• Journal of Positioning, Navigation, and Timing
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• v.9 no.1
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• pp.1-6
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• 2020

The Chinese BeiDou Satellite Navigation System consists of three kinds of constellations: the geostationary Earth orbit (GEO), the inclined geosynchronous satellite orbit (IGSO), and the medium Earth orbit (MEO). The BeiDou has expanded its service coverage from regional to global. Recently, the BeiDou has been widely used in ionospheric total electron content (TEC) research. In this study, we analyzed the BeiDou signals for ionospheric TEC monitoring over Jeju Island in South Korea. The BeiDou GEO TEC showed a clear pattern of diurnal variations. In addition, we compared the TEC values from the BeiDou GEO, the BeiDou IGSO, GPS, and International GNSS Service (IGS) Global Ionosphere Maps (GIM). There was a difference of about 5 TEC units between the BeiDou GEO and the IGS GIM. This may be due to the altitude difference between the different navigation satellites.

• Journal of Environmental Science International
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• v.27 no.3
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• pp.179-193
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• 2018

Nitrogen budgets in Sihwa-ho in 2010 were estimated using a mass balance approach. Major nitrogen fluxes sources can be divided into three sections: cities, agricultural area, and forest. Surplus nitrogen 2,030~2,214 ton/yr (2,123 ton/yr in average) was discharged to Sihwa Lake. 20% of the surplus nitrogen is removed from the wetland and 60% is removed tidal flats. Therefore net nitrogen discharge from Sihwa basin is estimated to be 650~708 ton/yr (679 ton/yr in average). Wet and dry nitrogen deposition and load from non-point sources ware estimated to be 97 ton/yr and 69 ton/yr, deposition is using CAMx model. So estimated total nitrogen discharge into Sihwa-ho was 817~875 ton/yr (846 ton/yr in average). The atmospheric load explains 11.1~11.9% (11.5% in average) of the total nitrogen load Sihwa-ho.

• Journal of Korean Society for Geospatial Information Science
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• v.1 no.2 s.2
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• pp.22-41
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• 1993

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.191-196
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• 2002

From this year, KIGAM, one of Korean government-supported research institutes, has started new national program for digital geologic/natural resources infrastructure building. The goal of this program is to prepare digitally oriented infrastructure for practical digital database building, management, and public services of numerous types of paper maps related to geo-scientific resources or geologic thematic map sets: hydro-geologic map, applied geologic map, geo-chemical map, airborne radiometric/magnetic map, coal geologic map and off-shelf bathymetry map and so forth. As for digital infrastructure, several research issues in this topic are composed of: ISP (Information Strategy Planning), geo-framework modeling of each map set, pilot database building, cyber geo-mineral directory service system, and web based geologic information retrieval system upgrade which services Korean digital geologic maps scaled 1:50K. In this study, UML (Unified Modeling Language)-based data modeling of geo-data sets by and in KIGAM, among them, is mainly discussed, and its results are also presented in the viewpoint of digital geo-modeling ISP. It is expected this model is further progressed with the purpose of being a guidance or framework modeling for geologic thematic mapping and practical database building, as well as other types of national thematic map database building.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1164-1168
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• 2005

최근에 홍수범람도나 재해지도를 작성하는 등 하천에 대한 범람해석의 연구가 활발히 진행되고 있는 실정이다. 1차원 하천범람해석은 홍수위를 산정하고 지리정보시스템을 이용하여 범람구역을 작성하는 경우가 일반적으로 적용되고 있다. 본 연구에서는 ArcView를 이용하여 광양항 유역특성에 대해 조사하고 홍수범람을 예측하기 위해 HEC-GeoRAS 및 HEC-RAS를 이용하여 홍수범람지역 및 수리특성을 분석하였다. 광양항 지역특성인 조석 및 다수의 유입지류가 존재하는 조건을 고려하기 위해 HEC-RAS 부정류 모의을 이용하여 수위를 분석하였다. 또한 기존 수치지도와 현 상태를 재측량한 성과를 합성하여 지형자료를 추출하여 지형적 오차를 방지하였다. 본 연구에서 1차원 하천 부정류 모의 결과는 각 측점에 대해 시간대별로 수리특성을 계산하였으며 최대수위는 EL. 3.05m로 산정되었다. 또한 유속과 유량이 음(-)의 값을 갖는 경우에 흐름 방향이 역전되므로, 측점 4040.969에서 흐름이 분기되는 것으로 판단되었다. 또한 대상구간에 대한 홍수범람해석을 HEC-GeoRAS 후처리과정을 이용하여 각 측점에 따라 시간별대로 산정하였다. 일부 하천구간 및 저지대의 경우에 침수되는 것으로 표시되었으며, 이것은 1차원 범람해석상의 한계로 판단되었다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2002.04a
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• pp.17-24
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• 2002

Mechanization is the characteristic of the industrial era and computerization is the characteristic of the Information Era. Now we are facing on the transition from Industrial Era to information Era. Established the National Geo-spatial Data Infrastructures is the fundamental base for information society and is one part of the national basic economic development plan. From 1980's China started his successful transition from traditional methods to high-tech based mapping. China has laid out a high accuracy national GPS (global Positioning System) network, and completed the geographic information databases for scale of 1:1million and 1:250,000. Now it is working on the databases for scales of 1:50,000 and 1:10,000, the world highest level. The massive national programmed has been dubbed "Digital China," since it involves massive quantities of digitized geographical information. Simultaneity, GIS technology and the geo-spatial data have been used widely in electronic government affair, environmental protection, disaster control, ITS and etc. The users have realized the benefits more and more widely. Internet is an efficient way to distribute the geo-information, the State Bureau of Surveying and Mapping has give great effort to settle down the rules and standards to establish the clearing house. Some National Geo-standards have issued, and some of them are on the way. The GIS software is another important factor in the GIS industry. Chinese government working-out some good policy to supports the GIS software developer to have their own copyright. This paper is based on the above to introduce the status and development of Geomatics in China. in China.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.2
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• pp.107-116
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• 2012

We investigated the accuracy in three dimensional geo-positioning derived by four high resolution satellite images acquired by two different sensors using the vendor-provided rational polynomial coefficients(RPC) based block adjustment in this research. We used two in-track stereo pairs of GeoEye-1 and WorldView-2 satellite and DGPS surveying data. In this experiment, we analyzed accuracies of RPC block adjustment models of two kinds of homogeneous stereo pairs, four kinds of heterogeneous stereo pairs, three 3 triplet image pairs, and one quadruplet image pair separately. The result shows that the accuracies of the models are nearly same. The accuracy without any GCPs reaches about CEP(90) 2.3m and LEP(90) 2.5m and the accuracy with single GCP is about CEP(90) 0.3m and LEP(90) 0.5m.

• Journal of Cadastre & Land InformatiX
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• v.46 no.2
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• pp.123-135
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• 2016

Recently, geo-based application services such as location-based commerce or personal navigation are recognized as a kind of common tool on smart-phone, and demands with respect to advanced functions of online map editing linked to value-added contents are increasing. However, the disabled people have severe difficulties to equally use those geo-based services, compared to the normal people's uses. Of course, this situation is almost same to other application fields besides geo-based applications. Web accessibility basically means necessary guideline handling web-based contents for equal uses of web services for all people. W3C has developed and distributed a generalized web content accessibility guideline, and Korean web content accessibility guideline version 2.1 referred it. As well, there is a certificate system operated by public agencies. In spite of this situation, geo-based application field is globally on the very early stage for web accessibility. This work first summarized the concept of web accessibility and Korean guideline, and then presented some practical schemes for the further geo-based applications, focused on web visualization of geo-based contents among numerous implementable application services.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.3
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• pp.1-12
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• 2009

This study aims to analyze the existing problem of geo-spatial information maintenance and then, show maintenance strategies suitable for new integrated environments. We look for AS-IS which is provider-centered, top-down, and also drive implications from analyzing oversea best practice. For analyzing of geo-spatial maintenance pattern, we polled about 20 local governments and private enterprise to find out AS-IS of geo-spatial information and result in maintenance pattern and component. From this, we suggest 4 kinds of strategies. This study shows the strategy not only which decide the question about the problem of existing geo-spatial maintenance but which find a way of combining and utilizing all geo-spatial information which is 8 criteria basic geographical information. This is a win-win program of all organization which produce, construct, make full use of national geo-spatial information.

• Journal of the Korean Geotechnical Society
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• v.23 no.11
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• pp.77-85
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• 2007

This paper investigates the mechanical characteristics of composite geo-material which was developed to reuse both dredged soils and bottom ash. The composite geo-material used in this experiment consists of dredged soil taken from the construction site of Busan New Port, cement, air foam and bottom ash. Bottom ash is a by-product generated at the Samcheonpo thermal power plant. Several series of laboratory tests were performed to investigate behavior characteristics of composite gee-material, in particular the reinforcing effect by mixing bottom ash. The experimental results of composite geo-material indicated that the stress-strain relationship and the unconfined compressive strength are strongly influenced by mixing conditions. Especially it was observed that the compressive strength of composite geo-material increased with an increase in bottom ash content due to reinforcing effect by the bottom ash. Compressive strength of composite geo-material increased with the increase in curing time. The 28-day strength of composite geo-material is $1.7{\sim}1.8$ times higher than the 7-day strength. The moist unit weight strongly depended on air-foam content as well as bottom ash content added to the composite goo-material. In composite geo-material, secant modulus ($E_{50}$) also increased as its compressive strength increased due to the inclusion of bottom ash.