• 품질경영학회지
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• 제42권4호
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• pp.757-768
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• 2014

Purpose: In this paper we present a case study of developing fast curing adhesives for insulation material of LNG carriers using an extreme vertices design with four mixture components. Three material properties are considered - shear strength, viscosity, and tensile strength. In the optimization experiment, we used hardness instead of tensile strength due to shortage of specimens. Methods: We employ four-factor extreme vertices design with 19 runs and desirability function approach for simultaneously optimizing three responses. After selecting optimal condition of the mixture components, we do confirmation experiments to verify the reproducibility of the optimal condition under manufacturing circumstance. Results: Simultaneous optimal condition for the three responses, that is, shear strength, viscosity, and harness is obtained. At the optimal condition, confirmation experiments are executed in manufacturing circumstance. The variation for the shear strength is not satisfactory, which is due to the variation of the humidity. Conclusion: At the optimal condition three material properties are satisfactory. To reduce the variability for the shear strength, robust design is needed.

• 한국전산구조공학회논문집
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• 제31권6호
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• pp.301-308
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• 2018

이 논문에서는 다중 재난을 고려한 복합 구조제어 시스템의 최적 설계방법을 제시한다. 한 가지 유형의 위험에 대해 하나의 시스템이 설계되는 전형적인 구조제어 시스템과는 달리, 구조물의 지진 및 바람에 의한 진동응답을 저감하기 위해 능동 및 수동제어 시스템에 대한 동시 최적 설계방법을 제안하였다. 수치 예로서, 30층 빌딩 구조물에 설치된 30개의 점성 댐퍼와 복합형 질량 감쇠기에 대한 최적 설계문제를 보였다. 최적화 문제를 풀기 위해 자체적응 화음탐색(harmony search, HS)알고리즘을 채택하였다. 화음탐색 알고리즘은 사람이 연주하는 악기의 튜닝 과정을 모방한 전역 최적화를 위한 메타 휴리스틱 진화 연산방법의 하나이다. 또한 전역 탐색 및 빠른 수렴을 위해 자가적응적이고 동적인 매개변수 조정 알고리즘을 도입하였다. 최적화 설계 결과, 능동 및 수동 시스템이 독립적으로 최적화된 표준적인 복합제어 시스템에 비해 제안한 동시 최적제어 시스템의 성능과 효율성이 우수함을 보였다.

• 전산구조공학
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• 제9권3호
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• pp.179-186
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• 1996

본 연구에서는 구조체의 위상학적 최적화를 위한 비선형 formulation(NLP)가 개발, 검토되었다. 이 NLP는 multiple-loading하에서 임의의 오브젝티브 함수, 응력, 변위 제약조건들을 쉽게 다룰 수가 있다. 또한 이 NLP는 해석과 최적화 디자인을 동시에 실시함으로써 요소 사이즈가 영으로 접근함에 따른 강성 매트릭스의 singularity를 피할 수 있다. 즉, 평형 방정식을 등제약조건으로 치환함으로써 강성 매트릭스 그 자체나 그의 역매트릭스를 구할 필요도 없어진다. 이 NLP는 multiple-loading conditon하에서 테스트되었으며, 이를 통해 이 NLP가 다양한 제약조건하에서 강력하게 작용함이 입증되었다.

• Composites Research
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• 제20권1호
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• pp.1-7
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• 2007

본 논문에서는 골프클럽샤프트의 정적특성의 최적화 방법론을 제시하였다. 복합재료를 사용한 샤프트의 최적성능향상을 위한 쉬트 프리프레그의 적층순서를 구하였다. 클럽샤프트의 굽힘 강성과 비틀림 강성의 동시 최적화를 위하여 새로운 최적화 목적함수를 제시하였다. 샤프트의 정적특성 분석을 위하여 고전적층 이론을 적용하였으며 최적화 방법으로서 적층순서를 설계변수로 정의하는 유전알고리즘을 사용하였다. 또한 얻어진 최적적층순서를 바탕으로 한 샤프트의 동적특성을 분석하였다.

• 한국생물정보학회:학술대회논문집
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• 한국생물정보시스템생물학회 2005년도 BIOINFO 2005
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• pp.57-62
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• 2005

Microarray gene expression profiling technology is one of the most important research topics in clinical diagnosis of disease. Given thousands of genes, only a small number of them show strong correlation with a certain phenotype. To identify such an optimal subset from thousands of genes is intractable, which plays a crucial role when classify multiple-class genes express models from tumor samples. This paper proposes an efficient classifier design method to simultaneously select the most relevant genes using an intelligent genetic algorithm (IGA) and design an accurate classifier using Support Vector Machine (SVM). IGA with an intelligent crossover operation based on orthogonal experimental design can efficiently solve large-scale parameter optimization problems. Therefore, the parameters of SVM as well as the binary parameters for gene selection are all encoded in a chromosome to achieve simultaneous optimization of gene selection and the associated SVM for accurate tumor classification. The effectiveness of the proposed method IGA/SVM is evaluated using four benchmark datasets. It is shown by computer simulation that IGA/SVM performs better than the existing method in terms of classification accuracy.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.979-983
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• 2001

We develop a new method of simultaneous optimization of trajectory and shape of redundant flexible manipulators for collision-free utilizing the B-spline function and a mathematical programming method We adopt an approximate flexible manipulator model which consists of rigid bar elements and spring elements. We use B-spline function for determining the approximate trajectory and the expressions of the outline of obstacles. The used total performance index consists of 2 performance indices. The first is the driving energy, and the second is the trajectory deviation which is caused by the approximate modeling for the flexible manipulator. We design optimal collision-free trajectory of flexible manipulators by searching optimum positions of the control points for B-spline approximation which minimize the performance index subject to constraint condition for collision-free. Some examinations through numerical examples show the effectiveness of the method

• 대한산업공학회지
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• 제39권6호
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• pp.554-561
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• 2013

As a special topic of the vehicle routing problems (VRP), VRPSDP extends the vehicle routing problem as considering simultaneous pickup and delivery for goods. The past studies have mainly dealt with a only weight constraint of a loading capacity for heterogeneous products. However. this study suggests VRPSDP considering separate loading area according to characteristics of loading species. The objective is to design a set of minimum distance routes for the vehicle routing assignment with independent capacity for heterogeneous species. And then we present a another HVRPSDP model which is easy to utilizes in a unique circumstance that is a guarantee of executing a task simultaneously from the various areas under restricted time and raising an application of vehicles that returns at the depot for the next mission like the military group. The optimal results of the suggested mathematical models are solved by the ILOG CPLEX software ver. 12.4 that is provided by IBM company.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.730-739
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• 2005

A common problem encountered in product or process design is the selection of optimal parameter levels which involve simultaneous consideration of multiresponse variables. A multiresponse problem is solved through three major stages: data collection, model building, and optimization. To date, various methods have been proposed for the optimization stage, including the desirability function approach and loss function approach. In this paper, we first propose a framework classifying the existing studies and then propose some promising directions for future research.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2006년도 추계학술대회
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• pp.377-380
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• 2006

A common problem encountered in product or process design is the selection of optimal parameter levels which involve simultaneous consideration of multiresponse variables. To date, various methods have been proposed for multiresponse optimization. In this paper, we briefly review the existing methods and then discuss some recent advances in this field.

• Management Science and Financial Engineering
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• 제14권2호
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• pp.45-66
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• 2008

Refuse collection, one of important elements in reverse logistics, is an activity rendering recyclables or wastes and moving them to some points where further treatment is required. Among various decisions in the collection activity, we focus on network design, which is the problem of locating collection points as well as allocating refuses at demand points to collection points while satisfying the capacity restriction at each collection point. Here, the collection point is the place where recyclables or wastes near the point are gathered, and locating the collection points is done by selecting them from a given set of potential sites. The objective is to minimize the sum of fixed costs to open collection points and transportation costs to move refuses from demand points to collection points. An integer programming model is developed to represent the problem mathematically and due to the complexity of the problem, two types of heuristics, one with simultaneous and the others with separate location and allocation, are suggested. Computational experiments were done on test problems up to 500 potential sites, and the results are reported. In particular, some heuristics gave near optimal solutions for small-size test problems, i.e., 2% gaps in average from the optimal solution values.