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Graph convergence for the H(.,.)-mixed mapping with an application for solving the system of generalized variational inclusions

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Fixed Point Theory and Applications 2013年第1期2013卷 1-21页

作者： Husain, Shamshad Gupta, Sanjeev Mishra, Vishnu Narayan Department of Applied Mathematics Faculty of Engineering and Technology Aligarh Muslim University Aligarh 202002 India Department of Applied Mathematics and Humanities Sardar Vallabhbhai National Institute of Technology Surat 395 007 India

In this paper, we investigate a class of accretive mappings called the H(., .)-mixed mappings in Banach spaces. We prove that the proximal-point mapping associated with the H(., .)-mixed mapping is single-valued and Lipschitz continuous. Some examples are given to justify the definition of H(., .)-mixed mapping. Further, a concept of graph convergence concerned with the H(., .)-mixed mapping is introduced in Banach spaces and some equivalence theorems between graph-convergence and proximal-point mapping convergence for the H(., .)-mixed mappings sequence are proved. As an application, we consider a system of generalized variational inclusions involving H(., .)-mixed mappings in real q-uniformly smooth Banach spaces. Using the proximal-point mapping method, we prove the existence and uniqueness of solution and suggest an iterative algorithm for the system of generalized variational inclusions. Furthermore, we discuss the convergence criteria for the iterative algorithm under some suitable conditions. © 2013 Husain et al.;licensee Springer.

关键词： Graph convergence H(., .)-mixed mapping iterative algorithm Proximal-point mapping method System of generalized variational inclusions

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Solvability and iterative algorithms for a system of generalized nonlinear mixed quasivariational inclusions with (H_i, η_i)-monotone operators

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JOURNAL OF INEQUALITIES AND APPLICATIONS 2012年第1期2012卷 1-13页

作者： Liu, Zeqing Wang, Lili Ume, Jeong Sheok Kang, Shin Min Liaoning Normal Univ Dept Math Dalian 116029 Liaoning Peoples R China Changwon Natl Univ Dept Math Chang Won 641773 South Korea Gyeongsang Natl Univ Dept Math Chinju 660701 South Korea Gyeongsang Natl Univ RINS Chinju 660701 South Korea

In this paper, we introduce and discuss a new system of generalized nonlinear mixed quasivariational inclusions with -monotone operators in Hilbert spaces, which includes several systems of variational inequalities and variational inclusions as special cases. By employing the resolvent operator technique associated with -monotone operators, we suggest two iterative algorithms for computing the approximate solutions of the system of generalized nonlinear mixed quasivariational inclusions. Under certain conditions, we obtain the existence of solutions for the system of generalized nonlinear mixed quasivariational inclusions and prove the convergence of the iterative sequences generated by the iterative algorithms. The results presented in this paper extend, improve and unify many known results in recent literature.

关键词： (H-i, eta(i))-monotone operators resolvent operator technique iterative algorithm Mann perturbed iterative algorithm with mixed errors set-valued mapping convergence system of generalized nonlinear mixed quasivariational inclusions Hilbert space

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The Reconstruction Research of 3D Temperature Field of Flame of the Optical Fiber Taper Machine Based on the Multispectral Radiation

The Reconstruction Research of 3D Temperature Field of Flame...

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2nd International Conference on Measurement, Information and Control (ICMIC)

作者： Zhang Zhilin Sun Weimin Xing Jian Cui Shuanglong Harbin Engn Univ Harbin 150001 Peoples R China

ISBN: (纸本)9781479913909

A novel iterative reconstruction algorithm is proposed in this paper. The experiment of the optical fiber taper machine flame has been carried on, and the measurements on the front and profile of flame of the optical fiber tapering machine have been conducted at different heights. The reconstructions of 3D surface diagram and isotherm diagram of the flame have been processed by using SIRT-TVM-DART joint reconstruction algorithm. At last the uncertainty is analyzed.

关键词： multispectral thermometry 3D temperature field iterative algorithm

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An uplink power control algorithm using traditional iterative model for cognitive radio networks

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Journal of Central South University 2012年第10期19卷 2816-2822页

作者：李枫谭学治王丽 School of Electronics Information Engineering Harbin Institute of Technology Department of Automation Measurement and Control Harbin Institute of Technology

Based on the analysis of the feature of cognitive radio networks, a relevant interference model was built. Cognitive users should consider especially the problem of interference with licensed users and satisfy the signal-to-interference noise ratio （SINR） requirement at the same time. According to different power thresholds, an approach was given to solve the problem of coexistence between licensed user and cognitive user in cognitive system. Then, an uplink distributed power control algorithm based on traditional iterative model was proposed. Convergence analysis of the algorithm in case of feasible systems was provided. Simulations show that this method can provide substantial power savings as compared with the power balancing algorithm while reducing the achieved SINR only slightly, since 6% S1NR loss can bring 23% power gain. Through further simulations, it can be concluded that the proposed solution has better effect as the noise power or system load increases.

关键词： cognitive radio uplink power control interference iterative algorithm

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Two Novel iterative algorithms for Interference Alignment with Symbol Extensions in the MIMO Interference Channel

Two Novel Iterative Algorithms for Interference Alignment wi...

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4th International Conference on Wireless Communications and Signal Processing (WCSP)

作者： Wang, Chao Deng, Ke Li, Yubo Xi An Jiao Tong Univ Sch Elect & Informat Engn Xian 710049 Peoples R China

ISBN: (纸本)9781467358293;9781467358309

Interference alignment(IA) with symbol extensions in the K-user multiple-input multiple-output (MIMO) interference channel(IC) is considered in this paper. Symbol extensions produce the channels of special structure. Most of existing approaches are limited in cases where the channels have some special structure, because they align the interference without preserving the dimensionality of the desired signal. For that reason, two novel iterative algorithms for IA with symbol extensions are proposed. The first algorithm designs transceivers for IA based on minimizing the maximum per-user mean square error(MSE) while preserving the dimensionality of the desired signal. Utilizing channel reciprocity, the second algorithm is proposed which is the constrained optimization problem. It maximizes each receiver's SINR while preserving the dimensionality of the desired signal. The simulation results show that the proposed algorithms not only achieve good performance in terms of BER performance but also achieve good performance on maximizing sum rate of the system.

关键词： IA Interference alignment symbol extensions MIMO interference channel iterative algorithm mean square error

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Radiation dose reduction in medical x-ray CT via Fourier-based iterative reconstruction

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MEDICAL PHYSICS 2013年第3期40卷 031914-031914页

作者： Fahimian, Benjamin P. Zhao, Yunzhe Huang, Zhifeng Fung, Russell Mao, Yu Zhu, Chun Khatonabadi, Maryam DeMarco, John J. Osher, Stanley J. McNitt-Gray, Michael F. Miao, Jianwei Stanford Univ Dept Radiat Oncol Stanford CA 94305 USA Univ Calif Los Angeles Dept Phys & Astron Los Angeles CA 90095 USA Univ Calif Los Angeles Calif NanoSyst Inst Los Angeles CA 90095 USA Univ Minnesota Inst Math & Its Applicat Mineapolis MN 55455 USA Univ Calif Los Angeles David Geffen Sch Med Biomed Phys Interdept Program Los Angeles CA 90095 USA Univ Calif Los Angeles Dept Math Los Angeles CA 90095 USA

Purpose: A Fourier-based iterative reconstruction technique, termed Equally Sloped Tomography (EST), is developed in conjunction with advanced mathematical regularization to investigate radiation dose reduction in x-ray CT. The method is experimentally implemented on fan-beam CT and evaluated as a function of imaging dose on a series of image quality phantoms and anonymous pediatric patient data sets. Numerical simulation experiments are also performed to explore the extension of EST to helical cone-beam geometry. Methods: EST is a Fourier based iterative algorithm, which iterates back and forth between real and Fourier space utilizing the algebraically exact pseudopolar fast Fourier transform (PPFFT). In each iteration, physical constraints and mathematical regularization are applied in real space, while the measured data are enforced in Fourier space. The algorithm is automatically terminated when a proposed termination criterion is met. Experimentally, fan-beam projections were acquired by the Siemens z-flying focal spot technology, and subsequently interleaved and rebinned to a pseudopolar grid. Image quality phantoms were scanned at systematically varied mAs settings, reconstructed by EST and conventional reconstruction methods such as filtered back projection (FBP), and quantified using metrics including resolution, signal-to-noise ratios (SNRs), and contrast-to-noise ratios (CNRs). Pediatric data sets were reconstructed at their original acquisition settings and additionally simulated to lower dose settings for comparison and evaluation of the potential for radiation dose reduction. Numerical experiments were conducted to quantify EST and other iterative methods in terms of image quality and computation time. The extension of EST to helical cone-beam CT was implemented by using the advanced single-slice rebinning (ASSR) method. Results: Based on the phantom and pediatric patient fan-beam CT data, it is demonstrated that EST reconstructions with the lowest sca

关键词： Equally Sloped Tomography (EST) medical x-ray CT radiation dose reduction iterative algorithm pseudopolar fast Fourier transform (PPFFT)

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KACZMARZ algorithm AND FRAMES

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INTERNATIONAL JOURNAL OF WAVELETS MULTIRESOLUTION AND INFORMATION PROCESSING 2013年第5期11卷 1350036-1350036页

作者： Czaja, Wojciech Tanis, James H. Univ Maryland Dept Math College Pk MD 20742 USA Rice Univ Dept Math Houston TX 77251 USA

Sequences of unit vectors for which the Kaczmarz algorithm always converges in Hilbert space can be characterized in frame theory by tight frames with constant 1. We generalize this result to the context of frames and bases. In particular, we show that the only effective sequences which are Riesz bases are orthonormal bases. Moreover, we consider the infinite system of linear algebraic equations Ax = b and characterize the (bounded) matrices A for which the Kaczmarz algorithm always converges to a solution.

关键词： Kaczmarz algorithm frame theory iterative algorithm

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CT Image Reconstruction Based on GPUs

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Procedia Computer Science 2013年 18卷 1412-1420页

作者： Liubov A. Flores Vicent Vidal Patricia Mayo Francisco Rodenas Gumersindo Verdú Polytechnic University of Valencia Camino de Vera s/n 46022 Valencia Spain

In X-ray computed tomography (CT) iterative methods are more suitable for the reconstruction of images with high contrast and precision in noisy conditions and from a small number of projections. However, in practice, these methods are not widely used due to the high computational cost of their implementation. Nowadays technology provides the possibility to reduce effectively this drawback. It is the goal of this work to develop a fast GPU-based algorithm to reconstruct high quality images from under sampled and noisy projection data.

关键词： CT image reconstruction iterative algorithm CUDA C CUBLAS CUSPARSE

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Multi-Sector Joint Beamforming for Pilot Coverage Optimization

Multi-Sector Joint Beamforming for Pilot Coverage Optimizati...

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International Conference on Wireless Communications and Signal Processing (WCSP)

作者： Fan, Dongdong Wu, Zhouyun Huang, Aiping Shan, Hangguan Zhuang, Hongcheng Zhejiang Univ Inst Informat & Commun Engn Hangzhou 310027 Zhejiang Peoples R China China Telecom Technol Innovat Ctr Beijing 100031 Peoples R China Zhejiang Provincial Key Lab Informat Network Tech Hangzhou 310027 Zhejiang Peoples R China Huawei Technol Co Ltd Shenzhen 518129 Peoples R China

ISBN: (纸本)9781479903085

Coverage optimization is an important task which directly affects the performance of cellular networks. The signal-to-interference and noise ratio (SINR) is a key metrics for evaluating coverage effect and its ability of resisting radio propagation condition variation. It is difficult to improve the ability of the pilot coverage of multiple sectors to resist environment variation simultaneously by using the existing methods. In this paper, a novel coverage optimization method based on multi-sector joint beamforming is proposed to maximize the minimum SINR of the sectors. An iterative algorithm is then developed to obtain antenna array excitation weights. Simulation results show that the performance of our algorithm is superior to that of the existing algorithm.

关键词： coverage optimization joint beamforming max min SINR iterative algorithm

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Randomized Kaczmarz algorithm for CT reconstruction

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Journal of Measurement Science and Instrumentation 2013年第1期4卷 34-37页

作者：赵可潘晋孝孔慧华 School of Science North University of China

The order of the projection in the algebraic reconstruction technique(ART)method has great influence on the rate of the *** many scholars have studied the order of the projection,few theoretical proofs are *** Strohmer and Roman Vershynin introduced a randomized version of the Kaczmarz method for consistent,and over-determined linear systems and proved whose rate does not depend on the number of equations in the systems in *** this paper,we apply this method to computed tomography(CT)image reconstruction and compared images generated by the sequential Kaczmarz method and the randomized Kaczmarz *** demonstrates the feasibility of the randomized Kaczmarz algorithm in CT image reconstruction and its exponential curve convergence.

关键词： Kaczmarz method iterative algorithm randomized Kaczmarz method computed tomography(CT) CT image reconstruction exponent curve fitting

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