• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.264-268
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• 1987

This paper is concerned on kinematic analysis and simulation of an automatic feeding mechanism subjected by the motion of a curvilinear inverse can. The curvilinear cam is rotated by positioning a translating roller and the automatic feeding mechanism is moved to the sliding position by the motion of a campin fixed on the curvilinear cam. The curvilinear cam consists of two arcs of circles and two straight lines. The modular approach is used for the kinematic analysis of the feeding mechanism. As the first part of the paper for the motion simulation of the cam-feeding system, this paper discusses the algorithm to simulate the motion of the cam-feeding mechanism. The second part of the paper presents the state-of-art for the graphics-oriented CAD technique,

• Advances in Computational Design
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• 제6권1호
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• pp.15-30
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• 2021

With improvement in innovative manufacturing technologies, it became possible to fabricate any complex shaped structural design for practical applications. This allows for the fabrication of curvilinearly stiffened pressure vessels and pipes. Compared to straight stiffeners, curvilinear stiffeners have shown to have better structural performance and weight savings under certain loading conditions. In this paper, an optimization framework for designing curvilinearly stiffened composite pressure vessels and pipes is presented. NURBS are utilized to define curvilinear stiffeners over the surface of the pipe. An integrated tool using Python, Rhinoceros 3D, MSC.PATRAN and MSC.NASTRAN is implemented for performing the optimization. Rhinoceros 3D is used for creating the geometry, which later is exported to MSC.PATRAN for finite element model generation. Finally, MSC.NASTRAN is used for structural analysis. A Bi-Level Programming (BLP) optimization technique, consisting of Particle Swarm Optimization (PSO) and Gradient-Based Optimization (GBO), is used to find optimal locations of stiffeners, geometric dimensions for stiffener cross-sections and layer thickness for the composite skin. A cylindrical pipe stiffened by orthogonal and curvilinear stiffeners under torsional and bending load cases is studied. It is seen that curvilinear stiffeners can lead to a potential 10.8% weight saving in the structure as compared to the case of using straight stiffeners.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 추계학술발표대회 논문집
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• pp.242-245
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• 1999

In aerospace industry improvement of structural performance of flight structure without increasing weight has great advantage. In this study, an innovative design method to increase the buckling load and tension failure load at the same time without increasing the weight was investigated by using the curvilinear fiber format in composite plates with central hole. It was investigated how much gain can be obtained with curvilinear fiber format for the plates with different hole size and different stacking sequence.

• 대한조선학회논문집
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• 제58권3호
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• pp.191-197
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• 2021

This study addresses autonomous ship collision avoidance in narrow channels using curvilinear coordinates. Navigation in narrow channels or fairways is known to be much more difficult and challenging compared with navigation in the open sea. It is not straightforward to apply the existing collision avoidance framework designed for use in the open sea to collision avoidance in narrow channels due to the complexity of the problem. In this study, to generalize the autonomous navigation procedure for collision avoidance in narrow channels, we introduce a curvilinear coordinate system for collision-free path planning using a parametric curve, B-spline. To demonstrate the feasibility of the proposed algorithm, ship traffic simulations were performed and the results are presented.

• 조형예술학연구
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• 제6권
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• pp.5-32
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• 2004

Kim Hwan-ki's New York Period works consistently present, as the central signifier, a curvilinear paradigm which has been derived from his creative consciousness. The purpose of this study is to bring to light what exists behind curvilinear paradigms; a fusion of history and society with the artist's individual consciousness as a fused aspect of history and society. To make this aspect suitably understood, this study focuses on curvilinear signifier which are analyzed and considered objectively. The results of which are as follows: It is a representative example of transforming a curved line which is the modern quotation of traditional Korean art, most directly works done in porcelain. He takes the aesthetic consciousness of Korean art as the power of his works and takes aim at the collective consciousness of all races. Looking through the background of his times, his artistic subject was to find the ethic characteristics of our excellent tradition and highlight them in his art. To him, art is not about making the most of a skill but instead about allowing one's inner spirit sing it's own song. This thought is conveyed in curvilinear signifier of his works. Therefore this study has asserted that Kim Hwan-ki's curvilinear signifier in his New York Period works has strong ties to the cultural vein of Korean history and society at it's base as well as simply in his individual level. This assertion is not to set form in a superior position as a Formalist but to show form as having the will to deal with the significance of an artist's mode by interpreting the experience of the interpreter.

• 경영과정보연구
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• 제34권3호
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• pp.101-123
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• 2015

외부 환경의 불확실성이 점점 더 높아지는 가운데 조직의 경쟁우위를 달성하기 위한 방안으로 우수한 인적자원의 확보 및 보유가 점차 중요시되고 있다. 특히, 동료 직원들에 비해 몇 배나 높은 탁월한 성과를 창출할 수 있는 '스타 인재'는 지식과 정보가 중시되는 지식기반산업에서 점차 그 중요성이 강조되고 있어 이에 관련된 학계와 산업계의 관심이 증대되고 있다. 하지만 이처럼 스타 인재에 대한 관심이 증가하고 있음에도 불구하고 스타 인재의 보유가 조직성과에 미치는 영향을 실증적으로 분석한 선행연구는 부족한 편이다. 특히 스타 인재의 보유가 조직 내외부에 미치는 긍정적 부정적 영향력을 고려할 때, 조직 내 스타 인재의 비율(ratio of star employee)과 조직성과의 관계는 단순 선형 관계(simple linear relationship)의 가능성 뿐 아니라 비선형의 곡선형 관계(curvilinear relationship)가 존재할 가능성도 가지고 있다. 이에 본 연구에서는 스타 인재에 관한 선행 연구를 토대로, 스타 인재의 비율이 증가함에 따라 한계효과가 증가하는 체증관계(U자형 곡선)와 한계효과가 감소하는 체감관계(역U자형 곡선)의 두 가지 대립가설을 설정한 후 국내 34개 상장증권사의 2008~2013년 134개 관측수를 대상으로 실증분석을 진행하였다. 국내 경제전문지가 선정한 '베스트 애널리스트'(스타 인재)의 비율이 증권사의 재무성과에 미치는 영향을 불균형 패널모형으로 검증한 결과, 스타 인재의 비율이 증가할수록 조직성과는 증가하지만, 그 한계효과는 점차 감소하는 체감형 비선형 관계가 검증되었다. 이러한 연구결과는 지식기반 산업에서도 스타 인재를 활용하는 것이 중요함을 시사함과 동시에, 스타 인재에 대한 과도한 의존은 경계할 필요성이 있음을 시사한다.

• Structural Engineering and Mechanics
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• 제61권2호
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• pp.255-266
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• 2017

In this study, self-supporting roofing elements especially convenient for large-span structures such as stadium, airport terminal, mall, coliseum, etc. were examined with respect to critical buckling load. These elements were assumed as laminated composite plates and, variation of free-edge forms, cutout types and lamination configurations were used as design parameters. Based on the architectural feature and structural requirements, the effects of curvilinear free-edge form on critical buckling load were focused on in this research. Within this scope, 14 types of lamination configuration were specified according to various orientation angle, number and thickness of plies with a constant value of total plate thickness. Besides that, 6 different types of cutout and 3 different free-edge forms were determined. By combining all these parameters 294 different critical buckling load analyses were performed by using ANSYS Mechanical software based on finite element method. Effects of those parameters on critical buckling load were evaluated referring to the obtained results. According to the results presented here, it may be concluded that lamination conditions have more significant influence on the critical buckling load values than the other parameters. On the other hand, it is perceived that curvilinear free-edge forms explicitly undergo changings depending on lamination conditions. For future work, existence of delamination might be considered and progression of the defect could be investigated by using non-linear analysis.

• Composites Research
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• 제12권6호
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• pp.31-42
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• 1999

항공우주산업에서 무게를 증가시키지 않고 비행구조물의 구조적 성능을 증가시키는 것은 굉장한 잇점을 갖는다. 본 연구에서는 복합재료 평판의 무게를 증가시키지 않고 좌굴하중과 인장 파단하중을 동시에 증가시키는 혁신적인 설계 방법에 대해서 연구하였다. 원공이 있는 복합재료 적층판에서 곡선 섬유층과 직선 섬유층을 조합하여 적층판을 구성할 때 좌굴하중과 인장파단 하중이 동시에 증가되는 현상에 대하여 유한요소 해석을 사용하여 알아보았다. 원공의 크기와 적층 순서를 달리하면서 곡선섬유를 이용한 효과가 얼마나 되는지 알아보았다. 또한, 각각의 경우에 대해서 파단이 어떻게 일어나는가도 관찰하였다. 곡선섬유 평판을 제작하기 위해서는 연속적이고 부드럽게 변하는 fiber path가 필요하다. 여기서는 유한요소로 구한 섬유 방향을 사용하여 제작이 가능한 부드럽게 이어지는 fiber path를 구하는 간단한 방안을 제시하였다.

• KEPCO Journal on Electric Power and Energy
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• 제2권4호
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• pp.627-630
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• 2016

Recently, the size of wind farms is becoming larger, and the integration of high wind generation resources into power gird is becoming more important. Due to intermittency of wind generating resources, it is an essential to predict power outputs. In this paper, we introduce the basic concept of curvilinear regression, which is one of the method of wind power prediction. The empirical data, wind farm power output in Jeju Island, is considered to verify the proposed prediction model.

• 대한수학회보
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• 제55권3호
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• pp.881-898
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• 2018

This article deals with implementation of a high-order finite difference scheme for numerical solution of the incompressible Navier-Stokes equations on curvilinear grids. The numerical scheme is based on pseudo-compressibility approach. A fifth-order upwind compact scheme is used to approximate the inviscid fluxes while the discretization of metric and viscous terms is accomplished using sixth-order central compact scheme. An implicit Euler method is used for discretization of the pseudo-time derivative to obtain the steady-state solution. The resulting block tridiagonal matrix system is solved by approximate factorization based alternating direction implicit scheme (AF-ADI) which consists of an alternate sweep in each direction for every pseudo-time step. The convergence and efficiency of the method are evaluated by solving some 2D benchmark problems. Finally, computed results are compared with numerical results in the literature and a good agreement is observed.