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Fast Model-Based X-Ray CT Reconstruction Using Spatially Nonhomogeneous ICD Optimization

IEEE TRANSACTIONS ON IMAGE PROCESSING 2011年第1期20卷 161-175页

作者： Yu, Zhou Thibault, Jean-Baptiste Bouman, Charles A. Sauer, Ken D. Hsieh, Jiang Purdue Univ Sch Elect & Comp Engn W Lafayette IN 47907 USA Univ Notre Dame Dept Elect Engn Notre Dame IN 46556 USA GE Healthcare Technol Waukesha WI 53188 USA

Recent applications of model-based iterative reconstruction (MBIR) algorithms to multislice helical CT reconstructions have shown that MBIR can greatly improve image quality by increasing resolution as well as reducing noise and some artifacts. However, high computational cost and long reconstruction times remain as a barrier to the use of MBIR in practical applications. Among the various iterative methods that have been studied for MBIR, iterative coordinate descent (ICD) has been found to have relatively low overall computational requirements due to its fast convergence. This paper presents a fast model-based iterative reconstruction algorithm using spatially nonhomogeneous ICD (NHICD) optimization. The NH-ICD algorithm speeds up convergence by focusing computation where it is most needed. The NH-ICD algorithm has a mechanism that adaptively selects voxels for update. First, a voxel selection criterion VSC determines the voxels in greatest need of update. Then a voxel selection algorithm VSA selects the order of successive voxel updates based upon the need for repeated updates of some locations, while retaining characteristics for global convergence. In order to speed up each voxel update, we also propose a fast 1-D optimization algorithm that uses a quadratic substitute function to upper bound the local 1-D objective function, so that a closed form solution can be obtained rather than using a computationally expensive line search algorithm. We examine the performance of the proposed algorithm using several clinical data sets of various anatomy. The experimental results show that the proposed method accelerates the reconstructions by roughly a factor of three on average for typical 3-D multislice geometries.

关键词： Computed tomography coordinate descent iterative algorithm model based iterative reconstruction (MBIR)

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An iterative algorithm for approximating convex minimization problem

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APPLIED MATHEMATICS AND COMPUTATION 2007年第1期188卷 648-656页

作者： Yao, Yonghong Liou, Yeong-Cheng Yao, Jen-Chih Natl Sun Yat Sen Univ Dept Appl Math Kaohsiung 804 Taiwan Cheng Shiu Univ Dept Informat Management Kaohsiung 833 Taiwan Tianjin Polytech Univ Dept Math Tianjin 300160 Peoples R China

We suggest and analyze an iterative algorithm without the assumption of any type of commutativity on an infinite family of nonexpansive mappings. We show that the proposed iterative algorithm converges to the unique minimizer of some quadratic function over the common fixed point sets of an infinite family of nonexoansive mappings. Our result extend and improve many results announced by many authors. (C) 2006 Elsevier Inc. All rights reserved.

关键词： nonexpansive mapping fixed point convex minimization problem iterative algorithm

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Adaptive tuning of buffer pool size in database server based on iterative algorithm

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IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 2007年第2期E90D卷 594-597页

作者： Shimizu, Junya Diao, Yixin IBM Res Corp Tokyo Res Lab Yamato 2428502 Japan IBM Corp Thomas J Watson Res Ctr Yorktown Hts NY 10598 USA

One of the system greatly affecting the performance of a database server is the size-division of buffer pools. This letter proposes an adaptive control method of the buffer pool sizes. This method obtains the nearly o... 详细信息

关键词： database server buffer pool performance control extended Kalman filtering iterative algorithm

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General system of (A, η)-monotone variational inclusion problems based on generalized hybrid iterative algorithm

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NONLINEAR ANALYSIS-HYBRID SYSTEMS 2007年第3期1卷 326-335页

作者： Verma, Rm U. Univ Toledo Dept Math Toledo OH 43606 USA

First a new system of nonlinear set-valued variational inclusions involving (A, eta)-monotone mappings in Hilbert spaces is introduced and then its solvability is explored. Based on the general resolvent operator method associated with (A, eta)-monotone mappings, approximation solvability of this system of nonlinear set-valued variational inclusions is established. The convergence analysis is discussed in detail. The obtained results generalize a number of results on nonlinear variational inclusion systems. (C) 2006 Elsevier Ltd. All rights reserved.

关键词： (A, eta)-monotone mapping System of nonlinear set-valued variational inclusions Resolvent operator method iterative algorithm

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Simple "Residual-Norm" Based algorithms, for the Solution of a Large System of Non-Linear Algebraic Equations, which Converge Faster than the Newton's Method

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CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES 2011年第3期71卷 279-304页

作者： Liu, Chein-Shan Atluri, Satya N. Natl Taiwan Univ Dept Civil Engn Taipei 10764 Taiwan Univ Calif Irvine Ctr Aerosp Res & Educ Irvine CA USA

For solving a system of nonlinear algebraic equations (NAEs) of the type: F(x) = 0, or F(i)(x(j)) = 0, i, j = 1, ..., n, a Newton-like algorithm has several drawbacks such as local convergence, being sensitive to the initial guess of solution, and the time-penalty involved in finding the inversion of the Jacobian matrix partial derivative F(i)/partial derivative x(j). Based-on an invariant manifold defined in the space of (x, t) in terms of the residual-norm of the vector F(x), we can derive a gradient-flow system of nonlinear ordinary differential equations (ODEs) governing the evolution of x with a fictitious time-like variable t as an independent variable. We can prove that in the present novel Residual-Norm Based algorithms (RNBAs), the residual-error is automatically decreased to zero along the path of x(t). More importantly, we have derived three iterative algoritms which do not involve the fictitious time and its stepsize Delta t. We apply the three RNBAs to several numerical examples, revealing exponential convergences with different slopes and displaying the high efficiencies and accuracies of the present iterative algorithms. All the three presently proposed RNBAs: (i) are easy to implement numerically, (ii) converge much faster than the Newton's method, (iii) do not involve the inversion of the Jacobian partial derivative F(i)/partial derivative x(j), (iv) are suitable for solving a large system of NAEs, and (v) are purely iterative in nature.

关键词： Nonlinear algebraic equations Non-Linear Ordinary Differential Equations Non-Linear Partial Differential Equations Residual-Norm Based algorithms (RNBAs) Fictitious time integration method (FTIM) iterative algorithm

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A new iterative algorithm for approximating common fixed points for asymptotically nonexpansive mappings

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FIXED POINT THEORY AND APPLICATIONS 2007年第1期2007卷 1-10页

作者： Zhou, H. Y. Cho, Y. J. Kang, S. M. N China Elect Power Univ Dept Appl Math Baoding 071003 Peoples R China Gyeongsang Natl Univ Dept Math Educ Coll Nat Sci Chinju 660701 South Korea Gyeongsang Natl Univ RINS Coll Nat Sci Chinju 660701 South Korea

Suppose that K is a nonempty closed convex subset of a real uniformly convex and smooth Banach space E with P as a sunny nonexpansive retraction. Let T-1, T-2 : K -> E be two weakly inward and asymptotically nonexpansive mappings with respect to P with sequences {K-n},{l(n)} subset of [1,infinity), lim(n ->infinity) k(n) = 1, lim(n ->infinity) l(n) = 1, F(T-1) boolean AND F(T-2) = {x is an element of K : T(1)x = T(2)x = x} not equal empty set, respectively. Suppose that {x(n)} is a sequence in K generated iteratively by x(1) is an element of K, x(n+1) = alpha(n)x(n) + beta(n)(PT1)(n) x(n) + gamma(n)(PT2)(n) x(n), for all n >= 1, where {alpha(n)}, {beta(n)}, and {gamma(n)} are three real sequences in [epsilon, 1-epsilon] for some epsilon > 0 which satisfy condition alpha(n) + beta(n) + gamma(n) = 1. Then, we have the following. (1) If one of T-1 and T-2 is completely continuous or demicompact and Sigma(infinity)(n=1)(k(n) - 1) < infinity, Sigma(infinity)(n=1)(l(n) - 1) < infinity, then the strong convergence of {x(n)} to some q is an element of F(T-1) boolean AND F(T-2) is established. ( 2) If E is a real uniformly convex Banach space satisfying Opial's condition or whose norm is Frechet differentiable, then the weak convergence of {x(n)} to some q is an element of F(T-1) boolean AND F(T-2) is proved.

关键词： .NONEXPANSIVE MAPPINGS sunny nonexpansive retraction asymptotically limN iterative algorithm Convex Subset nonempty closed WEAKLY INWARD real uniformly convex uniformly convex Banach mappings with respect Kn ln

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AN ACCELERATED ORDERED SUBSETS RECONSTRUCTION algorithm FOR X-RAY CONE-BEAM CT

AN ACCELERATED ORDERED SUBSETS RECONSTRUCTION ALGORITHM FOR ...

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第十三届国际体视学大会

作者： Xing Zhao~1,Jingjing Hu~2 1.School of Mathematical Sciences,Capital Normal University,Beijing 100048,China 2.Department of Computer Science,Beijing Institute of Technology,Beijing 100081,China

iterative image reconstruction algorithms have many advantages over analytical image reconstruction algorithms. The OSEM(ordered subsets EM) iterative algorithm has enjoyed considerable interest for computed tomography due to its acceleration of the ML-EM *** with the conventional OSEM algorithm,the OS method RAMLA(row action ML algorithm) can not only bring about significant acceleration in the iterative reconstruction, but also outperform OSEM in convergence ***,the algorithm requires a judicious choice of a user-specified relaxation parameter,which is sometimes very *** this paper,we present an accelerated ordered subsets reconstruction algorithm for X-ray cone-beam *** algorithm is founded on RAMLA approach, but avoids the problem of user-specified relaxation ***,by increasing the step size of the correction factor,the algorithm achieves a great deal of acceleration in convergence *** advantages of the method are verified by the experiment of the 3D image iterative reconstruction of FORBILD's head phantom.

关键词： computed tomography cone-beam ordered subsets iterative algorithm

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iterative solutions for general coupled matrix equations with real coefficients

Iterative solutions for general coupled matrix equations wit...

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American Control Conference

作者： Li Xie Huizhong Yang Yanjun Liu Feng Ding Key Laboratory of Advanced Process Control for Light Industry (Ministry of Education) and the Control Science and Engineering Research Center Jiangnan University Wuxi 214122 P.R. China

ISBN: (纸本)9781457700811

This paper applies the hierarchical identification principle and the gradient search method to study iterative solutions for a class of general coupled matrix equations with real coefficients. As long as the convergence factors are appropriately chosen, the proposed algorithms for any initial values can provide iterative solutions that are arbitrarily close to the unique solutions of the equations. Two numerical examples are given to demonstrate the effectiveness of the proposed algorithms.

关键词： Coupled matrix equations hierarchical identification gradient search iterative algorithm estimation

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Mathematics Stencil of Finite Difference Scheme and its Application to Parabolic Equations

Mathematics Stencil of Finite Difference Scheme and its Appl...

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2011 4th IEEE International Conference on Computer Science and Information Technology(ICCSIT 2011)

作者： Yang Liu School of Science, Wuhan University of Technology, Wuhan,China Liang Zhang School of Science, Wuhan University of Technology, Wuhan,China

In this paper we investigate the parallel iterative algorithm of parabolic *** we introduce the concept of mathematics stencil to the Crank-Nicolson difference scheme of parabolic equation and the stencil elimination procedure,then we construct an iterative algorithm which has intrinsic *** convergence theory is discussed in ***,some numerical experiments are provided to show the efficiency of the new algorithm.

关键词： iterative algorithm stencil elimination method finite difference parallel parabolic equation

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An Efficient Method for Strain Fatigue Reliability Analysis

An Efficient Method for Strain Fatigue Reliability Analysis

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2011 9th International Conference on Reliability,Maintainability and Safety(第九届国际可靠性、维修性、安全性会议 ICRMS'2011)

作者： Qin Liu Zhili Sun Yunpeng Qian Dan Wang Department of Mechanical Engineering and Automation Northeastern University Shenyang 110004 China North China System Engineering Institute CNGC Beijing 100089 China

Based on Manson-Coffin Equation, a strain fatigue reliability model was built Because of high nonlinear degree, the first-order reliability method has convergence difficulty for the model. An efficient iterative algorithm for strain fatigue reliability is proposed by using automatic step adjustment method etc., and the numerical results show that the proposed method has a good convergence compared with FORM.

关键词： strain fatigue reliability iterative algorithm automatic step adjustment

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