15,080 research outputs found
A Fast Integrated Planning and Control Framework for Autonomous Driving via Imitation Learning
For safe and efficient planning and control in autonomous driving, we need a
driving policy which can achieve desirable driving quality in long-term horizon
with guaranteed safety and feasibility. Optimization-based approaches, such as
Model Predictive Control (MPC), can provide such optimal policies, but their
computational complexity is generally unacceptable for real-time
implementation. To address this problem, we propose a fast integrated planning
and control framework that combines learning- and optimization-based approaches
in a two-layer hierarchical structure. The first layer, defined as the "policy
layer", is established by a neural network which learns the long-term optimal
driving policy generated by MPC. The second layer, called the "execution
layer", is a short-term optimization-based controller that tracks the reference
trajecotries given by the "policy layer" with guaranteed short-term safety and
feasibility. Moreover, with efficient and highly-representative features, a
small-size neural network is sufficient in the "policy layer" to handle many
complicated driving scenarios. This renders online imitation learning with
Dataset Aggregation (DAgger) so that the performance of the "policy layer" can
be improved rapidly and continuously online. Several exampled driving scenarios
are demonstrated to verify the effectiveness and efficiency of the proposed
framework
OVSNet : Towards One-Pass Real-Time Video Object Segmentation
Video object segmentation aims at accurately segmenting the target object
regions across consecutive frames. It is technically challenging for coping
with complicated factors (e.g., shape deformations, occlusion and out of the
lens). Recent approaches have largely solved them by using backforth
re-identification and bi-directional mask propagation. However, their methods
are extremely slow and only support offline inference, which in principle
cannot be applied in real time. Motivated by this observation, we propose a
efficient detection-based paradigm for video object segmentation. We propose an
unified One-Pass Video Segmentation framework (OVS-Net) for modeling
spatial-temporal representation in a unified pipeline, which seamlessly
integrates object detection, object segmentation, and object re-identification.
The proposed framework lends itself to one-pass inference that effectively and
efficiently performs video object segmentation. Moreover, we propose a
maskguided attention module for modeling the multi-scale object boundary and
multi-level feature fusion. Experiments on the challenging DAVIS 2017
demonstrate the effectiveness of the proposed framework with comparable
performance to the state-of-the-art, and the great efficiency about 11.5 FPS
towards pioneering real-time work to our knowledge, more than 5 times faster
than other state-of-the-art methods.Comment: 10 pages, 6 figure
Bond relaxation, electronic and magnetic behavior of 2D metals structures Y on Li(110) surface
We investigated the bond, electronic and magnetic behavior of adsorption
Yttrium atoms on Lithium (110) surface using a combination of
Bond-order-length-strength(BOLS) correlation and density-functional
theory(DFT). We found that adsorption Y atoms on Li(110) surfaces form
two-dimensional (2D) geometric structures of hexagon, nonagon, solid hexagonal,
quadrangle and triangle. The consistent with the magnetic moment are
6.66{\mu}B, 5.54{\mu}B, 0.28{\mu}B, 1.04{\mu}B, 2.81{\mu}B, respectively. In
addition, this work could pave the way for design new 2D metals electronic and
magnetic properties
Optically-Nonactive Assorted Helices Array with Interchangeable Magnetic/Electric Resonance
We report here the designing of optically-nonactive metamaterial by
assembling metallic helices with different chirality. With linearly polarized
incident light, pure electric or magnetic resonance can be selectively
realized, which leads to negative permittivity or negative permeability
accordingly. Further, we show that pure electric or magnetic resonance can be
interchanged at the same frequency band by merely changing the polarization of
incident light for 90 degrees. This design demonstrates a unique approach to
construct metamaterial.Comment: 15 pages, 4 figure
Buildings as systems.
Massachusetts Institute of Technology. Dept. of Architecture. Thesis. 1966. M.Arch.Accompanying drawings held by MIT Museum.M.Arch
Synthesis of CdTe quantum dot-conjugated CC49 and their application for in vitro imaging of gastric adenocarcinoma cells
The purpose of this experiment was to investigate the visible imaging of gastric adenocarcinoma cells in vitro by targeting tumor-associated glycoprotein 72 (TAG-72) with near-infrared quantum dots (QDs). QDs with an emission wavelength of about 550 to 780 nm were conjugated to CC49 monoclonal antibodies against TAG-72, resulting in a probe named as CC49-QDs. A gastric adenocarcinoma cell line (MGC80-3) expressing high levels of TAG-72 was cultured for fluorescence imaging, and a gastric epithelial cell line (GES-1) was used for the negative control group. Transmission electron microscopy indicated that the average diameter of CC49-QDs was 0.2 nm higher compared with that of the primary QDs. Also, fluorescence spectrum analysis indicated that the CC49-QDs did not have different optical properties compared to the primary QDs. Immunohistochemical examination and in vitro fluorescence imaging of the tumors showed that the CC49-QDs probe could bind TAG-72 expressed on MGC80-3 cells
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