• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.589-592
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• 2005

Gravity characteristics and Moho undulations are investigated in the Korean peninsula by using satellite gravity data. According to the development of satellite geodesy, gravity potential models which have high accuracy and resolution were released. Using the EIGEN-CGOIC model based on low orbit satellite data such as CHAMP and GRACE, geoid and gravity anomaly were calculated by spherical harmonic analysis. The study area is located at $123^{\circ}\sim132^{\circ}E, 33^{\circ}\sim43^{\circ}$N including Korea. Free-air anomalies, which show the effect of terrain, have the values between $-37\sim724 mgal. After Bouguer correction, the range of simple Bouguer anomalies is $-221\sim246$ mgal. Complete Bouguer anomalies after terrain correction increase from continent to marine. This phenomenon is related rise of Moho discontinuity. The cut-frequency for extraction of Moho undulation was determined by power spectrum analysis, and then 3D inversion modeling was implemented. The mean, maximum, minimum, and standard deviation of Moho depth undulation are -26, -36, -8, and 4.9 krn, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.2
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• pp.137-150
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• 2010

A meso-urban meteorological model (Urbanized MM5; uMM5) with urban canopy parameterization (UCP) was applied to the high-resolution simulation of meteorological fields in a complex coastal urban area and the assessment of urban impacts. Multi-scale simulations with the uMM5 in the innermost domain (1-km resolution) covering the Busan metropolitan region were performed during a typical sea breeze episode (4~8 August 2006) with detailed fine-resolution inputs (urban morphology, land-use/land-cover sub-grid distribution, and high-quality digital elevation model data sets). An additional simulation using the standard MM5 was also conducted to identify the effects of urban surface properties under urban meteorological conditions. Results showed that the uMM5 reproduced well the urban thermal and dynamic environment and captured well the observed feature of sea breeze. When comparison with simulations of the standard MM5, it was found that the uMM5 better reproduced urban impacts on temperature (especially at nighttime) and urban wind flows: roughness-induced deceleration and UHI (Urban Heat Island)-induced convergence.

• Journal of the Korean earth science society
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• v.21 no.6
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• pp.719-733
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• 2000

Normally, a digital geologic map can be defined as mappable one whose spatial information with geographic information details and geologic database attribute, recorded in a digital format that is readable by computer. It shows fundamentally two different conceptual perspectives: cartography for digital mapping and analysis for geo-data processing. While, as both aspects basically relate to natural entities and their interpretation of complex features fused with multi-sources, digital geo-data mapping or geologic mapping, it should be distinguished from digital mapping in engineering such as UIS(Urban Infomation System) and AM/FM(Automated Mapping/Facilities Management). Furthermore, according to short-cycled development of GIS(Geographic Information System) software architecture based on IT(Information Technology) and wide expansion of GIS applications' fields, the importance of domain analysis and application model is emphasized at digital geologic informatizaion. In this paper, first terms and concepts of geo-data model with general data modeling aspects are addressed, and then case histories for geo-data modeling and several approaches for data modeling in GIS application fields are discussed. Lastly, tentative conceptual geo-data modeling by using UML(Unified Modeling Language) of OO(Object-oriented) concepts with respect to USGS/AASG geo-data mode is attempted. Through this approach, the main benefits for standardization and implementation lineage with conceptual model in consideration to reusability are expected. Conclusively, it is expected that geo-information system and its architecture by UML is the new coming key approach for the GIS application in geo-sciences.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.4
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• pp.197-205
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• 2022

In this paper, a retaining wall system, developed using building Information modeling (BIM), is presented. Based on the information from a literature review, elementary technologies for the system were defined and developed. First, for the elementary technology, BIM libraries were constructed using standards and previous study results to achieve versatility and reusability. Second, methods for determining the quantity take-off (QTO) of a retaining wall were reviewed for an earth-work calculating system. Additionally, inverse distance weighting interpolation was used to generate topography. Finally, four formulas for calculating the QTO were proposed and devised for each element. After its development, the BIM system was analyzed and verified through comparison with a two-dimensional drawing-based QTO. The proposed system is deemed to be practical for determining the QTO of retaining walls and earth works. The contributions and limitations of the research are discussed in this paper.

• Ocean and Polar Research
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• v.34 no.2
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• pp.229-237
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• 2012

Using results from an Earth System model, we investigated change in primary production in the East China Sea, under a global warming scenario. As global warming progresses, the vertical stratification of water becomes stronger, and nutrient supply from the lower part to the upper part is reduced. Consequently, so is the primary production. In addition to the warming trend, there is strong decadal to interdecadal scale variability, and it takes a few decades before the warming trend surpasses natural variability. Thus, it would be very hard to investigate the global warming trend using data of several years' length.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.4
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• pp.304-315
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• 2009

Numerical simulations were carried out to understand the effect of Sea Surface Temperature (SST) spatial distribution on regional circulation. A three-dimensional non-hydrostatic atmospheric model RAMS, version 6.0, was applied to examine the impact of SST forcing on regional circulation. New Generation Sea Surface Temperature (NGSST) data were implemented to RAMS to compare the results of modeling with default SST data. Several numerical experiments have been undertaken to evaluate the effect of SST for initialization. First was the case with NGSST data (Case NG), second was the case with RAMS monthly data (Case RM) and third was the case with seasonally averaged RAMS monthly data (Case RS). Case NG showed accurate spatial distributions of SST but, the results of RM and RS were $3{\sim}4^{\circ}C$ lower than buoy observation data. By analyzing practical sea surface conditions, large difference in horizontal temperature and wind field for each run were revealed. Case RM and Case RS showed similar horizontal and vertical distributions of temperature and wind field but, Case NG estimated the intensity of sea breeze weakly and land breeze strongly. These differences were due to the difference of the temperature gradient caused by different spatial distributions of SST. Diurnal variations of temperature and wind speed for Case NG indicated great agreement with the observation data and statistics such as root mean squared error, index of agreement, regression were also better than Case RM and Case RS.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.1
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• pp.1-15
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• 2008

Chemical Accident Response Information System (CARIS) which has been designed for the efficient emergency response of chemical accidents produces the real-time atmospheric fields through the Regional Atmospheric Modeling System, RAMS. The previous studies were emphasized that improving an initial input data had more effective results in developing prediction ability of atmospheric model. In a continuous effort to improve an initial input data, we replaced the land-use dataset using in the RAMS, which is a high resolution USGS digital data constructed in April, 1993, with the latest land-use data of the Korea Ministry of Environment over the South Korea and simulated atmospheric fields for developing a real-time prediction in dispersion of chemicals. The results showed that the new land-use data was written in a standard RAMS format and shown the modified surface characteristics and the landscape heterogeneity resulting from land-use change. In the results of sensitivity experiment we got the improved atmospheric fields and assured that it will give more reliable real-time atmospheric fields to all users of CARIS for the dispersion forecast in associated with hazardous chemical releases as well as general air pollutants.

• Korean Journal of Remote Sensing
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• v.37 no.5_1
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• pp.1149-1161
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• 2021

With a trend of the utilization of computer vision for satellite images, cloud detection using deep learning also attracts attention recently. In this study, we conducted a U-Net cloud detection modeling using SPARCS (Spatial Procedures for Automated Removal of Cloud and Shadow) Cloud Dataset with the image data augmentation and carried out 10-fold cross-validation for an objective assessment of the model. Asthe result of the blind test for 1800 datasets with 512 by 512 pixels, relatively high performance with the accuracy of 0.821, the precision of 0.847, the recall of 0.821, the F1-score of 0.831, and the IoU (Intersection over Union) of 0.723. Although 14.5% of actual cloud shadows were misclassified as land, and 19.7% of actual clouds were misidentified as land, this can be overcome by increasing the quality and quantity of label datasets. Moreover, a state-of-the-art DeepLab V3+ model and the NAS (Neural Architecture Search) optimization technique can help the cloud detection for CAS500 (Compact Advanced Satellite 500) in South Korea.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.5
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• pp.495-505
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• 2012

Modeling the effects of high-rise buildings on thermo-dynamic conditions and meteorological fields over a coastal urban area was conducted using the modified meso-urban meteorological model (Urbanized MM5; uMM5) with the urban canopy parameterization (UCP) and the high-resolution inputs (urban morphology, land-use/land-cover sub-grid distribution, and high-quality digital elevation model data sets). Sensitivity simulations was performed during a typical sea-breeze episode (4~8 August 2006). Comparison between simulations with real urban morphology and changed urban morphology (i.e. high-rise buildings to low residential houses) showed that high-rise buildings could play an important role in urban heat island and land-sea breeze circulation. The major changes in urban meteorologic conditions are followings: significant increase in daytime temperature nearly by $1.0^{\circ}C$ due to sensible heat flux emitted from high density residential houses, decrease in nighttime temperature nearly by $1.0^{\circ}C$ because of the reduction in the storage heat flux emitted from high-rise buildings, and large increase in wind speed (maximum 2 m $s^{-1}$) during the daytime due to lessen drag-force or increased gradient temperature over coastal area.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.6
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• pp.60-67
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• 2014

Power system fault analysis is commonly based on well-known symmetrical component method, which describes power system elements by positive, negative and zero sequence impedance. The majority of fault in transmission lines is unbalanced fault, such as line-to-ground faults, so that both positive and zero sequence impedance is required for fault analysis. When unbalanced fault occurs, zero sequence current flows through earth and ground wires in overhead transmission systems and through cable sheaths and earth in underground transmission systems. Since zero sequence current distribution between cable sheath and earth is dependent on both sheath bondings and grounding configurations, care must be taken to calculate zero sequence impedance of underground cable transmission lines. In this paper, EMTP-based sequence impedance calculation method was described and applied to 345kV cable transmission systems. Calculation results showed that detailed circuit analysis is desirable to avoid possible errors of sequence impedance calculation resulted from various configuration of cable sheath bonding and grounding in underground cable transmission systems.