• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1586-1595
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• 2018

For the problem that the complexity of 3-D modeling and multi parameter optimization, as well as the uncertainty of the winding factor of axial flux permanent magnet generator with coreless windings. The complex 3-D model was simplified into 2-D analytic model, and an analytical formula for the winding factor that adapting different coreless stator winding is proposed in this paper. The analytical solution for air-gap magnetic fields, no-load back EMF, electromagnetic torque, and efficiency are calculated by using this method. The multiple objective and multivariable optimization of the maximum fundamental and the minimum harmonic content of back EMF are performed by using response surface methodology. The proposed optimum design method was applied to make a generator. The generator was tested and the calculated results are compared with the proposed method, which show good agreements.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권3호
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• pp.289-294
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• 2012

In this paper, the three-dimensional magnetic field created by non-periodic magnet arrays is calculated analytically. The analytical expression of the magnetic field is derived by using a magnetic charge model. The influence of ferromagnetic boundaries is formulated with an image method. Finally, we compare the results determined by analytical calculations to those from a finite element simulation.

• 한국작물학회지
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• 제12권
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• pp.1-5
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• 1972

수도 고단백 계통선발을 위한 미립내 질소함량 검정 방법을 첨부 검토하기 위하여 예비선발된 36계통 및 대조품종을 5가지 질소수준(0, 7.5, 15.0, 22.5, 30.0, kg/10a)에서 재배하여 그 현미를 Kjeldahl법, Dye binding법 및 Biurett법으로 분석하여 3가지 방법에 의한 분석치간의 상관을 검토하였으며 그 중 6개품종에 대하여 동일시료를 3가지 분석법으로 6회 반복한 분석치의 분산을 검토하였고 3가지 방법으로 시료 100점당 소요된 시약과 노력을 비교하였다. 그 결과를 요약하면 다음과 같다. 1. D.B.C.법에 의한 분석치는 Biurett법에 의한 분석치보다 Kjeldahl법과의 상관이 높았으나 D.B.C. 법에서는 극도로 높은 질소수준에서와 극도로 낮은 질소수준에서의 분석치는 Kjeldahl법에 의한 분석치에 비하여 과대평가되는 경향이 있다. Biurett법은 비교적 오차가 커서 Kjeldahl 법과의 상관이 떨어지지만 모든 질소수준에서 평행적인 경향이었다. 2. 품종에 따라 시용된 질소수주에 대한 반응도 달랐지만 품종과 질소수준에 따라 3가지 분석방법의 반응도 달랐다. 3. 3가지 분석방법별 분석치의 변이계수를 비교하면 Biurett법이 가장 크며 다음은 D.B.C.법인데 Biurett법에서는 각질소수준에서 모두 높았지만 질소수준이 높아짐에 따라 변이계수도 커졌는데 Kjeldahl법이나 D.B.C.에서는 질소수준이 낮아짐에 따라 변이 계수가 커졌다. 4. 3가 분석방법에서 소요되는 약품과 노력을 조사하여 Kjeldahl법에 비하여 D.B.C.법이 현저하게 절약되며 D.B.C.법 보다 Biurett법은 더욱 절약될 수 있음을 알았다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제5권2호
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• pp.71-99
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• 2001

The model and analytical method for solving the problem of coupled fluid flow in the reservoir/well system is presented. The 3-D drainage area is composed of three connected media: the tubing, the annuli as a super conducting collector, and the reservoir itself. To couple these three types of fluid flows a non-overlapping Dirichlet-Neumann domain decomposition method is developed. The method allows us to apply an analytical hybrid simulator for accurate evaluation of the impact of main geometrical and hydrodynamic parameters of the 3-D system on the pressure drop along the horizontal well and its production index.

• 한국전기전자재료학회논문지
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• 제25권1호
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• pp.6-14
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• 2012

For integrated complementary metal oxide semiconductor (CMOS) circuits, the lateral spread for two-dimensional (2-D) impurity distributions are very important for the analyzing the devices. The measured two-dimensional SEM data obtained using the chemical etching-method matched very well with the results of the Gauss model for boron implanted samples. But the profiles in boron implanted silicon were deviated from the Gauss model. The profiles in boron implanted silicon were shown a little bit steep profile in the deep region due to backscattering effect on the near surface from the bombardments of light boron ions. From the simulated 3-D data obtained using an analytical model, the 1-D and 2-D data were compared with the experimental data and could be verified the justification from the experimental data. The data of 3-D model were also shown good agreements with the experimental and the simulated data. It can be used in the 3-D chip design and the analysis of microelectro-mecanical system (MEMS) and special devices.

• Structural Engineering and Mechanics
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• 제32권3호
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• pp.447-457
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• 2009

A general analytical method for computing the joint stiffness from the sectional properties of the members that form the joint is derived using Vlasov's thin-walled beam theory. The analytical model of box T-joint under out-of-plane loading is investigated and validated using shell finite element results and experimental data. The analytical model of the T-joint is implemented in a beam finite element model using a revolute joint element. The out-of-plane displacement computed using the beam-joint model is compared with the corresponding shell element model. The results show close correlation between the beam revolute joint model and shell element model.

• Steel and Composite Structures
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• 제39권3호
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• pp.291-306
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• 2021

Based on Reissner's mixed variational theorem (RMVT), the authors develop a semi-analytical finite element (FE) method for a three-dimensional (3D) bending analysis of nonhomogeneous orthotropic, complete and incomplete toroidal shells subjected to uniformly-distributed loads. In this formulation, the toroidal shell is divided into several finite annular prisms (FAPs) with quadrilateral cross-sections, where trigonometric functions and serendipity polynomials are used to interpolate the circumferential direction and meridian-radial surface variations in the primary field variables of each individual prism, respectively. The material properties of the toroidal shell are considered to be nonhomogeneous orthotropic over the meridianradial surface, such that homogeneous isotropic toroidal shells, laminated cross-ply toroidal shells, and single- and bi-directional functionally graded toroidal shells can be included as special cases in this work. Implementation of the current FAP methods shows that their solutions converge rapidly, and the convergent FAP solutions closely agree with the 3D elasticity solutions available in the literature.

• Design & Manufacturing
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• 제13권2호
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• pp.6-11
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• 2019

In this study, we constructed the mathematical model to evaluate the roundness for plastic injection mold parts with complicated 3D curvatures. Mathematically we started off from the equation of circle and successfully derived an analytical solution so as to minimize the area of the residuals. On the other hand, we employed the numerical method the similar optimization process for the comparison. To verify the mathematical models, we manufactured and used a ball valve type plastic parts to apply the derived model. The plastic parts was fabricated under the process conditions of 220-ton injection mold machine with a raw material of polyester. we experimentally measured (x, y) position using 3D contact automated system and applied two mathematical methods to evaluated the accuracy of the mathematical models. We found that the analytical solution gives better accuracy of 0.4036 compared to 0.4872 of the numerical solution. The numerical method however may give adaptiveness and versatility for optional simulations such as a fixed center.

• Structural Engineering and Mechanics
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• 제78권4호
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• pp.485-496
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• 2021

So far analytical methods on collapse assessment of three-dimensional (3-D) steel frames have mainly focused on a single-column-removal scenario. However, the collapse of the Federal Building in the US due to car bomb explosion indicated that the loss of multiple columns may occur in the real structures, wherein the structures are more vulnerable to collapse. Meanwhile, the General Services Administration (GSA) in the US suggested that the removal of side columns of the structure has a great possibility to cause collapse. Therefore, this paper analytically deals with the robustness of 3-D steel frames in a two-side-column-removal (TSCR) scenario. Analytical method is first proposed to determine the collapse resistance of the frame during this column-removal procedure. The reliability of the analytical method is verified by the finite element results. Moreover, a design-based methodology is proposed to quickly assess the robustness of the frame due to a TSCR scenario. It is found the analytical method can reasonably predict the resistance-displacement relationship of the frame in the TSCR scenario, with an error generally less than 10%. The parametric numerical analyses suggest that the slab thickness mainly affects the plastic bearing capacity of the frame. The rebar diameter mainly affects the capacity of the frame at large displacement. However, the steel beam section height affects both the plastic and ultimate bearing capacity of the frame. A case study on a six-storey steel frame shows that the design-based methodology provides a conservative prediction on the robustness of the frame.

• 한국산학기술학회논문지
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• 제17권9호
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• pp.724-731
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• 2016

지진으로 인한 구조물의 피해가 지속적으로 증가하면서, 구조물의 취약성을 평가하는 일은 지진 대비에 필수적으로 여겨지고 있다. 지진 취약도 곡선은 지진에 대한 구조물의 안전도에 대한 확률 지표로써 널리 이용되고 있으며, 많은 연구자들에 의해 보다 정확하고 효율적인 취약도 곡선 도출을 위한 노력이 계속되고 있다. 하지만 기존의 대부분의 연구에서는 취약도 곡선 도출시 수치해석 시간 절약을 위해 단순화된 2차원 해석모델을 사용해 왔는데, 많은 경우에 있어 2차원 모델은 정확한 구조물의 내진 거동 및 지진 취약성을 평가하기에 적당하지 않을 수 있다. 이에 본 연구에서는 3차원 해석 모델을 사용하여 더욱 정확하면서도 여전히 효과적으로 지진 취약도 곡선을 도출할 수 있는 방법을 제시한다. 이 방법은 신뢰성 해석 소프트웨어인 FERUM과 구조해석 소프트웨어인 ZEUS-NL을 서로 연동시켜 상호 자동적인 데이터 교환이 가능하게 하고, 샘플링 기법이 아닌 FORM 해석 기법을 통해 구조물의 파괴확률을 구한다. 이는 3차원 모델을 사용의 경우에도 효율적으로 구조 신뢰성 해석이 가능하게 해준다. 이를 이용해 RC 프레임 구조물의 3차원 해석 모델을 사용하여 지진 취약성 평가를 수행하였다.