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Extent and spatial distribution of terrace abandonment in China

Journal of Geographical sciences 2023年第7期33卷 1361-1376页

作者： DONG Shijie XIN Liangjie LI Shengfa XIE Hualin ZHAO Yuluan WANG Xue LI Xiubin SONG Hengfei LU Yahan Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Key Lab of Guangdong for Utilization of Remote Sensing and Geographical Information System/Guangdong Open Laboratory of Geospatial Information Technology and Application Guangzhou Institute of GeographyGuangdong Academy of SciencesGuangzhou 510070China Institute of Ecological Civilization Jiangxi University of Finance and EconomicsNanchang 330013China College of Geography and Environmental Science Guizhou Normal UniversityGuiyang 550001China

Driven by urbanization and industrialization,arable land in hilly and mountainous regions of China is gradually becoming marginalized,with the extent of arable land abandonment rapidly expanding from poor-quality sloping arable land to high-quality *** abandonment of large-scale terraces will lead to a series of socio-economic and ecological effects.A national sample survey was used to investigate the extent and spatial distribution of terrace abandonment in China,and a total of 560 valid village questionnaires from 329 counties were collected in the mountainous areas of *** main findings are as follows:(1)The phenomenon of terrace abandonment was widespread throughout the country,with 54% of the total surveyed villages exhibiting terrace abandonment,and the area of abandoned terraces accounting for 9.79% of the total.(2) The degree of terrace abandonment is high in the south and low in the *** most serious region with abandonment was the hilly and mountainous areas in the south,especially in the middle and lower Yangtze River region.(3)The main driving factors of terrace abandonment were rural labor migration,agricultural mechanization level,irrigation conditions,and transportation conditions for *** measures should be taken based on the specific conditions of each area to alleviate terrace *** such as improving terrace mechanization are universally ***,low-quality terraces can be withdrawn orderly,and for high-quality terraces,multiple measures are needed to consolidate agricultural production,such as adjusting the planting structure,strengthening agricultural infrastructure construction,and encouraging the transfer of land-use rights as well as large-scale operation.

关键词： terraces arable land abandonment national sample survey spatial variation China

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A MULTI-AGENT JAMMING DECISION-MAKING METHOD BASED ON SP-HASAC

A MULTI-AGENT JAMMING DECISION-MAKING METHOD BASED ON SP-HAS...

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IET International Radar Conference 2023, IRC 2023

作者： Gao, Jingpeng Shen, Chen Gao, Lu Jiang, Zhiye College of Information and Communication Engineering Harbin Engineering University Harbin China Beijing Institute of Electronic System Engineering Beijing China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

ISBN: (纸本)9781839539954

In the study of the multi-UAV penetration mission decision method, the Heterogeneous Agent Soft Actor-Critic algorithm uses the HAML framework and the maximum entropy principle to enable UAVs to have stronger anti-jamming capability and exploration capability. However, it is difficult to accurately evaluate the action value of UAVs and the training stability is poor. To address this issue, this paper proposes a multi-agent based on the state prediction-HASAC(SP-HASAC) jamming decision method. Based on the idea of advantage function decomposition and environmental dynamics model, the state prediction network is designed to extract more abundant spatial information of penetration battlefield and achieve accurate evaluation of the action value of multi-UAV. Combining with the negative domain activation theory, the ReLU function is improved to realize the stable training of multi-UAV. The simulation results show that in the electronic penetration scenario of three UAVs against a single radar, the training convergence time of the proposed improved algorithm is reduced by 22% compared with the original algorithm. Three UAVs penetration to twice the burn-through distance still has more than 70% penetration success rate. © The Institution of Engineering & technology 2023.

关键词： Jamming

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Big-data-driven vessel destination prediction for smart port management

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Engineering Applications of Artificial Intelligence 2025年 154卷

作者： Chen, Jin Zhang, Qiang Liang, Maohan Peng, Chang Chen, Chen Sanya Institute Hunan University of Science and Technology China National Key Laboratory of Space Integrated Information System China Hubei Key Laboratory of Inland Shipping Technology School of Navigation Wuhan University of Technology China Department of Civil and Environmental Engineering National University of Singapore Singapore College of Computer Science and Electronic Engineering Hunan University China

The accurate prediction of vessel destinations is crucial for enhancing maritime traffic efficiency, optimizing port management, and improving regional economic analysis. However, destination information in Automatic Identification system (AIS) data is often missing or inaccurate, which undermines the reliability of maritime analytic. Traditional vessel destination prediction methods primarily focus on measuring trajectory similarities, which results in high computational complexity. This study develops a deep learning approach to vessel destination prediction by transforming the problem into an image classification task. Rasterized images of historical destination ports and vessel trajectories are generated, incorporating AIS data within a fixed spatial context. A multi-scale residual convolutional network is constructed to extract relevant trajectory and port distribution features. To enhance the representation of trajectory endpoints, which are critical for predicting the destination port, a multi-attention mechanism is introduced. This mechanism increases the learning weight assigned to endpoint features, improving prediction accuracy. Finally, a classification network predicts the destination port based on the extracted features. The performance of the proposed method is evaluated using AIS data from the Denmark Strait. Experimental results demonstrate that the model outperforms existing methods, highlighting its potential for applications in smart port management and maritime traffic optimization. © 2025 Elsevier Ltd

关键词： Waterway transportation

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Design and Experimental Validation of Sealing Assembly for Lunar Regolith Volatile Extraction Heating Furnace

Design and Experimental Validation of Sealing Assembly for L...

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2023 IEEE International Conference on Robotics and Biomimetics, ROBIO 2023

作者： Zhang, Hongan Tang, Junyue Wang, Yinchao Lu, Zixiao Wang, Bo Cao, Miaoyan Jiang, Shengyuan Yanshan University Mechanical Engineering Qinhuangdao China Harbin Institute of Technology State Key Laboratory of Robotics and System Harbin China Shenyang Aerospace University Mechatronics Institute Shenyang China Chinese Academy of Science National Center for Nanoscience and Technlogy Beijing China China Academy of Space Technology Beijing China

ISBN: (纸本)9798350325706

A lunar regolith in-situ analysis payload deploying a mass spectrometer is proposed to exactly detect the water ice of the South Pole of the moon for China future lunar exploration missions. In order to realize the goal, an airtight heating furnace for volatile extraction from lunar regolith is desired. In this paper, sealing methods for lunar regolith volatile in heating furnace to future proposed in-situ sampling and analysis of lunar samples were investigated based on power requirements, furnace closing accuracy requirements, dust tolerance and operation in the Lunar environment. Methods implemented include a balanced metal hollow ring seal, a double channel ferrule tab ring radial seal and a spring energized seal. Comparing the performance of sealing methods under the above conditions, a spring energized seal is selected as the heating furnace seal. The materials and structure of the seal are designed based on the rigidity requirements, leakage rate requirements and working environment requirements. In order to test the sealing performance of seals after repeated sealing in high and low temperature environments, a seal leak detection system was designed. The test results indicate that the seal can meet the sealing performance requirements after repeated sealing at various temperatures. © 2023 IEEE.

关键词： Dust tolerance Leakage rate Lunar environment Repeated sealing Spring energized seal

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Temperature fluctuations and heat transport in partitioned supergravitational thermal turbulence

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Acta Mechanica Sinica 2024年第6期40卷 20-30页

作者： Dongpu Wang Jing Liu Rushi Lai Chao Sun Beijing Key Laboratory of Space Thermal Control Technology Beijing Institute of Spacecraft System EngineeringBeijing100094China Center for Combustion Energy Key Laboratory for Thermal Science and Power Engineering of MoEand Department of Energy and Power EngineeringTsinghua UniversityBeijing100084China Department of Engineering Mechanics School ofAerospace EngineeringTsinghua UniversityBeijing100084China

We report an experimental study of the local temperature fluctuationsδT and heat transport in a partitioned supergravitational turbulent convection *** to the dynamics of zonal flow in the normal system without partition walls,the probability density function(PDF)at a position in the mixing zone exhibits a downward bending shape,suggesting that the multi-plume clustering effect plays an important *** partitioned system,zonal flow is suppressed and the PDFs indicate that the single-plume effect is ***,statistical analysis shows that the PDF ofδT is sensitive to ***,the thermal spectra follow P(f)∼f^(-5) in the normal system,which is relevant to the zonal *** absolute value of the scaling exponent of P(f)and the scaling range become small in the partitioned system,which provides another evidence for the influence of zonal flow on the energy ***,heat transfer enhancement is found in the partitioned system,which may result from zonal flow being restricted and then facilitating the radial movement of thermal plumes to the opposite conducting *** work may provide insights into the flow and heat transport control of some engineering and geophysical flows.

关键词： Partitioned turbulent convection Supergravity Probability density function Power spectra Heat transfer

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利用等效梁模型对大型空间天线桁架结构进行主动控制

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Acta Mechanica Sinica 2023年第6期39卷 153-165页

作者：史江刘翔蔡国平吕亮亮房光强尤超蓝姚赛金 Department of Engineering Mechanics MOE Key Laboratory of HydrodynamicsShanghai Jiao Tong UniversityShanghai 200240China Space Structure and Mechanism Technology Laboratory of China Aerospace Science and Technology Group Co.Ltd. Shanghai Institute of Aerospace System EngineeringShanghai 200240China Shanghai Institute of Satellite Engineering Shanghai 201109China

本文提出了一种等效力方法,以解决难以利用等效梁模型对原桁架结构进行控制设计的问题.通过等效梁模型的控制设计得到原桁架结构中执行器的控制力,使得原桁架结构的振动得到控制.通过数值模拟算例表明,作用在等效模型上的控制力与作用... 详细信息

本文提出了一种等效力方法,以解决难以利用等效梁模型对原桁架结构进行控制设计的问题.通过等效梁模型的控制设计得到原桁架结构中执行器的控制力,使得原桁架结构的振动得到控制.通过数值模拟算例表明,作用在等效模型上的控制力与作用在原桁架结构上的力不同,进一步证明了所提方法的必要性和有效性.本文研究为大型空间桁架结构的动力学分析与主动控制设计提供了新途径.

关键词：桁架结构等效梁主动控制等效模型控制力执行器动力学分析模拟算例

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The dynamic compressive properties of magnetorheological plastomers: enhanced magnetic-induced stresses by non-magnetic particles

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Journal of Materials science & technology 2022年第7期102卷 195-203页

作者： Haoming Pang Zhenbang Xu Longjiang Shen Jun Li Junshuo Zhang Zhiyuan Li Shouhu Xuan Xinglong Gong CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsCAS Center for Excellence in Complex System MechanicsUniversity of Science and Technology of China(USTC)Hefei 230027China Anhui Weiwei Rubber Parts Group Co.Ltd Tongcheng 231400China CAS Key Laboratory of On-orbit Manufacturing and Integration for Space Optics System Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Hunan Bogie Engineering Research Center Zhuzhou 412000China

In this research, a series of hollow glass powder(HGP) reinforced magnetorheological plastomers(MRPs)were prepared to improve the impact resistance of the materials, and the dynamic compressive properties of MRPs under high strain rate were investigated by using a split Hopkinson pressure bar(SHPB)system equipped with a customized magnetic device. Experimental results showed the HGPs greatly enhanced the yield stresses of the MRPs. Especially, for MRPs with 9 vol.% carbonyl iron powders(CIPs), the magnetic-induced yield stress increased from 7.3 MPa to 17.1 MPa(134% increased) by adding 18 vol.%HGPs. The particle structures in MRPs were further simulated and the corresponding intergranular stress was calculated to study the enhancement effect of HGPs. The simulated results showed that more compact structures were formed with the excluded volume caused by secondary HGPs, so the yield stresses of the MRPs increased under a magnetic field. However, when the mass ratio of HGP to CIP was larger than 0.67, HGPs would hinder the formation of chain-like structures and reduce the magneto-mechanical properties. As a result, the replacing of CIPs by HGPs was proven to be an excellent strategy to improve the dynamic properties of MRPs.

关键词： Particle-reinforced composites Stress/strain curves Microstructures Impact behavior Mechanical properties

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A LSTM-based method for simulation execution validity evaluation 33

A LSTM-based method for simulation execution validity evalua...

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33rd European Modeling and simulation Symposium, EMSS 2021

作者： Wang, YuLun Li, Wei Li, Jing Control and Simulation Center Harbin Institute of Technology Harbin150080 China Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory Beijing100074 China

This paper improves the concept of simulation execution validity and a methodology to assess the complex simulation system. As the complexity of the simulation system gradually rises, the magnitude of the simulation data obtained continues to increase, which makes it extremely difficult for experts to provide expert knowledge to evaluate the execution validity of the simulation system. More precisely, the essence of execution validity is to dig out the hidden relationships in the simulation time series data and complete the classification task whether it is valid. Considering that machine learning can better complete the two tasks of mining data features and classification, this paper adopts long short-term memory, a neural network used to process time series data, to evaluate the execution validity. Finally, an experiment is conducted on a simulation system, and the results show that the evaluation method based on LSTM can accurately evaluate the validity of the simulation system, and can greatly improve the efficiency of evaluation. © 2021 The Authors.

关键词： Long short-term memory

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Cooperative jamming resource allocation based on integer-encoded directed mutation artificial bee colony algorithm 4

Cooperative jamming resource allocation based on integer-enc...

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4th IEEE International Conference on Electronic Information and Communication technology, ICEICT 2021

作者： Xia, Jiechen Ma, Jing Li, Yibing Song, Mingzhao Harbin Engineering University Harbin150001 China Key Laboratory of Advanced Marine Communication and Information Technology Ministry of Industry and Information Technology Science and Technology on Special System Simulation Laboratory Beijing100854 China

ISBN: (纸本)9781665432030

Electromagnetic countermeasure (ECM) is of extreme importance in modern warfare. In order to confront the threat of radar-net, cooperative jamming platform with multiple jammers is the main approach. A proper allocation of jamming resource is required before and during the process of interference. This paper proposes an artificial bee colony (ABC) based jamming resource allocation (JRA) algorithm with few parameter adjustments. The allocation strategy is encoded in integer to better handle the constraints of JRA problem. Furthermore, a genetic algorithm (GA) inspired solution update method is introduced in stages of algorithm to accelerate the convergence rate. simulation result shows that the proposed algorithm has a better performance in both rate and precision of convergence compared with tabu search artificial bee colony algorithm (TSABC) and ant colony optimization algorithm (ACO), which were adopted in previous related studies. ©2021 IEEE

关键词： Tabu search

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A Jamming Decision-Making Method Based on Next State Prediction SAC 6

A Jamming Decision-Making Method Based on Next State Predict...

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6th IEEE International Conference on Electronic Information and Communication technology, ICEICT 2023

作者： Chen, Geng Gao, Jingpeng Zhang, Tianran Jiang, Zhiye Shen, Chen College of Information and Communication Engineering Harbin Engineering University Harbin China Beijing Institute of Electronic System Engineering Beijing100854 China Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

ISBN: (纸本)9798350399059

In light of the growing complexity of the electromagnetic environment, traditional jamming decision-making methods have become less effective due to poor generalization and inefficient jamming performance. This paper proposes a jamming decision-making method based on next state prediction SAC (Soft Actor-Critic) to address this issue. Firstly, we design the state, action, and reward elements under electronic warfare scenarios. Secondly, a next state prediction critic network is proposed to accurately estimate the value function by modeling the environment dynamics and extracting richer representational information. Finally, a negative activation ReLU is introduced to improve the utilization ratio of network parameters. simulation results show that the proposed method achieves a 98.4% success rate at a distance of 90 km from the radar and a 70.0% success rate at 30 km. Therefore, this method exhibits good adaptability and jamming performance in the field of jamming decision-making. © 2023 IEEE.

关键词： Decision making

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