Based on the conception of perturbation, an approach to the interval Bezier surfaces approximating ra- tional surfaces is presented using the energy minimization method. The method places more restrictions on the pert...Based on the conception of perturbation, an approach to the interval Bezier surfaces approximating ra- tional surfaces is presented using the energy minimization method. The method places more restrictions on the perturbation surfaces than the original surfaces. The applications of the approach are also presented. Experimen- tal result is combined with the subdivision method to obtain a piecewise interval polynomial approximation for a rational surface.展开更多
The support vector machine （SVM） is a novel machine learning method, which has the ability to approximate nonlinear functions with arbitrary accuracy. Setting parameters well is very crucial for SVM learning results...The support vector machine （SVM） is a novel machine learning method, which has the ability to approximate nonlinear functions with arbitrary accuracy. Setting parameters well is very crucial for SVM learning results and generalization ability, and now there is no systematic, general method for parameter selection. In this article, the SVM parameter selection for function approximation is regarded as a compound optimization problem and a mutative scale chaos optimization algorithm is employed to search for optimal paraxneter values. The chaos optimization algorithm is an effective way for global optimal and the mutative scale chaos algorithm could improve the search efficiency and accuracy. Several simulation examples show the sensitivity of the SVM parameters and demonstrate the superiority of this proposed method for nonlinear function approximation.展开更多
A theory of elasticity for the bending of orthogonal anisotropic beams was developed in this paper by analogy with the special case, which can be obtained by applying the theory of elasticity for bending of transverse...A theory of elasticity for the bending of orthogonal anisotropic beams was developed in this paper by analogy with the special case, which can be obtained by applying the theory of elasticity for bending of transversely isotropic plates to the problems of two dimensions. The authors also presented a method to solve the problems of bending of orthogonal anisotropic beams and a new theory of the deep-beam whose ratio of depth to length is larger. It is pointed out that Reissner's theory which takes into account the effect of transverse shear deformation is not suitable for the components of stress in our case.展开更多
In order to solve three kinds of fuzzy programm model, fuzzy chance-constrained programming mode ng models, i.e. fuzzy expected value and fuzzy dependent-chance programming model, a simultaneous perturbation stochast...In order to solve three kinds of fuzzy programm model, fuzzy chance-constrained programming mode ng models, i.e. fuzzy expected value and fuzzy dependent-chance programming model, a simultaneous perturbation stochastic approximation algorithm is proposed by integrating neural network with fuzzy simulation. At first, fuzzy simulation is used to generate a set of input-output data. Then a neural network is trained according to the set. Finally, the trained neural network is embedded in simultaneous perturbation stochastic approximation algorithm. Simultaneous perturbation stochastic approximation algorithm is used to search the optimal solution. Two numerical examples are presented to illustrate the effectiveness of the proposed algorithm.展开更多
Approximate dynamic programming (ADP) is a general and effective approach for solving optimal control and estimation problems by adapting to uncertain and nonconvex environments over time.
On the basis of analyzing the principle of multicarrier code division multiple access (MC-CDMA), an optimized complex wavelet packet based MC-CDMA system (CWP-MC-CDMA) is proposed. The system performances with equal g...On the basis of analyzing the principle of multicarrier code division multiple access (MC-CDMA), an optimized complex wavelet packet based MC-CDMA system (CWP-MC-CDMA) is proposed. The system performances with equal gain combining (EGC) technique and maximum ratio combining (MRC) technique in Nakagami-m fading channels are investigated, respectively; and the corresponding bit error rate (BER) expression is derived. The system can overcome the decrease of spectrum efficiency of discrete Fourier transform (DFT) based conventional MC-CDMA (DFT-MC-CDMA) due to inserting a cyclic prefix (CP). Theoretical analysis and simulation results show that the CWP-MC-CDMA system outperforms DFT-MC-CDMA as well as the real wavelet packet based MC-CDMA (RWP-MC-CDMA) system, and has superior ability to combat multi-path fading and multi-access interference (MAI). Moreover, the BER performance of the proposed system is also superior to that of the conventional MC-CDMA with CP.展开更多
Algebraic methods and rapid deforming techniques are used to generate three-dimensional boundary-fitted dynamic grids for assemblies. The conservative full-potential equation is solved by a time-accurate approximate f...Algebraic methods and rapid deforming techniques are used to generate three-dimensional boundary-fitted dynamic grids for assemblies. The conservative full-potential equation is solved by a time-accurate approximate factorization algorithm and internal Newton iterations. An integral boundary layer method based on the dissipation integral is used to account for viscous effects. The computational results about unsteady transonic forces on wings, bodies and control surfaces are in agreement with experimental data.展开更多
An approximate method is presented to investigate the earthquake response of the fluid-single leg (shortened for S. L.) gravity platform-soil interaction system. By assuming a suitable form of the velocity potential o...An approximate method is presented to investigate the earthquake response of the fluid-single leg (shortened for S. L.) gravity platform-soil interaction system. By assuming a suitable form of the velocity potential of the radiation waves and by using the motion equation and the boundary conditions, the unknown coefficients can be obtained. Thereafter the function of frequency for the interaction system may also be obtained. In this paper, the difference of the system dynamic response between rigid foundation is analyzed and the influences of the various foundation geometric dimension and the various water-depth on the hydrodynamic loading and dynamic response of the system is illustrated.展开更多
An initially periodic motion is gradually raised out of the potential well by the effect of negative damping. The elapsed time when the motion ceases to be periodic is obtained by multiple variable expansions. An exam...An initially periodic motion is gradually raised out of the potential well by the effect of negative damping. The elapsed time when the motion ceases to be periodic is obtained by multiple variable expansions. An example of a strictly nonlinear system shows the result has a good approximation and is easy to calculate.展开更多
In this paper, the exact Bayesian limits, taking conjugate and noninformative prior distribution, and the exact fiducial limits for the mean of the lognormal distribution are presented. They can be found iteratively b...In this paper, the exact Bayesian limits, taking conjugate and noninformative prior distribution, and the exact fiducial limits for the mean of the lognormal distribution are presented. They can be found iteratively by one-dimension integral on a finite interval. The new algorithm is very convenient and with high accuracy. It can meet the practical engineering need excellently. However, the primitive algorithm is rather cumbersome. By the way, the very close approximate limits with a simple algorithm are derived. They can be applied immediately to engineering. Otherwise, they can also be used as a search interval to find the root of equation for the exact limits.展开更多
A detailed fracture mechanics analysis of bridge-toughening in a fiber reinforced composite is presented in this paper. The integral equation governing bridge-toughening as well as crack opening displacement (COD) for...A detailed fracture mechanics analysis of bridge-toughening in a fiber reinforced composite is presented in this paper. The integral equation governing bridge-toughening as well as crack opening displacement (COD) for the composite with interfacial layer is derived from the Castigliano's theorem and interface shear-lag model. A numerical result of the COD equation is obtained using the iteration solution of the second Fredholm integral equation. In order to investigate the effect of various parameters on the toughening, an approximate analytical solution of the equation is present and its error analysis is performed, which demonstrates the approximate solution to be appropriate. A parametric study of the influence of the crack length, interfacial shear modules, thickness of the interphase, fiber radius, fiber volume fraction and properties of materials on composite toughening is therefore carried out. The results are useful for experimental demonstration and toughening design including the fabrication process of the composite.展开更多
In this paper, a theoretical model of multi-level, non-spherical scatterers is developed for fully polarimetric scattering from tree canopy in SAR imaging at C band. The amplitude functions of non-spherical particles ...In this paper, a theoretical model of multi-level, non-spherical scatterers is developed for fully polarimetric scattering from tree canopy in SAR imaging at C band. The amplitude functions of non-spherical particles with randomly spatial orientation are derived by the generalized Rayleigh-Gans (GRG) approximation. The non-diagonal extinction matrix and the Mueller matrix solution are constructed. Numerical solutions of polarimetric scattering of four Stokes parameters from random, non-spherical scatterers are obtained. To physically identify polarimetric scattering of the Mueller matrix solution, the coherency matrix and its eigen-analysis are discussed. Functional dependence of the coherency matrix and entropy upon various parameters are obtained. As an application, the analysis of AirSAR images at P, L, C bands is discussed.展开更多
The incompatible numerical manifold method （INMM） is based on the finite cover approximation theory, which provides a unified framework for problems dealing with continuum and discontinuities. The incompatible numer...The incompatible numerical manifold method （INMM） is based on the finite cover approximation theory, which provides a unified framework for problems dealing with continuum and discontinuities. The incompatible numerical manifold method employs two cover systems as follows. The mathematical cover system provides the nodes for forming finite covers of the solution domain and the weighted functions, and the physical cover system describes geometry of the domain and the discontinuous surfaces therein. In INMM, the mathematical finite cover approximation theory is used to model cracks that lead to interior discontinuities in the process of displacement. Therefore, the discontinuity is treated mathematically instead of empirically by the existing methods. However, one cover of a node is divided into two irregular sub-covers when the INMM is used to model the discontinuity. As a result, the method sometimes causes numerical errors at the tip of a crack. To improve the precision of the INMM, the analytical solution is used at the tip of a crack, and thus the cover displacement functions are extended with higher precision and computational efficiency. Some numerical examples are given.展开更多
Wavelet has been used as a powerful tool in the signal processing and function approximation recently. This paper presents the application of wavelets for solving two key problems in 3-D audio simulation. First, we em...Wavelet has been used as a powerful tool in the signal processing and function approximation recently. This paper presents the application of wavelets for solving two key problems in 3-D audio simulation. First, we employ discrete wavelet transform (DWT) combined with vector quantization (VQ) to compress audio data in order to reduce tremendous redundant data storage and transmission times. Secondly, we use wavelets as the activation functions in neural networks called feed-forward wavelet networks to approach auditory localization information cues (head-related transfer functions (HRTFs) are used here). The experimental results demonstrate that the application of wavelets is more efficient and useful in 3-D audio simulation.展开更多
When the organic vapors absorbed to the surface of porous silicon(PS), capillary condensation takes place due to the porous structure of the PS layer, accordingly resulting in the effective refractive index changing. ...When the organic vapors absorbed to the surface of porous silicon(PS), capillary condensation takes place due to the porous structure of the PS layer, accordingly resulting in the effective refractive index changing. For PS multi-layer microcavities, the different resonant peaks shift in the reflectivity spectrum of porous silicon microcavities(PSMs). The optical sensing model is set up by applying Bruggeman effective medium approximation theory, capillary condensation process and transfer matrix theoretically analytical method of one-dimensional photonic crystals. At the same time, comprehensively researched on are the sensing characteristics of PSMs which are exposed to give concentration organic vapors. At last, made is the theoretical simulation for sensing model of the PSMs in case of saturation by using computer numerical calculation, and found is the linearity relation between the refractive index of organic solvent and the peak-shift. At the same time deduced is the peak-shift as a function of the concentration of ethanol vapors.展开更多
We revisit Auslander-Buchweitz approximation theory and find some relations with cotorsion pairs and model category structures.From the notion of weak-cogenerators,we introduce the concept of Frobenius pair(X,ω)in a ...We revisit Auslander-Buchweitz approximation theory and find some relations with cotorsion pairs and model category structures.From the notion of weak-cogenerators,we introduce the concept of Frobenius pair(X,ω)in a triangulated category T.We show how to construct from a Frobenius pair(X,ω)a triangulated model structure on X^(∧).展开更多
基金Supported by the Foundation of Inner Mongolia University of Technology(X200829)~~
文摘Based on the conception of perturbation, an approach to the interval Bezier surfaces approximating ra- tional surfaces is presented using the energy minimization method. The method places more restrictions on the perturbation surfaces than the original surfaces. The applications of the approach are also presented. Experimen- tal result is combined with the subdivision method to obtain a piecewise interval polynomial approximation for a rational surface.
基金the National Nature Science Foundation of China (60775047, 60402024)
文摘The support vector machine （SVM） is a novel machine learning method, which has the ability to approximate nonlinear functions with arbitrary accuracy. Setting parameters well is very crucial for SVM learning results and generalization ability, and now there is no systematic, general method for parameter selection. In this article, the SVM parameter selection for function approximation is regarded as a compound optimization problem and a mutative scale chaos optimization algorithm is employed to search for optimal paraxneter values. The chaos optimization algorithm is an effective way for global optimal and the mutative scale chaos algorithm could improve the search efficiency and accuracy. Several simulation examples show the sensitivity of the SVM parameters and demonstrate the superiority of this proposed method for nonlinear function approximation.
文摘A theory of elasticity for the bending of orthogonal anisotropic beams was developed in this paper by analogy with the special case, which can be obtained by applying the theory of elasticity for bending of transversely isotropic plates to the problems of two dimensions. The authors also presented a method to solve the problems of bending of orthogonal anisotropic beams and a new theory of the deep-beam whose ratio of depth to length is larger. It is pointed out that Reissner's theory which takes into account the effect of transverse shear deformation is not suitable for the components of stress in our case.
基金National Natural Science Foundation of China (No.70471049)China Postdoctoral Science Foundation (No. 20060400704)
文摘In order to solve three kinds of fuzzy programm model, fuzzy chance-constrained programming mode ng models, i.e. fuzzy expected value and fuzzy dependent-chance programming model, a simultaneous perturbation stochastic approximation algorithm is proposed by integrating neural network with fuzzy simulation. At first, fuzzy simulation is used to generate a set of input-output data. Then a neural network is trained according to the set. Finally, the trained neural network is embedded in simultaneous perturbation stochastic approximation algorithm. Simultaneous perturbation stochastic approximation algorithm is used to search the optimal solution. Two numerical examples are presented to illustrate the effectiveness of the proposed algorithm.
文摘Approximate dynamic programming (ADP) is a general and effective approach for solving optimal control and estimation problems by adapting to uncertain and nonconvex environments over time.
文摘On the basis of analyzing the principle of multicarrier code division multiple access (MC-CDMA), an optimized complex wavelet packet based MC-CDMA system (CWP-MC-CDMA) is proposed. The system performances with equal gain combining (EGC) technique and maximum ratio combining (MRC) technique in Nakagami-m fading channels are investigated, respectively; and the corresponding bit error rate (BER) expression is derived. The system can overcome the decrease of spectrum efficiency of discrete Fourier transform (DFT) based conventional MC-CDMA (DFT-MC-CDMA) due to inserting a cyclic prefix (CP). Theoretical analysis and simulation results show that the CWP-MC-CDMA system outperforms DFT-MC-CDMA as well as the real wavelet packet based MC-CDMA (RWP-MC-CDMA) system, and has superior ability to combat multi-path fading and multi-access interference (MAI). Moreover, the BER performance of the proposed system is also superior to that of the conventional MC-CDMA with CP.
基金Aeronautical Science Foundation of China (99A52007)
文摘Algebraic methods and rapid deforming techniques are used to generate three-dimensional boundary-fitted dynamic grids for assemblies. The conservative full-potential equation is solved by a time-accurate approximate factorization algorithm and internal Newton iterations. An integral boundary layer method based on the dissipation integral is used to account for viscous effects. The computational results about unsteady transonic forces on wings, bodies and control surfaces are in agreement with experimental data.
基金This project is financially supported by the National Natural Science Foundation of China
文摘An approximate method is presented to investigate the earthquake response of the fluid-single leg (shortened for S. L.) gravity platform-soil interaction system. By assuming a suitable form of the velocity potential of the radiation waves and by using the motion equation and the boundary conditions, the unknown coefficients can be obtained. Thereafter the function of frequency for the interaction system may also be obtained. In this paper, the difference of the system dynamic response between rigid foundation is analyzed and the influences of the various foundation geometric dimension and the various water-depth on the hydrodynamic loading and dynamic response of the system is illustrated.
文摘An initially periodic motion is gradually raised out of the potential well by the effect of negative damping. The elapsed time when the motion ceases to be periodic is obtained by multiple variable expansions. An example of a strictly nonlinear system shows the result has a good approximation and is easy to calculate.
文摘In this paper, the exact Bayesian limits, taking conjugate and noninformative prior distribution, and the exact fiducial limits for the mean of the lognormal distribution are presented. They can be found iteratively by one-dimension integral on a finite interval. The new algorithm is very convenient and with high accuracy. It can meet the practical engineering need excellently. However, the primitive algorithm is rather cumbersome. By the way, the very close approximate limits with a simple algorithm are derived. They can be applied immediately to engineering. Otherwise, they can also be used as a search interval to find the root of equation for the exact limits.
基金National Natural Science Foundatjon and China Postdoctoral Scjence Fbundation
文摘A detailed fracture mechanics analysis of bridge-toughening in a fiber reinforced composite is presented in this paper. The integral equation governing bridge-toughening as well as crack opening displacement (COD) for the composite with interfacial layer is derived from the Castigliano's theorem and interface shear-lag model. A numerical result of the COD equation is obtained using the iteration solution of the second Fredholm integral equation. In order to investigate the effect of various parameters on the toughening, an approximate analytical solution of the equation is present and its error analysis is performed, which demonstrates the approximate solution to be appropriate. A parametric study of the influence of the crack length, interfacial shear modules, thickness of the interphase, fiber radius, fiber volume fraction and properties of materials on composite toughening is therefore carried out. The results are useful for experimental demonstration and toughening design including the fabrication process of the composite.
文摘In this paper, a theoretical model of multi-level, non-spherical scatterers is developed for fully polarimetric scattering from tree canopy in SAR imaging at C band. The amplitude functions of non-spherical particles with randomly spatial orientation are derived by the generalized Rayleigh-Gans (GRG) approximation. The non-diagonal extinction matrix and the Mueller matrix solution are constructed. Numerical solutions of polarimetric scattering of four Stokes parameters from random, non-spherical scatterers are obtained. To physically identify polarimetric scattering of the Mueller matrix solution, the coherency matrix and its eigen-analysis are discussed. Functional dependence of the coherency matrix and entropy upon various parameters are obtained. As an application, the analysis of AirSAR images at P, L, C bands is discussed.
基金supported by the Natural Science Foundation of Shandong Province for Excellent Young and Middle-aged Scientist (2007BS04045 and 2008BS04009)the Natural Science Foundation of Shandong Province(Y2006B24 and Y2008A 11)
文摘The incompatible numerical manifold method （INMM） is based on the finite cover approximation theory, which provides a unified framework for problems dealing with continuum and discontinuities. The incompatible numerical manifold method employs two cover systems as follows. The mathematical cover system provides the nodes for forming finite covers of the solution domain and the weighted functions, and the physical cover system describes geometry of the domain and the discontinuous surfaces therein. In INMM, the mathematical finite cover approximation theory is used to model cracks that lead to interior discontinuities in the process of displacement. Therefore, the discontinuity is treated mathematically instead of empirically by the existing methods. However, one cover of a node is divided into two irregular sub-covers when the INMM is used to model the discontinuity. As a result, the method sometimes causes numerical errors at the tip of a crack. To improve the precision of the INMM, the analytical solution is used at the tip of a crack, and thus the cover displacement functions are extended with higher precision and computational efficiency. Some numerical examples are given.
文摘Wavelet has been used as a powerful tool in the signal processing and function approximation recently. This paper presents the application of wavelets for solving two key problems in 3-D audio simulation. First, we employ discrete wavelet transform (DWT) combined with vector quantization (VQ) to compress audio data in order to reduce tremendous redundant data storage and transmission times. Secondly, we use wavelets as the activation functions in neural networks called feed-forward wavelet networks to approach auditory localization information cues (head-related transfer functions (HRTFs) are used here). The experimental results demonstrate that the application of wavelets is more efficient and useful in 3-D audio simulation.
文摘When the organic vapors absorbed to the surface of porous silicon(PS), capillary condensation takes place due to the porous structure of the PS layer, accordingly resulting in the effective refractive index changing. For PS multi-layer microcavities, the different resonant peaks shift in the reflectivity spectrum of porous silicon microcavities(PSMs). The optical sensing model is set up by applying Bruggeman effective medium approximation theory, capillary condensation process and transfer matrix theoretically analytical method of one-dimensional photonic crystals. At the same time, comprehensively researched on are the sensing characteristics of PSMs which are exposed to give concentration organic vapors. At last, made is the theoretical simulation for sensing model of the PSMs in case of saturation by using computer numerical calculation, and found is the linearity relation between the refractive index of organic solvent and the peak-shift. At the same time deduced is the peak-shift as a function of the concentration of ethanol vapors.
文摘We revisit Auslander-Buchweitz approximation theory and find some relations with cotorsion pairs and model category structures.From the notion of weak-cogenerators,we introduce the concept of Frobenius pair(X,ω)in a triangulated category T.We show how to construct from a Frobenius pair(X,ω)a triangulated model structure on X^(∧).
