• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.1033-1042
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• 2020

Shale shaker which is one of the mud circulation systems is composed of a basket, a vibrator and a screen. Its purpose of a shale shaker is to induce drilling fluid to flow through a screen, transport solids across a screen surface, and discharge solids off the end of the screen. The new shale shaker for the on-shore drilling system is designed to be smaller than the original shale shaker which has the same capacity with the new on to enable to transport and to operate on the trailer. In this study, structural and vibrational analysis of shale shaker was carried out to evaluate the appropriateness of the design in terms of the structural stability.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.1050-1051
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• 2013

조선업종은 숙련공의 감소와 노동력 부족을 해결하기 위해 자동화와 기계화가 필요하다. 특히 조선용 핸드레일 제조공정은 표준화된 타 분야와 달리 자동화가 낙후되어 있다. 본 연구에서는 조선용 핸드레일 제작에 사용할 수 있는 평철 가공자동화시스템을 설계하였다. 시스템의 기구부는 절단공정의 효율성, 생산성, 안정성 등을 고려하여 설계하였고, CATIA 와 ANSYS를 사용하여 구조물의 안정성을 확인하였다. 시스템 제어부는 개방성과 확장성을 제공하는 PCNC 콘트롤러를 사용하였고, 터치스크린 방식의 화면 조작을 통해 시스템의 제어 및 모니터링을 할 수 있도록 구축하였다.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_2
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• pp.573-586
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• 2022

Corrosion can cause dangerous and expensive damage and failures of ship hulls and equipment. Therefore, it is necessary to maintain the vessel by periodic corrosion inspections. During visual inspection, many corrosion locations are inaccessible for many reasons, especially safety's point of view. Including subjective decisions of inspectors is one of the issues of visual inspection. Automation of visual inspection is tried by many pieces of research. In this study, we propose image preprocessing methods by image patch segmentation and thresholding. YOLOv5 was used as an object detection model after the image preprocessing. Finally, it was evaluated that corrosion detection performance using the proposed method was improved in terms of mean average precision.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.48.1-48.1
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• 2017

1669년 이민철(李敏哲, 1631~1715)은 천문시계를 제작하였다. 이민철의 천문시계는 2단의 수호(水壺)와 부차(浮車), 수차로 구성된 수격식 동력시스템에 의해 작동된다. 이 중 부차는 2단의 수호 중 아래쪽 단에 위치한 소호(小壺) 안에 설치되어 있다. 위쪽 단에 위치한 수호로부터 아래쪽 단에 위치한 소호로 물이 차면 부차가 떠오른다. 부력에 의해 떠오른 부차는 수차를 회전시킨다. 수차로부터 발생된 동력은 기륜을 통해 전달되어 태양운행장치와 달운행장치, 시보장치를 작동시켜 시간을 알려준다. 이민철 천문시계의 수격식 동력시스템은 부력으로 부차를 움직여 수차가 일정하게 회전도록 하였다. 이와 같이 수차운행에서 부력을 활용하는 방식은 조선 중기에 제작된 천문시계에서만 적용된 방식이다. 우리는 이민철 천문시계의 수격식 동력시스템에 관한 연구를 수행하여 전체적인 형태과 작동메커니즘에 대해 추정하였다. 아울러 연구 결과를 바탕으로 개념설계를 진행하였다.

• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.297-306
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• 2014

This paper analyzes Japan's consignment management of the Chosun Railway to the South Manchuria Railway. While Chosun Railway was entrusted, its management style differed significantly from that of Japan's direct management. After eight years of trust management, the direct management of Chosun Railway was returned to Japan. This of beyond border trust management is very rare. In addition, the management of Chosun Railway by South Manchuria Railway, which had an operation style similar to that of a private company, led to changes in Chosun Railway. This research analyzes the four key traits of South Manchuria Railway's consigned management. The first key trait is the initial Korean infrastructure and operation separation model. The second key trait is the international transportation and administration segregation. The third key trait is that it expanded the railway related businesses and led to the establishment of private railway companies. The fourth key trait is that the continental linked transportation was activated. Through analyses, it would be to create a comparative study of the resulting East Asian countries' operations. Furthermore, this research will in investigating the nature of Chosun Railway.

• Korean Journal of Microbiology
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• v.55 no.1
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• pp.67-68
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• 2019

Streptococcus constellatus is Gram-stain-positive, facultative anaerobic, and non-spore forming coccus. It is a member of normal flora of human oral cavity. S. constellatus KCOM 1039 was isolated from human postoperative maxillary cyst lesion. In this report, we present the draft genome sequence of S. constellatus KCOM 1039.

• Journal of Ocean Engineering and Technology
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• v.33 no.1
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• pp.92-97
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• 2019

The sea is stratified with water that has different densities because of pressure, temperature, and salinity. When conducting studies of internal waves in the ocean, the fluid is assumed to have layers that have discrete densities. This assumption is made because it is difficult to achieve layers that exhibit gradual changes in the density of the water. In this study, we used previous studies on ocean waves and their radiation issues in the density layer fluid to investigate the characteristics of internal waves in the ocean and their radiation patterns induced by a moving body in a stratified fluid. We also studied the difference in wave radiation between the density gradient layer and the discrete density layer. We found that the wave radiation patterns depended on the velocity of the moving body and the change in the density of the water. The crest apex shift phenomenon was observed in the density gradient in the layer of fluid.

• Journal of Ocean Engineering and Technology
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• v.33 no.3
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• pp.236-244
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• 2019

Internal waves occur at the interface between two layers caused by a seawater density difference. The internal waves generated by a body moving in a two-layer fluid are also related to the generation of surface waves because of their interaction. In these complex flow phenomena, the experimental measurements and experimental set-up for the wave patterns of the internal waves and surface waves are very difficult to perform in a laboratory. Therefore, studies have mainly been carried out using numerical analysis. However, model tests are needed to evaluate the accuracy of numerical models. In this study, the various experimental conditions were evaluated using CFD simulations before experiments to measure the wave patterns of the internal waves and surface waves in a stratified two-layer fluid. The numerical simulation conditions included variations in the densities of the fluids, depth of the two-layer fluid, and moving speed of the underwater body.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.2_2
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• pp.315-325
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• 2023

Recently, various dynamic risk analysis methods have been suggested for estimating the risk index by predicting the possibility of accidents and damage. It is necessary to maintain and support the safety system for responding to accidents by continuously updating the probability of accidents and the results of accidents, which are quantitative standards of ship risk. In this study, when a LNG leakage that may occur in the LN G Fuel Gas Supply System (FGSS) room during LN G bunkering operation, a reliability physical model was prepared by the change in monitoring data as physical parameters to estimate the accident probability. The scenario in which LNG leakage occur were configured with FT (Fault Tree), and the coefficient of the covariate model and Weibull distribution was estimated based on the monitoring data. The possibility of an LNG leakage, which is the top event of FT, was confirmed by changes in time and monitoring data. A method for estimating the LNG leakage based on the reliability physical analysis is proposed, which supports fast decision-making by identifying the potential LNG leakage at the accident.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.5
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• pp.895-905
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• 2023

Mud tanks used for storing and supplying mud in mud supply systems are essential to secure structural stability according to the mud loads inside the tank. In terms of structural stability of the mud tank can be ensured by increasing the thickness of the structure. However, increasing the thickness may cause a problem of increasing production costs. In addition, this increases the weight of the tank, which can cause problems with the trailer loading weight limitation during transportation. To satisfy both these problems and structural stability, the mud tank should be optimally designed. Therefore, this study conducted an optimum design in consideration of the load of the mud tank through the structural analysis and response surface optimization method in ANSYS.