• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.3
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• pp.219-226
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• 2005

In this study, the problem formulation and solution technique using genetic algorithms for design optimization of laminate composite cylindrical beam section are presented. The hollow cylindrical beams we usually used in the wheel chair. If the weight of wheel chair is reduced, it will lead to huge improvement in passenger's mobility and comfort. In this context, the replacement of steel by high performance and light weight composite material along with optimal design will be a good contribution in the process of weight reduction of a wheel chair. An artificial genetics approach for the design optimization of hollow cylindrical composite beam is presented. On applying the genetic algorithm, the optimal dimensions of hollow cylindrical composite beams which have equivalent rigidities to those of corresponding hollow cylindrical steel beams are obtained. Also structural analysis is conducted on the entire wheel chair structure incorporating Tsai-Wu failure criteria. The maximum Tsai-Wu failure criteria index is $0.192\times10^{-3}$ which is moth less than value of 1.00 indicating no failure is observed under excessive loading condition. It is found that the substitution of steel by composite material could reduce the weight of wheel chair up to 45%.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.11
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• pp.973-982
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• 2007

In this paper, optimal design framework is developed by automatic mesh generation and PSO(Particle Swarm Optimization) algorithm based on parallel computing environment and applied to structural optimal design of satellite adapter module. By applying automatic mesh generation, it became possible to change the structural shape of adapter module. PSO algorithm was merged with parallel computing environment and for maximizing a computing performance, asynchronous PSO algorithm was developed and could reduce the computing time of optimization process. As constraint conditions, eigen-frequency and maximum stress was considered. Finally using optimal design framework, weight reduction of satellite adapter module is derived with satisfaction of structural safety.

• Journal of the KSME
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• v.35 no.8
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• pp.709-715
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• 1995

날로 그 중요성이 대두되고 있는 환경보존 문제에 능동적으로 대응하고 여러 계층 소비자의 안 전도, 쾌적성 등에 관련된 요구, 성능의 수준향상에 효과적으로 대처하기 위해서는 차량의 경량화 기술이 가장 먼저 선행되어야 할 과제이다. 경량화를 추구하는 방법은 최적설계 개념을 이용한 구조합리화에 의한 방법과 알루미늄, 강화 플라스틱 등 신소재 대체에 의한 방법이 병행 연구 되고 있다. 이 글에서는 구조합리화를 통한 경량화 목표를 달성하기 위해 설계 초기 단계에 활용 가능한 단순 보 모델 개발의 필요성에 관해 언급하고 실차의 도어 측면 붕괴강도(door side intrusion strength), 루프 붕괴강도 (roof crush strength) 해석을 위한 단순 보 모델 개발에 관해 소개하고자 한다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.96-97
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• 2003

인공위성 카메라에 장착되는 반사경의 경우 광학적 상의 열화에 영향을 미치는 자체 변형을 최소화하기 위해 경량화와 함께 높은 강성이 유지되도록 설계하여야 한다. 이를 위하여 일반적으로 반사경의 하판의 형상을 벌집구조로 만들거나 단일아치나 이중아치로 만드는 경우가 많다. 예로 벌집구조를 가진 경량화 반사경의 형상을 그림 1에, 경량화 형상을 정의하기 위한 기하학적 변수를 그림 2에 나타내었다. 여러 가지 반사경 형상에 따른 광학적 성능비교가 Valent와 Vukobratovich에 의해 시도되었다. (중략)

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.682-685
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• 2014

In this paper, an improved designed of the circularly polarization antenna for sensor node. Stochastic optimization algorithms of Particle Swarm Optimization (PSO) and Adaptive Particle Swam Optimization(APSO) are studied and compared. To verify that the APSO is working better than the standard PSO, the design of a circularly polarization antenna is shows the optimized result with 27 iterations in the APSO and 41 iterations in th PSO.

• Computational Structural Engineering
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• v.6 no.1
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• pp.117-125
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• 1993

In general, the strength and stiffness of laminated composite cylindrical shells are very sensitive to the variation of slenderness parameters, some coupling-stiffness parameters, lamination angles, stacking sequence and number of layers. In this paper, the effects of these factors on the strength and buckling reliabilities of GFRP laminated cylindrical shells are investigated based on the proposed strength and buckling limit state models. As these factors have various and complicated effects on the strength and buckling reliabilities of GFRP laminated cylindrical shells, the results should be incorporated into the design formula such that optimum design technique and design code which provide uniform consistent reliability for balanced design in practice

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.5
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• pp.38-44
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• 2015

In this paper, the vibration control effect of the Exo-type damping system was investigated by applying the Kagome dampers to 15-story and 20-story frame structure apartment. A new Exo-type damping system composed of the dampers and supporting column was proposed in the previous work and numerical analysis were performed to investigate the effects of optimum stiffness ratio between controlled structure and supporting column, the size of damper and yield ratio of the damper. The numerical analysis results of a structure with Exo-type damping system up to the third story showed that the stiffness ratio should be higher than 7.0 and the damper device yield ratio be at least 8.0% ($V_{damper}/V_{base\;shear$) to effectively reduce the base shear and the maximum drift of the uppermost story. When the Exo-type damping system was installed up to the fifth story, the stiffness ratio should be higher than 2.5 and damper device yield ratio needs to be at least 3.5% ($V_{damper}/V_{base\;shear$) for obtaining the target performance.

• Journal of Korean Society of Steel Construction
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• v.16 no.2 s.69
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• pp.201-213
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• 2004

A GA-based optimum design algorithm and a program for plane steel frame structures with semi-rigid connections are presented. The algorithm is incorporated with the refined plastic hinge analysis method wherein geometric nonlinearity is considered by using the stability functions of beam-column members, and material nonlinearity, by using the gradual stiffness degradation model that includes the effects of residual stresses, moment redistribution through the occurrence of plastic hinges, semi-rigid connections, and geometric imperfection of members. In the genetic algorithm, the tournament selection method and micro-GAs are employed. The fitness function for the genetic algorithm is expressed as an unconstrained function composed of objective and penalty functions. The objective and penalty functions are expressed as the weight of steel frames and the constraint functions, respectively. In particular, the constraint functions fulfill the requirements of load-carrying capacity, serviceability, ductility, and construction workability. To verify the appropriateness of the present method, the optimal design results of two plane steel frames with rigid and semi-rigid connections are compared.

• Journal of the Korean GEO-environmental Society
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• v.5 no.1
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• pp.13-25
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• 2004

Granular compaction piles increase the load bearing capacity of the soft ground and reduce the settlement of foundation built on the reinforced soil. The granular compaction group piles also accelerate the consolidation of the soft ground and prevent the liquefaction caused by earthquake using the granular materials such as sand, gravel, stone etc. However, this method is one of unuseful method in Korea. In the present study, the optimum locations of granular compaction group piles using genetic algorithm are proposed. The results were shown that the bearing capacity was increased in the case concentrated on the central part of the group piles. Also, the optimum design for total weight of granular compaction group piles was carried out in consideration of the economical efficiency and parametric studies were performed to examine the effects of parameters at the design of granular compaction group piles.

• Computational Structural Engineering
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• v.10 no.2
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• pp.233-242
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• 1997

The main purpose of this paper is to investigate the dynamic optimal design of continuous beams. The computer-aided optimization technique is used to obtain the near-optimal parameters of continuous beam. The computer program is developed to obtain the natural frequency parameters and the forced vibration responses to a transit point load for the continuous beam with variable support spacing, mass and stiffness. The model test data is in good agreement with the computer calculation, which serves to validate the mathematical analysis. The optimization function to describe the design efficiency is defined as a linear combination of four dimensionless span characteristics; the maximum dynamic stress; the stress difference between span segments; the rms deflection under the transit point load; and the total span mass. Studies of three span beams show that the beam with near-optimal parameters can improve design efficiency when compared to a uniform beam with even spacing of the same total span length.