• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.10
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• pp.1075-1084
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• 2014

It is necessary to construct an equipment catalog in plant design. A different level of detail may be needed for the three-dimensional (3D) computer aided design (CAD) data for equipment, depending on the purpose. Equipment suppliers provide CAD data with high complexity, whereas plant designers need CAD data with low complexity. Therefore, it is necessary to simplify the 3D CAD assembly data. To resolve this issue, a system for automatically simplifying the 3D CAD assembly data of equipment was developed. This paper presents the architecture of the system, the detailed functions of the system, and a neutral data format used for uploading simplified 3D CAD assembly data to a plant 3D CAD system. In addition, experiment results using the prototype system are explained.

• Journal of the Korea Fashion and Costume Design Association
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• v.9 no.1
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• pp.103-122
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• 2007

Fashion have been expressed by a face through various a period, social change, and various culture changing. Human expresses as "Transformation" by applying these needs of changing to the fashion. A origin tribe expressed its own self by using direct body transformation and extreme decorations in the past. However, human express creative and esthetic desire based on shape, material, and transformation method in the present time characteristics of the body. Exceptional transformation breaking a existing fixed idea appeared frequently due to dissolution through transformation which is positive expression method in the fashion from 20th century. As a results, followings are obtained in this study. First, human body transforms by using a tool or intermediation in investigation of aesthetic meaning for human body. The object, Transformation, is stably transformed by disintegration, distortion, exaggeration and simplification reduction, as design's sensitivity. Second, transformation from relation of clothing composition is expressed by extension, reduction, simplification, and dissolution. In transformation from original tribe's sensitivity, past decorative desire lead to transformation of human body. To give variable change from past to present fashion, external formative will is introduced. Then, extreme expression is made by direct transformation of clothing type. It seems to be accomplished that human body's expression method is continuously changed into extension, exaggeration, reduction, and dissolution from transformation method as described before. Transformation of modem fashion is expression method by creative supervision. Extreme transformation substituted body's each part is based on immanent play and representative satisfaction. Through these transformation, it is judged that variety of creative type is achieved.

• Journal of Korea Multimedia Society
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• v.7 no.2
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• pp.231-240
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• 2004

Location Based Service(LBS) system is widely used in Car Navigation Service(CNS), position tracing, tour guide, etc. Recently, the development of a mobile hardware enables us to run various application of software on small handset. Although CNS systems are widely used on personal computer, PDA and embedded machines, small display system of a mobile handset still constrains to make it difficult to developed route visualization and navigation system. In this paper, we propose a new route map visualization system on mobile handset environment for LBS system. We use modified line simplification algorithm that removes extraneous information and places more emphasis on the turning point. We also adopted level of detail route visualization technique for visualization of a detail map. This system improved turn-by-turn method and line drive system, which are widely adopted by current route visualization system.

• Journal of the Korea Computer Graphics Society
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• v.4 no.1
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• pp.1-10
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• 1998

The idea of level-of-detail based on multiresolution model is gaining popularity as a natural means of handling the complexity regarding the realtime rendering of virtual environments. To generate an effective multiresolution model, we should capture the prominent visual features in the process of simplifying original complex model. In this paper, we incorporate view dependent features such as silhouette features and backface features, to the generation process of multiresolution model. To capture the view directional parameter, we propose multiresolution view sphere. View sphere maps the directional relationship between object surface and the view. Using the view sphere, coherence in the directional space is mapped into spatial coherence in the view sphere. View sphere is generated in multiresolution fashion to simplify the object. To access multiresolution view sphere efficiently, we devise quad tree for the view sphere. We also devise a mechanism for realtime simplification process using proposed view sphere. Using proposed mechanism, regenerating simplified model in realtime is effectively done in the order of number of rendered vertices.

• Journal of Korea Multimedia Society
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• v.17 no.1
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• pp.69-76
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• 2014

It is hard to represent massive terrain data in real-time even using recent graphics hardware. In order to process massive terrain data, mesh simplification method such as continuous Level-of-Detail is commonly used. However, existing GPU-based methods using quad-tree structure such as geometry splitting, produce lots of vertices to traverse the quad-tree and retransmit those vertices back to the GPU in each tree traversal. Also they have disadvantage of increase of tree size since they construct the tree structure using texture. To solve the problem, we proposed GPU-base chunked LOD technique for real-time terrain rendering. We restrict depth of tree search and generate chunks with tessellator in GPU. By using our method, we can efficiently render the terrain by generating the chunks on GPU and reduce the computing time for tree traversal.

• School Mathematics
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• v.9 no.4
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• pp.467-486
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• 2007

In mathematical modeling activity modeling process is usually an iterative process. When model can not be solved, the model needs to be simplified by treating some variables as constants, or by ignoring some variables. On the other hand, when the results from the model are not precise enough, the model needs to be refined by considering additional conditions. In this study we investigate the role of spreadsheet model in model refinement and modeling process. In detail, we observed that by using spreadsheet model students can solve model which can not be solved in paper-pencil environment. And so they need not go back to model simplification process but continue model refinement. By transforming mathematical model to spreadsheet model, the students can predict or explain the real word situations directly without passing the mathematical conclusions step in modeling process.

• Steel and Composite Structures
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• v.28 no.5
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• pp.573-588
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• 2018

The objective of this paper is to investigate the mechanical performances of polygonal concrete-filled circular steel tubular (CFT) stub columns under axial loading through combined experimental and numerical study. A total of 32 specimens were designed to investigate the effect of the concrete strength and steel ratio on the compressive behavior of polygonal CFT stub columns. The ultimate bearing capacity, ductility and confinement effect were analyzed based on the experimental results and the failure modes were discussed in detail. Besides, ABAQUS was adopted to establish the three dimensional FE model. The composite action between the core concrete and steel tube was further discussed and clarified. It was found that the behavior of CFT stub column changes with the change of the cross-section, and the change is continuous. Finally, based on both experimental and numerical results, a unified formula was developed to estimate the ultimate bearing capacity of polygonal CFT stub columns according to the superposition principle with rational simplification. The predicted results showed satisfactory agreement with both experimental and FE results.

• Journal of the Korea Computer Graphics Society
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• v.10 no.2
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• pp.42-50
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• 2004

캐릭터 애니메이션 기술의 발달로 가상공간에 애니메이트되는 캐릭터의 수가 점점 증가되고 있으며, 캐릭터 자체 골격구조의 관절 개수와 캐릭터를 덮고 있는 메쉬의 폴리곤 개수도 점점 증가하는 추세이다. 따라서, 실시간 가상환경에서 다수의 캐릭터를 전처리 과정 없이 시뮬레이션할 경우 전체 군중시스템 성능의 저하가 예상된다. 본 논문에서는, 이러한 문제점을 해결하기 위해 모션 다단계(motion level-of-detail) 기법을 제시한다. 모션 단순화 기법은 캐릭터의 움직임을 제어하는 골격(관절)구조와 캐릭터의 형태를 시각적으로 표현하는 기하(메쉬)구조를 단순화 하는 방법으로 기존 동작과 단순화된 동작의 차이를 최소화 한다. 골격구조 단순화를 위한 JPC(joint posture clustering)방법은 특정 관절의 연속된 모션 시퀀스에서의 유사 자세 집단을 추출하여 하나의 자세로 표현하는 방법으로, 모션의 특성에 따라 동적으로 관절을 단순화하여 관절 시뮬레이션 시간을 줄이는 방법이다. JPC방법은 골격구조가 시간에 따라 동적으로 변형되기 때문에 골격구조의 계층구조를 재 구축할 시간이 필요하지만, 기존 동작과 유사성을 잃지 않는 단순화된 동작 생성이 가능하다. 유사 자세 집단을 추출하기 위해 전체 모션 시퀀스에서 관절의 프레임간 자세 차이를 수식화하여 테이블 형태로 구성하고 이를 통해 기존 동작의 유사성을 잃지 않으며 관절의 단순화 율을 최대화 할 수 있는 알고리즘을 제시한다. 또한, 실시간 군중 환경의 성능을 더욱 향상시키기 위해 시간에 따라 변형되는 캐릭터 메쉬의 단순화 기법을 적용한다. 실험결과 모션 다단계 기법은 실시간 군중환경에서 캐릭터의 수가 많고 복잡한 골격구조와 기하구조로 구성된 관절 궤적의 변화가 심하지 않은 동작에 대해 특히 효율적이다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.3
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• pp.251-260
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• 2009

Hybrid locomotive UGV with actively articulated legs along with wheeled ends has high traversability to travel over rough terrain. The behavior control method was usually adapted for the controlling of the suspension configuration which determines the traversability of the UGV. In this study, we are proposing a method of configuration planning of the legs without any detail geometric data about the terrain. The terrain was estimated by the traces of each wheel and the leg configurations for the desired posture of the vehicle were set up against the constraints of the terrain. Also, an optimal leg configuration was calculated based on the quasi-static stability and power consumption, and plans for the leg behavior were made. Validity of the proposed method was checked by simulations using some off-the-shelf programs, and showed that the orientation control without geometric features of terrains and simplification of the behavior planning for obstacle negotiation were possible.

• The Journal of Korean Medical History
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• v.28 no.1
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• pp.103-109
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• 2015

We have summarized a large part of the history of Korean medicine from a macroscopic perspective. However, many aspects still remain incomplete from a microscopic perspective. This is partly because the society under the Chosun dynasty was dominated by the gentry class and they were not active in the field of medicine. However, another reason is that, unlike the Chinese, these people left behind few medical case records (醫案, eui-an) that vividly describe the treatment methods prevalent during those times. This may be attributed to the fact that during those times, the focus of medical doctors was not on recording their knowledge and experiences, but on simplification of diagnosis and treatments for practical use. However, since medical case records of any era provide an insight into the state of medical provision at that time, they could play an important role in providing concrete knowledge regarding the state of medicine under the Chosun dynasty, and in understanding the uniqueness of Korean medicine in detail. Therefore, in this article we discuss the recently discovered Gyeongheombang (經驗方), which is archived at the Korea University, and through this we aim to add a new source of detailed information on Korean medicine, and to identify the potential of Korean medicine by demonstrating its uniqueness.