연안 페리선박에 고박된 트레일러의 가속도 분석을 통한 사고 위험성의 추정 알고리즘 개발

이상원 (사)한국연안방재학회 2024 한국연안방재학회지 Vol.11 No.1

Coastal ferry has the main purpose to transport cargo such as vehicles and trailers, as well as to transport passengers. For safe cargo transportation, the cargo securing safety of coastal ferry must be ensured to prevent the maritime accident. However, the standards for the cargo securing safety are not properly presented as the rules for coastal ferry in accordance with actual operations. Therefore, coastal ferry is exposed to the risk of accidents due to not sufficient standards for the cargo securing safety. In this study, the accident of coastal ferry that occurred in Korea and Japan are analyzed from the perspective of cargo securing safety. First, the wave conditions at the time of the accident were reproduced using a wave simulation model. The reproduced wave spectrum was applied to the ship motion models to estimate rolling and pitching of the coastal ferry. Finally, the acceleration of the trailer loaded on the ferry was calculated based on the ship motions. The simulated results were compared and evaluated with the standard value of IMO's Cargo Securing Manual. As a result, the exact accident time was predicted, and the wave height and ship motions were additionally presented as evaluation criteria for cargo securing safety. The results of this study are expected to improve the safety standards of coastal ferry and could reduce the maritime accident cause by the insufficient cargo securing.

동해 연안의 추적자 확산 정보를 제공하는 장거리형 고주파 해양 레이더 시스템

손영태,박재형,김정현,남성현 (사)한국연안방재학회 2019 한국연안방재학회지 Vol.6 No.2

We have conducted a virtual surface layer dispersion experiment using the long-range High Frequency radar (HFR) measurements off the east coast of Korea, and investigated the spreading characteristics of the surface waters in the vicinity of two cities, YoungDuk and UlJin for three days of experiments utilizing with random flight model (Markovian stochastic model). The diffusion coefficient was estimated as (Kx, Ky) = (192, 251) m2/s with zonal and meridional dispersions (  ,  ) = (0.0013, 0.017) m/s and turbulence time scales (Tu, Tv) = (4, 4) hours derived from exponential fitting of lagged autocorrelation of difference between the HFR-derived and surface drifter-derived currents. During the experiment period, the centroid of the spatial particle distribution moved northward 80 km from the initial position following the East Korea Warm Current (EKWC) and its area became more than 500 times than the initial area. The trajectory and distribution of the surface particles are dependent on the EKWC and diffusion coefficient. Long-term and real-time continuous monitoring system of HFR needs to be combined into national system to improve search and rescue (SAR), and prevent coastal disasters (e.g., oil spill, marine litter) for risk management.

유지관리 모니터링을 통한 국가어항 방재시스템의 유지관리수준에 관한 연구

조영진,김영서 (사)한국연안방재학회 2019 한국연안방재학회지 Vol.6 No.2

The breakwater of the national fishery port is currently under going rapid aging and the possibility of destruction due to climate change is increasing and maintenance costs are expected to rise sharply. Therefore, it is necessary to reduce the cost of LCC by securing the safety of the national fishery port breakwater and long life. Based on this recognition, this study defines the maintenance level of the national fishery port breakwater and suggests appropriate maintenance level for rational decision making of maintenance. The appropriate maintenance level of national fishery port breakwater is as follows: 1. The maintenance according to service life of facilities is current maintenance level, 2. The maintenance according to breakwater damage rate is Current maintenance level or preventive maintenance level, 3. The maintenance according to change in design wave is preventive maintenance level.

남해안 연안 조석정보 데이터베이스 구축 및 조석예측

김창겸,전인식,오병철,이호진,최지은,문은혜 (사)한국연안방재학회 2022 한국연안방재학회지 Vol.9 No.4

The construction of the tidal information database study was conducted through numerical simulations for the southern coast of Korea. Because Korea has a complex coastline, the grid size of the numerical model was set to 0.1min(approx. 200m) to improve the accuracy of tidal prediction. The NAO.99jb, one of the ocean tide models, was employed in the study to increase the accuracy of the database. The numerical model applied to the database construction was calibrated and validated using observation data from the Korea hydrographic and oceanographic agency. To construct a high-resolution tidal information database, we conducted harmonic analysis for each computational grid point using numerical simulation results. In order to evaluate the tide and tidal current prediction performance of the tidal information database, numerical simulation results were used and compared. The results show that the predictive performance of the harmonic constant database is sufficient, so it can be used where rapid tidal prediction is required.

수심 및 AIS 데이터 기반의 공간분석을 활용한 연안 수역 내 고밀도 등심선 생성에 관한 연구

김윤지,이정석,공길영,조익순 (사)한국연안방재학회 2022 한국연안방재학회지 Vol.9 No.2

ECDIS provides safety function related to depth and contour lines to prevent grounding of ship. However, since the most ENCs contain depth contours at intervals of 2, 5, 10, 20, 30m, it is difficult to provide precise information to users and have limitations as a function of anti-grounding. Recently, the IHO recognized this problem and recommended the production of HD(High Density) ENC that provides depth contours at 1m intervals in confined water. In this study, spatial analysis was performed based on AIS and marine accident data to determine the depth contour ranges and areas required for HD ENC production. The study area was selected near Incheon and Pyeongtaek port on the west coast of Korea and depth contour lines with 1m intervals were created based on the TIN(Triangulated Irregular Network) interpolation algorithm and DEM(Digital Elevation Model) using the water depth data of the digital nautical chart. After that, the distribution of ship’s draft was analyzed based on the AIS data, and the spatial autocorrelation analysis using marine accident data indicates the need to provide dense contour lines in the fairway of Incheon and Pyeongtaek. It is expected to HD ENC that reflects the environment of the area and the characteristics of ships can help safe navigation of ships and prevent marine accidents.

연안도시 침수예측을 위한 SIND 모형의 활용방안

김동현,유형주,방영준,이승오 (사)한국연안방재학회 2022 한국연안방재학회지 Vol.9 No.4

Flooding damage is increasing due to abnormal climates. In particular, in the case of coastal cities, it is necessary to simultaneously consider inundation caused by marine disasters such as storm surge and tsunami as well as inundation due to urbanization. In order to respond to disasters in coastal cities, flood prediction must be preceded. In Korea, the intensity of disasters has been classified by frequency, and flood hazard maps have been produced accordingly. The map is generally derived through numerical simulation, which is based on a scenario, so there is a lot of uncertainty, and it is difficult to predict a disaster for which a scenario has not been established. Because the target range of the coast is wide, the calculation speed of numerical simulation is slow, and a considerable amount of time is required for inundation prediction. It is practically difficult to predict a disaster such as torrential rain in a short period of time. Therefore, in this paper, by using the SIND model, a scientific interpolation model proposed by Kim et al. (2018), the ability to predict the inundation of coastal cities was reviewed and the method of using the model was presented. The SIND model is a short-term prediction model of urban inundation for a desired scenario within the range by using a pre-established inundation forecast map, and can be used for short-term inundation prediction such as torrential rain. To examine the applicability, the accuracy of the flood hazard map derived from the SIND model for coastal cities was analyzed. As a result, it was confirmed that the shape similarity suggested by Kim et al. (2019) was about 0.7 or higher, and it was judged to be appropriate in terms of shape similarity. If the shape similarity technique used for model validation is improved to suit the urban flooding characteristics, the use of the SIND model is expected to increase.

국내 연안역에서의 해수면의 시간적⋅공간적 변화 분석

양수현,안태용,황규남 (사)한국연안방재학회 2022 한국연안방재학회지 Vol.9 No.3

In this study, the temporal and spatial changes of sea level in Korean coastal zone were analyzed. First, the error value of 1 hour tide data provided by the Korea Hydrographic and Oceanographic Agency was excluded through preprocessing, the analysis of sea level change was performed by considering long period components through low-pass filtering. Using low-pass filtering data, the monthly mean sea level was calculated and the temporal changes of sea level were verified by data fitting using linear fit and multidimensional smoothing spline. The results of linear fit show that the tide tends to rise at most stations. And the results of multidimensional smoothing spline fit show that the increase and decrease of sea level is repeated every year. Although the amounts of change vary every year, sea levels have been repeated seasonally, with sea levels rising in summer and falling in winter. Also, Hovmöller diagram was prepared for the change of sea level in each east, west, and south coast, and the temporal and spatial changes of sea level were analyzed. Compared to the past, recent sea level changes increased in all points. Especially, in the west coast, the sea level increased more in the south (Mokpo) area than in the north (Yeongjong Bridge), and the south (Mokpo) area of the west coast could be a vulnerable area due to the rise in sea level.

연안 파랑 수치모델링을 위한 심해파 ERA5 자료의 적용 가능성 연구

손동휘,유제선,신현화 (사)한국연안방재학회 2018 한국연안방재학회지 Vol.5 No.2

The purpose of this study is to investigate the applicability of ERA5 reanalysis data to force nearshore wave model(SWAN) in Korea. A nearshore wave model was set up to simulate wave transformations in December 2016, in Ilsan beach located in Ilsan-dong, Ulsan Metropolitan City. The numerical results by ERA5 inputs were compared with the results by ERA-Interim inputs. The ERA5-based simulation results show better agreement with field observations than the ERA-Interim ones do. In addition, the wave model results have been improved by applying whitecapping empirical formulas of Rogers et al.(2012) among physical parameters.

태풍 기인 연안침식 예측의 불확실성 분석: 사례연구-일산해변

손동휘,유제선,신현화 (사)한국연안방재학회 2019 한국연안방재학회지 Vol.6 No.3

In coastal morphological modelling, there are a number of input factors: wave height, water depth, sand particle size, bed friction coefficients, coastal structures and so forth. Measurements or estimates of these input data may include uncertainties due to errors by the measurement or hind-casting methods. Therefore, it is necessary to consider the uncertainty of each input data and the range of the uncertainty during the evaluation of numerical results. In this study, three uncertainty factors are considered with regard to the prediction of coastal erosion in Ilsan beach located in Ilsan-dong, Ulsan metropolitan city. Those are wave diffraction effect of XBeach model, wave input scenario and the specification of the coastal structure. For this purpose, the values of mean wave direction, significant wave height and the height of the submerged breakwater were adjusted respectively and the followed numerical results of morphological changes are analyzed. There were erosion dominant patterns as the wave direction is perpendicular to Ilsan beach, the higher significant wave height, and the lower height of the submerged breakwater. Furthermore, the rate of uncertainty impacts among mean wave direction, significant wave height and the height of the submerged breakwater are compared. In the study area, the uncertainty influence by the wave input scenario was the largest, followed by the height of the submerged breakwater and the mean wave direction.

동해 냉수대 발생 예측시스템 개발

이준수,송지영,박명희,권미옥,한인성,정래홍 (사)한국연안방재학회 2022 한국연안방재학회지 Vol.9 No.3

In this study, a forecast system for the occurrence of cold waters in the eastern coast of Korea was developed by combining the ROMS ocean model and the WRF regional atmospheric model. The 1-day hindcast and 3.5-day forecasts from April 1 to August 31, 2021, successfully reproduced and forecasted the temporal and spatial changes of coastal cold waters. Three case studies with different surface boundary conditions in the ROMS model confirmed that the wind is a primary driver for the occurrence of cold waters in the region. The performance of the ROMS was improved by high-resolution WRF outputs, and through error correction using the water temperature data from the real-time stations, the average RMSE of 9 stations for Forecast Day-3 was 0.73℃, indicating a prossibility of high-precision forecast.