• Journal of the Korean Magnetics Society
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• v.7 no.3
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• pp.134-139
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• 1997

Magneto-impedence (MI) were measured in amorphous $Co_{66}Fe_4NiB_{14} Si_{15}$ ribbons at 100 kHz as a function of the angle from ribbon axis. The samples were prepared using etching method, with the angle deviated from ribbon axis, 0$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$, 60$^{\circ}$ and 90$^{\circ}$. The MI measured in 60$^{\circ}$ sample increased with the increasing magnetic fields. The dip in profile appears at H = 0 above the angle of 30$^{\circ}$. The maximum values of MI and their dips are increased with the cutting angle, but the maximum value of MI decreased at 90$^{\circ}$. The increase of MI with the angle was analyzed in terms of the transverse magnetic permeability.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.10
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• pp.1294-1304
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• 1995

In this paper, a method has been proposed for the fully automatic detection of left ventricular endocardial boundary in B-mode short axis echocardiography without manual intervention by human operator. The proposed method makes use of the weighted model that approximates to endocardium and incomplete edge information for echocardiography. Therefore, this method is more effective than boundary detection by only edge information. The implementation of this method is as follows. First, the proposed algorithms are used in order to detect the approximate boundary, then a weighted model with the approximate boundary is constructed. Finally, the cavity center of the left ventricle performing the Hough transform with the weighted model and edge image can be found automatically, and then the endocardial boundary using detected center, original image, weighted model, and edge image can be detected. validations of this method with experimental results on echo image of dog's heart and clinical echocardiography is verified.

• Applied Biological Chemistry
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• v.27 no.2
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• pp.129-134
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• 1984

Change of protein component in soybean sprout grown at four temperatures was investigated by polyacrylamide gel electrophoresis. Main bands were identified using purified seed globulins. Electrophoretogram showed 5 main bands (a. b, c, d, and p) and 10 minor bands in seed and maximum number (19) of bands (8 main band including 0 and 11 minor) at 4th day after germination in cotyledon. All bands appeared in axis protein but resolution was poor. In cotyledon, a component (most rapidly) and b+c+d component decreased while o+p component and other minor components were increased at 6th day and decreased thereafter. In axis all components increased rapidly, especially in minor components and b+c+d component. High growing temperature accelerated decrease in cotyledon and increase in axis of protein, especially for 11S. The a component was identified as 7S, b+c+d as 11S and o+p as 2S globulin.

• Progress in Superconductivity
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• v.9 no.1
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• pp.5-10
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• 2007

We prepared four different $MgB_2$ films on $Al_2O_3$ by hybrid physical chemical vapor deposition method with thicknesses ranging from $0.65\;{\mu}m$ to $1.2\;{\mu}m$. X-ray diffraction patterns confirm that all the $MgB_2$ films are c-axis oriented perpendicular to $Al_2O_3$ substrates. The superconducting onset temperature of $MgB_2$ films were between 39.39K and 40.72K. The residual resistivity ratio of the $MgB_2$ films was in the range between 3.13 and 37.3. We measured the angle dependence of critical current density ($J_c$) and resistivity, and determined the upper critical field ($H_{c2}$) from the temperature dependence of the resistivity curves. The anisotropy ratios defined as the ratio of the $H_{c2}$ parallel to the ab-plane to that perpendicular to the ab-plane were in the range of 2.13 to 4.5 and were increased as the temperature was decreased. Some samples showed increase of $J_c$ and decrease of resistivity when a magnetic field in applied parallel to the c-axis. We interpret this angle dependence in terms of enhanced flux pinning due to columnar growth of $MgB_2$ along the c-axis.

• IE interfaces
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• v.9 no.2
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• pp.129-141
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• 1996

Recently, the tire mold of a passenger car is made almost via aluminum casting, and it is necessary to prepare a master model of the tire for the casting. Because of the geometrical feature of tire, as well known, the master model must be machined by a 5-axis NC machine. The paper proposes a procedure to model and machine the master model. The approach includes (a) transformation of 2D drawing of tire into 3D geometry, (b) modeling surfaces of tire, and (c) inverse kinematics of a 5-axis NC machine. An implementation of the proposed procedure is also presented.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.175-180
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• 1990

Rotational-free-surface (RFS) is a special type of free surface whose two boundaries coincide. For NC machining of PFS, a rotational axis as well as three Cartesian axes are required. In this paper, we develop a four-axis CAM module consisting of: a) Geometric modeling of RFS, b) CL-data generation, and c) Graphic simulation of machining operation. To test the validity and effectiveness of the developed module, several test cuts are made with Bridgeport CNC milling machine and compared with the graphic simulation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.157-158
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• 2010

• Korean Journal of Remote Sensing
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• v.9 no.2
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• pp.7-19
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• 1993

In stereo vision, when we use two parallel axis images, small portion of object is contained and B/H(Base-line to Height) ratio is limited due to the size of object and depth information is inaccurate. To overcome these difficulities we take a non-parallel axis image which is rotated $\theta$ about y-axis and match other parallel-axis image. Epipolar lines of non-parallel axis image are not same as those of parallel-axis image and we can't match these two images directly. In this paper, we transform the non-parallel axis image geometrically with camera parameters, whose epipolar lines are alingned parallel. NCC(Normalized Cross Correlation) is used as match measure, area-based matching technique is used find correspondence and 9$\times$9 window size is used, which is chosen experimentally. Focal length which is necessary to get depth information of given object is calculated with least-squares method by CCD camera characteristics and lenz property. Finally, we select 30 test points from given object whose elevation is varied to 150 mm, calculate heights and know that height RMS error is 7.9 mm.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.2
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• pp.53-60
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• 2003

This paper deals with steady-state analysis of a single-phase line-start permanent magnet synchronous motor. In order to analyze the steady-state characteristics, the asymmetric single-phase line-start synchronous motor is converted to the symmetric two-phase synchronous motor, that is, the asymmetric magnetic field is separated from the positive and the negative symmetric components using symmetrical-component theory. The analysis method of the synchronous motor on the d-q axis coordinates is used for the positive component and the equivalent circuit of the induction motor is applied for the negative component analysis. Moreover, d-q axis inductance considering current phase angle is applied to positive component analysis for precise characteristic analysis. In order to validate the proposed analysis method, the analysis results are compared with the experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.7
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• pp.380-388
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• 2006

In this paper, a novel control algorithm to minimize the power loss of the induction generator for wind power generation system is presented. The proposed method is based on the flux level reduction, where the flux level is computed from the machine model for the optimum d-axis current of the generator. For the vector-controlled induction generator, the d-axis current controls the excitation level in order to minimize the generator loss while the q-axis current controls the generator torque, by which the speed of the induction generator is controlled according to the variation of the wind speed in order to produce the maximum output power. Wind turbine simulator has been implemented in laboratory to validate the theoretical development. The experimental results show that the loss minimization process is more effective at low wind speed and that the percent of power loss saving can approach to 25%. Experimental results are shown to verify the validity of the proposed scheme.