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11th International Conference on Image and Graphics, ICIG 2021

作者： Hu, Xinyu Gao, Jingpeng Jiang, Zhiye College of Information and Communication Engineering Harbin Engineering University Harbin 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)9783030873578

To solve the problem that the deviation of the Unmanned Aerial Vehicle (UAV) flight status data collected by the equipment during flight leads to the failure of the mission, this paper proposes a UAV track planning algorithm based on Graph Attention Network and Deep Q Network (DQN). Firstly, we use the camera to collect images and apply pre-trained ResNet to extract image features. Secondly, we adopt the Graph Attention Network to establish the connection between the sensor-measured flight state information and the actual flight state information. Thirdly, we build the optimization model of flight state. Moreover, based on the Deep Reinforcement Learning (DRL) theory, the DQN-based UAV track planning system is trained. Finally, the system combined the optimized flight state to complete the optimal flight action output to realize the track planning. Simulation results show that, compared with the original algorithm which is under the same flight conditions as the proposed algorithm, the velocity deviation rate of the proposed algorithm is improved by 46.79%, which can plan a high-quality track and has good engineering application value. © 2021, Springer Nature Switzerland AG.

关键词： Image processing

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DFT study of elastic, structural, and optical properties of K2InAgZ6 (Z = Cl, Br, I) perovskites: potential for optoelectronic applications

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Optical and Quantum Electronics 2024年第12期56卷 1-17页

作者： Ahmad, Sohail Zakria, Muhammad Alotaibi, Khalid M. Huma, Tabasum Hakimi, Nadimullah Ali, Rawaid Qasimullah Safeen, Akif Feng, Jing Shah, Syed Hatim Faculty of Materials Science and Engineering Kunming University of Science and Technology Kunming650093 China Pakistan Institute of Engineering and Applied Sciences National Institute of Lasers and Optronics College Nilore Islamabad45650 Pakistan Department of Chemistry Collage of Science King Saud University PO Box 2455 Riyadh11541 Saudi Arabia Faculty of Metallurgical and Energy Engineering Kunming University of Science and Technology Kunming650093 China College of Physical and Electronic Information Technology Key Laboratory of Advanced Techniques for Renewable Energy Materials Ministry of Education Yunnan Normal University Kunming650500 China Faculty of Physical and Numerical Sciences Qurtuba University of Science and Information Technology Peshawar Peshawar25100 Pakistan Department of Physics University of Poonch Rawalakot AJK Poonch12350 Pakistan

In this article, a comprehensive research was carried out to investigate the elastic, structural, and optoelectronic properties of double perovskite compounds K2InAgCl6, K2InAgBr6, and K2InAgI6 by using density functional theory. Goldsmith’s tolerance factor (tG), whose values are near to unity, was used to assess the structural stability of the cubic perovskite structure. According to the analysis of electronic characteristic, K2InAgCl6, K2InAgBr6, and K2InAgI6 are semiconductors with a tiny band gap, calculated using the mBJ-PBE sol potential with band gap values of 2.48 eV, 1.47 eV, and 0.23 eV, respectively. A comprehensive analysis of the optical characteristics of these compounds was conducted across an energy range from 0 to 10 eV. The results revealed that K2InAgCl6, K2InAgBr6, and K2InAgI6 exhibit significant conductivity and absorbance properties in wide energy ranges, which is confirmed by density of states analysis. Moreover, the optical characteristics shows that lower photon energy relates to high optical transmission, while higher energies result in more optical absorption of material. These results demonstrate that K2InAgCl6, K2InAgBr6, and K2InAgI6 are viable material candidates for use in high-frequency UV optical devices. © The Author(s), under exclusive licence to Springer science+Business Media, LLC, part of Springer Nature 2024.

关键词： Perovskite

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A Radar Signal Modulation Recognition Algorithm Based on Multi-branch Fusion Difference

A Radar Signal Modulation Recognition Algorithm Based on Mul...

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IEEE International Conference on Electronic Information and Communication technology (ICEICT)

作者： Sisi Jiang Jingpeng Gao Zhiye Jiang Fang Ye College of Information and Communication Engineering Harbin Engineering University Haibin China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China National Key Laboratory of Underwater Acoustic Technology College of Information and Communication Engineering Harbin Engineering University Harbin China

The time-frequency images of radar modulation signals are similar at low signal-to-noise ratios, which will lead to lower recognition accuracy. This paper proposes an algorithm based on multi-branch fusion differences to identify radar modulation signals. The algorithm designs a multi-branch fusion differential module based on the attention mechanism and differential thinking, to extract time-frequency image fine-grained features and improve the Convolution Neural Network characterization ability. After that, a dual-branch differential network is proposed by combining vanilla convolution and multi-branch fusion difference module. The network can fuse global and detailed features of time-frequency images, which can achieve radar signal modulation recognition. The simulation results show that the recognition accuracy of the algorithm can reach 93.17% at 0dB. Therefore, the algorithm can obtain high recognition accuracy and has high recognition performance.

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Effects of Dropsonde Data in Field Campaigns on Forecasts of Tropical Cyclones over the Western North Pacific in 2020 and the Role of CNOP Sensitivity

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Advances in Atmospheric sciences 2023年第5期40卷 791-803页

作者： Xiaohao QIN Wansuo DUAN Pak-Wai CHAN Boyu CHEN Kang-Ning HUANG State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210044China Hong Kong Observatory Hong KongChina Weather Forecasting Office National Meteorological CenterChina Meteorological AdministrationBeijing 100081China Research and Development Center Central Weather BureauTaipei 100006China

Valuable dropsonde data were obtained from multiple field campaigns targeting tropical cyclones,namely Higos,Nangka,Saudel,and Atsani,over the western North Pacific by the Hong Kong Observatory and Taiwan Central Weather Bureau in *** conditional nonlinear optimal perturbation(CNOP)method has been utilized in real-time to identify the sensitive regions for targeting observations adhering to the procedure of real-time field campaigns for the first *** observing system experiments were conducted to evaluate the effect of dropsonde data and CNOP sensitivity on TC forecasts in terms of track and intensity,using the Weather Research and Forecasting *** is shown that the impact of assimilating all dropsonde data on both track and intensity forecasts is ***,assimilation using only the dropsonde data inside the sensitive regions displays unanimously positive effects on both the track and intensity forecast,either of which obtains comparable benefits to or greatly reduces deterioration of the skill when assimilating all dropsonde ***,these results encourage us to further carry out targeting observations for the forecast of tropical cyclones according to CNOP sensitivity.

关键词： tropical cyclones targeting observation field campaign CNOP sensitivity dropsonde intensity forecasts

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On the metric resolvent: nonexpansiveness, convergence rates and applications

arXiv

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arXiv 2021年

作者： Xue, Feng National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

In this paper, we study the nonexpansive properties of metric resolvent, and present a convergence rate analysis for the associated fixed-point iterations (Banach-Picard and Krasnosel’skii-Mann types). Equipped with a variable metric, we develop the global ergodic and non-ergodic iteration-complexity bounds in terms of both solution distance and objective value. A byproduct of our expositions also extends the proximity operator and Moreau’s decomposition identity to arbitrary variable metric. It is further shown that many classes of the first-order operator splitting algorithms, including alternating direction methods of multipliers, primal-dual hybrid gradient and Bregman iterations, can be expressed by the fixed-point iterations of a simple metric resolvent, and thus, the convergence can be analyzed within this unified *** Codes 68Q25, 47H05, 90C25, 47H09 Copyright © 2021, The Authors. All rights reserved.

关键词： Iterative methods

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Seamless Prediction in China: A Review

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Advances in Atmospheric sciences 2023年第8期40卷 1501-1520页

作者： Hong-Li REN Qing BAO Chenguang ZHOU Jie WU Li GAO Lin WANG Jieru MA Yao TANG Yangke LIU Yujun WANG Zuosen ZHAO State Key Laboratory of Severe Weather and Institute of Tibetan Plateau MeteorologyChinese Academy of Meteorological SciencesBeijing 100081China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Department of Atmospheric Science School of Environmental StudiesChina University of GeosciencesWuhan 430074China China Meteorological Administration Key Laboratory for Climate Prediction Studies National Climate CenterChina Meteorological AdministrationBeijing 100081China Ensemble Forecasting Division CMA Earth System Modeling and Prediction Center(CEMC)Beijing 100081China School of Atmospheric Sciences Chengdu University of Information TechnologyChengdu 610225China

Seamless prediction is a weather-climate integrated prediction covering multiple time scales that include days,weeks,months,seasons,years,and *** prediction can provide different industries with information such as weather conditions and climate variations from the next few days to years,which have important impacts on economic and social development and important reference value for short-,medium-and long-term decision-making and planning of the ***,seamless prediction has received widespread attention from the international scientific community *** Chinese scientists have also carried out relevant research,this paper reviews the research in China on developments and applications of seamless prediction methods and prediction systems in recent *** them,the main progress of seamless prediction methods studies is reviewed from four aspects:short-and medium-range weather forecasting,subseasonal-to-seasonal,seasonal-to-interannual,and decadal climate *** terms of development and application of seamless prediction systems,the main achievements made by meteorological operational departments,scientific institutes,and universities in China in recent years are ***,some of the issues in seamless prediction that need further study are discussed.

关键词： seamless prediction weather-climate integrated prediction prediction system

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Periodic Structures and Its Interaction to EM Wave Spectrum, Ideas From X-Ray to MW Wave

Periodic Structures and Its Interaction to EM Wave Spectrum,...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yunhui Tang Lu Gao Ruzhi Wang Shengjun Zhang Hang Song Yuning Zhang Xia Ai Lei Xie Luting Jiao Xiaoling Zhang Jing He Jiaqi Liu Beijing University of Technology Beijing China National Key Laboratory of Science & Technology on Test Physics and Numerical Mathematics Beijing China Beijing Institute of Space Long March Vehicle Beijing China

X-ray is an important tool for characterizing materials, which is based on the idea that all crystals are composed of atoms or molecules stacking in a particular type, basically expressing as unit cell, diffracting the incident ray with a proper type. In analogue, the periodic structures which are mostly constructed artificially show special desired properties, such as the properties of grating, frequency selective surfaces, metamaterials and metasurface. In this paper, A study was done on the insight of the relation of wave interaction with periodic structures based on X-ray diffraction and control of electromagnetic waves.

关键词： Frequency selective surfaces Stacking Electromagnetic scattering Crystals X-ray diffraction Metasurfaces Computational electromagnetics

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Influence of the NAO on Wintertime Surface Air Temperature over East Asia:Multidecadal Variability and Decadal Prediction

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Advances in Atmospheric sciences 2022年第4期39卷 625-642页

作者： Jianping LI Tiejun XIE Xinxin TANG Hao WANG Cheng SUN Juan FENG Fei ZHENG Ruiqiang DING Frontiers Science Center for Deep Ocean Multispheres and Earth System-Key Laboratory of Physical Oceanography-Institute for Advanced Ocean Studies-Academy of the Future Ocean Ocean University of ChinaQingdao 266100China Laboratory for Ocean Dynamics and Climate Pilot Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China College of Global Change and Earth System Sciences Beijing Normal UniversityBeijing 100875China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China

In this paper,we investigate the influence of the winter NAO on the multidecadal variability of winter East Asian surface air temperature(EASAT)and EASAT decadal *** observational analysis shows that the winter EASAT and East Asian minimum SAT(EAmSAT)display strong in-phase fluctuations and a significant 60-80-year multidecadal variability,apart from a long-term warming *** winter EASAT experienced a decreasing trend in the last two decades,which is consistent with the occurrence of extremely cold events in East Asia winters in recent *** winter NAO leads the detrended winter EASAT by 12-18 years with the greatest significant positive correlation at the lead time of 15 *** analysis shows that ENSO may affect winter EASAT interannual variability,but does not affect the robust lead relationship between the winter NAO and *** present the coupled oceanic-atmospheric bridge(COAB)mechanism of the NAO influences on winter EASAT multidecadal variability through its accumulated delayed effect of~15 years on the Atlantic Multidecadal Oscillation(AMO)and Africa-Asia multidecadal teleconnection(AAMT)*** NAO-based linear model for predicting winter decadal EASAT is constructed on the principle of the COAB mechanism,with good hindcast *** winter EASAT for 2020-34 is predicted to keep on fluctuating downward until~2025,implying a high probability of occurrence of extremely cold events in coming winters in East Asia,followed by a sudden turn towards sharp *** predicted 2020/21 winter EASAT is almost the same as the 2019/20 winter.

关键词： winter East Asian surface air temperature North Atlantic Oscillation Atlantic Multidecadal Oscillation Africa-Asia multidecadal teleconnection pattern coupled oceanic-atmospheric bridge multidecadal variability

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Rapid increase in warm-wet compound extreme events with high health risks in southern China:Joint influence of ENSO and the Indian Ocean

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Advances in Climate Change Research 2023年第6期14卷 856-865页

作者： Cai-Meng LIANG Liang ZHAO Shun-Wu ZHOU Xin-Yong SHEN Cun-Rui HUANG Yi-Hui DING Yan-Ju LIU Hao-Xin YAO Kai-Xing ZHOU Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Numerical Modeling for Atmosphere Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric PhysicsChinese Academyof SciencesBeijing100029China Key Laboratory of South China Sea Meteorological Disaster Prevention and Mitigation of Hainan Province Haikou 570203China Vanke School of Public Health Tsinghua UniversityBejing 100084China Institute of Healthy China Tsinghua UniversityBeijing 100084China National Climate Center China Meteorological AdministrationBejing 100081China Beijing Institute of Electronic System Engineering Bejing 100854China

High temperature and high humidity pose notable threats to the health and survival of humans,and the impact of compound extreme events involving multiple meteorological elements is usually greater than the sum of the impacts of individual extreme ***,there is limited research on the compound extreme meteorological events,defined based on the extreme of health risks rather than just the extreme of meteoro-logical elements,necessitating further investigation into their characteristics and underlying driving *** daily records of emergency ambulance dispatches from selected Chinese cities,together with daily average temperature and relative humidity data,this study identified and quantified warm-wet compound extreme events with high health risks(HRWWs)that occurred in southern China during *** revealed that HRWWs were most prevalent in the coastal region of southern *** annual frequency of HRWWs across China underwent a marked shift in 2014,with the rapid increase in recent years primarily contributed by the increase in summer HRWWs and advance and extension of the period of occurrence of HRWWs in *** analysis indicated that the changes in HRWWs in southern China during summer were primarily regulated by the EIl Nino-Southern Oscillation(ENSO)of the preceding winter and the springtime Indian Ocean basin-wide(IOBW)*** Nino and Indian Ocean warming force a reverse Walker circulation in the tropical Indian Ocean-western Pacific,strengthening the Philippine anticyclone(PAC)in *** weakens convection in the northwestern Pacific and enables the western Pacific subtropical high to extend westward over coastal areas of southern *** resulting abnormal atmospheric circulation causes prevailing subsidence over southern China,which is unfavorable for precipitation but conducive to maintaining high surface *** reduced precipitation,water vapor flux is increased owing to strengthened southwesterlies

关键词： Health risk Warm-wet compound events ENSO IOBW

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Characteristic Mode Design of Dual-Band Multistate Tunable Absorber Based on Programmable Flexible Metasurface

TechRxiv

引用

TechRxiv 2022年

作者： Li, Mengmeng Ning, Zihao Ding, Dazhi Ai, Xia Liu, Jiaqi Wang, Chao-Fu The Department of Communication Engineering Nanjing University of Science and Technology Nanjing China The National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China The Department of Electrical and Computer Engineering National University of Singapore Singapore

Theory of characteristic modes (TCM) is applied to the design of a programmable flexible metasurface (PFMS) to achieve its multistate tunable microwave absorption. The designed metasurface consists of two layers. The first layer is a very thin polyimide (PI), on which unit cells consisting of two trapezoidal patches symmetrical along the central bias microstrip are printed. The second layer is grounded polyvinyl chloride (PVC) substrate to maintain the flexibility of the designed structure. The TCM is used to analyze and understand the modal behavior of the unit cell, which provides clear underlying electromagnetic (EM) physics to guide us how to load positive-intrinsic-negative (PIN) diode as a tunable resistance to achieve variable absorption states. The designed PFMS absorber have been fabricated and experimentally verified on the flat and cylindrical foams, respectively. Good agreements can be found for both planar and cylindrical metasurface structures between full-wave simulations and measurements. Less than -10 dB reflectivity is achieved from 3.6 to 10.7 GHz (99%). The mimicry of time-varying scattering cross section (SCS) is further realized through real-time coding PFMS absorber, which can be precisely tuned from -30 dB to 0 dB with a step of 1.5 dB at 5.5 GHz and 10.4 GHz, respectively. © 2022, CC BY.

关键词： Polyvinyl chlorides

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