• Korean Journal of Remote Sensing
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• v.39 no.5_4
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• pp.1135-1144
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• 2023

Many agricultural reservoirs in South Korea, constructed before 1970, have become aging facilities. The majority of small-scale reservoirs lack measurement systems to ascertain basic specifications and water levels, classifying them as unmeasured reservoirs. Furthermore, continuous sedimentation within the reservoirs and industrial development-induced water quality deterioration lead to reduced water supply capacity and changes in reservoir morphology. This study utilized Light Detection And Ranging (LiDAR) sensors, which provide elevation information and allow for the characterization of surface features, to construct high-resolution Digital Surface Model (DSM) and Digital Elevation Model (DEM) data of reservoir facilities. Additionally, bathymetric measurements based on multibeam echosounders were conducted to propose an updated approach for determining reservoir capacity. Drone-based LiDAR was employed to generate DSM and DEM data with a spatial resolution of 50 cm, enabling the display of elevations of hydraulic structures, such as embankments, spillways, and intake channels. Furthermore, using drone-based hyperspectral imagery, Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) were calculated to detect water bodies and verify differences from existing reservoir boundaries. The constructed high-resolution DEM data were integrated with bathymetric measurements to create underwater contour maps, which were used to generate a Triangulated Irregular Network (TIN). The TIN was utilized to calculate the inundation area and volume of the reservoir, yielding results highly consistent with basic specifications. Considering areas that were not surveyed due to underwater vegetation, it is anticipated that this data will be valuable for future updates of reservoir capacity information.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.274-279
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• 2003

위성영상을 이용한 새만금 지역의 DEM생성을 위하여 waterline method를 사용하였으며, 총 13개의 Landsat thematic mapper (TM) 위성영상 자료를 이용하여 1991년과 2000년 기준의 DEM을 생성하였다. 현장 수준측량 자료를 이용하여 생성된 DEM의 정밀도 검증을 실시하였으며, 2002년 3월에 100m 간격으로 측정된 실측자료를 이용하였다. 해안선 추출은 density slicing 방법을 사용하였으며, 사용된 밴드는 육지의 경계를 구분하는데 많이 쓰이는 밴드 4번, 5번 및 6번 밴드를 선택적으로 사용하였다. 절대고도 값의 대입을 위하여 waterline 추출에 사용된 위성영상의 획득 시간에 대해 해양조사원의 10분 간격 실측 조위를 사용하였으며, 추출된 13개 waterline의 최저 조위는 58cm 이고 최고 조위는 537cm 이다. 추출된 해안선에 수준측량 자료를 이용하여 검증한 결과 RMS 오차 9.91 cm, 표준편차 9.78 cm의 정밀도를 갖는 2000년도 DEM을 생성하였다. 새만금 지역의 waterline 추출 과정에서 만경강과 동진강 하구 지역은 강에 의한 에너지의 유입, 유출로 인한 변화가 심하여 두 지역을 DEM 생성에서 제외하였다. 이렇게 생성된 과거(19991년도) DEM과 현재(2000년도) DEM을 이용한 지형변화 비교는 두DEM 차이로 9년간의 새만금 조간대 변화를 계산하였다. 군산공항지역의 지형변화는 거의 없는 것으로 나타났으며, 새만금 방조제가 건설된 이후 개화도 주변지역의 변화가 가장 두드러진 지형적 변화로서 방조제 입ㆍ출구 지역은 빠른 유속에 의해서 과거에 비해 침식이 우세하며, 방조제에서 육지로 갈수록 퇴적이 우세한 것으로 관측되었다.보체계의 구축사업의 시각이 행정정보화, 생활정보화, 산업정보화 등 다양한 분야와 결합하여 보다 큰 시너지 효과와 사용자 중심의 서비스 개선을 창출할 수 있는 기반을 제공할 것을 기대해 본다.. 이상의 결과를 종합해볼 때, ${\beta}$-glucan은 고용량일 때 직접적으로 또는 $IFN-{\gamma}$ 존재시에는 저용량에서도 복강 큰 포식세로를 활성화시킬 뿐 아니라, 탐식효율도 높임으로써 면역기능을 증진 시키는 것으로 나타났고, 그 효과는 crude ${\beta}$-glucan의 추출조건에 따라 달라지는 것을 알 수 있었다.eveloped. Design concepts and control methods of a new crane will be introduced in this paper.and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model,

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1099-1104
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• 2007

The visual implementation of 3-dimensional national environment is focused by the requirement and importance in the fields such as, national development plan, telecommunication facility deployment plan, railway construction, construction engineering, spatial city development, safety and disaster prevention engineering. The currently used DEM system using contour lines, which embodies national geographic information based on the 2-D digital maps and facility information has limitation in implementation in reproducing the 3-D spatial city. Moreover, this method often neglects the altitude of the rail way infrastructure which has narrow width and long length. There it is needed to apply laser measurement technique in the spatial target object to obtain accuracy. Currently, the LiDAR data which combines the laser measurement skill and GPS has been introduced to obtain high resolution accuracy in the altitude measurement. In this paper, we first investigate the LiDAR based researches in advanced foreign countries, then we propose data a generation scheme and an algorithm for the optimal manage and synthesis of railway facility system in our 3-D spatial terrain information. For this object, LiDAR based height data transformed to DEM, and the realtime unification of the vector via digital image mapping and raster via exactness evaluation is transformed to make it possible to trace the model of generated 3-dimensional railway model with long distance for 3D tract model generation.

• Korean Journal of Construction Engineering and Management
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• v.10 no.6
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• pp.3-12
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• 2009

In order to effectively distribute the resources, it is very critical to understand the status or progress of construction site quickly and accurately. Augmented Reality (AR) can provide this situation with information which is convenient and intuitive. Conventional implementation of AR in outdoor or construction site condition requires additional sensors or markers to track the position and direction of camera. This research is aimed to develop the technologies which can be utilized in gathering the information of constructing or constructed buildings and structures. The AR technique that does not require additional devices except for the camera was implemented to simplify the system and improve utility in inaccessible area. In order to do so, the position of camera's perspective center and direction of camera was estimated using exterior orientation techniques. And 3D drawing model of building was projected and overlapped using this information. The result shows that by using this technique, the virtual drawing image was registered on real image with few pixels of error. The technique and procedure introduced in this paper simplifies the hardware organization of AR system that makes it easier for the AR technology to be utilized with ease in construction site. Moreover, this technique will help the AR to be utilized even in inaccessible areas. In addition to this, it is expected that combining this technique and 4D CAD technology can provide the project manager with more intuitive and comprehensive information that simplifies the monitoring work of construction progress and planning.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.573-581
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• 2020

Using CCTV images and weather parameters, a method for estimating PM (Particulate Matter) index was proposed, and an experiment was conducted. For CCTV images, we proposed a method of estimating the PM index by applying a deep learning technique based on a CNN (Convolutional Neural Network) with ROI(Region Of Interest) image including a specific spot and an full area image. In addition, after combining the predicted result values by deep learning with the two weather parameters of humidity and wind speed, a post-processing experiment was also conducted to calculate the modified PM index using the learned regression model. As a result of the experiment, the estimated value of the PM index from the CCTV image was R2(R-Squared) 0.58~0.89, and the result of learning the ROI image and the full area image with the measuring device was the best. The result of post-processing using weather parameters did not always show improvement in accuracy in all cases in the experimental area.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.5
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• pp.421-428
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• 2022

The earthwork is a core process of all constructions, and compaction measurement of earthwork play an important role in improving productivity. The analog tests such as Plate Bearing Test and Sand-cone occupy current compaction measurement techniques. Due to advanced 4th Industrial Revolution, research on analog tests combined smart construction technology are actively conducted. DCPT (Dynamic Cone penetration Test), simpler and faster than conventional tests, has recently on rise. However, it is also an analog that measures data manually and has several disadvantages such as history management and data verification. The IoT-based DCPT system developed in this study combines digital wire sensors, mobile phones, and Bluetooth with conventional DCPT. Compare to conventional test methods, IoT-based DCPT has advantages such as performance time, single-person measurement, low cost, mobile-based management, and real-time data verification. In addition, a test bed was built to verify IoT-based DCPT. The test bed was built under similar conditions to the actual earthworks site through roller equipment. DCPT data obtained from 322 stations. As a result, IoT-based DCPT showed good performance, and the test bed was also showed stable results as the compaction was carried out.

• Journal of the Korea Society of Computer and Information
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• v.28 no.1
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• pp.49-54
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• 2023

The Global Positioning System (GPS) was developed for military purposes and developed as it is today by opening civilian signals (GPS L1 frequency C/A signals). The current satellite orbits the earth about twice a day to measure the position, and receives more than 3 satellite signals (initially, 4 to calculate even the time error). The three-dimensional position of the ground receiver is determined using the data from the radio wave departure time to the radio wave Time of Arrival(TOA) of the received satellite signal through trilateration. In the case of navigation using GPS in recent years, a location error of 5 to 10 m usually occurs, and quite a lot of areas, such as apartments, indoors, tunnels, factory areas, and mountainous areas, exist as blind spots or neutralized areas outside the error range of GPS. Therefore, in order to acquire one's own location information in an area where GPS satellite signal reception is impossible, another method should be proposed. In this study, IMU(Inertial Measurement Unit) combined with an acceleration and gyro sensor and a geomagnetic sensor were used to design a system to enable location recognition even in terrain where GPS signal reception is impossible. A method to track the current position by calculating the instantaneous velocity value using a 9-DOF IMU and a geomagnetic sensor was studied, and its feasibility was verified through production and experimentation.

• 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 Korea Water Resources Association
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• v.56 no.2
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• pp.139-150
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• 2023

Terretial LiDAR surveying is highly useful for maintenance of civil facilities as it can easily detect the temporal deformation of structures or topography. However, for river facilities such as levess, it is difficult to detect the deformation of the topography or structure under vegetations due to the influence of vegetation. Vegetation filters can be divided into color filters and morphological filters. In this study, combined filters with color and morphology are developed to improve the accuracy of vegetation filters. 8 color filters, 6 morphological filters, and 4 combined filters are applied to the vegetation removal on the embankment slope, and their accuracy and calculation time are compared. Color filters show a short calculation time, but the accuracy was low in the vegetation area. Morphological filters show high accuracy in the vegetation area, but low accuracy in places with severe local topographical changes such as heavy rocks. Combined filters also show a tendency similar to morphological filters, but in the case of ExGGM, the accuracy is excellent in both the vegetation and rock area. Considering the accuracy and calculation time, the combined filter ExGGM is suitable for general cases, and the shape filter GrMIn or the complex filter ExGISL is suitable for cases where the local topographical change is not severe.

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.763-770
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• 2005

Global Navigation Satellite System (GNSS) has become an indispensable tool for providing precise position, velocity and time information for many applications like traditional surveying and navigation etc. However, Global Positioning System (GPS), which was developed and is maintained and operated by the U.S. Department of Defence (DoD), has monopolized the world industry and market, and hence there exists the situation that most of GNSS users absolutely depend upon the GPS. In order to overcome the monopoly, some countries, such as Russia, Japan and European Union (EU), have developed their own GNSSs, so-called GLONASS, JRANS and Galileo systems. Among them, the most prospective system in near future is EU's Galileo system scheduled to launch in 2008. This research has focused on the next generation GNSS system based on GPS and Gralileo system with developing a GNSS simulation software, named as GIMS2005, which generates and analyzes satellite constellation and measurements. Based on the software, a variety of simulation tests have been carried out to recognize limits of GPS-only system and potential benefits of integrated GPS/Galileo positioning. Geometry simulation results have showed that comparing with GPS-only case, the number qf visual satellites, Dilution of Precision (DOP) values, internal reliabilities and external reliabilities.