• Journal of Surface Science and Engineering
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• v.52 no.1
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• pp.23-29
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• 2019

Electrolytic corrosion of the ship's hull can be occurred due to stray current during welding work using shore power and electrical leakage using shore power supply. The electrolytic corrosion characteristics were investigated for Al5083-H321 through potentiodynamic polarization and galvanostatic corrosion test in natural seawater. Experiments of electrolytic corrosion were tested at various current densities ranging from $0.01mA/cm^2$ to $10mA/cm^2$ for 30 minutes, and at various applied time ranging from 60 to 240 minutes. Evaluation of electrolytic corrosion was carried out by Tafel extrapolation, weight loss, surface analysis after the experiment. In the electrolytic corrosion characteristics of Al5083-H321 as the current density increased, the surface damage tended to proportionally increase. In the current density of $0.01mA/cm^2$ for a applied long time, the damage tended to grow on the surface. In the case of $10mA/cm^2$ current density for a applied long time, the damage progressed to the depth direction of the surface, and the amount of weight loss per hour increased to 4 mg/hr.

• Annual Conference of KIPS
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• 2023.05a
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• pp.237-238
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• 2023

코로나 19 로 대면이 아닌 비대면이 일상이 되며 공공기관과 기업들이 사용자에게 보내는 메시지의 양이 증가하였다. 이에 따라 공공기관을 사칭하는 메신저피싱이 증가하였다. 본 논문에서는 OpenAPI 데이터를 활용한 메신저 위험 url 감지 시스템의 설계를 제시한다. 메신저피싱으로 인한 금전 피해 및 개인정보 탈취를 예방하기 위해 메시지의 포함된 피싱 url 과 기관, 기업의 사전 안전 인증을 통한 안전 url 을 구분한다. 이를 통해 사용자에게 안전하고 쾌적한 인터넷을 제공한다. 향후, 제안하는 시스템의 현실적인 검증과 성능 평가가 필요하다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.883-889
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• 2021

The South Korean fishing industry is experiencing a rapid growth owing to an increase in its leisure-fishing population. Consequently, fishing boats weighing 9-10 [ton] have also been increasing. Current fishing boats operate their essential equipment by switching their engines with batteries to reduce the cost of gas and engine noise. However, stranding incidents have been increasingly recorded annually, in which boats fail to start owing to discharged batteries, and these incidents can lead to serious casualties. This study proposes the installation of a solar auxiliary power system to safeguard fishing boats, particularly those weighing between 9-10 [ton]. The feasibility of securing space for the solar auxiliary power of boats under consideration was verified. To examine the application of solar power, this study calculates the load necessary to operate it for fishing and models such a system using an electricity analysis program The modeled system, which applies the monthly horizontal solar insolation, validated the adoption of a solar auxiliary power in fishing boats.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.839-845
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• 2021

In this study, it shows the efficiency of each refrigerant through simulation method for ORC (Organic Rankine Cycle) power generation that converts waste heat discarded by ship exhaust into electricity for the purpose of reducing CO₂ emission and increasing ship waste heat recovery. by Simulation was performed with waste heat from the exhaust gas which is relatively high temperature and cooling sea water which is relatively low temperature from ships. As a result of the sea water cooling ORC power generating system, efficiency of the working fluid with R717 is highest as a 2.86 % and the next working fluid is R152a, R134a, R143a and R125a.

• Corrosion Science and Technology
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• v.20 no.6
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• pp.403-411
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• 2021

In this study, the reliability of a commercial ER-type corrosion sensor was evaluated under an accelerated corrosion environment to verify its suitability for application in monitoring of ship's seawater piping system. A closed-loop pump piping testbed was designed and constructed to compare the wall thickness reduction of the pipe and the response from the sensor. The sensor was attached inside the pipe near the outlet of the pump that was exposed to a 3.5% NaCl solution with or without copper accelerated acetic acid (CASS). The results demonstrated that the presence of CASS significantly increased the corrosivity of the solution as well as the thickness reduction of the pipe, as expected. On the other hand, the corrosion products formed by the solution with CASS were thicker compared with those without CASS. The sensor response to temperature variation was found to be a clear linear relationship for the solution without CASS but there was a non-linear relationship where CASS was present.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.675-682
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• 2021

Fire accidents on land and at sea can cause serious casualties; specifically, owing to the nature of marine plants and ships, the mortality rate at sea from suffocation in confined spaces is significantly higher than that on land. To prevent such cases of asphyxiation, it is essential to install ventilation fans that can outwardly direct these toxic gases from fires; however, considering the scale of marine fires, the installation of large ventilation fans is not easy owing to the nature of marine structures. Therefore, in this study, we developed a new concept for fire safety technology to control toxic gases generated by fires from applied direct current (DC) electric fields. In the event of a fire, most flames contain large numbers of positive and negative charges from chemi-ionization, which generates an "ionic wind" by Lorentz forces through the applied electric fields. Using these ionic winds, an experimental study was performed to artificially control the fire smoke caused by burning paper and styrofoam, which are commonly used as insulation materials in general buildings and ships. The experiments showed that a fire smoke could be artificially controlled by applying a DC voltage in excess of ±5 kV and that relatively effective control was possible by applying a negative voltage rather than a positive voltage.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.1
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• pp.193-199
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• 2023

In this study, an analysis was conducted to analyze the structural stability of the piezoelectric power generation module and to determine the optimal burying hole interval for concrete, the installation site of the power generation module. A piezoelectric element refers to a functional ceramic having a piezoelectric direct effect that converts mechanical energy into electrical energy and a piezoelectric reverse effect. In the analysis of the piezoelectric power generation module, the load condition was applied with about 16 tons and a total of 10 wheels in consideration of the container trailer. The purpose was to evaluate the stability of major components of the piezoelectric power generation module through finite element analysis. In order to determine the optimal burying location of the concrete ground for burying the piezoelectric power generation module, the stability of the ground structure according to the distance of the holes was determined. As a result of the analysis, the maximum stress of the piezoelectric power generation module was generated in the support spring, showing a stress of about 276.7 MPa. It was found that the spacing of holes for embedding the piezoelectric power generation module should be set to a minimum of 100 mm or more.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.659-665
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• 2023

The exciter of a ship generator adjusts the magnetic flux through excitation current control to maintain the output terminal voltage constant. The voltage controller inside the exciter typically uses a proportional integral control method. however, the response characteristics determined by the gain and time constant produce unwanted output owing to an inappropriate setting value that can reduce the quality and stability of power within the ship. In this study, a neural network circuit is learned using stable input/output data that can be obtained through the AC4A type exciter model provided by IEEE, and the simulation is performed by replacing the existing proportional integral control type voltage controller with the learned neural network circuit controller. Consequently, overshooting was improved by up to 9.63% compared with that of the previous model, and excellence in stable response characteristics was confirmed.

• Annual Conference of KIPS
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• 2009.11a
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• pp.959-960
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• 2009

재해 및 재난에 의한 위험은 비록 그 발생빈도는 낮지만 직접적인 충격 및 그 파급효과가 매우 크다. 특히 금융기관은 정보시스템에 대한 의존도가 높고 국내 및 세계경제에 매우 중요한 역할을 하고 있어 업무연속성(Business Continuity)에 대한 관심이 크게 증대되고 있다. 본 논문에서는 평상시 위기상황 발생시에 대한 정확한 문제의식 파악과 더불어 유사시 발생할 수 있는 업무 중단에 대비하여 지속적인 서비스를 제공할 수 있는 업무연속성계획(Business Continuity Planning) 및 재해복구시스템(Disaster Recovery System)에 대하여 살펴보고, 국내 금융기관의 재해복구 현황과 구축사례를 비교 분석하여 시사점을 도출해서 업무연속성계획을 기반으로 한 효과적인 재해복구시스템 구축을 위한 개선 방안 제시하고자 한다.

• Annual Conference of KIPS
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• 2008.11a
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• pp.253-256
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• 2008

데이터베이스 시스템의 사용은 다양한 분야에서 필수적으로 사용되고 있다. 정보의 양이 증가함에 따라서 축적된 정보들의 연관성을 찾아내어 새로운 정보를 발굴하는 데이터 마이닝 기법이 지속적으로 연구 개발되고 있으며 데이터 마이닝 기법으로 얻게 된 새로운 정보들은 새로운 가치 창출을 위해 여러 분야에 적용되고 있다. 그 중에서도 의료 서비스 분야에서의 데이터베이스 시스템은 고령화 시대에 건강의 중요성이 강조됨에 따라 보다 적극적으로 활용되어지고 있다. 하지만 지금까지의 의료분야에서의 데이터베이스 시스템 활용은 개인의 의료정보를 데이터베이스 시스템에 저장하고 그것을 바탕으로 개인의 건강에 대한 검진이나 치료 등의 서비스를 제공하는데 국한되어왔다. 개인 맞춤 의료 서비스에도 불구하고 유전이나 지역특화적인 질병, 질환에 의한 때늦은 발견과 치료는 여전히 많은 이들을 고통 받게 하고 있다. 이에 본 논문에서는 각 의료기관에 등록된 환자의 각 질병의 발병 패턴과 치료 정보 등을 토대로 유전적요인과 환경적 특성을 고려한 집단으로 분류하고 환자가 속한 집단구성원에게 검진정보를 제공할 수 있는 의료검진정보 시스템을 제안한다.