• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.107-116
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• 2022

Local management trade ports are small-sized trade ports, which require active operation to strengthen the local cities' economic power and enhance the local industries' added value. In addition, local management trade ports should berth ships larger than the existing ships to increase efficiency and keep up with the international trend where ships are becoming larger. Furthermore, they should also prepare operating standards. This study selected Okgye Port among local management trade ports. We performed a mooring safety simulation evaluation according to the scenario where a 50,000 DWT vessel is moored at the current 20,000 DWT class pier. The emergency departure criteria were 27kts at 3.2s of wave period and 22kts at 5.0s of wave period at the existing pier. Results showed that mooring limit condition increased by about 50% to 41kts at 3.2s of wave period and 36kts at 5.0s of wave period. This study can be used for strengthening mooring facilities and setting operational standards for safe port operation when large ships are berthing.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.5
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• pp.144-155
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• 2022

The Korea Coast Guard evaluates the risk of major coastal activity places to prevent coastal accidents, and patrols and manages them based on that, but it is not responding properly to the continuously increasing number of coastal accidents. The reason for this is that, despite the gradual expansion of coastal activity places, there is a lack of manpower to manage and supervise them, resulting in blind spots in coastal accident safety management. Therefore, in order to solve this problem, it is necessary to prepare more efficient and effective measures that check and supplement the current coastal safety management system. Coastal accidents show different characteristics of accident causes and places due to differences in the activity characteristics of users according to time. As a result of analyzing coastal accident data (2017~2021), the frequency of daytime accidents is high in the case of sea rock, beach, and offshore, where family leisure activities are frequent. In the case of wharf, tidal flat and bridge, where accidents due to drinking, disorientation, and suicide mainly occur, the frequency of accidents at night is high. In addition, there were more accidents on weekends when the number of users increased compared to weekdays. This trend indicates that the user's temporal activity characteristics must be reflected in the risk assessment of coastal activity places. Therefore, in this study, based on the case of coastal accidents, the characteristics of accidents at coastal activity places according to time were identified, and the criteria were presented for risk evaluation by grading them. It is expected that it will be possible to lay the foundation for reducing coastal accidents by efficiently managing and supervising coastal activity places over time using the presented evaluation criteria.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.363-368
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• 2021

Ship engine rooms have improved automation systems owing to the advancement of technology. However, there are many variables at sea, such as wind, waves, vibration, and equipment aging, which cause loosening, cutting, and leakage, which are not measured by automated systems. There are cases in which only one engineer is available for patrolling. This entails many risk factors in the engine room, where rotating equipment is operating at high temperature and high pressure. When the engineer patrols, he uses his five senses, with particular high dependence on vision. We hereby present a preliminary study to implement an engine-room patrol robot that detects and informs the machine room while a robot patrols the engine room. Images of ship engine-room equipment were classified using a convolutional neural network (CNN). After constructing the image dataset of the ship engine room, the network was trained with a pre-trained CNN model. Classification performance of the trained model showed high reproducibility. Images were visualized with a class activation map. Although it cannot be generalized because the amount of data was limited, it is thought that if the data of each ship were learned through transfer learning, a model suitable for the characteristics of each ship could be constructed with little time and cost expenditure.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.1013-1022
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• 2022

Recently, with the worldwide development of the fourth industry, the development of technologies for smart and eco-friendly ships is accelerating. With the emergence of autonomous vessels with complete unmanned or minimum personnel on board and eco-friendly fuel (methane, ammonia, electricity, etc.), the role of existing seafarers on board is expected to change significantly. To improve the competitiveness of seafarers in the future, predicting future seafarer occupation groups, improving the educational curriculum, and creating an educational system are necessary. In this study, eight occupational groups that seafarers may have in the future were derived through a review of earlier studies and brainstorming of maritime university students, incumbent seafarers and expert groups. A survey was conducted on the eight occupational groups using the Likert scale, and based on the results, a leading occupational group related to future seafarer was derived. The most likely occupational groups with high scores were remote control centre operators and cargo remote manager. In addition, essential educational elements to be educated first for these occupational groups were derived and presented.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.1054-1062
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• 2022

The population of Korea's solar salt-producing regions is rapidly aging, resulting in a decrease in the number of productive workers. In solar salt production, salt collection is the most labor-intensive operation because existing salt collection vehicles require human operators. Therefore, we intend to develop an unmanned solar salt collection vehicle to reduce manpower requirements. The unmanned solar salt collection vehicle is designed to identify the salt collection status and location in the salt plate via color detection, the color detection performance is a crucial consideration. Therefore, an image processing algorithm was developed to improve color detection performance. The algorithm generates an around-view image by using resizing, rotation, and perspective transformation of the input image, set the RoI to transform only the corresponding area to the HSV color model, and detects the color area through an AND operation. The detected color area was expanded and noise removed using morphological operations, and the area of the detection region was calculated using contour and image moment. The calculated area is compared with the set area to determine the location case of the collection vehicle within the salt plate. The performance was evaluated by comparing the calculated area of the final detected color to which the algorithm was applied and the area of the detected color in each step of the algorithm. It was confirmed that the color detection performance is improved by at least 25-99% for salt detection, at least 44-68% for red color, and an average of 7% for blue and an average of 15% for green. The proposed approach is well-suited to the operation of unmanned solar salt collection vehicles.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.967-976
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• 2021

Over the last ten years, the number of entanglement marine accidents has increased more than other accident types. This study analyzed the annual statistical report of marine accidents from the Korea Maritime Safety Tribunal and Korea Coast Guard. Despite some discrepancies between data of the two organizations, it was found that marine accidents involving fishing vessels were more prevalent than those involving non-fishing vessels. In addition, the main floating materials that caused wounded entanglement accidents were fishing nets, fishing gear, and ropes, and the proportion of them was high. Foreign and domestic policies on marine plastics recognize most marine plastics as marine environmental hazards and focus on marine litter recovery and the prevention of marine pollution. The representative Acts related to the marine environment and marine litter, the Marine Environment Management Act and the Marine Waste and Sediments Management Act, recognize marine litter as a type of marine waste, and deal with the types and definition of this waste. However, clearly defining marine waste is difficult. Therefore, this study tried to examine the relevant legal system of marine litter on ship operation and suggested improvement measures. Moreover, the definition of marine litter for the safe navigation and operation of ships was clearly proposed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1004-1010
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• 2021

Ship-floating object accidents can lead not only to a delay in ship's operations, but also to large scale casualties. Hence, preventive measures are required to avoid them. This study analyzed the spatiotemporal aspects of such collisions based on the data on ship-floating object accidents in sea areas in the last five years, including the collisions in South Korea's territorial seas and exclusive economic zones. We also provide basic data for related research fields. To understand the distribution of the relative density of accidents involving floating objects, the sea area under analysis was visualized as a grid and a two-dimensional histogram was generated. A multinomial logistic regression model was used to analyze the effect of variables such as time of day and season on the collisions. The spatial analysis revealed that the collision density was highest for the areas extending from Geoje Island to Tongyeong, including Jinhae Bay, and that it was high near Jeongok Port in the West Sea and the northern part of Jeju Island. The temporal analysis revealed that the collisions occurred most frequently during the day (71.4%) and in autumn. Furthermore, the likelihood of collision with floating objects was much higher for professional fishing vessels, leisure vessels, and recreational fishing vessels than for cargo vessels during the day and in autumn. The results of this analysis can be used as primary data for the arrangement of Coast Guard vessels, rigid enforcement of regulations, removal of floating objects, and preparation of countermeasures involving preliminary removal of floating objects to prevent accidents by time and season.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.800-808
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• 2022

The International Maritime Organization adopted the interim standards for ship maneuverability in November 1993 for preventing collision of ships at sea and for protecting the marine environment, and based on the accumulated data, in December 2002, the established standards for ship maneuverability were adopted. However, the standards adopted are those at full load, even keel, and at least 90 % of the ship speed at 85 % of the ship's maximum power. Moreover, these standards have limitations in providing information on maneuverability under actual navigational conditions. Therefore, in this study, frequency analysis AHP analysis techniques were studied by consulting navigational officers, captains, and experts, who have significant knowledge on ship maneuverability, utilization of the current standards, and the information necessary for the operation of the actual ship. The results of this study confirmed that the necessary information on maneuverability for the navigational officer operating the vessel is information about the turning circle at a small angle of 5°-10° and z-test information at maneuvering speed, not sea speed. Additionally, in relation to speed control, additional information on deceleration inertia and acceleration inertia is needed than the information on the stopping ability at sea speed and full loaded condition. The derived results are considered to be useful as basic data for preparing guidelines for ship maneuverability necessary for navigational of icers who operate ships.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.5
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• pp.462-469
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• 2023

In this study, we propose a method for evaluating the risk of collision between ships to support determination on the risk of collision in a situation in which ships encounter each other and to prevent collision accidents. Because several uncertainties are involved in the navigation of a ship, must be considered when evaluating the risk of collision. We apply the Dempster-Shafer theory to manage this uncertainty and evaluate the collision risk of each target vessel in real time. The distance at the closest point approach (DCPA), time to the closest point approach (TCPA), distance from another vessel, relative bearing, and velocity ratio are used as evaluation factors for ship collision risk. The basic probability assignments (BPAs) calculated by membership functions for each evaluation factor are fused through the combination rule of the Dempster-Shafer theory. As a result of the experiment using automatic identification system (AIS) data collected in situations where ships actually encounter each other, the suitability of evaluation was verified. By evaluating the risk of collision in real time in encounter situations between ships, collision accidents caused by human errora can be prevented. This is expected to be used for vessel traffic service systems and collision avoidance systems for autonomous ships.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.1
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• pp.76-85
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• 2023

Demand for hydrogen as a renewable energy resource is increasing. However, unlike conventional fossil fuels, hydrogen requires a dedicated refueling station for fuel supply. A risk assessment of hydrogen refueling stations must be undertaken to secure the infrastructure. Therefore, in this study, a risk assessment for hydrogen refueling stations was conducted through both qualitative and quantitative risk assessments. For the qualitative evaluation, the hydrogen dispenser module was evaluated as two nodes using the hazard and operability (HAZOP) analysis. The risk due to filter clogging and high-pressure accidents was evaluated to be high according to the criticality estimation matrix. For the quantitative risk assessment, the Hydrogen Korea Risk Assessment Module (Hy-KoRAM) was used to indicate the shape of the fire and the range of damage impact, and to evaluate the individual and social risks. The individual risk level was determined of to be as low as reasonably practicable (ALARP). Additional safety measures proposed include placing the hydrogen refueling station about 100m away from public facilities. The social risk level was derived as 1E-04/year, with a frequency of approximately 10 deaths, falling within the ALARP range. As a result of the qualitative and quantitative risk assessments, additional safety measures for the process and a safety improvement plan are proposed through the establishment of a restricted area near the hydrogen refueling station.