• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.6
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• pp.410-418
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• 2017

The stability of low-crested structure (LCS) and overtopping discharge over a seawall behind the LCS are influenced by the water level behind the structure. Hence, the experimental results can be distorted unless the increase of water level is known when two-dimensional experiment is carried out. In order to estimate increase of the mean water level behind the low-crested structure, this study applied a hybrid technique that combined results of two-dimensional model test and hydrodynamic numerical modeling based on the relationship between the water level and discharge. By using this technique, the mean water level increase and flow field can be obtained almost at the same time, which resolved the above problem considerably. In addition, this method can provide an approximate information about the outflow velocity from the openings of the structure, which is helpful for selecting appropriate planar configuration of the low-crested structure.

• Journal of Soil and Groundwater Environment
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• v.20 no.7
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• pp.61-69
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• 2015

This study was performed to provide fundamental data to establish the new soil pollution standards and the soil contamination management plans in a rational manner. The distribution characteristics of new soil contaminants such as barium (Ba) and chromium (Cr) in soils (n=140) were investigated in relation to land-use classification and geological features. Also, the sequential extraction test was conducted to evaluate fate and mobility of new soil contaminants. The soil samples taken from 140 sites were analyzed to survey distribution levels of selected new soil contaminants. The average concentration and range for hazardous metals (Ba, Cr) were Ba 128.946 (26.757~489.587) mg/kg, Cr 30.121 (2.579~132.783) mg/kg. Based on land use classification, the highest Ba concentration was found in factory soils, followed by dry field and park soils, while Cr concentration was highest in rice paddy soils, followed by dry field and factory soils. Within 10 geological units investigated the highest Ba and Cr concentrations were observed in the soils from Okcheon group and metamorphic rocks, respectively. The BCR (European Community Bureau of Reference) sequential extraction was conducted to identify chemical distributional existence of 2 elements of soils from each geological unit. Ba in soils is mainly assumed to exists as reducible form (such as BaSO₄, BaCO₃) and Cr in soils mainly is assumed to exist as residual form (such as Cr₂O₃, Cr_xFe_1-x(OH)₃(x < 1)).

• Journal of the Korean Association of Geographic Information Studies
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• v.3 no.2
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• pp.61-72
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• 2000

The maturation of the Web technology has reshaped the ways in which data are accessed, disseminated, and shared. Thanks to its popularity along with the advance of spatial information technology, four major changes have been further made in traditional geographic information systems (GIS) in relation to access to data, distribution of data, access to GIS functionality, and visualization of multimedia data. Although access to and dissemination of spatial data over the Web has in recent years been addressed in the literature, little research effort has addressed the issue of access to and processing of GIS analysis functions over the Web. This research explores the potential use of Web-based GIS in improving accessibility to distributed spatial data and spatial modeling tools. A prototype Web-based GIS developed in this study focuses on Web-based location-allocation modeling for spatial decision support, and employs a hybrid approach that uses the Arc/Info software as a GIS server and CGM viewer as a client-side plug-in. This research shows that Web-based GIS is a useful vehicle in conducting spatial modeling in the particular user community. In addition, this study represents the possibility of Web-based GIS in developing open spatial decision supporting systems.

• Journal of the Korea Computer Graphics Society
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• v.14 no.4
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• pp.7-18
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• 2008

To realistically produce fluids such as smoke for the visual effects in the films or animations, we need two main processes: a physics-based modeling of smoke and a rendering of smoke simulation data, based on light transport theory. In the computer graphics community, the physics-based fluids simulation is generally adopted for smoke modeling. Recently, the interest of the particle-based Lagrangian simulation methods is increasing due to the advantages at simulation time, instead of the grid-based Eulerian simulation methods which was widely used. As a result, because the smoke rendering technique depends heavily on the modeling method, the research for rendering of the particle-based smoke data still remains challenging while the research for rendering of the grid-based smoke data is actively in progress. This paper focuses on realistic rendering technique for the smoke particles produced by Lagrangian simulation method. This paper introduces a technique which is called particle map, that is the expansion and modification of photon mapping technique for the particle data. And then, this paper suggests the novel particle map technique and shows the differences and improvements, compared to previous work. In addition, this paper presents irradiance map technique which is the pre-calculation of the multiple scattering term in the volume rendering equation to enhance efficiency at rendering time.

• Journal of the Korea Institute of Building Construction
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• v.19 no.6
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• pp.539-547
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• 2019

Recently, the international community signed a climate change agreement to prevent global warming. Yet currently, the fossil fuels have been widely used in to supply building energy for cooling and heating. The Green Building certification (G-SEED), an energy efficiency rating for new or existing buildings requires that buildings meet certain conditions. Insulation is used as a building material to reduce the energy supply to buildings and to improve the thermal insulation, and it accounts for more than 90% of the total heat resistance provided by the building surface components that meet the energy-saving design standards of new buildings. In this investigation, a performance evaluation study was conducted through an experimental study by directly extracting the foam polystyrene insulation on-site during the remodeling of a building that was in the range of 22~38 years old. Through tests, it was found that the thermal conductivity of the extrusion method insulation (XPS) was reduced by 48% and the compressive strength of XPS decreased by 36% compared to KS M 3808, which is the initial quality standard. For bead method insulation (EPS) with a thickness of 50mm, the thermal conductivity, the compressive strength, and flexural failure load were similar to the initial quality standard. Therefore, in the calculation of the primary energy requirement per unit area per year, the performance of bead method insulation can be estimated simply by considering the thickness of the insulation, while a correction factor that considers its performance deterioration should be applied when extrusion method insulation is used.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.5
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• pp.535-546
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• 2020

Land cover maps are derived from satellite and aerial images by the Ministry of Environment for the entire Korea since 1998. Even with their wide application in many sectors, their usage in research community is limited. The main reason for this is the map compilation cycle varies too much over the different regions. The situation requires us a new and quicker methodology for generating land cover maps. This study was conducted to automatically generate land cover map using aerial ortho-images and Landsat 8 satellite images. The input aerial and Landsat 8 image data were trained by Residual U-Net, one of the deep learning-based segmentation techniques. Study was carried out by dividing three groups. First and second group include part of level-II (medium) categories and third uses group level-III (large) classification category defined in land cover map. In the first group, the results using all 7 classes showed 86.6 % of classification accuracy The other two groups, which include level-II class, showed 71 % of classification accuracy. Based on the results of the study, the deep learning-based research for generating automatic level-III classification was presented.

• Journal of Korean Society of Disaster and Security
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• v.12 no.3
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• pp.35-49
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• 2019

Currently in 2018, Korea has over 600 operating sewage disposal facilities. The law requires a sewage treatment plant to treat 500 tons or more of water per day, and a small-decentralized sewage treatment facility in a community to treat 50 tons or more to less than 500 tons of water per day. However, most facilities fulfill neither the quantity nor the quality requirements from the original design for such reasons as inflow of rainwater and ground water due to deterioration of pipelines and unauthorized input of wastewater in the pipelines. The research has selected 2 representative cases among the technical diagnosif sewage pipelines in many regions within the country to use it as the baseline of: hourly flowrate and BOD water quality analysis in both clear and rainy days, proper plant operation through inflow rate and ratio calculation, and diagnostic evaluation for deterioration of the pipelines and their accessary structures. This also suggests facilities that treats 500 tons or more of inflow per day to sample and analyze the water hourly for 24 hours once a week in both clear weather and rainy weather considering the influence of rainfall on a regular basis.

• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.392-402
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• 2012

In this study, to analyze the stream health using fish assemblage and make effective management, we conducted fish monitoring in the Hoeya River basin and neighboring streams. A total of 33 species classified into 12 families were collected from 29 sites in 2007. Dominant species was Zacco platypus (Relative abundance, RA: 24.8%), and subdominant species was Rhynchocypris oxycephalus (RA: 16.2%). Eight Korean endemic species and 4 exotic species were identified. Moreover, two species (Opsariichthys uncirostris amurensis and Hemiculter eigenmanni) were translocated from other basin. To evaluate stream health of the study sites, Index of Biological Integrity (IBI) was applied, based on fish assemblages. Overall, IBI values were "C (Fair)" or "D (Poor)" condition, according to the grade except two sites which recorded "B (Good)". The correlation between land use pattern of surrounding watershed and IBI was analyzed to verify impact of development on stream health using fish assemblage. As a result, when percentage of the developmental groups increased, IBI values were decreased (Pearson correlation, r=-0.425, p=0.022). In contrast, increment of percent forest and grass land was positively correlated with IBI (r=0.556, p=0.002). The agricultural group and IBI did not significantly correlate with each other (r=-0.231, p=0.333). In this study, we identified a relationship between land use of surrounding watershed and stream health using fish data (i.e. IBI). These results could be provided useful fundamental information to establish management and restoration plan in the Hoeya River basin and other rivers distributed in Korea.

• Geophysics and Geophysical Exploration
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• v.14 no.1
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• pp.42-49
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• 2011

To locate anomalous features including seepage pathways through the Daeryong earth-fill dam, P and Rayleigh waves were recorded along a 250-m profile on the crest of the dam. Seismic energy was generated using a 5-kg sledgehammer and detected by 24 4.5-Hz vertical-axis geophones installed at 3-m intervals. P-wave and apparent S-wave velocities of the reservoir dam and underlying bedrock were then inverted from first-arrival traveltimes and dispersion curves of Rayleigh waves, respectively. Apparent dynamic Poisson's ratios as high as 0.46 were obtained at the base of the dam near its north-east end, where an outlet conduit occurs, and in the clay core body near the south-west end of the profile where the dam was repeatedly grouted to abate seepage before our survey. These anomalies of higher Poisson's ratios in the upper part of clay core were also associated with effusion of grout on the downstream slope of the dam during post-survey grouting to abate leakage. Combining P-wave traveltime tomography and inversion of Rayleigh wave velocities was very effective in detecting potential pathways for seepage and previous grouted zones in this earthen dam.

• Cartoon and Animation Studies
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• s.31
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• pp.57-89
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• 2013

Animation tool has been made changes rapid development of animation from analog tool to digital authoring tool. Depending on the change in the status of digital authoring tools, education of digital authoring tool has brought many changes occurred in the institute and university. Digital authoring tool was insufficient for research of authoring tool due to the recognition that authoring tool is a simple tool. I try to resolve the difficulties through the analysis digital authoring tools to students studying at the university. In addition, Suggests social/cultural change of animation practitioners and effective training methods of digital authoring tools in the education of beginners and practitioners. This tool have perceptual knowledge and narrative knowledge. Since the language features and knowledge features is difficult to learn. it must be learned knowledge of computer graphics of professional level properly to learn. Then users should try to be creative within the authoring tool to produce creative results. also formed the community and to exchange information for self-development further it should form job market that authoring tool make formed through medium. So, I think that there is a need to change academically attitude to authoring tool. because this is not only the positive side but it occurs phenomenon to enslave users in authoring tool, and blind faith in the authoring tool or critical stance on software. It was a lot of pre-existing research that investigate engineering and industrial side in the authoring tool. Through this thesis, We will find social/cultural features and academic significance, and investigate that how to approach the method of education.