• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.208-208
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• 2011

하구는 하천의 담수와 염수가 교차되고 혼합되는 기 수역으로서 수생 생태계의 중요한 서식처이며 바다와 하천의 중요한 생태통로가 되고 있다. 국내에서는 4대 하천 중에서 한강하구가 유일하게 하구 둑이 없는 자연하구이며 나머지 대하천은 둑으로 인해 담수와 해수의 자연스러운 흐름이 제한되고 생태적인 연결이 단절된 형태이다. 한강하구에는 대규모 습지가 분포하고 있으며 특히 장항습지는 종단길이 약 7.5km, 폭 최대 500m에 달하는 대규모 습지로서 고라니를 비롯한 동물과 줄, 선버들을 비롯한 식물의 대규모 군락이 분포하는 등 생태적 가치가 높은 지역이다. 본 연구에서는 한강하구의 장항습지와 산남습지를 대상으로 특정구간의 물리적 특성, 식생의 분포특성을 파악하고 연관성을 분석하고자 하였다. 이를 위해 1차적으로 포괄적인 현장조사를 통해 전체 식생군락과 분포를 파악하고 특징적인 식생군락을 선정하였다. 2차적으로는 선정된 줄 및 선버들 군락지를 대상으로 토양단면, 토양입경을 분석하고, 새섬매자기 군락지를 대상으로 측량을 실시하였다. 3차적으로는 대상 군락의 지하수위를 측정하여 상호관계를 분석하였다. 이 결과는 우선 한강하구의 지역적 특징에 국한되지만 향후 타 지역과의 비교연구가 수행된다면 대상 식생과 물리적 생장조건과의 정량적인 관계가 도출될 것으로 판단된다.

• Journal of the Korean GEO-environmental Society
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• v.22 no.2
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• pp.35-39
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• 2021

Photogrammetry using drone can produce high-resolution ortho image and acquire high-accuracy 3D information, which is useful. Therefore, this study attempted to determine the possibility of using drone-photogrammetry in park construction by producing a topographic map using drone-photogrammetry and analyzing the problems and accuracy generated during production. For this purpose, we created ortho image and DSM (digital surface model) using drone images and created topographic status map by vectorizing them. Accuracy was compared based on topographic status map by GPS (global positioning system) and TS (total station). The resulting of analyzing mean of the residuals at check points showed that 0.044 m in plane and 0.066 m in elevation, satisfying the tolerance range of 1/1,000 numerical maps, and result of compared lake size showed a difference of about 4.4%. On the other hand, it was difficult to obtain accurate height values for terrain in which existed vegetation when producing the topographic map, and in the case of underground buried objects, it is not possible to confirm it in the image, so direct spatial information acquisition was necessary. Therefore, it is judged that the topographic status map using drone photogrammetry can be efficiently constructed if direct spatial data acquisition is achieved for some terrain.

• Tunnel and Underground Space
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• v.17 no.2 s.67
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• pp.139-151
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• 2007

Stereophotogrammetry is a method to extract information of an interested area by constructing a stereo-image from two or more photos. In this study, the stereophotogrammetry was adopted to obtain the joint orientation and trace length from a sampling window and its measurements were compared with the result by a clinocompass and measuring tape to evaluate the applicability of the stereophotogrammetry to rock joint survey. A commercial stereophotogrammetry program, ShapeMetriX 3D, was used for this purpose. Firstly, the accuracy of the measuring method using ShpaeMetrix 3D was evaluated by a model test. Secondly, joint orientations on a rock slope and tunnel were obtained by using ShapeMetriX 3D and compared with the measurement by a clinocompass. Finally. the effect of base-depth ratio in photographing was evaluated by comparing images with various base-depth ratios, and the usefulness of closed-up photographing on a rock exposure to increase the measurement accuracy was tested. The dip and dip direction of each model plane obtained by ShapeMetriX 3D showed an error ranged between $-5^{\circ}\;and\; 5^{\circ}$ on the basis of the results by the measuring tape. Base-depth ratio proved not to influence the analysis result by ShapeMetriX 3D if all the images were taken without any hidden area. The close-up photographing turned out useful to obtain the detailed images and therefore precise result when ShapeMetriX 3D was adopted.

• Tunnel and Underground Space
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• v.32 no.3
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• pp.194-202
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• 2022

An increased number of cases have occurred in applying ICT technology in the resource development field due to factors such as safety, eco-friendliness, and low cost since the 2000s. In Korea, the 2nd mining master plan specified the significance of converging the full cycle of mining and ICT, while the 3rd mining master plan highlighted ICT and smart mining such as supporting the supply of an ICT mining device and introducing demonstrational smart mining. This study introduces the application of an ICT device and safety system operation in the Jangseong underground mine of Korea Cement Co., Ltd. Currently, Jangseong mine combines two different kinds of 3D equipment including the handheld 3D scanner and multi-station that provides both the measurement and 3D scanning to perform a 3D measurement of the mine. Taken from the 3D measurement of the mine, it is now possible to identify any hazardous areas and abnormalities in different directions and analyze the safety of the crown pillar between two stopes in different level. Besides, the real-time location tracking and communications system have established highly efficient rescue and evacuation plans to effectively deal with any accidents in the mine.

• Journal of the Korean Geophysical Society
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• v.6 no.4
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• pp.269-276
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• 2003

Sub-bottom profile were conducted in Chungju Regulation Lake by use of ground penetrating radar(GPR). The survey area covers approximately 1,000,000 $m^2$ and total survey line length is about 5km and more. GPR surveys with GPS system were made across and transverse direction of the lake. From the survey results of GPR, it could be possible to distinguish the gravel and/or sand dominant bed from silt and/or clay material dominant bed.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.01a
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• pp.257-260
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• 2014

본 논문에는 무선 랜 기반 위치 추적 시스템을 이용하여 실내에 주차된 자동차 위치에 도달하기까지의 방향과 거리 정보를 제공할 수 있는 앱 어플리케이션 설계를 제안한다. 기존 WPS 기능에 삼각측량법을 더하여 정확도를 높이고 실내에 주차된 차량의 위치 관리가 용이하게끔 하는 것을 목적으로 두었다. 이를 위해 WPS와 전파의 세기를 이용한 삼각측량법을 적용하여 설계한 알고리즘을 제시한다. 프로그램 코드 개선 및 구체화는 해당 알고리즘을 가상 환경에서 구현하였다. 스마트폰의 동기화 센서를 이용하여 실시간으로 DB 서버를 접속함으로서 시간 차이로 인해 측정된 위치 정확성이 저하되는 문제를 보정하였다. 따라서 제안한 앱 어플리케이션은 GPS 통신이 불안정한 실내 및 지하에 주차된 자동차의 위치를 사용자가 찾아내는데 효율성을 제공할 수 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.139-139
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• 2018

국내 하천은 산업화와 도시화로 인하여 하천수가 오염되고, 치수를 위한 인공적, 획일적인 하천개수가 보편화 되었다. 그 결과 본래 하천이 가지고 있던 생물서식처 기능과 자정, 친수 기능 등 하천환경 기능이 점차 상실되었고, 하천형태도 변형되었다. 이와 같은 자연적인 변화와 더불어 준설, 수리구조물 설치 등 인위적인 변화에 의하여 흐름 및 유사이송 양상이 바뀌어 하상변동이 초래되기도 한다. 하상변동은 하천 시설물의 안정, 홍수위 및 지하수위 변화, 하천부지의 변화 등 하천관리에 중대한 영향을 미치고, 또한 수생태계의 서식환경에 영향을 미치기 때문에 하천을 복원하는데 있어 중요한 고려사항이 된다. 본 연구의 목적은 청미천 복원 사업 구간에 대하여 장기하상변동 모의를 수행하고 하도 안정성을 평가하는 것이다. 이를 위하여 구하도 복원구간에서 새롭게 수행된 측량데이터를 토대로 지형자료를 구축하였으며, 2차원 하상변동 모의가 가능한 CCHE2D 모형을 이용하여 장기하상변동 모의를 실시하였다. 또한 구하도 복원의 하천지형학적 영향을 평가하기 위하여 구하도를 복원하지 않았을 경우의 시나리오를 도입하여 비교하고 그 결과를 분석하였다.

• Journal of the Korean Geophysical Society
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• v.6 no.3
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• pp.139-153
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• 2003

Subsurface information is one of the most important factors in the archaeological excavation. To obtain the information on the underground, geophysical prospecting is becoming a popular method. This study is on the small rocky islands located 200m away from the shoreline of Gampo, Gyeongju city, Korea. According to the historical records and field surveys, it was revealed as the tomb of King Munmu of Shilla Dynasty. However, the questions and debates, such as whether it is really the tomb of King Moonmu or not, and whether it is a buried place or not, are still remains, in addition to the incompletion of precise surveying and scientific studies. The scope of this study contains the researches on the above problems and debates using the geophysical and geological methods and techniques. The rocky islands around the submerged Tomb of King Moonmu is composed of granite, and sag exists inside of the islands. Sea water enters through the east groove by wave and is drained to the west slot by hydraulic gradient, since west slot is 15cm lower than the east. Sag inside of the islands is believed to be extended and widened from pre-existed sinkage by applying tools like chisel in the joints and cracks. It is concluded that the submerged megalith inside of sag was from the rock block which was developed by joints. Geophysical surveys reveal that there is no artificial structure or stone/china/steel chest, under the m egalith and rocky island. Researches show that the tomb of King Moonmu was constructed in the small rocky island artificially. However, the evidences show that planners and constructors of the tomb made every possible effort to preserve the natural environment and condition. It is strongly believed that the megalith was sort of alter to sprinkle bone-ash rather than buried place.

• Journal of the Korean Geotechnical Society
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• v.38 no.12
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• pp.67-78
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• 2022

In this study, the measurement results of the coastal deep soft ground buried in the upper part of the dredged clay were analyzed and compared with the current specification standards. Based on the results, a suitable proposal was suggested for the selection, installation, data arrangement, and analysis of each instrument used in the deep soft ground improvement construction. The pore water pressure meter has a range of 1.5 times or more of the expected measurement range, considering the field conditions of the soft ground. The groundwater level meter installed in the horizontal drainage layer checks the change in the groundwater level during the embanking as well as the performance of the catchment well and the horizontal drainage layer. Therefore, it is important to manage so that the groundwater level exists inside the horizontal drainage layer during embanking. It is enough to install the inclinometer in the gravel layer below the soft ground or weathered rock with an N value of 40 or more for the deep soft ground. It seems desirable to install a screw type for differential settlement meter. However, the screw type should not settle due to its own weight. Considering that it is a dredged landfill where subsidence occurs significantly, it is sufficient to manage the tolerance of leveling at about 10 mm (L is the one-way distance (km)).

• Journal of Korean Tunnelling and Underground Space Association
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• v.26 no.2
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• pp.113-128
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• 2024

Items of road tunnel PISD (Precise Inspection for Safety and Diagnosis) were reviewed and analyzed using newly enhanced MMS (Mobile Mapping System) technology. Possible items with MMS can be visual inspection, survey and non-destructive test, structural analysis, and maintenance plan. The resolution of 3D point cloud decreased when the vehicle speed of MMS is too fast while the calibration error increased when it is too slow. The speed measurement of 50 km/h is determined to be effective in this study. Although image resolution by MMS has a limit to evaluating the width of crack with high precision, it can be used as data to identify the status of facilities in the tunnel and determine whether they meet disaster prevention management code of tunnel. 3D point cloud with MMS can be applicable for matching of cross-section and also possible for the variation of longitudinal survey, which can intuitively check vehicle clearance throughout the road tunnel. Compared with the measurement of current PISD, number of test and location of survey is randomly sampled, the continuous measurement with MMS for environment condition can be effective and meaningful for precise estimation in various analysis.