• Title/Summary/Keyword: Three-dimensional approach

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삼차원 변이 공간을 이용한 가변윈도우법 (A Variable Window Method with Three-Dimensional Disparity Space)

  • 김경범;이홍서
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.284-287
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    • 2003
  • Previous stereo methods doesn't deal effectively with depth discontinuity due to inevitable window-based problems, and so give inaccurate and noisy matching results in areas with steep disparity variations. In this paper. a variable window approach is presented to estimate accurate, detailed and smooth disparities with three-dimensional disparity space. It makes the smoothing of depth discontinuity reduced by evaluating corresponding correlation values and intensity gradient-based similarity in the space. In addition, it devises the novel arbitrarily-shaped variable window to treat with disparity variations of various structure shapes. We show how our results improve on those of closely related techniques for accuracy, robustness. matching density and computing speed.

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1단 터빈에서 축간격 변화가 비정상 이차유동 및 성능에 미치는 영향 (The effects of axial spacing on the unsteady secondary and performance in one-stage axial turbine)

  • 박준영;백제현
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2002년도 학술대회지
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    • pp.537-540
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    • 2002
  • Flow through turbomachinery has a very complex structure and is intrinsically unsteady. Especially, recent design trend to turbomachinery with short axial spacing makes the flow extremely complex due to the interaction between stator and rotor. Therefore, it is very necessary to clearly understand the complex flow structure to obtain the high efficiency turbomachinery. So, in this paper, the effects of axial spacing on the unsteady secondary flow performance in the one stage turbine are investigated by three-dimensional unsteady flow analysis. The three-dimensional solver is parallelized using domain decomposition and Message Passing Interface(MPI) standard to overcome the limitation of memory and the CPU time in three-dimensional unsteady calculation. A sliding mesh interface approach has been implemented to exchange flow information between blade rows.

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3차원배치설계에 대한 어닐링법의 적용 (Application of the Annealing Method to the Three Dimensional Layout Design)

  • 장승호;최명진
    • 한국시뮬레이션학회논문지
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    • 제10권2호
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    • pp.1-14
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    • 2001
  • The layout design of component plays an important role in the design and usability of many engineering products. The Engineering artifacts of today are becoming increasingly complicated. The simulated annealing method has been applied effectively to the layout and packing problems of wafer. The main characteristics of simulated annealing method is that an optimum can be obtained from the many local optimums by controlling the temperature and introducing the statistic flickering. The objective of this study is to suggest a method to apply the simulated annealing method to the three dimensional layout design of submergible boat which has multiple constraint conditions and evaluation criteria. We describe an approach to define cost function, constraints and generate layouts using a computer. In this research three dimensional LAYout Design Optimization Program(LAYDOP ver.2) has been developed. The layout result(the total value of evaluation criteria) designed by a human layout expert has been improved by 31.0% using this program.

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부유식 해양도시의 동적응답특성 (Dynamic Response Characteristics of a Floating Ocean City in Waves)

  • 구자삼;홍석원
    • 한국해양공학회지
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    • 제8권2호
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    • pp.80-92
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    • 1994
  • The dynamic response characteristics of a floating ocean city are examined for presenting the basic data for the design of huge offshore structures supported by a large number of floating bodies in waves. The numerical approach which is accurate in linear system is based on combination of a three dimensional source distribution method, wave interaction theory and the finite element method of using the space frame element. The hydrodynamic interactions among the floating bodies are taken into account in their exact form within the context of linear potential theory in the motion and structural analysis. The method is applicable to an arbitrary number of three dimensional bodies having any individual body geometries and geometrical arrangement with the restriction that the circumscribed, bottom-mounted. Imaginary vertical cylinder for each body does not contain any part of the other body. The validity of this procedure was verified by comparing with experimental results obtained in the literature.

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FracSys와 UDEC을 이용한 사면 파괴 양상 분석 통계적 절리망 생성 기법 및 Monte Carlo Simulation을 통한 사면 안정성 해석

  • 김태희;최재원;윤운상;김춘식
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2002년도 봄 학술발표회 논문집
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    • pp.651-656
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    • 2002
  • In general, the most important problem in slope stability analysis is that there is no definite way to describe the natural three-dimensional Joint network. Therefore, the many approaches were tried to anlayze the slope stability. Numerical modeling approach is one of the branch to resolve the complexity of natural system. UDEC, FLAC, and SWEDGE are widely used commercial code for the purpose on stability analysis. For the purpose on the more appropriate application of these kind of code, however, three-dimensional distribution of joint network must be identified in more explicit way. Remaining problem is to definitely describe the three dimensional network of joint and bedding, but it is almost impossible in practical sense. Three dimensional joint generation method with random number generation and the results of generation to UDEC have been applied to settle the refered problems in field site. However, this approach also has a important problem, and it is that joint network is generated only once. This problem lead to the limitation on the application to field case, in practical sense. To get rid of this limitation, Monte Carlo Simulation is proposed in this study 1) statistical analysis of input values and definition of the applied system with statistical parameter, 2) instead of the consideration of generated network as a real system, generated system is just taken as one reliable system, 3) present the design parameters, through the statistical analysis of ouput values Results of this study are not only the probability of failure, but also area of failure block, shear strength, normal strength and failure pattern, and all of these results are described in statistical parameters. The results of this study, shear strength, failure area, pattern etc, can provide the direct basement on the design, cutoff angle, support pattern, support strength and etc.

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3-D Vibration analysis of FG-MWCNTs/Phenolic sandwich sectorial plates

  • Tahouneh, Vahid
    • Steel and Composite Structures
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    • 제26권5호
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    • pp.649-662
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    • 2018
  • In this study, based on the three-dimensional theory of elasticity, free vibration characteristics of sandwich sectorial plates with multiwalled carbon nanotube-(MWCNT)-reinforced composite core are considered. Modified Halpin-Tsai equation is used to evaluate the Young's modulus of the MWCNT/epoxy composite samples by the incorporation of an orientation as well as an exponential shape factor in the equation. The exponential shape factor modifies the Halpin-Tsai equation from expressing a straight line to a nonlinear one in the MWCNTs wt% range considered. In this paper, free vibration of thick functionally graded sandwich annular sectorial plates with simply supported radial edges and different circular edge conditions including simply supported-clamped, clamped-clamped, and free-clamped is investigated. A semi-analytical approach composed of two-dimensional differential quadrature method and series solution are adopted to solve the equations of motion. The material properties change continuously through the core thickness of the plate, which can vary according to a power-law, exponentially, or any other formulations in this direction. This study serves as a benchmark for assessing the validity of numerical methods or two-dimensional theories used to analysis of laminated sectorial plates.