Papers by Keyword: Inversion

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Authors: Yong Kang Zhang, Yu Long Li, Hong Bing Zhang
Abstract: Identification of a bird constitutive model and its parameters is a very difficult work in bird-impact coupling solution. In order to identify the constitutive model and the parameters simultaneously, an inversion analytic model for the bird material parameters is given based on penalty function method and nonlinear optimization principle, and then combining the model preferential criterion proposed in this paper, the identification system of the bird constitutive model is established with ANSYS Parametric Design Language (APDL). Finally, the feasibility and practicability of this identification method are verified by an example.
Authors: Rui Yang, Guang Xun Chen, Pan Ke Qin, Neng You Wu, Jia Shun Yu
Abstract: In order to improve the resolution and accuracy of the inversion, this paper proposed a new inversion method. By introducing constraint sparse spike inversion, the new method can fully take the advantages of high vertical resolution of logging data and the preferable transverse continuity of the seismic data to improve the resolution of the profiles and the quality of imaging and inversion in specific areas. Experimental results showed that this solution can deduce more precise and reasonable inversion result than other inversion solution. Constraint sparse spike inversion can generate reflection coefficients with broad frequency band and solve the marking problems preferably, thereby makes the impedance model obtained from the inversion even close to the actual situation underground.
Authors: Xue Jiao Hou, Jing Liu, Wei Cui
Abstract: Beased on in Situ Water Quality Data and Hyperspectral Data from HJ-1A satellite in Chaohu Lake, through Contrasting the Object-Oriented Chlorophyll-a Inversion Precision Of single Band with Two-Band Model, the Results Show: (1) In Hyperspectral Object-Oriented Remote Sensing inversion, the Inversion Effect of Choosing Combination Model to Segment Is superior to that of Choosing the Single Band Directly, and Using Combination model to Segment can Certain Degree Solve the Problem that Commercial Softwares cannot Segment all Hyperspectral Data at the same Time.(2)When Inversing Chlorophyll-a Concentration with Hyperspectral Data, the Single Bands Constituting the Optimal Model Are not Always in the Traditional Characteristics Band Range of Chlorophyll-a. so All bands should be Comprehensively Analyzed to take Full Advantages Of hyperspectral Data when Inversing. these Conclusions Will provide Basis for the Future Segmentation Object Selection of Object-Orientedon Hyperspectral Lakes Chlorophyll-a Inversion and Certain Reference for Band Selection of Hyperspectral Inversion Model.
Authors: Dong Dong Zhang, Xin Feng, Jing Zhou
Abstract: A regularization based method of inversely analyzing the material parameters for the gravity dams is presented in this paper. The measured noise of the displacement often leads to the ill-posed solutions of the dam inversion. A least square scheme was adopted for the inverse analysis by using of the displacement measurements, and the L-curve algorithm was proposed to perform the regularization in the inversion computation. The proposed method actually utilizes the sensitivity of the measured displacements with respect to the sub-regional material parameters. Thus a simplified algorithm was developed to calculate the sensitivity coefficients by using the standard finite element procedure. To investigate the effectiveness of the proposed method, the numerical simulations on a concrete gravity dam were carried out. The results demonstrate that the presented method can accurately obtain the material parameters of the dam by using of the inverse analysis, which has the potential for assessing the integrity of the gravity dams.
Authors: Hong Yan Xi, Jun Hua Zhang, Jing Sun, Jing Li, You Qing Wang, Xian Mai Chen, Fu Tong Wang
Abstract: Strong earthquake ground motion leads to residual displacements of gravity retaining walls. Since large deformation occurs in foundation soil, nonlinear mechanical behavior should not be neglected in numerical modeling. The inversion methodology in geophysics is borrowed here to study the nonlinearity, i.e. the variation of shear modulus and damping ratio with the increase of shear strain of soil. A simplified model for the seismic displacement of retaining walls is combined with a genetic algorithm for the inversion. The dynamic shear modulus and damping ratio curves, representing the nonlinear property of foundation soil in a centrifuge test for gravity retaining walls, is obtained by the use of an inversion scheme. The result indicates that, for low level of shear strain, the shear modulus is larger than that used in the literature, implying that the model ground may be stiffer than expectation. For high level of shear strain, the inverted damping ratio is larger than the conventional one, which has efficiently suppressed an overestimation of seismic displacements. It is also displayed that the inversion method is an effective way to obtain quantitatively the dynamic nonlinearity of foundation soil of gravity retaining walls.
Authors: Hai Xia Li, Hai Long Yu, Ping Chuan Zhang
Abstract: A rapid method for 3D physical properties inversion based on separation and continuation of potential field are introduced in this paper. The inversion technique characterized by faster computing speed, it does not need to divide the underground field sources region into many rectangular blocks in one time and does not need to solve linear algebraic equations as well. So, this technique can overcome the requirement of large computer memory, unstable solution and computation time bottleneck which hinders the application of 3D inversion to practice. The method is used to apparent magnetic susceptibility inversion of magnetic anomaly in a iron mine area, the inversion results show that the method has good accuracy, and the advantages of strong stability and a high computation speed, and is suitable for 3D inversion of magnetic data in large area.
Authors: J.J. Chen, Jian She Li, Y.D. Gu
Abstract: With the increase of the difficulty and intensity on competitive movement, the rate of sport injury will happen in training and competing frequently. The metatarsal is one of the most prone to injury part in the human body. The incidence of metatarsal injuries is rising in recently years. In this study, Pedar-X plantar pressure measure system and Novel emed pressure distribution measure plate were used in order to get the dynamics data in normal landing and inverted landing. The research concluded that: metatarsal peak stress had been transferred from the first metatarsal to the fifth metatarsal with increasing of varus angle. When the foot was in inverted state, stress distribution of metatarsal changed significantly. Lateral metatarsal played a major role in supporting function. Also, forefoot pressure distribution changed a lot in different functional sports shoes. The purpose is to provide the reliable correlative theoretical basis for improving sport equipments and security protection recommendations for people to engage in sports.
Authors: Hong Tang, Wen Bin Zheng
Abstract: Particulate flow is commonly encountered in industries as well as in many other chemical and mechanical engineering applications. The accurate measurement of particle size distribution is of the utmost importance since it decides the physical and chemical characteristic of the particles. The light extinction method can be used for in-line monitoring of particle systems thus providing real time measurements of both particle size distribution and particle concentration. In light extinction particle sizing, a classification inversion algorithm is proposed for the circular cylinder particles. The measured circular cylinder particle system is inversed with different particle distribution functions and classified according to the inversion errors in the dependent model. The simulation experiments illustrate that it is feasible to use the inversion errors of object functions to inverse the circular cylinder particle size distribution in the light extinction particle sizing technique. This classing inversion algorithm can avoid the defects that the type of the size distribution must be assumed beforehand for the light extinction method.
Authors: Hong Tang, Wen Bin Zheng
Abstract: In light extinction particle sizing, a classification inversion algorithm is proposed for the non-spherical particles. The measured spheroidal particle system is inversed with different particle distribution functions and classified according to the inversion errors in the dependent model. Simulation experiments illustrate that it is feasible to use the inversion errors to inverse the spheroidal particle size distribution in the light extinction particle sizing technique and the inversion results are steady and reliable, which avoid the defects that the type of the size distribution must be assumed beforehand for the light extinction method.
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