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Enhanced baseline determination for formation flying LEOs by relative corrections of phase center and code residual variations

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Chinese Journal of Aeronautics 2022年第2期35卷 185-194页

作者： Bin YI Defeng GU Bing JU Kai SHAO Houzhe ZHANG College of Liberal Arts and Sciences National University of Defense TechnologyChangsha 410073China TianQin Research Center for Gravitational Physics and School of Physics and Astronomy Sun Yat-sen University(Zhuhai Campus)Zhuhai 519082China National Key Laboratory of Science and Technology on Aerospace Flight Dynamics Beijing Aerospace Control CenterBeijing 100094China

Formation flying Low Earth Orbiters(LEOs)are important for implementing new and advanced concepts in Earth observation *** Baseline Determination(PBD)is a prerequisite for LEOs to complete specified mission *** is usually performed based on space-borne GNSS data,the relative corrections of phase center and code residual variations play crucial roles in achieving the best relative orbit ***,the influences of antenna Relative Phase Centre Variations(RPCVs)and Single-Difference(SD)Melbourne-Wu¨bbena(MW)Combination Residuals Variations(SD MWVs)on PBD are *** methods were tested using flight data from Gravity Recovery And Climate Experiment(GRACE)and GRACE Follow-On(GRACE-FO).Results showed that the maximum values for RPCVs and SD MWVs were 14 mm and 0.32 cycles,***,the RPCVs correction significantly enhanced the baseline accuracy;the K-Band Ranging(KBR)measurement consistency improved by 30.1%and 37.5%for GRACE and GRACE-FO,*** application of SD MWVs further improved the accuracy and reliability of PBD *** GRACE,the ambiguities fixing success rate increased from 85.1%to 97.9%and a baseline consistency of 0.57 mm was achieved for the KBR *** was found that the correction of both RPCVs and SD MWVs reduced the carrier phase observation minus computation residuals from double-difference ionosphere-free *** addition,in-flight data processing demonstrated that RPCVs and SD MWVs estimations for the current period could be used for the previous and subsequent periods.

关键词： Ambiguity resolution Formation flying Precise baseline determination(PBD) Relative phase centre variations(RPCVs)estimation SD MW combination residuals variations(SD MWVs)estimation

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Broadband Optical Nonlinearities and Ultrafast Carrier Dynamics of GO-CuS Hybrid Film

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Journal of Lightwave technology 2025年第11期43卷 5381-5389页

作者： Zhang, Xuefeng Bai, Xuli Liu, Xiaofei Wang, Dan Han, Hong Xiao, Zhengguo Zhang, Jianguo Nie, Zhongquan Taiyuan University of Technology College of Materials Science and Engineering Institute of New Carbon Materials Taiyuan030024 China Taiyuan University of Technology Key Lab of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province College of Electronic Information and Optical Engineering Taiyuan030024 China Taiyuan Institute of Technology Department of Science Taiyuan030008 China Tongren University Department of Physics and Electronic Engineering Tongren China National University of Defense Technology College of Advanced Interdisciplinary Studies Changsha410073 China

We report the broadband optical nonlinearities and ultrafast carrier dynamics of GO doped with CuS nanoparticles (GO-CuS) following the femtosecond pulse lasers. Both the pure GO and GO-CuS hybrid films are first synthesized by the vacuum filter deposition method and their optical nonlinearities are then examined in the wide wavelength range (400 nm-1064 nm) based on the femtosecond Z-scan technique. The results reveal that, compared to the pristine GO, the introduction of CuS not only makes the GO-CuS hybrid film switched from saturated absorption to reverse saturated absorption possible, but also achieves strong broadband optical nonlinear absorption responses and optical limiting effects. It is demonstrated that the strongest nonlinear absorption coefficient (∼3.6×10-7 m/W) appears at 400 nm excitation, which is dozens of times larger than that under the illumination of 1064 nm. By leveraging the femtosecond pump-probe technique, we further study the ultrafast carrier dynamics of the GO-CuS hybrid film carrying the fast and slow relaxation processes. Moreover, the physical mechanisms behind these excellent nonlinear optical responses are elucidated. The findings presented here indicate that the GO-CuS hybrid film can be regarded as a potential promising candidate in various ultrafast photonics devices. © 1983-2012 IEEE.

关键词： Femtosecond lasers

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Decentralized control design and implementation for magnetic levitation systems with extended state observer

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control Theory and technology 2023年第3期21卷 397-413页

作者： Qiang Chen Qing Yang Mingxin Liu Peichang Yu Lianchun Wang Danfeng Zhou Jie Li Ying Tan College of Intelligence Science and Technology National University of Defense TechnologyChangsha 410073HunanChina Hunan Provincial Key Laboratory of Electromagnetic Levitation and Propulsion Technology Changsha 410073HunanChina Northwest Institute of Mechanical and Electrical Engineering Xianyang 712099Shaan'xiChina Melbourne School of Engineering The University of MelbourneMelbourne VIC 3010Australia

This paper focuses on control design and synthesize for a class of magnetic levitation systems,which have a decentralized control for each suspension *** to the existence of mechanical coupling among four suspension points,large modeling uncertainties,unpredictable disturbances during the operation,and measurement noises,becomes *** estimate and compensate for the effects of lumped uncertainties,this study employs the extended state observer(ESO)in conjunction with active disturbance rejection control(ADRC).Specifically,a novel ESO is proposed that utilizes output signals and their derivatives to estimate the lumped uncertainties more accurately,which simplifies the convergence proof conditions and has well engineering *** article is written in honor of *** on the occasion of his 60th ***,this paper is inspired by his pioneering work on composite nonlinear feedback,which combines linear feedback and nonlinear compensator to enhance system performance Chen et al.(IEEE Trans Autom control,40:427-439,2003).

关键词： Magnetic levitation systems Extended state observer Active disturbance rejection control Decentralized control

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Experimental research and energy analysis of a new type of dry ice powder pneumatic rock breaking technology

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International Journal of Mining science and technology 2023年第4期33卷 423-435页

作者： Xiaofei Wang Shaobin Hu Enyuan Wang Qiang Zhang Bing Liu Key Laboratory of Gas and Fire Control for Coal Mines(China University of Mining and Technology)Ministry of Education Xuzhou 221116China National Engineering Research Center for Coal Gas Control China University of Mining and TechnologyXuzhou 221116China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and TechnologyXuzhou 221116China School of Safety Engineering China University of Mining and TechnologyXuzhou 221116China Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering HoHai UniversityNanjing 210098China Tunnel and Underground Engineering Institute College of Civil and Transportation EngineeringHoHai UniversityNanjing 210098China China Electric Construction East China Survey and Design Institute Hangzhou 311122China

When the traditional drill and blast method is applied to rock crushing projects,it has strong vibration,loud noise and dust pollution,so it cannot be used in densely populated areas such as urban public *** developed a supercritical CO_(2)true triaxial pneumatic rock-breaking experimental system,and conducted laboratory and field tests of dry ice powder pneumatic *** characteristics of the blast-induced vibration velocity waveform and the evolution of the vibration velocity and frequency with the focal distance were analyzed and *** fracturing mechanism of dry ice powder pneumatic rock breaking is *** research results show that:(1)The vibration velocity induced by dry ice powder pneumatic rock breaking decays as a power function with the increase of the focal distance;(2)The vibration frequency caused by dry ice powder pneumatic rock breaking is mainly distributed in 1–120 *** to the dispersion effect,the dominant frequency of 10–30 Hz appears abnormally attenuated;(3)The traditional CO_(2)phase change fracturing energy calculation formula is also applicable to dry ice pneumatic rock breaking technology,and the trinitrotoluene(TNT)equivalent of fracturing energy is applicable to the Sadovsky formula;(4)Dry ice powder pneumatic rock breaking is shock wave and highenergy gas acting together to fracture rock,which can be divided into three stages,among which the gas wedge action of high-energy gas plays a dominant role in rock mass damage.

关键词： Dry ice powder pneumatic rock breaking Cracking mechanism Energy analysis Vibration frequency

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Symmetric Joint Detection and Re-Identification for UAV-Based Multiple Object Tracking 42

Symmetric Joint Detection and Re-Identification for UAV-Base...

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42nd Chinese control Conference, CCC 2023

作者： Li, Xi Zhu, Ruixiang Yu, Xianguo Cong, Yirui Liu, Guoliang Changsha University of Science and Technology Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering Changsha410004 China College of Intelligence Science and Technology National University of Defense Technology Changsha410073 China

ISBN: (纸本)9789887581543

With the development of multi-tasking learning, multi-object tracking (MOT) has been dominated by the model of Joint Detection and Re-Identification (JDR). FairMOT is a milestone work under such a paradigm. It contends that the anchor-free methods are more suitable than the anchor-based ones for building JDR models. However, the anchor-based detectors are widely used in unmanned aerial vehicle (UAV) applications since they tend to achieve higher performance for detecting small targets which are universal in drone videos. In this paper, we propose an anchor-based JDR model for the MOT task related to UAV vision. Firstly, to balance the detection task and Re-Identification (Re-ID) task, a symmetric two-branch architecture is proposed. Secondly, to deal with the correspondence problem between the two tasks, we learn Re-ID features for every anchor box. Thirdly, to alleviate the conflicts between the detection problem and the Re-ID problem, we train the model in two steps, where the detection branch is trained first, then is the Re- Id branch. Our model based on the popular anchor-based detector YOLOv7 has achieved great performance on the Visdrone- MOT20 19 dataset. The experimental results demonstrate that our model can validly complete the MOT task related to UAV visions. © 2023 Technical Committee on control Theory, Chinese Association of Automation.

关键词： Aircraft detection

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APF-Based control for On-Orbit Swarm Guard Against Multiple Threat Targets 7th

APF-Based Control for On-Orbit Swarm Guard Against Multiple ...

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7th Chinese Conference on Swarm Intelligence and Cooperative control, CCSICC 2023

作者： Wang, Hanwei Zhang, Jiacheng Zhu, Yuehe Luo, Yazhong Jin, Ke Zhang, Yu Fu, Lifeng College of Aerospace Science and Engineering National University of Defense Technology Changsha410073 China Hunan Key Laboratory of Intelligent Planning and Simulation for Aerospace Missions Changsha410073 China

ISBN: (纸本)9789819733279

With the number of satellites and space debris growing fast, it is significant to develop a swarm-to-swarm defense method to protect the on-orbit high value spacecraft. In order to solve the difficulties of swarm assignment combinations, unpredictable threat target maneuvers, non-Euclidean dynamics, and real-time control requirements, a novel method mainly based on Hungarian algorithm and artificial potential fields is proposed. The method involves rapidly searching the one-to-one mission assignment scheme and generating control laws of defenders in real time. Both a positive and a conservative defend strategy are proposed. Case studies show that the computation time of the instantaneous target assignment and control scheme is 0.08 ms. When defenders are not less than threat targets and their maneuverability are the same, the interception number is 100%. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Space debris

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Hemo-FS-SAM2: Few-Shot Tuning on Hemorrhage Segmentation of Segment Anything Model 2

Hemo-FS-SAM2: Few-Shot Tuning on Hemorrhage Segmentation of ...

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Advanced Algorithms and control Engineering (ICAACE), International Conference on

作者： Xi Wang Peng Qiao Yong Dou National Key Laboratory of Parallel and Distributed Computing College of Computer Science and Technology National University of Defense Technology National University of Defense Technology Changsha China

ISBN: (数字)9798331535087

ISBN: (纸本)9798331535094

Surgical hemorrhage is a common occurrence in surgeries. Accurate segmentation of hemorrhage regions is important for surgical navigation and post-operative assessment. Some segmentation models focused on medical images, but its performance on hemorrhage data is limited. Besides, there is an essential challenge to annotate a large number of hemorrhage data, and previous segmentation methods struggle with complex hemorrhage characteristics like unclear boundaries and scattered targets. The Segment Anything Model 2 (SAM2) shows an significant zero-shot ability in general image segmentation, and is generalizable to fine-tuned on downstream tasks. However, it often faces limitations in hemorrhage segmentation task that lacking annotations. This paper proposes a fine-tuning approach for SAM2, significantly improving its performance on hemorrhage segmentation tasks with limited data. Our method provides better segmentation performance on few-shot hemorrhage data than SAM and SAM2 based models.

关键词： Image segmentation Adaptation models Accuracy Annotations Shape Surgery Data models Hemorrhaging Tuning Biomedical imaging

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Research on Constant Power control Strategy of Marine Propulsion Converter under High Sea Conditions 8

Research on Constant Power Control Strategy of Marine Propul...

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8th Asia Conference on Power and Electrical Engineering, ACPEE 2023

作者： Cai, Zongju Ren, Qiang Zhang, Zhijie Sun, Xiran Liu, Kefan Systems Engineering Research Institute CSSC Beijing China Naval University of Engineering Key Laboratory of Marine Integrated Power Technology and National Defense Science and Technology Wuhan China

ISBN: (纸本)9798350345520

Under the conditions of strong wind, waves and high sea conditions, due to the intense movement of the ocean current, the propeller is frequently subjected to short-term high torque impact load, which causes a large fluctuation in the power generation of the electric propulsion marine power generation system, which is not conducive to the stability and economy of the diesel generator set. After the theoretical analysis of permanent magnet synchronous motor control, this paper proposes a kind of power and current double closed-loop constant power control strategy based on power feedforward, and gives a design example and test verification. The test results show that the constant power control strategy shows good dynamic performance, which can effectively reduce power ripple at the input end of the propulsion converter under high sea conditions, and make the diesel sets run efficiently. © 2023 IEEE.

关键词： Electric loads

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A novel shilling attack on black-box recommendation systems for multiple targets

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Neural Computing and Applications 2025年第5期37卷 3399-3417页

作者： Liu, Shuangyu Yu, Siyang Li, Huan Yang, Zhibang Duan, Mingxing Liao, Xiangke School of Information Science and Engineering Hunan University Hunan Changsha410082 China College of Information Technology and Management Hunan University of Finance and Economics Hunan Changsha410000 China Hunan Province Key Laboratory of Industrial Internet Technology and Security Changsha University Hunan Changsha410022 China Shenzhen Institute Hunan University Guangdong Shenzhen518063 China School of Computer Science National University of Defense Technology Hunan Changsha410073 China

In the digital era, e-platforms ubiquitously deploy recommendation systems, utilizing machine learning paradigms to tailor content according to user preferences and needs. Yet, the integrity of these systems is often compromised by shilling attacks, where malicious entities inject fake user profiles to skew product exposure and sales. This vulnerability has catalyzed research efforts to bolster the robustness and security of recommendation systems, primarily through controlled attacks and reinforcement training. This paper introduces an innovative approach to combat the inefficiency of traditional single-target shilling attacks. We propose a novel multi-target shilling strategy for black-box recommendation systems, capable of generating convincing and aggressive fake user profiles. Given the complexity of the recommendation system algorithms, we employ surrogate models to replicate and understand the target system’s behavior. The surrogate model is then subjected to attacks using our proposed methodology. An attack is deemed successful when it achieves an 80% or higher success rate against the surrogate, preluding an attack on the actual recommendation system. Our model, RWA-GAN, stands out by integrating two components: a generative adversarial network (GAN) for crafting realistic fake user profiles, and a mechanism to enhance attack success rates. This dual approach not only expedites the attack process but also ensures the generation of more authentic and well-distributed fake profiles, making the model easier to migrate. Additionally, the paper delineates several defense strategies against such attacks, contributing significantly to the discourse on enhancing the robustness of recommender systems. © The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature 2024.

关键词： Generative adversarial networks

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Opto-mechanical-thermal integration analysis of Doppler asymmetric spatial heterodyne interferometer

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中国光学（中英文） 2024年第6期17卷 1489-1511页

作者： WANG Jin-jiang JIANG Lun TONG Shou-feng PEI Hui-yi CUI Yong GUO Ming-hang School of Opto-Electronic Engineering Changchun University of Science and TechnologyChangchun 130022China Peng Cheng Laboratory Shenzhen 518000China Key Laboratory of Fundamental Science for National Defense of Aero and Ground Laser Communication Technology Changchun University of Science and TechnologyChangchun 130022China School of Mechatronics Engineering Changchun University of Science and TechnologyChangchun 130022China

In order to improve the detection accuracy of Doppler asymmetric spatial heterodyne(DASH)interferometer in harsh temperatures,an opto-mechanical-thermal integration analysis is carried ***,the correlation between the interference phase and temperature is established according to the working principle and the phase algorithm of the ***,the optical mechanical thermal analysis model and thermal deformation data acquisition model are *** deformation data of the interference module and the imaging optical system at different temperatures are given by temperature load simulation analysis,and the phase error caused by thermal deformation is obtained by ***,based on the wind speed error caused by thermal deformation of each component,a reasonable temperature control scheme is *** results show that the interference module occupies the main cause,the temperature must be controlled within(20±0.05)℃,and the temperature control should be carried out for the temperature sensitive parts,and the wind speed error caused by the part is 3.8 m/*** thermal drift between the magnification of the imaging optical system and the thermal drift of the relative position between the imaging optical system and the detector should occupy the secondary cause,which should be controlled within(20±2)℃,and the wind speed error caused by the part is 3.05 m/*** summary,the wind measurement error caused by interference module,imaging optical system,and the relative position between the imaging optical system and the detector can be controlled within 6.85 m/*** analysis and temperature control schemes presented in this paper can provide theoretical basis for DASH interferometer engineering applications.

关键词： Doppler asymmetric spatial heterodyne interferometer interference module imaging optical system opto-mechanical thermal integration analysis phase error temperature control

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