• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.550-559
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• 2019

The sinking of the M/V SEWOL in April 2014 was not a mere marine accident, but a marine catastrophe. This grim case developed into a social tragedy that impinged the national sentiment and communal integrity. It is imperative that thorough provisions and measures be outlined at the national level with regard to massive marine accidents, oil pollution, and natural disasters that might critically affect government affairs. Pivoting on "The Black Swan Theory," a concept of improperly rationalizing a national crisis based on uncertainties, this research assesses a variety of response strategies that minimize the national economic and social damage caused by a large-scale marine disaster. Along with the effort of minimizing any potential defects in each protective barrier, the "Black Swan Detection System of the Marine Disaster" needs to be incorporated to prevent cases wherein such defects lead to an actual crisis. Maritime safety must be systematically unified under a supervisory organization, and a structure for maritime crisis on-scene command and cooperation must likewise be established in order that every force on the scene of a marine disaster may act effectively and consistently under the direction of an on-scene commander.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.583-590
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• 2015

Submarine cable installation is essentials for grid connection between existing power grid and newly produced electricity which will be from offshore wind farm in Southwest sea area of Korea. Especially, submarine cable route and protection method is designed in order to ensure the economical efficiency, workability and stability of submarine cable installation. On this paper, we will give the basic information about the submarine cable route and protection method of offshore wind farm which will be built in Southwest sea area of Korea. For this, we have a numerical simulation at high and low tide based on the third-generation wave model SWAN(Simulating WAves Nearshore) using the long term wave data from Korea Institute of Ocean Science and Technology(KIOST). The results of the study, year mean Hs is 1.03m, Tz is 4.47s and dominant wave direction is NW and SSW When the incident wave direction is NW(Hs: 7.0 m, Tp: 11.76s), the distribution of shallow water design wave height Hs was calculated about 4.0~5.0m at high tide and 2.0~3.0m at low tide. When the incident wave direction is SSW(Hs: 5.84 m, Tp: 11.15s), the distribution of shallow water design wave height Hs was calculated about 3.5~4.5m at high tide and 1.5~2.5m at low tide. The wave direction on a dominant influence in the section of longitude UTM 249749~251349(about 1.6 km) and UTM 251549~267749(about 16.2 km) in the submarine cable route are each NW and SSW. Prominently, wave focusing phenomenon appears between Wi-do and Hawangdeung-do, in this sea area is showing a relatively high wave hight than the surrounding sea areas.

• Journal of Navigation and Port Research
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• v.33 no.10
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• pp.703-707
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• 2009

In order to evaluate applicability of cylindrical slit type block breakwater to the field water, which was designed from the previous physical model study, it is analyzed the calmness of harbor area by the numerical model experiment. For a small fishery port in southern coast of Korea a SWAN model using the wave action balance equation was formulated. The reflection and transmission coefficients induced by the physical model test were introduced to the numerical model. The model response with cylindrical slit type breakwater was compared with the impermeable breakwater case and the possibility of water quality improvement through the water circulation by the new structure was investigated. For numerical simulation, parameters of deepwater design wave from the prediction report II for overall deepwater design wave by KORDI were used and wind parameters from the 50years return period observed for 37years(1970~2006) were adopted in the numerical model. The response of west breakwater in Mijo port applying the NE and NNE waves, which were dominant in this area, was analyzed. It was found that the transmission characteristic of designed cylindrical slit breakwater was well presented in the numerical model.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.231-233
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• 2010

최근 어항에도 친환경항만을 건설하기 위한 노력이 국제적으로 확산되고 있으며, 우리나라에서도 어항의 정비 및 재개발부분에서 적극적으로 수질개선을 위한 기술 적용이 본격화 되고 있다. 본 연구는 우리나라 남해의 소규모 어항 및 해수욕장에 슬릿형 해안 구조물이 시공된 실해역의 실측자료와 수치해석을 통해 현장적용성의 분석을 수행하였다. 수치실험으로는 파랑작용 평형방정식을 이용하는 SWAN 모델을 구성하고 수리모형실험에서 분석된 실린더 슬릿형 방파제의 반사와 투과계수를 모텔에 도입하였다. 수치실험은 한국해양연구원의 전해역 심해설계파 추정 보고서 II (2005)중의 심해설계파 제원을 사용하였으며, 대상해역의 1970년~2006년 (37년간) 관측된 연최대 풍속자료를 이용하여 모델에 반영하였다. 설리항에서 S, SSE, SE계열의 파랑의 내습에 대한 분석을 수행하였으며, 그 결과 구조물이 항내에서 정온도가 유지되며 해수순환에도 이점이 있음을 현장관측 자료분석과 수치실험결과를 통하여 확인할 수 있었다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.4
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• pp.180-188
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• 2017

Recently, as the strength of winds and waves increases due to the climate change, abnormal waves such as swells have been also increased, which results in the increase of downtime events of loading/unloading in a harbour. To reduce the downtime events, breakwaters were constructed in a harbour to improve the tranquility. However, it is also important and useful for efficient port operation by predicting accurately and also quickly the downtime events when the harbour operation is in a limiting condition. In this study, numerical simulations were carried out to calculate the wave conditions based on the forecasted wind data in offshore area/outside harbour and also the long-term observation was carried out to obtain the wave data in a harbour. A forecasting method was designed using an auto-regressive (AR) and artificial neural networks (ANN) models in order to establish the relationship between the wave conditions calculated by wave model (SWAN) in offshore area and observed ones in a harbour. To evaluate the applicability of the proposed method, this method was applied to predict wave heights in a harbour and to forecast the downtime events in Pohang New Harbour with highly complex topography were compared. From the verification study, it was observed that the ANN model was more accurate than the AR model.

• Journal of Chest Surgery
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• v.32 no.5
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• pp.422-427
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• 1999

Background: Tachycardia induced heart failure model would be the model of choice for the dilated cardiomyopathy. This more closely resembles the clinical syndrome and does not require major surgical trauma, myocardial ischemia and pharmacological or toxic depression of cardiac function. When heart failure is progressive, application of new surgical procedures to the faling heart is highly risky. It has been shown that recovery trajectory from heart failure is a new method in decreasing animal mortality. The purpose is to establish the control datas for recovery trajectory in the canine heart failure model. Material and Method: 21 mongrel dogs were studied at 4 stages(baseline, at the heart failure, 4 and 8 weeks after recovery). Heart failure was induced during 4 weeks of continuous rapid pacing using a pacemaker. Eight weeks of trajectory of recovery period was allowed. Indices of left ventricular function and dimension were measured every 2 weeks and the hemodynamics were measured by use of Swan-Ganz catheterization and thermodilution method every 4 weeks. Values were expressed as mean${\pm}$standard deviation. Result: 4(20%) dogs died due to heart failure. Left ventricular end-diastolic volume at the 4 stages were 40.8${\pm}$7.4, 82.1${\pm}$21.1, 59.9${\pm}$7.7 and 46.5${\pm}$6.5ml. Left ventricular end-systolic volume showed the same trend. Ejection fractions were 50.6${\pm}$4.1, 17.5${\pm}$5.8, 36.3${\pm}$7.3, and 41.5${\pm}$2.4%. Blood pressure and heart rate showed no significant changes. Pressures of central vein, right ventricle, pulmonary artery, and pulmonary capillary wedge showed significant increase during the heart failure period, normalizing at the end of recovery period. Stroke volumes were 21.5${\pm}$8.2, 12.3${\pm}$3.5, 17.9${\pm}$4.6, and 15.5${\pm}$3.4ml. Blood norepinephrine level was 133.3${\pm}$60.0pg/dL at the baseline and 479.4${\pm}$327.3pg/dL at the heart failure stage(p=0.008). Conclusion: Development of tachycardia induced heart failure model is of high priority due to ready availability and reasonable amenability to measurements. Recovery trajectory after cessation of tachycardia showed reduction of cardiac dilatation and heart function. Application of new surgical procedures during the recovery period could decrease animal mortality.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.67-74
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• 2001

A field experiment was carried out to determine the effects of chemical/mechanical treatments at mowing on the field drying rate and hay quality of alfalfa(Medicago sativa L., cv. Vernal) and spring oats(Avena satvia L., cv. Swan). The chemical drying agent of 2% $K_2CO_3$, mechanical mower conditioning, and no treatment(control) were treated for hastening hay-making in the spring of 1997. The forages were harvested at early bloom stage in alfalfa and heading stage in oats. After field dry, square bales were made by hay baler, and the dry matter(DM) loss, visual estimation and nutritive value of hay were evaluated after storing two months. The field drying rates of alfalfa and oats were high at mechanical treatment, but the drying effectiveness of chemical agents alone was very low. With mower conditioning, the duration of field dry was shortened by 1 day compared with control. therefore, mower conditioning enhance the field drying rate of alfalfa and oats. The DM loss of alfalfa and oats hay was reduced by mechanical treatment, but the efficiency by chemical alone was low. The visual score(leafiness, green color, odor and softness) of hay at mechanical treatment was slightly higher than that of chemical and control. The nutritive value(ADF, NDF, in vitro digestibility, and relative feed value) of hay was also high with treatment of mechanical, but those of chemical alone were similar compared with control. The nutritive value of hay after two months in both alfalfa and oats was decreased when compared with at harvest.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.2
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• pp.126-132
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• 2010

An approach to calculating expected damage of breakwater assisted by artificial neural network was developed. Wave height in front of a breakwater was predicted by a trained artificial neural network with inputs of wave height in deep ocean and tidal level. Prediction results by the neural network can be comparable to that by professional numerical model for wave transformation. Using the wave prediction neural network, it was very easy and fast to obtain a number of significant waves at breakwater and finally analysis time for expected damage can be shortened. In addition, the effect of considering tidal level in the calculation of expected damage was revealed by comparing the expected damages with and without tidal variation. Therefore, it was pointed out that tidal variation should be considered to improve prediction accuracy.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.599-607
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• 2015

The purpose of this study is to reproduce long-term wave fields in coastal waters of Korea based on wave hind-casting modelling and discuss its applications. To validate wind data(NCEP, ECMWF, JMA-MSM), comparison of wind data was done with wave buoy data. JMA-MSM predicted wind data with high accuracy. But due to relatively longer period of ECMWF wind data as compared to that of JMA-MSM, wind data set of ECMWF(2001~2014) was used to perform wave hind-casting modelling. Results from numerical modelling were verified with the observed data of wave buoys installed by Korea Meteorological Administration(KMA) and Korea Hydrographic and Oceanographic Agency(KHOA) on offshore waters. The results agree well with observations at buoy stations, especially during the event periods such as a typhoon. Consequently, the wave data reproduced by wave hind-casting modelling was used to obtain missing data in wave observation buoys. The obtained missing data indicated underestimation of maximum wave height during the event period at some points of buoys. Reasons for such underestimation may be due to larger time interval and resolution of the input wind data, water depth and grid size etc. The methodology used in present study can be used to analyze coastal erosion data in conjunction with a wave characteristic of the event period in coastal areas. Additionally, the method can be used in the coastal disaster vulnerability assessment to generate wave points of interest.

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.4
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• pp.323-328
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• 1998

A field experiment was carried out to determine the effects of chemical and mechanical treatment at mowing on the field drying rate and hay quality of autumn oat (Avena sativa L.). The chemical drying agent/mower conditioner ($K_2CO_3$ 2%, conditioning, $K_2CO_3$ 2% + conditioning and control) were treated at different harvest stages (late boot, heading and bloom stage) for hastening hay manufacture in the autumn of 1996. After field dry, square bales were made by hay baler, and the dry matter(DM) loss and visual estimation of oat hay were evaluated after storing two months. In general, the field drying rate of oat was slow, regardless of harvest stage. Mechanical and chemical + mechanical treatment were effective, but the effectiveness of chemical alone was very low. With mower conditioning, the duration of field dry was shortened by 2 days compared with control. The DM loss of hay was higher at boot stage(51.4%) than at heading stage (21.1%), and the DM loss was reduced by mechanical and chemical + mechanical combined treatment. The visual score (leafiness, green color, odor and softness) of hay after storing was high in mechanical and chemical + mechanical, but the score by chemical alone was very low. The nutritive value (ADF, NDF, digestibility, and relative feed value) of hay was also high with treatment of mechanical and chemical + mechanical, but the quality by chemical alone was similar compared with control. In conclusion, mower conditioning can enhance the field drying rate of autumn oat, but the drying efficiency of the chemical drying agent was very low. However, it is suggested that hay-making of oat in autumn is very hard though using mower conditioner.