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Analyzing the Effect of the Intra-Pixel Position of Small PSFs for Optimizing the PL of Optical Subpixel Localization

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engineering 2023年第8期27卷 140-149页

作者： Haiyang Zhan Fei Xing Jingyu Bao Ting Sun Zhenzhen Chen Zheng You Li Yuan Department of Precision Instrument Tsinghua UniversityBeijing 100084China State Key Laboratory of Precision Measurement Technology and Instruments Tsinghua UniversityBeijing 100084China Beijing Advanced Innovation Center for Integrated Circuits Tsinghua UniversityBeijing 100084China Joint International Research Laboratory of Advanced Photonics and Electronics Beijing Information Science and Technology UniversityBeijing 100192China Beijing Institute of Control Engineering Beijing 100190Chin

Subpixel localization techniques for estimating the positions of point-like images captured by pixelated image sensors have been widely used in diverse optical measurement *** unavoidable imaging noise,there is a precision limit(PL)when estimating the target positions on image sensors,which depends on the detected photon count,noise,point spread function(PSF)radius,and PSF’s intra-pixel *** studies have clearly reported the effects of the first three parameters on the PL but have neglected the intra-pixel position ***,we develop a localization PL analysis framework for revealing the effect of the intra-pixel position of small *** accurately estimate the PL in practical applications,we provide effective PSF(e PSF)modeling approaches and apply the Cramér–Rao lower *** on the characteristics of small PSFs,we first derive simplified equations for finding the best PL and the best intra-pixel region for an arbitrary small PSF;we then verify these equations on real ***,we use the typical Gaussian PSF to perform a further analysis and find that the final optimum of the PL is achieved at the pixel boundaries when the Gaussian radius is as small as possible,indicating that the optimum is ultimately limited by light ***,we apply the maximum likelihood *** combination with e PSF modeling allows us to successfully reach the PL in experiments,making the above theoretical analysis *** work provides a new perspective on combining image sensor position control with PSF engineering to make full use of information theory,thereby paving the way for thoroughly understanding and achieving the final optimum of the PL in optical localization.

关键词： Optical measurement Subpixel localization Precision limit optimization Small point spread functions Centroiding Star sensors

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An aircraft brake control algorithm with torque compensation based on RBF neural network

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Chinese Journal of Aeronautics 2024年第1期37卷 438-450页

作者： Ning BAI Xiaochao LIU Juefei LI Zhuangzhuang WANG Pengyuan QI Yaoxing SHANG Zongxia JIAO School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Science and Technology on Aircraft Control Laboratory Beihang UniversityBeijing 100191China Key Laboratory of Advanced Aircraft Systems(Beihang University) Ministry of Industry and Information TechnologyBeijing 100091China Research Institute for Frontier Science Beihang UniversityBeijing 100191China Ningbo Institute of Technology of Beihang University Ningbo 315800China Tianmushan Laboratory Xixi Octagon CityYuhang DistrictHangzhou 310023China

The wheel brake system of an aircraft is the key to ensure its safe landing and rejected takeoff.A wheel’s slip state is determined by the brake torque and ground adhesion torque,both of which have a large degree of *** is this nature that brings upon the challenge of obtaining high deceleration rate for aircraft brake *** overcome the disturbances caused by the above uncertainties,a braking control law is designed,which consists of two parts:runway surface recognition and wheel’s slip state *** runway surface recognition,the identification rules balancing safety and braking efficiency are defined,and the actual identification process is realized through recursive least square method with forgetting *** slip state tracking,the LuGre model with parameter adaptation and a brake torque compensation method based on RBF neural network are proposed,and their convergence are *** effectiveness of our control law is verified through simulation and ground *** in the experiments on the ground inertial test bench,compared to the improved pressure-biased-modulation(PBM)anti-skid algorithm,fewer wheel slips occur,and the average deceleration rate is increased by 5.78%,which makes it a control strategy with potential for engineering applications.

关键词： Aircraft landing Brakes Disturbance observer Neural networks Runway identification

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Diminishing ether-oxygen content of electrolytes enables temperature-immune lithium metal batteries

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Science China Chemistry 2023年第9期66卷 2700-2710页

作者： Tao Liu Jingnan Feng Zhe Shi Huajun Li Weina Zhao Minglei Mao Xiangzhen Zhu Yong-Sheng Hu Hong Li Xuejie Huang Liquan Chen Liumin Suo Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Qingdao Industrial Energy Storage Research Institute Qingdao Institute of Bioenergy and Bioprocess TechnologyChinese Academy of SciencesQingdao 266101China Department of Nuclear Science and Engineering and Department of Materials Science and Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control Guangdong Key Laboratory of Environmental Catalysis and Health Risk ControlSchool of Environmental Science and EngineeringInstitute of Environmental Health and Pollution ControlGuangdong University of TechnologyGuangzhou 510006China

The reversibility of lithium(Li) metal anodes is highly susceptible to temperature,owing to the aggravated side reactions at high temperatures and serious Li dendrite growth at low *** it is extremely challenging to simultaneously realize the high Li reversibility in both low and high temperature ***,an oxygen-free solvent(n-hexane,HEX) assisted with the hexyl methyl ether and 1 mol L^(-1)lithium bis(fluorosulfonyl)imide is proposed to constitute an electrolyte for temperatureimmune lithium metal *** demonstrates that the HEX not only greatly suppresses the solvent reduction even at high temperatures but also weaken the Li~+-solvent interaction for the facile Li-ion desolvation,leading to high Li Coulombic efficiencies(99.59% at 25℃,99.30%at 60℃ and 98.75% at -30℃) and the dendrite-free Li plating from -30℃ to 60℃.Benefitting from the low density and temperature-immune properties of our electrolyte,the sulfurized polyacrylonitrile(3.8mAh cm^(-2))||Li(60 μm) pouch-cells deliver 278 Wh kg^(-1)energy density and maintain the stable performance over 50 cycles,and retain 248 and 320 Wh kg^(-1) energy density at -30℃ and 60℃,*** work provides a new perspective on the electrolyte design for wide-temperature Li metal batteries.

关键词： wide temperature range oxygen-free solvent dendrite-free Li plating high Coulombic efficiencies lithium metal batteries

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When Does Sora Show:The Beginning of TAO to Imaginative Intelligence and Scenarios engineering

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 809-815页

作者： Fei-Yue Wang Qinghai Miao Lingxi Li Qinghua Ni Xuan Li Juanjuan Li Lili Fan Yonglin Tian Qing-Long Han School of Artificial Intelligence University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory for Management and Control of Complex Systems Chinese Academy of SciencesBeijing 100190China Faculty of Innovation Engineering Macao University of Science and TechnologyMacao 999078China Department of Electrical and Computer Engineering Indiana University-Purdue University IndianapolisIndianapolisIN 46202USA Faculty of Innovation Engineering Macao University of Science and TechnologyMacao 999078China Virtual Reality Fundamental Research Laboratory Department of Mathematics and TheoriesPeng Cheng LaboratoryShenzhen 518000China State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of AutomationChinese Academy of SciencesBeijing 100190China School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyMelbourneVIC 3122Australia

DURING our discussion at workshops for writing“What Does ChatGPT Say:The DAO from Algorithmic Intelligence to Linguistic Intelligence”[1],we had expected the next milestone for Artificial Intelligence(AI)would be in the direction of Imaginative Intelligence(II),i.e.,something similar to automatic wordsto-videos generation or intelligent digital movies/theater technology that could be used for conducting new“Artificiofactual Experiments”[2]to replace conventional“Counterfactual Experiments”in scientific research and technical development for both natural and social studies[2]-[6].Now we have OpenAI’s Sora,so soon,but this is not the final,actually far away,and it is just the beginning.

关键词： something Intelligence replace

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A non-probabilistic reliability topology optimization method based on aggregation function and matrix multiplication considering buckling response constraints

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 321-336页

作者： Lei WANG Yingge LIU Juxi HU Weimin CHEN Bing HAN Institute of Solid Mechanics School of Aeronautic Science and EngineeringBeihang UniversityBeijing 100191China Aircraft and Propulsion Laboratory Ningbo Institute of TechnologyBeihang UniversityNingbo 315100Zhejiang ProvinceChina State Key Laboratory of Navigation and Safety Technology Shanghai Ship and Shipping Research InstituteShanghai 200135China National Engineering Research Center of Ship&Shipping Control System Shanghai Ship and Shipping Research InstituteShanghai 200135China

A non-probabilistic reliability topology optimization method is proposed based on the aggregation function and matrix *** expression of the geometric stiffness matrix is derived,the finite element linear buckling analysis is conducted,and the sensitivity solution of the linear buckling factor is *** a specific problem in linear buckling topology optimization,a Heaviside projection function based on the exponential smooth growth is developed to eliminate the gray *** aggregation function method is used to consider the high-order eigenvalues,so as to obtain continuous sensitivity information and refined structural *** cyclic matrix programming,a fast topology optimization method that can be used to efficiently obtain the unit assembly and sensitivity solution is *** maximize the buckling load,under the constraint of the given buckling load,two types of topological optimization columns are *** variable density method is used to achieve the topology optimization solution along with the moving asymptote optimization *** vertex method and the matching point method are used to carry out an uncertainty propagation analysis,and the non-probability reliability topology optimization method considering buckling responses is developed based on the transformation of non-probability reliability indices based on the characteristic ***,the differences in the structural topology optimization under different reliability degrees are illustrated by examples.

关键词： buckling topology optimization aggregation function uncertainty propagation analysis non-probabilistic reliability

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Modeling transport and bridging behavior of lost circulation materials in a hydraulic fracture

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岩石力学与岩土工程学报（英文版） 2025年第5期17卷 2650-2664页

作者： Shaoyi Cheng Bisheng Wu Herbert E.Huppert Tianshou Ma Zhaowei Chen Peng Tan State Key Laboratory of Hydroscience and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing100084China Key Laboratory of the Hydrosphere Sciences of the Ministry of Water Resources Beijing100084China Institute of Ocean Engineering Tsinghua UniversityBeijing100084China Institute of Theoretical Geophysics King's CollegeUniversity of CambridgeCambridgeCB2 1STUK State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina CNPC Engineering Technology R&D Company Limited Beijing102206China

Lost circulation of drilling fluid is one of the most common and costly problems in drilling *** highlights the importance of wellbore strengthening treatment sthat can utilize lost circulation materials(LCMs)to seal fractures associated with the *** this work,a numerical model ac-counting for the deformation of surrounding rock,fluid flow in the fracture,fracture propagation,and the transport of LCMs is presented to investigate the wellbore strengthening,from the fracture initiation to the fracture arrest,due to plugs formed by *** equations governing the rock deformation and fluid flow are solved by the dual boundary element method and the finite volume method,*** transport of LCMs is solved based on an empirical constitutive model in suspension flow,and several characteristic quantities are derived by dimensional *** is found that two dimensionless pa-rameters,dimensionless toughness and normalized initial particle concentration,control the migration of LCM *** numerical results show that the dimensionless toughness influences the entrance and bridging of LCMs while the initial concentration controls the location of the particle *** the initial concentration is larger than 0.8,the particle bridging tends to occur near the fracture ***,when the initial concentration is less than 0.8,the particle bridging occurs near the fracture *** work provides an effective tool to predict the LCM transport and plugging in the wellbore strengthening process.

关键词： Wellbore strengthening Lost circulation materials(LCMs) Particle bridging Hydraulic fracture Dimensional analysis Bridging location

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A Deep Reinforcement Learning control Method for a Four-Link Brachiation Robot 2

A Deep Reinforcement Learning Control Method for a Four-Link...

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2nd International Conference on Machine Learning, Cloud Computing, and Intelligent Mining, MLCCIM 2023

作者： Zhang, Xuanyu Ji, Zishang Zhang, Haodong Xiong, Rong School of Mechatronical Engineering Beijing Institute of Technology Beijing China Zhejiang University State Key Laboratory of Industrial Control and Technology Hangzhou China

ISBN: (纸本)9798350328530

Brachiation is a common way for primates to move between treetops. This movement has the characteristics of adapting to complex, discontinuous environment and low energy consumption. However, traditional control methods are often difficult to complete such tasks where the support is point-contact and discrete. Reinforcement learning (RL) gives a solution to such tasks due to its strong ability to adapt to complex environments. Therefore, in this paper, we design a four-link underactuated robot model with a pair of suspended hooks and propose a deep reinforcement learning-based control method to realize its brachiation between bars. The policy for outputting control signals is trained using the proximal policy optimization (PPO) algorithm because of its strong performance and ability to handle continuous action spaces. A reward function considering energy consumption and the challenges posed by the introduction of hooks is designed to obtain an energy-optimized control policy. Through simulation, a comparison is drawn against the author's previously proposed method of generating energy-optimal offline trajectories and tracking by model predictive control (MPC), thereby substantiating the superiority of the proposed method outlined in this paper. © 2023 IEEE.

关键词： Model predictive control

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Explosion characteristics of aluminum-based activated fuels containing fluorine

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Defence technology（防务技术） 2023年第2期20卷 34-43页

作者： Jin-tao Xu Lei Huang Hai-peng Jiang Tian-jiao Zhang Feng-qi Zhao Jian-kan Zhang Wei Gao State Key Laboratory of Fine Chemicals Department of Chemical Machinery and Safety EngineeringDalian University of TechnologyDalian116024China Beijing Institute of Aerospace Testing Technology Beijing100074China Science and Technology on Combustion and Explosion Laboratory Xi'an Modern Chemistry Research InstituteXi'an710065China

Measuring the dust explosion characteristics of aluminum-based activated fuels was a prerequisite for developing effective prevention and control *** this paper,ignition sensitivity,flame propagation behaviors and explosion severity of aluminum/polytetrafluoroethylene(Al/PTFE)compositions including 2 PT(2.80 wt.%F),4 PT(7.18 wt.%F)and 8 PT(11.90 wt.%F)were *** the content of F increased from 2.80 wt.%to 11.90 wt.%,the minimum explosive concentration MEC decreased from380 g/m^(3)to 140 g/m^(3),due to the dual effects of increased internal active aluminum and enhanced *** average flame propagation velocities increased as the percentage of F *** maximum explosion pressure Pmof 500 g/m3aluminum-based activated fuels increased from 247 k Pa to299 *** electron microscopy demonstrated that with the increase of PTFE content,the reaction was more *** this basis,the explosion mechanism of aluminum-based activated fuels was revealed.

关键词： Aluminum-based activated fuels Ignition sensitivity Flame propagation Explosion severity Explosion mechanism

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Numerical simulation of rockburst disaster and control strategy of constant resistance and large deformation anchor cable in Gaoloushan tunnel

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Journal of Mountain Science 2023年第6期20卷 1605-1619页

作者： MIAO Cheng-yu JIANG Ming LI Zhi-hu SUN Xiao-ming ZHANG Tong ZHANG Yong YANG Jin-kun REN Chao SONG Peng State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Civil Engineering Nanyang Institute of TechnologyNanyang 473000China

The Gaoloushan Tunnel in Longnan City,Gansu Province,China,frequently experiences rockburst disasters due to high in-situ *** rockburst in deep-buried tunnels remains a challenging *** paper employs RFPA(Rock Failure Process Analysis)software to establish a calculation model of constant resistance and large deformation(CRLD)anchorages and analyzes the effects of different support methods and pre-stress levels on *** simulate the process of tunnel rockburst disasters and find that ordinary anchor support incurs rockburst on the right arch waist and arch top,forming a V-shaped explosion *** anchor support has several advantages in rockburst control,such as more uniform stress distribution in the surrounding rock,a uniform distribution of plastic zones,less noticeable damage to the tunnel,and effective control of the arch top *** effectiveness of the CRLD anchor support under varying pre-stress conditions shows that a higher prestress results in a smaller plastic zone of the surrounding rock and arch top displacement and a lower number of acoustic emission signals,which better explains the excavation compensation ***,adding long anchorages in the deep surrounding rock area can better control rockburst and reduce surrounding rock *** on these findings,we propose a comprehensive control system that combines long and short anchorages and provides the optimal scheme based on ***,by using high-prestress CRLD anchor support and the combination of long and short anchorages at critical positions,we can enhance the integrity of the surrounding rock,effectively absorb the energy released by the surrounding rock deformation,and reduce the incidence of rockburst disasters.

关键词： Tunnel Rockburst RFPA Constant Resistance and Large Deformation anchor cable Long and short cable coupling support.

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Graphitic carbon nitride-based photocatalysts in the applications of environmental catalysis

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Journal of Environmental Sciences 2023年第2期124卷 570-590页

作者： Hongxia Lin JinmoWu Fan Zhou Xiaolong Zhao Pengfei Lu Guanghui Sun Yuhan Song Yayun Li Xiaoyong Liu Hongxing Dai Hefei Institute for Public Safety Research Tsinghua UniversityHefei 230601China Anhui Province Key Laboratory of Human Safety Hefei 230601China Beijing Key Laboratory for Green Catalysis and Separation Key Laboratory of Beijing on Regional Air Pollution ControlKey Laboratory of Advanced Functional MaterialsEducation Ministry of ChinaLaboratory of Catalysis Chemistry and NanoscienceDepartment of Environmental Chemical EngineeringSchool of Environmental and Chemical EngineeringFaculty of Environment and Life ScienceBeijing University of TechnologyBeijing 100124China

Semiconductor photocatalytic technology has shown great prospects in converting solar energy into chemical energy to mitigate energy crisis and solve environmental pollution *** key issue is the development of high-efficiency *** strategies in the state-of-the-art advancements,such as heterostructure construction,heteroatom doping,metal/single atom loading,and defect engineering,have been presented for the graphitic carbon nitride(g-C3N4)-based nanocomposite catalysts to design their surface chemical environments and internal electronic structures to make them more suitable for different photocatalytic *** this review,nanoarchitecture design,synthesis methods,photochemical properties,potential photocatalytic applications,and related reaction mechanisms of the modified high-efficiency carbon nitride-based photocatalysts were briefly *** superior photocatalytic performance was identified to be associated with the enhanced visible-light response,fast photoinduced electron-hole separation,efficient charge migration,and increased unsaturated active ***,the further advance of the visible-light harvesting and solar-to-energy conversions are proposed.

关键词： Graphitic carbon nitride-based photocatalyst Photocatalytic reduction Photocatalytic degradation Chemical modification Heterostructure construction Metal doping

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