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New regularization method and iteratively reweighted algorithm for sparse vector recovery 被引量:2
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作者 Wei ZHU Hui ZHANG Lizhi CHENG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2020年第1期157-172,共16页
Motivated by the study of regularization for sparse problems,we propose a new regularization method for sparse vector recovery.We derive sufficient conditions on the well-posedness of the new regularization,and design... Motivated by the study of regularization for sparse problems,we propose a new regularization method for sparse vector recovery.We derive sufficient conditions on the well-posedness of the new regularization,and design an iterative algorithm,namely the iteratively reweighted algorithm(IR-algorithm),for efficiently computing the sparse solutions to the proposed regularization model.The convergence of the IR-algorithm and the setting of the regularization parameters are analyzed at length.Finally,we present numerical examples to illustrate the features of the new regularization and algorithm. 展开更多
关键词 regularization method iteratively reweighted algorithm(IR-algorithm) sparse vector recovery
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A PARALLEL COMPUTATION SCHEME FOR IMPLICIT RUNGE-KUTTA METHODS AND THE ITERATIVELY B-CONVERGENCE OF ITS NEWTON ITERATIVE PROCESS
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作者 赵双锁 王昌银 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 1994年第1期54-66,共13页
In this paper, based on the implicit Runge-Kutta(IRK) methods, we derive a class of parallel scheme that can be implemented on the parallel computers with Ns(N is a positive even number) processors efficiently, and di... In this paper, based on the implicit Runge-Kutta(IRK) methods, we derive a class of parallel scheme that can be implemented on the parallel computers with Ns(N is a positive even number) processors efficiently, and discuss the iteratively B-convergence of the Newton iterative process for solving the algebraic equations of the scheme, secondly we present a strategy providing initial values parallelly for the iterative process. Finally, some numerical results show that our parallel scheme is higher efficient as N is not so large. 展开更多
关键词 IMPLICIT Range-Kutta methods NEWTON ITERATIVE process parallel COMPUTATION iteratively B-CONVERGENCE
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Continuous Iteratively Reweighted Least Squares Algorithm for Solving Linear Models by Convex Relaxation
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作者 Xian Luo Wanzhou Ye 《Advances in Pure Mathematics》 2019年第6期523-533,共11页
In this paper, we present continuous iteratively reweighted least squares algorithm (CIRLS) for solving the linear models problem by convex relaxation, and prove the convergence of this algorithm. Under some condition... In this paper, we present continuous iteratively reweighted least squares algorithm (CIRLS) for solving the linear models problem by convex relaxation, and prove the convergence of this algorithm. Under some conditions, we give an error bound for the algorithm. In addition, the numerical result shows the efficiency of the algorithm. 展开更多
关键词 Linear Models CONTINUOUS iteratively Reweighted Least SQUARES CONVEX RELAXATION Principal COMPONENT Analysis
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The Behavior of Normality when Iteratively Finding the Normal to a Line in an <sub>lp</sub>Geometry
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作者 Joshua M. Fitzhugh David L. Farnsworth 《Advances in Pure Mathematics》 2013年第8期647-652,共6页
The normal direction to the normal direction to a line in Minkowski geometries generally does not give the original line. We show that in lp geometries with p>1?repeatedly finding the normal line through the origin... The normal direction to the normal direction to a line in Minkowski geometries generally does not give the original line. We show that in lp geometries with p>1?repeatedly finding the normal line through the origin gives sequences of lines that monotonically approach specific lines of symmetry of the unit circle. Which lines of symmetry that are approached depends upon the value of p and the slope of the initial line. 展开更多
关键词 MINKOWSKI GEOMETRY Geometric Construction Iteration NORMALITY LP GEOMETRY Radon Curve
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Feedback Feedforward Iterative Learning Control for Networked Nonlinear System under Iteratively Variable Trial Lengths and Data Dropouts
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作者 Yunshan Wei Sixian Xiong Wenli Shang 《Tsinghua Science and Technology》 2025年第5期1897-1910,共14页
This paper proposed a feedback feedforward Iterative Learning Control(ILC)law for nonlinear system with iteratively variable trial lengths under a networked systems structure,where the both sensor and actuator occurs ... This paper proposed a feedback feedforward Iterative Learning Control(ILC)law for nonlinear system with iteratively variable trial lengths under a networked systems structure,where the both sensor and actuator occurs random data lost separately.The feedforward ILC part includes the calculated input signal,actual input signal,and the modified tracking error of last iteration.Some tracking signal would be lost at last iteration because of the iterative varying trial lengths.In order to offset the missing signal of last trial,the tracking error of present trial is adopted by feedback control part.It is established that the convergence relied on the feedforward control gain merely,while the rate of convergence is also expedited by the feedback control component.When the initial state expectation equals to the reference one,it is established that the tracking error expectation can be controlled to zero.With an illustrative simulation,the effectiveness of the developed algorithm can be demonstrated. 展开更多
关键词 iterative learning control variable trial lengths data dropouts feedback control nonlinear discrete-time system
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A New Inversion-free Iterative Method for Solving the Nonlinear Matrix Equation and Its Application in Optimal Control
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作者 GAO Xiangyu XIE Weiwei ZHANG Lina 《应用数学》 北大核心 2026年第1期143-150,共8页
In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to ... In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method. 展开更多
关键词 Nonlinear matrix equation Maximal positive definite solution Inversion-free iterative method Optimal control
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基于栅元嵌套网格的停堆剂量率方法初步验证及应用
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作者 郑征 夏春梅 +4 位作者 梅其良 解均涵 史涛 高静 王梦琪 《强激光与粒子束》 北大核心 2025年第9期118-124,共7页
停堆剂量率计算分析是核反应堆辐射安全的重要内容。为了分析车载微型移动核电源的停堆剂量率,研究了基于栅元嵌套网格的停堆剂量率计算方法。该方法在严格两步法的计算框架下,对活化光子源的抽样方法进行了改进。通过构建几何简单的包... 停堆剂量率计算分析是核反应堆辐射安全的重要内容。为了分析车载微型移动核电源的停堆剂量率,研究了基于栅元嵌套网格的停堆剂量率计算方法。该方法在严格两步法的计算框架下,对活化光子源的抽样方法进行了改进。通过构建几何简单的包围盒,抽样得到源栅元内的粒子分布,从而提高了抽样效率和精度。在国际热核聚变实验堆(ITER)停堆剂量率基准题中进行了验证,该方法与参考解符合较好。基于该方法开展了兆瓦级车载微型移动核电源Megapower的停堆剂量率分析,计算结果表明热管贯穿端剂量率水平相对较高。该方法可用于反应堆停堆剂量率的计算分析,能够准确评估结构材料活化源及其产生的剂量率,对于反应堆屏蔽设计、维修计划的制定及退役具有重要的参考意义。 展开更多
关键词 停堆剂量率 严格两步法 源粒子抽样 ITER基准题 Megapower
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ITER PF6大型超导磁体线圈吊装精密准直测量关键技术 被引量:1
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作者 顾永奇 郑元阳 +4 位作者 袁忠 王琳 邓磊 李志虎 ITER TAC1项目联合体团队 《核聚变与等离子体物理》 北大核心 2025年第1期19-26,共8页
PF6超导磁体线圈是ITER装置上首个吊装且重量最重的磁体线圈,其吊装精度直接影响后续部件的安装。根据ITER总装厂房和装置大厅的结构状况、基准分布和通视条件等,通过对线圈吊具负载变形测试、吊装测试、线圈方位调整、吊装路径、最终... PF6超导磁体线圈是ITER装置上首个吊装且重量最重的磁体线圈,其吊装精度直接影响后续部件的安装。根据ITER总装厂房和装置大厅的结构状况、基准分布和通视条件等,通过对线圈吊具负载变形测试、吊装测试、线圈方位调整、吊装路径、最终定位等阶段的准直测量过程进行的模拟测量分析,简化了测量方案,优化了准直测量关键步骤,保证了ITER TAC1项目进度。实现了PF6线圈一次性吊装落位精度±4mm的要求,经评估测量不确定度为0.66mm,满足ITER公差与测量不确定度比值不小于5的准则要求。 展开更多
关键词 ITER PF6线圈 精密吊装 准直测量 测量模拟分析
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Local Rate of Convergence in the Functional Limit Theorem for Increments of a Fractional Brownian Motion 被引量:1
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作者 LIU Yonghong DING Ding ZHOU Xia 《数学进展》 北大核心 2025年第1期197-211,共15页
In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):104... In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):1045-1049]and Monrad and Rootzén[Probab.Theory Related Fields,1995,101(2):173-192]. 展开更多
关键词 fractional Brownian motion INCREMENT local functional law of the iterated logarithm large deviation small deviation
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Active polarization high-resolution imaging through complex scattering media 被引量:2
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作者 Meng Xiang Xue Dong +6 位作者 Tianyu Wang Sen Wang Jingjing Ge Jinpeng Liu Qianqian Liu Fei Liu Xiaopeng Shao 《Advanced Photonics Nexus》 2025年第1期127-137,共11页
High-resolution seeing through complex scattering media such as turbid water,biological tissues,and mist is a significant challenge because the strong scattering scrambles the light paths and forms the scattering wall... High-resolution seeing through complex scattering media such as turbid water,biological tissues,and mist is a significant challenge because the strong scattering scrambles the light paths and forms the scattering wall.We propose an active polarized iterative optimization approach for high-resolution imaging through complex scattering media.By acquiring a series of sub-polarized images,we can capture the diverse pattern-illuminated images with various high-frequency component information caused by the Brownian motion of complex scattering materials,which are processed using the common-mode rejection of polarization characteristics to extract target information from scattering medium information.Following that,our computational reconstruction technique employs an iterative optimization algorithm that commences with patternilluminated Fourier ptychography for reconstructing the high-resolution scene.It is extremely important that our approach for high-resolution imaging through complex scattering media is not limited by priori information and optical memory effect.The proposed approach is suitable for not only dynamic but also static scattering media,which may find applications in the biomedicine field,such as skin abnormalities,non-invasive blood flow,and superficial tumors. 展开更多
关键词 complex scattering media iterative optimization POLARIZATION Fourier ptychography.
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Fault-observer-based iterative learning model predictive controller for trajectory tracking of hypersonic vehicles 被引量:2
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作者 CUI Peng GAO Changsheng AN Ruoming 《Journal of Systems Engineering and Electronics》 2025年第3期803-813,共11页
This work proposes the application of an iterative learning model predictive control(ILMPC)approach based on an adaptive fault observer(FOBILMPC)for fault-tolerant control and trajectory tracking in air-breathing hype... This work proposes the application of an iterative learning model predictive control(ILMPC)approach based on an adaptive fault observer(FOBILMPC)for fault-tolerant control and trajectory tracking in air-breathing hypersonic vehicles.In order to increase the control amount,this online control legislation makes use of model predictive control(MPC)that is based on the concept of iterative learning control(ILC).By using offline data to decrease the linearized model’s faults,the strategy may effectively increase the robustness of the control system and guarantee that disturbances can be suppressed.An adaptive fault observer is created based on the suggested ILMPC approach in order to enhance overall fault tolerance by estimating and compensating for actuator disturbance and fault degree.During the derivation process,a linearized model of longitudinal dynamics is established.The suggested ILMPC approach is likely to be used in the design of hypersonic vehicle control systems since numerical simulations have demonstrated that it can decrease tracking error and speed up convergence when compared to the offline controller. 展开更多
关键词 hypersonic vehicle actuator fault tracking control iterative learning control(ILC) model predictive control(MPC) fault observer
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Optimal Production Capacity Matching for Blockchain-Enabled Manufacturing Collaboration With the Iterative Double Auction Method 被引量:1
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作者 Ying Chen Feilong Lin +2 位作者 Zhongyu Chen Changbing Tang Cailian Chen 《IEEE/CAA Journal of Automatica Sinica》 2025年第3期550-562,共13页
The increased demand for personalized customization calls for new production modes to enhance collaborations among a wide range of manufacturing practitioners who unnecessarily trust each other.In this article,a block... The increased demand for personalized customization calls for new production modes to enhance collaborations among a wide range of manufacturing practitioners who unnecessarily trust each other.In this article,a blockchain-enabled manufacturing collaboration framework is proposed,with a focus on the production capacity matching problem for blockchainbased peer-to-peer(P2P)collaboration.First,a digital model of production capacity description is built for trustworthy and transparent sharing over the blockchain.Second,an optimization problem is formulated for P2P production capacity matching with objectives to maximize both social welfare and individual benefits of all participants.Third,a feasible solution based on an iterative double auction mechanism is designed to determine the optimal price and quantity for production capacity matching with a lack of personal information.It facilitates automation of the matching process while protecting users'privacy via blockchainbased smart contracts.Finally,simulation results from the Hyperledger Fabric-based prototype show that the proposed approach increases social welfare by 1.4%compared to the Bayesian game-based approach,makes all participants profitable,and achieves 90%fairness of enterprises. 展开更多
关键词 Blockchain iterative double auction manufacturing collaboration production capacity matching
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Improved algorithm of multi-mainlobe interference suppression under uncorrelated and coherent conditions 被引量:1
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作者 CAI Miaohong CHENG Qiang +1 位作者 MENG Jinli ZHAO Dehua 《Journal of Southeast University(English Edition)》 2025年第1期84-90,共7页
A new method based on the iterative adaptive algorithm(IAA)and blocking matrix preprocessing(BMP)is proposed to study the suppression of multi-mainlobe interference.The algorithm is applied to precisely estimate the s... A new method based on the iterative adaptive algorithm(IAA)and blocking matrix preprocessing(BMP)is proposed to study the suppression of multi-mainlobe interference.The algorithm is applied to precisely estimate the spatial spectrum and the directions of arrival(DOA)of interferences to overcome the drawbacks associated with conventional adaptive beamforming(ABF)methods.The mainlobe interferences are identified by calculating the correlation coefficients between direction steering vectors(SVs)and rejected by the BMP pretreatment.Then,IAA is subsequently employed to reconstruct a sidelobe interference-plus-noise covariance matrix for the preferable ABF and residual interference suppression.Simulation results demonstrate the excellence of the proposed method over normal methods based on BMP and eigen-projection matrix perprocessing(EMP)under both uncorrelated and coherent circumstances. 展开更多
关键词 mainlobe interference suppression adaptive beamforming spatial spectral estimation iterative adaptive algorithm blocking matrix preprocessing
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An Iterated Greedy Algorithm with Memory and Learning Mechanisms for the Distributed Permutation Flow Shop Scheduling Problem
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作者 Binhui Wang Hongfeng Wang 《Computers, Materials & Continua》 SCIE EI 2025年第1期371-388,共18页
The distributed permutation flow shop scheduling problem(DPFSP)has received increasing attention in recent years.The iterated greedy algorithm(IGA)serves as a powerful optimizer for addressing such a problem because o... The distributed permutation flow shop scheduling problem(DPFSP)has received increasing attention in recent years.The iterated greedy algorithm(IGA)serves as a powerful optimizer for addressing such a problem because of its straightforward,single-solution evolution framework.However,a potential draw-back of IGA is the lack of utilization of historical information,which could lead to an imbalance between exploration and exploitation,especially in large-scale DPFSPs.As a consequence,this paper develops an IGA with memory and learning mechanisms(MLIGA)to efficiently solve the DPFSP targeted at the mini-malmakespan.InMLIGA,we incorporate a memory mechanism to make a more informed selection of the initial solution at each stage of the search,by extending,reconstructing,and reinforcing the information from previous solutions.In addition,we design a twolayer cooperative reinforcement learning approach to intelligently determine the key parameters of IGA and the operations of the memory mechanism.Meanwhile,to ensure that the experience generated by each perturbation operator is fully learned and to reduce the prior parameters of MLIGA,a probability curve-based acceptance criterion is proposed by combining a cube root function with custom rules.At last,a discrete adaptive learning rate is employed to enhance the stability of the memory and learningmechanisms.Complete ablation experiments are utilized to verify the effectiveness of the memory mechanism,and the results show that this mechanism is capable of improving the performance of IGA to a large extent.Furthermore,through comparative experiments involving MLIGA and five state-of-the-art algorithms on 720 benchmarks,we have discovered that MLI-GA demonstrates significant potential for solving large-scale DPFSPs.This indicates that MLIGA is well-suited for real-world distributed flow shop scheduling. 展开更多
关键词 Distributed permutation flow shop scheduling MAKESPAN iterated greedy algorithm memory mechanism cooperative reinforcement learning
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Multiplicity and Stability of Closed Characteristics on Compact Convex Hypersurfaces in R^(2n)
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作者 WANG Wei 《数学进展》 北大核心 2025年第4期673-686,共14页
A survey of recent progress on the multiplicity and stability problems for closed characteristics on compact convex hypersurfaces in R^(2n) is given.
关键词 compact convex hypersurface closed characteristic Hamiltonian system Morse theory index iteration theory
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Geophysical data sparse reconstruction based on L0-norm minimization 被引量:6
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作者 陈国新 陈生昌 +1 位作者 王汉闯 张博 《Applied Geophysics》 SCIE CSCD 2013年第2期181-190,236,共11页
Missing data are a problem in geophysical surveys, and interpolation and reconstruction of missing data is part of the data processing and interpretation. Based on the sparseness of the geophysical data or the transfo... Missing data are a problem in geophysical surveys, and interpolation and reconstruction of missing data is part of the data processing and interpretation. Based on the sparseness of the geophysical data or the transform domain, we can improve the accuracy and stability of the reconstruction by transforming it to a sparse optimization problem. In this paper, we propose a mathematical model for the sparse reconstruction of data based on the LO-norm minimization. Furthermore, we discuss two types of the approximation algorithm for the LO- norm minimization according to the size and characteristics of the geophysical data: namely, the iteratively reweighted least-squares algorithm and the fast iterative hard thresholding algorithm. Theoretical and numerical analysis showed that applying the iteratively reweighted least-squares algorithm to the reconstruction of potential field data exploits its fast convergence rate, short calculation time, and high precision, whereas the fast iterative hard thresholding algorithm is more suitable for processing seismic data, moreover, its computational efficiency is better than that of the traditional iterative hard thresholding algorithm. 展开更多
关键词 Geophysical data sparse reconstruction LO-norm minimization iterativelyreweighted least squares fast iterative hard thresholding
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Improvement of Lattice Parameter Accuracy in Single Crystal XRD Based on a Laser-Induced X-Ray Source
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作者 LIU Jin WANG Qiannan LI Jiangtao 《高压物理学报》 北大核心 2025年第4期9-15,共7页
The lattice parameter,measured with sufficient accuracy,can be utilized to evaluate the quality of single crystals and to determine the equation of state for materials.We propose an iterative method for obtaining more... The lattice parameter,measured with sufficient accuracy,can be utilized to evaluate the quality of single crystals and to determine the equation of state for materials.We propose an iterative method for obtaining more precise lattice parameters using the interaction points for the pseudo-Kossel pattern obtained from laser-induced X-ray diffraction(XRD).This method has been validated by the analysis of an XRD experiment conducted on iron single crystals.Furthermore,the method was used to calculate the compression ratio and rotated angle of an LiF sample under high pressure loading.This technique provides a robust tool for in-situ characterization of structural changes in single crystals under extreme conditions.It has significant implications for studying the equation of state and phase transitions. 展开更多
关键词 lattice parameter measurement accuracy single crystal X-ray diffraction iterative algorithm high pressure ratio of compression
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地球最大核聚变装置的电磁系统完工
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《科技导报》 北大核心 2025年第10期7-8,共2页
2025年4月30日,国际热核聚变实验堆(ITER)组织在其官方网站正式宣布,历经数十年的攻关,这座汇集全球30余国科研力量打造的“人造太阳”取得关键突破:全球规模最大、性能最强的脉冲超导电磁体系统建造完成。ITER装置本质上是一个托卡马... 2025年4月30日,国际热核聚变实验堆(ITER)组织在其官方网站正式宣布,历经数十年的攻关,这座汇集全球30余国科研力量打造的“人造太阳”取得关键突破:全球规模最大、性能最强的脉冲超导电磁体系统建造完成。ITER装置本质上是一个托卡马克型聚变反应装置,目标是在地球上模拟太阳内部的核聚变反应,即将氢的同位素(氘和氚)聚合生成氦原子核,从而释放巨大能量。 展开更多
关键词 托卡马克 ITER 脉冲超导电磁体系统
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A New Technique for Constructing Higher-order Iterative Methods to Solve Nonlinear Systems
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作者 XIAO Xiaoyong 《应用数学》 北大核心 2025年第3期762-774,共13页
In this paper,a new technique is introduced to construct higher-order iterative methods for solving nonlinear systems.The order of convergence of some iterative methods can be improved by three at the cost of introduc... In this paper,a new technique is introduced to construct higher-order iterative methods for solving nonlinear systems.The order of convergence of some iterative methods can be improved by three at the cost of introducing only one additional evaluation of the function in each step.Furthermore,some new efficient methods with a higher-order of convergence are obtained by using only a single matrix inversion in each iteration.Analyses of convergence properties and computational efficiency of these new methods are made and testified by several numerical problems.By comparison,the new schemes are more efficient than the corresponding existing ones,particularly for large problem sizes. 展开更多
关键词 Systems of nonlinear equation Order of convergence Higher-order method Extended Newton iteration Computational efficiency
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基于测量数据的虚拟装配技术在ITER校正场线圈装配中的应用
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作者 袁忠 顾永奇 +3 位作者 郑元阳 王琳 邓磊 马国江 《核聚变与等离子体物理》 北大核心 2025年第2期212-219,共8页
ITER底部校正场线圈(BCC)的预装配是继PF6/PF5线圈预装配后,ITER总装现场又一个大型磁体线圈装配的关键里程碑。由于BCC将预装在PF6和馈线环之间,装配间隙狭小,以及其自身形状的不规则性和装配精度要求高等因素,导致BCC的吊装定位成为... ITER底部校正场线圈(BCC)的预装配是继PF6/PF5线圈预装配后,ITER总装现场又一个大型磁体线圈装配的关键里程碑。由于BCC将预装在PF6和馈线环之间,装配间隙狭小,以及其自身形状的不规则性和装配精度要求高等因素,导致BCC的吊装定位成为施工难点。因而发展了基于准直测量数据的虚拟装配技术。根据ITER预装大厅内已安装部件的空间位置测量数据、基准分布和通视条件,利用BCC交付时的轮廓测量数据,对线圈及支撑进行虚拟分析和位置调整,优化吊装路径,模拟分析吊装测量过程,并合理规划装配间隙,以保证线圈的吊装安全和准确定位。6个BCC的成功预装,验证了基于测量数据的虚拟装配技术的可行性。 展开更多
关键词 ITER底部校正场线圈 虚拟装配 准直测量 测量模拟分析
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