References of "2008"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailRegionale Schwerefeldmodellierung durch Slepian- und radiale Basisunktionen
Antoni, M.; Keller, W.; Weigelt, Matthias UL

in Zeitschrift für Vermessungswesen (2008), 133(2), 120--129

Zur Erfassung des statischen und des zeitvariablen Gravitati- onsfeldes der Erde sind seit 2000 bzw. seit 2002 die beiden Satellitenmissionen CHAMP und GRACE im Orbit. Üblicher- weise wird das aus den ... [more ▼]

Zur Erfassung des statischen und des zeitvariablen Gravitati- onsfeldes der Erde sind seit 2000 bzw. seit 2002 die beiden Satellitenmissionen CHAMP und GRACE im Orbit. Üblicher- weise wird das aus den Missionsdaten abgeleitete Gravita- tionsfeld als Summe von Kugelfunktionen dargestellt. Es zeigt sich aber, dass diese global definierten Basisfunktionen nicht in der Lage sind, alle in den Daten enthaltenen lokalen De- tails zu repräsentieren. Der Beitrag stellt zwei Methoden dar, das verbleibende Restsignal durch lokale Basisfunktionen auf- zulösen. Zum einen werden die radialen Basisfunktionen ver- wendet, zum anderen die Slepianfunktionen, die durch Or- thogonalisierung der Kugelflächenfunktionen auf einem vor- gegebenen Teil der Kugeloberfläche entstehen. Werden alle Parameter der radialen Basisfunktionen geschätzt, so erfor- dert das nichtlineare Problem neben den Startwerten auch eine Strahlminimierung, die die Konvergenz der Lösung ver- bessert, und ein Penalty-Verfahren, damit die geschätzten Parameter in einem sinnvollen Intervall fixiert werden. In ei- ner Simulationsstudie werden die erreichbaren Genauigkeiten und der numerische Aufwand beider Funktionensysteme mit- einander verglichen. [less ▲]

Detailed reference viewed: 37 (1 UL)
Full Text
Peer Reviewed
See detailLocal emplacement and global identities in signboard and billboard literacies in urban Gambia
Juffermans, Kasper UL

in Simo Bobda, Augustin (Ed.) Explorations into language use in Africa (2008)

Detailed reference viewed: 121 (0 UL)
See detailJugendforschung im Dialog: Beiträge der INSIDE-Vortragsreihe 2007 zur Jugendforschung
Milmeister, Marianne UL; Willems, Helmut UL

Book published by Universität Luxemburg (2008)

Die Veröffentlichung geht auf die INSIDE-Vortragsreihe 2007 zurück, die ein öffentliches Fachforum für gemeinsamen Informations- und Gedankenaustausch zu Fragen der Jugendforschung an der Universität ... [more ▼]

Die Veröffentlichung geht auf die INSIDE-Vortragsreihe 2007 zurück, die ein öffentliches Fachforum für gemeinsamen Informations- und Gedankenaustausch zu Fragen der Jugendforschung an der Universität Luxemburg etabliert hatte. [less ▲]

Detailed reference viewed: 145 (19 UL)
See detailCaractéristiques sémiotiques de la bande dessinée
Freyermuth, Sylvie UL; Barthe, Hugues (auteur de BD)

Presentation (2008, February 26)

Detailed reference viewed: 77 (3 UL)
See detailRezension von: Manfred Rasch/Kurt Düwell (eds.) (2007). Anfänge und Auswirkungen der Montanunion auf Europa. Die Stahlindustrie in Politik und Wirtschaft. Essen: Klartext
Krebs, Stefan UL

in H-Soz-Kult: Kommunikation und Fachinformation für die Geschichtswissenschaften (2008)

Detailed reference viewed: 224 (1 UL)
See detail„Irland- eine Insel zwischen Schafen und Hightech“
Nienaber, Birte UL

Conference given outside the academic context (2008)

Detailed reference viewed: 59 (1 UL)
Full Text
See detailIV Grid Plugtests: composing dedicated tools to run an application efficiently on Grid'5000
Besseron, Xavier UL; Danjean, Vincent; Gautier, Thierry et al

Presentation (2008, February 12)

Exploiting efficiently the resources of whole Grid'5000 with the same application requires to solve several issues: 1) resources reservation; 2) application's processes deployment; 3) application's tasks ... [more ▼]

Exploiting efficiently the resources of whole Grid'5000 with the same application requires to solve several issues: 1) resources reservation; 2) application's processes deployment; 3) application's tasks scheduling. For the IV Grid Plugtests, we used a dedicated tool for each issue to solve. The N-Queens contest rules imposed ProActive for the resources reservations (issue 1). Issue 2 was solved using TakTuk which allows to deploy a large set of remote nodes. Deployed nodes take part in the deployment using an adaptive algorithm that makes it very efficient. For the 3rd issue, we wrote our application with Athapascan API whose model is based on the concepts of tasks and shared data. The application is described as a data-flow graph using the Shared and Fork keywords. This high level abstraction of hardware gives us an efficient execution with the Kaapi runtime engine using a work-stealing scheduling algorithm to balance the workload between all the distributed processes. [less ▲]

Detailed reference viewed: 26 (1 UL)
Full Text
See detailIntergeo - Interoperable Interactive Geometry for Europe
Kreis, Yves UL; Schandeler, Ingo; Libbrecht, Paul

Scientific Conference (2008, February 01)

Interactive Geometry is a way to improve mathematics education with the help of a computer. Using sophisticated software, sketches and figures can be brought to life, comparable to what movies mean to ... [more ▼]

Interactive Geometry is a way to improve mathematics education with the help of a computer. Using sophisticated software, sketches and figures can be brought to life, comparable to what movies mean to images. Although many examples of helpful activities that were created using Interactive Geometry Software exist, interactive geometry software is still not used regularly in classrooms. In fact, many teachers do not know about the new possibilities, or they do not have access to the necessary resources. The EU-co-funded project Intergeo will attack the three main barriers for a EU-wide adoption of the existing material: missing search facilities, lack of interoperability, and missing quality information. [less ▲]

Detailed reference viewed: 44 (0 UL)
Full Text
Peer Reviewed
See detail3D Object Recognition Using Fully Intrinsic Skeletal Graphs
Aouada, Djamila UL; Krim, Hamid

in International Conference on Computational Imaging, 2008 (2008, February)

Detailed reference viewed: 112 (3 UL)
Full Text
Peer Reviewed
See detailSpaceborne gravimetry and gravity field recovery
Xu, C.; Weigelt, Matthias UL; Sideris, M. G. et al

in Canadian Aeronautics and Space Journal (2008), 53(3/4), 65--75

As an integrated signal of mass transition and distribution, the Earth's gravity senses the inner and outer mass balance of the Earth. However gravity cannot be measured directly in space but can be ... [more ▼]

As an integrated signal of mass transition and distribution, the Earth's gravity senses the inner and outer mass balance of the Earth. However gravity cannot be measured directly in space but can be derived from other measurements obtained by space vehicles. The dedicated gravity field satellite missions CHAMP, GRACE, and GOCE serve as spaceborne gravimeters by utilizing satellite-to-satellite tracking (SST) and satellite gravity gradiometry (SGG) techniques. In this decade of the geopotentials, these missions will serve different purposes with particular spatial and spectral resolutions. This paper introduces the usefulness of these missions, their impacts on the geosciences the measurement principles, and their implementations. These space sensors will provide a significant number of observations during their mission lifespans. Therefore, global gravity field recovery is a computationally demanding task. Several approaches aimed at this goal are discussed, namely the brute-force approach, the space-wise approach, the time-wise approach, and the proposed torus-based semi-analytical approach. The paper addresses the characteristics of each approach and focuses mainly on the torus-based semi-analytical approach, which can be used to derive the gravity field from any geopotential functional. In this approach, the structure of the normal matrix becomes block-diagonal which leads to a powerful and efficient recovery tool through the use of the fast Fourier transform (FFT). Important issues such as downward continuation, interpolation methods, and regularization approaches are also discussed. To demonstrate the feasibility and efficiency of the torus-based semi-analytical approach of gravity field determination in spaceborne gravimetry, disturbing potential data from CHAMP and GRACE and simulated GOCE gravity gradient tensor data are processed. [less ▲]

Detailed reference viewed: 108 (1 UL)
Full Text
See detailStatus quo report on DGS usage
Hendriks, Maxim; Ippersiel, Mathieu; Kortenkamp, Ulrich et al

Report (2008)

Detailed reference viewed: 29 (0 UL)
See detailOccupants using 3D range images
Devarakota, Pandu Ranga Rao UL

Doctoral thesis (2008)

Detailed reference viewed: 44 (9 UL)
Full Text
Peer Reviewed
See detailCommon agency games: Indifference and separable preferences
Attar, Andrea; Majumdar, Dipjyoti; Piaser, Gwenaël UL et al

in Mathematical Social Sciences (2008), 56(1), 75-95

This paper examines the role of direct mechanisms in common agency games. We focus on deterministic contracts and show how the introduction of a separability condition on the preferences of the agent is ... [more ▼]

This paper examines the role of direct mechanisms in common agency games. We focus on deterministic contracts and show how the introduction of a separability condition on the preferences of the agent is sufficient for the Revelation Principle to hold when finite games with generic payoffs are considered. The result goes through without imposing any restriction on the principals’ payoffs. This provides a rationale for the restriction to direct mechanisms even when competition among principals is considered. [less ▲]

Detailed reference viewed: 106 (0 UL)
See detailGrammaire et réécriture en cycle 3 de l’enseignement primaire (2ème partie)
Freyermuth, Sylvie UL

Presentation (2008, January 14)

Detailed reference viewed: 45 (0 UL)
Full Text
See detailNew Devlopments in Gravity Applications and Instruments
Nind, Chris; Niebauer, Tim; MacQueen, Jeff et al

Scientific Conference (2008, January 14)

Detailed reference viewed: 88 (2 UL)
See detailLes pratiques discursives œnophiles entre normativité et appropriation. Contribution à une sociologie des cultures alimentaires
Reckinger, Rachel UL

Doctoral thesis (2008)

Owing to the fact that wine consumption is becoming ever more culturalised, I have adopted a micro-sociological approach to contemporary œnophile discursive practices, in Luxembourg, by concentrating on ... [more ▼]

Owing to the fact that wine consumption is becoming ever more culturalised, I have adopted a micro-sociological approach to contemporary œnophile discursive practices, in Luxembourg, by concentrating on inherent normativity (moral and aesthetic) and ordinary appropriation (ethical and hedonistic). The context for this articulation is provided by wine tasting lessons ‘for beginners’. The analytical tools that food studies offer are pertinent for tracing the historical evolution of œnophile discursive practices – being singularised, aesthetic and reflexive –, viewed through their rationalisation processes (legislative regulation, scientific consolidation and media diffusion). Through this cristallisation, œnophily has brought about a governmentality of consumption ; its concrete institutionalisation, in the form of state-organised evening-classes, conveys a specific type of normativity. It will be shown that the publics of this institution – mainly male and affluent – have both ‘operational’ and ‘hedonistic’ motivations, thus enhancing a form of governmentality and an interior orientation of experiences. Appropriations of the œnophile normativity are reactive – either positively or negatively : interviewees adopt tactical usages of specific dispositions and of tactical courses of action, related to vertical differenciations (social trajectory and position), but also and mainly to horizontal ones (milieus, interactions and experiments carried out through various projects of subjectivation). These dispositions and tactics are linked to the domestic œnophile logics of action – which are active, strategic and hedonistic. Contrasting with the œnophile normativity (focusing on wine), ordinary discursive practices relate to preoccupations with one’s personal and social life, rather than to wine. Nonetheless, it is the aesthetic-based œnophile canonisation that contains essential prerequisites of subjectivation, even if it is appropriated in a hedonistic, socio- or egocentric way. This shows the consubstantial and flexible interweaving of norms and pleasure, leading to a personal and social empowerment (with a potential that is mainly ethical, but also distinctive), via the discursive usage of one particular food item. [less ▲]

Detailed reference viewed: 114 (5 UL)
Peer Reviewed
See detailOutil d’évaluation en langue dans le cadre d’une enquête internationale : tentative de mise à l’épreuve du C-Test.
Artus, Frédérique; Reichert, Monique UL

Scientific Conference (2008, January 10)

Detailed reference viewed: 47 (0 UL)
See detailGrammaire et réécriture en cycle 3 de l’enseignement primaire (Première partie)
Freyermuth, Sylvie UL

Presentation (2008, January 10)

Detailed reference viewed: 43 (0 UL)
Full Text
Peer Reviewed
See detailApproximations of Lovász extensions and their induced interaction index
Marichal, Jean-Luc UL; Mathonet, Pierre UL

in Discrete Applied Mathematics (2008), 156(1), 11-24

The Lovász extension of a pseudo-Boolean function f : {0,1}^n --> R is defined on each simplex of the standard triangulation of [0,1]^n as the unique affine function \hat f : [0,1]^n --> R that ... [more ▼]

The Lovász extension of a pseudo-Boolean function f : {0,1}^n --> R is defined on each simplex of the standard triangulation of [0,1]^n as the unique affine function \hat f : [0,1]^n --> R that interpolates f at the n+1 vertices of the simplex. Its degree is that of the unique multilinear polynomial that expresses f. In this paper we investigate the least squares approximation problem of an arbitrary Lovász extension \hat f by Lovász extensions of (at most) a specified degree. We derive explicit expressions of these approximations. The corresponding approximation problem for pseudo-Boolean functions was investigated by Hammer and Holzman and then solved explicitly by Grabisch, Marichal, and Roubens, giving rise to an alternative definition of Banzhaf interaction index. Similarly we introduce a new interaction index from approximations of \hat f and we present some of its properties. It turns out that its corresponding power index identifies with the power index introduced by Grabisch and Labreuche. [less ▲]

Detailed reference viewed: 93 (1 UL)
Peer Reviewed
See detailLa gestion de l’hétérogénéité de la population au Luxembourg : d’un problème à des potentialités
Noesen, Mélanie; Meyers, Christian UL; Zerbato, Danielle UL et al

Scientific Conference (2008, January)

Detailed reference viewed: 29 (0 UL)