• 한국수산과학회지
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• 제56권5호
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• pp.615-625
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• 2023

This study evaluated the bacteriological safety of seawater and abalone produced in Uisin-myeon, Jindo-gun from September 2020 to December 2022 and calculated the effect of inland pollution sources on seawater and abalone. We surveyed 33 stations for seawater, 4 stations for abalone, and 7 stations for discharge water of major inland pollutants. We analyzed the coliform group, fecal coliform and Escherichia coli (E. coli) as bacteria indicators. In 924 seawater samples, the geometric mean of the coliform group and fecal coliform were <1.8-5.6 MPN/100 mL and <1.8-2.7 MPN/100 mL, respectively. The estimated 90^th percentile range for the coliform group and fecal coliform were <1.8-42 MPN/100 mL and <1.8-8.4 MPN/100 mL, respectively. The fecal coliform and E. coli levels for 107 abalone were <18-460 MPN/100 g and <18-78 MPN/100 g respectively. Moreover, the analyzed standard plate count was <30-7,700 CFU/g. The fecal coliform level and diffusion area in 7 inland pollutants were <1.8-3,300,000 MPN/100 mL and 2-2,500 m, respectively. The bacteriological safety of seawater and abalone in Uisin-myeon, Jindo-gun, was demonstrated to be a designated area according to Korean standards, a conditionally approved area per US standards, and Class A according to EU standards.

• 한국전산유체공학회지
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• 제6권1호
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• pp.56-62
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• 2001

A high speed train passing through a station may have undesired effects to passengers on platform due to abrupt pressure transients. Therefore it is very important to reduce the possible degree of danger by installing partition walls in passing lanes in designing the stations having passing train. In the present study, a pressure load to a passenger on platform is studied for the cases of various heights of the partition wall to assess the effectiveness of the wall on the passenger safety. From the results, it is seen that the pressure load on a passenger may be largely reduced by the partition wall. The heights of the partition wall for various passing speed are also studied based on the safety regulation.

• 한국항해학회지
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• 제18권4호
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• pp.155-169
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• 1994

The minimum temperatures are important element in the daily human life, the climatic classification, and so on. In this study, the authors aim to make an analysis the distribution characteristics of minimum temperatures of 95 weather stations in Korea by using the Climatological Standard Normals of Korea VolumeI, VolumeII, and the Climatological Standard Normals of North Korea. The important results are as follows 1) The daily, fifthly, and tenthly minimum temperatures show the highest rate of occurrance on 14th of January( Occurrance rate : 56.6% ), 16~20th of January( 37.6% ), and the middle ten days of January( 82.1% ) respectively. 2) In the regional distribution of minimum temperatures in winter, the values of northern part, inland area, and west coastal region are lower than those of southern, coastal, and east coastal regions respectively. And, bigger cities and industrial area( Seoul, Incheon, Daejeon, Daegu, etc. ) have larger values than the its vicinities. 3) When the daily minimum temperature is $0^{\circ}C$ and less, the days of northern part, inland area, and wests coastal region are higher than those of southern, coastal, and east coastal regions respectively.

• 농업과학연구
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• 제46권1호
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• pp.137-149
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• 2019

Accurate estimation of reference evapotranspiration (RET) is important to quantify crop evapotranspiration for sustainable water resource management in hydrological, agricultural, and environmental fields. It is estimated by different methods from direct measurements with lysimeters, or by many empirical equations suggested by numerous modeling using local climatic variables. The potential to use some such equations depends on the availability of the necessary meteorological parameters for calculating the RET in specific climatic conditions. The objective of this study was to determine the proper RET equations using limited climatic data and to analyze the temporal and spatial trends of the RET in South Korea. We evaluated the FAO-56 Penman-Monteith equation (FAO-56 PM) by comparing several simple RET equations and observed small fan evaporation. In this study, the modified Penman equation, Hargreaves equation, and FAO Penman-Monteith equation with missing solar radiation (PM-Rs) data were tested to estimate the RET. Nine weather stations were considered with limited climatic data across South Korea from 1973 - 2017, and the RET equations were calculated for each weather station as well as the analysis of the mean error (ME), mean absolute error (MAE), and root mean square error (RMSE). The FAO-56 PM recommended by the Food Agriculture Organization (FAO) showed good performance even though missing solar radiation, relative humidity, and wind speed data and could still be adapted to the limited data conditions. As a result, the RET was increased, and the evapotranspiration rate was increased more in coastal areas than inland.

• Ocean and Polar Research
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• 제36권3호
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• pp.209-223
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• 2014

The community structure of benthic meiofauna was investigated from seasonal surveys at seventeen stations off the Saemangeum area, in 2007. Ten meiofaunal taxa were identified. Nematodes were the dominant faunal group in all seasons and harpacticoids were dominant only at a few stations. The mean density of meiofauna was 383 indiv. $10cm^{-2}$, highest in May and November (434 indiv. $10cm^{-2}$), lowest in February (284 indiv. $10cm^{-2}$). Meiofaunal mean biomass was $80.49{\mu}gC{\cdot}10cm^{-2}$, highest in November ($99.54{\mu}gC{\cdot}10cm^{-2}$), lowest in February ($51.56{\mu}gC{\cdot}10cm^{-2}$). Cluster analysis revealed that the study area was composed of three benthic meiofaunal communities. There were significant correlations between major meiofaunal groups and sediment composition and the concentrations of heavy metals. The abundance of harpacticoids are positively correlated with silt (0.559, p < 0.01) and clay (0.340, p < 0.01), and negatively correlated with sand (-0.548, p < 0.01). Harpacticoids also showed positive correlations with heavy metals. The community structure of meiofauna in the study area varied seasonally in response to the change of sediment composition.

• 한국농공학회지
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• 제43권3호
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• pp.56-65
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• 2001

In interpreting stream water quality data, scientific or statistical mehtods should be employed. Classical parametric statistical methods may not be adopted in analyzing water quality data, due to the violation of normality. In this study, nonparametric statistical methods, such as Kruskal-Wallis test and Mann-Whitney test, were used in comparing water quality data from several monitoring stations. Water quality data used are those collected Bokha watershed, located in Ichon-city, Kyonggi province. Based on the test results, domestic sewage is the major pollution source. A couple of sub-watersheds with a large number of livestock do not show significant differences in water quality parameters. It should be noted that comparison of mean values of water quality parameters is difficult to relate water quality with watershed characteristics. The results also indicate that livestock farming does not significantly affect the water quality.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2009년도 춘계학술발표회 논문집
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• pp.49-53
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• 2009

본 연구에서는 현재 활발한 연구가 진행되고 있는 고정밀 지오이드 모델 개발에 있어서 중요한 요소 중 하나인 지상중력자료를 획득하기 위해 상대중력계를 이용하여 중력을 측정 하였다. 1등 수준노선 총 58점의 수준점에 대하여 상대중력측량을 실시하였고 이렇게 얻어진 중력값으로부터 지구조석보정 및 기계고 보정 후 자유망조정 방법을 이용하여 중력성과를 계산하였다. 이와 같은 방법을 통해 얻어지는 지상중력자료들은 고정밀 지오이드 모델 개발에 큰 기여를 할 것으로 판단된다.

• 한국수자원학회논문집
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• 제42권5호
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• pp.385-396
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• 2009

본 연구에서는 도시화나 지리지형적 특성에 따른 강수량의 분포와 추세를 분석하였다. 이를 위하여 서울을 포함하여 전국 56개 기후관측지점에서 1973년부터 2006년까지의 강수량 자료를 수집하여 분석을 실시하였다. 분석을 위하여 계절적 영향을 고려하여 1월, 4월, 7월 그리고 10월의 월평균 일별과 연평균 일별 강수량 추세를 분석하였다. 그리고 이들 연구지역에 대해서 GIS 분석을 이용하여 지리지형적 특성을 파악하였고, 도시화 정도를 파악하기 위하여 토지피복자료를 분석하였다. 연구결과 연평균 일별 강수량 추세는 대부분의 연구지역에서 증가하고 있으며, 4월과 10월의 강수량은 감소추세에 있고, 1월과 7월의 경우 증가추세에 있는 것으로 나타났다. 도시화 영향을 고려할 때, 강수량 변화는 연별이나 7월의 경우 증가추세를 보이나 1, 4, 10월 강수량의 경우 감소추세를 보였다. 또한 도시화율이나 해안 근접성과 비교하여 연구지역의 평균고도는 연평균 및 월평균 강수량 추세에 가장 중요한 영향을 미치고 있음을 알 수 있었다.

• 한국수자원학회논문집
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• 제56권12호
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• pp.981-992
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• 2023

최근 전세계적인 기후변화의 영향으로 강우가 집중되고 강우강도가 강해짐에 따라 홍수피해의 규모를 증가시키고 있다. 과거에 관측되지 않았던 규모의 비가 내리기도 하고, 기록되지 않았던 장기간의 장마가 발생하기도 한다. 이러한 피해들은 아세안 국가에도 집중되고 있으며, 태풍 및 집중호우로 인해 침수의 빈번한 발생과 함께 많은 사람들이 영향을 받고 있다. 특히, 인도네시아 찌따룸강 상류 유역에 위치한 반둥 지역은 분지 형태의 지형학적 특성을 가지고 있어서 홍수에 매우 취약한 실정이다. 이에 공적개발원조(ODA)를 통해 2017년에 찌따룸강 상류(Upper Citarum River) 유역에 대하여 홍수예경보시스템을 구축되었고, 현재 운영중에 있다. 그럼에도 불구하고, 찌따룸강 상류 (Upper Citarum River) 지역은 홍수발생시 인명 및 재산피해의 위험에 여전히 노출되어 있어 신속하고 정확한 홍수예경보의 실시를 통해 피해를 경감시키는 노력이 지속적으로 필요한 실정이다. 따라서 본 연구에서는 찌따룸강 상류의 Dayeuh Kolot 지점을 목표관측소로 하고, 강우관측소 4개소와 수위관측소 1개소의 10분 단위 수문자료를 수집하여 인공지능 기반의 하천홍수위예측모형을 개발하였다. 6개 관측소의 2017년 1월부터 2021년 1월까지의 10분 단위 수문관측자료를 활용하여 선행예보시간 0.5, 1, 2, 3, 4, 5, 6시간에 대해서 학습, 검증, 시험을 수행하였으며 인공지능알고리즘으로는 LSTM을 적용하였다. 연구결과 모든 선행예보시간에 대해 모형적합도 및 오차에서 좋은 결과를 나타냈으며, 학습자료 구축조건에 따른 예측정확도를 검토한 결과 참조관측소가 적은 경우에도 모든 관측소를 활용하는 경우와 유사하게 예측정확도를 확보하는 것으로 나타나 효율적인 인공지능 기반 모형 구축에 활용될 수 있을 것으로 기대된다.

• Journal of the korean society of oceanography
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• 제34권2호
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• pp.122-131
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• 1999

This study examined the relationship between the sediment pollution and the occurrence of polychaetes in a heavily polluted saltwater lake, Lake Shihwa on the west coast of Korea, separated from the sea by a dike in 1994. The species composition of polychaete assemblage was compared with that found off the lake in Kyeonggi Bay. Environmental variables investigated both in and off the lake were the grain size distribution, chemical oxygen demand(COD) and metal concentrations (Al, Fe, Mn, V, Co, As, Pb, Cr and Cu) in the sediment. We sampled sediments at 10 stations in the lake and 25 stations in Kyeonggi Bay using a modified van Veen grab. The levels of COD, chromium, and copper in sediments were much higher in Lake Shihwa than in Kyeonggi Bay. Differences in the species composition were found along the pollution gradient. An azoic zone was observed in the most heavily polluted area at the upper reach of the lake and the Polydora ligni zone in the center of the lake. Bottom fauna were diverse in Kyeonggi Bay; however, Heteromastus filiformis predominated in the organically enriched sediment. The density of dominant species differed along the pollution gradient. The highest density or H. filiformis was round at the COD level or around 5.8 mg/g. The COD level in the sediment where P. ligni predominated was tow-fold higher than that where H. filiformis occurred in large numbers. The chromium and copper contents at which P. ligni showed a maximum abundance were 120 mg/kg and 127 mg/kg, respectively. The density of H. filiformis was highest at concentrations of 56 mg/kg chromium and 13 mg/kg copper.