• Journal of the Society of Naval Architects of Korea
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• v.32 no.3
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• pp.29-36
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• 1995

This paper presents a variation method of the parent ship using sectional area curve & the definition of NURBS curve. That is, global variation of the hull form is made systematically by the geometrical property of sectional area curve, and Local variation of the hull form is executed by the definition of NURBS curve. Then the designer may determine New hull form considering New section area curve, design condition, etc.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.317-322
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• 2004

Productivity of shoe industry in Korea is still more excellent then that of China or Vietnam, But manufacturing technology and productive facility are underdevelopment in comparison advanced country. CAD/CAM system development, one of the most important technology, is totally nonexistent. specially, the automatic generation function and the grading function in shoe sole modeling are dependent of the foreign software. The CAD/CAM software only for shoe modeling is very expensive, so that it is going to weaken shoe industry of Korea. Therefore, We developed 3D gauge curve generation method using 2D NURBS curve in shoe sole modeling.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.1
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• pp.1-8
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• 1995

This paper presents possibilities of a numerical hull form representation in the form of curve designs, which require a variety of form variations. The numerical representation method of the hull form is developed using NURBS curve with sufficient continuity and local variation.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.40-44
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• 2001

선형개발에 대한 연구는 주로 대형선박을 기준으로 Bezier, B-spline 그리고 NURBS와 같은 합성곡선생성기법을 이용하여 일반 곡선기법으로는 표현하기 힘든 구상선수나 굴곡이 심한 선미 등을 표현하고 검증하는 것으로 이루어지고 있다. 하지만, 전체 선박의 70%를 차지하고 있는 중소형 어선의 선형에 대한 연구나 기술적인 보고는 상대적으로 미흡한 실정이다. 본 연구에서는 기존의 라운드타입에서 챠인 및 신챠인타입으로 변화해 가는 중소형 어선의 선형을 NURBS기법을 이용하여 표현하고, 전산화하는 프로그램을 개발하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.63-66
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• 2009

본 논문에서는 트림영역이 있는 NURBS 평면을 등기하 해석할 수 있는 방법을 제시한다. 기존 등기하 해석법으로 트림 NURBS 곡면을 해석하기 위해서는 해석 도메인이 여러 개의 사각형 패치로 분할되어있어야 한다. 그러나 본 연구에서 제안한 방법은 CAD에서 제공하는 트림곡선의 정보를 해석에 직접 사용할 수 있기 때문에 CAD 모델을 별도로 재구성해야하는 번거로움이 없다. NURBS 곡선 투영법을 이용하여 트림되는 요소를 찾고, 트림된 요소는 쿼드트리 분할법과 NEFEM에서 사용된 적분방법을 동시에 고려하면 어떤 경우의 트림 요소라도 적분이 가능하다. 다양한 수치 예제를 통하여 제안한 해석 방법을 검증하고, 기존의 등기하해석법으로 해석하기 어려운 다수의 트림영역이 존재하는 NURBS 평면을 해석하여 본 방법의 유용성을 검토한다.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.2
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• pp.1-9
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• 1995

This paper suggests a numerical method that creates and varies hull form geometry of underwater vehicle. That is, it induces the cylindrical underwater vehicle from principal dimensions-total length, the length of parallel middle body, the coefficient defining entrance & run parts etc.-and represents using NURBS curve. Also, each section of hull form is varied by user interface and Sectional Area Curve is generated.

• Journal of KIISE:Computer Systems and Theory
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• v.34 no.1
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• pp.38-48
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• 2007

In this paper, we propose an image-based method for modeling 3D objects with curved surfaces based on the NURBS (Non-Uniform Rational B-Splines) representation. Starting from a few calibrated images, the user specifies the corresponding curves by means of an interactive user interface. Then, the 3D curves are reconstructed using stereo reconstruction. In order to fit the curves easily using the interactive user interface, NURBS curves and surfaces are employed. The proposed surface modeling techniques include surface building methods such as bilinear surfaces, ruled surfaces, generalized cylinders, and surfaces of revolution. In addition to these methods, we also propose various advanced surface modeling techniques, including skinned surfaces, swept surfaces, and boundary patches. Based on these surface modeling techniques, it is possible to build various types of 3D shape models with textured curved surfaces without much effort. Also, it is possible to reconstruct more realistic surfaces by using proposed view-dependent texture acquisition algorithm. Constructed 3D shape model with curves and curved surfaces can be exported in VRML format, making it possible to be used in different 3D graphics softwares.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.698-706
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• 2005

Finish machining of a curved surface is often carried out by an NC system with curve interpolation in the field. This NURBS interpolation adopts a feedrate optimizing strategy based on both the geometrical information and dynamic properties. In case of a finish cut using a ball-end mill, the curve interpolator needs to take the machining process into account for more improved surface, while reducing the polishing time. In this study, the effect of low machinability at the bottom of a tool on surface roughness is also considered. A particular curve interpolation algorithm is proposed fur generating feedrate commands which are able to control the roughness of a curved surface. The simulation of the machined surface by the proposed algorithm was carried out, and experimental results are presented.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.405-410
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• 2001

In this paper, a new parametric curve interpolator is proposed based on a 3D(3-dimensional) NURBS curve. A free curve is generally divided into small linear segments or circular arcs in CNC machining. The method has caused to a command error, the limitation of machining speed, and the irregular machining surface. The proposed real-time 3D NURBS interpolator continuously generates a linear segment within the range of allowable acceleration/deceleration in the motion controller. Therefore, the algorithm calculates the curvature and the remained distance of a command curve for the smoothing machining. It is expected to attaining high speed and high precision machining in CNC Machine Tool.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.2
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• pp.106-113
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• 2018

The Intense acoustic wave generated by the jet flame at the lift-off causes the vehicle to vibrate in the form of acoustic loads. The DSM-II(Distributing Source Method-II), which is a representative empirical acoustic loads prediction method, is a method of distributing a noise source along a jet flame axis and has advantages in calculation cost and accuracy. However, due to the limitation of the distributing method, there is a limit to accurately reflect the various launch pad configurations. In this study, acoustic loads prediction method which can freely distribute noise sources is studied. by introducing NURBS(Non-Uniform Rational B-Spline) modeling into empirical prediction method. For the verification of the newly introduced analytical technique of the NURBS, the acoustic loads prediction for the Epsilon rocket's low-noise launch pad shape was performed and the results of the analysis were compared with the existing prediction methods and experimental results.