• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.1
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• pp.96-96
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• 2001

The aim of this study was to find out and confirm the project formulation, feasibility, scale and locations on the farmland development projects such as planned and ongoing tideland reclamation and irrigation facilities along the western coast of North Korea using satellite image data, Landsat TM, JERS OPS and SPOT PAN and aged maps. In order to apply to the study, remote sensing technologies such as geometric correction. digital mosaicking, image merging, linear extraction and land cover classification were studied. As the results of the study, the reclaimable tidal flats are recognized at about 178,000 ha equivalent to 59% of announced 300,000ha. and 16,000 ha of completed, 17,000 ha of ongoing project areas although 27,000 ha were revealed to be completed during 1987-1993. Almost planned projects are appeared to be shortage of water supply due to their small watersheds, however, most projects are connected with 2000 mile canal system.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.4 s.15
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• pp.35-42
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• 2004

Accurate classification of water area is a preliminary step to analyze the flooded area and damages caused by flood. This is essential process for monitoring the region where annually repeating flood is a problem. The accurate estimation of flooded area can ultimately be utilized as a primary source of information for the policy decision. In this paper, flooded areas was classified using 1:25,000 land use map and a RADARSAT image of Ok-Chun and Bo-Eun located in Chung-Book province taken in 12th of August, 1998. Then we analyzed the flood area based on GIS. A RADARSAT image was used to classify the flooded areas with slope theme generated from digital elevation model. In processing on a RADARSAT image, the geometric correction was performed by a backwardgeocoding method based on ephemeris data and one control point for near real time flood area analysis.

• Steel and Composite Structures
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• v.34 no.5
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• pp.643-655
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• 2020

In the present work, the buckling behavior of a single-layered graphene sheet (SLGS) embedded in visco-Pasternak's medium is studied using nonlocal four-unknown integral model. This model has a displacement field with integral terms which includes the effect of transverse shear deformation without using shear correction factors. The visco-Pasternak's medium is introduced by considering the damping effect to the classical foundation model which modeled by the linear Winkler's coefficient and Pasternak's (shear) foundation coefficient. The SLGS under consideration is subjected to compressive in- plane edge loads per unit length. The influences of many parameters such as nonlocal parameter, geometric ratio, the visco-Pasternak's coefficients, damping parameter, and mode numbers on the buckling response of the SLGSs are studied and discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.4
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• pp.113-124
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• 1989

In this study, we tried to extract the land-use change information of Seoul city using the multiple date images of the same geographic area. Multiple date image set is MSS('72, '79, '81, '93) and TM('85), and we carried out geometric correction, digitizing(due to the administrative boundary) in pre-processing process. In addition, we performed land-use classification with MLC(Maximum Likelihood Classifier) after improving the predictive accuracy of classification by filtering technique. At the stage of classification, ground truth data, topographic maps, aerial photographs were used to select the training field and statistical data of that time were compared with the classification result to prove the accuracy. As a result, urban area in Seoul has been increased('72 : 25.8 %${\rightarrow}$'81 : 43.0 %${\rightarrow}$'85 : 51.9 %) and Forest area decreased ('72 : 39.0 %${\rightarrow}$'85 : 28.4 %) as we estimated. Finally, it is concluded that the utilzation of satellite imagery is very effective, economical and helpful in the urban land-use/land-cover monitoring.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.345-347
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• 2012

본 논문에서는 4-조각 전립선 병리조직 영상을 기하 보정 및 강체 정합하여 자동 스티칭하는 방법을 제안한다. 4-조각 병리영상에 대하여 총 3번의 스티칭을 수행하는데, 좌, 우 조각영상의 상, 하 영상 간 스티칭을 각각 수행 한 후 좌, 우 조각 영상 간 스티칭을 수행한다. 강체 정합 전 병리 조각의 코너를 이용해 x-축, y-축 방향의 위치보정과 회전보정을 수행하는 기하보정 단계를 거침으로서 지역적 최적해로의 수렴을 방지하며, 강체 정합의 정확성을 높인다. 병리영상은 전체적으로 밝기값이 유사하므로 밝기값이 아닌 외곽선 정보를 이용하여 조각 영상간의 거리를 최소화시켜 강체 정합한다. 실험 결과, 4-조각 전립선 병리조직 영상이 지역적 최적해에 수렴하지 않고, 조각 영상 간 거리를 최소화 하며, 하나로 스티칭 됨을 확인할 수 있었다. 제안 방법의 총 수행 시간은 평균 10.32초로 측정되었다. 본 논문의 제안 방법은 4조각으로 나뉜 전립선 병리조직 영상을 하나로 스티칭 함으로서 해당 조직의 전체 구조 파악 및 조직 내에서의 암의 위치 파악에 사용 될 수 있으며 이를 통한 전립선암의 확진에도 사용 될 수 있다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.12
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• pp.1521-1528
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• 2012

The present paper provides the elastic stress intensity factors (SIFs) and the crack opening displacements (CODs) of a thick-walled pipe with a slanted axial through-wall crack. For estimating these elastic fracture mechanics parameters, systematic three-dimensional elastic finite element (FE) analyses were performed by considering geometric variables, i.e., thickness of pipe, reference crack length, and crack length ratio, affecting the SIFs and CODs. As for loading condition, the internal pressure was considered. Based on the FE results, the SIFs and CODs of slanted axial through-wall cracks in a thickwalled pipe along the crack front and the wall thickness were calculated. In particular, to calculate the SIFs of a thick-walled pipe with a slanted axial through-wall crack from those of a thick-walled pipe with an idealized axial through-wall crack, a slant correction factor representing the effect of the slant crack on the SIFs was proposed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.667-675
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• 2011

In this paper, we propose an automatic image-to-image registration between high resolution multi-sensor images. To do this, TerraSAR-X image was shifted according to the initial translation differences of the x and y directions between images estimated using Mutual Information method. After that, the Canny edge operator was applied to both images to extract linear features. These features were used to design a cost function that finds matching points based on the similarities of their locations and gradient orientations. For extracting large number of evenly distributed matching points, only one point within each regular grid constructed throughout the image was extracted to the final matching point pair. The model, which combined the piecewise linear function with the global affine transformation, was applied to increase the accuracy of the geometric correction, and the proposed method showed RMSE lower than 5m in all study sites.

• Journal of the Korean Society of Radiology
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• v.9 no.3
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• pp.139-145
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• 2015

When examining a patient using SPECT, gamma rays emitted from the body decrease or scatter. And when they reach the detector they spread in accordance with physical characteristics and geometric shapes of the scanner, quantitative analysis was difficult. For exact quantitative analysis of gamma rays emitted from the body, so that they must be considered to correction about PVE(partial volume effect). In this paper, sinogram filter was implemented to solve comprehensive PVE of SPECT. According to the results in which implemented filter was applied, partial volume effect caused by SPECT was removed. To compare proposed method and conventional method, PSNR(Peak Signal to Noise Ratio) was executed. As a result, proposed method was indicated as 7dB, conventional method was indicated as 14db respectively. dB(decibel) level of the proposed methods is lower, since the MSE(mean square error) becomes greater because scattered ray was removed, PSNR value is low. Therefore, by applying the proposed method for removing the PVE of SPECT imaging method, the image quality is improved.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.4
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• pp.285-292
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• 2013

This study proposes a network matching method based on a network division technique. The proposed method generates polygons surrounded by links of the original network dataset, and detects corresponding polygon group pairs using a intersection-based graph clustering. Then corresponding sub-network pairs are obtained from the polygon group pairs. To perform the geometric correction between them, the Iterative Closest Points algorithm is applied to the nodes of each corresponding sub-networks pair. Finally, Hausdorff distance analysis is applied to find link pairs of networks. To assess the feasibility of the algorithm, we apply it to the networks from the KTDB center and commercial CNS company. In the experiments, several Hausdorff distance thresholds from 3m to 18m with 3m intervals are tested and, finally, we can get the F-measure of 0.99 when using the threshold of 15m.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.1
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• pp.95-106
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• 2001

The aim of this study was to find out and confirm the project formulation, feasibility, scale and locations on the farmland development projects such as planned and ongoing tideland reclamation and irrigation facilities along the western coast of North Korea using satellite image data, Landsat TM, JERS OPS and SPOT PAN and aged maps. In order to apply to the study, remote sensing technologies such as geometric correction. digital mosaicking, image merging, linear extraction and land cover classification were studied. As the results of the study, the reclaimable tidal flats are recognized at about 178, 000 ha equivalent to 59% of announced 300, 000ha. and 16, 000 ha of completed, 17, 000 ha of ongoing project areas although 27, 000 ha were revealed to be completed during 1987-1993. Almost planned projects are appeared to be shortage of water supply due to their small watersheds, however, most projects are connected with 2000 mile canal system.