• The Journal of Engineering Geology
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• v.25 no.4
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• pp.473-484
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• 2015

Geophysical exploration using electric resistivity, ground penetrating radar (GPR), and impedance high-frequency (ZHF) surveys was conducted in Gujwa-eup, Jeju City, Jeju Island, an island in the Korea Strait, to confirm the existence of new caves near known caves. The exploration revealed a number of anomaly zones, presumed to be caves; 27 sites at suitable locations and depth ranges were selected for drilling and further surveys. However, contrary to predictions, most of the anomaly zones were clinker layers or paleosols intercalated with lavas. Only five boreholes intersected caves. The clinker layers and paleosols were possibly detected as anomalies owing to their different physical properties from the other rocks. Two of the five cave-finding boreholes penetrated Yongcheon Cave; a new cave was found at the other. The two boreholes that penetrated Yongcheon Cave were drilled in areas where the cave has not been previously reported, and thus helped correct an error in the cave distribution map. The cave newly discovered in this boring exploration is 180 m long, and it is connected to the upstream part of Dangcheomul Cave (110 m). The cave contains well-developed lava helictites, lava levees, and ropy structures; carbonate speleothems such as soda straws, stalagmites, columns, and curtain shawls are also well preserved. Notably, the unique shape of the carbonate speleothems is attributed to their growth in relation to the cavern water that flowed into the cave along plant roots.

• Korean Journal of Environmental Biology
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• v.25 no.2
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• pp.94-99
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• 2007

To investigate the spatial distribution and daily calling pattern of the Gold-spotted pond frog, Rana chosenica, in Chungju city and Chungwon gun, Chungbuk province, Korea, we divided the study area into 226 plots with a $2{\times}2km^2$ plot on the map, of which we assigned 32 plots for monitoring populations. Call monitoring on whether the species are present or not were conducted for 5 minutes in between sunset and the midnight from at the end of May to July in 2006. Gold-spotted pond frogs were detected at least once four out of 32 plots. Using program Presence, we obtained site occupancy rate as 0.170 which was quite low compared with other species, while detection probability was 0.66 that propose at least three times to visit the monitoring site to confirm the absence of the frogs. The frogs were actively calling from 21:00 to 02:00, and the number of calling male was significantly and highly correlated with water temperature and humidity. This study shows the present status of the Gold-spotted pond frogs in Chungju city and Chungwon gun and we suggests various effective monitoring methods based on the this study.

• Journal of the Korean Geographical Society
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• v.41 no.4 s.115
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• pp.391-403
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• 2006

The Hanon volcano located in the southern pan of Cheju Island, Korea has a wetland in its crater being used as a farmland. Previous researchers presumed this wetland was a maar lake in the past. Based on the seismic refraction method, the wetland sediment layer was estimated between 5 to 14 m deep, which is mostly in accordance with previous researches. However, this shows only the depths at some sites, not representing the whole spatial distribution. This study is an attempt to reconstruct the volcanic lake in Hanon crater by applying the spatial statistical techniques based on the depth information from the seismic survey and known data. The procedure of reconstruction is as follows: First, the depth information from the seismic survey and known data were collected and it was interpolated by IDW and Ordinary Kriging method. Next, with the interpolation map and the present DEM the paleo DEM was constructed. Finally, using the paleo lake level on core data, the boundary of volcanic lake was extracted from the paleo DEM. The reconstructed lake resembles a half-moon in the north of the central scoria cone. It is estimated that the lake was 5 m deep on average and 13 m deep at the deepest point. Although there are slight differences according to the interpolation techniques, it is calculated that the area of the lake was between 184,000 and $190000m^2,$ and its volume approximately $869,760m^3$. Because of the continuous deposition processes after the crater formation, the reconstructed volcanic lake would not indicate an actual lake at a specific time. Nevertheless, it offers a significant clue regarding the inner morphology and evolution of the crater.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.94-110
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• 2003

This study utilizes the dataset of Topex/Poseidon(T/P) altimeter sea surface height (1992-2000 yr., 286 cycles)to investigate the tempore-spatial variability in the East (Japan) Sea. Optimal interpolation (Ol) technique was applied to the pre-processed T/P dataset (level 2) to produce sea surface height anomaly (SSHA) map on regular grids. Spectral analyses of the timeseries of the SSHA at chosen stations and empirical orthogonal function (EOF) analysis of the SSHA in the entire East Sea were made. Distribution of the SSHA can be divided by the southern and northern regions sharply by the polar front situated in the middle of the East Sea. The southern region under the direct influence of the Tsushima Current exhibits higher amplitude of the SSHA fluctuation, while the northern region does relatively smaller one. The spatio-temporal variability of the SSHA in the East Sea can be characterized by the five modes of the EOFs accounting for more than 85% of the total variance. The first mode dominates the SSHA variation in the entire domain with strong seasonal and inter-annual periods accounting for the 72.3% of the total variance. The other modes (up to 5th account for 14%) are responsible for the SSHA variation associated with the local current system, meandering of the polar frontal axis, and mesoscale eddies. Spectral peaks with significant confluence level show semi-annual, annual and interannual (2, 3-4 years) periods.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.1
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• pp.28-38
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• 2004

The purpose of this study is to analyze the urban hydrologic state by the use of GIS, resolution and interpolation. The determination coefficient($R^2$) and Regression Formula were derived from the contour of digital map for the accuracy, and DEM data was made by using TIN interpolation by the size of the grid. By using the observed DEM data, topographical factors were extracted from the small basin, size, the width of a basin and the slope, and were applied in the urban runoff model. Through the model, we tried to find out the most suitable runoff model in a small basin of Yosu-Munsu area. As a result of applying models to the drainage considered, the runoff hydrograph estimated by SWMM model was closer to the observed one than that estimated by ILLUDAS model. The difference between the runoff hydrograph by SWMM and the observed one is maximum error of 19%, minimum error of 5% and average error of 13%. The influence of duration in contrast to pick time is insignificant in a urban small basin. As a conclusion of this study, SWMM model was more suitable and applicable for the urban runoff model than ILLUDAS model due to its accuracy and various abilities.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.1
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• pp.120-134
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• 2015

InVEST Water Yield model developed by Natural Capital Project was applied for South Korea to assess domestic forest ecosystem's water provisioning services. The InVEST Water Yield model required 8 input dataset, including six spatial map data and two derived by coefficients. By running the model with relatively easy acquired and modified data, the result of domestic forest ecosystem's water provisioning services was 9,409,622,083 ton using the standard of the year 2011. The result showed similar patterns and distribution of rainfall in 2011, but showed difference when compared with existing researches spatially driven in nationwide statistical analysis results. This difference is assumed to occur with different model mechanism in spatial implementation and statistical analysis. So given that the model is currently still developing, applications should be taken on qualitative perspectives rather than on quantitative perspectives. Additionally, for advancing the application of InVEST water yield model, quantification of suitable input data and comparison using multi-modeling is required.

• Korean Journal of Remote Sensing
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• v.20 no.2
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• pp.91-102
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• 2004

This paper reflects the estimation of using the EOC(Electro-optical Camera) images supporting GIUH(geomorphological instantaneous unit hydrograph) approach. We have analyzed GIUH in its density and frequency distribution by creating a DEM(digital elevation model) for the sub basin produced from the EOC images and examined topographical and hydrological application possibility of the EOC images. In this process, we have topographical basin characteristic analysis that use the remote sensing technique analyzing the DEM creation process of the EOC stereo images by studying the basic topographical hydrology analysis about abstraction technique since it is flirty complex and is more time-consuming than other method. we executed statistical analysis of a basin size and river length using the frequency function after divided lattice spacing applied have to the sub river basin from the image data and the digital map into 10m intervals ranging from 10m to 100m. After comparing and examining the peak and time to peak of the GIUH, we proceeded with a comparative analysis by lattice concerning the topographical divergence rate, area ratio, length ratio. Accumulating the peak and time to peak of the GIUH is altered to non-linear form in accordance to lattice dimension as well as basin factor. It was proved that the lattice dimension is one of the important factors about the peak and time to peak of the GIUH.

• Journal of The Geomorphological Association of Korea
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• v.15 no.2
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• pp.85-94
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• 2008

This study is to construe spatio-temporal characteristics of temperature in cities and changes of climatical regions in analyzing a change of Korea Peninsular climate. We used daily mean air temperature data which was collected in South and North Korea for the past 34 years from 1974 to 2007. We created temperature map of 500m resolution using Inverse Distance Weight in application with adiabatic lapse rate per month in linear relation with height and temperature. In the urbanization area, the data analyzed population in comparison with temperature changes by the year. An annual rising rate of temperature was calculated $0.0056^{\circ}C$, and the temperature was increased $2.14^{\circ}C$ from 1974 to 2107. The south climate region in Korea by the Warmth index was expanded to the middle climate region by the latitude after 1990s. A rise of urban area in mean temperature was $0.5-1.2^{\circ}C$, Seoul, metropolitan and cities which were high density of urbanization and industrialization with the population increase between 1980s and 1990s. In case of North Korea, Cities were Pyeongyang, Anju, Gaecheon, Hesan. A rise in cities areas in mean temperature has influence on vegetation, especially secondary growth such as winter buds of pine trees appears built-up area and outskirts in late Autumn. Finally, nowaday we confront diverse natural events over climatical changes, We need a long-term research to survey and analyze an index on the climatical changes to present a systematic approach and solution in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.43-50
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• 2019

Block-chain enjoys technical advantages such as "robust security," owing to the structural characteristic that forgery is impossible, decentralization through sharing the ledger between participants, and the hyper-connectivity connecting Internet of Things, robots, and Artificial Intelligence. As a result, public organizations have highly positive attitudes toward the adoption of technology using block-chain, and the design of university information services is no exception. Universities are also considering the application of block-chain technology to foundations that implement various information services within a university. Through case studies of block-chain applications across various industries, this study designs an empirical model of an integrated information service platform that integrates information systems in a university. A basic road map of university information services is constructed based on block-chain technology, from planning to the actual service design stage. Furthermore, an actual empirical model of an integrated information service in a university is designed based on block-chain by applying this framework.

• Economic and Environmental Geology
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• v.54 no.1
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• pp.117-126
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• 2021

Satellite magnetic observations reflect the magnetic properties of deep crust about the depth of Curie isotherm that is a boundary where the magnetic nature of the rocks is disappeared, showing long wavelength anomalies that are not easily detected in near-surface data from airborne and shipborne surveys. For this reason, they are important not only in the analyses on such as plate reconstruction of tectonic boundaries and deep crustal structures, but in the studies of geothermal distribution in Antarctic and Greenland crust, related to global warming issue. It is a conventional method to compute the spherical harmonic coefficients from global coverage of satellite magnetic observations but it should be noted that inclusion of erroneous data from the equator and the poles where magnetic observations are highly disturbed might mislead the global model of the coefficients. Otherwise, the reduced anomaly model can be obtained with less corruption by choosing the area of interest with proper data processing to the area. In this study, I produced a satellite crustal magnetic anomaly map over East Asia (20° ~ 55°N, 108° ~ 150°E) centered on Korean Peninsula, from CHAMP satellite magnetic measurements about mean altitude of 280 km during the last year of the mission, and compared with the one from global crustal magnetic model (MF7). Also, a comparison was made with long wavelength anomalies from EMAG2 model compiled from all near-surface data over the globe.