• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.162-172
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• 2014

A three-dimensional dynamic model for simulating various motions of full vehicle is presented. The model has 16 independent degrees of freedom (DOF) consisting of three kinds of components; a vehicle body of 6 DOF, 4 independent suspensions equipped at every corner of the body, and 4 tire models linked with each suspension. The dynamic equations are represented in six coordinate frames such as world fixed coordinate, vehicle fixed coordinate, and four wheel fixed coordinate frames. Then these lead to the approximated prediction model of vehicle posture. Both lateral and longitudinal dynamics can be computed simultaneously under the conditions of which various inputs including steering command, driving torque, gravity, rolling resistance of tire, aerodynamic resistance, etc. are considered. It is shown through simulations that the proposed 3D model can be useful for precise design and performance analysis of any full vehicle control systems.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.597-601
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• 2008

Three-dimensional structures of detonation wave propagating in circular tube were investigated. Inviscid fluid dynamics equations coupled with a conservation equation of reaction progress variable were analyzed by a MUSCL-type TVD scheme and four stage Runge-Kutta time integration. Variable-$\gamma$ formulation was used to account for the variable properties between unburned and burned states and the chemical reaction was modeled by using a simplified one-step irreversible kinetics model. The computational code was parallelized based on domain decomposition technique using MPI-II message passing library. The computations were carried out using a home made Windows based PC cluster having 160 AMD AthloxXP and Athlon64 processor. The computational domain consisted of through a roundshaped tube with wall conditions. As an initial condition, analytical ZND solution was distributed over the computational domain with disturbances. The disturbances has circumferential large gradient. The unsteady computational results in three-dimension show the detailed mechanisms of multi-cell mode of detonation wave instabilities resulting diamond shape in smoked-foil record.

• Journal of Sensor Science and Technology
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• v.28 no.2
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• pp.113-116
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• 2019

A three-dimensional porous structure was fabricated by pattern transfer printing for applications of electrodes in gas sensors. To form replica patterns, solutions were mixed with acetone, toluene, heptane, and poly(methyl methacrylate). These replica patterns can also be formed on substrates such as polyimide, polydimethylsiloxane, and silicon. The wide range of line widths from 1 to $5{\mu}m$ was derived from the surface grating patterns of master substrates. The cross-bar pattern with 40 layers showed a thickness of 600 nm. The area of platinum transferred patterns with different line widths was enhanced to $20{\times}25mm$, which is applicable to various electrode patterns of gas sensors.

• Journal of Multimedia Information System
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• v.9 no.3
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• pp.183-190
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• 2022

Image-based 3D object detection is one of the important and difficult problems in autonomous driving and robotics, and aims to find and represent the location, dimension and orientation of the object of interest. It generates three dimensional (3D) bounding boxes with only 2D images obtained from cameras, so there is no need for devices that provide accurate depth information such as LiDAR or Radar. Image-based methods can be divided into three main categories: monocular, stereo, and multi-view 3D object detection. In this paper, we investigate the recent state-of-the-art models of the above three categories. In the multi-view 3D object detection, which appeared together with the release of the new benchmark datasets, NuScenes and Waymo, we discuss the differences from the existing monocular and stereo methods. Also, we analyze their performance and discuss the advantages and disadvantages of them. Finally, we conclude the remaining challenges and a future direction in this field.

• Kyungpook Mathematical Journal
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• v.62 no.4
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• pp.715-728
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• 2022

The aim of this article is to study the h-almost Ricci solitons and h-almost gradient Ricci solitons on generalized Sasakian-space-forms. First, we consider h-almost Ricci soliton with the potential vector field V as a contact vector field on generalized Sasakian-space-form of dimension greater than three. Next, we study h-almost gradient Ricci solitons on a three-dimensional quasi-Sasakian generalized Sasakian-space-form. In both the cases, several interesting results are obtained.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.330-331
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• 2020

In this paper, we propose a new three-dimension space vector pulse width modulation for three-phase four-wire inverter under line-to-line fault. In order to this method, the processes of selecting of the output voltage vectors and synthesizing the reference voltage vector are discussed. In addition, we deal with the calculation of the duty cycles for each sector. The experiments are provided to validate the effectiveness of the proposed method.

• Korean Journal of Remote Sensing
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• v.30 no.1
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• pp.149-160
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• 2014

Recently studies on application development and utilization using sensors and devices embedded in smartphones have flourished at home and abroad. This study aimed to analyze the accuracy of the images of smartphone to determine three-dimension position of close objects prior to the development of photogrammetric system applying smartphone and evaluate the feasibility to use. First of all, camera calibration was conducted on autofocus and infinite focus. Regarding camera calibration distortion model with balance system and unbalance system was used for the decision of lens distortion coefficient, the results of calibration on 16 types of projects showed that all cases were in RMS error by less than 1 mm from bundle adjustment. Also in terms of autofocus and infinite focus on S and S2 model, the pattern of distorted curve was almost the same, so it could be judged that change in distortion pattern according to focus mode is very little. The result comparison according to autofocus and infinite focus and the result comparison according to a software used for multi-image processing showed that all cases were in standard deviation less than ${\pm}3$ mm. It is judged that there is little result difference between focus mode and determination of three-dimension position by distortion model. Lastly the checkpoint performance by total station was fixed as most probable value and the checkpoint performance determined by each project was fixed as observed value to calculate statistics on residual of individual methods. The result showed that all projects had relatively large errors in the direction of Y, the direction of object distance compared to the direction of X and Z. Like above, in terms of accuracy for determination of three-dimension position for a close object, the feasibility to use smartphone camera would be enough.

• Journal of the Korea Fashion and Costume Design Association
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• v.14 no.3
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• pp.37-49
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• 2012

The purpose of this study is to provide basic data of dress design by researching three-dimensional decorative techniques representing flowers, a popular motif in dress design. This study analyzed 44 dresses that were presented in Valentino collection. The result of this study is as follows: First, the detailing expression method can show various patterns and colors through embroidery technique, sub-materials, and bonding techniques in embroidery, beads flower, and ribbon flowers. Second, the fabric flower technique expressed flower image in three-dimension in more various images than do either the ribbon or beads flower technique. Fabric flowers are mostly made from the same material as dresses. The expression technique of fabric flower is classified into the following three classifications: 1) A technique underlying a flower image with one, two and three large flowers, 2) a technique decorating a large area with a number of an identical motif, and 3) a technique highlighting a part of the body or design line by attracting eyes to one point, creating a corsage decorated where a designer wants to emphasize. Third, a silhouette technique realizes a flower image with a silhouette of a dress like sculpted structure and it is thus used less than a detailing expression technique. A flower image is expressed by making use of body lines or emphasizing the face. Finally, flower images on a dress were realized as a full blossomed flower, through visually streamlined shapes and curved lines.

• Journal of Biosystems Engineering
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• v.17 no.1
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• pp.37-44
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• 1992

This study was intended to develop the design program of the working surface of moldboard-plow by use of the computer-aided design. The mathematical model of the working surfaces of moldboard-plows by use of computer graphics was developed and plotted in two dimension on three major planes. The surfaces of moldboard-plows were represented with "B-spline surface fitting" by selecting the twenty-five three-dimensional data that could well describe the working surface of moldboard-plow. The shape of moldboard-plow on three major planes was drawn for varied design parameters. The representation of the mathematical model for the working surfaces of various types of moldboard-plows was manipulated by translation, rotation and scaling about arbitrary axes in space. By using three-dimensional graphics techique to describe moldboard-plows, it was capable of plotting the three-dimensional shape of moldboard-plow easily and quickly in comparison with the existing design methods that were difficult to grasp the shape of moldboard-plow as a whole. The design theories of moldboard plow and three-dimensional computer graphic technique were applied to find out the improved reversible Jaenggi bottom. It was resulted in the newly developed shape of Jaenggi which may be used for improving the performance compared to existing ones.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1697-1704
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• 2018

As a key component of lighting location system (LLS) for lightning warning, the atmospheric electric field measuring is required to have high accuracy. The Conventional methods of the existent electric field measurement meter can only detect the vertical component of the atmospheric electric field, which cannot acquire the realistic electric field in the thunderstorm. This paper proposed a three dimensional (3D) electric field system for atmospheric electric field measurement, which is capable of three orthogonal directions in X, Y, Z, measuring. By analyzing the relationship between the electric field and the relative permittivity of ground surface, the permittivity is calculated, and an efficiency 3D measurement model is derived. On this basis, a three-dimensional electric field sensor and a permittivity sensor are adopted to detect the spatial electric field. Moreover, the elevation and azimuth of the detected target are calculated, which reveal the location information of the target. Experimental results show that the proposed 3D electric field meter has satisfactory sensitivity to the three components of electric field. Additionally, several observation results in the fair and thunderstorm weather have been presented.