• International Journal of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.8-19
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• 2019

Since their emergence in 2007, smart phones have advanced up to the point that 5G mobile communication in 2019 started to be commercialized. Accordingly, now it is possible to share 3D modeling files and collaborate by means of a mobile web. As the recently commercialized 5G mobile communication network is so useful in sharing 3D modeling files and collaborating that even large-size geometry files can be transmitted at ultra high speed with ultra low transfer delay. We examines characteristics of major 3D file formats such as STL, OBJ, FBX, and glTF and compares the existing 4G LTE (Long Term Evolution) network with the 5G NR (New Radio) mobile communication network. The loading time and packets of each format were measured depending on the mobile web browser environments. We shows that in comparison with 4G LTE, the loading time of STL and OBJ file formats were reduced as much as 6.55 sec and 9.41 sec, respectively in the 5G NR and Chrome browsers. The glTF file format showed the most efficient performance in all of the 4G/5G mobile communication networks, Chrome, and Edge browsers. In the case of STL and OBJ, the traffic was relatively excessive in 5G NR and Edge browsers. The findings of this study are expected to be utilized to develop a 3D file format that reduces the loading time in a mobile web environment.

• Journal of Broadcast Engineering
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• v.22 no.4
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• pp.473-483
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• 2017

Since the advent of 3D and UHD contents, demand for high-quality panoramic images has been increasing. The UWV(Ultra-Wide Viewing) service uses a wider viewing angle than conventional panoramas to provide a lively experience for users and enhance their understanding of the event. In this paper, we propose a spatial adjacency map generation method and an UWV file storage format technology to provide UWV service. The spatial adjacency map measures the similarity between images and generate the position information of the images based on similarity. And the stitching time of the image can be shortened through the generated position information. Through the spatial adjacency map, we generate the large screen content quickly. The UWV file format which is based on ISOBMFF process spatial adjacency map and videos and support random access. In this paper, we design the UWV player to verify the spatial adjacency map and UWV file format and show the result of experiments.

• Korean Journal of Computational Design and Engineering
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• v.7 no.2
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• pp.89-95
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• 2002

VRML data, which is mainly structural element, is frequently used for modeling and visualizing 3D objects. Although there can be variations, it is a usual practice to represent 3D shapes in VRML format. Ever since the advent of Internet, there have been strong needs to transfer shape data through Internet. Because of this need, it is necessary to transform a data file in VRML or similar format into a more convenient form to transfer through the network. In a VRML file, a model is sometimes divided into a set of triangle meshes due to several practical reasons. However, this causes various demerits for the fast transmission. Therefore, it is more efficient to merge the mesh sets into one mesh set for the transmission. In this paper, we present the problems in the merge process and the techniques to handle the situation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.416-421
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• 1997

This study presents a way to construct 3D shape in STL format from 2D slice data. Nowadays ahape reconstruct has been done in many ares, the application of this method is important especially in Reverse Engineering which reconstructs original shape from cross-section data. Current RP (Rapid Prototyping) is used not only for the verification of a part designed but also for the production and tooling in more effective way. In RP technology, data should be prepared in STL format. In this paper, the way to make 3D shape data in STL format form 2D slice data is described which can be used to reconstruct an original shape in RP equipment.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.1
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• pp.68-74
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• 2000

The STL file format is an approximation of 3-D model with triangular facets. STL is a standard input file format of Rapid Prototyping(RP) equipment In computer graphics a circle has been approximated with an inscribed polygon which causes an error between the real and approximated circles. In this study an intersecting polygon has been used to approximate the circle and applied to produce more accurate RP part. The newly proposed method shows it's excellence in part accuracy.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.75-79
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• 1999

Geo-features play a key role in object-oriented or feature-based geo-processing system. So the strategy for how-to-model and how-to-manage the geo-features builds the main architecture of the entire system and also supports the efficiency and functionality of the system. Unlike the conventional 2D geo-processing system, geo-features in 3B GIS have lots to be considered to model regarding the efficient manipulation and analysis and visualization. When the system is running on the Web, it should also be considered that how to leverage the level of detail and the level of automation of modeling in addition to the support for client side data interoperability. We built a set of 3D geo-features, and each geo-feature contains a set of aspatial data and 3D geo-primitives. The 3D geo-primitives contain the fundamental modeling data such as the height of building and the burial depth of gas pipeline. We separated the additional modeling data on the geometry and appearance of the model from the fundamental modeling data to make the table in database more concise and to allow the users more freedom to represent the geo-object. To get the users to build and exchange their own data, we devised a file format called VGFF 2.0 which stands for Virtual GIS File Format. It is to describe the three dimensional geo-information in XML(eXtensible Markup Language). The DTD(Document Type Definition) of VGFF 2.0 is parsed using the DOM(Document Object Model). We also developed the authoring tools for. users can make their own 3D geo-features and model and save the data to VGFF 2.0 format. We are now expecting the VGFF 2.0 evolve to the 3D version of SVG(Scalable Vector Graphics) especially for 3D GIS on the Web.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.10
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• pp.1748-1753
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• 2003

This paper describes the forming of fine gear housing using RP system. In order to apply 3D model formed through CAD software to RP system, it is necessary of transforming 3D model into STL file format. Besides, when the same shape is formed repetitively, we must solve the program that the shape accuracy of prototype is irregular. Therefore, we will make an experiment on influence of 3D model, file transformation and prototype on facetres, AutoCAD system value. On the basis of experimental result, we will develop an automatic file transformation program for RP. In the final process, we will manufacture on a better prototype according to the experiment result of fine gear housing.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.87-93
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• 2013

In this research, a new methodology to perform building energy analysis using Industry Foundation Classes (IFC) standard has been studied. With the help of Archicad 14 modeling software, a 3D test model is generated and then exported to IFCXML format. A ruby code program retrieves the building information from the resulting IFCXML file using Nokogiri library. An INP file is created and gets ready for next energy analysis step. DOE 2.2 program analyzes the INP file and gives a detailed report of the energy cost of the building. Case study shows when using the IFC standard method, the Interoperability of the energy analysis is greatly improved. The main stream 3D building modeling software supports IFC standard. DOE 2.2 is able to read the INP file generated by IFC file. This means almost any 3D model created by main stream modeling software can be analyze in terms of energy cost Thus, IFC based energy analysis method has a promising future. With the development and application of IFC standard, designers can do more complex and easy-to-run energy analysis in a more efficient way.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.542-551
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• 2011

Recently an extension to DMB-AF (Digital Multimedia Broadcasting Application Format) standard was proposed in [1] without sufficient validation for industrial application due to incomplete implementation. The extended DMB-AF can include stereoscopic video and stereoscopic images for interactive service data, i.e., MPEG-4 BIFS data, in addition to the existing 2D video and 2D images for BIFS services. The contents in the extended DMB-AF can provide a temporal mixture of 2D/3D video presentations possibly with or without 2D/3D images for BIFS services. In this paper we developed DMB-AF player software that can play the extended DMB-AF files and authored several test files for its verification. As a result, we introduced a new method for indicating dependencies of 3D media tracks to improve the extension in [1] and validated the extended DMB-AF with the improvement.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.6
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• pp.243-250
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• 2021

With the increased development of 3D VR applications augmented by recent VR/AR/MR technologies and by the advance of 3D devices, interchangeability and portability of 3D data have become essential. 3D files should be processed in a standard data format for common usage between applications. Providing standardized libraries and data structures along with the standard file format means that a more efficient system organization is possible and unnecessary processing due to the usage of different file formats and data structures depending on the applications can be omitted. In order to provide the function of using a common data file and data structure, this research is intended to provide a programming binding tool for generating and storing standardized data so that various services can be developed by accessing the common 3D files. To achieve this, this paper defines a common data structure including classes and functions to access X3D files with a standardized scheme using the Python programming language. It describes the implementation of a Python language binding viewer, which is an X3D VR viewer for rendering standard X3D data files based on the language binding interface. The VR viewer includes Python based 3D scene libraries and a data structure for creation, modification, exchange, and transfer of X3D objects. In addition, the viewer displays X3D objects and processes events using the libraries and data structure.