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HIGH ORDER PROBABILISTIC NUMERICAL METHODS FOR FORWARD BACKWARD STOCHASTIC DIFFERENTIAL EQUATIONS 认领 引用
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作者 Qiang Han Yurong Liu 《Journal of Computational Mathematics》 SCIE CSCD 2026年第6期1631-1661,共31页
In this paper,we design novel high order probabilistic numerical algorithms for forward backward stochastic differential equations.Moreover,we derive the error estimates and prove the high order convergence rates of t... In this paper,we design novel high order probabilistic numerical algorithms for forward backward stochastic differential equations.Moreover,we derive the error estimates and prove the high order convergence rates of the proposed schemes.Because the proposed scheme involves conditional expectations,an estimator based on the multilevel Monte Carlo method is applied to approximate the conditional expectations.Furthermore,we theoretically demonstrate that the computational complexity of our numerical method is proportional to the square of prescribed accuracy.Numerical experiments are given to illustrate the theoretical results. 展开更多
关键词 Forward Backward Stochastic Differential Equation Probabilistic Numerical Method Multilevel Monte Carlo Computational Complexity High Order Discretization
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Forward and backward models for fault diagnosis based on parallel genetic algorithms 认领 引用 被引量：10
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作者 Yi LIU Ying LI +1 位作者 Yi-jia CAO Chuang-xin GUO 《Journal of Zhejiang University-SCIENCE A》 SCIE EI CAS 2008年第10期1420-1425,共6页
In this paper, a mathematical model consisting of forward and backward models is built on parallel genetic algorithms (PGAs) for fault diagnosis in a transmission power system. A new method to reduce the scale of faul... In this paper, a mathematical model consisting of forward and backward models is built on parallel genetic algorithms (PGAs) for fault diagnosis in a transmission power system. A new method to reduce the scale of fault sections is developed in the forward model and the message passing interface (MPI) approach is chosen to parallel the genetic algorithms by global sin-gle-population master-slave method (GPGAs). The proposed approach is applied to a sample system consisting of 28 sections, 84 protective relays and 40 circuit breakers. Simulation results show that the new model based on GPGAs can achieve very fast computation in online applications of large-scale power systems. 展开更多
关键词 Forward and backward models Fault diagnosis Global single-population master-slave genetic algorithms （GPGAs） Parallel computation
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The parallel 3D magnetotelluric forward modeling algorithm 认领 引用 被引量：34
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作者 Tan Handong Tong Tuo Lin Changhong 《Applied Geophysics》 2006年第4期197-202,共6页
The workload of the 3D magnetotelluric forward modeling algorithm is so large that the traditional serial algorithm costs an extremely large compute time. However, the 3D forward modeling algorithm can process the dat... The workload of the 3D magnetotelluric forward modeling algorithm is so large that the traditional serial algorithm costs an extremely large compute time. However, the 3D forward modeling algorithm can process the data in the frequency domain, which is very suitable for parallel computation. With the advantage of MPI and based on an analysis of the flow of the 3D magnetotelluric serial forward algorithm, we suggest the idea of parallel computation and apply it. Three theoretical models are tested and the execution efficiency is compared in different situations. The results indicate that the parallel 3D forward modeling computation is correct and the efficiency is greatly improved. This method is suitable for large size geophysical computations. 展开更多
关键词 Magnetotelluric 3D forward modeling MPI parallel programming design 3D staggered-grid finite difference method parallel algorithm.
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A modified forward and backward reaching inverse kinematics based incremental control for space manipulators 认领 引用 被引量：4
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作者 Gangqi DONG Panfeng HUANG +1 位作者 Yongjie WANG Rongsheng LI 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2022年第12期287-295,共9页
Forward and backward reaching inverse kinematics(FABRIK)is an efficient two-stage iterative solver for inverse kinematics of spherical-joint manipulator without the calculation of Jacobian matrix.Based on FABRIK,this ... Forward and backward reaching inverse kinematics(FABRIK)is an efficient two-stage iterative solver for inverse kinematics of spherical-joint manipulator without the calculation of Jacobian matrix.Based on FABRIK,this paper presents an incremental control scheme for a free-floating space manipulator consists of revolute joints and rigid links with the consideration of joint constraints and dynamic coupling effect.Due to the characteristics of FABRIK,it can induce large angular movements on specific joints.Apart from that,FABRIK maps three dimensional(3D)problem into two dimensional(2D)problem by a simple geometric projection.This operation can cause infinite loops in some cases.In order to overcome these issues and apply FABRIK on space manipulators,an increments allocation method is developed to constrain the angular movements as well as to re-orient the end-effector.The manipulator is re-positioned based on the momentum conservation law.Instead of pure target position tracking,the orientation control of the end-effector is also considered.Numerical simulation is performed to testify and demonstrate the effectiveness and reliability of the proposed incremental control approach. 展开更多
关键词 Forward and backward reaching inverse kinematics(FABRIK) Incremental control Inverse kinematics Manipulator control Robotic capture
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A Kind of Second-Order Learning Algorithm Based on Generalized Cost Criteria in Multi-Layer Feed-Forward Neural Networks 认领 引用
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作者 张长江 付梦印 金梅 《Journal of Beijing Institute of Technology》 EI CAS 2003年第2期119-124,共6页
A kind of second order algorithm--recursive approximate Newton algorithm was given by Karayiannis. The algorithm was simplified when it was formulated. Especially, the simplification to matrix Hessian was very relucta... A kind of second order algorithm--recursive approximate Newton algorithm was given by Karayiannis. The algorithm was simplified when it was formulated. Especially, the simplification to matrix Hessian was very reluctant, which led to the loss of valuable information and affected performance of the algorithm to certain extent. For multi layer feed forward neural networks, the second order back propagation recursive algorithm based generalized cost criteria was proposed. It is proved that it is equivalent to Newton recursive algorithm and has a second order convergent rate. The performance and application prospect are analyzed. Lots of simulation experiments indicate that the calculation of the new algorithm is almost equivalent to the recursive least square multiple algorithm. The algorithm and selection of networks parameters are significant and the performance is more excellent than BP algorithm and the second order learning algorithm that was given by Karayiannis. 展开更多
关键词 multi layer feed forward neural networks BP algorithm Newton recursive algorithm
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THE REGULARIZED SOLUTION APPROXIMATION OF FORWARD/BACKWARD PROBLEMS FOR A FRACTIONAL PSEUDO-PARABOLIC EQUATION WITH RANDOM NOISE 认领 引用
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作者 狄华斐 容伟杰 《Acta Mathematica Scientia》 SCIE CSCD 2023年第1期324-348,共25页
This paper deals with the forward and backward problems for the nonlinear fractional pseudo-parabolic equation ut+(-Δ)s1ut+β(-Δ)s2u=F(u,x,t)subject o random Gaussian white noise for initial and final data.Und... This paper deals with the forward and backward problems for the nonlinear fractional pseudo-parabolic equation ut+(-Δ)s1ut+β(-Δ)s2u=F(u,x,t)subject o random Gaussian white noise for initial and final data.Under the suitable assumptions s1,s2andβ,we first show the ill-posedness of mild solutions for forward and backward problems in the sense of Hadamard,which are mainly driven by random noise.Moreover,we propose the Fourier truncation method for stabilizing the above ill-posed problems.We derive an error estimate between the exact solution and its regularized solution in an E‖·‖Hs22norm,and give some numerical examples illustrating the effect of above method. 展开更多
关键词 regularized solution approximation forward/backward problems fractional Laplacian Gaussian white noise Fourier truncation method
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带驻留时间HMM2的Forward-Backward算法 认领 引用
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作者 杜世平 汪建 《重庆工商大学学报（自然科学版）》 2007年第1期9-11,共3页
讨论了用状态驻留时间来模型化传统HMM2模型,对传统HMM2的状态转移和输出观测值的Markov假设条件作了改进,在新模型的转移概率和输出观测值的概率中加入驻留时间,并在传统HMM2的基础上定义了新模型的前向-后向变量算法,导出了新模型的前... 讨论了用状态驻留时间来模型化传统HMM2模型,对传统HMM2的状态转移和输出观测值的Markov假设条件作了改进,在新模型的转移概率和输出观测值的概率中加入驻留时间,并在传统HMM2的基础上定义了新模型的前向-后向变量算法,导出了新模型的前向-后向算法的迭代公式,以及在给定模型λ的条件下,产生观测序列O的概率计算公式. 展开更多
关键词 二阶隐马尔可夫模型 前向-后向算法 驻留时间
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A Mixed Real-time Algorithm for the Forward Kinematics of Stewart Parallel Manipulator 认领 引用
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作者 王孙安 万亚民 《Journal of Electronic Science and Technology of China》 2006年第2期173-180,共8页
Aimed at the real-time forward kinematics solving problem of Stewart parallel manipulator in the control course, a mixed algorithm combining immune evolutionary algorithm and numerical iterative scheme is proposed. Fi... Aimed at the real-time forward kinematics solving problem of Stewart parallel manipulator in the control course, a mixed algorithm combining immune evolutionary algorithm and numerical iterative scheme is proposed. Firstly taking advantage of simpleness of inverse kinematics, the forward kinematics is transformed to an optimal problem. Immune evolutionary algorithm is employed to find approximate solution of this optimal problem in manipulator＇s workspace. Then using above solution as iterative initialization, a speedy numerical iterative scheme is proposed to get more precise solution. In the manipulator running course, the iteration initialization can be selected as the last period position and orientation. Because the initialization is closed to correct solution, solving precision is high and speed is rapid enough to satisfy real-time requirement. This mixed forward kinematics algorithm is applied to real Stewart parallel manipulator in the real-time control course. The examination result shows that the algorithm is very efficient and practical. 展开更多
关键词 stewart parallel manipulator forward kinematics immune evolutionary algorithm numerical iterative scheme real-time control
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Forward displacement analysis of a redundant parallel manipulator by approximation algorithms 认领 引用
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作者 赵永杰 邱可 《Journal of Chongqing University》 2010年第1期12-20,共9页
This paper presents the forward displacement analysis of an 8-PSS(prismatic-spherical-spherical)redundant parallel manipulator whose moving platform is linked to the base platform by eight kinemtic chains consisting o... This paper presents the forward displacement analysis of an 8-PSS(prismatic-spherical-spherical)redundant parallel manipulator whose moving platform is linked to the base platform by eight kinemtic chains consisting of a PSS joint and a strut with fixed length.A general approximation algorithm is used to solve the problem.To avoid the extraction of root in the approximation process,the forward displacement analysis of the 8-PSS redundant parallel manipulator is transformed into another equivalent problem on the assumption that the strut is extensible while the slider is fixed.The problem is solved by a modified approximation algorithm which predicates that the manipulator will move along a pose vector to reduce the difference between the desired configuration and an instantaneous one,and the best movement should be with minimum norm and least quadratic sum.The characteristic of this modified algorithm is that its convergence domain is larger than that of the general approximation algorithm.Simulation results show that the modelified algorithm is general and can be used for the forward displacement analysis of the redundant parallel manipulator actuated by a revolute joint. 展开更多
关键词 redundant narallel maninulator： forward displacement analvsis： annroximation algorithm
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Determination of the Backward Predictability Limit and Its Relationship with the Forward Predictability Limit 认领 引用 被引量：2
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作者 Xuan LI Ruiqiang DING Jianping LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2019年第6期669-677,共9页
In this work, two types of predictability are proposed—forward and backward predictability—and then applied in the nonlinear local Lyapunov exponent approach to the Lorenz63 and Lorenz96 models to quantitatively est... In this work, two types of predictability are proposed—forward and backward predictability—and then applied in the nonlinear local Lyapunov exponent approach to the Lorenz63 and Lorenz96 models to quantitatively estimate the local forward and backward predictability limits of states in phase space. The forward predictability mainly focuses on the forward evolution of initial errors superposed on the initial state over time, while the backward predictability is mainly concerned with when the given state can be predicted before this state happens. From the results, there is a negative correlation between the local forward and backward predictability limits. That is, the forward predictability limits are higher when the backward predictability limits are lower, and vice versa. We also find that the sum of forward and backward predictability limits of each state tends to fluctuate around the average value of sums of the forward and backward predictability limits of sufficient states.Furthermore, the average value is constant when the states are sufficient. For different chaotic systems, the average value is dependent on the chaotic systems and more complex chaotic systems get a lower average value. For a single chaotic system,the average value depends on the magnitude of initial perturbations. The average values decrease as the magnitudes of initial perturbations increase. 展开更多
关键词 nonlinear local Lyapunov exponent forward and backward predictability limit negative correlation average value
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Nonhomogeneous(H,Q)-Process:The Backward and Forward Equations 认领 引用
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作者 陈柳鑫 李俊平 《Journal of Southeast University(English Edition)》 CAS 2002年第2期180-183,共4页
As for the backward and forward equation of nonhomogeneous(H, Q) -processes,we proof them in a new way. On the base of that, this paper gives the direct computational formalfor one dimensional distribution of the nonh... As for the backward and forward equation of nonhomogeneous(H, Q) -processes,we proof them in a new way. On the base of that, this paper gives the direct computational formalfor one dimensional distribution of the nonhomogeneous(H, Q) -process. 展开更多
关键词 nonhomogeneous(H Q)-process backward and forward equations one-dimensional distribution
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A Study on Parallel Computation Based on 3D Forward Algorithm of Gravity 认领 引用 被引量：1
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作者 Mao Wang Yuanman Zheng Changli Yao 《International Journal of Geosciences》 CAS 2017年第9期1073-1079,共7页
Interpretation of geophysical material is the prospecting method. Interpretation of Gravity-megnetic data is based on data processing and inversion. When the grid is divided into several million cells, the computing t... Interpretation of geophysical material is the prospecting method. Interpretation of Gravity-megnetic data is based on data processing and inversion. When the grid is divided into several million cells, the computing task is heavy and time-consuming. In order to increase efficiency of the 3D forward modeling, the paper will adopt MPI parallel algorithm and the several processes will deal with data in the method. Finally, we can gather the result. Through comparing the result of sequence algorithm with the result of MPI parallel algorithm, we can see the result is the same. When the number of processes is 2 to 8, the speed-up ratio is 1.97 to 5. The MPI parallel algorithm is very efficient. 展开更多
关键词 Gravity 3D Forward Modeling Parallel Algorithm MPI
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求解双层凸优化问题的Forward-Backward分裂算法 认领 引用
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作者 李明川 叶明露 《西华师范大学学报（自然科学版）》 2020年第1期46-51,共6页
Forward-Backward分裂算法是求解极大单调算子和问题以及极小化具有可分结构的凸函数和问题的有效算法。本文利用该算法在Hilbert空间中构造出了求解双层优化问题的分裂算法。与已有文献相比,所提算法不仅在参数的选取上更加灵活,而且... Forward-Backward分裂算法是求解极大单调算子和问题以及极小化具有可分结构的凸函数和问题的有效算法。本文利用该算法在Hilbert空间中构造出了求解双层优化问题的分裂算法。与已有文献相比,所提算法不仅在参数的选取上更加灵活,而且本文还证明了该算法生成的点列能收敛到双层优化问题的解。 展开更多
关键词 极大单调算子 双层优化 非扩张映射 Forward-Backward算法 弱收敛列
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Identification and Prediction of Key Technologies in Ginsenosides Based on Genetic Knowledge Persistence Algorithm 认领 引用
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作者 Li Qian Zhang Wenfeng Yuan Hongmei 《Asian Journal of Social Pharmacy》 CAS 2025年第1期68-79,共12页
Objective To study the key technologies in the field of ginsenosides and to offer a guide for the future development ginsenosides through the main path identification method based on genetic knowledge persistence algo... Objective To study the key technologies in the field of ginsenosides and to offer a guide for the future development ginsenosides through the main path identification method based on genetic knowledge persistence algorithm(GKPA).Methods The global ginsenoside invention authorized patents were used as the data source to construct a ginsenoside patent self-citation network,and to identify high knowledge persistent patents(HKPP)of ginsenoside technology based on the GKPA,and extract its high knowledge persistence main path(HKPMP).Finally,the genetic forward and backward path(GFBP)was used to search the nodes on the main path,and draw the genetic forward and backward main path(GFBMP)of ginsenoside technology.Results and Conclusion The algorithm was applied to the field of ginsenosides.The research results show the milestone patents in ginsenosides technology and the main evolution process of three key technologies,which points out the future direction for the technological development of ginsenosides.The results obtained by this algorithm are more interpretable,comprehensive and scientific. 展开更多
关键词 ginsenoside genetic knowledge persistence algorithm(GKPA) high knowledge persistence patent(HKPP) genetic forward and backward path(GFBP) main path analysis
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CROSS-BORDER TRANSFER OF THE COMPANY SEAT: ONE STEP FORWARD, FEW STEPS BACKWARD 认领 引用
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作者 Hana Horak Kosjenka Dumandic 《US-China Law Review》 2017年第10期711-728,共18页
Cross-border transfer of the company seat for more than decade wasand still is hot and unresolved topic in EU Company Law. Freedom ofestablishment is indisputable cornerstone of EU company law and InternalMarket enshr... Cross-border transfer of the company seat for more than decade wasand still is hot and unresolved topic in EU Company Law. Freedom ofestablishment is indisputable cornerstone of EU company law and InternalMarket enshrined in Articles 49 and 54 of the Treaty on the Functioning ofthe European Union （TFEU） but still the company＇s cross border mobilityis unsolved. The company transfer of the seat is closely connected withdifferent Member States legal tradition in relation with the two different ＂seat theories＂ that apply. By the practice of the European Court of Justiceboth seat theories ＂the real seat theory＂ and ＂the incorporation theory＂are proclaimed as in line with the EU law. Nevertheless, the process ofcross border transfer of the seat occurs as compelling problem for thecross-border company mobility. In most Member States at the moment thecross border transfer of the company seat requires the winding-up of thecompany and establishing the new one in the other Member State. Thisprocedure leads to the loss of legal and business continuity and nationalapproaches to this issue differ. 展开更多
关键词 CROSS-BORDER TRANSFER OF THE COMPANY SEAT ONE STEP FORWARD FEW STEPS BACKWARD
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基于船载走航的长江湖北段PM2.5特征及来源 认领 引用 被引量：1
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作者 郑煌 陈楠 +2 位作者 郑淑睿 许可 郑明明 《中国环境科学》 EI CAS CSCD 北大核心 2026年第2期666-675,共10页
2024年8月28日~9月3日,利用船载测量仪器对长江湖北段大气污染物浓度进行观测,获得了江面上大气污染浓度以及细颗粒物(PM2.5)化学组分信息.结果表明,走航期间,长江湖北段上CO、NO2、O3和SO2平均浓度分别为(0.75±0.22)m... 2024年8月28日~9月3日,利用船载测量仪器对长江湖北段大气污染物浓度进行观测,获得了江面上大气污染浓度以及细颗粒物(PM2.5)化学组分信息.结果表明,走航期间,长江湖北段上CO、NO2、O3和SO2平均浓度分别为(0.75±0.22)mg/m3、(19.87±12.77)µg/m3、(74.23±39.22)µg/m3和(21.98±8.81)µg/m3,均未超过《环境空气质量标准》一级标准.走航期间PM2.5质量浓度为(35.84±12.08)µg/m3,其中有机物占比最高((21.94±7.36)%),其次为SO42-((20.53±10.31)%)、NO3-((19.88±12.29)%)和NH4+((12.80±4.70)%).利用受体模型解析得到PM2.5来源于二次无机气溶胶、船舶排放、生物质燃烧和工业排放,其贡献率分别为(47.86±6.17)%、(26.61±3.32)%、(18.29±6.57)%和(8.38±4.68)%.对比走航观测和陆地超站观测数据发现,江面上的二次生成作用更强.耦合FLEXPART后向模拟和PM2.5排放清单,计算得到研究区域内各格点对走航路线上PM2.5浓度的相对贡献,长江沿岸的贡献率为76.90%,其他区域的贡献为23.10%.FLEXPART前向模拟结果表明,船舶排放对长江沿线的影响高于其他地区. 展开更多
关键词 大气污染物 走航 长江 源解析 前向模拟 后向轨迹
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基于遗传算法与神经网络的逆向侵蚀管涌通道表征方法 认领 引用 被引量：1
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作者 梁越 饶育锋 +5 位作者 赵卓越 许彬 杨晓霞 夏日风 邓惠丹 RASHID Hafiz Aqib 《岩土力学》 EI CAS CSCD 北大核心 2026年第1期323-336,共14页
堤防是应用最广泛且有效的防洪工程措施之一。然而,由于堤防老化、加固措施不力以及复杂的地质条件,在汛期常发生管涌等险情,导致重大且往往难以修复的损失。以双层堤基逆向侵蚀管涌(backward erosion piping,简称BEP)为研究对象,开展... 堤防是应用最广泛且有效的防洪工程措施之一。然而,由于堤防老化、加固措施不力以及复杂的地质条件,在汛期常发生管涌等险情,导致重大且往往难以修复的损失。以双层堤基逆向侵蚀管涌(backward erosion piping,简称BEP)为研究对象,开展遗传算法(genetic algorithm,简称GA)优化的反向传播(back propagation,简称BP)神经网洛对逆向侵蚀管涌通道进行刻画研究。主要研究工作及成果包括:(1)通过非均质含水层中BEP的数值模拟构建训练数据集,并利用室内沙槽管涌试验验证了该数据集的可靠性;(2)从BEP室内试验的Ⅱ、Ⅲ和Ⅳ组数据中提取水头H和渗透系数K数据,进行数据集扩充,并优化GA-BP模型以表征I组试验结果,结果表明优化后的模型能更准确地刻画K≤1.0 cm/s的区域;(3)利用优化后的GA-BP模型表征BEP通道的发展过程。结果表明,该模型能准确捕捉总体发展趋势,但在表征通道位置和尺寸方面与实际条件仍存在微小偏差。综上所述,研究为表征BEP提供了有效工具,并证明了GA-BP网络模型在该领域的实际应用潜力。 展开更多
关键词 逆向侵蚀管涌 管涌通道 BP神经网络 遗传算法 渗透系数
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采用前瞻贪婪算法的柔性配电网快速供电恢复方法 认领 引用
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作者 晋萃萃 张磐 +3 位作者 刘涛 祖国强 王智爽 张超雄 《电力系统及其自动化学报》 CSCD 北大核心 2026年第1期105-114,共10页
针对高比例可再生能源接入配电网导致的供电恢复难题,提出一种柔性配电网快速供电恢复方法。构建了考虑二次停电约束与源荷时序波动的柔性配电网供电恢复模型,将孤岛划分转化为多时间尺度协同优化问题,充分计及储能动态特性、分布式电... 针对高比例可再生能源接入配电网导致的供电恢复难题,提出一种柔性配电网快速供电恢复方法。构建了考虑二次停电约束与源荷时序波动的柔性配电网供电恢复模型,将孤岛划分转化为多时间尺度协同优化问题,充分计及储能动态特性、分布式电源出力波动及负荷时序变化,并引入二次停电约束以保障供电持续性。采用前瞻贪婪算法实现配电网最大供电恢复区域的快速搜索与拓扑压缩,通过多步预判机制避免局部最优;建立基于电力校核的双层优化模型,结合Kruskal算法进行孤岛结构调整,确保孤岛满足辐射状运行约束。在改进的PG&E 69节点系统中进行验证,结果表明所提方法能够最大化恢复重要负荷供电,减少二次停电风险,显著提升求解速度,为智能配电网的故障自愈与可持续发展提供了关键技术支撑。 展开更多
关键词 配电网 孤岛划分 供电恢复 前瞻贪婪算法
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WSN中计及信誉度的人工蜂群恶意节点识别策略 认领 引用
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作者 滕志军 谷金亮 +2 位作者 崔瑶瑶 朱思安 庞宝贺 《哈尔滨工业大学学报》 EI CAS CSCD 北大核心 2026年第3期181-189,共9页
在无线传感器网络(WSN)复杂的应用环境中,为抵御恶意节点发起的选择性转发攻击和不诚实建议攻击、提高网络安全性能,在人工蜂群(ABC)算法的基础上,提出一种计及信誉度的人工蜂群无线传感器网络恶意节点识别策略(CR-ABC)。借助模糊信任模... 在无线传感器网络(WSN)复杂的应用环境中,为抵御恶意节点发起的选择性转发攻击和不诚实建议攻击、提高网络安全性能,在人工蜂群(ABC)算法的基础上,提出一种计及信誉度的人工蜂群无线传感器网络恶意节点识别策略(CR-ABC)。借助模糊信任模型,融合模糊综合评价机制,综合通信特征、数据属性、物理属性3个方面的影响因素计算节点综合信任值,提高信誉模型的检测精度;引入建议偏差值函数和交互指数偏差值函数,利用ABC算法优化模糊信任模型,确保在恶意节点数量较多时,系统仍保持较高的识别率和较低的误判率。仿真结果表明,CR-ABC对选择性转发攻击的识别率可达90%以上,对正常节点误判率低于6%;对于不诚实建议攻击,即使不诚实节点的数量占比达到50%,CR-ABC仍能保持优异的识别性能,可有效提高复杂环境下WSN的安全性和可靠性。 展开更多
关键词 无线传感器网络 信誉度 人工蜂群算法 选择性转发攻击 不诚实建议攻击
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多次前向一次后向黏声双程波叠前偏移方法 认领 引用
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作者 孙华超 孙建国 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2026年第7期3188-3204,共17页
为解决传统黏声De Wolf近似单程波偏移方法在构造陡倾角情况下成像精度低以及补偿效果差等问题,本文将黏声介质De Wolf近似单程波反Q偏移算子应用到双程波偏移方法中,利用两个单程波偏移算子实现多次前向一次后向黏声双程波偏移成像方法... 为解决传统黏声De Wolf近似单程波偏移方法在构造陡倾角情况下成像精度低以及补偿效果差等问题,本文将黏声介质De Wolf近似单程波反Q偏移算子应用到双程波偏移方法中,利用两个单程波偏移算子实现多次前向一次后向黏声双程波偏移成像方法,进而克服基于De Wolf近似法的单程波偏移算子固有的倾角误差限制.在算法实现的基础上,首先,开展了算子的脉冲响应测试和理论模型试算研究.数值研究表明:(1)基于两个单向传播补偿算子的双程波偏移方法可以有效地补偿地震波的衰减;相对于黏声单程波偏移方法,多次前向一次后向黏声双程波偏移结果中陡倾角构造的成像精度更高,补偿效果更好.(2)由于多次前向一次后向散射波场可以在计算过程中分离出来,与基于差分算子的逆时偏移方法相比,成像结果中无低频噪声问题且计算效率更高.(3)该方法偏移剖面中的部分陡倾角成像精度相对较低,其原因是De Wolf近似两种近似处理(局部Born近似和重整化Green函数利用均匀介质背景Green函数代替)导致算子在强扰动介质中计算误差相对较大(特别是高角度传播时).其次,为了分析算法的实用性,利用实际数据进行算法测试.最后,围绕含噪声数据的偏移测试以及频率域算法稳定性问题展开讨论.上述研究结果进一步验证了算法的有效性,可为复杂介质构造中的偏移成像提供理论基础. 展开更多
关键词 De Wolf近似 多次前向一次后向 双程波叠前偏移 振幅补偿 陡倾角构造成像
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