• Plant Journal
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• v.11 no.2
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• pp.39-44
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• 2015

According to a research that is based on a previous study, But in a different way, This study shows fault diagnosis of Induction motor bearing which runs in coal-fired power plant industries on Desulfurization absorber agitator using Spectrum analysis of Stator Current and visual inspection. As a result of harmonic content analysis of stator current spectrum, It was possible to detect ball and outer race fault frequency. The comparison in the context of this experiment proves that the amplitude of faulty frequency is increased in three times at a fault in ball and in outer race. Spectrum analysis of stator current can be used to detect the presence of a fault condition as well as experiment in faulty bearings, besides early fault detection in bearings can prevent unexpected power generation loss and emergency maintenance cost.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.347-352
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• 2012

In this paper, an 2D spatial-map construction for workers identification and avoidance of AGV using the detection scheme of the spatial coordinates based on stereo camera is proposed. In the proposed system, face area of a moving person is detected from a left image among the stereo image pairs by using the YCbCr color model and its center coordinates are computed by using the centroid method and then using these data, the stereo camera embedded on the mobile robot can be controlled for tracking the moving target in real-time. Moreover, using the disparity map obtained from the left and right images captured by the tracking-controlled stereo camera system and the perspective transformation between a 3-D scene and an image plane, depth map can be detected. From some experiments on AGV driving with 240 frames of the stereo images, it is analyzed that error ratio between the calculated and measured values of the worker's width is found to be very low value of 2.19% and 1.52% on average.

• International Journal of Highway Engineering
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• v.18 no.6
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• pp.61-67
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• 2016

OBJECTIVES : The objective of this study is to detect road cavities using multi-channel 3D ground penetrating radar (GPR) tests owned by the Seoul Metropolitan Government. METHODS : Ground-penetrating radar tests were conducted on 204 road-cavity test sections, and the GPR signal patterns were analyzed to classify signal shape, amplitude, and phase change. RESULTS : The shapes of the GPR signals of road-cavity sections were circular or ellipsoidal in the plane image of the 3D GPR results. However, in the longitudinal or transverse direction, the signals showed mostly unsymmetrical (or symmetrical in some cases) parabolic shapes. The amplitude of the GPR signals reflected from road cavities was stronger than that from other media. No particular pattern of the amplitude was found because of nonuniform medium and utilities nearby. In many cases where road cavities extended to the bottom of the asphalt concrete layer, the signal phase was reversed. However, no reversed signal was found in subbase, subgrade, or deeper locations. CONCLUSIONS : For detecting road cavities, the results of the GPR signal-pattern analysis can be applied. In general, GPR signals on road cavity-sections had unsymmetrical hyperbolic shape, relatively stronger amplitude, and reversed phase. Owing to the uncertainties of underground materials, utilities, and road cavities, GPR signal interpretation was difficult. To perform quantitative analysis for road cavity detection, additional GPR tests and signal pattern analysis need to be conducted.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1546-1551
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• 2004

The laser Doppler technique is well-established as a velocity measurement technique of high precision for flow velocity. Recently, the laser Doppler technique has also been used to measure acceleration of fluid particles. Acceleration is interesting from a fluid mechanics point of view, since the Navier Stokes equations, specifically the left-hand-side, are formulated in terms of fluid acceleration. Further, there are several avenues to estimating the dissipation rate using the acceleration. However such measurements place additional demands on the design of the optical system; in particular fringe non-uniformity must be held below about 0.0001 to avoid systematic errors. Relations expressing fringe divergence as a function of the optical parameters of the system have been given in the literature; however, direct use of these formulae to minimize fringe divergence lead either to very large measurement volumes or to extremely high intersection angles. This dilemma can be resolved by using an off-axis receiving arrangement, in which the measurement volume is truncated by a pinhole in front of the detection plane. In the present study an optical design study is performed for optimizing laser Doppler systems for fluid acceleration measurements. This is followed by laboratory validation using a round free jet and a stagnation flow, two flows in which either fluid acceleration has been previously measured or in which the acceleration is known analytically. A 90 degree off-axis receiving angle is used with a pinhole or a slit.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.194-204
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• 2000

Echocardiography was performed to obtain the optimal planes for diagnosis of canine heartworm disease in 11 dogs. Imaging planes were taken the left ventricular outflow tract long-axis view, 4-chamber long-axis view, chordae tendineae level short-axis view and modified pulmonary arteries level short-axis view in the right parasternal window, and aptical 4-chamber long-axis view in hte left parasternal window. After echocaridography, the pulmonary artery valve pat was ligated with double 1-0 silk under the general anesthesia to prevent heartworm moving from pulmonary artery to right ventricle. The dogs were euthanized and examained for heartworms in heart and great vessels. Many adult heartworms were identified ultrasonographically within main pulmonary artery, bifurcation of pulmonary artery and right pulmonary artery, but not identified within right ventricle and atrium. At necropsy, adult heartworms were mainly found in pulmonary artery in 11 days, and also found in right ventricular outflow tract and right ventricle in 2 of 11 dogs. The modified pulmonary arteries level short-axis view was the best imaging plane for identifiying heartworms because the main pulmonary artery, branches of pulmonary artery and right pulmonary artery could be showed. The aortic root internal dimension (AOID) and right pulmonary atery internal dimension (RPAID) were measured from the modified pulmonary ateries level short-axis view and left ventricular outflow tract long-axis view. The RPAID and RPAID/AOID was higher in heartworm infected dogs than normal Korea Jin-do dogs in modified pulmonary arteries level short-axis view, and the AOID, RPAID and RPIAID/AOID was higher than in left ventricular outflow tract long-axis view, respectively. These results indicate that the pulmonary arteries were the major habitat of adult heartworm in canine heartworm disease and the modified pulmonary arteries level short-axis view was the best imaging planes for identifying heartworms because the main pulmonary arteries could be showed. Therefore the modified pulmonary arteries level short-axis view can be used for diagnosing heartworm disease and for monitoring dilation of pulmonary artery.

• Journal of the Korea Computer Graphics Society
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• v.23 no.1
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• pp.39-48
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• 2017

We present penetration depth (PD) computation algorithms using explicit Minkowski sum construction ($PD_e$) and implicit Minkowski sum construction ($PD_i$). Minkowski sum construction is the most time consuming part in fast PD computation. In order to address this issue, we find a candidate solution using a centroid difference and motion coherence. Then, $PD_e$ constructs or updates partial Minkowski sum around the candidate solution. In contrast, $PD_i$ constructs only a tangent plane to the Minkowski sums iteratively. In practice, our algorithms can compute PD for complicated models consisting of thousands of triangles in a few milli-seconds. We also discuss the benefits of using different construction of Minkowski sums in the context of PD.

• Journal of Korea Multimedia Society
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• v.17 no.2
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• pp.208-217
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• 2014

This paper propose an adaptive control of symmetry contribution based generalized symmetry transform. which can be controlled symmetry contribution according to the intensity orientation of two pixels. In the proposed method, we define the C-D(convergent and divergent)plane which represents convergence and divergence region of gradient pairs. and used the gaussian phase wight function, with respect to the distance from the gradient pair to an extreme point, in calculating the symmetry contribution. The proposed method can be detect the object more efficiently by adaptive controlling the cut-off frequency of the gaussian phase wight function. To evaluate a performance of the proposed method, we compare the proposed method and conventional GST method in various images including IR image. we prove that the proposed method have better performance in object detection.

• Korean Journal of Remote Sensing
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• v.27 no.1
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• pp.9-15
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• 2011

Since PAN(panchromatic) and MS(multispectral) imagery of pushbroom scanner have the offset between PAN and MS CCD(charge coupled device) in the focal plane, PAN and MS images are acquired at different time and angle. Since clouds are fast moving objects, they should lead mis-registration problem with wrong matching points on clouds. The registration of cloudy imagery to recognize and remove the contamination of clouds can be categorized into three classes: (1) cloud is considered as nose and removed (2) employing multi-spectral imagery (3) using multi-temporal imagery. In this paper, method (1) and (3) are implemented and analysed with cloudy pushbroom scanner images.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.2
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• pp.169-176
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• 2001

In modern industry, the accuracy and the sulfate-finish requirements for machined parts have been becoming ever more stringent. In addition, the measurement and understanding of surface topography is rapidly attracting the attention of the physicist and chemist as well as the engineer. Optical measuring method is used in vibration measurement, crack and defect detection with the advent of opto-mechatronics, and it is expected to play an important role in surface topography. In this study, the principle of confocal microscope is described, and the advanced 3-D surface measuring system that has better performance than the traditional confocal microscope is developed. Suitable fixtures arc developed and integrated with the computer system for generating 3-D surface and form data. Software for data acquisition and analysis of various parameters in surface geometrical features has been developed.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.397-402
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• 2018

The study best image for diagnosis of fracture, dislocation and unilateral degenerative arthritis of the Sacroiliac joint, this study was performed to obtain the best image of the joint space of the hip joint by giving angle change to the pelvis phantom and the x-ray tube. I received evaluation. The results of the Receiver Operating Characteristic that in the case of simple photographs for the detection of joint arthritis and degenerative arthritis in the prone position, the photograph taken in the prone position raises the buttocks of the opposite side of the test by $25^{\circ}{\sim}30^{\circ}$ and the x-ray tube is perpendicular to the sagittal plane passing 2.5 cm inward from the thorny vertebra In the lying position, lift the Sacroiliac joint of the test side by $25^{\circ}{\sim}30^{\circ}$, and take a $5^{\circ}$ angle of the x-ray tube angle toward the foot toward the center of the upper bruch spine from it will be helpful to diagnose arthritis. the center of the upper bruch spine to the side of the ankle joints in the transverse direction And posterior direction, it will be helpful to diagnose arthritis.