Xiaoying Chen^{1, 2, *}, Shijun Zhao², Xiaolei Wang², Xuejin Sun², Jing Feng², Nan Ye³

CMC-Computers, Materials & Continua, Vol.61, No.2, pp. 861-875, 2019, DOI:10.32604/cmc.2019.06230

Abstract It is important to extract texture feature from the ground-base cloud image for cloud type automatic detection. In this paper, a new method is presented to capture the contour edge, texture and geometric structure of cloud images by using Contourlet and the power spectrum analysis algorithm. More abundant texture information is extracted. Cloud images can be obtained a multiscale and multidirection decomposition. The coefficient matrix from Contourlet transform of ground nephogram is calculated. The energy, mean and variance characteristics calculated from coefficient matrix are composed of the feature information. The frequency information of the data series from the feature vector… More >

Mira Mitra¹, S. Gopalakrishnan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.15, No.1, pp. 49-68, 2006, DOI:10.3970/cmes.2006.015.049

Abstract In this paper, a 2-D Wavelet based Spectral Finite Element (WSFE) is developed and is used to study wave propagation in an isotropic plate. Here, first, wavelet approximation is done in both temporal and one spatial (lateral) dimension to reduce the governing partial differential wave equations to a set of Ordinary Differential Equations (ODEs). Daubechies compactly supported orthogonal scaling functions are used as basis which allows finite domain analysis and easy imposition of initial/boundary conditions. However, the assignment of initial and boundary conditions in time and space respectively, are done following two different methods. Next, the reduced ODEs are solved… More >

Yanxin Wang^{1, *}, Li Zhu¹, Zhi Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.2, pp. 339-350, 2019, DOI:10.31614/cmes.2019.04575

Abstract An Euler wavelets method is proposed to solve a class of nonlinear variable order fractional differential equations in this paper. The properties of Euler wavelets and their operational matrix together with a family of piecewise functions are first presented. Then they are utilized to reduce the problem to the solution of a nonlinear system of algebraic equations. And the convergence of the Euler wavelets basis is given. The method is computationally attractive and some numerical examples are provided to illustrate its high accuracy. More >

Haijian Shao^{1, 2}, Xing Deng^{1, 2, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.3, pp. 277-293, 2018, DOI:10.3970/cmes.2018.114.277

Abstract High accurary in wind speed forcasting remains hard to achieve due to wind’s random distribution nature and its seasonal characteristics. Randomness, intermittent and nonstationary usually cause the portion problem of the wind speed forecasting. Seasonal characteristics of wind speed means that its feature distribution is inconsistent. This typically results that the persistence of excitation for modeling can not be guaranteed, and may severely reduce the possibilities of high precise forecasting model. In this paper, we proposed two effective solutions to solve the problems caused by the randomness and seasonal characteristics of the wind speed. (1) Wavelet analysis is used to… More >

Jinyou Xiao, Wenjing Ye

The International Conference on Computational & Experimental Engineering and Sciences, Vol.18, No.4, pp. 101-102, 2011, DOI:10.3970/icces.2011.018.101

Abstract Traditional boundary element methods (BEMs) suffer from densely populated system matrices. In recent years, acceleration techniques like the wavelet BEM (WBEM) have been developed which reduce the complexity considerably. In WBEM, one uses appropriate wavelet bases for the discretization, yielding numerically sparse matrices which result in extremely fast matrix-vector multiplications. However, in conventional WBEM the wavelets are constructed by uniform refinement of parametrically described patches. Such approaches have difficulties in dealing with practical problems with complicated geometries because patch-wise surface parameterization is generally not available. To avoid this limitation, Tausch proposed a method in [1] to construct wavelets directly on… More >

Yong Huang¹, Hui Li¹, Jinping Ou^1,2

The International Conference on Computational & Experimental Engineering and Sciences, Vol.12, No.2, pp. 53-64, 2009, DOI:10.3970/icces.2009.012.053

Abstract A new damage identification method based on Fractal theory and wavelet packet transform is presented in the paper. The damage identification method utilize frequency-based domain message, time-based domain message and space based domain message effectively. NeXT method were first employed to reduce loading effect of random vibration measured from structures and then the vibration sinal were decomposed into the certain level wavelet packet components. For every time array of wavelet packet component then need to calculate the mean FD values as the ultimated FD values to reduce noise effect. The location of damage in the beam can be determined by… More >

S. Tanaka¹, H. Okada¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.4, pp. 217-224, 2007, DOI:10.3970/icces.2007.003.217

Abstract It has been recognized that the bottle-neck in solid/structural analyses using the finite element method is in their model generation phase. Methodologies that eliminate the needs for "elements" have been proposed by many researchers. They can be categorized into "meshless" and "virtually meshless" finite element methods. The "meshless" method may be represented by moving least square Ptrov-Galerkin (MLPG) method [1] and element free Galerkin Method (EFGM) [2]. The free-mesh method [3] and voxel finite element method [4], etc. are classified to be the "virtually meshless" approaches. The "meshless" methods eliminated needs for element connectivity information in their input data and… More >

Yanan Liu¹, Yinghua liu¹, Zhangzhi Cen¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.3, pp. 139-144, 2007, DOI:10.3970/icces.2007.003.139

Abstract In this paper, a Daubechies(DB) wavelet-based meshless method is proposed to analyze 2-D elastoplasticity problems. Using DB wavelet scaling functions and wavelet functions as basis functions to approximate the unknown field functions, there is no need to construct the shape functions costly as done in FEM and conventional meshless methods. Incremental formulations are established for solution of 2-D elastoplasticity problems. In addition, the property of DB wavelet is used to make the method concise in formulations, flexible in applications and easy to realize. Due to the lack of Kroneker delta properties in scaling functions and wavelet functions, the penalty method… More >

C. K. Madhusudana¹, N. Gangadhar¹, Hemantha Kumar, Kumar,^*,1, S. Narendranath¹

Structural Durability & Health Monitoring, Vol.12, No.2, pp. 111-127, 2018, DOI: 10.3970/sdhm.2018.01262

Abstract This paper presents the fault diagnosis of face milling tool based on machine learning approach. While machining, spindle vibration signals in feed direction under healthy and faulty conditions of the milling tool are acquired. A set of discrete wavelet features is extracted from the vibration signals using discrete wavelet transform (DWT) technique. The decision tree technique is used to select significant features out of all extracted wavelet features. C-support vector classification (C-SVC) and ν-support vector classification (ν-SVC) models with different kernel functions of support vector machine (SVM) are used to study and classify the tool condition based on selected features.… More >

Xingwu Zhang¹, Jixuan Liu², Xuefeng Chen^1,3, Zhibo Yang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.5, pp. 405-425, 2015, DOI:10.3970/cmes.2015.109.405

Abstract Plane truss is widely used in mechanical engineering, building engineering and the aerospace engineering et al.. The precisely analysis of plane truss is very important for structural design and damage detection. Based on the generalized variational principle and B spline wavelet on the interval (BSWI), the multivariable wavelet finite element for plane truss is constructed. First, the wavelet axial rod element and the multivariable wavelet Euler beam element are constructed. Then the multivariable plane truss element can be obtained by combining these two elements together. Comparing with the traditional method, the generalized displacement and stress are treated as independent variables… More >