• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.113-116
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• 2008

Pseudo-3D Spatial distribution of spray droplets is investigated by using Dual-mode Phase Doppler Anemometry (DPDA) in order to examine the disintegration and spreading behavior of spray exiting from liquid-thruster injector. Spray injected from nozzle orifice with length-to-diameter ratio $(L/d_o)$ of 1.67 and at the injection pressure of 27.6 bar is aligned to the vertical. Vertical and horizontal mean velocities of droplets, Arithmetic Mean Diameter (AMD), Sauter Mean Diameter (SMD), and volumetric flux decrease as droplets travel from center/upstream toward outer region/downstream of spray.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.213-216
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• 2007

PEMFC의 전기화학적 반응은 촉매, 이오노머, 기공이 만나는 삼상계면에서만 일어나므로, 전극 구조의 최적화가 성능 향상 및 장기안정성 확보에 있어 매우 중요하다. 본 연구에서는 전극 미세구조를 실시간으로 분석하기 위해 임피던스 복소캐패시턴스법을 도입하고자 하였다. 즉, PEMFC의 양극에 질소를 공급하면 0.4 V 부근에서 전기이중층 형성 반응만이 일어나는 것을 확인하였으며, 이때 음극에는 수소를 공급하여 기준전극 및 반대전극으로 사용하였다. 측정된 임피던스를 복소캐패시턴스로 변환하고 허수부를 주파수에 대해 도시하면 피크 형태의 곡선이 얻어지는데, (1) 피크 면적은 전극/전해질의 계면면적, (2) 피크 위치는 이오노머 네트워크에 의한 수소이온 전도 특성, (3) 피크 폭은 다공성 구조의 균일도를 각각 나타내므로, 피팅 없이 직접적인 해석이 가능하다는 장점을 가진다. 반면, 기존의 Nyquist 도시법은 피팅에 의한 분석이 필요하며, 전극층의 불균일한 구조로 인해 단순한 등가회로 구성이 어려운 문제점을 가진다. 최종적으로, MEA 제작 조건 및 운전 조건을 변수로 하여 임피던스를 측정하고 복소캐패시턴스 분석을 수행하여, 퇴화 경로를 규명하고 운전 조건을 최적화하고자 하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1459-1463
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• 2007

도시 유역의 하수관거는 대부분 합류식 하수관거로 되어 있기 때문에 도시하천의 물순환을 모의하기 위해 수량적인 측면이나 수질적인 측면에서 강우시의 합류식 하수관거 월류수 즉, CSOs를 고려한다면 보다 정확한 모의가 가능할 것이다. 목감천 유역은 중 상류 지역의 대부분은 농경 또는 임야로 이용되고 있지만, 하구부에는 밀집된 시가지가 전체유역 면적의 약 35.2 %인 $18.66\;km^2$를 형성하고 있고, 이중 대부분이 합류식 하수관거로 되어 있다. 따라서 목감천 유역을 PCSWMM의 TRANSPORT 블럭내의 flow divider를 이용하여 모형을 구성하여 1996년부터 2005년까지 10년 동안의 연속유출모의를 실시하여 물순환 분석을 하였다. 결과를 보면 10년 평균 강수량은 1537.9 mm이며, 직접유출량 비율은 1,263.0 mm, 침투량은 335.7 mm, 증발량은 415.7 mm이다. 또한 10년 평균 상수량은 909.10 mm, 하수량은 736.3 mm(CSOs 355.0 mm), 하천유입하수량은 170.3 mm, 서남 및 역곡하수처리장 이송량은 211.0 mm이다. 부하량 결과를 살펴보면 발생부하량은 10,108,554 kg/year이며 배출부하량은 834,533 kg/year으로, 이는 곧 점오염원을 의미한다. 유역 총 배출량은 1,575,200 kg/year, 비점오염원은 740,667 kg/year, 하수처리장 이송부하량은 1,220,000 kg/year, 목감천 출구지점에서는 355,200 kg/year(CSOs 62,531 kg/year)임을 알 수 있었다.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.585-593
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• 2013

This study aims to investigate inundation characteristics such as inundated area, inundation depth according to variation in return period of design rainfall and to draw a comparison between the inundation characteristics by adapting design storm using dual-drainage model. Lidar data is used to construct terrain data with $1m{\times}1m$ resolution in Cheongju. The designed storm by return periods(10year, 30year, 50year and 200year) are acquired from Intensity Duration Frequency curve, which are distributed in 5 minutes interval using Huff's method. As a results, the inundation volume is linearly increased, but inundated area is gradually increased in accordance with swell of return period for design storm. On the other hands, as a result of calculating discharge capacity for each points, deficit of discharge capacity is not observed using designed storm of 10 year return period at every points. If the return period is increased up more than 10 years, both the deficit of discharge capacity for each PT and entire study area are enlarged drastically.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.9-18
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• 2021

Constructing the Metropolitan Railway Express (the GTX) may have an impact on consumer confidence and housing sales price located near the planned route. This study looked at how consumers' psychology and housing prices change as the large-scale transport infrastructure plane was planned. Also, it looked at the relationship between consumer sentiment and housing prices to analyze the impact of new transportation facilities inflows. Using a correlation analysis, the relationship between the consumer sentiment index and the actual transaction price of apartments was identified. The impact of GTX on the consumer sentiment index and the actual transaction price of apartments was looked at using the Difference-in-Differences methodology. Our finding shows that the construction plan of a large-scale transportation infrastructure in the metropolitan area affects the sentiment of housing consumption and actual transactions. In a situation where the government is speeding up the construction of a wide-area transportation network such as GTX with the goal of becoming a city where people can commute to downtown Seoul within 30 minutes, policies that can stabilize the housing market in transportation hubs should be suggested.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.115-131
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• 2022

Carbon dioxide (CO₂) emissions from the transportation sector in South Korea accounts for 16.5% of all CO₂ emissions, and road transportation accounts for 96.5% of this sector's emissions in South Korea. Hence, constant research is being carried out on methods to reduce CO₂ emissions from this sector. With the emerging use of smart crossings, attempts to monitor individual vehicles are increasing. Moreover, the potential commercial deployment of autonomous vehicles increases the possibility of obtaining individual vehicle data. As such, CO₂ emission research was conducted at five signalized intersections in the Gangnam District, Seoul, using data such as vehicle type, speed, acceleration, etc., obtained from image detectors located at each intersection. The collected data were then applied to the MOtor Vehicle Emission Simulator (MOVES)-Matrix model-which was developed to obtain second-by-second vehicle activity data and analyze daily CO₂ emissions from the studied intersections. After analyzing two large and three small intersections, the results indicated that 3.1 metric tons of CO₂ were emitted per day at each intersection. This study reveals a new possibility of analyzing CO₂ emissions using actual individual vehicle data using an improved analysis model. This study also emphasizes the importance of more accurate CO₂ emission analyses.

• Proceedings of the Korean Society of Community Living Science Conference
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• 2009.09a
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• pp.104-104
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• 2009

IMF로 인한 경제위기 시기에 도시에서 농촌으로 귀농 가구가 증가하는 현상이 나타났으나 이후 경제가 활성화 되면서 감소하였다. 연도별 귀농가구의 동향은 1998년 6,409가구를 정점으로 1999년에 4,118가구로 감소하였다가 2001년경에는 매년 1000가구 미만의 수준으로 하락하였으나 2008년 말 기준으로 2,218가구에 이르는 비교적 증가하는 추세를 보이고 있다. 한편 지방자치단체 특히 인구 과소화 시군에서는 도시민 유치를 위하여 경쟁적으로 귀농자 지원조례를 제정하여 정착하는 귀농인들을 지원하고 있다. 급기야 2009년 4월에는 중앙정부 차원에서 '귀농귀촌 종합대책'이 발표되었다. 도시에서 농촌으로 이주하는 원인으로는 농업을 직업으로 선택한 결과에 따른 것도 있지만 건강한 생활 및 웰빙 전원생활 영위를 위한 이주 등 그 원인이 다양화 되어 가고 있다. 이주하는 개인의 다양한 동기와 함께 지방자치단체의 지원책 또한 하나의 유인요인이 된다고 할 수 있을 것이다. 귀농귀촌 인구가 증가세를 보이기 시작한 2000년대 중반은 정부와 지방자치단체의 귀농귀촌인 지원대책이 시작된 시기임을 볼 때 그 연계성을 짐작할 수는 있으나 검증된 바는 없다. 그렇지만 귀농인의 입장에서는 선배 귀농인이 많이 거주하거나 지원정책이 잘 되어 있는 곳을 선택하게 될 가능성은 높은 것도 사실이다. 본 연구에서는 귀농인 지원을 위하여 각 지방자치단체가 제정한 지방조례의 내용과 차이점을 분석하고자 한다. 2009년 6월 기준으로 전국 34개 시군에서 지방조례를 제정하였고 이중 13개 시군에서는 시행규칙도 완비하였다. 조례의 주된 내용은 귀농귀촌인에 대한 빈집수리비용, 의료 학자금, 영농정착금, 농지구입자금 등을 지원하는 것으로 되어 있다. 물론 그 지원 규모에 있어서는 다소의 차이가 있지만 귀농귀촌인에 대한 자금의 직접적 지원에 초점이 맞춰져 있다. 귀농자들이 지역사회에 안정적으로 정착하고 정주할 수 있으려면 직접적 자금지원을 벗어나 지역네트워크를 형성하고 지원해 주는 것이 필요할 것으로 사료된다.

• Journal of the Korean Geographical Society
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• v.43 no.1
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• pp.52-70
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• 2008

Using MD Property View database on 15 counties in Maryland in the U.S., this study attempts to explore the estimation process on the housing development capacity under the Maryland's urban growth management policy known as the Smart Growth Initiatives. This study also seeks to draw the implications of the estimated development capacity by individual counties on successful implementation of the urban growth management policy. The finding shows that this region has land for residential use enough to accommodate growth for the next 30 years. However, contrary to the goal of the Smart Growth Initiatives, a majority of development capacity is located not only outside the Priority Funding Area designated by the Smart Growth Initiatives but also at counties that are located far away from the major metropolitan area. In addressing this problem, the state does not need to either abolish or immediately expand the Priority Funding Area. Rather, the state requires local governments to include housing elements in their comprehensive planning, to provide periodic estimates on housing and employment capacity, and to establish and manage database on the location and the capacity of developable land.

• Journal of the Korean Geographical Society
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• v.41 no.2 s.113
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• pp.139-149
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• 2006

Earlier research works focused on the seasonal patterns and bio-geochemical processes in sand dunes, and the satellite data and aerial photographs have been used only as a backdrop or for the multi-temporal delineation of sand dune area. In order to find the optimal way to extract features' characteristics, Gimnyeong sand dune area was selected as a study site. Field works have been carried out three times to collect ground control points and sand samples for laboratory analyses. The texture of sand dune is classified as fine sand, which has been derived from shell fragments. The sand dune penetrated into the island from northwest to southeast direction. An aerial photograph was re-sampled into one-meter resolution and rectified with software including Erdas Imagine and ENVI. Sub-scenes were chosen as samples for sand dune, urban area and rural area. K-group non-parametric analysis had been done for the geometric and spectral values of enclosed texture patches. Urban areas proved to have significant smaller patches than the others.

• Journal of Navigation and Port Research
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• v.36 no.8
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• pp.651-657
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• 2012

In the Busan North port redevelopment project, which is the first large scale port redevelopment project in this country, it adopted the national landscape plan for competitiveness of port city. Furthermore, it includes many efforts on landscape formation in the process of improvement of ocean city image and enhancement of its value, which fits for the situation and characteristics of the original nature, history, and culture resources, together with all facilities, structures, symbols, and eco green belt. Firstly this study attempted to analyze the characteristics of Busan landscape, Busan city design plan(2010), especially coloring plan, together with the case study of landscape color plan for foreign countries. From the basis of this analysis, it was proposed a landscape enhancement strategy in the Busan North port redevelopment project through the coloring plan and it is expected that the result would be used for the basic data for other redevelopment project.