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An automatic, adaptive, information-based algorithm for the extraction of the sEMG envelope

JOURNAL OF ELECTROMYOGRAPHY AND KINESIOLOGY 2018年 42卷 1-9页

作者： Ranaldi, Simone De Marchis, Cristiano Conforto, Silvia Univ Roma TRE Dept Engn Lab Bioengn Biolab3 Via Vito Volterra 62 I-00146 Rome Italy

Surface ElectroMyography (sEMG) is widely used as a non-invasive tool for the assessment of motor control strategies. However, the standardization of the methods used for the estimation of sEMG amplitude is a problem yet to be solved;in most cases, sEMG amplitude is estimated through the extraction of the envelope of the signal via different low-pass filtering procedures with fixed cut-off frequencies chosen by the experimenter. In this work, we have shown how it is not possible to find the optimal choice of the cut-off frequency without any a priori knowledge on the signal;considering this, we have proposed an updated version of an iterative adaptive algorithm already present in literature, aiming to completely automatize the sEMG amplitude estimation. We have compared our algorithm to most of the typical solutions (fixed window filters and the previous version of the adaptive algorithm) for the extraction of the sEMG envelope, showing how the proposed adaptive procedure significantly improves the quality of the estimation, with a lower fraction of variance unexplained by the extracted envelope for different simulated modulating waveforms (p < 0.005). The definition of an entropy-based convergence criterion has allowed for a complete automatization of the process. We infer that this algorithm can ensure repeatability of the estimation of the sEMG amplitude, due to its independence from the experimental choices, so allowing for a quantitative interpretation in a clinical environment.

关键词： sEMG envelope Amplitude estimation adaptive algorithm Entropy sEMG model

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A posteriori error analysis of a fully-discrete finite element method for the wave equation

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JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS 2019年 356卷 231-247页

作者： Guo, Yuling Huang, Jianguo Lai, Junjiang Shanghai Jiao Tong Univ Sch Math Sci Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ MOE LSC Shanghai 200240 Peoples R China Minjiang Univ Dept Math Fuzhou 350108 Fujian Peoples R China

A fully discrete finite element method is proposed for linear wave equations. The spatial discretization is carried out using P-l conforming element, while the temporal discretization is obtained using P-1-continuous discontinuous Galerkin method. Borrowing a novel time reconstruction operator combined with the technique of elliptic reconstruction, a reliable posteriori error bound is developed. Based on this error bound, two adaptive algorithms in time and space separately are proposed. A series of numerical experiments are reported to illustrate the performance of the error bound and the adaptive algorithms proposed. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Fully discrete method Wave equations A posteriori error estimates Reconstruction adaptive algorithm

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A Peak-To-Average Power Ratio Suppression Method for Broadband LEO Satellite Communication 20

A Peak-To-Average Power Ratio Suppression Method for Broadba...

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Proceedings of the 12th International Conference on Education Technology and Computers

作者： Yanfeng Wang Linhai Gu Yanyan Li Hongpeng Liu Macro Net Communication Co. Ltd China Macro Net Communication Co.Ltd China

ISBN: (纸本)9781450388276

The low earth orbit satellite broadband communication adopts OFDM technology, which not only effectively improves the spectrum efficiency, but also facilitates the integration with the 5G. It has far-reaching significance for the construction of 6G global seamless network. High peak to average power ratio (PAPR) for OFDM produces serious nonlinear distortion and spectrum spread of transmission signal in nonlinear transmission channel. On the one hand, pulse shaping technology is used to reduce the PAPR of OFDM. On the other hand, aiming to improve the linear range of power amplifier, the pulse shaping technology is widely used. Under this circumstance, a method CS-PS-DPD (Combination Sine Pulse Shaping and digital pre-distortion) is proposed to reduce the requirement of high PAPR of OFDM signal to the transmission channel linearity. Simulation results show that this method can effectively improve the performance of low earth orbit satellite broadband OFDM communication system.

关键词： low earth orbit (LEO) PAPR adaptive algorithm digital pre-distortion(DPD)

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adaptive FIR Filtering for PAPR Reduction in OFDM Systems

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2019年第8期E102A卷 938-945页

作者： Morita, Hikaru Miyajima, Teruyuki Sugitani, Yoshiki Ibaraki Univ Grad Sch Sci & Engn Hitachi Ibaraki 3168511 Japan Denso Wave Inc Aichi Japan

This study proposes a Peak-to-Average Power Ratio (PAPR) reduction method using an adaptive Finite Impulse Response (FIR) filter in Orthogonal Frequency Division Multiplexing systems. At the transmitter, an iterative algorithm that minimizes the p-norm of a transmitted signal vector is used to update the weight coefficients of the FIR filter to reduce PAPR. At the receiver, the FIR filter used at the transmitter is estimated using pilot symbols, and its effect can be compensated for by using an equalizer for proper demodulation. Simulation results show that the proposed method is superior to conventional methods in terms of the PAPR reduction and computational complexity. It also shows that the proposed method has a trade-off between PAPR reduction and bit error rate performance.

关键词： OFDM PAPR p-norm adaptive algorithm channel estimation

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adaptive Kalman filtering for sensor fault estimation and isolation of satellite attitude control based on descriptor systems

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TRANSACTIONS OF THE INSTITUTE OF MEASUREMENT AND CONTROL 2019年第6期41卷 1686-1698页

作者： Wang, Mao Liang, Tiantian Harbin Inst Technol Ctr Control Theory & Guidance Technol Harbin Heilongjiang Peoples R China

Sensor fault estimation and isolation is significant for an attitude control systems model of a satellite, as it works in a complex environment. The standard unscented Kalman filter algorithm may lose its accuracy when the noise is considerable. Therefore, an adaptive filtering algorithm is proposed based on the sampled-data descriptor model. The performance of the unscented Kalman filter in sensor fault estimation is improved by the adaptive algorithm depending on innovation and the measurement residual, and its convergence is guaranteed. Combining the adaptive unscented Kalman filter with the multiple-model adaptive estimation, a sensor fault isolation method is proposed. Finally, simulation examples show that this algorithm has better estimating accuracy and isolation results.

关键词： adaptive algorithm descriptor system fault estimation and isolation Kalman filter sampled-data system

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Research of Fall Detection and Fall Prevention Technologies: A Systematic Review

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IEEE ACCESS 2019年 7卷 77702-77722页

作者： Ren, Lingmei Peng, Yanjun Shandong Univ Sci & Technol Dept Comp Sci Jinan 266590 Shandong Peoples R China

Falls are abnormal activity events that occur infrequently;however, they are serious health problems among elderly individuals. With the advancements of technologies, falls have been widely studied by scientific researchers to minimize serious consequences and negative impacts. Fall detection and fall prevention are two strategies to tackle fall issues with a variety of sensing techniques and classifier models. Currently, many reviews on fall-related technologies have been presented and analyzed;however, most of them give surveys on the subfield of fall-related systems, while others are not extensive and comprehensive reviews. In fact, the latest researches have a newtrend of fusion-based methods to improve the performance of the fall-related systems based on a combination of different sensors or classifier models. adaptive threshold and radio frequency-based systems are also researched and proposed recently, which are seldom mentioned in other reviews. Therefore, a global taxonomy for current fall-related studies from four aspects, including current literature reviews, fall detection, and prevention systems based on different sensor apparatus and analytic algorithm, low power techniques, and sensor placements for fall-related systems are conducted in this paper. Several research challenges and issues in the fall-related field are also discussed and analyzed. The objective of this review paper is to conclude and provide a good position of current fall-related studies to inspire researchers in this field.

关键词： adaptive algorithm classification algorithms fall detection fall prevention low power techniques sensing techniques

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Collaborative block-delay Volterra filters for nonlinear acoustic echo cancellation

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APPLIED ACOUSTICS 2019年 156卷 83-91页

作者： Lu, Wenxia Zhang, Lijun Northwestern Polytech Univ Sch Marine Sci & Technol CIAIC Xian 710072 Shaanxi Peoples R China

A new nonlinear adaptive filtering strategy, collaborative block-delay Volterra filters (CBDVF), is proposed for nonlinear acoustic echo cancellation (NAEC). This paper focuses on the theoretical reasonability and practical feasibility of the proposed algorithm. Specifically, a practice-friendly adaptive filtering architecture is designed to ensure that the linear filter is considered a priority to play the most important role in estimating the echo path while the nonlinear filters will further perfect the modeling nonlinearities. A CBDVF is obtained by a combination of linear filter and different nonlinear filtering blocks of different time-delay length, where the nonlinear time-delay blocks are activated or deactivated automatically and adaptively to fulfil their tasks via some adaptive shrinkage factors. Theoretical performance analysis is also conducted to characterize the stability condition of the proposed algorithm. Simulations with an acoustic echo cancellation problem demonstrate the effectiveness of the proposed CBDVF. Moreover, the evaluation for CBDVF is completed for a real NAEC scenario. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Nonlinear acoustic echo cancellation collaborative block-delay Volterra filter adaptive algorithm

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Distributed Average Tracking for Lipschitz-Type of Nonlinear Dynamical Systems

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IEEE TRANSACTIONS ON CYBERNETICS 2019年第12期49卷 4140-4152页

作者： Zhao, Yu Liu, Yongfang Wen, Guanghui Yu, Xinghuo Chen, Guanrong Northwestern Polytech Univ Res & Dev Inst Shenzhen 518057 Peoples R China Northwestern Polytech Univ Sch Automat Xian 710129 Shaanxi Peoples R China RMIT Univ Sch Engn Melbourne Vic 3001 Australia Southeast Univ Sch Math Nanjing 210096 Jiangsu Peoples R China City Univ Hong Kong Dept Elect Engn Hong Kong Peoples R China

In this paper, a distributed average tracking (DAT) problem is studied for Lipschitz-type of nonlinear dynamical systems. The objective is to design DAT algorithms for locally interactive agents to track the average of multiple reference signals. Here, in both dynamics of agents and reference signals, there is a nonlinear term satisfying a Lipschitz-type condition. Three types of DAT algorithms are designed. First, based on state-dependent-gain design principles, a robust DAT algorithm is developed for solving DAT problems without requiring the same initial condition. Second, by using a gain adaption scheme, an adaptive DAT algorithm is designed to remove the requirement that global information, such as the eigenvalue of the Laplacian and the Lipschitz constant, is known to all agents. Third, to reduce chattering and make the algorithms easier to implement, a couple of continuous DAT algorithms based on time-varying or time-invariant boundary layers are designed, respectively, as a continuous approximation of the aforementioned discontinuous DAT algorithms. Finally, some simulation examples are presented to verify the proposed DAT algorithms.

关键词： adaptive algorithm continuous algorithm distributed average tracking (DAT) nonlinear dynamics

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OPTIMALITY OF A STANDARD adaptive FINITE ELEMENT METHOD FOR THE STOKES PROBLEM

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SIAM JOURNAL ON NUMERICAL ANALYSIS 2019年第3期57卷 1124-1157页

作者： Feischl, Michael Univ Bonn Inst Numer Simulat D-53115 Bonn Germany

We prove that the a standard adaptive algorithm for the Taylor-Hood discretization of the stationary Stokes problem converges with optimal rate. This is done by developing an abstract framework for quite general problems, which allows us to prove general quasi-orthogonality proposed in [C. Carstensen et al., Comput. Math. Appl., 67 (2014), pp. 1195-1253]. This property is the main obstacle towards the optimality proof and therefore is the main focus of this work. The key ingredient is a new connection between the mentioned quasi-orthogonality and LU-factorization of infinite matrices.

关键词： Stokes adaptive algorithm optimality finite element method quasi-orthogonality

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Hybrid Inverse Parameter Identification of Fully Coupled Ductile Damage Model for Steel Sheet DP600 with Two Different algorithms: Trust Region and Genetic algorithms

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JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE 2019年第5期28卷 3149-3156页

作者： Cao, Ke Yue, Zhen-ming Zhao, Xiao-di Qi, Jiashuo Gao, Jun Shandong Univ Sch Mech Elect & Informat Engn Weihai 264209 Peoples R China

Ductile damage model has been widely regarded as a valuable method to predict the failure of sheet metal. Based on the thermodynamic theory and continuum damage mechanics, the fully coupled ductile damage model can be developed, which also can better predict the initiation and growth of the fracture. But the identifications of model parameters with theoretical methodology are difficult due to the complex coupling relationships existing among all state variables. The inverse methodology is regarded as a good method to resolve the problem. In this paper, the recently proposed fully coupled ductile damage model is chosen to investigate the deformation behavior of DP600 steel, in which the mixed saturation isotropic and kinematic hardenings are taken into account and fully coupled with the ductile damage. During the identification process, the least square formula of the error between experimental and numerical results is selected as the target function. The trust region algorithm and genetic algorithm are used with the help of MATLAB for the identification of three damage parameters. Finally, by comparing the experimental and numerical results, the validations of two algorithms are proved. The efficiency of the optimization process with trust region algorithm is higher, but with lower accuracy. Meanwhile, the optimization process is greatly affected by the chosen initial values of the ductile damage parameters.

关键词： adaptive algorithm ductile damage identification inverse methodology simulation

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