• Journal of Computational Design and Engineering
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• 제2권3호
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• pp.129-136
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• 2015

This paper proposes a novel method for shape design of a Bezier surface with given boundary curves. The surface is defined as the minimizer of an extended membrane functional or an extended thin plate functional under the guidance of a specified normal field together with an initial prescribed surface. For given boundary curves and the guiding normal field, the free coefficients of a Bezier surface are obtained by solving a linear system. Unlike previous PDE based surface modeling techniques which construct surfaces just from boundaries, our proposed method can be used to generate smooth and fair surfaces that even follow a specified normal field. Several interesting examples are given to demonstrate the applications of the proposed method in geometric modeling.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.378-386
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• 1999

The integrated system for the structural analysis of space frame is made up 4 modules ; pre-process module, structural analysis module, optimum member design module and post-process module. Re-process module of these 4 modules involves data input module and structure modeling module. This study is to develope an efficient modeling program as a basic for development of pre-process module. This modeling program generates geometric information of space frame and performs the input fie form for structure analysis only by input general data. User can mode1 space frame efficiently within shut time by using this program.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.229-234
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• 2007

In the structural analysis of the Korean traditional wooden structure, while the understanding of the transfer mechanism of roof load is very important, there are few researches on this subject. So, some modeling methods considering the connecting methods of the Korean traditional wooden structure are suggested, the results using each modeling method are compared, and the most reasonable analytical model is presented in this study.

• 한국CDE학회논문집
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• 제3권1호
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• pp.68-85
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• 1998

Solid modeling refers to techniques for unambiguous representations of three-dimensional objects. Feature recognition is a sub-discipline focusing on the design and implementation of algorithms for detecting manufacturing information such as holes, slots, etc. in a solid model. Automated feature recognition has been an active research area in stolid modeling for many years, and is considered to be a critical component for CAD/CAM integration. This paper gives a technical overview of the state of the art in feature recognition research. Rather than giving an exhaustive survey, I focus on the three currently dominant feature recognition technologies: graph-based algorithms, volumetric decomposition techniques, and hint-based geometric reasoning. For each approach, I present a detailed description of the algorithms being employed along with some assessments of the technology. I conclude by outlining important open research and development issues.

• 한국CDE학회논문집
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• 제19권1호
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• pp.29-40
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• 2014

Conceptual Modeling is the process of abstracting a model from a real or proposed system. It is probably the most important aspect of a simulation study. Relate works show that the elementary developers devoted little time to understanding how the systems actually worked, namely they didn't build appropriate conceptual model. Thus, the result of simulation is inconsistent because it depends on developer's competence. Although many researchers suggested various techniques enabling developer to build conceptual model, there were several limitations. In this study, to overcome the limitations of existing techniques, we proposed COMBINE-DES (COnceptual Model BuildINg framEwork using ontology for Discrete Event Simulation). The COM-BINE-DES supports expediting the conceptual modeling with Solution ontology generated by Domain ontology and Simulation ontology. Moreover, it provides consistent simulation result regardless of repeated modeling.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.169-176
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• 2003

In the present study, a shape design optimization scheme in shell structures is implemented based on the integrated framework of geometric modeling and analysis. The common representation of B-spline surface patch is used for geometric modeling. A geometrically-exact shell finite element is implemented. Control points or the surface are employed as design variables. In the computation of shape sensitivity, semi-analytical method is employed. Sequential linear programming is applied to the shape optimization of surfaces. The developed integrated framework should serve as a powerful tool to design and analysis of surfaces.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 봄 학술발표회 논문집
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• pp.415-429
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• 2002

Various modeling techniques for ultrasonic wave propagation and scattering problems in finite solid media are presented. Elastodynamic boundary value problems in inhomogeneous multi-layered plate-like structures are set up for modal analysis of guided wave propagation and numerically solved to obtain dispersion curves which show propagation characteristics of guided waves. As a powerful modeling tool to overcome such numerical difficulties in wave scattering problems as the geometrical complexity and mode conversion, the Boundary Element Method(BEM) is introduced and is combined with the normal mode expansion technique to develop the hybrid BEM, an efficient technique for modeling multi-mode conversion of guided wave scattering problems.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 봄 학술발표회 논문집
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• pp.53-60
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• 1997

The strain localization of concrete is a phenomenon such that the deformation of concrete is localized in finite region along with softening behavior. The objective of this paper is to develope a consistent algorithm for the finite element modeling of localized zone in the analysis of the strain-localization in concrete. For modeling of the localized zone in concrete under strain localization, a general Drucker-Prager failure criterion which can consider nonlinear strain softening behavior of concrete after peak-stress is introduce. The return-mapping algorithm is used for the integration of the elasto-plastic rate equation and the consistent tangent modulus is derived. Using finite element program implemented with the developed algorithms, strain localization behaviors for the different sizes of concrete specimen under compression are simulated.

• 전산구조공학
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• 제9권2호
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• pp.163-171
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• 1996

구조물 모니터링 시스템의 전산환경을 구성하기 위해 필요한 지식 및 정보를 파악하고 이를 지식기반화하는 방법을 제시하였다. 전산환경의 구축을 위한 정보로는 센서 및 하드웨어, 신호처리, 그리고 손상발견/평가를 위한 지식등이 필요한데, 이들은 모두 다른 형태의 지식이므로, -즉 수학연산, 서술적 지식, 수치모델등- 어느 특정의 모델링 기법 단독으로는 이들을 효과적으로 수용하기가 매우 어렵다. 이를 해결하기 위하여 객체지향적 모델링기법과 논리언어를 혼합사용하는 방법 (Hybrid Modeling Paradigm)이 제시되었고, 이의 타당성 및 효율성 검증을 위해 모델구조물을 이용한 예제를 수행하였다.

• 한국CDE학회논문집
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• 제14권4호
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• pp.261-270
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• 2009

We can save a lot of efforts and time to perform various kinds of multibody system dynamics simulations if the equations of motion of the multibody system can be formulated automatically. In general, the equations of motion are formulated based on Newton's $2^{nd}$law. And they can be transformed into the equations composed of independent variables by using velocity transformation matrix. In this paper the velocity transformation matrix is derived based on a topological modeling approach which considers the topology and the joint property of the multibody system. This approach is, then, used to formulate the equations of motion automatically and to implement a multibody system dynamics simulation program. To verify the the efficiency and convenience of the program, it is applied to the lifting simulation of a floating crane.