• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4B
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• pp.365-376
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• 2009

The importance of resonable treatment of tide characteristics has been shown by Kweon, et al. (2005, 2006) for the crest elevation estimation because of a big difference of tidal elevation along Korean coast. For the procedure of crest elevation design, the expected overtopping probability (EOP) was estimated by Kweon, et al. (2006). The comparisons on each sea showed that EOP was lower east, south and west sea in order. The results involved the assumption that the tide and design level wave height meet any time in a year. However, big waves mainly occur in summer or winter in Korean coast, the study focuses on the encounter probability of big waves and seasonal tide level. A theory of the encounter probability is not derived by the present study but it shows reasonable acceptability of the proposed scenario in which the expected overtopping probability could be an index for the crest elevation estimation in Korean coast. The calculation based on the scenario gives the possibility range for the crest elevation estimation which has no tendency of each sea along Korean peninsular. The range is within the expected overtopping probability of 1% in the whole coast of Korea.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.3
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• pp.247-254
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• 2008

The double-peak normal distribution function (DPDF) suggested by Cho et al.(2004) has the problems that the extremely high and low tidal elevations are frequently generated in the Monte-Carlo simulation processes because the upper and lower limits of the DPDF are unbounded in spite of the excellent goodness-offit results. In this study, the modified DPDF is suggested by introducing the upper and lower value parameters and re-scale parameters in order to remove these problems. These new parameters of the DPDF are optimally estimated by the non-linear optimization problem solver using the Levenberg-Marquardt scheme. This modified DPDF can remove completely the unrealistically generated tidal levations and give a slightly better fit than the existing DRDF. Based on the DPDF's characteristic power, the over- and under estimation problems of the design factors are also automatically intercepted, too.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4B
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• pp.399-404
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• 2006

Kweon et al. (2004) proposed the calculation method of Expected Overtopping Probability (EOP) that considers the occurrence frequency distribution of real sea tide. The method was applied for the comparison of the EOP of Mukho and Busan sea. They showed that the tide occurrence frequency had a great effect on the EOP and the value becomes smaller as the standard deviation of the frequency comes bigger. The present study following Kweon et al.'s method estimates the EOP characteristic of the crest elevation located on East, South, and West sea. The study shows that the EOP becomes smaller following East, South, West sea in order.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.5
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• pp.278-284
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• 2014

Water temperature due to climate change can be estimated using the air temperature because the air and water temperatures are closely related and the water temperatures have been widely used as the indicators of the environmental and ecological changes. It is highly necessary to estimate the frequency distribution of the air and water temperatures, for the climate change derives the change of the coastal water temperatures. In this study, the distribution function of the air temperatures is estimated by using the long-term coastal air temperature data sets in Korea. The candidate distribution function is the bi-modal distribution function used in the previous studies, such as Cho et al.(2003) on tidal elevation data and Jeong et al.(2013) on the coastal water temperature data. The parameters of the function are optimally estimated based on the least square method. It shows that the optimal parameters are highly correlated to the basic statistical informations, such as mean, standard deviation, and skewness coefficient. The RMS error of the parameter estimation using statistical information ranges is about 5 %. In addition, the bimodal distribution fits good to the overall frequency pattern of the air temperature. However, it can be regarded as the limitations that the distribution shows some mismatch with the rapid decreasing pattern in the high-temperature region and the some small peaks.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.2
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• pp.72-80
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• 2014

The approximately highest high water(AHHW), which has been used frequently as a basis of the design sea level, has not only ambiguous return period but also spatio-temporal problems induced by sea level rise and the spatial variability of tidal characteristics. The ratios of 4 major constituents with other constituents were investigated. In addition, tidal data were analyzed by probability density function. The temporal variability may be cured by using the latest tidal data. And the AHHW at summer was examined to lessen the spatial variability. The results show that the design sea levels need to increase by 10 cm or more at the Southern Coast and by 15~25 cm at the East Coast.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.387-387
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• 2020

본 연구에서는 LIP에 의한 극한강우로부터 발생되는 극한홍수량을 산정한다. Huff 형 강우시간 분포를 기후변화 시나리오별로 적용하고, 원전주변지역에서의 상세한 토지이용조건의 변화를 고려하여 빈도별 홍수량을 산정한다. 외부침수해석의 정교화를 위한 상세 지형자료를 구축하고, 원자력발전소 부지의 상세 DEM 자료를 생성한다. 이를 위해서 원자력발전소 부지에서 건물, 연석, 도로 등의 영향을 분석하고 토지이용상황에 따른 조도계수를 산정한다. 또한 원전지역에서의 외부침수재해도 분석을 위해서 국립해양조사원에서 검토한 기후변화를 고려한 조위분석 자료를 외부경계조건으로 설정한 후 부지에 대한 2차원 수리분석을 실시한다. 침수심, 침수유속, 침수시간, 침수동압력 분석 등 2차원 침수해석결과를 바탕으로 발생빈도별 침수심, 침수강도 등의 정량적인 분석을 통해서 빈도별 재해도 곡선을 개발한다. 그리고 원전지역에서의 외부 침수에 대한 대표적인 재해도 곡선을 산정하기 위하여 재현기간별 지속시간에 따른 침수심을 분석하고 정리한다. 재현기간별 침수심에 대해 확률 분포형을 적용하기 위해서 AIC검증을 통한 분포형의 적합성을 분석을 실시한다. 또한 재현기간별 지속시간에 따른 침수심들 간의 상관관계를 분석하여 분포형에 적용한다. 적용된 분포형을 몬테칼로 시뮬레이션을 통한 대표적인 확률론적 외부 침수 재해도 곡선을 산정한다. 본 연구를 바탕으로 원전 부지 및 그 부속 시설물(SSC)의 홍수방지 기능과 홍수 대비 시설물에 대한 적용 절차의 신뢰성, 홍수 저감 및 대응 전략에 대한 정량화가 가능하여 원전 홍수 위험에 대한 정량적인 평가 지원이 가능하겠다. 고려할 외부 홍수와 관련된 원전 내부시설 및 장비에 대한 상세한 모델링 절차, 특정 시나리오에 대한 홍수 방지 및 예방과 관련한 SSC의 정량화, 홍수저감 활동과 관련된 통제실 외부 시설물에 대한 수동 조작에 대한 평가가 이루어질 수 있겠다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.5
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• pp.312-317
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• 2016

The submersion and emersion patterns are key factors that directly influence the habitat environment of the coastal plants and animals. In this study, the coasts are divided into five zones (zones 1, 2, 3, 4, and 5 - not flooded, flooded once, flooded and exposed to air twice, exposed to air once, continuously flooded in the day, respectively) based on the patterns using tidal elevation data at the major eight stations and the domestic and international reference tidal levels, i.e., AHHW, ALLW, HAT and LAT, are also estimated to analyse the characteristics of the five distinct zones. Based on the results, the frequency of the zone 3 are dominant and forms from 87.2% to 88.2% (nearly constant) irrelevant with the tidal ranges at all stations. The taking-up percentages of the zones 2 and 4 show nearly constant, below 4% and over 8%, respectively. In Pohang station classified as the mainly diurnal tide, the percentages are decreased to 1.4% in zone 2 and increased to 10.8% due to the effects of the annual and semi-annual tidal components.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.3
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• pp.103-113
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• 2018

Tide-surge characteristics of the West/South domestic coasts were analyzed with a tool of EST (empirical simulation technique). As a result, stations of Incheon, Gunsan, Mokpo and Busan are categorized as tide-dominant coasts, while Yeosu, Tongyoung and Busan are as surge-dominant coasts. In the tide-dominant coasts, extreme sea level of less than 50-yr frequency is formed without typhoon-surge, while only 10-yr extreme sea level is formed in the surge-dominant coasts. As the results of casual condition of extreme sea level formation considering the relative degree of surge on tide, the regional characteristics were detected also. Three methods for estimating the design tide level were compared. The AHHW method shows an unrealistic outcomes of the concern of over estimate design. Furthermore, the probability distribution function method has been concerned as causing missing data if a huge typhoon occurs in a neap tide or a low tide. To cope with these drawbacks, the applicability of the EST method is proved to be suitable especially in tide-dominant coasts.