only a few users. Moreover, in emerging aggressive frequency reuse systems, scheduling is coupled with precoding. This is addressed in this work, through the joint design of scheduling and precoding for frame-based MGMC satellite systems. This aim is formulated as the maximization of the sum-rate under per beam power constraint and minimum SINR requirement of scheduled users. Further, a framework is proposed to transform the non-smooth SR objective with integer scheduling and nonconvex SINR constraints as a difference-of-convex problem that facilitates the joint update of scheduling and precoding. Therein, an efficient convex-concave procedure based algorithm is proposed. Finally, the gains (up to 50%) obtained by the jointed design over state-of-the-art methods is shown through Monte-Carlo simulations. [less ▲]

Detailed reference viewed: 59 (13 UL)
Full Text
Peer Reviewed
See detailThe Impact of Human Mobility on Edge Data Center Deployment in Urban Environments
Vitello, Piergiorgio UL; Capponi, Andrea UL; Fiandrino, Claudio UL et al

in IEEE Global Communications Conference (GLOBECOM), Waikoloa, HI, USA, 2019 (2019, December)

Multi-access Edge Computing (MEC) brings storage and computational capabilities at the edge of the network into so-called Edge Data Centers (EDCs) to better low-latency applications. To this end ... [more ▼]

Multi-access Edge Computing (MEC) brings storage and computational capabilities at the edge of the network into so-called Edge Data Centers (EDCs) to better low-latency applications. To this end, effective placement of EDCs in urban environments is key for proper load balance and to minimize outages. In this paper, we specifically tackle this problem. To fully understand how the computational demand of EDCs varies, it is fundamental to analyze the complex dynamics of cities. Our work takes into account the mobility of citizens and their spatial patterns to estimate the optimal placement of MEC EDCs in urban environments in order to minimize outages. To this end, we propose and compare two heuristics. In particular, we present the mobility-aware deployment algorithm (MDA) that outperforms approaches that do not consider citizens mobility. Simulations are conducted in Luxembourg City by extending the CrowdSenSim simulator and show that efficient EDCs placement significantly reduces outages. [less ▲]

Detailed reference viewed: 37 (1 UL)
Full Text
Peer Reviewed
See detailDistance-based vertex identification in graphs: The outer multiset dimension
Gil-Pons, Reynaldo; Ramirez Cruz, Yunior UL; Trujillo-Rasua, Rolando et al

in Applied Mathematics and Computation (2019), 363

Detailed reference viewed: 35 (0 UL)