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Aerodynamic Performance of Three Flapping Wings with Unequal Spacing in Tandem Formation

Journal of Bionic Engineering 2024年第4期21卷 1662-1676页

作者： Min Chang Ziyi Xu Zengshuang Chen Li Li Xueguang Meng Unmanned System Research Institute National Key Laboratory of Unmanned Aerial Vehicle TechnologyNorthwestern Polytechnical UniversityXi’an710072People’s Republic of China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an710049People’s Republic of China Xi’an Aeronautics Computing Technique Research Institute Aviation Industry Corporation of ChinaXi’an710076People’s Republic of China

To better understand the aerodynamic reasons for highly organized movements of flying organisms,the three-flapping wing system in tandem formation was studied numerically in this *** from previous relevant studies on the multiple flapping wings that are equally spaced,this study emphasizes the impact of unequal spacing between individuals on the aerodynamics of each individual wing as well as the whole *** is found that swapping the distance between the first and second wing with the distance between the second wing and the rearmost wing does not affect the overall aerodynamic performance,but significantly changes the distribution of aerodynamic benefits across each *** the whole flapping cycle,three effects are at *** narrow channel effect and the downwash effect can promote and weaken the wing lift,respectively,while the wake capture effect can boost the *** also shows that these effects could be manipulated by changing the spacing between adjacent *** findings provide a novel way for flow control in tandem formation flight and are also inspiring for designing the formation flight of bionic aircraft.

关键词： Three flapping wings Unequal spacing Aerodynamic performance Tandem formation

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Hardware-Free Event Cameras Temporal Synchronization Based on Event Density Alignment 1

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16th International Conference on Intelligent robotics and Applications, ICIRA 2023

作者： Li, Wenxuan Dong, Yan Qiu, Shaoqiang Han, Bin State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and Technology Hubei Wuhan430074 China Guangdong Intelligent Robotics Institute Dongguan523106 China

ISBN: (数字)9789819964987

ISBN: (纸本)9789819964970

Event cameras are a novel type of sensor designed for capturing the dynamic changes of a scene. Due to factors such as trigger and transmission delays, a time offset exists in the data collected by multiple event cameras, leading to inaccurate information fusion. Thus, the collected data needs to be synchronized to overcome any potential time offset issue. Hardware synchronization methods require additional circuits, while certain models of event cameras (e.g., CeleX5) do not support hardware synchronization. Therefore, this paper proposes a hardware-free event camera synchronization method. This method determines differences between start times by minimizing the dissimilarity of the event density distributions of different event cameras and synchronizes the data by adjusting timestamps. The experiments demonstrate that the method's synchronization error is less than 10 ms under various senses with multiple models of event cameras. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.

关键词： Cameras

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Design,synthesis and biological evaluation of Leu_(10)-teixobactin analogues

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Chinese Chemical Letters 2025年第4期36卷 157-161页

作者： Yanye Fan Jingjing Chen Bichun Chen Jinyu Bai Bowen Yang Feng Liang Lijing Fang The State Key Laboratory of Refractories and Metallurgy School of Chemistry and Chemical EngineeringWuhan University of Science and TechnologyWuhan 430081China Guangdong Key Laboratory of Nanomedicine CAS-HK Joint Lab of BiomaterialsACS Key Laboratory of Biomedical Imaging Science and SystemInstitute of Biomedicine and BiotechnologyShenzhen Institute of Advanced Technology(SIAT)Chinese Academy of SciencesShenzhen 518055China University of Chinese Academy of Sciences Beijing 100049China Sino-Euro Center of Biomedicine and Health Shenzhen 518024China School of Pharmacy Lanzhou UniversityLanzhou 730000China

Two thioamino acids and four fiuorinated amino acids were employed to substitute either partially or entirely the Ile_(2),Ser_(3),Ile_(6),and Ser_(7) residues of Leu_(10)-teixobactin to prepare ten analogues and the bioactivity of them was *** SAR studies revealed that Ile_(6) was tolerable for both thioamidation and fiuoridation,while Ser_(7) was identified as the most tolerable site for *** 1a demonstrated comparable or slightly improved antibacterial activity,superior protease stability compared to Leu_(10)-teixobactin,while not exhibiting obvious cytotoxicity against mammalian cells.

关键词： Leu_(10)-teixobactin Thioamidation Fluorination Antibacterial activity Protease stability

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CASKA-CRT: Chinese Remainder Theorem Empowered Certificateless Aggregate Signcryption Scheme with key Agreement in IoVs

IEEE Transactions on Intelligent Vehicles

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IEEE Transactions on Intelligent Vehicles 2024年 1-16页

作者： Hou, Yingzhe Cao, Yue Xiong, Hu Sun, Zhili Mumtaz, Shahid Tian, Daxin School of Cyber Science and Engineering Wuhan University Wuhan China School of Information and Software Engineering University of Electronic Science and Technology of China Chengdu China Institute of Communication Systems University of Surrey Guildford U.K Department of Applied Informatics Silesian University of Technology Akademicka Gliwice Poland State Key Laboratory of Vehicle-Infrastructure Integrated ITS the State Key Laboratory of Intelligent Transportation System and the School of Transportation Science and Engineering Beihang University Beijing China

To enhance the privacy of messages in Internet of Vehicles (IoVs), it is critical to preserve the communication security between Road Side Unit (RSU) and numerous vehicles. The primitive of signcryption is introduced to guarantee the confidentiality, integrity and unforgeability of transmitted messages. Nevertheless, the existing signcryption schemes fail to achieve a balance between security and efficiency. In this paper, we construct a Chinese remainder theorem (CRT) empowered certificateless aggregate signcryption scheme with key agreement (CASKA-CRT). As the vehicle joins and leaves dynamically, the proposed scheme can ensure the dynamic security via one modulo division operation. Besides, the certificateless aggregate signcryption and key agreement mechanisms are embedded. The former idea can both address the certificate management and key escrow problems, while the latter technology can create authentication as a premise of secure communication. Based on this construction, the hash-to-group operation and bilinear pairing are avoided, to realize a faster verification with the increased number of messages. Moreover, the security of proposed scheme is proved under the random oracle model. Finally, the performance analysis demonstrates the advantage of CASKA-CRT in terms of security and reliability over related works. IEEE

关键词： Public key cryptography

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Coordination control method to block cascading failure of a renewable generation power system under line dynamic security

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Protection and Control of Modern Power systems 2023年第1期8卷 194-204页

作者： Jinxin Ouyang Jianfeng Yu Xiaoxuan Long Yanbo Diao Jian Wang State Key Laboratory of Power Transmission Equipment and System Security and New Technology School of Electrical EngineeringChongqing UniversityChongqingChina Information and Communication Branch of State Grid Chongqing Electric Power CompanyChongqingChina Chongqing City Management College ChongqingChina

The large application of renewable energy generation(REG)has increased the risk of cascading failures in the power *** the same time REG also provides the possibility of new approaches for the suppression of such ***,the capacity and position of the synchronous generator(SG)involved in regulation limit the power regu-lation speed(PRS)of REG to the overload line which is the main cause of cascading failures,while the PRS of SG is related to the position and shedding *** and SGs have difficulty in achieving effective cooperation under constraints of system power ***,the dynamic variation of line flow during power regulation causes new problems for the accurate evaluation of line thermal safety under ***,a new strategy for quan-titatively coordinating shedding power and power regulation to block cascading failures in the dynamic security domain is proposed in this *** control capability and dynamic security domain of the overload line are mod-eled,and the coordination control method based on power regulation is then proposed to minimize shedding *** algorithm for the optimal control scheme considers the constraints of load capacity,power source capacity and bus *** correctness of the proposed method is verified using case studies.

关键词： Cascading failures Overload Shedding power Power regulation Thermal stability

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Attribute Analysis and Modeling Research on Color Harmony of Three-Color Combination

Attribute Analysis and Modeling Research on Color Harmony of...

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2023 International Conference on Culture-Oriented Science and technology, CoST 2023

作者： Pu, Jiapeng Wang, Shuang Ren, Hui Communication University of China State Key Laboratory of Media Convergence and Communication China Communication University of China Key Laboratory of Acoustic Visual Technology and Intelligent Control System China Communication University of China Beijing Key Laboratory of Modern Entertainment Technology Beijing China

ISBN: (纸本)9798350357998

Color harmony is the result of objective color matching and human subjective feeling. This paper aims to study the subjective and objective factors of color harmony and carry out mathematical models between them. Firstly, we constructed a color data set commonly used three-color combinations. Secondly, we analyzed the subjective and objective factors affecting color harmony, extracted the 36-dimensional objective physical features, and divided subjective factors into direct psychological factors and indirect psychological factors. Then, based on color harmony and its subjective factors, a total of 33 subjects evaluated 150 three-color combinations on a five-level scale. Finally, the mathematical models of color harmony were constructed by machine learning algorithms. The research shows that color harmony is not only affected by objective factors, but also by subjective factors, and the influence of subjective factors is greater. In addition, the multiple linear regression algorithm plays best on color harmony predicting, which can better explain the color harmony mechanism. © 2023 IEEE.

关键词： Color matching

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A SINS Error Correction Approach Based on Dual-Threshold ZV Detection and Cubature Kalman Filter

A SINS Error Correction Approach Based on Dual-Threshold ZV ...

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2023 IEEE International Conference on systems, Man, and Cybernetics, SMC 2023

作者： Xu, Ruijie Chen, Shichao Sun, Wenqiao Lv, Yisheng Luo, Jialiang Tang, Ying Institute of Automation Chinese Academy of Sciences College of Information Science & Technology Beijing University of Chemical Technology The State Key Laboratory for Management and Control of Complex System State Key Laboratory of Multimodal Artificial Intelligence Systems Beijing China Institute of Automation Chinese Academy of Sciences The Center of National Railway Intelligent Transportation System Engineering and Technology China Academy of Railway Sciences Corporation Limited The State Key Laboratory for Management and Control of Complex System State Key Laboratory of Multimodal Artificial Intelligence Systems Beijing China Transportation and Economics Research Institute The Center of National Railway Intelligent Transportation System Engineering and Technology China Academy of Railway Sciences Corporation Limited Beijing China Institute of Automation Chinese Academy of Sciences The State Key Laboratory for Management and Control of Complex System State Key Laboratory of Multimodal Artificial Intelligence Systems Beijing China Institute of Automation Chinese Academy of Sciences China University of Geosciences Beijing School of Information Engineering The State Key Laboratory for Management and Control of Complex System State Key Laboratory of Multimodal Artificial Intelligence Systems Beijing China Rowan University Department of Electrical and Computer Engineering Glassboro United States

ISBN: (纸本)9798350337020

Global Navigation Satellite systems (GNSS) can provide real-time positioning information for outdoor users, but cannot for indoor scenarios or heavily occluded outdoor scenarios. Strap-down Inertial Navigation system (SINS) are widely used to locate people in complex interior or heavily occluded outdoor scenarios due to its light weight and low power consumption. However, IMU of SINS are noisy, and the sampling data error is large, which is a divergence of the error with time. Therefore, it will generate a positioning accumulation error, which affects the final positioning accuracy. The problem of cumulative IMU errors is usually dealt with by Zero-Velocity Update (ZUPT). The zero-velocity detection part of basic ZUPT method usually uses a single threshold to determine the gait of pedestrian, which often has the problem of gait misjudgment and omission. To address these problems, this paper proposes a composite conditional detection method to solve the problem of misjudgment in the zero-velocity interval. In addition, we redesign the zero-velocity update algorithm and uses the Cubature Kalman filter (CKF) for pedestrian positioning error correction. The experimental results demonstrate that the proposed ZUPT method based on dual-threshold detection can better detect the interval between pedestrian motion and stationery than ones with single threshold. The zero-velocity update algorithm based on CKF has higher performance than conventional EKF and UKF methods, which constrains the cumulative error of SINS to about 0.2% of the whole walking distance. © 2023 IEEE.

关键词： Cubature Kalman Filter Inertial Pedestrian Navigation Zero-Velocity Update

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Design and motion performance of new inspection robot for steam generator heat transfer tubes

Design and motion performance of new inspection robot for st...

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2021 IEEE International Conference on Real-Time Computing and robotics, RCAR 2021

作者： Xu, Biying Li, Ge Xing, Zhenming Cai, Hegao Zhao, Jie Fan, Jizhuang Harbin Institute of Technology State Key Laboratory of Robotics and System Heilongjiang Province Harbin China

ISBN: (纸本)9781665436786

The reliability of the Steam Generator is a key factor affecting the overall efficiency and safety of nuclear power plant reactors. Under the influence of nuclear radiation, remote control robots are currently used for Steam Generator heat transfer tubes inspection. In this paper, a new inspection robot is designed with better structure and higher working efficiency. Structural modeling and kinematic analysis are carried out. A modular control system is designed and applied for system integration. To verify the practicality of the robot, tube sheet motion experiments and performance analysis are undertaken. It results that the proposed inspection robot efficiently moves on the tube sheet and has excellent motion performance. © 2021 IEEE.

关键词： Steam generators

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Mechanism of Seebeck coefficient variation at the output of NiCr/NiSi thin film thermocouple with different wires 3

Mechanism of Seebeck coefficient variation at the output of ...

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2023 3rd International Conference on Measurement Control and Instrumentation, MCAI 2023

作者： Liu, Zhihui Guo, Tengda Cheng, Yongjun Wang, Bi Shen, Kai Hu, Kai Zhou, Jiankang Zhang, Chuanbing Wang, Zixi Ding, Wanyu State Key Laboratory of Tribology in Advanced Equipment Tsinghua University Beijing100084 China College of Materials Science and Engineering Dalian Jiaotong University Dalian116028 China Laboratory of Low Frequency Electromagnetic Communication Technology Wmcrt Cssc China State Key Laboratory of High-end Compressor and System Technology Hefei Anhui230031 China

In this paper, by using magnetron sputtering to prepare NiCr/NiSi thin film thermocouples, the static calibration method is used for NiCr/NiSi thermocouples with rapid temperature calibration experiments. Different temperature calibration curves are obtained. The Seebeck coefficient of NiCr/NiSi thin film thermocouples connected to NiCr/NiSi wires is significantly higher (41.39 μV/°C) than that of NiCr/NiSi wires (0 μV/°C). The Seebeck coefficient (41.39 μV/°C) of the NiCr/NiSi thin-film thermocouple connected to copper wire is significantly higher than that of the thermocouple connected to copper wire (0 μV/°C). The problem of the Seebeck coefficient of the K-type thermocouple is analyzed by experimental data, which provides the relevant parameter basis for the use of the K-type thermocouple. The method has the advantages of simple equipment, convenient operation, accurate and reliable data, and provides a basis for the sensor to measure the temperature measurement. © Published under licence by IOP Publishing Ltd.

关键词： Temperature measurement

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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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