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A novel dynamic step size LMS optimization scheme for interference reducing in FBMC-QAM
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作者 DONG Qiyang MA Tianming +1 位作者 JIANG Xiaoxiao MA Honglei 《High Technology Letters》 EI CAS 2024年第3期290-296,共7页
Filter bank multicarrier quadrature amplitude modulation(FBMC-QAM)will encounter inter-ference and noise during the process of channel transmission.In order to suppress the interference in the communication system,cha... Filter bank multicarrier quadrature amplitude modulation(FBMC-QAM)will encounter inter-ference and noise during the process of channel transmission.In order to suppress the interference in the communication system,channel equalization is carried out at the receiver.Given that the con-ventional least mean square(LMS)equilibrium algorithm usually suffer from drawbacks such as the inability to converge quickly in large step sizes and poor stability in small step sizes when searching for optimal weights,in this paper,a design scheme for adaptive equalization with dynamic step size LMS optimization is proposed,which can further improve the convergence and error stability of the algorithm by calling the Sigmoid function and introducing three new parameters to control the range of step size values,adjust the steepness of step size,and reduce steady-state errors in small step sta-ges.Theoretical analysis and simulation results demonstrate that compared with the conventional LMS algorithm and the neural network-based residual deep neural network(Res-DNN)algorithm,the adopted dynamic step size LMS optimization scheme can not only obtain faster convergence speed,but also get smaller error values in the signal recovery process,thereby achieving better bit error rate(BER)performance. 展开更多
关键词 filter bank multicarrier quadrature amplitude modulation(FBMC-QAM) adap-tive equalization least mean square(LMS) dynamic step size
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Effect of Time Step Size and Turbulence Model on the Open Water Hydrodynamic Performance Prediction of Contra-Rotating Propellers 被引量:15
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作者 王展智 熊鹰 《China Ocean Engineering》 SCIE EI CSCD 2013年第2期193-204,共12页
A growing interest has been devoted to the contra-rotating propellers (CRPs) due to their high propulsive efficiency, torque balance, low fuel consumption, low cavitations, low noise performance and low hull vibrati... A growing interest has been devoted to the contra-rotating propellers (CRPs) due to their high propulsive efficiency, torque balance, low fuel consumption, low cavitations, low noise performance and low hull vibration. Compared with the single-screw system, it is more difficult for the open water performance prediction because forward and aft propellers interact with each other and generate a more complicated flow field around the CRPs system. The current work focuses on the open water performance prediction of contra-rotating propellers by RANS and sliding mesh method considering the effect of computational time step size and turbulence model. The validation study has been performed on two sets of contra-rotating propellers developed by David W Taylor Naval Ship R & D center. Compared with the experimental data, it shows that RANS with sliding mesh method and SST k-ω turbulence model has a good precision in the open water performance prediction of contra-rotating propellers, and small time step size can improve the level of accuracy for CRPs with the same blade number of forward and aft propellers, while a relatively large time step size is a better choice for CRPs with different blade numbers. 展开更多
关键词 contra-rotating propeller open water performance RANS time step size turbulence model
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Noise cancellation of a multi-reference full-wave magnetic resonance sounding signal based on a modified sigmoid variable step size least mean square algorithm 被引量:1
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作者 TIAN Bao-feng ZHOU Yuan-yuan +2 位作者 ZHU Hui JIANG Chuan-dong YI Xiao-feng 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第4期900-911,共12页
Nano-volt magnetic resonance sounding(MRS) signals are sufficiently weak so that during the actual measurement, they are affected by environmental electromagnetic noise, leading to inaccuracy of the extracted characte... Nano-volt magnetic resonance sounding(MRS) signals are sufficiently weak so that during the actual measurement, they are affected by environmental electromagnetic noise, leading to inaccuracy of the extracted characteristic parameters and hindering effective inverse interpretation. Considering the complexity and non-homogeneous spatial distribution of environmental noise and based on the theory of adaptive noise cancellation, a model system for noise cancellation using multi-reference coils was constructed to receive MRS signals. The feasibility of this system with theoretical calculation and experiments was analyzed and a modified sigmoid variable step size least mean square(SVSLMS) algorithm for noise cancellation was presented. The simulation results show that, the multi-reference coil method performs better than the single one on both signal-to-noise ratio(SNR) improvement and signal waveform optimization after filtering, under the condition of different noise correlations in the reference coils and primary detecting coils and different SNRs. In particular, when the noise correlation is poor and the SNR<0, the SNR can be improved by more than 8 dB after filtering with multi-reference coils. And the average fitting errors for initial amplitude and relaxation time are within 5%. Compared with the normalized least mean square(NLMS) algorithm and multichannel Wiener filter and processing field test data, the effectiveness of the proposed method is verified. 展开更多
关键词 magnetic resonance SOUNDING SIGNAL MULTI-REFERENCE coils adaptive noise CANCELLATION SIGMOID variable step size least mean SQUARE (SVSLMS)
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Novel LMS adaptive filtering algorithm with variable step size 被引量:1
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作者 李继明 马骥 +1 位作者 王洋 程学珍 《Journal of Measurement Science and Instrumentation》 CAS 2012年第3期239-242,共4页
By analyzing algorithms available for variable step size least mean square(LMS)adaptive filter,a new modified LMS adaptive filtering algorithm with variable step size is proposed,along with performance analysis based ... By analyzing algorithms available for variable step size least mean square(LMS)adaptive filter,a new modified LMS adaptive filtering algorithm with variable step size is proposed,along with performance analysis based on different parameters.Compared with the existing algorithms through the simulation,the proposed algorithm has faster convergence speed and smaller steady state error. 展开更多
关键词 adaptive filter variable step size least mean square(LMS)
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Step Sized DGS结构的毫米波带通滤波器的设计
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作者 许航 王正武 《弹箭与制导学报》 CSCD 北大核心 2005年第S7期336-338,共3页
文中利用一种渐变尺寸的 DGS(Defected Ground Structure)结构的带阻特性,以改善毫米波滤波器的阻带性能.仿真及实验结果证明了优化的渐变尺寸周期 DGS 结构能有效地改善滤波器带外抑制特性,同时对通带内插入损耗影响较小.
关键词 DGS结构 滤波器 渐变尺寸
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Some new step-size rules for optimization problems 被引量:4
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作者 吴庆军 韦增欣 《Journal of Shanghai University(English Edition)》 CAS 2007年第2期135-141,共7页
The step-size procedure is very important for solving optimization problems. The Armijo step-size rule, the Armijo-Goldstein step-size rule and the Wolfe-Powell step-size rule are three well-known line search methods.... The step-size procedure is very important for solving optimization problems. The Armijo step-size rule, the Armijo-Goldstein step-size rule and the Wolfe-Powell step-size rule are three well-known line search methods. On the basis of the above three types of line search methods and the idea of the proximal point methods, a new class of step-size rules was proposed. Instead of a single objective function f, f +1/2(x - xk)^TBk(x-Xk) was used as the merit function in iteration k, where Sk is a given symmetric positive definite matrix. The existence of the steplength for the new rules was proved. Some convergence properties were also discussed. 展开更多
关键词 unconstrained minimization step-size procedures global convergence
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Active micro-vibration control based on improved variable step size LMS algorithm 被引量:1
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作者 Li Xiangmin Fang Yubin +2 位作者 Zhu Xiaojin Huang Yonghui Zhou Yijia 《High Technology Letters》 EI CAS 2020年第2期178-187,共10页
The contradiction of variable step size least mean square(LMS)algorithm between fast convergence speed and small steady-state error has always existed.So,a new algorithm based on the combination of logarithmic and sym... The contradiction of variable step size least mean square(LMS)algorithm between fast convergence speed and small steady-state error has always existed.So,a new algorithm based on the combination of logarithmic and symbolic function and step size factor is proposed.It establishes a new updating method of step factor that is related to step factor and error signal.This work makes an analysis from 3 aspects:theoretical analysis,theoretical verification and specific experiments.The experimental results show that the proposed algorithm is superior to other variable step size algorithms in convergence speed and steady-state error. 展开更多
关键词 adaptive filtering variable step size least mean square(LMS)algorithm logarithmic and SYMBOLIC functions convergence and STEADY state error ACTIVE CONTROL of micro vibration
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A Simple Method of Calculating the Optimal Step Size in 4DVAR Technique
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作者 王云峰 伍荣生 +1 位作者 王元 潘益农 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2000年第3期433-444,共12页
In four—dimensional variational data assimilation (4DVAR) technology, how to calculate the optimal step size is always a very important and indeed difficult task. It is directly related to the computational efficienc... In four—dimensional variational data assimilation (4DVAR) technology, how to calculate the optimal step size is always a very important and indeed difficult task. It is directly related to the computational efficiency. In this research, a new method is proposed to calculate the optimal step size more effectively. Both nonlinear one—dimensional advection equation and two—dimensional inertial wave equation are used to test and compare the influence of different methods of the optimal step size calculations on the iteration steps, as well as the simulation results of 4DVAR processes. It is in evidence that the different methods have different influences. The calculating method is very important to determining whether the iteration is convergent or not and whether the convergence rate is large or small. If the calculating method of optimal step size is properly determined as demonstrated in this paper, then it can greatly enlarge the convergence rate and further greatly decrease the iteration steps. This research is meaningful since it not only makes an important improvement on 4DVAR theory, but also has useful practical application in improving the computational efficiency and saving the computational time. Key words 4DVAR - Optimal step size - Iterative convergence rate This work was supported by the National Natural Science Foundation under grants: 49735180 and 49675259, the “973 Project? CHERES(G 1998040907), the Project of Natural Science Foundation of Jiangsu Province(BK99020), and the Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars. 展开更多
关键词 4DVAR Optimal step size Iterative convergence rate
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An NLMS algorithm with optimized preparatory step-size parameters for SQUID-based MCG data processing
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作者 李倬 陈赓华 +2 位作者 张利华 杨乾声 冯稷 《Chinese Physics B》 SCIE EI CAS CSCD 2006年第2期310-314,共5页
We present a new least-mean-square algorithm of adaptive filtering to improve the signal to noise ratio for magneto-cardiography data collected with high-temperature SQUID-based magnetometers. By frequently adjusting ... We present a new least-mean-square algorithm of adaptive filtering to improve the signal to noise ratio for magneto-cardiography data collected with high-temperature SQUID-based magnetometers. By frequently adjusting the adaptive parameter a go systematic optimum values in the course of the programmed procedure, the convergence is accelerated with a highest speed and the minimum steady-state error is obtained simultaneously. This algorithm may be applied to eliminate other non-steady relevant noises as well. 展开更多
关键词 MAGNETOCARDIOGRAPHY optimal step size
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An Effective Runge-Kutta Optimizer Based on Adaptive Population Size and Search Step Size
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作者 Ala Kana Imtiaz Ahmad 《Computers, Materials & Continua》 SCIE EI 2023年第9期3443-3464,共22页
A newly proposed competent population-based optimization algorithm called RUN,which uses the principle of slope variations calculated by applying the Runge Kutta method as the key search mechanism,has gained wider int... A newly proposed competent population-based optimization algorithm called RUN,which uses the principle of slope variations calculated by applying the Runge Kutta method as the key search mechanism,has gained wider interest in solving optimization problems.However,in high-dimensional problems,the search capabilities,convergence speed,and runtime of RUN deteriorate.This work aims at filling this gap by proposing an improved variant of the RUN algorithm called the Adaptive-RUN.Population size plays a vital role in both runtime efficiency and optimization effectiveness of metaheuristic algorithms.Unlike the original RUN where population size is fixed throughout the search process,Adaptive-RUN automatically adjusts population size according to two population size adaptation techniques,which are linear staircase reduction and iterative halving,during the search process to achieve a good balance between exploration and exploitation characteristics.In addition,the proposed methodology employs an adaptive search step size technique to determine a better solution in the early stages of evolution to improve the solution quality,fitness,and convergence speed of the original RUN.Adaptive-RUN performance is analyzed over 23 IEEE CEC-2017 benchmark functions for two cases,where the first one applies linear staircase reduction with adaptive search step size(LSRUN),and the second one applies iterative halving with adaptive search step size(HRUN),with the original RUN.To promote green computing,the carbon footprint metric is included in the performance evaluation in addition to runtime and fitness.Simulation results based on the Friedman andWilcoxon tests revealed that Adaptive-RUN can produce high-quality solutions with lower runtime and carbon footprint values as compared to the original RUN and three recent metaheuristics.Therefore,with its higher computation efficiency,Adaptive-RUN is a much more favorable choice as compared to RUN in time stringent applications. 展开更多
关键词 Optimization Runge Kutta(RUN) metaheuristic algorithm exploration EXPLOITATION population size adaptation adaptive search step size
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Interval of effective time-step size for the numerical computation of nonlinear ordinary differential equations
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作者 CAO Jing LI Jian-Ping ZHANG Xin-Yuan 《Atmospheric and Oceanic Science Letters》 CSCD 2017年第1期17-20,共4页
The computational uncertainty principle states that the numerical computation of nonlinear ordinary differential equations(ODEs) should use appropriately sized time steps to obtain reliable solutions.However,the int... The computational uncertainty principle states that the numerical computation of nonlinear ordinary differential equations(ODEs) should use appropriately sized time steps to obtain reliable solutions.However,the interval of effective step size(IES) has not been thoroughly explored theoretically.In this paper,by using a general estimation for the total error of the numerical solutions of ODEs,a method is proposed for determining an approximate IES by translating the functions for truncation and rounding errors.It also illustrates this process with an example.Moreover,the relationship between the IES and its approximation is found,and the relative error of the approximation with respect to the IES is given.In addition,variation in the IES with increasing integration time is studied,which can provide an explanation for the observed numerical results.The findings contribute to computational step-size choice for reliable numerical solutions. 展开更多
关键词 Ordinary differential equations interval of effective step size computational uncertainty principle integration time relative error
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Study of Variable Step Size LMS Adaptive Algorithm Based on Variable Region
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作者 曲永印 邵世煌 +1 位作者 姜林 周振雄 《Journal of Donghua University(English Edition)》 EI CAS 2006年第4期32-35,共4页
This paper puts forward a new variable step size LMS adaptive algorithm based on variable region. The step size p(k) in the algorithm varies with the variation of the region of deviation e (k) to ensure the optimi... This paper puts forward a new variable step size LMS adaptive algorithm based on variable region. The step size p(k) in the algorithm varies with the variation of the region of deviation e (k) to ensure the optimization of the three performance objectives including initial convergent speed, trace ability of the time-varying system and steady disregulation. The paper demonstrates the convergence of the algorithm accompanied by random noise, 展开更多
关键词 variable step size LMS algorithm variable region CONVERGENCE model identification.
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Optimized Runge-Kutta Methods with Automatic Step Size Control for Compressible Computational Fluid Dynamics
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作者 Hendrik Ranocha Lisandro Dalcin +1 位作者 Matteo Parsani David I.Ketcheson 《Communications on Applied Mathematics and Computation》 2022年第4期1191-1228,共38页
We develop error-control based time integration algorithms for compressible fluid dynam-ics(CFD)applications and show that they are efficient and robust in both the accuracy-limited and stability-limited regime.Focusi... We develop error-control based time integration algorithms for compressible fluid dynam-ics(CFD)applications and show that they are efficient and robust in both the accuracy-limited and stability-limited regime.Focusing on discontinuous spectral element semidis-cretizations,we design new controllers for existing methods and for some new embedded Runge-Kutta pairs.We demonstrate the importance of choosing adequate controller parameters and provide a means to obtain these in practice.We compare a wide range of error-control-based methods,along with the common approach in which step size con-trol is based on the Courant-Friedrichs-Lewy(CFL)number.The optimized methods give improved performance and naturally adopt a step size close to the maximum stable CFL number at loose tolerances,while additionally providing control of the temporal error at tighter tolerances.The numerical examples include challenging industrial CFD applications. 展开更多
关键词 Explicit Runge-Kutta methods step size control Compressible Euler equations Compressible Navier-Stokes equations hp-adaptive spatial discretizations
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Convergence Properties and Step Size Estimation for MLMS Algorithm
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作者 侯维岩 邓记才 +1 位作者 汪敏 陈伯时 《Journal of Shanghai University(English Edition)》 CAS 2003年第4期410-413,共4页
According to the exact expression of the maladjustment, an equation for calculating the boundary of step-size in MLMS algorithm is derived and the relationship between the convergence rate and step-size is discussed i... According to the exact expression of the maladjustment, an equation for calculating the boundary of step-size in MLMS algorithm is derived and the relationship between the convergence rate and step-size is discussed in detail. It is shown that the threshold of the step-size is constrained by maladjustment. Three different properties are presented between the LMS and MLMS algorithms based on comparison. It is indicated that MLMS does not differ significantly from LMS when the given maladjustment is small. 展开更多
关键词 step-size THRESHOLD MLMS-algorithm maladjustment.
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Joint receiving mechanism based on blind equalization with variable step size for M-QAM modulation
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作者 卢继华 Abdallah Elhirtsia AHMED +1 位作者 王晓华 Kheddar BOUDJEMAA 《Journal of Beijing Institute of Technology》 EI CAS 2015年第3期381-386,共6页
The problem of inter symbol interference( ISI) in wireless communication systems caused by multipath propagation when using high order modulation like M-Q AMis solved. Since the wireless receiver doesn't require a ... The problem of inter symbol interference( ISI) in wireless communication systems caused by multipath propagation when using high order modulation like M-Q AMis solved. Since the wireless receiver doesn't require a training sequence,a blind equalization channel is implemented in the receiver to increase the throughput of the system. To improve the performances of both the blind equalizer and the system,a joint receiving mechanismincluding variable step size( VSS) modified constant modulus algorithms( MC-MA) and modified decision directed modulus algorithms( MD DMA) is proposed to ameliorate the convergence speed and mean square error( MSE) performance and combat the phase error when using high order QAM modulation. The VSS scheme is based on the selection of step size according to the distance between the output of the equalizer and the desired output in the constellation plane. Analysis and simulations showthat the performance of the proposed VSS-MCMA-MD DMA mechanismis better than that of algorithms with a fixed step size. In addition,the MCMA-MDDMA with VSS can performthe phase recovery by itself. 展开更多
关键词 inter symbol interference(ISI) modified constant modulus algorithm(MCMA) modified decision directed modulus algorithm(MDDMA) variable step size blind equalization phase rotation
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Computational uncertainty and optimal grid size and time step of the Lax-Friedrichs scheme for the 1D advection equation
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作者 Jing Cao Jianping Li Yanjie Li 《Atmospheric and Oceanic Science Letters》 CSCD 2023年第3期46-51,共6页
本文对于应用Lax-Friedrichs格式数值求解一维平流方程,研究数值求解过程中产生的截断误差与舍入误差,以及两种误差逐层向高时间层传播的累积,得到新的数值解总误差上界的理论近似公式,以及最优格距和最优时间步长的理论公式.通过数值... 本文对于应用Lax-Friedrichs格式数值求解一维平流方程,研究数值求解过程中产生的截断误差与舍入误差,以及两种误差逐层向高时间层传播的累积,得到新的数值解总误差上界的理论近似公式,以及最优格距和最优时间步长的理论公式.通过数值算例验证了所得公式的可靠性。然后,发现了两种不同机器精度下最优时间步长之比满足的一个仅与机器精度有关的普适关系.最后,理论验证了在网格比固定的情况下,此问题满足数值计算的不确定性原理,以及在机器有限精度下最优时间步长的必然存在。 展开更多
关键词 Lax-Friedrichs格式 数值计算的不确定性原理 最优格距 最优时间步长 普适关系
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Finite-difference modeling with variable grid-size and adaptive time-step in porous media
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作者 Xinxin Liu Xingyao Yin Guochen Wu 《Earthquake Science》 2014年第2期169-178,共10页
Forward modeling of elastic wave propagation in porous media has great importance for understanding and interpreting the influences of rock properties on characteristics of seismic wavefield. However,the finite-differ... Forward modeling of elastic wave propagation in porous media has great importance for understanding and interpreting the influences of rock properties on characteristics of seismic wavefield. However,the finite-difference forward-modeling method is usually implemented with global spatial grid-size and time-step; it consumes large amounts of computational cost when small-scaled oil/gas-bearing structures or large velocity-contrast exist underground. To overcome this handicap,combined with variable grid-size and time-step,this paper developed a staggered-grid finite-difference scheme for elastic wave modeling in porous media. Variable finite-difference coefficients and wavefield interpolation were used to realize the transition of wave propagation between regions of different grid-size. The accuracy and efficiency of the algorithm were shown by numerical examples. The proposed method is advanced with low computational cost in elastic wave simulation for heterogeneous oil/gas reservoirs. 展开更多
关键词 Staggered-grid finite-difference scheme Variable grid-size Variable time-step Porous media
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Simultaneous nitrification and denitrification in step feeding biological nitrogen removal process 被引量:19
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作者 ZHU Gui-bing PENG Yong-zhen +2 位作者 WU Shu-yun WANG Shu-ying XU Shi-wei 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第9期1043-1048,共6页
The simultaneous nitrification and denitrification in step-feeding biological nitrogen removal process were investigated under different influent substrate concentrations and aeration flow rates. Biological occurrence... The simultaneous nitrification and denitrification in step-feeding biological nitrogen removal process were investigated under different influent substrate concentrations and aeration flow rates. Biological occurrence of simultaneous nitrification and denitrification was verified in the aspect of nitrogen mass balance and alkalinity. The experimental results also showed that there was a distinct linear relationship between simultaneous nitrification and denitrification and DO concentration under the conditions of low and high aeration flow rate. In each experimental run the floc sizes of activated sludge were also measured and the results showed that simultaneous nitrification and denitrification could occur with very small size of floc. 展开更多
关键词 biological nitrogen removal dissolved oxygen floc size simultaneous nitrification and denitrification step feeding process
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Effects of Two Step Calcination Process on Reaction Sintering Properties of Cordierite Materials
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作者 QIN Mengli WANG Xitang +2 位作者 WANG Zhoufu MA Yan LIU Hao 《China's Refractories》 CAS 2017年第3期49-52,共4页
Cordierite materials were mineral materials via the two synthesized using natural step calcination process. The phase composition and microstructure of the specimens were analysized by X-ray diffraction (XRD) and sc... Cordierite materials were mineral materials via the two synthesized using natural step calcination process. The phase composition and microstructure of the specimens were analysized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) , respectively. The sintering properties of cordierite materials were also characterized. The effect of two step calcination process on the reaction sintering properties of cordierite materials was investigated. The results show that the two step calcination process can significantly increase the reaction sintering properties of the cordierite materials. When the weight ratio of the presynthesized cordierite to the premixed raw mineral materials is 2 :1, the cordierite materials obtained by the two step calcination process have the higher bulk density and the lower apparent porosity (2.18 g · cm^- 3 and 13.85% , respectively). Furthermore, the addition of presynthesized cordierite clinker in the process of synthesizing cordierite materials can promote the growth of cordierite crystalline size. 展开更多
关键词 CORDIERITE two step calcination MICROSTRUCTURE crystal size
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Five Steps Block Predictor-Block Corrector Method for the Solution of <i>y''</i>= <i>f</i>(<i>x</i>,<i>y</i>,<i>y'</i>)
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作者 Mathew Remilekun Odekunle Michael Otokpa Egwurube +1 位作者 Adetola Olaide Adesanya Mfon Okon Udo 《Applied Mathematics》 2014年第8期1252-1266,共15页
Theory has it that increasing the step length improves the accuracy of a method. In order to affirm this we increased the step length of the concept in [1] by one to get k = 5. The technique of collocation and interpo... Theory has it that increasing the step length improves the accuracy of a method. In order to affirm this we increased the step length of the concept in [1] by one to get k = 5. The technique of collocation and interpolation of the power series approximate solution at some selected grid points is considered so as to generate continuous linear multistep methods with constant step sizes. Two, three and four interpolation points are considered to generate the continuous predictor-corrector methods which are implemented in block method respectively. The proposed methods when tested on some numerical examples performed more efficiently than those of [1]. Interestingly the concept of self starting [2] and that of constant order are reaffirmed in our new methods. 展开更多
关键词 step Length Power Series BLOCK PREDICTOR BLOCK CORRECTOR Constant Order step size Grid Points Self Starting Efficiency
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