Papers by Keyword: Multi-Scale

Abstract: The upward gas-liquid cross flow around a square cylinder was simulated using two fluid model with the multi-scale turbulent model based on the variable interval time average method. The computational results show that the multi-scale turbulent model can successfully simulate lift coefficient, drag coefficient and vortex shedding characteristics of flow around a body, and can also accurately predict the void fraction distribution and flow structure. Compared with the experimental data, the results of the multi-scale model are better than that of Standard k-ε model and RNG k-ε model. Hence, the study of this paper certificates further that this model can be used in the simulation of the gas-liquid flow around bluff bodies and outher engineering application.

Abstract: This paper presents a facial expression recognition algorithm based on multi-channel integration of Gabor feature. First, a Gabor wavelet filter extracts facial features with 5 scales and 8 orientations, and then transform the 40 channels into 13 channels according to the maximum rule presented in this paper. Second, we reduce the dimension of expression features by the method of PCA+LDA. At last, expression features are classified using the nearest neighbor method. The experiments involve two databases and show that the proposed algorithm can recognize facial expression in high rate.

Abstract: This paper adopts statistical learning theory and optimization theory to the analysis of the algorithm theory, probe into its theoretical foundation. The existing theoretical analysis on the basis of the establishment of clustering model algorithm design, code realization and finally a lot of different data set of test, choose soil data as a test database, will be in the database on a large number of data mining experiment to verify the performance of the proposed algorithm. The test result feedback back will further deepen the theoretical research or correct theory already mistakes, new theory and will continue to guide experiments, both mutual promoting common development.

Abstract: For the purpose of extract the fault feature hidden by strong noise background in rolling bearing fault signal, a morphological undecimated wavelet method was proposed. A undecimated wavelet decomposition operator called gradient filter was presented based on an open-closed and closed-open mixed filter. The morphological gradient filter was used to extract the impulse feature of signal. The type and the length of structure elements used in these filters were alterable adapt to the signal. The method was applied to analyze the simulated data and measured vibration signals from the bearing with fault. The results confirm that the proposed method is feasible in impulse feature extraction of signal, and it is more effective than other traditional morphological undecimated wavelet methods.

Abstract: Real-time and seamless visualization of the Earth terrain based on Global Discrete Grids is a subject of considerable current attention. In this paper a multi-scales visualization model of the global terrain based on DQG (Degenerate Quadtree Grid) is approached. Our approach starts with a partition method, called Degenerate Quadtree Grid (DQG) and an encoding scheme of the corresponding grids is introduced briefly. Next, a multiple level of detail model related to viewpoint is presented. In this model, a criterion of terrain model simplification based on viewpoint and roughness of the degenerate quadtree node is developed. Then, making full use of the characteristics of quadtree structure, the cracks within quadtree blocks are induced by simplification. Thus, the cracks splicing are all seamless. In the end, the experiment and analysis are made with the global terrain data, GTOPO30. The results illustrate that: (1) the global terrain based on the DQG is seamless, hierarchical, and regular over the whole Earth; (2) the quantity of global DEM data can be reduced significantly; (3) the visual effect of the global multi-scale terrain is seamless by the model simplification ensuring the accuracy and efficiency of the terrain display.

Abstract: The disparity map of dynamic programming method is poor. To overcome it, a stereo matching method based on multi-scale plane set is proposed in this paper. This method converts the structural model into the plane set. Define the key plane. Then the key planes are in a high-scale. The other planes are in the low scale. Stereo matching the multi-scale plane set using dynamic programming method. The experimental results show that: this method can solve the dynamic programming algorithm`s problem that disparity map has low matching accuracy and a lot of stripes error.

Abstract: This paper uses the combination between support vector machine and multi-scale principal component analysis. For motor fault detection, the principal component model can be established in various scales. Through T2 and Q statistic judgment whether motor can run normally. The experimental results show that the method of combination vector machine and multi-scale principal component analysis is supported to diagnose motor fault. This offers a new method and idea to diagnose motor. This method improves the accuracy of motor fault detection and practical significance.

Abstract: The mechanical response of the composite structure in T650-35/PMR-15 aged at different temperatures was studied numerically. The time-dependent internal stresses in the composite ply and its constituents were computed during the creep process. In order to predict the effective properties of PMR-15/T650-35 composite ply in the temperature range [250-350°, the time-dependent mechanical properties of PMR-15 matrix determined experimentally [, were considered. The mechanical properties of the fibers do not experience any change due to the aging process in such a temperature range [2, . In order to achieve the computations, the visco-elastic Eshelby Kröner self-consistent model was used.

Abstract: The multi-scale features are the foundation of the inner laws existing in the multi-phase flow process. Computational fluid dynamics (CFD) method was used to study the inhomogeneous distribution and multi-scale features of the solid particles in DTB crystallizer. Suspension and flow field distributions of the particles under different stirring speed and different particle diameter were observed. The result showed: the higher the stirring speed, the smaller the particle diameter and the more homogeneous the suspension distribution. The inhomogeneous distribution of the particles in the crystallizer was mainly caused by vortex. The particle concentration was much lowers in the vortex center, meanwhile, the higher the stirring speed, the more the particles and vortex number, the vortex strength getting greater as well.

Abstract: The multi-scale method was applied to solve the multi-phase multi-scale problem in the industrial crystallization process. The fluid dynamics model was considering under the grid scale, and the population balance model was considering under subsystem scale. The macro model was used to interact with the environment. The crystallization process of potassium chloride was simulated by CFD and MATLAB. The result of the simulation shows the distribution of the supersaturation is strongly affected by the distribution of the suspended crystal volume fraction.