3,607 research outputs found
Quality-of-service driven power and rate adaptation for multichannel communications over wireless links
Weakly Supervised Semantic Segmentation by Knowledge Graph Inference
Currently, existing efforts in Weakly Supervised Semantic Segmentation (WSSS)
based on Convolutional Neural Networks (CNNs) have predominantly focused on
enhancing the multi-label classification network stage, with limited attention
given to the equally important downstream segmentation network. Furthermore,
CNN-based local convolutions lack the ability to model the extensive
inter-category dependencies. Therefore, this paper introduces a graph
reasoning-based approach to enhance WSSS. The aim is to improve WSSS
holistically by simultaneously enhancing both the multi-label classification
and segmentation network stages. In the multi-label classification network
segment, external knowledge is integrated, coupled with GCNs, to globally
reason about inter-class dependencies. This encourages the network to uncover
features in non-salient regions of images, thereby refining the completeness of
generated pseudo-labels. In the segmentation network segment, the proposed
Graph Reasoning Mapping (GRM) module is employed to leverage knowledge obtained
from textual databases, facilitating contextual reasoning for class
representation within image regions. This GRM module enhances feature
representation in high-level semantics of the segmentation network's local
convolutions, while dynamically learning semantic coherence for individual
samples. Using solely image-level supervision, we have achieved
state-of-the-art performance in WSSS on the PASCAL VOC 2012 and MS-COCO
datasets. Extensive experimentation on both the multi-label classification and
segmentation network stages underscores the effectiveness of the proposed graph
reasoning approach for advancing WSSS
Scalar induced gravitational waves in symmetric teleparallel gravity with a parity-violating term
Gravitational waves (GWs) are useful to test gravitational theories and to
probe the physics in the early universe. In this paper, we investigate the
scalar induced gravitational waves (SIGWs) in symmetric teleparallel gravity
with a parity-violating term. The presence of the parity-violating term leads
to the velocity birefringence effect of the SIGWs. However, after taking into
account the observational constraints on the speed of GWs, the contribution
from the parity-violating term to SIGWs is negligible. Nevertheless, the
contribution to SIGWs from the perturbations of the connection can be
significant, and results in a multipeak structure in the energy density of
SIGWs. This feature makes the symmetric teleparallel gravity distinguishable
from the general relativity.Comment: 32 pages,2 figure
Scalar induced gravitational waves from Chern-Simons gravity during inflation era
We investigate the scalar induced gravitational waves (SIGWs) in the
Chern-Simons (CS) gravity with a dynamical scalar field during slow roll
inflation. Due to the parity violation in the CS term, the SIGWs are generally
polarized, which are effectively characterized by the degree of circular
polarization. We derive the semianalytic expression to evaluate the power
spectra and the degree of circular polarization of the SIGWs, which receive
contributions from the general relativity and the parity-violating term,
respectively. We find that the correction from the parity-violating CS term is
negligible on large scales, which means that the degree of circular
polarization of SIGWs is very small.Comment: 23 pages, references added, and a new discussion about a linear
coupling function added. Version to be published in JCA
Angular Momentum of a Brane-world Model
In this paper we discuss the properties of the general covariant angular
momentum of a five-dimensional brane-world model. Through calculating the total
angular momentum of this model, we are able to analyze the properties of the
total angular momentum in the inflationary RS model. We show that the
space-like components of the total angular momentum of are all zero while the
others are non-zero, which agrees with the results from ordinary RS model.Comment: 8 pages; accepted by Chinese Physics
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