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On the Linear Convergence of the Approximate Proximal Splitting Method for Non-smooth Convex Optimization

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Journal of the Operations Research Society of China 2014年第2期2卷 123-141页

作者： Mojtaba Kadkhodaie Maziar Sanjabi zhi-quan luo University of Minnesota MinneapolisMNUSA

Consider the problem of minimizing the sum of two convex functions,one being smooth and the other *** this paper,we introduce a general class of approximate proximal splitting(APS)methods for solving such minimization *** in the APS class include many well-known algorithms such as the proximal splitting method,the block coordinate descent method(BCD),and the approximate gradient projection methods for smooth convex *** establish the linear convergence of APS methods under a local error bound *** the latter is known to hold for compressive sensing and sparse group LASSO problems,our analysis implies the linear convergence of the BCD method for these problems without strong convexity assumption.

关键词： Convex optimization Proximal splitting method Block coordinate descent method Convergence rate analysis Local error bound

On the Linear Convergence of a Proximal Gradient Method for a Class of Nonsmooth Convex Minimization Problems

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Journal of the Operations Research Society of China 2013年第2期1卷 163-186页

作者： Haibin Zhang Jiaojiao Jiang zhi-quan luo College of Applied Science Beijing University of TechnologyBeijing 100124China Department of Electrical and Computer Engineering University of MinnesotaMinneapolisMN 55455USA

We consider a class of nonsmooth convex optimization problems where the objective function is the composition of a strongly convex differentiable function with a linear mapping,regularized by the sum of both l1-norm and l2-norm of the optimization *** class of problems arise naturally from applications in sparse group Lasso,which is a popular technique for variable *** effective approach to solve such problems is by the Proximal Gradient Method(PGM).In this paper we prove a local error bound around the optimal solution set for this problem and use it to establish the linear convergence of the PGM method without assuming strong convexity of the overall objective function.

关键词： Proximal gradient method Error bound Linear convergence Sparse group I asso

Measurements of the equivalent thicknesses of three-dimensional spiral galactic disks

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Research in Astronomy and Astrophysics 2009年第8期9卷 883-887页

作者： Gang Li zhi-quan luo Qiu-He Peng Institute of Theoretical Physics China West Normal University Nanchong 637002 China Department of Astronomy Nanjing University Nanjing 210093 China

Spiral arms are fitted after the data from the latest spiral galactic images released by the Sloan Digital Sky Survey are processed. Equivalent thicknesses of 42 spiral galactic disks are derived, which increase the f... 详细信息

关键词： galaxies spiral -- Galaxy disk

Collapse Velocity and Prompt Explosion for the Presupernova Model Ws15M_⊙

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Chinese Journal of Astronomy and Astrophysics 2006年第4期6卷 455-460页

作者： zhi-quan luo Men-quan Liu Qiu-He Peng Zuo-Heng Xie Institute of Theoretical Physics China West Normal University Nanchong 637002 Department of Physics Sichuan University Chengdu 610065 Department of Astronomy Nanjing University Nanjing 210093 Institute of Applied Mathematics Chinese Academy of Sciences Beijing 100080

For the presupernova modelWs15M⊙, we re-calculate the electron capture （EC） timescale and hydrodynamical （HD） timescale. We found that the EC timescale can be smaller than the HD timescale in the inner region of the collapse iron core at the moment immediately before the shock wave bounce. The change in these two timescales at the late stage of core collapse is expected to affect the collapse velocity. If the late-time collapse velocity is artificially increased by a small quantity, then prompt explosion of the supernova may happen. Further calculations are still needed to check the plausibility of the acceleration mechanism caused by the faster EC process.

关键词： star: supernova-- nuclear reaction -- nucleosynthesis

The Origin of Glitches in Pulsars—Phase Oscillation between Anisotropic Superfluid and Normal State of Neutrons in Neutron Stars

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Chinese Journal of Astronomy and Astrophysics 2006年第3期6卷 297-304页

作者： Qiu-He Peng zhi-quan luo Chih-Kang Chou School of Physics and Electronic Information China West Normal University Nanchong 637002 Department of Astronomy Nanjing University Nanjing 210093 Department of Physics Sichuan University Chengdu 610065 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

Considering neutron star heating by magnetic dipole radiation from ^3PF2 superfluid neutron vortices inside the star, we propose a neutron phase oscillation model between the normal neutron Fermi fluid and the ^3PF2 superfluid neutron vortices at the transition temperature of Ttrans = （2 - 3）× 10^8 K. With this model we can qualitatively explain most of the observations on pulsar glitches up to date.

关键词： stars: neutron - pulsars: general

V551 Aur,an oEA binary with g-mode pulsations?

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Research in Astronomy and Astrophysics 2012年第6期12卷 671-677页

作者： Nian Liu Xiao-Bin Zhang An-Bin Ren Li-Cai Deng zhi-quan luo Institute of Theoretical Physics China West Normal University Nanchong 637002 China National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We present time-series CCD photometry of V551 Aur, an eclipsing binary located in the open cluster NGC 2126 that shows δ Scuti-like pulsations. Complete covered light curves in theBand V bands were obtained with high-precision over nine nights. Based on them, a revised orbital period and the first photometric solutions were determined. Our eclipsing light-curve synthesis reveals a detached configura- tion for the binary system with a mass-ratio of about 0.73, and the mean density of the pulsating primary component was deduced to be about （0.532±0.005）ρ. A fre- quency analysis of the eclipse-subtracted light curve yields two reliable frequencies at f1=7.727013（c/d） and f2=15.45403（c/d）, respectively. With the help of the derived mean density, mode identification was performed. The result suggests that the primary component of V551 Aur is very probably g-mode oscillations.

关键词： stars: binaries: eclipsing -- stars: oscillations -- stars: individual (V551Aur) -- open cluster: individual (NGC 2126)

The high-amplitude δ Scuti variable CY Aqr is probably a triple system

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Research in Astronomy and Astrophysics 2016年第6期16卷 105-112页

作者： Wei-Jing Fang zhi-quan luo Xiao-Bin Zhang Li-Cai Deng Kun Wang Yang-Ping luo Yang Pan Yin-Jiang Peng Physics and Space Science College China West Normal University Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of Sciences

Data representing 864 times of light maxima of the high-amplitude δ Scuti star CY Aqr were col- lected from the literature, based on which, long-term period changes of the variable star were investigated. A revised period and new ephemerides were given for the pulsating star. Remarkable cyclic variations were found in the O - C residuals which can be attributed to the light-time effects due to probable unseen com- ponents of the object. By using Kopal＇s method, the orbital parameters of the supposed component stars were derived. The solution suggests that CY Aqr is very probably in a triple system orbited eccentrically by two low-mass companions with periods of 54.2 and 47.3 yr. The lower limits on masses were estimated as 0.04 Me and 0.02 Me, respectively, for the two hidden companions.

关键词： methods data analysis -- stars variables δ Scuti -- stars individual (CY Aqr)

The first CCD photometric study of the open cluster NGC 744

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Research in Astronomy and Astrophysics 2018年第11期18卷 89-96页

作者： Kun Wang Li-Cai Deng zhi-quan luo Zheng-Zhou Yan Qi-Li Liu Jin-Jiang Sun Qiang Zhou Department of Astronomy China West Normal University Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Purple Mountain Observatory Chinese Academy of Sciences

We present the first CCD photometric observations of open cluster NGC 744, as part of the 50 BiN Open Cluster Survey. The color-magnitude diagrams of this cluster were derived from absolute BV RI photometry on a good photometric night. A brief isochrone fitting gives a distance modulus of(m-M)V= 11.58±0.2 and a reddening of E(B-V) = 0.35±0.05 with an age of log t = 8.30±*** carefully examining the BV time-series data, we discovered four new variable stars in a 20′×20′field around the cluster. We classified them as three eclipsing binary stars and one δ Scuti pulsating star,mainly based on the light-curve shape, the detected periods and the positions on the color-magnitude diagrams.

关键词： open clusters and associations: individual(NGC 744) stars: variables: general

Sequential Inverse Optimal Control of Discrete-Time Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 608-621页

作者： Sheng Cao zhiwei luo Changqin quan the Graduate School of System Informatics Kobe University Kobe 657-8501Japan

This paper presents a novel sequential inverse optimal control(SIOC)method for discrete-time systems,which calculates the unknown weight vectors of the cost function in real time using the input and output of an optimally controlled discrete-time *** proposed method overcomes the limitations of previous approaches by eliminating the need for the invertible Jacobian *** calculates the possible-solution spaces and their intersections sequentially until the dimension of the intersection space decreases to *** remaining one-dimensional vector of the possible-solution space’s intersection represents the SIOC *** paper presents clear conditions for convergence and addresses the issue of noisy data by clarifying the conditions for the singular values of the matrices that relate to the possible-solution *** effectiveness of the proposed method is demonstrated through simulation results.

关键词： Inverse optimal control promised calculation step sequential calculation