• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.982-986
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• 2005

Digital Manufacturing is a technology to facilitate effective product developments and agile productions by digital environments representing the physical and logical schema and the behavior of real manufacturing system including manufacturing resources, processes and products. A digital virtual factory as a well-designed and integrated environment is essential for successful applications of this technology. In this research, we constructed a sophisticated digital virtual factory by measuring and 3-D CAD modeling using parametric methods. Specific parameters of each objects were decided by object-oriented schema of the digital factory. It is expected that this method is very useful for constructions of a digital factory, and helps to manage diverse information and re-use 3D models.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.573-577
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• 2009

최근 건설업계에서는 3D객체기반인 Building Information Modelling(이하 BIM)에 대해 관심이 증가하기 시작했다. 하지만 BIM도입에 어려움을 격고 있는 것이 현실이며 특히 전통적인 정보교환 방식에서의 BIM을 적용하는데 가장 큰 어려움을 격고 있다. 현재 국내에 활용되는 전자도면 표준지침에는 BIM도입에 필요한 2D표준에 대한 내용은 없으며, BIM소프트웨어들도 이 부분에 대해서 충분히 커스터마이징 되지 않았다. 이는 BIM과도기에 2D도면의 필요성을 인식한다면 원할한 BIM도입을 위해서 반드시 그 대안이 필요하다. 따라서 본 논문에서는 국내 BIM 도입 시 국내 2D 전자도면표준을 고려한 BIM 모델에서의 원할한 2D도면추출에 대해 Template을 활용하는 방안을 제안하였다. 도면표준의 기준은 "건설CALS/EC 전자도면 작성 표준"에 근거 하여 표현기준 및 데이터 작성기준을 Template파일에 적용 시켰으며, 이 후 실험을 통해 BIM 도입 시 효율적인 도면 생산의 가능성을 확인 하였다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.2
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• pp.196-204
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• 2016

World Health Organization reported that heart-related diseases such as coronary artery stenoses show the highest occurrence rate which may cause heart attack. Using Computed Tomography angiography images will allow radiologists to detect and have intervention by creating 3D roadmapping of the vessels. However, it is often complex and difficult do reconstruct 3D vessel which causes very large amount of time and previous researches were studied to segment vessels more accurate automatically. Therefore, in this paper, Region Competition, Geodesic Active Contour (GAC), Multi-atlas based segmentation and Active Shape Model algorithms were applied to segment aortic root from CTA images and the results were analyzed by using mean Hausdorff distance, volume to volume measure, computational time, user-interaction and coronary ostium detection rate. As a result, Extracted 3D aortic model using GAC showed the highest accuracy but also showed highest user-interaction results. Therefore, it is important to improve automatic segmentation algorithm in future

• Journal of KIISE
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• v.41 no.11
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• pp.927-934
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• 2014

In this paper, we propose an effective method for recognizing daily human activities from a stream of three dimensional body poses, which can be obtained by using Kinect-like RGB-D sensors. The body pose data provided by Kinect SDK or OpenNI may suffer from both the view variance problem and the scale variance problem, since they are represented in the 3D Cartesian coordinate system, the origin of which is located on the center of Kinect. In order to resolve the problem and get the view-invariant and scale-invariant features, we transform the pose data into the spherical coordinate system of which the origin is placed on the center of the subject's hip, and then perform on them the scale normalization using the length of the subject's arm. In order to represent effectively complex internal structures of high-level daily activities, we utilize Hidden state Conditional Random Field (HCRF), which is one of probabilistic graphical models. Through various experiments using two different datasets, KAD-70 and CAD-60, we showed the high performance of our method and the implementation system.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.66-74
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• 1996

In this paper, a 3-dimensional ship structural model which includes the longitudinals and stiffeners is constructed. This model can be constructed from the well-defined data structure which represents the ship structural members and their relationship. So the object-oriented concept for the data structure is introduced. The structural analysis model is automatically generated by extracting the necessary information for structural analysis from the ship structural model : Users need to handle the ship structural model only when any design change occurs because the structural analysis model is automatically generated.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.1
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• pp.52-62
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• 2017

Overseas landscape practices have already benefited from the awareness of BIM while landscape-related organizations are encouraging its use and the number of landscape projects using BIM is increasing. However, since BIM has not yet been introduced in the domestic field, this study investigated and analyzed overseas landscape projects and discussed the positive effects and implementation of BIM. For this purpose, landscape projects were selected to show three effects of BIM: improvement of design work efficiency, building of a platform for cooperation, and performance of topography design. These three projects were analyzed across four aspects of implementation methods: landscape information, 3D modeling, interoperability, and visualization uses of BIM. First, in terms of landscape information, a variety of building information was constructed in the form of 3D libraries or 2D CAD format from detailed landscape elements to infrastructure. Second, for 3D modeling, a landscape space including simple terrain and trees was modeled with Revit while elaborate and complex terrain was modeled with Maya, a professional 3D modeling tool. One integrated model was produced by periodically exchanging, reviewing, and finally combining each model from interdisciplinary fields. Third, interoperability of data from different fields was achieved through the unification of file formats, conversion of differing formats, or compliance with information standards. Lastly, visualized 3D models helped coordination among project partners, approval of design, and promotion through public media. Reviewing of the case studies shows that BIM functions as a process to improve work efficiency and interdisciplinary collaboration, rather than simply as a design tool. It has also verified that landscape architects could play an important role in integrated projects using BIM. Just as the introduction of BIM into the architecture, engineering and construction industries saw great benefits and opportunities, BIM should also be introduced to landscape architecture.

• Journal of KIBIM
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• v.1 no.1
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• pp.26-31
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• 2011

Due to the characteristics of 3D objects of building construction projects which have regular, vertical and repetitive shapes, the most practical utilization of BIM in the country is focused on building projects. The characteristics of 3D objects of civil engineering project have irregular, horizontal and non-repetitive shapes. Therefore, consisting of a practical BIM model is difficult comparing with building project. This study suggests an application process of BIM for the planning and design phases for civil engineering project. A BIM system is developed based on suggested BIM process and it is verified through a bridge construction project.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.1
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• pp.31-41
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• 2018

This paper discusses a structure design and thermal analysis of cryogenic conduction cooling system for a high current HTS DC reactor. Dimensions of the conduction cooling system parts including HTS magnets, bobbin structures, current leads, support bars, and thermal exchangers were calculated and drawn using a 3D CAD program. A finite element method model was built for determining the optimal design parameters and analyzing the thermo-mechanical characteristics. The operating current and inductance of the reactor magnet were 1,500 A, 400 mH, respectively. The thermal load of the HTS DC reactor was analyzed for determining the cooling capacity of the cryo-cooler. Hence, we carried out the operating test of conduction cooling system of the 1st stage area with high current flow. The cooper bars was cooled down to 40 K and HTS leads operated stably. As a experiment result, the total heat load of the 1st stage area is 190 W. The study results can be effectively utilized for the design and fabrication of a commercial HTS DC reactor.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.420-425
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• 2003

Generally, reverse engineering means getting CAD data from unidentified shape using vision or 3D laser scanner system. In this paper, we studied unidentified model by machine vision based reverse engineering system to get information about in-processing model. Recently, vision technology is widely used in current factories, because it could inspect the in-process object easily, quickly, accurately. The following tasks were mainly investigated and implemented. We obtained more precise data by corning camera's distortion, compensating slit-beam error and revising acquired image. Much more, we made similar curves or surface with B-spline approximation for precision. Until now, there have been many case study of shape recognition. But it was uncompatible to apply to the field, because it had taken too many processing time and has frequent recognition failure. This paper propose recognition algorithm that prevent such errors and give applications to the field.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2235-2245
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• 2000

The necessity of using rapid prototyping(RP) for short-run manufacturing is continuously driving a development of a cost-effective technique that will produce completely-finished quality parts in a very short time. To meet these demands, the improvements in production speed, accuracy, materials, aid cost are crucial. Thus, a new hybrid-RP system performing both deposition and machining in a station is proposed. For the new hybrid RP process to maintain the same degree of process automation as in currently available processes like SLA or FDNI, a sophisticated process planning system is developed. In the process planner, CAD models(STEP AP203) are partitioned into 3D manufacturable volumes called 'Ueposition feature segment"(DFS) after machining features called "machining feature segmenf'(MFS) are extracted from the initial CAD model. Once MFS and DFS are identified, the process planner arranges them into a chain of processes and automatically generates machining information for each DFS and MFS. The goal of this paper is to present a framework for a process planning system for hybrid RP processes and to outline the geometric algorithms involved in developing such an environment.