检索结果-内蒙古大学图书馆

Space-time finite element procedure with block-iterative algorithm for dam-reservoir-soil interaction during earthquake loading

引用

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING 2019年第3期120卷 263-282页

作者： Sharma, Vikas Fujisawa, Kazunori Murakami, Akira Kyoto Univ Grad Sch Agr Kyoto 6068502 Japan Kyoto Univ Grad Sch Agr Sakyo Ku Kitashirakawa Oiwake Cho Kyoto 6068502 Japan

This paper presents a time-discontinuous Galerkin space-time finite element method for the seismic analysis of dam-reservoir-soil system. For the reservoir domain an auxiliary variable q, a first-order time derivative of hydrodynamic pressure is introduced as the primary unknown. Similarly, velocity is taken as the primary unknown in the solid domain. In this approach, secondary unknowns (displacement and pressure) are computed in a postprocessing step by consistent time integration of the primary unknowns. This arrangement leads to a system of linearly coupled algebraic equations, which is solved with a block-iterative algorithm. In each iteration of the algorithm, two smaller linear systems, ie, one for velocity field and another for the auxiliary field, are solved separately and coupling between these two fields is enforced through iterations. Afterwards, numerical performance of the proposed scheme is demonstrated by solving some benchmark dam-reservoir interaction problems. It is shown that very few iterations are required for the convergence. Lastly, the method is employed to analyze the effects of dynamic interactions on the response of concrete dam to the earthquake loading.

关键词： block-iterative algorithm dam-reservoir-soil interactions dynamic analysis earthquake engineering space-time FEM

来源：评论

学校读者我要写书评

暂无评论

Improved SAGE algorithm for PET image reconstruction using rescaled block-iterative method

Improved SAGE algorithm for PET image reconstruction using r...

引用

26th Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society

作者： Zhu, HQ Zhou, J Shu, HZ Li, SY Luo, LM Southeast Univ Dept Biol Sci & Med Engn Nanjing 210096 Peoples R China

ISBN: (纸本)0780384393

iterative reconstruction methods such as the expectation maximization maximum likelihood (EMML) method can be accelerated by using a resealed block-iterative (RBI) algorithm. It was demonstrated that the space-alternating generalized expectation-maximization (SAGE) algorithm is superior to the EMML due to the following facts: (1) The hidden data spaces can be appropriately chosen and then be used in SAGE algorithm to speed up the convergence rate. (2) SAGE algorithm updates the parameters sequentially which makes its M-step to be treated more easily. In this paper, we present a novel algorithm that combines the RBI algorithm with SAGE algorithm. The convergence property of RBI-SAGE is discussed, and the image quality is assessed with mean absolute error and chi-square error. The experimental results show that the proposed method is more effective than the SAGE algorithm even if the projection data includes statistic noise.

关键词： block-iterative algorithm SAGE algorithm image reconstruction convergence properties

来源：评论

学校读者我要写书评

暂无评论

Asynchronous block-iterative primal-dual decomposition methods for monotone inclusions

引用

MATHEMATICAL PROGRAMMING 2018年第1-2期168卷 645-672页

作者： Combettes, Patrick L. Eckstein, Jonathan UPMC Univ Paris 06 Lab Jacques Louis Lions CNRS UMR 7598 F-75005 Paris France Rutgers State Univ Dept Managemement Sci & Informat Syst Piscataway NJ 08854 USA Rutgers State Univ RUTCOR Piscataway NJ 08854 USA

We propose new primal-dual decomposition algorithms for solving systems of inclusions involving sums of linearly composed maximally monotone operators. The principal innovation in these algorithms is that they are block-iterative in the sense that, at each iteration, only a subset of the monotone operators needs to be processed, as opposed to all operators as in established methods. Flexible strategies are used to select the blocks of operators activated at each iteration. In addition, we allow lags in operator processing, permitting asynchronous implementation. The decomposition phase of each iteration of our methods is to generate points in the graphs of the selected monotone operators, in order to construct a half-space containing the Kuhn-Tucker set associated with the system. The coordination phase of each iteration involves a projection onto this half-space. We present two related methods: the first method provides weakly convergent primal and dual sequences under general conditions, while the second is a variant in which strong convergence is guaranteed without additional assumptions. Neither algorithm requires prior knowledge of bounds on the linear operators involved or the inversion of linear operators. Our algorithmic framework unifies and significantly extends the approaches taken in earlier work on primal-dual projective splitting methods.

关键词： Asynchronous algorithm block-iterative algorithm Duality Monotone inclusion Monotone operator Primal-dual algorithm Splitting algorithm

来源：评论

学校读者我要写书评

暂无评论

A decomposition method for solving multicommodity network equilibria

引用

OPERATIONS RESEARCH LETTERS 2022年第1期50卷 40-44页

作者： Bui, Minh N. North Carolina State Univ Dept Math Raleigh NC 27695 USA

We consider the numerical aspect of the multicommodity network equilibrium problem proposed by Rockafellar in 1995. Our method relies on the flexible monotone operator splitting framework recently proposed by Combette... 详细信息

关键词： Network equilibrium Network flow Traffic assignment Splitting algorithm block-iterative algorithm Monotone operator

来源：评论

学校读者我要写书评

暂无评论

Parallel block-iterative Reconstruction algorithms for Binary Tomography

引用

Electronic Notes in Discrete Mathematics 2005年 20卷 263-280页

作者： Capricelli, Thomas D. Combettes, Patrick L. Laboratoire Jacques-Louis Lions Université Pierre et Marie Curie - Paris 6 75005 Paris France

A convex programming approach to binary tomographic image reconstruction in noisy environments is proposed. Conventional constraints are mixed with new constraints on the sinogram. A convex objective is then minimized over the resulting feasibility set via a parallel block-iterative method. The new constraints involve noise-based confidence regions and a binarity-promoting total variation constraint. © 2005 Elsevier B.V. All rights reserved.

关键词： Binary tomography block-iterative algorithm convex constraints convex programming image reconstruction total variation

来源：评论

学校读者我要写书评

暂无评论

A Variational Inequality Model for Learning Neural Networks 48

A Variational Inequality Model for Learning Neural Networks

引用

48th IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP 2023

作者： Combettes, Patrick L. Pesquet, Jean-Christophe Repetti, Audrey North Carolina State University Department of Mathematics Raleigh United States Unversité Paris-Saclay Centre de Vision Numérique CentraleSupélec Inria Gif sur Yvette France Heriot-Watt University Maxwell Inst. for Mathematical Sciences Inst. of Sensors Signals and Systems Edinburgh United Kingdom

ISBN: (纸本)9781728163277

Neural networks have become ubiquitous tools for solving signal and image processing problems, and they often outperform standard approaches. Nevertheless, training the layers of a neural network is a challenging task in many applications. The prevalent training procedure consists of minimizing highly non-convex objectives based on data sets of huge dimension. In this context, current methodologies are not guaranteed to produce global solutions. We present an alternative approach which foregoes the optimization framework and adopts a variational inequality formalism. The associated algorithm guarantees convergence of the iterates to a true solution of the variational inequality and it possesses an efficient block-iterative structure. A numerical application is presented. © 2023 IEEE.

关键词： block-iterative algorithm MRI neural networks transfer learning variational inequality

来源：评论

学校读者我要写书评

暂无评论

Multivariate Monotone Inclusions in Saddle Form

引用

MATHEMATICS OF OPERATIONS RESEARCH 2022年第2期47卷 1082-1109页

作者： Bui, Minh N. Combettes, Patrick L. North Carolina State Univ Dept Math Raleigh NC 27695 USA

We propose a novel approach to monotone operator splitting based on the notion of a saddle operator. Under investigation is a highly structured multivariate monotone inclusion problem involving a mix of set-valued, cocoercive, and Lipschitzian monotone operators, as well as various monotonicity-preserving operations among them. This model encompasses most formulations found in the literature. A limitation of existing primal-dual algorithms is that they operate in a product space that is too small to achieve full splitting of our problem in the sense that each operator is used individually. To circumvent this difficulty, we recast the problem as that of finding a zero of a saddle operator that acts on a bigger space. This leads to an algorithm of unprecedented flexibility, which achieves full splitting, exploits the specific attributes of each operator, is asynchronous, and requires to activate only blocks of operators at each iteration, as opposed to activating all of them. The latter feature is of critical importance in large-scale problems. The weak convergence of the main algorithm is established, aswell as the strong convergence of a variant. Various applications are discussed, and instantiations of the proposed framework in the context of variational inequalities and minimization problems are presented.

关键词： monotone inclusion monotone operator saddle form operator splitting block-iterative algorithm asynchronous algorithm strong convergence

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：