• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.159-166
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• 2001

Structural optimization often requires the evaluation of design sensitivities. The Semi Aanalytic method(SAM) for computing sensitivity is popular in shape optimization because this method has several advantages. But when relatively large rigid body motions are identified for individual elements, the SA method shows severe inaccuracy. In this paper, the improvement of design sensitivities corresponding to the rigid body mode is evaluated by exact differentiation of the rigid body modes. Moreover, the error of the SA method caused by numerical difference scheme is alleviated by using a series approximation for the sensitivity derivatives and considering the higher order terms. Finally, this paper shows that the refined SA method including the iterative method improves the results of sensitivity analysis in dynamic problems.

• Journal of Welding and Joining
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• 제16권3호
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• pp.141-147
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• 1998

Design sensitivity analysis of a vehicle system is an essential tool for design optimization and trade-off studies. Most optimization algorithms require the derivatives of cost and constraint function with respect to design in order to calculate the next improved design. This paper presents an efficient algorithm application for the design sensitivity analysis, using the direct differentiation method. A mounting area of suspension that welded on chassis frame is analyzed to show the validity and the efficiency of the proposed method. A mounting area of suspension that welded on chassis frame is analyzed to show the validity and the efficiency of the proposed method.

• 대한조선학회논문집
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• 제35권3호
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• pp.54-61
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• 1998

본 논문에서는 보유추 이론을 적용하여 초기 설계된 선체거더에 대한 상하 고유진동해석을 수행함과 동시에 설계변수 변경에 따른 고유진동수 및 고유모드의 변화율을 계산하는 감도해석방법을 활용하여 설계변경 또는 적화상태 변화시의 선체 고유진동 특성을 신속하게 예측할 수 있는 방법을 제시하였다. 이때, 이산화 해석방법은 전달행렬법을 적용하였으며, 설계변수로는 각 이산화 요소의 선체 중량, 2차원 부가수질량 및 동 3차원 수정계수, 유효굽힘강성 등으로 설정하였다. 감도해석 결과를 이용하여 중형 광석/살물운반선의 적화상태 변경시의 고유진동수를 추정한 결과는 통상적 재해석 결과와 비교하여 오차 2%이내의 매우 양호한 부합성을 나타내었다.

• 대한기계학회논문집
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• 제15권6호
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• pp.1852-1860
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• 1991

본 연구에서는 연구대상을 주어진 구조물 형상에서 경계조건의 변화에 따른 현상 설계민감도, 특히 하중경계조건의 변화에 따른 구조물의 변형에 주안점을 두었다. 이 연구결과는 가공물의 지지위치에 따른 가공면의 변형정도 향상 및 접촉문제 해석등 에 응용이 가능하다. 유도된 민감도가 정확함을 입증하기 위하여 예제로서 하중경계 조건의 변화에 따른 범함수로 정의된 변형의 변화량을 예측하는 문제를 선정하였다.

• 대한기계학회논문집A
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• 제25권1호
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• pp.153-160
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• 2001

A general procedure for the design sensitivity analysis of structural dynamic problems has been presented in frame of the FRF-based substructuring formulation. For a system response function, the proposed method gives a parametric design sensitivity formula in terms of the partial derivatives of the connection element properties and the transfer matrix of the subsystems. The derived design sensitivity formula is applied to an engine mount system. An interior noise problem in the passenger car is analyzed using the FRF-based substructuring method and the proposed formulation is adopted to study the response variations with respect to the dynamic characteristics of the engine mounts and the bushes. To obtain the FRFs, a finite element model is built for the engine mount structures, and test data is used for the trimmed body including cabin cavity. The comparison of sensitivities derived by the proposed method and the finite difference method shows that the proposed method is efficient and accurate. The proposed sensitivity analysis method indicates effectively the most sensitive location to the interior noise among the engine mounts and the bushes.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.796-801
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• 2002

The goal of this research is the shape design of the valve using a computer simulation. For an analysis a basic mathematical model describing compression cycle is considered as consisting of five sets of coupled equations. These are the volume equation (kinematics), valve dynamic equation (dynamics), ideal gas equation (thermodynamics), Bernoulli equation (fluid dynamics), and dynamic equation of fluid particle based on Helmholtz equation (acoustics). Valve motion is made by the superposition of free vibration modes obtained by the finite element method. That is, the eigenvalues and eigenvectors are the sufficient modeling factors fur the valve in the simulation program. Thus, to design a shape of the valve, shape design sensitivity through chain-ruled derivatives is considered from two sensitivity coefficients, one is the design sensitivity of the capability of compressor with respect to the eigenvalues of the valve, and the other is the design sensitivity of the eigenvalue with respect to the shape change of the valve. In this research, the continuum design sensitivity analysis concepts are used for the latter.

• 공업화학
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• 제10권8호
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• pp.1169-1174
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• 1999

본 연구에서는 sodium 2-diazo-1-naphthoquinone-5-sulfonate를 chlorination하여 2-diazo-naphthoquinone-5-sulfonyl chloride(NQD-Cl)를 합성하였다. NQD-Cl을 여러 종류의 hydroxybenzophenone 유도체와 esterification하여 hydroxy group이 2-diazo-naphthoquinone-5-sulfonyl(NQD) group으로 치환된 여러 종류의 1,2-naphthoquinone-(1,2)-diazide-5-sulfonic acid esters(NQD0ester) 유도체를 합성하였다. NQD-ester 유도체의 용해도를 증가시키기 위해 methoxy group이 도입된 유도체와 이와 비교를 위해 hydroxy group만을 가지는 benzophenone 유도체를 사용하여 비교하였다. 각각의 NQD-ester 유도체의 용해특성을 조사하였으며, novolac수지와 혼용(formulation)하여 감광액을 제조하여 알루미늄판에 도포, 건조하여 PS판을 제조하였다. PS판의 감광특성과 광퇴색도와 화상형성에 적합한 노광시간을 조사하였으며, 상대감도를 gray scale(GS)법으로 조사하였다. 치환된 NQD group 의 수에 따라 GS법에 의한 상대감도가 다르게 나타나는 것을 알 수 있었다. Methoxy group이 도입된 NQD-ester유도체는 좋은 용해특성을 보여주었으며 시판되는 PS판과 동일한 노광조건에서 비교해 본 결과 보다 우수한 감도를 보였다.

• International Journal of Aeronautical and Space Sciences
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• 제17권2호
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• pp.268-283
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• 2016

Aircraft manufacturing companies have to consider multiple derivatives to satisfy various market requirements. They modify or extend an existing aircraft to meet new market demands while keeping the development time and cost to a minimum. Many researchers have studied the derivative design process, but these research efforts consider baseline and derivative designs together, while using the whole set of design variables. Therefore, an efficient process that can reduce cost and time for aircraft derivative design is needed. In this research, a more efficient design process is proposed which obtains global changes from local changes in aircraft design in order to develop aircraft derivatives efficiently. Sensitivity analysis was introduced to remove unnecessary design variables that have a low impact on the objective function. This prevented wasting computational effort and time on low priority variables for design requirements and objectives. Additionally, uncertainty from the fidelity of analysis tools was considered in design optimization to increase the probability of optimization results. The Reliability Based Design Optimization (RBDO) and Possibility Based Design Optimization (PBDO) methods were proposed to handle the uncertainty in aircraft conceptual design optimization. In this paper, Collaborative Optimization (CO) based framework with RBDO and PBDO was implemented to consider uncertainty. The proposed method was applied for civil jet aircraft derivative design that increases cruise range and the number of passengers. The proposed process provided deterministic design optimization, RBDO, and PBDO results for given requirements.

• BMB Reports
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• 제28권6호
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• pp.471-476
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• 1995

Acetolactate synthase (ALS) catalyzes the first common step in the biosynthesis of valine, leucine, and isoleucine. ALS is the target enzyme for several classes of structually diverse herbicides. We have synthesized 4,6-dimethoxypyrimidine derivatives as ALS inhibitors, and their inhibitory activities on barley ALS were determined. $IC_{50}$ values for the derivatives are 0.2~200 ${\mu}m$. K11570, the most potent ALS inhibitor with $IC_{50}$ of 0.2 ${\mu}m$, showed mixed-type inhibition with respect to substrate pyruvate, and the progress curves for ALS inhibition by K11570 indicated that the amount of inhibition increased with time. Inhibition-competition experiments were carried out and indicated that three different classes of inhibitors, K11570, a sulfonylurea Ally, and leucine, bind to ALS in a mutually exclusive manner. Chemical modification of tryptophanyl and tyrosyl residues of ALS decreased the sensitivity of ALS to K11570, while cysteine modification did not affect the sensitivity. These results suggest that tryptophanyl and tyrosynyl residues are probably located at or near the inhibitor binding site.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.154-156
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• 1996

A new method for electric resistivity tomography(ERT) is developed for geophysical inverse problems by adapting the sensitivity analysis. The outputs of the potential electrodes are computed using two dimensional finite element method in the wave number space by Fourier transforming the governing equations. The resistance distribution in the region of interests, which makes the computed potential distribution coincide with the measured potential, is found by minimizing the objective function using an optimization method. In this process the sensitivity analysis is introduced in order to compute the derivatives of the objective function. And an adjoint variable method is used to save the computational efforts for sensitivity coefficients.