• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.5
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• pp.543-551
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• 2011

The paper deals with the comparative study of design optimization based on various approximation techniques in strength design of riser support structure installed on floating production storage and offloading unit(FPSO) using offshore operation loading conditions. The design optimization problem is formulated such that structural member sizing variables are determined by minimizing the weight of riser support structure subject to the constraints of structural strength in terms of loading conditions. The approximation techniques used in the comparative study are response surface method based sequential approximate optimization(RBSAO), Kriging based sequential approximate optimization(KBSAO), and the enhanced moving least squares method(MLSM) based approximate optimization such as CF(constraint feasible)-MLSM and Post-MLSM. Commercial process integration and design optimization(PIDO) tools are employed for the applications of RBSAO and KBSAO. The enhanced MLSM based approximate optimization techniques are newly developed to ensure the constraint feasibility. In the context of numerical performances such as design solution and computational cost, the solution results from approximate techniques based design optimization are compared to actual non-approximate design optimization.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.476-479
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• 2009

Unison의 U50 풍력발전기는 실증실험을 거쳐서 상용화 되어 시장에 제품으로 나와 있다. U50에 사용되는 영구자석 동기발전기는 Stator 내경 3.32 m 로 84극을 가지고 있으며 정격 25 rpm으로 운전되는 직접구동형이다. 직접구동형 발전기는 Gearbox 가 불필요한 반면에 높은 torque로 인해서 발전기가 무거운 단점이 있다. 기존의 U50 에 사용되는 발전기는 지지 구조물까지 포함할 경우 총중량이 약 20톤 이상이다. 발전기의 중량을 줄이고 경량화 시키기 위하여 slot에 들어가는 Ampere turn을 증가시키고 turn 수를 증가시켜서 기존과 유사한 전압, 전류, 출력을 유지하면서 축방향 Stator 길이를 감소시킨 최적화 모델에 대한 설계에 대하셔 연구를 진행하였으며 이 보고에서는 그 결과와 절차에 대해서 요약한다.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.158-165
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• 2006

Lithography 장비의 국내 기술개발 수준은 선진사에 비해 많이 뒤져있다고 볼 수 있다. 최근 디스플레이 산업의 폭발적인 성장과 더불어 보다 확실하고 안정적인 생산을 위해서는 Lithography 장비의 국산화 기술개발이 시급한 상황이다. 현재 시중에 나와 있는 제품의 경우 Mask holder part의 과도한 중량으로 인해 교체의 어려움이 있고 그로 인해 장비의 자동화에 걸림돌이 되고 있는 상황이다. 이에 따라 Mask holder part의 교체를 양호하게 하기 위해 질량을 줄이고 처짐이 적게 발생할 수 있도록 형상을 최적화 시키는 것에 목적을 두고 실험계획법 중의 하나인 Taguchi method를 활용하여 Mask holder part의 형상을 최적화하였다.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.10
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• pp.135-142
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• 2019

Ant colony optimization(ACO) technique is utilized in truss size optimization with frequency constraints. Total weight of truss to be minimized is considered as the objective function and multiple natural frequencies are adopted as constraints. The modified traveling salesman problem(TSP) is adopted and total length of the TSP tour is interpreted as the weight of the structure. The present ACO-based design optimization procedure uses discrete design variables and the penalty function is introduced to enforce design constraints during optimization process. Three numerical examples are carried out to verify the capability of ACO in truss optimization with frequency constraints. From numerical results, the present ACO is a very effective way of finding optimum design of truss structures in free vibration. Finally, we provide the present numerical results as future reference solutions.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.186-190
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• 2018

This study was investigated changes of physical properties of soybean sprout by changing single or combinations of parameters in each manufacturing process. In blanching, use of sugar solution and decrease of blanching time reduced hypocotyl diameter and weight loss of soybean sprouts. However, single application among parameters in pre-treatment did not induce significant changes in soybean sprout during cooking of frozen product. The control process was blanching with water, seasoning with salt and sugar, and adding cooked rice with mixing type. Combinations of parameters, which were blanching with sugar solution, seasoning with sugar, and adding cooked rice with topping type, induced significantly higher shear force values ($592{\pm}21g$), larger diameter ($1.58{\pm}0.14mm$), and less weight loss ($13.4{\pm}3.0%$) of soybean sprouts during cooking of frozen product than those from the control process ($498{\pm}24g$, $1.35{\pm}0.13mm$, and $16.0{\pm}1.7%$, respectively) (p<0.05).

• Journal of Korean Society of Steel Construction
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• v.12 no.1 s.44
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• pp.93-102
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• 2000

Substructuring-based hierarchical approach for design analysis and optimization of structural frames is presented in this study. The conceptual framework of this method is in the hierarchical modeling for design processes as well as structural systems and the methodology combining substructuring analysis and multilevel optimization. Mathematical models for analysis and synthesis are established on the common basis of substructuring systems. Modularized behavioral analysis, design sensitivity analysis and optimization are linked and integrated on the mathematical and structural basis of substructuring. Substructures are coordinated with the active constraints for system level and the weight ratio criteria. Numerical examples for test frames show the validity and effectiveness of the present approach.

• Journal of Korean Society of Steel Construction
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• v.9 no.3 s.32
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• pp.457-465
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• 1997

The Shape optimization makes it possible to reduce the weight of structure and cost then member sizing optimization. A vast amount of imprecise information is existed in constraints of the optimum design. It is very difficult and sometimes confusing to describe and to deal with the several criteria which contain fuzzy degrees of relatives importance. This paper proposed weighting strategies in the multiobjective shape optimization of fuzzy structural system by ${\alpha}$-cut approach. The algorithm in this research is numerically tested for 2-bar truss structure. The result show that. the user can choose the one optimum solution in practices as obtaining the optimum solutions according to the ${\alpha}$-cut approach, weight of volume and displacement.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1381-1388
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• 2011

Recently, Because of weight lighting and tighten safety regulations of the railway vehicle railroad weight lighting and safety improvement technology is internationally required. Slide step for moving the passenger to high flatform in the railroad vehicle is recognized of important parts. However, Due to high price and weight, it is limited. In this research, In order to apply for railroad, it was redesigned to optimize part count and reduce the price and weight. By choosing honeycombcore as a part for enduring high weight and weight lighting, We produce honeycombpanel of sandwich structure which a different kind connected by using existing stainless(STS304)steel and thermo plasticity glue. Finally, we can find that honeycombpanel is suitable for weight lighting and high weight. As well as, with test result, we can prove that low-high platform railway system will be optimized, if steps are applied to honeycombpanel.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.403-411
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• 2020

This paper discusses the main findings of the development of the twin-hull Car ferry for island freight and passenger transport. The final model had a 19 m wide beam to create enough space for cars on the deck area and thus, enhance the economic feasibility in the market. The vessel had a V-shape with a bulbous bow to minimize the wave-making resistance and the hydrodynamic performance of the ship was verified through computational fluid dynamics. Multi-objective optimization problems of Pareto simulated annealing were used to achieve a weight reduction of approximately 3.9 % and reduce the manufacturing cost. The main results obtained in this study are expected to be useful to engineers and professionals in related industries interested in research on twin catamaran.

• Journal of Korean Society of Steel Construction
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• v.23 no.5
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• pp.581-593
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• 2011

The underlying advantages of using thin-walled corrugatedwebs instead of plate girders with stiffeners are the elimination of instability problems associated with buckling of the thin-walled flat plate, and elimination of the need for transverse stiffeners, which alsoresults in economic advantages. This paper focuses on two aspects related to the structural design technique forsinusoidal corrugated web steel beams, and the optimum design of the beams using real-value genetic algorithms. The structural design process and design variables used in this optimization werecomposed with EN 1993-1-5, DASt-R015 standard and Pasternak et al. (2004), and the valid design capacity of shear buckling of the standards were compared. For the optimum structural design, the objective function, presented as the fullweight of the sinusoidal corrugated web beams, and the slenderness, member forces, and maximum deflection of the beam, were considered constraints. Finally, the simple beam under the uniform load was adopted as a numerical example, and the effective probability parameters of the genetic operators were considered to find the global minimum point.