• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.7
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• pp.601-608
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• 2015

The static aeroelastic analysis and optimization of flexible wings are conducted for steady state conditions while both aerodynamic and structural parameters can be used as optimization variables. The system of multidisciplinary design optimization as a robust methodology to couple commercial codes for a static aeroelastic optimization purpose to yield a convenient adaptation to engineering applications is developed. Aspect ratio, taper ratio, sweepback angle are chosen as optimization variables and the skin thickness of the wing. The real-coded adaptive range multi-objective genetic algorithm code, which represents the global multi-objective optimization algorithm, was used to control the optimization process. The support vector regression(SVR) is applied for optimization, in order to reduce the time of computation. For this multi-objective design optimization problem, numerical results show that several useful Pareto optimal designs exist for the flexible wing.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.116-120
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• 2007

도시 지역 소규모 단지 개발 후 유출량 증가로 인한 하류지역의 첨두유량의 조절은 도시 호우 관리에서 가장 중요한 고려 대상중의 하나이다. 최적관리를 위한 단지 내 유수지는 오리피스와 위어를 이용하여 높은 첨두율을 개발전의 첨두유량으로 조절하는 역할을 담당 한다. 이 연구에서는 도시 개발에 따른 단지 내 다목적 저류지를 설치하여 첨두유량을 조절하기 위하여 오리피스와 위어가 설치된 저류지를 어떻게 설계하는지 검토하였다. 적용 대상은 전형적인 도시소유역 단지개발지역에 적용하였다. 저류지는 재현기간 2년 10년 그리고 100년 설계 강우에 대한 첨두유량을 조절할 수 있도록 설계되었다. 또한 도시화의 진행으로 인한 불투수면적의 증가에 따른 예민도 분석을 실시하여 유출량의 증가와 하류단에서 나타나는 첨두유량의 변화를 검토하였다. 설계 저류지 모의를 위하여 SWMM 5.0을 사용하였다.

• Journal of the Korea Society for Simulation
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• v.16 no.2
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• pp.45-54
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• 2007

In this article, we propose a different modeling approach, which aims at the simulation optimization so as to meet the design specification. Generally, Multi objective optimization problem is formulated by dependent factors as objective functions and independent factors as constraints. However, this paper presents the critical(dependent) factors as objective function and design(independent) factors as constraints for the selection of design factors directly. The objective function is normalized far the generalization of design factors while the constraints are composed of the simulation-based regression metamodels fer the critical factors and design factor's domain. Then the effective and fast solution procedure based on the pareto optimal solution set is proposed. This paper provides a comprehensive framework for the system design using the simulation and metamodels. Therefore, the method developed for this research can be adopted for other enhancements in different but comparable situations.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.94-101
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• 2003

Recently, miniaturization and weight reduction is getting more attention due to various benefits in automotive components design. It is a trend that the design of experiment(DOE) and statical design method are frequently used for optimization. In this research, the safety of lower control arm is evaluated according to its material change form S45C to A16061 for the reduction of arm's weight. The variance analysis on the basis of structure analysis and DOE is applied to the lower control m. We have proposed a statistical design model to evaluate the effect of structural modification by performing the practical multi-objective optimization considering mass, stress and deflection.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.127-134
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• 2004

It is difficult to have the existing structural optimization using coupled field analysis from CFD to structure analysis when the structure is influenced of fluid. Therefore in an initial model of this study after doing parameter design from the background of shape using topology optimization. and it is making a approximation formula using by the CFD-structure coupled-field analysis and design of experiment. By using this result, we conducted multi-objective optimization. We could confirm efficiency of stochastic method applicable in the scene of structure reliability design to be needed multi-objective optimization. And we presented a way of design that could overcome the time and space restriction in structural design such as the butterfly valve with the less experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.365.1-365
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• 2002

저소음 팬의 설계는 팬 성능의 저감 없이 이루어져야 한다. 마라서 저소음 팬 설계는 기본적으로 다분야간 설계 최적화 또는 다목적 설계 최적화의 문제이다. 본 연구에서는 이러한 요구를 수행하기 위해 반응면 기법을 저소음 축류 팬 설계에 적용하여 보았다. 또한 이러한 설계 단계에서 필요한 수백가지 시험 결과를 효과적으로 구하기 위해 효율적인 유동 해석 툴과 소음 해석 툴을 개발하여 적용시켰다. (중략)

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.170-175
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• 2001

The design cycle associated with large engineering systems requires an initial decomposition of the complex system into design processes which are coupled through the transference of output data. Some of these design processes may be grouped into iterative subcycles. In analyzing or optimizing such a coupled system, it is essential to determine the best order of the processes within these subcycles to reduce design cycle time and cost. This is accomplished by decomposing large multidisciplinary problems into several multidisciplinary analysis subsystems (MDASS) and processing it in parallel. This paper proposes new strategy for parallel decomposition of multidisciplinary problems to improve design efficiency by using the multiple objective genetic algorithm (MOGA), and a sample test case is presented to show the effects of optimizing the sequence with MOGA.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.4
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• pp.499-506
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• 2003

The design cycle associated with large engineering systems requires an initial decomposition of the complex system into design processes which are coupled through the transference of output data. Some of these design processes may be grouped into iterative subcycles. In analyzing or optimizing such a coupled system, it is essential to determine the best order of the processes within these subcycles to reduce design cycle time and cost. This is accomplished by decomposing large multidisciplinary problems into several sub design structure matrices (DSMs) and processing them in parallel This paper proposes a new method for parallel decomposition of multidisciplinary problems to improve design efficiency by using the multi-objective genetic algorithm and two sample test cases are presented to show the effect of the suggested decomposition method.

• Proceedings of the Korea Society for Simulation Conference
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• 2002.11a
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• pp.3-7
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• 2002

컴퓨터 네트워킹 기술의 발달에 힘입어 분산처리를 이용한 기법이 복잡한 구조물의 최적설계에 널리 사용되고 있다. 최적설계시 구조물이 복잡하고 설계 변수가 많아질수록 설계 변수간의 교호작용이 복잡해지고 국부최적해가 많아지는 특성이 있다. 최근의 최적 설계는 이러한 문제점을 해결하고자 다양한 전역 최적화 기법을 도입하여 적용하고 있다. 본 연구에서는 진화이론을 바탕으로 한 유전자 알고리즘과 실험계획법을 바탕으로 한 반응표면법에 분산처리 기법을 도입하여 인공위성 추진 모듈의 최적화에 적용시켰다. 그 결과 유전자 알고리즘이 조금 더 좋은 최적값을 보였으며 해석시간은 반응표면법을 적용 시켰을 경우가 훨씬 짧았다. 병렬처리 기법을 이용한 위성구조체의 최적설계에 있어 유전자 알고리즘은 해의 전역성에서 반응표면법은 시간의 효율성에서 각각 장점을 보였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.1
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• pp.26-35
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• 1987

As an attempt to make the multi-objection for the line design of the rope way, the resulted formulas from the catenary curve as exact ones were summarized, and it was found out that the Kuhn-Tucker's optimality conditions and regions of the objective functions can analytically be expressed with dimensionless parameters. The Pareto's optimum solution set was analytically obtained through the objective function-the minimum relation of $W^{*}$, and $W^{*}$ is a trade-off relation. From this, The dimension of a rope and the value of an initial tension that are the standard in design of the rope way were determined. It was concluded that $V^{*}$ should become minimum, and that the ratio of the dimension of rope to the value of and initial tension become larger than superposition factor corresponding to curve AB.to curve AB.