483 research outputs found
Non-local Neural Networks
Both convolutional and recurrent operations are building blocks that process
one local neighborhood at a time. In this paper, we present non-local
operations as a generic family of building blocks for capturing long-range
dependencies. Inspired by the classical non-local means method in computer
vision, our non-local operation computes the response at a position as a
weighted sum of the features at all positions. This building block can be
plugged into many computer vision architectures. On the task of video
classification, even without any bells and whistles, our non-local models can
compete or outperform current competition winners on both Kinetics and Charades
datasets. In static image recognition, our non-local models improve object
detection/segmentation and pose estimation on the COCO suite of tasks. Code is
available at https://github.com/facebookresearch/video-nonlocal-net .Comment: CVPR 2018, code is available at:
https://github.com/facebookresearch/video-nonlocal-ne
YouTube AV 50K: An Annotated Corpus for Comments in Autonomous Vehicles
With one billion monthly viewers, and millions of users discussing and
sharing opinions, comments below YouTube videos are rich sources of data for
opinion mining and sentiment analysis. We introduce the YouTube AV 50K dataset,
a freely-available collections of more than 50,000 YouTube comments and
metadata below autonomous vehicle (AV)-related videos. We describe its creation
process, its content and data format, and discuss its possible usages.
Especially, we do a case study of the first self-driving car fatality to
evaluate the dataset, and show how we can use this dataset to better understand
public attitudes toward self-driving cars and public reactions to the accident.
Future developments of the dataset are also discussed.Comment: in Proceedings of the Thirteenth International Joint Symposium on
Artificial Intelligence and Natural Language Processing (iSAI-NLP 2018
Nonlinear magnetotransport shaped by Fermi surface topology and convexity in WTe2
The nature of Fermi surface defines the physical properties of conductors and
many physical phenomena can be traced to its shape. Although the recent
discovery of a current-dependent nonlinear magnetoresistance in spin-polarized
non-magnetic materials has attracted considerable attention in spintronics,
correlations between this phenomenon and the underlying fermiology remain
unexplored. Here, we report the observation of nonlinear magnetoresistance at
room temperature in a semimetal WTe2, with an interesting temperature-driven
inversion. Theoretical calculations reproduce the nonlinear transport
measurements and allow us to attribute the inversion to temperature-induced
changes in Fermi surface convexity. We also report a large anisotropy of
nonlinear magnetoresistance in WTe2, due to its low symmetry of Fermi surfaces.
The good agreement between experiments and theoretical modeling reveals the
critical role of Fermi surface topology and convexity on the nonlinear
magneto-response. These results lay a new path to explore ramifications of
distinct fermiology for nonlinear transport in condensed-matter
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