• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.379-384
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• 2009

This study was carried out to understand the national and regional distribution of the biomass resources produced in Korea annually via establishing database (DB) and distribution maps of biomass resources data including as livestock manures, food wastes and agricultural by-product. The information of the annual production of each biomass resources was obtained from Ministry for Food, Agriculture, Forestry and Fisheries (MIFAFF), Ministry of Environment (MOE) and National Statistical Office (NSO). Based on biomass resources data, we established database architecture table about livestock manures and food wastes. The distribution maps for the total amount of manures produced from each livestock animal were built up in both national and regional scales and used for analysis of the space-based and time-based distribution of the manure resources. Distribution maps for food wastes and agricultural by-product were also produced, respectively. It was shown that the analysis through resource mapping can be used to identify the sources of collectable biomass feasibly determining suitable region for establishment of a biomass-energy production. The biomass distribution maps graphically provide the information regarding biomass resources to policy-makers, farmers, general users and it was expected to be utilized for policy-making of environmental-friendly agriculture and bio-energy.

• Korean Journal of Remote Sensing
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• v.37 no.6_3
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• pp.1951-1963
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• 2021

Remote sensing data using earth observation satellites in agricultural environment monitoring has many advantages over other methods in terms of time, space, and efficiency. Since the sensor mounted on the satellite measures the energy that sunlight is reflected back to the ground, noise is generated in the process of being scattered, absorbed, and reflected by the Earth's atmosphere. Therefore, in order to accurately measure the energy reflected on the ground (radiance), atmospheric correction, which must remove noise caused by the effect of the atmosphere, should be preceded. In this study, atmospheric correction sensitivity analysis, inter-satellite cross-analysis, and comparative analysis with ground observation data were performed to evaluate the application of KOMPSAT-3 satellite's atmospheric correction for agricultural application. As a result, in all cases, the surface reflectance after atmospheric correction showed a higher mutual agreement than the TOA reflectance before atmospheric correction, and it is possible to produce the time series vegetation index of the same standard. However, additional research is needed for quantitative analysis of the sensitivity of atmospheric input parameters and the tilt angle.

• Applied Chemistry for Engineering
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• v.29 no.6
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• pp.696-702
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• 2018

Recently, the current thermal battery technology needs new materials for electrodes in the power and energy density to meet various space and defense requirements. In this paper, to replace the pellet type Li(Si) anode having limitations of the formability and capacity, electrochemical properties of the lithium anode with high density for thermal batteries were investigated. The lithium anode (Li 17, 15, 13 wt%) was fabricated by mixing the molten lithium and iron powder used as a binder to hold the molten lithium at $500^{\circ}C$. The single cell with 13 wt% lithium showed a stable performance. The 2.06 V (OCV) of the lithium anode was significantly improved compared to 1.93 V (OCV) of the Li(Si) anode. Specific capacities during the first phase of the lithium anode and Li(Si) were 1,632 and $1,181As{\cdot}g^{-1}$, respectively. As a result of the thermal battery performance test at both room and high temperatures, the voltage and operating time of lithium anode thermal batteries were superior to those of using Li(Si) anode thermal batteries. The power and energy densities of Li anode thermal batteries were also remarkably improved.

• Journal of the Korean earth science society
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• v.39 no.6
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• pp.533-544
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• 2018

Rainfall is one of the most important meteorological variables in meteorology, agriculture, hydrology, natural disaster, construction, and architecture. Recently, satellite remote sensing is essential to the accurate detection, estimation, and prediction of rainfall. In this study, the accuracy of Integrated Multi-satellite Retrievals for GPM (IMERG) product, a composite rainfall information based on Global Precipitation Measurement (GPM) satellite was evaluated with ground observation data in the inland of Korea. The Automatic Weather Station (AWS)-based rainfall measurement data were used for validation. The IMERG and AWS rainfall data were collocated and compared during one year from January 1, 2016 to December 31, 2016. The coastal regions and islands were also evaluated irrespective of the well-known uncertainty of satellite-based rainfall data. Consequently, the IMERG data showed a high correlation (0.95) and low error statistics of Bias (15.08 mm/mon) and RMSE (30.32 mm/mon) in comparison to AWS observations. In coastal regions and islands, the IMERG data have a high correlation more than 0.7 as well as inland regions, and the reliability of IMERG data was verified as rainfall data.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.2
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• pp.24-35
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• 2019

In this study, a hotspot analysis was conducted to suggest a new method for interpreting soil heavy-metal contamination data of abandoned metal mines according to statistical significance level. The spatial autocorrelation of the data was analyzed using the Getis-Ord $Gi{\ast}$ statistic in order to check whether soil heavy metal contamination data showing abnormal values appeared concentrated or dispersed in a specific space. As a result, the statistically significant data showing abnormal values in the mine area could be classified as follows: (1) the contamination degree and the hotspot value (z-score) were both high, (2) the contamination degree was high but the z-score was low, (3) the contamination degree was low but the z-score was high and (4) the contamination degree and the z-score were both low. The proposed method can be used to interpret the soil heavy metal contamination data according to the statistical significance level and to support a rational decision for soil contamination management in abandoned mines.

• Tunnel and Underground Space
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• v.29 no.4
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• pp.230-242
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• 2019

While various automatic rock fracture survey methods have been researched, the evaluation of the accuracy of these methods raises issues due to the absence of a metric which fully expresses the similarity between automatic and manual fracture maps. Therefore, this paper proposes a geometry similarity metric which is especially designed to determine the overall similarity of fracture maps and to evaluate the accuracy of rock fracture survey methods by a single number. The proposed metric, Scanline Intersection Similarity (SIS), is derived by conducting a large number of scanline surveys upon two fracture maps using Python code. By comparing the frequency of intersections over a large number of scanlines, SIS is able to express the overall similarity between two fracture maps. The proposed metric was compared with Intersection Over Union (IoU) which is a widely used evaluation metric in computer vision. Results showed that IoU is inappropriate for evaluating the geometry similarity of fracture maps because it is overly sensitive to minor geometry differences of thin elongated objects. The proposed metric, on the other hand, reflected macro-geometry differences rather than micro-geometry differences, showing good agreement with human perception. The metric was further applied to evaluate the accuracy of a deep learning-based automatic fracture surveying method which resulted as 0.674 (SIS). However, the proposed metric is currently limited to 2D fracture maps and requires comparison with rock joint parameters such as RQD.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.553-563
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• 2018

In this study, the location conditions and optimal technologies required for creating urban municipalities that can utilize the space in an abandoned mine area, where there is no infrastructure related to recycling wastes and valuable metals, are investigated. The urban mining industry deals with mineral resources through the processing of high value-added industrial by-products and wastes, and it is a useful linkage industry for the development of mineral resources and prevention of mining hazards. Urban mining technologies targeted at the abandoned mine area constitute screening, extraction, and smelting for recycling waste products. By analyzing the technologies available, an industrial network can be developed for recycling waste batteries and catalysts, which are promising raw materials. It is also important to establish an appropriate location for related industries that can generate value-added resources, rather than the resource supply and demand conditions seen in general urban mines. In order to overcome the accessibility and infrastructure limitations, the economic foundation of the abandoned mine area should consider the linkage of raw material supply, key technologies for recycling useful mineral resources that are derived from urban mines, spatial and site conditions, and industrial characteristics.

• Tunnel and Underground Space
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• v.30 no.6
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• pp.559-572
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• 2020

This paper performs laboratory experiments for borehole stability considering temperature and true triaxial stress condition, and observes a thermo-mechanical behavior of the rock under stress and temperature conditions of deep underground. China yellow sandstone and Hwangdeung granite specimens were used to perform a true triaxial compression test. Mechanical tests were carried out under nine confining pressure conditions, and thermo-mechanical tests using granite samples were carried out under six confining pressure conditions at 60-100℃. In the mechanical tests, maximum principal stress at borehole breakout was proportional to intermediate principal stress. In the thermo-mechanical tests, it was confirmed that thermal stress is added to the stress field of the borehole with the increase in temperature, resulting in additional breakout progress. To analyze the results of the laboratory experiment, Mogi-Coulomb failure criterion was used. The results of traditional triaxial compression test on cylindrical specimens and borehole breakout under true triaxial compressions matched well with Mogi-Coulomb failure criterion.

• Tunnel and Underground Space
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• v.31 no.3
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• pp.145-166
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• 2021

Korea Stress Map database is built by integrating actual data of 1,400 in-situ stress measurements using hydraulic fracturing and overcoring method in South Korea. Korea Stress Map 2020 is presented based on the guideline proposed by World Stress Map Project. As detailed data, stress ratio and maximum horizontal stress direction distribution for each region are also presented. The dominant maximum horizontal stress direction in the Korean Peninsula is from northeast to southeast, and the magnitude of the in-situ stress is relatively distributed. There is some stress heterogeneity caused by local characteristics such as topographical and geological properties. We investigated case studies in which the in-situ stress was affected by mountainous topography, difference in rock quality of fracture zone, presence of mine or underground cavities, and geological structure of fault zone.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.2
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• pp.109-117
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• 2022

There has been an increasing number of studies on photovoltaic energy generation system in an offshore site with the largest energy generation efficiency, as increasing the researches and developments of renewable energies for use of offshore space and resources to replace existing fossil fuels and resolve environmental challenges. For installation and operation of floating photovoltaic systems in an offshore site with harsher environmental conditions, a stiffness of structural members comprising the total system must be reinforced to inland water spaces as dams, reservoirs etc., which have relatively weak condition. However, there are various limitations for the reinforcement of structural stiffness of the system, including producible size, total mass of the system, economic efficiency, etc. Thus, in this study, a floating breakwater is considered for reducing wave loads on the system and minimizing the reinforcement of the structural members. Wave reduction performances of floating breakwaters are evaluated, considering size and distance to the system. The wave loads on the system are evaluated using the higher-order boundary element method (HOBEM), considering the multi-body effect of buoys. Stresses on structural members are assessed by coupled analyses using the finite element method (FEM), considering the wave loads and hydrodynamic characteristics. As the maximum stresses on each of the cases are reviewed and compared, the effect of floating breakwater for floating photovoltaic system is checked, and it is confirmed that the size of breakwater has a significant effect on structural responses of the system.