• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.807-812
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• 1997

For an equivalent uniform soil model to multiple-layered soil structure, ground depth, which is used in the calculation of equivalent resistivity, should be varied according to the size of grounding area. In case of 150 kV substation grounding design, 15 m of ground depth has been used and 25 m for 345 kV, But applying these ground depths can lead to errors in grounding resistance calculation, and these errors are coming from the poor representation of those depths to real soil resistivities. In this paper, the soil resistivity measurement techniques by Wenner method and grounding resistance calculation results by computer simulation were presented. Case studies contain the area from 3,000 to $30,000\;m^2$ and measuring space from of m to $100{\sim}250\;m$, Based of the computation results, 50 m, 60 m and 80 m of ground depth for less than 30, 40 and 70 m of equivalent hemispherical radius were proposed respectively.

• Journal of Welding and Joining
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• v.29 no.4
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• pp.67-72
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• 2011

The proportion of the welding in the production process of machinery, buildings and marine structures is increasing and the joining are mainly conducted by butt and fillet weld. In the case of fillet weld, the shape of structures is complicated depending on the constraint on the geometry of the structures, therefore, the full penetration is mostly difficult. Accordingly, it is necessary to establish safe and economical criteria of design of the structures through the strength based on the penetration state of the fillet weld. Patterns of fatigue failure in cruciform fillet weld jont appear in the form of the root, toe and mixed failure. In the case of toe and mixed failure, the fatigue strength is higher than root failure. Therefore, we have to make the enough depth of penetration or perform the welding work through improving the fatigue strength of cruciform joints in welded structures. So it is necessary to optimize the penetrated depth in the range of the possible mixed failure and find the way in the cost-effective design to lessen the amount of the welding work.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.47-53
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• 2006

The purpose of this study was to investigate the significant characteristics in spray of industrial etch-nozzle for the design of process. The experiment was carried out with different spray pressure and industrial nozzle in wet etch. The characteristics of liquid spray, such as axial velocity and sauter mean diameter measurements were obtained by PDA. And impact force was calculated from spray characteristics. It was found that the fluid with higher spray pressure resulted in the smaller SMD and the higher droplet velocity and impact force. The depth of etch was increased in case of high spray pressure. In the case of injection angle oscillated between $20^{\circ}$, the result indicated constant effect of etch. The correlation between the spray characteristics and etch ones were analyzed. The depth of etch had good positive correlation with axial velocity and impact force. The result clearly shows that the characteristics in wet etch are strongly related to the spray characteristics with process.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.5
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• pp.169-175
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• 2022

Scour in a flow field affected by waves, such as river estuaries or shallow waters, is more difficult to predict than scour in a currents. The main issue in predicting the scour around circular files, such as undersea bridges, is the maximum scour depth and the point of occurrence. In the case of two or more adjacent circular piles, the location and depth of maximum scour according to the spacing between piles and the arrangement method show a lot of difference compared to the case of a single pile. In this paper, the KC number are calculated as dimensionless variables representing the strength of the flow. And the correlation between pile gap size and relative scour depth was analyzed.

• Journal of Korea Water Resources Association
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• v.38 no.7 s.156
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• pp.527-535
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• 2005

The computation of normal depth is very important for the design of channel and the analysis of water flow. Drainage pipe generally has the shape of curvature like circular or U-type, which is different from artificial triangular or rectangular channel. In this case, the computation of normal depth or the derivation of equations is very difficult because the change of hydraulic radius and area versus depth is not simple. If the ratio of the area to the diameter, or the hydraulic radius to the diameter of pipe is expressed as the water depth to the diameter of pipe by power law, however, the process of computing normal depth becomes relatively simple, and explicit equations can be obtained. In the present study, developed are the explicit normal depth equations for circular and U-type pipes, and the normal depth equation associated with Hagen (Manning) equation and friction factor equation of smooth turbulent flow by power law is also proposed because of its wide usage in engineering design.

• Journal of the Korea Society of Computer and Information
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• v.17 no.7
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• pp.53-65
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• 2012

Existing method of creating Stereoscopy image, creates viewpoint image from the left and right by shooting one object with 2 lens in certain distance. However, in case of 3-D TV using Stereoscopy camera, the necessity to transmit 2 viewpoint images from the left and right simultaneously, increases the amount of bandwidth. Various and more effective alternatives are under discussion. Among the alternatives, DIBR(Depth Image Based Rendering) creates viewpoint images from the left and right using one image and its Depth information, thus decreasing the amount of transmitted bandwidth. For this reason, there have been various studies on Algorithm to create DIBR Image in existing Static Scene. In this paper, I would like to suggest Gaussian Hole-filling solution, which utilizes reverse-depth image to fill the hole naturally, while minimizing distortion of background. In addition, we have analyzed the effectiveness of each Algorithm by comparing and calculating its functions.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.3
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• pp.29-35
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• 2010

This paper discusses a method that can enhance the exactness of depth estimation of an image by PCA(Principle Component Analysis) based on feature reduction through learning algorithm. In estimation of the depth of an image, hyphen such as energy of pixels and gradient of them are found, those selves and their relationship are used for depth estimation. In such a case, many features are obtained by various filter operations. If all of the obtained features are equally used without considering their contribution for depth estimation, The efficiency of depth estimation goes down. This paper proposes a method that can enhance the exactness of depth estimation of an image and its processing speed is considered as the contribution factor through PCA. The experiment shows that the proposed method(30% of an feature vector) is more exact(average 0.4%, maximum 2.5%) than using all of an image data in depth estimation.

• Journal of the Institute of Convergence Signal Processing
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• v.18 no.2
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• pp.68-75
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• 2017

This study deals with a color-based tracking method of a moving object effectively in case that the color of the moving object is same as or similar to that of background. The CamShift algorithm, which is the representative color-based tracking method, shows unstable tracking when the color of moving objects exists in the background. In order to overcome the drawback, this paper proposes the CamShift algorithm merged with depth information of the object. Depth information can be obtained from Kinect device which measures the distance information of all pixels in an image. Experimental result shows that the proposed tracking method, the Camshift merged with depth information of the tracking object, makes up for the unstable tracking of the existing CamShift algorithm and also shows improved tracking performance in comparison with only CamShift algorithm.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.89-96
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• 2016

The High Efficiency Video Coding (MPEG-H HEVC/ITU-T H.265) is the newest video coding standard which has the quadtree-structured coding unit (CU). The quadtree-structure splits a CU adaptively, and its optimum CU depth can be determined by rate-distortion optimization. Such HEVC encoding requires very high computational complexity for CU depth decision. Motivated that the blob detection, which is a well-known algorithm in computer vision, detects keypoints in pictures and decision of CU depth needs to consider high frequency energy distribution, in this paper, we propose to utilize these keypoints for fast CU depth decision. Experimental results show that 20% encoding time can be saved with only slightly increasing BDBR by 0.45% on all intra case.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.2
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• pp.65-71
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• 2022

In the case of Mobile PKG Trend is in a situation where a decrease in Mold Top Margin is inevitable due to its miniaturization and high capacity product requirements. However, conventional laser marking technology has an average depth of deep, and when applied to narrow top margin products, PKG strength is expected to decrease due to overlapping processing, and reliability is reduced due to poor quality such as chip damage due to laser exposure. Therefore, we have secured the technology through research on low-depth laser marking solutions that can accommodate narrow top margin products. As a result of the evaluation of applicable technology application for PKG development products, it was verified that the marking depth decreased by 67% reduced and the PKG strength increased by 12%. Furthermore, the quality verification of Laser Damage that can occur through PKG Mechanical analysis was performed, and no Chip Damage defects were found. This ensured the stability of mass production application quality.