Papers by Keyword: Iteration Method

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Authors: Tao Ma, Mei Ping Wu, Xiao Ping Hu, Guan Nan Li
Abstract: Instability is the inherent limitation of downward continuation. Based on integral iteration idea and regularization theory, a regularization method is proposed for downward continuation of potential fields. We also present an L-curve method for the selection of regularization parameter. The improved method is tested on model data both with and without noise. The results show that the new method is much more stable than the iteration method, especially in dealing with low signal-to-noise data, and that it also has a large downward continuation distance.
Authors: Shang Ping Chen, Wen Juan Yao, Sheng Qing Zhu
Abstract: In this paper, a three-stage softening load transfer model, based on existing experimental data of super-long piles, is proposed; the hyperbola load transfer model is adopted to simulate the nonlinear deformation of pile-tip soil; and the elastic-plastic model of concrete is introduced, giving consideration to the super-long pile shaft deformation under heavy axial loads. Then the models above are implemented into pile-soil load transfer differential equation, and after being solved by iteration method, the nonlinear method for load transfer model of super-long pile in layered soil is established. After that programming of the model calculation is worked out. By comparison with engineering instance, it is shown that the method proposed in this paper is convenient and reliable in engineering practice.
Authors: Xue Yuan Zhang
Abstract: According to the law of energy conservation and the second law of Kepler, this paper obtains the spacecraft velocity in perilune and apolune. Based on trajectory inversion thought, this paper obtains position and velocity direction in the perilune and apolune. For the five sub stages of soft landing, this paper discusses the optimal control strategy: establishing optimization model of genetic algorithm for the main deceleration section, the terminal constraint condition is reflected on the fitness function through the penalty function, combined with linear iterative thought, the winner engine thrust and direction angle are obtained. Aiming at the rapid adjustment period, the spacecraft angle change is done equivalent decomposition and discrete linear, so the thrust can be obtained through the angle change provided by adjusting attitude engine and combined with rigid body motion law.
Authors: Xin An Wu, Li Xue Li, Yi Hui Zheng, Xin Wang, De Min Cui, Jing Sun
Abstract: Grounding grid was considered as a pure-resistor network and its inner information was obtained through limited grounding leads. A set of diagnostic equations was established based on Tellegen’s theorem. Iteration method and Nonnegative Least Squares method (NNLS) were used to solve it. To verify this method, corrosion diagnosis of single-branch and two-branch was simulated. An optimal plan was proposed in the simulating calculation, which diagnosed step by step and added measurement nodes according to the result of each step. This method is able to determine the corrosion position and degree reliably and the optimal plan has higher efficiency and less workload.
Authors: Liang Tang, Zhi Chao Wang, Lei Gao
Abstract: To solve large linear equations using SOR method, the most important thing is to ascertain relaxation factor. Considering current methods can not get the factor from global aspect, iteration times become larger and speed become slower. We pose a method to fix optimal factor using global search quality, genetic operational quality and compare the factor value obtaining from PSO algorithm and genetic algorithm, parabolic method. As a result, it shows that it is easier for PSO method to get optimal value than genetic and parabolic method from simulation result. PSO algorithm has huge advantage on solving global optimal problems. It is definite that PSO algorithm has great advantage then other methods and this method, and another advantage is it’s feasibility and convenience.
Authors: Li Gang Cai, Xiao Shi, Yong Sheng Zhao
Abstract: According to the characteristics of constant flow and closed hydrostatic rotary table used in heavy duty CNC machine, in order to consider the interaction between structural deformation of worktable and the supporting force of oil pads, an iteration method between hydrostatic theory calculation and finite element method (FEM) is used to get the real supporting force of each oil pad at different carrying state. The result is compared with the situation which is not considering the deformation of worktable and the difference between them can be used to guide the design of hydrostatic oil pads. The optimal radius of supporting point of work piece is also achieved using this method, which can provide theory basis for supporting point distribution of heavy work piece.
Authors: Qing Jiang Chen, Fang Lin
Abstract: The frame theory has been one of powerful tools for researching into wavelets. The notion of the bivariate generalized multiresolution structure (BGMS) is presented. The concepts of Bessel sequences and orthogonal bivariate pseudoframes are introduced. Two Bessel sequences are said to be orthogonal ones if the composition of synthesis operator of one sequence with the analysis operator of the other is the zero-operator. It is characterized that when two Bessel sequences are orthogonal while the Bessel sequences possess the form of translates of a finite number of bivariate functions in . A constructive method for affine frames of based on a BGMS is established.
Authors: Guo Xin Wang, De Lin Hua
Abstract: The frame theory has been one of powerful tools for researching into wavelets. In this article, the notion of orthogonal nonseparable quarternary wavelet wraps, which is the generalizati- -on of orthogonal univariate wavelet wraps, is presented. A novel approach for constructing them is presented by iteration method and functional analysis method. A liable approach for constructing two-directional orthogonal wavelet wraps is developed. The orthogonality property of quarternary wavelet wraps is discussed. Three orthogonality formulas concerning these wavelet wraps are estabished. A constructive method for affine frames of L2(R4) is proposed. The sufficient condition for the existence of a class of affine pseudoframes with filter banks is obtained by virtue of a generalized multiresolution analysis. The pyramid decomposition scheme is established based on such a generalized multiresolution structure.
Authors: Hong Lin Guo, Yu Min Yu
Abstract: In this article, the notion of orthogonal nonseparable four-dimensional wavelet packs, which is the generalization of orthogonal univariate wavelet packs, is introduced. A new approach for constructing them is presented by iteration method and wavelets as well wavelet frames. The biorthogonality properties of four-dimensi- -onal wavelet packets are discussed. Three biorthogonality formulas concerning these wavelet packs are estabished. A necessary and sufficient condition for the existence of the pyramid decomposition scheme of space is presented.
Authors: Ying Di Hu, Shen Guang Gong, Xue Fei Yang
Abstract: An iteration method was advanced to solve the problem of ship’s static electric field extrapolation to shallow depth. Based on the vertical partial derivative of each component of static electric field and using derivation formula, the static field values of the points on the target depth that had same coordinates as the measured points were calculated iteratively. The simulation result shows that this method can be easily carried out and has a high calculation precise.
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