• Journal of Radiation Protection and Research
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• 제45권3호
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• pp.101-107
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• 2020

Background: An important lesson learned from the Fukushima accident is that the transition to the mid- and long-term phases from the emergency-response phase requires less than a year, which is not very long. It is necessary to know how much radioactive material has been deposited in an urban area to establish mid- and long-term countermeasures after a radioactive accident. Therefore, an urban deposition model that can indicate the site-specific characteristics must be developed. Materials and Methods: In this study, the generalized urban deposition velocity and the subsequent variation in radionuclide contamination were estimated based on the characteristics of the Korean urban environment. Furthermore, the application of the obtained generalized deposition velocity in a hypothetical scenario was investigated. Results and Discussion: The generalized deposition velocities of ¹³⁷Cs, ¹⁰⁶Ru, and ¹³¹I for each residence type were obtained using three-dimensional (3D) modeling. For all residence types, the deposition velocities of ¹³¹I are greater than those of ¹⁰⁶Ru and ¹³⁷Cs. In addition, we calculated the generalized deposition velocities for each residential types. Iodine was the most deposited nuclide during initial deposition. However, the concentration of iodine in urban environment drastically decreases owing to its relatively shorter half-life than ¹⁰⁶Ru and ¹³⁷Cs. Furthermore, the amount of radioactive material deposited in nonresidential areas, especially in parks and schools, is more than that deposited in residential areas. Conclusion: In this study, the generalized urban deposition velocities and the subsequent deposition changes were estimated for the Korean urban environment. The 3D modeling was performed for each type of urban residential area, and the average deposition velocity was obtained and applied to a hypothetical accident. Based on the estimated deposition velocities, the decision-making systems can be improved for responding to radioactive contamination in urban areas. Furthermore, this study can be useful to predict the radiological dose in case of large-scale urban contamination and can support decision-making for long-term measurement after nuclear accident.

• 대한원격탐사학회지
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• 제23권1호
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• pp.43-53
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• 2007

In this study, two standard specifications such as GML (Geography Markup Language) from OGC (Open Geo-spatial Consortium, Inc.) and X3D (extensible 3D) from Web3D consortium were dealt with for a web-based 3D urban application without using commercialized tools. In the first step of this study, DEM (Digital Elevation Model) and 3D GIS data sets were converted to GML structure with attribute schema. Then, these GML elements were projected onto a common coordinate system, and they were converted to the X3D format for visualization on web browser. In this work, a 3D urban data model, as a simple framework model, is extended to a framework model having further detailed information, depending upon application levels. Conclusively, this study is to demonstrate for practical uses of GML and X3D in 3D urban application and this approach can be applied to other application domains regarding system integrators and data sharing communities on distributed environments.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.159-162
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• 2005

도시지역에의 내수범람은 주로 우수관로 배수체계의 통수능력 부족으로 발생된다. 따라서 지금까지의 도시침수에 대한 국내 연구가 우수관로해석에 국한되어왔다. 하지만 우수관로시스템 해석을 통해서 배수능이 부족한 관거를 찾는 것만으로 침수방지대책을 세우는 것은 매우 근사적이고 비합리적인 대안을 제시할 수밖에 없는 실정이다. 본 연구에서는 도시침수양상에 대한 정확하고 합리적인 해를 도출하기 위하여 지표류 해석을 통한 침수해석의 필요성을 제시하였고, 2001년 7월 서울지역의 집중호우 사상에 대한 적용결과로 해석 결과를 검증하였다. 본 연구의 결과는 도시 홍수 예경보와 침수범람도 작성 등의 도시치수 및 방재계획 수립에 실제적으로 응용될 수 있을 것으로 기대된다.

• 한국시스템다이내믹스연구
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• 제4권2호
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• pp.71-94
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• 2003

The purpose of this dissertation is to build a development density control model and estimate optimum developmental density level for a sustainable urban growth management. To develop the model, system dynamics modeling approach was used. The model was developed to analyze how urban growth, transition, and decay occur depending on the interaction among population, houses, industry structure, land and urban infrastructure such as road, water supply, and sewage treatment facilities. The model was applied to Anyang city to estimate optimum density level. Extensive computer simulation was conducted to find out the maximum numbers of population, industry structure, houses, and cars that can be adequately sustained with the current Anyang city's infrastructure capacity. The computer simulation result shows that the city is overpopulated by some 90,000 people. It nab analyzed that 20％ increase of existing capacity of urban infrastructure is necessary to support current population of Anyang city. To reduce the population to the adequate level whereby the current urban infrastructure can sustain, the current city regulation on floor area ratio needs be strengthened at least 20％ to 35%.

• 한국BIM학회 논문집
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• 제8권3호
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• pp.12-19
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• 2018

The research aims to find implications of machine learning and urban big data as a way to construct the flexible transportation network system of smart city by responding the urban context changes. This research deals with a problem that existing a bus headway model is difficult to respond urban situations in real-time. Therefore, utilizing the urban big data and machine learning prototyping tool in weathers, traffics, and bus statues, this research presents a flexible headway model to predict bus delay and analyze the result. The prototyping model is composed by real-time data of buses. The data is gathered through public data portals and real time Application Program Interface (API) by the government. These data are fundamental resources to organize interval pattern models of bus operations as traffic environment factors (road speeds, station conditions, weathers, and bus information of operating in real-time). The prototyping model is implemented by the machine learning tool (RapidMiner Studio) and conducted several tests for bus delays prediction according to specific circumstances. As a result, possibilities of transportation system are discussed for promoting the urban efficiency and the citizens' convenience by responding to urban conditions.

• Environmental Engineering Research
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• 제16권3호
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• pp.113-119
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• 2011

This study traces the origin, evolution, and current state-of-the-art of engineering-oriented water-quality management and modeling. Three attributes of polluted water underlie human concerns for water quality: rubbish (aesthetic impairment), stink (ecosystem impairment), and death (public health impairment). The historical roots of both modern environmental engineering and water-quality modeling are traced to the late nineteenth and early twentieth centuries when European and American engineers worked to control and manage urban wastewater. The subsequent evolution of water-quality modeling can be divided into four stages related to dissolved oxygen (1925-1960), computerization (1960-1970), eutrophication (1970-1977) and toxic substances (1977-1990). Current efforts to integrate these stages into unified holistic frameworks are described. The role of water-quality management and modeling for developing economies is outlined.

• Wind and Structures
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• 제26권1호
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• pp.45-56
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• 2018

Wind damage of urban trees arises to be a serious issue especially in the typhoon-prone areas. As a family of tree species widely-planted in Southeast China, the structural behaviors of Plane tree is investigated. In order to accommodate the complexities of tree morphology, a fractal theory based finite element modeling method is proposed. On-site measurement of Plane trees is performed for physical definition of structural parameters. It is revealed that modal frequencies of Plane trees distribute in a manner of grouped dense-frequencies; bending is the main mode of structural failure. In conjunction with the probability density evolution method, the fragility assessment of urban trees subjected to wind excitations is then proceeded. Numerical results indicate that small-size segments such as secondary branches feature a relatively higher failure risk in a low wind level, and a relatively lower failure risk in a high wind level owing to windward shrinks. Besides, the trunk of Plane tree is the segment most likely to be damaged than other segments in case of high winds. The failure position tends to occur at the connection between trunk and primary branches, where the logical protections and reinforcement measures can be implemented for mitigating the wind damage.

• 농촌계획
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• 제15권2호
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• pp.97-110
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• 2009

The objective of this research was to develop a rural settlement demand model to analyze the determinants of settlement demand of urban residents. The point aimed at from model development was deriving stated preference of potential consumers towards rural settlement through setting a hypothetical market, and using settlement subsidy as a surrogate variable for price in the demand model. The adequate demand model deducted from hypothetical market data was derived from the basis of Hanemann's utility difference theory. In the rural settlement demand model, willingness to accept was expressed by a function of settlement subsidy. Data utilized in the analysis was collected from surveys of households nationwide. According to inferred results of the demand model, settlement subsidy had a significant influence on increasing demand for rural settlement. A significant common element was found among variables affecting demand increase through demand curve shift. The majority group of those with high rural settlement demand sought agricultural activity as their main motive, due to harsh urban environments aggravated by unstable job market conditions. Subsequently, restriction of income opportunities in rural areas does not produce an entrance barrier for potential rural settlers. Moreover, this argument could be supported by the common trend of those with high rural settlement demand generally tending to have low incomes. Due to such characteristics of concerned groups of rural settlement demand, they tended to react susceptibly to the subsidy provided by the government and local autonomous entities.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.647-650
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• 2006

Compact Airborne Spectrographic Imager (CASI) hyperspectral imagery was acquired over the Little Miami River Watershed (1756 square miles) in Ohio, U.S.A., which is one of the largest hyperspectral image acquisition. For the development of a 4m-resolution land cover dataset, a hierarchical approach was employed using two different classification algorithms: 'Image Object Segmentation' for level-1 and 'Spectral Angle Mapper' for level-2. This classification scheme was developed to overcome the spectral inseparability of urban and rural features and to deal with radiometric distortions due to cross-track illumination. The land cover class members were lentic, lotic, forest, corn, soybean, wheat, dry herbaceous, grass, urban barren, rural barren, urban/built, and unclassified. The final phase of processing was completed after an extensive Quality Assurance and Quality Control (QA/QC) phase. With respect to the eleven land cover class members, the overall accuracy with a total of 902 reference points was 83.9% at 4m resolution. The dataset is available for public research, and applications of this product will represent an improvement over more commonly utilized data of coarser spatial resolution such as National Land Cover Data (NLCD).

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.98-101
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• 2006

In general, stereo images are widely used to remote sensing or photogrametric applications for the purpose of image understanding and feature extraction or cognition. However, the most cases of these stereo-based application deal with 2-D satellite images or the airborne photos so that its main targets are generation of small-scaled or large-scaled DEM(Digital Elevation Model) or DSM(Digital Surface Model), in the 2.5-D. Contrast to these previous approaches, the scope of this study is to investigate 3-D stereo processing and visualization of true geo-referenced 3-D features based on anaglyph technique, and the aim is at the prototype development for stereo visualization system of complex typed 3-D GIS features. As for complex typed 3-D features, the various kinds of urban landscape components are taken into account with their geometric characteristics and attributes. The main functions in this prototype are composed of 3-D feature authoring and modeling along with database schema, stereo matching, and volumetric visualization. Using these functions, several technical aspects for migration into actual 3-D GIS application are provided with experiment results. It is concluded that this result will contribute to more specialized and realistic applications by linking 3-D graphics with geo-spatial information.