H wie Heimat

Article for general public (2012)

h- and p-adaptivity driven by recovery and residual-based error estimators for PHT-splines applied to time-harmonic acoustics

in Computers and Mathematics with Applications (2018), 77(9), 2369-2395

In this work, we demonstrate the application of PHT-splines for time-harmonic acoustic problems, modeled by the Helmholtz equation. Solutions of the Helmholtz equation have two features: global ... [more ▼]

In this work, we demonstrate the application of PHT-splines for time-harmonic acoustic problems, modeled by the Helmholtz equation. Solutions of the Helmholtz equation have two features: global oscillations associated with the wave number and local gradients caused by geometrical irregularities. We show that after a sufficient number of degrees of freedom is used to approximate global oscillations, adaptive refinement can capture local features of the solution. We compare residual-based and recovery-based error estimators and investigate the performance of -refinement. The simulations are done in the context of recently introduced Geometry Independent Field approximaTion (GIFT), where PHT-splines are only used to approximate the solution, while the computational domain is parameterized with NURBS. This approach builds on the natural adaptation ability of PHT-splines and avoids the re-parameterization of the NURBS geometry during the solution refinement process. [less ▲]

H-infinity dynamic observer design for linear time invariant systems

in 2014 IEEE 53rd Annual Conference on Decision and Control (CDC), Los Angeles, USA (2014, December)

This paper proposes an H-infinity dynamic observer (DO) for a class of linear time invariant (LTI) systems in the presence of disturbances. It generalizes the existing results on the proportional observer ... [more ▼]

This paper proposes an H-infinity dynamic observer (DO) for a class of linear time invariant (LTI) systems in the presence of disturbances. It generalizes the existing results on the proportional observer (PO), the proportional integral observer (PIO) and the DO. The design method is derived from a new formulation of linear matrix inequality (LMI), based on the solutions of the algebraic constraints obtained from the unbiasedness conditions of the estimation error. A numerical example is provided to show the applicability and performances of our observer. [less ▲]

H2 Norm Based Network Volatility Measures

in The proceedings of the American Control Conference (2014)

Motivated by applications in biology and economics, we propose new volatility measures based on the H2 system norm for linear networks stimulated by independent or correlated noise. We identify critical ... [more ▼]

Motivated by applications in biology and economics, we propose new volatility measures based on the H2 system norm for linear networks stimulated by independent or correlated noise. We identify critical links in a network, where relatively small improvements can lead to large reductions in network volatility measures. We also examine volatility measures of individual nodes and their dependence on the topological position in the network. Finally, we investigate the dependence of the volatility on different network interconnections, weights of the edges and other network properties. Hence in an intuitive and efficient way, we can identify critical links, nodes and interconnections in network which can shed light in the network design to make it more robust. [less ▲]

H2020 PROJECT CEASEVAL. Evaluation of the Common European Asylum System under Pressure and Recommendations for Further Development

Poster (2018)

Within CEASEVAL, the University of Luxembourg leads Work Package 4 (WP4) on “Borders and the Mobility of Migrants”. The aim of WP4 is to develop a framework to analyse the interactions between borders and ... [more ▼]

Within CEASEVAL, the University of Luxembourg leads Work Package 4 (WP4) on “Borders and the Mobility of Migrants”. The aim of WP4 is to develop a framework to analyse the interactions between borders and the mobility of migrants (asylum seekers, refugees and irregular migrants), thus also addressing the relation between asylum systems and Schengen regime. In order to do so, WP4 investigates the functioning of the internal and external EU borders in the governance of migrants’ mobility by looking specifically at the ways in which bordering processes are implemented when confronted with the mobility of migrants. The research draws from an extensive empirical study in 7 different countries: France, Germany, Greece, Hungary, Luxembourg, Spain and Turkey. Qualitative interviews with migrants (asylum seekers, refugees and irregular migrants) and institutional actors (border agents, policymakers, representatives of institutions, etc.), as well as ethnographic observations of border agencies and border points are conducted in these case studies. The objectives of this qualitative fieldwork are to identify mobility trajectories, understand how these are shaped by border policies, and compare bordering processes. The work package will result in 7 country reports (one for each case study), a comparative report, a policy brief, and an online interactive map. [less ▲]

Das habe ich noch nie versucht, also bin ich völlig sicher dass ich es schaffe!: Selbstwirksamkeit und wahrgenommene Kompetenz von Lehramtstudierenden im Umgang mit Schülern mit sonderpädagogischem Förderbedarf

Scientific Conference (2015)

Haben die Frauen die Luxemburger Monarchie gerettet? Diskurse über Frauen im Kontext der Einführung des Frauenwahlrechts

in Frieseisen, Claude; Moes, Régis; Polfer, Michel (Eds.) et al Le suffrage universel au Luxembourg et en Europe. Actes du colloque du 27/28 janvier 2020 à la Chambre des Députés (2021)

Habilitation Thesis

Dissertation and these (2002)

Habilyzer: Empowering Office Workers to Investigate their Working Habits using an Open-Ended Sensor Kit

in Proceedings of the Extended Abstracts of the 2022 CHI Conference on Human Factors in Computing Systems (2022, April)

Office work presents health and wellbeing challenges, triggered by unhealthy working habits or environmental factors. While technologies for vitality in the office context gain popularity, they are often ... [more ▼]

Office work presents health and wellbeing challenges, triggered by unhealthy working habits or environmental factors. While technologies for vitality in the office context gain popularity, they are often solution-focused and fall short in acknowledging personal needs. Building on approaches from personal informatics, we see value in opening up the design space of tracking and sensing technologies for office workers. We designed and deployed an open-ended sensor kit and conducted two complementary studies to investigate the value of empowering office workers to investigate their own working habits. Findings show that Habilyzer triggers curiosity about working habits, and wireless sensors contribute to inquire into those habits, possibly supported by additional tools. We contribute new insights into how an open-ended sensor kit can be designed to support self-tracking practices and underlying reflections in the underexplored context of office work. It is an alternative approach to workplace vitality, moving from solution-oriented technologies to inquiry-enabling tools. [less ▲]

Habitat et qualité de vie à l’ère industrielle

Learning material (2022)