International Journal of Applied Electromagnetics and Mechanics - Volume 15, issue 1-4

Authors: Li, Hui | xTakei, Yoshifuru | Saito, Yoshifuru | Horii, Kiyoshi

Article Type: Research Article

Abstract: Our motive of this study is to develop an application of the wavelet packet to PIV image compression processing in order to improve the spatial resolution and reliability furthermore. It was found that the reconstructed PIV image with a lower compression ratio might emphasize particle edges at a relatively high spatial resolution. The reconstructed PIV image with a higher compression ratio may display the large-scale motion of particles and may deduce noisy. In this study, the …relative error of the wavelet packet image compression technique was lower than that of the standard wavelet image compression technique. The higher compression ratio of 64:1 can be realized without losing significant flow information in PIV processing. It could say that the wavelet packet could provide a better compression performance than the standard wavelet image compression technique when compressing PIV images. Show more

DOI: 10.3233/JAE-2002-471

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 383-392, 2002

Authors: Li, Hui | Zhou, Yu | Takei, Masahiro | Saito, Yoshifuru | Horii, Kiyoshi

Article Type: Research Article

Abstract: The vector wavelet multi-resolution technique based on the orthogonal wavelet transform was used to analyze the velocity vector data that were simultaneously obtained by sixteen X-wires in the turbulent near-wake of a circular cylinder at different streamwise positions. The instantaneous velocity vector field is decomposed into the multi-scale structures, and its sectional streamline of various scales is displayed. The large-scale structures in the plane of mean shear are consistent with the well-known Kármán vortices. The …structures that correspond to the saddle region between Kármán vortices are identified with the rib-like structures. Even smaller scale structures are also observed. As increasing x/d, the decay of vortical structure and rib-like structure are observed. The topologies of Reynolds stress and RMS vorticity associated with the multi-scale structures are discussed at different downstream positions. It is found that the most significant contribution to Reynolds stress comes from the frequency components of f ≤ 219 Hz at x/d = 20. However, the contribution to Reynolds stress coming from the intermediate-scale structure becomes weak at x/d = 40. The RMS vorticity components of f = 875 Hz is the largest among all components. Show more

DOI: 10.3233/JAE-2002-472

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 393-402, 2002

Authors: Marinova, Iliana | Endo, Hisashi | Hayano, Seiji | Saito, Yoshifuru

Article Type: Research Article

Abstract: The purpose of this article is to apply an inverse approach for image reconstruction during electromagnetic field visualization. The reconstruction of the images is formulated as an inverse problem. For the image color model, the Poisson equation with open boundary condition is imposed. The color source densities have been evaluated from the color distributions for electromagnetic field data set. The Generalized Vector Sampled Pattern Matching method is applied to solve an ill posed linear system of …equations for the corresponding inverse problem. The new color distributions are generated and visualized using the obtained color source densities. With the proposed inverse approach the dark parts of the images can be reduced or completely removed. This article collects several examples for electromagnetic field visualization of the most commonly used sensor coil. Show more

DOI: 10.3233/JAE-2002-483

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 403-408, 2002

Authors: Endo, Hisashi | Hayano, Seiji | Fujikura, Masahiro | Mogi, Hisashi | Kaido, Chikara | Saito, Yoshifuru

Article Type: Research Article

Abstract: This paper proposes a visualizing methodology of iron loss generation in a magnetic material using its visualized domain images, i.e., SEM, Kerr and Faraday effects. Based on the differential equations for dynamic image, the material behavior is visualized. The state transition matrix of the Helmholtz equation, for which is derived from a series of distinct visualized domain images representing magnetized state. This makes it possible to visualize the magnetizing mechanism as well as iron loss generation. …In the present paper, visualization of iron loss generation on a grain-oriented electrical steel sheet is worked out using a set of SEM images. As a result of our image analysis, magnetization curves at the particular points can be estimated. Show more

DOI: 10.3233/JAE-2002-474

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 409-416, 2002

Authors: Noguchi, So | Yamashita, Hideo | Matsubayashi, Yutaka | Okayama, Eiji

Article Type: Research Article

Abstract: A new interactive visualization system for education and design purposes in 2D electromagnetics is proposed. The proposed system using numerically computational results for several typical model configurations can display interactively electromagnetic field phenomena for any other model configuration bounded with the previously computed ones. It uses simple bilinear interpolation techniques in order to provide fast interactive display. This visualization system can be used for design purposes of problems with different model configurations …and as an educational tool for teaching electromagnetics. Show more

DOI: 10.3233/JAE-2002-482

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 417-422, 2002

Authors: Takei, Masahiro | Li, Hui | Ochi, Mitsuaki | Saito, Yoshifuru | Horii, Kiyoshi

Article Type: Research Article

Abstract: A concept to extract a feature of solid-air two-phase flow in a pipeline has been launched with a combination of a capacitance-computed tomography and wavelets transform. With this concept, particle distribution images obtained by CT are transformed with discrete wavelets multiresolution. As a result, in the case of low open area ratios of the pipe cross-section, high particle densities are shown in secondary dominant levels as well as a substantial space level. The high value in …the secondary level resulted from inhomogeneous density due to collision between particles. Show more

DOI: 10.3233/JAE-2002-470

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 423-430, 2002

Authors: Terasawa, Y. | Fujikado, T. | Yagi, T.

Article Type: Research Article

Abstract: In developing a visual prosthesis, it is essential for us to determine its specifications which meet the minimal needs in daily lives of patients. For that purpose, we have proposed a prosthetic vision simulator which enables us to experience prosthetic vision in the virtual space. This time, we applied this system to quantitative evaluation of the reading ability. Experimental results suggested that the electric current intensity in stimulation has small effects to the reading ability.

DOI: 10.3233/JAE-2002-484

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 431-436, 2002

Authors: Yabunami, H. | Hayano, S. | Saito, Y.

Article Type: Research Article

Abstract: As is well known, conventional magnetic circuit theory makes it possible to analyze the three-dimensional magnetic fields, even though its theoretical background is based on the engineering experiences. On the other side, finite elements have a firm theoretical background but it is too expensive to implement the three-dimensional analysis. In order to carry out the three-dimensional magnetic field analysis in a most efficient manner, we propose the theory of modern magnet circuit based on finite elements. …This makes it possible to implement the three-dimensional magnetic field computation in a quite efficient manner. A simple example demonstrates not only the usefulness but also efficiency of our new methodology. Show more

DOI: 10.3233/JAE-2002-476

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 15, no. 1-4, pp. 437-442, 2002