Papers by Keyword: Inversion

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.

Abstract: The measurement of the complex permittivity of big structure composite material has always been a key and difficulty in the preparation of electromagnetic functional materials. In this paper the average dielectric constant inversion of coconut fiber/gypsum composite in S band is studied based on λ/4 absorption spectrum. First the absorbing effects of the prepared coconut fiber gypsum composite materials are tested with method of flat reflection. Then the equivalent complex permittivity is inversed with the inversion theory. Further the experimental verification is preceded that the theoretical and experimental absorbing curves whose peak positions are respectively at 3.05GHz and 2.45GHz are quite matched. And the study shows that this method is scientific and effective, and it can provide technical support for the baroque electromagnetic functional composite materials.

Abstract: The chlorophyll content in crop leaf is an indicator of health situation and the crop yield. Hence, it is very important to retrieval of accurate chlorophyll content in paddy rice. This research selected Zhengyi town of Suzhou city as the study area, measurements were acquired during the summer of 2009, in a field campaign in which for 288 rice leaf samples, rice hyperspectral data was measured by ASD FieldSpec3 spectrometer, chlorophyll content was measured by using a SPAD-502 chlorophyll meter. And the parameters of support vector machine were optimized by genetic algorithm, then support vector machine and PROSPECT radiative transfer model were adopted to build estimation model, which used to retrieve the chlorophyll content of rice. The results indicate that: the coefficient of determination for the rice chlorophyll estimation model is 0.8825, and RMSE is 8.7491. Research of this paper provides some reference for quickly and accurately estimating the chlorophyll content in rice.

Abstract: This paper puts forward the method of obtaining new types of RV transmission. Research shows that the topological graph can effectively express the topology unit and topological structure of RV transmission; the process that through topology degradation and evolutionary method to Obtain the RV transmission of topology map and through the topology inversion to get the new organization is practical and feasible. The topological evolution methods have tie bar evolution, tree, increasing gear tooth ring and mixing superimposed evolution. The RV transmission topology inversion is implemented by the way of gear ring, Gear meshing, the gear, the shaft, tie rod and the frame. Method was developed to get the evolutions of a variety of RV transmission, and the evolution of a graph of the inverse mapping was enumerated. The topology graph theory methods used in the RV transmission for the structure of RV transmission innovation provides an important theoretical method.

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.

Abstract: Volume fracturing is the key technology that has made the development of tight oil formations economical. Well testing is often used to obtain formation parameters in oil field after volume fracturing in tight oil formations, which is time-consuming and accuracy is low. Based on a new analytical solution methodology, this paper presents a simple and efficient approach by matching the production data to obtain formation parameters, just like formation permeability, fracture conductivity, dimensionless conductivity, propped length and so on. The numerical solution is applicable for finite-conductivity vertical fractures in rectangular shaped reservoirs. The mathematical formulation is based on the method of images with no flow boundaries for symmetrical patterns.

Abstract: The inverse analysis method based on genetic algorithm has been widely applied, but the general genetic algorithm is not applicable to the objective function as a non-analytic formula, so that the clear target function formula is often difficultly been obtained in the practical engineering. In order to solve the problem, the historical data are studied by neural network with the neural network embedded into the genetic algorithm, so as to establish the effective neural network model to replace the target function formula. At the same time, the corresponding fitness function is constructed for the optimal calculation. This method has been used for the inversion analysis on the initial damage of concrete, and the mechanical parameter inversion method is put forward based on the uniform design-genetic algorithm-neural network ensemble theory. Moreover, the method is verified by a calculation example, the results show that the initial damage value of concrete can effectively be obtained.

Abstract: As the geological condition of western Luming molybdenum mine is broken and there are faults through, to find out the geological structures of west mine is quite significant for the study of Luming mine slope stability. With EH4 geophysical technology to detect west Luming molybdenum geological condition, the data of the detection point was collated and sorted out, through the inversion method, two faults F3 and F4 was inferred in the west zone of LuMing mine, which is likely to cause slope instability phenomena. What is more, at the northwest of the pit, lithology with water was composed of alluvial deposits and broken sediments, the depth of the strata with water is more than 80 miles. So the impact of water on slope stability should be fully considered during mining process.

Abstract: The inverse problem is an important interdisciplinary subject, which receives more and more attention in the fields of mathematics, computer science, information science and other applied natural sciences in recent years. Nowadays, the inverse problem is more and more commonly applied than before, e.g., in image processing and geophysics. This trend promotes the development of both the advanced computing methods and high performance computing techniques. The high performance of computing problems for inverse algorithms is discussed in this paper, which is meaningful for the research of applied inversion subjects.

Abstract: In order to obtain accuracy interval velocity and improve the quality of imaging of velocity volume, so as to better describe the geological structure and reservoir of gas hydrate in specific area, a new interval velocity inversion combination method is proposed in this paper. By introducing wave ray tracing algorithm and velocity field structuring and smoothing algorithm, this new inversion solution can deduce more accuracy and reasonable interval velocity than other normal inversion methods. Empirical results shows that velocity profile has higher resolution and can finely reflect the occurrence status and spatial distribution of gas hydrate.