• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.4
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• pp.305-310
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• 2016

This study identified necessary navigational support services to prevent accidents through an examination and a survey on the navigation and communication systems of non-SOLAS ships. The functional and operational requirements for the identified navigational support services were discussed accordingly. Among the navigational support services proposed are an Electronic Navigational Chart (ENC) service, a route planning service, an operation monitoring service, and collision prevention support services for ships in coastal areas. To facilitate the identified navigational support services, ship navigation system, shore supporting centre and maritime communication network were discussed as a digital infrastructure. The operational methode for the digital infrastructure were discussed in the service scenarios for ships carrying dangerous cargo, large ships over 200 meters in length and high speed passenger ships over 15 knots in speed. This study will facilitate the development of policies for the improvement of ship operation management in Korean coastal waters and will contribute to improving the navigational safety of non-SOLAS ships.

• Ocean and Polar Research
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• v.37 no.1
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• pp.73-80
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• 2015

In order to determine the appropriate volume of the a pressure compensator of deep seabed mining robots, this paper reports on an experimental test for oil volume change in an oil-filled box. At the design stage of underwater robots, it is crucial to determine the capacity of the hydraulic compensator which is replenished as much as the contracted oil volume of the robots. A pilot mining robot, MienRo was designed to work under 6,000 m in the deep sea. The hydraulic actuating oil and pressure compensating oil of MineRo may be exposed at a hydrostatic pressure environment of 600 bar. Although the oil can be assumed to be incompressible, its volume is actually changed under high pressure conditions due to air contained in the oil and oil contraction. To determine the capacity of the pressure compensator, the oil contraction rate should be verified through an experimental test using a hyperbaric chamber.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.1130-1141
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• 2015

Conventionally, a pulse radar is used for middle-sized or large-sized ships to detect other ships or obstacles located at a long distance. However, it is hardly equipped for most of the small-sized ships due to mounting and maintenance costs. Therefore, FMCW(frequency modulated continuous wave) radar is suggested as an alternative for the small-sized ships. Since it operates with low power and has good range resolution for relatively close objects, it is eligible for the small-sized ships. In previously proposed FMCW radar system, it only estimates distance and velocity of a target ship placed in the direction of main beam and is hard to detect several ships simultaneously. Thus, we suggest the method for detecting several ships at the same time by applying MUSIC(multiple signal classification) algorithm to FMCW radar signal received by a phased array antenna. In addition, by combining digital beam forming with the MUSIC algorithm, better angle resolution is achievable.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.1
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• pp.179-202
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• 2014

This study was carried out to reduce the number of marine accidents on versatile small ships and to minimize the casualties. The study looked into the compulsory education systems regarding embarkation on small ships such as the Korean Marine Officers Act, conducted a survey targeting on the education receivers to suggest problems, and drew a conclusion. Conclusions are as follows. First, it is needed to give education opportunities in the system by increasing the recipients of the Ships Officers Act, and to simplify the compulsory education by separating similar courses from the education regulated by the Korean Marine Officers Act, and by establishing integrated courses suitable to each size and facility of ships. Second, in cases where the compulsory education courses of different purpose of ships by other legislations are similar, it is necessary to expand the scope of the inter-education so that corresponding year's education is exempted. Third, by classifying the education ares, the education courses should be based on case studies and the audiovisual or field education that correlates relevant expertise should be managed within a reasonable time frame. Fourth, it is needed to enhance the education effect by converting the regular education courses to practical courses by different ships for safe navigation, and is also needed to review the system so that special courses for safe navigation can be carried out in each region on a regular basis by expanding both human and financial support of special institutions.

• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.199-207
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• 2003

In the combat environments at the sea, the naval ships should have enough structural integrity to perform the task under the enemy's attack and possible damages. Although the naval ships can be damaged from the enemy's attack, those damages should be minimized and the naval ships must maintain their combat capabilities continuously after recoveries from the damages. Therefore, it is ve교 important for modem naval ships, especially combat naval ships, to ensure the survivability. This paper reviewed the developing procedure for the technique of the naval ships structures and described method, especially box girder system considering survivability. The efficiency of box girder is examined by numerical simulation, and it is found that the establishment of box girder is a good design method to improve the survivability.

• Proceedings of KOSOMES biannual meeting
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• 2005.05a
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• pp.1-6
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• 2005

According to the development of the ships navigational equipment, a bridge system has been improved but a marine accidents by human error haven't been reduced Recently It's concerned about a suitable ergonomic arrangement and design of the ships bridge equipment to reduce an error for human factors. The bridge alarm system should be designed to recognize the alarm informations as soon as possible, to deliver it clearly. Internationally, there have been a lively discussion on the BAMS(Bridge Alarm Management System) for a ergonomic bridge design, but the practical design method have not been published. In this article I would like to review a ergonomic conceptual design for the ships bridge alarm system and propose a conceptual design of the Ergonomic Integrated Bridge Alarm Management System(EIBAMS)

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.1
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• pp.161-177
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• 2013

High-speed vessels require good resistance and seakeeping performance for safe operations in rough seas. The resistance and seakeeping performance of high-speed vessels varies significantly depending on their hull forms. In this study, three planing hulls that have almost the same displacement and principal dimension are designed and the hydrodynamic characteristics of those hulls are estimated by high-speed model tests. All model ships are deep-V type planing hulls. The bows of no.2 and no.3 model ships are designed to be advantageous for wave-piercing in rough water. No.2 and no.3 model ships have concave and straight forebody cross-sections, respectively. And length-to-beam ratios of no.2 and no.3 models are larger than that of no.1 model. In calm water tests, running attitude and resistance of model ships are measured at various speeds. And motion tests in regular waves are performed to measure the heave and pitch motion responses of the model ships. The required power of no.1 (VPS) model is smallest, but its vertical motion amplitudes in waves are the largest. No.2 (VWC) model shows the smallest motion amplitudes in waves, but needs the greatest power at high speed. The resistance and seakeeping performance of no.3 (VWS) model ship are the middle of three model ships, respectively. And in regular waves, no.1 model ship experiences 'fly over' phenomena around its resonant frequency. Vertical accelerations at specific locations such as F.P., center of gravity of model ships are measured at their resonant frequency. It is necessary to measure accelerations by accelerometers or other devices in model tests for the accurate prediction of vertical accelerations in real ships.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.10a
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• pp.62-63
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• 2009

A monitoring system of collision risk among multiple ships is newly-designed in order to reduce human error and make vessel traffic control more effective. By using AIS data as ships' navigational information, an estimation algorithm of collision risk among multiple ships is newly-designed. To consider ships' course of now and future, collision risks of multiple ships can be calculated by using fuzzy algorithm. To test the performance of new algorithm, replay simulations are carried out on actual AIS data collected from VTS center of Ulsan harbor in Korea. The AIS data include 25 ships' information for two hours. In this paper, the features of newly-designed estimation algorithm of collision risk and the results of replay simulation are discussed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.259-268
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• 2019

Even if only two ships are encountered, a collision may occur due to the mistaken judgment of the positional relationship. In other words, if an officer does not know a target ship's intention, there is always a risk of collision. In this paper, the experiments are conducted to investigate how the intention affects the action of collision avoidance in cooperative and non-cooperative situations. In non-cooperative situation, each ship chooses a course that minimizes costs based on the current situation. That is, it always performs a selfish selection. In a cooperative situation, the information is exchanged with a target ship and a course is selected based on this information. Each ship uses the Distributed Stochastic Search Algorithm so that a next-intended course can be selected by a certain probability and determines the course. In the experimental method, four virtual ships are set up to analyze the action of collision avoidance. Then, using the actual AIS data of eight ships in the strait of Dover, I compared and analyzed the action of collision avoidance in cooperative and non-cooperative situations. As a result of the experiment, the ships showed smooth trajectories in the cooperative situation, but the ship in the non-cooperative situation made frequent big changes to avoid a collision. In the case of the experiment using four ships, there was no collision in the cooperative situation regardless of the size of the safety domain, but a collision occurred between the ships when the size of the safety domain increased in cases of non-cooperation. In the case of experiments using eight ships, it was found that there are optimal parameters for collision avoidance. Also, it was possible to grasp the variation of the sailing distance and the costs according to the combination of the parameters, and it was confirmed that the setting of the parameters can have a great influence on collision avoidance among ships.

• Journal of Ocean Engineering and Technology
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• v.35 no.1
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• pp.1-12
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• 2021

As increasing the international community's awareness of greenhouse gas reduction, the demand for eco-friendly ship fuel has accelerated recently. The fundamental aim of this study is to develop a new type of fully electrified ferry for passengers and cars considering Korean domestic coastal environmental conditions. Several technical difficulties are encountered in applying a fully electric propulsion system based on removable battery systems into a ship due to limitations imposed by the batteries' size and capacity. This paper reviews and analyzes marine environment regulations strengthened recently, technology trends related to fully electric propulsion vessels in each country, and Korean domestic coastal environments. We propose a new fully electrified car ferry design with a displacement of 400 t applied in Korea. It is powered by removable battery systems pre-charged in a safe inland charging station. The mobile battery system is developed to enable roll-on and roll-off using wheels. The characteristics of the ship motion are analyzed based on the weight and location of the battery systems. We expect our battery systems to be applicable to larger ships in the future.