中国科学院机构知识库网格系统: 检索

Inexact Newton-type methods based on Lanczos orthonormal method and application for full waveform inversion 期刊论文 OAI收割
Inverse Problems, 2020, 卷号: 36, 期号: 11
作者: He,Qinglong; Wang,Yanfei

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收藏 | 浏览/下载：33/0 | 提交时间：2021/01/08

inexact Newton-type methods Lanczos orthonormal method full waveform inversion Krylov subspace methods adjoint-state method

Complex-Valued Discrete-Time Neural Dynamics for Perturbed Time-Dependent Complex Quadratic Programming With Applications 期刊论文 OAI收割
IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS, 2020, 卷号: 31, 期号: 9, 页码: 3555-3569
作者: Qi, Yimeng; Jin, Long; Wang, Yaonan; Xiao, Lin; Zhang, Jiliang

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收藏 | 浏览/下载：42/0 | 提交时间：2021/01/07

Computational modeling Convergence Mathematical model Recurrent neural networks Perturbation methods Robots Numerical models Complex domain discrete-time neural dynamics (DTND) quasi-Newton Broyden-Fletcher-Goldfarb-Shanno (BFGS) quadratic programming (QP)

Highly Accurate Numerical Schemes for Stochastic Optimal Control Via FBSDEs 期刊论文 OAI收割
NUMERICAL MATHEMATICS-THEORY METHODS AND APPLICATIONS, 2020, 卷号: 13, 期号: 2, 页码: 296-319
作者: Fu, Yu; Zhao, Weidong; Zhou, Tao

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收藏 | 浏览/下载：53/0 | 提交时间：2020/05/24

Forward backward stochastic differential equations stochastic optimal control stochastic maximum principle projected quasi-Newton methods

An underlying clock in the extreme flip-flop state transitions of the black hole transient Swift J1658.2-4242 期刊论文 OAI收割
Astronomy and Astrophysics, 2020, 卷号: 641, 页码: A101
作者: HXMT

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收藏 | 浏览/下载：58/0 | 提交时间：2022/02/08

accretion accretion disks black hole physics X-rays: binaries time Astrophysics - High Energy Astrophysical Phenomena Abstract:
Aims: Flip-flops are top-hat-like X-ray flux variations, which have been observed in some transient accreting black hole binary systems, and feature simultaneous changes in the spectral hardness and the power density spectrum (PDS). They occur at a crucial time in the evolution of these systems, when the accretion disc emission starts to dominate over coronal emission. Flip-flops remain a poorly understood phenomenon, so we aim to thoroughly investigate them in a system featuring several such transitions.
Methods: Within the multitude of observations of Swift J1658.2-4242 during its outburst in early 2018, we detected 15 flip-flops, enabling a detailed analysis of their individual properties and the differences between them. We present observations by XMM-Newton, NuSTAR, Astrosat, Swift, Insight-HXMT, INTEGRAL, and ATCA. We analysed their light curves, searched for periodicities, computed their PDSs, and fitted their X-ray spectra, to investigate the source behaviour during flip-flop transitions and how the interval featuring flip-flops differs from the rest of the outburst.
Results: The flip-flops of Swift J1658.2-4242 are of an extreme variety, exhibiting flux differences of up to 77% within 100 s, which is much larger than what has been seen previously. We observed radical changes in the PDS simultaneous with the sharp flux variations, featuring transitions between the quasi-periodic oscillation types C and A, which have never been observed before. Changes in the PDS are delayed, but more rapid than changes in the light curve. Flip-flops occur in two intervals within the outburst, separated by about two weeks in which these phenomena were not seen. Transitions between the two flip-flop states occurred at random integer multiples of a fundamental period of 2.761 ks in the first interval and 2.61 ks in the second. Spectral analysis reveals the high and low flux flip-flop states to be very similar, but distinct from intervals lacking flip-flops. A change of the inner temperature of the accretion disc is responsible for most of the flux difference in the flip-flops. We also highlight the importance of correcting for the influence of the dust scattering halo on the X-ray spectra.

AN EFFICIENT GAUSS-NEWTON ALGORITHM FOR SYMMETRIC LOW-RANK PRODUCT MATRIX APPROXIMATIONS 期刊论文 OAI收割
SIAM JOURNAL ON OPTIMIZATION, 2015, 卷号: 25, 期号: 3, 页码: 1571-1608
作者: Liu, Xin; Wen, Zaiwen; Zhang, Yin

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收藏 | 浏览/下载：14/0 | 提交时间：2018/07/30

eigenvalue decomposition singular value decomposition low-rank product matrix approximation Gauss-Newton methods

Frequency multiscale full-waveform velocity inversion 期刊论文 OAI收割
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION, 2015, 卷号: 58, 期号: 1, 页码: 216-228
作者: Zhang WenSheng; Luo Jia; Teng JiWen

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收藏 | 浏览/下载：31/0 | 提交时间：2021/01/14

ABSORBING BOUNDARY-CONDITIONS SEISMIC-REFLECTION DATA FINITE-FREQUENCY DIFFRACTION TOMOGRAPHY ELASTIC INVERSION NEWTON METHODS GAUSS-NEWTON DOMAIN MEDIA MINIMIZATION Acoustic wave equation Frequency multiscale Time domain Full-waveform inversion Velocity BFGS Marmousi model Finite-difference method MPI parallel

Three-sample rotation vector algorithm with angular rate input (EI CONFERENCE) 会议论文 OAI收割
2011 2nd International Conference on Mechanic Automation and Control Engineering, MACE 2011, July 15, 2011 - July 17, 2011, Inner Mongolia, China
作者: Zhang Y.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

In order to research the attitude algorithm with angular rate input under the conical motion a optimal threesample rotation vector algorithm based on single-step Newton backward interpolation is proposed. Using the principle of limited rigid body rotation and the characteristic of angular rate input three-sample rotation vector algorithm is derivated. To minimum attitude errors three-sample rotation vector algorithm is optimized. Three angular rate extraction methods of singlestep entire sample recursion multi-step entire sample and singlestep Newton backward interpolation are proposed. Under the condition of conical motion with semi-cone angle 3 and angular frequency 2rad/s simulation is done. The simulation results show that single-step Newton backward interpolation is superior to the other two methods and its maximum error peak is 0.01 error drift rate is 0.036/h. Experiments in three-axis flying turntable with the same parameters are carried out and the results show that error drift rates of three-channels are less than those of traditional quaternion which are 13.53% 12.08% and 23.68% lower respectively. It also verified that the new algorithm can perform a high accuracy under the conical motion. 2011 IEEE.

Fifth-order iterative method for finding multiple roots of nonlinear equations 期刊论文 OAI收割
NUMERICAL ALGORITHMS, 2011, 卷号: 57, 期号: 3, 页码: 389-398
Li, XW; Mu, CL; Ma, JW; Hou, Linke(侯麟科)

收藏 | 浏览/下载：26/0 | 提交时间：2012/05/09

Nonlinear equation Multiple roots Newton-like method High-order convergence Iterative methods

Fifth-order iterative method for finding multiple roots of nonlinear equations SCI/SSCI论文 OAI收割
2011
Li X. W.; Mu C. L.; Ma J. W.; Hou L. K.

收藏 | 浏览/下载：23/0 | 提交时间：2012/06/08

Nonlinear equation Multiple roots Newton-like method High-order convergence Iterative methods order family convergence derivatives zeros

欧氏度量学习 学位论文 OAI收割
工学博士, 中国科学院自动化研究所: 中国科学院研究生院, 2008
作者: 李伏欣

收藏 | 浏览/下载：35/0 | 提交时间：2015/09/02

度量学习核学习谱方法再生核希尔伯特空间理论表示定理半牛顿法信赖域法信赖域截断牛顿法正则化解路径非线性半定规划 metric learning kernel learning spectral methods RKHS methods half-Newton method conjugate gradient methods trust-region methods truncated Newton methods regularization path nonlinear SDP