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STABILIZATION OF DISCRETE-TIME NONLINEAR UNCERTAIN SYSTEMS BY FEEDBACK BASED ON ls algorithm

SIAM JOURNAL ON CONTROL AND OPTIMIZATION 2013年第2期51卷 1128-1151页

作者： Li, Chanying Lam, James Chinese Acad Sci Acad Math & Syst Sci Natl Ctr Math & Interdisciplinary Sci Beijing 100190 Peoples R China Univ Hong Kong Dept Mech Engn Hong Kong Hong Kong Peoples R China

This paper is concerned with the use of the least squares (ls) algorithm to design a feedback control law to stabilize a basic class of discrete-time nonlinear uncertain systems. The result shows that if a certain polynomial criterion is satisfied, the system can be stabilized by feedback based on the ls algorithm for Gaussian distributed noise and unknown parameters. This result thus provides an answer to the question of what are the fundamental limitations of the discrete-time adaptive nonlinear control. This issue of feedback capability has been an open problem for more than ten years since it was put forward.

关键词： feedback capability ls algorithm nonlinear systems uncertainties stabilization

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ls algorithm for Semi-online Scheduling Jobs with Nondecreasing Release Times and Nondecreasing Processing Times

LS Algorithm for Semi-online Scheduling Jobs with Nondecreas...

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2015 International Conference on Computer Information Systems and Industrial Applications(CISIA2015)

作者： F.Tang J.Nie School of Industry Hunan Normal University Dept.of Math Hunan Normal University

ISBN: (纸本)9781510805750

In this paper,semi-online scheduling jobs with nondecreasing release times and non-increasing processing times on m identical parallel machines is *** aim is to minimize the last completion time of all *** is proved that,for any m identical parallel machines,3/2-l/2m is an upper bound of the worst case performance ratio of List Scheduling(ls)algorithm.

关键词： release time processing time semi-online ls algorithm

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Analysis on the convergence property of the sub-Rls algorithm

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IEICE TRANSACTIONS ON FUNDAMENTAls OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2001年第10期E84A卷 2591-2594页

作者： Fujii, K Muneyasu, M Hinamoto, T Tanaka, Y Fujitsu Labs Ltd Wireless Commun Syst Lab L41 Kawasaki Kanagawa 2118588 Japan Hiroshima Univ Fac Engn Higashihiroshima 7398527 Japan Himeji Inst Technol Fac Engn Himeji Hyogo 6712167 Japan

The sub-recursive least squares (sub-Rls) algorithm estimates the coefficients of adaptive filter under the least squares (ls) criterion, however, does not require the calculation of inverse matrix. The sub-Rls algorithm, based on the different principle from the Rls algorithm, still provides a convergence property similar to that of the Rls algorithm. This paper first rewrites the convergence condition of the sub-Rls algorithm, and then proves that the convergence property of the sub-Rls algorithm successively approximates that of the Rls algorithm on the convergence condition.

关键词： sub-Rls algorithm convergence condition ls algorithm Rls algorithm maximum eigenvalue

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Optimal adaptive controller for systems with delay

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INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING 2004年第9-10期18卷 799-819页

作者： Lo, KM Kimura, H Tsing Hua Univ Sch Software Beijing 100084 Peoples R China Univ Tokyo Grad Sch Frontier Sci Dept Complex Sci & Engn Bunkyo Ku Tokyo 1138656 Japan Inst Phys & Chem Res Biomimet Control Ctr Moriyama Ku Nagoya Aichi Japan

Stochastic adaptive d-step-ahead optimal control is analyzed in this paper. An adaptive controller using the least squares (ls) algorithm and an input matching technique is proposed to combine the globally convergent estimation character of the adaptive tracking and optimally-based input specification behavior by using a d-step-ahead quadratic cost function. The identification convergence rate of the parameter estimation is based on the ls algorithm. With adaptive control, the d-step-ahead closed-loop stochastic system is globally stable and the adaptive controller converges to the d-step-ahead optimal controller. Lastly, the consistency of parameter estimators is analyzed and the convergence rate of parameter estimation is obtained. Copyright (C) 2004 John Wiley Sons, Ltd.

关键词： d-step-ahead stochastic systems ls algorithm optimal adaptive control convergence rate globally stable

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Sparse/dense channel estimation with non-zero tap detection for 60-GHz beam training

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IET COMMUNICATIONS 2014年第11期8卷 2044-2053页

作者： Gao, Bo Xiao, Zhenyu Zhang, Changming Jin, Depeng Zeng, Lieguang Tsinghua Univ Dept Elect Engn State Key Lab Microwave & Digital Commun Beijing 100084 Peoples R China Beihang Univ Sch Elect & Informat Engn Beijing 100191 Peoples R China

Estimation of the multipath channel in 60-GHz communications is challenging, because the channel may be sparse or dense during beam training. Specifically, because of the variation of the number of non-zero taps, it is hard for common estimators to obtain robust and prominent performance. In order to address this problem, the authors propose a sparse/dense channel estimation with non-zero tap detection (SDCE-NTD). The estimation is conducted in a three-stage fashion, including initial estimation with the unstructured least-square (ls) algorithm, non-zero-tap detection with the generalised likelihood ratio test approach, and posterior estimation with the structured ls algorithm. The false-alarm and detection probability of the tap detector, as well as the mean square error (MSE) of SDCE-NTD, are derived and confirmed via simulations. Comparisons are conducted between SDCE-NTD and the common estimators in the beam training scenarios, where both dense and sparse channels exist. Results show that SDCE-NTD reveals a significant gain in terms of MSE over both the conventional ls algorithm, which does not exploit the sparse nature of the channel, and the matching pursuit algorithm, which endeavours to exploit the sparsity. In addition, it is also demonstrated that the proposed estimator can approach the lower bound with high signal-to-noise ratio.

关键词： channel estimation multipath channels least squares approximations probability mean square error methods frequency 60 GHz matching pursuit algorithm MSE mean square error detection probability false-alarm probability posterior estimation generalised likelihood ratio test approach ls algorithm unstructured least-square algorithm SDCE-NTD multipath channel estimation beam training nonzero tap detection sparse-dense channel estimation

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A novel data-driven model based parameter estimation of nonlinear systems

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JOURNAL OF SOUND AND VIBRATION 2019年 453卷 188-200页

作者： Ge, Xiaobiao Luo, Zhong Ma, Ying Liu, Haopeng Zhu, Yunpeng Northeastern Univ Sch Mech Engn & Automat Shenyang Liaoning Peoples R China Northeastern Univ Key Lab Vibrat & Control Aeroprop Syst Minist Educ China Shenyang Liaoning Peoples R China Univ Sheffield Dept Automat Control & Syst Engn Sheffield S Yorkshire England

In practice, it is usually difficult to estimate the characteristic parameters of a system due to the system nonlinearity and uncertainty. To address this problem, in this study, the characteristic parameters of a nonlinear system are identified by using a data driven method based on the best discretization of the Nonlinear Differential Equation (NDE) model of the system. The best discretization of a NDE model is firstly determined, and then the discretized model, known as the Nonlinear Auto Regressive with eXegenous input (NARX) model, is determined by using the Least Squares (ls) algorithm from the input and output data of system. A case study is discussed to validate the proposed system parameter identification method, where the characteristic parameters of a rotating blade-casing system are evaluated under a bandwidth rub impact in the horizontal direction with noise. The result shows that the identified model can be used to describe the characteristics of the underlying system accurately, which provides a reliable model for the dynamic analysis, control of rotating blade-casing system. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Discretization method ls algorithm Rotating blade-casing system System identification

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Pilot Tones Optimization Using Artificial Bee Colony algorithm for MIMO-OFDM Systems

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WIRELESS PERSONAL COMMUNICATIONS 2013年第1期71卷 151-163页

作者： Seyman, Muhammet Nuri Taspinar, Necmi Kirikkale Univ Dept Elect Commun TR-71450 Kirikkale Turkey Erciyes Univ Dept Elect & Elect Engn TR-38039 Kayseri Turkey

How to design the pilot tones that are used in channel estimation has a significant effect on the estimation performance. To achieve good performance in least square (ls) algorithm, we propose the artificial bee colony (ABC) algorithm for optimizing the placement of pilot tones in MIMO-OFDM systems. We also derive the upper bound of mean square error of ls estimation with the help of Gerschgorin disc theorem for fitness function of ABC algorithm. The results show that designing pilot tones using the ABC algorithm outperforms other considered placement strategies in terms of high system performance and low computational complexity.

关键词： MIMO-OFDM Channel estimation ABC algorithm ls algorithm

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Elastic properties evaluation of composite metal foams

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MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES 2024年第7期52卷 4689-4709页

作者： Keleshteri, M. M. Jelovica, J. Univ British Columbia Dept Mech Engn Vancouver BC Canada Univ British Columbia Dept Mech Engn & Civil Engn Vancouver BC Canada

Composite metal foams (CMFs) are a new class of closed-cell porous materials that can be produced by distributing metallic spheres in a metallic matrix. CMFs could offer better mechanical performance in comparison to the conventional metal foams due to the uniform shape and even distribution of voids. To evaluate elastic properties of CMFs, the conventional theoretical approaches for periodic models are not good candidates due to the random distribution of voids in these materials. Thus, in this research, first, a three-dimensional model is developed based on the Lubachevsky and Stillinger (ls) approach, which is then used for the FE analysis. Using homogenization technique, the elastic properties of the CMFs are evaluated focusing here on elastic modulus and Poisson's ratio. Comparing results against experimental results shows a very good agreement. In this paper, for the first time, effects of geometrical and material parameters such as thickness of the spheres, microporosity in the wall of spheres and matrix, matrix materials, and diameter of the spheres on the elastic properties of CMFs are examined. It is observed that the microporosity in the matrix has higher effect on the elastic modulus of the CMFs than the microporosity in the wall of the spherical particles.

关键词： CMF metal foams composites FEM homogenization ls algorithm

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Pilot tones design using Grey Wolf Optimizer for OFDM-IDMA system

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PHYSICAL COMMUNICATION 2017年第Part1期25卷 259-267页

作者： Simsir, Sakir Taspinar, Necmi Erciyes Univ Fac Engn Dept Elect & Elect Engn TR-38039 Kayseri Turkey

Since the channel estimation performance is affected directly by the positions of pilot tones, the optimization of pilot placement process known as having quite important role on minimizing the estimation errors has become a significant task for the multicarrier transmission technologies. Therefore, we propose Grey Wolf Optimizer (GWO) for pilot tones optimization to enhance the performance of Least Squares (ls) algorithm employed for channel estimation in Orthogonal Frequency Division Multiplexing - Interleave Division Multiple Access (OFDM-IDMA) system. Besides, the upper bound of Mean Square Error (MSE) which can be derived through Gershgorin disc theorem is used as an objective function of GWO to get rid of computing matrix inversion that is indispensable when computing MSE. In the simulations, our proposed GWO based pilot design method is compared to random, equispaced, Genetic algorithm (GA) and Particle Swarm Optimization (PSO) based pilot placement strategies in terms of MSE and bit error rate (BER) criteria. The simulation results in which our proposed technique leaves behind the other considered strategies demonstrates that GWO based pilot design method is a promising pilot placement strategy for OFDM-IDMA system because of its high performance and low computational complexity. (C) 2017 Elsevier B.V. All rights reserved.

关键词： Pilot tones design Channel estimation PSO GWO ls algorithm OFDM-IDMA

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Efficiency Optimization of IPOP DC/DC System for HEV

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IEEE ACCESS 2021年 9卷 31553-31561页

作者： Lu, Fengwang He, Liangzong Tan, Qingyang Zhou, Hongyan Xiamen Univ Sch Aeronaut & Astronaut Xiamen 361000 Peoples R China

Input parallel output parallel (IPOP) DC/DC system is widely utilized in many occasions like data center and hybrid electric vehicle (HEV). However, the efficiency characteristics of different converters usually differs from each other, and the conventional control strategy has difficult to realize efficient conversion of overall power of the system. To address this issue, Buck converter is taken as the module and whose efficiency model under current continuous conduction mode (CCM) is presented. Meantime, parameter identification method based on least square (ls) algorithm is proposed as well. In order to realize the efficiency optimization of the whole parallel system, the constraint conditions of each module are analyzed, and the current distribution calculation method based on sequential quadratic programming (SQP) algorithm for the parallel system is introduced. On this basis, a control strategy of proportional current distribution (PCD) is proposed, which not only ensures that the parallel system can always run as efficiently as possible under different loads, but also realizes the flexible switching between the current-sharing mode and current distribution mode. Finally, the simulation and experimental results prove that the proposed method can achieve 4.46% higher efficiency than conventional method within the given power range of each converter, and realize the efficiency optimization of the IPOP DC/DC system to the greatest extent.

关键词： Optimization Current distribution Hybrid electric vehicles Power distribution Mathematical model Buck converters Parameter estimation Efficiency optimization ls algorithm proportional current distribution IPOP DC DC converter SQP algorithm

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