Publication Server of Aschaffenburg University
Not a member yet
1531 research outputs found
Sort by
Power quality—Evaluation of safe operation of observatories
No full textThe electric power supply of astronomical observatories has to manage a conflict of
interest: Observatories are situated at remote locations, they have a high consumption
of electric power while measuring electric signals as sensitively as possible.
Within the project SLOBATCO, the question did arise, to what extent observatories
have to rely on adequate power quality, for example, the perfectly sinusoidal shape
of supply voltage and current, to ensure safe operation and accurate measurement
results. International power quality standards are put in perspective with requirement
specifications for observatories. This contribution describes themotivation, the
underlying mechanisms that lead to issues, comments on the challenge in power systems
engineering, proposes the instrumentation and installation, and interprets the
first results. Experimental results clearly motivate the need for further measurement
campaigns, as power-quality-related problems are common. A summary is provided
together with an outlook and a motivation for future measurement campaigns
Trajectory Forecasts with Uncertainties of Vulnerable Road Users by Means of Neural Networks
No full textIn this article, we present an approach to forecast trajectories of vulnerable road users (VRUs) including a numerical quantification of the uncertainty of the forecast. The uncertainty estimates are modeled as normal distributions by means of neural networks. Additionally, we present a method to evaluate the reliability of the forecasted uncertainty estimates, where we utilize quantile-quantile (Q-Q) plots, a graphical method to compare two distributions widely used in statistics. The positional accuracy is evaluated using Euclidean distances, in specific we use the average Euclidean error (AEE) and the average specific AEE (ASAEE). The model is trained and tested using a large dataset of 1311 cyclist trajectories, recorded at an urban intersection in real world traffic. Using this method, we achieve a similar positional accuracy compared to our previous work, where only positions are forecasted. The method is able to produce reliable uncertainty estimates for the motion types start, stop, turn left, and turn rightand produces underconfident uncertainty estimates for the motion types waitand move straight. Since uncertainties are not underestimated, the method can be used as a basis for trajectory planing in automated vehicles
Laser-bonding of FEP/FEP interfaces for a flexiblemanufacturing process of ferroelectrets
No full textThis paper presents an optimized laser-bonding process for piezoelectric energy-harvesters based on thin fluorinated-ethylene-propylene (FEP) foils, using an ultra-short-pulse(USP) laser. Due to the minimized thermal stress in the material during bonding, achieved bypulse durations of few picoseconds, we created seams down to 40μm width without generatingholes in the 12.5μm thick FEP-foils. Using a galvanometer scanning system allowed for fastbonding-speed up to several centimeters per second, making the process also suitable for largestructures and areas. The achieved bond strength of the seams under influence of shearingstress was examined using tensile testing, which showed a sufficient strength of about 25 % of the maximum strength of an unbonded, single layer of FEP
