123 research outputs found
Hierarchical Disentanglement-Alignment Network for Robust SAR Vehicle Recognition
Vehicle recognition is a fundamental problem in SAR image interpretation.
However, robustly recognizing vehicle targets is a challenging task in SAR due
to the large intraclass variations and small interclass variations.
Additionally, the lack of large datasets further complicates the task. Inspired
by the analysis of target signature variations and deep learning
explainability, this paper proposes a novel domain alignment framework named
the Hierarchical Disentanglement-Alignment Network (HDANet) to achieve
robustness under various operating conditions. Concisely, HDANet integrates
feature disentanglement and alignment into a unified framework with three
modules: domain data generation, multitask-assisted mask disentanglement, and
domain alignment of target features. The first module generates diverse data
for alignment, and three simple but effective data augmentation methods are
designed to simulate target signature variations. The second module
disentangles the target features from background clutter using the
multitask-assisted mask to prevent clutter from interfering with subsequent
alignment. The third module employs a contrastive loss for domain alignment to
extract robust target features from generated diverse data and disentangled
features. Lastly, the proposed method demonstrates impressive robustness across
nine operating conditions in the MSTAR dataset, and extensive qualitative and
quantitative analyses validate the effectiveness of our framework
Boosting Convolutional Neural Networks with Middle Spectrum Grouped Convolution
This paper proposes a novel module called middle spectrum grouped convolution
(MSGC) for efficient deep convolutional neural networks (DCNNs) with the
mechanism of grouped convolution. It explores the broad "middle spectrum" area
between channel pruning and conventional grouped convolution. Compared with
channel pruning, MSGC can retain most of the information from the input feature
maps due to the group mechanism; compared with grouped convolution, MSGC
benefits from the learnability, the core of channel pruning, for constructing
its group topology, leading to better channel division. The middle spectrum
area is unfolded along four dimensions: group-wise, layer-wise, sample-wise,
and attention-wise, making it possible to reveal more powerful and
interpretable structures. As a result, the proposed module acts as a booster
that can reduce the computational cost of the host backbones for general image
recognition with even improved predictive accuracy. For example, in the
experiments on ImageNet dataset for image classification, MSGC can reduce the
multiply-accumulates (MACs) of ResNet-18 and ResNet-50 by half but still
increase the Top-1 accuracy by more than 1%. With 35% reduction of MACs, MSGC
can also increase the Top-1 accuracy of the MobileNetV2 backbone. Results on MS
COCO dataset for object detection show similar observations. Our code and
trained models are available at https://github.com/hellozhuo/msgc.Comment: 13 pages, 11 figures, submitted to IEEEE Transactions on xx
Deep Intellectual Property: A Survey
With the widespread application in industrial manufacturing and commercial
services, well-trained deep neural networks (DNNs) are becoming increasingly
valuable and crucial assets due to the tremendous training cost and excellent
generalization performance. These trained models can be utilized by users
without much expert knowledge benefiting from the emerging ''Machine Learning
as a Service'' (MLaaS) paradigm. However, this paradigm also exposes the
expensive models to various potential threats like model stealing and abuse. As
an urgent requirement to defend against these threats, Deep Intellectual
Property (DeepIP), to protect private training data, painstakingly-tuned
hyperparameters, or costly learned model weights, has been the consensus of
both industry and academia. To this end, numerous approaches have been proposed
to achieve this goal in recent years, especially to prevent or discover model
stealing and unauthorized redistribution. Given this period of rapid evolution,
the goal of this paper is to provide a comprehensive survey of the recent
achievements in this field. More than 190 research contributions are included
in this survey, covering many aspects of Deep IP Protection:
challenges/threats, invasive solutions (watermarking), non-invasive solutions
(fingerprinting), evaluation metrics, and performance. We finish the survey by
identifying promising directions for future research.Comment: 38 pages, 12 figure
Learning Audio-Visual Source Localization via False Negative Aware Contrastive Learning
Self-supervised audio-visual source localization aims to locate sound-source
objects in video frames without extra annotations. Recent methods often
approach this goal with the help of contrastive learning, which assumes only
the audio and visual contents from the same video are positive samples for each
other. However, this assumption would suffer from false negative samples in
real-world training. For example, for an audio sample, treating the frames from
the same audio class as negative samples may mislead the model and therefore
harm the learned representations e.g., the audio of a siren wailing may
reasonably correspond to the ambulances in multiple images). Based on this
observation, we propose a new learning strategy named False Negative Aware
Contrastive (FNAC) to mitigate the problem of misleading the training with such
false negative samples. Specifically, we utilize the intra-modal similarities
to identify potentially similar samples and construct corresponding adjacency
matrices to guide contrastive learning. Further, we propose to strengthen the
role of true negative samples by explicitly leveraging the visual features of
sound sources to facilitate the differentiation of authentic sounding source
regions. FNAC achieves state-of-the-art performances on Flickr-SoundNet,
VGG-Sound, and AVSBench, which demonstrates the effectiveness of our method in
mitigating the false negative issue. The code is available at
\url{https://github.com/OpenNLPLab/FNAC_AVL}.Comment: CVPR202
Chaperone Spy Protects Outer Membrane Proteins from Folding Stress via Dynamic Complex Formation
Gram-negative bacteria have a multicomponent and constitutively active periplasmic chaperone system to ensure the quality control of their outer membrane proteins (OMPs). Recently, OMPs have been identified as a new class of vulnerable targets for antibiotic development, and therefore a comprehensive understanding of OMP quality control network components will be critical for discovering antimicrobials. Here, we demonstrate that the periplasmic chaperone Spy protects certain OMPs against protein-unfolding stress and can functionally compensate for other periplasmic chaperones, namely Skp and FkpA, in the Escherichia coli K-12 MG1655 strain. After extensive; in vivo; genetic experiments for functional characterization of Spy, we use nuclear magnetic resonance and circular dichroism spectroscopy to elucidate the mechanism by which Spy binds and folds two different OMPs. Along with holding OMP substrates in a dynamic conformational ensemble, Spy binding enables OmpX to form a partially folded β-strand secondary structure. The bound OMP experiences temperature-dependent conformational exchange within the chaperone, pointing to a multitude of local dynamics. Our findings thus deepen the understanding of functional compensation among periplasmic chaperones during OMP biogenesis and will promote the development of innovative antimicrobials against pathogenic Gram-negative bacteria.; IMPORTANCE; Outer membrane proteins (OMPs) play critical roles in bacterial pathogenicity and provide a new niche for antibiotic development. A comprehensive understanding of the OMP quality control network will strongly impact antimicrobial discovery. Here, we systematically demonstrate that the periplasmic chaperone Spy has a role in maintaining the homeostasis of certain OMPs. Remarkably, Spy utilizes a unique chaperone mechanism to bind OmpX and allows it to form a partially folded β-strand secondary structure in a dynamic exchange of conformations. This mechanism differs from that of other E. coli periplasmic chaperones such as Skp and SurA, both of which maintain OMPs in disordered conformations. Our study thus deepens the understanding of the complex OMP quality control system and highlights the differences in the mechanisms of ATP-independent chaperones
Genetic Engineering of the Biosynthesis of Glycine Betaine Modulates Phosphate Homeostasis by Regulating Phosphate Acquisition in Tomato
Glycine betaine (GB), as a putative compatible substance, protects plants against the damaging effects of abiotic stresses. Phosphorus deficiency is one type of abiotic stress that is detrimental to plant growth. Maintenance of phosphate (Pi) homeostasis is crucial. This study demonstrates GB-regulated phosphate homeostasis in the tomato (Solanum lycopersicum cv. ‘Moneymaker’) transformed with the choline oxidase gene codA from Arthrobacter globiformis. The codA-transgenic lines displayed more resistance to low-phosphate stress. The data revealed that the wild-type plants were stunted and consistently retained less Pi than transgenic lines, especially when grown under low-phosphate conditions. This difference in Pi retention was attributable to the enhanced Pi uptake ability in the transgenic lines. The transgenic plants translocated more Pi into the plant cell due to the enhanced enzymatic activity of plasma membrane H+-ATPase and increased Pi/H+ co-transport, which improved Pi uptake. The differential expression of ‘PHO regulon’ genes further maintained intracellular Pi homeostasis. Furthermore, GB maintained a higher photosynthesis rate, thus increasing the production and translocation of sucrose via phloem loading to enhance plant response to low-phosphate stress. We conclude that GB mediates Pi uptake and translocation by regulating physiological and biochemical processes that promote adaptation to environmental changes in Pi availability. These processes eventually lead to better growth and development of the codA-transgenic lines. This finding will help to further elucidate the signaling mechanism of how GB perceives and transmits low-phosphate signals to alleviate Pi nutritional stress
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