• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.96-99
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• 1996

본 연구는 CAD/CAM에서 3차원 물체를 표현하는 기법중 하나인 Solid Modeling을 구성하는 데이터 구조를 객체지향화 함으로써 보다 효율적이고 유연한 설계개발환경을 제공하고자 한다. 이를 위해서 가장 일반적으로 Solid Modeling을 표현하는 데이터 구조인 기존의 Half-Edge Data Structure를 기본모델로 하여 점(Vortex), 선(Edge), 면(Face), 입체(Solid)를 객체 Class로 하고 Euler Operator를 Method로 하는 객체지향 반모서리 데이터 구조(Object Oriented Half-Edge Data Structure)를 개발하였다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.33-34
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• 2001

지금까지 이러한 선망 어구의 조업시 형상에 관해 많은 연구 결과들이 있다. 그러나 이들 대부분이 해상실험 또는 모형실험으로서 실험자체의 어려움과 번거러움 등으로 다양한 실험이 불가능하다. 이러한 실험의 단점을 보완할 수 있는 것이 시뮬레이션에 의한 연구이다. 하지만, 선망어구는 매우 대형의 어구 시스템이며 대부분 그물이라는 유연한 물체에 의해 구성되어있어 외력에 대해 그 형상이 비선형적이므로 그 형상과 운동을 정의하기가 어렵다. (중략)

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.1
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• pp.31-40
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• 2021

Modern aircraft are high-performance and lightweight. Thus, the characteristics of the flexible structure appear and affect flight performance or limit it. These flexible characteristics need to be analyzed from the early stages of aircraft design. To this end, a program to analyze the dynamic and static behavior of flexible aircraft has been developed and the results are presented. Based on the multi-body dynamics simulation technique, rigid flight mechanics, structural vibrating behavior, and unsteady aerodynamics have been developed and integrated. Lastly, the level flight and the turn flight of the flexible characteristic aircraft have been analyzed using this integrated simulation program.

• Journal of the Korea Computer Graphics Society
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• v.5 no.1
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• pp.27-33
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• 1999

In this paper, we propose an efficient technique for the animation of flexible thin objects. Mass-spring model was employed to represent the flexible objects. Till now, many techniques have used the mass-spring model to generate plausible animation of soft objects. A straight-forward approach to the animation with mass-spring model is explicit Euler method, but the explicit Euler method has serious disadvantage that it suffers from 'instability problem'. The implicit integration method is a possible solution to overcome the instability problem. However, the most critical flaw of the implicit method is that it involves a large linear system. This paper presents a fast animation technique for mass-spring model with approximated implicit method. The proposed technique stably updates the state of n mass-points in O(n) time when the number of total springs are O(n). We also consider the interaction of the flexible object and air in order to generate plausible results.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.22-31
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• 1996

An efficient calculation method of pressure acting on a bluff body is developed. The method is applied to assess the containment capability of an oil fence, considering skirt deformation in current. The pressure on the frontal side of the oil fence is determined by analyzing the potential flow, substituting the wake region as a rigid body which has its boundary at the closed separation streamlines. The pressure at the downstream side of the fence, the so called base pressure, is obtained from the existing experimental results. To verify the calculation method, pressure drag of some bluff bodies in an infinite-fluid medium is calculated, which shows good agreement with the experimental results. The deformed shape of the oil fence is obtained by solving, iteratively, the coupled equations governing the flow field and the deformation of the oil fence, respectively. The deformed shape and the decrease of draft of oil fences with different ballast mass in various current conditions are investigated.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.1
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• pp.56-65
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• 2006

Recently the study on service robots has been proliferated in many fields, and there are active developments for indoor services such as supporting for elderly people. It is important for robot to recognize objects and situations appropriately for effective and accurate service. Conventional object recognition methods have been based on the pre-defined geometric models, but they have limitations in indoor environments with uncertain situation such as the target objects are occluded by other ones. In this paper we propose a Bayesian network model to reason the probability of target objects for effective detection. We model the relationships between objects by activities, which are applied to non-static environments more flexibly. Overall structure is constructed by combining common-cause structures which are the units making relationship between objects, and it makes design process more efficient. We test the performance of two Bayesian networks for verifying the proposed Bayesian network model through experiments, resulting in accuracy of $86.5\%$ and $89.6\%$ respectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.2
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• pp.175-181
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• 2010

This paper presents the dynamic analysis method for estimating the performance of flat-type blades in wiper systems. The blade has nonlinear characteristics since the rubber is a hyper-elastic material. Thus, modal coordinate and absolute nodal coordinate formulations were used to describe the dynamic characteristic of the blade. The blade was structurally analyzed to find the bending characteristics of the cross section of the blade. According to the analysis results, the blade section is divided into three deformation bodies: rigid, small, and large. For the small deformation body, the modal coordinate formulation is used, while the absolute nodal coordinate formulation is used for the large deformation body. To verify the dynamic analysis result, an experiment was performed. The simulation and experiment results were compared to verify the flexible multi-body dynamic model.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05c
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• pp.170-175
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• 2002

영상분할이나 연결요소 추출 등에 의해 구해진 물체 영역의 경계 부분에 잔가지 모양으로 나타나는 잡영가지는 물체의 형상 특징 연산 및 인식 과정에서 오류를 일으키는 원인이 되므로 효과적으로 제거할 수 있는 방법이 필요하다. 기존의 연구에서는 한 픽셀 두께의 잡영가지만을 제거할 수 있는 방법이 제안되었다. 본 연구에서는 부분적으로 두 픽셀 이상이 뭉쳐져 둥그스름한 덩어리(blob, 블럽)를 형성하고 있는 잡영가지도 4-8-방향 윤곽선 추적에 의해 제거할 수 있는 방법을 제안한다. 먼저 잔가지를 구성하고 있는 픽셀과 물체 영역을 구성하는 픽셀을 개략적으로 분리한 후, 윤곽선 추적물 하면서 사용자가 정의한 크기보다 작은 블럽을 포항한 잔가지를 추출해낸다. 이어서, 이러한 잔가지를 사용자가 정의한 잡영가지의 크기와 비교하여 최종적으로 제거할 수 있도록 한다. 이와 같이 사용자 입력 변수에 따라 잡영가지에 대한 개념을 보다 확장하여 자유롭게 정의할 수 있도록 명시화 함으로써, 영상의 특성에 따라 보다 유연하게 잡영가지를 정의하여 제거할 수 있도록 하였다.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.193.1-193.1
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• 2005

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.5-9
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• 1987

In this study, three insertion techniques vibration method, tactile sensor-assisted method and vision assisted method are developed for the insertion of electric contacts into connectors. In order to prove their Performances, a series of experiments were conducted for various shapes of el-ectric contacts. From the experimental results, three insertion methods are compared and their merits are discussed in detail.