检索结果-内蒙古大学图书馆

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

来源：评论

学校读者我要写书评

暂无评论

Real-Time Path Planning based on the Lock Loss Model

Real-Time Path Planning based on the Lock Loss Model

引用

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

作者： Luo, Xun Liu, Li Liu, Xin National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematical Beijing China China Academy of Launch Vehicle Technology Beijing China

ISBN: (纸本)9781665452366

A new method of aircraft low altitude penetration is proposed with temporal constraints that allow periods of high observability interspersed with periods of low observability. The aircraft's RCS character is simplified into the 'bow-tie' distribution, then the aircraft can dynamically adjust its yaw angle to minimize the risk from the radars. According to the modified Lock Loss model and the TWS(Track While Scan) radar work flow, and real-time evaluating model on the original path, a fast real-time path planning method is present on the situation that unexpected threats occur. An example of real-time path planning is given. © 2022 IEEE.

关键词： Locks (fasteners)

来源：评论

学校读者我要写书评

暂无评论

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

Electromagnetic Computational Modeling and Bistatic Scatteri...

引用

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

来源：评论

学校读者我要写书评

暂无评论

A novel GCV-based criterion for parametric PSF estimation 12

A novel GCV-based criterion for parametric PSF estimation

引用

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

来源：评论

学校读者我要写书评

暂无评论

Frequency divided adaptive Kalman filter in guidance law recognition 24

Frequency divided adaptive Kalman filter in guidance law rec...

引用

24th European Navigation Conference, ENC 2016

作者： Run-Le, Du Jia-Qi, Liu Zhi-Feng, Li Zhen-Hong, Niu National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

ISBN: (纸本)9781479989157

Recognition of guidance law on non-cooperative vehicle is drawing research interest among the literature, while insufficient accuracy of modeling and measurement makes it a hard problem. In this paper, a Frequency Divided Adaptive Kalman Filter is proposed to implement guidance law recognition. In FD-AKF, a Low Pass Filter is applied to extract the noise directly from state vector and measurement vector, and estimate the co-variance matrices of observation noise and prediction noise online. Without intertwined iterating equation of prediction noise and observation noise, FD-AKF decouples the estimation on prediction noise and observation noise, and thus avoids the risk of bias and divergence. Simulation results show that, FD-AKF improves robustness of guidance recognition significantly over Kalman Filter and Sage-Husa. © 2016 IEEE.

关键词： Forecasting

来源：评论

学校读者我要写书评

暂无评论

Fast data fusion algorithm for building navigation base in formation flying

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

Study of RF structure and Beam Wave Interaction system for a W-band Sheet Beam EIK

Study of RF structure and Beam Wave Interaction system for a...

引用

2017 International Conference on Radar Systems, Radar 2017

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

ISBN: (纸本)9781785615153

Sheet beam Extended Interaction Klystron (EIK) is an attractive Millimeter Waves (MMW) amplifier because of its high gain per unit length and compact configuration, which can be used in radar transmission system. In this paper, RF structure and beam wave interaction system of W band sheet beam EIK has been designed. A new and effective method of designing and studying the beam wave interaction system is presented in this *** whole tube consists of one single-gap cavity, six tri-gaps cavities and one five-gaps cavity. By optimizing the position of cavities, the output power can achieve 30 kW and high gain of 50 dB, which is calculated by three dimensional particle in cell (3D-PIC)*** provides a powerful basis for the subsequent study of sheet beam EIK. © 2017 Institution of Engineering and technology. All rights reserved.

关键词： Millimeter waves

来源：评论

学校读者我要写书评

暂无评论

Study of RF structure for W band sheet beam EIK

Study of RF structure for W band sheet beam EIK

引用

IET International Radar Conference 2015

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

ISBN: (纸本)9781849199940

Microwave tubes are vacuum electron devices used for the generation and amplification of radio frequencies in the microwave frequency range. Klystron is a kind of microwave tubes which is used in radar. A sheet-beam Extended Interaction Klystron (SBEIK) is an attractive MMW amplifier because of its high gain per unit length and compact configuration. The RF structure is an important part of the whole tube, which is used for beam wave interaction. In this paper, two kinds of barbell cavity has been studied. The difference between the separating multi-gap barbell resonant cavity and the strong coupling multi-gap barbell cavity has been discussed. RF parameters have been calculated by 3D simulations.

关键词： Microwaves

来源：评论

学校读者我要写书评

暂无评论

Exact Decoding of Repetition Code under Circuit Level Noise

arXiv

引用

arXiv 2025年

作者： Cao, Hanyan Zhao, Shoukuan Feng, Dongyang Shen, Zisong Yan, Haisheng Su, Tang Sun, Weijie Xu, Huikai Pan, Feng Yu, Haifeng Zhang, Pan CAS Key Laboratory for Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing100190 China School of Physical Sciences University of Chinese Academy of Sciences Beijing100049 China Beijing Academy of Quantum Information Sciences Beijing100193 China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study UCAS Hangzhou310024 China Centre for Quantum Technologies National University of Singapore 117543 Singapore Science Mathematics and Technology Cluster Singapore University of Technology and Design 8 Somapah Road 487372 Singapore Hefei National Laboratory Hefei230088 China

Repetition code forms a fundamental basis for quantum error correction experiments. To date, it stands as the sole code that has achieved large distances and extremely low error rates. Its applications span the spectrum of evaluating hardware limitations, pinpointing hardware defects, and detecting rare events. However, current methods for decoding repetition codes under circuit level noise are suboptimal, leading to inaccurate error correction thresholds and introducing additional errors in event detection. In this work, we establish that repetition code under circuit level noise has an exact solution, and we propose an optimal maximum likelihood decoding algorithm called Planar . The algorithm is based on the exact solution of the spin glass partition function on planar graphs and has polynomial computational complexity. Through extensive numerical experiments, we demonstrate that our algorithm uncovers the exact threshold for depolarizing noise and realistic superconductor SI1000 noise. Furthermore, we apply our method to analyze data from recent quantum memory experiments conducted by Google Quantum AI, revealing that part of the error floor was attributed to the decoding algorithm used by Google. Finally, we implemented the repetition code quantum memory on superconducting systems with a 72-qubit quantum chip lacking reset gates, demonstrating that even with an unknown error model, the proposed algorithm achieves a significantly lower logical error rate than the matching-based algorithm. © 2025, CC BY.

关键词： Spin glass

来源：评论

学校读者我要写书评

暂无评论

Experimental Studies of Low-Pressure Plasma Jet by Means of Langmuir Probes and Emission Spectra

引用

Plasma science and technology 2009年第3期11卷 307-313页

作者：刘磊曹金祥牛田野王亮孟刚刘鑫袁雷邬润辉张生俊任爱民 Key Laboratory of Basic Plasma Physics Chinese Academy of Sciencesand Department of Modern PhysicsUniversity of Science and Technology of China China Academy of Space Technology Test Physics & Numerical Mathematics Laboratory

An investigation was made into the argon plasma jet that expanded in a low-pressure vacuum chamber. The spatial distributions of the parameters of the plasma jet with different supplied powers were measured using a ten-channel Langmuir probe array. The chemical species in the plasma jet were identified by emission spectroscopy. The electron excitation temperatures at two positions, 10 cm and 50 cm downstream from the nozzle exit were calculated, respectively, by the Boltzmann plot method.

关键词： plasma jet spatial distribution probe array emission spectrum

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：