• Journal of Astronomy and Space Sciences
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• 제28권4호
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• pp.291-298
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• 2011

The atmospheric infrared sounder (AIRS) sensor loaded on the Aqua satellite observes the global vertical structure of atmosphere and enables verification of the water vapor distribution over the entire area of South Korea. In this study, we performed a comparative analysis of the accuracy of the total precipitable water (TPW) provided as the AIRS level 2 standard retrieval product by Jet Propulsion Laboratory (JPL) over the South Korean area using the global positioning system (GPS) TPW data. The analysis TPW for the period of one year in 2008 showed that the accuracy of the data produced by the combination of the Advanced Microwave Sounding Unit sensor with the AIRS sensor to correct the effect of clouds (AIRS-X) was higher than that of the AIRS IR-only data (AIRS-I). The annual means of the root mean square error with reference to the GPS data were 5.2 kg/$m^2$ and 4.3 kg/$m^2$ for AIRS-I and AIRS-X, respectively. The accuracy of AIRS-X was higher in summer than in winter while measurement values of AIRS-I and AIRS-X were lower than those of GPS TPW to some extent.

• 해양환경안전학회지
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• 제20권3호
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• pp.270-276
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• 2014

Seasonal characteristics of water and sediment qualities and potential effects of the freshwater discharge from a small tide embankment interior in a coastal area in Goheung county were investigated from May to September in 2012. Chemical oxygen demand values (COD) were mostly higher than 2 mg/L in summer ebb tide, which exceed the standard value of water quality criteria II of acceptable level for aquaculture activities. Nitrogen and phosphorus were found as the limiting nutrients for algae growth in summer and fall and in spring, respectively. Nitrogen was the limiting nutrient for diatom growth in the whole studied period. The sudden high values of COD, ammonia, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) were found in water sample collected from station 5 which located in front of the tide embankment sluice gate during spring ebb tide. The freshwater discharge form the tide embankment interior maybe affected the survey areas during a short time interval. Mean values of eutrophication index of the surveyed coastal region in spring, summer and fall were all bigger than 1. Water quality was mostly considered at level II which acceptable for aquaculture activities. Sediment quality in this study was generally in the range of standard for fisheries environment.

• 한국해양학회지
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• 제2권1_2호
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• pp.24-33
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• 1967

본고는 한국연안의 9개검조소 (울릉도, 묵호, 울산, 부산, 진해, 여수, 제주, 목포 및 인천등)의 최근의 월평균해면의 자료를 분석한 성과이다. 평균해면의 변화가 주로 기압 및 바람의 효과, 해수밀도의 변화, 하천유량의 변화 그리고 경도류의 역학적효과등에 기인한다는 것은 여러 해양학자들에 의해 증명되었다. 특히 근래에는 평균해면의 자료를 해황의 변동의 판단에 이용하려고 노력하고 있다. 원래 해양관측은 다액의 경비와 인력을 필요로 하므로 동일해역을 자주 관측한다는 것은 매우 곤란하므로 비교적 용이한 해면의 관측을 통해 해황변동을 파악한다는 것은 매우 흥미있는 사실이라 생각된다. 과거 한국근해의 평균해면에 대한 연구조사는 1930년 소창신길(Ogura,S.)가 원산, 부산, 군산, 인천 및 진남포등의 평균해면의 월편차를 산출발표한것과 금1967년 가을 Listzin, E.가 "도해의 평균해면의 변화"라는 제목의 논문에서 원산 및 부산의 평균해면을 논한 것뿐이다. 그리고 Miyazaki, M.는 1954년 "일본연안의 평균해면의 계절변화"를 연구발표한바 있다. 앞으로 한국연해의 해황판단 에 평균해면자료를 이용시도함에 앞서 우선 평균해면에 미치는 요소를 특히 기압의 영향과 해수밀도의 변화의 효과를 고찰해 보기로 한다.

• 한국농공학회논문집
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• 제49권6호
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• pp.3-9
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• 2007

Stream flow and water quality were measured and analyzed with respect to flow-weighted mean concentrations (FWMCs) of 21 rainfall events from a forested watershed (Forest Research Watershed: FRW) and two mixed watersheds of agriculture and forest (YuPo-Ri Watershed: YPW and WolGog-ri Watershed: WGW) located in the middle of the North Han River basin. The monitoring of each watershed was one year and conducted between 2004 and 2006. YPW showed more intensive agricultural practices than WGW where traditional practices were common. The average of the 21 FWMCs were in the order of YPF>WGW>FRW and were significantly different from each other at the level of 0.05. It was shown that the land use with intensive agricultural practices produced and discharged more NPS pollutants than that with traditional practices and forest. Specially, SS concentrations from the mixed watersheds were significantly higher than those from FRW. Influencing factors on runoff were analyzed rainfall and watershed area. And rainfall intensity was greater impact on runoff than daily rainfall. Measured water quality indices were shown positive correlations among them in general. However, no significant correlation was shown between COD and nutrients(T-N and T-P).

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 추계학술발표회논문집(1)
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• pp.481-486
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• 1997

The interfacial shear stress is experimentally investigated for co-current air-water stratified flow in inclined rectangular channels having a length of 1854mm, width of 120mm and height of 40mm at almost atmospheric pressure. Experiments are carried out in several inclinations from $0^{\circ}\;up\;to\;10^{\circ}$. The local film thickness and the wave height are measured at three locations, i.e., L/H = 8,23, and 40. According to the inclination angle, the experimental data are categorized into two groups; nearly horizontal data group ($0^{\circ}\;{\leq}\;{\theta}\;{\leq}\;0.7^{\circ}$), and inclined channel data group ($0.7^{\circ}\;{\leq}\;{\theta}\;{\leq}\;10^{\circ}$). Experimental observations for nearly horizontal data group show that the flow is not fully developed due to the water level gradient and the hydraulic jump within the channel. For the inclined channel data group, a dimensionless wave height, $\Delta$h/h, is empirically correlated in terms of $Re_{G}$ and h/H. A modified root-mean-square wave height is proposed to consider the effects of the interfacial and wave propagation velocities. It is found that an equivalent roughness has a linear relationship with the modified root-mean-square wave height and its relationship is independent of the inclination.

• 한국동물위생학회지
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• 제20권2호
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• pp.169-175
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• 1997

This study was carried out to assess the effect of the chlorine treatment into water for processing chicken products in each stage of slaughtering, with a special viewpoint related with reducing the viable number of microorganisms by which the water and the chicken body were contaminated. The mean bacterial number on chicken samples after picking process was log5.37$\pm$0.20~5.84$\pm$0.160CFU/$\textrm{cm}^2$. When assessed by standard plate count method, it was the higher one than any other processing stage in which eviscerating, pinning, packaging, and chilling was followed in order of the mean bacterial number. The coliform bacterial numbers on carcasses after sampling from different processing stages were log2.11$\pm$0.63~2.88$\pm$0.25MPN/$\textrm{cm}^2, which show almost similar numbers in each processing stage. But, after chilling process the number was decreased slightly. The bacterial counts in the water for scalding and chilling showed log3.43 $\pm$ 0.59~5.06$\pm$0.21 and log4.30$\pm$0.21~6.62$\pm$0.33CFU/$m\ell$, respectively. In the coliform counts for the water taken out from the 2nd chilling tank, the number was log1.97$\pm$0.35~2.91$\pm$0.22MPN/$m\ell$ which showed higher than those of the 1st and the 3rd chilling tank water. The effect of chlorination in reducing the bacterial numbers was accepted at the residual chlorine concentration of 1$m\ell$/$\ell$by showing the reduction from $10^8$ to $10^4$CFU level and the numbers were decreased less than 10CFU at the concentration of 5mg/$\ell$, when assessed by viable cell counts. In conclusion, these results suggested that chlorination In chilling water with final concentration of 5mg/$\ell$was strongly recommended to reduce the bacterial numbers on final chicken products.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권2호
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• pp.28-36
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• 2012

This study carried out several kinds of investigations such as geology, hydrogeology, groundwater level and quality, surface-water quality, and the quantity and quality of groundwater discharge from the subway to identify the causes of groundwater contamination around the subway tunnel at Suyeong District in Busan City. Geostatistical analyses were also conducted to understand the characteristics of groundwater level and quality distributions. There are Kwanganri Beach and Suyeong River in the study area, which are basically influenced by seawater. The total quantities of groundwater utilization and groundwater discharge from the subway tunnel in Suyeong District are 2,282,000 $m^3$/year, which is 2.4 times larger than the sustainable development yield of groundwater. The lowest groundwater level around the subway tunnel is about 32 m below the mean sea-level. The large drawdown of groundwater led to the inflow of seawater and salinized river water toward the subway tunnel, and therefore the quality of groundwater didn't satisfy the criteria of potable, domestic, agricultural and industrial uses. Distribution maps of groundwater level and qualities produced by kriging were very useful for determining the causes of groundwater contamination in the study area. The distribution maps of electrical conductivity, chloride and sulfate showed the extent of seawater intrusion and the forceful infiltration of the salinized Suyeong River. This study revealed that seawater and salinized river water infiltrated into the inland groundwater and contaminated the groundwater around the subway tunnel, because the groundwater level was seriously drawdowned by groundwater discharge from the subway tunnel. The countermeasure for the minimization of groundwater discharge from the subway tunnel is necessary to prevent the groundwater obstacles such as groundwater depletion, groundwater-quality deterioration, and land subsidence.

• Ecology and Resilient Infrastructure
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• 제6권4호
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• pp.243-249
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• 2019

본 연구는 드론 기반의 초분광 센서를 활용하여 수위변화에 대한 하상재료의 분광정보 차이를 분석하는 것이 목적이다. 하상재료는 흙, 자갈, 호박돌, 갈대, 식생을 대상으로 하였으며 5개 하상재료에 대한 초분광 영상촬영을 실시하고 각 재료의 분광정보를 비교 분석하였다. 수위 변화를 위해 유량조절이 가능한 실험수로를 제작하고 수로 내 하상재료를 설치하였다. 수위 조건은 0.0 m, 0.3 m, 0.6 m이며 수위에 따라 CASE를 구분하였다. 영상촬영 후 각 하상재료별 10개 포인트를 평균한 값을 분석 자료로 사용하였다. 분석 결과 흙, 자갈, 호박돌, 갈대의 파장별 반사율은 비슷한 유형을 보이지만 각 재료별 가시광선과 근적외선 영역에서는 분광정보의 고유특징이 나타났다. 또한 수위가 깊어질수록 가시광선과 근적외선 영역에서 반사율은 감소하고 있으며 감소 비율은 하상재료에 따라 차이가 발생하였다. 하상재료에 대한 고유정보는 향후 하천환경평가를 위한 기초연구 자료로 활용될 것으로 기대된다.

• 한국해안해양공학회지
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• 제7권4호
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• pp.313-320
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• 1995

일정 경사를 갖는 해안에 입사하는 같은 주기의 두개의 파열이 교차하는 경우에 대하여 천해역에서 파랑 변형에 대한 수치해석을 수행하였다. 본 모형은 파랑 에너지 평형 및 파랑운동 보존식에 기초하여, 시간과 수심에 대해 평균한 질량 및 수평방향 운동 보존방정식을 반복적으로 계산하여 해를 구하였다. 계산된 결과를 이용하여, 천해역에서 파열이 교차할 때 파고와 평균수위변동에 영향을 주는 입사 파향각 및 심해파고와 같은 매개변수 변화에 따른 파랑 변형에 대해 고찰하였다.

• 한국산업융합학회 논문집
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• 제21권5호
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• pp.227-234
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• 2018

The smart irrigation system using ICT technology is crucial for stable production of upland crops. The objective of this study was to develop a smart irrigation system that can control soil water, depending on irrigation methods, in order to improve crop production. In surface irrigation, three irrigation methods (sprinkler irrigation (SI), surface drip irrigation (SDI), and fountain irrigation (FI)) were installed on a crop field. The soil water contents were measured at 10, 20, 30, and 40 cm depth, and an automatic irrigation system controls a valve to maintain the soil water content at 10 cm to be 30%. In subsurface drip irrigation (SSDI), the drip lines were installed at a depth of 20 cm. Controlled drainage system (CDS) was managed with two ground water level (30 cm and 60 cm). The seasonal irrigation amounts were 96.4 ton/10a (SDI), 119.5 ton/10a (FI), and 113 ton/10a (SI), respectively. Since SDI system supplied water near the root zone of plants, the water was saved by 23.9% and 17.3%, compared with FI and SI, respectively. In SSDI, the mean soil water content was 38.8%, which was 10.8% higher than the value at the control treatment. In CDS, the water contents were greatly affected by the ground water level; the water contents at the surface zone with 30 cm ground water level was 9.4% higher than the values with 60 cm ground water level. In conclusion, this smart irrigation system can reduce production costs of upland crops.