82 research outputs found
Ontology based Scene Creation for the Development of Automated Vehicles
The introduction of automated vehicles without permanent human supervision
demands a functional system description, including functional system boundaries
and a comprehensive safety analysis. These inputs to the technical development
can be identified and analyzed by a scenario-based approach. Furthermore, to
establish an economical test and release process, a large number of scenarios
must be identified to obtain meaningful test results. Experts are doing well to
identify scenarios that are difficult to handle or unlikely to happen. However,
experts are unlikely to identify all scenarios possible based on the knowledge
they have on hand. Expert knowledge modeled for computer aided processing may
help for the purpose of providing a wide range of scenarios. This contribution
reviews ontologies as knowledge-based systems in the field of automated
vehicles, and proposes a generation of traffic scenes in natural language as a
basis for a scenario creation.Comment: Accepted at the 2018 IEEE Intelligent Vehicles Symposium, 8 pages, 10
figure
Towards Efficient Hazard Identification in the Concept Phase of Driverless Vehicle Development
The complex functional structure of driverless vehicles induces a multitude
of potential malfunctions. Established approaches for a systematic hazard
identification generate individual potentially hazardous scenarios for each
identified malfunction. This leads to inefficiencies in a purely expert-based
hazard analysis process, as each of the many scenarios has to be examined
individually. In this contribution, we propose an adaptation of the strategy
for hazard identification for the development of automated vehicles. Instead of
focusing on malfunctions, we base our process on deviations from desired
vehicle behavior in selected operational scenarios analyzed in the concept
phase. By evaluating externally observable deviations from a desired behavior,
we encapsulate individual malfunctions and reduce the amount of generated
potentially hazardous scenarios. After introducing our hazard identification
strategy, we illustrate its application on one of the operational scenarios
used in the research project UNICAR.Comment: Published in 2020 IEEE Intelligent Vehicles Symposium (IV), Las
Vegas, NV, USA, October 19-November 13, 202
Functional Safety Concept Generation within the Process of Preliminary Design of Automated Driving Functions at the Example of an Unmanned Protective Vehicle
Structuring the early design phase of automotive systems is an important part of efficient and successful
development processes. Today, safety considerations (e.g., the safety life cycle of ISO 26262)
significantly affect the course of development. Preliminary designs are expressed in functional system
architectures, which are required to form safety concepts. Thus, mapping tasks and work products to a
reference process during early design stages is an important part of structuring the system development.
This contribution describes the systematic creation and notation of the functional safety concept within
the concept phase of development of an unmanned protective vehicle within the research project aFAS.
Different stages of preliminary design and dependencies between them are displayed by the work
products created and used. The full set of functional safety requirements and an excerpt of the safety
argument structure of the SAE level 4 application are presented
Kinematically complete experimental study of Compton scattering at helium atoms near the ionization threshold
Compton scattering is one of the fundamental interaction processes of light
with matter. Already upon its discovery [1] it was described as a billiard-type
collision of a photon kicking a quasi-free electron. With decreasing photon
energy, the maximum possible momentum transfer becomes so small that the
corresponding energy falls below the binding energy of the electron. Then
ionization by Compton scattering becomes an intriguing quantum phenomenon. Here
we report a kinematically complete experiment on Compton scattering at helium
atoms below that threshold. We determine the momentum correlations of the
electron, the recoiling ion, and the scattered photon in a coincidence
experiment finding that electrons are not only emitted in the direction of the
momentum transfer, but that there is a second peak of ejection to the backward
direction. This finding links Compton scattering to processes as ionization by
ultrashort optical pulses [2], electron impact ionization [3,4], ion impact
ionization [5,6], and neutron scattering [7] where similar momentum patterns
occur.Comment: 7 pages, 4 figure
Enabling time-resolved 2D spatial-coherence measurements using the Fourier-analysis method with an integrated curved-grating beam monitor
Direct 2D spatial-coherence measurements are increasingly gaining importance at synchrotron beamlines, especially due to present and future upgrades of synchrotron facilities to diffraction-limited storage rings. We present a method to determine the 2D spatial coherence of synchrotron radiation in a direct and particularly simple way by using the Fourier-analysis method in conjunction with curved gratings. Direct photon-beam monitoring provided by a curved grating circumvents the otherwise necessary separate determination of the illuminating intensity distribution required for the Fourier-analysis method. Hence, combining these two methods allows for time-resolved spatial-coherence measurements. As a consequence, spatial-coherence degradation effects caused by beamline optics vibrations, which is one of the key issues of state-of-the-art X-ray imaging and scattering beamlines, can be identified and analyzed. © 2020 Optical Society of America
- …