Surface water temperature of a bay (from the south to the north) increases in spring and summer, but decreases in autumn and winter. Due to shallow water depth, freshwater outflow, and weak current, the water temperature in the central to northern part of the bay is greatly affected by the land coast and air temperature, with large fluctuations. Water temperature variations are large in the north-east coast of the bay, but small in the south-west coast. The difference between water temperature and air temperature is greater in winter and in the south-central part of the bay than that in the north to the eastern coast of the bay where sea dykes are located. As the bay goes from south to north, the range of water temperature fluctuation and the phase show increases. When fresh water is released from the sea dike, the surrounding water temperature decreases and then rises, or rises and then falls. The first mode of empirical orthogonal function (EOF) represents seasonal variation of water temperature. The second mode represents the variability of water temperature gradient in east-west and north-south directions of the bay. In the first mode, the maximum and the minimum are shown in autumn and summer, respectively, consistent with seasonal distribution of surface water temperature variance. In the second mode, phases of the coast of Seosan~Boryeong and the east coast of Anmyeon Island are opposite to each other, bordering the center of the deep bay. Periodic fluctuation of the first mode time coefficient dominates in the one-day and half-day cycle. Its daily fluctuation pattern is similar to air temperature variation. Sea conditions and topographical characteristics excluding air temperature are factors contributing to the variation of the second mode time coefficient.
The creation of marine protected areas is an important aspect of marine ecosystem sustainability. However, South Korea has not achieved its Aichi Biodiversity Target to designate 10% of its sea as marine protected by 2020. Local residents have strong opposition to the designation of protected areas in South Korea; there has been little trust in the government since the 1970s, when residents felt that their property rights were being ignored in favor of creating national parks. Here, we present a case where creation of a marine protected area was led by residents of TongYeong City. The success of a participation income project to remove marine debris in the city seems to be an important factor that led to the designation of the marine protected area. The case of TongYeong City is compared with that of nearby Geoje City, where an ecologically important stream has not been designated as a wetland protection area, although a similar participation income project enrolled the city's residents. The comparison provides a tentative assessment of the conditions needed to increase trust among residents. The results suggest that, if the projects are well-designed and well-managed, participation income projects to remove marine debris can be effective in building trust among stakeholders in potential marine protected areas.
Establishing a ship's passage plan is an essential step before it starts to sail. The research related to the automatic generation of ship passage plans is attracting attention because of the development of maritime autonomous surface ships. In coastal water navigation, the land, islands, and navigation rules need to be considered. From the path planning algorithm's perspective, a ship's passage planning is a global path-planning problem. Because conventional global path-planning methods such as Dijkstra and A* are time-consuming owing to the processes such as environmental modeling, it is difficult to modify a ship's passage plan during a voyage. Therefore, the D* algorithm was used to address these problems. The starting point was near Busan New Port, and the destination was Ulsan Port. The navigable area was designated based on a combination of the ship trajectory data and grid in the target area. The initial path plan generated using the D* algorithm was analyzed with 33 waypoints and a total distance of 113.946 km. The final path plan was simplified using the Douglas–Peucker algorithm. It was analyzed with a total distance of 110.156 km and 10 waypoints. This is approximately 3.05% less than the total distance of the initial passage plan of the ship. This study demonstrated the feasibility of automatically generating a path plan in coastal navigation for maritime autonomous surface ships using the D* algorithm. Using the shortest distance–based path planning algorithm, the ship's fuel consumption and sailing time can be minimized.
The purpose of this study is to evaluate the feasibility of the new marine leisure ships. In order to achieve the research purpose, the cost and income were calculated based on the operating of other marine leisure ships, and the feasibility of the project was empirically analyzed. This study established a research model that applies the values derived by empirically analyzing ships with similar specifications, to the new marine leisure ships. We then calculated the cost-benefit analysis, net present value, and internal return, and evaluated the feasibility of the project based on this. As a result of the business feasibility analysis of investing in marine leisure ship, it was found that economic feasibility exists with a B/C of 1.042 and 1.049 for new and secondhand ships, respectively; however, considering the stability of the ship and the publicity and continuity of the business operation, it is recommended to invest in new ships compared to secondhand ships. The total benefit over the 10-year operating period using a social discount rate of 4.5% was evaluated to be about KRW 292.0 billion, which is higher than the total cost of KRW 256.6 billion. In conclusion, the profitability analysis showed that the B/C was 1.042, the NPV was KRW 193 billion, and the IRR was 2.1%, which indicates that profitability is weakly secured.