• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.1
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• pp.29-38
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• 2020

Although educational facilities are important considerations from a social equity standpoint, the educational environment generally found in rural areas has been continuously deteriorated due to numerous social problems following birth rate declines and school abolition numbers. The purpose of this study is to evaluate the commuting accessibility changed by the abolition of elementary schools. The village-level accessibility is assessed following physical accessibility criteria based on legally defined commuting distances. Moreover, this study shows the implications of commuting accessibility by school district zones through comparing the minimum commuting distances with real commuting distance. The target area is the Gangwon state, the coverage area in which for schools is the widest in South Korea (44.1 ㎢/school). We evaluated the commuting distances to the nearest elementary school for 992 rural villages and 74 urban villages. Of the 1,066 villages in urban and rural areas evaluated, most of the villages (about 77%) are exposed to commutes to elementary schools were the marginal distance is over 1,000 meters. The annual rate of increase of commuting distance for 1,066 villages in Gangwon state has steadily increased by 2.8%p since 2000, average commuting distance from 2.8 km to 3.6 km. By the designation of the school districts, elementary school students have to go to a faraway school located within administrative district, even though there is a school nearby. It is expected that the results of this study will be made use of as basic data for the establishment of policies such as a reasonable basis for closing schools measurements considering the locally unique environment.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.70-78
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• 2017

The Hwasan wetland vegetation is observed at mountain basin (644~780 m a.s.l.) where had become a potential land for indigenous people since prehistoric period. We phytosociologically investigated old-growth alder (Alnus japonica) forests using the $Z\ddot{u}rich$-Montpellier School's method and analyzed their spatial distribution pattern by actual vegetation map. Species performance was determined by using coverage and r-NCD. Viburnum opulus var. calvescens-Alnus japonica community syntaxonomically belonging to the Alnetea japonicae was first described and composed of three subunits: Salix koreensis subcommunity, typical subcommunity, and Pyrus ussuriensis subcommunity. Present plant community was compared with vicariant syntaxa such as Molinia japonica-Alnus japonica community, Rhamno nipponicae-Alnetum japonicae, and Aceri-Salicetum koreensis. Hwasan's alder forest, an alluvial terrace vegetation type on valley fan in the montane zone, is evaluated as vegetation class [I], which is a sort of benchmark plant community potentially on mountain wetlands in southeastern part of the Korean Peninsula. Simultaneously we suggested an establishment of the national strategy for habitat conservation free from hydrologically radical transform due to military utilization.

• Journal of Communications and Networks
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• v.13 no.6
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• pp.664-677
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• 2011

In order to control interference and improve spectrum efficiency in the femtocell and macrocell overlaid system (FMOS), we propose a joint frequency bandwidth dynamic division, clustering and power control algorithm (JFCPA) for orthogonal-frequency-division-multiple access-based downlink FMOS. The overall system bandwidth is divided into three bands, and the macro-cellular coverage is divided into two areas according to the intensity of the interference from the macro base station to the femtocells, which are dynamically determined by using the JFCPA. A cluster is taken as the unit for frequency reuse among femtocells. We map the problem of clustering to the MAX k-CUT problem with the aim of eliminating the inter-femtocell collision interference, which is solved by a graph-based heuristic algorithm. Frequency bandwidth sharing or splitting between the femtocell tier and the macrocell tier is determined by a step-migration-algorithm-based power control. Simulations conducted to demonstrate the effectiveness of our proposed algorithm showed the frequency-reuse probability of the FMOS reuse band above 97.6% and at least 70% of the frequency bandwidth available for the macrocell tier, which means that the co-tier and the cross-tier interference were effectively controlled. Thus, high spectrum efficiency was achieved. The simulation results also clarified that the planning of frequency resource allocation in FMOS should take into account both the spatial density of femtocells and the interference suffered by them. Statistical results from our simulations also provide guidelines for actual FMOS planning.

• Journal of Korea Water Resources Association
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• v.38 no.10 s.159
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• pp.895-906
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• 2005

The diversity of observed hydrologic data and the development of geographic information system leads significant progress for developing distributed runoff models in the world. One of the typical examples is TOPMODEL, but the spatial coverage of its application Is limited on small headwater basins. The purpose of this study attempts to overcome its limitation and consequently develops a semi-distributed TOPMODEL. The developed model is composed of two components: a watershed runoff component for a lumped representation of hydrologic runoff process on the catchment scale and a kinematic wave type hydraulic channel routing component lot routing the catchment outflows. The application basin is the $2,703km^2$ upper Soyang dam site and several daily and hourly events are selected for model calibrations and verifications. The model parameters are estimated on 1990 daily event. The model performance on correlation coefficient between observed and computed flows are above 0.90 for the verification events. It is concluded that the developed model in this study can be used for flood analysis in large drainage basins.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.2
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• pp.17-24
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• 2014

This paper proposes an automatic extraction method of control point based on Geospatial Web Service. The proposed method consists of 3 steps. 1) The first step is to acquires reference data using the Geospatial Web Service. 2) The second step is to finds candidate control points in reference data and the target image by SURF algorithm. 3) By using RANSAC algorithm, the final step is to filters the correct matching points of candidate control points as final control points. By using the Geospatial Web Service, the proposed method increases operation convenience, and has the more extensible because of following the OGC Standard. The proposed method has been tested for SPOT-1, SPOT-5, IKONOS satellite images and has been used military standard data as reference data. The proposed method yielded a uniform accuracy under RMSE 5 pixel. The experimental results proved the capabilities of continuous improvement in accuracy depending on the resolution of target image, and showed the full potential of the proposed method for military purpose.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.48.1-48.1
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• 2016

Polarimetric study of light scattering from cometary dust particles can provide us opportunity to decipher their characteristics, such as sizes, structures, compositions of dust grains, etc. Herein, we present the results of our polarimetric study of long-period comet, C/2013 US10 (Catalina), in optical and near-infrared wavelengths which appeared at large phase angle (52.7 degrees) around the mid-December, 2015. We performed polarimetric and spectroscopic observations with HONIR, attached to the 1.5-m telescope at Higashi-Hiroshima Observatory, on UT 2015 December 17-18 and also obtained optical imaging data sets by the Ishigakijima Astronomical Observatory (IAO) and Okayama Astrophysical Observatory (OAO) taken between 2014-2015. By measuring the intensities of gas emission lines with respect to dust continuum and considering transmittance of each filter, we estimated that the percentages of gas contamination are approximately 10 percents in $R_C$-band and 3 percents in $I_C$-band. With these results, we derive the degree of linear polarization scattered solely from dust components in the coma. At this presentation, we will compare the phase-angle dependence of the degree of linear polarization with those of previous archive data in a wide coverage of wavelengths from $R_C$-band to $K_S$-band. Finally, we are supposed to discuss the spatial variations in polarization within the coma.

• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.51-59
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• 2013

It is usual to evaluate the performance of the cool roof by measuring in-site rooftop temperature using thermal infra-red camera. The principal advantage of rooftop thermal infrared image acquired in oblique vantage point of super high-rise building as a remote sensor is to provide, in a cost-effective manner, area-wide information required for a scattered rooftop target with different colors, utilizing wide view angle and multi-temporal data coverage. This research idea was formulated by incorporating the concept of traditional remote sensing into rooftop temperature monitoring. Correlations between infrared image of super high-rise building and in-situ data were investigated to compare rooftop surface temperature for a total of four different rooftop locations. The results of the correlations analyses indicate that the rooftop surface temperature by the infrared images of super high-rise building alone could be explained yielding $R^2$ values of 0.951. The visible permanent record of the oblique thermal infra-red image was quite useful in better understanding the nature and extent of rooftop color that occurs in sampling points. This thermal infrared image acquired in oblique vantage point of super high-rise made it possible to identify area wide patterns of rooftop temperature change subject to many different colors, which cannot be acquired by traditional in-site field sampling. The infrared image of super high-rise building breaks down the usual concept of field sampling established as a conventional cool roof performance evaluation technique.

• Journal of Cadastre & Land InformatiX
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• v.50 no.1
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• pp.63-73
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• 2020

The Ministry of Land, Infrastructure and Transport carried out a pilot project for data maintenance in 2011 to ensure the accuracy of cadastral records nationwide, and now trying to reduce the errors such as omission of the cadastral book, inconsistency of land category between cadastral account book and cadastral map, etc. and the boundary between the map boundary, scale, and administrative areas. In this study, we looked at the currents status and problems of the cadastral research, improving the cadastral map, which has been promoted by the government and the cadastral office. In order to revitalize the cadastral map data maintenance project, it is necessary to re-establish the plan for each step for challenging the limitation of current data maintenance, and the master plan for promotion system, and develop manuals to maintain consistency and secure accuracy of cadastral map maintenance, such as "Coverage and Maintenance Guidelines for Cadastral Maps", and secure the national budget for error correction in cadastral map led by government.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.12
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• pp.1388-1398
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• 2012

SAR(Synthetic Aperture Radar) systems can provide images of wide coverage in day, night, and all-weather conditions. However wideband SAR systems are known to be vulnerable to interferences from other devices operating at in-band or adjacent spectrums and this may lead to image corruptions. In this paper, a SAR point target simulator is developed that provides performance analysis on image distortion caused by interferences from other devices. Interference signals are generated based on the experimental data observed from acquired SAR raw data. Simulation results include typical SAR performance measures such as spatial resolution, peak to sidelobe ratio and integrated sidelobe ratio. Finally, SAR target simulations are performed and shown to correspond to the image corruptions found in real SAR missions affected by RF interferences.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.1
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• pp.27-43
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• 2014

The purpose of this research is to assess potential area of mountainous wetland by GIS and AHP (Analytic Hierarchy Process). Mountainous wetland is topographically located at high altitude, so it's difficult to approach for researchers. And, it's difficult to investigate systematically because of the insufficient information of mountainous wetland. Therefore, it's necessary to study on potential area of mountainous wetland for systematic and efficient investigation. This research selected slope, wetting index, land-cover map and soil map as assessment items indicating environmental characteristics of mountainous wetland and established them by GIS DB. And, spatial value of mountainous wetland for each assessment item was drawn by existing investigation data and overlap analysis of mountainous wetland. Based on the numerical results of each assessment item, a survey was conducted and relative importance for each assessment item was decided by AHP. As the result, slope was the highest as 0.550 and ground coverage was the lowest as 0.083. The subject of this research was Yangsan-si and Ulsan of Gyeongnam and an analysis was conducted for mountainous wetland in those research areas. As the result, all of wetland was distributed in the range of potential area. And, field survey and literature search were conducted for the point that the distribution of mountainous wetland is expected. As the result, mountainous wetland was distributed. Therefore, mountainous wetland should be excavated through the results of this research and it should be helpful for effective investigation as providing information necessary to the following studies on mountainous wetland.