• Journal of Ocean Engineering and Technology
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• v.23 no.4
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• pp.58-63
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• 2009

Two kinds of welding methods are used for austenitic 304 stainless steel: laser welding and TIG welding. The difference in the corrosion characteristics of the welded zone between these two welding methods was investigated using electrochemical methods, such as corrosion potential measurements, polarization curves, cyclic voltammograms, etc. The Vickers hardnesses of all the welded zones (WM: Weld Metal, HAZ: Heat Affected Zone, BM: Base Metal) showed relatively higher values in the case of laser welding than for TIG welding. Furthermore, the corrosion current densities of all the welding zones showed lower values compared to TIG welding. In particular, the corrosion current density of the HAZ with TIG welding had the highest value of all the welding zones, which suggests that chromium depletion due to the formation of chromium carbide appears in the HAZ, which is in the range of the sensitization temperature. Thus, it can easily be corroded with a more active anode. Consequently, we found that the corrosion resistance of all of the welding zones for austenitic 304 stainless steel could apparently be improved by using Laser welding.

• Journal of Navigation and Port Research
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• v.34 no.5
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• pp.311-317
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• 2010

Mobile Harbor(MH) is a new paradigm for maritime transport system introduced in Korea, the target of which is to carry out ship-to-ship cargo operation rapidly and effectively even under a condition of sea state 3. A MH ship is moored alongside a large container vessel anchored at the defined anchorage and also equipped with gantry cranes for handling containers. The MH study concerned includes rapid container handling system, optimum design for floating structure, hybrid berthing & cargo operation system, design for cargo handling crane, etc. This paper is to deal with a conceptual design of a stabilized mooring system and mooring equipment under a condition of ship-to-ship mooring. In this connection, we suggest a positioning control winch system in order to control heave motions of the MH ship which is to add constant brakepower and stabilized function to an auto-tension winch and mooring equipment used currently in large container ships.

• Journal of Welding and Joining
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• v.34 no.5
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• pp.6-12
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• 2016

This study was performed bead welding of pure titanium by using fiber laser. Since titanium is very sensitive to oxidation and nitriding during welding, it is important to compose the shielding equipment compared with different material. Thus side and coaxial shield nozzle, rail and chamber type shielding equipment are widely used to protect effectively the weld during welding. Experiments were performed by changing nozzle angle and distance using side and coaxial shield nozzle. The bead colors of gold, brown, blue, purple and yellowish white were obtained by changing variables of shield nozzle, and then its weldability was investigated. As experiment result, sound and not brominated beads were formed when side nozzle angle and distance were respectively $45^{\circ}$ and 10 mm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.1 no.1
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• pp.13-20
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• 1997

Tens of domestic maritime accidents that happen in around 5 toned small ships cause great loss of lives every year. Ship phones in small ships, the communication equipment usable in accidents, can remove factors that cause great loss of lives and properties. Thus we studied on the ship phones on a national point of view to reduce loss that caused by maritime accidents.

• Journal of Ocean Engineering and Technology
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• v.34 no.2
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• pp.55-65
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• 2020

A review of the 2nd generation of intact stability by the International Maritime Organization is performed. The main issues with the new stability criteria are reviewed. In particular, the physical background and related mathematical formulations of the pure loss of stability and parametric roll are summarized. Based on a literature review, benchmark calculation results for 17 different types of ships are discussed, and the final results are in excellent agreement with our physical expectations. Some relatively serious design problems are found in the application of the new stability criteria to sample ships built in Korea, and possible technical solutions are proposed, which have to be improved in the coming years.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.116-117
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• 2019

자율운항선박 (MASS [Maritime Autonomous Surface Ship]) 선박은 육상 관제 센터에서 선박 기자재를 상태를 실시간 모니터링하고, 컨트롤 할 수 있는 기능을 탑재하는 걱이 필수적이다. 해상과 육상을 연결하는 통신 기술 발달 뿐 아니라, 4차 산업혁명시대에 따라 빅데이터 처리 기술과 이런 빅데이터를 딥러닝 기법을 통해 분석/예측할 수 있는 기반이 마련되고 있다. 따라서 선박 기자재를 빅데이터 기반 딥러닝 등의 기법을 활용하여 원격 진단 및 유지보수 할 수 있는

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.112-118
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• 2013

This paper reports the results of a comparative study on rudder performance between the steel rudders that have been used in coastal angling fishing boats in the 20-GT class and the newly developed FRP composite material rudders. In order to compare the rudder performances of these two types, a sea trial test was carried out to investigate the speed performance, fuel consumption, and ship's turning ability. The results showed that the sea trial performance of the FRP composite rudder was better than that of the steel rudder type in terms of the sea speed, fuel consumption rate, and turning ability.

• Proceedings of KOSOMES biannual meeting
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• 2005.11a
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• pp.59-64
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• 2005

The AIS(Automatic Identification System) is the useful equipment in order to promote the maritime safety and real time monitoring at the sea. In this study, the plan to construct the ubiquitous Aids to navigation is proposed In order to verify the construction of ubiquitous Aids to navigation, the experiment on the sea was carried out and analyzed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.169-174
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• 2005

The AIS(Automatic Identification System) is the useful equipment in order to promote the maritime safety and real time monitoring at the sea. In this study, the plan to construct the ubiquitous Aids to navigation is proposed. In order to verify the construction of ubiquitous Aids to navigation, the experiment on the sea was carried out and analyzed.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.6
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• pp.473-481
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• 2023

In this study, a simulation system was developed to verify autonomous navigation algorithm in complex maritime traffic areas. In particular, real-world maritime traffic scenario was applied by considering near real-time maritime traffic information provided by Korean e-Navigation service. For this, a navigation simulation system of Unmanned Surface Vehicle (USV) was integrated with an e-Navigation equipment, called Electronic Chart System (ECS). To verify autonomous navigation algorithm in the simulation system, initial conditions including initial position of an own ship and a set of paths for the ship to follow are assigned by an operator. Then, considering real-world maritime traffic information obtained from the service, the simulation is implemented in which the ship repeatedly travels by avoiding surrounding obstacles (e.g., approaching ships). In this paper, the developed simulation system and its application on verification of the autonomous navigation algorithm in complex maritime traffic areas are introduced.