• Earthquakes and Structures
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• 제13권6호
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• pp.573-588
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• 2017

The earthquake input is required when the soil-structure interaction (SSI) analysis is performed by the direct finite element method. In this paper, the earthquake is considered as the obliquely incident plane body wave arising from the truncated linearly elastic layered half space. An earthquake input method is developed for the time-domain three-dimensional SSI analysis. It consists of a new site response analysis method for free field and the viscous-spring artificial boundary condition for scattered field. The proposed earthquake input method can be implemented in the process of building finite element model of commercial software. It can result in the highly accurate solution by using a relatively small SSI model. The initial condition is considered for the nonlinear SSI analysis. The Daikai subway station is analyzed as an example. The effectiveness of the proposed earthquake input method is verified. The effect of the obliquely incident earthquake is studied.

• 한국환경복원기술학회지
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• 제12권3호
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• pp.106-115
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• 2009

Knowledge about how to stabilize soil structure is essential to conserve soil systems and maintain various biogeochemical processes through soil. In urban area, soil structural systems are degraded with inappropriate management and land use and become vulnerable to erosion. We analyzed the structural changes of surface soils with different land uses, i.e., forests, parks, roadside green area, riparian area, and farmlands (soybean fields), in the Anyang Stream Watershed in order to find the factors influencing the stability of soil structure and the implication for better management of surface soil. Soil organic matter contents of other land use soils were only 18~52% of that in forest soils. Soil organic matter increased the stability of soil aggregates in the order of soybean fields < roadsides < riparian < parks < forests and also reduced soil bulk density (increased porosity). The lowest stability of soybean field soils was attributed to the often disturbance like tillage and it was considered that higher stability of park soils comparing to other land use soils except forests was owing to the covering of soil surface with grass. These results suggest that supply of soil organic matter and protection of soil surface with covering materials are very important to increase porosity and stability of soil structure.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 INTERNATIONAL SYMPOSIUM ON SOIL & GROUNDWATER ENVIRONMENT
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• pp.242-243
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• 2005

• Geomechanics and Engineering
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• 제13권6호
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• pp.893-906
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• 2017

Automatic large scale soil model generation is very critical stage for earthquake hazard simulation of urban areas. Manual model development may cause some data losses and may not be effective when there are too many data from different soil observations in a wide area. Geographic information systems (GIS) for storing and analyzing spatial data help scientists to generate better models automatically. Although the original soil observations were limited to soil profile data, the recent developments in mapping technology, interpolation methods, and remote sensing have provided advanced soil model developments. Together with advanced computational technology, it is possible to handle much larger volumes of data. The scientists may solve difficult problems of describing the spatial variation of soil. In this study, an algorithm is proposed for automatic three dimensional soil and velocity model development of southern part of the European side of Istanbul next to Sea of Marmara based on GIS data. In the proposed algorithm, firstly bedrock surface is generated from integration of geological and geophysical measurements. Then, layer surface contacts are integrated with data gathered in vertical borings, and interpolations are interpreted on sections between the borings automatically. Three dimensional underground geology model is prepared using boring data, geologic cross sections and formation base contours drawn in the light of these data. During the preparation of the model, classification studies are made based on formation models. Then, 3D velocity models are developed by using geophysical measurements such as refraction-microtremor, array microtremor and PS logging. The soil and velocity models are integrated and final soil model is obtained. All stages of this algorithm are carried out automatically in the selected urban area. The system directly reads the GIS soil data in the selected part of urban area and 3D soil model is automatically developed for large scale earthquake hazard simulation studies.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 INTERNATIONAL SYMPOSIUM ON SOIL & GROUNDWATER ENVIRONMENT
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• pp.172-173
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• 2005

• Environmental Analysis Health and Toxicology
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• 제24권3호
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• pp.251-259
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• 2009

This study was conducted to measure the concentration of PCBs in pine needles and soil in urban (Seoul, many artificial sources of PCBs), semi-rural (Anseong, small town located below Seoul in wind direction) and rural areas (Jincheon, rarely artificial sources of PCBs) in which the artificial production amount of PCBs are different. The total PCBs concentrations in pine needles, which did not show big difference in three sampling sites, were 107.5 pg/g (urban), 94.8 pg/g (semi-rural) and 78.8 pg/g (rural) respectively. The low chlorinated PCBs were major component in pine needles and the PCBs congener concentration profile of each sampling area were similar each other, and the octanol-air partitioning coefficient, Koa, highly correlated with the PCBs concentrations in pine needles. The total PCBs concentrations in soil which did show big difference in three sampling sites, were 830.0 pg/g (urban), 314.1 pg/g (semi-rural) and 136.5 pg/g (rural) respectively. The high chlorinated PCBs were major component in soil and the PCBs congener concentration profile of each sampling area were similar each other. There was no similarity between the PCBs concentration of pine needles and those of soil at each site, because of the different mechanism of deposition and volatilization processes of PCBs. The total PCBs concentrations of 2009 became 12.9 times lower than those of 2001. The reduce rate of PCB 28 was the greatest.

• 한국농공학회논문집
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• 제61권5호
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• pp.89-99
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• 2019

In this study, we estimated the spatially-distributed soil moisture at the high resolution ($10m{\times}10m$) using the satellite-based Sentinel-1A/B SAR (Synthetic Aperture Radar) sensor images. The Sentinel-1A/B raw data were pre-processed using the SNAP (Sentinel Application Platform) tool provided from ESA (European Space Agency), and then the pre-processed data were converted to the backscatter coefficients. The regression equations were derived based on the relationships between the TDR (Time Domain Reflectometry)-based soil moisture measurements and the converted backscatter coefficients. The TDR measurements from the 51 RDA (Rural Development Administration) monitoring sites were used to derive the regression equations. Then, the soil moisture values were estimated using the derived regression equations with the input data of Sentinel-1A/B based backscatter coefficients. Overall, the soil moisture estimates showed the linear trends compared to the TDR measurements with the high Pearson's correlations (more than 0.7). The Sentinel-1A/B based soil moisture values matched well with the TDR measurements with various land surface conditions (bare soil, crop, forest, and urban), especially for bare soil (R: 0.885~0.910 and RMSE: 3.162~4.609). However, the Mandae-ri (forest) and Taean-eup (urban) sites showed the negative correlations with the TDR measurements. These uncertainties might be due to limitations of soil surface penetration depths of SAR sensors and complicated land surface conditions (artificial constructions near the TDR site) at urban regions. These results may infer that qualities of Sentinel-1A/B based soil moisture products are dependent on land surface conditions. Although uncertainties exist, the Sentinel-1A/B based high-resolution soil moisture products could be useful in various areas (hydrology, agriculture, drought, flood, wild fire, etc.).

• 인간식물환경학회지
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• 제23권5호
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• pp.507-519
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• 2020

Background and objective: This study analyzed the growth characteristics, in relation to the soil moisture content, of trees planted in an environment with limited soil depth to provide the baseline data for effective irrigation management. Methods: The experimental treatment was divided into soil moisture contents (SMC) of 20%, 15%, 10%, 5%, and 1%, and the respective watering times were set accordingly. As for plant materials, Nandina domestica, Euonymus alatus, Thuja occidentalis, Hibiscus syriacus, Pinus densiflora, and Pyracantha angustifolia, were chosen for this study, because they are highly likely to be used in urban street environments. Results: The minimum irrigation point suitable for each species was determined by considering various aspects of visual quality and water efficiency in terms of plant growth, including characteristics such as height, root diameter, rootlet development, and weight. Our results indicate that N. domestica should be watered so that the moisture content of the soil is of at least 5%, based on the balance between the stem and roots, as well as on visual quality. E. alatus and P. angustifolia are suitable for watering that results in at least 10% SMC, considering the height, root growth, weight, and visual quality of plants. As for T. occidentalis, it showcases moderate growth with a soil moisture content of at least 5%. Finally, the minimum irrigation time required to obtain 15% SMC is appropriate, in terms of plant growth, fresh weight, and visual quality, for H. syriacus and P. densiflora. Conclusion: This study suggested a basic irrigation guideline for container gardens where trees planted in environments with limited soil depth can be managed so that they are visually appropriate and in good condition of growth.

• 환경영향평가
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• 제25권2호
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• pp.155-164
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• 2016

토양 환경은 그 유한성과 다양한 기능의 가치로 인해 중요한 자원으로 인식되고 있다. 따라서 많은 나라에서 토양의 질과 관련된 인자를 활용한 전략환경영향평가를 수행하고 있다. 하지만 우리나라는 아직까지도 오염도 위주의 제한된 인자만을 사용하고 있다. 본 연구에서는 개발기본계획에 대한 전략환경영향평가에서 토양의 복합적 특성을 고려할 수 있도록 개선하고 이를 보금자리주택 공급계획과 도시관리계획에 시범 적용하였다. 토양을 고려한 전략환경영향평가는 체크리스트 방법을 사용하여 상위계획과의 연계성, 대안 설정 분석, 입지의 타당성을 평가하였다. 평가 결과, 토양 유기물과 토양 침식 항목이 개발기본계획에서 가장 중요하게 고려해야 하는 인자로 도출되었다. 다만, 상기 두 인자에 대한 데이터베이스의 준비, 평가 비용의 증가 등을 예상할 수 있지만, 본 연구에서 개선한 전략환경영향평가 기법은 토양자원 보전에 기여할 수 있을 것으로 기대된다.

• 한국환경과학회지
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• 제29권4호
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• pp.325-337
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• 2020

The purpose of this study was to analyze the soil environment of urban neighborhood parks and to use them as basic data for evaluating the ecological functions of urban parks such as groundwater regeneration, flood control, microclimate regulation, adsorption and purification. The landscape design criteria were generally evaluated as advanced, and further monitoring and studies are needed to evaluate the various ecological functions. It is also necessary to improve the phosphoric acid and nitrogen contents, which tended to be low. In addition, continuous monitoring is needed to assess the proper soil environment according to the biological species, and to evaluate the ecological functions. The results of this study can be used to evaluate the groundwater recharge of urban parks. In particular, when the land of the neighboring park is used for various purposes, the level of access of the user may be increased. Therefore, factors that may adversely affect the user's health, such as heavy metals and organic matters, should be selected and selected as management criteria. In addition, follow-up studies considering fertilization standards suitable for trees and growth of introduced vegetation, etc. are needed urgently to improve the soil environment.