340 research outputs found

    Event-based Vision meets Deep Learning on Steering Prediction for Self-driving Cars

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    Event cameras are bio-inspired vision sensors that naturally capture the dynamics of a scene, filtering out redundant information. This paper presents a deep neural network approach that unlocks the potential of event cameras on a challenging motion-estimation task: prediction of a vehicle's steering angle. To make the best out of this sensor-algorithm combination, we adapt state-of-the-art convolutional architectures to the output of event sensors and extensively evaluate the performance of our approach on a publicly available large scale event-camera dataset (~1000 km). We present qualitative and quantitative explanations of why event cameras allow robust steering prediction even in cases where traditional cameras fail, e.g. challenging illumination conditions and fast motion. Finally, we demonstrate the advantages of leveraging transfer learning from traditional to event-based vision, and show that our approach outperforms state-of-the-art algorithms based on standard cameras.Comment: 9 pages, 8 figures, 6 tables. Video: https://youtu.be/_r_bsjkJTH

    Characterization of a high strain composite material

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    L'Garde has designed and developed a high-strain composite material consisting of car- bon FIbers embedded in a silicone matrix. The behavior of this material is significantly different from standard composites and the paper presents special test methods to measure the properties of this material. It is found that rule of mixtures estimates are quite accurate for the longitudinal moduli in tension and bending, but less accurate for compression. The Poisson's ratio prediction is also not accurate. Regarding the strength of the composite, it is found that conservative predictions of tensile and compressive strengths can be obtained respectively from the Weibull distribution of the strength of a single fiber combined with a simple bundle theory, and the elastic fiber microbuckling stress

    Cross sections for the excitation of isovector charge-exchange resonances in 208Tl

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    The Glauber approximation for the treatment of heavy-ion scattering, has already been shown to give reliable predictions for the reaction cross section in the particular case of intermediate energy charge-exchange processes. In the present work, we couple a Glauber-type model to microscopic Random Phase Approximation calculations of the charge-exchange excitations of 208^{208}Pb. The aim is to solve the longstanding question whether the very elusive charge-exchange isovector monopole has been really identified in the past experiments, or other multipoles were prevalent in the observed spectra.Comment: text + 4 figures; accepted for publication in Phys. Rev.

    Oxide Breakdown Spot Spatial Patterns as Fingerprints for Optical Physical Unclonable Functions

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    Dielectric Breakdown (BD) of the gate oxide in a Metal-Insulator-Semiconductor (MIS) or Metal-Insulator-Metal (MIM) structure has been traditionally considered a major drawback since such event can seriously affect the electrical performance of the circuit containing the device. However, since BD is an inherently random process, when externally detectable by optical means, the phenomenon can be used to generate cryptographic keys for Physically Unclonable Functions (PUFs). This is the case discussed here. Images containing BD spot spatial distributions in MIM devices were binarized and their uniformity, uniqueness and reproducibility evaluated as fingerprints for security applications such as anti-counterfeiting purposes, secure identification and authentication of components. The obtained results are highly promising since it is demonstrated that the generated fingerprints meet all the mandatory requirements for PUFs, indicating that the proposed approach is potentially useful for this kind of applications

    Water surface height determination with a GPS wave glider: a demonstration in Loch Ness, Scotland

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    A geodetic GPS receiver has been installed on a Wave Glider, an unmanned water surface vehicle. Using kinematic precise point positioning (PPP) GPS, which operates globally without directly requiring reference stations, surface heights are measured with ~0.05-m precision. The GPS Wave Glider was tested in Loch Ness, Scotland, by measuring the gradient of the loch’s surface height. The experiment took place under mild weather, with virtually no wind setup along the loch and a wave field made mostly of ripples and wavelets. Under these conditions, the loch’s surface height gradient should be approximately equal to the geoid slope. The PPP surface height gradient and that of the Earth Gravitational Model 2008 geoid heights do indeed agree on average along the loch (0.03 m km−1). Also detected are 1) ~0.05-m-sized height changes due to daily water pumping for hydroelectricity generation and 2) high-frequency (0.25–0.5 Hz) oscillations caused by surface waves. The PPP heights compare favorably (~0.02-m standard deviation) with relative carrier phase–based GPS processing. This suggests that GPS Wave Gliders have the potential to autonomously determine centimeter-precise water surface heights globally for lake modeling, and also for applications such as ocean modeling and geoid/mean dynamic topography determination, at least for benign surface states such as those encountered during the reported experiment

    Electron transport through electrically induced nanoconstrictions in HfSiON gate stacks

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    A microscopic picture for the progressive leakage current growth in electrically stressed HfxSi1−xON/SiON gate stacks in metal-oxide-semiconductor transistors based on the physics of mesoscopic conductors is proposed. The breakdown spot is modeled as a nanoconstriction connecting two electron reservoirs. We show that after eliminating the tunnelingcurrent component that flows through the nondamaged device area, the postbreakdown conductance exhibits levels of the order of the quantum unit 2e2/h, where e is the electron charge and h the Planck's constant, as is expected for atomic-sized contacts. Similarities and differences with previous studied systems are discussed

    Modeling the breakdown spots in silicon dioxide ïŹlms as point contacts

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    Experiments and simulations are combined to demonstrate that the hard dielectric breakdown of thin SiO2 films in polycrystaline silicon/oxide/semiconductor structures leads to the formation of conduction paths with atomic-size dimensions which behave as point contacts between the silicon electrodes. Depending on the area of the breakdown spots, the conduction properties of the breakdown paths are shown to be those of a classical Sharvin point contact or of a quantum point contact

    Nanometer-scale electrical characterization of stressed ultrathin SiO2 ïŹlms using conducting atomic force microscopy

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    A conductive atomic force microscope has been used to electrically stress and to investigate the effects of degradation in the conduction properties of ultrathin (<6 nm) SiO2 films on a nanometer scale (areas of ≈100 nm2). Before oxide breakdown, switching between two states of well-defined conductivity and sudden changes of conductivity were observed, which are attributed to the capture/release of single charges in the defects generated during stress
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