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Hoekstra, A.T.G. (author), Twisk, D. A M (author), Hagenzieker, M.P. (author)
Research in different domains has shown that people categorize oneself and others as ingroup (“us”) and outgroup (“them”) members, resulting in group-based stereotyping and attribution errors that may adversely affect social behaviour. To determine whether such patterns also exist in road traffic, we conducted an experimental web-based survey...
journal article 2018
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Hoekstra, J.M. (author), Ellerbroek, J. (author), Sunil, E. (author), Maas, J.B. (author)
Both U-space in Europe, as well as UTM in the USA, develop concepts and tools for UAV airspace. Enabling highdensity operations is one of the goals of these studies. Past and recent studies have analysed which factors affect the capacity of a UAV airspace. An improved understanding of this can lead to control methods for capacity management. Two...
conference paper 2018
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Sun, J. (author), Vû, Huy (author), Ellerbroek, J. (author), Hoekstra, J.M. (author)
Wind and temperature data are important parameters in aircraft performance studies. The lack of accurate measurements of these parameters forces researchers to rely on numerical weather prediction models, which are often filtered for a larger area with decreased local accuracy. Aircraft, however, also transmit information related to weather...
journal article 2018
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Sun, J. (author), Ellerbroek, J. (author), Hoekstra, J.M. (author)
Aircraft mass is a crucial piece of information for studies on aircraft performance, trajectory prediction, and many other topics of aircraft traffic management. However, It is a common challenge for researchers, as well as air traffic control, to access this proprietary information. Previously, several studies have proposed methods to estimate...
journal article 2018
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Sunil, E. (author), Ellerbroek, J. (author), Hoekstra, J.M. (author)
Decentralized en-route airspace concepts have been proposed by many studies to increase airspace safety and capacity. Most of these studies, including our own forays into this domain, have used fast-time simulation experiments to explore the benefits offered by decentralization. While simulations are indispensable during the initial design phase...
conference paper 2018
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Sun, J. (author), Blom, H.A.P. (author), Ellerbroek, J. (author), Hoekstra, J.M. (author)
This paper focuses on estimating aircraft mass and thrust setting using a recursive Bayesian method called particle filtering. The method is based on a nonlinear state-space system derived from aircraft point-mass performance models. Using solely ADS-B and Mode-S data, flight states such as position, velocity, and wind speed are collected and...
conference paper 2018
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Metz, I.C. (author), Muhlhausen, Thorsten (author), Ellerbroek, J. (author), Kügler, Dirk (author), van Gasteren, Hans (author), Kraemer, Jan (author), Hoekstra, J.M. (author)
Annually, thousands of birds collide with aircraft. The impact usually has lethal
consequences for the bird, the involved aircraft can experience severe damage. The highest bird strike risk occurs at low altitudes. Therefore, aircraft within the airport area as well as the adjacent approach and departure corridors are especially vulnerable...
journal article 2018
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Sun, J. (author), Hoekstra, J.M. (author), Ellerbroek, J. (author)
The aerodynamic properties of an aircraft determine a crucial part of the aircraft performance model. Deriving accurate aerodynamic coefficients requires detailed knowledge of the aircraft’s design. These designs and parameters are well protected by aircraft manufacturers. They rarely can be used in public research. Very detailed aerodynamic...
conference paper 2018
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Rudnyk, I. (author), Ellerbroek, J. (author), Hoekstra, J.M. (author)
conference paper 2018
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Rudnyk, I. (author), Ellerbroek, J. (author), Hoekstra, J.M. (author)
conference paper 2018
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Sunil, E. (author), Ellerbroek, J. (author), Hoekstra, J.M. (author)
This paper presents a semi-empirical method to determine the maximum theoretical capacity of decentralized airspace concepts. The method considered here, named Capacity Assessment Method for Decentralized ATC (CAMDA), formalizes an earlier approach described in literature, extends it for threedimensional airspace, and also improves the accuracy...
conference paper 2018
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Ellerbroek, J. (author), Inaad, Mazin (author), Hoekstra, J.M. (author)
This paper presents an analysis of the potential fuel and emission benefits of implementing Continuous Descent Operations at Schiphol International Airport, from cruise altitude to the final approach fix, for a large scope of aircraft types. Using historical data from on-board sources and ADS-B, fuel-optimal continuous descents are simulated...
conference paper 2018
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Metz, I.C. (author), Muhlhausen, Thorsten (author), Ellerbroek, J. (author), Hoekstra, J.M. (author)
Bird strikes have the potential to cause severe damage to aircraft. Therefore, measures to reduce the risk of bird strikes are performed at airports. However, this risk is not limited to the airport but is increased in the arrival and departure corridors as well. Consequently, a significant amount of bird strikes occurs outside the direct...
abstract 2018
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Hoekstra, M. (author)
Currently wastewater treatment plants (WWTP) consume a lot of energy and surface area. While the incoming water contains chemical energy (BOD) and reusable resources which are not effectively utilized. The ideal is to develop a treatment scheme which allows for the efficient removal of pollutants while minimizing the energy input and maximizing...
doctoral thesis 2017
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Hoekstra, M. (author), de Weerd, F.A. (author), Kleerebezem, R. (author), van Loosdrecht, Mark C.M. (author)
The implementation of autotrophic nitrogen removal in the mainstream of a municipal wastewater treatment plant is currently pursued. Among the crucial unknown factors are the kinetic properties of anaerobic ammonium oxidising (anammox) bacteria at low temperatures. In this study we investigated the adaptation of a fast-growing anammox culture...
journal article 2017
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Sunil, E. (author), Ellerbroek, J. (author), Hoekstra, J.M. (author), Arntzen, M. (author)
The work that is presented in this paper is part of an ongoing study on the relationship between airspace structure and capacity. The present paper investigates the degree of structuring needed to maximize capacity for decentralized en-routeairspace. To this end, four decentralized en-route airspace concepts,...
journal article 2017
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Sunil, E. (author), Ellerbroek, J. (author), Hoekstra, J.M. (author), Maas, J.B. (author)
In the context of decentralized separation, airspace stability pertains to the propagation of con?ict chain reactions as a result of tactical con?ict resolution maneuvers. This notion of airspace stability has been used in previous literature to develop a semi-empirical method for determining the capacity of a decentralized direct-routing...
conference paper 2017
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Sunil, E. (author), Ellerbroek, J. (author), Hoekstra, J.M. (author), Maas, J.B. (author)
Previous research relating airspace structure and ca-pacity has shown that a decentralized layered airspace concept, in which each altitude band limited horizontal travel to within a prede?ned heading range, improved safety when compared to unstructured airspace. However, the extent of the safety bene?ts of such layered airspace designs were not...
conference paper 2017
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Ellerbroek, J. (author), Hoekstra, J.M. (author), Westerveld, E (author)
The occurrence of pop-up flights negatively affects the (extended) arrival manager. This issue is known already for a long time by operational experts, but the extent thereof has now been assessed during experiments. An arrival manager research model was developed and integrated in BlueSky, an open-source air traffic management simulator. Fast...
conference paper 2017
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Jansen, S.J.T. (author), Hoekstra, J.S.C.M. (author), Boumeester, H.J.F.M. (author)
The extraction of natural gas in the north of The Netherlands has led to soil subsidence and the occurrence of earthquakes. Residents worry about the safety of their families and the saleability of their dwelling and might want to move. The goal is to examine whether the earthquakes are related to the intention to move. A survey among...
journal article 2017
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