• Spatial Information Research
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• v.13 no.2 s.33
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• pp.119-128
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• 2005

Most spatial data handled in GIS is two-dimensional. These two-dimensional data is established by selecting 2D aspects form 3D, or by projecting 3D onto 2D space. During this conversion, without user's intention, data are abstracted and omitted. This unwanted data loss causes disadvantages such as restrictingof the range of data application and describing inaccurate real world. Recently, three dimensional data is getting wide interests and demands. One of the examplesis Database Management System which can store and manage three dimensional spatial data. However, this DBMS does not support spatial query which is the essence of the database management system. So, various studies are needed in this field. This research designs spatial relationship that is defined in space database standard using the three-dimension space model. The spatial data model, which is used in this research, is the one defined in OGC for GMS3, and designing tool is DE-9IM based on Point-Set Topology blow as the best method for topological operation.

• Journal of Korea Multimedia Society
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• v.20 no.12
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• pp.2009-2015
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• 2017

A two-dimensional lens is required to reproduce both the horizontal and vertical parallax through an autostereoscopic 3D display. Among the two-dimensional lenses, a hexagonal micro lens array (MLA) having good optical efficiency is mainly used. However, the hexagonal MLA has complex geometric features. The first feature is that the lens cells are zigzagged in the vertical direction, which should be reflected in the view number calculation for each sub-pixel. The second feature is that the four sides of a hexagonal lens cell are tilted, requiring a more careful view index assignment to the lens cell. In this paper, we propose a sub-pixel multiplexing scheme suitable for the features of the hexagonal MLA. We also propose a view-overlay algorithm based on a two-dimensional lens and compare subjective image quality with existing view-selection through autostereoscopic 3D display implementation.

• Current Optics and Photonics
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• v.1 no.2
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• pp.95-100
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• 2017

The transmittance of the three dimensional (3D) transparent display is an important factor and can be enhanced by adding a see-through area to the displayed 3D image in order to transmit an ambient light with maximum transparency. However, there is a side effect that the perceived 3D resolution can be degraded due to the see-through area. In this paper, we propose an advanced method to resolve the above trade-off relation between the transparency and the 3D resolution by using an active parallax barrier (PB) with a see-through area. The experimental results are also presented to prove the proposed principle.

• Journal of information and communication convergence engineering
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• v.17 no.1
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• pp.60-66
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• 2019

In this paper, we propose a new free-view three-dimensional (3D) computational reconstruction of integral imaging to improve the visual quality of reconstructed 3D images when low-resolution elemental images are used. In a conventional free-view reconstruction, the visual quality of the reconstructed 3D images is insufficient to provide 3D information to applications because of the shift and sum process. In addition, its processing speed is slow. To solve these problems, our proposed method uses a pixel rearrangement technique (PERT) with locally selective elemental images. In general, PERT can reconstruct 3D images with a high visual quality at a fast processing speed. However, PERT cannot provide a free-view reconstruction. Therefore, using our proposed method, free-view reconstructed 3D images with high visual qualities can be generated when low-resolution elemental images are used. To show the feasibility of our proposed method, we applied it to optical experiments.

• Current Applied Physics
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• v.18 no.11
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• pp.1235-1239
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• 2018

We present a novel process to fabricate three-dimensional (3D) metallic patterns from 3D printed polymeric structures utilizing different hygroscopic swelling behavior of two different polymeric materials. 3D patterns are printed with two different polymers as cube shape. The surface of the 3D printed polymeric structures is plated with nickel by an electroless plating method. The nickel patterns on the surface of the 3D printed cube shape structure are formed by removing sacrificial layers using the difference in the rate of hygroscopic swelling between two printing polymer materials. The hygroscopic behavior on the interfaced structure was modeled with COMSOL Multiphysics. The surface and electrical properties of the fabricated three-dimensional patterns were analyzed and characterized.

• The Journal of Engineering Geology
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• v.32 no.1
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• pp.85-99
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• 2022

Rock discontinuities, as weak interfaces in rock, control mechanical properties of rock mass. Presence of discontinuities complicates the engineering properties of rock, which is the root of anisotropy and heterogeneity that have nonnegligible influences on the rock engineering. Morphological characteristics of discontinuities in natural rock are an important factor influencing the mechanical properties, particularly roughness, of discontinuities. Therefore, the accurate measurement and characterization of morphologies of discontinuities are preconditions for studying mechanical properties of discontinuities. Taking discontinuities in red sandstone as research objects, the research obtained three-dimensional (3D) morphologies of discontinuities in natural rock by carrying out 3D morphological scanning tests. The waviness and roughness were separated from 3D morphologies of rock discontinuities through wavelet transform. In addition, the calculation method for the overall slope root mean square (RMS) as well as slope RMSs of waviness and roughness of 3D morphologies of discontinuities considering the shear direction was proposed. The research finally determined an evaluation method for 3D morphologies of discontinuities by quantitatively characterizing 3D morphologies with the mean value of the three slope RMSs.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.1-8
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• 2022

High-density packaging technologies, including Through-Si-Via (TSV) technologies, are considered important in many fields such as IoT (internet of things), 6G/5G (generation) communication, and high-performance computing (HPC). Achieving high integration in two dimensional packaging has confronted with physical limitations, and hence various studies have been performed for the three-dimensional (3D) packaging technologies. In this review, we described about the causes and effects of scallop formation in TSV, the scallop-free etching technique for creating smooth sidewalls, Cu pillar and Cu-SiO₂ hybrid bonding in TSV. These technologies are expected to have effects on the formation of high-quality TSVs and the development of 3D packaging technologies.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.8
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• pp.119-125
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• 2009

Fabrication of a three-dimensional (3D) metallic mold for multi-production of a microstructure was studied to settle the problem of long processing time in 3D microfabrication. To date, complicated 3D microstructures including 3D photonic crystals, 3D microlens array, 3D filter for microfludics, and something else were created successfully using the two-photon polymerization (TPP) which was considered as paving the way to fabricate a real 3D shape in nano/microscale. However, for those fabrications, much processing time and efforts were inevitably required. To solve this issue, a simple and effective way was proposed in this paper; 3D master patterns were prepared using TPP, and then counter-shaped Ni molds were fabricated by electroforming process. By using these molds, 3D microstructures can be reproduced with short-processing time and low-effort comparing to the conventional approach, TPP We report some parameters to fabricate a metallic mold precisely.

• Journal of International Society for Simulation Surgery
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• v.3 no.1
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• pp.36-38
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• 2016

Fibrous dysplasia is a relatively rare disease but the management would be quite challenging. Because this is not a malignant tumor, the preservation of the facial contour and the various functions seems to be important in treatment planning. Until now the facial bone reconstruction with autogenous bone would be the standard. Although the autogenous bone would be the ideal one for facial bone reconstruction, donor site morbidity would be the inevitable problem in many cases. Meanwhile, various types of allogenic and alloplastic materials have been also used. However, facial bone reconstruction with many alloplastic material have produced no less complications including infection, exposure, and delayed wound healing. Because the 3D printing technique evolved so fast that 3D printed titanium implant were possible recently. The aim of this trial is to try to restore the original maxillary anatomy as possible using the 3D printing model, based on the mirrored three dimensional CT images based on the computer simulation. Preoperative computed tomography (CT) data were processed for the patient and a rapid prototyping (RP) model was produced. At the same time, the uninjured side was mirrored and superimposed onto the traumatized side, to create a mirror-image of the RP model. And we molded Titanium mesh to reconstruct three-dimensional maxillary structure during the operation. This prefabricated Titanium-mesh implant was then inserted onto the defected maxilla and fixed. Three dimensional printing technique of titanium material based on the computer simulation turned out to be successful in this patient. Individualized approach for each patient could be an ideal way to restore the facial bone.

• Journal of Korea Game Society
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• v.13 no.3
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• pp.131-140
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• 2013

The study analyzes how to create stereoscopic image in 3-dimension animation 'Yggdrasil', produced in Autodesk Maya(3D animation software), using Anaglyph method that is the oldest in 3-dimension stereoscopic video production. The anaglyph method help to produce stereoscopic images easily and to give effective 3D effect encoding each eye's image using filters of different colors. In addition, space direction applied visual perception theory expresses necessary distance, depth and speed effectively in 'Yggdrasil'