• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.118-123
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• 2004

In this study, genetic algorithm mixed binary and real encoding is proposed to deal with design variables of various types. And that is applied to optimum design of Multi-stage gear drive. Design of pressure vessel which is mixed discrete and continuous variables is applied to verify reasonableness of proposed genetic algorithm. The proposed genetic algorithm is applied for the gear ratio optimization and the volume minimization of geared motor which is used in field. In result, it shows that the volume has decreased about 8% compared with the existing geared motor.

• 한국가스학회지
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• 제5권1호
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• pp.21-28
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• 2001

회분식 공정의 HAZOP 분석 전문가 시스템은 연속 공정의 HAZOP 분석 기법과는 달리 time과 sequence라는 이산적인 변수들을 고려해야 한다. 따라서 본 연구에서는 이산 변수들과 연속 변수들의 관계를 이용하여 회분식 공정의 time과 sequence 해석을 수행하는 회분식 공정의 HAZOP 분석 자동화를 위한 전문가 시스템을 개발하였다. 제안된 전문가 시스템을 Latex 제조 공정에 적용하여 그 실효성을 검토하였다.

• 한국가스학회지
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• 제3권2호
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• pp.34-42
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• 1999

회분식 공정의 HAZOP 분석 기법은 연속 공정의 HAZOP 분석 기법과는 달리 time과 sequence라는 이산적인 변수들을 고려해야 한다. 회분식 공정의 time과 sequence 해석은 연속 공정의 HAZOP 분석 기법으로는 설명될 수 없으므로, 이산 변수들과 연속 변수들의 관계를 이용하여 회분식 공정의 HAZOP 분석을 수행하는 방법을 개발하였다 본 연구에서는 이 방법을 Latex 제조 공정에 적용하여 그 실효성을 검토하였다.

• Journal of applied mathematics & informatics
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• 제24권1_2호
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• pp.399-409
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• 2007

In this paper we use iterative dynamic programming in the discrete case to solve a wide range of the nonlinear equations systems. First, by defining an error function, we transform the problem to an optimal control problem in discrete case. In using iterative dynamic programming to solve optimal control problems up to now, we have broken up the problem into a number of stages and assumed that the performance index could always be expressed explicitly in terms of the state variables at the last stage. This provided a scheme where we could proceed backwards in a systematic way, carrying out optimization at each stage. Suppose that the performance index can not be expressed in terms of the variables at the last stage only. In other words, suppose the performance index is also a function of controls and variables at the other stages. Then we have a nonseparable optimal control problem. Furthermore, we obtain the path from the initial point up to the approximate solution.

• 응용통계연구
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• 제7권2호
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• pp.225-237
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• 1994

본 연구에서는 핵확산 감시와 관련된 이상점 탐지를 위한 일반화 우도비 검정 방법이 개발되었다. 고전적인 이상점 탐지방법들이 연속형 변수만을 고려한 반면, 본 연구에서 제안된 방법은 연속형 변수, 이산형 변수, 혹은 이산형과 연속형이 혼합된 변수들에 모두 적용될 수 있다. 더우기 대부분의 고전적인 방법들에 있어서 주로 이용된 정규분포 가정을 필요로 하지 않는다. 본 연구에서 제안된 방법은 일반화 우도비에 붓스트랩 방법을 적용하여 구성되었다. 모의 실험을 통하여 검정력을 고찰함으로써 제안된 검정방법의 성능을 연구하였다.

• 한국항공운항학회지
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• 제21권2호
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• pp.7-14
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• 2013

In this paper, the optimal design of composite rotor blade cross-section is performed using a genetic algorithm. Skin thickness, torsion box thickness and skin lay-up angle are adopted as discrete design variables. The position and width of a torsion box are considered as continuous variables. An object function of optimal design is to minimize the mass of a rotor blade, and constraints are failure index, center mass, natural frequency and blade minimum mass per unit length. Finally, design variables such as the thickness and lay-up angles of a skin, and the thickness, position and width of a torsion box are determined by using an in-house program developed for the optimal design of rotor blade cross-section.

• 항공우주시스템공학회지
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• 제8권1호
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• pp.12-17
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• 2014

In this paper, optimal design of composite rotor blade cross-section to consider manufacturability was performed. Skin thickness, torsion box thickness and skin lay-up angle were adopted as discrete design variables and The position and width of a torsion box were considered as continuous variables. An object function of optimal design is to minimize the mass of a rotor blade, and various constraints such as failure index, center mass, shear center, natural frequency and blade minimum mass per unit length were adopted. Finally, design variables such as the thickness and lay-up angles of a skin, and the thickness, position and width of a torsion box were determined by using an in-house program developed for the optimal design of rotor blade cross-section.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.115-124
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• 2000

An efficient multi-level (EML) optimization algorithm using discrete variables of framed structures is proposed in this paper. For the efficiency of the proposed algorithm multi-level optimization techniques using a decomposition method that separates both system-level and element-level are incorporated in the algorithm In the system-level, to save the numerical efforts an efficient reanalysis technique through approximated structural responses such as moments and frequencies with respect to intermediate variables is proposed in the paper. Sensitivity analysis of dynamic structural response is executed by automatic differentiation (AD) that is a powerful technique for computing complex or implicit derivatives accurately and efficiently with minimal human effort. In the element-level, to use AISC W-sections a section search algorithm is introduced. The efficiency and robustness of the EML algorithm, compared with a conventional multi-level (CML) algorithm and single-level genetic algorithm is successfully demonstrated in the numerical examples.

• Communications for Statistical Applications and Methods
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• 제17권2호
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• pp.153-164
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• 2010

본 논문에서는 이산형과 연속형 데이터가 혼합되어 있는 데이터 구조를 탐색하기 위하여 동적 기법을 사용하였다. 이산형 변수들간의 관계를 표현하는 선 모자이크 도표와 연속형 변수들의 관계를 위한 산점도, 일변량 변수 관점에서의 데이터의 분포를 파악할 수 있는 상자도표를 동시에 사용하면서, 동적인 기법들을 적용하여 다차원 데이터에 대한 구조를 좀 더 쉽게 파악할 수 있음을 보였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.293-296
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• 1997

Robust stability conditions for discrete-time variable structure control is proposed. Conventionally the discrete-time variable structure control method with a variable structure uncertainty compensator approach requires a bounded changing rate of the uncertainties to ensure robust stability. However, when uncertainties vary as a function of state variables, which occur with parametric uncertainties, it is not reasonable to assume a bounded variation on the uncertainties. In this paper, uncertainties are assumed to consist of exogenous disturbances and parametric uncertainties. An uncertainty compensator is used to deal with the former, and a robust stability condition is derived using Small Gain Theorem for the latter.