• Title/Summary/Keyword: Coordinate System

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A Study on the Unsteady Flow Characteristics of a Delta Wing by 3-D Stereo PIV (3-D Stereo PIV에 의한 비정상 델타윙 유동특성에 대한 연구)

  • Kim, Beom-Seok;Lee, Hyun;Kim, Jeong-Hwan;Lee, Young-Ho
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1672-1677
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    • 2004
  • Leading edge extension(LEX) in a highly swept shape applied to a delta wing features the modem air-fighters. The LEX vortices generated upon the upper surface of the wing at high angle of attack enhance the lift force of the delta wing by way of increased negative suction pressure over the surfaces. The present 3-D stereo PIV includes the Identification of 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system, removal of error vectors by a statistical method followed by a continuity equation criterion and so on. A delta wing model with or without LEX was immersed in a circulating water channel. Two high-resolution, high-speed digital cameras($1280pixel{\times}1024pixel$) were used to allow the time-resolved animation work. The present dynamic stereo PIV represents the complicated vortex behavior, especially, in terms of time-dependent characteristics of the vortices at given measuring sections. Quantities such as three velocity vector components, vorticity and other flow information can be easily visualized via the 3D time-resolved post-processing to make the easy understanding of the LEX effect or vortex emerging and collapse which are important phenomena occurring in the field of delta wing aerodynamics.

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Development of Monte Carlo Simulation Code for the Dose Calculation of the Stereotactic Radiosurgery (뇌 정위 방사선수술의 선량 계산을 위한 몬테카를로 시뮬레이션 코드 개발)

  • Kang, Jeongku;Lee, Dong Joon
    • Progress in Medical Physics
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    • v.23 no.4
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    • pp.303-308
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    • 2012
  • The Geant4 based Monte Carlo code for the application of stereotactic radiosurgery was developed. The probability density function and cumulative density function to determine the incident photon energy were calculated from pre-calculated energy spectrum for the linac by multiplying the weighting factors corresponding to the energy bins. The messenger class to transfer the various MLC fields generated by the planning system was used. The rotation matrix of rotateX and rotateY were used for simulating gantry and table rotation respectively. We construct accelerator world and phantom world in the main world coordinate to rotate accelerator and phantom world independently. We used dicomHandler class object to convert from the dicom binary file to the text file which contains the matrix number, pixel size, pixel's HU, bit size, padding value and high bits order. We reconstruct this class object to work fine. We also reconstruct the PrimaryGeneratorAction class to speed up the calculation time. because of the huge calculation time we discard search process of the ThitsMap and used direct access method from the first to the last element to produce the result files.

Molecular Geometries and Electronic Structures of Methyl Pyropheophorbide-a and (Cationic) Tropolonyl Methyl Pyropheophorbides: DFT Calculation

  • Kim, Na-Ri;Kim, Su-Jin;Kim, Jin-Dong;Huh, Do-Sung;Shim, Young-Key;Choe, Sang-Joon
    • Bulletin of the Korean Chemical Society
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    • v.30 no.1
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    • pp.205-213
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    • 2009
  • This study reports on the geometry optimizations and electronic structure calculations for methyl pyropheophorbide (MPPa), tropolonyl methyl pyropheophorbides (TMPPa, ITMPPa), and cationic tropolonyl methyl pyropheophorbides ($TMPPa^+{{\cdot}BF_4}^-,\;ITMPPa^+{{\cdot}BF_4}^-,\;TMPPa^+,\;and\;ITMPPa^+$) using Local Spin Density Approximation (LSDA/ 6-31G*) and the Restricted Hatree-Fock (RHF/6-31G*) level theory. From the calculated results, we found that substituted cationic tropolonyl groups have larger structural effects than those of substituted neutral tropolonyl groups. The order of structural change effects is $ITMPPa^+ > ITMPPa^+{{\cdot}BF_4}^-$ > ITMPPa, as a result of the isopropyl group. Because it is an electron-releasing group, the substituted isopropyl group electronic effect on a 3-position tropolone increases the Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbital (HOMO-LUMO) energy gap. It was constituted that the larger the cationic characters of these photosensitizers, the smaller the HOMOLUMO band gaps are. The orbital energies of the cationic systems and the ions are stronger than those of a neutral system because of a strong electrostatic interaction. However, this stabilization of orbital energies are counteracted by the distortion of chlorin macrocycle, which results in a large destabilization of chlorin-based compound HOMOs and smaller destabilization of LUMOs as shown in TMPPa (ITMPPa), $TMPPa^+{{\cdot}BF_4}^- (ITMPPa^+{{\cdot}BF_4}^-),\;and\;TMPPa^+\;(ITMPPa^+)$ of Figure 6 and Table 6-7. These results are in reasonable agreement with normal-coordinate structural decomposition (NSD) results. The HOMO-LUMO gap is an important factor to consider in the development of photodynamic therapy (PDT).

Microsoft Kinect-based Indoor Building Information Model Acquisition (Kinect(RGB-Depth Camera)를 활용한 실내 공간 정보 모델(BIM) 획득)

  • Kim, Junhee;Yoo, Sae-Woung;Min, Kyung-Won
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.4
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    • pp.207-213
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    • 2018
  • This paper investigates applicability of Microsoft $Kinect^{(R)}$, RGB-depth camera, to implement a 3D image and spatial information for sensing a target. The relationship between the image of the Kinect camera and the pixel coordinate system is formulated. The calibration of the camera provides the depth and RGB information of the target. The intrinsic parameters are calculated through a checker board experiment and focal length, principal point, and distortion coefficient are obtained. The extrinsic parameters regarding the relationship between the two Kinect cameras consist of rotational matrix and translational vector. The spatial images of 2D projection space are converted to a 3D images, resulting on spatial information on the basis of the depth and RGB information. The measurement is verified through comparison with the length and location of the 2D images of the target structure.

Preparation of Anatase TiO2 Thin Films with (OiPr)2Ti(CH3COCHCONEt2)2 Precursor by MOCVD

  • Bae, Byoung-Jae;Lee, Kwang-Yeol;Seo, Won-Seok;Miah, Md. Arzu;Kim, Keun-Chong;Park, Joon T.
    • Bulletin of the Korean Chemical Society
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    • v.25 no.11
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    • pp.1661-1666
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    • 2004
  • The reaction of titanium tetraisopropoxide with 2 equiv of N,N-diethyl acetoacetamide affords Ti($O^iPr)_2(CH_3COCHCONEt_2)_2$ (1) as colorless crystals in 80% yield. Compound 1 is characterized by spectroscopic (Mass and $^1H/^{13}C$ NMR) and microanalytical data. Molecular structure of 1 has been determined by a single crystal X-ray diffraction study, which reveals that it is a monomeric, cis-diisopropoxide and contains a six coordinate Ti(IV) atom with a cis($CONEt_2$), trans($COCH_3$) configuration (1a) in a distorted octahedral environment. Variable-temperature $^1H$ NMR spectra of 1 indicate that it exists as an equilibrium mixture of cis, trans (1a) and cis, cis (1b) isomers in a 0.57 : 0.43 ratio at -20$^{\circ}C$ in toluene-$d_8$ solution. Thermal properties of 1 as a MOCVD precursor for titanium dioxide films have been evaluated by thermal gravimetric analysis and vapor pressure measurement. Thin films of pure anatase titanium dioxide (after annealing above 500$^{\circ}C$ under oxygen) have been grown on Si(100) with precursor 1 in the substrate temperature range of 350- 500$^{\circ}$ using a bubbler-based MOCVD method.

Population Change and Future Direction of Population Policy in Korea (한국의 인구현황과 정책방향)

  • 이시백
    • Korea journal of population studies
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    • v.5 no.1
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    • pp.4-16
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    • 1982
  • The Korean Population Control Program has been implementing under the jurisdiction of the Ministry of Health and Social Affairs through an existing network of health centers. This arrangement was successful in bringing population growth down to targeted level by the end of the Fourth Five Year Economic Planning, 1981. It is expected, however, that future goal will be harder to reach due to difficulty of reducing traditional family size norms further and to the projected increasing the number of eligible couples as the past Korean war baby boom generation enters the reproductive activity in the next few years. The recognition of the need for modification of population policy is increasing. The 1980 census shows that the total number of population reached approximately 38.5 million with 1.57 per cent of the growth rate. It was projected that the size of Korean Population will reach around 42 million and 51 million in 1986 and 2000 respectively. Furthermore, there is some argument as to whether decline in the birth rate in Korea is too slow to meet government target. Hence, a new development of population policy and greatly increased amount of effort will be needed in order to achieve Zero Population Growth Rate before the year 2050. The development of future national population policy and its related area are recommended as follow: 1. It is highly recommended that the population planning law governing both vital events of birth and death and population migration should be legislated. 2. The National Population Policy Council, Chaired by Deputy Prime Minister should be activated to implement and coordinate population program within ministries. 3. Responsible organization of population and family planning program should be established as a Bureau unit at central government level. 4. For the improvement of national vital registration, an existing system should be studied and developed.

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The Parameter Identification of Tidal Model on The Boundary-Fitted Coordinates (Boundary-Fitted 좌표계로 변환한 2차원조석모형의 매개변수 동정)

  • 김경수;이재형
    • Water for future
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    • v.23 no.3
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    • pp.319-328
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    • 1990
  • The Parameter Identification of 2-demensional estuarine model was carried out using new output ADI-FDM numerical semi-implicit schem transformed in boundary fitted(BF) - coordinate. The hydrodynamic equations which is coupled with the transport equations were used as basic equations in the model. Thompson's equations were used to transform governing equations into rectangular plane equations and his elliptic grid generation scheme was used to generate curvilinear grid system. in BF - coordinates. The parameters to be identified are friction coefficient and disperse coefficient embedded in the governing equations. The numerical output scheme is tidally averaged salinity model in BF - coordinates. The algorithm to optimize norm of error between observations and calculations is the influence coefficinet algorithm associated with least square criterion. The lumped model is conssidered in identification. This paper was concetrated on checking whether the new output scheme might be useful to identify parameters in estuarine salinity model or not. The proposed method was tested through experimental application with hypothetical simple model. The result of the test shows that the proposed method can be used for parameter identification in estuarine model.

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The Analysis of Road Alignement and Construction GSIS Using RTK GPS and TS (RTK-GPS와 TS를 이용한 도로선형분석 및 GSIS 구축)

  • 장상규;홍순헌;김가야
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.21 no.4
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    • pp.293-299
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    • 2003
  • In the future, the design of road should be convenient in using of high-technology information and it needs the design of alignment that is able to make the maximum vehicles inducement function appropriated for CNS(Car Navigation System). So it needs to analysis appropriately the alignment of road for the improvement design of road which is established and to make the design of road and the coordinate of the main points. Therefore, this research had acquired the road data by RTK-GPS to accurate the analysis of road alignment and compared with Total Station. As the result, we could acquire the design source of the road alignment using RTK-GPS. Also, it was estimated the accuracy after comparing the design with RTK-GPS coordinates. We made an analysis of the degree of slant or the ups and downs of surface. We made an analysis of three dimensional visual information which was included in GSIS concept and estimated the accuracy. Finally, we analyzed the earth volume calculation by comparing with Total Station.

Geometric Correction of IKONOS-2 Geo-level Satellite Imagery Using LiDAR Data - Using Linear Features as Registration Primitivess (항공레이저측량 자료를 활용한 IKONOS-2 위성영상의 기하보정에 관한 연구 - 선형요소를 기하보정의 기본요소로 활용하여)

  • Lee, Jae-Bin;Kim, Yong-Min;Lee, Hyo-Seong;Yu, Ki-Yun;Kim, Yong-Il
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.25 no.3
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    • pp.183-190
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    • 2007
  • To make use of surveying data obtained from different sensors and different techniques, it is a pre-requite step that register them in a common coordinate system. For this purpose, we developed methodologies to register IKONOS-2 Satellite Imagery using LiDAR(Light Detection And Ranging) data. To achieve this, conjugate features from these data should be extracted in advance. In this study, linear features are chosen as conjugate features. Then, to register them, observation equations are established from similarity measurements of the extracted features and the results was evaluated statistically. The results clearly demonstrate that the proposed algorithms are appropriate to register these data.

Rainfall Estimation by X-band Marine Radar (X밴드 선박용 레이더를 이용한 강우 추정)

  • Kim, Kwang-Ho;Kwon, Byung-Hyuk;Kim, Min-Seong;Kim, Park-Sa;Yoon, Hong-Joo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.13 no.4
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    • pp.695-704
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    • 2018
  • The rainfall cases were identified by rainfall estimation techniques which were developed by using X - band marine radar. A digital signal converter was used to convert the signal received from the marine radar into digital reflectivity information. The ground clutter signal was removed and the errors caused by beam attenuation and beam volume changes were corrected. The reflectivity showed a linear relationship with the rain gauge rainfall. Quantitative rainfall was estimated by converting the radar signal into an cartesian coordinate system. When the rainfall was recorded more than $5mm\;hr^{-1}$ at three automatic weather stations, the rain cell distribution on the marine radar was consistent with that of the weather radar operated by Korea meteorological Adminstration.