• 대한전자공학회논문지TC
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• 제43권2호
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• pp.39-43
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• 2006

본 논문은 잡음이 존재하는 미지 시스템 출력 신호의 3차 통계치인 cumulant를 이용한 AR 식별에 관한 것이다. 미지 시스템 식별을 위한 알고리즘에서는 Parametric Modeling 기법중에서 Global Convergence 보장 및 시스템의 진폭과 위상 정보를 모두 표현할 수 있는 Cumulant를 이용한 AR (Auto Regressive) 식별 방법을 적용하였다. 식별 과정에서 미지 시스템을 하나의 AR 시스템으로 간주하였고 입력 신호를 발생하여 이를 통과시킨 후 잡음이 부가된 출력 신호를 얻어 이를 이용하였다. 신호대 잡음비의 변화에따른 AR 시스템의 식별을 수행한 결과 원래의 시스템 출력치와 유사한 양호한 식별 결과를 얻을 수 있었고 극점이 z 변환의 단위원내에 존재함을 확인하였다.

• 교육시설 논문지
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• 제20권5호
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• pp.11-18
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• 2013

This study has revisited the definition and characteristics of BIM to contribute to the better understanding of this concept. For the successful application of BIM in architectural design field, it should start with public buildings like schools which can be standardized. Since a number of conditions of school design appear to suit the schematic design phase for BIM application more than do other types of building design, the viability of BIM was examined by applying parametric modeling(one of BIM's basic characteristics) to mass study in schematic design phase for the configuration of schools that adopt the variation type of subject classroom design of the $7^{th}$ National Educational Curriculum. In addition, this modeling technique was used with software of Rhino 3D and Grasshopper, which will have a linkage to environmental analysis in near future. Finally, it can be expected that the work efficiency will be maximized if BIM is going to be applied in the early design stage instead of the end stage.

• Structural Engineering and Mechanics
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• 제61권4호
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• pp.497-510
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• 2017

A framed structure may be composed of two sub-structures, which are linked by a hinged joint. One sub-structure is the primary system and the other is the secondary system. The primary system, which is subjected to the periodic external load, can give rise to an auto-parametric resonance of the second system. Considering the geometric-stiffness effect produced by the axially internal force, the element equation of motion is derived by the extended Hamilton's principle. The element equations are then assembled into the global non-homogeneous Mathieu-Hill equations. The Newmark's method is introduced to solve the time-history responses of the non-homogeneous Mathieu-Hill equations. The energy-growth exponent/coefficient (EGE/EGC) and a finite-time Lyapunov exponent (FLE) are proposed for determining the auto-parametric instability boundaries of the structural system. The auto-parametric instabilities are numerically analyzed for the two frames. The influence of relative stiffness between the primary and secondary systems on the auto-parametric instability boundaries is investigated. A phenomenon of the "auto-parametric internal resonance" (the auto-parametric resonance of the second system induced by a normal resonance of the primary system) is predicted through the two numerical examples. The risk of auto-parametric internal resonance is emphasized. An auto-parametric resonance experiment of a ${\Gamma}$-shaped frame is conducted for verifying the theoretical predictions and present calculation method.

• 한국BIM학회 논문집
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• 제2권2호
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• pp.17-26
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• 2012

This paper presents the results of a theoretical energy analysis of a research test bed called the Zero Net Energy Test House (ZNETH) in Omaha, Nebraska in U.S.A. The ZNETH project is being designed and built with the goal of consuming a negligible amount of energy by offsetting remaining usage after energy conservation. The theoretically consumed and generated energy levels were analyzed using energy modeling software programs. By integrating a highly graphical and intuitive analysis with a Building Information Model(BIM) of the house, this investigation introduces strategies to include sustainable materials and systems to predict energy generation with a case study of ZNETH. In addition, this paper introduces parametric analyses for better envelope design and construction material selection by analyzing simulated energy consumption with various parametric inputs, e.g., material types, location, and size. It was found that the current design of ZNETH does not meet its goal of zero net energy. Sugeestions are presented to assist ZHETH in meeting its net zero energy goal.

• Structural Engineering and Mechanics
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• 제31권3호
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• pp.297-314
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• 2009

When the temperature of a structure varies, there is a tendency to produce changes in the shape of the structure. The resulting actions may be of considerable importance in the analysis of the structures having non-prismatic members. Therefore, this study aimed to investigate the modeling, analysis and behavior of the non-prismatic members subjected to temperature changes with the aid of finite element modeling. The fixed-end moments and fixed-end forces of such members due to temperature changes were computed through a comprehensive parametric study. It was demonstrated that the conventional methods using frame elements can lead to significant errors, and the deviations can reach to unacceptable levels for these types of structures. The design formulas and the dimensionless design coefficients were proposed based on a comprehensive parametric study using two-dimensional plane-stress finite element models. The fixed-end actions of the non-prismatic members having parabolic and straight haunches due to temperature changes can be determined using the proposed approach without necessitating a detailed finite element model solution. Additionally, the robust results of the finite element analyses allowed examining the sources and magnitudes of the errors in the conventional analysis.

• 동력기계공학회지
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• 제13권5호
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• pp.46-51
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• 2009

Recently, the shock resistance and dynamic characteristics of hard disk drives have become more important due to their highly increased storage density and miniaturization. In this study, we have developed an ANSYS/Mechanical/LS-DYNA based HDD vibration/shock simulation tool for design engineers. This simulation tool using ANSYS APDL can produce a parametric finite element modeling of HDD automatically and has GUI-based applications using the script program language Tcl/Tk. In the present tool, we adopt the reliable methodology of vibration/shock simulation, which is experimentally verified. It is expected that this simulation tool can make the repetitive computational efforts for the shock-proof design of HDD drastically reduced.

• Journal of Welding and Joining
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• 제32권3호
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• pp.1-10
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• 2014

The efficient application of any welding process depends on the understanding of associated process parameters influence on the weld quality. The weld quality includes the weld bead dimensions, temperature distribution, metallurgical phases and the mechanical properties. A detailed review on the experimental and numerical approaches to understand the parametric influence of a single wire submerged arc welding (SAW) and multi-wire SAW processes on the final weld quality is reported in two parts. The first part deals with the experimental approaches which explain the parametric influence on the weld bead dimensions, metallurgical phases and the mechanical properties of the SAW weldment. Furthermore, the studies related to statistical modeling of the present welding process are also discussed. The second part deals with the numerical approaches which focus on the conduction based, and heat transfer and fluid flow analysis based studies in the present welding process. The present paper is the first part.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1882-1887
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• 2003

The response surface method (RSM) became one of famous meta modeling techniques, however its approximation errors give designers several restrictions. Classical RSM uses the least squares method (LSM) to find the best fitting approximation models from the all given data. This paper discusses how to construct RSM efficiently and accurately using moving least squares method (MLSM) with sensitivity information. In this method, several parameters should be determined during the construction of RSM. Parametric study and optimization for these parameters are performed. Several difficulties during approximation processes are described and numerical examples are demonstrated to verify the efficiency of this method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.214-216
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• 1998

Parameterizing a model is one of the most efficient ways of conducting "virtual prototying" i.e. exploring the "What if?" scenario. But it is very difficult to construct parameterized models in commercial based FEM programs, because they usually adopt the mouse inputs in their GUI, which cannot be parameterized. We consolidated a parametric modelling technique in OPERA-3d preprocessor, which is one of world leading electromagnetic analysis programs, by combining the mouse inputs in GUI with it's FORTRAN-based self script command language.

• 문화기술의 융합
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• 제7권1호
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• pp.92-98
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• 2021

합리성과 효율성을 끊임없이 요구받고 있는 현대사회의 시대적 흐름은 사회 전체의 패러다임이 되었다. 이 패러다임은 건축설계와 건설업계에도 큰 영향을 미치고 있다. 디지털 도구의 발전과 인터넷을 통한 정보기술(Information Technology)로 대변되는 현대 기술은 건축설계와 건설업계에서 파라메트릭 디자인(Parametric Design)과 BIM(Building information Modeling)이라는 두 개의 큰 흐름을 생성하고 발전하고 있다. 비록 각기 다른 이유로 탄생했으나 효율성과 합리성이라는 공통의 목적으로 서로의 경계를 넘나들면서 건축설계와 건설업계에 큰 영향력을 보이고 있다. 이러한 맥락에서 본 연구는 BIM 설계에 적용을 초기 기획설계단계에서의 파라메트릭 디자인이 어떻게 이루어져야 하는지에 대한 내용을 예시를 통해 구현해 보고자 했다. 해체주의(Deconstructivism) 건축가 "프랭크 게리"(Frank O. Ghery)의 작품인 월트디즈니 홀(Walt Diseny Consert Hall) 설계의 프로세스에 대한 고찰과 체코프라하의 네덜란덴 빌딩(National Nederlanden Building)의 형태를 파라메트릭 설계 툴(Tool)을 사용하여 기획설계단계에서의 형태를 구현하고자 했다. 향후 이 연구는 기획설계단계에서의 파라메트릭 디자인의 범위를 넘어서 궁극적인 BIM의 적용 즉 계획 및 실시설계 그리고 시공에 이르는 건설산업 전반에 적용 가능한 기초 자료로서의 목적에 사용되고자 한다. 향후 파라메트릭 디자인 알고리즘을 활용한 계획 및 실시설계단계에서의 BIM의 적용을 진행하고자 한다.