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926 results on '"Li, Zhongyi"'

1. Joint Beamforming for Multi-target Detection and Multi-user Communication in ISAC Systems

Author

Zhao, Zongyao, Liu, Zhenyu, Jiang, Rui, Li, Zhongyi, Zhang, Xiao-Ping, Tang, Xinke, and Dong, Yuhan

Subjects
Electrical Engineering and Systems Science - Signal Processing
Abstract

Detecting weak targets is one of the main challenges for integrated sensing and communication (ISAC) systems. Sensing and communication suffer from a performance trade-off in ISAC systems. As the communication demand increases, sensing ability, especially weak target detection performance, will inevitably reduce. Traditional approaches fail to address this issue. In this paper, we develop a joint beamforming scheme and formulate it as a max-min problem to maximize the detection probability of the weakest target under the constraint of the signal-to-interference-plus-noise ratio (SINR) of multi-user communication. An alternating optimization (AO) algorithm is developed for solving the complicated non-convex problem to obtain the joint beamformer. The proposed scheme can direct the transmit energy toward the multiple targets properly to ensure robust multi-target detection performance. Numerical results show that the proposed beamforming scheme can effectively increase the detection probability of the weakest target compared to baseline approaches while ensuring communication performance., Comment: 5 pages, 4 figures, submitted to IEEE journal

Published
2024

36. Experimental Study on Sloshing Characteristics of Accumulator under Ocean Condition

Author

WEI Tianyi;ZHANG Biao;TAN Sichao;LI Dongyang;LI Zhongyi

Subjects
accumulator, liquid sloshing, ocean condition, pressure measurement, visualization, non-plane wave, Nuclear engineering. Atomic power, TK9001-9401, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The development of marine resources and the construction of coastal islands need a reliable energy supply. The floating nuclear power plant (FNPP) is a combination of small nuclear reactors and offshore platforms, and it can be used in many fields such as offshore power supply, combined heat and power, and seawater desalination treatment. FNPP has the advantages of high power density, sustainable power generation, and low carbon emission. But due to environmental factors such as wind and waves on the sea or ship navigation, FNPP will generate complex motions in actual sea conditions. Liquid sloshing will occur in accumulators and other liquid storage tanks subjected to additional inertial forces under moving conditions. The free surface fluctuation will disturb the measurement of critical parameters such as liquid level, and the fluid impact load will affect the operation and maintenance of equipment. So measurement experiments were carried out based on the 6-DOF motion platform to study the sloshing characteristics and pressure variation rule of the accumulator. The pressure surge was studied by multi-directional pressure sensors, the free surface sloshing process was obtained by the high-speed camera system, and the natural frequency of the accumulator was obtained according to the model equivalent and mathematical analysis. The results show that under rolling motions, the pressure variation period is consistent with the motion period and the pressure amplitude can be determined by motion angle. The motion forms of liquid surface are basically stationary waves and marginal hydraulic jump, and the pressure measurement results show a regular sine and cosine variation, so the system analysis model under rolling conditions can be reasonably simplified based on the above analysis and safety margin assessment. Under horizontal sloshing, the additional inertial force will induce many kinds of nonlinear liquid surface sloshing. Based on time and frequency domain analysis, it can be seen that the pressure variation rule is mainly dominated by natural frequency, excitation frequency, and frequency multiplication. The pressure variation amplitude increases sharply and reaches the peak value under resonance conditions. There are unstable evolution processes and chaotic sections of pressure surge under specific sloshing conditions, where the pressure variation has randomness and initial value sensitivity. In addition, the breaking and rotation of the free surface will occur near the resonance frequency. Under the coupled motion, the pressure at the measurement point is affected by the characteristics of single degree of freedom motion and the coupling form of different motion. The coupled motion can be disassembled and analyzed based on considering the phase difference. In summary, the study can provide an analytical basis for sloshing research of liquid storage equipment and provide a reference for structural improvement and sloshing suppression optimization.

Published
2023
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38. Design and Performance Analysis of Compliant Actuator Mechanism with Variable Stiffness

Author

Liu Rong, Zheng Zhizhen, Qin Huibin, Li Zhongyi, and Bai Shaoping

Subjects
Variable stiffness, Compliant actuator mechanism, Reconfigurable, Four-bar linkage with a zero-length rack, Mechanical engineering and machinery, TJ1-1570
Abstract

Controllable variable stiffness compliant actuator mechanism has the characteristics of high compliance, high environmental adaptability and good man-machine interaction. The variable stiffness compliant actuator mechanism is based on the transmission principle of a four-bar linkage with a zero-length rack. The variable stiffness control can be realized by changing the properties and the winding mode of the elastomer, or the configuration scheme. Through configuration analysis and structure design, the stiffness and torque models of the compliant actuator mechanism are established to reveal its stiffness behavior. The Lagrangian method is used to establish the dynamic model of the compliant actuator mechanism, and the frequency theoretical results are obtained by solving the average stiffness. The virtual prototype is established to motion simulation, which reveals its performance characteristics and verifies the correctness of theoretical analysis. Compared with other similar designs, the compliant actuator mechanism proposed has the characteristics of miniaturization and lightweight with strong applicability. It can be used as a single module and integrated into the exoskeleton system.

Published
2022
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42. Large-scale high uniform optoelectronic synapses array for artificial visual neural network.

Author

Zhang, Fanqing, Li, Chunyang, Chen, Zhicheng, Tan, Haiqiu, Li, Zhongyi, Lv, Chengzhai, Xiao, Shuai, Wu, Lining, and Zhao, Jing

Subjects
CONVOLUTIONAL neural networks, RECOGNITION (Psychology), VISUAL memory, GOLD nanoparticles, MEDICAL sciences
Abstract

Recently, the biologically inspired intelligent artificial visual neural system has aroused enormous interest. However, there are still significant obstacles in pursuing large-scale parallel and efficient visual memory and recognition. In this study, we demonstrate a 28 × 28 synaptic devices array for the artificial visual neuromorphic system, within the size of 0.7 × 0.7 cm2, which integrates sensing, memory, and processing functions. The highly uniform floating-gate synaptic transistors array were constructed by the wafer-scale grown monolayer molybdenum disulfide with Au nanoparticles (NPs) acting as the electrons capture layers. Various synaptic plasticity behaviors have been achieved owing to the switchable electronic storage performance. The excellent optical/electrical coordination capabilities were implemented by paralleled processing both the optical and electrical signals the synaptic array of 784 devices, enabling to realize the badges and letters writing and erasing process. Finally, the established artificial visual convolutional neural network (CNN) through optical/electrical signal modulation can reach the high digit recognition accuracy of 96.5%. Therefore, our results provide a feasible route for future large-scale integrated artificial visual neuromorphic system. [ABSTRACT FROM AUTHOR]

Published
2025
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44. Safety and efficacy of three enteral feeding strategies in patients with severe stroke in China (OPENS): a multicentre, prospective, randomised, open-label, blinded-endpoint trial

Author

Jiang, Wen, Yang, Fang, Zhao, Jingjing, Yuan, Fang, Song, Changgeng, Sun, Lili, Zhao, Yuanfang, Wei, Jiangya, Liu, Lijuan, Hu, Mengmeng, Wang, Xuan, Zhang, Jingjing, Shi, Xiaodan, Hui, Bo, Chen, Rong, Ren, Xianhui, Du, Fang, Yin, Rong, Wei, Yaxuan, Li, Yuanming, Chang, Mingze Chang, Zhang, Xiujuan, Yin, Yanling, Zhang, Wei, Guo, Jun, Guo, Peng, Lu, Jiarui, Li, Chuan, Shen, Jinjin, Bai, Miao, Zhang, Min, Zhang, Bei, Zhang, Shijun, Bai, Yulan, Bai, Yanan, Fan, Wenjun, Wang, Lin, Yu, Fangfang, Ru, Yanni, Wei, Wei, Ma, Yaling, Wang, Wenzong, Hu, Ruoruo, Li, Yajuan, Ma, Xuemei, Lv, Tao, Yu, Liping, Zhu, Hao, Yang, Linsong, Wu, Yaxin, Cao, Junxia, Jia, Yi, Wu, Tao, Zhang, Hongxing, Liu, Saibing, Ning, Bo, Song, Chaohui, Zhao, Hongyan, Li, Zhongyi, Zhang, Haiyan, Wang, Mingming, Song, Yongbin, Zhu, Yong, Wang, Chengkai, Chen, Siwen, Ren, Qianmeng, Lu, Shuang, Wang, Xinlai, You, Qiufeng, Liu, Zhiqin, Jiang, Yi, Xiong, Jing, Wang, Xiaocheng, Zhao, Rong, Huo, Kang, Chen, Chen, Qu, Yongcai, Ma, Li, Yang, Xiai, Liu, Yi, Wang, Xingsheng, Chang, Mingze, and Shang, Lei

Published
2022
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48. Design of a Reconfigurable Novel Constant-Force Mechanism for Assistive Exoskeletons

Author

Liu, Yichen, Li, Zhongyi, Bai, Shaoping, Ceccarelli, Marco, Series Editor, Agrawal, Sunil K., Advisory Editor, Corves, Burkhard, Advisory Editor, Glazunov, Victor, Advisory Editor, Hernández, Alfonso, Advisory Editor, Huang, Tian, Advisory Editor, Jauregui Correa, Juan Carlos, Advisory Editor, Takeda, Yukio, Advisory Editor, Zeghloul, Saïd, editor, Laribi, Med Amine, editor, and Arsicault, Marc, editor

Published
2021
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