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Functional Connectivity Network Augmentation with Patch-entirety Self-attention GAN for ADHD Identification

IEEE Transactions on Instrumentation and Measurement 2025年 74卷

作者： Pei, Shengbing Jiang, Wencong Cao, Shuai Fan, Cunhang Liang, Wen Lv, Zhao Guan, Jihong Zhang, Chao Anhui University Anhui Province Key Laboratory of Multimodal Cognitive Computation School of Computer Science and Technology Hefei230601 China Anhui University Institutes of Physical Science and Information Technology Hefei230601 China Google Company Mountain View94043 United States Civil Aviation Flight University of China Guanghan618307 China Tongji University Department of Computer Science and Technology Shanghai201800 China

Functional connectivity network (FCN) describes the cooperative state of the brain and is often used to identify neurological diseases. However, the performance of FCN-based recognition models is limited by small sample size for the high cost of patient data acquisition and labeling. Generative adversarial networks (GAN) can generate diverse samples to alleviate this problem. Due to the symmetry of FCN matrix, existing GAN-based data augmentation methods mainly adopt fully connected layers to learn flattened FCN data distribution, neglecting the functional collaboration structure within FCN. Here, we propose a novel patch-entirety self-attention GAN (PEGAN) for FCN data augmentation, thereby helping to improve brain disorder identification. PEGAN is a fully convolutional structure, and contains a two-stage attention mechanism to learn the collaboration of brain regions, at the first stage, the FCN is partitioned into multiple patches, each patch is encoded by itself with self-attention, this is to learn local consistency characteristic within a specific brain sub-function;at the second stage, the global self-attention involving all functional connections is performed, this is to learn the global collaborative characteristic of the entire brain. Meanwhile, a symmetry constraint is designed in the optimization objective of GAN to overcome the issue that the convolutional GAN model is not applicable to FCN data. With the sufficient augmentation data, a dual-stream network is trained for classification. Experimental results on ADHD-200 dataset indicates that 1) the proposed identification method with PEGAN demonstrates its superiority by comparing with existing ADHD identification methods;2) the improved optimization objective function effectively solves the problem that FCN data is not suitable for convolution processing;3) the reliability of the generated FCN data with PEGAN is verified from both qualitative and quantitative perspectives;4) the augmented FCN data can

关键词： Neurodegenerative diseases

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Improving Physical-Layer Security in ISAC-UAV System: Beamforming and Trajectory Optimization

arXiv

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arXiv 2024年

作者： Xiu, Yue Lyu, Wanting Yeoh, Phee Lep Ai, Yi Li, Yonghui Wei, Ning College of Air Traffic Management Civil Aviation Flight University of China Deyang618311 China National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of China Chengdu611731 China School of Science Technology and Engineering University of the Sunshine Coast QLD Australia School of Science Technology and Engineering Southwest Jiaotong University Chengdu China School of Electrical and Information Engineering University of Sydney SydneyNSW2006 Australia

This paper investigates a novel unmanned aerial vehicle (UAV) secure communication system with integrated sensing and communications. We consider wireless security enhancement for a multiple-antenna UAV transmitting ISAC waveforms to communicate with multiple ground Internet-of-Thing devices and detect the surrounding environment. Specifically, we aim to maximize the average communication secrecy rate by optimizing the UAV trajectory and beamforming vectors. Given that the UAV trajectory optimization problem is non-convex due to multivariable coupling develop an efficient algorithm based on the successive convex approximation (SCA) algorithm. Numerical results show that our proposed algorithm can ensure the accuracy of sensing targets and improve the communication secrecy rate. Copyright © 2024, The Authors. All rights reserved.

关键词： Unmanned aerial vehicles (UAV)

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An Incident Angle Insensitive Absorption Frequency Selective Surface

An Incident Angle Insensitive Absorption Frequency Selective...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Zhendong Bai Min Xu Peng Liu Lu Gao Jiaqi Liu National Key Laboratory of Science and Technology on Test Ph Beijing Institute of Space Long March Vehicle Beijing China Department of Aeronautical Engineering Army Aviation Institue Beijing China

In this paper, a novel angle insensitive frequency selective surface (FSS) is presented by combining the ring, square loop and cross to achieve better electromagnetic absorption performance. The unit cell consists of three layers, which are FSS, dielectric layer and patch substrate. The structure makes the reflections and transmission of the two sides not equal. The simulation results show that the proposed FSS provides absorption on several distinctive frequency bands ranging from C-band to K-band with maximum absorption of 99%.

关键词： Frequency selective surfaces Radar cross-sections Absorption Surface waves K-band Simulation Radar antennas

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CMAS + sea salt corrosion to thermal barrier coatings

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Corrosion science 2023年第1期218卷

作者： Guo, Lei Zhang, Xinmu Liu, Mingguang Yang, Shuo Dai, JianWei School of Materials Science and Engineering Tianjin University Tianjin300072 China Tianjin Key Laboratory of Advanced Joining Technology Key Lab of Advanced Ceramics and Machining Technology of Ministry of Education Tianjin300072 China Naval Logistics Academy Tianjin300450 China Center for analysis and Test Tianjin University 300072 China Key laboratory for advanced corrosion and protection of aviation materials AECC Beijing Institute of Aeronautical Materials Beijing100095 China

In marine environment, sea salt and calcium-magnesium-alumina-silicate (CMAS) coexist largely endangering thermal barrier coatings (TBCs) service safety. In this study, the corrosion behavior of synthetic sea salt and CMAS to TBCs was investigated. Sea salt changed the CMAS structure, thereby decreasing its melting temperature and high-temperature viscosity. At 1200 ℃, CMAS + sea salt completely melted but CMAS did not;at 1250 ℃, both melted while CMAS + sea salt had stronger penetration ability in TBCs than CMAS. Thus, TBCs which have not been or are less affected by CMAS may be damaged due to CMAS + sea salt attack. © 2023 Elsevier Ltd

关键词： Alumina

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Corrosion Behaviour of 2198 Aluminium-Lithium Alloy in Alternating Wet and Dry Environments

SSRN

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SSRN 2024年

作者： Liu, Yingyan Deng, Zhibin Zhang, Qian Hu, Xiao Yue, Hang Tang, Haiping Li, Guotao Civil Aviation Flight University of China Guanghan618307 China Civil Aircraft Fire Science and Safety Engineering Key Laboratory of Sichuan Province Guanghan618307 China Sichuan Key Technology Engineering Research Center for All-electric Navigable Aircraft Guanghan618307 China Petrochina Company Limited Yunnan671000 China

The corrosion behavior and mechanisms of 2198 aluminum-lithium alloy under alternating wet-dry conditions in a simulated marine atmospheric environment were investigated using weight loss measurement, electrochemical impedance spectroscopy (EIS), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), macroscopic morphology analysis, 3D profilometry, and X-ray photoelectron spectroscopy (XPS). The results indicate that corrosion weight loss increases with decreasing wet-to-dry ratios, accompanied by an increase in the corrosion rate. Various data suggest that the primary corrosion products are composed of Al2O3, AlO(OH), and AlCl3. The reduction in the wet-to-dry ratio leads to the enrichment of Cl⁻ within the corrosion products, extending the contact time between the substrate and the medium, thereby intensifying the hydrolysis of Al³⁺. This exacerbates the dissolution at pitting sites, which in turn erodes and breaks down the corrosion product film, accelerating the overall corrosion process. © 2024, The Authors. All rights reserved.

关键词： Electrochemical impedance spectroscopy

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Effect of Dry and Wet Cycle Time Ratio on the Corrosion Behavior of 2198 Aluminum-Lithium Alloy

SSRN

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SSRN 2024年

作者： Liu, Yingyan Deng, Zhibin Zhang, Qian Lu, Rui Yue, Hang Tang, Haiping Li, Guotao Civil Aviation Flight University of China Guanghan618307 China Civil Aircraft Fire Science and Safety Engineering Key Laboratory of Sichuan Province Guanghan618307 China Sichuan Key Technology Engineering Research Center for All-electric Navigable Aircraft Guanghan618307 China Petrochina Company Limited Yunnan671000 China

The corrosion behavior and mechanisms of 2198 aluminum-lithium alloy under alternating wet-dry conditions in a simulated marine atmospheric environment were investigated using weight loss measurement, electrochemical impedance spectroscopy (EIS), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), macroscopic morphology analysis, 3D profilometry, and X-ray photoelectron spectroscopy (XPS). The results indicate that corrosion weight loss increases with decreasing wet-to-dry ratios, accompanied by an increase in the corrosion rate. Various data suggest that the primary corrosion products are composed of Al2O3 AlO(OH), and AlCl3. The reduction in the wet-to-dry ratio leads to the enrichment of Cl- within the corrosion products, extending the contact time between the substrate and the medium, thereby intensifying the hydrolysis of Al3+. This exacerbates the dissolution at pitting sites, which in turn erodes and breaks down the corrosion product film, accelerating the overall corrosion process. © 2024, The Authors. All rights reserved.

关键词： Electrochemical impedance spectroscopy

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Taxi Time Prediction by Using Data Driven Approach:A New Perspective

SSRN

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SSRN 2022年

作者： Jiao, Qingyu Li, Nan Zheng, Zhigang Feng, Zan Qiang, Yigeng Chen, XinFeng China Academy of Civil Aviation Science and Technology China Civil Aviation Flight Wide Area Surveillance and Safety Control Technology Key Laboratory Civil Aviation University of China China College of Air Traffic Management Civil Aviation University of China China Northwest Air Traffic Administration of Civil Aviation of China China

Taxi time, as one of the key indicators to evaluate the airport operation efficiency, will not only have a direct impact on the takeoff and landing sequence of the runway, but also affect the operational efficiency of the airport. Nevertheless, previous research for taxi time prediction based on data-driven approach was mainly leveraged by regression algorithm, which rarely analyze the impact of uncertainty parameters on the accuracy of prediction, resulting in low utilization when the environment of the airport (such as traffic flow, runway configuration, etc.) changes. Hence, we proposed a deep learning model to predict taxi time based on dynamic parameters. First, according to the airport operation characteristics, parameters were divided into static parameters (aircraft type, taxiing distance, etc.) and dynamic parameters (airport traffic flow). Second, in order to capture the trend of the dynamic parameters, an attention mechanism based long-short-term memory combined with a deep neural network (D-LSTM) method is proposed to predict airport traffic flow. Last, a nested deep learning model that combined D-LSTM is established to predict the taxi time. We compare our new method with the state-of-the-art algorithms by using Hong Kong International Airport data, the result showed that the prediction accuracy of taxi-out time under nested deep learning model is 0.86 and the prediction accuracy of taxi-in is 0.90. In both cases, the prediction accuracy is significantly better than other algorithms. © 2022, The Authors. All rights reserved.

关键词： Efficiency

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A Wideband Dual Layer Frequency Selective Surface Shielding Screen

A Wideband Dual Layer Frequency Selective Surface Shielding ...

引用

International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Zhendong Bai Min Xu Lu Gao Jiaqi Liu National Key Laboratory of Science and Technology on Test Ph Beijing Institute of Space Long March Vehicle Beijing China Department of Aeronautical Engineering Army Aviation Institue Beijing China

A dual layer polarization and incident angle insensitive frequency selective surface (FSS) with wideband feature for electromagnetic shielding is presented in this paper. A single layer FR4 dielectric substrate is attached both sides with periodic copper pattern. The front layer comprises of combined square and circle loop and the background layer comprises of combined circle loops and strips. The proposed FSS exhibits a 11.2 GHz ultra-wide stop band response from 4.3 to 15.5 GHz. Because of the symmetry of the structure, the FSS is polarization insensitive. Numerical computation validates the incident angles stability up to 60° in TE modes.

关键词： Frequency selective surfaces Strips Resonant frequency Microwave ovens Stability analysis Copper Wideband

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Experimental Study on the Characteristics of Annular Fluid Film in a Locally Deformed Narrow Rectangular Channel

SSRN

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SSRN 2024年

作者： Wang, Fenze Ren, Quanyao Liu, Haidong Xiao, Yi Chen, Deqi Key Laboratory of Low-grade Energy Utilization Technologies and Systems Chongqing University Ministry of Education Chongqing400044 China Department of Nuclear Engineering and Technology School of Energy and Power Engineering Chongqing University Chongqing400044 China Science and Technology on Reactor System Design Technology Laboratory Chengdu610041 China Liangjiang International College Chongqing University of Technology Chongqing401135 China Chongqing Research Institute of HIT Chongqing401151 China School of Flight Technology Civil Aviation Flight University of China Sichuan618307 China China

The study of the characteristics of the annular flow film in the narrow rectangular channel under the localized deformation can provide a research basis for the heat and mass transfer and the hydrodynamic characteristics of the locally deformed narrow flow channel. In this study, the annular flow liquid film characterization experiments are carried out in a narrow rectangular channel without local deformation, ellipsoidal deformation and pillow-shaped deformation, and different annular flow liquid film parameters liquid film thickness, disturbance wave height, and disturbance wave wavelength are obtained by high-speed camera acquisition system and intelligent image processing technology. Analyze the effects of flow conditions and local deformation on the liquid film parameters of each annular flow. Local deformation impact factor functions for liquid film thickness, disturbance wave height, and disturbance wave wavelength are obtained. The error of the impact factor function is within ±30%. © 2024, The Authors. All rights reserved.

关键词： Liquid films

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Experimental Study on the Characteristics of Annular Fluid Film in a Locally Deformed Narrow Rectangular Channel

SSRN

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SSRN 2024年

The local deformation of plate fuel assembly due to neutron irradiation will lead to the deterioration of heat transfer in the flow channel. Studying the characteristics of annular flow films in narrow rectangular channels under localized deformation provides a foundation for understanding the heat and mass transfer and the hydrodynamic characteristics of the locally deformed narrow flow channel. In this study, the annular flow liquid film characterization experiments were conducted in a narrow rectangular channel under three conditions: no local deformation, ellipsoidal deformation, and pillow-shaped deformation. Various parameters of the annular flow liquid films, including liquid film thickness, disturbance wave height, and disturbance wave wavelength, were obtained using a high-speed camera acquisition system and advanced image processing techniques. The effects of flow conditions and local deformation on the liquid film parameters of each annular flow were analyzed. As the radial size of the local deformation increases relative to the liquid film thickness, the viscous bottom layer of the liquid film disintegrates, resulting in a reduction of the total liquid film thickness. When the gas-phase velocity is low, the local deformation exerts a greater shear force on the disturbance wave, prolonging the action time and increasing the likelihood of wave disintegration. Under conditions of no channel deformation, the disturbance wave wavelength is negatively correlated with the gas-phase velocity;conversely, under localized channel deformation, the wavelength is positively correlated with the gas-phase velocity. Thus, the effect of localized deformation on wavelength is bidirectional. Local deformation impact factor functions for liquid film thickness, disturbance wave height, and disturbance wave wavelength have been derived, with the error of these impact factor functions maintained within ±30%. © 2024, The Authors. All rights reserved.

关键词： Neutron irradiation

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