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Comparison of Topographic Surveying Results using a Fixed-wing and a Popular Rotary-wing Unmanned Aerial Vehicle (Drone) (고정익 무인항공기(드론)와 보급형 회전익 무인항공기를 이용한 지형측량 결과의 비교)

  • Lee, Sungjae;Choi, Yosoon
    • Tunnel and Underground Space
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    • v.26 no.1
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    • pp.24-31
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    • 2016
  • Recently, many studies have been conducted to use fixed-wing and rotary-wing unmanned aerial vehicles (UAVs, Drones) for topographic surveying in open-pit mines. Because the fixed-wing and rotary-wing UAVs have different characteristics such as flight height, speed, time and performance of mounted cameras, their results of topographic surveying at a same site need to be compared. This study selected a construction site in Yangsan-si, Gyeongsangnam-do, Korea as a study area and compared the topographic surveying results from a fixed-wing UAV (SenseFly eBee) and a popular rotary-wing UAV (DJI Phantom2 Vision+). As results of data processing for aerial photos taken from eBee and Phantom2 Vision+, orthomosaic images and digital surface models with about 4 cm grid spacing could be generated. Comparisons of the X, Y, Z-coordinates of 7 ground control points measured by differential global positioning system and those determined by eBee and Phantom2 Vision+ revealed that the root mean squared errors of X, Y, Z-coordinates were around 10 cm, respectively.

Experiment on Camera Platform Calibration of a Multi-Looking Camera System using single Non-Metric Camera (비측정용 카메라를 이용한 Multi-Looking 카메라의 플랫폼 캘리브레이션 실험 연구)

  • Lee, Chang-No;Lee, Byoung-Kil;Eo, Yang-Dam
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.26 no.4
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    • pp.351-357
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    • 2008
  • An aerial multi-looking camera system equips itself with five separate cameras which enables acquiring one vertical image and four oblique images at the same time. This provides diverse information about the site compared to aerial photographs vertically. The geometric relationship of oblique cameras and a vertical camera can be modelled by 6 exterior orientation parameters. Once the relationship between the vertical camera and each oblique camera is determined, the exterior orientation parameters of the oblique images can be calculated by the exterior orientation parameters of the vertical image. In order to examine the exterior orientation of both a vertical camera and each oblique cameras in the multi-looking camera relatively, calibration targets were installed in a lab and 14 images were taken from three image stations by tilting and rotating a non-metric digital camera. The interior orientation parameters of the camera and the exterior orientation parameters of the images were estimated. The exterior orientation parameters of the oblique image with respect to the vertical image were calculated relatively by the exterior orientation parameters of the images and error propagation of the orientation angles and the position of the projection center was examined.

The Objective Measurement of the Lung Parenchyma Motion for Planning Target Volume Delineation (폐 부위 Planning Target Volume(PTV)설정시 폐 움직임의 객관적 측정)

  • Chung, Weon-Kyu;Cho, Jeong-Gill
    • Radiation Oncology Journal
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    • v.15 no.4
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    • pp.387-392
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    • 1997
  • Purpose : To quantify the movement of lung Parenchyma for ICRU 50 Planning Target Volume (PTV) delineation of the lung region. Materials and Method : Fluoroscopic observations and measurements are Performed on 10 patients with chest region cancer who have normal putmonary functions We have divided the lung region into 12 parts for the right lung, 10 parts for the left lung and four to five Points of lung parenchyma were selected for anatomical analysis Points, Fluoroscopic images are sent to a computer and then movements are measured. Results : Both lowe lobes showed the longest longitudinal movements because of breathing (average 14.1mm, maximum 22.1mm), while anteroposterior displacement showed the smallest value. Lateral movements of the lung parenchyma averaged 6.6mm, and the maximum value was 9.1mm, (both hilar regions showed maximum values because of cardiac motion) Conclusion : We could quantify the lung movements by measuring parenchyma displacements. The movements of both upper lobes were less than those of the middle and upper lobes in longitudinal and transverse movements. Optimal margins can be selected for PTV delineation using these results.

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Problems and Improvement Measures for the transformation of World Geodetic System (지적공부의 세계측지계 변환에 따른 문제점 및 개선방안)

  • Kim, Geun-Bae;Jeong, Gu-Ha;Jeon, Jeong-Bae
    • Journal of Cadastre & Land InformatiX
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    • v.49 no.2
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    • pp.123-134
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    • 2019
  • The introduction of the world geodetic reference system in cadastral sector can apply the international standardization of cadastral survey and can be the basis for the creation of new industries by merging with other industries based on spatial information. With the introduction of the world geodetic reference system, non-coincidence land may cause problems which are whether the cadastral record and the real estate register are not consistent, etc. This problem infringes on the protection of ownership of citizens suggested in the main purpose of 「Act On The Establishment, Management, Etc. Of Spatial Data」. We have analyzed at overlapping cases between private land and overlapping cases between national and public land and suggested institutional improvement measures to solve problems arising on the site. As a result, it will be necessary to introduce a transformation verification measure by the world geodetic reference system in order to assign a function as a cadastral records to mapping converted to the world geodetic reference system. It is also expected that the legal and institutional basis should be established for alert adjustment and positioning through verification measures. Finally, it is difficult to determine the transformation factor as the co-ordinates of common points also differ because survey results vary by work area. Therefore, it is deemed necessary to consider the requirement to use the cadastral measurement basis by the world geodetic reference system in 2021.

Automation of Building Extraction and Modeling Using Airborne LiDAR Data (항공 라이다 데이터를 이용한 건물 모델링의 자동화)

  • Lim, Sae-Bom;Kim, Jung-Hyun;Lee, Dong-Cheon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.27 no.5
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    • pp.619-628
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    • 2009
  • LiDAR has capability of rapid data acquisition and provides useful information for reconstructing surface of the Earth. However, Extracting information from LiDAR data is not easy task because LiDAR data consist of irregularly distributed point clouds of 3D coordinates and lack of semantic and visual information. This thesis proposed methods for automatic extraction of buildings and 3D detail modeling using airborne LiDAR data. As for preprocessing, noise and unnecessary data were removed by iterative surface fitting and then classification of ground and non-ground data was performed by analyzing histogram. Footprints of the buildings were extracted by tracing points on the building boundaries. The refined footprints were obtained by regularization based on the building hypothesis. The accuracy of building footprints were evaluated by comparing with 1:1,000 digital vector maps. The horizontal RMSE was 0.56m for test areas. Finally, a method of 3D modeling of roof superstructure was developed. Statistical and geometric information of the LiDAR data on building roof were analyzed to segment data and to determine roof shape. The superstructures on the roof were modeled by 3D analytical functions that were derived by least square method. The accuracy of the 3D modeling was estimated using simulation data. The RMSEs were 0.91m, 1.43m, 1.85m and 1.97m for flat, sloped, arch and dome shapes, respectively. The methods developed in study show that the automation of 3D building modeling process was effectively performed.

Development of Multi-functional Tele-operative Modular Robotic System For Watermelon Cultivation in Greenhouse

  • H. Hwang;Kim, C. S.;Park, D. Y.
    • Journal of Biosystems Engineering
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    • v.28 no.6
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    • pp.517-524
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    • 2003
  • There have been worldwide research and development efforts to automate various processes of bio-production and those efforts will be expanded with priority given to tasks which require high intensive labor or produce high value-added product and tasks under hostile environment. In the field of bio-production capabilities of the versatility and robustness of automated system have been major bottlenecks along with economical efficiency. This paper introduces a new concept of automation based on tole-operation, which can provide solutions to overcome inherent difficulties in automating bio-production processes. Operator(farmer), computer, and automatic machinery share their roles utilizing their maximum merits to accomplish given tasks successfully. Among processes of greenhouse watermelon cultivation tasks such as pruning, watering, pesticide application, and harvest with loading were chosen based on the required labor intensiveness and functional similarities to realize the proposed concept. The developed system was composed of 5 major hardware modules such as wireless remote monitoring and task control module, wireless remote image acquisition and data transmission module, gantry system equipped with 4 d.o.f. Cartesian type robotic manipulator, exchangeable modular type end-effectors, and guided watermelon loading and storage module. The system was operated through the graphic user interface using touch screen monitor and wireless data communication among operator, computer, and machine. The proposed system showed practical and feasible way of automation in the field of volatile bio-production process.

Rheological Properties of Citrus Pectin Solutions (감귤류 펙틴 용액의 리올리지 특성)

  • Hwang, Jae-Kwan
    • Korean Journal of Food Science and Technology
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    • v.27 no.5
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    • pp.799-806
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    • 1995
  • The steady shear and small amplitude oscillatory dynamic rheological properties of citrus pectin $([\eta]=3.75\;dL/g)$ were characterized for a wide range of pectin concentrations $({\sim}6%)$. The typical power-law flow was observed above 2.0% concentration, and the shear rate dependence of viscosity increased with pectin concentration. The transition from dilute to concentrated regime, determined from the double logarithmic plot of ${\eta_{sp.o}}\;vs\;C[\eta]$, occurred at a critical coil overlap parameter $C^{*}[\eta]\approx4.0$, at which ${\eta_{sp.o}}$ corresponded to approximately 10.0. The slopes of ${\eta_{sp.o}}\;vs\;C[\eta]$, at $C[\eta]\;at\;C[\eta]C^{*}[\eta]$were 1.1 and 4.5, respectively. The steady viscosity $(\eta)$ displayed a good superposition at ${\eta}/{\eta}_o\;vs\;{\gamma}/{\gamma}_{0.8}$ relation with an exception of high concentration (6%), which arised from the significant deviation of flow behavior index (n values of $\eta_{a}=K\gamma^{n-1}$) at high concentration. Dynamic measurements showed that the loss modulus $(G^{\prime\prime})$ was much higher than the storage modulus $(G^\prime)$for all concentrations studied, indicating predominant viscoelastic liquid-like behavior of pectin solutions. The frequency dependence of $G^\prime$ was higher than that of $G^\prime\prime$ at the same concentration, whose trend was more pronounced with decreasing pectin concentration. The shear viscosity $(\eta)$ was almost identical to the complex viscosity $(\eta^{*})$ at low concentration, following the Cox-Merz rule, but they became increasingly different at high concentration.

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The Location Identification Scheme for the Road Management Information System (도로관리정보체계를 위한 도로위치판별방법 설정)

  • Kim, Kwang-Shik;Lee, Kyoo-Seock
    • Journal of Korean Society for Geospatial Information Science
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    • v.1 no.2 s.2
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    • pp.195-206
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    • 1993
  • As the first step in developing the urban information system it is very important to identify the location of the street, and the feature of objects on it Also it is necessary to understand the relationship between objects concerned. In order to manage these information efficiently, the road information should be well organized and standardized for digital data. Because the road is the base place under which most urban utilities are buried. However, the present real situation is that even if we have unique numbers authorized by law for some parts of the road it is too ambiguous to figure out the spatial location of the specific area because the assigned area is so large and incoherent. Therefore, the purpose of this study is to propose a road location identication scheme, to apply this scheme at Kangnam-ku Seoul, and finally to propose the guideline in developing the road management information system in Korea. The road identification scheme developed in this study are as follows: (1) The road is defined as a fixed factor, and was given the identification number which repressents the funtion, relationship, and direction of the road without the road section and absolute coordinates. (2) The parcel identification nutter was given to each route to understand it possible to understand the location of the road itself and surroundings. (3) To update the md information using the scheme developed in this study relative coordinate method(Dynamic Segmentation) based on the road centerline was applied.

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A Numerical Simulation of Three- Dimensional Nonlinear Free surface Flows (3차원 비선형 자유표면 유동의 수치해석)

  • Chang-Gu Kang;In-Young Gong
    • Journal of the Society of Naval Architects of Korea
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    • v.28 no.1
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    • pp.38-52
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    • 1991
  • In this paper, a semi-Lagrangian method is used to solve the nonlinear hydrodynamics of a three-dimensional body beneath the free surface in the time domain. The boundary value problem is solved by using the boundary integral method. The geometries of the body and the free surface are represented by the curved panels. The surfaces are discretized into the small surface elements using a bi-cubic B-spline algorithm. The boundary values of $\phi$ and $\frac{\partial{\phi}}{\partial{n}}$ are assumed to be bilinear on the subdivided surface. The singular part proportional to $\frac{1}{R}$ are subtracted off and are integrated analytically in the calculation of the induced potential by singularities. The far field flow away from the body is represented by a dipole at the origin of the coordinate system. The Runge-Kutta 4-th order algorithm is employed in the time stepping scheme. The three-dimensional form of the integral equation and the boundary conditions for the time derivative of the potential Is derived. By using these formulas, the free surface shape and the equations of motion are calculated simultaneously. The free surface shape and fille forces acting on a body oscillating sinusoidally with large amplitude are calculated and compared with published results. Nonlinear effects on a body near the free surface are investigated.

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A Method for Detecting Event-Location based on Similar Keyword Extraction in Tweet Text (트윗 텍스트의 유사 키워드 추출을 통한 이벤트 지역 탐지 기법)

  • Yim, Junyeob;Ha, Hyunsoo;Hwang, Byung-Yeon
    • Spatial Information Research
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    • v.23 no.5
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    • pp.1-7
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    • 2015
  • Twitter has the fast propagation and diffusion of information compare to other SNS. Therefore, many researches about detecting real-time event using twitter are progressing. Twitter real-time event detecting system assumes every twitter user as a sensor and analyzes their written tweet in order to detect the event. Researches that are related to this twitter have already obtained good results but confronted the limits because of some problems. Especially, many existing researches are using the method that can trace an event location by using GPS coordinate. However, it can be suggested a definite limitation through the present user's skeptical responses about making personal location information public. Therefore, this paper suggests the method that traces the location information in tweet contents text without using the provided location information from twitter. Associated words were grouped by using the keyword that extracted in tweet contents text. The place that the events have occurred and whether the events have surely occurred are detected by this experiment using this algorithm. Furthermore, this experiment demonstrated the necessity of the suggested methods by showing faster detection compare to the other existing media.