• 한국해양공학회지
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• 제13권3호통권33호
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• pp.12-20
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• 1999

In this paper, method for mapping a three-dimensional shape into the two-dimensional plane will be introduced. This method is referred to geometric modelling and means a transformation between the flat sheet and final surface. The initial blank shape represents the original configuration of the final shape formed into three dimensional surface. The initial constant constant area mapping hypothesis was used in this paper. This technique will be applied to the basic data for an interactive computer design capable of dealing with typical stamping process, including deep parts and complex shapes.

• 한국군사과학기술학회지
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• 제16권2호
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• pp.101-110
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• 2013

This paper considers the many kinds of attitude control systems including launcher. JVC(Jet vane control), Jet tap, Jetvator and Movable nozzles are used to control the initial attitude of a missile only. Recently side jet thruster and it's applications to control initial turn and to maneuver at high altitude have been increased. How to design and develop the missile for an initial turn and a high maneuver at high altitude using side jet thrust were described in this paper.

• 한국건설순환자원학회논문집
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• 제9권3호
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• pp.236-245
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• 2021

노출 환경 및 설계 변수의 변화에 따라 내구수명은 큰 범위를 가지고 변화하게 되므로 설계자 입장에서는 내구수명의 변동성을 이해하는 것은 중요하다. 최근 들어 탄소 중립을 위하여 플라스틱 혼소재가 클링커 생산 시 원료로 사용되고 있는데, 이러한 경우, 시멘트의 염화물 함유량은 증가하게 된다. 본 연구의 목적은 플라스틱 혼소재를 사용하여 초기 염화물량이 증가할 경우, 다양한 노출 환경과 설계 변수를 고려하여 내구수명이 어떤 수준으로 변화하는지에 대한 연구이다. 이를 위해 4 수준의 초기 염화물량을 설정하였으며, 3 수준의 표면 염화물량을 포함한 다양한 환경 조건에 따라 내구수명을 LIFE 365 프로그램을 이용하여 평가하였다. 해석 변수로서 임계 염화물량, 고로슬래그 미분말 치환 혼입율, 물-결합재 비, 피복두께, 단위 결합재량, 초기 염화물량을 설정하였다. 초기 염화물량이 증가함에 따라 내구수명은 감소하는 경향을 보이지만 이 값을 1,000ppm까지 허용해도 내구수명의 큰 감소는 나타나지 않았다. 또한 슬래그 치환율을 증가시킬 경우 더 높은 내구수명을 확보할 수 있는데, 이는 고로슬래그 미분말이 외부 염화물 이온의 확산 저감과 동시에 자유 염화물을 고정시키는 효과가 있기 때문이다. 초기 염화물량의 허용 농도를 유럽기준과 같이 증가시키는 것도 지속가능성 향상과 탄소량을 저감시키는 데 도움이 될 것으로 판단된다. 또한 표면 염화물량이 낮고 혼화재(슬래그)를 사용한 경우, 초기 염화물량의 영향은 상대적으로 낮았지만 표면염화물량이 높은 경우, 노출환경을 고려한 신중한 배합설계가 필요하다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 추계학술대회 논문집
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• pp.281-285
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• 2001

The design of injection molded polymeric parts has been done empirically, since it requires profound knowledge about the moldability and causal effects on the properties of the part, which are not available to designers through current CAD systems. An interactive computer-based design system is developed in order to realize the concept of rational design for the productivity and quality of mold making. The knowledge-based CAD system is constructed by adding the knowledge-base module for mold feature synthesis and appropriate CAE programs for mold design analysis in order to provide designers, at the initial design stage, with comprehensive process knowledge for feature synthesis performance analysis and feature-based geometric modeling. A knowledge-based CAD system is a new tool which enables the concurrent design with integrated and balanced design decisions at the initial design stage of injection molding.

• International Journal of Aeronautical and Space Sciences
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• 제6권1호
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• pp.89-96
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• 2005

Ducted fans have advantages in noise as well as operational safety aspects compared to conventional tail rotors and are used as an anti-torque system for various classes of helicopters. The final goal of this study is to develop a ducted fan anti-torque system which can replace conventional tail rotors of existing helicopters to achieve safety enhancement and low noise level. In this paper, a conceptual design process and the results are described. Initially, the design requirement and the design parameter characteristics are analysed, and then initial sizing and configuration design are performed. There are several configuration changes due to specific technical reasons in each case. Finally, the required power and the pitch link load are predicted as an initial estimation. The conceptual design technique for the ducted fan in this study can be easily applied to the design of other ducted fans such as the lift fan for unmanned aerial vehicle.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.732-737
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• 2004

TTX(Tilting Train Express), which has improved traveling performance on curved track, is being designed in cope with future railway circumstance. Nowadays, in the world, many efforts are focussed on railway safety. Especially, a variety of researches on train crashworthiness have been conducted. As a part of these efforts, some equipments on TTX are designed to reduce fatalities and casualties in crash accidents. This paper introduces impact energy absorbtion characteristics on the initial design of the front end structure. Some comments are made briefly for improvement of initial structural design and future following researches.

• 소성∙가공
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• 제13권1호
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• pp.90-101
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• 2004

An inverse mosaic method has been proposed to generate an initial blank shape from the final product shape. Differently from the geometric mapping method, the method can handle triangular patches. However, the generated blank shape is strongly dependent on the order of determination of nodes. In order to compensate the dependency error smoothing technique has been also developed. Although the accuracy has been improved greatly compared with the geometrical mapping method, the method has limitation, due to the no incorporation of plasticity theory. Even though the accuracy of the radius vector method is already proved. the method requires initial guess to start the method. In order to compromise the limitation of the present method and the radius vector method, the method has been connected to the radius vector method. The efficiency of the present optimal blank design method has been verified with some chosen examples.

• Structural Engineering and Mechanics
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• 제6권2호
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• pp.173-183
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• 1998

In the shape design of flexible structures, it is useful to predict the initial shape from the desirable large deformed shapes under some loading conditions. In this paper, we present a numerical procedure of an initial shape determination problem for hyperelastic materials which enables us to calculate an initial shape corresponding to the prescribed deformed shape and boundary condition. The present procedure is based on an Arbitrary Lagrangian-Eulerian (ALE) finite element method for hyperelasticity, in which arbitrary change of shapes in both the initial and deformed states can be treated by considering the variation of geometric mappings in the equilibrium equation. Then the determination problem of the initial shape can be formulated as a nonlinear problem to solve the unknown initial shape for the specified deformed shape that satisfies the equilibrium equation. The present approach can be implemented easily to the finite element method by employing the isoparametric hypothesis. Some basic numerical results are also given to characterize the present procedure.

• 대한전자공학회논문지SP
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• 제39권4호
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• pp.462-469
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• 2002

벡터 부호책 설계에 사용되는 기존 K-means 알고리즘은 모든 학습반복에서 고정된 가중치를 적용하는데 반해 제안된 방법은 학습반복마다 가변되는 가중치를 적용한다. 초기 학습반복에서는 새로운 부호벡터를 얻기 위해 수렴영역을 벗어나는 2 이상의 가중치를 사용하고, 이 값이 클수록 가변 가중치를 적용하는 학습반복을 줄임으로써 우수한 부호책을 설계할 수 있다. 초기 부호책 설계에 사용되는 미세분할 방법을 개선하기 위하여 소속 학습벡터와 대표벡터간의 오차를 줄이는 방법을 사용한다. 즉 자승오차가 최대인 대표벡터를 제외시키고 최소인 대표벡터를 미세분할함으로써 초기 부호벡터로 대체될 보다 적절한 대표벡터를 얻을 수 있다.

• 한국시뮬레이션학회논문지
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• 제12권3호
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• pp.41-53
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• 2003

The major components of an engine are engine block (or cylinder block), cylinder head, crank shaft, connecting rod and cam shaft. Thus the engine shop usually consists of six sub-lines, five machining lines and one assembly line. Flow line is the typical concept of layout for machining these parts, especially for engine block. In order to design an engine block machining line, several factors should be considered such as yearly production target, working hours, machines, tools, material handling equipments and so on. If the designers of manufacturing line were unaware of some factors those would be influenced on the system performance, it would make greater problems in the phase of mass production. Therefore the initial design of engine block machining line should be verified carefully. Simulation is the most powerful tool for analyzing the initial layout. This paper introduces the major factors those should be considered for designing the machining line and their effects on the system performance. 3D simulation models are developed with QUEST. Using the simulation model developed the initial layout is analyzed, and we suggest some ideas for improvement.