• Journal of Ocean Engineering and Technology
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• v.37 no.3
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• pp.122-128
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• 2023

Autonomous berthing is a crucial technology for autonomous ships, requiring optimal trajectory planning to prevent collisions and minimize time and control efforts. This paper presents a two-phase, two-point boundary value problem (TPBVP) strategy for creating an optimal berthing trajectory for a twin-propeller, twin-rudder ship with autonomous berthing capabilities. The process is divided into two phases: the approach and the terminal. Tunnel thruster use is limited during the approach but fully employed during the terminal phase. This strategy permits concurrent optimization of the total trajectory duration, individual phase trajectories, and phase transition time. The efficacy of the proposed method is validated through two simulations. The first explores a scenario with phase transition, and the second generates a trajectory relying solely on the approach phase. The results affirm our algorithm's effectiveness in deciding transition necessity, identifying optimal transition timing, and optimizing the trajectory accordingly. The proposed two-phase TPBVP approach holds significant implications for advancements in autonomous ship navigation, enhancing safety and efficiency in berthing operations.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.910-914
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• 2023

With the technological innovation owing to the 4th industrial revolution, the maritime transportation is rapidly being developed with autonomous ships and systems. Particularly, autonomous ships will partially replace the manned ships and navigation among them remotely upon the degree of autonomy suggested by IMO. Accordingly, the remote operator and related research have increased as well. However, the data on the minimum required manpower for remote operators are lacking such as considering engage required situations and their co-occurrence probability. Therefore, this study proposes a simulation model that calculates the number of remote engage required situations by defining restricted water area and remote engage required situation as close-quarter situations based on accumulated trajectory data of actual ships. The findings are expected to be used as background materials to establish the appropriate manpower distribution of remote operators in remote operation centers.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.150-152
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• 2018

국제해사기구의 MSC 98차 회의에서 새로운 도출 의제로 MASS(Maritime Autonomous Surface Ships)가 포함됨에 따라 선박 자동화와 무인화는 해상분야의 국제적인 이슈로 떠올랐다. 유럽의 선급과 연구소 및 제조사 등은 선박자동화의 수준을 다양하게 정의하고 있으나 기술요소와 시스템을 기반으로 하고 있어 선원의 역할과 교육분야에 대한 고려는 반영되어 있지 않다. 본 연구의 목적은 자동화 수준에 따라 항해사 또는 육상관리자에게 요구되는 해기능력을 식별하여 각 면허에 대한 적용안과 교육 및 양성에 필요한 기초연구 자료를 제시하고자 한다. 선박 자동화 수준에 대한 다양한 정의를 조사하고, 현재 항해사 및 선장 에게 요구되는 STCW 해기능력을 항목화 하였다. 선박의 자동화와 원격운항의 적용에 따라 제외되거나 추가적으로 요구되는 해기능력을 식별하고 자동화 수준별로 분류하였다. 제시된 해기능력과 면허의 구분에 대한 안을 기반으로 업계와 해기교육기관 전문가들의 검토를 통해 선박자동화와 인적요소에 대한 자동화 수준의 명확한 정의가 필요할 것이다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.25-25
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• 2023

빅데이터, AI, 인공지능 등 기술이 발전함에 있어서 자율운항도입에 따른 VTS 체계변화에 대한 인식이 필요한 실정이다. 이 연구에서는 자율운항선박이 상용화함에 따라 요구되는 적합성을 제고하기 위해 영향을 미치는 내외적인 환경요인들을 전문가집단의 브레인스토밍, 설문조사, 인터뷰 등 다방면으로 조사하고, 해당 요소를 기반으로 TOWS분석을 통해 강점(Strength), 약점(Weakness), 기회(Opportunities), 위협(Threats)의 각 요소를 상호 결합해 전략주제 도출 및 새로운 관제절차와 관련 기술, 자율운항 교육프로그램, 사이버 보안조치, 자율운항 관련 알고리즘 구성 요소 등 구체적 실행계획을 제시함으로써 예측되는 변화 대응에 기여하고자 한다.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.34-39
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• 2002

A Semi-Autonomous Underwater Vehicle (SAUV) capable of simple work at sea bed is under development in KRISO-KORDI. A pressure vessel of SAUV which is composed of FRP was manufactured to load electronic equipments. The objective of this paper is to verify the safety of the pressure vessel through conducting the structural analysis and test in pressure tank. Strain and stress under unit load were obtained by using ANSYS in the linear structural analysis. And local buckling analysis was performed with NASTRAN for the middle cylindrical hull. For the pressure test, strains were measured at three point. We found that the results by linear structural analysis and experiment are coincide well at the points where buckling does not occur. Maximum depth was estimated to be 250m by the local buckling analysis.

• Journal of Ocean Engineering and Technology
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• v.18 no.4 s.59
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• pp.52-58
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• 2004

A Semi-Autonomous Underwater Vehicle (SAUV), capable of simple work on the seabed, is under development in KRISO-KORDI. This SAUV pressure vessel is composed of fiberglass reinforced plastic (FRP), and is also manufactured to carry electronic equipment. The objective of this paper is to describe the safety check for the pressure vessel. This is achieved fly conducting structural analysis and testing in a pressure tank. Strain and stress test results, under unit load, are obtained fly using ANSYS in linear structural analysis. Local buckling analysis are performed with NASTRAN at the middle oj the cylindrical hull. The first test, using linear structural analysis, is unsuccessful, as buckling occurred. During the second test, linear structural analysis, combined with local buckling analysis, is conducted. There is no buckling up to 250 m when both ANSYS and NASTRAN are used.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.386-393
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• 2023

Recently, the demand for autonomous navigation technology has increased, and related research is also increasing. Autonomous ships generally follow the planned route, calculate the avoidance route according to the risk situation while sailing, and follow a calculated route. In general, an automatic steering device is used to follow the route, and among the operational automatic steering device methods, the route control mode is the most appropriate method to apply to autonomous ships. Therefore, in this study, we developed a route-tracking algorithm to apply an avoidance route using the navigation control mode of an automatic steering device. The algorithm was developed by dividing the straight and turning sections. A performance test was conducted to satisfy the performance suggested by IEC 62065, the relevant international standard, using simulator equipment that had acquired international certification to verify its performance. The results of the performance verification confirmed that the cross-track error, which represents the straight distance between the ship and the route, satisfied the performance standards suggested by IEC 62065 when the ship followed the route.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.38-46
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• 2021

In the era of the 4th Industrial Revolution, the interest in autonomous ship technology is increasing as high-tech technologies are being increasingly utilized throughout the industry. Therefore, we conducted a basic study on autonomous ships. In particular, a passenger ship model was produced and an autonomous navigation system was established by applying the ardupilot used for drones. The possibility of automatic control of the autonomous ship operations was confirmed by executing various voyage plans using the built model ship. In the performance test for maintaining the course the model ship could not follow the designated course straight and sailed up to 5.4 m away from the course while navigating in a zigzag (S-shape); however, after the parameters were modified, the deviation distance was reduced to a maximum of 1.8 m. In the turning performance test, the maximum diameter of the turning sphere was found to be approximately 9.3 m, but no significant change could be confirmed even after the parameters were modified. However, the results of our tests on slowing down the ship before arriving at the WP confirmed that the diameter of the turning sphere was reduced to a maximum of approximately 3.2 m. In order to evaluate the stopping performance, the last scheduled stopping position of all experiments was compared with the actual stopping position of the model ship and it was confirmed that the model ship stopped at a point at least 0.4 m and a maximum of 6.2 m away from the stopping position. In the future, improvement of course stability, turning performance, and stopping performance is required through modification and supplementation of various parameters. Moreover, a study on automatic berthing of the model ship through automatic control is planned.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.937-945
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• 2022

Maritime autonomous surface ships (MASS) have a high degree of autonomy and operate autonomously along a planned route. However, when necessary, the shore remote control center(SRCC) can directly intervene in ship operations. In this paper, the operation concept of the simulator system, which can be used to educate and train shore remote control officers, responsible for monitoring the operation of autonomous ships on land and remotely controlling them in case of an emergency, is reviewed. The required functions of the simulator system that enables the operation concept are also reviewed. The major parts of the SRCC simulator system are the monitoring station and control station, which simulate the functions of monitoring the operation status of multiple MASS and the functions of the remote operation of MASS in the case of emergency, respectively. Various units to simulate the operation of MASS and traf ic ships and various objects around the MASS are included in the simulator system. The instructor operation station is the central part of the simulator system that integrates and controls the unit systems. Functionally, as conditions under which SRCC is allowed to remotely intervene in the operation of MASS, the emergency situation for remote control (ESRC) has been defined. Moreover, the required functions to cope with these ESRC conditions have been included in the simulator system requirements.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.430-436
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• 2023

Study on Changes in Vessel Traffic Services Due to Introduction of Maritime Autonomous Surface ShipsThe development of technologies related to Maritime Autonomous Surface Ships (MASS) has been actively progressing since the mid-2010s, focusing on themes such as collision avoidance, route planning, digital twin, and communication technologies. On the other hand, research on land-based infrastructure connected with MASS, such as logistics systems, port facilities, and vessel traffic services, has relatively received less attention. This study analyzed impact of emergence of MASS on existing vessel traffic service operations and proposed changes in control operations to prepare for its impact. To do this, current vessel traffic service operations were analyzed and elements of MASS technology that could affect vessel traffic control were identified. A survey was conducted among vessel traffic controllers to identify items related to the control of MASS. Results analyzed using the AHP method showed that preparation for emergency response and communication methods with MASS were the most important. Based on this, we were able to derive detailed plans for basic MASS control procedures and emergency response procedures based on data communication within maritime traffic control areas. MASS control procedures proposed in this study are expected to be used as a solution to resolve issues related to traffic safety of MASS in coastal areas.