MSF-Net: A Multilevel Spatiotemporal Feature Fusion Network Combines Attention for Action Recognition

An action recognition network that combines multi-level spatiotemporal feature fusion with an attention mechanism is proposed as a solution to the issues of single spatiotemporal feature scale extraction,information redundancy,and insufficient extraction of frequency domain information in channels in 3D convolutional neural networks.Firstly,based on 3D CNN,this paper designs a new multilevel spatiotemporal feature fusion(MSF)structure,which is embedded in the network model,mainly through multilevel spatiotemporal feature separation,splicing and fusion,to achieve the fusion of spatial perceptual fields and short-medium-long time series information at different scales with reduced network parameters;In the second step,a multi-frequency channel and spatiotemporal attention module(FSAM)is introduced to assign different frequency features and spatiotemporal features in the channels are assigned corresponding weights to reduce the information redundancy of the feature maps.Finally,we embed the proposed method into the R3D model,which replaced the 2D convolutional filters in the 2D Resnet with 3D convolutional filters and conduct extensive experimental validation on the small and medium-sized dataset UCF101 and the largesized dataset Kinetics-400.The findings revealed that our model increased the recognition accuracy on both datasets.Results on the UCF101 dataset,in particular,demonstrate that our model outperforms R3D in terms of a maximum recognition accuracy improvement of 7.2%while using 34.2%fewer parameters.The MSF and FSAM are migrated to another traditional 3D action recognition model named C3D for application testing.The test results based on UCF101 show that the recognition accuracy is improved by 8.9%,proving the strong generalization ability and universality of the method in this paper.

海外新移民的回流研究——以闽西北新兴侨乡归县为例

人口迁移作为人类社会的一种自然现象,在全球化时代,加速了世界人口的流动。随着国际移民跨国流动的日益频繁,移民回流现象也日益增多。我国是世界主要移民来源国之一,在海外移民潮持续扩大的同时,也迎来了越来越多的新移民返迁。本文以闽西北归县这个新兴侨乡为个案,借助国外已有的关于移民回流问题的相关理论,对新移民回流的规模、类型、模式、回流的动因进行深入探讨。笔者认为,新移民回流的产生和发展受到来自移居国社会与祖籍地的社会双重作用力的影响。此外,个人主观能动性在其中也发挥着至关重要的作用。"去与留"是新移民在基于多方面因素进行权衡下做出个人主观能动性的选择。

Self-assembled natural phytochemicals for synergistically antibacterial application from the enlightenment of traditional Chinese medicine combination

The application of nanotechnology for antimicrobial delivery has capacity to improve anti-bacterial efficacy.Currently,the usage of various inorganic and organic carriers,such as metal ions,nano-silicon and surfactants,might increase the potential toxicity of nanoparticles and make their clinical transformation more difficult.Herein,a nano-delivery system was constructed by direct self-assembly of antibacterial phytochemicals(berberine and rhein)originated from traditional Chinese medicine Coptis chinensis Franch.and Rheum palmatum L.,respectively.Combining X-ray single crystal diffraction,nuclear magnetic resonance and other spectra characterizations,the stacked structure of nanoparticles was profoundly demonstrated.Briefly,rhein acted as the layered backbone and berberine embedded in it.In vitro bacteriostasis experiment showed the minimum bactericidal concentration of nanoparticles was 0.1μmol/mL,which was lower than that of berberine and rhein.The results of confocal laser scanning microscope,biofilm quantitive assay and scanning electron microscopy indicated that nanoparticles had strong inhibitory effects on Staphylococcus aureus biofilm.More importantly,transmission electron microscopy and mass spectra indicated the further bacteriostatic mechanism of nanoparticles.Meanwhile,the nanoparticles had well biocompatibility and safety.Current study will open up new prospect that the design of self-assemblies between active phytochemicals can be originated from traditional Chinese medicine combination.