• Journal of Broadcast Engineering
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• v.20 no.2
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• pp.204-214
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• 2015

Depth map upsampling is an approach to increase the spatial resolution of depth maps obtained from a depth camera. Depth map quality is closely related to 3D perception of stereoscopic image, multi-view image and holography. In general, the performance of upsampled depth map is evaluated by PSNR (Peak Signal to Noise Ratio). On the other hand, time-consuming 3D subjective tests requiring human subjects are carried out for examining the 3D perception as well as visual fatigue for 3D contents. Therefore, if an objective metric is closely correlated with a subjective test, the latter can be replaced by the objective metric. For this, this paper proposes a best metric by investigating the relationship between diverse objective metrics and 3D subjective tests. Diverse reference and no-reference metrics are adopted to evaluate the performance of upsampled depth maps. The subjective test is performed based on DSCQS test. From the utilization and analysis of three kinds of correlations, we validated that SSIM and Edge-PSNR can replace the subjective test.

• Spatial Information Research
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• v.8 no.2
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• pp.317-328
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• 2000

It is a well-known fact that groundwater is difficult to be recovered, once it is polluted. Since its damage may continue for a long time, its management is very much necessary. For groundwater pollution managemet, current groundwater quality should be analyzed and its diffusion should be estimated. Such analysis and estimation are greatly enhanced by a GIS. In order to build the GIS, groundwater information management system, various database related to groundwater should be constructed. The system can be utilized to analyze groundwater quality and to help administrative processes of groundwater management. In this study, we analyze No3N diffusion in the groundwater under the study area, a part of Jung-Gu area, by using groundwater analysis subsystem and create the 1/5,000 scale map for the diffusion prediction of groundwater pollution. Although Seoul Metropolitan Government has constructed the 1/25,000 scale hydrogeology map of Seoul area through basic groundwater survey in 1996, the survey data are not sufficient for local groundwater pollution management. The large scaled map constructed in this study is expected to be utilized for the management. The GIS softwares, Arc/Info and Arc/View, are used. MODFLOW and MT3D programs are extensively used to analyze groundwater pollution.

• Journal of Korean Society for Geospatial Information Science
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• v.25 no.2
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• pp.67-74
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• 2017

The D-InSAR is a technique for precisely measuring the subsidence of subsidence using difference of two SAR images. In order to calculate the subsidence using D-InSAR, a high coherence between master image and the slave image is essential. Since the existing D-InSAR method calculates the displacement based on the total coherence, the accuracy of the subsidence is lowered when the coherence map contains mountains or bare-land. In order to solve this problem, in this study, a point having a temporal coherence and spatial coherence of 0.7 or more was extracted to form TIN, and the subsidence was calculated based on this TIN. In addition, we compared the existing D-InSAR technique with the new D-InSAR technique considering spatial and temporal coherence. As a result, the new D-InSAR technique showed smaller standard deviation, relative variance, variation coefficient and quadrature deviation than the existing D-InSAR technique. It is also easy to grasp the trend of the subsidence.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.274-276
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• 2008

At the stage of content convergence into cell phone, technologies for geo-spatial information sharing and searching are being developed. Currently, 2D portable navigation map for mobile navigation is provided by communication companies, but geobrowers for 3D geo-information in cell phone are under developing. In this study, 3D feature transformation among X3D-M3G-KML, on mobile and web environments, is dealt with as the first stage for the further mobile 3D web application. As well, it is possible to real-time interoperable 3D geo-information exchange issues within both environments.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.735-741
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• 2009

In order to support the basic information for planning and performing the environment management such as Total Maximum Daily Loads (TMDLs), it is highly recommended to understand the spatial distribution of water quality and runoff data in the unit watersheds. Therefore, in the present study, we applied Self-Organizing Map (SOM) to detect the characteristics of spatial distribution of Biological Oxygen Demand (BOD) concentration and runoff data which have been measured in the Yeongsan, Seomjin, and Tamjin River basins. For the purpose, the input dataset for SOM was constructed with the mean, standard deviation, skewness, and kurtosis values of the respective data measured from the stations of 22-subbasins in the rivers. The results showed that the $4{\times}4$ array structure of SOM was selected by the trial and error method and the best performance was revealed when it classified the stations into three clusters according to the basic statistics. The cluster-1 and 2 were classified primarily by the skewness and kurtosis of runoff data and the cluster-3 including the basic statistics of YB_B, YB_C, and YB_D stations was clearly decomposed by the mean value of BOD concentration showing the worst condition of water quality among the three clusters. Consequently, the methodology based on the SOM proposed in the present study can be considered that it is highly applicable to detect the spatial distribution of BOD concentration and runoff data and it can be used effectively for the further utilization using different water quality items as a data analysis tool.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.2 s.20
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• pp.39-47
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• 2002

For the purpose of data construction for the systematic management and sight-seeing guidance of the natural park, the Kumoh Mt. Province Park was selected as a pilot area. Digital topographic maps, thematic maps and satellite imagery covering the object area were processed and then landform analysis for elevation, slope, aspect and so on was conducted through DEM generation, and the landcover map and NDVI maP were extracted from Landsat TM data. The database was then constructed with these spatial data for GSIS. The image map was generated from IKONOS satellite data, which cover the pilot area data, with one meter resolution and also 3D visualization which was overlaid with main paths up a mountain were conducted. And the moving image files were produced along main paths up including main natural spectacular sights, cultural assets and management facilities. It is expected that the research result can be utilized as the fundamental data for re-assessing suitable land use and constructing Web-based guidance system.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.604-607
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• 2003

지리정보시스템(GIS)의 사용이 여러 분야에서 점차 확대됨에 따라 단순한 2차원적인 평면 공간상의 수치정보의 제공에서 벗어나 보다 실제적이고 현실감 있는 정보를 제공해 줄 수 있는 지도모델에 대한 요구가 점점 높아져가고 있다. 이에 2차원 지리정보시스템(2D GIS)의 데이터 정보 표현 한계를 극복할 수 있는 대안으로 떠오르고 있는 모델이 3차원 수치지도 정보를 가진 3차원 지리정보시스템(3D GIS)이다. 3차원 수치지도는 2차원 수치지도가 가지는 정보 표현 한계를 벗어나 보다 높은 가독성과 함께 표현한 수 있는 정보량이 높고 다양해 여러 분야로 활용 방안이 가능하다. 따라서 3차원 지리정보시스템에 대한 공간자료(Spatial Data)의 오차한계 극복과, 정밀한 3차원 데이터를 효율성 있게 구축하기 위한 3차원 수치지도의 모델이 요구된다. 본 연구는 부산광역시 해운대구 전 지역을 대상으로 한 3차원 수치지도 측량 및 제작, 이의 활용방안에 대한 연구를 목적으로 진행한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1411-1418
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• 1999

In this paper, we propose a fast motion estimation algorithm using motion prediction and neural network. Considering that the motion vectors have high spatial correlation, the motion vector of current block is predicted by those of neighboring blocks. The codebook of motion vector is designed by Kohonen self-organizing feature map(KSFM) learning algorithm which has a fast learning speed and 2-D adaptive chararteristics. Since the similar codevectors are closely located in the 2-D codebook the motion is progressively estimated from the predicted codevector in the codebook. Computer simulation results show that the proposed method has a good performance with reduced computational complexity.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.4
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• pp.141-149
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• 2010

Three-dimensional geo-spatial information is important for the efficient use and management of the country and the three-dimensional expression and analysis of urban projects, such as urban plans devised by local governments and urban management. Thanks to the revitalization of the geo-spatial information service industry, it is now being variously used not only in public but also private areas. For the creation of high-guiltily three-dimensional geo-spatial information, emphasis should be placed on not only the quality of the source image and three-dimensional geo-spatial model but also the level of visualization, such as level of detail and texturing. However, in the case of existing three-dimensional geo-spatial information, its establishment process is complicated and its data are not updated frequently enough, as it uses ready-created digital maps. In addition, as it uses Ortho Images, the images exist Relief displacement. As a result, the visibility is low and the three-dimensional models of artificial features are simplified to reach LoD between 2 and 3, making the images look less realistic. Therefore, this paper, analyzed the quality of three-dimensional geo-spatial information created using the three-dimensional modeling technique were applied using Digital photogrammetry technique, using digital aerial photo images by an existing large-format digital camera and multi-looking camera. The analysis of the accuracy of visualization information of three-dimensional models showed that the source image alone, without other visualization information, secured the accuracy of 84% or more and that the establishment of three-dimensional spatial information carried out simultaneously with filming made it easier to gain the latest data. The analysis of the location accuracy of true Ortho images used in the work process showed that the location accuracy was better than the allowable horizontal position accuracy of 1:1,000 digital maps.

• Spatial Information Research
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• v.15 no.4
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• pp.397-406
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• 2007

2D hydraulic models of urban areas are at the forefront of current research of flood inundation mechanisms, but they are constrained by inadequate parameters of topography and insufficient data. In this paper a numerical model based on DEMs is presented to represent overflow waters due to bank break in urban areas. The surface flow in the building areas is assumed to be properly modeled by solving Saint-Venant equation. In order to represent flooding broken out in Samcheok city, 2002, hydraulic model test using tracer has been carried out and validated. These efforts will serve for making flood hazard map and for estimating economic loss due to inundation of personal properties in urban areas.