• Journal of KIISE
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• v.43 no.4
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• pp.419-429
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• 2016

Generating a 3D surface model from coronary artery segmentation helps to not only improve the rendering efficiency but also the diagnostic accuracy by providing physiological informations such as fractional flow reserve using computational fluid dynamics (CFD). This paper proposes a method to generate a triangular surface mesh using vessel structure information acquired with coronary artery segmentation. The marching cube algorithm is a typical method for generating a triangular surface mesh from a segmentation result as bit mask. But it is difficult for methods based on marching cube algorithm to express the lumen of thin, small and winding vessels because the algorithm only works in a three-dimensional (3D) discrete space. The proposed method generates a more accurate triangular surface mesh for each singular vessel using vessel centerlines, normal vectors and lumen diameters estimated during the process of coronary artery segmentation as the input. Then, the meshes that are overlapped due to branching are processed by mesh merging and merged into a coronary mesh.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.6_2
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• pp.613-623
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• 2007

The main purpose of this study is to investigate the coordinate transformation based on two different systems between local geodetic datum(tokyo datum) and international geocentric datum(new Korea geodetic datum). For this purpose, three methods were used to determine seven parameters as follows: Bursa-Wolf model, Molodensky-Badekas model, and Veis model. Also, we adopted multiple regression equation method to convert from Tokyo datum to KTRF. We used 935 control points as a common points and applied gross error analysis for detecting the outlier among those control points. The coordinate transformation was carried out using similarity transformation applied the obtained seven parameters and the precision of transformed coordinate was evaluated about 9,917 third or forth order control points. From these results, it was found that Bursa-Wolf model and Molodensky-Badekas model are more suitable than other for the determination of transformation parameters in Korea. And, transforming accuracy using MRE is lower than other similarity transformation model.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.3 s.21
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• pp.29-40
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• 2002

In photogrammetry, the accuracy is analyzed by using the coordinate of the targeted position determined by the geometric principle, thus, the reliability depends on the accuracy of the coordinate of the targeted position. Thereby, geographic surveying is essential to perform such tasks, and it requires approximately $30{\sim}50%$ of total cost and times to produce a finalized map. The main purpose of this study is to determine the configuration of the disposition of minimum datum points and their configuration, which were determined by surveying values available through using the structure of block model based on the aerotriangulation. ortho projection image was produce and digital topographic map was achieved by the optima model(CASE7). We also performed comparative analysis about the result of local datum point and the accuracy of overlapping based on the surveying results. Consequently, it is possible to analyze the unknown position accurately with the optimal model., CASE 7, which is the minimum datum points configuration required to block adjustment. Furthermore, this optimal model, which provides the minimum datum points, results costs and time saving effects compared to the previous methodology.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.3
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• pp.3-13
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• 2008

The coordinate of cadastral control points located over the area of different surveying origins is computed in a single surveying origin by trilateration adjustment of GPS baseline measurements. In every different surveying origins, well-matched control points are selected and mutually coinciding coordinates are computed by free network adjustment. Then, the coordinate of the other control points over the area is computed by joining these points to the adjusted points. In practice, by using 18 points of Gari, 17 points of Gyeyang, and 33 points of Central origin in Incheon, the coordinates of total 68 points in every surveying origin are computed. Between the points of different surveying origins, it is found that there are quantitative differences in azimuth and scale factors and the approximate point coordinate of other surveying origins is calculated by correcting the scale and azimuth.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.106-115
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• 2007

농촌진흥청에서 제공하고 있는 수치토양도는 수문 수자원 분야에서 SCS-CN법을 이용한 유효우량 및 유출곡선 산정에 가장 많이 활용되고 있다. 토양조사 국책사업 결과 전산화된 토양도 및 토양검정 데이터베이스에 기초한 토양정보 웹 시스템은 전국의 토양 전자지도와 토양 통계 자료를 주제별로 검색하거나 필지별 토양분석 성적에 따른 토양관리처방서를 조회하는데 사용되는 농업분야 이외의 사용자 그룹을 위해 필요한 정보를 제공하도록 활용 및 유통 요구도가 높아지고 있다. 수치토양도가 수문학적 토양유형 정보를 포함하도록 제공하는 것이 먼저 필요할 것으로 생각되고 다음으로는 수문 수자원 분야 활용 측면에서 수치토양도가 제공하는 속성, 축척, 제공형태, 좌표체계, 서비스 방식 등에 대하여 활용정책을 마련하여 이에 따라 자료가 유통될 수 있도록 하여야 할 것이다. 앞으로 활용이 가능하게 될 수치세부정밀토양도와 토양유형을 이용하여 충북 괴산군 소수면의 소유역에 대해 SCS 삼각법에 따른 단위도 작성, 유효우량 산출 및 유출곡선을 작성한 결과 농업과학기술원의 정 등(2006)이 분류한 토양유형을 이용한 결과 정 등(1995)에 따른 토양유형을 이용한 결과에 비해 CN값과 유효우량이 더 높게 나타났고 삼각단위도로부터 유도한 정점의 유출량과 시간별 유량 관측값에 더 가까운 것으로 나타났다.

• Spatial Information Research
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• v.12 no.4 s.31
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• pp.371-382
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• 2004

Continuously Operating Reference Stations (CORS) provides GPS measurements to support high accuracy CPS positioning. The CORS improves GPS positioning productivity by eliminating the requirement for GPS users to operate two receivers. Previously, this is achieved by providing data from CORS to users in post-mission mode. However, the efficiency of the CORS will be maximized by upgrading it in real-time operation using RTK-GPS surveying because users can obtain centimeter-level accuracy in real-time without operating their own reference stations. In this research, authors extracted the arbitrary point's coordinate which is using GPS CORS data, now served in RINEX FORMAT via Internet, with observation network of the existing triangulation and GPS CORS data. And then, RTK GPS was performed with this arbitrary point as reference station.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.4
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• pp.133-141
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• 1991

The empirical method is used to integration adjustment for the coordinates revision of a national control point but the existing values are not to be changed or changed with small variation by suitable datum selection (for example, fixed points). This paper treats the modified weighted station parameter adjustment by quasi-observations, and the method used only variance elements of existing coordinates which is substituted for all covariance elements. The movement detection of unstable points and the junction adjustment of new networks are successfully executed by the method, in integration of new secondary networks to old-secondary-triangulation points which are in the absence of the original observations in Korea. The investigation results reveal that the accuracy of old-secondary-triangulation points is ${\pm}16^{{\prime}{\prime}}$(${\pm}0.08m$), which results from the densification of test network and the analyses of old survey specifications. and is ${\pm}2.3^{{\prime}{\prime}}$ in fixing of old-secondary-triangulation points.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.4 no.2
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• pp.77-87
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• 1986

As for the deformation measurement of structure, there are many controversial points in using the methods by the strain guage, inclinometer, bial guage, and geodetic method because of the difficulty of instrument setting and the problem in the degree of accuracy of the results as well as in the economical aspect. Therefore, to verify the superiority of the Close- Range Photogrammetry method for the structural deformation measurement, the result of load deformation on the model structure, which was made using the Close-Range Photogrammetry method was compard with the results which was made using the methods of dial guage, precision level, and triangulation. In addition to that, to consider the general problem which would happen when C. R. P method was applied to the practical structure. The elements of C. R. P method like camera rotation angle ($\psi$,$\omega$), exposure elevation (Z$_{L}$), and angle of inclined base line ($\theta$) were experimented, and their specificities were reconsidered. As a result, the application of C. R. P method to the general structure is expected to be increased not only in the aspect of accuracy but in the economical aspect.t.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.11 no.1
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• pp.37-45
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• 1993

We research on the coordinate transformation between Korean geodetic system and WGS 1984. We made the wide area an object of our research. This area covers the range of longitude $1^\circ$ 32'and latitude $1^\circ$ 7'and is four times wider than a first stage research published in 1992. For this research, we performed GPS observations at 10 control point (seven astrogeodetic points, three triangulation points) and eight banch marks nearby control points, and then transformed the coordinates of WGS 84 to Korean geodetic system using the 7 parameter method, Molodensky method and MRE method. From this test, we compared the precision of the coordinate transformation by each method and checked which method is more applicable to Korea. We could find that the precision by 7 parameter method is three times better than the other methods and that the coordinate transformation by 7 parameter method is possible with the precision of 0".017, 0".016, 0.329 m in latitude, longitude and height. We could check and correct the height blunder of the control points by the bench marks nearby control point. We also could find the precision of coordinate transformation is more improved by the correction of height blunder.t blunder.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.3
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• pp.55-63
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• 1996

In this paper, a vector control system is implemented to drive CRPWM inverter fed induction motor. The rotor flux is estimated using the rotor coordinates flux model and the stator coordinates ramp comparison controller is used as a current controller. The microcontroller 80C196 is used for the computation of the estimation of the rotor flux, the speed controller, the flux controller, the vector rotation, and the phase transformation The current controller is implemented using the analog circuit in order to reduce the burden of the microcontroller. For the proposed system, the digital simulation is performed to examine the feasibility and the superior characteristics of the current controller and the system transient response is verified through the experiment.