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See detailUniversal health coverage: an urgent need for collaborative learning and technology in primary care
Patel, Kunal D.; Mcloughlin, Clodagh; Lygidakis, Charilaos UL et al

in Education for Primary Care (2017)

Universal health coverage is an achievable goal for all health professionals globally. However, for it to be implemented technology and collaboration are essential. This letter focuses on recently ... [more ▼]

Universal health coverage is an achievable goal for all health professionals globally. However, for it to be implemented technology and collaboration are essential. This letter focuses on recently published recommendations for technology in primary care education in respect to Universal Health Coverage. [less ▲]

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See detailUnpacking Collaboration in Digital History Projects
Kemman, Max UL

Scientific Conference (2017)

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See detailUntersuchungen der instationären Strömungstopologie im Nachlauf einer Seehundvibrisse.
Witte, Matthias; Michael, Mark UL; Brede, Martin et al

in Delgado, A.; Rauh, A.; Lienhart, H. (Eds.) et al Proceedings der 17.GALA-Fachtagung “Lasermethoden in der Strömungsmesstechnik“ (2009)

Die Vibrissen von Seehunden zeichnen sich durch eine komplizierte dreidimensionale Struk- turierung aus. Sie versetzen den Seehund in die Lage, hydrodynamische Nachlaufspuren von Beutefischen zu ... [more ▼]

Die Vibrissen von Seehunden zeichnen sich durch eine komplizierte dreidimensionale Struk- turierung aus. Sie versetzen den Seehund in die Lage, hydrodynamische Nachlaufspuren von Beutefischen zu detektieren. Mit Hilfe von Stereo- μ Piv Messungen an Seehundvibrissen konnte die stationäre Strömungstopologie des Vibrissennachlaufes ermittelt werden. Zum besseren Verständnis der Funktion der Vibrissenstrukturierung ist es notwendig, die instatio- näre Strömungstopologie zu kennen. Durch räumlich und zeitlich hochauflösende numeri- sche Verfahren konnte die instationäre Strömungstopologie im Nachlauf einer Seehund- vibrisse ermittelt werden. [less ▲]

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See detailUsage of Smartphone Data to Derive an Indicator for Collaborative Mobility between Individuals
Toader, Bogdan UL; Sprumont, François UL; Faye, Sébastien UL et al

in ISPRS International Journal of Geo-Information (2017), 6(3), 62

The potential of geospatial big data has been drawing attention for a few years. Despite the larger and larger market penetration of portable technologies (nomadic and wearable devices like smartphones ... [more ▼]

The potential of geospatial big data has been drawing attention for a few years. Despite the larger and larger market penetration of portable technologies (nomadic and wearable devices like smartphones and smartwatches), their opportunities for travel behavior analysis are still relatively unexplored. The main objective of our study is to extract the human mobility patterns from GPS traces in order to derive an indicator for enhancing Collaborative Mobility (CM) between individuals. The first step, extracting activity duration and location, is done using state-of-the-art automated recognition tools. Sensors data are used to reconstruct individual’s activity location and duration across time. For constructing the indicator, in a second step, we defined different variables and methods for specific case studies. Smartphone sensor data are being collected from a limited number of individuals and for one week. These data are used to evaluate the proposed indicator. Based on the value of the indicator, we analyzed the potential for identifying CM among groups of users, such as sharing traveling resources (e.g., carpooling, ridesharing, parking sharing) and time (rescheduling and reordering activities). [less ▲]

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See detailUse of commercial simulation software for analyzing the dynamics of an injection-molding clamp unit
Hostert, Claude UL

Doctoral thesis (2006)

Today, the interest in integrated dynamic analysis of mechatronic systems increases. Different approaches are possible depending on the nature of the system, on the required complexity of the model, or ... [more ▼]

Today, the interest in integrated dynamic analysis of mechatronic systems increases. Different approaches are possible depending on the nature of the system, on the required complexity of the model, or simply on the tools available to the engineer. During this work, the aim was to implement specialized commercial simulation software packages and to combine them in order to simulate the dynamic behavior of mechatronic systems as for example an injection molding machine. The multi-body simulation software is the backbone of the current analysis as it inherently models large non-linear motions. It is possible to account for the flexibility of components in the MBS model if necessary. Furthermore, other simulation codes were used to model the hydraulic and controls systems. The case studies show the interest and the potential of a combined analysis of mechatronic systems. Once the different sub-models, generated with the adequate simulation tool, have been successfully linked and validated by measurements, various scenarios can be simulated and analyzed. The model provides the engineer with an additional insight into the overall system and thus with a better understanding of its dynamic characteristics. The interactions between the subsystems, which may be of very distinctive nature, can be investigated. Generally, it is difficult to predict such relations intuitively. Finally, the model allows to simulate with different design parameters and to asses the effect of modifications to these on the overall performance of the machine. This helps to identify the significant parameters that are crucial for an optimized functioning. [less ▲]

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See detailUsing Bayes' theorem to infer the material parameters of human soft tissue
Hale, Jack UL; Farrell, Patrick; Bordas, Stéphane UL

Presentation (2015, October 21)

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See detailUsing Bayesian inference to recover the material parameters of a heterogeneous hyperelastic body
Hale, Jack UL; Farrell, Patrick; Bordas, Stéphane UL

Scientific Conference (2016)

We present a method for calculating a Bayesian uncertainty estimate on the recovered material parameters of a heterogeneous geometrically non-linear hyperelastic body. We formulate the problem in the ... [more ▼]

We present a method for calculating a Bayesian uncertainty estimate on the recovered material parameters of a heterogeneous geometrically non-linear hyperelastic body. We formulate the problem in the Bayesian inference framework [1]; given noisy and sparse observations of a body, some prior knowledge on the parameters and a parameter-to-observable map the goal is to recover the posterior distribution of the parameters given the observations. In this work we primarily focus on the challenges of developing dimension-independent algorithms in the context of very large inverse problems (tens to hundreds of thousands of parameters). Critical to the success of the method is viewing the problem in the correct infinite- dimensional function space setting [2]. With this goal in mind, we show the use of automatic symbolic differentiation techniques to construct high-order adjoint models [3], scalable maximum a posteriori (MAP) estimators, and efficient low-rank update methods to calculate credible regions on the posterior distribution [4]. [less ▲]

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See detailUsing Complex Problem Solving Simulations for General Cognitive Ability Assessment: the Genetics Lab Framework
Mayer, Hélène; Hazotte, Cyril; Djaghloul, Younes et al

in International Journal of Information Science and Intelligent System (2013), 2(4), 71-88

This paper presents the conception and operation of “the Genetics Lab,” a research platform designed for general intelligence measurement. This tool has been developed and refined to measure cognitive ... [more ▼]

This paper presents the conception and operation of “the Genetics Lab,” a research platform designed for general intelligence measurement. This tool has been developed and refined to measure cognitive skills of students in Luxembourg, Thanks to its generic and clear architecture, “the Genetics Lab” makes a major contribution by addressing technical weaknesses and flaws met with tools previously used to assess intelligence. This new platform can be used as groundwork for other evaluation solutions. In this paper, we explore in depth the main fields of e-assessment such as instructions, localized and multilingual content production and display, traces, and scoring. We also describe how the platform was put into action to create complex simulations and to make data collection resulting from the user’s test a flawless process. This paper is a continuation and extension of earlier work. [less ▲]

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See detailUsing mobile phone data for urban network state estimation
Derrmann, Thierry; Frank, Raphaël UL; Engel, Thomas UL et al

Scientific Conference (2018, June)

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See detailA UX Approach to Privacy and Security: the Impact of User, Contextual and System-Related Factors
Distler, Verena UL; Lallemand, Carine UL; Koenig, Vincent UL

in CHI Workshop Exploring Individual Diffferences in Privacy (2018, April)

This position paper lays out current and future studies which we conduct on the UX aspects of security and privacy, our goal being to understand which factors influence privacy-related decision-making. We ... [more ▼]

This position paper lays out current and future studies which we conduct on the UX aspects of security and privacy, our goal being to understand which factors influence privacy-related decision-making. We advocate using UX design methods in order to study interindividual differences, system-related and contextual factors involved in privacy and security attitudes and behaviors. These results will contribute to user-tailored and personalized privacy initiatives and guide the design of future technologies. [less ▲]

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See detailA UX Approach to Privacy and Security: the Impact of User, Contextual and System-Related Factors
Distler, Verena UL; Lallemand, Carine UL; Koenig, Vincent UL

in CHI Workshop Exploring Individual Diffferences in Privacy (2018, April)

This position paper lays out current and future studies which we conduct on the UX aspects of security and privacy, our goal being to understand which factors influence privacy-related decision-making. We ... [more ▼]

This position paper lays out current and future studies which we conduct on the UX aspects of security and privacy, our goal being to understand which factors influence privacy-related decision-making. We advocate using UX design methods in order to study interindividual differences, system-related and contextual factors involved in privacy and security attitudes and behaviors. These results will contribute to user-tailored and personalized privacy initiatives and guide the design of future technologies. [less ▲]

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See detailA variational formulation of dissipative quasicontinuum methods
Rokos, Ondrej; Beex, Lars UL; Peerlings, Ron et al

in International Journal of Solids and Structures (2016), 102-103

Lattice systems and discrete networks with dissipative interactions are successfully employed as meso-scale models of heterogeneous solids. As the application scale generally is much larger than that of ... [more ▼]

Lattice systems and discrete networks with dissipative interactions are successfully employed as meso-scale models of heterogeneous solids. As the application scale generally is much larger than that of the discrete links, physically relevant simulations are computationally expensive. The QuasiContinuum (QC) method is a multiscale approach that reduces the computational cost of direct numerical simulations by fully resolving complex phenomena only in regions of interest while coarsening elsewhere. In previous work (Beex et al., J. Mech. Phys. Solids 64, 154-169, 2014), the originally conservative QC methodology was generalized to a virtual-power-based QC approach that includes local dissipative mechanisms. In this contribution, the virtual-power-based QC method is reformulated from a variational point of view, by employing the energy-based variational framework for rate-independent processes (Mielke and Roub cek, Rate-Independent Systems: Theory and Application, Springer-Verlag, 2015). By construction it is shown that the QC method with dissipative interactions can be expressed as a minimization problem of a properly built energy potential, providing solutions equivalent to those of the virtual-power-based QC formulation. The theoretical considerations are demonstrated on three simple examples. For them we verify energy consistency, quantify relative errors in energies, and discuss errors in internal variables obtained for different meshes and two summation rules. [less ▲]

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See detailVibration of functionally graded material plates with cutouts & cracks in thermal environment
Rahimabadi, A. A.; Natarajan, S.; Bordas, Stéphane UL

in Key Engineering Materials (2013), 560

In this paper, the effect of a centrally located cutout (circular and elliptical) and cracks emanating from the cutout on the free flexural vibration behaviour of functionally graded material plates in ... [more ▼]

In this paper, the effect of a centrally located cutout (circular and elliptical) and cracks emanating from the cutout on the free flexural vibration behaviour of functionally graded material plates in thermal environment is studied. The discontinuity surface is represented independent of the mesh by exploiting the partition of unity method framework. A Heaviside function is used to capture the jump in the displacement across the discontinuity surface and asymptotic branch functions are used to capture the singularity around the crack tip. An enriched shear flexible 4-noded quadrilateral element is used for the spatial discretization. The properties are assumed to vary only in the thickness direction. The effective properties of the functionally graded material are estimated using the Mori-Tanaka homogenization scheme and the plate kinematics is based on the first order shear deformation theory. The influence of the plate geometry, the geometry of the cutout, the crack length, the thermal gradient and the boundary conditions on the free flexural vibration is numerically studied. © (2013) Trans Tech Publications, Switzerland. [less ▲]

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See detailVicinity Resource Cartography for Delay-Tolerant Networks: a Holistic Perspective
Sandulescu, Gabriel UL; Schaffer, Peter UL; Nadjm-Tehrani, Simin UL

in 2010 IFIP W IRELESS D AYS (2010)

In this paper we propose a distributed algorithm allowing nodes in delay-tolerant networks to construct vicinity resource maps based on past encounters. Our algorithm estimates the availability of the ... [more ▼]

In this paper we propose a distributed algorithm allowing nodes in delay-tolerant networks to construct vicinity resource maps based on past encounters. Our algorithm estimates the availability of the following resources: energy, buffer space, and bandwidth. We then show how a store-carry-forward scheme may benefit from having access to these resource estimates. While knowledge about resources available in the vicinity allows nodes to implement meaningful custodian election strategies, an evaluation of available bandwidth and contact time allows them to carry out adaptive queue management strategies. Thus, such strategies can be approached from a holistic perspective based on the availability of the three resources under consideration in node proximity.We validate our model separately in time-varying and space-varying environments. In addition to synthetic mobility models (random waypoint) we validate our resource estimation in a disaster area mobility model (using Bonn motion traces). We show that by using this information a routing protocol may dramatically improve its delivery rate and energy overhead while keeping delivery latency almost constant. [less ▲]

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See detailVirtual and smoothed finite elements: A connection and its application to polygonal/polyhedral finite element methods
Natarajan, Sundararajan; Bordas, Stéphane UL; Ooi, Ean Tat

in International Journal for Numerical Methods in Engineering (2015), 104(13), 1173-1199

We show both theoretically and numerically a connection between the smoothed finite element method (SFEM) and the virtual element method and use this approach to derive stable, cheap and optimally ... [more ▼]

We show both theoretically and numerically a connection between the smoothed finite element method (SFEM) and the virtual element method and use this approach to derive stable, cheap and optimally convergent polyhedral FEM.We show that the stiffness matrix computed with one subcell SFEM is identical to the consistency term of the virtual element method, irrespective of the topology of the element, as long as the shape functions vary linearly on the boundary. Using this connection, we propose a new stable approach to strain smoothing for polygonal/polyhedral elements where, instead of using sub-triangulations, we are able to use one single polygonal/polyhedral subcell for each element while maintaining stability. For a similar number of degrees of freedom, the proposed approach is more accurate than the conventional SFEM with triangular subcells. The time to compute the stiffness matrix scales with the O.dof s/1:1 in case of the conventional polygonal FEM, while it scales as O.dof s/0:7 in the proposed approach. The accuracy and the convergence properties of the SFEM are studied with a few benchmark problems in 2D and 3D linear elasticity. [less ▲]

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See detailVirtual Coach Reaches Out To Me
Aleksic, Gabrijela UL

Conference given outside the academic context (2013)

Detailed reference viewed: 9 (1 UL)
See detailVirtual Coach Reaches Out To Me
Aleksic, Gabrijela UL

Conference given outside the academic context (2013)

Detailed reference viewed: 13 (0 UL)
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See detailThe virtual node polygonal element method for nonlinear thermal analysis with application to hybrid laser welding
Wu, SC; Peng, X; Zhang, WH et al

in International Journal of Heat & Mass Transfer (2013), 67

The nonlinear heat transfer process occurring during hybrid laser welding was simulated using the Virtual-node Polygonal Element (VPE) method within the framework of the Finite Element Method (FEM). To ... [more ▼]

The nonlinear heat transfer process occurring during hybrid laser welding was simulated using the Virtual-node Polygonal Element (VPE) method within the framework of the Finite Element Method (FEM). To achieve robustness in large-scale welding simulations, a dynamic mesh refinement with quadtree and octree data structures was used in the welding region. Accuracy, convergence and efficiency were verified by solving two and three dimensional problems. It is found that the present VPE can successfully simulate the hybrid laser welding process with good accuracy and convergence. The adaptive refined mesh box can synchronously move with the welding heat source, which dramatically reduces the number of field nodes. Compared with the standard FEM,the VPEM requires only approximately 42% of the total degrees of freedom used in standard FEM for the same accuracy. Furthermore, we compare the computational cost and accuracy of the method to that of the finite element method, the edge based virtual node polygonal element/virtual node method, the edge-based Smoothed Point Interpolation Meshless Method (ES-PIM), the edge-based Element (ES-PIM) the Element Free Galerkin (EFG) method and the Meshless Local Petrove-Galerkin Petrov-Galerkin (MLPG) method. Compared to all those methods, the proposed scheme is found competitive in terms of computational cost versus accuracy, and benefit from a simple implementation. © 2012 Elsevier B.V. All rights reserved. [less ▲]

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See detailVirtual-power-based quasicontinuum methods for discrete dissipative materials
Beex, Lars UL; Bordas, Stéphane UL

Scientific Conference (2016, June)

Detailed reference viewed: 70 (2 UL)
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See detailVirtual-power-based quasicontinuum methods for discrete dissipative materials
Beex, Lars UL

Scientific Conference (2016, June)

In this presentation, the formulation of the virtual-power-based QC framework will be outlined for an elastoplastic truss lattice. Subsequently, the framework is applied to an actual discrete material.

Detailed reference viewed: 54 (3 UL)