Dispersion and nonlinear distortion have an effect on transmission performanc es of optic al fiber transimission systems. The schemes of dispersion compensation and nonli near distortion self-compens ation in telecom-...Dispersion and nonlinear distortion have an effect on transmission performanc es of optic al fiber transimission systems. The schemes of dispersion compensation and nonli near distortion self-compens ation in telecom-CATV co-network transmission systems are reported, followed by investigation on (1) the impact of dispersion compensation fiber (DCF) on fi ber nonlinear effects with a cascade of erbium-doped fiber amplifiers (EDFAs) an d different dispersion compensation schemes, (2) the impact of the complex on th e total nonlinear distortion induced by EDFA gain tilt and the light source. As a result , dispersion compensation optimal scheme and EDFA negative gain tilt are suggest ed as a solution to dispersion compensation and the nonlinear distortion self-c ompensation.展开更多
A lot of work has focused on compensating nonlinear distortions ofthe microspeaker under large excitation, yet it is unclear at which levelthe effect of nonlinear distortion is imperceptible or not annoying. Inthis st...A lot of work has focused on compensating nonlinear distortions ofthe microspeaker under large excitation, yet it is unclear at which levelthe effect of nonlinear distortion is imperceptible or not annoying. Inthis study virtual listening tests were performed to evaluate thedeterioration of sound quality in music signals with different levels ofnonlinear distortion by a microspeaker. Binaural recordings of themusic played by the microspeaker were made at different voltagelevels, adjusted to the same RMS power, and afterwards reproducedby a low distortion reference headphone. The “double-blind triple-stimuluswith hidden reference” method was used in the listening tests. Listenerswere required to not only discern the distortion, but also rank theseverity of the distortion. The effects of several factors includingsubject, program material and distortion level on the perceiveddistortion are discussed.展开更多
The developing populace and industrialization power demand prompted the requirement for power generation from elective sources.The desire for this pursuit is solid due to the ever-present common assets of petroleum de...The developing populace and industrialization power demand prompted the requirement for power generation from elective sources.The desire for this pursuit is solid due to the ever-present common assets of petroleum deri-vatives and their predominant ecological issues.It is generally acknowledged that sustainable power sources are one of the best answers for the energy emergency.Among these,Photovoltaic(PV)sources have many benefits to bestow a very promising future.If integrated into the existing power distribution infrastructure,the solar source will be more successful,requiring efficient Direct Current(DC)-Alternating Current(AC)conversion.This paper mainly aims to improve control-lers’performance between AC/DC Energy sources and the DC loads using the Adaptive Nonlinear Sliding Mode(ANSM)control method.The proposed ANSM method efficiently controls power quality issues,such as transient response,powerflow reliability and Total Harmonics Distortion(THD).The proposed con-troller is applied for both AC/DC and DC/DC converters and the performance of the proposed controller is validated through simulation checking the above para-meters.The simulation results confirm ANSM configuration is more reliable and efficient than the existing fuzzy and sliding mode control methods.展开更多
应变-旋转(Strain-Rotation,S-R)和分解定理为分析几何非线性问题提供了合理可靠的理论基础,但用有限元求解时会遇到大变形发生后的网格畸变问题。近年提出的虚单元法(Virtual element method,VEM)适用于一般的多边形网格,因此,该文尝...应变-旋转(Strain-Rotation,S-R)和分解定理为分析几何非线性问题提供了合理可靠的理论基础,但用有限元求解时会遇到大变形发生后的网格畸变问题。近年提出的虚单元法(Virtual element method,VEM)适用于一般的多边形网格,因此,该文尝试使用一阶虚单元求解基于S-R和分解定理的二维几何非线性问题,以克服网格畸变的影响。基于重新定义的多项式位移空间基函数,推演获得一阶虚单元分析线弹性力学问题时允许位移空间向多项式位移空间的投影表达式;按照虚单元法双线性格式的计算规则,分析处理基于更新拖带坐标法和势能率原理的增量变分方程;进而建立离散系统方程及其矩阵表达形式,并编制MATLAB求解程序;采用常规多边形网格和畸变网格,应用该文算法分析均布荷载下的悬臂梁和均匀内压下的厚壁圆筒变形。结果与已有文献和ANSYS软件的对比表明:该文算法在两种网格中均可有效执行且具备足够数值精度。总体该文算法为基于S-R和分解定理的二维几何非线性问题求解提供了一种鲁棒方法。展开更多
Due to the interdependency of frame synchronization(FS)and channel estimation(CE),joint FS and CE(JFSCE)schemes are proposed to enhance their functionalities and therefore boost the overall performance of wireless com...Due to the interdependency of frame synchronization(FS)and channel estimation(CE),joint FS and CE(JFSCE)schemes are proposed to enhance their functionalities and therefore boost the overall performance of wireless communication systems.Although traditional JFSCE schemes alleviate the influence between FS and CE,they show deficiencies in dealing with hardware imperfection(HI)and deterministic line-of-sight(LOS)path.To tackle this challenge,we proposed a cascaded ELM-based JFSCE to alleviate the influence of HI in the scenario of the Rician fading channel.Specifically,the conventional JFSCE method is first employed to extract the initial features,and thus forms the non-Neural Network(NN)solutions for FS and CE,respectively.Then,the ELMbased networks,named FS-NET and CE-NET,are cascaded to capture the NN solutions of FS and CE.Simulation and analysis results show that,compared with the conventional JFSCE methods,the proposed cascaded ELM-based JFSCE significantly reduces the error probability of FS and the normalized mean square error(NMSE)of CE,even against the impacts of parameter variations.展开更多
机场场面多点定位利用S模式信号到达时间差实现目标定位。针对S模式信号易受接收系统内部非线性影响和机场场面复杂电磁干扰的问题,研究S模式信号失真恢复方法。根据S模式信号频谱特征和接收基站弱非线性记忆系统特征简化Volterra级数,...机场场面多点定位利用S模式信号到达时间差实现目标定位。针对S模式信号易受接收系统内部非线性影响和机场场面复杂电磁干扰的问题,研究S模式信号失真恢复方法。根据S模式信号频谱特征和接收基站弱非线性记忆系统特征简化Volterra级数,降低计算量的同时满足Volterra级数关键核函数对S模式信号非线性失真表示能力,得到S模式信号失真恢复模型。仿真结果表明:3阶简化Volterra级数模型恢复15 dB和0 dB S模式信号前导脉冲的失真前波形,误差仅有2.23%和12.59%,且模型在典型运用环境下满足一定的适用性、抗干扰性和稳定性,为S模式信号到达时间戳的准确提取提供基础。展开更多
This paper proposes a novel low distortion high linearity CMOS bootstrapped switch, and the proposed switch can alleviate the nonlinear distortion of the on-resistance by eliminating first order signal-dependent varia...This paper proposes a novel low distortion high linearity CMOS bootstrapped switch, and the proposed switch can alleviate the nonlinear distortion of the on-resistance by eliminating first order signal-dependent variation of the overdrive voltage. Based on a 0.18 mm standard CMOS process, the simulation results show that at 100 MHz sampling clock frequency and 49 MHz input signal with 2Vpp, the proposed switch in differential mode has a Spurious-Free Dynamic Range(SFDR) of 90.1 dB.展开更多
The objective of the present paper is to develop nonlinear finite element method models for predicting the weld-induced initial deflection and residual stress of plating in steel stiffened-plate structures. For this p...The objective of the present paper is to develop nonlinear finite element method models for predicting the weld-induced initial deflection and residual stress of plating in steel stiffened-plate structures. For this purpose, three-dimensional thermo-elastic-plastic finite element method computations are performed with varying plate thickness and weld bead length (leg length) in welded plate panels, the latter being associated with weld heat input. The finite element models are verified by a comparison with experimental database which was obtained by the authors in separate studies with full scale measurements. It is concluded that the nonlinear finite element method models developed in the present paper are very accurate in terms of predicting the weld-induced initial imperfections of steel stiffened plate structures. Details of the numerical computations together with test database are documented.展开更多
An image distortion correction method is proposed, which uses the straight line features. Many parallel lines of different direction from different images were extracted, and then were used to optimize the distortion ...An image distortion correction method is proposed, which uses the straight line features. Many parallel lines of different direction from different images were extracted, and then were used to optimize the distortion parameters by nonlinear least square. The thought of step by step was added when the optimization method working. 3D world coordination is not need to know, and the method is easy to implement. The experiment result shows its high accuracy.展开更多
Harmonics distortion is a crucial problem in microgrid. Harmonic sources can be categorized as two main factors: renewable energy integration and nonlinear loads. Both factors are investigated in this paper. For renew...Harmonics distortion is a crucial problem in microgrid. Harmonic sources can be categorized as two main factors: renewable energy integration and nonlinear loads. Both factors are investigated in this paper. For renewbale energy, photovoltaic (PV) power is one of the most effective solutions for energy crisis and it is showing great potential for serving customers in microgrid. A three- phase PV source model is establised and integrated at different locations in order to observe the impact of harmonics on a microgrid and power quality (PQ). A composite load is modeled using Crossed Frequency Admittance Matrix theory. A practicdal microgrid loacated at GA, USA is used as a study system. The microgrid, PV model and nonlinear load model are simulated in MATLAB/ Simulink environment. The results show the impact of installing PV sources at two types of locations considering linear and composite nonlinear loads. In addition, three PQ indices are discussed to show the numerical impacts with various perspectives.展开更多
文摘Dispersion and nonlinear distortion have an effect on transmission performanc es of optic al fiber transimission systems. The schemes of dispersion compensation and nonli near distortion self-compens ation in telecom-CATV co-network transmission systems are reported, followed by investigation on (1) the impact of dispersion compensation fiber (DCF) on fi ber nonlinear effects with a cascade of erbium-doped fiber amplifiers (EDFAs) an d different dispersion compensation schemes, (2) the impact of the complex on th e total nonlinear distortion induced by EDFA gain tilt and the light source. As a result , dispersion compensation optimal scheme and EDFA negative gain tilt are suggest ed as a solution to dispersion compensation and the nonlinear distortion self-c ompensation.
文摘A lot of work has focused on compensating nonlinear distortions ofthe microspeaker under large excitation, yet it is unclear at which levelthe effect of nonlinear distortion is imperceptible or not annoying. Inthis study virtual listening tests were performed to evaluate thedeterioration of sound quality in music signals with different levels ofnonlinear distortion by a microspeaker. Binaural recordings of themusic played by the microspeaker were made at different voltagelevels, adjusted to the same RMS power, and afterwards reproducedby a low distortion reference headphone. The “double-blind triple-stimuluswith hidden reference” method was used in the listening tests. Listenerswere required to not only discern the distortion, but also rank theseverity of the distortion. The effects of several factors includingsubject, program material and distortion level on the perceiveddistortion are discussed.
文摘The developing populace and industrialization power demand prompted the requirement for power generation from elective sources.The desire for this pursuit is solid due to the ever-present common assets of petroleum deri-vatives and their predominant ecological issues.It is generally acknowledged that sustainable power sources are one of the best answers for the energy emergency.Among these,Photovoltaic(PV)sources have many benefits to bestow a very promising future.If integrated into the existing power distribution infrastructure,the solar source will be more successful,requiring efficient Direct Current(DC)-Alternating Current(AC)conversion.This paper mainly aims to improve control-lers’performance between AC/DC Energy sources and the DC loads using the Adaptive Nonlinear Sliding Mode(ANSM)control method.The proposed ANSM method efficiently controls power quality issues,such as transient response,powerflow reliability and Total Harmonics Distortion(THD).The proposed con-troller is applied for both AC/DC and DC/DC converters and the performance of the proposed controller is validated through simulation checking the above para-meters.The simulation results confirm ANSM configuration is more reliable and efficient than the existing fuzzy and sliding mode control methods.
文摘应变-旋转(Strain-Rotation,S-R)和分解定理为分析几何非线性问题提供了合理可靠的理论基础,但用有限元求解时会遇到大变形发生后的网格畸变问题。近年提出的虚单元法(Virtual element method,VEM)适用于一般的多边形网格,因此,该文尝试使用一阶虚单元求解基于S-R和分解定理的二维几何非线性问题,以克服网格畸变的影响。基于重新定义的多项式位移空间基函数,推演获得一阶虚单元分析线弹性力学问题时允许位移空间向多项式位移空间的投影表达式;按照虚单元法双线性格式的计算规则,分析处理基于更新拖带坐标法和势能率原理的增量变分方程;进而建立离散系统方程及其矩阵表达形式,并编制MATLAB求解程序;采用常规多边形网格和畸变网格,应用该文算法分析均布荷载下的悬臂梁和均匀内压下的厚壁圆筒变形。结果与已有文献和ANSYS软件的对比表明:该文算法在两种网格中均可有效执行且具备足够数值精度。总体该文算法为基于S-R和分解定理的二维几何非线性问题求解提供了一种鲁棒方法。
基金supported in part by the Sichuan Science and Technology Program(Grant No.2023YFG0316)the Industry-University Research Innovation Fund of China University(Grant No.2021ITA10016)+1 种基金the Key Scientific Research Fund of Xihua University(Grant No.Z1320929)the Special Funds of Industry Development of Sichuan Province(Grant No.zyf-2018-056).
文摘Due to the interdependency of frame synchronization(FS)and channel estimation(CE),joint FS and CE(JFSCE)schemes are proposed to enhance their functionalities and therefore boost the overall performance of wireless communication systems.Although traditional JFSCE schemes alleviate the influence between FS and CE,they show deficiencies in dealing with hardware imperfection(HI)and deterministic line-of-sight(LOS)path.To tackle this challenge,we proposed a cascaded ELM-based JFSCE to alleviate the influence of HI in the scenario of the Rician fading channel.Specifically,the conventional JFSCE method is first employed to extract the initial features,and thus forms the non-Neural Network(NN)solutions for FS and CE,respectively.Then,the ELMbased networks,named FS-NET and CE-NET,are cascaded to capture the NN solutions of FS and CE.Simulation and analysis results show that,compared with the conventional JFSCE methods,the proposed cascaded ELM-based JFSCE significantly reduces the error probability of FS and the normalized mean square error(NMSE)of CE,even against the impacts of parameter variations.
文摘机场场面多点定位利用S模式信号到达时间差实现目标定位。针对S模式信号易受接收系统内部非线性影响和机场场面复杂电磁干扰的问题,研究S模式信号失真恢复方法。根据S模式信号频谱特征和接收基站弱非线性记忆系统特征简化Volterra级数,降低计算量的同时满足Volterra级数关键核函数对S模式信号非线性失真表示能力,得到S模式信号失真恢复模型。仿真结果表明:3阶简化Volterra级数模型恢复15 dB和0 dB S模式信号前导脉冲的失真前波形,误差仅有2.23%和12.59%,且模型在典型运用环境下满足一定的适用性、抗干扰性和稳定性,为S模式信号到达时间戳的准确提取提供基础。
基金Supported by the National Natural Science Foundation of China(Grant No.61404043)Doctoral Program Foundation of Institutions of Higher Education of China(No.201201111-20008)Key Laboratory of Infrared Imaging Materials and Detectors,Shanghai Institute of Technical Physics,Chinese Academy of Sciences(No.IIMDKFJJ-13-06)
文摘This paper proposes a novel low distortion high linearity CMOS bootstrapped switch, and the proposed switch can alleviate the nonlinear distortion of the on-resistance by eliminating first order signal-dependent variation of the overdrive voltage. Based on a 0.18 mm standard CMOS process, the simulation results show that at 100 MHz sampling clock frequency and 49 MHz input signal with 2Vpp, the proposed switch in differential mode has a Spurious-Free Dynamic Range(SFDR) of 90.1 dB.
文摘The objective of the present paper is to develop nonlinear finite element method models for predicting the weld-induced initial deflection and residual stress of plating in steel stiffened-plate structures. For this purpose, three-dimensional thermo-elastic-plastic finite element method computations are performed with varying plate thickness and weld bead length (leg length) in welded plate panels, the latter being associated with weld heat input. The finite element models are verified by a comparison with experimental database which was obtained by the authors in separate studies with full scale measurements. It is concluded that the nonlinear finite element method models developed in the present paper are very accurate in terms of predicting the weld-induced initial imperfections of steel stiffened plate structures. Details of the numerical computations together with test database are documented.
文摘An image distortion correction method is proposed, which uses the straight line features. Many parallel lines of different direction from different images were extracted, and then were used to optimize the distortion parameters by nonlinear least square. The thought of step by step was added when the optimization method working. 3D world coordination is not need to know, and the method is easy to implement. The experiment result shows its high accuracy.
文摘Harmonics distortion is a crucial problem in microgrid. Harmonic sources can be categorized as two main factors: renewable energy integration and nonlinear loads. Both factors are investigated in this paper. For renewbale energy, photovoltaic (PV) power is one of the most effective solutions for energy crisis and it is showing great potential for serving customers in microgrid. A three- phase PV source model is establised and integrated at different locations in order to observe the impact of harmonics on a microgrid and power quality (PQ). A composite load is modeled using Crossed Frequency Admittance Matrix theory. A practicdal microgrid loacated at GA, USA is used as a study system. The microgrid, PV model and nonlinear load model are simulated in MATLAB/ Simulink environment. The results show the impact of installing PV sources at two types of locations considering linear and composite nonlinear loads. In addition, three PQ indices are discussed to show the numerical impacts with various perspectives.