• 한국기계가공학회지
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• 제14권3호
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• pp.85-91
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• 2015

The press-fit shaft is an important part used in automobiles, vessels, and trains. This study proposes an optimized design method to reduce damage that may occur in the press-fitted shaft by modifying the shape of the boss step of the press-fitted shaft. To reduce the time and cost of running the optimized design method, an approximate design optimization is applied and an optimized algorithm is generated using a genetic algorithm that is widely used in engineering fields and an approximate model using a response surface method. The planned experiments for the data that are needed to generate the approximate model use a central composite design (CCD) and Latin hypercube sampling (LHS), and the results of the approximate optimization using the above two design of experiments are to be compared.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.278-282
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• 2003

There is a strong industrial demands for the development of light-vehicle to improve fuel efficiency. It is more effective to reduce weight of the parts directly driven by an automobile engine. So the saving in weight of wheels which is operated by an automobile engine improve fuel efficiency more than other parts. There are many step of sheet metal forming in fabricating automotive wheel, so that it is difficult to design process and tools of multi-stage stamping. Traditionally, design process and tools have depended on the experience of skilled workers and it has done by trial and error methods. However, it needs too much costs and time. Taguchi methods has an advantage of the number of required experiments and reliability compared with trial and error method. In this study, Taguchi methods and response surface methods are applied to design process and tools of automotive wheel. As a result, the principal variables are selected and process conditions are optimized.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제4B권2호
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• pp.39-46
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• 2004

Modern users demand that the on and off type solenoid actuator should be smaller, lighter in weight, lower in consumption power, and higher in response time. The complete design satisfying such requirements can be achieved when electromagnetic theories and empirical knowledge are combined. This paper presents various types of empirical coefficients essentially needed for optimal design of a solenoid actuator. The values of these empirical coefficients are obtained through extensive experiments over a great length of time for various kinds of solenoid actuators. We have developed a design program that is composed by combination of governing equations and empirical coefficients, and have also manufactured a prototype solenoid actuator based on the final results of the design program. The propriety of the design program and empirical coefficients have been proven by experiments.

• 한국기계가공학회지
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• 제6권4호
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• pp.65-70
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• 2007

In this study, we analyzed about that after design form manufacture master pattern in Rapid Prototyping-RP through design program, processes to manufacture prototype using Vacuum Casting. In Rapid Prototyping-RP, there is an en-or by shrinkage of resin and, in Vacuum Casting, there is an error by shrinkage of silicon. To select condition which shrinkage become the minimum of each process, manufactured prototype after using Full Factorial Design of Design of Experiments, We could confirm shrinkage using reverse engineering and that result came into effect ANOVA 2-way. We applied errors of each process to master pattern, and then presented the method to improve flood control precision of prototype of Vacuum Casting.

• 한국해안해양공학회:학술대회논문집
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• 한국해안해양공학회 2002년도 한국해안해양공학발표논문집 Proceedings of Coastal and Ocean Engineering in Korea
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• pp.1-13
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• 2002

For design of maritime structure, it is necessary to evaluate the effect and stability of the structure against wave action. Laboratory model experiments and their empirical formulas are mainly used to estimate those at present, although empirical formulas have a problem of accuracy and hydraulic experiments of cost and duration. In addition, performance-based design, which may be popularized as a new design concept in the near future, requires much more information than that obtained by empirical formulas and laboratory tests. Thus, numerical simulation may become more important hereafter for structure design. (omitted)

• International Journal of Fluid Machinery and Systems
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• 제4권1호
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• pp.14-24
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• 2011

In this paper, design optimization for mixed-flow pump impellers and diffusers has been studied using a commercial computational fluid dynamics (CFD) code and DOE (design of experiments). We also discussed how to improve the performance of the mixed-flow pump by designing the impeller and diffuser. Geometric design variables were defined by the vane plane development, which indicates the blade-angle distributions and length of the impeller and diffusers. The vane plane development was controlled using the blade-angle in a fixed meridional shape. First, the design optimization of the defined impeller geometric variables was achieved, and then the flow characteristics were analyzed in the point of incidence angle at the diffuser leading edge for the optimized impeller. Next, design optimizations of the defined diffuser shape variables were performed. The importance of the geometric design variables was analyzed using $2^k$ factorial designs, and the design optimization of the geometric variables was determined using the response surface method (RSM). The objective functions were defined as the total head and the total efficiency at the design flow rate. Based on the comparison of CFD results between the optimized pump and base design models, the reason for the performance improvement was discussed.

• 공업화학
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• 제32권6호
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• pp.621-626
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• 2021

MOF-801 합성공정의 최적화를 위해 순차적인 실험 계획법을 이용하였다. 먼저 screening을 위한 완전 2-요인 설계와 이후 반응표면 분석법 중에 하나인 중심합성 계획법을 연속적으로 사용하였다. 두 가지 반응변수인 MOF-801의 결정화도와 BET 비표면적 중에 실험계획법에 보다 적합한 변수를 선택하기 위하여 fumaric acid, dimethylformamide (DMF) 및 formic acid의 몰비를 이용한 2³ 요인 설계법을 수행하였다. MINITAB 19 소프트웨어에 따라 설계된 8번의 MOF-801 합성 실험을 수행한 이후 XRD 분석 및 질소흡착법을 이용하여 특성분석을 수행하였다. 두 가지 반응변수 중 결정화도의 R²이 0.999로 BET 비표면적보다 실험계획법에 보다 적합하였다. 분산 분석(ANOVA)을 통해 fumaric acid와 formic acid의 몰 비가 MOF-801의 결정화도를 결정하는 주요 인자임을 확인하였다. response optimization과 두 인자의 contour plot을 통해 최적의 몰비는 ZrOCl₂·8H₂O : fumaric acid : DMF : formic acid = 1 : 1: 39 : 35로 추정되었다. 이후 합성반응 공정의 최적화를 위해 도출된 전구체의 몰 비 조건에서 합성 기간과 온도에 대한 박스-벤켄설계법을 수행하였다. 설계된 9번의 합성실험을 통해 도출된 결과를 2차 모델 방정식을 이용하여 계산하였다. 이를 이용하여 MOF-801의 최대 결정화도는 합성시간 7.8 h 그리고 합성온도 123 ℃의 조건에서 얻을 수 있음을 예측하였다.

• 대한기계학회논문집A
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• 제38권5호
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• pp.489-495
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• 2014

마이크로 유전알고리즘은 적은 수의 개체 사용 및 무작위 개체 구성을 통한 돌연변이 기능 대체의 특징을 갖는 진화연산을 수행하여 일반적인 유전알고리즘이 갖는 각 세대당 많은 계산 량이 요구되는 단점을 극복하고자 하였다. 이러한 마이크로 알고리즘은 특히 설계변수가 3~5 개를 갖는 문제에 효율적이라는 것이 많은 연구자들에 의하여 알려졌다. 따라서 본 연구의 목적은 순차적 실험계획법과 마이크로 유전알고리즘을 이용한 최적화 알고리즘을 개발하는 것이며, 이를 수학예제와 구조물 문제에 적용하여 실용성을 확인하고자 한다. 순차적 실험계획법은 저자들의 선행연구에서 제안되었으며, 실험계획법과 반응표면법을 이용하는 근사최적화 기법에 의한 시행착오적인 반복과정을 최소화하고자 하는 방법으로써, 행렬실험과 평균분석을 반복 적용하는 개념이다.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1996년도 추계학술대회논문집
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• pp.47-55
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• 1996

This study developed a comprehensive and easily applicable nuclear reactor control system evaluation method using reactor operators behavioral and mental workload database. A proposed control panel design cycle consists of the 5 steps: (1) finding out inconvenient, erroneous, and mentally stressful factors for the proposed design through evaluative experiments, (2) drafting improved design alternatives considering detective factors found out in the step (1), (3) comparative experiements for the design alternatives, (4) selecting a best design alternative, (5) returning to the step (1) and repeating the design cycle. Reactor operators behavioral and mental workload database collected from evaluative experiments in the step (1) and comparative experiments in the step (3) of the design cycle have a key roll in finding out defective factors and yielding the criteria for selection of the proposed reactor control systems. The behavioral database was designed to include the major informations about reactor operators' control behaviors: beginning time of operations, involved displays, classification of observational behaviors, dehaviors, decisions, involved control devices, classification of control behaviors, communications, emotional status, opinions for man-machine interface, and system event log. The database for mental workload scored from various physiological variables-EEG, EOG, ECG, and respir- ation pattern-was developed to indicate the most stressful situation during reactor control operations and to give hints for defective design factors. An experimental test for the evaluation method applied to the Compact Nuclear Simulator (CNS) installed in Korea Atomic Energy Research Institute (KAERI) suggested that some defective design factors of analog indicators should be improved and that automatization of power control to a target level would give relaxation to the subject operators in stressful situation.

• 한국과학교육학회지
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• 제31권6호
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• pp.986-997
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• 2011

이 연구에서는 탐구학습에서 과학적 창의성을 계발하기 위해 활용할 수 있는 비유 실험 활동을 개발, 적용하여 비유 실험을 활용한 탐구학습이 중학교 1학년 과학영재 학생들의 실험설계 과정에 미치는 영향을 조사하였다. 과학영재 학생들의 실험설계 과정을 창의적 사고과정의 유형에 따라 분류하고 각 유형에 따른 특징 및 실험설계 과정요소별 수행수준을 분석하였다. 비유 실험을 활용한 실험설계 과정의 유형은 확장이동형, 후진-확산이동형, 제자리이동형의 세 가지 유형이 나타났다. 확장이동형은 대응 관계를 심층적으로 파악함으로써 새로운 관점에서 전반적으로 모든 과정요소를 고려하며 정교한 실험설계를 수행하였다. 후진-확산이동형은 비유 실험을 활용해 새로운 방향으로 관점을 전환하지만 대응의 수준이나 과정요소에 대한 고려에 미흡한 부분이 있어 실험설계의 구체성이 다소 부족한 것으로 나타났다. 제자리이동형은 기존의 관점을 새로운 문제 상황에 그대로 적용하고 필요한 과정요소를 고르게 고려하지 못하며 적절한 실험설계를 수행하지 못하는 것으로 나타났다. 이에 대한 교육적 함의를 논의하였다.