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See detailCARRIER GRAPHS FOR REPRESENTATIONS OF THE RANK TWO FREE GROUP INTO ISOMETRIES OF HYPERBOLIC THREE SPACE
Tan, Ser Peow; Xu, Binbin UL

E-print/Working paper (2018)

Carrier graphs were first introduced for closed hyperbolic 3-manifolds by White. In this paper, we first generalize this definition to carrier graphs for representations of a rank two free group into the ... [more ▼]

Carrier graphs were first introduced for closed hyperbolic 3-manifolds by White. In this paper, we first generalize this definition to carrier graphs for representations of a rank two free group into the isometry group of hyperbolic three space. Then we prove the existence and the finiteness of minimal carrier graphs for those representations which are discrete, faithful and geometrically finite, and more generally, those that satisfy certain finiteness conditions first introduced by Bowditch. [less ▲]

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See detailStrain and Damage Self-Sensing of BFRP Laminates Fabricated with CNFs/Epoxy Composites under Tension
Wang, Y.L; Wang, Y.S.; Wan, B.L. et al

in Composites. Part A, Applied Science and Manufacturing (2018)

This study investigated the strain and damage self-sensing capabilities of basalt fiber reinforced polymer (BFRP) laminates fabricated with carbon nanofibers (CNFs)/epoxy composites subjected to tensile ... [more ▼]

This study investigated the strain and damage self-sensing capabilities of basalt fiber reinforced polymer (BFRP) laminates fabricated with carbon nanofibers (CNFs)/epoxy composites subjected to tensile loadings. The conduction mechanisms based on the tunnel conduction and percolation conduction theories as well as the damage evolution were also explored. A compensation circuit with a half-bridge configuration was proposed. The results indicated the resistivity of the CNFs/BFRP laminates and CNFs/epoxy composites exhibited similar change rule, indicating that the conductive networks of CNFs/BFRP laminates were governed by CNFs/epoxy composites. With the increase of strain under monotonic tensile loading, the electrical resistance response could be classified into three stages corresponding to different damage modes. This confirmed CNFs/BFRP laminates have excellent self-sensing abilities to monitor their internal damages. Moreover, stable and repeatable strain self-sensing capacity of the CNFs/BFRP laminates was verified under cyclic tensile loading because the electrical resistance varied synchronously with the applied strain. [less ▲]

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See detailReal-time Model Predictive Control for Aerial Manipulation
Dentler, Jan Eric UL

Doctoral thesis (2018)

The rapid development in the field of Unmanned Aerial Vehicles (UAVs) is driven by new applications in agriculture, logistics, inspection and smart manufacturing. The future keys in these domains are the ... [more ▼]

The rapid development in the field of Unmanned Aerial Vehicles (UAVs) is driven by new applications in agriculture, logistics, inspection and smart manufacturing. The future keys in these domains are the abilities to autonomously interact with the environment and with other robotic systems. This thesis is providing control engineering solutions to contribute to these key capabilities. The first step of this thesis is to develop an understanding of the dynamic behavior of UAVs. For this purpose, dynamic and kinematic models are presented to describe a UAV's motion. This includes a kinematic model which is suitable for off-the-shelf UAVs and combines full 360° heading operation with a low computational complexity. The presented models are subsequently used to develop a nonlinear model predictive control NMPC strategy. In this context, the performance of several NMPC solvers and inequality constraint handling techniques is evaluated. The real-time capability and NMPC performance are validated with real AR.Drone 2.0 and DJI M100 quadrotors. This includes collision avoidance and advanced tracking scenarios. The design work-flow for the related control objectives and constraints is presented accordingly. As a next step, this UAV NMPC strategy is extended for a UAV with attached robotic arm. For this purpose, the forward kinematics of the robotic arm are developed and combined with the kinematic model of the UAV. The resulting NMPC strategy is validated in a grasping scenario with a real aerial manipulator. The final step of this thesis is the NMPC of cooperating UAVs. The computational complexity of such scenarios conflicts directly with the fast UAV dynamics. In addition, control objectives and system topologies can dynamically change. To address these challenges, this thesis presents the DENMPC software framework. DENMPC provides a computationally efficient central NMPC strategy that allows changing the control scenario at runtime. This is finally stated in the control of a real cooperative aerial manipulation scenario. [less ▲]

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See detailIntegrative analysis of mitochondrial changes in Parkinson’s disease
Glaab, Enrico UL

Presentation (2018, July 16)

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See detailRoundtable 'Humanities in the mirror: writing Jewish history in a digital key'
Zaagsma, Gerben UL

Presentation (2018, July 15)

Participation in a roundtable discussion on Jewish History and digital Humanities.

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See detailMagnetic neutron scattering on bulk ferromagnets
Michels, Andreas UL

Presentation (2018, July 12)

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See detailBook presentation: Borderland Studies Meets Child Studies. A European Encounter
Venken, Machteld UL

Scientific Conference (2018, July 11)

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See detailVisual emulation for Ethereum's virtual machine
Norvill, Robert UL; Fiz Pontiveros, Beltran UL; State, Radu UL et al

in NOMS 2018 - 2018 IEEE/IFIP Network Operations and Management Symposium (2018, July 09)

In this work we present E-EVM, a tool that emulates and visualises the execution of smart contracts on the Ethereum Virtual Machine. By working with the readily available bytecode of smart contracts we ... [more ▼]

In this work we present E-EVM, a tool that emulates and visualises the execution of smart contracts on the Ethereum Virtual Machine. By working with the readily available bytecode of smart contracts we are able to display the program's control flow graph, opcodes and stack for each step of contract execution. This tool is designed to aid the user's understanding of the Etheruem Virtual Machine as well as aid the analysis of any given smart contract. As such, it functions as both an analysis and a learning tool. It allows the user to view the code in each block of a smart contract and follow possible control flow branches. It is able to detect loops and suggest optimisation candidates. It is possible to step through a contract one opcode at a time. E-EVM achieved an average of 85.6% code coverage when tested. [less ▲]

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See detailDephasing in a Mach-Zehnder Interferometer by an Ohmic Contact
Idrisov, Edvin UL; Levkivskyi, Ivan; Sukhorukov, Eugene

in Physical Review Letters (2018)

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See detailInfluence of pubic symphysis stiffness on pelvis stress distribution during single leg stance
Ricci, Pierre-Louis UL; Maas, Stefan UL; Gerich, Torsten et al

Poster (2018, July 09)

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See detailThe Attacker Does not Always Hold the Initiative: Attack Trees with External Refinement
Horne, Ross James UL; Mauw, Sjouke UL; Tiu, Alwen

in Proc.\ 5th International Workshop on Graphical Models for Security (GraMSec'18) (2018, July 08)

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See detailDeveloping early number competencies through games played in school and at home
Tinnes-Vigne, Mélanie UL; Poncelet, Débora UL; de Chambrier, Anne-Françoise et al

in Bergqvist, Ewa; Österholm, Magnus; Granberg, Carina (Eds.) et al Proceedings of the 42nd Conference of the International Group for the Psychology of Mathematics Education (2018, July 07)

Most research studies show that initial number knowledge constitutes the basis for understanding several major principles of mathematics. Moreover, early number competencies are considered as strong ... [more ▼]

Most research studies show that initial number knowledge constitutes the basis for understanding several major principles of mathematics. Moreover, early number competencies are considered as strong predictors of mathematics outcomes at the end of the first grade and even later on (Jordan, Kaplan, Ramineni & Locuniak, 2009). In preschool, the development of these competencies should obviously not give rise to formal learning but is developed through significant activities. However, while everyday situations offer significant contexts, they are still not sufficient to develop the basic number competencies necessary for first grade children (Cannon & Ginsburg, 2008). Adults have to create opportunities to learn mathematical competencies. Mathematical games can meet this requirement. The MathPlay project aims to develop early number competencies through games implemented in school and/or at home. According to the literature, early number competencies consist in counting, conservation ability, magnitude comparison, and (de)composition of numbers. To develop these competencies, we decided to adapt 8 well-known family games. To evaluate the effect of this play-based approach on the development of number competencies, an instrument was created and validated. A quasi-experimental research design (pre/post-test) was implemented in four countries: Luxembourg, Belgium, France and Switzerland. Seven hundred and twenty-five children from all these countries participated in this study. They were divided into one control group and one experimental group with two treatment conditions, X1 (with games at school), and X2 (with games both at school and at home). The post-test was administrated at two moments: just after the intervention and eight weeks later. Data is currently being analysed. This communication will present the first outcomes and will answer our research question: what is the immediate and deferred effect of this play-based approach (X1-X2) on students’ number competencies? [less ▲]

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See detailParent's attitudes towards mathematics, home math-related activities and their effect on preschoolers'skills in early numeracy
Poncelet, Débora UL; Tazouti, Youssef; Baye, Ariane et al

in Berqvist, Ewa; Österholm, Magnus; Granberg, Carina (Eds.) et al Proceedings of the 42nd Conference of the International Group for the Psychology of Mathematics Education (2018, July 07)

Detailed reference viewed: 28 (0 UL)