• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.1
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• pp.19-30
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• 2005

Korean government has constructed a nationwide cadastral map database through the cadastral map computerization project and also produced a variety of spatial data through the NGIS (National Geographic Information Systems) project. Under this circumstance, it is needed to set up the new automatic methodology that effectively solve cadastral non-coincidence problems by using various digital map data instead of expensive field survey methods. This study proposed a new automatic methodology for cadastral non-coincidence surveying and developed a prototype system as a proof of concept. Validation of this proposed method was done with some test areas. Results showed that this methodology could easily detect and assess both regional non-coincidence levels and cadastral map quadrangle non-coincidence levels. We expect that this new methodology can provide many benefits in planning and determining work priority of the forthcoming nationwide cadastral re-surveying project.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.82-86
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• 2001

The aim of this study was to investigate the level of radiopacity of esthetic dental restorative materials and determine the optimum level of radiopacity in pediatric dentistry. Disks of 8 dental restorative material groups as the experimental group, 7mm in diameter and 2mm thick, were radiographed with intact human deciduous teeth and aluminum stepwedge standard. Radiopacity was evaluated with an image analysis program following the digitization of the radiographs using a flatbed scanner with transparency unit. All materials and tooth structure also the significant difference except FP, VB, VM. For the radiopacity of esthetic restorative dental materials to exceed that of enamel, it should be greater than 1.7mm of equivalent thickness of aluminum.

• Geophysics and Geophysical Exploration
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• v.9 no.2
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• pp.148-154
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• 2006

The effect of small-scale near surface inhomogeneity on Rayleigh wave propagation and dispersion has been investigated in this study using two-dimensional FEM elastic modeling. Various inhomogeneity models with a variety of geometrical shape and embedment depth which exist in homogeneous half-space and two-layered media are considered. Results show that any near surface inhomogeneity greater than one wavelength in terms of minimum wavelength of Rayleigh wave shows dispersion characteristics. Such dispersion effect become stronger as the dimensions of the inhomogeneity increase. The effect of horizontal dimension is more dominant factor governing the dispersion characteristics than vertical dimension. However, the dispersion effect can not be identifiable in seismogram if the horizontal dimension is not wide enough. Nonetheless, even in this case, the existence of inhomogeneity can be inferred by the reflection or transmission event of Rayleigh wave. The results can be expected to provide insights on the behavior of Rayleigh wave which may be helpful for designating field work or new processing scheme to detect near surface inhomogeneity by surface wave method.

• Spatial Information Research
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• v.14 no.3 s.38
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• pp.271-284
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• 2006

This study suggests the adjustment method of cadastral non-coincidence using spatial data referenced digital cadastral map and a present state. In designing the methodology, we should introduce the semi-automatic method for guaranteeing the stability and the accuracy at the arrangement of cadastral non-coincidence based on some cadastral specialist. This study could mainly show you rotation type, bias type, and rotation/bias type among cadastral non-coincidence types. We selected the matching reference point through the prototype system which automatically arranges in the study area. And then, we analysis the optimum rotation ratio(-0.4%). Finally, this paper show you calibrating cadastral non-coincidence using the rotation ratio. The methodology of this study has a limitation for arranging in case of cadastral non-coincidence by the area variation and some irregular types with unknown reason. Therefore, this case should be surveyed in direct method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.915-922
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• 2008

Impervious surface is an important index for the estimation of urbanization and the assessment of environmental change. In addition, impervious surface influences on short-term rainfall-runoff model during rainy season in hydrology. Recently, the necessity of impervious surface estimation is increased because the effect of impervious surface is increased by rapid urbanization. In this study, impervious surface estimation is performed by using remote sensing image such as Landsat-7 ETM+image with $30m{\times}30m$ spatial resolution and satellite image with $1m{\times}1m$ spatial resolution based on Jungnangcheon basin. A tasseled cap transformation and NDVI(normalized difference vegetation index) transformation are applied to Landsat-7 ETM+ image to collect various predict variables. Moreover, the training data sets are collected by overlaying between Landsat-7 ETM+ image and satellite image, and CART(classification and regression tree) is applied to the training data sets. As a result, impervious surface prediction model is consisted and the impervious surface map is generated for Jungnangcheon basin.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.345-346
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• 2010

The overall quality of underwater concrete will ultimately be affected by factors such as performance of antiwashout admixture and mix proportions of concrete. Of these, performance of antiwashout admixture may significantly influence quality of underwater concrete. Thus, objectives of this experimental research are to evaluate the performance such as slump flow, setting time, compressive strength, and water segregation of the concrete containing antiwashout admixture. It was observed from the test results that concrete containing antiwashout admixture was found to improve quality of concrete such as fluidity, compressive strength, and antiwashout compared to plain concrete.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1841-1845
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• 2010

최근 짧은 시간 내에 많은 양의 비가 내리는 게릴라성 집중호우가 도시하천유역의 침수피해사례를 증가시키고 있다. 이러한 집중호우로 인한 도시하천의 침수피해를 방지하기 위해 하천의 1차적인 홍수방지책인 제방의 안전성 검토를 통해 외수침수에 대한 위험성을 점검하며 제내지의 우수관로의 월류로 인한 내수침수에 대한 홍수방지대책확립을 위한 연구들이 진행 중에 있다. 본 연구에서는 한강의 제1지류인 홍제천 수계 중 하나인 불광천을 대상으로 제방취약성 분석 및 홍수규모별로 내수침수위험지역을 산정하여 치수 안전성을 검토하였다. 불광천은 마포구, 서대문구 및 은평구 3개의 행정구역에 포함되는 도시하천으로 하수관로, 우수관로, 하천횡단교량, 보 등의 수공구조물이 설치되어 있다. 불광천의 계획빈도인 50년 빈도와 극한홍수사상을 고려하기 위한 100년 빈도, 200년 빈도에 대한 확률 홍수량과 홍수위를 산정하여 구간별로 월류 위험도 분석에 적용하였다. 확률홍수량 산정은 SWMM모델을 이용하였고 확률홍수위 산정은 HEC-RAS모델을 활용하였다. 또한 SWMM모델을 이용하여 불광천 중류부인 응암지구를 대상으로 홍수규모별로 우수관로에서 월류되는 유역 모의를 수행하였다. 그 결과 제방 안전도 평가기준에 따라 제방위험구간을 선정하고 침수위험지역을 결정하였다. 이를 통해 빠른 홍수예 경보를 통한 홍수 피해 경감방안을 모색하고 불광천의 홍수방재체계 수립에 활용하고자 한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.358-358
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• 2019

도시화 및 산업화로 인해 불투수면이 지속적으로 증가하고 있으며, 불투수면의 증가로 인해 물순환 구조 왜곡이 발생하고 있으며, 이로 인해 집중 호우시 첨두유량 증가로 인한 도시 침수, 자연적 침투량 감소로 인한 지하수 고갈 및 하천 건천화, 도시 열섬 현상 등 다양한 물 문제가 발생하고 있다. 건강한 물순환 체계 회복을 위해, 환경부에서는 소권역별 불투수면적률에 대한 중장기 물순환 목표를 포함하여 물환경보전법을 개정하였으며, 2020년부터 시행예정이다. 본 연구에서는 안성천 유역을 대상으로 소권역별 불투수면적률을 산정하고 불투수면적률 저감에 따른 유출량 등의 유역 물순환 구조 변화를 분석하고자 한다. 불투수면적률은 연속수치지도, 연속지적도, 용도지역 지구도 3개의 지리정보자료를 중첩하여 최신 불투수면적 정보가 반영되도록 계산하였으며, 물순환 구조는 HSPF 모형을 이용하여 분석하였다. 본 연구의 결과는 향후 불투수면적과 물순환 요소간의 상관관계 분석을 위한 기초자료로 활용될 수 있을 것으로 사료된다.

• Journal of Cadastre & Land InformatiX
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• v.45 no.2
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• pp.149-160
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• 2015

This paper suggests the MMAS(Map Matching using Additional Surveying) method to improve the cadastral discrepancy search algorithm that currently does not include corrections of mis-represented parcel data. The MMAS is a method to search for cadastral discrepancy after correcting mis-represented parcel data using nearby anchor points confirmed by surveys. The MMAS first transforms the coordinate system of the digital cadastral map by overlaying anchor points obtained in the field surveying process over the corresponding edges of buildings and facility points on the digital topographic map. Then, it searches for cadastral discrepancy by checking if the area differences exceed the tolerance limit. This method improves the current method for searching for cadastral discrepancy by performing the process after correcting extortion of the digital cadastral map. This helps to identify cadastral discrepancies that are not detectable within the distorted digital cadastral map. With our experiment, this method identified more discrepancies compared to the method without the correcting the distortion of the digital cadastral map. We believe this method will be able to help the national cadastral re-survey by identifying potential cadastral discrepancy more accurately.

• Proceedings of the Korean Statistical Society Conference
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• 2000.11a
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• pp.181-186
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• 2000

완전이면교배를 블록화하는 디자인으로 대개 부분적으로 균형된 불완비 블록계획을 사용한다. 이때 블록화하는 디자인으로 삼각형 PBIBD를 사용하기 위해는 대응되는 삼각형 PBIBD를 찾아야 한다. 특정한 모수를 갖는 균형된 불완비 블록계획의 쌍대계획이 삼각형 PBIBD가 되는 성질을 이용하면 삼각형 PBIBD를 새로 찾아야 하는 번거로움 없이 블록 완전이면교배를 설계할 수 있다. 이를 만족하는 블록 완전이면교배를 설계하는 방법과 디자인을 제시하였다.