• Title/Summary/Keyword: discontinuity function

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Analysis of Microstrip Line Structures Using the Entire Domain Function along the Transverse Direction of Microstrip Lines (마이크로스트립 라인의 폭방향 전역함수를 이용한 마이크로스트립 구조의 해석)

  • Kim Jong-Sung
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.42 no.8 s.338
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    • pp.41-46
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    • 2005
  • Microstrip open-end and linear resonator are analyzed by method of moment (MoM) taking the entire-domain current distribution, found in literature, along the transverse direction of microstrip line. A transverse correlation function which incorporates permittivity, thickness and width of the line is derived. Numerical examples are investigated and compared with the available other data and methods in order to give the validity of the proposed method. It is found that the proposed method can generate more accurate results than the conventional methods.

Detection of hull side wave profile using the Mexican hat function (Mexican Hat 함수를 이용한 선측 파고 계측)

  • Kwon, S.H.;Lee, H.S.;Jung, D.J.
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2002.05a
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    • pp.270-274
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    • 2002
  • This paper presents the results of wave profile detection from video image using Mexican hat function. The Mexican hat function has been extensively used in the filed of signal processing to detect discontinuity in the images. The analysis was done on the numerical image and video images of waves which were taken in the circulating water channel. The results show that Mexican hat function is an excellent tool in the wave profile detection.

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Voltage Stability Analysis Based on Energy Function Considering Tap of Transformer (변압기 탭이 반영된 에너지 함수를 이용한 전압안정도 해석)

  • Lee Ki-Je;Choi Byoung-Kon;Kwon Yong-Jun;Moon Young-Hyun;Oh Yong-Taek;Lee Byunn-Ha
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.54 no.7
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    • pp.337-344
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    • 2005
  • An energy function is derived on the basis of the EMM(Equivalent Mechanical Model) to take account of the effects of tap changer, and then the VC(Voltage Collapse) criteria is proposed to predict the voltage collapse in Power systems. The VC criterion can be evaluated by using the energy margin given by the energy gap between UEP(Unstable Equilibrium Point) and SEP(Stable Equilibrium Point) of the energy function adopted, in which it is noted that the energy contour should be considered due to energy discontinuity associated with tap changing. This paper shows that the proposed VC criterion improves the accuracy of voltage stability analysis with application to a two-bus sample system.

Optimization technique using the eXtended FEM (X-FEM 을 이용한 최적설계 기법)

  • Huh, Jae-Sung;Akira, Tezuka;Kwak, Byung-Man
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1870-1875
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    • 2003
  • Optimization has been used in many engineering problems and must be one of the essential components during design process now. It is the process of maximizing the performance called an objective function of a system while satisfying some constraints, so finite element method is generally required in order to obtain these values during optimization. However, there are some difficulties to obtain them by means of FEM, where the changes of design variables cause the distortion and the regeneration of mesh that may result in inaccuracy and inefficiency. In order to overcome this problem, this paper proposed an alternative that the eXtended FEM introduced and developed by Ted Belytschko was applied to the optimization process because the key points of the X-FEM lie in that the discontinuity can be represented independently on the mesh by a function called in an enrichment function.

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Low-Resolution Depth Map Upsampling Method Using Depth-Discontinuity Information (깊이 불연속 정보를 이용한 저해상도 깊이 영상의 업샘플링 방법)

  • Kang, Yun-Suk;Ho, Yo-Sung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.38C no.10
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    • pp.875-880
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    • 2013
  • When we generate 3D video that provides immersive and realistic feeling to users, depth information of the scene is essential. Since the resolution of the depth map captured by a depth sensor is lower than of the color image, we need to upsample the low-resolution depth map for high-resolution 3D video generation. In this paper, we propose a depth upsampling method using depth-discontinuity information. Using the high-resolution color image and the low-resolution depth map, we detect depth-discontinuity regions. Then, we define an energy function for the depth map upsampling and optimize it using the belief propagation method. Experimental results show that the proposed method outperforms other depth upsampling methods in terms of the bad pixel rate.

Probabilistic Approach of Stability Analysis for Rock Wedge Failure (확률론적 해석방법을 이용한 쐐기파괴의 안정성 해석)

  • Park, Hyuck-Jin
    • Economic and Environmental Geology
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    • v.33 no.4
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    • pp.295-307
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    • 2000
  • Probabilistic analysis is a powerful method to quantify variability and uncertainty common in engineering geology fields. In rock slope engineering, the uncertainty and variation may be in the form of scatter in orientations and geometries of discontinuities, and also test results. However, in the deterministic analysis, the factor of safety which is used to ensure stability of rock slopes, is based on the fixed representative values for each parameter without a consideration of the scattering in data. For comparison, in the probabilistic analysis, these discontinuity parameters are considered as random variables, and therefore, the reliability and probability theories are utilized to evaluate the possibility of slope failure. Therefore, in the probabilistic analysis, the factor of safety is considered as a random variable and replaced by the probability of failure to measure the level of slope stability. In this study, the stochastic properties of discontinuity parameters are evaluated and the stability of rock slope is analyzed based on the random properties of discontinuity parameters. Then, the results between the deterministic analysis and the probabilistic analysis are compared and the differences between the two analysis methods are explained.

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HERMITE BICUBIC STREAM FUNCTION METHOD FOR INCOMPRESSIBLE FLOW COMPUTATIONS IN TWO DIMENSIONS (이차원 비압축성 유동 계산을 위한 Hermite 겹 3차 유동 함수법)

  • Kim, J.W.
    • Journal of computational fluids engineering
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    • v.13 no.4
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    • pp.13-23
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    • 2008
  • This paper is an extension of previous study[1] on a development of a divergence-free element method using a hermite interpolated stream function. Divergence-free velocity bases defined on rectangles derived herein produce pointwise divergence-free flow fields. Hence the explicit imposition of continuity constraint is not necessary and the Galerkin finite element formulation for velocities does not involve the pressure. The divergence-free element of the previous study employed hermite (serendipity) cubic for interpolation of stream function, and it has been noted a possible discontinuity in variables along element interfaces. This deficiency can be removed by use of a hermite bicubic interpolated stream function, which requires four degrees-of-freedom at each element corners. Those degrees-of-freedom are the unknown variable, its x- and y-derivatives and its cross derivative. Detailed derivations are presented for both solenoidal and irrotational basis functions from the hermite bicubic interpolated stream function. Numerical tests are performed on the lid-driven cavity flow, and results are compared with those from hermite serendipity cubics and a stabilized finite element method by Illinca et al[2].

HERMITE BICUBIC STREAM FUNCTION METHOD FOR INCOMPRESSIBLE FLOW COMPUTATIONS IN TWO DIMENSIONS (이차원 비압축성 유동 계산을 위한 Hermite 쌍 3차 유동 함수법)

  • Kim, J.W.
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03a
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    • pp.33-41
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    • 2008
  • This paper is an extension of previous study[9] on a development of a divergence-free element method using a hermite interpolated stream function. Divergence-free velocity bases defined on rectangles derived herein produce pointwise divergence-free flow fields. Hence the explicit imposition of continuity constraint is not necessary and the Galerkin finite element formulation for velocities does not involve the pressure. The divergence-free element of the previous study employed hermite serendipity cubic for interpolation of stream function, and it has been noted a possible discontinuity in variables along element interfaces. This deficiency can be removed by use of a hermite bicubic interpolated stream function, which requires at each element corners four degrees-of-freedom such as the unknown variable, its x- and y-derivatives and its cross derivative. Detailed derivations are presented for both solenoidal and irrotational bases from the hermite bicubic interpolated stream function. Numerical tests are performed on the lid-driven cavity flow, and results are compared with those from hermite serendipity cubics and a stabilized finite element method by Illinca et al[7].

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HERMITE BICUBIC STREAM FUNCTION METHOD FOR INCOMPRESSIBLE FLOW COMPUTATIONS IN TWO DIMENSIONS (이차원 비압축성 유동 계산을 위한 Hermite 쌍 3차 유동 함수법)

  • Kim, J.W.
    • 한국전산유체공학회:학술대회논문집
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    • 2008.10a
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    • pp.33-41
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    • 2008
  • This paper is an extension of previous study[9] on a development of a divergence-free element method using a hermite interpolated stream function. Divergence-free velocity bases defined on rectangles derived herein produce pointwise divergence-free flow fields. Hence the explicit imposition of continuity constraint is not necessary and the Galerkin finite element formulation for velocities does not involve the pressure. The divergence-free element of the previous study employed hermite serendipity cubic for interpolation of stream function, and it has been noted a possible discontinuity in variables along element interfaces. This deficiency can be removed by use of a hermite bicubic interpolated stream function, which requires at each element corners four degrees-of-freedom such as the unknown variable, its x- and y-derivatives and its cross derivative. Detailed derivations are presented for both solenoidal and irrotational bases from the hermite bicubic interpolated stream function. Numerical tests are performed on the lid-driven cavity flow, and results are compared with those from hermite serendipity cubics and a stabilized finite element method by Illinca et al[7].

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A study on the position control of an electro-hydraulic servomechanism using variable structure system (가변구조를 이용한 전기-유압서어보계의 위치제어에 관한 연구)

  • 허순영;권기수;하석훈;이진걸
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10a
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    • pp.299-304
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    • 1988
  • This paper describes the application of the variable structure control(VSC) concept for the position control of electro-hydraulic servomtor system. The basic philosopy of VSC is that the structure of the feedback control is altered as the state crosses discontinuity surfaces in the state surface with the result that certain desirable properties are achieved. The switching of the control function yields total(or selective) invariance to system parameter variations and disturbances, and closed loop eigen value placement in time-varing and uncertain systems.

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