4,583 research outputs found
Traffic-Aware Autonomous Driving with Differentiable Traffic Simulation
While there have been advancements in autonomous driving control and traffic
simulation, there have been little to no works exploring the unification of
both with deep learning. Works in both areas seem to focus on entirely
different exclusive problems, yet traffic and driving have inherent semantic
relations in the real world. In this paper, we present a generalizable
distillation-style method for traffic-informed imitation learning that directly
optimizes a autonomous driving policy for the overall benefit of faster traffic
flow and lower energy consumption. We capitalize on improving the arbitrarily
defined supervision of speed control in imitation learning systems, as most
driving research focus on perception and steering. Moreover, our method
addresses the lack of co-simulation between traffic and driving simulators and
lays groundwork for directly involving traffic simulation with autonomous
driving in future work. Our results show that, with information from traffic
simulation involved in supervision of imitation learning methods, an autonomous
vehicle can learn how to accelerate in a fashion that is beneficial for traffic
flow and overall energy consumption for all nearby vehicles
Generating energetic electron generation through staged-acceleration in the two-plasmon-decay instability in inertial confinement fusion
A new hot-electron generation mechanism in two-plasmon-decay instabilities is described based on a series of 2D, long-term ( 10 ps) particle-in-cell and fluid simulations under parameters relevant to inertial confinement fusion. The simulations show that significant laser absorption and hot-electron generation occur in the nonlinear stage. The hot electrons are stage accelerated from the low-density region to the high-density region. New modes with small phase velocities develop in the low-density region in the nonlinear stage and form the first stage for electron acceleration. Electron-ion collisions are shown to significantly reduce the efficiency of this acceleration mechanis
Information-Theoretic Measure of Genuine Multi-Qubit Entanglement
We consider pure quantum states of N qubits and study the genuine N-qubit
entanglement that is shared among all the N qubits. We introduce an
information-theoretic measure of genuine N-qubit entanglement based on
bipartite partitions. When N is an even number, this measure is presented in a
simple formula, which depends only on the purities of the partially reduced
density matrices. It can be easily computed theoretically and measured
experimentally. When N is an odd number, the measure can also be obtained in
principle.Comment: 5 pages, 2 figure
Harmonic oscillations and their switching in elliptical optical waveguide arrays
We have studied harmonic oscillations in an elliptical optical waveguide
array in which the coupling between neighboring waveguides is varied in accord
with a Kac matrix so that the propagation constant eigenvalues can take equally
spaced values. As a result, long-living Bloch oscillation (BO) and dipole
oscillation (DO) are obtained when a linear gradient in the propagation
constant is applied. Moreover, we achieve a switching from DO to BO or vice
versa by ramping up the gradient profile. The various optical oscillations as
well as their switching are investigated by field evolution analysis and
confirmed by Hamiltonian optics. The equally spaced eigenvalues in the
propagation constant allow viable applications in transmitting images,
switching and routing of optical signals.Comment: 14 pages, 5 figure
Engineering Metallic Nanocavity Radiation for Efficient Uni-/Bi-directional Coupling into Integrated Waveguide
We propose a new, simple way to engineer the radiation patterns of subwavelength-scale metallic semiconductor cavities for coupling light from a nanoscale metal cavity into integrated waveguides uni-/bi-directionally with efficiency up to ~90%
The Pseudomonas syringae type III-secreted protein HopPtoD2 possesses protein tyrosine phosphatase activity and suppresses programmed cell death in plants
The bacterial plant pathogen Pseudomonas syringae possesses a type III protein secretion system that delivers many virulence proteins into plant cells. A subset of these proteins (called Avr proteins) is recognized by the plant’s innate immune system and triggers defences. One defence-associated response is the hypersensitive response (HR), a programmed cell death (PCD) of plant tissue. We have previously identified HopPtoD2 as a type III secreted protein from P. s. pv. tomato DC3000. Sequence analysis revealed that an N-terminal domain shared homology with Avr- PphD and a C-terminal domain was similar to protein tyrosine phosphatases (PTPs). We demonstrated that purified HopPtoD2 possessed PTP activity and this activity required a conserved catalytic Cys residue (Cys 378 ). Interestingly, HopPtoD2 was capable of suppressing the HR elicited by an avirulent P. syringae strain on Nicotiana benthamiana . HopPtoD2 derivatives that lacked Cys 378 no longer suppressed the HR indicating that HR suppression required PTP activity. A constitutively active MAPK kinase, called NtMEK2 DD , is capable of eliciting an HR-like cell death when transiently expressed in tobacco. When NtMEK2 DD and HopPtoD2 were co-delivered into plant cells, the HR was suppressed indicating that HopPtoD2 acts downstream of NtMEK2 DD . DC3000 hopPtoD2 mutants were slightly reduced in their ability to multiply in planta and displayed an enhanced ability to elicit an HR. The identification of HopPtoD2 as a PTP and a PCD suppressor suggests that the inactivation of MAPK pathways is a virulence strategy utilized by bacterial plant pathogens
Engineering of metal-clad optical nanocavity to optimize coupling with integrated waveguides
We propose a cladding engineering method that flexibly modifies the radiation patterns and rates of metal-clad nanoscale optical cavity. Optimally adjusting the cladding symmetry of the metal-clad nanoscale optical cavity modifies the modal symmetry and produces highly directional radiation that leads to 90% coupling efficiency into an integrated waveguide. In addition, the radiation rate of the cavity mode can be matched to its absorption rate by adjusting the thickness of the bottom-cladding layer. This approach optimizes the energy-flow rate from the waveguide and maximizes the energy confined inside the nanoscale optical cavity
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