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International Conference on Microwave and Millimeter Wave technology Proceedings

作者： Chen Wang Jing Ma Bin Shi Zhong-bo Zhu Lin Peng The Key Laboratory of Microwave and Optical Wave Application Technology Guilin University of Electronic Technology Guilin Guangxi China The Science and Technology on Special System Simulation Laboratory Beijing Simulation Center Beijing China The National Key Laboratory of Science and Technology on Space Microwave Xi'an China

ISBN: (数字)9798350389968

ISBN: (纸本)9798350389975

In this paper, An ultra-wideband high gain circularly polarized all dielectric lens antenna is proposed. The lens antenna consists a linearly polarized horn and a dielectric lens with a gap. The impedance bandwidth, axial ratio and gain of the antenna can be improved by changing the shape of the lens. The PSO-GA is used to improve the design optimization efficiency of lens antenna, and the modeling time is shortened through the integrated modeling technology. The impedance bandwidth of the lens antenna is 40%, the maximum axial ratio is 2.8dB, and the maximum gain is 21.5dBic at 65GHz. In the 60-90GHz frequency band, the gain is greater than 20.5dBic.

关键词： Microwave antennas Polarization Shape Horn antennas simulation Bandwidth Ultra wideband antennas

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MD-TransUNet: TransUNet with Multi-attention and Dilated Convolution for Brain Stroke Lesion Segmentation 19th

MD-TransUNet: TransUNet with Multi-attention and Dilated C...

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19th EAI International Conference on Collaborative Computing: Networking, Applications and Worksharing, CollaborateCom 2023

作者： Xu, Jie Wan, Jian Zhang, Xin School of Computer Science and Technology Hangzhou Dianzi University Zhejiang310018 China Key Laboratory of Complex Systems Modeling and Simulation Ministry of Education Ministry of Education Beijing China School of Information and Electronic Engineering Zhejiang University of Science and Technology Zhejiang China Key Laboratory of Marine Ecosystem Dynamics Second Institute of Oceanography Ministry of Natural Resources Hangzhou China

ISBN: (纸本)9783031545276

The accurate segmentation of stroke lesion regions holds immense significance in shaping treatment strategies and rehabilitation protocols. Due to the large difference in the volume of stroke lesion areas and the great similarity between lesion areas and normal tissues, most of the existing methods for lesion segmentation cannot deal with these problems well. This paper proposes a novel network named MD-TransUNet for the segmentation of stroke lesions, whose framework is based on the UNet architecture. To fully obtain deep image features, it uses ResNet50 for downsampling. MD (multi-dilated) module is employed as the skip connection to gain more receptive fields. Different receptive fields can adapt to varying volumes of lesion areas. Then, a feature extraction module with multi-level attention mechanism is designed using ConvLSTM, non-local spatial attention, and channel attention modules to suppress useless information expression in skip connections and upsampling processes while focusing more on effective spatial and channel information in features. The experiments show that our proposed network gets superior performance than benchmark methods and indicates the generalization and effectiveness of the proposed model. © ICST Institute for Computer sciences, Social Informatics and Telecommunications Engineering 2024.

关键词： Convolution

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Availability Assessment of the LEO Satellite Communication System with the Consideration of Satellite Handover 14

Availability Assessment of the LEO Satellite Communication S...

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14th IEEE Global Reliability and Prognostics and Health Management Conference, PHM-Hangzhou 2023

作者： Tian, Yu Li, Ruiying Wang, Yuanyuan Ma, Ji Song, Yeqing School of Reliability and Systems Engineering Beihang University Beijing China Science and Technology on Reliability and Environmental Engineering Laboratory Beijing100191 China Deep Space Exploration Laboratory Beijing100194 China

ISBN: (纸本)9798350301359

Satellite handover frequently occurs on low-earth-orbit (LEO) satellite communication systems, and it affects system availability. However, existing studies neglected such an impact. To solve the problem above, this paper proposed a topology modeling method, in which the satellite dynamic operation is divided into small time slices to simplify the system, and the earth ground is divided into grids to abstract the ground user's communication requirement. Then, the service availability is defined according to the key performance parameter of the communication service, delay, and a Monte Carlo-based availability assessment method is addressed with the consideration of the satellite handover. Finally, a case is used to analyze how satellite handover strategies affect service availability. and suggestions are given to improve system availability. © 2023 IEEE.

关键词： low-earth-orbit satellite communication system Monte Carlo satellite handover service availability

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Cache-Assisted Task Offloading and Resource Optimization for LEO Network 22

Cache-Assisted Task Offloading and Resource Optimization for...

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22nd International Conference on Optical Communications and Networks, ICOCN 2024

作者： Chai, Furong Zhang, Qi Xin, Xiangjun Wang, Yanxiang Li, Yuanfeng Sun, Meng Sun, Dandan Tian, Feng Tian, Qinghua Wang, Yongjun Yang, Leijing Wang, Fu Zhou, Sitong Beijing100876 China Beijing Key Laboratory of Space-ground Interconnection and Convergence BUPT Beijing100876 China Science and Technology on Information Systems Engineering Laboratory National Univ. of Defense Technology Changsha410073 China School of Information and Electronics Beijing Institute of Technology Beijing100081 China

We proposed a cache-assisted task offloading and resource allocation model and a deep reinforcement learning (DRL) based method for low-earth orbit (LEO) network. Our method takes obvious advantages in reducing delay ... 详细信息

ISBN: (纸本)9798350367652

关键词： Deep reinforcement learning

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User-level failure detection and auto-recovery of parallel programs in HPC systems

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Frontiers of Computer science 2021年第6期15卷 31-42页

作者： Guozhen ZHANG Yi LIU Hailong YANG Jun XU Depei QIAN State Key Laboratory of Software Development Environment Beijing 100191China Sino-German Joint Software Institute Beihang UniversityBeijing 100191China School of Computer Science and Engineering Beihang UniversityBeijing 100191China Science and Technology on Space System Simulation Laboratory Beijing Simulation Center Beijing 100854China

As the mean-time-between-failures(MTBF)continues to decline with the increasing number of components on large-scale high performance computing(HPC)systems,program failures might occur during the execution period with high *** successful execution of the HPC programs has become an issue that the unprivileged users should be *** the user perspective,if the program failure cannot be detected and handled in time,it would waste resources and delay the progress of program ***,the unprivileged users are unable to perform program state checking due to execution control by the job management system as well as the limited ***,automated tools for supporting user-level failure detection and autorecovery of parallel programs in HPC systems are *** paper proposes an innovative method for the unprivileged user to achieve failure detection of job execution and automatic resubmission of failed *** state checker in our method is encapsulated as an independent job to reduce interference with the user *** addition,we propose a dual-checker mechanism to improve the robustness of our *** implement the proposed method as a tool named automatic re-launcher(ARL)and evaluate it on the Tianhe-2 *** results show that ARL can detect the execution failures effectively on Tianhe-2 *** addition,the communication and performance overhead caused by ARL is *** good scalability of ARL makes it applicable for large-scale HPC systems.

关键词： high performance computing parallel program failure detection failure auto-recovery

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Satellite Interference Signal Classification Using Improved MLP Model

Satellite Interference Signal Classification Using Improved ...

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2022 IEEE International Conference on Unmanned systems, ICUS 2022

作者： Xie, Liwei Zhuang, Yaqiang Zhuang, Xuebin Zeng, Xiaohui School of Systems Science and Engineering Sun Yat-Sen University Guangzhou China School of Integrated Circuits and Electronics Beijing Institute of Technology Beijing Key Laboratory of Millimeter Wave and Terahertz Technology Beijing China Science and Technology On Complex Aviation Systems Simulation Laboratory Beijing China

ISBN: (数字)9781665484565

ISBN: (纸本)9781665484565

In response to the existing style of deceptive jamming of Global Position System (GPS) receivers by aerial jammer carriers, a method using improved multi-layer perceptron (MLP) model is proposed to identify and classify interference sources based on the rate of change of satellite incoming angle. The work firstly constructs an airborne GPS interference source localization deployment model, then analyzes and verifies the rationality of this simulation data model, and finally emphasizes the superiority of the proposed method using the classical classification algorithm as a comparison method. The simulation results indicated that the proposed method is capable to identify the corresponding interferers with a greater rate of recognition compared with other method in the built multi-interference source environment, which provides a reference for dealing with the interference identification and classification in the networked GPS interference source deployment environment. © 2022 IEEE.

关键词： Antennas

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A Hybrid Ant Colony Optimization and Tabu Search Algorithm for Routing Optimization in LEO Satellite Networks 22

A Hybrid Ant Colony Optimization and Tabu Search Algorithm f...

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22nd International Conference on Optical Communications and Networks, ICOCN 2024

作者： Xu, Yifan Li, Yuanfeng Zhang, Qi Sun, Meng Feng, Weiying Li, Xiaohu Zhao, Yi Chai, Furong Tian, Feng Wang, Fu Tian, Qinghua Yang, Leijing Wang, Yongjun Beijing100876 China BUPT Beijing Key Laboratory of Space-ground Interconnection and Convergence Beijing100876 China National University of Defense Technology Science and Technology on Information Systems Engineering Laboratory Changsha410073 China School of Materials Science and Engineering Beihang University Beijing100191 China Beijing Institute of Control and Electronic Technology Beijing100038 China

To optimize routing costs and communication delays in LEO satellite networks, a hybrid ACO and tabu search algorithm is proposed. simulation results shows compared to the original ACO algorithm, it reduced routing cos... 详细信息

ISBN: (纸本)9798350367652

关键词： Ant colony optimization

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On-Chip Wideband Bandpass Filter with High Frequency Selectivity and Low Insertion Loss Based on GaAs Integrated Passive Device technology

On-Chip Wideband Bandpass Filter with High Frequency Selecti...

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2023 IEEE MTT-S International Wireless Symposium, IWS 2023

作者： Dong, Jiancheng Zhu, Xu Yang, Tao Nie, Yi Wang, Yong Research Center of Advanced Rf Chips and Systems Nanhu Laboratory Jiaxing314001 China Laboratory of Electromagnetic Space Cognition and Intelligent Control Technology Beijing100191 China University of Electronic Science and Technology of China Chengdu611731 China

ISBN: (纸本)9798350336535

In this paper, an on-chip wideband bandpass filter (BPF) with high frequency selectivity and low insertion loss is proposed using gallium arsenide (GaAs) integrated passive device (IPD) technology. Multiple transmission zeros can be provided by the capacitors loaded on the series and parallel LC resonators for the proposed design. Comparing with the state-of-the-art on-chip wideband BPFs, the proposed design has the advantages of high frequency selectivity and low loss. The final filter centered at 1.93 GHz with the 3-dB fractional bandwidth of 64.2% is demonstrated, which exhibits the excellent shape factor (30-dB BW/3-dB BW) of 1.28 and the minimum insertion loss of 1.17 dB. © 2023 IEEE.

关键词： Gallium arsenide

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Analysis of node importance of satellite network based on triangular motif 23

Analysis of node importance of satellite network based on tr...

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Proceedings of the 2023 International Conference on Communication Network and Machine Learning

作者： Zhongmin Pei Boren Hu Zhangkai Luo Jie Ding Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University China Department of Electronics and Optical Engineering Space Engineering University China

ISBN: (纸本)9798400716683

Motif provides a local high-order substructure angle for the analysis of network structure evolution, which is of great significance for the study of the interaction between satellite network structure and function. Taking the time scrambling null motif in steady state as a reference, the stability analysis of satellite network structure is carried out from the perspective of the local structure of the motif characteristics; define the temporal degree of satellite network, and propose a satellite network node importance analysis method based on the number of node-constructed triangle motifs, and compare the changes of motifs characteristics under the deliberate attack of temporal degree and based on triangle motifs. simulation experiments are conducted on 46-node GPS constellations containing satellites and ground stations, and it is found that the network with higher initial triangle concentration showed higher stability. In GPS satellite network where the number of node triangle motif is positively correlated with their temporal degree, the attack strategy based on the triangle motif accelerates the attenuation of the triangle subgraph, and the node importance analysis method of the satellite network has higher accuracy.

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Research on Requirement Analysis Method of space Equipment technology System based on capability

Research on Requirement Analysis Method of Space Equipment T...

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IEEE Information technology and Mechatronics Engineering Conference (ITOEC)

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

"Demand traction and technology promotion" is the main law of equipment system construction and development. Scientific determination and quantitative evaluation of key technologies in the field of military equipment is the key and difficult point of system macro demonstration. Based on the analysis of the technical structure of space information equipment technology, this paper proposes a capability-based requirement analysis framework and process of space information equipment technology system, establishes a requirement analysis model of technology system, and constructs its technical system by taking space situation awareness system as an example. It provides technical basis for the requirement analysis of space information equipment technology system.

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