• Journal of the Korean Society of Industry Convergence
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• v.24 no.3
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• pp.343-350
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• 2021

Unmanned aerial vehicles(UAV) photogrammetry provides a cost-effective option for collecting high-resolution 3D point clouds compared with UAV LiDAR and aerial photogrammetry. The main objectives of this study were to (1) validate the accuracy of 3D site model generated, and (2) determine the differences between Digital Elevation Model(DEM) and Digital Surface Model(DSM). In this study, DEM and DSM were shown to have varying degree of accuracy from observed data. The results indicated that the model predictions were considered tend to over- and under-estimated. The range of RMSE of DSM predicted was from 8.2 and 21.3 when compared with the observation. In addition, RMSE values were ranged from 10.2 and 25.8 to compare between DEM predicted and field data. The predict values resulting from the DSM were in agreement with the observed data compared to DEM calculation. In other words, it was determined that the DSM was a better suitable model than DEM. There is potential for enabling automated topography evaluation of the prior-harvest areas by using UAV technology.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.10
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• pp.1075-1082
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• 2009

Using GIS data of C-si as basic data when making noise map of road traffic, we estimated exactly the noise excess areas and consequently suggested the population and the area exposed to road traffic noise accurately. We made 3D noise map to assess regional distribution of noise quantitatively. The noise map consists of noise prediction model based on data base such as traffic volume and speed changes for estimating quantitatively the noise and 3D urban space model which includes locations of noise sources, 3D buildings, topography and roads. We made noise standard map according to land use conditions and compared this map to road traffic noise map, and consequently made excess noise map. Using excess noise map, we assessed areas which exceed environmental noise level standards and noise guidelines quantitatively and effectively through GIS spatial analysis, and consequently more accurate noise exposed area and noise exposed population could be estimated. To show buildings' outer walls noise exposure, we analyzed 3D urban noise distributions using 3D-analysis of GIS.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.1255-1255
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• 2022

Recently, research on digital twins to generate digital information and manage construction in real-time using advanced technology is being conducted actively. However, in the construction industry, it is difficult to optimize and apply digital technology in real-time due to the nature of the construction industry in which information is constantly fluctuating. In addition, inaccurate information on the topography of construction projects is a major challenge for earthmoving processes. In order to ultimately improve the cost-effectiveness of construction projects, both construction quality and productivity should be addressed through efficient construction information management in large-scale earthworks projects. Therefore, in this study, a 3D digital map-based AR site management work support system for higher efficiency and accuracy of site management was proposed by using unmanned aerial vehicles (UAV) in wide earthworks construction sites to generate point cloud data, building a 3D digital map through acquisition and analysis of on-site sensor-based information, and performing the visualization with AR at the site By utilizing the 3D digital map-based AR site management work support system proposed in this study, information is able to be provided quickly to field managers to enable an intuitive understanding of field conditions and immediate work processing, thereby reducing field management sluggishness and limitations of traditional information exchange systems. It is expected to contribute to the improvement of productivity by overcoming factors that decrease productivity in the construction industry and the improvement of work efficiency at construction sites.

• The Transactions of the Korea Information Processing Society
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• v.6 no.7
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• pp.1738-1748
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• 1999

Recent simulation tools combine the 3-dimensional graphic technique to implement the 3D visualization of the objects in the 2-Dimensional computer display. In this paper, a sight simulation tool is implemented using the recent 3D techniques. The proposed sight simulator can be applied to improve the human environment with the harmony of the nature. The system is consisted of modules for topography, object, and navigation. A sight database for the sight elements(objects) is implemented using Java. Combined with Java, VRML, which is considered as the standard for 3D virtual reality in the Internet is used to implement EAI(External Authoring Interface). EAI allows the users to communicate with a VRML scene.

• Journal of Environmental Impact Assessment
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• v.20 no.4
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• pp.575-583
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• 2011

In this study, the plausible grid size was estimated to increase for efficiency of reservoir management using 3 dimensional water quality model. To validate utilization of a real time water quality management tool, ELCOM-CAEDYM model was applied to Soyang reservoir in korea. 100m grid size can represent the real topography and take out exact analysis results. $400{\times}400m$ grid can be easily used to analysis because of data capacity. Consequently, the grid size of 200m or 300m was recommended to establish 3D model considering the required simulation time and the irrelevance between horizontal grid size and vertical distribution for temperature and turbidity analysis.

• Journal of Korea Water Resources Association
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• v.31 no.3
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• pp.291-301
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• 1998

The objective of this study is to analyze the characteristics of flow and bed topography with changing bed material in a 180-degree, with constant-radius curved experimental channel. Sand($D_{50}$ = 0.56 mm, s = 2.65) and anthracite($D_{50}$ = 0.26 mm, s = 1.54) were selected as bed materials. The maximum scour depth was found to be about two times for the mean flow depth at the outer bank of bend angle $30^{\circ}~60^{\circ}$, and in case of anthracite, it was found upper part of bend angle $5^{\circ}~15^{\circ}$ than that of sand. Regardless of bed materials the path of maximum streamwise velocity is skewed inwards in the upper part of the bend, the maximum velocity shifts outwards, and it lagged downward as bed roughness increases. The maximum skewed angle of flow grows faster in the smooth bottom than in the rough one, and its value also increases. The secondary flow in anthracite bottom was measured larger than that of sand one, and two cells of secondary flow was found in this experiment.

• KSCI Review
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• v.14 no.2
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• pp.147-152
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• 2006

Data size of moving current GIS great exponentially from 2D to 3D and the processing speed becomes slow thereby and user's real time rendering request is growing. Have problem that time and expense to process data of bulky quantity produce constraint condition of the processing speed. third dimension processing skill, virtual reality processing skill etc. and third dimension GIS about space data of bulk much overmuch to materialize. In this paper DEM data that acquire from satellite or aviation solve these problem embody virtual city in web save topography information that visualization to 3D visualization by VRML, and use modelling tool and acquire 3D campus information for building and road. 3D information acquired this to express texture and natural gifts that have truth stuff more to thing through near texture mapping work 3D imagination illustration of web based embody can.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.2
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• pp.41-47
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• 2008

The import of cartography is spoke for surveying technique level of the country. Also, it is the implied expression means about international operations amount in the world of people in the country. Nowadays, various digital maps on a reduced scale were drawn in Korea including the topographic series of a nation. Though these digital maps are drawn and revised by using aerial photogrammetry or satellite image, there are some problems that it is difficult to revise or renew the topography and natural feature immediately which changes frequently. As the countermeasures of these problems we use 3D Laser Scanning accumbency method, which provides user with convenience and accumbency accuracy which is required to revise and renew digital maps.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.143-148
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• 2008

This Study is about driving simulation after road design by 3D-GIS in digital elevation model from digital aerial photogrammetry. For designing roads efficiently it's very important to consider geographical features before design when analyze the view. Nevertheless, existing studies is mainly restricted in the mountainous, despite of using digital map or aerial photogrammetry and the study which used aerial photo in the area where the road designing is made really is not get executed. Therefore, this study will do 3D-road design and driving simulation by appling really road design data to topography, on the basis of digital elevation generated from aerial photogrammetry.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.3
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• pp.273-281
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• 2011

Purpose: In order to provide the fundamental information for the design development of RGP lenses and its clinical prescription, the corneal types of Korean twenties were analyzed according to corneal shapes, astigmatic degree, and the certain distance from the corneal apex. Methods: Corneal types of total 252 eyes in 20s were firstly classified, then their corneal radii from the certain distance from the corneal apex were measured by corneal topography and further analyzed based on the astigmatic degree. Results: Korean 20s' corneal types were classified as 14.3%(36 eyes) of round, 31.3%(79 eyes) of oval, 28.6%(72 eyes) of symmetric bow tie, 17.5%(44 eyes) of asymmetric bow tie, 8.3%(21 eyes) of irregular shapes. The round and oval typed corneas had mild astigmatic degree whereas the higher astigmatic degree in symmetric and asymmetric bow tie typed corneas were shown. The relative corneal radii of round and oval typed corneas at each distance from corneal apex were shown to consistently increase regardless of astigmatic degrees when they measured at certain distances from the corneal apex. However, the relative corneal radii of symmetric and asymmetric bow tie typed corneas within 1.0-1.5mm from the corneal apex were decreased, which showed steeper slope than it within 1.0 mm and somewhat different based on astigmatic degrees. Bigger change of corneal radii outer 3.5 mm from the corneal apex in symmetric bow tie typed corneas with astigmatism of 1.50-2.00 D and 2.25-2.75 D appeared. Conclusions: The consideration of radial change from the central cornea to peripheral cornea is necessary for manufacturing RGP lens and its prescription since they showed different change in corneal radii by corneal patterns and astigmatic degrees.