• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.45-52
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• 2018

As guidelines for exhaust gases of ship are reinforced by the International Maritime Organization, the necessity for LNG fuelled ship is emerging. The relevant research is actively progressing to develop technologies and promote commercialization. When the residual quantity of LNG fuel tank is less than 70% by consuming fuel during operation, sloshing should be considered. We applied the Type C LNG fuel tank because medium sized LNG fuelled ships are difficult to equip with re-liquefaction system. Structural integrity and thermal performance are very important, especially in LNG fuel tanks that apply to LNG fuelled ship. Through this study, we proposed evaluation procedure of thermal performance for the Type C LNG tank, and verified the validity and effectiveness of BOR(Boil-Off Rate) test Procedure by comparing and analyzing changes in temperature, pressure, BOG(Boil-Off Gas).

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.586-594
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• 2012

A future type ship power system requires both economic and eco-friendliness. That is, this should be reduced the discharge quantity of air pollutants and green-house gases as well as have high energy efficiency. Recently, gas turbines have been realized a lot of technical development in terms of efficiency and safety, and are widening the example of their adoption to a GT/ST hybrid system in a power plant as well as an aviation use. This paper reviewed the performance characteristics of a GT/ST hybrid system of several ten MW class, not large capacity, with a simulation in order to evaluate the possibility of a GT/ST hybrid system for ships. The reviewed GT/ST hybrid system has maximum 49 % efficiency, has the highest efficiency point for TIT, and has a 70~75 % and 25~30 % load ratio for a gas turbine and a steam turbine respectively.

• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.177-183
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• 2006

IMO and ITU-R have done an intensive study to develop performance standards and technical standards of maritime digital communication systems, respectively. In particular, each administration strives to develop new agenda items of adopting digital new technologies. IMO COMSAR submitted draft performance standard of LRIT to IMO MSC, so that IMO mandates carriage requirement of LRIT In addition to that, COMSAR is preparing performance standard of AIS-SART, and approved the utilization of mobile phones for SAR activities. On the other hand, a new agenda item concerning E-navigation strategy was submitted to MSC 81th meeting. These challenges toward enhanced maritime radio communication systems would make it change largely the concepts of traditional navigation We suggest future directions of maritime information communication systems, investigating the study results of IMO and ITU-R.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.1
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• pp.181-190
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• 2007

This paper presents a collision avoidance system for intelligent ship. Unlike collision avoidance system of other unmanned vehicles, the collision avoidance system for intelligent ship aims at not only deriving a reasonable and safe path to the goal but also keeping COLRECs(International Regulations for Preventing Collisions at Sea). The heuristic search based on the BK-products is adopted to achieve the general purpose of collision avoidance system; deriving a reasonable and safe path. The rule of action to avoid collision is adopted for the other necessary and sufficient condition; keeping the COLREGs. The verification of proposed collision avoidance system is performed with scenarios that represent encounter situations classified in the COLREGs, then it is compared with $A^{\ast}$ search method in view of optimality and safety. The analysis of simulation result revels that the proposed collision avoidance system is practical and effective candidate for real-time collision avoidance system of intelligent ship.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.856-866
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• 2021

The increasing international awareness regarding air pollutant reduction has resulted in increasing demand for eco-friendly ships; hence, electric ships are being actively developed by various countries. Presently, studies on electric ships are mainly focused on electric propulsion systems and electric motors. However, from the ship perspective, there are no studies on conceptual designs for coastal car ferries powered by removable power supply systems. In the present study, the main research consideration is regarding the conceptual design of a fully electrified car ferry using a battery-based removable system as the main power source. By analyzing the dimensions of more than 100 domestic coastal car ferries, the main criteria satisfying the requirements for developing a suitable vessel were derived, and a study on intact/damage stability was conducted considering the application of a removable battery truck. Further analyses of the problems concerning the conceptual design were also performed to derive solutions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.2
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• pp.111-117
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• 2009

IMO is treating various and numerous agenda with time, and the contents of agenda have been tending to achieve international standardization for details of technology, for example GBS(Goal based new ship construction standards), PSPC(Performance Standards of Protective Coating), LRIT(Long-Range Identification and Tracking of Ships), etc. This paper presents the latest agenda trend of IMO committees and analyzes the ROK's activities in response to IMO committees. In the result of analysis, ROK lacks in performance ability as a A-category council member as well as infrastructure to support the government activities in IMO continuously. Therefore, ROK should be conscious of policy approaches to international maritime tendency and needs to complete the internal/external infrastructure which leads the international maritime policy.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.200-207
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• 2017

The purpose in having a control surface on ships is to control the motion of the ship. The control surface may be composed entirely of a single movable surface or of a combination of fixed and movable portions. A control surface has one sole function to perform in meeting its purpose, and that is to develop a control force in consequence of its orientation and movement relative to the water. The forces and moments generated as a result of this rotation and angle of attack then determine the manoeuvring characteristics of the ship. In this paper, two-dimensional flow characteristics of a flapped rudder and a water-blowing control rudder were accomplished respectively by PIV method in a circulating water channel. Model test has been carried out with different angles of attack of main foil (NACA 0012) and flap's deflection angles to predict the performance of the flapped rudder and the water-blowing control rudder. The 2-frame particle tracking method has been used to obtain the velocity distribution in the flow field. $Re{\fallingdotseq}3.0{\times}10^4$ has been used during the whole experiments and measured results have been compared with each other.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.7
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• pp.933-940
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• 2017

Draught and trim conditions are highly related to the loading condition of a vessel and are important factors in predicting ship manoeuverability. This paper estimates hydrodynamic coefficients from sea trial measurements with three different trim and draught conditions. A mathematical optimization method for system identification was applied to estimate the forces and moment acting on the hull. Also, fast time simulation software based on the Rheinmetall Defense model was applied to the whole estimation process, and a 4,500 Twenty-foot Equivalent Unit (TEU) class container carrier was chosen to collect sets of measurement data. Simulation results using both optimized coefficients and newly-calculated coefficients for validation agreed well with benchmark data. The results show mathematical optimization using sea measurement data enables hydrodynamic coefficients to be estimated more simply.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.499-506
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• 2022

For autonomous ships to be commercialized and be able to navigate in coastal water, they must be able to detect maritime obstacles. One of the most common obstacles seen in coastal area are the farm buoys. In this study, a maritime object detection system was developed that detects buoys using the YOLO algorithm and visualizes the distance and bearing between buoys and the ship through geometric interpretation of camera images. After training the maritime object detection model with 1,224 pictures of buoys, the precision of the model was 89.0%, the recall was 95.0%, and the F1-score was 92.0%. Camera calibration had been conducted to calculate the distance and bearing of an object away from the camera using the obtained image coordinates and Experiment A and B were designed to verify the performance of the maritime object detection system. As a result of verifying the performance of the maritime object detection system, it can be seen that the maritime object detection system is superior to radar in its short-distance detection capability, so that it can be used as a navigational aid along with the radar.

• Journal of Navigation and Port Research
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• v.43 no.1
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• pp.23-32
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• 2019

In this paper, we proposed a multi-chain Time of Arrival (ToA) positioning method to estimate positions using all received Loran-C signals from multiple chains without constraining to a single chain. Conventionally, we have to choose only one chain among several available chains for position estimation using Loran-C. Therefore, the number of signals to be used for positioning is limited to three to five. In general, if more signals are used for positioning estimation, its performance tends to be improved in terms of accuracy and availability. To validate the proposed method for multi-chain Loran-C, we firstly carried out a static positioning test in land. By analyzing the test results, we confirmed that the proposed method works well under a multi-chain Loran-C scenario. Subsequently, another mobile positioning test was conducted on board a vessel under a practical application scenario. From this second test, we successfully demonstrated that the multi-chain ToA positioning method even in situations where the conventional single-chain Loran-C approach fails for positioning.