• Journal of the Korean Society of Visualization
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• v.1 no.2
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• pp.58-70
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• 2003

Meteorological data contains observation and numerical weather prediction model output data. The computerized analysis and visualization of meteorological data often requires very high computing capability due to the large size and complex structure of the data. Because the meteorological data is frequently formed in multi-variables, 3-dimensional and time-series form, it is very important to visualize and analyze the data in 3D spatial domain in order to get more understanding about the meteorological phenomena. In this research, we developed interactive 3-dimensional visualization techniques for visualizing meteorological data on a PC environment such as volume rendering, iso-surface rendering or stream line. The visualization techniques developed in this research are expected to be effectively used as basic technologies not only for deeper understanding and more exact prediction about meteorological environments but also for scientific and spatial data visualization research in any field from which three dimensional data comes out such as oceanography, earth science, and aeronautical engineering.

• 한국가시화정보학회:학술대회논문집
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• 2002.11a
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• pp.77-80
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• 2002

The recent 3D visualization such as volume rendering, iso-surface rendering or stream line visualization gives more understanding about structures or distribution of data in a space and, moreover, the real-time rendering of a scene enables the animation of time-series data. Because the meteorological data is frequently formed as multi-variables, 3-dimensional and time-series data, the spatial analysis, time-series analysis, vector display, and animation techniques can do important roles to get more understanding about data. In this research, our aim is to develop the 3-dimensional visualization techniques for meteorological data in the PC environment by using IDL. The visualization technology from :his research will be used as basic technology not only for the deeper understanding and the more exact prediction about meteorological environments but also for the scientific and spatial data visualization research in any field from which three-dimensional data comes out such as oceanography, earth science, or aeronautical engineering.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.257-263
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• 2006

Nowadays, 3-D(Three-dimensions) is used in various field such as Games, Movies, Animations etc. Especially the Role of 3-D computer graphic is being generalized by turnover of Screen from '2-dimensional' to '3-dimensional'. There are not enough data about 'Motion Capture' even though it plays main function in 3-dimensional movement. 'Motion Capture' could be also unfamiliar for people. And as a matter of fact, the use of this equipment is limited due to its high cost. Therefore, I studied the outline of Digital Motion Capture system and its application to 3-D game Character Animation. And I checked the movement of 3-D Character after transplanting the Motion Data to the 3-D Character. I acquired Motion Data by Optical Motion Capture Equipment which we possess and transplanted it into the 3-D Character then Implemented it as walking, running and hitting which are the basic motions of Expression.

• Journal of information and communication convergence engineering
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• v.12 no.3
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• pp.186-192
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• 2014

Monolithic three-dimensional integrated chips (3D ICs) are an emerging technology that offers an integration density that is some orders of magnitude higher than the conventional through-silicon-via (TSV)-based 3D ICs. This is due to a sequential integration process that enables extremely small monolithic inter-tier vias (MIVs). For a monolithic 3D memory, we first explore the static random-access memory (SRAM) design. Next, for digital logic, we explore several design styles. The first is transistor-level, which is a design style unique to monolithic 3D ICs that are enabled by the ultra-high-density of MIVs. We also explore gate-level and block-level design styles, which are available for TSV-based 3D ICs. For each of these design styles, we present techniques to obtain the graphic database system (GDS) layouts, and perform a signoff-quality performance and power analysis. We also discuss various challenges facing monolithic 3D ICs, such as achieving 50% footprint reduction over two-dimensional (2D) ICs, routing congestion, power delivery network design, and thermal issues. Finally, we present design techniques to overcome these challenges.

• Korean Journal of Radiology
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• v.22 no.3
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• pp.435-441
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• 2021

Objective: To evaluate the usefulness of the ventricular volume percentage quantified using three-dimensional (3D) brain computed tomography (CT) data for interpreting serial changes in hydrocephalus. Materials and Methods: Intracranial and ventricular volumes were quantified using the semiautomatic 3D threshold-based segmentation approach for 113 brain CT examinations (age at brain CT examination ≤ 18 years) in 38 patients with hydrocephalus. Changes in ventricular volume percentage were calculated using 75 serial brain CT pairs (time interval 173.6 ± 234.9 days) and compared with the conventional assessment of changes in hydrocephalus (increased, unchanged, or decreased). A cut-off value for the diagnosis of no change in hydrocephalus was calculated using receiver operating characteristic curve analysis. The reproducibility of the volumetric measurements was assessed using the intraclass correlation coefficient on a subset of 20 brain CT examinations. Results: Mean intracranial volume, ventricular volume, and ventricular volume percentage were 1284.6 ± 297.1 cm³, 249.0 ± 150.8 cm³, and 19.9 ± 12.8%, respectively. The volumetric measurements were highly reproducible (intraclass correlation coefficient = 1.0). Serial changes (0.8 ± 0.6%) in ventricular volume percentage in the unchanged group (n = 28) were significantly smaller than those in the increased and decreased groups (6.8 ± 4.3% and 5.6 ± 4.2%, respectively; p = 0.001 and p < 0.001, respectively; n = 11 and n = 36, respectively). The ventricular volume percentage was an excellent parameter for evaluating the degree of hydrocephalus (area under the receiver operating characteristic curve = 0.975; 95% confidence interval, 0.948-1.000; p < 0.001). With a cut-off value of 2.4%, the diagnosis of unchanged hydrocephalus could be made with 83.0% sensitivity and 100.0% specificity. Conclusion: The ventricular volume percentage quantified using 3D brain CT data is useful for interpreting serial changes in hydrocephalus.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.203-208
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• 2007

Due to the long tectonic history and the very complex geologic formations in Korea, the anisotropic characteristics of subsurface material may often change very greatly and locally. The algorithms for the travel time computation commonly used, however, may not give sufficiently precise results particularly for the complex and strong anisotropic model, since they are based on the two-dimensional (2D) earth and/or weak anisotropy assumptions. This study is intended to develope a three-dimensional (3D) modeling algorithm to precisely calculate the first arrival time in the complex anisotropic media. We assume 3D TTI (tilted transversely isotropy) medium having the arbitrary symmetry axis. The algorithm includes the 2D non-linear interpolation scheme to calculate the traveltimes inside the grid and the 3D traveltime mapping to fill the 3D model with first arrival times. The weak anisotropy assumption, moreover, can be overcome through devising a numerical approach of the steepest descent method in the calculation of minimum traveltime, instead of using approximate solution.

• Journal of Broadcast Engineering
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• v.24 no.5
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• pp.765-774
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• 2019

In this paper, we propose a point cloud matching algorithm for multiple RGB-D cameras. In general, computer vision is concerned with the problem of precisely estimating camera position. Existing 3D model generation methods require a large number of cameras or expensive 3D cameras. In addition, the conventional method of obtaining the camera external parameters through the two-dimensional image has a large estimation error. In this paper, we propose a method to obtain coordinate transformation parameters with an error within a valid range by using depth image and function optimization method to generate omni-directional three-dimensional model using 8 low-cost RGB-D cameras.

• Journal of Technologic Dentistry
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• v.42 no.1
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• pp.35-41
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• 2020

Purpose: The purpose of this study was to evaluate the accuracy of the DLP 3D printer by conducting 3-dimensional assesment of resin provisional restorations. Methods: The first premolar of the maxillary was prepared for the abutment. The abutment was scanned by using a scanner. The provisional restoration was designed by using CAD software. A total of 16 resin provisional restorations were produced using ZD200 and Veltz DLP 3D printer. Scanning was done of resin provisional restorations and 3-dimensional measurement was conducted for accuracy. The mean (SD) of RMS was reported for each group. Independent t-test was used to assess the statistical significance of the results. All analyses were done using SPSS 22.0. Results: The mean ± SD of RMS value for the accuracy of the resin provisional restorations that was fabricated by using ZD200 and Veltz DLP 3D printer were 50.85.±4.64㎛ and 70.33±6.31㎛. Independent t-test showed significant differences between groups(p<0.001). Conclusion: The resin provisional restorations made with DLP 3D printers showed clinically acceptable accuracy.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.3
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• pp.230-237
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• 2020

In order to design a diesel engine system and predict its performance, it is necessary to analyze the gas flow of the intake and exhaust system. A gas flow analysis in three-dimensional (3D) format needs a high-resolution workstation and enormous time for analysis. Therefore, the method of characteristics (MOC) was used for a gas flow analysis with a fast calculation time and a low-resolution workstation. An experiment was conducted on a single cylinder diesel engine to measure pressure in cylinder, intake pipe and exhaust pipe. The one-dimensional (1D) gas flow was analyzed under the same conditions as the experiment. The engine speed, valve timing and compression ratio were the same conditions and the intake pressure was inputted as the experimental results. Bent pipe such as an exhaust port that cannot be realized in 1D was omitted. As results of validation, the cylinder pressure showed accuracy, but the exhaust pipe pressure exhibited inaccuracy. This is considered as an error caused by the failure to implement a bent pipe such as an exhaust port. When analyzed in 3D, calculation time required 61 hours more based on a model of this study. In the future, we intend to implement a bent pipe that cannot be realized in 1D using 3D and prepare a method to supplement reliability by using 1D-3D coupling.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.7
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• pp.634-640
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• 2015

This paper proposes a novel three-dimensional mapping algorithm in Omni-Directional Vision SLAM based on a fisheye image and laser scanner data. The performance of SLAM has been improved by various estimation methods, sensors with multiple functions, or sensor fusion. Conventional 3D SLAM approaches which mainly employed RGB-D cameras to obtain depth information are not suitable for mobile robot applications because RGB-D camera system with multiple cameras have a greater size and slow processing time for the calculation of the depth information for omni-directional images. In this paper, we used a fisheye camera installed facing downwards and a two-dimensional laser scanner separate from the camera at a constant distance. We calculated fusion points from the plane coordinates of obstacles obtained by the information of the two-dimensional laser scanner and the outline of obstacles obtained by the omni-directional image sensor that can acquire surround view at the same time. The effectiveness of the proposed method is confirmed through comparison between maps obtained using the proposed algorithm and real maps.