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THE FAST FIXED-POINT ALGORITHM FOR SPECKLE REDUCTION OF POLARIMETRIC SAR IMAGE
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作者 FuYusheng ChertXiaoning PiYiming HouYinming 《Journal of Electronics(China)》 2005年第3期288-293,共6页
In this letter, a simple and efficient method of image speckle reduction for polari- metric SAR is put forward. It is based on the fast fixed-point ICA (Independent Component Analysis) algorithm of orthogonal and symm... In this letter, a simple and efficient method of image speckle reduction for polari- metric SAR is put forward. It is based on the fast fixed-point ICA (Independent Component Analysis) algorithm of orthogonal and symmetric matrix. Simulation experiment is carried out to separate speckle noise from the polarimetric SAR images, and it indicates that this algorithm has high convergency speed and stability, the image speckle noise is reduced effectively and the speckle index is low, and the image quality is improved obviously. 展开更多
关键词 SAR fast fixed-point Independent Component Analysis (ICA) Principal Com- ponent Analysis (PCA) KURTOSIS SPECKLE
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基于自适应阈值的型钢精确角点FAST检测算法
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作者 包家汉 孙德尚 +1 位作者 黄建中 胡政 《上海交通大学学报》 北大核心 2025年第5期691-702,共12页
基于机器视觉的在线型钢平直度检测中,对型钢图像关键角点快速、准确地提取是实现精确检测的关键技术问题.针对加速分割检验特征提取(FAST)算法需要人工设定角点筛选阈值和角点提取存在大量伪角点的问题,提出一种自适应阈值生成及校正策... 基于机器视觉的在线型钢平直度检测中,对型钢图像关键角点快速、准确地提取是实现精确检测的关键技术问题.针对加速分割检验特征提取(FAST)算法需要人工设定角点筛选阈值和角点提取存在大量伪角点的问题,提出一种自适应阈值生成及校正策略,能够在自动获取初始阈值的基础上,根据角点数是否达到初始角点集要求对阈值实时校正直至达到适当值,以减少关键角点遗漏.在采用FAST提取角点的基础上,利用最小核心值相似区域(SUSAN)算法剔除伪角点,以保证关键角点提取的有效性.试验证明,这种基于自适应阈值的FAST角点检测算法(FAST-A),在检测环境和对象特性发生变化时,仍然可以准确、快速地检测到型钢关键角点,在为型钢平直度检测实时提供精确角点的基础上,提高角点提取的自适应性. 展开更多
关键词 型钢 角点检测 加速分割检验特征提取算法 最小核心值相似区域算法 自适应阈值
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Sparse-Grid Implementation of Fixed-Point Fast Sweeping WENO Schemes for Eikonal Equations
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作者 Zachary M.Miksis Yong-Tao Zhang 《Communications on Applied Mathematics and Computation》 EI 2024年第1期3-29,共27页
Fixed-point fast sweeping methods are a class of explicit iterative methods developed in the literature to efficiently solve steady-state solutions of hyperbolic partial differential equations(PDEs).As other types of ... Fixed-point fast sweeping methods are a class of explicit iterative methods developed in the literature to efficiently solve steady-state solutions of hyperbolic partial differential equations(PDEs).As other types of fast sweeping schemes,fixed-point fast sweeping methods use the Gauss-Seidel iterations and alternating sweeping strategy to cover characteristics of hyperbolic PDEs in a certain direction simultaneously in each sweeping order.The resulting iterative schemes have a fast convergence rate to steady-state solutions.Moreover,an advantage of fixed-point fast sweeping methods over other types of fast sweeping methods is that they are explicit and do not involve the inverse operation of any nonlinear local system.Hence,they are robust and flexible,and have been combined with high-order accurate weighted essentially non-oscillatory(WENO)schemes to solve various hyperbolic PDEs in the literature.For multidimensional nonlinear problems,high-order fixed-point fast sweeping WENO methods still require quite a large amount of computational costs.In this technical note,we apply sparse-grid techniques,an effective approximation tool for multidimensional problems,to fixed-point fast sweeping WENO methods for reducing their computational costs.Here,we focus on fixed-point fast sweeping WENO schemes with third-order accuracy(Zhang et al.2006[41]),for solving Eikonal equations,an important class of static Hamilton-Jacobi(H-J)equations.Numerical experiments on solving multidimensional Eikonal equations and a more general static H-J equation are performed to show that the sparse-grid computations of the fixed-point fast sweeping WENO schemes achieve large savings of CPU times on refined meshes,and at the same time maintain comparable accuracy and resolution with those on corresponding regular single grids. 展开更多
关键词 fixed-point fast sweeping methods Weighted essentially non-oscillatory(WENO)schemes Sparse grids Static Hamilton-Jacobi(H-J)equations Eikonal equations
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Improving path planning efficiency for underwater gravity-aided navigation based on a new depth sorting fast search algorithm
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作者 Xiaocong Zhou Wei Zheng +2 位作者 Zhaowei Li Panlong Wu Yongjin Sun 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期285-296,共12页
This study focuses on the improvement of path planning efficiency for underwater gravity-aided navigation.Firstly,a Depth Sorting Fast Search(DSFS)algorithm was proposed to improve the planning speed of the Quick Rapi... This study focuses on the improvement of path planning efficiency for underwater gravity-aided navigation.Firstly,a Depth Sorting Fast Search(DSFS)algorithm was proposed to improve the planning speed of the Quick Rapidly-exploring Random Trees*(Q-RRT*)algorithm.A cost inequality relationship between an ancestor and its descendants was derived,and the ancestors were filtered accordingly.Secondly,the underwater gravity-aided navigation path planning system was designed based on the DSFS algorithm,taking into account the fitness,safety,and asymptotic optimality of the routes,according to the gravity suitability distribution of the navigation space.Finally,experimental comparisons of the computing performance of the ChooseParent procedure,the Rewire procedure,and the combination of the two procedures for Q-RRT*and DSFS were conducted under the same planning environment and parameter conditions,respectively.The results showed that the computational efficiency of the DSFS algorithm was improved by about 1.2 times compared with the Q-RRT*algorithm while ensuring correct computational results. 展开更多
关键词 Depth Sorting fast Search algorithm Underwater gravity-aided navigation Path planning efficiency Quick Rapidly-exploring Random Trees*(QRRT*)
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基于改进Canny-FAST算法的折叠翼几何尺寸自动化测量
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作者 蔡引娣 孙梓盟 +3 位作者 李世雄 牛超 葛太坤 高鑫巍 《光学精密工程》 北大核心 2025年第3期466-475,共10页
为了实现非标复杂构件折叠翼几何尺寸的高精度、高效率测量,提出一种基于改进Canny-FAST算法的折叠翼几何尺寸自动化测量方法,解决了传统人工测量方法存在的测量精度低、重复性差及效率低等问题。通过在传统CannyFAST算法中引入Douglas-... 为了实现非标复杂构件折叠翼几何尺寸的高精度、高效率测量,提出一种基于改进Canny-FAST算法的折叠翼几何尺寸自动化测量方法,解决了传统人工测量方法存在的测量精度低、重复性差及效率低等问题。通过在传统CannyFAST算法中引入Douglas-Peucker算法的方式以简化折叠翼轮廓特征,解决了传统Canny-FAST算法在提取特征复杂轮廓角点时提取精度低、稳定性不好等问题,提高了折叠翼几何尺寸的测量精度。基于提出方法研制了折叠翼几何尺寸自动化测量系统,通过建立该系统中测量模块和运动模块的自动交互通讯,实现折叠翼几何尺寸高精度、高稳定性和高效率的自动化测量。经实验表明,自研的折叠翼几何尺寸自动化测量系统长度测量精度优于65μm,角度测量精度优于0.049°,满足折叠翼几何尺寸测量精度要求。 展开更多
关键词 折叠翼 图像拼接 自动化 Canny-fast算法 DOUGLAS-PEUCKER算法
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基于Fast ICA算法的供水管网漏失量估算
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作者 赵桓 吕谋 +1 位作者 刘志壮 王兴 《中国给水排水》 北大核心 2025年第15期91-96,共6页
针对日益严峻的城镇供水管网漏损问题,对漏失量与用户水量的变化特征及源信号相互独立特征进行深入分析,并基于Fast ICA算法建立漏失量估算模型,对观测漏失信号进行白化处理、寻优迭代及信号幅值还原;然后,以北方某生活小区为研究区域,... 针对日益严峻的城镇供水管网漏损问题,对漏失量与用户水量的变化特征及源信号相互独立特征进行深入分析,并基于Fast ICA算法建立漏失量估算模型,对观测漏失信号进行白化处理、寻优迭代及信号幅值还原;然后,以北方某生活小区为研究区域,构建供水管网实验模型,在实验室条件下验证Fast ICA算法用于管网漏失量估算的可行性;最后,将Fast ICA漏失量估算模型应用于DS山庄工程实例的供水管网漏失分析中,并与小波变换理论在实际供水环境下的适用性进行比较。结果表明,与小波变换算法相比,Fast ICA模型计算出的漏失量与真实漏失量相对误差更小,变化趋势相似性更高。 展开更多
关键词 供水管网 盲源分离 fast ICA算法 小波变换 漏失量估算
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基于多目标FAST算法的超声滚挤压工艺参数优化
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作者 徐诗博 王晓强 +2 位作者 田英健 王彪 石青松 《锻压技术》 北大核心 2025年第4期69-76,共8页
为提升轴承套圈的表层性能,以42CrMo高强度钢为研究对象,开展4因素5水平正交试验,基于正交试验数据建立表层性能的指数回归预测模型,并利用方差分析验证了模型的可靠性。通过多目标FAST算法对指数回归预测模型进行优化,得到超声滚挤压... 为提升轴承套圈的表层性能,以42CrMo高强度钢为研究对象,开展4因素5水平正交试验,基于正交试验数据建立表层性能的指数回归预测模型,并利用方差分析验证了模型的可靠性。通过多目标FAST算法对指数回归预测模型进行优化,得到超声滚挤压的最优工艺参数范围及其表层性能的最优取值范围,并进行了试验验证。结果表明:当迭代次数达到900时,表层性能随迭代次数的增加无明显改善,优化后42CrMo高强度钢表层性能的试验值与预测值的误差均控制在10%以内,转速最优为140~210 r·min^(-1)、进给速度为12~20 mm·min^(-1)、振幅为20~25μm、静压力为450~600 N;表面粗糙度最优为0.43~0.49μm、残余压应力为950~1050 MPa、硬度为700~720 HV。研究内容对实际的工程应用具有一定的指导意义。 展开更多
关键词 超声滚挤压 正交试验 表层性能 指数回归 多目标fast算法
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四足机器人室内导航的多模块优化Fast-SLAM算法研究
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作者 周淑凯 张俊杰 +2 位作者 田恬 薛闻雨 汤玉东 《现代信息科技》 2025年第18期169-173,共5页
针对四足机器人在室内环境中存在的定位精度不足、建图效率较低及系统鲁棒性不强等问题,文章提出了一种多模块优化的Fast-SLAM算法框架。在前端里程计阶段,基于范围流模型构建激光点云帧间运动约束,融合自适应迭代加权最小二乘法以提升... 针对四足机器人在室内环境中存在的定位精度不足、建图效率较低及系统鲁棒性不强等问题,文章提出了一种多模块优化的Fast-SLAM算法框架。在前端里程计阶段,基于范围流模型构建激光点云帧间运动约束,融合自适应迭代加权最小二乘法以提升位姿估计的精度与计算效率;在状态估计阶段,引入模糊自适应扩展卡尔曼滤波器,通过动态调整测量噪声协方差增强系统的鲁棒性;在粒子滤波阶段,采用结合极大似然估计与梯度搜索的位姿优化方法,有效降低了重采样误差并提升建图效率。在真实四足机器人平台上对该算法进行部署与验证,实验结果表明,其在平均轨迹误差、计算时间等方面相较于传统方法具有显著提升,展现出良好的环境适应性与工程应用潜力。 展开更多
关键词 室内导航 fast-SLAM 范围流算法 扩展卡尔曼滤波 粒子滤波
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A semi-implicit partition algorithm for fluid-structure coupling problems based on modal force prediction-correction
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作者 Kangdi LI Zili XU +2 位作者 Shizhi ZHAO Lu CHENG Yu FANG 《Chinese Journal of Aeronautics》 2025年第5期275-286,共12页
The implicit partition algorithm used to solve fluid–structure coupling problems has high accuracy,but it requires a long computation time.In this paper,a semi-implicit fluid–structure coupling algorithm based on mo... The implicit partition algorithm used to solve fluid–structure coupling problems has high accuracy,but it requires a long computation time.In this paper,a semi-implicit fluid–structure coupling algorithm based on modal force prediction-correction is proposed to improve the computational efficiency.In the pre-processing stage,the fluid domain is assumed to be a pseudo-elastic solid and merged with the solid domain to form a holistic system,and the normalized modal information of the holistic system is calculated and stored.During the sub-step cycle,the modal superposition method is used to obtain the response of the holistic system with the predicted modal force as the load,so that the deformation of the structure and the updating of the fluid mesh can be achieved simultaneously.After solving the Reynolds-averaged Navier-Stokes equations in the fluid domain,the predicted modal force is corrected and a new sub-step cycle is started until the converged result is obtained.In this method,the computation of the fluid equations and the updating of the dynamic mesh are done implicitly,while the deformation of the structure is done explicitly.Two numerical cases,vortex induced oscillation of an elastic beam and fluid–structure interaction of a final stage blade,are used to verify the efficiency and accuracy of the proposed algorithm.The results show that the proposed method achieves the same accuracy as the implicit method while the computational time is reduced.In the case of the vortex-induced oscillation problem,the computational time can be reduced to 18.6%.In the case of the final stage blade vibration,the computational time can be reduced to 53.8%. 展开更多
关键词 Fluid-structure interaction fast mesh deformation Semi-implicit partition algorithm Prediction-correction method FLUTTER
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基于轻量级Fast-Unet网络的绝缘子图像分割方法
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作者 袁新平 王忠军 路辉 《兵工自动化》 北大核心 2025年第6期23-27,共5页
为快速查找图像中绝缘子缺陷,降低电力事故的发生几率,基于轻量级Fast-Unet网络设计一种绝缘子图像分割算法。对绝缘子航拍图像进行预处理,使其实现重构归一化,通过转换图像元素,计算元素共生概率,从而获取图像的颜色、纹理、形状特征;... 为快速查找图像中绝缘子缺陷,降低电力事故的发生几率,基于轻量级Fast-Unet网络设计一种绝缘子图像分割算法。对绝缘子航拍图像进行预处理,使其实现重构归一化,通过转换图像元素,计算元素共生概率,从而获取图像的颜色、纹理、形状特征;细化通道空间信息特征值,组成一个初始的网络结构,生成分割结果树状图;通过计算图像的模块度和相对模块度,建立轻量级Fast-Unet网络分割模型。实验结果表明:该分割算法在无噪声图像中的综合质量平均值为0.72,在简单背景和复杂背景图像中的综合质量平均值分别为0.57和0.46,可见降噪处理对图像分割的质量起到了正向作用。 展开更多
关键词 轻量级fast-Unet网络 绝缘子串 绝缘子图像 图像分割算法 图像预处理
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一种联合FAST算法和双像光束法平差的相机标定方法
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作者 宋胜嘉 朱勇超 +1 位作者 苏杰 陆秋伶 《合肥工业大学学报(自然科学版)》 北大核心 2025年第6期833-838,共6页
非量测相机以价格低、体积小、使用灵活等优势被广泛应用于高精度测量工作中,但相机标定结果对测量精度影响较大,针对现有相机标定方法存在着精度不够或标定效率不高等问题,文章提出一种联合加速分割检测特征(features from accelerated... 非量测相机以价格低、体积小、使用灵活等优势被广泛应用于高精度测量工作中,但相机标定结果对测量精度影响较大,针对现有相机标定方法存在着精度不够或标定效率不高等问题,文章提出一种联合加速分割检测特征(features from accelerated segment test,FAST)算法和双像光束法平差的相机标定方法。首先利用FAST算法对像片标志点自动提取,利用直接线性变换方法解得相机内、外参数初值;然后基于固定基线长度约束的双像光束法平差模型解算相机相关参数,并通过分类阈值方法提高模型收敛效率。结果表明:该方法相较于普通双像光束法平差的精度有所提升,其标定后的中误差达到0.0064 mm,且实现了相机标定流程的半自动化,提高了作业效率,有望应用于实际场景的相机标定作业。 展开更多
关键词 相机标定 双像光束法 平差模型 fast算法
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具有自适应视图动态超时的Fast-HotStuff区块链共识算法
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作者 高兰辉 张言 +2 位作者 史培中 古春生 景征骏 《信息安全研究》 北大核心 2025年第7期619-625,共7页
Fast-HotStuff算法通过聚合签名实现2阶段流水线拜占庭容错共识.然而,当Fast-HotStuff的领导者故障时,视图切换阶段的死锁问题导致通信复杂度为O(n 2).现有研究主要关注死锁问题,并未考虑拜占庭节点和不稳定网络引起的连续视图超时问题... Fast-HotStuff算法通过聚合签名实现2阶段流水线拜占庭容错共识.然而,当Fast-HotStuff的领导者故障时,视图切换阶段的死锁问题导致通信复杂度为O(n 2).现有研究主要关注死锁问题,并未考虑拜占庭节点和不稳定网络引起的连续视图超时问题.针对这个问题,提出了具有自适应视图动态超时的Fast-HotStuff区块链共识算法AVD-HotStuff.首先,视图动态超时策略算法自适应控制下一次视图超时的持续时间,以避免不稳定网络引起的连续视图超时.其次,领导者等待策略算法将视图切换的通信复杂度从O(n 2)降低到O(n),并通过自适应控制领导者等待时间确保视图切换的效率.最后,基于信誉值的领导者选择策略算法选取可靠节点,防止在视图切换时选取拜占庭节点,避免连续视图超时.与Fast-HotStuff算法相比,当存在拜占庭节点时,AVD-HotStuff算法吞吐量平均提高约51.4%,平均时延减少约59.9%. 展开更多
关键词 fast-HotStuff算法 领导者等待策略 视图动态超时策略 基于信誉值的领导者选择策略 拜占庭容错
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Fast algorithm for constructing neighbor-joining phylogenetic trees 被引量:3
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作者 陈宁涛 王能超 施保昌 《Journal of Southeast University(English Edition)》 EI CAS 2006年第2期176-179,共4页
To improve the performance of Saitou and Nei's algorithm (SN) and Studier and Keppler's improved algorithm (SK) for constructing neighbor-joining phylogenetic trees and reduce the time complexity of the computat... To improve the performance of Saitou and Nei's algorithm (SN) and Studier and Keppler's improved algorithm (SK) for constructing neighbor-joining phylogenetic trees and reduce the time complexity of the computation, a fast algorithm is proposed. The proposed algorithm includes three techniques. First, a linear array A[N] is introduced to store the sum of every row of the distance matrix (the same as SK), which can eliminate many repeated computations. Secondly, the value of A [i] is computed only once at the beginning of the algorithm, and is updated by three elements in the iteration. Thirdly, a very compact formula for the sum of all the branch lengths of operational taxonomic units (OTUs) i and j is designed, and the correctness of the formula is proved. The experimental results show that the proposed algorithm is from tens to hundreds times faster than SN and roughly two times faster than SK when N increases, constructing a tree with 2 000 OTUs in 3 min on a current desktop computer. To earn the time with the cost of the space and reduce the computations in the innermost loop are the basic solutions for algorithms with many loops. 展开更多
关键词 phylogenetic tree neighbor-joining method fast algorithm progressive multiple alignment
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Improvement and performance of parallel multilevel fast multipole algorithm 被引量:16
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作者 Zhanhe Liu Peilin Huang +1 位作者 Zhe Wu Xu Gao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第1期164-169,共6页
The method of establishing data structures plays an important role in the efficiency of parallel multilevel fast multipole algorithm(PMLFMA).Considering the main complements of multilevel fast multipole algorithm(M... The method of establishing data structures plays an important role in the efficiency of parallel multilevel fast multipole algorithm(PMLFMA).Considering the main complements of multilevel fast multipole algorithm(MLFMA) memory,a new parallelization strategy and a modified data octree construction scheme are proposed to further reduce communication in order to improve parallel efficiency.For far interaction,a new scheme called dynamic memory allocation is developed.To analyze the workload balancing performance of a parallel implementation,the original concept of workload balancing factor is introduced and verified by numerical examples.Numerical results show that the above measures improve the parallel efficiency and are suitable for the analysis of electrical large-scale scattering objects. 展开更多
关键词 multilevel fast multipole algorithm(MLFMA) electromagnetic scattering PARALLELIZATION radar cross section(RCS).
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Fast recursive algorithm for two-dimensional Tsallis entropy thresholding method 被引量:2
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作者 Tang Yinggan Di Qiuyan Guan Xinping 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第3期619-624,共6页
Recently, a two-dimensional (2-D) Tsallis entropy thresholding method has been proposed as a new method for image segmentation. But the computation complexity of 2-D Tsallis entropy is very large and becomes an obst... Recently, a two-dimensional (2-D) Tsallis entropy thresholding method has been proposed as a new method for image segmentation. But the computation complexity of 2-D Tsallis entropy is very large and becomes an obstacle to real time image processing systems. A fast recursive algorithm for 2-D Tsallis entropy thresholding is proposed. The key variables involved in calculating 2-D Tsallis entropy are written in recursive form. Thus, many repeating calculations are avoided and the computation complexity reduces to O(L2) from O(L4). The effectiveness of the proposed algorithm is illustrated by experimental results. 展开更多
关键词 image segmentation THRESHOLDING Tsallis entropy fast recursive algorithm
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Efficient analysis of dielectric radomes using multilevel fast multipole algorithm with CRWG basis 被引量:2
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作者 Que Xiaofeng Nie Zaiping Hu Jun 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第1期81-87,共7页
A full-wave analysis of the electromagnetic problem of a three-dimensional (3-D) antenna radiating through a 3-D dielectric radome is preserued. The problem is formulated using the Poggio-Miller-Chang-Harrington- Wu... A full-wave analysis of the electromagnetic problem of a three-dimensional (3-D) antenna radiating through a 3-D dielectric radome is preserued. The problem is formulated using the Poggio-Miller-Chang-Harrington- Wu(PMCHW) approach for homogeneous dielectric objects and the electric field integral equation for conducting objects. The integral equations are discretized by the method of moment (MoM), in which the conducting and dielectric surface/interfaces are represented by curvilinear triangular patches and the unknown equivalent electric and magnetic currents are expanded using curvilinear RWG basis functions. The resultant matrix equation is then solved by the multilevel fast multipole algorithm (MLFMA) and fast far-field approximation (FAFFA) is used to further accelerate the computation. The radiation patterns of dipole arrays in the presence of radomes are presented. The numerical results demonstrate the accuracy and versatility of this method. 展开更多
关键词 multilevel fast multipole algorithm antenna radome curvilinear RWG basis PMCHW formulation fast far-field approximation.
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An adaptive reanalysis method for genetic algorithm with application to fast truss optimization 被引量:3
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作者 Tao Xu Wenjie Zuo +2 位作者 Tianshuang Xu Guangcai Song Ruichuan Li 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第2期225-234,共10页
Although the genetic algorithm (GA) for structural optimization is very robust, it is very computationally intensive and hence slower than optimality criteria and mathematical programming methods. To speed up the de... Although the genetic algorithm (GA) for structural optimization is very robust, it is very computationally intensive and hence slower than optimality criteria and mathematical programming methods. To speed up the design process, the authors present an adaptive reanalysis method for GA and its applications in the optimal design of trusses. This reanalysis technique is primarily derived from the Kirsch's combined approximations method. An iteration scheme is adopted to adaptively determine the number of basis vectors at every generation. In order to illustrate this method, three classical examples of optimal truss design are used to validate the proposed reanalysis-based design procedure. The presented numerical results demonstrate that the adaptive reanalysis technique affects very slightly the accuracy of the optimal solutions and does accelerate the design process, especially for large-scale structures. 展开更多
关键词 Truss structure Adaptive reanalysis ·Genetic algorithm ·fast optimization
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General and efficient parallel approach of finite element-boundary integral-multilevel fast multipole algorithm 被引量:3
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作者 Pan Xiaomin Sheng Xinqing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第2期207-212,共6页
A general and efficient parallel approach is proposed for the first time to parallelize the hybrid finiteelement-boundary-integral-multi-level fast multipole algorithm (FE-BI-MLFMA). Among many algorithms of FE-BI-M... A general and efficient parallel approach is proposed for the first time to parallelize the hybrid finiteelement-boundary-integral-multi-level fast multipole algorithm (FE-BI-MLFMA). Among many algorithms of FE-BI-MLFMA, the decomposition algorithm (DA) is chosen as a basis for the parallelization of FE-BI-MLFMA because of its distinct numerical characteristics suitable for parallelization. On the basis of the DA, the parallelization of FE-BI-MLFMA is carried out by employing the parallelized multi-frontal method for the matrix from the finiteelement method and the parallelized MLFMA for the matrix from the boundary integral method respectively. The programming and numerical experiments of the proposed parallel approach are carried out in the high perfor- mance computing platform CEMS-Liuhui. Numerical experiments demonstrate that FE-BI-MLFMA is efficiently parallelized and its computational capacity is greatly improved without losing accuracy, efficiency, and generality. 展开更多
关键词 finite element-boundary integral-multilevel fast multipole algorithm parallelization.
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Fast algorithm for simulation of normal and oblique penetration into limestone targets 被引量:2
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作者 Xuguang CHEN Duo ZHANG +1 位作者 Shujian YAO Fangyun LU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2017年第5期671-688,共18页
A fast algorithm is proposed to predict penetration trajectory in simulation of normal and oblique penetration of a rigid steel projectile into a limestone target. The algorithm is designed based on the idea of isolat... A fast algorithm is proposed to predict penetration trajectory in simulation of normal and oblique penetration of a rigid steel projectile into a limestone target. The algorithm is designed based on the idea of isolation between the projectile and the target. Corresponding factors of influence are considered, including analytical load model, cratering effect, free surface effect, and separation-reattachment phenomenon. Besides, a method of cavity ring is used to study the process of cavity expansion. Further, description of the projectile's three-dimensional gesture is coded for fast calculation, named PENE3D. A presented. As a result, the algorithm is series of cases with selected normal and oblique penetrations are simulated by the algorithm. The predictions agree with the results of tests, showing that the proposed algorithm is fast and effective in simulation of the penetration process and prediction of the penetration trajectory. 展开更多
关键词 fast algorithm isolation between projectile and target analytical loading model ogive-nosed projectile limestone target
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A novel fast classification filtering algorithm for LiDAR point clouds based on small grid density clustering 被引量:5
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作者 Xingsheng Deng Guo Tang Qingyang Wang 《Geodesy and Geodynamics》 CSCD 2022年第1期38-49,共12页
Clustering filtering is usually a practical method for light detection and ranging(LiDAR)point clouds filtering according to their characteristic attributes.However,the amount of point cloud data is extremely large in... Clustering filtering is usually a practical method for light detection and ranging(LiDAR)point clouds filtering according to their characteristic attributes.However,the amount of point cloud data is extremely large in practice,making it impossible to cluster point clouds data directly,and the filtering error is also too large.Moreover,many existing filtering algorithms have poor classification results in discontinuous terrain.This article proposes a new fast classification filtering algorithm based on density clustering,which can solve the problem of point clouds classification in discontinuous terrain.Based on the spatial density of LiDAR point clouds,also the features of the ground object point clouds and the terrain point clouds,the point clouds are clustered firstly by their elevations,and then the plane point clouds are selected.Thus the number of samples and feature dimensions of data are reduced.Using the DBSCAN clustering filtering method,the original point clouds are finally divided into noise point clouds,ground object point clouds,and terrain point clouds.The experiment uses 15 sets of data samples provided by the International Society for Photogrammetry and Remote Sensing(ISPRS),and the results of the proposed algorithm are compared with the other eight classical filtering algorithms.Quantitative and qualitative analysis shows that the proposed algorithm has good applicability in urban areas and rural areas,and is significantly better than other classic filtering algorithms in discontinuous terrain,with a total error of about 10%.The results show that the proposed method is feasible and can be used in different terrains. 展开更多
关键词 Small grid density clustering DBSCAN fast classification filtering algorithm
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