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Evaluation of lightning-induced overvoltage on a 10 kV distribution line based on electromagnetic return-stroke model using finite-difference time-domain

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High Voltage 2024年第2期9卷 356-366页

作者： Pan Duan Lianfang Zhang Xiaogang Huang Jian Sun Yue Qi Qing Yang School of Automation Chongqing University of Posts and TelecommunicationsChongqingChina Chongqing Power Co Tongnan BurChongqingChina China Southern Power Grid Science Research Institute GuangzhouChina State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina

Accurate simulation of lightning-induced overvoltage for overhead distribution lines is helpful to prevent lightning trip *** electromagnetic return-stroke model was used to represent lightning and then a 3D finite-difference time-domain(FDTD)method was adopted to simulate the lightning-induced overvoltage on a distribution line without a field-line coupling *** lightning-induced overvoltage behave for different ground conductivity and varying distance between the distribution line and the lightning channel was *** results showed that the overvoltage waveforms at the centre point of the line corresponding to lightning strikes on the lossy ground and an ideal ground(σ=∞)were similar;however,the peak amplitudes of the waveform were affected by soil conductivity at a close *** relationship between magnitude of the overvoltage and distance can be described by a second-order exponential decay ***,the overvoltage calculated using the proposed model was compared with those obtained based on Agrawal's model and measurements made using the newly developed intelligent insulator on *** these comparisons,it could be concluded that the FDTD method with the electromagnetic return-stroke model produces reasonably accurate results of the attenuated oscillation waveform,which can better reproduce the overvoltage on operational distribution lines.

关键词： lightning distribution return

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MDRN: Multi-distillation residual network for efficient MR image super-resolution

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Mathematical Biosciences and Engineering 2024年第10期21卷 7421-7434页

作者： Deng, Liwei Chen, Jingyi Yang, Xin Huang, Sijuan Heilongjiang Provincial Key Laboratory of Complex Intelligent System and Integration School of Automation Harbin University of Science and Technology Heilongjiang Harbin150080 China State Key Laboratory of Oncology in South China Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy Guangdong Provincial Clinical Research Center for Cancer Sun Yat-sen University Cancer Center Guangdong Guangzhou510060 China Guangdong Esophageal Cancer Institute Guangdong Guangzhou510060 China

Super-resolution (SR) of magnetic resonance imaging (MRI) is gaining increasing attention for being able to provide detailed anatomical information. However, current SR methods often use the complex convolutional network for feature extraction, which is difficult to train and not suitable for limited computation resources in the medical scenario. To tackle these bottlenecks, we propose a multidistillation residual network (MDRN) for more differential feature refinement, which has a superior trade-off between reconstruction accuracy and computation cost. Specifically, a novel feature multidistillation residual block with a contrast-aware channel attention module was designed to make the residual features more focused on low-vision information, which maximizes the power of MDRN. Comprehensive experiments demonstrate the superiority of our MDRN over state-of-the-art methods in reconstruction quality and efficiency. Our method outperforms other existing methods in peak signal-noise ratio by up to 0.44-1.82 dB in 4× scale when GPU memory and runtime are lower than in other SR methods. The source code will be available at https://***/Jennieyy/MDRN. © 2024 the Author(s).

关键词： Magnetic resonance imaging

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Programmatic Synthesis Method for Extracted Pole Filters 15

Programmatic Synthesis Method for Extracted Pole Filters

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15th International Conference on Microwave and Millimeter Wave technology, ICMMT 2023

作者： Wu, Qing-Qiang Wu, Di-Si Long, Qiao Gong, Hong-Wei Nan, Shen Shen, Tian State Key Laboratory of Mobile Network and Mobile Multimedia Technology Department of Rhp System Zte Corporation Shen Zhen518055 China

ISBN: (纸本)9798350338874

In this paper, a method of converting in-line filters with frequency-variable couplings into extracted pole filters is studied. The concrete steps and theory are given, and the programmatic synthesis method for the coupling matrix of extracted pole filters is introduced. The extracted pole filter is favored by its flexible structure layout. However, the traditional synthesis of a extracted pole filter requires a large quantity of calculation and extraction steps, and it is very difficult to form a programmatic synthesis process. With the development of frequency-variable coupling technology, the programmatic synthesis of filters with frequency-variable couplings has matured based on matrix rotation and scaling. Based on these principles, this paper further studies how to extend the programmatic synthesis to the extracted pole structures, so as to simplify the design of the extracted pole filters. © 2023 IEEE.

关键词： Flexible structures

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Research on Startup and Emergency Braking Strategy of Doubly-Fed Induction-Machine-Based Flywheel Energy Storage system 26

Research on Startup and Emergency Braking Strategy of Doubly...

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26th International Conference on Electrical Machines and systems, ICEMS 2023

作者： Zhao, Jinglin Li, Hui Xiang, Xuewei Li, Wendong Chongqing University State Key Laboratory of Power Transmission Equipment & System Security and New Technology School of Electrical Engineering Chongqing China

ISBN: (纸本)9798350317589

This paper proposes control strategies for startup and emergency braking procedures of Doubly-Fed InductionMachine-Based Flywheel Energy Storage system (DFIM-FESS). For startup procedure, short-circuit the stator and simplify the stator Flux Oriented Control (FOC) by ignoring the transient part of the voltage equation based on flywheel characteristics, then perform the rotor currents control can output large electromagnetic torque and increasing speed stably. For emergency braking procedure, the rotor is two-phase short-circuited connect to DC source, the stator is connected to the braking resistance, then analyze the constraint conditions of the system, and propose the method to get the suitable parameters of the brake resistance and the DC excitation resource. The simulation results verify the effectiveness of the control strategies and configuration method of equipment parameters. © 2023 IEEE.

关键词： Flywheels

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Sliding mode-based adaptive tube model predictive control for robotic manipulators with model uncertainty and state constraints

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Control Theory and technology 2023年第3期21卷 334-351页

作者： Erlong Kang Yang Liu Hong Qiao State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of AutomationChinese Academy of SciencesBeijing 100190China Beijing Key Laboratory of Research and Application for Robotic Intelligence of Hand-Eye-Brain Interaction Beijing 100190China The School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China University of Chinese Academy of Sciences Beijing 100049China CAS Center for Excellence in Brain Science and Intelligence Technology Shanghai 200031China

In this paper,the optimal tracking control for robotic manipulators with state constraints and uncertain dynamics is investigated,and a sliding mode-based adaptive tube model predictive control method is ***,utilizing the high-order fully actuated system approach,the nominal model of the robotic manipulator is constructed as the predictive *** on the nominal model,a nominal model predictive controller with the sliding mode is designed,which relaxes the terminal constraints,and realizes the accurate and stable tracking of the desired trajectory by the nominal ***,an auxiliary controller based on the node-adaptive neural networks is constructed to dynamically compensate nonlinear uncertain dynamics of the robotic ***,the estimation deviation between the nominal and actual states is limited to the tube invariant *** the same time,the recursive feasibility of nominal model predictive control is verified,and the ultimately uniformly boundedness of all variables is proved according to the Lyapunov ***,experiments show that the robotic manipulator can achieve fast and efficient trajectory tracking under the action of the proposed method.

关键词： Tube-based model predictive control-robotic manipulator Sliding mode Node-adaptive neural networks Model uncertainty

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Research on Efficient Network Switching and Load Balancing Algorithm Based on Ad-Hoc Network

Research on Efficient Network Switching and Load Balancing A...

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International Conference on Guidance, Navigation and Control, ICGNC 2022

作者： Wu, Wanqing Dong, He He, Chenglong State Key Laboratory of Satellite Navigation System and Equipment Technology The 54th Research Institute of CETC Shijiazhuang050081 China

ISBN: (纸本)9789811966125

Aiming at the problems of poor scalability of Ad-Hoc flat network and unbalanced load in clustered network, we proposed an efficient dynamic network switching and load balancing algorithm based on Ad-Hoc network. First, we initialize the network and quickly build the initial two-layer network topology. Then, according to the state of the network, the node mode is dynamically converted. Finally, according to the load situation of the upper nodes in the network, the network topology is dynamically adjusted to achieve network load balancing. The experimental results show that the network topology establishment period is 20 s, the single node access time is 2 s, the average mode transition delay of cluster member-cluster head is 1.993 s, the average mode transition delay of cluster head-cluster member is 1.142 s, and the network topology dynamic maintenance period does not exceed 2 s. Therefore, the algorithm we proposed can quickly build a two-layer network topology, has efficient dynamic network switching capability and can achieve load balancing. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Network topology

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LQR-based Ground Resonance Suppression of Helicopter with Adaptive Landing Gear

LQR-based Ground Resonance Suppression of Helicopter with Ad...

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2022 IEEE International Conference on robotics and Biomimetics, ROBIO 2022

作者： Yan, Zhen Yu, Haitao Xia, Jifeng Tian, Baolin Gao, Haibo State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China

ISBN: (纸本)9781665481090

Ground resonance (GR) is a potentially destructive mechanical instability involving the coupling of the regressive rotor mode to the fuselage motion. Vibration can be disastrous if measures are not taken in time to mitigate vibrations. This paper presents a study on the use of adaptive landing gear to eliminate GR in helicopters. A GR model considering adaptive landing gear is established, and the dynamic characteristics of the system are analyzed. In this paper, the Linear Quadratic Regulator (LQR) controller is applied to suppress the GR. The setting of the weighting matrix coefficients directly determines the effect of the control system. Therefore, a design method of LQR weighting matrix based on multi-objective genetic algorithm is proposed, which enables the control system to meet multiple performance indicators concurrently. Numerical simulations of GR suppression were performed for the rotor speed range where GR is most likely to occur. The results show that even if the rotor system is not equipped with any dampers, the suppression of helicopter GR can be achieved by using the control strategy proposed in this paper to control the adaptive landing gear. Therefore, the application of adaptive leg landing gear to helicopters can provide some ideas to eliminate GR. © 2022 IEEE.

关键词： Multiobjective optimization

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Photonics-assisted intensity-modulation and direct-detection MIMO millimeter-wave system in the D-band

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Chinese Optics Letters 2025年第1期23卷 7-12页

作者： Jingwen Tan Peng Tian Jianjun Yu Xianming Zhao Xinglin Dou Long Zhang Xiongwei Yang YangHan Yi Wei Bing Zhang Qinyi Zhang Luhan Jiang Weiping Li Rahim Uddin Kaihui Wang Wen Zhou State Key Laboratory of ASIC and System Key Laboratory for Information Science of Electromagnetic Waves(MoE)School of Information Science and TechnologyFudan UniversityShanghai 200433China Beijing Hongshan Information Technology Research Institute Co. Ltd.Beijing 100176China

We experimentally demonstrate the transmission of discrete multi-tone(DMT)millimeter-wave(mm-wave)signals over a 1.2-km distance at the D-band(110–170 GHz)in a cost-effective intensity-modulation and direct-detection(IM/DD)communication *** the experiment,we successfully achieve the transmission of DMT-QPSK and DMT-16QAM mm-wave signals over multiple-input multiple-output(MIMO)*** the 1.2-km free-space transmission,the bit error rate(BER)of the DMT-16QAM is below the 25%soft decision forward error correction(25%SD-FEC)threshold of 4×10^(-2),with a maximum net bit rate of 24.62 Gbit/s achieved in this system.

关键词： D-band discrete multi-tone intensity modulation and direct detection long-distance wireless transmission photonics-assisted technique

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Application and analysis of integrated sensing and communication technology based on millimeter wave

Application and analysis of integrated sensing and communica...

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2022 Conference on Infrared, Millimeter, Terahertz Waves and Applications, IMT 2022

作者： Li, Yitong Cao, Weilin Song, Ruiliang Ma, Tianyi Liu, Ning Sun, Niefeng Beijing100043 China State Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang050081 China Shijiazhuang050051 China

ISBN: (纸本)9781510662476

Integrated sensing and communication (ISAC) technology based on millimeter wave (mm-wave) is an important component and key direction of the development of 5G and next generation(6G). It is widely used in a variety of new vertical application scenarios, such as satellite Internet, smart city, smart transportation, intelligent manufacturing and smart home. With the continuous maturity of mm-wave radio frequency (RF) and large-scale multiple input multiple output (MIMO) technology, the integration of communication equipment terminal and intelligent sensing system becomes possible. The beam characteristics of mm-wave make it have high resolution in both time domain and angle domain. Therefore, the ISAC technology based on mm-wave frequency band is the most realizable technical scheme at present. Based on the latest progress of mm-wave ISAC technology, this paper studies the new applications and key technologies in the future ISAC field, and provides a technical development idea for the deep integration of 6G high-speed wireless communication and multiple sensing forms. © 2023 SPIE.

关键词： Millimeter waves

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Research on Multi-domain Data Transmission and Presentation Algorithm Based on WiFi Network 11th

Research on Multi-domain Data Transmission and Presentation ...

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11th International Conference on Communications, Signal Processing, and systems, CSPS 2022

作者： Wu, Wanqing Yu, Baoguo Dong, He Yi, Qingwu He, Chenglong State Key Laboratory of Satellite Navigation System and Equipment Technology The 54Th Research Institute of CETC Shijiazhuang050081 China

ISBN: (纸本)9789819912599

Aiming at the perception and visualization of multi-domain data in indoor and outdoor environments, we proposed a multi-domain data transmission and presentation method based on WiFi networking. First, the multi-domain data sensed by distributed nodes is preprocessed to remove abnormal data and convert it into a standard format. Then, the distributed nodes conduct WiFi networking, and transmit the multi-domain data to the fixed node, and the fixed node forwards the received data to the multi-domain data processing and display platform. Finally, the multi-domain data processing and display platform uses the graphing algorithm to visualize the multi-domain data. The experimental results show that the algorithm we proposed can effectively solve the problem of reliable transmission and mapping of multi-domain data in unknown environments. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Data transfer

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