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Digital twin modeling and controlling of optical power evolution enabling autonomous-driving optical networks: a Bayesian approach

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Advanced Photonics 2024年第2期6卷 69-80页

作者： Xiaomin Liu Yihao Zhang Yuli Chen Yichen Liu Meng Cai Qizhi Qiu Mengfan Fu Lilin Yi Weisheng Hu Qunbi Zhuge Shanghai Jiao Tong University State Key Laboratory of Advanced Optical Communication Systems and NetworksDepartment of Electronic Engineering

optical networks are evolving toward ultrawide bandwidth and autonomous operation. In this scenario, it is crucial to accurately model and control optical power evolutions(OPEs) through optical amplifiers(OAs), as they directly affect the signal-to-noise ratio and fiber nonlinearities. However, a fundamental contradiction arises between the complex physical phenomena in optical transmission and the required precision in network control. Traditional theoretical methods underperform due to ideal assumptions, while data-driven approaches entail exorbitant costs associated with acquiring massive amounts of data to achieve the desired level of accuracy. In this work, we propose a Bayesian inference framework(BIF) to construct the digital twin of OAs and control OPE in a data-efficient manner. Only the informative data are collected to balance the exploration and exploitation of the data space, thus enabling efficient autonomous-driving optical networks(ADONs). Simulations and experiments demonstrate that the BIF can reduce the data size for modeling erbium-doped fiber amplifiers by 80% and Raman amplifiers by 60%. Within 30 iterations, the optimal controlling performance can be achieved to realize target signal/gain profiles in links with different types of OAs. The results show that the BIF paves the way to accurately model and control OPE for future ADONs.

关键词： optical fiber communications digital twin Bayesian inference optical amplifiers autonomous-driving optical networks

Study of factors influencing the occurrence rate of 60 Hz power line radiation in the topside ionosphere:A systematic survey using the CSES satellite

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Science China(Technological Sciences) 2024年第6期67卷 1879-1892页

作者： MA ZhenHui ZHAO ShuFan LIAO Li SHEN XuHui LU HengXin School of Emergency Management Science and engineering University of Chinese Academy of SciencesBeijing100049China State Key Laboratory of space Weather National Space Science CenterChinese Academy of SciencesBeijing100190China Key Laboratory of Solar Activity and space Weather National Space Science CenterChinese Academy of SciencesBeijing100190China National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing100085China Institute of Geophysics China Earthquake AdministrationBeijing100081China

We analyze the topside ionosphere power line radiation(PLR)at 60 Hz over the US using electric field data collected by CSES satellite between January 2019 and December *** study aimed to further investigate the month-to-month variation characteristic of PLR occurrence rate observed by satellite and its several influencing factors,including solar radiation,lightning activity,and try to clarify the influence of electricity *** results show that the solar radiation(solar zenith angle and F10.7)plays a major role in the variation of the PLR occurrence rate,and that there is no direct connection with the number of *** the relationship between PLR occurrence rate and electricity consumption,the low occurrence rate associated with decreased weekend electricity consumption was not observed in the ***,there is a significant difference in PLR occurrence rate between the East and West Coasts of the US at the same latitude during the same time period,suggesting that the significant difference in PLR occurrence rate is caused by the significant difference in electricity consumption between the two *** excluding the effect of solar radiation on PLR occurrence rate,we concluded that only a significant difference in regional electricity consumption could lead to a corresponding change in PLR occurrence rate detected by the Low-Earth-Orbit ***,we also found there is seasonal variation in the diurnal differences of the PLR occurrence rate caused by seasonal variation of the lower ionosphere.

关键词： CSES satellite power line radiation occurrence rate solar radiation lightning activity electricity consumption

Stable ultraviolet ultrafast laser based on all-polarizationmaintaining fiber femtosecond laser

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Chinese Optics Letters 2024年第3期22卷 76-82页

作者：田昊朱喆林巍李子豪温俊鹏修昊范怡衡韦池一韦小明杨中民 School of Physics and Optoelectronics/State Key Laboratory of Luminescent Materials and Devices Guangdong Engineering Technology Research and Development Center of Special Optical Fiber Materials and DevicesGuangdong Provincial Key Laboratory of Fiber Laser Materials and Applied TechniquesSouth China University of TechnologyGuangzhou 510640China research Institute of Future Technology South China Normal UniversityGuangzhou 510006China

We report a high-stability ultrafast ultraviolet(UV)laser source at 352 nm by exploring an all-fiber,all-polarizationmaintaining(all-PM),Yb-doped femtosecond fiber laser at 1060 *** output power,pulse width,and optical spectrum width of the fiber laser are 6 W,244 fs,and 17.5 nm,*** UV ultrashort pulses at a repetition rate of 28.9 MHz are generated by leveraging single-pass second-harmonic generation in a 1.3-mm-long BiB_(3)O_(6)(BIBO)and sum frequency generation in a 5.1-mm-long *** maximum UV output power is 596 *** root mean square error of the output power of UV pulses is 0.54%.This laser,with promising stability,is expected to be a nice source for frontier applications in the UV wavelength window.

关键词： all-polarization-maintaining fiber ultrafast fiber laser UV laser

Physical mechanism of secondary-electron emission in Si wafers

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Chinese Physics B 2024年第4期33卷 677-681页

作者：赵亚楠孟祥兆彭淑婷苗光辉高玉强彭斌崔万照胡忠强 State Key Laboratory for Manufacturing Systems engineering Electronic Materials Research LaboratoryKey Laboratory of the Ministry of EducationEngineering Research Center of Spin Quantum Sensor ChipsUniversities of Shaanxi ProvinceSchool of Electronic Science and EngineeringXi'an Jiaotong UniversityXi'an 710049China College of Aeronautics Nanjing University of Aeronautics and AstronauticsNanjing 210016China National Key Laboratory of Science and Technology on space Microwave China Academy of Space TechnologyXi'an 710100China Department of Physics School of Physics and Electronic InformationAnhui Normal UniversityWuhu 241000China

CMOS-compatible RF/microwave devices,such as filters and amplifiers,have been widely used in wireless communication ***,secondary-electron emission phenomena often occur in RF/microwave devices based on silicon(Si)wafers,especially in the high-frequency *** this paper,we have studied the major factors that influence the secondary-electron yield(SEY)in commercial Si wafers with different doping *** show that the SEY is suppressed as the doping concentration increases,corresponding to a relatively short effective escape depthλ.Meanwhile,the reduced narrow band gap is beneficial in suppressing the SEY,in which the absence of a shallow energy band below the conduction band will easily capture electrons,as revealed by first-principles ***,the new physical mechanism combined with the effective escape depth and band gap can provide useful guidance for the design of integrated RF/microwave devices based on Si wafers.

关键词： secondary-electron yield doping concentration escape depth Si wafer

Optimal combination of the correction model and parameters for the precision geometric correction of UAV hyperspectral images

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International Journal of Agricultural and Biological engineering 2024年第3期17卷 173-184页

作者： Wenzhong Tian Za Kan Qingzhan Zhao Ping Jiang Xuewen Wang Hanqing Liu College of Mechanical and Electrical engineering Shihezi UniversityShihezi 832000XinjiangChina research center for space Information engineering Technology Shihezi 832000XinjiangChina XPCC Division of National Remote Sensing center of China Shihezi 832000XinjiangChina College of Information Science and Technology Shihezi UniversityShihezi 832000XinjiangChina

Nowadays,with the rapid development of quantitative remote sensing represented by high-resolution UAV hyperspectral remote sensing observation technology,people have put forward higher requirements for the rapid preprocessing and geometric correction accuracy of hyperspectral *** optimal geometric correction model and parameter combination of UAV hyperspectral images need to be determined to reduce unnecessary waste of time in the preprocessing and provide high-precision data support for the application of UAV hyperspectral *** this study,the geometric correction accuracy under various geometric correction models(including affine transformation model,local triangulation model,polynomial model,direct linear transformation model,and rational function model)and resampling methods(including nearest neighbor resampling method,bilinear interpolation resampling method,and cubic convolution resampling method)were ***,the distribution,number,and accuracy of control points were analyzed based on the control variable method,and precise ground control points(GCPs)were *** results showed that the average geometric positioning error of UAV hyperspectral images(at 80 m altitude AGL)without geometric correction was as high as 3.4041 m(about 65 pixels).The optimal geometric correction model and parameter combination of the UAV hyperspectral image(at 80 m altitude AGL)used a local triangulation model,adopted a bilinear interpolation resampling method,and selected 12 edgemiddle distributed *** correction accuracy could reach 0.0493 m(less than one pixel).This study provides a reference for the geometric correction of UAV hyperspectral images.

关键词： geometric correction hyperspectral images unmanned aerial vehicle(UAV) ground control point(GCP)

Experimental Study on Heat Storage Properties Comparison of Paraffin/Metal Foams Phase Change Material Composites

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Journal of Thermal Science 2024年第2期33卷 469-478页

作者： Waqar AHMED Abid HUSSAIN Hanzla SHAHID Imran ALI Hafiz Muhammad ALI Department of Mechanical engineering University of Engineering and TechnologyTaxila47080Pakistan Department of Mechanical engineering Institute of Space TechnologyIslamabadPakistan Department of Mechanical Mechatronics and Manufacturing EngineeringUniversity of Engineering and Technology LahoreFaisalabad CampusPunjabPakistan Mechanical engineering Department King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia Interdisciplinary research center for Renewable Energy and Power Systems(IRC-REPS) King Fahd University of Petroleum and MineralsDhahran31261Saudi Arabia

Heat storage properties of phase change materials(PCMs) are essential characteristics that perform a key role in thermal heat energy storage *** thermal properties of PCMs can be improved by developing metal foam/PCM *** addition of metal foam in PCMs has a significant effect on the thermal characteristics of *** this paper,the heat storage properties of two different metal foam/PCM composites were experimentally *** behavior of paraffin in metal foam(copper and iron-nickel)/paraffin composites concerning pure paraffin at a constant heat flux of 1000 W/m^(2) in three directions simultaneously(x,y,and z) was *** was infiltrated into copper and iron-nickel foams to develop composite materials which resulted in enhancing the thermal conductivity of the paraffin.A comparative analysis is made on the heat storage properties of paraffin in copper and iron-nickel foams/paraffin *** temperature distribution during the phase transition process is experimentally *** comparison indicates that temperature uniformity in copper foam/paraffin composite is better than in iron-nickel foam/paraffin composite and pure paraffin at the same heat *** results show that at heat flux of 1000 W/m^(2),the heat storage time for copper foam/paraffin composite is 20.63% of that of iron-nickel foam/paraffin composite.

关键词： heat storage capacity paraffin/metal foam composite temperature uniformity heat storage rate phase transition process

Multi-UAV Collaborative Edge Computing Algorithm for Joint Task Offloading and Channel Resource Allocation

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Journal of Communications and Information Networks 2024年第2期9卷 137-150页

作者： Yuting Wei Sheng Wu Zhe Ji Zhigang Yu Chunxiao Jiang Linling Kuang School of Information and Communication engineering Beijing University of Posts and TelecommunicationsBeijing 100876China China Academy of Electronics and Information Technology Beijing 100041China Beijing National research center for Information Science and Technology Tsinghua Space CenterTsinghua UniversityBeijing 100084China

Unmanned aerial vehicle (UAV)-based edge computing is an emerging technology that provides fast task processing for a wider area. To address the issues of limited computation resource of a single UAV and finite communication resource in multi-UAV networks, this paper joints consideration of task offloading and wireless channel allocation on a collaborative multi-UAV computing network, where a high altitude platform station (HAPS)is adopted as the relay device for communication between UAV clusters consisting of UAV cluster heads (ch-UAVs) and mission UAVs (m-UAVs). We propose an algorithm, jointing task offloading and wireless channel allocation to maximize the average service success rate (ASSR)of a period time. In particular,the simulated annealing(SA)algorithm with random perturbations is used for optimal channel allocation,aiming to reduce interference and minimize transmission delay.A multi-agent deep deterministic policy gradient (MADDPG) is proposed to get the best task offloading strategy. Simulation results demonstrate the effectiveness of the SA algorithm in channel allocation. Meanwhile,when jointly considering computation and channel resources,the proposed scheme effectively enhances the ASSR in comparison to other benchmark algorithms.

关键词： UAV-based edge computing multi-UAV collaboration joint task offloading and wireless channel allocation simulated annealing(SA)algorithm multi-agent deep deterministic policy gradient(MADDPG)

Welding depth measurement for different mode lasers using optical coherence tomography

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Chinese Optics Letters 2024年第1期22卷 41-46页

作者：谢冠明王三宏张跃强李由胡彪傅愉于起峰 Institute of Intelligent optical Measurement and Detection Shenzhen UniversityShenzhen 518060China College of Physics and Optoelectronic engineering Shenzhen UniversityShenzhen 518060China Shenzhen Sincevision Technology Co. Ltd.Shenzhen 518055China National Key Laboratory of Human Factors engineering China Astronaut Research and Training CenterBeijing 100094China College of Aerospace Science and engineering National University of Defense TechnologyChangsha 410073China

optical coherence tomography(OCT)allows a direct and precise measurement of laser welding depth by coaxially measuring the keyhole depth and can be used for process monitoring and *** OCT measurement was taken during single-beam laser welding,the keyhole instability of aluminum welding resulted in highly scattered OCT data and complicated the welding depth extraction *** a combination of an inner core beam and an outer ring beam,a novel adjustable ring mode(ARM)laser for producing a stable keyhole was applied to the OCT *** ARM laser power arrangements were conducted on aluminum and *** results indicated that the ring beam greatly improved the stability of the core beam-induced keyhole,and smooth welding depth can be extracted from the concentrated OCT data.

关键词： optical coherence tomography adjustable ring mode laser laser welding welding depth

A particle-resolved heat-particle-fluid coupling model by DEM-IMB-LBM

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Journal of Rock Mechanics and Geotechnical engineering 2024年第6期16卷 2267-2281页

作者： Ming Xia Jinlong Fu Y.T.Feng Fengqiang Gong Jin Yu Hunan Key Laboratory of Geomechanics and engineering Safety Xiangtan UniversityXiangtan411105China Zienkiewicz Institute for Modelling Data and AISwansea UniversitySwanseaSA18EPUK School of Civil engineering Southeast UniversityNanjing211189China Fujian research center for Tunneling and Urban Underground space engineering Huaqiao UniversityXiamen361021China

Multifield coupling is frequently encountered and also an active area of research in geotechnical *** this work,a particle-resolved direct numerical simulation(PR-DNS)technique is extended to simulate particle-fluid interaction problems involving heat transfer at the grain *** this extended technique,an immersed moving boundary(IMB)scheme is used to couple the discrete element method(DEM)and lattice Boltzmann method(LBM),while a recently proposed Dirichlet-type thermal boundary condition is also adapted to account for heat transfer between fluid phase and solid *** resulting DEM-IBM-LBM model is robust to simulate moving curved boundaries with constant temperature in thermal *** facilitate the understanding and implementation of this coupled model for non-isothermal problems,a complete list is given for the conversion of relevant physical variables to lattice ***,benchmark tests,including a single-particle sedimentation and a two-particle drafting-kissing-tumbling(DKT)simulation with heat transfer,are carried out to validate the accuracy of our coupled *** further investigate the role of heat transfer in particle-laden flows,two multiple-particle problems with heat transfer are *** examples demonstrate that the proposed coupling model is a promising high-resolution approach for simulating the heat-particle-fluid coupling at the grain level.

关键词： Particle-fluid interaction Heat transfer Discrete element method(DEM) Lattice Boltzmann method(LBM) Dirichlet-type thermal boundary Direct numerical simulation