869 research outputs found
Refining Obstacle Perception Safety Zones via Maneuver-Based Decomposition
A critical task for developing safe autonomous driving stacks is to determine
whether an obstacle is safety-critical, i.e., poses an imminent threat to the
autonomous vehicle. Our previous work showed that Hamilton Jacobi reachability
theory can be applied to compute interaction-dynamics-aware perception safety
zones that better inform an ego vehicle's perception module which obstacles are
considered safety-critical. For completeness, these zones are typically larger
than absolutely necessary, forcing the perception module to pay attention to a
larger collection of objects for the sake of conservatism. As an improvement,
we propose a maneuver-based decomposition of our safety zones that leverages
information about the ego maneuver to reduce the zone volume. In particular, we
propose a "temporal convolution" operation that produces safety zones for
specific ego maneuvers, thus limiting the ego's behavior to reduce the size of
the safety zones. We show with numerical experiments that maneuver-based zones
are significantly smaller (up to 76% size reduction) than the baseline while
maintaining completeness.Comment: * indicates equal contribution. Accepted into the IEEE Intelligent
Vehicles Symposium 202
Transport equations for the inflationary trispectrum
We use transport techniques to calculate the trispectrum produced in
multiple-field inflationary models with canonical kinetic terms. Our method
allows the time evolution of the local trispectrum parameters, tauNL and gNL,
to be tracked throughout the inflationary phase. We illustrate our approach
using examples. We give a simplified method to calculate the superhorizon part
of the relation between field fluctuations on spatially flat hypersurfaces and
the curvature perturbation on uniform density slices, and obtain its
third-order part for the first time. We clarify how the 'backwards' formalism
of Yokoyama et al. relates to our analysis and other recent work. We supply
explicit formulae which enable each inflationary observable to be computed in
any canonical model of interest, using a suitable first-order ODE solver.Comment: 24 pages, plus references and appendix. v2: matches version published
in JCAP; typo fixed in Eq. (54
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