• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.1
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• pp.231-238
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• 2019

In this paper, we have studied how to improve the amplifiers efficiency by minimizing the combining loss when several unit power amplifiers are combined to obtain high output power. Specifically, we have developed Ka-band Spatial Combining Amplifier. The fabricated Spatial Combining Amplifier is a Ka-band 20W class SSPA, which uses a 5W class unit amplifier module 8EA designed using a GaN bare die. We also combined The unit amplifier module using 8-way spatial divider and combiner with a hybrid radial structure. The output combining loss of the fabricated spatial coupler is about 0.334dB, which is about 92.6% efficiency. In this paper, we developed a Spatial Combining Amplifier with a maximum saturation output of 10W and a power addition efficiency of over 15%. As a result, we achieved the maximum saturation output of 30W and the power addition efficiency of 19%.

• Journal of Wetlands Research
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• v.14 no.3
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• pp.353-363
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• 2012

In order to operate the hydraulic structures efficiently for reducing flood damage after 4 Major River Restoration Project, it is essential to obtain enough hydraulic information with certain reliability. A coupled modeling system, providing spatial hydraulic information, for multi-dimensional hydraulic models was developed to complement 1-D hydraulic modeling. Developed system can offers spatial and grid unit information as well as line and section unit information from 1-D modeling. It is considered that the coupled modeling system can be used to provide various kinds of hydraulic information for river management and treatment.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.451-456
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• 2003

최근 대부분의 대규모로 추진되는 공공 서비스 목적이나 민간 사용 목적의 공간정보 구축 및 시스템 개발 분야는 실제 데이터베이스 구축이나 기술 개발에 앞서 ISP(정보화 전략계획: Information Strategy Planning)의 수립을 선행하는 경우가 일반적이다. 본 연구는 2000년부터 추진중인 한국전자통신연구원의 4S 기술개발 사업에 선행하여 수행된 4S 연계기술지원 사업의 ISP에 포함된 주요 기술사양을 분석하고, 분석 결과에 대하여 급속히 변화하고 있는 4S 관련 정보 기술동향을 반영함으로서 국내 상황에 적합하고 향후 사업에도 적용이 가능한 확장 모델로 제시하는 것을 목적으로 한다. 기본적으로 4S 기술개발 사업은 GIS-SIIS-GNSS-ITS 등 공간정보를 대상으로 하거나 주요 정보자원으로 이용하는 분야의 연계 기술을 컴포넌트 기반으로 개발하고, 개발된 컴포넌트에 대해서는 컴포넌트의 통합 또는 조립과 시험 검증과정을 통하여 국내외에서 전개되고 있거나 추진중인 다양한 공간정보 관련 사업에 적용 가능하도록 하는 것을 목적으로 하고 있다. 이러한 성과로 4S 기술개발 사 4S 모바일 컴포넌트 개발등과 같은 단위사업을 중심으로 소개되고 있었으나 이러한 단위 사업의 도출과정이나 추진 전략 또는 컴포넌트 연계 또는 재사용 과정등에 대하여는 체계적으로 알려진 경우가 거의 없다. 따라서 본 연구에서는 이러한 부문에 대한 내용을 기술적인 측면에서 분석하고, 이를 보다 확대하여 4S 컴포넌트 기반 단위 사업의 활용 가능성을 발전시킬 수 있는 확장된 아키텍처의 정립 과정으로 수행되고 있다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.346-351
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• 2009

본 연구에서는 화재시 많은 인명피해가 예상되는 공동 주택을 대상으로 단위공간별 화재 성상을 예측하기 위한 실물화재실험을 실시하였다. 구성된 실물화재모델은 비교적 가연물량이 많은 침실과 화재 발생 위험도가 높은 주방을 대상으로 하였으며, 실험 모델에 구성된 단위품목은 일반주택의 가연물을 선조사 한 후 선정하였다. 실험결과 침실의 경우 점화 후 약 5분이 경과되었을 때 플래쉬오버 상태에 이르게 되어 매우 급격한 성장을 보였으며, 최대 열방출율 약 7433.3 kW, 최대 일산화탄소 578.6 ppm, 최대 이산화탄소 1.25ppm, 내부 최대온도 1350$^{\circ}$로 측정 되었다. 특히, 화재 발생 초기에 가연 공간에서 화재의 진화가 이루어지지 않으면 약 3분 내에 인체에 급격한 피해를 줄 수 있는 한계온도 이상으로 화재가 성장하기 때문에 신속한 초기 대응이 필요함을 확인하였다. 이러한 실물화 재실험에서 얻어낸 결과는 향후 화재확대 예측 시뮬레이션 결과와 비교함으로써 각 용도별 공간에서의 화재 확산 예측에 적용 될 수 있을 것이다.

• Spatial Information Research
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• v.23 no.6
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• pp.67-75
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• 2015

Today, because human settlements are concentrated into urban area, urban planning and management technique considering the complexity, diversity, and advanced situations of urban living space is being requested. Especially, to effectively respond to large and diverse climate change driven disaster, it is necessary to develop urban planning technique including land use, infrastructure planning based on disaster vulnerability analysis. However, because current urban climate change disaster vulnerability analysis system(UC-VAS) is using census output area as spatial analysis unit, it is difficult to utilize the analysis results for specific urban planning. Instead, this study applies the grid manner to two study areas. The analysis results show that it can generate more detailed results and it can be used for detailed zoning decision by comparing with areal photos. Furthermore, by describing the limitation of the grid manner and providing professional way to secure additional scientific character and objectivity of the future urban climate change disaster vulnerability analysis system, it is expected that this study contributes to the effectiveness of system management.

• Journal of Navigation and Port Research
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• v.36 no.10
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• pp.873-881
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• 2012

This study is about the case study on the application of modular system to the superstructure of floating architecture in Europe. There are many restraints in the onsite construction of floating architecture. Then, various industrialized construction methods are needed to reduce the portion of the onsite construction in floating architecture. Among the various industrialized construction methods, the modular system can be more suitable for floating architecture. At this background, this study analysed the European cases of the application of modular system and classified the types of applied modular system. As a result, this study could classify the three types of modular system, such as, building unit modular, space unit modular and planning concept modular, and define the characteristics of three types by comparing with each other.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.3
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• pp.127-136
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• 2011

The typical unit infrastructure cost estimation techniques adopted so far in implementing the Korean Impact Fee Zoning have rather been centered around the unilateral simple cost models. The techniques, as such, have frequently been criticized for their lack of flexibility in properly reflecting the regional differences as well as the peculiarities of individual development projects. The Ministry of Land, Transport, and Maritime Affairs (MLTM), in this regard, has recently introduced an enhanced alternative technique. Using the NGIS data, the study probes the viability of the MLTM's new technique by testing the entire estimation process based on the case area in Ansung City. Reflecting the City's characteristics, the study assumes a composite land use plan that accommodates the industrial area in addition to typical residential areas. As an extensive empirical case study, the research has found from the new technique considerable technical merits to overcome the existing shortcomings and summarized its significant policy implications.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.1
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• pp.171-181
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• 2022

The real estate price index plays key roles as quantitative data in real estate market analysis. International organizations including OECD publish the real estate price indexes by country, and the Korea Real Estate Board announces metropolitan-level and municipal-level indexes. However, when the index is set on the smaller spatial unit level than metropolitan and municipal-level, problems occur: missing values. As the spatial scope is narrowed down, there are cases where there are few or no transactions depending on the unit period, which lead index calculation difficult or even impossible. This study suggests a supervised learning-based machine learning model to compensate for missing values that may occur due to no transaction in a specific range and period. The models proposed in our research verify the accuracy of predicting the existing values and missing values.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.2 s.36
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• pp.15-22
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• 2006

Runoff Characteristics has been Analysis Using geomorphologic Instantaneous Unit Hydrograph(GIUH) and geomorphoclimatic unit hydrograph(GCUH) on an ungaged vary small basin about $5km^2$ scale in Kyungbuk gampo area. First, we estimated hydrology Factor using Geographic Information System(GIS) tool and then, calculated the characteristic velocity using the real rainfall-runoff data. It is compared with several velocities derived from GCUH theory and several other concentration time formulae. Kerby and Braby-Williams seems to be more applicable as characteristic velocity formula. Second, We compared the GCUH peak discharge with the probable flood, also compared the unit hydrograph as like the Clark, the Nakayasu and the S.C.S and GCUH with the observed discharge using the real rainfall events. The comparison results showed that GCUH could be applicable on an ungaged vary small basin. We expected that the result can be used as for estimation of a flash flood standard rainfall as well as emergency management plan.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2009.04a
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• pp.215-217
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• 2009

u-GIS는 기존 정적인 공간데이터와 동적인 GeoSensor 데이터를 융합하여 처리하는 시스템을 말한다. 기존 정적인 공간 데이터는 주로 2차원 공간 데이터였으며 최근 유비쿼터스 환경에서는 이를 확장한 3차원 공간 데이터 및 다차원 시공간 데이터의 요구가 급증하고 있다. 최근 국가 차원에서 3차원 공간 데이터를 구축하고 있으며 DBMS가 아닌 파일 단위로 데이터를 저장하고 관리하고 있다. 이 경우, 데이터의 중복 저장, 표준 인터페이스의 부재, 서버 중심의 데이터 제공의 어려움 등의 문제가 발생한다. 따라서 본 연구에서는 3차원 공간데이터를 효과적으로 저장 관리하기 위하여 3차원 공간 DBMS를 연구 개발하였다.