153 research outputs found
Topology-aware MLP for Skeleton-based Action Recognition
Graph convolution networks (GCNs) have achieved remarkable performance in
skeleton-based action recognition. However, existing previous GCN-based methods
have relied excessively on elaborate human body priors and constructed complex
feature aggregation mechanisms, which limits the generalizability of networks.
To solve these problems, we propose a novel Spatial Topology Gating Unit
(STGU), which is an MLP-based variant without extra priors, to capture the
co-occurrence topology features that encode the spatial dependency across all
joints. In STGU, to model the sample-specific and completely independent
point-wise topology attention, a new gate-based feature interaction mechanism
is introduced to activate the features point-to-point by the attention map
generated from the input. Based on the STGU, in this work, we propose the first
topology-aware MLP-based model, Ta-MLP, for skeleton-based action recognition.
In comparison with existing previous methods on three large-scale datasets,
Ta-MLP achieves competitive performance. In addition, Ta-MLP reduces the
parameters by up to 62.5% with favorable results. Compared with previous
state-of-the-art (SOAT) approaches, Ta-MLP pushes the frontier of real-time
action recognition. The code will be available at
https://github.com/BUPTSJZhang/Ta-MLP.Comment: 10 pages, 9 figure
Crosstalk Impacts on Homogeneous Weakly-Coupled Multicore Fiber Based IM/DD System
We numerically discussed crosstalk impacts on homogeneous weakly-coupled
multicore fiber based intensity modulation/direct-detection (IM/DD) systems
taking into account mean crosstalk power fluctuation, walk-off between cores,
laser frequency offset, and laser linewidth.Comment: 3 pages, 11 figures
EPCFormer: Expression Prompt Collaboration Transformer for Universal Referring Video Object Segmentation
Audio-guided Video Object Segmentation (A-VOS) and Referring Video Object
Segmentation (R-VOS) are two highly-related tasks, which both aim to segment
specific objects from video sequences according to user-provided expression
prompts. However, due to the challenges in modeling representations for
different modalities, contemporary methods struggle to strike a balance between
interaction flexibility and high-precision localization and segmentation. In
this paper, we address this problem from two perspectives: the alignment
representation of audio and text and the deep interaction among audio, text,
and visual features. First, we propose a universal architecture, the Expression
Prompt Collaboration Transformer, herein EPCFormer. Next, we propose an
Expression Alignment (EA) mechanism for audio and text expressions. By
introducing contrastive learning for audio and text expressions, the proposed
EPCFormer realizes comprehension of the semantic equivalence between audio and
text expressions denoting the same objects. Then, to facilitate deep
interactions among audio, text, and video features, we introduce an
Expression-Visual Attention (EVA) mechanism. The knowledge of video object
segmentation in terms of the expression prompts can seamlessly transfer between
the two tasks by deeply exploring complementary cues between text and audio.
Experiments on well-recognized benchmarks demonstrate that our universal
EPCFormer attains state-of-the-art results on both tasks. The source code of
EPCFormer will be made publicly available at
https://github.com/lab206/EPCFormer.Comment: The source code will be made publicly available at
https://github.com/lab206/EPCForme
Galaxy-galaxy weak-lensing measurement from SDSS: II. host halo properties of galaxy groups
As the second paper of a series on studying galaxy-galaxy lensing signals
using the Sloan Digital Sky Survey Data Release 7 (SDSS DR7), we present our
measurement and modelling of the lensing signals around groups of galaxies. We
divide the groups into four halo mass bins, and measure the signals around four
different halo-center tracers: brightest central galaxy (BCG),
luminosity-weighted center, number-weighted center and X-ray peak position. For
X-ray and SDSS DR7 cross identified groups, we further split the groups into
low and high X-ray emission subsamples, both of which are assigned with two
halo-center tracers, BCGs and X-ray peak positions. The galaxy-galaxy lensing
signals show that BCGs, among the four candidates, are the best halo-center
tracers. We model the lensing signals using a combination of four
contributions: off-centered NFW host halo profile, sub-halo contribution,
stellar contribution, and projected 2-halo term. We sample the posterior of 5
parameters i.e., halo mass, concentration, off-centering distance, sub halo
mass, and fraction of subhalos via a MCMC package using the galaxy-galaxy
lensing signals. After taking into account the sampling effects (e.g. Eddington
bias), we found the best fit halo masses obtained from lensing signals are
quite consistent with those obtained in the group catalog based on an abundance
matching method, except in the lowest mass bin. Subject headings: (cosmology:)
gravitational lensing, galaxies: clusters: generalComment: 12 pages, 7 figures, submitted to Ap
Characterization of dynamic morphological changes of tin anode electrode during (de)lithiation processes using in operando synchrotron transmission X-ray microscopy
The morphological evolution of tin particles with different sizes during the first lithiation and delithiation processes has been visualized by an in operando synchrotron transmission X-ray microscope (TXM). The in operando lithium ion battery cell was operated at constant current condition during TXM imaging. Two-dimensional projection images with 40 nm resolution showing morphological evolution were obtained and analyzed. The analysis of relative area change shows that the morphology of tin particles with different sizes changed simultaneously. This phenomenon is mainly due to a negative feedback mechanism among tin particles in the battery electrode at a constant current operating condition. For irregular-shaped tin particles, the contour analysis shows that the regions with higher curvature started volume expansion first, and then the entire particle expanded almost homogeneously. This study provides insights for understanding the dynamic morphological change and the particle-particle interactions in high capacity lithium ion battery electrodes
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