• Geophysics and Geophysical Exploration
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• v.16 no.3
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• pp.109-118
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• 2013

On and near the 23-m high earthen Cheongcheon dam in Boryeong City, Korea, short seismic refraction and surface-wave profiles were conducted using a 5-kg sledgehammer. From vertical and horizontal components of the seismic waves, near-surface P-wave velocities (${\nu}_p$) and S-wave velocities (${\nu}_s$) were derived by inverting first-arrival refraction times and dispersion curves of Rayleigh waves. Average ${\nu}_p$ and ${\nu}_s$ for the Jurassic sedimentary basement were determined to be 1650 and 950 m/s at a depth of 30 m directly beneath the dam and 1650 m/s and 940 m/s at a depth of 10 m at the toe of the dam, respectively. The dynamic Poisson's ratio for these strata were therefore in the range of 0.24 to 0.25, which is consistent with ratios for consolidated sedimentary strata. Near a 45-m borehole 152 m downstream from the dam crest, an SH tomogram indicates a refraction boundary with an average ${\nu}_s$ of 870 m/s at depths of 10 ~ 12 m. At this site, the overburden comprises the upper layer with relatively constant ${\nu}_p$ and ${\nu}_s$ around 500 and 200 m/s, respectively, and the lower layer in which both ${\nu}_p$ and ${\nu}_s$ increase with depth almost linearly. The dynamic Poisson's ratios for the overburden were in the range of 0.30 to 0.43.

• Korean Journal of Environment and Ecology
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• v.28 no.3
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• pp.314-325
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• 2014

We studied fish fauna at 10 study sites in Ungcheon stream for 4 times from April to October, 2011 to investigate the influence of artificial structures such as dam (with fish-way) and weir (without fish-way), and abandoned mine on fish community. A total of 12 families, 36 species of fishes were collected. Dominant species was Zacco platypus (23.4%) and subdominant species was Zacco koreanus (20.5%). Ten species (27.8%) of Korean endemic species and Micropterus salmoides, exotic species, were observed during the study period. Endangered species of Korea such as Pseudopungtungia nigra and Liobagrus obesus, and Korean endemic species, Coreoperca herzi, which are vulnurable for water quality and had been observed in previous study, were not identified in this study. According to the cluster analysis, Ungcheon stream were divided into three groups consisting upstream (St.1, St.2, St.3), midstream (St.4, St.5, St.6, St.7), downstream (St.8, St.9, St.10). Community structure similarity between upper and lower site of Boryeong dam with fish-way (St.6-St.7) was high, whereas that of weir, lack of fish-way (St.7-St.8) showed little similarity indicating that fish-way was required. According to the canonical correlation analysis, high level of conductivity and salinity at upstream was detected and Misgurnus mizolepis, and endemic species of Korea such as Silurus microdorsalis, Coreoleuciscus splendidus and Iksookimia koreensis were observed at this part of the stream. Since Korean endemic species, Squalidus gracilis majimae cohabit with exotic species, M. Salmoides at downstream whose width is wide and water velocity is low, protection was needed for these endemic species.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.2
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• pp.44-55
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• 2018

The importance of establishing a greenhouse gas inventory is emerging for policymaking and its implementation to cope with climate change. Thus, it is needed to establish Approach 3 level Land Use, Land-Use Change and Forestry (LULUCF) matrix that is spatially explicit regarding land use classifications and changes. In this study, four types of spatial information suitable for establishing the LULUCF matrix were analyzed - Cadastral Map, Land Cover Map, Forest Map, and Biotope Map. This research analyzed the classification properties of each type of spatial information and compared the quantitative and qualitative characteristics of the maps in Boryeong city. Drawn from the conclusions of the quantitative comparison, the forest area showed the maximum difference of 50.42% ($303.79km^2$) in the forest map and 46.09%($276.65km^2$) in the cadastral map. The qualitative comparison drew five qualitative characteristics: data construction scope difference, data construction purpose difference, classification standard difference, and classification item difference. As a result of the study, it was evident that the biotope map was the most appropriate spatial information for the establishment of the LULUCF matrix. In addition, if the LULUCF matrix is made by integrating the biotope, the forest map, and the land cover map, the limitations of each spatial information would be improved. The accuracy of the LULUCF matrix is expected to be improved when the map of the level-3 land cover map and the biotope map of 1:5,000 covering the whole country are completed.

• Journal of the Korean earth science society
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• v.31 no.1
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• pp.18-35
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• 2010

Facies analysis of the Late Triassic Hajo Formation, the lowest stratigraphic unit in the Chungnam Basin, shows that the lower part is composed mainly of breccias or conglomerates; the middle part, conglomerates; and the upper part, conglomerates and sandstones. The formation consists of 13 facies, which include horizontally stratified clastsupported conglomerate, clast-supported massive breccia, matrix-supported massive breccia or conglomerate, matrixsupported graded conglomerate, massive pebbly sandstone, horizontally laminated sandstone, massive sandstone, graded sandstone, inversely graded sandstone, planar cross-bedded sandstone, trough cross-bedded sandstone, low angle crossbedded sandstone, and massive mudstone. These are grouped into 4 facies associations (FA). FA I consisted of clastsupported and matrix-supported massive breccias presumably deposited in the talus or upper fan delta environment. FA II consists of matrix-supported massive conglomerate and horizontally stratified clast-supported conglomerate of cobble size and it seems to have been deposited in the upper fan delta environment. FAIII consisted of matrix-supported massive conglomerate of pebble size, horizontally laminated sandstone and massive sandstone may have been deposited in the middle fan delta environment. FAIV consists of massive pebbly sandstone, horizontally laminated sandstone and massive sandstone and presumably was deposited in the lower fan delta environment. In general the Hajo Formation is interpreted to have been deposited at the talus/upper fan delta environment in early stage; it might have been deposited in the alternating environments of upper and middle fan delta in middle stage; and it seems to have been deposited in alternating environments of middle and lower fan delta in late stage.

• Economic and Environmental Geology
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• v.37 no.6 s.169
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• pp.585-601
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• 2004

A general study of domestic black sandstone and black shale quarries has not been made. For this reason it is difficult to know how the matter really stands. The objectives of this study are to achieve systematical and scientific study of the distribution, occurrences and rock quality of black sandstone and black shale resources exploited in existing quarries in the Boryeong area. The black sandstone bed survey was made from 54 mine claims on 4 sheets. In the area, 140 black sandstone and 22 black shale quarries were ascertained in 37 mine claims. The general development information data from that existing quarries were collected and synthesized. Among these black sandstone quarries for gravestones, monuments and black shale quarries for inkstone are in operation. Most of the black sandstone quarries were closed throughout the Gaewhari, Suburi, Seongjuri district in the investigated area even though these quarries had played a prominent part in the production of black sandstone. In view of commercial dimension stones, raw materials from black sandstone are classified as corestone and fresh rock body according to the characteristics of their occurrences and shape. Black sandstone beds are characteristically well-jointed and are particularly subdivided into cubic or quadrangular blocks in 3 joint sets. The colors of these black sandstones show medium dark $gray\~grayish$ black judging from the Rock Color Chart. The black sandstone beds which are intercalated in the Amisan, Jogeri, Baegunsa, Seongjuri Formations of the Daedong Supergroup are about $1\~10\;m$ in thickness.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.543-553
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• 2013

In Korea, there have been many studies and progresses on various types of pilot scale or commercialized field scale Best Management Practices(BMP) during the last 10 years. Runoff characteristics of diffuse pollutants from different land uses are well identified and documented. However, for the coastal area connected directly with shoreline, runoff patterns and management schemes of non-point pollution were not fully studied. Recently, coastal area is emerging as a new development axis especially in west coast side of Korea such as Incheon city and Chungnam province, thus urbanized area rapidly increased but there are no buffer zones and BMP facilities to aim at preventing direct discharge of the first flush into coastal sea and beaches. In this study, parking area in Deacheon harbor, Boryeong City in Chungnam Province was selected and rainfall runoff was monitored for two year period in order to examine run-off features from which proper type of BMP suitable for coastal area is proposed. Coastal area usually has a low ground water level and consists of plain land, so that large scale BMP such as storm water retention pond and wetland requiring great excavation works is not best management plan. In addition, monitoring study shows that storm water from the paved parking area has a high salinity compared with those in storm water from the inland. High salinity is detrimental for the vegetation. Therefore, BMP employing least vegetative cover and also in terms of maintenance is a good option such as infiltration trench and porous pavement.

• Journal of Environmental Impact Assessment
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• v.24 no.1
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• pp.35-50
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• 2015

The purposes of this study are to apply species distribution modeling in urban management planning for habitat conservation in non-urban area and to provide a detailed classification method for management zone. To achieve these objectives, Species Distribution Model was used to generate species richness and then to compare with the results from land suitability assessment. 59 species distribution models were developed by Maxent. This study used 15 model variables (5 topographical variables, 4 vegetation variables, and 6 distance variables) for Maxent models. Then species richness was created by sum of predicted species distributions. Land suitability assessment was conducted with criteria from type I of "Guidelines for land suitability assessment". After acquiring evaluation values from species richness and land suitability assessment, the results from these two models were compared according to the five grades of classification. The areas with the identical grade in Species richness and land suitability assessment are categorized and then compared each other. The comparison results are Grade1 10.92%, Grade2 37.10%, Grade3 34.56%, Grade4 20.89% and Grade5 1.73%. Grade1 and Grade5 showed the lowest agreement rate. Namely, development or conservation grade showed high disagreement between two assessment system. Therefore, the areas located between urban, agriculture, forest, and reserve have a tendency to change easily by development plans. Even though management areas are not the core area of reserve, it is important to provide a venue for species habitat and eco-corridor to protect and improve biodiversity in terms of landscape ecology. Consequently, adoption of species richness in three levels of management area classification such as conservation, production, planning should be considered in urban management plan.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.644-655
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• 2020

This study focuses on the margin of human error when a navigator is embarrassed by the psychological fear of collision in a close-quarter situation (CQS) and is unable to perform as per the prescribed collision avoidance measures. The purpose of the study is to identify the effects of the navigator's personal characteristics or factors in relation to on-board career (OC), license rating (LR), and age on the perceived collision risk (PCR) in CQSs. In order to obtain quantified data regarding the collision risk perceived by the navigator in four typical CQSs between their own ship and a target ship, this study measured and collated the heart rate variability of 30 navigators on their own ship when two ships approached each other at a speed of 10 knots from 2.5 nautical miles to a collision situation. According to a multiple regression analysis of the measured values, the navigators' OC and LR factors had negative effects on the PCR, while the age factor had no significant effect on PCR. The t-test results showed that the PCR value was significantly higher for navigators with an OC ≤ 4 years than for those with an OC ≥ 5 years, and the LR factor was significantly higher for a class 4~6 group than for a class 2~3. This finding may be applied to the development of collision risk warning systems, particularly for navigators.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.129-138
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• 2020

This study recognizes problems in the current system of providing navigation safety information (NSI), which is centered on merchant ships, to prevent maritime accidents of fishing boats and small vessels in coastal areas. The system proposed in this study is an effective method of providing NSI to support the safe navigation of small vessels such as fishing boats. First, the status and characteristics of recent maritime accidents were examined, and NSI service targets were identified. Second, the limitations of the current NSI system were determined, and measures were proposed to establish an NSI Integrated Platform (NSIP) that ensures the integration, accessibility, and usability of NSI for a substantial portion of the public. Third, to utilize the NSIP, various NSIs are applied as additional information for the electronic chart system used in the e-navigation ship terminals being developed in connection with the Korean e-navigation project. Functions that set the audiovisual alarm function to automatically operate when a ship enters a navigation risk zone is proposed. These functions are technically achieved by reviewing expert opinions of related organizations and professional producers. The results of this study suggest that NSI can be applied to small vessels such as fishing boats, through the Korean e-Navigation project, to prevent maritime accidents caused by the human error of navigators.

• Korean Journal of Construction Engineering and Management
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• v.18 no.4
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• pp.36-47
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• 2017

As a typical domestic subsea tunnel construction the Gadeok subsea tunnel applying the method of immersed tunnel has been completed and the Boryeong-Taean subsea tunnel is under construction using NATM. The high-speed railway subsea tunnels between the Honam and Jeju are under consideration, and the feasibility of constructing subsea tunnels with Japan and China is also under consideration. However, it is difficult to provide the process plan information for the construction work such as the analysis of the feasibility of the subsea tunnel and the prediction of the proper construction period because there is no case of domestic construction for it applying the shield TBM method. Due to economic and other reasons, government organizations are reluctant to apply the shield TBM, and there is lack of data on the construction process management field using the shield TBM method. Therefore, a standard construction process management system for the subsea tunnel is needed to analyze the feasibility of the subsea tunnel and to predict the proper construction period. By presenting the standard construction process management system of subsea tunnels such as WBS, Network Diagram, and construction period calculation model, I hope to contribute technically and economically to future subsea tunnel projects.