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Nonlinear multigrid method for solving the anisotropic image denoising models

NUMERICAL algorithmS 2013年第2期63卷 291-315页

作者： Zhang, Jun Yang, Yu-Fei Hunan Univ Coll Math & Econometr Changsha 410082 Hunan Peoples R China Changsha Univ Dept Informat & Comp Sci Changsha 410003 Hunan Peoples R China

In this paper, we study a nonlinear multigrid method for solving a general image denoising model with two L (1)-regularization terms. Different from the previous studies, we give a simpler derivation of the dual formulation of the general model by augmented Lagrangian method. In order to improve the convergence rate of the proposed multigrid method, an improved dual iteration is proposed as its smoother. Furthermore, we apply the proposed method to the anisotropic ROF model and the anisotropic LLT model. We also give the local Fourier analysis (LFAs) of the Chambolle's dual iterations and a modified smoother for solving these two models, respectively. Numerical results illustrate the efficiency of the proposed method and indicate that such a multigrid method is more suitable to deal with large-sized images.

关键词： Image denoising dual algorithm Anisotropic ROF model Anisotropic LLT model Local Fourier analysis Nonlinear multigrid method

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AFFINE-SCALING FOR LINEAR-PROGRAMS WITH FREE VARIABLES

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MATHEMATICAL PROGRAMMING 1989年第1期43卷 31-44页

作者： VANDERBEI, RJ AT & T Bell Laboratories USA

The affine-scaling modification of Karmarkar's algorithm is extended to solve problems with free variables. This extended primal algorithm is used to prove two important results. First the geometrically elegant feasibility algorithm proposed by Chandru and Kochar is the same algorithm as the one obtained by appending a single column of residuals to the constraint matrix. Second the dual algorithm as first described by Adler et al., is the same as the extended primal algorithm applied to the dual.

关键词： Affine-scaling dual algorithm feasibility algorithm Karmarkar's algorithm

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Fuzzy geometric programming (I)

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Fuzzy Sets and Systems 1993年第2期53卷 135-135页

作者： Cao, Bing-yuan Department of Mathematics Changsha Normal University of Water Resources and Electric Power Hunan 410077 China

First, the concepts of fuzzy valuation convex (or concave) function and fuzzy convex-geometric-programming problem are based on a fuzzy valuation set in this paper. Secondly, fuzzy posynomial geometric programming and its dual-form properties concerned are discussed by means of a fuzzy geometric inequality and of a fuzzy dual theory. Lastly, direct and dual algorithms of fuzzy posynomial geometric programming are respectively deduced by the aid of a fuzzy fixed-point theorem and the notion of α, β-cut.

关键词： Fuzzy-valuation sets fuzzy convex (or concave) function fuzzy geometric inequality fuzzy posynomial geometric programming and its dual form direct algorithm dual algorithm

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A dual Model for Restoring Images Corrupted by Mixture of Additive and Multiplicative Noise

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IEEE ACCESS 2021年 9卷 168869-168888页

作者： Zhao, Cuicui Liu, Jun Zhang, Jie Beijing Normal Univ Sch Math Sci Lab Math & Complex Syst Minist Educ China Beijing 100875 Peoples R China Univ Southampton Elect & Comp Sci Southampton SO17 1BJ Hants England

A critical challenge in image restoration is the presence of various types of noise. Meanwhile, noise detection is a crucial step in mixed noise removal. This paper tackles the challenge of restoring images corrupted by a mixture of additive Gaussian and multiplicative Gamma noise. In the proposed method, we integrate the noise detection process into a variational model using a dual formulation of a maximum a posteriori (MAP) estimator. The variational model consists of a novel adaptive fidelity term and a plugin-and-play regularization term. The fidelity term contains an adaptive weight that can automatically detect the noise types, levels, and pollution ways for each pixel. There is flexibility in choosing a plugin-and-play regularization term. For example, we can use a model-based regularizer or a deep learning-based regularizer. In addition, we present a splitting algorithm to minimize the proposed cost functional. This splitting technique enables us to transfer a mixed noise removing problem to several subproblems, including noise removal and detection. The noise detection process can be iteratively estimated by the proposed algorithm itself. Therefore, in the numerical experiments, the proposed model outperforms the existing Rudin-Osher-Fatemi (ROF), Aubert-Aujol (AA), BM3D, and deep learning-based single type denoiser. Experimental results show that the proposed model can remove noise more efficiently and better preserve details in images. Compared to the existing best-performing single type denoiser, on average, the improvements of PSNR values range from 0.33 dB to 0.81 dB under noise mixture ratios alpha = 0.4, 0.6.

关键词： Image denoising mixed noise regularization deep learning dual algorithm

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Modelling incentives for collaboration in mobile ad hoc networks

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PERFORMANCE EVALUATION 2004年第4期57卷 427-439页

作者： Crowcroft, J Gibbens, R Kelly, F Östring, S Univ Cambridge Comp Lab Cambridge CB2 3QG England Univ Cambridge Stat Lab Cambridge CB2 1SB England

This paper explores a model for the operation of an ad hoc mobile network. The model incorporates incentives for users to act as transit nodes on multi-hop paths and to be rewarded with their own ability to send traffic. The paper explores consequences of the model by means of fluid-level simulations of a network and illustrates the way in which network resources are allocated to users according to their geographical position. (C) 2004 Elsevier B.V. All rights reserved.

关键词： ad hoc mobile networks fluid-level simulations dual algorithm incentives

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Modelling incentives for collaboration in mobile ad hoc networks

Modelling incentives for collaboration in mobile ad hoc netw...

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1st Workshop in Modeling and Optimization of Mobile, Ad Hoc and Wireless Networks (WiOpt 03)

作者： Crowcroft, J Gibbens, R Kelly, F Östring, S Univ Cambridge Comp Lab Cambridge CB2 3QG England Univ Cambridge Stat Lab Cambridge CB2 1SB England

关键词： ad hoc mobile networks fluid-level simulations dual algorithm incentives

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A Hierarchical Matrix Inversion algorithm for Vectorless Power Grid Verification

A Hierarchical Matrix Inversion Algorithm for Vectorless Pow...

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IEEE and ACM International Conference on Computer-Aided Design

作者： Xiong, Xuanxing Wang, Jia IIT Dept Elect & Comp Engn Chicago IL 60616 USA

ISBN: (纸本)9781424481927

Vectorless power grid verification is a powerful technique to validate the robustness of the on-chip power distribution network for all possible current waveforms. Formulated and solved as linear programming problems, vectorless power grid verification demands intensive computational power due to the large number of nodes in modern power grids. Previous work showed that the performance bottleneck of this powerful technique is within the sub-problem of power grid analysis, which essentially computes the inverse of the sparse but large power grid matrix. In this paper, we propose a hierarchical matrix inversion algorithm to compute the rows of the inverse efficiently by exploiting the structure of the power grid. The proposed algorithm is integrated with a previous dual algorithm addressing an orthogonal sub-problem for vectorless power grid verification. Results show that the proposed hierarchical algorithm accelerates the matrix inversion significantly, and thus makes the overall vectorless power grid verification efficient.

关键词： current waveforms dual algorithm hierarchical matrix inversion algorithm integrated circuit design linear programming linear programming problems on-chip power distribution network orthogonal sub-problem power grid analysis power grid matrix power grids power supply circuits vectorless power grid verification

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Joint Power Allocation for DF MIMO Relay Links with Hybrid Power Constraints

Joint Power Allocation for DF MIMO Relay Links with Hybrid P...

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8th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM)

作者： Lu, Feng Liu, Chen Fu, Youhua Zhao, Hua-An Southeast Univ Sch Informat Sci & Engn Nanjing 210096 Jiangsu Peoples R China Nanjing Univ Posts & Telecommunicat Sch Elect Sci & Engn Nanjing Peoples R China Kumamoto Univ Dept Comp Sci & Elect Engn Kumamoto 8608555 Japan

ISBN: (纸本)9781612846835;9781612846828

This paper deals with joint power allocation (PA) for decode-and-forward (DF) two-hop MIMO relay links with hybrid power constraints. In order to maximize the instantaneous information rate of each hop, we propose an optimal PA scheme via a primal-dual algorithm. Then, we jointly allocate the power between the source and the relay to improve the power efficiency further. The simulations will validate the proposed scheme and show that, compared with the traditional uniform PA, our scheme outperforms the counterpart.

关键词： relay decode-and-forward power allocation hybrid power constraints dual algorithm

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Controlling the Internet: A survey and some new results

Controlling the Internet: A survey and some new results

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42nd IEEE Conference on Decision and Control

作者： Liu, S Basar, T Srikant, R Univ Illinois Dept Elect & Comp Engn Urbana IL 61801 USA

ISBN: (纸本)0780379241

In the last few years, significant progress has been made in the mathematical modelling of congestion control and congestion feedback mechanisms in the Internet. The resulting models have proved to be very useful in improving existing control and feedback mechanisms, and to make them scalable to networks that operate at very high speeds. Tools from convex optimization, control theory and stochastic processes have played a major role in the development of this Internet congestion control theory. In this paper, we focus on the control-theoretic aspects of the theory, and review some recent developments in the design of stable, scalable congestion control mechanisms. We also present a new scheme that can improve the performance of the Internet with minimal changes to the current architecture.

关键词： AQM AVQ Congestion Control dual algorithm Generalized Nyquist Criterion Primal algorithm Primal-dual algorithm RED TCP

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Ibm :: 1620 :: General Program Library :: 10.1.002 Linear Programming Code for the Ibm 1620 with Card Input and Output

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2016年

Ibm :: 1620 :: General Program Library :: 10.1.002 Linear Programming Code for the Ibm 1620 with Card Input and Output by published by

关键词： algorithm changer console switch cost changer data depress depress release dual algorithm entered fixed point floating point general input library linear matrix output program record mark rhs changer set shadow price simplex algorithm

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