• Proceedings of the KSR Conference
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• 2002.05a
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• pp.603-608
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• 2002

Sound absorbing materials are applied to the exposed surfaces of curved subway tunnel for the reduction of curving noise level. Before the treatment, acoustical engineering simulation is performed to predict the noise level reduction for different kinds and amounts of absorbing material. The principle of geometrical acoustics is utilized to Peform the simulation efficiently and accurately. The noise levels of the inside and outside of running car body are measured to find the noise level reduction. The average noise level reduction of 8 ㏈ has been attained. It has been shown that the simulated results are comparable to the measured ones.

• Environmental Engineering Research
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• v.15 no.3
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• pp.167-172
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• 2010

The effects of low impact development (LID) techniques, such as green roofs and porous pavements, on the runoff and pollutant load from an apartment complex were simulated using the Site Evaluation Tool (SET). The study site was the Olympic Village, a preexisting apartment complex in Seoul, South Korea, which has a high percentage of impervious surfaces (approximately 72% of the total area). Using the SET, the effects of replacing parking lots, sidewalks and driveways (37.5% of the total area) having porous pavements and rooftops (14.5% of the total area) with green roofs were simulated. The simulation results indicated that LID techniques reduced the surface runoff, and peak flow and pollutant load, and increased the evapotranspiration and soil infiltration of precipitation. Per unit area, the green roofs were better than the porous pavements at reducing the surface runoff and pollutant loads, while the porous pavements were better than green roofs at enhancing the infiltration to soil. This study showed that LID methods can be useful for urban stormwater management and that the SET is a useful tool for evaluating the effects of LID on urban hydrology and pollutant loads from various land covers.

• Journal of Environmental Science International
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• v.18 no.2
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• pp.169-176
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• 2009

The present study observed temperature in order to identify factors affecting temperature by zoning and to measure the intensity of their impact on temperature. The empirical results of analyzing observed data are as follows. In order to make up for multicollinearity, a problem in multiple regression analysis, and to give more specific explanations, this study conducted factor analysis and obtained desirable data with adequacy and statistical significance. In the correlation matrix, factors decreasing temperature were planted areas, water surfaces and grasslands, and those increasing temperature were bare grounds, paved areas, and building area. According to land cover patterns, commercial areas had the highest temperature lowering effect. Through the rotated component matrix, we found that factors are grouped into those decreasing temperature, those increasing temperature, and those with low significance in increasing or decreasing temperature. In order to solve the problem of multicollinearity in multiple regression analysis, we performed factor analysis between the land use patterns and temperature and confirmed the usability of factor analysis as a new analysis method in urban heat island.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.156-161
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• 2003

Mechanical behavior of rock joints usually can be characterized by small-scale laboratory shear tests due to economical and technical limitations, but their applicability to the behaviour of rock mass has been always questioned by a number of researchers because of scale effect. Though there have been several researches regarding the scale effect, it has been a controversial problem how to apply the result of small-scale laboratory shear test directly to field design from different conclusions among researchers. In order to grasp the trend of scale effect of shear behavior, a series of direct shear tests on replicas of natural rock joint surfaces made of gypsum cement with different size and roughness were conducted and analyzed. Result showed that as the size of the specimen increased, average peak shear displacement increased, but average shear stiffness and average peak dilation angle decreased. As for the dependency of scale on shear strength, the degree of scale effect was dependent on normal stress and roughness of rock joint. For the condition of low normal stress and high roughness, decrease of average peak shear strength with increasing size of joint was evident.

• Journal of Environmental Science International
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• v.33 no.7
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• pp.443-452
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• 2024

The recent increase in impermeable surfaces due to urbanization and the occurrence of concentrated heavy rainfall events caused by climate change have led to an increase in urban flooding. To predict and prepare for flood damage, a convenient and highly accurate simulation of rainfall-runoff based on geospatial information is essential. In this study, the storm water management model (SWMM) was applied to simulate rainfall runoff in the Bangbae-dong area of Seoul, using two sets of topographical data: The conventional topographic digital elevation model (TOPO-DEM) and the proposed shuttle radar topography mission (SRTM)-DEM. To evaluate the applicability of the SRTM-DEM for rainfall-runoff modeling, two DEMs were constructed for the study area, and rainfall-runoff simulations were performed. The construction of the terrain data for the study area generally reflected the topographical characteristics of the area. Quantitative evaluation of the rainfall-runoff simulation results indicated that the outcomes were similar to those obtained using the existing TOPO-DEM. Based on the results of this study, we propose the use of SRTM-DEM, a more convenient terrain data, in rainfall-runoff studies, rather than asserting the superiority of a specific geospatial data.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.190-199
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• 2020

Globally, more super-tall buildings tend to be constructed competitively in the social and economic foundations. In the circumstance, this study is aimed at establishing a paradigm of super-tall buildings in terms of their various forms. Symbolizing a city or state, super-tall buildings not only are used as resources of tourism, but play an important role as a characteristic landmark. Therefore, it is necessary to find a curved form for a futuristic perspective. The purpose of this study is to infer the convergence relativity of curved forms among complex and diverse unstructured construction forms. This study used as subjects 50 super-tall buildings among the ranking data selected Council on Tall Buildings and Urban Habitat (CTBUH) in order for the basis of constructability related to actual design, rather than the way of recognizing a formative type, in the classification of curved forms into regularized surfaces, developable surfaces, and double-curved surfaces. The results of this study are presented as follows. This classification can be used as a fundamental material which is reasonably involved in the design process pursuing diverse curved surfaces in terms of design of tall buildings.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.516-516
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• 2002

With the wide usage of LiDAR data and high-resolution satellite image, 3D modeling of buildings in urban areas has become an important research topic in the photogrammetry and computer vision field for many years. However the previous modeling has its limitations of merely texturing the image to the DSM surface of the study area and does not represent the relief of building surfaces. This study is focused on presenting a system of realistic 3D building modeling from consecutive stereo image sequences using digital camera. Generally when acquiring images through camera, various parameters such as zooming, focus, and attitude are necessary to extract accurate results, which in certain cases, some parameters have to be rectified. It is, however, not always possible or practical to precisely estimate or rectify the information of camera positions or attitudes. In this research, we constructed the collinearity condition of stereo images through extracting the distinctive points from stereo image sequence. In addition, we executed image matching with Graph Cut method, which has a very high accuracy. This system successfully performed the realistic modeling of building with a good visual quality. From the study, we concluded that 3D building modeling of city area could be acquired more realistically.

• Membrane and Water Treatment
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• v.10 no.1
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• pp.13-17
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• 2019

This study was conducted to analyse the application of pollutant build-up model on various urban landuses and to characterize pollutant build-up on urban areas as a source of stormwater runoff pollution. The monitored data from impervious surfaces in urban areas such as commercial (8 sites), industrial (10 sites), road (8 sites), residential (10 sites), recreational (5 sites) from 2008 to 2016 were used for the analysis of pollutant build-up model. Based on the results, the average runoff coefficients vary from 0.35 to 0.61. In all landuses except recreational landuse, the runoff coefficient is 0.5 or more, which is the highest in the commercial area. Commercial landuse where pollutants occur at the highest EMC in all landuse, and it is considered that NPS management is necessary compared with other landuses. The maximum build-up load for organic matter (BOD) was highest in the commercial area ($4.59g/m^2$), and for particular matter (TSS) in the road area ($5.90g/m^2$) while for nutrient (TN and TP) in the residential area ($0.40g/m^2$, $0.14g/m^2$). The rate constants ranged from 0.1 to 1.3 1/day depending on landuse and pollutant parameters, which means that pollutant accumulation occurs between 1 and 10 days during dry day. It is clear that these build-up curves can generally be classified based on landuse. Antecedent dry day (ADD) is a suitable and reasonable variable for developing pollutant build-up functions. The pollutant build-up curves for different landuse shows that these build-up curves can be generally categorized based on landuse.

• Journal of Korean Society on Water Environment
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• v.38 no.4
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• pp.177-189
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• 2022

Nature-based Solutions (NbS) are defined as practical and technical approaches to restoring functioning ecosystems and biodiversity as a means to address socio-environmental challenges and provide human-nature co-benefits. This study reviews NbS-related literature to identify its key characteristics, techniques, and challenges for its application in climate-adaptive water management. The review finds that NbS has been commonly used as an umbrella term incorporating a wide range of existing ecosystem-based approaches such as low-impact development (LID), best management practices (BMP), forest landscape restoration (FLR), and blue-green infrastructure (BGI), rather than being a uniquely-situated practice. Its technical form and operation can vary significantly depending on the spatial scale (small versus large), objective (mitigation, adaptation, naturalization), and problem (water supply, quality, flooding). Commonly cited techniques include green spaces, permeable surfaces, wetlands, infiltration ponds, and riparian buffers in urban sites, while afforestation, floodplain restoration, and reed beds appear common in non- and less-urban settings. There is a greater lack of operational clarity for large-scale NbS than for small-scale NbS in urban areas. NbS can be a powerful tool that enables an integrated and coordinated action embracing not only water management, but also microclimate moderation, ecosystem conservation, and emissions reduction. This study points out the importance of developing decision-making guidelines that can inform practitioners of the selection, operation, and evaluation of NbS for specific sites. The absence of this framework is one of the obstacles to mainstreaming NbS for water management. More case studies are needed for empirical assessment of NbS.

• Journal of The Geomorphological Association of Korea
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• v.26 no.3
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• pp.69-85
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• 2019

Humans have been important driver to reconfigure the terrestrial surface of the Earth by altering its morphology and processes. The effect of human activities on the physical landscape, however, shows substantially uneven geographical patterns. Most of anthrogemorphoogical studies regarding human-induced denudation have focused on areas with a long history of human modifications such as humid landscapes, so the hypothesis is naturally a great human impact on landscapes. The effect of human activities on dryland Earth surfaces are far less commonly studied, although erosion is one of major concerns in arid and semi-arid region regarding land and water quality degradation. The urban metropolis of Phoenix, Arizona, USA provides an opportunity to explore the impact of the Anthropocene. The Phoenix metropolitan area rests on classic desert landforms, such as extensive pediments, alluvial fans and sand sheets. Human activities including cattle crazing, wildfire resulting from introduced grass species by human, and recent urbanization processes have impacted these classic desert landforms and altered geomorphic processes. The purpose of this paper, therefore, rests in examining Anthropocene in the geomorphology of the north-central Sonoran Desert. The objectives of this paper are: i) to understand the impact of the Anthropocene on the geomorphological processes and forms through field observations; ii) to quantify the magnitude of human impacts on landscape using a published two-decade long record of erosion dataset and natural background erosion dataset in submitted manuscript at the sprawling edge of the Phoenix metropolitan region; iii) to examine how geomorphic outcome can affect the sustainability of cities through the estimation of sediment yield under the condition of urban sprawl.