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Approximation of Common Fixed Point o Two Quasi-nonexpansive Mappings in Convex Metric Spaces

MEDITERRANEAN JOURNAL OF MATHEMATICS 2018年第3期15卷 77-77页

作者： Fukhar-ud-din, H. Khan, A. R. King Fahd Univ Petr & Minerals Dept Math & Stat Dhahran 31261 Saudi Arabia Islamia Univ Bahawalpur Dept Math Bahawalpur 63100 Pakistan

We use a simple iterative algorithm for two quasi-nonexpansive mappings to approximate their common fixed point through Delta-convergence and strong convergence of the algorithm. Our results are new in the literature ... 详细信息

关键词： Convex metric space quasi-nonexpansive mapping jointly demiclosed principle common fixed point iterative algorithm convergence

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Nonlinear Luenberger observer design via invariant manifold computation

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IFAC Proceedings Volumes 2014年第3期47卷 37-42页

作者： Noboru Sakamoto Branislav Rehák Kouji Ueno N. Sakamoto is with Department of Aerospace Engineering Graduate School of Engineering Nagoya University Furo-cho Chikusa-ku Nagoya Japan B. Rehák is with the Institute of Information theory and Automation of the AS CR Pod vodarenskou vezi 4 182 08 Praha 8 Czech Republic K. Ueno is with Department of Aerospace Engineering Graduate School of Engineering Nagoya University Furo-cho Chikusa-ku Nagoya Japan

A framework to extend Luenberger observer to nonlinear systems is proposed. The theory of invariant manifolds plays a central role in the framework. It is shown that the invariant manifolds for observer design are often non-standard ones and this makes their computations challenging. The proposed theory successfully removes the condition imposed on the system to be observed in the previous research in nonlinear Luenberger observer. Numerical examples show that the design methods proposed produce more effective observers compared with linear observers.

关键词： Nonlinear observer invariant manifold iterative algorithm

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An iterative procedure to solve HJBI equations in nonlinear H ∞ control

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IFAC Proceedings Volumes 2008年第2期41卷 200-205页

作者： Yantao Feng Michael Rotkowitz Brian D.O. Anderson Department of Information Engineering Research School of Information Sciences and Engineering the Australian National University Canberra ACT 0200 Australia National ICT Australia 7 London Circuit Canberra ACT 0200 Australia Department of Electrical and Electronic Engineering The University of Melbourne Parkville VIC 3010 Australia

In this paper, an iterative algorithm to solve a special class of Hamilton-Jacobi-Bellman-Isaacs (HJBI) equations is proposed. By constructing two series of nonnegative functions, we replace the problem of solving an HJBI equation by the problem of solving a sequence of Hamilton-Jacobi-Bellman (HJB) equations whose solutions can be approximated recursively by existing methods. The local convergence of the algorithm is guaranteed. A numerical example is provided to demonstrate the accuracy of the proposed algorithm.

关键词： HJBI iterative algorithm locally exponentially stable

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Incremental Path Repair in Hierarchical Motion-Planning with Dynamical Feasibility Guarantees for Mobile Robotic Vehicles

Incremental Path Repair in Hierarchical Motion-Planning with...

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European Control Conference (ECC)

作者： Zhang, Zetian Cowlagi, Raghvendra V. Worcester Polytech Inst Aerosp Engn Program Worcester MA 01609 USA

ISBN: (纸本)9783952426937

New requirements of autonomous mobile vehicles necessitate hierarchical motion-planning techniques that not only find a plan to satisfy high-level specifications, but also guarantee that this plan is suitable for execution under vehicle dynamical constraints. In this context, the H-cost motion planning technique has been reported in the recent literature. We propose an incremental motion-planning algorithm based on this technique. The proposed algorithm retains the benefits of the original technique, while significantly reducing the associated computational time. In particular, the proposed iterative algorithm presents during intermediate iterations feasible solutions, with the guarantee that the algorithm eventually converges to an optimal solution. The costs of solutions at intermediate iterations are almost always nonincreasing. Therefore, the proposed algorithm is suitable for real-time implementations, where hard bounds on the available computation time are imposed, and where the original H-cost optimization algorithm may not have sufficient time to converge to a solution at all. We illustrate the proposed algorithm with numerical simulation examples.

关键词： iterative methods mobile robots optimisation path planning H-cost motion-planning technique H-cost optimization algorithm autonomous mobile vehicles dynamical feasibility guarantees hierarchical motion-planning incremental motion-planning algorithm incremental path repair iterative algorithm mobile robotic vehicles vehicle dynamical constraints Atmospheric modeling Cost function History Planning Real-time systems Trajectory Vehicles

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A survey on the algorithm and development of multiple sequence alignment

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BRIEFINGS IN BIOINFORMATICS 2022年第3期23卷 bbac069-bbac069页

作者： Zhang, Yongqing Zhang, Qiang Zhou, Jiliu Zou, Quan Chengdu Univ Informat Technol Sch Comp Sci Chengdu Peoples R China Univ Elect Sci & Technol China Inst Fundamental & Frontier Sci Chengdu 610054 Peoples R China

Multiple sequence alignment (MSA) is an essential cornerstone in bioinformatics, which can reveal the potential information in biological sequences, such as function, evolution and structure. MSA is widely used in many bioinformatics scenarios, such as phylogenetic analysis, protein analysis and genomic analysis. However, MSA faces new challenges with the gradual increase in sequence scale and the increasing demand for alignment accuracy. Therefore, developing an efficient and accurate strategy for MSA has become one of the research hotspots in bioinformatics. In this work, we mainly summarize the algorithms for MSA and its applications in bioinformatics. To provide a structured and clear perspective, we systematically introduce MSA's knowledge, including background, database, metric and benchmark. Besides, we list the most common applications of MSA in the field of bioinformatics, including database searching, phylogenetic analysis, genomic analysis, metagenomic analysis and protein analysis. Furthermore, we categorize and analyze classical and state-of-the-art algorithms, divided into progressive alignment, iterative algorithm, heuristics, machine learning and divide-and-conquer. Moreover, we also discuss the challenges and opportunities of MSA in bioinformatics. Our work provides a comprehensive survey of MSA applications and their relevant algorithms. It could bring valuable insights for researchers to contribute their knowledge to MSA and relevant studies.

关键词： multiple sequence alignment progressive alignment iterative algorithm heuristic

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Maximum likelihood estimation of high-dimensional Student-t copulas

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STATISTICS & PROBABILITY LETTERS 2020年第0期159卷 108678-000页

作者： Trede, Mark Westfalische Wilhelms Univ Munster Dept Econ Inst Econometr & Econ Stat Munster Germany

This paper suggests a simple iterative and robust maximum likelihood estimation method for the parameters of a high-dimensional Student t-distribution that is substantially faster than direct maximum likelihood approa... 详细信息

关键词： Student t-copula Maximum likelihood estimation iterative algorithm

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Low sidelobe waveform design with constant modulus constraint for high-frequency radar

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JOURNAL OF ENGINEERING-JOE 2019年第19期2019卷 6085-6089页

作者： Shi, Shengnan Wang, Zhaoyi He, Zishu Cheng, Ziyang Univ Elect Sci & Technol China Dept Informat & Commun Engn Chengdu Sichuan Peoples R China

This article designs waveform in fast-time domain to optimise high-frequency radar performances embedded in the co-channel interference and coloured noise. Considering the whitening filter is applied for fast-time processing, a novel objective function accounting for both signal to interference plus noise ratio (SINR) and integrated range sidelobe level (IRSL) is introduced and the constant modulus constraint is forced on the probing waveform. An iterative algorithm based on the alternating direction method of multipliers is presented, resolving such non-convex quartic optimisation problem with a polynomial-time computational complexity. In each iteration, two quadratic problems are presented, with the closed-form solutions given. Finally, the authors evaluate the effectiveness of the designed waveform in terms of the range-Doppler processing result, SINR, IRSL and power spectrum.

关键词： Doppler radar filtering theory iterative methods radar signal processing computational complexity cochannel interference signal denoising concave programming quadratic programming radar interference nonconvex quartic optimisation problem polynomial-time computational complexity range-Doppler processing result SINR IRSL low sidelobe waveform design constant modulus constraint fast-time domain high-frequency radar performances co-channel interference coloured noise whitening filter fast-time processing integrated range sidelobe level probing waveform iterative algorithm signal to interference plus noise ratio alternating direction method of multipliers quadratic problems

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Improved modeling of leaf stomatal conductance by incorporating its highly dynamic responses to varying light conditions in Mango species (Mangifera indica L.)

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SCIENTIA HORTICULTURAE 2024年 328卷

作者： Zhuang, Jie Wang, Quan Jin, Jia Shizuoka Univ Grad Sch Sci & Technol Shizuoka 4228529 Japan Shizuoka Univ Fac Agr Shizuoka 4228529 Japan Nanning Normal Univ Inst Geog & Oceanog Nanning Peoples R China

Dramatic variations in natural light conditions can cause complex stomatal conductance responses in plant leaves but are often overlooked in current models of stomatal conductance, impeding our understanding of the internal mechanisms governing stomatal conductance (gsw) in plant leaves. Experimentally determined dynamic response patterns of gsw to various light conditions in Mangifera indica L. (Mango). The results also indicated that photosynthetic photon flux density (PPFD), the proportion of blue light (PB), vapor pressure deficit (VPD), and leaf type (Ltype) had significant effects on gsw, resulting in the popular stomatal conductance models (Jarvis, BallWoodrow-Berry (BWB), Ball-Berry-Leuning (BBL), and Unified Stomatal Optimization (USO)) having different degrees of overestimation or underestimation under varying light conditions. We have further integrated the influence of potential variables into the Jarvis, BWB, BBL, and USO models and analyzed their impact on gsw, resulting in an increase of 0.08-0.36 in R2 and 0.032-1.08 in RPD. Among the models, the improved USO model incorporating the constraints from PPFD and Ltype, exhibited the highest performance (R2 = 0.85, RPD = 2.55). Therefore, for accurate estimation of gsw, the model should take into account the light conditions and the difference between sunlit and shaded areas, especially in natural environments where light conditions change frequently.

关键词： Coupled model iterative algorithm Light quality Photosynthesis Stomatal conductance Varying light conditions

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PRECODING AND DECODING DESIGN FOR TWO-WAY MIMO AF MULTIPLE-RELAY SYSTEM

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Journal of Electronics(China) 2012年第Z2期 177-189页

作者： Zhi Hui Yang Longxiang Zhu Hongbo (Jiangsu Key Lab of Wireless Communication, Nanjing University of Posts and Telecommunications, Nanjing 210003, China)

In this paper, a joint precoding and decoding design scheme is proposed for two-way Multiple-Input Multiple-Output (MIMO) multiple-relay system. The precoding and decoding matrices are jointly optimized based on Minimum Mean-Square-Error (MMSE) criteria under transmit power constraints. The optimization problem is solved by using a convergent iterative algorithm which in-cludes four sub-problems. It is shown that due to the difficulty of the block diagonal nature of the relay precoding matrix, sub-problem two cannot be solved with existing methods. It is then solved by converting sub-problem two into a convex optimization problem and a simplified method is proposed to reduce the computational complexity. Simulation results show that the proposed scheme can achieve lower Bit Error Rate (BER) and larger sum rate than other schemes. Furthermore, the BER and the sum rate performance can be improved by increasing the number of antennas for the same number of relays or increasing the number of relays for the same number of antennas.

关键词： Precoding and decoding design iterative algorithm Two-way relaying Bit Error Rate (BER) Sum rate

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Optimal Tracking Control for a Class of Unknown Discrete-time Systems with Actuator Saturation via Data-based ADP algorithm

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Acta Automatica Sinica 2013年第9期39卷 1413-1420页

作者： Rui-Zhuo SONG Wen-Dong XIAO Chang-Yin SUN School of Automation and Electrical Engineering University of Science and Technology Beijing Beijing 100083 China

A novel optimal tracking control method for a class of discrete-time systems with actuator saturation and unknown dynamics is proposed in this paper. The scheme is based on the iterative adaptive dynamic programming (ADP) algorithm. In order to implement the control scheme, a data-based identifier is first constructed for the unknown system dynamics. By introducing the M network, the explicit formula of the steady control is achieved. In order to eliminate the effect of the actuator saturation, a nonquadratic performance functional is presented, and then an iterative ADP algorithm is established to achieve the optimal tracking control solution with convergence analysis. For implementing the optimal control method, neural networks are used to establish the data-based identifier, compute the performance index functional, approximate the optimal control policy and solve the steady control, respectively. Simulation example is provided to verify the effectiveness of the presented optimal tracking control scheme.

关键词： Adaptive dynamic programming (ADP) iterative algorithm optimal tracking control data-based identifier

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