• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.62-62
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• 2019

본 연구에서는 기상청에서 제공하는 인공위성 관측자료와 레이더 자료를 합성하여 예측된 선행시간 2시간의 강수량 예측자료를 이용하여 도시유역의 침수 발생 여부를 확인할 수 있는 시스템을 개발하였다. 대상유역은 부산광역시에 위치하고 있는 유역면적 $54km^2$의 온천천유역으로, $10m{\times}10m$의 해상도로 지표면의 침수예측을 수행한다. 침수예측에 이용되는 모델은 지표면과 하수관망 사이의 상호작용을 효과적으로 고려할 수 있도록 지표면 2차원, 하수관망 1차원 모델을 연계하였으며, 침수예측에 소요되는 시간을 최소화하기 위하여 OpenMP기반의 병렬해석 기법을 적용하였다. 또한 초기조건에 의한 오차를 줄이기 위하여 하천수위 관측소에 관측된 수위자료를 예측모델의 초기조건으로 입력할 수 있도록 시스템을 구성하였으며 유역 하류단에서 경계조건으로 활용되는 예측수위자료는 시계열자료의 예측에 뛰어난 성능을 보여주는 것으로 알려진 LongShort-term Memory(LSTM) 기법을 적용하여 이용하였다. 본 연구에서 개발된 실시간 도시침수 예측 시스템은 집중호우 발생시 침수 발생 위치를 사전에 빠르게 예측하여 도시유역의 인적 물적 자원의 피해를 저감하는데 적극적으로 활용될 수 있을 것으로 기대된다.

• Journal of Korean Society of Transportation
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• v.22 no.1 s.72
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• pp.43-62
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• 2004

Conventionally the estimation method of the origin-destination Matrix has been developed by implementing the expansion of sampled data obtained from roadside interview and household travel survey. In the survey process, the bigger the sample size is, the higher the level of limitation, due to taking time for an error test for a cost and a time. Estimating the O-D matrix from observed traffic count data has been applied as methods of over-coming this limitation, and a gradient model is known as one of the most popular techniques. However, in case of the gradient model, although it may be capable of minimizing the error between the observed and estimated traffic volumes, a prior O-D matrix structure cannot maintained exactly. That is to say, unwanted changes may be occurred. For this reason, this study adopts a conjugate gradient algorithm to take into account two factors: estimation of the O-D matrix from the conjugate gradient algorithm while reflecting the prior O-D matrix structure maintained. This development of the O-D matrix estimation model is to minimize the error between observed and estimated traffic volumes. This study validates the model using the simple network, and then applies it to a large scale network. There are several findings through the tests. First, as the consequence of consistency, it is apparent that the upper level of this model plays a key role by the internal relationship with lower level. Secondly, as the respect of estimation precision, the estimation error is lied within the tolerance interval. Furthermore, the structure of the estimated O-D matrix has not changed too much, and even still has conserved some attributes.

• Journal of the Korean earth science society
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• v.34 no.6
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• pp.470-478
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• 2013

There have been a number of observed precursors of volcanic activities- such as volcanic earthquake, surface inflation, specific volcanic gas emission, temperature of hot spring- at Mt. Baekdusan since 2002. We identified the increase of the volume of magma chamber beneath Mt. Baekdusan as we observed an inflation trend of vertical and horizontal surface displacement around Cheonji caldera lake by using precise leveling data from 2002 to 2009. The surface displacement trend changed to deflation in 2010, and the trend changed to inflation again after a while. Utilizing the data of inflated surface (46.33 mm) on the northern slope of Mt. Baekdusan from 2002 to 2003, we calculated the volume change of magma chamber beneath the Mt. Baekdusan. The volume change was about 0.008 $km^3$ ($7.7-8.0{\times}10^6m^3$) from 2002 to 2003. It indicated that a new magma (0.008 $km^3$) injected to the magma chamber 5 km below Mt. Baekdusan.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.128-128
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• 2018

하구는 강이 흘러 바다로 유입되는 지역으로 강의 담수와 바다의 염수가 만나는 강의 하류에 형성되며 지형, 담수의 유입, 해수의 조석 등에 의해 염분분포가 변화 하는 특성을 가진다. 또한 하구에 형성되는 하구역은 조수 간만의 차로 인한 상하운동이 일어남으로 인해 염분 농도는 0.5~30 ‰로 매우 광범위하게 나타난다. 하구는 해수가 미치는 최대 경계인 감조역과 해수와 담수가 혼합되는 기수역이 나타나며, 하구에서의 염분의 변화는 동 식물의 생존 및 분포, 수자원 확보 및 관리, 구조물 설치 등 공학적 분야에서도 매우 중요하다. 또한, 염수쐐기와 조석의 영향으로 하구의 수층에서는 담수 및 염분분포가 지점에 따라 다르게 형성이 되기 때문에 하천 수질측정 시 염수에 의해 대표성이 결여될 수 있다. 본 연구는 바다로 유입되는 수영강을 대상으로 염분분포의 특성을 고려하여 중권역 대표지점으로서의 적합성을 판단하고자 하였다. 수영강은 부산 용천산에서 발원하여 회동수원지를 거쳐 온천천과 합류하여 남해로 유입된다. 수영강에 위치한 좌수영교와 수영교에서 조석 간만의 차가 뚜렷하게 나타날 수 있는 대조기와 소조기에 연직 염분분포를 분석하여 하천수질 측정지점의 대표성을 판단하고자 하였다. 만조에서 간조로 수위가 변화 할 때 표층의 담수층이 옅어지는 현상을 보이며 소조기 보다 대조기에서의 담수층 변화 폭이 커지며 수질측정 시 고려하여야 할 것으로 판단된다.

• Journal of the Korean Chemical Society
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• v.56 no.2
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• pp.228-235
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• 2012

A $N_2O_2$ Schiff base ligand, N,N'-bis(4-methoxysalicylidene)phenylendiamine (4-$CH_3O$-salphen) was synthesized. Using the 4-$CH_3O$-salphen, the spectrophoto-metric quantitative analysis of Cu(II) ion in aqueous solution was performed. The optimum condition for the quantitative analysis of Cu(II) ion was determined as the following; the concentration of 4-$CH_3O$-salphen is $2.0{\times}10^{-4}\;mol/L$, ratio between solvent DMSO and water is 50/50(v/v), pH is 5.5. After 1 hr water incubation at $55^{\circ}C$ and then the absorbance measurements at 388 nm, a calibration curve (${\varepsilon}=3.6{\times}10^4\;mol^{-1}cm^{-1}$) with a correlation coefficient ($R^2$=0.9963) was obtained in this condition. Using this optimized condition, the quantitative analysis of Cu(II) ion was performed with various samples such as hot spring water, semiconductor factory waste water and treated water from sewage treatment plant. The average value of the measured values agreed well with standard value with a range of 0.6~5.4%. The limit of determination was 31.77 ng/mL ($5.0{\times}10^{-7}\;mol/L$).

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.463-471
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• 2011

A novel $N_2O_2$ Schiff base ligand, N,N'-bis(4-methoxysalicylidene)phenylendiamine(4-$CH_3O$-Salphen), has been synthesized. It has been revealed that the compound is very useful for the spectrophotometric quantification of Fe(II) and Fe(III) ions in aqueous solutions, such as mineral water, hot spring water, sea water, and waste water. The optimum conditions for the quantitative analysis are the followings; [4-$CH_3O$-Salphen]=$4.0{\times}10^{-4}\;M$, DMF/$H_2O$=70/30(v/v), pH=3.4~3.8, T= at $55^{\circ}C$, and prereaction time=1.0 hr. The sample of single valence state was prepared by the preliminary oxidation or reduction using $H_2O_2$ ($5.0{\times}10^{-4}\;M$) and $NH_2OH{\cdot}HCl$ ($5.0{\times}10^{-4}\;M$). The quantitative analyses of Fe(II) and Fe(III) ion were performed by measuring the absorbance at 434 nm and 456 nm, respectively. The estimated mean values agreed well with the standard values within the range of 2.00~6.90%. The limit of detection was 27.9 ng/mL for Fe(II) and 55.8 ng/mL for Fe(III).

• Microbiology and Biotechnology Letters
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• v.36 no.3
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• pp.182-188
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• 2008

A hyperthermophilic bacteria (strain HJ6) was isolated from a hot springs located in the Arima-cho, Hyogo, Japan. The cells were long-rod type ($2-4{\mu}m$), about $0.4{\mu}m$ in diameter. The pH and temperature for optimal growth were 6.5 and $80^{\circ}C$, respectively. Phylogenetic analysis based on the 16S rDNA sequence and biochemical studies indicated that HJ6 belonged to the genus Thermus thermophilus (Tt). The gene encoding the Trehalose synthase (TS) was cloned and sequenced. The open reading frame (ORF) of the TtTS gene was composed of 2,898 nucleotides and encoded a protein (975 amino acids) with a predicted molecular weight of 110.56 kDa. The deduced amino acid sequence of TtTS showed 99% and 83% identities to the Thermus caldophilus TS and Meiothermus ruber TS, respectively. TtTS gene was expressed in Escherichia coli cells, and the recombinant protein was purified to homogeneity. The optimal temperature and pH for Trehalose synthase activity were found to be $80^{\circ}C$ and 7.5, respectively. The half-life of heat inactivation was about 40 min at $90^{\circ}C$. The maximum trehalose conversion rate of maltose into trehalose by the enzyme increased as the substrate concentration increased, and reached 55.7% at the maltose concentration of 500 mM, implying that the enzyme conversion was dependent of the substrate concentration.

• Journal of Life Science
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• v.23 no.1
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• pp.110-115
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• 2013

A microorganism (strain AR1) producing an extracellular lipolytic enzyme was isolated from hot springs located in Beppu, Japan. Phylogenetic analysis based on the 16S rDNA sequence and biochemical studies indicated that AR1 belongs to the genus Geobacillus. This study focused on novel strategies to increase extracellular lipolytic enzyme production by this novel Geobacillus sp. AR1. Cultures of the AR1 strain grew within a wide temperature range (from 35 to $75^{\circ}C$); the optimum temperature was $65^{\circ}C$. The pH for optimal growth was 6.5, whereas the optimum pH for lipolytic enzyme production was 8.5. The presence of oils in the culture medium led to improvements in lipolytic enzyme activity. Soybean oil was the most efficient inducer, and it yielded better results when added in the exponential phase. On the other hand, the addition of chemical surfactants led to lipolytic enzyme production. Their addition to the culture could affect the location of the enzyme activity. The addition of Tween 20 in the stationary phase significantly increased the proportion of the extracellular enzyme activity. According to the results, following the addition of soybean oil and Tween 20 in the exponential and stationary phases, the extracellular lipolytic activity was increased 2.4-fold compared with that of a control.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.63-63
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• 2019

최근 기후변화로 인한 도시지역 침수 피해를 저감하기 위한 다양한 연구가 수행되고 있으며 침수해석을 위한 기초자료로써 GIS 기반 하수관망 자료 활용의 중요성이 증대되고 있다. 그러나 이러한 하수관망 자료의 대부분은 지자체 수준의 행정단위에 의해 작성/관리 되고 있으며 하수관 망의 유지보수에 중점을 두어 제작되었기 때문에 침수해석을 위한 속성자료가 누락되어 있는 경우가 상당수 존재한다. 따라서 고유의 제작 목적과 침수해석이라는 활용 목적이 일치 하지 않아 속성 데이터 값이 존재하지 않거나 침수 모델링에 필요한 필수 정보가 누락되어 개별 연구자들이 별도의 보완작업을 수행한 후 침수해석에 활용하고 있는 실정이다. 이러한 개인연구자들의 주관적 판단에 의한 하수관망의 단순화 또는 보완작업은 상황에 따라 자료의 불확실성을 증대시키며 연구자의 숙련도와 배경지식에 따라 침수 해석 결과에 많은 영향을 미치고 있다. 따라서 GIS기반 하수관망 자료를 침수 모의에 활용 가능한 입력 자료로 변환 하는 경우 개별 연구자들의 주관적 개입이 최대한 배제된 형태의 자료를 만들기 위한 기본 알고리즘 개발이 시급한 상태이다. 본 연구에서는 서울시 사당역 인근 유역과 부산시 온천천 유역의 GIS 기반 하수관망 자료의 형식에 대해서 알아보고 누락 자료를 보완하기 위한 알고리즘을 개발하였다. 개발된 알고리즘을 활용하여 누락자료가 보완된 하수관망 자료는 향후 개별 연구자들의 주관적 판단을 배제하여 도시침수 해석 시 하수관망 자료의 불확실성을 최소화 하는데 기여할 수 있을 것으로 판단된다.

• The Journal of Engineering Geology
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• v.26 no.4
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• pp.515-529
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• 2016

In this study, geochemical composition, CFCs (Chlorofluorocarbons), ${\delta}^{18}O$, ${\delta}D$, ${\delta}^{13}C$ isotopes and noble gases isotopes (He, Ne) were analyzed to determine their recharge age, source of $CO_2$ gas and noble gases of carbonated hot spring water and carbonated-water samples collected in the Seoqwipo of the Jeju. The pH of the carbonated waters ranges from 6.21 to 6.84, and the high electrical conductivity range ($1,928{\sim}4,720{\mu}S/cm$). Their chemical composition is classified as $Mg(Ca,\;Na)-HCO_3$ and $Na(Ca,\;Mg)-HCO_3$ types. As a result of the calculation of groundwater age using CFCs concentrations as an environmental tracer, the carbonated water and groundwater were estimated to be about 47.5~57.2 years and about 30.3~49.5 years, respectively. The ${\delta}^{13}C$ values of carbonated water range from -1.77 to -7.27‰, and are plotted on thr deep-seated field or the mixing field of the deep-seated and inorganic origin. Noble gases isotopic ($^3He/^4He$, $^4He/^{20}Ne$) ratio shows that helium gas of carbonated hot waters comes from deep-seated magma origin.