157 research outputs found
Enhancing vibration isolation performance by exploiting novel spring-bar mechanism
This study investigates the use of a spring-bar mechanism (SBM) in a vibration suppression system to improve its performance. The SBM, comprising bars and springs, is configured with a conventional linear spring-damper isolator unit. The dynamic response, force transmissibility, and vibration energy flow behaviour are studied to evaluate the vibration suppression performance of the integrated system. It is found that the SBM can introduce hardening, softening stiffness, or double-well potential characteristics to the system. By tuning the SBM parameters, constant negative stiffness is achieved so that the natural frequency of the overall system is reduced for enhanced low-frequency vibration isolation. It is also found that the proposed design yields a wider effective isolation range compared to the conventional spring-damper isolator and a previously proposed isolator with a negative stiffness mechanism. The frequency response relation of the force-excited system is derived using the averaging method and elliptical functions. It is also found that the system can exhibit chaotic motions, for which the associated time-averaged power is found to tend to an asymptotic value as the averaging time increases. It is shown that the time-averaged power flow variables can be used as uniform performance indices of nonlinear vibration isolators exhibiting periodic or chaotic motions. It is shown that the SBM can assist in reducing force transmission and input power, thereby expanding the frequency range of vibration attenuations
RXFOOD: Plug-in RGB-X Fusion for Object of Interest Detection
The emergence of different sensors (Near-Infrared, Depth, etc.) is a remedy
for the limited application scenarios of traditional RGB camera. The RGB-X
tasks, which rely on RGB input and another type of data input to resolve
specific problems, have become a popular research topic in multimedia. A
crucial part in two-branch RGB-X deep neural networks is how to fuse
information across modalities. Given the tremendous information inside RGB-X
networks, previous works typically apply naive fusion (e.g., average or max
fusion) or only focus on the feature fusion at the same scale(s). While in this
paper, we propose a novel method called RXFOOD for the fusion of features
across different scales within the same modality branch and from different
modality branches simultaneously in a unified attention mechanism. An Energy
Exchange Module is designed for the interaction of each feature map's energy
matrix, who reflects the inter-relationship of different positions and
different channels inside a feature map. The RXFOOD method can be easily
incorporated to any dual-branch encoder-decoder network as a plug-in module,
and help the original backbone network better focus on important positions and
channels for object of interest detection. Experimental results on RGB-NIR
salient object detection, RGB-D salient object detection, and RGBFrequency
image manipulation detection demonstrate the clear effectiveness of the
proposed RXFOOD.Comment: 10 page
Gloss Attention for Gloss-free Sign Language Translation
Most sign language translation (SLT) methods to date require the use of gloss
annotations to provide additional supervision information, however, the
acquisition of gloss is not easy. To solve this problem, we first perform an
analysis of existing models to confirm how gloss annotations make SLT easier.
We find that it can provide two aspects of information for the model, 1) it can
help the model implicitly learn the location of semantic boundaries in
continuous sign language videos, 2) it can help the model understand the sign
language video globally. We then propose \emph{gloss attention}, which enables
the model to keep its attention within video segments that have the same
semantics locally, just as gloss helps existing models do. Furthermore, we
transfer the knowledge of sentence-to-sentence similarity from the natural
language model to our gloss attention SLT network (GASLT) to help it understand
sign language videos at the sentence level. Experimental results on multiple
large-scale sign language datasets show that our proposed GASLT model
significantly outperforms existing methods. Our code is provided in
\url{https://github.com/YinAoXiong/GASLT}
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