• Title/Summary/Keyword: discontinuity region

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Suppression of Discontinuity in the Pseudoscopic Region of Multiview 3D Displays

  • Lee, Jae-Yong;Miyashita, Tetsuya;Uchida, Tatsuo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.1107-1111
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    • 2009
  • Flat panel multiview 3D displays developed in recent years have pseudoscopic regions that appear unnatural to viewers. We suggest a new method to suppress the pseudoscopic regions based on the visual characteristics of binocular rivalry. We confirm the validity of this method experimentally and show that the unnaturalness caused by pseudoscopic regions can be effectively suppressed.

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An Improved Mesh-free Crack Analysis Technique Using a Singular Basis Function (특이기저함수를 이용하여 개선한 Mesh-free 균열해석기법)

  • 이상호;윤영철
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.14 no.3
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    • pp.381-390
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    • 2001
  • In this paper, a new improved crack analysis technique by Element-Free Galerkin(EFG) method is proposed, in which the singularity and the discontinuity of the crack successfully described by adding enrichment terms containing a singular basis function to the standard EFG approximation and a discontinuity function implemented in constructing the shape function across the crack surface. The standard EFG method requires considerable addition of nodes or modification of the model. In addition, the proposed method significantly decreases the size of system of equation compared to the previous enriched EFG method by using localized enrichment region near the crack tip. Numerical example show the improvement and th effectiveness of the previous method.

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Static Analysis of Gas Bearing with Ultra Low Clearance by the Direct Numerical Solution Method (극소 공기막을 갖는 공기베어링의 직접수치해법을 이용한 정적해석)

  • Park, Sang-Sin;Chang, In-Bae;Hwang, Pyung;Han, Dong-Chul
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.1
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    • pp.120-126
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    • 1991
  • An expanded scheme of a direct numerical solution method for solving the Navier-Stokes equation considering the modified boundary conditions for gas lubrication with ultra low clearance at high .LAMBDA. region is presented. Many examples are calculated by this scheme and their results are compared to the previous solutions using P$^{2}$H$^{[-992]}$ . This scheme has the advantages of fast calculation time and stable convergence in high .LAMBDA. region, and gives very good results in the case of fluid film thickness discontinuity.

Papers : Analysis of Numerical Instability of AUSM - type Schemes (논문 : AUSM 계열 수치기법의 수치적 불안정성에 대한 분석)

  • Kim,Gyu-Hong;Lee,Gyeong-Tae;Kim,Jong-Am;No,O-Hyeon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.3
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    • pp.27-36
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    • 2002
  • Numerical stability is studied based on numerics and mathematics. It is frequently observed in the region where velocity is zero. In that region, the Euler equation have numerous solutions and, thus, it is impossible to determine a unique solution with only governing equations. However, a unique solution can be determined by additional outer flow conditions or outer numerical discontinuity calculation since the information or a unique solution under undisturbed conditions is lost by disturbances. In this reason, the numerical scheme comsistent with Euler equations cannot remove shock instability completely.

An Automatic Discontinuity Extraction Method from 3D Seismic Data (3차원 탄성파 자료로부터 불연속면 자동 추출기법)

  • Ji Jun
    • Geophysics and Geophysical Exploration
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    • v.4 no.3
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    • pp.89-95
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    • 2001
  • The final goal of the seismic method is to verify the spatial characteristic of subsurface media. For this purpose, professional interpreters interprete the discontinuities of seismic events from seismic image. This paper introduces a method for automatic discontinuity extraction from 3D seismic image. The method consists of three steps. The first step is for estimating coherency of seismic events from seismic data. The second step is to express the potential region where discontinuities may exist in the form of binary image. The third step is to locate the discontinuities by thining the region found in the second step.

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An Integral Equation for Kinked Cracks in Finite Plane Bodies (유한영역에서의 꺾인균열 해석을 위한 적분방정식 적용 연구)

  • 서욱환
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.9
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    • pp.2138-2144
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    • 1993
  • An integral equation representation of cracks was presented which differs from well-known "dislocation layer" representation. In this new representation, the equations are written in terms of the displacement discontinuity across the crack surfaces rather than derivatives of the displacement-discontinuity. It was shown in that the new technique is well-suited to the treatment of kinked cracks. In the present paper, this integral equation representation is coupled to the direct boundary-element method for the treatment of finite bodies containing kinked cracks. The method is demonstrated for two-dimensional finite domains but extension to three-dimensional problems would appear to be possible. The resulting approach is shown to be simple, yet very accurate. accurate.

Moving Mesh Application for Thermal-Hydraulic Analysis in Cable-In-Conduit-Conductors of KSTAR Superconducting Magnet

  • Yoon, Cheon-Seog;Qiuliang Wang;Kim, Keeman;Jinliang He
    • Journal of Mechanical Science and Technology
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    • v.16 no.4
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    • pp.522-531
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    • 2002
  • In order to study the thermal-hydraulic behavior of the cable-in-conduit-conductor (CICC), a numerical model has been developed. In the model, the high heat transfer approximation between superconducting strands and supercritical helium is adopted. The strong coupling of heat transfer at the front of normal zone generates a contact discontinuity in temperature and density. In order to obtain the converged numerical solutions, a moving mesh method is used to capture the contact discontinuity in the short front region of the normal zone. The coupled equation is solved using the finite element method with the artificial viscosity term. Details of the numerical implementation are discussed and the validation of the code is performed for comparison of the results with thse of GANDALF and QSAIT.

Characteristic Analysis of Shear Strength of Rock Slope Discontinuity in Yangsan Fault System (양산단층대 암반비탈면에 분포하는 불연속면의 전단강도 특성분석)

  • Lee, Hak-Ju;Kim, Chang-Ho;Hwang, Woong-Ki;Kim, Tae-Hyung
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.3
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    • pp.11-22
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    • 2019
  • This study was conducted to identify the causes of the unusually high number of rock slope failures during an expressway construction in Yangsan fault system. The shear strength (cohesion and internal friction angle) of 128 slopes of discontinuities including bedding, joint, and fault planes were re-evaluated through the examination of face mapping and back analysis. The re-evaluated values were analyzed and then compared with the existing data and values used in the design. As a result, the re-evaluated cohesion and friction angles were very low compared to the existing data and the values applied in the design. This incongruity was pointed as the primary reason for the rock slopes failures during the construction. This may be related to the inherent features of clastic sedimentary rocks in the study area, and the discontinuities in the sedimentary rocks in this region played a significant role. Especially, bedding discontinuity showed a big difference compared to the existing data. The shear strength depended on the type of discontinuity in case of clay filled in discontinuity. However, shear strength was independent on the type of discontinuity in case of shattered materials filled in discontinuity.

Application of Geophysical Exploration Technique to the Identification of Active Weak Zones in Large Scale Mountainous Region (대규모 산지지반 활동연약대 규명을 위한 지구물리탐사기법의 활용 연구)

  • Shin, Hyung Ohk;Kim, Man-Il;Yoon, Wang Joong
    • Geophysics and Geophysical Exploration
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    • v.21 no.3
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    • pp.162-170
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    • 2018
  • The purpose of this study is to understand the ground change of large scale mountainous region and to estimate the active weak zone using geophysical exploration (electrical resistivity and refraction seismic explorations) in large scale deep landslide area located in Wanjugun, Jeollabukdo. We also analyzed the characteristics of deep landslides occurred in metamorphic rocks region and confirmed the approximate scale. As a result of comparative analysis of N-value by standard penetration test (SPT), low resistivity anomaly, and tension crack identified from field investigation, a discontinuity in soil layer was estimated at 10 ~ 15 m below the surface. Based on this results, the distribution pattern of active weak zone was confirmed between the discontinuity in soil layer and estimation line of bedrock.