• Korean Journal of Computational Design and Engineering
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• v.15 no.3
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• pp.212-221
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• 2010

Proposed in the paper is a methodology to generate kinematic template for 3D JIG models. Recently, according to increase of the rate of automatic facility in manufacturing system, the 3D manufacturing and verification research and development have been issued. So, unlike in the past, moving 3D facilities are very various like JIGs, turn table, AS/RS worked in the automated manufacturing industry. Because 3D mesh models are used in these kinds of 3D simulation, users have to define the kinematic information manually. This 3D mesh data doesn't have parametric information and design history of the 3D model unlike the design level data. So, it is lighter than 3D design level data and more efficient to render on the 3D virtual manufacturing environment. But, when user wants to find a common axis located between the links, the parameter information of the model has to reconstruct for defining kinematic construction. It takes a long time and very repetitive to define an axis and makes a joint using 3D mesh data and it is non-intuitive task for user. This paper proposed template model that provides kinematic information of the JIG. This model is kinds of a state diagram to describe a relation between links. So, this model can be used for a kinematic template to the JIG which has a same mechanism. The template model has to be registered in the template library to use in the future, after user made the model of the specific type of the 3D JIG model.

• Korean Journal of Construction Engineering and Management
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• v.23 no.2
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• pp.33-44
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• 2022

The simulation function by the 4D system is a representative BIM function in the construction stage. For the 4D simulation, schedule information for each activity must be created and then linked with the 3D model. Since the 3D model created in the design stage does not consider schedule information, there are practical difficulties in the process of creating schedule information for application to the construction stage and linking the 3D model. In this study, after extracting the schedule information of the construction stage using the HDBSCAN algorithm from the 3D model in the design stage, authors propose a methodology for automatically generating schedule information by identifying precedence and sequencing relationships by applying the topological alignment algorithm. Since the generated schedule information is created based on the 3D model, it can be used as information that is automatically linked by the common parameters between the schedule and the 3D model in the 4D system, and the practical utility of the 4D system can be increased. The proposed methodology was applied to the four bridge projects to confirm the schedule information generation, and applied to the 4D system to confirm the simplification of the link process between schedule and 3D model.

• The KIPS Transactions:PartD
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• v.17D no.4
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• pp.283-296
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• 2010

Timing diagram is a useful tool for describing the specification of system, but there is no study for test case strategy of a timing diagram. To solve this problem, we followed the steps to generate test cases from timing diagram in this paper. 1) We defined a timing diagram formally. 2) We describe the method of transforming from a timing diagram model into a Stateflow model which has an equivalent relationship between a timing diagram model and a transformed Stateflow model. 3) We generated test cases from a transformed Stateflow model using SDV which is plugged in Simulink. To show that our approach is useful, we made an experiment with a surveillance model and arbitrary timing diagram models. In the experiment we transformed timing diagram models into Stateflow models, generated test cases from transformed Stateflow models using SDV, and analyzed the generation results. The conclusion that can be obtained from this study is that timing diagram is not only a specification tool but also a useful tool when users are trying to generate test cases based on model.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.1
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• pp.122-126
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• 2008

Integrating a 3D solid modeler with a general purpose FEM code, an automatic stress intensity factor analysis system of the 3D crack problems has been developed. A geometry model, i.e. a solid containing one or several 3D cracks is defined. Several distributions of local node density are chosen, and then automatically superposed on one another over the geometry model by using the fuzzy knowledge processing. Nodes are generated and quadratic tetrahedral solid elements are generated by the Delaunay triangulation techniques. Finally, the complete finite element(FE) model generated, and a stress analysis is performed. This paper describes the methodologies to realize such functions, and demonstrates the validity of the present system.

• Korean Journal of Remote Sensing
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• v.28 no.3
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• pp.319-327
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• 2012

In this paper, we introduce a newly developed photogrammetric software for automatic generation of high quality geo-products and its performance assessment carried out using various satellite images. Our newly developed software provides the latest techniques of an optimized sensor modelling, ortho-image generation and automated Digital Elevation Model (DEM) generation for diverse remote sensing images. In particular, images from dual- and multi-sensor images can be integrated for 3D mapping. This can be a novel innovation toward a wider applicability of remote sensing data, since 3D mapping has been limited within only single-sensor so far. We used Kompsat-2, Ikonos, QuickBird, Spot-5 high resolution satellite images to test an accuracy of 3D points and ortho-image generated by the software. Outputs were assessed by comparing reliable reference data. From various sensor combinations 3D mapping were implemented and their accuracy was evaluated using independent check points. Model accuracy of 1~2 pixels or better was achieved regardless of sensor combination type. The high resolution ortho-image results are consistent with the reference map on a scale of 1:5,000 after being rectified by the software and an accuracy of 1~2 pixels could be achieved through quantitative assessment. The developed software offers efficient critical geo-processing modules of various remote sensing images and it is expected that the software can be widely used to meet the demand on the high-quality geo products.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.71-79
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• 2002

A new rapid prototyping process, Variable Lamination Manufacturing using a 4-axis-controlled hotwire cutter and expandable polystyrene foam sheet as a laminating material of the part (VLM-S), has been developed to reduce building time and to improve the surface finish of parts. The objective of this study is to reconstruct the surface of the original 3D CAD model in order to generate mid-slice data using the advancing front technique. The generation of 3D layers by a 4 axis-controlled hot-wire cutter requires a completely different procedure to generate toolpath data unlike the conventional RP CAD systems. The cutting path data for VLM-S are created by VLM-Slicer, which is a special CAD/CAM software with automatic generation of 3D toolpath. For the conventional sheet type system like LOM, the STL file would be sliced into 2D data only. However, because of using the thick layers and a sloping edge with the firstorder approximation between the top and bottom layers, VLM-Slicer requires surface reconstruction, mid-slice, and the toolpath data generation as well as 2D slicing. Surface reconstruction demands the connection between the two neighboring cross-sectional contours using the triangular facets. VLM-S employs thick layers with finite thickness, so that surface reconstruction is necessary to obtain a sloping angle of a side surface and the point data at a half of the sheet thickness. In the process of the toolpath data generation the surface reconstruction algorithm is expected to minimize the error between the ruled surface and the original parts..

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.496-500
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• 1997

This paper describes an automated system for analyzing the stress intensity factors(SIFs) of three-dimensional (3D) cracks. A geometry model, i.e.a solid containing one or several 3D cracks is defined. Several distributions of local node density are chosen, and then automatically superposed on one another over the geometry model by using the fuzzy knowledge processing. Nodes are generated by the bucketing method, and ten-noded quadratic tetrahedral solid elements are generated by the Delauuay triangulation techniques. The singular elements such that the mid-point nodes near crack fornt are shifted at the quarter-points are automatically placed along the 3D crack front. THe complete finite element (FE) model generated, i.e the mesh with material properties and boundary conditions is given to one of the commercial FE codes, and a stress analysis is performed. The SIFs are calculated using the displacement extrapolation method. To demonstrate practical performance of the present system, a semi- elliptical surface crack in a plate subjected to tension is solved.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.768-775
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• 2022

Current MEP designs are mostly applied by 2D-based design methods and tend to focus on simple modeling or geometry information expression such as converting 2D-written drawings into 3D modeling without taking advantage of the strength of BIM application. To increase the demand for BIM-based MEP design, geometric information, and property information of each member of the 3D model must be conveniently linked from the phase of the Design Development (DD) to the phase of Construction Document (CD). To conveniently implement a detailed model at each phase, the detailed level of each member of the 3D model must be specific, and an automatic generation of objects at each phase and automatic detailing module for each LOD are required. However, South Korea's guidelines have comprehensive standards for the degree of MEP modeling details for each design phase, and the application of each design phase is ambiguous. Furthermore, in practice, detailed levels of each phase are input manually. Therefore, this paper summarized the detailed standards of MEP modeling for each design phase through interviews with MEP design companies and related literature research. In addition, items that enable auto-detailing with DYNAMO were selected using the checklist for each design phase, and the types of detailed methods were presented. Auto-detailing items considering the detailed level of each phase were classified by members. If a DYNAMO algorithm is produced that automates selected auto-detailing items in this paper, the time and costs required for modeling construction will be reduced, and the demand for MEP design will increase.

• Journal of KIBIM
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• v.12 no.4
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• pp.19-31
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• 2022

With the development of 3D-based CAD (Computer Aided Design), attempts at freeform building design have expanded to small and medium-sized buildings in Korea. However, a standardized system for continuous utilization of shape data and BIM conversion process implemented with 3D-based NURBS is still immature. Without accurate review and management throughout the Freeform building project, interference between members occurs and the cost of the project increases. This is very detrimental to the project. To solve this problem, we proposed a continuous utilization process of 3D shape information based on BIM parameters. Our process includes algorithms such as Auto Split, Panel Optimization, Excel extraction based on shape information, BIM modeling through Adaptive Component, and BIM model utilization method using ID Code. The optimal cutting reference point was calculated and the optimal material specification was derived using the Panel Optimization algorithm. With the Adaptive Component design methodology, a BIM model conforming to the standard cross-section details and specifications was uniformly established. The automatic BIM conversion algorithm of shape data through Excel extraction created a BIM model without omission of data based on the optimized panel cutting reference point and cutting line. Finally, we analyzed how to use the BIM model built for automatic conversion. As a result of the analysis, in addition to the BIM utilization plan in the general construction stage such as visualization, interference review, quantity calculation, and construction simulation, an individual management plan for the unit panel was derived through ID data input. This study suggested an improvement process by linking the existing research on atypical panel optimization and the study of parameter-based BIM information management method. And it showed that it can solve the problems of existing Freeform building project.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.229-240
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• 2019

3D geo-spatial model have been widely used in the field of Civil Engineering, Medical, Computer Graphics, Urban Management and many other. Especially, the demand for high quality 3D spatial information such as precise road map construction has explosively increased, MMS and UAV techniques have been actively used to acquire them more easily and conveniently in surveying and geo-spatial field. However, in order to perform 3D modeling by integrating the two data set from MMS and UAV, its so needed an proper registration method is required to efficiently correct the difference between the raw data acquisition sensor, the point cloud data generation method, and the observation accuracy occurred when the two techniques are applied. In this study, we obtained UAV point colud data in Yeouido area as the study area in order to determine the automatic registration performance between MMS and UAV point cloud data using ICP(Iterative Closet Point) method. MMS observations was then performed in the study area by dividing 4 zones according to the level of overlap ratio and observation noise with based on UAV data. After we manually registered the MMS data to the UAV data, then compared the results which automatic registered using ICP method. In conclusion, the higher the overlap ratio and the lower the noise level, can bring the more accurate results in the automatic registration using ICP method.