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  • Title/Summary/Keyword: Three-dimensional Model

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Empirical Comparisons of Disparity Measures for Partial Association Models in Three Dimensional Contingency Tables

  • Jeong, D.B.;Hong, C.S.;Yoon, S.H.
    • Communications for Statistical Applications and Methods
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    • v.10 no.1
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    • pp.135-144
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    • 2003
  • This work is concerned with comparison of the recently developed disparity measures for the partial association model in three dimensional categorical data. Data are generated by using simulation on each term in the log-linear model equation based on the partial association model, which is a proposed method in this paper. This alternative Monte Carlo methods are explored to study the behavior of disparity measures such as the power divergence statistic I(λ), the Pearson chi-square statistic X2, the likelihood ratio statistic G2, the blended weight chi-square statistic BWCS(λ), the blended weight Hellinger distance statistic BWHD(λ), and the negative exponential disparity statistic NED(λ) for moderate sample sizes. We find that the power divergence statistic I(2/3) and the blended weight Hellinger distance family BWHD(1/9) are the best tests with respect to size and power.

Comoutation of Currents Driven by a Steady Uniform Wind Stress on the East China Sea using a Three-dimensional Numerical Model (三次元數値모델을 使용한 東支那海의 定常均一風의 應力에 의한 海流의 算定)

  • Choi, Byung Ho
    • 한국해양학회지
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    • v.19 no.1
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    • pp.36-43
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    • 1984
  • A three-dimensional hydrodynamical numerical model of the Yellow Sea and the East China Sea is formulated having irregular coastal boundaries and non-uniform depth distribution represntative of nature. The developed model is used to derive the currents driven by a steady uniform wind stress on the Yellow Sea and the East China Sea. Numerical experiments have been performed with the model to determine the response of the shelf to stationary wind stress fields suddenly imposed on the shelf for wind directions of NW and SW winds and wind stress of 1.6dyn/cm2. The dynamical feature of the derived circulation are presented and discussed.

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Three-Dimensional Numerical Model for Flow with Silt Protector (오탁방지막이 설치된 3차원 흐름 수치모델)

  • Hong, Nam-Seeg;Kim, Ga-Ya;Kang, Yoon-Koo
    • Journal of Ocean Engineering and Technology
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    • v.22 no.3
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    • pp.1-7
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    • 2008
  • In this study, a mathematical model for flaw with silt protector is proposed that adds a second-order energy loss term in the momentum equation. The three-dimensional numerical model was developed based on mathematical models and verified through comparison with flume test results. Loss coefficients were evaluated through the flume tests and applied to the numerical model. It was found through the investigation of various example cases that the downstream flow pattern was affected mainly by penetration of the silt curtain, not by the approach velocity, and also that the blocking effect of velocity was increased by the increase in mesh density of the silt curtain, below a certain mesh density. The blocking effect did not increase further above a certain mesh density.

Simulation of corroded RC structures using a three-dimensional irregular lattice model

  • Kim, Kunhwi;Bolander, John E.;Lim, Yun Mook
    • Structural Engineering and Mechanics
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    • v.41 no.5
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    • pp.645-662
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    • 2012
  • Deteriorative effects of steel corrosion on the structural response of reinforced concrete are simulated for varying degrees of corrosion. The simulation approach is based on a three-dimensional irregular lattice model of the bulk concrete, in which fracture is modeled using a crack band approach that conserves fracture energy. Frame elements and bond link elements represent the reinforcing steel and its interface with the concrete, respectively. Polylinear stress-slip properties of the link elements are determined, for several degrees of corrosion, through comparisons with direct pullout tests reported in the literature. The link properties are then used for the lattice modeling of reinforced concrete beams with similar degrees of corrosion of the main reinforcing steel. The model is successful in simulating several important effects of steel corrosion, including increased deflections, changes in flexural cracking behavior, and reduced yield load of the beam specimens.

A study on the 3-D CNC cutting planning and simulation by Z-Map model (Z-Map모델을 이용한 3차원 CNC가공계획 및 절삭시뮬레이션에 관한 연구)

  • Song, Soo-Yong;Kim, Seok-Il
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.5
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    • pp.115-121
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    • 1996
  • Recently, the Z-Map model has been used widely to represent the three dimensional geometric shape and to achieve the cross-section and point evaluation of the shape. In this paper, the CNC cutting planning and simulation modules for product with three dimensional geometric shape are realized based on the Z-Map model. The realized system has the various capabilities related to the automatic generation of tool path for the rough and finish cutting processes, the automatic elimination of overcut, the automatic generation of CNC program for a machining center and the cutting simulation. Especially, the overcut-free tool path is obtained by using the CL Z-Map models which are composed of the offset surfaces of the geometric shape of product.

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A Study on the Point Placement Task of Robot System Based on the Vision System (비젼시스템을 이용한 로봇시스템의 점배치실험에 관한 연구)

  • Jang, Wan-Shik;You, Chang-gyou
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.8
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    • pp.175-183
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    • 1996
  • This paper presents three-dimensional robot task using the vision control method. A minimum of two cameras is required to place points on end dffectors of n degree-of-freedom manipulators relative to other bodies. This is accomplished using a sequential estimation scheme that permits placement of these points in each of the two-dimensional image planes of monitoring cameras. Estimation model is developed based on a model that generalizes known three-axis manipulator kinematics to accommodate unknown relative camera position and orientation, etc. This model uses six uncertainty-of-view parameters estimated by the iteration method.

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Moving Temperature Profile Method for Efficient Three-Dimensional Finite Element Welding Residual Stress Analysis for Large Structures (대형구조물의 효율적 3차원 용접잔류응력해석을 위한 새로운 이동 온도 프로파일 방법)

  • Cheol Ho Kim;Jae Min Gim;Yun Jae Kim
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.19 no.2
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    • pp.75-83
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    • 2023
  • For three-dimensional finite element welding residual stress simulation, several methods are available. Two widely used methods are the moving heat source model using heat flux and the temperature boundary condition model using the temperature profile of the welded beads. However, each model has pros and cons in terms of calculation times and difficulties in determining welding parameters. In this paper, a new method using the moving temperature profile model is proposed to perform efficiently 3-D FE welding residual stress analysis for large structures. Comparison with existing experimental residual stress measurement data of two-pass welding pipe and SNL(Sandia National Laboratories) mock-up canister shows the accuracy and efficiency of the proposed method.

A Study on the Supportive Stiffness in Transitional Zones through Moving Load-Based Three-Dimensional Modeling (이동하중과 3차원 모델링을 통한 접속부 지지강성연구)

  • Woo, Hyeun-Joon;Lee, Seung-Ju;Kang, Yun-Suk;Cho, Kook-Hwan
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1542-1549
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    • 2011
  • The Transitional zone between bridge abutment and earthwork is one of the representative vulnerable zones in railway where differential settlements may take place due to the different supportive stiffness. Although transitional zones are managed with stricter standards than those of the other earthwork zones either in the design and construction stages, it is very difficult to prevent differential settlement perfectly. A three-dimensional numerical analyses were performed by applying train moving load in this study. The analytical model including abutments and earthwork zones was constituted with rail, sleepers, track concrete layer (TCL), hydraulic stabilized base (HSB), reinforced road bed, and road bed using railway and road base structure. The clamp connecting the rail and sleeper were also modeled as the element with spring coefficient. The train wheel is modeled in the actual size and moved on the rail with 300 km/hr speed. The deformation characteristics at each point of the rail and the ground were considered in detail when moving the train wheel. The analysis results were compared with those from the two-dimensional analysis without considering moving load. The research results show that displacement and stress were greater in the three-dimensional analysis than in other analyses, and the three-dimensional analysis with moving load should be performed to evaluate railway performance.

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Measurement Method for Fine 6-DOF Displacement of Rigid Bodies (강체의 6자유도 미소 변위 측정)

  • Park, Won-Shik;Cho, Hyung-Suck
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.3
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    • pp.208-219
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    • 2002
  • A novel measurement method to obtain the 6-DOF motions of arbitrary rigid bodies is proposed in this paper. The method adopts a specially fabricated mirror called 3-facet mirror, which looks like a triangular pyramid haying an equilateral cross-sectional shape. The mirror is mounted on the objects to be measured, illuminated by a laser beam having circular profile, and reflects the laser beam in three different directions. Three PSDs(position sensitive detector) detect the three beams reflected by the mirror, respectively. From the signals of the PSDs, we can calculate the 3-dimensional position and orientation of the 3-facet mirror, and thus enabling us to determine the 3-dimensional position and orientation of the objects. In this paper, we model the relationship between the 3-dimensional position and orientation of an object in motion and the outputs of three PSDs. A series of experiments are performed to demonstrate the effectiveness and accuracy of the proposed method. The experimental results show that the proposed sensing system can be an effective means of obtaining 3-dimensional position and orientation of arbitrary objects and provide resonable measurement accuracy.

Revision of 1/1,000 digital Map for Application of 3Dimensional Geospatial Data (1/1,000 수치지도의 수정을 위한 3차원 공간정보의 활용 방안)

  • Lee, Hyunjik
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.32 no.2
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    • pp.77-86
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    • 2014
  • As raster-based high quality and resolution spatial information has appeared, 1/1,000 digital map lost either its recognition or uses because of insufficient new modified and updated information. Therefore, this study analyzed the linkage between three-dimensional spatial information and 1/1,000 digital map, and also suggested a modification plan of 1/1,000 digital map, made by three-dimensional spatial information. In fact, some area of Incheon and Busan were presented with the modification plan of 1/1,000 digital map as three-dimensional trial models. These trials reflected possibilities of modification by qualitative and quantitative analysis of 1/1,000 digital map, using three-dimensional object model.