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Enhanced thermal isolation in porous thermal barrier coatings by the formation of pore guided thermal-shock cracks

science China(Technological sciences) 2023年第4期66卷 1007-1017页

作者： ZHEN Yu WU KaiJin LIU MengQi ZHENG SongLin HE LingHui YU Yin NI Yong CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsCAS Center for Excellence in Complex System MechanicsUniversity of Science and Technology of ChinaHefei 230026China National Key Laboratory of Shock Wave and Detonation Physics China Academy of Engineering PhysicsInstitute of Fluid PhysicsMianyang 621900China

Pore structure design is an effective strategy to tailor the thermal isolation capability of thermal barrier coatings(TBCs).Pursuing optimal porosity is crucial to balance the requirements of thermal isolation and mechanical reliability since the pore structure shields thermal heat transfer but increases mechanical *** this work,we investigate how thermal heat transfer couples with fracture propagation in porous TBCs by the using thermo-mechanical coupling phase field model for *** simulated results show that cracks induced by thermal shock favor deflection that is sometimes perpendicular to the direction of heat *** thermal conductivity degradation by the transverse cracks significantly impedes thermal heat transfer,leads to enhanced reduction of the effective thermal conductivity of TBCs,decreases the average thermal stress of the substrate,and thus decreases the risk of the crack penetrating into the *** numerical results demonstrate that the phase field method fully considering the thermo-mechanical interaction between cracks and pores can be a useful tool to improve the thermal isolation of porous TBCs under extreme thermal shock loadings through pore structure design.

关键词： phasefield TBCs porosity thermal shock cracks

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Facial expression recognition under occlusion conditions based on multi-feature cross-attention

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Journal of Intelligent and Fuzzy systems 2024年第4期46卷 9841-9856页

作者： Guo, Sheng Tan, Mian Cai, Shan Zhang, Zaijun Liang, Yihui Feng, Hongxi Zou, Xue Wang, Lin School of Data Science and Information Engineering Guizhou Key Laboratory of Pattern Recognition and Intelligent System Guizhou Minzu University Guiyang China School of Mathematics and Statistics Qiannan Normal University for Nationalities Key Laboratory of Complex Systems and Intelligent Optimization of Guizhou Province Duyun China Zhongshan Institute University of Electronic Science and Technology of China Zhongshan China Guizhou Aerospace Tianma Electromechanical Technology Co LTD Zunyi China

Although facial expression recognition (FER) has a wide range of applications, it may be difficult to achieve under local occlusion conditions which may result in the loss of valuable expression features. This issue has motivated the present study, as a part of which an effective multi-feature cross-attention network (MFCA-Net) is proposed. The MFCA-Net consists of a two-branch network comprising a multi-feature convolution module and a local cross-attention module. Thus, it enables decomposition of facial features into multiple sub-features by the multi-feature convolution module to reduce the impact of local occlusion on facial expression feature extraction. In the next step, the local cross-attention module distinguishes between occluded and unoccluded sub-features and focuses on the latter to facilitate FER. When the MFCA-Net performance is evaluated by applying it to three public large-scale datasets (RAF-DB, FERPlus, and AffectNet), the experimental results confirm its good robustness. Further validation is performed on a real FER dataset with local occlusion of the face. © 2024 – IOS Press.

关键词： Convolution

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A study on finite false target jamming for radar track generation

A study on finite false target jamming for radar track gener...

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2023 International Conference on Electronic Information Engineering and Data Processing, EIEDP 2023

作者： Wang, Yanqi Wang, Chao Shi, Qingzhan Huang, Jingjian Yuan, Naichang College of Electronic Science and Technology National University of Defense Technology Changsha410073 China State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System National University of Defense Technology Changsha410073 China

ISBN: (纸本)9781510666160

To solve the problem that radar can still generate effective tracks to the covered target under the existing false target jamming technology, a method of jamming radar target track generation using finite false target signals is proposed through the plot and track correlation process of the radar in the initial stage of target searching and tracking. Through electronic reconnaissance, interception, and retransmission of radar signals by a jammer, a finite number of false target signals with random movement characteristics are generated around the covered target, interfering with track correlation during target data processing by radar. Simulation examples demonstrate the effectiveness of the proposed method. © 2023 SPIE.

关键词： Data handling

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Predefined-time prescribed performance guidance law design against maneuvering target under input saturation 2

Predefined-time prescribed performance guidance law design a...

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2023 2nd International Conference on Aerospace and Control Engineering, ICoACE 2023

作者： Wei, Zhenyan Li, Jianfeng You, Weishuai Song, Shenmin Shi, Xiaoping Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory Institute of Mechanical and Electrical Engineering Beijing100072 China School of Astronautics Harbin Institute of Technology No. 92 West Dazhi Street Nangang District Harbin150001 China

A novel SMC-based prescribed performance guidance law combined with a base generator (TBG) is proposed. A TBG-based modified Lyapunov function is first proposed, which ensures that the LOS tracking error converges into zero within a predefined time. A novel sliding manifold with adjusting convergent time property is proposed, which brings about a smaller control magnitude and predefined time convergent rate. To ensure a satisfied transit and steady performance, some converted variables are defined based on which a novel prescribed performance guidance law is constructed. The input saturation problem is properly solved by designing a novel TBG-based one-order auxiliary system. Extensive simulation results have verified the effectiveness of the proposed method. © Published under licence by IOP Publishing Ltd.

关键词： Lyapunov functions

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Reliability Analysis of Model-Driven Process in Cloud Manufacturing systems 18th

Reliability Analysis of Model-Driven Process in Cloud Manu...

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18th Chinese Intelligent systems Conference, CISC 2022

作者： Yang, Hao Zhao, Chun Shen, Nana Computer School Institution of Smart Manufacturing and Complex System Beijing Information Science and Technology University Beijing100101 China

ISBN: (纸本)9789811962257

Model-based system engineering solves the multi-disciplinary, cross-domain issues faced by complex system development groups. Model-driven methods, which use models to drive the whole process of the system, also become an important technology. The reliability analysis of complex system model is helpful to improve the research and development level of complex system, improve and ensure the confidence of model-driven system, and reduce the uncertainty in the driving process, which is also the basis of the model-driven method. This paper introduces the research progress of the reliability analysis technology of complex system based on the model. It puts forward the reliability verification method of the model in the driving process, which can establish the fault tree of the system according to the model, and then carry out the fault analysis through Monte Carlo simulation to realize the complex large-scale dynamic fault tree analysis (FTA). It provides a new reference for the model reliability verification of complex systems in the process of model-driven. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Reliability analysis

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A Multimodal Image Matching Algorithm Based on Structure Feature 1

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International Conference on Guidance, Navigation and Control, ICGNC 2022

作者： Wang, Xing Zhao, Jiajia su, Ang Guan, Banglei Dong, Jing Han, Songlai Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory Beijing100074 China College of Aerospace Science and Engineering National University of Defense Technology Changsha410073 China Research Institution of Aerospace Technology Central South University Changsha410083 China

ISBN: (数字)9789811966132

ISBN: (纸本)9789811966125

Multimodal image matching is a crucial technique for aircraft navigation in GPS denied environment. However, the nonlinear radiometric difference between multimodal images and significant image noise make this task considerably challenging. A multimodal image registration algorithm build on structural features is presented. The method can also accurately extract structural features in the case of severe noise distortion. Besides, A similarity measure method based on parallelism is presented for adapting nonlinear grayscale distortion. The evaluation show that the algorithm has significant superiority over other state-of-the-art algorithms. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Principal component analysis

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Anti-Jamming Null Space Projection Beamforming Based on Symbiotic Radio

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Computer Modeling in Engineering & sciences 2024年第1期138卷 679-689页

作者： Baofeng Ji Yifan Liu Tingpeng Li Ling Xing Weixing Wang Shahid Mumtaz Xiaolong Shang Wanying Liu Congzheng Han State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System(CEMEE) Luoyang471000China Research and Innovation Center of Intelligent System Longmen LaboratoryLuoyang471000China College of Information Engineering Henan University of Science and TechnologyLuoyang471000China Institute of Atmospheric Physics Chinese Academy of Sciences(LAGEO)Beijing100000China Instituto de Telecomunicaes Aveiro3800-005Portugal Chinese Academy of Agricultural Mechanization Sciences Beijing100000China

With the development of information technology,more and more devices are connected to the Internet through wireless communication to complete data *** to the broadcast characteristics ofwireless channels,wireless networks have suffered more and more malicious *** layer security has received extensive attention from industry and *** is considered to be one of the most important technologies related to physical layer *** beamforming technology,messages can be transmitted to legitimate users in an offset direction that is as orthogonal as possible to the interference channel to ensure the reception SINR by legitimate *** the symbiotic radio(SR)technology,this paper considers a symbiotic radio antijamming MIMO system equipped with a multi-antenna system at the main base *** order to avoid the interference signal and improve the SINR of the signal received by the *** base station is equipped with a uniform rectangular antenna array,and using Null Space Projection(NSP)Beamforming,Intelligent Reflecting Surface(IRS)can assist in changing the beam’s *** simulation results show that NSP Beamforming could make a better use of the null space of interference,which can effectively improve the received SINR of users under directional interference,and improve the utilization efficiency of signal energy.

关键词： Symbiotic radio anti-jamming MIMO NSP Beamforming physical layer security

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A Light Gradient Boosting Machine Based Effectiveness Prediction Method of Space Reconnaissance system

A Light Gradient Boosting Machine Based Effectiveness Predic...

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IEEE Advanced Information technology, Electronic and Automation Control Conference (IAEAC)

作者： Jiahuan Liu Ping Jian Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing China

To address the problem of effectiveness evaluation of space reconnaissance systems with limited data sets, vast array of indexes and inadequate model interpretability, an interpretable effectiveness prediction method based on Light Gradient Boosting Machine(LightGBM) and the Shapley Additive exPlanations(SHAP) is proposed. The thorough evaluation process is given and the index system of space reconnaissance systems is built. Then LightGBM is used to establish a nonlinear mapping the model between the indexes and the effectiveness. Additionally, the model’s hyperparameters are adjusted using Bayesian optimization to improve accuracy and lessen computational load. Furthermore, the feasibility of the proposed method is validated by modeling and evaluating the performance of the space reconnaissance system under a particular operational scenario. The experimental results show that compared with other mainstream machine learning methods, the proposed method has higher prediction accuracy and can efficiently extract the potential characteristics of the space reconnaissance system.

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Combining Local Electromagnetic Scattering and Global Structure Features for SAR Open Set Recognition

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IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 2025年 18卷 12572-12587页

作者： Lin, Qinjie Sun, Hao Xu, Yanjie Wang, Junyu Ji, Kefeng Kuang, Gangyao National University of Defense Technology State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and Technology Changsha410073 China

Automatic target recognition (ATR) is crucial for synthetic aperture radar (SAR) image interpretation. However, existing SAR ATR primarily rely on algorithms from the field of computer vision, many methods have not adequately considered the imaging sensitivity of SAR images. Moreover, SAR ATR typically follows the closed set assumption, but in dynamic and open real-world environments, SAR systems may encounter target classes that have not been seen during training. To address these issues, this article proposes an SAR open set recognition (OSR) method that combines local electromagnetic scattering and global structure features. The global structural features focus on the overall relationship between target and background, while the local electromagnetic scattering features can effectively capture the scattering characteristics of target. Hence, we construct a global and local feature guidance network, fuses these complementary features as prior knowledge to guide deep features. Then, a class-anchor-based loss function is constructed by anchor loss and tuple loss, which cluster the features of known classes targets around predefined class anchors. Finally, the distance ratio is calculated to identify known classes targets and reject unknown classes targets. The experimental results on the MSTAR and SAR-ACD datasets show that our method outperforms other OSR methods in recall, precision, F1, and accuracy, demonstrating a superior performance in OSR. © 2008-2012 IEEE.

关键词： Automatic target recognition

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Multi-domain blind source separation in-band full-duplex technique considering RF impairments 4

Multi-domain blind source separation in-band full-duplex tec...

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2023 4th International Conference on Electrical, Electronic Information and Communication Engineering, EEICE 2023

作者： Zhu, Hong Yu Wang, Chao Yuan, Nai Chang Huang, Jing Jian Wang, Qing Ping College of Electronic Science and Technology National University of Defense Technology Changsha410073 China State Key Lab. of Complex Electromagnetic Environment Effects on Electronics and Information System National University of Defense Technology Changsha410073 China

In-band full-duplex (IBFD) technology can potentially improve spectrum efficiency compared to half-duplex technology. The cancellation of the self-interference (SI) signal is the key to implementing the IBFD system to achieve accurate detection of the signal of interest. In this work, we fully account for the effect of IQ imbalance, phase noise (PN), additional Gaussian white noise (AWGN), and the nonlinear caused by the RF impairments of power amplifier, and adopt the method of canceling SI signal combined with the propagation, analog, and digital domain to cancel the SI signal, but the residual SI signal is still mixed with the signal of interest in the same time and frequency domain. In addition, a novel multi-domain blind source separation (MDBSS) self-interference cancellation method implemented by using the off-the-shelf components is proposed in this paper, which can realize the separation of residual self-interference signals from the signal of interest (SOI). Additionally, the multi-domain blind source separation (MDBSS) self-interference cancellation technique is used to achieve 75 dB of self-interference cancellation performance, which is proven through numerical simulation analysis, and the SOI is successfully separated in the receiver. Moreover, the multi-domain blind source separation (MDBSS) method in this paper can be applied to radar, jammer, and communication systems in the future. © Published under licence by IOP Publishing Ltd.

关键词： Blind source separation

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