This paper investigates the numerical solution of two-dimensional nonlinear stochastic Itô-Volterra integral equations based on block pulse functions. The nonlinear stochastic integral equation is transformed...This paper investigates the numerical solution of two-dimensional nonlinear stochastic Itô-Volterra integral equations based on block pulse functions. The nonlinear stochastic integral equation is transformed into a set of algebraic equations by operational matrix of block pulse functions. Then, we give error analysis and prove that the rate of convergence of this method is efficient. Lastly, a numerical example is given to confirm the method.展开更多
One function for approximating pulse quantities in high voltage technique is presented in this paper. The function derivative, its integral, as well as its Laplace and Fourier transform are obtained analytically. Inte...One function for approximating pulse quantities in high voltage technique is presented in this paper. The function derivative, its integral, as well as its Laplace and Fourier transform are obtained analytically. Integral transformations of the pulse function are needed in frequency domain calculations of lightning induced effects in the case of a lossy ground. The pulse function having adequately chosen parameters is applied in lightning discharge modeling for lightning electromagnetic field calculation, and the results are in agreement with the results from literature. The choice of function parameters is based on their influence on the pulse waveshape which is presented in the paper. Numerical results for the Fourier transform are presented for different usually used pulse functions. The advantages of this function are simple choice of its parameters according to the desired waveshape characteristics and analytical solutions useful in lightning discharge modeling, electromagnetic field computation and induced effects calculations.展开更多
The development of an in-house computer program for determining the motions and loads of advancing ships through sea waves in the frequency domain,is described in this paper.The code is based on the potential flow for...The development of an in-house computer program for determining the motions and loads of advancing ships through sea waves in the frequency domain,is described in this paper.The code is based on the potential flow formulation and originates from a double-body code enhanced with the regular part of the velocity potential computed using the pulsing source Green function.The code is fully developed in C++language with extensive use of the object-oriented paradigm.The code is capable of estimating the excitation and inertial radiation loads or arbitrary incoming wave frequencies and incidence angles.The hydrodynamic responses such as hydrodynamic coefficients,ship motions,the vertical shear force and the vertical bending moment are estimated.A benchmark container ship and an LNG carrier are selected for testing and validating the computer code.The obtained results are compared with the available experimental data which demonstrate the acceptable compliance for the zero speed whereas there are some discrepancies over the range of frequencies for the advancing ship in different heading angles.展开更多
This paper explores model order reduction(MOR)methods for discrete linear and discrete bilinear systems via discrete pulse orthogonal functions(DPOFs).Firstly,the discrete linear systems and the discrete bilinear syst...This paper explores model order reduction(MOR)methods for discrete linear and discrete bilinear systems via discrete pulse orthogonal functions(DPOFs).Firstly,the discrete linear systems and the discrete bilinear systems are expanded in the space spanned by DPOFs,and two recurrence formulas for the expansion coefficients of the system’s state variables are obtained.Then,a modified Arnoldi process is applied to both recurrence formulas to construct the orthogonal projection matrices,by which the reduced-order systems are obtained.Theoretical analysis shows that the output variables of the reducedorder systems can match a certain number of the expansion coefficients of the original system’s output variables.Finally,two numerical examples illustrate the feasibility and effectiveness of the proposed methods.展开更多
We use relevant economic and labor force data from 1990 to 2009 of Henan Province to analyze the dynamic relation between stock of rural human capital and farmers' income.Results indicate that a certain causal rel...We use relevant economic and labor force data from 1990 to 2009 of Henan Province to analyze the dynamic relation between stock of rural human capital and farmers' income.Results indicate that a certain causal relationship and long-run equilibrium relation exist between rural human capital and farmers' income,but their interaction shows some lagging characteristic.Increase of farmers' income in Henan Province increases the stock of rural human capital in this province for a short term.However,in the long run,this accumulation effect will decline along with renewal and aging of knowledge.The positive promotion action of rural human capital on farmers' income will appear after a long lag time.Therefore,the policy of strengthening rural human capital input should be long-term and continuous.展开更多
This paper addresses a digital controller for a real time magnetic levitation system using series expansion of pulse transfer function, which achieves desired closed loop response. The proposed digital controller desi...This paper addresses a digital controller for a real time magnetic levitation system using series expansion of pulse transfer function, which achieves desired closed loop response. The proposed digital controller designed, based on series expansion of pulse transfer function by solving a linear equation using the method of least squares, which improves the transient performance and step tracking capability of the compensated system. The designed algorithm used for the control input is not iterative, so the calculation is very fast. The proposed control scheme has successfully applied on maglev system and also validated through the simulation and hardware experimental results.展开更多
This paper presents a new approach to singular system analysis by modeling the system in terms of orthog- onal triangular functions （TFs）. The proposed method is more accurate compared to block pulse function-based ...This paper presents a new approach to singular system analysis by modeling the system in terms of orthog- onal triangular functions （TFs）. The proposed method is more accurate compared to block pulse function-based analysis with respect to mean integral square error （MISE）. A numerical example involving four states of a singular system is treated and solutions obtained thereof. Four tables and relevant curves are presented to compare the respective coefficients in block pulse function （BPF） domain as well as in TF domain. The percentage error of the samples determined via TF domain are compared with the exact samples of the states. Furthermore, MISE for both BPF and TF analysis are computed and compared to reveal the efficiency of TF-based analysis.展开更多
基金NSF Grants 11471105 of China, NSF Grants 2016CFB526 of Hubei Province, Innovation Team of the Educational Department of Hubei Province T201412, and Innovation Items of Hubei Normal University 2018032 and 2018105
文摘This paper investigates the numerical solution of two-dimensional nonlinear stochastic Itô-Volterra integral equations based on block pulse functions. The nonlinear stochastic integral equation is transformed into a set of algebraic equations by operational matrix of block pulse functions. Then, we give error analysis and prove that the rate of convergence of this method is efficient. Lastly, a numerical example is given to confirm the method.
文摘One function for approximating pulse quantities in high voltage technique is presented in this paper. The function derivative, its integral, as well as its Laplace and Fourier transform are obtained analytically. Integral transformations of the pulse function are needed in frequency domain calculations of lightning induced effects in the case of a lossy ground. The pulse function having adequately chosen parameters is applied in lightning discharge modeling for lightning electromagnetic field calculation, and the results are in agreement with the results from literature. The choice of function parameters is based on their influence on the pulse waveshape which is presented in the paper. Numerical results for the Fourier transform are presented for different usually used pulse functions. The advantages of this function are simple choice of its parameters according to the desired waveshape characteristics and analytical solutions useful in lightning discharge modeling, electromagnetic field computation and induced effects calculations.
文摘The development of an in-house computer program for determining the motions and loads of advancing ships through sea waves in the frequency domain,is described in this paper.The code is based on the potential flow formulation and originates from a double-body code enhanced with the regular part of the velocity potential computed using the pulsing source Green function.The code is fully developed in C++language with extensive use of the object-oriented paradigm.The code is capable of estimating the excitation and inertial radiation loads or arbitrary incoming wave frequencies and incidence angles.The hydrodynamic responses such as hydrodynamic coefficients,ship motions,the vertical shear force and the vertical bending moment are estimated.A benchmark container ship and an LNG carrier are selected for testing and validating the computer code.The obtained results are compared with the available experimental data which demonstrate the acceptable compliance for the zero speed whereas there are some discrepancies over the range of frequencies for the advancing ship in different heading angles.
基金supported by Natural Science Foundation of Xinjiang Uygur Autonomous Region of China“Research on model order reduction methods based on the discrete orthogonal polynomials”(2023D01C163)The Tianchi Talent Introduction Plan Project of Xinjiang Uygur Autonomous Region of China“Research on orthogonal decomposition model order reduction methods for discrete control systems”.
文摘This paper explores model order reduction(MOR)methods for discrete linear and discrete bilinear systems via discrete pulse orthogonal functions(DPOFs).Firstly,the discrete linear systems and the discrete bilinear systems are expanded in the space spanned by DPOFs,and two recurrence formulas for the expansion coefficients of the system’s state variables are obtained.Then,a modified Arnoldi process is applied to both recurrence formulas to construct the orthogonal projection matrices,by which the reduced-order systems are obtained.Theoretical analysis shows that the output variables of the reducedorder systems can match a certain number of the expansion coefficients of the original system’s output variables.Finally,two numerical examples illustrate the feasibility and effectiveness of the proposed methods.
文摘We use relevant economic and labor force data from 1990 to 2009 of Henan Province to analyze the dynamic relation between stock of rural human capital and farmers' income.Results indicate that a certain causal relationship and long-run equilibrium relation exist between rural human capital and farmers' income,but their interaction shows some lagging characteristic.Increase of farmers' income in Henan Province increases the stock of rural human capital in this province for a short term.However,in the long run,this accumulation effect will decline along with renewal and aging of knowledge.The positive promotion action of rural human capital on farmers' income will appear after a long lag time.Therefore,the policy of strengthening rural human capital input should be long-term and continuous.
文摘This paper addresses a digital controller for a real time magnetic levitation system using series expansion of pulse transfer function, which achieves desired closed loop response. The proposed digital controller designed, based on series expansion of pulse transfer function by solving a linear equation using the method of least squares, which improves the transient performance and step tracking capability of the compensated system. The designed algorithm used for the control input is not iterative, so the calculation is very fast. The proposed control scheme has successfully applied on maglev system and also validated through the simulation and hardware experimental results.
文摘This paper presents a new approach to singular system analysis by modeling the system in terms of orthog- onal triangular functions （TFs）. The proposed method is more accurate compared to block pulse function-based analysis with respect to mean integral square error （MISE）. A numerical example involving four states of a singular system is treated and solutions obtained thereof. Four tables and relevant curves are presented to compare the respective coefficients in block pulse function （BPF） domain as well as in TF domain. The percentage error of the samples determined via TF domain are compared with the exact samples of the states. Furthermore, MISE for both BPF and TF analysis are computed and compared to reveal the efficiency of TF-based analysis.
