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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Zhu, Zihui Cai, Wenlin Li, Jianhua Xue, Feng Gao, Lu Liu, Jiaqi National Key Laboratory Science and Technology on Test Physics and Numerical Mathematics Beijing China

ISBN: (纸本)9781665452366

Real-time semantic segmentation of street view images can be used as a visual aid system during autonomous driving. This paper proposes a multi-branch cross-layer fusion network (MCFNet). The model uses a multi-branch network to extract features, fuses the features of different stages of multiple branches for prediction, and uses a lightweight depthwise separable convolution to reduce the amount of computation. We use the Cityscapes dataset to train and evaluate the algorithm and get 61.6% mIoU and 115.3 fps. © 2022 IEEE.

关键词： Convolution

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Near-field Measurement Method for Electromagnetic Scattering of Electrically Large-scale Plasma

Near-field Measurement Method for Electromagnetic Scattering...

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Liu, Jiaqi Gao, Lu Wu, Runhui Ai, Xia Chai, Song Liu, Xin Zhang, Shengjun Cui, Yichun National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing China

ISBN: (纸本)9781665452366

In the near-field test environment of 01500×3300mm vacuum vessel with low electromagnetic scattering, the relative measurement method is used, that is, the results of electrically large-scale plasma radar cross section (RCS) are extrapolated by measuring the ratio of standard volume echo energy to plasma echo energy. © 2022 IEEE.

关键词： Radar cross section

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A Triple-layer Frequency Selective Surface with Flat Wide Passband 5

A Triple-layer Frequency Selective Surface with Flat Wide Pa...

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5th IEEE International Conference on Computational Electromagnetics, ICCEM 2019

作者： Cui, Yichun Zhang, Shengjun Wang, Mingliang National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

ISBN: (纸本)9781538671115

In this paper, a novel triple-layer band-pass Frequency selective surface (FSS) with wide passband and low insertion loss is proposed. The proposed FSS is composed of three FSS layers and two dielectric substrates which are symmetric vertically. This structure realizes a three-order response and wide stop band with steep falling edge. Equivalent circuit analysis indicates that the three-order response is generated by resonance of FSS layers and coupling between layers, respectively. After optimization, the passband of proposed FSS ranges from 7.728GHz to 12.31GHz, whose fractional bandwidth reaches 44.5% with -0.044dB insertion loss. Meanwhile, this FSS has stable performance for TE polarization under oblique incidence. © 2019 IEEE.

关键词： Frequency selective surfaces

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Optimal selection of regularization parameter for 1-based image restoration based on SURE

Optimal selection of regularization parameter for 1-based im...

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International Symposium on Infrared technology and Application and the International Symposiums on Robot Sensing and Advanced Control

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

ISBN: (纸本)9781510607729

To exploit the sparsity in transform domain (e.g. wavelets), the image deconvolution can be typically formulated as a 1-penalized minimization problem, which, however, generally requires proper selection of regularization parameter for desired reconstruction quality. The key contribution of this paper is to develop a novel data-driven scheme to optimize regularization parameter, such that the resultant restored image achieves minimum prediction error (p-error). First, we develop Stein's unbiased risk estimate (SURE), an unbiased estimate of p-error, for image degradation model. Then, we propose a recursive evaluation of SURE for the basic iterative shrinkage/thresholding (IST), which enables us to find the optimal value of regularization parameter by exhaustive search. The numerical experiments show that the proposed SURE-based optimization leads to nearly optimal deconvolution performance in terms of peak signal-to-noise ratio (PSNR). © 2016 SPIE.

关键词： Image reconstruction

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Communication performance optimization of spaceborne/airborne Radar networks

Communication performance optimization of spaceborne/airborn...

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IET International Radar Conference 2015

作者： Li, Hu Gao, Lu Liu, Jiaqi Liu, Hongyan Jiang, Zhiye Bai, Jinliang Xu, Feng Chen, Shuyuan Liu, Shengdong Zhu, Guangsheng Liu, Xuemei National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

ISBN: (纸本)9781849199940

In this paper, we investigate communication performance optimization problem of spaceborne/airborne Radar networks. A model of spaceborne/airborne Radar networks with propagation delay and power constraints is given first. A Quadric Lyapunov function based Algorithm (QLA) is then proposed aiming at greedily minimizing an expression containing Lyapunov drift. We prove two main conclusions, one is that the communication network of spaceborne/airborne Radars under QLA is stable, the other is that power constraints are met. Upper bounds of queue backlogs and a lower bound of utility function are established through theoretical analysis, and how propagation delay jeopardizes utility performance is also demonstrated. Simulation of QLA is carried out in a scenario consists of 6 nodes, and results are in accordance with theoretical conclusions.

关键词： Lyapunov methods

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A New Criterion For Optimization Of Total Variation Denoising

A New Criterion For Optimization Of Total Variation Denoisin...

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Xue, Feng Ai, Xia Gao, Lu Liu, Jiaqi National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

ISBN: (纸本)9781665452366

Based on Chambolle's algorithm, we develop a data-driven optimization scheme based on minimization of Stein's unbiased risk estimate (SURE) - statistically equivalent to mean squared error (MSE). We propose a recursive evaluation of SURE to monitor the estimation error during Chambolle's iteration;the optimal value is then identified by the minimum SURE. We exemplify the proposed methods with 1-D signal denoising. © 2022 IEEE.

关键词： Iterative methods

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A novel GCV-based criterion for parametric PSF estimation 12

A novel GCV-based criterion for parametric PSF estimation

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2014 12th IEEE International Conference on Signal Processing, ICSP 2014

作者： Xue, Feng Liu, Jiaqi Li, Zhifeng Meng, Gang National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

ISBN: (纸本)9781479921881

We propose a generalized cross validation (GCV) as a novel criterion for estimating a point spread function (PSF) from the degraded image only. The PSF is obtained by minimizing this new objective functional over a family of Wiener processings. Based on this estimated PSF, we then perform deconvolution using our recently developed SURE-LET algorithm. The GCV-based criterion is exemplified with a number of parametric PSF, involving a scaling factor that controls the blur size. A typical example of such parametrization is the Gaussian kernel. The experimental results demonstrate that the GCV minimization yields highly accurate estimates of the PSF parameters, which also result in a negligible loss of visual quality, compared to that obtained with the exact PSF. The highly competitive results outline the great potential of developing more powerful blind deconvolution algorithms based on this criterion. © 2014 IEEE.

关键词： Optical transfer function

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Thermodynamic nonequilibrium effects in three-dimensional high-speed compressible flows: Multiscale modeling and simulation via the discrete Boltzmann method

arXiv

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arXiv 2025年

作者： Guo, Qinghong Gan, Yanbiao Yang, Bin Wu, Yanhong Lai, Huilin Xu, Aiguo Fujian Normal University Fuzhou350117 China Hebei Key Laboratory of Trans-Media Aerial Underwater Vehicle North China Institute of Aerospace Engineering Langfang065000 China School of Energy and Safety Engineering Tianjin Chengjian University Tianjin300384 China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics P. O. Box 8009-26 Beijing100088 China National Key Laboratory of Shock Wave and Detonation Physics Mianyang621999 China HEDPS Center for Applied Physics and Technology College of Engineering Peking University Beijing100871 China State Key Laboratory of Explosion Science and Safety Protection Beijing Institute of Technology Beijing100081 China

Three-dimensional (3D) high-speed compressible flow is a typical nonlinear, nonequilibrium, and multiscale complex flow. Traditional fluid mechanics models, based on the quasi-continuum assumption and near-equilibrium approximation, are insufficient to capture significant discrete effects and thermodynamic nonequilibrium effects (TNEs) as the Knudsen number increases. To overcome these limitations, a discrete Boltzmann modeling and simulation method, rooted in kinetic and mean-field theories, has been developed. By applying Chapman-Enskog multiscale analysis, the essential kinetic moment relations Φ = (M0,M1,M2,0,M2,M3,1,M3,M4,2,M4,M5,3) for characterizing second-order TNEs are determined. These relations Φ are invariants in coarse-grained physical modeling, providing a unique mesoscopic perspective for analyzing TNE behaviors. A discrete Boltzmann model, accurate to second-order in the Knudsen number, is developed to enable multiscale simulations of 3D supersonic flows. As key TNE measures, nonlinear constitutive relations (NCRs), are theoretically derived for the 3D case, offering a constitutive foundation for improving macroscopic fluid modeling. The NCRs in three dimensions exhibit greater complexity than their two-dimensional counterparts. This complexity arises from increased degrees of freedom, which introduce additional kinds of nonequilibrium driving forces, stronger coupling between these forces, and a significant increase in nonequilibrium components. At the macroscopic level, the model is validated through a series of classical test cases, ranging from one-dimensional to 3D scenarios, from subsonic to supersonic regimes. At the mesoscopic level, the model accurately captures typical TNEs, such as viscous stress and heat flux, around mesoscale structures, across various scales and orders. This work provides kinetic insights that advance multiscale simulation techniques for 3D high-speed compressible flows. Copyright © 2025, The Authors. All rights reserve

关键词： Compressible flow

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Electromagnetic Computational Modeling and Bistatic Scattering Characteristics Analysis of Spherical Jammer Group

Electromagnetic Computational Modeling and Bistatic Scatteri...

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2024 International Conference on Intelligent Communication, Sensing and Electromagnetics, ICSE 2024

作者： Xin, Wei Liu, Xin Wang, Weidong National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing187023 China

ISBN: (纸本)9798350354935

Bistatic radar is widely used in the military field with its good anti-jammer ability and accurate detection and identification ability. How to implement effective jammer for this kind of radar system has become a research hotspot at present. Due to the small scattering intensity and weak echo energy of j ammer monomer, it has no advantage in countering the bistatic radar. It is necessary to release multiple jammers to form a group to form strong scattering, so as to interfere with the bistatic radar to detect and recognize the target, so the study on the scattering characteristics of the jammer group is particularly important. Therefore, this paper takes the group composed of spherical monomer as an example, first of all, MATLAB and CST STUDIO SUITE (CST) are used for joint modeling, and then electromagnetic simulation calculation is carried out on the group of spherical jammer objects with different bands, different sphere sizes, different group densities and different group distributions to analyze the bistatic scattering characteristics under different parameters. The research results show that the four parameters will have different degrees of influence on the bistatic scattering characteristics of the spherical jammer group, which provides a theoretical basis and data support for parameter selection and airspace planning against the bistatic radar. © 2024 IEEE.

关键词： Spheres

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Fast data fusion algorithm for building navigation base in formation flying

Fast data fusion algorithm for building navigation base in f...

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19th International Conference on Automation and Computing, ICAC 2013

作者： Du, Runle Liu, Jiaqi Jiang, Zhiye Liu, Guojuan National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing 100076 China

ISBN: (纸本)9781908549082

When multiple miniature vehicles with inter-vehicle distance measurement ability collaborate in a formation, navigation base can be established without external assisting systems. Shared navigation data is fused to compensate the drift of navigation system and the noise from distance measurement. Existing algorithms like Least Squared Error (LSE) can process nonlinear measurements at high speed, but the noise level of result is high. Kalman Filtering can achieve lower noise level, but it needs huge amount of calculation. The amount of calculation rendered it unsuitable for onboard computing systems. To reduce the computation load of the data fusion algorithm and maintain high precision, Fast Data Fusion (FDF) algorithm which combines LSE and KF is proposed. In this algorithm, LSE is used as the preprocessing stage to build a coarse estimation and KF is then used to further alleviate noises in the pre-processed estimations. In FDF, the dynamic model can be much simpler than KF, so the computation load is reduced while the result still has the advantage of high precision. Simulation results show that, proposed method uses no more than 2.5% of computation time of Kalman Filtering and achieved matching precision. © 2013 Chinese Automation and Computing Society in the UK - CACS.

关键词： Navigation systems

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