• 전기학회논문지
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• 제65권5호
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• pp.745-752
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• 2016

The parameters of Debye's equation were applied to analyze the frequency-dependent ground impedance of horizontally-buried wires. We present a new method, based on Debye's equation, of analyzing the effect of polarization on frequency-dependent ground impedance. The frequency-dependent ground impedances of a horizontally-buried wire are directly measured and calculated by applying sinusoidal current in the frequency range of 100 Hz to 10 MHz. Also, the results obtained in this work were compared with the data calculated from empirical equations and commercial programs. A new methodology using the delta-gap source model is proposed in order to calculate frequency-dependent ground impedance when the ground current is injected at the middle-point of the horizontal ground electrode. The high frequency ground impedance of horizontal electrodes longer than 30 m is larger or equal to its low frequency ground resistance. Consequently, the frequency-dependent ground impedance simulated with the proposed method is in agreement with the experimental data, and the validity of the computational simulation approach is confirmed.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1999년도 춘계 학술대회논문집
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• pp.192-198
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• 1999

The present study proposes modified temperature-dependent non-Newtonian viscosity model and investigates flow characters and heat transfer enhancement of the viscoelastic non-Newtonian fluid in a 2:1 rectangular duct. The proposed modified temperature dependent viscosity model has non-zero value near the high temperature and high shear rate region while on the existing viscosity models have zero value. Two versions of thermal boundary conditions involving difference combination of heated walls and adiabatic walls are analyzed in this study. The combined effect of temperature dependent viscosity, buoyancy, and secondary flow caused by second normal stress difference are ail considered. The Reiner-Rivlin model is adopted as a viscoelastic fluid model to simulate the secondary flow caused by second normal stress difference. Calculated Nusselt numbers by the modified temperature-dependent viscosity model gives under prediction than the existing temperature-dependent viscosity model in the regions of thermally developed with same secondary normal stress difference coefficients with experimental results in the regions of thermally developed. The heat transfer enhancement of the viscoelastic fluid in a 2:1 rectangular duct is highly dependent on the secondary flow caused by the magnitude of second normal stress difference.

• Geomechanics and Engineering
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• 제29권1호
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• pp.41-51
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• 2022

Tunneling in rocks having the time-dependent behavior, causes some difficulties like tunnel convergence and, as a result, pressure on concrete lining; and so instability on this structure. In this paper the time-dependent behaviour of squeezing phenomenon in a large cross section tunnel was investigated as a case study: Alborz tunnel. Then, time-dependent behaviour of Alborz tunnel was evaluated using FLAC2D based on the finite difference numerical method. A Burger-creep viscoelastic model was used in numerical analysis. Using numerical analysis, the long-time effect of squeezing on lining stability was simulated.This study is done for primary lining (for 2 years) and permanent lining (for 100 years), under squeezing situations. The response of lining is discussed base on Thrust Force-Bending Moment and Thrust Force-Shear Force diagrams analysing. The results determined the importance of consideration of time-dependent behaviour of tunnel that structural forces in concrete lining will grow in consider with time pass and after 70 years can cause instability in creepy rock masses section of tunnel. To show the importance of time-dependent behavior consideration of rocks, elastic and Mohr-Coulomb models are evaluated at the end.

• ETRI Journal
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• 제44권1호
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• pp.51-61
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• 2022

In this paper, we introduced a novel voxel-wise UV parameterization and view-dependent texture synthesis for the immersive rendering of a truncated signed distance field (TSDF) scene model. The proposed UV parameterization delegates a precomputed UV map to each voxel using the UV map lookup table and consequently, enabling efficient and high-quality texture mapping without a complex process. By leveraging the convenient UV parameterization, our view-dependent texture synthesis method extracts a set of local texture maps for each voxel from the multiview color images and separates them into a single view-independent diffuse map and a set of weight coefficients for an orthogonal specular map basis. Furthermore, the view-dependent specular maps for an arbitrary view are estimated by combining the specular weights of each source view using the location of the arbitrary and source viewpoints to generate the view-dependent textures for arbitrary views. The experimental results demonstrate that the proposed method effectively synthesizes texture for an arbitrary view, thereby enabling the visualization of view-dependent effects, such as specularity and mirror reflection.

• 한국동물학회지
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• 제23권2호
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• pp.61-68
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• 1980

발정주기에 EK라서 생쥐자궁의 alkaline phosphatase와 transport ATPases의 활성변화를 알아보기 위하여 정량적으로 분석하였다. 발정주기의 각 시기에 있어서 이 효소활성들의 비율은 대체로 그 양상이 서로 비슷하나, 발정기의 $K^+$-dependent와 $Na^+, K^+$-activated ATPases를 제외한 다른 효소들의 활성은 다른 어떤 시기보다도 유의하게 (p<0.025) 높았다. 즉, $K^+$-dependent와 $Na^+, K^+$-activated ATPases의 활성은 발정간기에서 발정기에 이르는 동안 무시할 정도이고, 다만 발정후기에 약간의 활성(0.04$\\sim$0.05 $\\mu$M/mg protein/hr), 총활성의 6$\\sim$7%)이 나타났다. 한편, 발정기에서 $Mg^++$-dependent phosphatase, transport ATPase와 alkaline phosphatase의 활성들은 급속히 현저하게 증가하였으며 각각 0.69(35%), 0.42(21%), 1.58(79%)였다. Alkaline phosphatase는 전 발정주기를 통해 0.60$\\sim$1.58(79$\\sim$90%)의 활성을 보여 그 주종을 이루었다. Alkaline phosphatase의 활성중에는 $Mg^++$-dependent의 것이 총활성의 12$\\sim$16%로 추정되었다. 그러므로 $K^+$-dependent와 $Na^+$-activated ATPases는 발정기 때에 자궁액의 누적을 조절하는 요인이 아니고 발정후기에는 자궁상피 속으로 내액을 재흡수하는 요인인 것으로 짐작되며, EH한 $Mg^++$-dependent phosphatase, transport ATPase 그리고 alkaline phosphatase는 생쥐의 자궁 상피세포에서부터 내액을 분지하는 데에 밀접히 관련되어 있는 것으로 사려된다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제31회 춘계학술대회
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• pp.3-10
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• 2000

The undesired situation of development of tribology and its reason is analyzed. The problem comes from insufficient study on the concept system and method system, which can match the name, definition and nature of tribology. The existence of three axioms in tribology is discussed. They are axiom of system dependent, axiom of time dependent and axiom of coupling of behaviors of multi-discipline. A series of lemmas has been deduced from three axioms. It is expected that they can be a foundation to establish the concept system and method system.

• 한국해양공학회지
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• 제6권2호
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• pp.125-132
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• 1992

This paper presents an approach for the derivation of frequency-dependent element matrices for vibration analysis of piping systems containing a moving medium. The dynamic stiffness matrix is deduced from transfer matrix, and, in turn, the frequency-dependent element matrices are derived. Numerical examples show that method gives more accurate results than those obtained using the conventional static shape function based element matrices.

• 대한수학회지
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• 제50권2호
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• pp.379-392
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• 2013

A general result for the complete convergence of arrays of rowwise extended negatively dependent random variables is derived. As its applications eight corollaries for complete convergence of weighted sums for arrays of rowwise extended negatively dependent random variables are given, which extend the corresponding known results for independent case.

• Journal of applied mathematics & informatics
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• 제30권1_2호
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• pp.57-69
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• 2012

In this paper, we prove the existence of mild solutions for a first order impulsive neutral differential inclusion with state dependent delay. We assume that the state-dependent delay part generates an analytic resolvent operator and transforms it into an integral equation. By using a fixed point theorem for condensing multi-valued maps, a main existence theorem is established.

• Journal of applied mathematics & informatics
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• 제29권1_2호
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• pp.201-210
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• 2011

In this paper, we obtain the H$\`{a}$jeck-R$\`{e}$nyi type inequality and the strong law of large numbers for asymptotically linear negative quadrant dependent random variables by using this inequality. We also give the strong law of large numbers for the linear process under asymptotically linear negative quadrant dependence assumption.