• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.511-518
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• 2019

This study aimed to extract the priority safety improvement factors for coastal passenger ships and analyze the perception gap between groups. To extract the improvement factors, we formed an expert group with maritime safety supervisors, passenger-ship safety inspectors (PSIs), and captains of passenger ships, and then conducted a Delphi survey. We found, using a hierarchy process, that the improvement factors were divided into three factors in Level 1 and ten factors in Level 2. For the relative importance analysis using the AHP (Analytic Hierarchy Process) model, we also formed two groups: an inspector group with maritime safety supervisors and PSIs, and an examinee group with safety managers, captains, and crews. Consequently, the factors of designation of public transportation for passenger ships and supporting the welfare of the crew were evaluated as the most important among the extracted factors. We conducted a t-test for the analysis of the perception gap between the two groups. Three perception gaps were found: increasing the inspection personnel, strengthening the qualification of the inspection personnel, and expanding the safety operation center. The result of this study will be useful for improving the safety policy of coastal passenger ships.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.478-478
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• 2022

섬진강은 하굿둑이 없는 열린 하구로서 하구로부터 약 21km까지 조석의 영향을 받아 강물의 염도가 시간에 따라 변하는 환경이다. 오랫동안 섬진강 하구는 다양한 원인으로부터 바다화로 대표되는 염하구 문제가 지역 현안 사항으로 제기되어 왔다. 상류에서의 용수사용 증가로 인한 하천 유하량 감소 또한 그 원인들 중 하나로 판단됨에 따라 실제 하구까지 내려오는 하천유량과 바다로부터 유입되는 해수를 구분하여 정량화하는 연구가 필요한 사안이다. 본 연구의 목적은 섬진강 수계 하구에서의 다양한 생태환경을 보전하기 위한 적정 염분유지가 요구됨에 따라 섬진강하구 염분계측기(섬진강대교)를 설치하여 염분농도를 관측하고 하천유량, 하천취수 및 해양조위에 따른 염분농도 변화를 모의하여 하천유량과 염분과의 관계를 제시하고자 하였다. 본 연구에서는 EFDC(Environmental Fluid Dynamics Code) 수치모델을 이용하여 상류로는 구례군(송정리) 수위관측소부터 하류로는 여수해만 및 문의리까지의 구역을 설정하고 광양조위, 하동수위 및 고정식 염분 계측기 관측염분농도 자료를 이용하여 수치모델링의 재현성을 검증하였다. 검증 결과, 결정계수(R²)는 0.87(하동수위), 0.93(광양조위), 0.56(섬진강대교 염도)를 나타냈다. 모델 검보정 후 하천유량에 따른 염분변화 실험을 실시하여 염분농도 거동을 분석하였다. 모델 결과, 섬진강하구에서의 염분거동은 소조기때 염분체류 현상으로 인해 대조기 거동과는 큰 차이를 나타냈다. 따라서, 모델링 결과를 이용한 유량-염분 조견표는 각각 대조기와 소조기로 구분하여 산정하였다. 대조기때는 송정유량이 10톤/초의 평균갈수량이 흐를 경우 다압에서의 취수량이 2.52톤/초 ~ 4.63/초로 증가할수록 18.8psu ~ 19.9psu로 증가하였다. 소조기의 경우는 25.5psu ~ 25.7psu로 대조기와 비교하여 크게 증가됨을 나타냈다. 본 연구의 결과는 객관적인 생태환경 보전을 위한 적정염분농도 범위가 도출된다면 이를 유지하기 위한 필요유량과 필요유량을 확보하기 위한 장단기적인 대책수립이 가능할 것으로 기대된다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.5
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• pp.407-428
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• 1991

The eastern coastal area having variability of climate is located within Taebaek mountain range and the east coast of Korea. It is therefore ease to cause the wind damages in paddy field during rice growing season. The wind damages to rice plant in this area were mainly caused by the Fohn wind (dry and hot wind) blowing over the Taebaek mountain range and the cold humid wind from the coast. The dry wind cause such as the white head, broken leaves, cut-leaves, dried leaves, shattering of grain, glume discolouration and lodging, On the other hand the cold humid wind derived from Ootsuku air mass in summer cause such symptom as the poor rice growth, degeneration of rachis brenches and poor ripening. To minimize the wind damages and utilize as a preparatory data for wind injury of rice in future, several experiments such as the selection of wind resistant variety to wind damage, determination of optimum transplanting date, improvement of fertilizer application methods, improvement of soils and effect of wind break net were carried out for 8 years from 1982 to 1989 in the eastern coastal area. The results obtained are summarized as follows. 1. According to available statisical data from Korean meteorological services (1954-1989) it is apperent that cold humid winds frequently cause damage to rice fields from August 10th to September 10th, it is therefore advisable to plan rice cultivation in such a way that the heading date should not be later than August 10th. 2. During the rice production season, two winds cause severe damage to the rice fields in eastern coastal area of Korea. One is the Fohn winds blowing over the Taebaek mountain range and the other is the cold humid wind form the coast. The frequency of occurrence of each wind was 25%. 3. To avoid damage caused by typhoon winds three different varieties of rice were planted at various areas. 4. In the eastern coastal area of Korea, the optimum ripening temperature for rice was about 22.2$^{\circ}C$ and the optimum heading date wad August 10th. The optimum transplanting time for the earily maturity variety was June 10th., medium maturity variety was May 20th and that of late maturity was May 10th by means of growing days degree (GDD) from transplanting date to heading date. 5.38% of this coastal area is sandy loamy soil while 28% is high humus soil. These soil types are very poor for rice cultivation. In this coastal area, the water table is high, the drainage is poor and the water temperature is low. The low water temperature makes it difficult for urea to dissolve, as a result rice growth was delayed, and the rice plant became sterile. But over application of urea resulted in blast disease in rice plants. It is therefore advise that Ammonium sulphate is used in this area instead of urea. 6. The low temperature of the soil inhibits activities of microorganism for phosphorus utilization so the rice plant could not easily absorb the phosphorus in the soil. Therefore phosphorus should be applied in splits from transplanting to panicle initiation rather than based application. 7. Wind damage was severe in the sandy loamy soil as compared to clay soils. With the application of silicate. compost and soil from mointain area. the sand loamy soil was improved for rice grain colour and ripening. 8. The use of wind break nets created a mocro-climate such as increased air. soil and water temperature as well as the reduction of wind velocity by 30%. This hastened rice growth, reduced white head and glume discolouration. improved rice quality and increased yield. 9. Two meter high wind break net was used around the rice experimental fields and the top of it. The material was polyethylene sheets. The optimum spacing was 0.5Cm x 0.5Cm. and that of setting up the wind break net was before panicle initiation. With this set up, the field was avoided off th cold humid wind and the Fohn. The yield in the treatment was 20% higher than the control. 10. After typhoon, paddy field was irrigated deeply and water was sprayed to reduce white head, glume discolouration, so rice yield was increased because of increasing ripening ratio and 1, 000 grain weight.