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See detail30. Symposium Klinische Psychologie und Psychotherapie, Abstractband
Vögele, Claus UL

Book published by University of Luxembourg (2012)

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See detail§§ 325 bis 329 HGB zur Publizität der Rechnungslegung
Zetzsche, Dirk Andreas UL

Book published by Hachmeister/Kahle/Mock/Schüppen (2017)

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See detail§ 36. Die Pädagogik
Oelkers, Jürgen; Tröhler, Daniel UL

in Holzhey, Helmut; Mudroch, Vilem (Eds.) Die Philosophie des 18. Jahrhunderts 5/1+2: Heiliges Römische Reich Deutscher Nation. Schweiz. Nord- und Osteuropa (2014)

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See detail3D Beamforming for Spectral Coexistence of Satellite and Terrestrial Networks
Sharma, Shree Krishna UL; Chatzinotas, Symeon UL; Grotz, Joel et al

in IEEE Vehicular Technology Conference 2015 (2015, September)

Satellite communication (SatCom) is facing a spectrum scarcity problem due to the limited available exclusive spectrum and the high demand of the broadband satellite services. In this context, there has ... [more ▼]

Satellite communication (SatCom) is facing a spectrum scarcity problem due to the limited available exclusive spectrum and the high demand of the broadband satellite services. In this context, there has been an increasing interest in the satellite community to exploit the non-exclusive Ka-band spectrum in order to enhance the spectral efficiency of future broadband satellite systems. Herein, we propose a novel concept of enabling the spectral coexistence of satellite and terrestrial networks using three dimensional (3D) beamforming, which exploits the elevation dimension in addition to the commonly used azimuth dimension. The proposed beamforming solution is employed in a Multiple-Input Low Noise Block Downconverter (MLNB) based Feed Array Reflector (FAR) in contrast to the widely used Uniform Linear Array (ULA) structure. Within the employed antenna structure, the performance of the proposed beamforming solution is evaluated considering different feed arrangements. Finally, a database-assisted approach and two blind approaches are suggested for the effective implementation of the proposed solutions. [less ▲]

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See detail3D Crack Detection Using an XFEM Variant and Global Optimization Algorithms
Agathos, Konstantinos UL; Chatzi, Eleni; Bordas, Stéphane UL

Scientific Conference (2016, May)

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See detail3D DEM – FEM Coupling to Analyse the Tractive Performance of Different Tire Treads in Soil
Michael, Mark UL; Peters, Bernhard UL

in Idelsohn, S; Papadrakakis, M; Schrefler, B (Eds.) Computational Methods for Coupled Problems in Science and Engineering V (2013, June)

This contribution investigates the tractive performance of different tire treads on granular terrain by an efficient combination of the Discrete Element Method (DEM) and the Finite Element Method (FEM ... [more ▼]

This contribution investigates the tractive performance of different tire treads on granular terrain by an efficient combination of the Discrete Element Method (DEM) and the Finite Element Method (FEM). The proposed coupling method has been shown to be a sufficient technique when resolving the different length scales involved in engineering problems dealing with granular assemblies in contact with deformable bodies [1][2]. Herein, the extended discrete element method (XDEM) is used to describe the dynamics of the granular assembly. Thereby the discrete approach accounts for the motion and forces of each grain individually. On the other hand, the finite element method accurately predicts the deformations and stresses acting within the tire tread. Hence, the simulation domain occupied by the tire is efficiently described as a continuous entity. The coupling of both method is based on the interface shared by the two spatially separated domains. The interface coupling enables to apply a contact model fitting the particular contact behaviour between the grains and the tread surface. Thus, contact forces develop at the interface and propagate into each domain. The coupling method enables to capture both responses simultaneously. Each grain in contact with the tread surface generates a contact force which it reacts on repulsively. The contact forces sum up over the surface and cause the tire tread to deform. The resultant stresses are then again recognised by the granular assembly. The coupling method compensates quite naturally the shortages of both numerical methods. It further employs a fast contact detection algorithm to spare valuable computation time [1]. The proposed DEM-FEM Coupling technique was employed to study the tractive performance of four different tire treads on a soil layer of the material sand. The simulations were conducted in accordance to the experimental measurements undertaken by Shinone et al. [3]. The contact forces at the surface of smooth, lug, rib and block tread patterns are captured by 3D simulations of different slip values of each tire tread. The simulation results are used to analyse the gross tractive effort, running resistance and drawbar pull of the different tread patterns in sand. [less ▲]

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See detail3D fatigue fracture modeling by isogeometric boundary element methods
Peng, Xuan; Atroshchenko, Elena; Kerfriden, Pierre et al

Scientific Conference (2016, April 01)

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See detail3D Mixed Invariant and its Application on Object Classification
Feng, Shuo; Aouada, Djamila UL; Krim, Hamid et al

in IEEE International Conference on Acoustics, Speech and Signal Processing, 2007. ICASSP 2007 (2007, April)

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See detail3D Modellierung von Festbettreaktoren mit Hilfe der XDEM
Hoffmann, Florian UL

Presentation (2013, July 05)

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See detail3D Modelling of bored tunnels
Van Baars, Stefan UL

in Brinkgreve (Ed.) Proc. Int. Symposium Beyond 2000 in Computational Geotechnics (1999)

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See detail3D object following based on visual information for Unmanned Aerial Vehicles
Mondragón, I. F.; Campoy, P.; Olivares Mendez, Miguel Angel UL et al

in Robotics Symposium, 2011 IEEE IX Latin American and IEEE Colombian Conference on Automatic Control and Industry Applications (LARC) (2011)

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See detail3D Object Recognition Using Fully Intrinsic Skeletal Graphs
Aouada, Djamila UL; Krim, Hamid

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

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See detail3D pose estimation based on planar object tracking for UAVs control
Mondragon, Ivan F.; Campoy, Pascual; Martinez, Carol et al

in Proccedings of IEEE International Conference on Robotics and Automation (ICRA) (2010)

This article presents a real time Unmanned Aerial Vehicles UAVs 3D pose estimation method using planar object tracking, in order to be used on the control system of a UAV. The method explodes the rich ... [more ▼]

This article presents a real time Unmanned Aerial Vehicles UAVs 3D pose estimation method using planar object tracking, in order to be used on the control system of a UAV. The method explodes the rich information obtained by a projective transformation of planar objects on a calibrated camera. The algorithm obtains the metric and projective components of a reference object (landmark or helipad) with respect to the UAV camera coordinate system, using a robust real time object tracking based on homographies. The algorithm is validated on real flights that compare the estimated data against that obtained by the inertial measurement unit IMU, showing that the proposed method robustly estimates the helicopter's 3D position with respect to a reference landmark, with a high quality on the position and orientation estimation when the aircraft is flying at low altitudes, a situation in which the GPS information is often inaccurate. The obtained results indicate that the proposed algorithm is suitable for complex control tasks, such as autonomous landing, accurate low altitude positioning and dropping of payloads. [less ▲]

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See detailA 3D shear material damping model for man-made vibrations of the ground
Macijauskas, Darius UL; Van Baars, Stefan UL

in 13th Baltic Sea Region Geotechnical Conference (2016, September)

Man-made vibrations from different types of sources are usually measured on the surface of the ground or building. The measured signal is always the superposition of all travelling basic waves. For a ... [more ▼]

Man-made vibrations from different types of sources are usually measured on the surface of the ground or building. The measured signal is always the superposition of all travelling basic waves. For a homogeneous half space there are three basic waves – the Compressional (P-wave), Shear (S-wave) and Rayleigh wave (R-wave). Depending on the measuring equipment, only the accelerations or velocities in time of the superposed wave can be measured, but not the distribution of the individual basic waves. Additional problems are that each of the basic waves has its own velocity, besides the body and surface waves have different attenuation laws. By using the rules of superposition of harmonic waves and also the propagation laws of the P-, S- and R-waves, it should be theoretically possible to split the measured superposed signal into the basic waves, because mathematically a system of equations can be assembled which describes the displacements at multiple measuring points in time. In this paper this problem has been solved for a homogenous, elastic and isotropic soil, which is disturbed by a harmonically oscillating disc on the surface. A numerical simulation was performed using a finite element method. The displacements in time were recorded in 10 points on the surface and a system of superposed equations was assembled and solved. The findings prove that each of the three basic waves has its own phase shift with the source, something which was not known before. [less ▲]

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See detail3D Skeleton based Head Detection and Tracking using Range Images
Devarakota, Pandu UL; Castillo-Franco, Marta; Ginhoux, Romuald et al

in IEEE Transactions on Vehicular Technology (2009), 58(8), 4064-4077

Vision-based 3-D head detection and tracking systems have been studied in several applications like video surveillance, face-detection systems, and occupant posture analysis. In this paper, we present the ... [more ▼]

Vision-based 3-D head detection and tracking systems have been studied in several applications like video surveillance, face-detection systems, and occupant posture analysis. In this paper, we present the development of a topology-based framework using a 3-D skeletal model for the robust detection and tracking of a vehicle occupant's head position from low-resolution range image data for a passive safety system. Unlike previous approaches to head detection, the proposed approach explores the topology information of a scene to detect the position of the head. Among the different available topology representations, the Reeb graph technique is chosen and is adapted to low-resolution 3-D range images. Invariance of the graph under rotations is achieved by using a Morse radial distance function. To cope with the particular challenges such as the noise and the large variations in the density of the data, a voxel neighborhood connectivity notion is proposed. A multiple-hypothesis tracker (MHT) with nearest-neighbor data association and Kalman filter prediction is applied on the endpoints of the Reeb graph to select and filter the correct head candidate out of Reeb graph endpoints. A systematic evaluation of the head detection framework is carried out on full-scale experimental 3-D range images and compared with the ground truth. It is shown that the Reeb graph topology algorithm developed herein allows the correct detection of the head of the occupant with only two head candidates as input to the MHT. Results of the experiments demonstrate that the proposed framework is robust under the large variations of the scene. The processing requirements of the proposed approach are discussed. It is shown that the number of operations is rather low and that real-time processing requirements can be met with the proposed method. [less ▲]

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See detail3D Time-Of-Flight Camera System and Position/Orientation Calibration Method Therefor
Garcia Becerro, Frederic UL; Grandidier, Frederic; Mirbach, Bruno et al

Patent (2011)

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See detail3D visualization of archaeological uncertainty
Sifniotis, M.; Jackson, B. J. C.; Mania, K. et al

in Proc. ACM Symposium on Applied Perception (2010)

By uncertainty, we define an archaeological expert's level of confidence in an interpretation deriving from gathered evidence. Archaeologists and computer scientists have urged caution in the use of 3D ... [more ▼]

By uncertainty, we define an archaeological expert's level of confidence in an interpretation deriving from gathered evidence. Archaeologists and computer scientists have urged caution in the use of 3D for archaeological reconstructions because the availability of other possible hypotheses is not always being acknowledged. This poster presents a 3D visualization system of archaeological uncertainty. [less ▲]

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