• Journal of KIISE:Computer Systems and Theory
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• v.31 no.10
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• pp.593-602
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• 2004

A new surface reconstruction scheme for approximating the surface from a set of unorganized 3D points is proposed. Our method, called shrink-wrapped boundary face (SWBF) algorithm, produces the final surface by iteratively shrinking the initial mesh generated from the definition of the boundary faces. Proposed method surmounts the genus-0 spherical topology restriction of previous shrink-wrapping based mesh generation technique, and can be applicable to any kind of surface topology. Furthermore, SWBF is much faster than the previous one since it requires only local nearest-point-search in the shrinking process. According to experiments, it is proved to be very robust and efficient for mesh generation from unorganized points cloud.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.628-630
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• 2004

정렬되지 않은 3차원 측정 점들로부터 이들을 근사하는 표면을 재구성하는 방법을 제안하였다. 제안된 방법은 경계면 축소포장 방식에 의한 표면 재구성 방법 (shrink-wrapped boundary face : SWBF)으로, 측정 점으로부터 경계셀과 경계면을 구해 초기 메쉬를 생성하고 이를 연속적으로 축소하는 방식에 의해 표면을 재구성한다 제안된 방법은 기존의 표면 축소포장 방식의 메쉬 생성 방법의 문제점인 물체의 토폴로지에 대한 제악이 없이 어떠한 형태의 표면 재구성에도 적용이 가능하며, 기존 방법이 축소 단계에서 각 메쉬 정점에 대한 최단거리 측정점을 찾는 전역 탐색을 해야 하는데 비해 지역 탐색만으로 최적의 측정 점을 찾을 수 있으므로 처리 시간 측면에서도 우월하다. 실험을 통해 제안된 표면 재구성 알고리즘이 측정 점들간의 관계를 알 수 없는 정렬되지 않은 3차원 정들에 대한 표면 재구성에 매우 안정적이고 효과적임을 확인할 수 있었다.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2007.10a
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• pp.247-256
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• 2007

Accessibility is a field of study that has primarily been applied to urban or transportation problems two dimensionally. However, in large complex buildings as shopping centers or hospitals, inter-spatial accessibility among compartments has to be taken into account such as in building layouts or evacuation planning. This study expands space syntax theory, one of accessibility-related methodologies used for computing connectivity in urban or architectural spaces, into 3D indoor spaces. Although space syntax is basically a topology-based theory that does not consider general costs such as distance or time, this study suggests modification that incorporates different types of impedances in moving between places including distances, turns and transfers between floors. The proposed method is applied to a 3D campus building model in computing and displaying the accessibility to exit doors or cohesive accessibility among similar functions.

• Convergence Security Journal
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• v.23 no.1
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• pp.3-8
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• 2023

Multi-domain optical transport networks are not fundamentally interoperable and require an integrated orchestration mechanism and path provision mechanism at the entire network level. In addition, ensuring network survivability is one of the important issues. MPLS-TP (Multi-Protocol Label Switching-Transport Profile) defines various protection/recovery methods as standards, but does not mention how to calculate and select protection/recovery paths. Therefore, an algorithm that minimizes protection/recovery collisions at the optical circuit packet integrated network level and calculates and sets a path that can be rapidly protected/recovered over the entire integrated network area is required. In this paper, we proposed an algorithm that calculates and sets up a path that can be rapidly protected and restored in a T-SDN network composed of multiple ring-mesh topology.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.2
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• pp.57-65
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• 2008

The improvement of the performance in laser radar simulation requires fast retrievals of the spatial locations and attributes of objects in response to the laser signals of the simulators. Since the data used in simulation are complex 3D objects such as terrain, buildings and vehicles, and are of large sizes, commonly used 3D modeling tools are not suitable for this use. We proposed a method to store such 3D objects in a database, perform required queries and integrate with visualization tools. We showed the processes for the data modeling based on 3D topological concepts and then building a spatial DBMS. Also, we illustrated the process for accessing and visualizing the stored data using VRML and performed test computations using some laser signal data. With further enhancement on data modeling and LOD problems in visualization, the proposed method will be practically applied in different situations including laser simulation.

• Fire Science and Engineering
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• v.25 no.6
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• pp.156-167
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• 2011

The number of buildings is growing at a rapid pace in Korea. It is driven by significant economic improvements, the rapid population growth and urban centralization. Such being this case, some city are underway to building enlargement, Manhattanization. To Solve these problem and ensure the safety of live, fire Evacuation Simulation system is used for safe check of buildings. Forecasting an egress behavior in building fire is so important in order to construct a safe and reliable environment. But, currently most of the fire evacuation simulation system used in practice are foreign software that is not reflect korean conditions. Thus, This study focus on objectives that develop a fire evacuation system considering Korean Characteristics and create 3D space-based topology. so the system calculate evacuation path. This system developed as a result of research can be used by architectural designer in practice due to it is based 3D spatial information modeling.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.3
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• pp.97-107
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• 2009

Experiments using real guided weapons for the development of the LADAR(Laser radar) are not practical. Therefore, we need computing environment that can simulate the 3D detections by LADAR. Such simulations require dealing with large sized data representing buildings and terrain over large area. And they also need the information of 3D target objects, for example, material and echo rate of building walls. However, currently used 3D models are mostly focused on visualization maintained as file-based formats and do not contain such semantic information. In this study, as a solution to these problems, a method to use a spatial DBMS and a 3D model suitable for LADAR simulation is suggested. The 3D models found in previous studies are developed to serve different purposes, thus, it is not easy to choose one among them which is optimized for LADAR simulation. In this study, 4 representative 3D models are first defined, each of which are tested for different performance scenarios. As a result, one model, "Body-Face", is selected as being the most suitable model for the simulation. Using this model, a test simulation is carried out.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.10
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• pp.1-10
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• 2000

A rigorous modeling of ultra-low energy implantation is becoming increasingly more important as devices shrink to deep submicron dimensions. In this paper, we have developed an efficient three-dimensional Monte Carlo ion implantation model based on a modified Binary Collision Approximation(BCA). To this purpose, the modified electronic stopping model and the multi-body collision model have been taken into account in this simulator. The dopant and damage profiles show very good agreement with SIMS(Secondary Ion Mass Spectroscopy) data and RBS(Rutherford Backscattering Spectroscopy) data, respectively. Moreover, the ion distribution replica method has been implemented into the model to get a computational efficiency in a 3D simulation, and we have calculated the 3D Monte Carlo simulation into the topographically complex structure.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.610-615
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• 2003

This experiment has been carried out to find the structure of turbulent boundary layer with instantaneous velocity fields obtained in stream-wall-normal planes using a stereo-PIV (Particle Image Velocimetry) method. And it has been measured perpendicular plane and horizontal plane with hairpin vortex structure by Reynolds number change and made third dimension shape for section of horizontal plane through stereo-PIV. In the outer layer hairpin vortices occur in streamwise-aligned packets that propagate with small velocity dispersion. A streaky structure is composed of counter-rotating vortex. According as y+ increases, streaky structure's interval space decrease, and it shows that hairpin shape of prior research is vertified. The objective of the present research is to gain a better understanding of coherent structures in the outer of wall turbulence by experimentally examining coherent structures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.10
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• pp.1139-1145
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• 2014

Creation of a human skeleton model and characterization of the variation in the bone shape are fundamentally important in many applications of biomechanics. In this paper, we present a parametric shape modeling method for femurs that is based on extracting the main parameter of variations of the femur shape from a 3D model database by using statistical shape analysis. For this shape analysis, principal component analysis (PCA) is used. Application of the PCA to 3D data requires bringing all the models in correspondence to each other. For this reason, anatomical landmarks are used for guiding the deformation of the template model to fit the 3D model data. After subsequent application of PCA to a set of femur models, we calculate the correlation between the dominant components of shape variability for a target population and the anatomical parameters of the femur shape. Finally, we provide tools for visualizing and creating the femur shape using the main parameter of femur shape variation.