• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2006년도 학술대회 1부
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• pp.486-492
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• 2006

본 논문에서는 비디오에서의 특징점 추적을 통해 얻은 2D 좌표를 이용한 3D 구조를 추정하는 방법과 네 점 이상의 공통점을 이용한 융합 방법을 제안한다. 영상의 각 프레임에서 공통되는 특징점을 이용하여 형상을 추정한다. 영상의 각 프레임에 대한 특징점의 추적은 Lucas-Kanade 방법을 사용하였다. 3D 좌표 추정 방법으로 개선된 직교분해기법을 사용하였다. 개선된 직교분해기법에서는 3D 좌표를 복원함과 동시에 카메라의 위치와 방향을 계산할 수 있다. 복원된 부분 데이터들은 전체를 이루는 일부분이므로, 융합을 통해 완성된 모습을 만들 수 있다. 복원된 부분 데이터들의 서로 다른 좌표계를 기준 좌표계로 변환함으로써 융합할 수 있다. 융합은 카메라의 모션에 해당하는 카메라의 위치와 방향에 의존된다. 융합 과정은 모두 선형으로 평균 0.5초 이하의 수행 속도를 보이며 융합의 오차는 평균 0.1cm 이하의 오차를 보였다.

• 한국멀티미디어학회논문지
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• 제10권3호
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• pp.303-315
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• 2007

본 논문에서는 비디오에서의 특징점 추적을 통해 얻은 2차원 좌표를 이용하여 3차원 구조를 계산하고 부분적으로 복원된 형상들을 점진적으로 융합하여 전체 형상을 생성하는 기법을 제안한다. 영상의 각 프레임에서 공통적으로 추적된 특징점들을 이용하여 형상을 추정한다. 3차원 좌표 추정 방법으로 개선된 직교분해기법을 사용하였다. 개선된 직교분해기법에서는 3차원 좌표를 복원함과 동시에 카메라의 위치와 방향을 계산할 수 있다. 복원된 부분 형상의 융합을 통해 입체적인 전체 형상을 만든다. 복원된 부분 데이터들의 서로 다른 좌표계를 기준 좌표계로 변환하여 하나의 전체 형상으로 융합한다. 형상 추정 과정과 융합 과정이 통합적으로 수행되며 반복적 최적화 작업을 수행하지 않고 선형적으로 이루어진다. 이는 기존 융합 방법인 ICP(Iterative Closest Point) 방법보다 융합 속도를 향상시켜 빠른 형상 복원이 가능하다. 융합 시간은 평균 0.01초 이내의 수행 속도를 보이며 융합의 오차는 평균 1.0mm 이하의 오차를 보였다.

• 한국기계가공학회지
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• 제14권3호
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• pp.15-20
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• 2015

After the US government declared 3D printing technology a next-generation manufacturing technology, there have been many practical studies conducted to expand 3D printing technology to manufacturing technologies, called AMERICA MAKES. In particular, the Keck Center, located at the University of Texas at El Paso, has studied techniques for easily combing the 3D stacking process with space mobility and expanded these techniques to simultaneous staking techniques for multiple materials. Additionally, it developed convergence manufacturing techniques, such as direct inking techniques, in order to produce a module structure that combines electronic circuits and components, such as CUBESET. However, in these studies, it is impossible to develop a unified system using traditional independent through simple sequencing connections. This is because there are many problems in the integration between the stacking modeling of 3D printers and post-machining, such as thermal deformations, the precision accuracy of 3D printers, and independently driven coordinate problems among process systems. Therefore, in this paper, the integration method is suggested, which combines these 3D printers and subsequent machining process systems through an Internet-based cloud. Additionally, the sequential integrated system of a 3D printer, an NC milling machine, machine vision, and direct inking are realized.

• Structural Engineering and Mechanics
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• 제75권3호
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• pp.357-367
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• 2020

The objective of this article is investigation of dynamic response of thick multilayer functionally graded (FG) beam under generalized dynamic forces. The plane stress problem is exploited to describe the constitutive equation of thick FG beam to get realistic and accurate response. Applied dynamic forces are assumed to be sinusoidal harmonic, sinusoidal pulse or triangle in time domain and point load. Equations of motion of deep FG beam are derived based on the Hamilton principle from kinematic relations and constitutive equations of plane stress problem. The numerical finite element procedure is adopted to discretize the space domain of structure and transform partial differential equations of motion to ordinary differential equations in time domain. Numerical time integration method is used to solve the system of equations in time domain and find the time responses. Numerical parametric studies are performed to illustrate effects of force type, graduation parameter, geometrical and stacking sequence of layers on the time response of deep multilayer FG beams.

• 한국CDE학회논문집
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• 제19권1호
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• pp.80-90
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• 2014

In architecture projects, BIM library has widely been using for prefabrication of products and design process. However, since the shape of structures is different by each project in civil engineering projects and a shape representation system is complicated, it is not easy to develop a standardized BIM library. To solve these issues, this study develops BIM library based on standardized 2D shop drawings for civil structures. The standardized shop drawings, which are the targets of the BIM library model, should be first selected. Besides, in order to define modeling scope with the level of general and shop drawings for each structure, LOD(Level of Detail) and breakdown structure are determined, and development methods of families of 3D object type including 2D profile and rebar through commercial software are established. With these, properties of BIM library are configured, and a utilization model of the BIM libraries is constructed for 3D modeling and a simulation using the BIM library. Therefore, this study can identify properties that are necessary when IFC schema is configured for civil engineering projects. For future, it is expected that easiness of BIM design for the civil engineering projects and generation, management, and analysis system of BIM library for road projects will be secured.

• 한국전산구조공학회논문집
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• 제30권1호
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• pp.71-76
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• 2017

BIM 설계에서 라이브러리의 구축 및 활용은 매우 중요하다. 기존 컨텐츠의 재활용이 가능하므로, 설계를 보다 효과적이고 효율적으로 진행할 수 있다. 건축분야와 달리 토목분야, 특히 철도시설분야에서는 라이브러리의 구축 및 표준화가 미진하다. 따라서 본 연구에서는 철도시설분야에 3차원 객체 라이브러리를 구축하고 표준화하고자 한다. 철도시설물 분류체계 및 관련도면을 수집 및 분석한다. 분석된 표준도면의 항목과 분류체계 항목을 매칭하였다. 각 항목별로 라이브러리가 필요한지 여부와 그럴 경우 어떤 소프트웨어가 적절한지를 검토하였다. 사용가능한 소프트웨어는 주로 Civil 3D와 Revit 등으로 나타났다. 향후 이를 바탕으로 철도인프라 3차원 라이브러리의 속성 항목 및 명세서를 설계하고 라이브러리를 구축할 예정이다.

• 한국항해항만학회지
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• 제30권2호
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• pp.131-136
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• 2006

Researches on a superstructure built on a floating structure in the shape of pontoon type have begun in recent years. A superstructure responds by wave load and it is important to evaluate its habitability. The purpose of this study is evaluation and investigation of habitability of a superstructure due to wave for 10 year return period. In this study, response analyses of the superstructure built on middle-sized floating structure due to the waves of three cases were carried out by 3-D integration analysis, which means analyzing the calculation model integrated a superstructure with a floating structure, and its habitability was evaluated by the evaluation diagrams. As the result, the habitability differed by each wave condition The use of a superstructure is restricted according to the disposition of a floating structure for incident wave angle.

• Structural Engineering and Mechanics
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• 제85권4호
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• pp.485-500
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• 2023

The non-linear static analysis of reinforced concrete (RC) structures using the three-dimensional (3D) finite element method is a time-consuming and challenging task. Moreover, this type of analysis encounters numerical problems such as the lack of convergence of results in the stages of growth and propagation of cracks in the structure. The time integration analysis along with the mass scaling (MS) technique is usually used to overcome these limitations. Despite the use of this method in the 3D finite element analysis of RC structures, a comprehensive study has not been conducted so far to assess the effects of the MS method on the accuracy of results. This study aims to evaluate the accuracy of the MS method in the non-linear quasi-static finite element analysis of RC structures. To this aim, different types of RC structures were simulated using the finite element approach based on the implicit time integration method and the mass scaling technique. The influences of effective parameters of the MS method (i.e., the allowable values of increase in the mass of the RC structure, the relationship between the duration of the applied load and fundamental vibration period of the RC structure, and the pattern of applied loads) on the accuracy of the simulated results were investigated. The accuracy of numerical simulation results has been evaluated through comparison with existing experimental data. The results of this study show that the achievement of accurate structural responses in the implicit time integration analyses using the MS method involves the appropriate selection of the effective parameters of the MS method.

• 한국BIM학회 논문집
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• 제8권2호
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• pp.1-9
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• 2018

Nowadays Building Information Modeling (BIM) is a significant source of sharing project information in the construction industry. This method of sharing the information enhances the project understanding among stakeholders. Modeling of information using BIM is becoming an essential part of many construction projects around the globe. Despite rapid adoption of BIM in construction industry still, some sectors of the industry like earthwork have not yet reaped its full benefits. BIM has brought a paradigm shift through identification and integration of the roles and responsibilities of project participants on a single platform. BIM is a 3D model-based process which provides the insight into the efficient project planning and design. The 3D modeling can also be used significantly for the design of temporary structures in an earthwork project. This paper presents the quantity take-off methodology and parametric modeling technique for creating the temporary structures using 3D BIM process. A case study is conducted to implement the proposed temporary structure family design on a real site project. The study presented is beneficial for the earthwork project stakeholders to extract the relevant information using 3D BIM models in a project. It provides an opportunity to calculate the quantity of material required for a project accurately.

• 한국항해항만학회지
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• 제36권3호
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• pp.175-180
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• 2012

플로팅 상부구조물은 일반 건축물과 형태는 같지만 기초가 땅이 아닌 하부 부체에 지지되는 구조물로 파랑하중에 의한 영향을 크게 받으며, 파랑하중에 의한 하부구조물의 변형이 접합부에 영향을 미쳐 상부구조물의 이용자에게 사용성 및 안전성의 문제를 발생시키게 된다. 이에 따라 본 논문에서는 3차원 플로팅 구조물의 상부구조물과 하부구조물을 일체화한 전해석을 통하여 강접합과 반강접 접합에 대해 탄성 해석을 실시하였다. 구조물의 전해석과 하부구조물을 제외한 분리해석을 비교 분석 하였으며 탄성 해석을 통해 파랑하중의 CASE를 나누어 파랑하중의 변화에 따른 구조물의 모멘트 및 변위를 접합부에 따라 분류하고 비교하였다.