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Boots, Jelle (author), Spronck, J.W. (author), van Ostayen, R.A.J. (author), Lampaert, S.G.E. (author)Ferrofluid pocket bearings are interesting for fast and precise positioning systems thank to the absence of stick-slip, the low viscous friction and their cost-effective nature. However, the characteristics of the bearing change due to over(de)compression since air escapes out of the enclosed pocket. This article presents an experimentally...journal article 2019
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Schut, I.M. (author), Pasma, J.H. (author), De Veij Mestdagh, J.C. (author), van der Kooij, H. (author), Schouten, A.C. (author)To unravel the underlying mechanisms of human balance control, system identification techniques are applied in combination with dedicated perturbations, like support surface translations. However, it remains unclear what the optimal amplitude and number of repetitions of the perturbation signal are. In this study we investigated the effect of...journal article 2019
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Du, Shenglan (author), Lindenbergh, R.C. (author), Ledoux, H. (author), Stoter, J.E. (author), Nan, L. (author)Laser scanning is an effective tool for acquiring geometric attributes of trees and vegetation, which lays a solid foundation for 3-dimensional tree modelling. Existing studies on tree modelling from laser scanning data are vast. However, some works cannot guarantee sufficient modelling accuracy, while some other works are mainly rule-based and...journal article 2019
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Mao, X. (author), Visser, P.N.A.M. (author), van den IJssel, J.A.A. (author)Precise orbit determination was investigated for a satellite constellation comprised of two different missions, the CHAllenging Minisatellite Payload (CHAMP) satellite and the Gravity Recovery And Climate Experiment (GRACE) twin satellites. The orbital planes of these two missions aligned closely during March to May 2005, allowing precise...journal article 2019
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Mao, X. (author), Visser, P.N.A.M. (author), van den IJssel, J.A.A. (author)Baseline determination for the European Space Agency Swarm magnetic field mission is investigated. Swarm consists of three identical satellites -A, -B and -C. The Swarm-A and -C form a pendulum formation whose baseline length varies between about 30 and 180 km. Swarm-B flies in a higher orbit, causing its orbital plane to slowly rotate with...journal article 2019
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Mohammadi, Majid (author)Ontology alignment systems are evaluated by various performance scores, which are usually computed by a ratio related directly to the frequency of the true positives. However, such ratios provide little information regarding the uncertainty of the overall performance of the corresponding systems. The comparison is also drawn merely by the...journal article 2019
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Ssenyunzi, Richard Cliffe (author), Oruru, Bosco (author), D'ujanga, Florence Mutonyi (author), Realini, Eugenio (author), Barindelli, Stefano (author), Tagliaferro, Giulio (author), van de Giesen, N.C. (author)The Global Navigation Satellite System (GNSS) can be used to derive accurately the Zenith Tropospheric Delay (ZTD) under all-weather conditions. The derived ZTDs play a vital role in climate studies, weather forecasting and are operationally assimilated into numerical weather prediction models. In this study, variations and statistical...journal article 2019
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Saikumar, N. (author), Sinha, Rahul Kumar (author), Hassan HosseinNia, S. (author)This paper presents a novel 'Constant in gain Lead in phase' (CgLp) element using nonlinear reset technique. PID is the industrial workhorse even to this day in high-tech precision positioning applications. However, Bode's gain phase relationship and waterbed effect fundamentally limit performance of PID and other linear controllers. This...journal article 2019
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Teunissen, P.J.G. (author), Khodabandeh, A. (author)A new integer-estimable GLONASS FDMA model is studied and analysed. The model is generally applicable, and it shows a close resemblance with the well-known CDMA models. The analyses provide insights into the performance characteristics of the model and concern a variety of different ambiguity-resolution critical applications. This will be done...journal article 2019
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Teunissen, P.J.G. (author)We introduce a new formulation of the double-differenced GLONASS FDMA model. It closely resembles that of CDMA-based systems and it guarantees the estimability of the newly defined GLONASS ambiguities. The formulation is made possible because of our defining new concept of integer-estimability and the analytical construction of a special...journal article 2019
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Valério, D.P.M.O. (author), Saikumar, N. (author), Ahmadi Dastjerdi, A. (author), Karbasizadeh, Nima (author), Hassan HosseinNia, S. (author)A controller with the frequency response of a complex order derivative may have a gain that decreases with frequency, while the phase increases. This behaviour may be desirable to ensure simultaneous rejection of high-frequency noise and robustness to variations of the open-loop gain. Implementations of such complex order controllers found in...journal article 2019
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Dagalaki, Vasiliki (author)Evolution of coastline position under the influence of natural and anthropogenic processes is directly linked to the development of seaside societies. In the context of coastal zone management, process-based morphodynamic models are often used topredict coastline evolution and support the decision-making process...master thesis 2018
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Boots, Jelle (author)Ferrofluid bearings provide a cheap and passive alternative to contactless bearings such as magnetic bearings and fluid bearings. The absence of stick-slip and the low viscous friction make them interesting for high precision applications. Despite the theoretical models available in literature, the number of design rules for ferrofluid bearings...master thesis 2018
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Salman, Yusuf (author)The high-tech industry is pushing the motion system technology towards faster, more precise and more robust system. One of the keys to this growing demand is the advancement of motion control. To this day, Proportional-Integral-Derivative (PID) has been the workhorse for the industry system control. This is because PID is simple to design and...master thesis 2018
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Kishore Kumar, Rushil (author)This thesis presents the most energy-efficient BJT-based CMOS temperature-to-digital converter (TDC) reported to date. It is based on a continuous-time front-end, which avoids the kT/C noise limit incurred by previous discrete-time (switched-capacitor) front-ends. An energy-efficient capacitively-coupled instrumentation amplifier (CCIA) boosts...master thesis 2018
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Florijn, Floris Jan (author)Computer vision has been on the rise over the last decades. The applications of computer vision are mostly found within the domain of robotics and Unmanned Aerial Vehicle's. The use of computer visions in precision industry is new and offers both opportunities and challenges. In high performance precision systems the demands on sensors is set...master thesis 2018
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Krietemeyer, A. (author), ten Veldhuis, Marie-claire (author), van der Marel, H. (author), Realini, Eugenio (author), van de Giesen, N.C. (author)Dual-frequency Global Navigation Satellite Systems (GNSSs) enable the estimation of Zenith Tropospheric Delay (ZTD) which can be converted to PrecipitableWater Vapor (PWV). The density of existing GNSS monitoring networks is insufficient to capture small-scale water vapor variations that are especially important for extreme weather...journal article 2018
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van Dam, Laurens (author)The demand for higher precision arithmetic is increasing due to the rapid development of new computing paradigms. The novel posit number representation system, as introduced by John L. Gustafson, claims to be able to provide more accurate answers to mathematical problems with equal or less number of bits compared to the well-established IEEE 754...master thesis 2018
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Viëtor, Silvan (author)Actuator self-heating limits achievable force and can cause unwanted structural deformations that adversely affect the accuracy in precision actuation systems. This is especially apparent in quasi-static applications that require the actuator to maintain a stable position over an extended period. As a solution, we propose the use of Tunable...master thesis 2018
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Krikken, André (author)The thesis discusses the design of the secondary mirror support structure for the deployable space telescope. In the thesis the entire support system is considered, including system layout and mirror interface. A selection of hinge concepts were identified and final concepts were selected in trade-offs. The mid hinge was selected to be an...master thesis 2018