• Journal of Navigation and Port Research
• /
• v.31 no.6
• /
• pp.479-484
• /
• 2007

For calculation of wave field for design of coastal and port structures, generally the wind fields from inland observation record or the predicted waves from deep water wave transformation model are being used. However, for the first case, as we should revise the wave data adopting correcting parameters depending on the distance from the coast and location, it is difficult to extract water waves from wind field. Furthermore, for the second case, because of the calculation which executed under very large grid sizes in the wide domain, the simulation(wave transformation) implied uncertainty in the near shore area and shallow region. So it's difficult to obtain exact data from the simulation. Thus, in this study the calculation of wave field on shallow water is accomplished using the observed data of typhoon 'Maemi' in the Korea Eastern South sea. Moreover, for the accuracy of the calculated wave field, we compared and studied the observed data of wave height and direction on the vicinity of the Ulsan waters. It is proved that the results of this study is more accurate than the existing method with showing ${\pm}1.3%$ difference between observed and calculated wave height distribution in Ulsan waters

• Journal of Digital Contents Society
• /
• v.19 no.9
• /
• pp.1739-1749
• /
• 2018

We propose a marine observation system using existing light buoys to observe various marine information of marine locations. Our proposed ocean observation system is composed of the existing standard light buoy type and can be easily connected to the light buoy. The proposed marine observation system measures the mean wave height, maximum wave height, mean wave height and water temperature measured in the ocean. Besides, it can measure the air pressure, temperature, wind speed and wind speed in real time. In order to measure important peaks in marine observations, 2200 peak data are collected for 10 minutes, and the collected data are subjected to spectral analysis to extract significant wave and wave period data. The developed system removes the noise by using the filter because the marine observation system attaches to the light buoy. We compare and analyze the measurement data of the existing proven floating marine observation system and the standard equivalent system developed. Also, it is proved that the data of the standard type backbone ocean observation system developed through the comparative experiment is similar to that of the existing ocean observation system.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.24 no.3
• /
• pp.179-188
• /
• 2012

Performance analyses of vertical breakwaters were conducted for fictitiously designed breakwaters for various water depths to analyze the influence of climate change on the structures. The performance-based design method considering sea level rise and wave height increase due to climate change was used for the performance analysis. One of the problems of the performance-based design method is the large calculation time of wave transformation. To overcome this problem, the SWAN model combined with artificial neural network was used. The significant wave height and principal wave direction at the breakwater site are quickly calculated by using a trained neural network with inputs of deepwater significant wave height and principal wave direction, and tidal level. In general, structural stability becomes low due to climate change impacts, but the trend of stability is different depending on water depth. Outside surf zone, the influence of wave height increase becomes more significant, while that of sea level rise becomes negligible, as water depth increases. Inside surf zone, the influence of both wave height increase and sea level rise diminishes as water depth decreases, but the influence of wave height increase is greater than that of sea level rise. Reinforcement and maintenance policies for vertical breakwaters should be established with consideration of these results.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.36 no.1
• /
• pp.33-44
• /
• 2000

Ships in a seaway will encounter dangerous situation, such as slamming, stranding, and capsizing. The number of capsizing is small, but the loss due to them is very large from the viewpoint of human life, property, and the environmental pollution. The number of capsizing of fishing vessels is about 62% of total number of capsizing, and the half of them is originated from the operational mistake in a seaway. So the dynamics and the capsizing phenomena are to be studied, and the guide for the safe operation of a fishing vessel in a seaway are to be specified. The hydrodynamic forces consist of radiation forces (which are due to the motion of a ship), Froude-Krylov forces (which is due to the incoming waves), and diffraction forces (which is due to the wave and ship interaction). These forces are calculated by well-known strip method. Using the calculated forces, the motion of a ship in a regular sea is obtained. In the real seaway, the waves are very irregular, therefore the statistical analysis is very helpful. In this paper, using the results of the motion in a regular seaway and the wave spectrum, the motion in a irregular seaway are obtained and analyzed.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.26 no.2
• /
• pp.65-71
• /
• 2014

In recent years, strong typhoons have passed South Korea almost every year and severe damages were incurred directly and indirectly. However, instances where wave and wind data were procured from the offshore approach path of the typhoon are very rare and thus researchers are experiencing difficulties in obtaining calibration and verification data of typhoon-generated wave modeling. This paper provides a synthesis of records of observations by the Korea Meteorological Administration and Korea Institute of Ocean Science and Technology on storm waves generated by the typhoons SONGDA, NABI, and SHANSHAN that passed from 2004 to 2006 in order to help researchers interested in typhoon-generated wave numerical modeling. Although the trajectories of typhoon NABI and SHANSHAN were east of the Korea Strait, a significant wave height of 8.3 m was measured at Namhyeongjedo located east of Geojedo. Moreover, an unprecedented significant wave height of 12.2 m was measured for both typhoons at a station 1.4 km away from Yeongil Bay breakwater. Meanwhile, a comparative analysis of data obtained with a ocean data buoy at Geojedo and a Directional Waverider at Namhyeongjedo showed maximum wave heights that were similar but considerably different significant wave heights.

• Journal of the Korean earth science society
• /
• v.40 no.3
• /
• pp.259-271
• /
• 2019

A statistical downscaling method was adopted in order to establish the high-resolution wave prediction system in the East Sea coastal area. This system used forecast data from the Global Wave Watch (GWW) model, and the East Sea and Busan Coastal Wave Watch (CWW) model operated by the Korea Meteorological Administration (KMA). We used the CWW forecast data until three days and the GWW forecast data from three to seven days to implement the statistical downscaling method (inverse distance weight interpolation and conditional merge). The two-dimensional and station wave heights as well as sea surface wind speed from the high-resolution coastal prediction system were verified with statistical analysis, using an initial analysis field and oceanic observation with buoys carried out by the KMA and the Korea Hydrographic and Oceanographic Agency (KHOA). Similar to the predictive performance of the GWW and the CWW data, the system has a high predictive performance at the initial stages that decreased gradually with forecast time. As a result, during the entire prediction period, the correlation coefficient and root mean square error of the predicted wave heights improved from 0.46 and 0.34 m to 0.6 and 0.28 m before and after applying the statistical downscaling method.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.27 no.4
• /
• pp.457-464
• /
• 2021

Cargo securing safety, which is one factor for the safe operation of car ferry ships, has been applied since 2015 and evaluated by comparing the hull motion and securing load capacity generated by waves. To ensure the safe operation of the 3700 ton class car ferry, it is important to analyze the hull acceleration motion based on the sea wave information of the navigation area to determine the cargo securing load that can prevent the movement of cargo. In this study, the meteorological information of three wave buoys installed in Busan and Jeju area was analyzed for the past 5 years. In addition, the hull acceleration was measured in actual sea conditions and compared to that of numerical simulations. Under the condition of a significant wave height of 2.5 m from Feb to Mar, except typhoon seasons, the lateral acceleration was observed to be 1.5 m/s² in real ship measuring and 1.8 m/s² in numerical calculation. It was analyzed to be less than 40% under general weather conditions compared to the high wave warning using an approximate formula for estimating the hull motion by wave height. The cargo securing safety proposed in this study will be widely used based on the actual measuring acceleration with the sea wave height.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.35 no.4
• /
• pp.75-83
• /
• 2023

Apart from implementing hardware solutions like raising the crest freeboard of coastal structures to efficiently counter wave-overtopping, there is a simultaneous requirement for software-driven disaster mitigation strategies. These tactics involve the swift and accurate dissemination of wave-overtopping information to the inland regions of coastal zones, enabling the regulation of evacuation procedures and movement. In this study, a method was proposed to estimate wave-overtopping by utilizing the temporal variation of wave heights exceeding the structure's crown level, with the aim of developing an on-site wave measurement system for providing wave-overtopping information in the field. Laboratory model experiments were conducted on vertical seawall structures to measure wave-overtopping volumes and wave runup heights under different wave conditions and structural freeboard variations. By assuming that the velocity of water inundation on the top of the structure during wave-overtopping events is equivalent to the long-wave velocity, an overtopping discharge coefficient was introduced. This coefficient was utilized to estimate the rate of wave-overtopping based on the temporal changes in wave runup heights measured at the top of the structure. Upon reasonably calculating the overtopping discharge coefficient, it was verified that the estimation of wave-overtopping could be achieved solely based on the wave runup heights.

• KSBB Journal
• /
• v.24 no.2
• /
• pp.122-130
• /
• 2009

Anti-angiogenic mechanism was examined for anti-obesity agents with the extract of P.radix, P.semen, S.hebra and C.furctus through anti-cell adhesion effect and western blot. Cell adhesion molecules, VCAM-1 was supressed with the order of P.radix (0.2 ppm, 125%) > P.semen (0.5 ppm, 100%) > S.hebra (5.0 ppm, 114%) > C. furctus (5.0 ppm, 111.8%), ICAM-1 was inhibited by P.radix (0.25 ppm, 130%) > P.semen (0.5 ppm, 100%) > S.hebra (5.0 ppm, 138%) > C. furctus (5.0 ppm, 66.7%), E-Selectin was also supressed P.radix (0.25 ppm, 100%) > P.semen (1.0 ppm, 128%) > S.hebra (5.0 ppm, 120%) > C. furctus (5.0 ppm, 100.7%). And signal molecules, VE-cadherin was supressed by P.radix and S.hebra, ${\beta}$-catenin was inhibited by P.radix, and Akt was supressed all these 4 kinds of natural products. These P.radix, P.semen, S.hebra and C.furctus were showed the possibility of anti-obesity agents based on anti-angiogenesis.

• Agrochemical news magazine
• /
• v.20 no.1 s.148
• /
• pp.26-29
• /
• 1999