• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.5
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• pp.1-7
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• 1980

In this paper, the theoretical analysis of lateral guiding in stripe geometry DH laser diode is performed. In the analysis, the carrier density profile is modeled as the function of stripe width and the beam width variations related to the stripe width are calculated using the perturbed mode theory. Finally the results of this paper are compared and analyzed with the Hakki's calculated data & kirkby's experimental data.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.10
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• pp.675-683
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• 2017

In this study, a theoretical analysis was performed to the flow of refilling stage in a safety injection tank, which is the core cooling system of nuclear power plant in an emergency. A theoretical model was proposed with a nonlinear governing equation defining on the flow of the refilling process of the coolant. Utilizing the Taylor-series expansion, the $1^{st}$ - order approximation flow equation was obtained, along with its analytic solution of closed type, which could predict accurately the variations of free surface height and flow rate of the coolant. The availability of theoretical result was confirmed by comparing with previous experimental results.

• The Journal of the Acoustical Society of Korea
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• v.32 no.4
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• pp.301-307
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• 2013

SONAR detection performance is one of the key survivability factors in underwater weapon systems. In order to catch the acoustic ability of SONAR, multilayer SONAR structures are analyzed using the elastic theory. The applied results for the simple models are compared with those from commercial program, ANSYS, and the reliable results are obtained. The analysis of sound pressure level (SPL) and echo reduction (ER) by the thickness change of multilayer SONAR structures are performed using the verified elastic theory. As the thickness of anechoic layer is increased, SPL is distributed evenly and ER is increased slightly with the frequency. In decoupling layers and steel layers, SPL are hardly changed and ER is slightly decreased with the thickness increase of those layers. SPL and ER are not affected by the thickness change of the carbon reinforced plastic (CRP) layer. Therefore, to improve the acoustic ability of multilayer SONAR structures, the thickness increase of the anechoic layer and minimization of the decoupling layer, steel layer and CRP layer are desirable.

• Computational Structural Engineering
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• v.11 no.4
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• pp.219-227
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• 1998

실제 구조물에 있어 확률, 통계 및 이론으로 구해진 랜덤성을 갖는 객관적 불확실성뿐만 아니라 설계자의 경험이나 공학적 판단에 의해 주관적으로 평가되는 인간오차나 시공중의 과오 또는 구조설계에 미치는 사회적, 정치적 및 경제적 요청 등의 퍼지성을 갖는 주관적 불확실성이 존재하기 때문에 현실적으로 랜덤성과 퍼지성을 동시에 고려한 실뢰성평가 즉, 안전성평가에 대한 퍼지이론의 도입이 필수 불가결하다. 따라서 본 연구에서는 기존 구조물의 객관적·주관적 불확실성을 동시에 고려한 신뢰성해석방법으로 베이즈의 의사결정이론에 퍼지이론을 병합한 퍼지-베이즈 신뢰성해석 알고리즘을 개발하여 건축구조물의 신뢰성평가 및 안전성평가에 적용하여 분석하였다.

• Computational Structural Engineering
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• v.8 no.3
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• pp.79-89
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• 1995

Two-element plate concept is incorporated into the buckling problem in order to simplify the nonlinear distribution of stress through the thickness of plate. Finite element formulations and programs based upon the Reissner functional and the modified Reissner functional using two-element plate concept are developed for buckling analysis of plates under axial compression. The two programs have been applied to obtain the linear elastic buckling behavior of axially compressed flat plates. Excellent agreement of linear elastic-solution results with exact or approximate solutions of other authors for the same boundary conditions proves the validity of the finite element method using two-element plate theory.

• Composites Research
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• v.17 no.2
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• pp.9-14
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• 2004

In this study, analytical investigations on the flexural behavior of FRP reinforced concrete slab were discussed. In the derivation of analytic solution, the FRP reinforced concrete slab was modeled as a structural orthotropic plate. To determine the flexural rigidities of an orthotropic plate model, the elastic equivalence method was employed. In the finite element analysis, the approximate method to determine the rigidity matrix of orthotropic plate element was also suggested using the elastic equivalence method. The results obtained by the analytical solution and the finite element analysis were compared with that of experiment.

• Computational Structural Engineering
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• v.4 no.1
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• pp.73-82
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• 1991

Recently, the finite element method has been sucessfully extended to treat the rather complex phenomena such as nonlinear buckling problems which are of considerable practical interest. In this study, a finite element program to evaluate the elasto-plastic buckling stress is developed. The Stowell's deformation theory for the plastic buckling of flat plates, which is in good agreement with experimental results, is used to evaluate bending stiffness matrix. A bifurcation analysis is performed to compute the elasto-plastic buckling stress. The subspace iteration method is employed to find the eigenvalues. The results are compared with corresponding exact solutions to the governing equations presented by Stowell and also with experimental data due to Pride. The developed program is applied to obtain elastic and elasto-plastic buckling stresses for various loading cases. The effect of different plate aspect ratio is also investigated.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.6
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• pp.691-697
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• 2007

Numerical eigen analysis of beam-like structure can be easily and effectively done by various conventional beam theory-based methods. However, in case of the structures composed of composite-sectioned beams, the application of conventional numerical methods requires one to derive both equivalent material and geometry properties. In the present paper, these equivalent properties are derived by the transformed section method and the test FEM program is coded. The numerical accuracy of the proposed method is verified through the comparison with the ANSYS 3-D model.

• Korean Journal of Logic
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• v.9 no.1
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• pp.31-62
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• 2006

이 논문은 포퍼의 후기 확률론인 성향적 확률론에 대한 것이다. 포퍼가 확률에 관한 성향이론을 제시한 가장 중요한 동기는 단일 사건에 확률값을 부여하기 위함이었다. 그의 성향이론은 전기와 후기로 나누어지는데, 전기의 이론은 성향을 반복가능한 조건들의 집합으로, 후기의 이론은 성향을 특정 시각에서의 우주의 상태로 설명한다. 이 글은 포퍼의 전기와 후기 성향이론이 성공적이지 않음을 논증한다. 전기 성향이론에 대해서는 가장 좁은 준거집합의 원리의 문제에 부딪혀서 단일 사건에 대하여 객관적인 확률값을 부여할 수 없기 때문이고, 후기 성향이론은 성향을 약한 인과라고 해석하는 문제와 함께 포퍼 자신의 의도와 달리 형이상학적인 이론이 되어버렸기 때문이다.

• Journal of the Society of Disaster Information
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• v.12 no.1
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• pp.62-68
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• 2016

In this study, the impact problems are brought up and the formulation by isoparametric element is attempted for the purpose of analyzing the response characteristics of laminated plate receiving impact load based on the first-order shear deformation theory expanded from the Mindlin plate theory. The result of static analysis and dynamic analysis is drawn through the numerical analysis rectangular and circular plates of antisymmetric Angle-Ply laminated plate using the finite element method and the analysis on each displacement is compared.