293 research outputs found
Global tide simulations with ICON-O: testing the model performance on highly irregular meshes
The global tide is simulated with the global ocean general circulation model ICON-O using a newly developed tidal module, which computes the full tidal potential. The simulated coastal M2 amplitudes, derived by a discrete Fourier transformation of the output sea level time series, are compared with the according values derived from satellite altimetry (TPXO-8 atlas). The experiments are repeated with four uniform and sixteen irregular triangular grids. The results show that the quality of the coastal tide simulation depends primarily on the coastal resolution and that the ocean interior can be resolved up to twenty times lower without causing considerable reductions in quality. The mesh transition zones between areas of different resolutions are formed by cell bisection and subsequent local spring optimisation tolerating a triangular cell’s maximum angle up to 84°. Numerical problems with these high-grade non-equiangular cells were not encountered. The results emphasise the numerical feasibility and potential efficiency of highly irregular computational meshes used by ICON-O. © 2020, The Author(s)
MAVERIC: A Data-Driven Approach to Personalized Autonomous Driving
Personalization of autonomous vehicles (AV) may significantly increase trust,
use, and acceptance. In particular, we hypothesize that the similarity of an
AV's driving style compared to the end-user's driving style will have a major
impact on end-user's willingness to use the AV. To investigate the impact of
driving style on user acceptance, we 1) develop a data-driven approach to
personalize driving style and 2) demonstrate that personalization significantly
impacts attitudes towards AVs. Our approach learns a high-level model that
tunes low-level controllers to ensure safe and personalized control of the AV.
The key to our approach is learning an informative, personalized embedding that
represents a user's driving style. Our framework is capable of calibrating the
level of aggression so as to optimize driving style based upon driver
preference. Across two human subject studies (n = 54), we first demonstrate our
approach mimics the driving styles of end-users and can tune attributes of
style (e.g., aggressiveness). Second, we investigate the factors (e.g., trust,
personality etc.) that impact homophily, i.e. an individual's preference for a
driving style similar to their own. We find that our approach generates driving
styles consistent with end-user styles (p<.001) and participants rate our
approach as more similar to their level of aggressiveness (p=.002). We find
that personality (p<.001), perceived similarity (p<.001), and high-velocity
driving style (p=.0031) significantly modulate the effect of homophily
Compound flood events: analysing the joint occurrence of extreme river discharge events and storm surges in northern and central Europe
The simultaneous occurrence of extreme events gained more and more attention from scientific research in the last couple of years.
Compared to the occurrence of single extreme events, co-occurring or compound extremes may substantially increase risks.
To adequately address such risks, improving our understanding of compound flood events in Europe is necessary and requires reliable estimates of their probability of occurrence together with potential future changes.
In this study compound flood events in northern and central Europe were studied using a Monte Carlo-based approach that avoids the use of copulas.
Second, we investigate if the number of observed compound extreme events is within the expected range of 2Â standard deviations of randomly occurring compound events. This includes variations of several parameters to test the stability of the identified patterns. Finally, we analyse if the observed compound extreme events had a common large-scale meteorological driver.
The results of our investigation show that rivers along the west-facing coasts of Europe experienced a
higher amount of compound flood events than expected by pure chance.
In these regions, the vast majority of the observed compound flood events seem to be related to the cyclonic westerly general weather pattern (Großwetterlage).</p
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