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SSRN 2024年

作者： Xu, Jinsui Xu, Boyi Zhan, Hao Xie, Zhijie Tian, Zhen Lu, Yifan Wang, Zheping Yue, Honghao Yang, Fei South China University of Technology China State Key Laboratory of Robotics and System School of Mechatronics Engineering Harbin Institute of Technology Harbin150001 China Wu Xianming School of Intelligent Engineering South China University of Technology Guangzhou510641 China College of Mechanical and Electrical Engineering Northeast Forestry University Harbin150042 China Science and Technology on Space Physics Laboratory China Academy of Launch Vehicle Technology Beijing100000 China

The sensory function is crucial for achieving precise feedback control and environmental interaction in soft robots. Therefore, the multimodal sensory capabilities that mimic human fingers have always been a research hotspot. This study proposes a design method for a soft robotic gripper that can emulate the multimodal perception mechanism of human fingers and achieve high-precision recognition of grasped objects using machine learning algorithms. In addition, a finger texture structure inspired by human fingerprints is designed using a negative pressure-induced buckling method to enhance the soft gripper's ability to perceive minute surface textures. Inspired by slow adapting (SA) receptors and fast adapting (FA) receptors of human fingers, this study designs a capacitive curvature sensor (CS) and a triboelectric texture sensor (TS) to detect the size, material, and texture of objects. Furthermore, a non-contact medium identification sensor (MIS), having a sensitivity of more than 1300 times higher compared to the traditional MISs, is fabricated using the principle of electromagnetic resonance. It is shown that by employing a deep learning-based multi-channel feature fusion network, the soft grasping system with multimodal sensing can achieve an object recognition accuracy of 98.43%. This work provides an innovative approach for the application of soft robots in various fields, such as logistics sorting and food safety. © 2024, The Authors. All rights reserved.

关键词： Textures

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Frames and vertex-frequency representations in graph fractional Fourier domain

arXiv

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arXiv 2024年

作者： Shang, Linbo Zhang, Zhichao School of Mathematics and Statistics Nanjing University of Information Science and Technology Nanjing210044 China Key Laboratory of System Control and Information Processing Ministry of Education Shanghai Jiao Tong University Shanghai200240 China Key Laboratory of Computational Science and Application of Hainan Province Hainan Normal University Haikou571158 China Key Laboratory of Numerical Simulation of Sichuan Provincial Universities School of Mathematics and Information Sciences Neijiang Normal University Neijiang641000 China

Vertex-frequency analysis, particularly the windowed graph Fourier transform (WGFT), is a significant challenge in graph signal processing. Tight frame theories is known for its low computational complexity in signal reconstruction, while fractional order methods shine at unveil more detailed structural characteristics of graph signals. In the graph fractional Fourier domain, we introduce multi-windowed graph fractional Fourier frames (MWGFRFF) to facilitate the construction of tight frames. This leads to developing the multi-windowed graph fractional Fourier transform (MWGFRFT), enabling novel vertex-frequency analysis methods. A reconstruction formula is derived, along with results concerning dual and tight frames. To enhance computational efficiency, a fast MWGFRFT (FMWGFRFT) algorithm is proposed. Furthermore, we define shift multi-windowed graph fractional Fourier frames (SMWGFRFF) and their associated transform (SMWGFRFT), exploring their dual and tight frames. Experimental results indicate that FMWGFRFT and SMWGFRFT excel in extracting vertex-frequency features in the graph fractional Fourier domain, with their combined use optimizing analytical performance. Applications in signal anomaly detection demonstrate the advantages of FMWGFRFT. Copyright © 2024, The Authors. All rights reserved.

关键词： Frequency domain analysis

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Solid-State Dewetting Structure and Properties Evolution of Pt Films Deposited by Physical Vapour Deposition During Heat Treatment

SSRN

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SSRN 2023年

作者： Chen, Wei Feng, Yingrui Wang, Peng Cui, Qifeng Qiang, Zhiqing Qiao, Li Li, Qinglin School of Materials Science and Engineering Lanzhou University of Technology Lanzhou730050 China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Lanzhou730000 China Institute of Aerospace System Engineering Shanghai Shanghai201108 China Space Structure and Mechanism Technology Laboratory of China Aerospace Science and Technology Group Co.Ltd Shanghai201108 China China

To investigate the correlation between microstructure and thermal stability of Pt film, Pt films were prepared by magnetron sputtering with thicknesses of 50, 200 and 400nm, respectively and annealed up to 1273K in vacuum or ambient atmosphere. The results showed that all three heat-treated Pt films in both environments show progressively more pronounced structures of holes, hillocks, grain agglomerates and even dewed to form low-energy island structures as the temperature increases. Both the dewetting temperature and the size of the island-like structure rise with the increase of film thickness. Due to additional pressure effects in the ambient atmosphere, the average free travel between atoms decreases, and the diffusion ability is weakened, leading to a slowdown in the rate of dewetting. The resistivity of all three Pt films in both environments showed a tendency to decrease and then increase, and they all decreased to the lowest value at 873K. The decrease is due to that atomic diffusion eliminates the lattice defects such as grain boundaries inside the films. The increase in resistivity is due to the enhanced electron scattering effect caused by high temperatures, and excessive temperature leads to dewetting process in the film, agglomeration on the surface of the film also leads to an increase in resistivity. © 2023, The Authors. All rights reserved.

关键词： Heat treatment

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DNN Task Assignment in UAV Networks: A Generative AI Enhanced Multi-Agent Reinforcement Learning Approach

arXiv

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arXiv 2024年

作者： Tang, Xin Chen, Qian Weng, Wenjie Liao, Binhan Wang, Jiacheng Cao, Xianbin Li, Xiaohuan Guangxi University Key Laboratory of Intelligent Networking and Scenario System School of Information and Communication Guilin University of Electronic Technology Guilin541004 China The College of Computing and Data Science Nanyang Technological University 639798 Singapore School of Architecture and Transportation Engineering Guilin University of Electronic Technology Guilin541004 China National Engineering Laboratory for Comprehensive Transportation Big Data Application Technology Guangxi Nanning530001 China College of Computing and Data Science Nanyang Technological University 639798 Singapore School of Electronic and Information Engineering The Key Laboratory of Advanced Technology of Near Space Information System Ministry of Industry and Information Technology of China Beihang University Beijing100191 China

Unmanned Aerial Vehicles (UAVs) possess high mobility and flexible deployment capabilities, prompting the development of UAVs for various application scenarios within the Internet of Things (IoT). The unique capabilities of UAVs give rise to increasingly critical and complex tasks in uncertain and potentially harsh environments. The substantial amount of data generated from these applications necessitates processing and analysis through deep neural networks (DNNs). However, UAVs encounter challenges due to their limited computing resources when managing DNN models. This paper presents a joint approach that combines multiple-agent reinforcement learning (MARL) and generative diffusion models (GDM) for assigning DNN tasks to a UAV swarm, aimed at reducing latency from task capture to result output. To address these challenges, we first consider the task size of the target area to be inspected and the shortest flying path as optimization constraints, employing a greedy algorithm to resolve the subproblem with a focus on minimizing the UAV’s flying path and the overall system cost. In the second stage, we introduce a novel DNN task assignment algorithm, termed GDM-MADDPG, which utilizes the reverse denoising process of GDM to replace the actor network in multi-agent deep deterministic policy gradient (MADDPG). This approach generates specific DNN task assignment actions based on agents’ observations in a dynamic environment. simulation results indicate that our algorithm performs favorably compared to benchmarks in terms of path planning, Age of Information (AoI), energy consumption, and task load balancing. Copyright © 2024, The Authors. All rights reserved.

关键词： Motion planning

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Experimental study on multi-channel jets in plate assembly under blockage condition

Experimental study on multi-channel jets in plate assembly u...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Huijian, Huang Peng, Wang Dongyang, Li Tan, Sichao Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University Harbin Heilongjiang China

ISBN: (纸本)9780791883785

In the nuclear field, the reactor using plate fuel assembly forms multiple jets at exit. So, it's meaningful to study multiple jets to learn the behavior of the coolant when it leaves the core. This paper uses PIV technology to study the flow characteristics of 9 jets at low Reynolds number. Firstly, the velocity field reveals that the pressure outside the jet is greater than the inside of the jet, which causes the jet to deflect and converge inward at z/w=0-8. Then, the velocity field with different Re number is analyzed in the center plane, and find that the flow distribution is similar. Then, a detailed analysis is performed on the jet under specific conditions, and the merge point is discussed in the paper. At the same time, the first-order velocity tensor are also calculated in this paper. In addition, this article also analyzes the jet flow field after the central narrow channel was blocked. In this experiment, a plug was used to block the No. 5 jet by 1/3. And the flow redistribution is discussed in this case. The methods of flow calculation using PIV technology is established and compared with the real number of flowmeters, it's found that the calculation method is rather accurate. On the other hand, the experiment find that the distribution of flow in each channel is not uniform, and the blocking condition make an increase in the flow of edge channels, which leads to the decreasing of flow in the blocked adjacent channel. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Velocity

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Compliant Assembly of Electrical Connector Based on Contact Search and Force Control with Robotics

Compliant Assembly of Electrical Connector Based on Contact ...

引用

Energy and Electrical Engineering (EEE), International Conference on

作者： Haitao Jing Meng Chen Sihan Wang Ze Zhang Jia Ma Chongfeng Zhang School of Astronautics Nanjing University of Aeronautics and Astronautics Nanjing China Shanghai Key Laboratory of Spacecraft Mechanism Institute of Aerospace System Engineering Shanghai (ASES) Shanghai China Department of Integrated Innovation Institute of Aerospace System Engineering Shanghai (ASES) Shanghai China Shanghai Institute of Space Propulsion Shanghai Academy of Spaceflight Technology (SAST) Shanghai China Science and Technology Committee Shanghai Academy of Spaceflight Technology (SAST) Shanghai China

ISBN: (数字)9798350341768

ISBN: (纸本)9798350341775

The assembly of electrical connectors by space robots is one of the important requirements for in-orbit service. In this paper, aiming at the difficulty of fine assembly of electrical connectors with multi-point coupling contact under the vision-limited conditions, an adaptive assembly method of circular electrical connectors with contact search and robotic force control based on “two-point contact-flexible sliding-attitude correction-alignment and insertion” is proposed. By establishing a dynamic model based on contact and collision, and introducing a force/torque-position hybrid impedance control algorithm, the high reliability assembly of the circular electrical connector is realized by experimental verification, which provides support for the maintenance of the spacecraft.

关键词： Connectors Adaptation models Contacts Heuristic algorithms Dynamics Impedance Collision avoidance Force control Assembly Manipulator dynamics

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Constellation Evaluation Tools for a New Snow Observing Strategy

Constellation Evaluation Tools for a New Snow Observing Stra...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Jaime Bardaji Anam Bayazid Josue I. Tapia Eunsang Cho Carrie Vuyovich Paul T. Grogan School of Systems and Enterprises Stevens Institute of Technology Hoboken NJ Hydrological Sciences Laboratory NASA Goddard Space Flight Center Greenbelt MD Earth System Science Interdisciplinary Center University of Maryland College Park MD

Snow water equivalent (SWE) measurements are crucial for efficiently managing the effects of snow on the environment and human activities. The limitations of providing global snow water equivalent data required to address essential hydrological science questions from existing satellite sensors could potentially be overcome by the emergence of commercial small-satellite platforms, like CubeSats. This research develops a snow observing framework that considers high-resolution observations in critical areas and operational tasking requests from commercial small-satellite platforms by analyzing historical SWE data from the ERA5-Land reanalysis data set. The study finds that going from 4 to 12 satellites in a constellation, not only increases the maximum SWE data observed by 170 mm/hr, but it also does it in a more cost-effective way, increasing the cost only 35%.

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Study on natural circulation flow instabilities in rod bundle channel under rolling condition

Study on natural circulation flow instabilities in rod bundl...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Cheng, Kun Deng, Jian Cai, Rong Qian, Libo Qi, Peiyao Ke, Bingzheng Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University Heilongjiang150001 China

ISBN: (纸本)9780791883785

The effects of rolling condition on the flow instability characteristics of natural circulation (NC) in rod bundle channel were experimentally studied. A 3×3 rod bundle channel is used as the testing section. The experimental system pressure range is 0.2 to 0.6 MPa, and the range of inlet subcooling is 10 to 70°C. The ranges of rolling motion amplitude and period are 10 ∼ 20° and 10 ∼ 30s, respectively. Two typical two-phase flow instabilities in rod bundle channel under rolling condition were found in experiments: (a) the trough-type oscillation caused by the vapor generation at the minimum point of flow fluctuation and (b) the compound oscillation formed by the superposition of the trough-type oscillation and DWOI. Experimental results show that the rolling motion can reduce the threshold heating power of trough-type oscillation and cause the occurrence of NC flow instability in advance. But the rolling motion cannot affect the dimensionless boundary of DWOI in rod bundle channel. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Two phase flow

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Estimating the value of a statistical life in China: A contingent valuation study in six representative cities

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Chinese Journal of Population,Resources and Environment 2023年第4期21卷 269-278页

作者： Chaoji Cao Xinke Song Wenjia Cai Yichao Li Jianhui Cong Xueying Yu Mengzhao Gao Can Wang Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing100084China Center for Healthy Cities Institute for China Sustainable UrbanizationTsinghua UniversityBeijing100084China Tsinghua Urban Institute Tsinghua UniversityBeijing100084China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing100084China Center for Statistical Science Tsinghua UniversityBeijing100084China Department of Industrial Engineering Tsinghua UniversityBeijing100084China School of Economics and Management Shanxi UniversityTaiyuan030000China School of Economics and Management Beihang UniversityBeijing100191China Beijing Advanced Innovation Center for Big Data-based Precision Medicine Beihang UniversityBeijing100191China Key Laboratory of Big Data-Based Precision Medicine(Beihang University) Ministry of Industry and Information TechnologyBeijing100191China

The value of a statistical life(VSL)is a crucial tool for monetizing health *** explore the VSL in China,this study examines people’s willingness to pay(WTP)to reduce death risk from air pollution in six representative cities in China based on face-to-face contingent valuation interviews(n=3936)from March 7,2019 to September 30,*** results reveal that the WTP varied from CNY 455 to 763 in 2019(USD 66-111),corresponding to a VSL range of CNY 3.79-6.36 million(USD 549395-921940).The VSL in China in 2019 is estimated to be CNY 4.76 million(USD 689659).The statistics indicate that monthly expenditure levels,environmental concerns,risk attitudes,and assumed market acceptance,which have seldom been dis‐cussed in previous studies,significantly impact WTP and *** findings will serve as a reference for ana‐lyzing mortality risk reduction benefits in future research and for policymaking.

关键词： Air pollution Contingent valuation method Willingness to pay Value of a statistical life China

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Further investigation on bifurcation and their control of fractional-order bidirectional associative memory neural networks involving four neurons and multiple delays

Further investigation on bifurcation and their control of fr...

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作者： Xu, Changjin Zhang, Wei Aouiti, Chaouki Liu, Zixin Liao, Maoxin Li, Peiluan Guizhou Key Laboratory of Economics System Simulation Guizhou University of Finance and Economics Guiyang China College of Economics and Statistics Guangzhou University Guangzhou China Faculty of Sciences of Bizerta UR13ES47 Research Units of Mathematics and Applications University of Carthage Bizerta Tunisia School of Mathematics and Statistics Guizhou University of Finance and Economics Guiyang China School of Mathematics and Physics University of South China Hengyang China School of Mathematics and Statistics Henan University of Science and Technology Luoyang China

This work principally probes into the stability, the existence, and control of Hopf bifurcation of new established fractional-order delayed bidirectional associative memory (BAM) neural networks with four neurons. Firstly, based on the earlier study, we set up a class of new fractional-order multiple delayed BAM neural networks with four neurons. Secondly, applying an appropriate variable transformation, we get a new equivalent fractional-order single delayed BAM neural networks with four neurons. With the aid of the stability theory and bifurcation knowledge of fractional-order differential dynamical systems, a novel sufficient criterion to guarantee the stability and the appearance of Hopf bifurcation of the addressed fractional-order delayed BAM neural networks is set up. Thirdly, designing a suitable time-delayed feedback controller, the stability region and the time of appearance of Hopf bifurcation for the involved neural networks have been adjusted. Finally, two simulation examples are presented to illustrate the rationality of the mathematical derivation results. The study vindicates that the time delay has great effect on the stability, bifurcation, and its control for involved network models. The obtained fruits of this work can be effectively applied to control and design neural networks. Also, some research ideas will play a key role in studying the related fractional-order dynamical models in actual world. © 2021 John Wiley & Sons, Ltd.

关键词： Hopf bifurcation

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