• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.32-32
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• 2020

하나의 수계 또는 용수구역 내에서 작물생육기간 동안 지하수자원 수요량의 집중적인 증가로 인해 지역적 지하수 고갈이 발생하여 농작물 피해가 발생하고 있으며 과잉양수로 인한 지하수위 하강으로 사용자간 갈등도 빈번하다. 또한, 기후변화로 인해 극한기후인 가뭄의 잦은 발생은 이러한 현상을 가속화 한다. 지하수 산출성이 좋은 대수층의 공간적 분포는 복잡한 지질구조로 인해 균일하지 않으며 같은 대수층 내에서도 양수 위치에 따라 산출성은 다르게 나타난다. 이러한 지하수 수요와 공급 및 대수층 분포로 인한 지하수자원 불균형의 해소를 위해 지하수가 풍부한 지역에서 부족한 지역으로 지하수를 공급하는 방법을 적용할 수 있다. 이때 기술적용 지역의 지하수 사용 상황 및 공급 가능량을 정량적으로 평가하고 이를 기반으로 지하수 공급을 제어하는 것이 매우 중요하다. 지하수자원의 수요-공급 불균형이 발생할 때 즉각적으로 대응하기 위해서는 실시간으로 지하수 현황을 감시하고 이를 기반으로 공급 가능량을 산정할 필요가 있으며 이는 정보통신기술(Information and Communication Technology, ICT)에 기반한 관정연계관리체계(Well Network System, WNS)를 구성하는 기술 중 하나인 관정군집제어 기술로 구현될 수 있다. 수계 내에 설치된 기존의 양수정과 새롭게 추가된 관측정들을 4G LTE 네트워크를 통해 하나의 관정군으로 묶고 중앙 서버를 통한 자료 분석 및 양수 펌프 제어를 통해 대수층의 공급 능력과 사용자의 수요 현황에 따른 지하수자원의 체계적 분배를 구현하고자 하였다. 관정군집제어는 관정별 지하수위 및 양수정 양수량을 실시간으로 관측하고 이를 분석서버에 전송하여 해당 지하수계의 공급 가능량 및 인접관정 간섭 등을 분석하여 양수정의 펌프를 실시간으로 제어하고 양수된 지하수를 수요 지역으로 이송한다. 본 연구를 통해 관정군집제어 기술의 구현에 필요한 구성요소를 정의하고 이에 대한 구현 방법을 기술하여 WNS를 구성하는 하나의 요소기술 모델로 제시하고자 하였다.

• Geophysics and Geophysical Exploration
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• v.11 no.4
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• pp.302-309
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• 2008

ERT imaging, especially 3-D method, is a very powerful means to obtain a very high resolution image of the subsurface for geotechnical or hydrogeological problems. In this paper, we introduce two examples of successful case histories, where the imaging targets were three-dimensional. First example is the case of 3-D fracture imaging for hydrogeologic application. In this example, the borehole deviation was a critical problem in the ERT imaging and we could obtain real 3-D attitude of fracture system by including the borehole deviation in the inversion. In the second case, we did field experiment to image the empty tunnel with the size of $2m{\times}2m$ and the target was very clearly imaged in 3-D space. In these examples, we could show that 3-D ERT imaging is a very powerful tool for the 3-D subsurface imaging and the method can provide enhanced imaging capabilities especially for the 3-D targets such as fractures and cavities or tunnel.

• Journal of The Korean Association For Science Education
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• v.35 no.1
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• pp.37-52
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• 2015

In this study, assessment items to examine geocognition on plate tectonics were developed and applied to middle and high school students and college students. Conceptual constructs on plate tectonics are Earth interior structure, specific geomorphology, and geologic phenomena at each plate boundary. Construct for geocognition included temporal reasoning, spatial reasoning, retrospective reasoning, and system thinking. Pictorial data in each item were all obtained from GeoMapApp. Students' responses to the items were analyzed and measured cross-sectionally by Rasch model, which distinguishes persons' ability levels based on their scores for all items and compared them with item difficulty. By Rasch model analysis, Wright maps for middle and high school students and college students were obtained and compared with each other. Differential Item Functioning analysis was also implemented to compare students' item responses across school grades. The results showed: 1) Geocognition on plate tectonics was an assessable construct for middle and high school students in current science curriculum, 2) The most distinguished geocognition factor was spatial reasoning based on cross sectional analysis across school grades, 3) Geocognition on plate tectonics could be developed towards more sophisticated level through scaffolding of relevant instruction and earth science content knowledge, and 4) Geocognition was not a general reasoning separated from a task content but a content-specific reasoning related to the content of an assessment item. We proposed several suggestions for learning progressions for plate tectonics and national curriculum development based on the results of the study.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.1
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• pp.31-40
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• 2021

The hydrogen in nominally anhydrous mineral is known to be associated with lattice defects, but it also can exist in the form of water and hydroxyl groups on the large surface of the nanoscale particles. In this study, we investigate the effectiveness of 1H solid-state nuclear magnetic resonance (NMR) spectroscopy as a robust experimental method to quantify the hydrogen atomic environments of amorphous silica nanoparticles with varying relative humidity. Amorphous silica nanoparticles were packed into NMR rotors in a temperature-humidity controlled glove box, then stored in different atmospheric conditions with 25% and 70% relative humidity for 2~10 days until 1H NMR experiments, and a slight difference was observed in 1H NMR spectra. These results indicate that amount of hydrous species in the sample packed in the NMR rotor is rarely changed by the external atmosphere. The amount of hydrogen atom, especially the amount of physisorbed water may vary in the range of ~10% due to the temporal and spatial inhomogeneity of relative humidity in the glove box. The quantitative analysis of 1H NMR spectra shows that the amount of hydrogen atom in amorphous silica nanoparticles linearly increases as the relative humidity increases. These results imply that the sample sealing capability of the NMR rotor is sufficient to preserve the hydrous environments of samples, and is suitable for the quantitative measurement of water content of ultrafine nominally anhydrous minerals depending on the atmospheric relative humidity. We expect that 1H solid-state NMR method is suitable to investigate systematically the effect of surface area and crystallinity on the water content of diverse nano-sized nominally anhydrous minerals with varying relative humidity.

• Journal of Environmental Policy
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• v.12 no.3
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• pp.21-47
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• 2013

The aim is to analysis landslide vulnerability in Inje, Korea, using GCI(Geospatial Correlative Integration) and probability rainfalls based on geographic information system (GIS). In order to achieve this goal, identified indicators influencing landslides based on literature review. We include indicators of exposure to climate(rainfall probability), sensitivity(slope, aspect, curvature, geology, topography, soil drainage, soil material, soil thickness and soil texture) and adaptive capacity(timber diameter, timber type, timber density and timber age). All data were collected, processed, and compiled in a spatial database using GIS. Karisan-ri that had experienced 470 landslides by Typhoon Ewinia in 2006 was selected for analysis and verification. The 50% of landslide data were randomly selected to use as training data, while the other 50% being used for verification. The probability of landslides for target years (1 year, 3 years, 10 years, 50 years, and 100 years) was calculated assuming that landslides are triggered by 3-day cumulative rainfalls of 449 mm. Results show that number of slope has comparatively strong influence on landslide damage. And inclination of $25{\sim}30^{\circ}C$, the highest correlation landslide. Improved previous landslide vulnerability methodology by adopting GCI. Also, vulnerability map provides meaningful information for decision makers regarding priority areas for implementing landslide mitigation policies.