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Linearization for Microwave Photonic OFDM Transmission Systems Using an iterative algorithm Based on FEC Mechanism

JOURNAL OF LIGHTWAVE TECHNOLOGY 2022年第15期40卷 5013-5020页

作者： Chen, Yu Chen, Yang East China Normal Univ Shanghai Key Lab Multidimens Informat Proc Shanghai 200241 Peoples R China East China Normal Univ Engn Ctr SHMEC Space Informat & GNSS Shanghai 200241 Peoples R China

A digital linearization algorithm is proposed to reduce the third-order intermodulation distortion (IMD3) for the microwave photonic (MWP) orthogonal frequency-division multiplexing (OFDM) transmission system with intensity modulation and direct detection. Forward error correction (FEC) is added to the OFDM signal to suppress the IMD3 in conjunction with an iterative operation. The distorted OFDM signal from the MWP system goes through iterative operations including fast Fourier transform, demodulation, error correction, signal reconstruction, and interference cancellation until the output converges. Compared with the non-iterative method and the iterative method without FEC mechanism, the proposed method has a significant advantage in linearizing signals with large nonlinearity and low signal-to-noise ratio. 200-Msym/s 64 quadrature-amplitude modulation (64-QAM) OFDM signals with a large peak-to-peak voltage of 650 mV are amplified by a power amplifier and then input to the MWP link and linearized by the FEC-based iterative method. The results show that the error vector magnitudes (EVMs) of the OFDM signals can be optimized from 13.1% to 2.9% and from 13.4% to 6.3% when the output E-b/N-0 from the MWP link is about 35 dB and 13.5 dB, respectively. Besides, a 3-GHz 64-QAM OFDM signal is successfully transmitted through a 25-km standard single-mode fiber with an EVM of 3.9% after linearization.

关键词： OFDM iterative methods Interference Forward error correction Optical distortion Signal to noise ratio Codes Digital signal processing forward error correction iterative algorithm linearization third-order intermodulation distortion

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Metasurfaces designed by a bidirectional deep neural network and iterative algorithm for generating quantitative field distributions

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Light(Advanced Manufacturing) 2023年第2期4卷 28-38页

作者： Yang Zhu Xiaofei Zang Haoxiang Chi Yiwen Zhou Yiming Zhu Songlin Zhuang Terahertz Technology Innovation Research Institute and Shanghai Key Lab of Modern Optical SystemUniversity of Shanghai for Science and TechnologyNo.516 JunGong RoadShanghai200093China

Metasurfaces,which are the two-dimensional counterparts of metamaterials,have demonstrated unprecedented capabilities to manipulate the wavefront of electromagnetic waves in a single flat *** various advances in this field,the unique functionalities achieved by metasurfaces have come at the cost of the structural complexity,resulting in a time-consuming parameter sweep for the conventional metasurface *** artificial neural networks provide a flexible platform for significantly improving the design process,the current metasurface designs are restricted to generating qualitative field *** this study,we demonstrate that by combining a tandem neural network and an iterative algorithm,the previous restriction of the design of metasurfaces can be overcome with quantitative field *** proof-of-principle examples,metalenses predicted via the designed network architecture that possess multiple focal points with identical/orthogonal polarisation states,as well as accurate intensity ratios(quantitative field distributions),were numerically calculated and experimentally *** unique and robust approach for the metasurface design will enable the acceleration of the development of devices with high-accuracy functionalities,which can be applied in imaging,detecting,and sensing.

关键词： Metasurfaces Bidirectional deep neural network iterative algorithm Focal points Vortex

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On iterative algorithm and Perturbation Analysis for the Nonlinear Matrix Equation

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Communications on Applied Mathematics and Computation 2022年第3期4卷 1158-1174页

作者： Chacha Stephen Chacha Department of Mathematics Physics and InformaticsMkwawa University College of EducationP.O.Box 2513IringaTanzania

In this study,an iterative algorithm is proposed to solve the nonlinear matrix equation X+A∗eXA=*** expressions for mixed and componentwise condition numbers with their upper bounds are derived to measure the sensitivity of the considered nonlinear matrix *** analysis for the derived condition numbers and the proposed algorithm are *** proposed iterative algorithm reduces the number of iterations significantly when incorporated with exact line *** condition number seems more reliable to detect the sensitivity of the considered equation than mixed condition number as validated by numerical examples.

关键词： Mixed condition number Componentwise condition number iterative algorithm Perturbation analysis Exact line search

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Optimal tracking control for stochastic discrete-time systems based on improved Riccati iterative algorithm 41

Optimal tracking control for stochastic discrete-time system...

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第41届中国控制会议

作者： Shuangyun Xing Yifan Liu School of Science Shenyang Jianzhu University School of Electrical and Control Engineering Shenyang Jianzhu University

ISBN: (数字)9789887581536

ISBN: (纸本)9781665482561

In this paper,an improved stochastic algebraic Riccati(SAR) iterative algorithm based on numerical iterative is adopted to solve the stochastic linear quadratic optimal tracking(SLQT) control problem for stochastic discrete-time ***,an augmented system composed of the stochastic discrete-time system and command generator is ***,the augmented stochastic algebraic Riccati equation(SARE) is derived based on the augmented system and the corresponding SAR iterative algorithm is obtained according to the idea of value iteration(VI) ***,an improved SAR iterative algorithm is raised based on the given SAR iterative algorithm and combined with the numerical iterative ***,simulation results verify the effectiveness of the proposed algorithm.

关键词： Stochastic discrete-time systems Optimal tracking control iterative algorithm

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An iterative algorithm for discrete Lyapunov matrix equations

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IET CONTROL THEORY AND APPLICATIONS 2021年第16期15卷 2027-2038页

作者： Wu, Ai-Guo Zhang, Ying Sun, Hui-Jie Duan, Hua-Jie Harbin Inst Technol Sch Mech Engn & Automat Shenzhen Peoples R China Sun Yat Sen Univ Sch Aeronaut & Astronaut Guangzhou Peoples R China

In this paper, an iterative algorithm is established to solve discrete Lyapunov matrix equations. In this algorithm, a tuning parameter is introduced such that the iterative solution can be updated by using a combination of the information in the last step and the previous step. Some conditions for the convergence of the proposed algorithm are given. In addition, an approach is also developed to choose the optimal tuning parameter such that the algorithm achieves its fastest convergence rate. A numerical example is employed to illustrate the effectiveness of the proposed algorithm.

关键词： convergence rate iterative algorithm discrete Lyapunov matrix equations Linear algebra (numerical analysis) convergence of numerical methods iterative methods Numerical analysis Interpolation and function approximation (numerical analysis) optimal tuning parameter Lyapunov matrix equations Numerical approximation and analysis

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Extending the applicability and convergence domain of a higher-order iterative algorithm under ω condition

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RENDICONTI DEL CIRCOLO MATEMATICO DI PALERMO 2022年第1期71卷 469-482页

作者： Argyros, Ioannis K. Sharma, Debasis Argyros, Christopher I. Parhi, Sanjaya Kumar Sunanda, Shanta Kumari Cameron Univ Dept Math Sci Lawton OK 73505 USA IIIT Bhubaneswar Dept Math Bhubaneswar 751003 Odisha India Univ Oklahoma Dept Comp Sci Norman OK 73071 USA Fakir Mohan Univ Dept Math Balasore 756020 Odisha India

The main contribution of this study is that the applicability and convergence domain of a fifth-order convergent equation solver is extended. We use omega condition on the first Frechet derivative to study the local analysis, and this expands the applicability of the formula for such problems where the earlier study based on Lipschitz constants cannot be used. Also, we avoid the use of the extra assumption on boundedness of the first derivative of the nonlinear operator. Our idea can be used on other iterative methods. Numerical tests confirmed that the proposed analysis produces a larger convergence domain, in comparison to the earlier study, without using additional conditions.

关键词： Local convergence iterative algorithm Banach space omega continuity condition

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An iterative algorithm for generalized periodic multiple coupled Sylvester matrix equations

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JOURNAL OF THE FRANKLIN INSTITUTE 2021年第10期358卷 5513-5531页

作者： Chen, Xuesong Chen, Zebin Guangdong Univ Technol Sch Appl Math Guangzhou 510006 Peoples R China

The paper is indicated to constructing a modified conjugate gradient iterative (MCG) algorithm to solve the generalized periodic multiple coupled Sylvester matrix equations. It can be proved that the proposed approach can find the solution within finite iteration steps in the absence of round-off errors. Furthermore, we provide a method for choosing the initial matrices to obtain the least Frobenius norm solution of the system. Some numerical examples are illustrated to show the performance of the proposed approach and its superiority over the existing method CG. (C) 2021 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

关键词： Sylvester matrix equation Conjugate gradient iterative algorithm Least Frobenius norm solution

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iterative algorithm and theoretical treatment of existence of solution for (k, z)-Riemann-Liouville fractional integral equations

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JOURNAL OF PSEUDO-DIFFERENTIAL OPERATORS AND APPLICATIONS 2022年第3期13卷 39-39页

作者： Das, Anupam Rabbani, Mohsen Mohiuddine, S. A. Deuri, Bhuban Chandra Cotton Univ Dept Math Gauhati 781001 Assam India Islamic Azad Univ Dept Math Sari Branch Sari Iran King Abdulaziz Univ Fac Appl Studies Dept Gen Required Courses Math Jeddah 21589 Saudi Arabia King Abdulaziz Univ Dept Math Operator Theory & Applicat Res Grp Fac Sci Jeddah 21589 Saudi Arabia Rajiv Gandhi Univ Dept Math Rono Hills Doimukh 791112 Arunachal Prade India

In our discussion, existence of solution for fractional integral equation (FIE) involving (k, z)-Riemann-Liouville fractional integral is studied. To achieve this goal, first using shifting distance functions, we establish a new generalization of Dorbo-type fixed point theorem, in short, we shall write DFPT, and then we apply our DFPT on aforementioned FIE to establish the existence result. Also, our results will be verified by considering a suitable example. Moreover, an approximate solution of the example is given via a convergent iterative algorithm constructed by modified homotopy perturbation (MHP) method with a high accuracy.

关键词： Darbo-type theorem Measure of noncompactness (MNC) Continuous function Fractional integral equation Banach space iterative algorithm Modified homotopy perturbation

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An iterative algorithm to improve infrared thermographic systems? accuracy in temperature field measurement of aluminum alloys

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MEASUREMENT 2023年第1期210卷

作者： Zhang, Kaiyue Liu, Bin Lei, Yu Guo, Liang Fu, Ruidong Zhang, Yucun Zhang, Yungang Yanshan Univ Coll Elect Engn Qinhuangdao 066004 Peoples R China Yanshan Univ Coll Mat Sci & Engn State Key Lab Metastable Mat Sci & Technol Qinhuangdao 066004 Peoples R China

Accurate real-time measurement of temperature is vital for ensuring successful production of aluminum alloy parts. As an excellent approach to real-time measurement of aluminum alloys' temperature field, infrared thermal imaging systems enable non-contact, fast-response measurement. However, the emissivity of aluminum alloys varies by temperature, making accurate measurements by infrared thermographic systems unavailable. For this reason, an emissivity iterative algorithm is proposed in this paper. The emissivity-temperature curves of aluminum alloys are obtained and used for the correction of the temperature field. The algorithm helps infrared thermal imaging systems reduce their dependency on emissivity and thus realizes a precise temperature field measurement for aluminum alloy. To validate this model, we conduct experiments to measure the temperature field of uniformly heated aluminum alloys, and of friction stir welding. Results of the experiments show this model can effectively improve the accuracy of infrared thermographic systems for measuring the temperature field of aluminum alloys.

关键词： Aluminum alloys Infrared thermography Emissivity iterative algorithm Temperature field measurement

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A New iterative algorithm for the Multiple-Sets Split Feasibility Problem and the Split Equality Fixed Point Problem

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MEDITERRANEAN JOURNAL OF MATHEMATICS 2021年第1期18卷 1-24页

作者： Guan, Jin-Lin Chongqing Technol & Business Univ Coll Math & Stat Chongqing 400067 Peoples R China

In this paper, we propose a new iterative algorithm for solving the multiple-sets split feasibility problem and the split equality fixed point problem of firmly quasi-nonexpansive mappings in real Hilbert spaces. Under very mild conditions, we prove a weak convergence theorem for our algorithm using projection method and the properties of firmly quasi-nonexpansive mappings. Our result improves and extends the corresponding ones announced by some others in the earlier and recent literature.

关键词： Multiple-sets split feasibility problem split equality fixed point problem weak convergence iterative algorithm Hilbert spaces

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