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The continuous development of special diver underwater portable equipment has led to the continuous progress of the intelligent ocean trans-media internet of things, and has made the construction of underwater body area networks increasingly concerning for countries. Based on this, this study discusses the layered system architecture of an underwater body area network, focusing on hot issues such as network standardization design and robust information transmission in the design process of underwater body area networks, and provides a solution. This study can provide a reference for the construction and optimization of underwater body area networks for divers.

To alleviate the difficulty in detecting and recognizing erect rail barricades, a forward-looking three-dimensional(3D) imaging sonar is used to improve the effectiveness of erect rail barricade recognition, and a single shot detector(SSD)-based 3D point cloud(PCSSD) target recognition method is proposed. First, the original beam domain data are processed using a threshold filter and pass-through filter. Next, forward projection of the filtered 3D point cloud data is performed, and the grayscale depth image and pseudo color depth image are obtained. The SSD was then used to recognize the targets from the pseudo color depth image. Subsequently, the depth range of the selected targets is calculated based on the characteristics of the targets recognized from the grayscale depth image. Finally, erect rail barricades in the form of 3D point clouds were detected by combining the two-dimensional detection results and the corresponding depth range. A feature extraction block based on the multi-scale attention mechanism was proposed, and a novel target detector SSD-MV3ME was used for the design. On the 3D point cloud erect rail barricades dataset GTZ, under the condition of the same detection time, the detection accuracy of SSD-MV3ME was higher than that of the lightweight target detection model SSD-MV3 by 1.05%, and the model parameters had less than 2 482 kB. The results show that the PCSSD based on SSD-MV3ME is more suitable for erect rail barricade recognition tasks.

To solve the problem of signal-to-noise ratio(SNR) estimation for dynamic communication, an SNR estimation method suitable for underwater acoustic adaptive communication in trans-media heterogeneous networks was proposed. The minimum mean square error SNR estimation algorithm was improved by using the reconstructed data in the process of a low pilot occupancy channel estimation algorithm to achieve SNR tracking under time-varying channel conditions. Simulation results show that the proposed method can obtain highly accurate SNR estimation results under high SNR conditions, and the SNR estimation results can decline rapidly under low SNR conditions, which is particularly suitable for the rate-adjustment strategy of link adaptive communication. The adaptive rate adjustment strategy given by the proposed method can effectively reduce the power consumption and improve the communication data rate.

Abstract Exchange of mobile functional genes within microbiota benefits the microbial community. However, the status of the mobile gene pool in environment is still largely unclear, impeding the understanding on the process of gene transfer in natural microbial communities. The release of extracellular vesicles (EVs) by diverse organisms has been proposed to be a vital way in the complex networks of interactions between microbes and their habitats. In this study, we hypothesized that microbial EVs encapsulating functional DNA are widely distributed in the environmental matrix. The prevalence, source and DNA cargoes of EVs in three types of typical microbial habitats were studied. High abundance of EVs comparable to the bacterial concentration was found in human faeces, wastewater and soil. Metagenomic analysis showed the diverse and differential taxonomy of EVs‐associated DNA compared to source microbiome. An array of efficient EVs producing species was identified. A wide variety of mobile genes including glycoside hydrolase family 25 were enriched. Antibiotic resistance genes co‐localizing with mobile genetic elements were abundant in the EVs. This study provides novel insights into the prevalent EVs as a reservoir for the mobile functional genes in the natural environment.

The marine biological sonar system evolved in the struggle of nature is far superior to the current artificial sonar. Therefore, the development of bionic underwater concealed detection is of great strategic significance to the military and economy. In this paper, a generative adversarial network (GAN) is trained based on the dolphin vocal sound dataset we constructed, which can achieve unsupervised generation of dolphin vocal sounds with global consistency. Through the analysis of the generated audio samples and the real audio samples in the time domain and the frequency domain, it can be proven that the generated audio samples are close to the real audio samples, which meets the requirements of bionic underwater concealed detection.