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Tactical conflict resolution in urban airspace for unmanned aerial vehicles operations using attention-based deep reinforcement learning

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Green Energy and Intelligent Transportation 2023年第4期2卷 43-57页

作者： Mingcheng Zhang Chao Yan Wei Dai xiaojia xiang Kin Huat Low School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore College of Intelligence Science and Technology National University of Defense TechnologyChangsha 410073China Air Traffic Management Research Institute Nanyang Technological UniversitySingapore 637460Singapore

Unmanned aerial vehicles(UAVs)have gained much attention from academic and industrial areas due to the significant number of potential applications in urban airspace.A traffic management system for these UAVs is needed to manage this future *** conflict resolution for unmanned aerial systems(UASs)is an essential piece of the puzzle for the future UAS Traffic Management(UTM),especially in very low-level(VLL)urban *** conflict resolution in higher altitude airspace,the dense high-rise buildings are an essential source of potential conflict to be considered in VLL urban *** this paper,we propose an attention-based deep reinforcement learning approach to solve the tactical conflict resolution ***,we formulate this task as a sequential decision-making problem using Markov Decision Process(MDP).The double deep Q network(DDQN)framework is used as a learning framework for the host drone to learn to output conflict-free maneuvers at each time *** use the attention mechanism to model the individual neighbor's effect on the host drone,endowing the learned conflict resolution policy to be adapted to an arbitrary number of neighboring ***,we build a simulation environment with various scenarios covering different types of encounters to evaluate the proposed *** simulation results demonstrate that our proposed algorithm provides a reliable solution to minimize secondary conflict counts compared to learning and non-learning-based approaches under different traffic density scenarios.

关键词： Unmanned aircraft system traffic management Tactical conflict resolution Double deep Q network Attention mechanism Secondary conflict

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Boosting bulk charge transport of CuWO_(4) photoanodes via Cs doping for solar water oxidation

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Chinese Journal of Structural Chemistry 2024年第2期43卷 31-37页

作者： Xinyi Fan xiaojia Yuan Kan Zhang School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing210094China

Copper tungstate(CuWO_(4))is a promising photoanode for photoelectrochemical(PEC)water splitting due to its appropriate energy band position and broad light absorption ***,the inherent unfilled 3d atomic orbital of Cu acts as a natural electron-hole recombination site,significantly constraining the PEC performance of CuWO_(4).Herein,Cs atoms with complete atomic orbitals are doped into CuWO_(4)in order to obtain better bulk charge separation *** a result,the photocurrent of Cs@CuWO_(4)increases from 0.57 to 0.99 mA cm^(-2)compared to CuWO_(4)at 1.23 V *** hydrogen electrode(RHE)under AM 1.5G illumination,as well as the bulk charge transfer efficiencies rising from 13.5%to 19.3%.In addition,density of states(DOS)calculations further prove that the introduction of Cs atoms effectively suppresses the contribution of Cu 3d orbitals at the Fermi *** work offers a valuable reference for the advancement of CuWO_(4)as the next-generation PEC photoanode material.

关键词： Photoanode Water splitting Photoelectrochemical Charge separation

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基于深度强化学习的固定翼无人机编队协调控制方法

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航空学报 2021年第4期42卷 414-427页

作者：相晓嘉闫超王菖尹栋国防科技大学智能科学学院长沙410073

由于运动学的复杂性和环境的动态性,控制一组无人机遂行任务目前仍面临较大挑战。首先,以固定翼无人机为研究对象,考虑复杂动态环境的随机性和不确定性,提出了基于无模型深度强化学习的无人机编队协调控制方法。然后,为平衡探索和利用,... 详细信息

由于运动学的复杂性和环境的动态性,控制一组无人机遂行任务目前仍面临较大挑战。首先,以固定翼无人机为研究对象,考虑复杂动态环境的随机性和不确定性,提出了基于无模型深度强化学习的无人机编队协调控制方法。然后,为平衡探索和利用,将ε-greedy策略与模仿策略相结合,提出了ε-imitation动作选择策略;结合双重Q学习和竞争架构对DQN(Deep Q-Network)算法进行改进,提出了ID3QN(Imitative Dueling Double Deep Q-Network)算法以提高算法的学习效率。最后,构建高保真半实物仿真系统进行硬件在环仿真飞行实验,验证了所提算法的适应性和实用性。

关键词：固定翼无人机无人机编队协调控制深度强化学习神经网络

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面向城市环境的巡飞弹控制站沉浸式显示技术

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战术导弹技术 2022年第6期 63-72页

作者：谭沁相晓嘉国防科技大学智能科学学院长沙410073

在近期如俄乌冲突等多起局部战争中,巡飞弹发挥出了机动灵活、精准打击等战场优势,受到越来越多的关注,但在城市环境中使用巡飞弹,易受到各种各样建筑物的阻挡,影响操作员对战场的研判和对巡飞弹的精准控制。为使操作员快速掌握大规模... 详细信息

在近期如俄乌冲突等多起局部战争中,巡飞弹发挥出了机动灵活、精准打击等战场优势,受到越来越多的关注,但在城市环境中使用巡飞弹,易受到各种各样建筑物的阻挡,影响操作员对战场的研判和对巡飞弹的精准控制。为使操作员快速掌握大规模复杂城市作战场景中的任务环境,辅助操作员高效指挥巡飞弹,从提高操作员态势感知能力的方向对巡飞弹控制站展开研究,设计了一种基于三维动态场景重构和虚拟现实的控制站系统态势显示方法,基于OpenSceneGraph(OSG)开源可视化引擎,采用四叉树管理、金字塔结构的PageLOD动态加载方法,进行巡飞弹任务场景要素管理及建模显示;基于无限串流虚拟现实渲染技术,构建了沉浸式控制站验证系统;设计巡飞弹引导控制试验,通过对任务完成时间及碰撞次数进行客观测试、统计问卷调查表进行主观分析,并对比有无沉浸式的试验效果,验证了该方法易于学习使用且有效提高了操作员的态势感知能力。

关键词：巡飞弹沉浸式显示三维场景重构虚拟现实渲染技术系统构建

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Impact of Osmotic Pressure on Seepage in Shale Oil Reservoirs

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Fluid Dynamics & Materials Processing 2024年第6期20卷 1365-1379页

作者： Lijun Mu xiaojia Xue Jie Bai Xiaoyan Li Xueliang Han Oil and Gas Technology Research Institute PetroChina Changqing Oilfield CompanyXi’an710018China

Following large-scale volume fracturing in shale oil reservoirs,well shut-in measures are generally *** tests and field trials have underscored the efficacy of fracturing fluid imbibition during the shut-in phase in augmenting shale oil *** conventional reservoirs,shale oil reservoirs exhibit characteristics such as low porosity,low permeability,and rich content of organic matter and clay ***,the osmotic pressure effects occurring between high-salinity formation water and low-salinity fracturing fluids are *** current understanding of the mobilization patterns of crude oil in micro-pores during the imbibition process remains nebulous,and the mechanisms underpinning osmotic pressure effects are not fully *** study introduces a theoretical approach,by which a salt ion migration control equation is derived and a mathematical model for spontaneous imbibition in shale is introduced,which is able to account for both capillary and osmotic *** indicate that during the spontaneous imbibition of low-salinity fluids,osmotic effects facilitate the migration of external fluids into shale pores,thereby complementing capillary forces in displacing shale *** considering both capillary and osmotic pressures,the calculated imbibition depth increases by 12%compared to the case where only capillary forces are *** salinity difference between the reservoir and the fracturing fluids significantly influences the imbibition *** for the shutin phase reveal that the pressure between the matrix and fractures reaches a dynamic equilibrium after 28 days of *** the production phase,the maximum seepage distance in the target block is approximately 6.02 m.

关键词： Shale oil osmotic pressure numerical simulation effective seepage distance

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Circular RNAs in breast cancer diagnosis,treatment and prognosis

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Oncology Research 2024年第2期32卷 241-249页

作者： xiaojia HUANG CAILU SONG JINHUI ZHANG LEWEI ZHU HAILIN TANG Department of Breast Oncology Surgery Affiliated Cancer Hospital&Institute of Guangzhou Medical UniversityGuangzhou510095China State Key Laboratory of Oncology in South China Guangdong Provincial Clinical Research Center for CancerSun Yat-sen University Cancer CenterGuangzhou510060China Department of Breast Surgery The First People’s Hospital of FoshanFoshan528000China

Breast cancer has surpassed lung cancer to become the most common malignancy *** incidence rate and mortality rate of breast cancer continue to rise,which leads to a great burden on public *** RNAs(circRNAs),a new class of noncoding RNAs(ncRNAs),have been recognized as important oncogenes or suppressors in regulating cancer initiation and *** breast cancer,circRNAs have significant roles in tumorigenesis,recurrence and multidrug resistance that are mediated by various ***,circRNAs may serve as promising targets of therapeutic strategies for breast cancer *** study reviews the most recent studies about the biosynthesis and characteristics of circRNAs in diagnosis,treatment and prognosis evaluation,as well as the value of circRNAs in clinical applications as biomarkers or therapeutic targets in breast *** the mechanisms by which circRNAs function could help transform basic research into clinical applications and facilitate the development of novel circRNA-based therapeutic strategies for breast cancer treatment.

关键词： CircRNA Breast cancer Diagnosis Treatment Biomarker

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一种策略灵活的多版本文件系统的设计与实现

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高技术通讯 2008年第6期18卷 590-595页

作者：郝子江向小佳田金兰清华大学计算机系北京100084

设计并实现了一种新型的多版本文件系统——HFS。HFS 把启发式规则和用户规则结合起来,提供灵活的版本保留策略,为必要的文件保留必要的版本,节省了存储空间。同时,还通过写时复制和目录版本等技术,进一步降低对存储资源的消耗。分析表... 详细信息

设计并实现了一种新型的多版本文件系统——HFS。HFS 把启发式规则和用户规则结合起来,提供灵活的版本保留策略,为必要的文件保留必要的版本,节省了存储空间。同时,还通过写时复制和目录版本等技术,进一步降低对存储资源的消耗。分析表明,该系统可以在保证数据可靠性的同时,有效地提高存储资源的利用率。HFS 的实现基于 Ext3,对 HFS 和 Ext3的文件读写性能的测试和比较的结果表明,HFS 的顺序读文件的性能与 Ext3相当,顺序写文件的性能和随机读写的性能比 Ext3降低了2%～5%,版本机制对文件系统性能的影响很小。

关键词：多版本文件系统版本保留策略写时复制目录版本

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Highly selective extraction of aromatics from aliphatics by using metal chloride-based ionic liquids

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Chinese Journal of Chemical Engineering 2024年第1期65卷 222-229页

作者： Hui Yu xiaojia Wu Chuanqi Geng Xinyu Li Chencan Du Zhiyong Zhou Zhongqi Ren State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China

The separation of aromatics from aliphatics is essential for achieving maximum exploitation of oil resources in the petrochemical *** this study,a series of metal chloride-based ionic liquids were prepared and their performances in the separation of 1,2,3,4-tetrahydronaphthalene(tetralin)/dodecane and tetralin/decalin systems were *** these ionic liquids,1-ethyl-3-methylimidazolium tetrachloroferrate([EMIM][FeCl_(4)])with the highest selectivity was used as the *** functional theory calculations showed that[EMIM][FeCl_(4)]interacted more strongly with tetralin than with dodecane and *** decomposition analysis of[EMIM][FeCl_(4)]-tetralin indicated that electrostatics and dispersion played essential roles,and induction cannot be *** van der Waals forces was a main effect in[EMIM][FeCl_(4)]-tetralin by independent gradient model *** tetralin distribution coefficient and selectivity were 0.8 and 110,respectively,with 10%(mol)tetralin in the initial tetralin/dodecane system,and 0.67 and 19.5,respectively,with 10%(mol)tetralin in the initial tetralin/decalin *** selectivity increased with decreasing alkyl chain length of the *** influence of the extraction temperature,extractant dosage,and initial concentrations of the system components on the separation performance were *** experiments showed that the regenerated[EMIM][FeCl_(4)]could be used repeatedly.

关键词： Ionic liquid Aromatic hydrocarbon Aliphatic hydrocarbon Extraction

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Stress-assisted corrosion mechanism of 3Ni steel by using gradient boosting decision tree machining learning method

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1311-1321页

作者： xiaojia Yang Jinghuan Jia Qing Li Renzheng Zhu Jike Yang Zhiyong Liu Xuequn Cheng Xiaogang Li Institute of Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China AECC Key Laboratory of Advanced Corrosion and Protection of Aeronautical Materials AECC Beijing Institute of Aeronautical MaterialsBeijing 100095China Shunde Innovation School University of Science and Technology BeijingFoshan 528399China

Traditional 3Ni weathering steel cannot completely meet the requirements for offshore engineering development,resulting in the design of novel 3Ni steel with the addition of microalloy elements such as Mn or Nb for strength enhancement becoming a *** stress-assisted corrosion behavior of a novel designed high-strength 3Ni steel was investigated in the current study using the corrosion big data *** information on the corrosion process was recorded using the galvanic corrosion current monitoring *** gradi-ent boosting decision tree(GBDT)machine learning method was used to mine the corrosion mechanism,and the importance of the struc-ture factor was *** exposure tests were conducted to verify the calculated results using the GBDT *** indic-ated that the GBDT method can be effectively used to study the influence of structural factors on the corrosion process of 3Ni ***-ferent mechanisms for the addition of Mn and Cu to the stress-assisted corrosion of 3Ni steel suggested that Mn and Cu have no obvious effect on the corrosion rate of non-stressed 3Ni steel during the early stage of *** the corrosion reached a stable state,the in-crease in Mn element content increased the corrosion rate of 3Ni steel,while Cu reduced this *** the presence of stress,the increase in Mn element content and Cu addition can inhibit the corrosion *** corrosion law of outdoor-exposed 3Ni steel is consistent with the law based on corrosion big data technology,verifying the reliability of the big data evaluation method and data prediction model selection.

关键词： weathering steel stress-assisted corrosion gradient boosting decision tree machining learning

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基于微分几何与李群的无人机编队会合方法

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国防科技大学学报 2013年第6期35卷 157-164页

作者：李杰彭双春安宏雷相晓嘉沈林成国防科技大学机电工程与自动化学院湖南长沙410073 国防科技大学航天科学与工程学院湖南长沙410073

在领航-跟随编队模式下,设计了一种基于追缉策略的无人机编队会合方法。基于微分几何曲线论和弗雷涅-塞雷标架建立了无人机非解耦三维运动模型,其中将曲率和挠率作为控制量;结合该模型给出了无人机三维编队会合问题的数学描述,它将导弹... 详细信息

在领航-跟随编队模式下,设计了一种基于追缉策略的无人机编队会合方法。基于微分几何曲线论和弗雷涅-塞雷标架建立了无人机非解耦三维运动模型,其中将曲率和挠率作为控制量;结合该模型给出了无人机三维编队会合问题的数学描述,它将导弹制导问题中的终端落角约束映射为编队会合问题中僚机的航迹倾角约束,同时引入额外的航迹方位角约束;使用特殊正交群的元素来度量长僚机方向偏差,并通过局部坐标映射将其映射为对应李代数空间中的旋量;基于该旋量设计了编队会合几何导引律,并给出相应的曲率和挠率控制指令;分别在长机稳定平飞和转弯机动条件下进行了多机编队会合数字仿真实验,仿真结果显示僚机能够有效地跟踪长机航向并收敛至指定位形,说明了方法的有效性。

关键词：无人机编队会合微分几何李群几何控制

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