• 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.

• 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.

• 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 the Society of Naval Architects of Korea
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• v.34 no.3
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• pp.96-103
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• 1997

This paper presents a mathematical method that represents efficiently high-speed coastal fishing vessel. That is, it represents the numerical hull by using irrational function and hull form characteristic curves, which define a hull form under design conditions. Then it suggests a process that hull form characteristic curves are represented with NURBS and hull form is varied.

• Archives of design research
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• v.13
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• pp.83-91
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• 1996

In this paper, proposed through the development process of a VCR the process of making exact three-dimensional modeling data using the Alias-one of the popular workstation in product design development process. At first, the features of the NURBS curve which is the basic curve in the modeling of Alias system and the methods of building surface are reviewed. The methods of rendering, lighting and textures are reviewed for application of realistic image presentation after building basic surfaces. The synthetic application methode of these factors necessary for the product design modeling is presented through the development process of a VCR.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.934-938
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• 2000

This paper presents a laser cutting of 2D image. 2D image in pixel graphic format is converted into vector graphic image by image processing. Bitmap graphics are made easily, but can not being used in application works for geometry transition. The Sobel's Edge detection method is used to find boundary points on 2D image. The points are fitted into curves with sampling and filtering. Sampling can provide efficient computation and filtering reconstuct features in image. The NC code is generated on MURBS curve of the points. Also, the offset of contour and cutting conditions are considered.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.333-340
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• 2018

Recently, free-form buildings have been designed with complex shapes due to digitization of the construction industry. Exterior and interior components of free-form buildings have free cross sections and curved shapes. Therefore, structural members with curvature are frequently seen. In the modeling and stability evaluation of these structures, commercial programs using classical finite element analysis are not able to perform rapid shape modeling, resulting in a decrease in productivity. Therefore, in this study, pre- and post-processing modules were developed using a prior study to rapidly model the surface of a free-form building and to automatically generate frame structures that make up the cladding. The developed modules use a subdivision algorithm with spline curves. This algorithm is used to automatically generate analytical elements from the configuration information of NURBS curves. In addition, the deformation after analysis can be viewed more realistically. The modules can quickly construct complex curved surfaces. An analysis model of the frame structure was also automatically generated. Therefore, the modules could contribute to the productivity improvement of free-form building design.

• Korean Journal of Computational Design and Engineering
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• v.15 no.4
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• pp.253-260
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• 2010

This paper presents algorithms for computing offsets of freeform curves. The approach first divides the original curve into several segments at the inflexion points. Based on the obtained new control polygon and its offsets, quadratic trigonometric splines are constructed to approximate the offset curves. Finally, the shape parameter value of trigonometric spline is determined to satisfy the required tolerance. The degree of the output curve is two, independent of the original curve's degree. Because of the great controllability, the proposed method can generate a completely overestimating offset curve by adjusting the value of the shape parameter, which guarantees no overcutting in NC machining. Furthermore, it also produces the lowest number of control points compared with other works.

• Journal of Navigation and Port Research
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• v.30 no.10 s.116
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• pp.869-875
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• 2006

This paper presents the method for developing an optimum hull form with minimum wave resistance using SQP(sequential quadratic programming) as an optimization technique. The wave resistance is evaluated by a Rankine source panel method with non-linear free surface conditions and the ITTC 1957 friction line is used to predict the frictional resistance coefficient. The geometry of the hull surface is represented and modified using NURBS(Non-Uniform Rational B-Spline) surface patches. To verity the validity of the developed program the numerical calculations for Wigley hull and Series 60( $C_B=0.6$) hull have been performed and the results obtained by the numerical calculations have been compared with the original hulls.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.47-53
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• 2005

This paper presents the method for developing an optimum hull form with minimum wave resistance using SQP(sequential quadratic programming) as an optimization technique. The wave resistance is evaluated by a Rankine source panel method with non-linear free surface conditions and the ITTC 1957 friction line is used to predict the frictional resistance coefficient. The geometry of the hull surface is represented and modified using NURBS(Non-Uniform Rational B-Spline) surface patches. To verity the validity of the developed program the numerical calculations for Wigley hull and Series 60(C${_B}$=0.6) hull had been performed and the results obtained after the numerical calculations had been compared with the original hulls.