• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.629-632
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• 1986

Both combinatorial and parametric optimization are used in computer-aided design(CAD). The most commonly occuring parametric optimization problems in engineering design such as design of control systems, design of electric circuits are usually expressed either as differentiable or as nondifferentiable semi-infinite programming(SIP) problems. In this paper we express algorithms for a class of computer-aided design problems arising in control systems.

• 오토저널
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• 제5권1호
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• pp.63-78
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• 1983

As a basic study on the machine tools of modular structure, a Computer Aided Design of feed driving unit and an optimization of the dynamic characteristics of a machine tool structure are carried out.. Computer-aided design technique enables designers to save time and to easily do the job in variant design by effectively documenting design techniques and data. In this study a computer program package was developed for automatic design of a proper feed driving units by utilizing building block principle of OIWA CADET.

• Architectural research
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• 제15권4호
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• pp.207-214
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• 2013

A form-finding technique is proposed for three-dimensional spatial structures. Two-step discrete finite element (FE) mesh generator based on computer aided geometric design (CAGD) is introduced and used to control the shape of three-dimensional spatial structures. Mathematical programming technique is adopted to search new forms (or shapes) of spatial structures. For this purpose, the strain energy is introduced as the objective function to be minimized and the initial volume (or the initial weight) is considered as constraint function. Numerical examples are carried out to test the capability of the proposed form-finding techniques and provided as benchmark tests.

• Radiation Oncology Journal
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• 제10권1호
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• pp.95-100
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• 1992

LINAC 뇌정위적 방사선 수술은 multiple noncoplanar arc, 3 차원 선량 계산 및 많은 조사 변수들이 사용되기 때문에 간단한 경우에도 최적 선량분포를 얻기 위해서는 많은 시간이 요구된다. 본 논문에서는 실험적 방법과 분석적 방법을 통한 유용한 방법을 제시하기 위한 것으로서, 보다 자세한 방법 및 내용은 앞으로의 발표 논문에서 다루게 된다. 실험적 방법으로 2가지 방법에의하면, 첫번째 방법은 multiple isocenter를 이용하는 것이고, 두번째 방법은 beam's eye view와 field shaping을 이용한 conformal therapy이다. 분석적 방법은 최적 조사조건을 찾기 위하여 computer-aided design optimization 방법을 이용하는 것이다.

• 전산구조공학
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• 제10권2호
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• pp.233-242
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• 1997

이 논문은 연속보의 동적 최적설계에 관한 연구이다. 본 연구에서는 연속보의 근사적인 최적제원을 결정하기 위하여 컴퓨터 프로그램의 실행결과를 이용한 기법을 이용하였다. 경간길이, 질량 및 휨강성이 변화하는 연속보의 자유진동해석과 이동 집중하중이 작용하는 경우 동적응답해석을 실행할 수 있는 컴퓨터 프로그램을 개발하였다. 모형실험 결과와 이론적인 해석결과가 잘 일치하여 해석결과의 타당성을 검증할 수 있었다. 설계효율을 나타내기 위하여 최대 동적응력, 경간사이의 응력차이, 이동 집중하중이 작용하는 점에서의 rms 처짐 및 전체지간의 총질량 등 4가지의 무차원 변수들의 선형결합으로 이루어지는 최적함수를 정의하였다. 3경간 연속보에 대한 해석결과 개략적인 최적제원을 갖는 연속보로 설계하는 경우 등간격의 등단면 연속보에 비해 설계효율을 개선할 수 있음을 알 수 있었다.

• 대한조선학회지
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• 제10권1호
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• pp.1-14
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• 1973

In the Department of Naval Architecture, Seoul National University, the development of computer programs for the computer-aided ship design sponsored by the Ministry of Science and Technology has been begun. The project is to be accomplished as a four-year plan, and the results of the works of the first year, preliminary design of dry-cargo ships based on an optimization technique and some fundamental calculations accompanied with the basic design of ships such as calculations of displacement, hydrostatic characteristics of hull forms, stability, floodable length, load line and longitudinal section modulus, are given in the Report R-72-9[9] published by the sopnsor for the public interests. In this paper, the philosophy and methodological principles with which the preliminary design program given in Appendix II was developed are summerized.

• 대한조선학회논문집
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• 제46권1호
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• pp.87-95
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• 2009

The applicability of optimization techniques for hull surface fitting has been important in the ship design process. In this research, the Genetic Algorithm has been used as a searching technique for solving surface fitting problem and minimizing errors between B-spline surface and the ship's offset data. The encoded design variables are the location of the vertex points and parametric values. The sufficient accuracy in surface fitting implies not only various techniques for computer-aided design, but also the future production design.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 봄 학술발표회 논문집
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• pp.139-146
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• 1997

The main purpose of this paper is to investigate the near-optimal parameters of continuous beam subject to a moving load. The computer-aided optimization technique is used to obtain the near-optimal parameters. 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 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 by 12 to 24 percent when compared to a reference configuration beams of the same total span length.

• 대한기계학회논문집A
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• 제21권11호
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• pp.1773-1785
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• 1997

The cooling stage is the very critical and most time consuming stage of the injection molding process, thus it cleary affects both the productivity and the part quality. Even through there are several commercialized package programs available in the injection molding industry to analyze the cooling performance of the injection molding coling stage, optimization of the cooling system has npt yet been accomplished in the literature due to the difficulty in the sensitivity analysis. However, it would be greatly desirable for the mold cooling system designers to have a computer aided design system for the cooling stage. With this in mind, the present study has successfully developed an interated computer aided design system for the injection molding cooling system. The CAD system utilizes the sensitivity analysis via a Boundary Element Method, which we recently developed, and the well-known CONMIN alforuthm as an optimization technique to minimize a weighted combination (objective function) of the temperature non-uniformity over the part surface and the cooling time related to the productivity with side constranits for the design reality. In the proposed objective function , the weighting parameter between the temperature non-uniiformity abd the cooling time can be adjusted according to user's interest. In this cooling system optimization, various design variable are considered as follows : (i) (design variables related to processing conditions) inlet coolant bulk temperature and volumetric flow rate of each cooling channel, and (ii) (design variables related to mold cooling system design) radius and location of each cooling channel. For this optimum design problem, three different radius and location of each cooling channel. For this optimum design problem, three different strategies are suffested based upon the nature of design variables. Three sample problems were successfully solved to demonstrated the efficiency and the usefulness of the CAD system.

• 한국공간구조학회논문집
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• 제10권2호
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• pp.77-86
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• 2010

본 연구에서는 프리폼(free form)을 가지는 공간구조물의 유한요소망을 자동으로 생성하는 기법을 개발하고 그 배경이론과 수치실험 결과 그리고 이용방안에 대하여 기술하였다. 본 연구를 통하여 제시한 유한요소망 생성기법은 공간구조물의 해석을 위해 전통적으로 이용하던 형태별 자동생성기법의 한계를 극복하기 위하여 개발 되었다. 개발된 자동 생성기법은 최근 연속체 쉘 구조물의 형태를 정확히 구현하기 위해 활발히 이용되고 있는 CAGD기법을 도입하였다. 본 연구에서 제시된 자동생성기법은 두 단계의 생성과정을 거치는데 첫 번째가 구조물의 형태를 기하학적인 모델로 표현하는 단계이며 두 번째가 표현된 기하학적인 모델에 이산화된 공간구조물을 생성하는 단계이다. 수치실험을 통하여 본 연구에서 개발된 자동생성기법이 임의의 형상을 가지는 이산화된 공간구조물을 표현하기 용이할 뿐만이 아니라 기존의 자동생성기법을 수정 이용할 수 있는 장점이 있으며 특히 이산화된 공간구조물의 형상최적화에도 효과적으로 이용될 수 있을 것으로 나타났다.