• The Journal of Engineering Geology
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• v.16 no.1 s.47
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• pp.23-30
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• 2006

This study was carried out to understand the relationship between orientation of tecto-lineaments obtained from aero-photograph and orientation of discontinuities measured at field for the rock types of igneous, sedimentary and metamorphic rocks in Andong area. Total 847 tecto-lineaments were extracted from the aero-photographs and total 1,940 discontinuities including joints, foliations and faults were measured during geologic survey. By using the software DIPS, preferred trends of tecto-lineaments were deduced as N30E-N40E for igneous rocks and N50E-N60E for both sedimentary and metamorphic rocks, while the trends of discontinuities were found as N40E-N50E for igneous rocks, N50E-N80E for sedimentary rocks and N50E-N60E for meta morphic rocks. Even though both orientations for a given rock type showed relatively good agreement in its trend, some discrepancy is also appeared. Since construction safety of geo-structures such as tunnel and slope, etc., is significantly affected by the orientation of discontinuities in rock masses, it is highly recommended to perform a detailed geologic survey as well as an aero-photograph interpretation at a design stage.

• Journal of radiological science and technology
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• v.35 no.2
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• pp.133-139
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• 2012

For the examination of nuclear medicine, myocardial scan is a good method to evaluate a hemodynamic importance of coronary heart disease. but, the automatized qualitative measurement is additionally necessary to improve the decoding efficiency. we suggests the creation of cardiac three-dimensional model and model of three-dimensional cardiac thickness as a new measurement. For the experiment, cardiac reduced cross section was obtained from SPECT. Next, the pre-process was performed and image segmentation was fulfilled by level set. for the modeling of left cardiac thickness, it was realized by applying difference equation of two-dimensional laplace equation. As the result of experiment, it was successful to measure internal wall and external wall and three-dimensional modeling was realized by coordinate. and, with laplace formula, it was successful to develop the thickness of cardiac wall. through the three-dimensional model, defects were observed easily and position of lesion was grasped rapidly by the revolution of model. The model which was developed as the support index of decoding will provide decoding information to doctor additionally and reduce the rate of false diagnosis as well as play a great role for diagnosing IHD early.

• Journal of Radiation Protection and Research
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• v.11 no.2
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• pp.130-138
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• 1986

A study on the measurement of alpha activity in ground air has been carried out using CA 80-15 and LR 115-1 cellulose nitrate nuclear track detectors. The detection efficiency of the detectors were determined by making use of an $^{241}Am$ alpha source of $0.1{\mu}Ci$ in activity under a known geometrical arrangement. For the field measurement of alpha activity of emanated radon and its progeny in ground air two different radon cups were installed for a certain period of time in two neighbouring ground holes of about 15 cm in diameter and 45 cm in depth. Of the two radon cups one kept closed space during the detecting period, while the other kept open space with a hole enabling the air to ventilate. The etched tracks were read out by a microscope and the results obtained through statistical analysis were evaluated in terms of alpha activity per unit volume of air.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.229-229
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• 2021

최근 이상기상으로 국지성 집중호우가 빈번하게 발생함에 따라 토사유출에 의해 피해가 증가하고 있다. 급경사 사면을 갖는 교란산지와 개발지의 경사면은 토양침식 위험에 노출되어 있다. 특히 지표유출수의 집중흐름에 의한 세류발달은 세류간침식에 비해 많은 토양침식과 토사유출을 발생시킨다. 이러한 급경사 사면에서의 세류발달에 대한 수리학적 메터니즘과 한계조건을 파악하고자 강우와 유입수 모의를 통한 토양침식 실험을 수행하였다. 강우와 유입수의 상호작용에 의한 세류발달의 특성과 토사유출량 증가를 파악하고자, 강우량의 증가와 유입수 유무에 따른 실험이 이루어졌다. 강우강도의 범위는 100~140mm/hr이고, 유입수는 170ml/s 이였다. 유입수량은 합리식으로 계산하였으며, 토양상자 상단에서 균등분사식으로 유입되었다. 세류발달의 수리학적 특성치를 취득하기 파악하기 위해, 염료주입 지표수 거동에 대한 동영상을 판독하였다. 세류발달은 유입수가 없는 경우 3분 이내 그리고 유입수가 있는 경우 30초 이내에 발생하였다. 토양상자내의 평균 유속범위는 7.83~29.27 cm/s 이였다. 실험에서 발달된 세류는 15분경과 후부터 평형상태를 유지하였다. 경사실험조건별로 세류 차수분석을 위해 각 세류의 최대길이, 폭, 넓이를 측정한 결과 세류의 차수는 강우만 있는 경우 1~2차로 발달하였으며, 유입수가 있을 때는 2~3차로 발달하였다. 지표유출이 증가하면서 세류발달의 개수는 줄었지만 규모는 더 크게 나타났다. 세류가 발달하는 시점의 한계유속은 10~20cm/s 범위인 것으로 파악되었다. 지표유출이 증가하면서 세류의 발달도 더 심화되지만, 동일한 강우에 일정시간동안 노출되면서 세류는 평형상태가 되어 더 이상 침식이 활발하게 진행되지는 않았다. 유입수가 있는 조건에서 수량은 약 2배가 증가하였지만, 토사유출량은 세류확장에 의해 약 4배가 증가하는 것으로 나타났다.

• Journal of Korea Water Resources Association
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• v.57 no.5
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• pp.321-332
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• 2024

Understanding the status of surface cover in riparian zones is essential for river management and flood disaster prevention. Traditional survey methods rely on expert interpretation of vegetation through vegetation mapping or indices. However, these methods are limited by their ability to accurately reflect dynamically changing river environments. Against this backdrop, this study utilized satellite imagery to apply the Random Forest method to assess the distribution of vegetation in rivers over multiple years, focusing on the Naeseong Stream as a case study. Remote sensing data from Sentinel-2 imagery were combined with ground truth data from the Naeseong Stream surface cover in 2016. The Random Forest machine learning algorithm was used to extract and train 1,000 samples per surface cover from ten predetermined sampling areas, followed by validation. A sensitivity analysis, annual surface cover analysis, and accuracy assessment were conducted to evaluate their applicability. The results showed an accuracy of 85.1% based on the validation data. Sensitivity analysis indicated the highest efficiency in 30 trees, 800 samples, and the downstream river section. Surface cover analysis accurately reflects the actual river environment. The accuracy analysis identified 14.9% boundary and internal errors, with high accuracy observed in six categories, excluding scattered and herbaceous vegetation. Although this study focused on a single river, applying the surface cover classification method to multiple rivers is necessary to obtain more accurate and comprehensive data.

• Proceedings of the KSRS Conference
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• 2008.03a
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• pp.59-62
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• 2008

고해상도 위성영상의 관측시, 위성센서는 보통 지표면으로부터 어느정도의 기울기를 갖는 상태에서 촬영이 되기 때문에 영상 내에서 건물은 지표면에 누워있는 형태로 나타나게 된다. 때문에 건물의 옆벽면 및 지붕에 의해 지표의 일부가 가려지게 되는데 이를 건물에 의한 폐색영역이라 한다. 이러한 폐색영역은 건물의 기복오차가 제거된 정사영상에서는 검게 비어있는 상태로 남게 되며 시각적으로나 영상판독시 불편을 초래하여 위성영상을 베이스 맵으로 사용하기 어렵게 하는 요인이 된다. 이러한 폐색영역을 보정하기 위해서는 일반적으로 동일 영역에 대한 두 장 이상의 영상을 이용하여 폐색 지역을 채워넣는 작업을 수행하나, 이 방법은 위성영상 구입 및 처리 비용에 대한 부담이 커 실제로 자주 사용되지 못 한다. 본 연구에서는 고해상도 위성 단영상의 건물에 의한 폐색영역에, 주변 화소값들의 분광 및 기하학적 특성을 이용하여 복원하는 기술인 inpainting 기법을 적용하여 그 보정 결과를 평가하고 활용 가능성을 검증해보고자 한다.

• The Journal of the Korea Contents Association
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• v.11 no.6
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• pp.76-89
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• 2011

The first purpose of this paper is to design brand logo sign analysis frame, 'SCoL'(Analysis frame of signification and communication for the brand logo). It has semiotic view and communication function. And the second is to prove propriety of the suggested frame by application to social media brand logos. The SCoL frame is based on 4 features of logo sigh to have analytic consistency. Also, it covers whole semiological process with index, icon, symbol as signification understanding and reach communication step with Jakobson's theory. As the results, the findings are follow; The SCoL frame can be useful to get comprehensive semiotic understandings and communication functions about logo signs. The social media brands build their own meaning area with logo signs and they depend on different communication function.

• Korean Journal of Remote Sensing
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• v.27 no.5
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• pp.587-599
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• 2011

As one measure of image interpretability, NIIRS(National Imagery Interpretability Rating Scale) has been used. Unlike MTF(Modulation Transfer Function), SNR(Signal to Noise Ratio), and GSD(Ground Sampling Distance), NIIRS can describe the quality of overall image at user's perspective. NIIRS is observed with human observation directly or estimated by edge analysis. For edge analysis specially manufactured artificial target is used commonly. This target, formed with a tarp of black and white patterns, is deployed on the ground and imaged by the satellite. Due to this, the artificial target-based method needs a big expense and can not be performed often. In this paper, we propose a new edge analysis method that enables to estimate NIIRS accurately. In this method, natural targets available in the image are used and characteristics of the target are considered. For assessment of the algorithm, various experiments were carried out. The results showed that our algorithm can be used as an alternative to the artificial target-based method.

• Journal of the Korean Geographical Society
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• v.40 no.1 s.106
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• pp.27-46
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• 2005

Land suitability assessment(LSA) is a useful method to assess land characteristics according to its physical, locational, and environmental characteristics, and then to classify it into several categories based on its usability and the necessity for conservation. Therefore, the credibility of this assessment result depends on the rationality of assessment method such as computation of suitability values and the criteria of ranking the land grade. This study focused on identifying problems in current LSA method by critically reviewing it, and aimed to suggest a suitable method for the assessment of land suitability. As a alternative method in this study, linear transformation method was used for scoring factors instead of critical values and the weight for each assessment factor. and all values of those factors were added to produce comprehensive suitability values. Those values were ordered and categorizied with suitability level based on the ratio of square measure. After comparing existing LSA method to the suggested alternative method, it is concluded that the alternative method was more suitable to assess the characteristics of lands than existing LSA method. This method was also suitable to represent the characteristics of various assessment factors. Field survey using satellite image clearly revealed the suitability of the alternative method compared to an existing method of land assessment. Furthermore, the alternative method of grading the land suitability improves the problem of using standardiZiation method and gives more flexibility, which makes this method very rational.

• Journal of Korea Water Resources Association
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• v.33 no.4
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• pp.427-435
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• 2000

It is often crucial to obtain a map of flood inundated area with more accurate and rapid manner. This study attempts to evaluate the potential of satellite synthetic aperture radar (SAR) data for mapping of flood inundated area in Imjin river basin. Multitemporal RADARSAT SAR data of three different dates were obtained at the time of flooding on August 4 and before and after the flooding. Once the data sets were geometrically corrected and preprocessed, the temporal characteristics of relative radar backscattering were analyzed. By comparing the radar backscattering of several surface features, it was clear that the flooded rice paddy showed the distinctive temporal pattern of radar response. Flooded rice paddy showed significantly lower radar signal while the normally growing rice paddy show high radar returns, which also could be easily interpreted from the color composite imagery. In addition to delineating the flooded rice fields, the multitemporal radar imagery also allow us to distinguish the afterward condition of once-flooded rice field.