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Robust Control for Static Loading of Electro-hydraulic Load Simulator with Friction Compensation

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Chinese Journal of Aeronautics 2012年第6期25卷 954-962页

作者： yao Jianyong JIAO Zongxia yao Bin School of Mechanical Engineering Nanjing University of Science and Technology Nanjing 210094 China Science and Technology on Aircraft Control Laboratory Beihang University Beijing 100191 China School of Mechanical Engineering Purdue University West Lafayette IN 47907 USA

Load simulator is a key test equipment for aircraft actuation systems in hardware-in-the-loop-simulation. Static loading is an essential function of the load simulator and widely used in the static/dynamic stiffness test of aircraft actuation systems. The tracking performance of the static loading is studied in this paper. Firstly, the nonlinear mathematical models of the hydraulic load simulator are derived, and the feedback linearization method is employed to construct a feed-forward controller to improve the force tracking performance. Considering the effect of the friction, a LuGre model based friction compensation is synthesized, in which the unmeasurable state is estimated by a dual state observer via a controlled learning mechanism to guarantee that the estimation is bounded. The modeling errors are attenuated by a well-designed robust controller with a control accuracy measured by a design parameter. Employing the dual state observer is to capture the different effects of the unmeasured state and hence can improve the friction compensation accuracy. The tracking performance is summarized by a derived theorem. Experimental results are also obtained to verify the high performance nature of the proposed control strategy.

关键词： electro-hydraulic load simulator robust control friction compensation feedback linearization LuGre model nonlinear control state estimation

Sheaves on non-reduced curves in a projective surface

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Science China Mathematics 2023年第2期66卷 237-250页

作者： yao Yuan Beijing National Center for Applied Mathematics Academy for Multidisciplinary StudiesCapital Normal UniversityBeijing 100048China

Sheaves on non-reduced curves can appear in moduli spaces of 1-dimensional semistable sheaves over a surface and moduli spaces of Higgs bundles as *** estimate the dimension of the stack M_(X)(nC,χ)of pure sheaves supported at the non-reduced curve nC(n≥2)with C an integral curve on *** prove that the Hilbert-Chow morphism h_(L,χ):M_(X)^(H)(L,χ)→|L|sending each semistable 1-dimensional sheaf to its support has all its fibers of the same dimension for X Fano or with the trivial canonical line bundle and|L|contains integral curves.

关键词： 1-dimensional pure sheaves on projective surfaces Hilbert-Chow morphism Hitchin fibration stack

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A systematic framework to understand central bank digital currency

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Science China(Information Sciences) 2018年第3期61卷 206-213页

作者： Qian yao Institute of Digital Money of the People’s Bank of China

The ongoing research and development of digital fiat currency(DFC) have triggered attention of policy makers, regulators and the industrial and academic communities. But there is not yet a clear idea and blueprint of what DFC looks like. This paper establishes a systematic framework to analyze the essence and connotation of DFC from four dimensions: currency value, technical aspects, means of implementation and application scenarios. It is argued that DFC is a credit-based currency in terms of value, a crypto-currency from a technical perspective, an algorithm-based currency in terms of implementation and a smart currency in application scenarios. Compared with existing private digital currencies and electronic currencies, DFC will be equipped with brand new and higher qualities. The goal of Chinese DFC is to contribute to more stable value, more secure data, more powerful regulation, stronger empowerment of individuals in payment activities and smarter application. Chinese DFC should have qualities that enable it to provide better service for the public, to offer effective tools for macroeconomic control and to lay a solid foundation for Reg Tech development.

关键词： digital fiat currency credit-based currency crypto-currency algorithm-based currency smart currency central bank digital currency

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CARFB:即插即用的目标检测模块

计算机科学与探索 2025年第1期19卷 223-236页

作者：杨梅君姚若侠谢娟英陕西师范大学计算机科学学院西安710119

针对坐标注意力(CA)在水平和垂直方向特征的平均池化可能丢失目标显著特征,以及使用二维普通卷积对小目标特征学习不足的情况,提出了CARFB(coordinate attention and receptive field block)模块。该模块将CA的平均池化修改为平均+最大... 详细信息

针对坐标注意力(CA)在水平和垂直方向特征的平均池化可能丢失目标显著特征,以及使用二维普通卷积对小目标特征学习不足的情况,提出了CARFB(coordinate attention and receptive field block)模块。该模块将CA的平均池化修改为平均+最大池化,以保留输入特征在水平和垂直方向的显著和细节信息;利用RFB具有不同大小感受野的优势,在水平和垂直方向分别使用RFB模块代替CA的融合特征统一卷积,以同时提取不同大小目标的特征;引入包含不同大小卷积核和步长的CBS模块,替换CA的二维普通卷积,进一步提取水平和垂直方向的特征,得到重新加权的输出特征。CARFB模块在水平和垂直方向保存目标位置信息,利用不同感受野提取不同大小目标的强辨别性特征,从而具有更强的特征学习能力。为了验证提出的即插即用模块CARFB的性能,将其嵌入ObjectBox目标检测框架,得到ObjectBox-CARFB模型;用CARFB模块替换RFBnet中的RFB模块,得到CARFBnet目标检测模型。MSCOCO数据集的实验测试表明,ObjectBox-CARFB模型的性能得到全面提升,尤其对小目标的检测性能提升突出;PASCALVOC和MSCOCO数据集的实验结果表明,CARFBnet300和CARFBnet512的目标检测能力分别优于原始RFBnet300和RFBnet512模型,并优于其他同系列对比模型。提出的CARFB模块具有更强的特征学习能力,对不同尺度目标均能取得较好的检测效果,特别是在小目标检测方面,效果提升显著。提出的CARFB模块可以嵌入到任何一个卷积神经网络,能保存更多的目标信息,具有更强的特征学习能力和更高的网络性能,对不同尺度目标均能取得较好的检测效果,尤其对小目标的检测效果提升显著。

关键词：目标检测感受野模块(RFB) 坐标注意力小目标深度学习

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异构无人系统协同控制研究进展

工程科学学报 2025年第1期47卷 66-78页

作者：郭兴李擎姚其家鲁小雅北京科技大学自动化学院北京100083 工业过程知识自动化教育部重点实验室北京100083

面对复杂化、多样化和立体化的任务需求,异构无人系统将空、地、海跨域优势互补,最大化提升系统各方面能力,为未来协同作战和智慧民生提供有力的技术保障.首先,梳理了国内外在跨域协同领域出台的推动性文件,介绍了异构无人系统在军用、... 详细信息

面对复杂化、多样化和立体化的任务需求,异构无人系统将空、地、海跨域优势互补,最大化提升系统各方面能力,为未来协同作战和智慧民生提供有力的技术保障.首先,梳理了国内外在跨域协同领域出台的推动性文件,介绍了异构无人系统在军用、科研院所和民用等三方面的实际应用.其次,针对异构无人系统关键技术之一的协同控制,分别阐述了异构无人系统协同控制在一致性、轨迹跟踪和编队‒合围等三方面的最新进展.此外,还特别讨论了在不同通信条件下协同控制所面临的挑战和解决方案.其中,由于一致性和轨迹跟踪存在上层控制理论性和下层控制可行性的区别,进一步从滑模控制、自适应控制、反步控制和自适应动态规划等四方面对轨迹跟踪研究展开阐述.然后,为了更好地促进异构无人系统协同控制在实际中的应用,通过总结前人相关工作,讨论了其在多约束控制与实时性、多任务切换控制和跨域通信下稳定性等三方面亟需解决的技术瓶颈.最后,综合异构无人系统协同控制研究现状和实际需求来看,指出了其在深度强化学习与分布式博弈、人机交互以及反群体智能等三方面的发展趋势.

关键词：异构无人系统协同控制跨域协同任务需求技术瓶颈

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WAVEFORM RELAXATION METHODS OF NONLINEAR INTEGRAL-DIFFERENTIAL-ALGEBRAIC EQUATIONS

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Journal of Computational Mathematics 2005年第1期23卷 49-66页

作者： yao-linJiang DepartmentofMathematicalSciences Xi'anJiaotongUniversityXi'an710049China

In this paper we consider continuous-time and discrete-time waveform relaxation meth-ods for general nonlinear integral-differential-algebraic equations. For the continuous-time case we derive the convergence condition of the iterative methods by invoking the spec-tral theory on the resulting iterative operators. By use of the implicit difference forms,namely the backward-differentiation formulae, we also yield the convergence condition of the discrete waveforms. Numerical experiments are provided to illustrate the theoretical work reported here.

关键词： nonlinear integral-differential-algebraic equations waveform relaxation parallel solutions convergence of iterative methods engineering applications

Kerosene-fueled supersonic combustion modeling based on skeletal mechanisms

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Acta Mechanica Sinica 2019年第6期35卷 1155-1177页

作者： Wei yao Key Laboratory of High-Temperature Gas Dynamics Institute of MechanicsChinese Academy of ScienceBeijing 100190China School of Engineering Science University of Chinese Academy of ScienceBeijing 100049China

A brief review of the recent advances in kerosene-fueled supersonic combustion modeling is present by comparing the fuels,reviewing the kinetic mechanisms,and introducing recent modeling *** advantages and disadvantages of hydrogen and kerosene for the scramjet combustor are compared to show that kerosene is a more viable fuel option for a Mach number range of ***,detailed kinetic mechanisms for kerosene,which usually contain thousands of elementary reactions,must be significantly reduced for use in *** of this writing,the smallest skeletal kerosene mechanism has only 19 species and 53 reversible *** contrast to pioneer models based on global chemistry,the current kerosene-fueled supersonic combustion models based on reduced/skeletal chemistry are classified as *** influence of kinetic mechanisms,global equivalence ratios,inlet Mach number,geometric shape,and domain symmetry are reviewed based on high-fidelity models and available *** the advances in computational technology,models with accurate descriptions of both flow and chemistry are becoming a promising,indispensable approach for the study of supersonic combustion.

关键词： Kerosene Supersonic combustion Large eddy simulation Skeletal mechanism Scramjet

Chiral ligand-protected gold nanoclusters: Considering the optical activity from a viewpoint of ligand dissymmetric field

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Progress in Natural Science:Materials International 2016年第5期26卷 428-439页

作者： Hiroshi yao Graduate School of Material Science University of Hyogo

Chirality is a geometric property of a physical, chemical, or biological object, which is not superimposable on its mirror image. Its significant presence has led to a strong demand in the development of chiral drugs, sensors,catalysts, and photofunctional materials. In recent years, chirality of nanoscale organic/inorganic hybrids has received tremendous attention owing to potential applications in chiral nanotechnology. In particular, with the recent progress in the syntheses and characterizations of atomically precise gold nanoclusters protected by achiral thiolates, atomic level origins of their chirality have been unveiled. On the other hand, chirality or optical activity in metal nanoclusters can also be introduced via the surface chiral ligands, which should be universal for the nanosystems. This tutorial review presents some optically-active metal(gold) nanoclusters protected by chiral thiolates or phosphines, and their chiroptical(or circular dichroism; CD) properties are discussed mostly from a viewpoint of the ligand dissymmetric field scheme. The examples are the gold nanoclusters protected by(R)-/(S)-2-phenylpropane-1-thiol,(R)-/(S)-mercaptosuccinic acid, phenylboronateD/L-fructose complexes, phosphine sulfonate-ephedrinium ion pairs, or glutathione. Some methodologies for versatile asymmetric transformation and chiroptical controls of the nanocluster compounds are also *** the dissymmetric field model as the origin of optical activity, the chiroptical responses of the gold nanoclusters are strongly associated with coupled oscillator and/or CD stealing mechanisms based on the concept of induced CD(ICD) derived from a perturbation theory, so on this basis, some characteristic features of the observed CD responses of chiral ligand-protected gold nanoclusters are presented in detail. We believe that various kinds of origins of chirality found in ligand-protected gold nanoclusters may provide models for understanding those of many related nanomater

关键词： Chiral ligand Monolayer-protected gold nanoclusters Dissymmetric field model Induced CD Asymmetric transformation Alloying effect

Do European Blocking Events Precede North Atlantic Oscillation Events?

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Advances in Atmospheric Sciences 2015年第8期32卷 1106-1118页

作者： yao yao LUO Dehai Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Science

Using a two-dimensional blocking index, the cause and effect relationship between European blocking （EB） events and North Atlantic Oscillation （NAO） events is investigated. It is shown that the EB event frequency is enhanced over Northern （Southern） Europe for negative （positive） phases of the NAO. Enhanced EB events over Northern Europe precede the establishment of negative phase NAO （NAO-） events, while the enhanced frequency of EB events over Southern Europe lags positive phase NAO （NAO＋） events. The physical explanation for why enhanced EB events over Northern （Southern） Europe lead （lag） NAO （NAO＋） events is also provided. It is found that the lead-lag relationship between EB events in different regions and the phase of NAO events can be explained in terms of the different latitudinal distribution of zonal wind associated with the different phases of NAO events. For NAO＋ events, the self-maintained eastward displacement of intensified midlatitude positive height anomalies owing to the intensified zonal wind can enhance the frequency of EB events over Southern Europe, thus supporting a standpoint that EB events over Southern Europe lag NAO＋ events. Over Northern Europe, EB events lead NAO- events because NAO- events arise from the self-maintained westward migration of intensified blocking anticyclones due to the weakened zonal wind in higher latitudes.

关键词： European blocking North Atlantic Oscillation mutual relationship