Singular periodic solutions of a class of elastodynamics equations

Xuegang Yuan,Yabo Zhang 한국전산응용수학회 2009 Journal of applied mathematics & informatics Vol.27 No.3

A second order nonlinear ordinary differential equation is obtained by solving the initial-boundary value problem of a class of elastodynamics equations, which models the radially symmetric motion of a incompressible hyper-elastic solid sphere under a suddenly applied surface tensile load. Some new conclusions are presented. All existence conditions of nonzero solutions of the ordinary differential equation, which describes cavity formation and motion in the interior of the sphere, are presented. It is proved that the differential equation has singular periodic solutions only when the surface tensile load exceeds a critical value, in this case, a cavity would form in the interior of the sphere and the motion of the cavity with time would present a class of singular periodic oscillations, otherwise, the sphere remains a solid one. To better understand the results obtained in this paper, the modified Varga material is considered simultaneously as an example, and numerical simulations are given. A second order nonlinear ordinary differential equation is obtained by solving the initial-boundary value problem of a class of elastodynamics equations, which models the radially symmetric motion of a incompressible hyper-elastic solid sphere under a suddenly applied surface tensile load. Some new conclusions are presented. All existence conditions of nonzero solutions of the ordinary differential equation, which describes cavity formation and motion in the interior of the sphere, are presented. It is proved that the differential equation has singular periodic solutions only when the surface tensile load exceeds a critical value, in this case, a cavity would form in the interior of the sphere and the motion of the cavity with time would present a class of singular periodic oscillations, otherwise, the sphere remains a solid one. To better understand the results obtained in this paper, the modified Varga material is considered simultaneously as an example, and numerical simulations are given.

Stability of Hybrid Impulsive and Switching Stochastic Systems with Time-delay

Xuegang Tan,Bin Hu,Zhi-Hong Guan,Rui-Quan Liao,Jiang-Wen Xiao,Yuehua Huang 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4

This paper investigates a model of hybrid impulsive and switching stochastic systems (HISSS) with time-delay. Several stability criteria, including the globally asymptotical and exponential stability criteria in the pth moment and mean square, are established by using Itô formula, a generalized switching Lyapunov functions and some relating techniques. Especially, a more general Lyapunov-Krasivskii functional is constructed, and it is observed that the mean square asymptotic and exponential stability conditions of HISSS are delay-dependent. A numerical example shows that the obtained stability results can reduce the conservativeness.

SINGULAR PERIODIC SOLUTIONS OF A CLASS OF ELASTODYNAMICS EQUATIONS

Yuan, Xuegang,Zhang, Yabo The Korean Society for Computational and Applied M 2009 Journal of applied mathematics & informatics Vol.27 No.3

A second order nonlinear ordinary differential equation is obtained by solving the initial-boundary value problem of a class of elas-todynamics equations, which models the radially symmetric motion of a incompressible hyper-elastic solid sphere under a suddenly applied surface tensile load. Some new conclusions are presented. All existence conditions of nonzero solutions of the ordinary differential equation, which describes cavity formation and motion in the interior of the sphere, are presented. It is proved that the differential equation has singular periodic solutions only when the surface tensile load exceeds a critical value, in this case, a cavity would form in the interior of the sphere and the motion of the cavity with time would present a class of singular periodic oscillations, otherwise, the sphere remains a solid one. To better understand the results obtained in this paper, the modified Varga material is considered simultaneously as an example, and numerical simulations are given.

Remote Sensing Image Fusion Based On IHS and Dual Tree Compactly Supported Shearlet Transform

Chang Duan,Qihong Huang,Xuegang Wang,Shuai Wang,Hong Wang 보안공학연구지원센터 2014 International Journal of Signal Processing, Image Vol.7 No.5

This paper presents a novel remote sensing image fusion algorithm, which implements the intensity-hue-saturation (IHS) transform on panchromatic sharpening of multispectral data and the dual-tree compactly supported shearlet transform (DT CSST) during fusion. Shearlet transforms can provide almost optimal representation of the anisotropic features of an image. The spatial domain discrete implementation, the compactly supported shearlet transform (CSST), which represents the directions by dilation operations, are selected in the proposed fusion method. Since most of the prominent features of images, such as edges and regions, have limited sizes in the spatial domain, CSST is very suitable for image fusion. However, the conventional CSST is shift-variant, which causes distortions in fused images. With the embedded dual-tree (DT) sturcture in the CSST, the shift-variant properties can be effectively reduced. Combining the IHS transform and the DT CSST, an effective panchromatic and multispectral image fusion method is proposed in this paper. The experiments’ results suggest that the proposed method extract more spatial information from panchromatic images with less lost in spectral consistency compared to other fusion methods which are based on discrete wavelet transform (DWT), à trous wavelet transform, à trous shearlet transform, the dual-tree complex wave transform ( DT CWT), or the Curvelet transform.

Image Denoising via Fast and Fuzzy Non-local Means Algorithm

Junrui Lv,Xuegang Luo 한국정보처리학회 2019 Journal of information processing systems Vol.15 No.5

Non-local means (NLM) algorithm is an effective and successful denoising method, but it is computationallyheavy. To deal with this obstacle, we propose a novel NLM algorithm with fuzzy metric (FM-NLM) for imagedenoising in this paper. A new feature metric of visual features with fuzzy metric is utilized to measure thesimilarity between image pixels in the presence of Gaussian noise. Similarity measures of luminance andstructure information are calculated using a fuzzy metric. A smooth kernel is constructed with the proposedfuzzy metric instead of the Gaussian weighted L2 norm kernel. The fuzzy metric and smooth kernelcomputationally simplify the NLM algorithm and avoid the filter parameters. Meanwhile, the proposed FMNLMusing visual structure preferably preserves the original undistorted image structures. The performance ofthe improved method is visually and quantitatively comparable with or better than that of the current state-ofthe-art NLM-based denoising algorithms.

Composition and Inheritance are Different

Chengying Chi,Xuegang Zhan 보안공학연구지원센터 2015 International Journal of Software Engineering and Vol.9 No.12

Inheritance and composition are two different and closely related techniques that allow a modeller to extend the properties of a class. The mantra “favor composition over inheritance” has been around for many years. Many examples have been given to support such a conclusion. In this paper we discuss a special type of inheritance . direct inheritance versus single member composition, and show that inheritance is more accurate and concise in these cases.

A Distributed, Hybrid Energy-Efficient Clustering Protocol for Heterogeneous Wireless Sensor Network

Jun Wang,Xuegang Zhu,Yong Cheng,Yongsheng Zhu 보안공학연구지원센터(IJGDC) 2013 International Journal of Grid and Distributed Comp Vol.6 No.4

Study on the Super-resolution Reconstruction Algorithm for Remote Sensing Image Based on Compressed Sensing

Qiang Yang,HuaJun Wang,Xuegang Luo 보안공학연구지원센터 2015 International Journal of Signal Processing, Image Vol.8 No.6

Image super resolution reconstruction has important significance in remote sensing image feature extraction and classification etc.. Because the remote sensing image size is larger, it is difficult to super resolution reconstruction using multiple images, the compressed sensing (CS) theory was introduced into the super-resolution reconstruction. Algorithm designed the low pass filter to reduce the sample correlation matrix and wavelet, at the same time, the algorithm selects the partial Hadamard-matrix as the measurement matrix, it has faster reconstruction speed and low storage requirements, which ensure that the image reconstruction keep with the RIP criterion of compressed sensing theory . Finally, this paper realizes the remote sensing image super resolution reconstruction through the improved iterative algorithm. Experiments show that the reconstructed images of the PSNR value has increased, the reconstructed image has a better visual effect.

Image Denoising via Fast and Fuzzy Non-local Means Algorithm

Lv, Junrui,Luo, Xuegang Korea Information Processing Society 2019 Journal of information processing systems Vol.15 No.5

Non-local means (NLM) algorithm is an effective and successful denoising method, but it is computationally heavy. To deal with this obstacle, we propose a novel NLM algorithm with fuzzy metric (FM-NLM) for image denoising in this paper. A new feature metric of visual features with fuzzy metric is utilized to measure the similarity between image pixels in the presence of Gaussian noise. Similarity measures of luminance and structure information are calculated using a fuzzy metric. A smooth kernel is constructed with the proposed fuzzy metric instead of the Gaussian weighted L2 norm kernel. The fuzzy metric and smooth kernel computationally simplify the NLM algorithm and avoid the filter parameters. Meanwhile, the proposed FM-NLM using visual structure preferably preserves the original undistorted image structures. The performance of the improved method is visually and quantitatively comparable with or better than that of the current state-of-the-art NLM-based denoising algorithms.

Analysis of Impact of Terrain Factors on Landscape-scale Solar Radiation

Xiaodan Mei,Wenyi Fan,Xuegang Mao 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.10

Incident solar radiation is one of the major sources of energy for driving biological and physical processes on earth. In this paper, simple conversion factors are designed to determine how the four landforms (i.e. plain, plateau, hill and mountain) will affect incident solar radiation at one month intervals using the ArcGIS tool appropriate for regional solar radiation analysis. A comparison is made between simulation results and those measurements taken in actual radiation stations, providing a correlation R2 of 0.9063. Results indicate first, that if the ratio of the monthly mean of the DEM-based regional solar radiation to the monthly mean of the hypothesis DEM-based regional solar radiation is defined as the conversion factor (R) of the solar radiation and the ArcGIS tool for regional solar radiation analysis is employed, then the computation can be simplified and the impact of terrain factors on incident solar radiation can be correctly represented. Secondly, with each of the four landforms, R varies according to the season, slope gradient and aspect; the season induces more impacts than the terrain factors; R increases first and then decreases when the aspect changes clockwise, but decreases continuously with an increase in slope grade; R varies in a complex way in the case of mountains, especially for grade-five slopes. Thirdly, R increases initially and then decreases in a sinusoidal manner with an increase in aspect under the influence of slope gradient during the winter; R varies in a linear and somewhat symmetric manner (monotone increasing, monotone decreasing and stable) with the increase in slope gradient and under the influence of the aspect. These results are helpful in studying the impact of terrain factors of different landforms on incident solar radiation on the landscape scale using the simple conversion factors.