• Title/Summary/Keyword: 3D (3Dimensional)

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Evaluation of the repeatability and matching accuracy between two identical intraoral spectrophotometers: an in vivo and in vitro study

  • Kim, Hee-Kyung
    • The Journal of Advanced Prosthodontics
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    • v.10 no.3
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    • pp.252-258
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    • 2018
  • PURPOSE. The purpose of this study was to evaluate the repeatability and matching accuracy between two identical intraoral spectrophotometers. MATERIALS AND METHODS. The maxillary right central incisor, canine, and mandibular left central incisor of each of 30 patients were measured using 2 identical intraoral spectrophotometers with different serial numbers (EasyShade V). The color of each shade tab from 3 shade guides (VITA 3D-Master) was also determined with both devices. All measurements were performed by a single operator. Statistical analyses were performed to verify the repeatability, accuracy, and the differences between the devices with paired t-tests, one-way ANOVA, and intra-class correlation coefficients (ICCs) (${\alpha}=.05$). RESULTS. A high level of measurement repeatability (ICC>0.90) among $L^*$, $a^*$, and $b^*$ color components was observed within and between devices (P<.001). Intra-device matching agreement rates were 80.00% and 81.11%, respectively, while inter-device matching agreement rate was 51.85%. ANOVA revealed no significant different color values within each device, while paired t-test provided significant different color values between both devices. The CIEDE2000 color differences between both devices were $2.28{\pm}1.61$ ${\Delta}E_{00}$ for in-vivo readings. Regarding the clinical matching accuracy of both devices, ${\Delta}E_{00}$ values between teeth and matching shade tabs were $3.05{\pm}1.19$ and $2.86{\pm}1.02$, respectively. CONCLUSION. Although two EasyShade V devices with different serial numbers show high repeatability of CIE $L^*$, $a^*$, and $b^*$ measurements, they could provide different color values and shade for the same tooth.

An Evaluation Technique of Surface Roughness of Corroded Reinforcing Bar-in-Coils (코일철근의 표면 거칠기 물리량 평가 기술)

  • Roh, Young-Sook;Cho, Kang Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.10
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    • pp.6551-6557
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    • 2015
  • This paper discusses the surface roughness of corroded reinforcement rebar-in-coil focusing on the quantitative measurement technique using 3D scanner. Reinforcement rebar-in-coil was stacked in site for 0 day, 3 days, 7 days, 14 days and 21 days. And rebar-in-coil was corroded 0.04%, 0.3367%, 0.6157%, 0.7898%, and 1.1965% respectively. Using 3-dimensional scanner, each surface profile of reinforcement rebar-in-coil was established, and surface roughness was measured. Through the tests and analyses of corroded rebar-in-coil, the increase of fractal dimension for each rebar-in-coil was measured as 0.0216, 0.0235, 0.028, 0.0319, and 0.0455 for different stacked periods. Therefore, surface assessment technique using fractal dimension showed similar results with the actual corrosion rate.

Dynamic analysis of wind turbine wake (풍력 발전 터빈 후류의 동적 분석)

  • Um, Young Han;Kim, Yun Gu;Park, Sung Goon
    • Journal of the Korean Society of Visualization
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    • v.18 no.2
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    • pp.59-65
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    • 2020
  • Vertical axis wind energy systems including 3 and 4 blades are numerically investigated in a two-dimensional (2D) computational domain. The power coefficient (Cp) is adopted to measure the efficiency of the system and the effect of the rotating velocity on the power coefficient is analyzed for the two different systems. The rotating velocity varies from 30 rad/s to 90 rad/s, which corresponds to the tip speed ratio (T.S.R) of 0.5 to 1.5. The torque exerted on the blades is mainly determined by the aerodynamic force in the x-direction and maximized when the blade is positioned at around θ = 186°. The efficiency of the 4-blade system is higher than that of the 3-blade system within the tip speed ratio range between 0.5 and 0.67, besides where the 3-blade system shows a better performance. For the 3-blade system, the maximum efficiency is reached to 0.082 at the tip speed ratio of 1.083. The maximum efficiency of the 4-blade system is 0.071 at T.S.R. = 0.92. The velocity fields in the x-direction, pressure fields, and the vorticity magnitude are analyzed in detail for the optimal cases of the 3- and 4-blades systems, respectively.

Development of Image Guided 3D Localization Program for Stereotactic Brain Biopsy (뇌 정위 생검술을 위한 영상지원 3차원 국재 프로그램 개발)

  • Lee Do Heui;Lee Dong Joon
    • Progress in Medical Physics
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    • v.15 no.4
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    • pp.197-201
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    • 2004
  • Stereotactic brain biopsy using stereotactic head frame such as CRW (Radionics, USA) has demonstrated a precise lesion localizing accuracy. In this study, we developed the target point calculation program for brain lesion biopsy using CRW stereotactic head frame and designed a phantom for verify the new developed program. The phantom was designed to have capability to simulate clinical stereotactic brain biopsy. The phantom has 10 vertical rods whose diameters are 6mm and tip of each rods are 2mm. Each rod has different length, 150 mm x 4 ea, 130 mm x 4 ea, 110 mm x 2 ea. CT images were acquired with Simens CT scanner as continuous transverse slice, 1 mm thickness in a 25 cm field of view and stored in a dicom file as a 256 x 256 matrix. As a result, the developed new target localization program will be useful for planning and training in complicated 3 dimensional stereotactic brain biopsy.

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3-Dimensional Sequence Interpretation of Seismic Attributes in the Structurally Complex Area (복잡한 지질구조 지역에서의 3차원 탄성파 Attribute를 이용한 층서해석 사례)

  • Kim, Kun-Deuk
    • Geophysics and Geophysical Exploration
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    • v.2 no.3
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    • pp.149-153
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    • 1999
  • The study was performed as a part of 3-D exploration project of the South Con Son basin, where Korea National Oil Co. (KNOC) and SHELL Company are performing joint operation. In the structurally complex area, seismic facies or lap-out patterns, which are usually the tools for the conventional seismic stratigraphy developed by Exxon Group (Vail et at., 1977), are not easily identifiable. Therefore, stratigraphic informations are mainly extracted from seismic attribute maps of each sequence or systems tracts, and isopach maps in correlation with the stratigraphic information from the wells. The attribute maps of the sequence or systems tract boundaries and isopach map describe the variations of paleodepositional environments. The shape of the attribute maps of the boundaries is a reasonable description of the shape of the paleodepositional surface. With other maps such as isopach and structural maps, the variations of the parasequences in the systems tracts can be projected using the surface attribute maps. The reflection intensity attribute at each sequence or system tract boundary can be related to lithology, facies or porosity distributions. The azimuth attribute of source rock sequence can be used to identify the hydrocarbon migration patterns into the prospects. The overall risks of reservoir rocks, cap rocks, structure and hydrocarbon migrations were computed using the results of the study.

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Study of Tolerance Suitability of Door Operation Mechanism on Mobile Air Handing Unit Using 3-DCS Analysis (3-DCS를 이용한 자동차 공기 분배장치의 도아 구동 기구의 공차 적합성 분석에 대한 연구)

  • Kim, Jongsu;Lee, Daewoong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.5
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    • pp.527-537
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    • 2016
  • Recent automakers are trying to be more precise with the dimension check and moving parts to guarantee high quality and satisfy customer requirements. The aim of this paper is to investigate the design tolerance suitability of door operating mechanism linked arms, lever, and cam-shaft in a mobile air handling unit. These parts are complicated because doors, arms, lever and cam-shaft are connected nonlinearly in 3D. The current tolerance analysis method poses problems in design analysis because the moving doors are reasonably suitable for the AHU function. The 3-DCS analysis method provided useful results not only in establishing the inspection criteria for the quality control of products but also in enabling economical production. As a result, the vent door had $1.62^{\circ}{\sim}1.72^{\circ}$ and the defrost door had $0.84^{\circ}{\sim}0.9^{\circ}$ for the directly connected arms operating-type. For the lever connected arm operating-type, the foot door had $2.0^{\circ}{\sim}2.24^{\circ}$ tolerance, while the tolerance values satisfied the air flow volume distribution rate criteria in the AHU. Finally, the results have confirmed the design's tolerance suitability by using 3-DCS analysis at the early design stages. Reliability can be achieved by analyzing accumulated tolerance during the sub-parts assembly process and the moving mechanism linked especially by arms, lever, and cam-shaft.

Implementation of theVerification and Analysis System for the High-Resolution Stereo Camera (고해상도 다기능 스테레오 카메라 지상 검증 및 분석 시스템 구현)

  • Shin, Sang-Youn;Ko, Hyoungho
    • Korean Journal of Remote Sensing
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    • v.35 no.3
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    • pp.471-482
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    • 2019
  • The mission of the high-resolution camera for the lunar exploration is to provide 3D topographic information. It enables us to find the appropriate landing site or to control accurate landing by the short distance stereo image in real-time. In this paper, the ground verification and analysis system using the multi-application stereo camera to develop the high-resolution camera for the lunar exploration are proposed. The mission test items and test plans for the mission requirement are provided and the test results are analyzed by the ground verification and analysis system. For the realistic simulation for the lunar orbiter, the target area that has similar characteristics with the real lunar surface is chosen and the aircraft flight is planned to take image of the area. The DEM is extracted from the stereo image and compose three dimensional results. The high-resolution camera mission requirements for the lunar exploration are verified and the ground data analysis system is developed.

Experimental Analysis for Core Losses Prediction in Electric Machines by Using Soft Magnetic Composite (복합 연자성 소재의 전동기 코어손실 예측을 위한 실험적 분석)

  • Park, Eui-Jong;Kim, Yong-Jae
    • The Journal of the Korea institute of electronic communication sciences
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    • v.16 no.3
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    • pp.471-476
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    • 2021
  • Soft magnetic composite (SMC) materials based on powder metallurgy have a number of advantages over the conventional electrical steel sheets commonly used in electric machines. Thus, technologies related to these materials have shown significant improvement in recent years. In general, SMCs are magnetically isotropic owing to the shape of the powder, which makes them suitable for the construction of electric machines with three-dimensional flux and complex structures. However, the materials with isotropic magnetic properties (such as SMCs) have complex vector hysteresis; thus, it is very difficult to predict accurate loss properties. Therefore, we manufactured ring-type specimens of electrical steel sheets and SMC, which analyzed their magnetic properties according to the specimen size, and performed the electromagnetic field analysis of a high-speed permanent magnet (PM) motor driven at 800 Hz or higher using the measured magnetic information to compare the core loss of the motor. The reliability of this paper has been verified by measuring the efficiency after manufacturing the motor.

Development of immersive flood routing model using three-dimensional virtual reality visualization (3차원 가상현실 시각화를 활용한 몰입형 홍수추적 모형 개발)

  • Son, Sangyoung;Hwang, Sooncheol
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.96-96
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    • 2022
  • 가상현실 (Virtual Reality, VR) 기술은 3차원 가상공간 내에서의 높은 몰입감에 기반한 체험을 바탕으로 다양한 분야에서 활용되고 있다. 소방훈련이나 태풍, 지진 등 재해 대응훈련과 같이 인명피해의 위험이 있는 재해에 대한 VR 기술을 활용한 방재교육은 위험성을 동반하지 않으면서도 현장감에 기반한 높은 교육적 효과를 창출할 수 있다. 한국전자통신연구원에서는 VR 기술을 이용하여 소방훈련을 위한 실감 소방훈련 시뮬레이터를 개발한 바 있으며 목동재난체험관에서는 홍수, 태풍, 지진 등 다양한 재해에 대한 안전교육을 위한 자연재해 가상현실체험을 운영하고 있다. 이외에도 전국 지자체 및 교육청에서는 방재교육을 목적으로 VR 기술을 활용하고 있다. 그러나 기존의 VR을 활용한 수재해 방재교육은 범람의 수리학적 특성과 함께 수해지의 지형적 특성을 적절히 반영하지 못하는 단점을 가지고 있다. 이는 방재교육이나 경각심을 부각하는 데엔 효과적이나 실질적인 방재 가이드라인을 제시하는 데엔 한계가 있다. 본 연구는 몰입형 파랑해석모형인 Celeris Base를 기반으로 3차원 가상현실 시각화를 활용한 수리학적 홍수추적 모형을 개발하였다. 3차원 가상현실 시각화는 Unity3D를 이용하여 모의환경 내에 구현되었다. 강우-유출 과정의 수리학적 해석을 위해 동수역학 수치모형의 연속방정식 내에 강우와 침투에 대한 항을 추가하였다. 침투모형으로는 Horton 모형, Green-Ampt 모형과 함께 사면의 기울기를 고려한 Green-Ampt 모형을 적용하였다. 실제 유역에서의 홍수추적 모의결과는 관측값과 비교적 잘 일치함을 확인하였다. 개발된 모형은 VR 방재교육을 통해 일반인의 수재해 대응능력 향상에 기여함과 동시에 정확성 높은 홍수추적 모의결과에 기반한 홍수대책 마련에도 활용 가능할 것으로 기대된다.

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High-Resolution Contrast-Enhanced 3D-Spoiled Gradient-Recalled Imaging for Evaluation of Intracranial Vertebral Artery and Posterior Inferior Cerebellar Artery in Lateral Medullary Infarction (고해상도 조영증강 삼차원 회손기울기 회상 영상을 이용한 측면연수경색 환자의 두개내 척추동맥 및 뒤아래소뇌동맥 평가)

  • Yoon, Youngno;Ahn, Sung Jun;Suh, Sang Hyun;Park, Ah Young;Chung, Tae-Sub
    • Investigative Magnetic Resonance Imaging
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    • v.18 no.1
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    • pp.17-24
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    • 2014
  • Purpose : To determine whether high-resolution contrast-enhanced three dimensional imaging with spoiled gradient-recalled sequence (HR-CE 3D-SPGR) plays a meaningful role in the assessment of intracranial vertebral artery (ICVA) and posterior inferior cerebellar artery (PICA) in lateral medullary infarction (LMI). Materials and Methods: Twenty-five patients confirmed with LMI were retrospectively enrolled with approval by the IRB of our institute, and 3T MRI with HR-CE 3D-SPGR and contrast-enhanced magnetic resonance angiography (CE-MRA) were performed. Two radiologists who were blinded to clinical information and other brain MR images including diffusion weighted image independently evaluated arterial lesions in ICVA and PICA. The demographic characteristics, the area of LMI and cerebellar involvement were analyzed and compared between patients with arterial lesion in ICVA only and patients with arterial lesions in both ICVA and PICA on HR-CE 3D-SPGR. Results: Twenty-two of twenty-five LMI patients had arterial lesions in ICVA or PICA on HR-CE 3D SPGR. However twelve arterial lesions in PICA were not shown on CE-MRA. Concurrent cerebellar involvement appeared more in LMI patients with arterial lesion in ICVA and PICA than those with arterial lesion in ICVA alone (p = 0.069). Conclusion: HR-CE 3D-SPGR can help evaluate arterial lesions in ICVA and PICA for LMI patients.