• 환경영향평가
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• 제17권3호
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• pp.201-211
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• 2008

According to IPCC fourth assessment report in 2007, global mean temperatures have risen by 0.74 degrees Celsius over the past 100 years. Moreover, in the recent 25 years, global mean temperatures have risen by 0.45 degrees Celsius, which is 2.4-times larger than those in the past 100 years. The evidences for climate change, such as sea level rise, arctic glacier melt, and desertification in Asia, have occurred and increased over the globe. In Korea, because regional climate has been changed, types of agriculture and fishery should be replaced. And as precipitation pattern behave differently from the past decades, water management would be more difficult, furthermore, atmospheric environment, related to concentrations for ozone, sulfate, etc., could be worse. Nevertheless, we have only focused on greenhouse gas reduction duty for the Convention of Climate Change. Fortunately, in the fourth plan on climate change, we have planned to manage climate change more actively since 2007. In Korea, the emission of carbon dioxide has increased about 1.9-times more, from 311million ton in 1990 to 591million ton in 2004. And also about 2 ppm rise every year for concentrations of carbon dioxide in the atmosphere. As a result, ecosystem, quality of water and atmosphere would be affected. Here, the emission of greenhouse gases over the globe is examined, and the effect of greenhouse gases for climate change is reviewed from the results of previous studies. In addition, the countermeasures of mitigation and adaptation on climate change were discussed for the understanding.

• 분석과학
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• 제10권5호
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• pp.332-342
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• 1997

15종의 휘발성 유기오염물질을 blank water에 $20{\mu}g/L$의 농도로 첨가하여 Purge and Trap과 Gas Chromatograph/Mass Spectrometer(GC/MS)로 분석하였다. 그 결과 100%의 총평균 회수율과 3.6%의 평균상대표준편차를 얻었으며, 검출한계는 $1.9{\sim}3.3{\mu}g/L$를 나타내어 분석법이 적합함을 알 수 있었다. 반월염색단지 공동폐수처리장의 폐수를 분석한 결과 15종의 유기물이 검출되었으며, 이 중 미국 EPA에서 규제하는 priority pollutant는 trichloroethylene, tetrachloroethylene, toluene, ethylbenzene 등 4종이었다. 한편, 환경부가 폐수 중에서 규제하는 trichloroethylene과 tetrachloroethylene의 농도는 각각 34.6과 $75.6{\mu}g/L$로 배출허용기준 이하로 검출되었다.

• 한국수자원학회논문집
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• 제45권8호
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• pp.805-814
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• 2012

대부분의 수문자료는 지상관측을 통해 얻어진다. 그러나 어떤 지역은 접근이 어렵거나 장기적인 관측에 어려움이 있기 때문에 지상관측을 대체하거나 보완할 새로운 방법이 요구된다. 시 공간적 한계를 극복할 수 있는 대안으로 미항공우주국 NASA에서 2002년 지구 중력장을 측정하는 GRACE(Gravity Recovery And Climate Experiment) 인공위성 자료가 존재한다. 본 연구에서는 GRACE Level-2 중력자료를 이용하여 공간평활화 반경별(0 km, 300 km, 500 km)로 한반도의 수자원변화량(GRACE-based TWSC)을 산정하였다. 산정된 결과의 타당성을 검증하기 위해, 지상 수문 관측자료를 이용한 수자원 변화량(land-based TWSC)과의 비교를 시도하였다. Land-based TWSC는 WAMIS의 강우량, 증발 산량 및 GLDAS의 유출량 자료를 이용해 계산하였다. GRACE-based TWSC와 land-based TWSC의 RMSE 검정 결과, 공간평활화 반경 500 km의 위성자료가 한반도에 가장 적합한 것으로 나타났다. 한반도의 월별 평균 TWSC는 0.986 cm/month로 나타났고, 이러한 큰 변화폭 때문에 안정적수자원 확보를 위한 대처 방안의 마련이 필요한 것으로 평가된다.

• Nuclear Engineering and Technology
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• 제52권12호
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• pp.2709-2716
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• 2020

Compositions of large nuclear cores (e.g. boiling water reactors) are highly heterogeneous in terms of fuel composition, control rod insertions and flow regimes. For this reason, they usually lack high order of symmetry (e.g. 1/4, 1/8) making it difficult to estimate their neutronic parameters for large spaces of possible loading patterns. A detailed hyperparameter optimization technique (a combination of manual and Gaussian process search) is used to train and optimize deep neural networks for the prediction of three neutronic parameters for the Ringhals-1 BWR unit: power peaking factors (PPF), control rod bank level, and cycle length. Simulation data is generated based on half-symmetry using PARCS core simulator by shuffling a total of 196 assemblies. The results demonstrate a promising performance by the deep networks as acceptable mean absolute error values are found for the global maximum PPF (~0.2) and for the radially and axially averaged PPF (~0.05). The mean difference between targets and predictions for the control rod level is about 5% insertion depth. Lastly, cycle length labels are predicted with 82% accuracy. The results also demonstrate that 10,000 samples are adequate to capture about 80% of the high-dimensional space, with minor improvements found for larger number of samples. The promising findings of this work prove the ability of deep neural networks to resolve high dimensionality issues of large cores in the nuclear area.

• 한국수자원학회논문집
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• 제33권3호
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• pp.307-314
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• 2000

본 연구에서는 조선시대부터 최근까지의 약 200년간의 서울지점 연강수량 자료를 이용하여 다우해 및 과우해의 재현특성에 대해서 살펴보았다. 기본적으로 원자료에 나타난 자기상관특성을 분석함은 물론 몇 개의 절단수준(truncation level)에 대해 다우해 및 과우해의 재현경향이 어떤지를 살펴보았다. 또한 각각의 절단수준에 대해 연강수량을 평년, 다우해 및 과우해로 나누고 각각의 전이확률을 조사하여 봄으로서 궁극적으로는 각각의 경우에 대해 평년, 다우해 및 과우해의 평균재해기간이 얼마나 되는지를 추정해 보았다. 이러한 분석은 조선시대의 측우기기록과 근대의 강우관측기록을 포함한 전체의 기록뿐만 아니라 측우기 관측기록 및 근대 관측기록에 대해 각각 적용해 봄으로서 비교 분석될 수 있도록 하였다. 전체자료를 이용한 결과의 경우 1900년 전후의 건조기의 영향을 제외한다면 건조기의 전반부 및 후반부만을 이용한 결과와 어느 정도 유사한 결과를 줌을 알 수 있었다. 아울러 건조기의 전반부와 후반부에 대한 비교에서는 건조기 후반부의 기록에서, 특히 상대적으로 큰 절단수준에 대해, 과우해의 재현기간이 상대적으로 크게 나타나는 차이를 살펴볼 수 있었다. 대략 평균에서 표준편차(약370mm)정도가 벗어난 수준을 다우해 및 과우해의 기준으로 본다면 다우해의 재현기간은 5∼6년, 과우해의 재현기간은 6∼7년 정도로 과우해의 재현기간이 다우해의 재현기간 보다 약간 길게 나타나고 있음을 알 수 있었다.

• 한국보건간호학회지
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• 제12권2호
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• pp.185-200
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• 1998

It has been contributed to public health that the hospital has multiplied in the aspect of number and has been a large size with development of modern medical science, meanwhile the problem of hospital infection is coming out seriously. Respiratory hospital infection among hospital infections develops, very commonly from patients having taken the operation of intubation or tracheostomy, which results from a big factor that the infection developed from medical appliances used for respiration aids, contamination of solution and infection of medical staff. This study is separated into four steps-the time to use normal saline and distillation water for storaging catheter which are the cause of the infection of solution to store distillation water and catheter, not to say the catheter used when the patient who should get tracheostomy operation takes suction. The purpose of this study is to offer the basic data which are needed to check contamination degree as time goes by and nurse intervention and grope for a new nursing intervention. The target of this study is hospitalized 1D an intensive care unit having 700 sickbeds which is located in IKSAN city and it targeted patients before 7 days passed after an operaion of a tracheostormy. Materials collected were analyzed by SPSS PC+ figures program. The result of this study were as follows ; 1. The gradual contamination levels of the normal saline used In suction are showing that colony increase in proportion to the length of time. 2. while colony increases in normal saline with the lapse of time. distillation water mixed with 5cc of potadine did not show any sign of the formation of colony from its preparation until it was used for 8 hours. 3. Such variables as the period of intubation insertion. the length of hospitalization in I.C.U. the age and the level of contamination of normal saline have no inter-relationship. Therefore. as the length of normal saline used In suction. the contamination level increases with the excelleration of the contamination speed. 4. Regarding the number of suction and the contamination level of the normal saline. We can observe correlation contamination level in the 3 step of suction(mean value:13.4) and the saline which was used for one hours(r=0.702. P=0.00l). four hours(r=0.694. P=0.00l). eight hours(r=0.488. P=0.029). Further we can observe contamination in the 4 step of suction (mean value: 17 .8) well as saline used for eight hours; [for one hours (r=0.64l. P=0.002). four hours (r=0.670. P=0.00l). eight hours (r=0.57 4. P=0.008)]. Thesedays clinics use normal saline by changing it. three times a day. however. the timing of saline change and the current suction methoed should be changed given the one hour used normal saline contamination number 79.850. Regarding the number of suction and the contamination lend of the normal saline.

• 한국물환경학회지
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• 제28권2호
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• pp.202-212
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• 2012

Due to the deterioration of water supply network and the deficiency of raw water, the water utility of local governments have performed various projects to improve their revenue water ratio. However, it is very difficult to estimate the cost for maintaining the revenue water ratio at higher level after completing the project, because local governments have different conditions affecting the operating and maintenance cost of water supply network. The purpose of this study is to present a procedure to estimate the operating and maintenance cost required to maintain the target revenue water ratio of the water supply network. For this purpose, we estimated the cost used only for operation and maintenance of water supply network of 164 local governments with the aid of K-Mean Clustering Analysis and the data from 40 representative local governments. Then, the regression analysis was performed to find relationship between revenue water ratio and the operating and maintenance cost with two different data sets generated by two classification methods; the first method classifies the local governments by means of k-means clustering, and the other classifies the local governments according to the index standardized by the operating and maintenance cost per unit length of water mains per revenue water ratio. The results shows that the method based on the index standardized by the cost and revenue water ratio of each government produces more reliable results for finding regression equations between revenue water ratio and the operating and maintenance cost only for water supply network. The estimated regression equations for each group can be used to estimate the cost required to keep the target revenue water ratio of the local government.

• 대한토목학회논문집
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• 제35권3호
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• pp.579-588
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• 2015

최근 기후변화로 인해 강우강도와 홍수 발생빈도가 증가하고 있으며 여름철 태풍으로 인한 침수피해의 가능성이 높아지고 있다. 대하천 사업 이후 하천의 홍수터를 활용하여 생태공원이나 체육시설 등과 같은 다양한 친수시설들이 조성되었으나 태풍으로 인한 하천의 홍수위 상승은 이와 같은 친수시설들에 대한 직접적인 침수피해를 야기할 수 있다. 이러한 홍수터 친수시설에 대한 수리학적 영향 분석이나 안정성 평가를 위해서는 수치해석이 선행되어야 하며, 수위의 상승 및 하강에 의해 발생하는 마름/젖음 현상에 대한 처리가 매우 중요하다. 본 연구에서는 마름/젖음 해석이 가능한 Nays2D 모형을 이용하여 마름/젖음이 발생하는 단순 지형에 대한 적용성을 분석하고, 마름이 발생하는 자연하천에 적용하였다. 실제 태풍 사상에 대한 모형의 현장 적용결과를 수위관측소에서 실측된 실측수위와 비교했으며, 그 결과 $R^2$, AME, RMSE 값이 각각 0.988, 0.208, 0.239로 통계적으로 높은 상관관계를 보였다. 또한, 모형의 결과를 이용하여 홍수위험도 지수를 산정하였으며, 연구결과를 통해 홍수터 친수시설 홍수위험도 평가를 실시하였다.

• Fisheries and Aquatic Sciences
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• 제1권2호
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• pp.192-200
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• 1998

This study was carried out to evaluate the effect of feeding higher protein feeds with lesser amount, but feeding the constant total protein input for all treatments, on water quality and nitrite toxicity in channel catfish ponds. There was no significant difference in survival rate among treatments $(P>0.05)$. Specific growth rate (SGR) for Treatment 1$(28\%\;protein\;and\;100\%\;of\;satiation)$ was significantly higher $(P>0.05)$ than for Treatment 3$(36\%\;protein\;and\;87.5\%\;of\;satiation)$, but not significantly higher than for Treatment 2 $(32\%\;protein\;and\;77.8\%\;of\;satiation)$ at constant digestible energy (DE), 3.08kcal/g (treatments 1, 2 and 3). At constant DE/P (treatments 4, 2 and 5), no significant difference in SGR was observed among treatments. Feed conversion ratio (FCR) slightly improved or improved as dietary protein level increased from $28\%$ to $32\%$ and feed allowance decreased by $12.5\%$, but did not improve as dietary protein level increased from $32\%$ to $36\%$ and feed allowance decreased by $22.2\%$, at constant DE and constant DE/P. There was no significant difference in water quality variables, such as total ammonia nitrogen (TAN), nitrite, chlorophyll a, soluble phosphorous concentrations among treatments, but significant difference in water quality variables over time as amount of feed fed increased $(P<0.0001)$. There was a trend toward increase in TAN and nitrite over time. A strong linear regression was observed between mean total ammonia nitrogen and nitrite for all treatments Y (Nitrite) =$0.04\times (TAN)+0.01$, $R_2=0.89$. Methemoglobin percent in the blood of catifish was not significantly different among treatments. And its mean value was $7.5\%$, which was relatively low, so that it was not serious problem in catfish production pond under these experiment conditions. There was the stronger linear regression between the percentage of Methemoglobin and the molar ratio of nitrite to chloride rather than nitrite alone: $Y\;(Methemoglobin\;\%)\;=\;58.45\;\times\;(NO^{2-}/Cl^-)\;+\;0.41,\;R^2=0.60$. These results indicate that deterioration of water quality has no strong impact on poor weight gain for $36\%$ dietary protein in this study.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1099-1104
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• 2008

Recent year, mean energy consumptions of a people are higher than other country. And international oil price became over 120 dollar. This energy environment as well as energy war. Maybe, the Meteorological Administration is going to enforce scorching heatwave special report system from that come summer. Besides, 2008 summer, maximum demand power is expected by 64,240,000kW. The electric power equipment reserve rate appeared in to keep 12.5% level. Chilled water storage system witch is one of electric load administration system. Heat pump system used cooling tower heat recovery is advantage that use is possible to summer in small a public bath building. In this paper, we suggest that heat pump system by heat recovery using cooling tower when it is heating operation of ambient air temperature. To apply cooling tower heat recovery heat pump to chilled water heat storage type and achieved performance evaluation about operation. As a result, performance of heat pump system that about 121% in cooling mode, 138% in heating mode higher than KEPCO standard. And heating operation possible to ambient air temperature about $23^{\circ}C$, which of appear cooling tower outlet temperature about $13^{\circ}C$.