• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.655-666
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• 2014

Recently, as the appearance and exterior design of the construction structure are highlighted, the irregularly shaped structures are increasing in a construction facility. Many softwares provide a quantity take-off function of 3D object under BIM environment, however, they are focused on the limited function based on the solid modeling method. Because the vast geometric information of the curved surface is difficult to extract in the 3D objects that consist of major changes in vertical section shape as the irregularly shaped structures, it is difficult to express a 3D object as a solid model. On the other hand, the irregularly shaped structures can be expressed in relatively free in the surface model because the surface model consists of points, lines and surfaces. Accordingly, the surface modeling method is suitable for the modeling of large irregularly shaped structures. This study suggests a quantity take-off algorithm for the irregularly shaped structures using the surface modeling approach that is beneficial in the design work of structures. Some case projects are used for verifying the accuracy of the proposed method.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1527-1543
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• 2021

In this paper, we explore the applicability and utility of a technology that generating clustered solid building models based on point cloud automatically by applying it to various data. In order to improve the quality of the model of insufficient quality due to the limitations of the automatic building modeling technology, we develop the building shape modification and texture correction technology and confirmed the resultsthrough experiments. In order to explore the applicability of automatic building model generation technology, we experimented using point cloud and LiDAR (Light Detection and Ranging) data generated based on UAV, and applied building shape modification and texture correction technology to the automatically generated building model. Then, experiments were performed to improve the quality of the model. Through this, the applicability of the point cloud data-based automatic clustered solid building model generation technology and the effectiveness of the model quality improvement technology were confirmed. Compared to the existing building modeling technology, our technology greatly reduces costs such as manpower and time and is expected to have strengths in the management of modeling results.

• Journal of Ocean Engineering and Technology
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• v.9 no.2
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• pp.83-88
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• 1995

In this paper, the solid modeller suitable for PC was developed for Top-down 3-D representation and analysis of fixed offshore structures. Also solid modelling and hidden line removal were conducted in order to visualize the offshore structures based on the scan line z-buffer algorithm.

• Journal of the KSME
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• v.31 no.1
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• pp.34-42
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• 1991

복잡한 형상의 서지 탱크를 CAEDS의 GEOMOD를 이용하여 내부의 리보까지 포함한 용기를 모델링하였으며, 설계 부피를 검사하고 GEOMOD와 GFEM 사이의 직접 데이터 교환을 통하여 구조 해석에 필요한 유한요소를 만들었다. 유한요소법에 최적화 이론을 적용하여 서지탱크의 두께 변화에 따른 응력의 설계 민감도를 구하였으며, 민감도를 근거로 보강 위치 및 국부적인 용기의 두께를 결정하였다. 유한요소법 프로그램(IFES, GFEM)과 솔리드 모델러(GEOMOD), 그리고 최적화 기법(IFES-Optimization)을 모두 통합하여, 최적 설계를 수행함으로써 반복되는 실험에 의한 시간과 경비를 줄임과 동시에 신뢰성 있는 설계방법 및 방향을 제시하였다.

• IE interfaces
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• v.8 no.3
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• pp.141-153
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• 1995

기존의 솔리드 모델링 시스템은 형상 표현에 있어서의 제약성과 통합 시스템으로서의 폐쇄성으로 인하여 응용 범위에 제약이 따른다. 이러한 약점을 극복하고자 하는 노력의 일환으로서, 최근에 등장한 것이 비다양체 모델을 지원하는 CAD 시스템 커널이다. 본 논문에서는 이러한 비다양체 모델을 지원할 수 있는 모델링 커널 시스템 개발의 기초가 되는 비다양체 자료구조와 이것을 바탕으로 한 오일러 공식 및 오일러 작업에 대해 소개한다. 그리고 이러한 오일러 작업을 실제로 구현하여 모델링 작업을 수행해 봄으로써, 본 논문에서는 제안된 비다양체 자료구조와 오일러 작업의 유용성을 보인다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.10
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• pp.2446-2456
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• 1993

By virtue of progress of computer science, CAD/CAM technology has been developed greatly in each area. But the problems in the integration of CAD/CAM are not yet solved completely. The reason is that the exchange of data between CAD and CAM is difficult because the domains of design and manufacturing are different in nature. To solve this problem, a feature based modeller is developed in this study, which makes it possible to communicate between design and manufacturing through features. The modeller has feature, the concept of semi-bounded plane is introduced, and implemented as a B-rep sheet model using half-edge data structure. The features are then created on a part by local modification of the boundary on a part based on feature template information. This approach generalizes the modelling of features in a geometry model.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.181-186
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• 2007

UBM (Under Bump Metallurgy) of flip chip assemblies consists of several layers such as the solder wetting, the diffusion barrier, and the adhesion layers. In addition, IMC layers are formed between the solder wetting layers (e.g. Cu, Ni) and the solder. The primary failure mechanism of the solder joints in flip chips is widely known as the fatigue failure caused by thermal fatigues or electromigration damages. Sometimes, the premature brittle failure occurs in the IMC layers. However, these phenomena have thus far been viewed from only experimental investigations. In this sense, this paper presents a method for solid modeling of IMC layers in flip chip assemblies, thus providing a pre-processing tool for finite element analysis to simulate the IMC failure mechanism. The proposed modeling method is CSG-based and can also be applied to the modeling of UBM structure in flip chip assemblies. This is done by performing Boolean operations according to the actual sequences of fabrication processes

• Proceedings of the KAIS Fall Conference
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• 2001.11a
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• pp.135-138
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• 2001

The design and manufacture of injection molded Sear with desired Properties is a costly process dominated by empiricism including the interactive modification of prototype toolings. In this paper, an interactive computer-based design system for injection molded gear is developed in order to realize the concept of rational design for the productivity and quality of mold making of a small plastic gear. The knowledge-based synthesis system being developed in this paper combines a rule-based expert system with analytical process simulation programs in a synergistical manner. Quick and logical evaluations on the design of injection molded gear can be made on the scientific analysis and the accumulated experts' knowledge.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.5
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• pp.1503-1511
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• 1991

본 연구에서는 곡면을 포함할 수도 있는 얇은 물체를 모델링하기 위해 새로운 기법을 도입했는데, 그 기본 개념은 다음과 같다. Fig.(a)에서와 같이 먼저 사용자 는 박판으로 불리는 두께가 없는 얇은 판을 여러장 가지고 이들을 접거나, 오려내거나, 붙이는 등의 작업을 통해서 원하는 형상으로 모델링한다.각각의 박판의 형상의 입 력은 거의 모두 2차원 좌표계에서 이루어지기 때문에, 사용자는 마치 철판위에 선을 긋는 것과 같이 쉽게 박판의 형상을 입력할 수 있다. 또한 박판에서 임의의 부분을 오려내거나 임의의 박판을 붙이는 등의 작업을 통해서 원하는 형상으로 모델링한다. 각각의 박판의 형상의 입력은 거의 모두 2차원 좌표계에서 이루어지기 때문에, 사용자 는 마치 철판위에 선을 긋는 것과 같이 쉽게 박판의 형상을 입력할 수 있다. 또한 박판에서 임의의 부분을 오려내거나 임의의 박판을 붙이는 등의 작업이 기존의 시스템 에서와는 달리 복잡한 입력이나, 수행과정을 거치지 않기 때문에, 보다 편리한 모델링 을 할 수 있다. 또한 곡면으로 된 박판 형상의 경우는 해당되는 모서리들을 곡선으 로 바꿈으로써 모델링 되도록 하였다. 박판의 모델링이 끝나면, 입력된 박판에 일정 한 두께를 부여하여 Fig.2(b)에서와 같이 부피를 갖는 입체(솔리드)로 변환하게 되는 데 이 작업은 Stroud에 의한 것과 같이 시스템에서 자동으로 이루어진다.

• Journal of Korean Society of Steel Construction
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• v.25 no.3
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• pp.307-320
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• 2013

This paper proposes a new hybrid support structure by the driven piles which removes disadvantages of the existing type of support structure for offshore wind turbines. The hybrid type of support structure is combined with concrete cone and steel shaft, and is supported not only by gravity type foundations but also by driven piles. For three dimensional analysis of the huge and thick concrete structure, a solid-shell element that is capable of exact modeling and node interpolations of stresses is developed. By applying wave theory of stream function and solid-shell element in XSEA simulation software for fixed offshore wind turbines, a quasi-static analysis and natural frequency analysis of proposed support structure are performed with the environmental condition on Southwest Coast in Korea. In the result, lateral displacement is not exceed allowable displacement and a superiority of dynamic behavior of new hybrid support structure is validated by natural frequency analysis. Consequently, the hybrid support structure presented in this study has a structural stability enough to be applied on real-site condition in Korea. The optimized structures based on the preliminary design concept resulted in an efficient structure, which reasonably reduces fabrication costs.