124 research outputs found
Quantum-trajectory analysis for charge transfer in solid materials induced by strong laser fields
We investigate the dependence of charge transfer on the intensity of driving
laser field when SiO2 crystal is irradiated by an 800 nm laser. It is
surprising that the direction of charge transfer undergoes a sudden reversal
when the driving laser intensity exceeds critical values with different carrier
envelope phases. By applying quantum-trajectory analysis, we find that the
Bloch oscillation plays an important role in charge transfer in solid. Also, we
study the interaction of strong laser with gallium nitride (GaN) that is widely
used in optoelectronics. A pump-probe scheme is applied to control the quantum
trajectories of the electrons in the conduction band. The signal of charge
transfer is controlled successfully by means of theoretically proposed
approach
Review of the Resources and Utilization of Bamboo in China
China has made a breakthrough in the development and scientific cultivation of bamboo. At present, China ranks first in bamboo research worldwide, because of numerous research units and strong technical force. This chapter focuses on the utilization of bamboo resources such as food, roofs and walls of houses, fences, and domestic and agricultural implements such as water containers, food and drink container hats, arrows, quiver, etc. A total of 861 species and infraspecific taxa belonging to 43 genera have been reported and include 707 species, 52 varieties, 98 forma, and 4 hybrids, which are naturally distributed in 21 provinces. The national bamboo forest covers 6.01 million ha, including 4.43 million ha of Moso bamboo and 1.58 million ha of other bamboo species. As the country develops and new economic activities emerge, bamboo production has shifted from harsh processing, such as bamboo basket, to finished machining, such as bamboo flooring. The bamboo industry has attracted new opportunities as a new energy source, particularly renewable energy, and may be considered a lignocellulose substrate for bioethanol production because of its environmental benefits and high annual biomass yield
Towards Large-scale Masked Face Recognition
During the COVID-19 coronavirus epidemic, almost everyone is wearing masks,
which poses a huge challenge for deep learning-based face recognition
algorithms. In this paper, we will present our \textbf{championship} solutions
in ICCV MFR WebFace260M and InsightFace unconstrained tracks. We will focus on
four challenges in large-scale masked face recognition, i.e., super-large scale
training, data noise handling, masked and non-masked face recognition accuracy
balancing, and how to design inference-friendly model architecture. We hope
that the discussion on these four aspects can guide future research towards
more robust masked face recognition systems.Comment: the top1 solution for ICCV2021-MFR challeng
KPNet: Towards Minimal Face Detector
The small receptive field and capacity of minimal neural networks limit their
performance when using them to be the backbone of detectors. In this work, we
find that the appearance feature of a generic face is discriminative enough for
a tiny and shallow neural network to verify from the background. And the
essential barriers behind us are 1) the vague definition of the face bounding
box and 2) tricky design of anchor-boxes or receptive field. Unlike most
top-down methods for joint face detection and alignment, the proposed KPNet
detects small facial keypoints instead of the whole face by in a bottom-up
manner. It first predicts the facial landmarks from a low-resolution image via
the well-designed fine-grained scale approximation and scale adaptive
soft-argmax operator. Finally, the precise face bounding boxes, no matter how
we define it, can be inferred from the keypoints. Without any complex head
architecture or meticulous network designing, the KPNet achieves
state-of-the-art accuracy on generic face detection and alignment benchmarks
with only parameters, which runs at 1000fps on GPU and is easy to
perform real-time on most modern front-end chips.Comment: AAAI 202
Teach-DETR: Better Training DETR with Teachers
In this paper, we present a novel training scheme, namely Teach-DETR, to
learn better DETR-based detectors from versatile teacher detectors. We show
that the predicted boxes from teacher detectors are effective medium to
transfer knowledge of teacher detectors, which could be either RCNN-based or
DETR-based detectors, to train a more accurate and robust DETR model. This new
training scheme can easily incorporate the predicted boxes from multiple
teacher detectors, each of which provides parallel supervisions to the student
DETR. Our strategy introduces no additional parameters and adds negligible
computational cost to the original detector during training. During inference,
Teach-DETR brings zero additional overhead and maintains the merit of requiring
no non-maximum suppression. Extensive experiments show that our method leads to
consistent improvement for various DETR-based detectors. Specifically, we
improve the state-of-the-art detector DINO with Swin-Large backbone, 4 scales
of feature maps and 36-epoch training schedule, from 57.8% to 58.9% in terms of
mean average precision on MSCOCO 2017 validation set. Code will be available at
https://github.com/LeonHLJ/Teach-DETR
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