• Economic and Environmental Geology
• /
• v.40 no.6
• /
• pp.727-738
• /
• 2007

The present study investigation the geochemical characteristics of the stream sediments in the Unbong area was conducted to enable a understanding the natural background and a prediction the prospects of geochemical disaster as a result of that bed rocks(mylonitic granites, Kim et al., 1992). We systematically collected seventy three stream sediments samples by wet sieving along the primary channels. Major, trace and rare earth element(REE) concentrations, combined with mineralogical characteristics, were determined by XRD, XRF, ICP-AES and NAA analysis methods. Major element concentrations for the stream sediments in the Unbong area were $SiO_2\;36.94{\sim}65.39wt.%,\;Al_2O_3\;10.15{\sim}21.77wt.%,\;Fe_2O_3\;3.17{\sim}10.90wt.%,\;CaO\;0.55{\sim}5.27wt.%,\;MgO\;0.52{\sim}4.94wt.%,\;K_2O\;1.38{\sim}4.54wt.%,\;Na_2O\;0.49{\sim}3.36wt.%,\;TiO_2\;0.39{\sim}1.27wt.%,\;MnO\;0.04{\sim}0.22wt.%,\;P_2O_5\;0.08{\sim}0.54wt.%$. Trace and REE concentrations for the stream sediments were $Cu\;4.8{\sim}134ppm,\;Pb\;24.2{\sim}82.5ppm,\;Sr\;95.9{\sim}739ppm,\;V\;19.9{\sim}124ppm,\;Zr\;52.9{\sim}145ppm,\;Li\;25.2{\sim}3.3ppm,\;Co\;3.87{\sim}50.0ppm,\;Cr\;17.4{\sim}234ppm,\;Hf\;3.93{\sim}25.2ppm,\;Sc\;4.60{\sim}20.6ppm,\;Th\;3.82{\sim}36.9ppm,\;Ce\;45.7{\sim}243ppm,\;Eu\;0.89{\sim}2.69ppm,\;Yb\;1.42{\sim}5.18ppm$. According to the comparison of average major element concentrations, CaO, $Na_2O\;and\;K_2O$ contents are higher in stream sediments than in bed rocks(mylonitic granites, Kim et al., 1992) $Al_2O_3\;and\;SiO_2$ contents show good correlation both stream sediments and bed rocks(mylonitic granites, Kim et al., 1992). Yb and Eu in the stream sediments show a positive correlation with $SiO_2$. In contrast, the stream sediments display a negative correlation.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.16 no.4
• /
• pp.155-168
• /
• 2011

Coastal boundary current flows along the eastern boundary of the Yellow Sea and its speed was about 0.l m/s during the summer 2007. In order to find major factors that affect the coastal boundary current in the eastern Yellow Sea, three-dimensional numerical model experiments were performed. The model simulation results were validated against hydrographic and current meter data in the eastern Yellow Sea. The eastern boundary current flows along the bottom front over the upper part of slopping bottom. Strength and position of the current were affected by tides, winds, local river discharge, and solar radiation. Tidal stirring and surface wind mixing were major factors that control the summertime boundary currents along the bottom front. Tidal stirring was essential to generate the bottom temperature front and boundary current. Wind mixing made the boundary current wider and augmented its north-ward transport. Buoyancy forcing from the freshwater input and solar radiation also affected the boundary current but their contributions were minor. Strong (weak) tidal mixing during spring (neap) tides made the northward transport larger (smaller) in the numerical simulations. But offshore position of the eastern boundary current's major axis was not apparently changed by the spring-neap cycle in the mid-eastern Yellow Sea due to strong summer stratification. The mean position of coastal boundary current varied due to variations in the level of wind mixing.

• The Journal of Engineering Geology
• /
• v.32 no.4
• /
• pp.585-596
• /
• 2022

This study determined major factors influencing landslide occurrence along a forest road near Sangsan village, Sancheok-myeon, Chungju-si, Chungcheongbuk-do, South Korea. Within a 2 km radius of the study area, landslides occur intensively during periods of heavy rainfall (August 2020). This makes study of the area advantageous, as it allows examination of the influence of only geological and tomographic factors while excluding the effects of rainfall and vegetation. Data for 82 locations (37 experiencing landslides and 45 not) were obtained from geological surveys, laboratory tests, and geo-spatial analysis. After some data preprocessing (e.g., error filtering, minimum-maximum normalization, and multicollinearity), structural equation model (SEM) and logistic regression (LR) analyses were conducted. These showed the regolith thickness, porosity, and saturated unit weight to be the factors most influential of landslide risk in the study area. The sums of the influence magnitudes of these factors are 71% in SEM and 83% in LR.

• Korean Journal of Remote Sensing
• /
• v.39 no.3
• /
• pp.363-370
• /
• 2023

Various earth observation satellites need to provide accurate and high-quality data after launch. To maintain and enhance the quality of satellite data, it is crucial to employ a cross-calibration process that accounts for differences in sensor characteristics, such as the spectral band adjustment factor (SBAF). In this study, we utilized Landsat-8 and Sentinel-2A satellite imagery collected from desert sites in Libya4, Algeria3, and Mauritania2 among pseudo-invariant calibration sites to calculate and apply SBAF, thereby compensating the uncertainties arising from variations in bandwidths. We quantitatively compared the reflectance differences based on the similarity of bandwidths, including Blue, Green, Red, and both the near-infrared (NIR) narrow, and NIR bands of Sentinel-2A. Following the application of SBAF, significant results with reflectance differences of approximately 1% or less were observed for all bands except NIR. In the case of the Sentinel-2A NIR band, it exhibited a significantly larger bandwidth difference compared to the NIR narrow band. However, after applying SBAF, the reflectance difference fell within the acceptable error range (5%) of 1-2%. It indicates that SBAF can be applied even when there is a substantial difference in the bandwidths of the two sensors, particularly in situations where satellite utilization is limited. Therefore, it was determined that SBAF could be applied even when the bandwidth difference between the two sensors is large in a situation where satellite utilization is limited. It is expected to be helpful in research utilizing the quality and continuity of satellite data.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.14 no.5
• /
• pp.1-12
• /
• 2015

Length and the number of tunnels has increased 10% annually. Tunnel construction has positive effect in nature and driving condition. However, the structure of tunnels lead to a greater probability of major accidents. For this reason, tunnel is focusing its attention on the rapid incident handling and disaster management to build a tunnel management system in recently. In this study, tunnel management system adequacy analyzed in terms of operational safety using IPA and AHP analysis. IPA analysis results using the portfolio chart, incident management factors has a large gap between important and satisfaction. Disaster management is analyzed high ranking in priority. However, incident management factors are derived first priority in AHP analysis. This study determined that the results are meaningful to practitioners in the field is determined. In addition, practitioners comments should be reflected primarily for tunnel operational safely.

• Journal of Korea Water Resources Association
• /
• v.42 no.8
• /
• pp.643-657
• /
• 2009

The major reason to construct large dams is to store surplus water during rainy seasons and utilize it for water supply in dry seasons. Reservoir storage has to meet a pre-defined target to satisfy water demands and cope with a dry season when the availability of water resources are limited temporally as well as spatially. In this study, a Hedging rule that reduces total reservoir outflow as drought starts is applied to alleviate severe water shortages. Five stages for reducing outflow based on the current reservoir storage are proposed as the Hedging rule. The objective function is to minimize the total discrepancies between the target and actual reservoir storage, water supply and demand, and required minimum river discharge and actual river flow. Mixed Integer Linear Programming (MILP) is used to develop a multi-reservoir operation system with the Hedging rule. The developed system is applied for the Han River basin that includes four multi-purpose dams and one water supplying reservoir. One of the fours dams is primarily for power generation. Ten-day-based runoff from subbasins and water demand in 2003 and water supply plan to water users from the reservoirs are used from "Long Term Comprehensive Plan for Water Resources in Korea" and "Practical Handbook of Dam Operation in Korea", respectively. The model was optimized by GAMS/CPLEX which is LP/MIP solver using a branch-and-cut algorithm. As results, 99.99% of municipal demand, 99.91% of agricultural demand and 100.00% of minimum river discharge were satisfied and, at the same time, dam storage compared to the storage efficiency increased 10.04% which is a real operation data in 2003.

• Journal of the Society of Disaster Information
• /
• v.16 no.3
• /
• pp.479-492
• /
• 2020

Purpose: The purpose of this study is to analyze the impact of regional characteristics on population movement on the Seoul metropolitan areas. Method: To this end, 66 basic entities in the Seoul metropolitan area were divided into three regions by analyzing the demographic movement data from 2010 to 2016 and the factors for determining population movement within and between regions were identified by applying a stepwise regression technique. Result: The major analysis confirmed that the increase in the number of apartments in all areas of the Seoul metropolitan area, the increase in the number of single-family homes, the increase in the number of employees, the increase in manufacturers, the growth rate of knowledge, culture, and leisure industries, the increase rate of GRDP, and the opening of new subway stations. In particular, the growth rate of the number of apartments, the growth rate of the knowledge, culture and leisure industries, the increase rate of GRDP, and the opening of new subway stations played a positive role in increasing population inflow. Conclusion: The result showed that by region, the growth rate of knowledge, culture and leisure industries contributed greatly to the inflow of population in the first region, and that the opening of new subway stations and the increase of GRDPs were the main factors. The increase in the number of apartments and subway stations were the main factors in the three areas.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.5 no.4
• /
• pp.255-260
• /
• 2003

Recently, both climate change and unusual meteorological disasters are becoming a more frequent and serious threat to agricultural production. Destruction of the stabilizing base of agricultural productivity in Korea is a concern. This study provides basic information for stabilizing agricultural production by clarifying and analyzing the features of agro-meteorological disasters which have occurred recently in Korea. The occurrence of meteorological disasters has increased rapidly since the 1940s. A 19-fold increase in occurrence is noted over the past 60 years from 1941 to 2000. Meteorological disasters occurred mostly in August, then in July, and least often in October, In terms of regional occurrences, the frequency of meteorological disasters was the highest in Gangwon (751 times) and in Jeonnam (703 times) provinces, and the lowest in Jeju (459 times) province for the 97 years from 1904 to 2000. Agro-meteorological disasters which caused the most serious damage to cropland were rain storms and typhoons for the 10 years from 1991 to 2000, and they occurred 52 and 18 times during this period, respectively. Agro-meteorological disasters occurred mainly during the summer season (from June to September) when major crops are cultivated in Korea.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.1 no.2 s.2
• /
• pp.123-137
• /
• 2001

Based on basic characteristics of urban disasters and their data availabilities in Korea, this study provides risk assessment models which are derived from Cheongju examples. In specific, the application models are confined to fire, facility and escape risk survey results in the paper. For the assessment criteria, major independent variables for the categories of fire include both the frequency levels and the amount of damage. And the degree of facility risk assessment is heavily hinged on both the weighted values of key facilities and their weighted rank-sizes. In the same context, the degree of escape risk assessment is hinged on both the weighted values and the amount of the classification of land. From the empirical configuration, this paper presents that the potential figure of fire risk is relatively higher in the built-up areas within the existing Central Business District where accommodates a number of dilapidated housing units and community-supportive facilities. In contrast, the potential figure of facility and escape risk is higher in both old residential areas and the newly-built apartment complex. In short, the CBD and its neighboring residential areas record a high potential figure in terms of total risk, juxtaposing fire, facility and escape risk all together.

• Journal of the Korean Society for information Management
• /
• v.37 no.2
• /
• pp.251-284
• /
• 2020

As the use of information has emerged as the core of national competitiveness, major developed countries and the Korean government have realized the importance of data. They have pursued technical research and standard establishment for long-term preservation and continuously strived for systematic management and preservation of data. However, although various types of data are specified for the purpose of record management in the law, there is no specific method on how to collect, manage and preserve them, except standard electronic documents. In particular, management and preservation of huge datasets from the administrative information system have been strongly demanded above all. Any guidelines for datasets do not have been properly provided. After the framework for selecting preservation format must be prepared, the system can be supplemented and built. The framework considering the characteristics of the dataset should be specified more concretely, and empirical verification of the conversion and restoration for the dataset preservation format derived according to the selection criteria is necessary. Therefore, this study intends to propose a method for long-term preservation through empirical verification of the preservation format after deriving an evaluation the framework for the preservation format selection criteria considering the characteristics of the dataset.