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Odijk, D. (author), Verhagen, S. (author), Teunissen, P.J.G. (author)The goal of Network RTK is to provide users with precise ionospheric corrections in order to conduct fast GPS ambiguity resolution and to get cm-level positioning results over medium-distance baselines. In this paper it is shown that a Network RTK user should apply the ratio test with fixed failure rate, having a threshold value that depends on...conference paper 2009
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Verhagen, S. (author), Teunissen, P.J.G. (author), Odijk, D. (author)The coming decade will bring a proliferation of Global Navigation Satellite Systems (GNSSs) that are likely to enable a much wider range of demanding applications compared to the current GPS-only situation. One such important area of application is single-frequency real-time kinematic (RTK) positioning. Presently, however, such systems lack real...conference paper 2009
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Verhagen, S. (author), Grejner-Brzezinska, D. (author), Retscher, G. (author), Santos, M. (author), Ding, X. (author), Gao, Y. (author), Jin, S. (author)This contribution focuses on geodetic sensor systems and sensor networks for positioning and applications. The key problems in this area will be addressed together with an overview of applications. Global Navigation Satellite Systems (GNSS) and other geodetic techniques play a central role in many applications like engineering, mapping and...conference paper 2009
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Giorgi, G. (author), Teunissen, P.J.G. (author), Verhagen, S. (author), Buist, P.J. (author)Integer ambiguity resolution is the key to obtain very accurate positioning solutions out of the GNSS observations. The Integer Least Squares (ILS) principle, a derivation of the least-squares principle applied to a linear system of equations in which some of the unknowns are subject to an integer constraint,was demonstrated to be optimal among...conference paper 2009
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Verhagen, H.J. (author)A new construction method of Polyurethane (PUR)-bonded revetments has been tested successfully as stable breakwater constructions on various locations in Germany (“Hamburg Hallig”, “Holm Gröde”), as dike revetment in the Netherlands (breakwater revetment in Zuidbout and Petten), as shoreline protection in France (canal embankment near Le Havre),...conference paper 2009
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Bosman, G. (author), Van der Meer, J.W. (author), Hoffmans, G. (author), Schüttrumpf, H. (author), Verhagen, H.J. (author)Recently, formulae have been derived for maximum flow depths and velocities on the crest and inner slope of dikes or levees at wave overtopping. Two independent physical model test programs in different wave flumes showed, however, a large difference in the results. The present paper clarifies this discrepancy and shows that the empirical...conference paper 2008
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De Rover, R. (author), Verhagen, H.J. (author), Van den Berge, A. (author), Reedijk, B. (author)The effect of single layer interlocking armour unit breakage on the hydraulic armour layer stability and potential damage progression is addressed in this paper. A 2-dimensional scale model of a rubble mound breakwater with an armour layer consisting of Xbloc armour units was tested. The residual armour layer stability with broken units was...conference paper 2008
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Viet, N.D. (author), Verhagen, H.J. (author), Van Gelder, P.H.A.J.M. (author), Vrijling, J.K. (author)In 2006 a Vietnamese Engineering Consultancy Company carried out a design study of a Naval Base at the location of the South of Doson Peninsula in Vietnam. A deterministic approach applied to the conceptual design of the breakwater system of the Naval Base resulted in a cross-section with a big armour layer and a rather low crest level. This...conference paper 2008
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Tuan, T.Q. (author), Verhagen, H.J. (author)The present paper is concerned with the processes of coastal barrier breaching with focus on the breach initiation induced by high activity of tropical cyclones in the northern and central coast of Vietnam. The breach initiation by the response of coastal barriers during storm surges can also be a common practice encountered in many coasts...conference paper 2008
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Viet, N.D. (author), Verhagen, H.J. (author), Van Gelder, P.H.A.J.M. (author), Vrijling, J.K. (author)An appropriate assignment of probabilities of failure to subsystems and components in a structural system can bring a minimum of costs and risk. In this paper, a method for economic optimisation of rubble mound breakwaters using pre-assigned probabilities of failure is presented. Application to a design case shows that the proposed method is...conference paper 2008
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Lam, N.T. (author), Stive, M.J.F. (author), Verhagen, H.J. (author), Wang, Z.B. (author)Morphodynamics of a tidal inlet system on a micro-tidal coast in a tropical monsoon influenced region is modelled and discussed. Influences of river flow and wave climate on the inlet morphology are investigated with the aid of process-based state-of-the-art numerical models. Seasonal and episodic behaviour of the inlet system under the...conference paper 2008
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Hoan, N.T. (author), Booij, R. (author), Hofland, B. (author), Stive, M.J.F. (author), Verhagen, H.J. (author)The current research is aimed at evaluating the applicability of a numerical flow model to predict bed damage. First, an experimental study was carried out to get more inside into the relation between flow forces acting on a bed and the bed response (damage). The experiments were then used as the basis for the evaluation. Second, the flow was...conference paper 2008
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Verhagen, H.J. (author), Jaspers Focks, D.J. (author), Algera, A. (author), Vu, M.A. (author)Vetiver grass is a sustainable and innovative solution for the protection of banks. It is shown that Vetiver grass is able to establish a full-stop of bank erosion caused by rapid drawdown. Therefore it provides us with strong indications that it is highly suitable as an anti-erosion measure. A combination of cohesive soil and Vetiver grass...conference paper 2008
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Verhagen, H.J. (author), Van Vledder, G.P. (author), Eslami Arab, S. (author)Modern design formula for coastal structures (like rock stability formula and overtopping formula use wave parameters (H2% and Tm-1,0) which are not readily available from standard boundary condition wave data. For transforming values like Hs and Tp to the parameters used in the new formulas, often-fixed conversion factors are used. However,...conference paper 2008
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Lam, N.T. (author), Stive, M.J.F. (author), Verhagen, H.J. (author), Wang, Z.B. (author)Morphodynamics of a tidal inlet system on a micro-tidal coast in a tropical monsoon influenced region is modelled and discussed. Effects of tides, waves, river flows and system configuration on the inlet morphologies are investigated with the aid of process-based state-of-the-art numerical models. Seasonal and episodic behaviour of the inlet...conference paper 2007
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Hoan, N.T. (author), Booij, R. (author), Stive, M.J.F. (author), Verhagen, H.J. (author)The velocity and turbulence distributions of decelerating open-channel flow in a gradual expansion were measured using LDV equipment. The results show that the logarithmic law can describe the mean velocity in the bottom region well while the Coles’ law can be applied to the outer region. The shear velocity can be determined both by the...conference paper 2007
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Lam, N.T. (author), Stive, M.J.F. (author), Verhagen, H.J. (author), Wang, Z.B. (author)Morphodynamics of a tidal inlet system on a micro-tidal coast in a tropical monsoon influenced region is modeled and discussed. Effects of tides, waves, river flows and system configuration on the inlet morphologies are investigated with the aid of process-based state-of-the-art numerical models. Seasonal and episodic behavior of the inlet...conference paper 2007
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Louwersheimer, W.F. (author), Verhagen, H.J. (author), Olthof, J. (author)During the construction of the first Dutch offshore wind farm prototype measurements were performed. These measurements were aimed to monitor the behaviour of the granular filter layer of the scour protection around the mono-piles upon which the wind turbines are founded. These measurements were compared to scale model test results and...conference paper 2007
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Heineke, D. (author), Verhagen, H.J. (author)To assess the hydraulic performance of coastal structures - viz. wave run-up, overtopping and reflection - and to evaluate the stability of the armour layers, use is made of the dimensionless surf similarity parameter, as introduced by Battjes (1974). The front side slope of the structure and the wave steepness are combined in this parameter,...conference paper 2007
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Hoan, N.T. (author), Booij, R. (author), Hofland, B. (author), Stive, M.J.F. (author), Verhagen, H.J. (author)The current research is aimed at finding a proper relation between flow forces acting on the bed and the bed response. To this end, experiments were carried out in which both the bed response (quantified by a dimensionless entrainment rate) and the flow field (velocity and turbulence intensity distributions) are measured. The three available...conference paper 2007