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Ribeiro, M.J. (author), Ellerbroek, Joost (author), Hoekstra, J.M. (author)Current predictions for future operations with drones estimate traffic densities orders of magnitude higher than any observed in manned aviation. Such densities call for further research and innovation, in particular, into conflict detection and resolution without the need for human intervention. The layered airspace concept, where aircraft...journal article 2022
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Hoekstra, J.M. (author), Ellerbroek, Joost (author)Purpose of Review A lot of research into decentralised, state-based conflict detection and resolution, or detect and avoid algorithms has been executed. This paper explains the essential properties of state-based conflict detection and reviews the work in the context of applications for not only manned but also unmanned aerial vehicles, where...journal article 2021
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Metz, I.C. (author), Ellerbroek, Joost (author), Mühlhausen, Thorsten (author), Kügler, Dirk (author), Hoekstra, J.M. (author)Bird strike prevention in civil aviation has traditionally focused on the airport perimeter. Since the risk of especially damaging bird strikes outside the airport boundaries is rising, this paper investigates the safety potential of operational bird strike prevention involving pilots and controllers. In such a concept, controllers would be...journal article 2021
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Doole, M.M. (author), Ellerbroek, Joost (author), Knoop, V.L. (author), Hoekstra, J.M. (author)Large-scale adoption of drone-based delivery in urban areas promise societal benefits with respect to emissions and on-ground traffic congestion, as well as potential cost savings for drone-based logistic companies. However, for this to materialise, the ability of accommodating high volumes of drone traffic in an urban airspace is one of the...journal article 2021
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Metz, I.C. (author), Ellerbroek, Joost (author), Mühlhausen, Thorsten (author), Kügler, Dirk (author), Kern, Stefan (author), Hoekstra, J.M. (author)Involving air traffic controllers and pilots into the bird strike prevention process is considered an essential step to increase aviation and avian safety. Prior to implementing operational measures such as real-time warning systems, it is vital to evaluate their feasibility. This paper studies the efficacy of a bird strike advisory system for...journal article 2021
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Gentili, M. (author), Hoekstra, J.S.C.M. (author)Access to homeownership for young adults is becoming more and more difficult. Italy – where homeownership rates for young adults are steadily decreasing – is a case in point. In the recent past, becoming homeowner was an obvious housing pathway for Italian young adults, even from lower-middle class families. If your parents were homeowner,...journal article 2021
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Ahedo, Manuel (author), Hoekstra, J.S.C.M. (author), Extezarreta, Aitziber (author)National housing systems increasingly combine three main types of housing: the private property sector (home ownership and private rental), social and public rental (public and non-profit sectors) and cooperative (social or civil economy). The dominant private type has facilitated housing speculation, which in many countries has become a...journal article 2021
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Nurmohamed, F. Ruben H.A. (author), Van Dijk, Bruce (author), Veltman, Ewout S. (author), Hoekstra, Marrit (author), Rentenaar, Rob J. (author), Weinans, Harrie (author), Vogely, H. Charles (author), Van Der Wal, Bart C.H. (author)Introduction: Debridement, antibiotics and implant retention (DAIR) procedures are effective treatments for acute postoperative or acute hematogenous periprosthetic joint infections. However, literature reporting on the effectiveness of DAIR procedures performed after a one- or two-stage revision because of a prosthetic joint infection (PJI) ...journal article 2021
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Hoekstra, J.S.C.M. (author), Dol, C.P. (author)The ageing of European societies, the mounting pressure on pension systems, the rise of home ownership and the growth in house prices have sparked interest in housing equity release options and strategies. Much of the available literature approaches this topic through a financial lens, focusing on equity release schemes as a way to free up...journal article 2021
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Ribeiro, M.J. (author), Ellerbroek, Joost (author), Hoekstra, J.M. (author)Current investigations into urban aerial mobility, as well as the continuing growth of global air transportation, have renewed interest in conflict detection and resolution (CD&R) methods. The use of drones for applications such as package delivery, would result in traffic densities that are orders of magnitude higher than those currently...journal article 2021
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Huygen, W.J.M. (author), Sun, Junzi (author), Hoekstra, J.M. (author)Automatic Dependent Surveillance-Broadcast (ADS-B) enables aircraft to periodically broadcast their flight states such as position and velocity. Compared to classical radar surveillance, it increases update rate and accuracy. Currently, Mode S Extended Squitter is the most common implementation for ADS-B. Due to the simplicity of Mode S design,...journal article 2021
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Maas, J.B. (author), van Gent, R.N.H.W. (author), Hoekstra, J.M. (author)A detailed situation awareness of the local environment is essential for safe flight in General Aviation. When operating under Visual Flight Rules, eyesight is crucial for maintaining situation awareness and objects may be overlooked. Technical solutions such as Flarm have been sought, but they only work on a basis of co-operation: obstacles...journal article 2020
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Doole, M.M. (author), Ellerbroek, Joost (author), Hoekstra, J.M. (author)Driven by rising consumer demand, interest is growing in the application of autonomous unmanned aerial vehicles (drones) for the last-mile delivery of small express packages and fast-food meals in cities. To be realised, this would require the Very Low Level (VLL) urban airspace to be able to cope with high traffic densities of commercial...journal article 2020
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Schlathölter, Thomas (author), Mostafa, Yahia (author), Kamman, Amber (author), Dongelmans, Arnold (author), Arribard, Yann (author), Cazaux, S.M. (author), Hoekstra, Ronnie (author)Abstract: When exposed to a thermal beam of hydrogen atoms, gas-phase coronene cations C<sub>24</sub>H<sub>12</sub><sup>+</sup> can be sequentially hydrogenated. This process is accompanied by a gradual transition of the electronic structure from aromatic to aliphatic. The planar very stable coronene structure transforms into the...journal article 2020
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Sun, Junzi (author), Vû, Huy (author), Olive, Xavier (author), Hoekstra, J.M. (author)Mode S surveillance allows air traffic controllers to interrogate certain information from aircraft, such as airspeeds, turn parameters, target altitudes, and meteorological conditions. However, not all aircraft have enabled the same capabilities. Before performing any specific interrogation, the surveillance radar must acquire the transponder...journal article 2020
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Elsinga, M.G. (author), Hoekstra, J.S.C.M. (author), Sedighi, S.M.A. (author), Taebi, B. (author)A perusal of the literature on housing debates reveals that the term ‘value’ is mostly applied to express the financial value of a house and is dealt with in economic literature. However, an alternative meaning of the word ‘value’ in the housing literature can be found in research into the values underlying housing preferences, applying research...journal article 2020
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Sun, Junzi (author), Hoekstra, J.M. (author), Ellerbroek, Joost (author)In air traffic management research, aircraft performance models are often used to generate and analyze aircraft trajectories. Although a crucial part of the aircraft performance model, the aerodynamic property of aircraft is rarely available for public research purposes, as it is protected by aircraft manufacturers for commercial reasons. In...journal article 2020
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Hoekstra, J.S.C.M. (author)This paper makes a plea for a new form of international comparative housing research, in which not countries (national housing regimes) but cities or regions (local housing regimes) are the unit of analysis. Why do we need such a new comparative research approach? How can a local housing regime be conceptualised? By answering these questions,...journal article 2020
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Gawehn, M.A. (author), van Dongeren, Ap (author), de Vries, S. (author), Swinkels, Cilia (author), Hoekstra, Roderik (author), Aarninkhof, S.G.J. (author), Friedman, Joshua (author)Coastal management in the Netherlands has the aim to defend coastal zones by preventing flooding and mitigating erosion. To that end, large-scale nourishments are placed in the nearshore, which are supposed to dynamically preserve the coastal zone over a timescale of years. To assess their effectiveness, these nourishments are monitored over...journal article 2020
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Zhang, Q. (author), Hoekstra, J.S.C.M. (author)The 2014 hukou reform introduced by the Chinese central government was a turning point in China’s policies towards migration. Different from the previous hukou policies, which were largely exclusionary, the reformed policy encouraged migrants to permanently settle in their destination cities and make use of the public services available there....journal article 2020