• 한국지하수토양환경학회지:지하수토양환경
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• 제17권3호
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• pp.59-75
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• 2012

It is getting difficult to manage water resources in South Korea because more than half of annual precipitation is concentrated in the summer season and its intensity is getting severe due to global warming and climate change. Artificial recharge schemes can be a useful method to manage water resources in Korea adapting to climate change. Patent analysis enables us to prevent overlapping investment and to find out unoccupied technology. In this study, international patent trends and barriers of artificial recharge technology are analysed for patents of Korea, Japan, the United States and Europe. The four artificial recharge methods such as well recharge, surface infiltration, bank filtration and underground structures are classified as main class and the nine sub-technologies such as water intake, water treatment, injection wells, monitoring of groundwater flow, groundwater pumping, surface infiltration/soil aquifer treatment, radial collection well, iron/manganese treatment, and underground subsurface dam are classified as intermediate class. Water intake techniques are subdivided into five classifications. Total 1,281 of patents, searched by WIPS DB tool and selected after removing noisy patents, are analyzed quantitatively to evaluate application trends by year, applicant, country for each classified technologies and analyzed qualitatively to find out occupied and unoccupied technologies. It is expected that upcoming research and development project could be performed efficiently in that an avoidance plan for the similar patents and differentiation plan for the advancing patents are set up based on the quantitative and qualitative analysis results from this research.

• 한국환경과학회지
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• 제28권9호
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• pp.737-749
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• 2019

In this study, the sensitivity analysis of hydraulic conductivity and separation distance (distance between injection well and pumping well) was analyzed by establishing a conceptual model considering the hydrogeologic characteristics of facility agricultural complex in Korea. In the conceptual model, natural characteristics (topography and geology, precipitation, hydraulic conductivity, etc.) and artificial characteristics (separation distance from injection well to pumping well, injection rate and pumping rate, etc.) is entered, and sensitivity analysis was performed 12 scenarios using a combination of hydraulic conductivity ($10^{-1}cm/sec$, $10^{-2}cm/sec$, $10^{-3}cm/sec$, $10^{-4}cm/sec$) and separation distance (10 m, 50 m, 100 m). Groundwater drawdown at the monitoring well was increased as the hydraulic conductivity decreased and the separation distance increased. From the regression analysis of groundwater drawdown as a hydraulic conductivity at the same separation distance, it was found that the groundwater level fluctuation of artificial recharge aquifer was dominantly influenced by hydraulic conductivity. In the condition that the hydraulic conductivity of artificial recharge aquifer was $10^{-2}cm/sec$ or more, the radius of influence of groundwater level was within 20 m, but In the condition that the hydraulic conductivity is $10^{-3}cm/sec$ or less, it is confirmed that the radius of influence of groundwater increases sharply as the separation distance increases.

• 한국지구과학회지
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• 제41권2호
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• pp.129-136
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• 2020

가뭄은 일반적으로 장기간에 걸쳐 물 공급이 부족하여 나타나는 환경 재앙 중 하나로 대부분 넓은 지역에 걸쳐 나타난다. 원격탐사 자료는 이러한 넓은 지역에서 나타나는 가뭄 모니터링에 적합한 방법이다. 따라서 이 연구에서는 강원도 소양호 지역의 Landsat 위성 영상 자료를 활용하여 약 30년(1985-2015) 동안의 소양호 면적을 산출하고 이를 가뭄 패턴과 분석하였다. 특히 ISODATA, Maximum likelihood 및 인공신경망을 활용하여 Landsat 영상을 분류하여 소양호 면적을 산출하였다. 또한 가뭄 패턴을 분석하기 위하여 산출된 호수 면적과 소양호 지역의 강수량을 활용한 표준강수지수(Standardized Precipitation Index: SPI)와의 상관관계를 분석하였다. 영상 분류 연구 결과, ISODATA, Maximum likelihood 및 인공신경망 방법 중에서 호수 면적 산출의 최적의 방법은 인공신경망 방법임을 알 수 있었다. 또한, 인공신경망 방법을 적용하여 산출한 호수 면적과 SPI와의 상관관계 분석 결과 R² 값이 0.52를 가진다. 즉, SPI지수가 낮을 때 호수 면적이 감소하는 것을 알 수 있었다. 즉 호수 면적 변화를 통하여 소양호 지역의 가뭄 상태 감지 및 모니터링이 가능하다는 것을 알 수 있었다. 이 연구는 향후 지역 가뭄 모니터링 프로그램 개발 등에 사용이 가능할 것이다.

• 한국지구과학회지
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• 제29권5호
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• pp.396-407
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• 2008

Hydrogeologic properties of a well field around middle mountainous areas in Pyosun, Jeju volcanic island were examined based on water level monitoring, geologic logging and pumping test data. Due to the alternating basaltic layers with varying permeability in the subsurface, it is difficult to analyze the hydraulic responses to artificial pumping and/or natural precipitation. The least permeable layer, detrital materials with clay, is found at a depth of 200 m below surface, but it is not an upper confining bed for lower main aquifer. Nevertheless, this layer may serve as a natural barrier to vertical percolation and to contaminant migration. Water levels of the production wells are dominantly affected by pumping frequently, while those of the remote observation wells are controlled by ambient precipitation. Results of pumping tests revealed a possible existence of horizontal anisotropy of transmissivity. However, some results of this study include inherent limitations enforced by field conditions such as the consistent of groundwater production and the set of time periods for the cessation of the pumping prior to pumping tests.

• Advances in environmental research
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• 제4권2호
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• pp.119-133
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• 2015

Water pollution means that the physical, chemical and biological properties of water are changing. In this study, adsorption was chosen as the treatment method because it is an eco-friendly and low cost approach. Magnetite is a magnetic material that can synthesize chemical precipitation. Magnetite was used for the removal of copper in artificial water samples. For this purpose, metal removal from water dependent on the pH, initial concentration of metal, amount of adsorbent and effect of sorption time were investigated. Magnetite was characterized using XRD, SEM and particle size distribution. The copper ions were determined by atomic absorption spectrometry. The adsorption of copper on the magnetite was studied in a batch process, with different aqueous solutions of Cu (II) at concentrations ranging from 10 to $50mg\;l^{-1}$. Optimum conditions for using magnetite were found to be concentration of $10mg\;L^{-1}$, pH: 4.5, contact time: 40 min. Optimum adsorbent was found to be 0.3 gr. Furthermore, adsorption isotherm data were analyzed using the Langmuir and Freundlich equations. The adsorption data fitted well with the Freundlich ($r^2=0.9701$) and Langmuir isotherm ($r^2=0.9711$) equations. Kinetic and equilibrium aspects of the adsorption process were studied. The time-dependent Cu (II) adsorption data were described well by a pseudo-second-order kinetic model.

• 생태와환경
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• 제42권2호
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• pp.221-231
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• 2009

This study was carried out to comparatively identify characteristics of turbid water influence in Imha Reservoir, Soyang Reservoir, and Daecheong Reservoir in Korea. We used 3 years dataset from 2002 to 2004 and analyzed seasonal water quality characteristics, particular parameters in association with turbidity, and light transparency to figure out the trends. All parameters to be used in the study were total phosphate (TP), total nitrogen (TN), chlorophyll-${\alpha}$ (Chl), suspended solids (SS), Secchi depth (SD), conductivity, and verticallight extinction coefficienct($K_d$), euphotic zone ($Z_{eu}$), and critical depth ($Z_p$). All parameters depend on season and watershed. Suspended solids from Soyang Reservoir were usually caused by TP, mainly related to living wastes and agricultures in upper stream. Daecheong Reservoir was influenced by organic matters related to large phytoplankton biomass in summer and inorganic suspended solids by nutrients in the winter. However, in case of Imha Reservoir, turbid water, consisted in silt and clay through heavy precipitation remained in the waterbody to decrease water transparency along with TP and caused the light limitation in winter. Overall results suggest that it was necessary to establish various management programs because the reasons occurring turbidity were varied according to the reservoir circumstances.

• 한국물환경학회지
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• 제23권3호
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• pp.339-347
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• 2007

Zooplankton community dynamics were studied after establishment of an artificial vegetation island (AVI) in Lake Paldang, from April 2005 to November 2006. There were distinct seasonal and inter-annual changes of total zooplankton abundance at the survey site. Total zooplankton abundance rapidly increased in spring and fall, while it remained low throughout winter. During summer, the dynamics of zooplankton community seemed to be largely affected by hydrological parameters such as, precipitation and inflow. Total zooplankton abundance and biomass below AVI was much higher than that of pelagic zone (L1) in Lake Paldang. Copepoda and cladocera represented the main bulk of the zooplankton community from summer to fall at the both sites. Copepods were more dominant at AVI area, while cladocera were more dominant at pelagic zone (L1). Water quality, prey and habitat condition, species competition between zooplankton seemed to play important roles in dominance of the copepoda and cladocera in zooplankton community at AVI area. Our results conclude that artificial vegetation island provide the stable habitat and besides phytoplankton, diverse food to zooplankton, and consequently influence the diversity and richness of zooplankton community.

• 대한지리학회지
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• 제46권3호
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• pp.319-330
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• 2011

본 연구에서는 지상관측 토양수분, 강수량, 지면온도 및 MODIS NDVI와 인공신경망모형을 이용하여 토양수분 공간분포 산정 모형을 제안하였으며, 신뢰성 높은 토양수분 관측 자료를 보유한 용담댐 유역에 대하여 모형의 적용성을 검증하였다. 토양수분 산정모형의 학습에 사용된 주천, 부귀, 상전의 3개 지점의 경우 약 0.9353의 상관계수와 약 1.4957%의 평균제곱근오차를 보여주며, 검증지점으로 사용된 천천2의 경우에는 약 0.8215의 상관계수와 약 4.2077%의 평균제곱근오차를 보여 토양수분 산정모형의 적용가능성이 높다고 판단된다. 인공위성으로부터 관측된 광역의 식생정보와 자료간의 비선형 상관특성을 잘 구현하는 인공신경망을 활용하여 수립된 토양수분 산정모형을 이용하여 용담댐 유역의 토양수분 공간분포도를 산정한 결과, 용담댐 유역의 대부분을 차지하고 있는 산림지역의 토양수분이 다른 지역에 비하여 높은 수치를 보여주는 토양수분의 분포를 보여주었다. 본 연구를 통해 제시된 토양수분 산정 방법은 광역 토양수분 산정에 유용한 접근법으로 판단된다.

• Journal of Microbiology and Biotechnology
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• 제22권11호
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• pp.1568-1574
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• 2012

Microbiological calcium carbonate precipitation (MCCP) has been investigated for its ability to improve the durability of cement mortar. However, very few strains have been applied to crack remediation and strengthening of cementitious materials. In this study, we report the biodeposition of Bacillus subtilis 168 and its ability to enhance the durability of cement material. B. subtilis 168 was applied to the surface of cement specimens. The results showed a new layer of deposited organic-inorganic composites on the surface of the cement paste. In addition, the water permeability of the cement paste treated with B. subtilis 168 was lower than that of non-treated specimens. Furthermore, artificial cracks in the cement paste were completely remediated by the biodeposition of B. subtilis 168. The compressive strength of cement mortar treated with B. subtilis 168 increased by about 19.5% when compared with samples completed with only B4 medium. Taken together, these findings suggest that the biodeposition of B. subtilis 168 could be used as a sealing and coating agent to improve the strength and water resistance of concrete. This is the first paper to report the application of Bacillus subtilis 168 for its ability to improve the durability of cement mortar through calcium carbonate precipitation.

• 한국수자원학회논문집
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• 제56권11호
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• pp.801-813
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• 2023

최근 인공신경망(Artificial Neural Network, ANN)의 연구가 활발하게 진행되면서 ANN을 이용하여 하천의 수질을 예측하는 연구가 진행되고 있다. 그러나 ANN은 Black-box의 형태이기 때문에 ANN 내부의 연산과정을 분석하는데 어려움이 있다. ANN의 연산과정을 분석하기 위해 설명가능한 인공지능(eXplainable Artificial Intelligence, XAI) 기술이 사용되고 있으나, 수자원 분야에서 XAI 기술을 활용한 연구는 미비한 실정이다. 본 연구는 XAI 기술 중 Layer-wise Relevance Propagation (LRP)을 사용하여 낙동강의 다산 수질관측소의 수온, 용존산소량, 수소이온농도 및 엽록소-a를 예측하기 위한 Multi Layer Perceptron (MLP)을 분석하였다. LRP를 기반으로 수질을 학습한 MLP를 분석하여 수질을 예측하기 위한 최적의 입력자료를 선정하고, 최적의 입력자료를 이용하여 학습한 MLP의 예측결과에 대한 분석을 실시하였다. LRP를 이용하여 최적의 입력자료를 선정한 결과를 보면, 수온, 용존산소량, 수소이온농도 및 엽록소-a 모두 주변지역의 일 강수량을 제외한 입력자료를 학습한 MLP의 예측정확도가 가장 높았다. MLP의 용존산소량 예측결과에 대한 분석결과를 보면, 최고점에서 수소이온농도 및 용존산소량의 영향이 크고 최저점에서는 수온의 영향이 큰 것으로 분석되었다.