• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.172-176
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• 1997

It is likely that the corona discharge appears due to the motion and the multiplication of electron and ion under the nonuniform electric field. Because the motion and the multiplication of electron and ion are the function of electric field, for the simulation of the corona discharge, we have to calculate the electric field, before the calculation of the motion and the multiplication of electron and ion. In this paper, the electric field is calculated on the assumption that the gap between a hyperboloidal needle and a plane is 1-dimension, and the motion and the multiplication of electron and ion are determined by Flux-Corrected Transport method. For this purpose, we solve the electron and ion continuity equation together with Poisson equation. We calculated the current density and the electron and ion density distributions between electrodes as well as electric field distortion due to the space charge assuming that the discharge channel radius is 100${\mu}{\textrm}{m}$. In this simulation, it is found that the current density has one peak as observed by experiment, and electric field distortion is important to the formation and the stability of the corona discharge.

• Mass Spectrometry Letters
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• v.6 no.4
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• pp.91-98
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• 2015

The Brownian motion or Wiener process, as the physical model of the stochastic procedure, is observed as an indexed collection random variables. Stochastic procedure are quite influential on the confinement potential fluctuation in the quadrupole ion trap (QIT). Such effect is investigated for a high fractional mass resolution Δm/m spectrometry. A stochastic procedure like the Wiener or Brownian processes are potentially used in quadrupole ion traps (QIT). Issue examined are the stability diagrams for noise coefficient, η=0.07;0.14;0.28 as well as ion trajectories in real time for noise coefficient, η=0.14. The simulated results have been obtained with a high precision for the resolution of trapped ions. Furthermore, in the lower mass range, the impulse voltage including the stochastic potential can be considered quite suitable for the quadrupole ion trap with a higher mass resolution.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.05a
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• pp.327-332
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• 2002

We made a human-sensitive motion interpretation to the interactive emotional robot, "Rai" of which the mechanism design was carried out and completed. Kinematic system of this emotional robot mainly consists of a body and a head. The body contains the total control units , the communicat ion modules and also two wheels and motors for main driving which make kinds of motions 1 ike the inverted pendulum. This robot system is designed under the concept on the human-friendly mot ion and react ion wi th humans around living room and office environments. Therefore, various scenarios are constructed in order to enable the emotional expressions at those places. Especially, we interpreted technically-possible motions while accommodating to the scenarios constructed. And we performed some experiments to make sere of the possibility of the motion interpretation.

• Journal of Astronomy and Space Sciences
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• v.33 no.3
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• pp.207-210
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• 2016

Under the assumption of the presence of a medium-scale E × B drift vortex of plasma in the daytime midlatitude F region, and using a simplified ionospheric model, we demonstrate that the E × B drift produces noticeable perturbations in the horizontal distribution of the plasma density in the upper F region. The pattern of ion density perturbations shows two separate medium scale domains of enhanced and reduced ion density with respect to the background. The E × B drift does not produce multiple small-scale ion density irregularities through plasma mixing because of the suppression effect of the field-aligned ambipolar plasma diffusion.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.432-432
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• 2000

The above-Knee Prosthesis has been used by the handicapped person and become a important part of their life. But uniform above-knee prosthesis only increases inconvenience And so the tool that can estimate and help to design of suitable prosthesis for user need to be developed. The simulator developed in this research is composed of two part. One is hardware that can realize various walking motions. The other is software that can display and analyze the results of walking mot ion. Three motors constitute hardware of Simulator. Two motors are used to realize heap motion that need two degree of freedom and the rest one used to realize swing motion. Software of Simulator display results of three motor trajectories and walking mot ion of hardware using computer graphic. Therefore, The simulator developed in this research which is able to realize human gait and results are analyzed through simulation program at PC will be some help to design and produce of prosthesis suitable to user.

• Journal of Biomedical Engineering Research
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• v.41 no.1
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• pp.28-34
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• 2020

In this paper, we introduce motion artifact reduction algorithm for interleaved MRI using an advanced 3D approximation algorithm. The motion artifact framework of this paper is data corrected by post-processing with a new 3-D approximation algorithm which uses data structure for each voxel. In this study, we simulate and evaluate our algorithm using Shepp-Logan phantom and T1-MRI template for both scattered dataset and uniform dataset. We generated motion artifact using random generated motion parameters for the interleaved MRI. In simulation, we use image coregistration by SPM12 (https://www.fil.ion.ucl.ac.uk/spm/) to estimate the motion parameters. The motion artifact correction is done with using full dataset with estimated motion parameters, as well as use only one half of the full data which is the case when the half volume is corrupted by severe movement. We evaluate using numerical metrics and visualize error images.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.138-141
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• 2001

영상을 전경과 배경으로 분리하는 작업은 영상을 의미 있고 관심의 대상인 전경 영역과 그렇지 않은 배경 영역으로 나눈다는 점에서 매우 유용한 작업이다. 기존의 제안된 방법으로는 intensity 기반, 깊이 기반 그리고 motion 기반 배경 제거 방법 등이 있다. 본 논문에서는 영상내의 intensity 정보와 깊이 정보를 함께 이용하여 영상 내의 배경을 제거하는 방법을 제안한다. 제안하는 방법은 영상 인식과 강시 시스템 등의 전처리로서 활용될 수 있다.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.459-462
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• 2002

Many active and passive flow control methods have been studied since decades, but there are only few works about flow control methods using ion wind. This paper presents an experimental study on the wake control behind a circular cylinder using ion wind, a bulk motion of neutral molecules driven by locally ionized air of corona discharge. Experiments are done f3r different electrohydrodynamic numbers - the ratio of an electrical body farce to a fluid Inertial force - from 0 to 2 and for the Reynolds number ranging from $4{\times}10^3\;to\;8{\times}10^3$. Pressure distributions over a cylinder surface are measured and flow visualizations are carried out by smoke wire method. Flow visualizations confirm that ion wind affects significantly the wake structure behind a circular cylinder and pressure drag could be dramatically reduced by the superimposing ion wind.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.842-848
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• 2008

In this study, we propose a novel micro-ion engine system. Single plasma source is used for both ion beam source and neutralizing electron source. By changing the electrical connection, either operation can be switched. This micro-ion engine system gives translation motion and attitude control to microspacecraft. The major objective of this study is verification of our concept. Small plasma source of 20 mm diameter was developed. Plasma was sustained by microwave power. Using this plasma source, ion beam extraction and electron emission was successively demonstrated.

• Tribology and Lubricants
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• v.20 no.3
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• pp.145-151
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• 2004

A modified surface layer by ion implantation is very thin (under 1 $\mu\textrm{m}$) but has superior mechanical characteristics. therefore ion implantation has been used successfully as a surface treatment technology to improve the wear, fatigue, and corrosion resistances of materials. MEVVA which is a kind of ion beam apparatus has merits of low cost and is usable to various metals, but occurs a droplet ranging from micron to tens of micron on the implanted surface at ion implantations. wear is a dynamic phenomenon on interacting surfaces with rotative motion. Since wear changes in condition of the surface, we should control to surface. In order to improve a wear resistance of Ti ion implanted 1C-3Cr steel(material for roller in the cold working process), it is essential to investigate the effect of the droplets on the wear characteristics. In this study, we investigate the effect of the droplets on the wear characteristics of 1C-3Cr steel using SEM Tribosystem as in-situ system. Results show that the droplet occurred at ion implantation becomes the cause of severe wear. Therefore, the ion-implanted surface should be removed the droplet to improve wear resistance.