• Journal of Institute of Control, Robotics and Systems
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• v.8 no.5
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• pp.419-424
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• 2002

After the patterning and probe process of wafer have been achieved, the dicing processing is necessary to separate chips from a wafer. The dicing process cuts a semiconductor wafer to lengthwise and crosswise directions to make many chips. The existing general dicing method is the mechanical cutting using a narrow circular rotating blade impregnated diamond particles or laser cutting. Inferior goods can be made by the mechanical or laser cutting unless several parameters such as blade, wafer, cutting water and cutting conditions are properly set. Moreover, we can not apply these general dicing method to that of GaN wafer, because the GaN wafer is harder than general semiconductor wafers such as GaAs, GaAsP, AIGaAs and so forth. In order to overcome these problems, this paper describes a new wafer dicing method using fixed diamond scriber and precision servo mechanism.

• Korean Journal of Applied Biomechanics
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• v.27 no.1
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• pp.67-74
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• 2017

Objective: The purpose of this study was to apply a general linear model in statistics to marker position vectors used to study human joint rotational motion in biomechanics. Method: For this purpose, a linear model that represents the effect of the center of hip joint rotation and the rotation of the marker position on the response was formulated. Five male subjects performed hip joint functional motions, and the positions of nine markers attached on the thigh with respect to the pelvic coordinate system were acquired at the same time. With the nine marker positions, the center of hip joint rotation and marker positions on the thigh were estimated as parameters in the general linear model. Results: After examining the fitted model, this model did not fit the data appropriately. Conclusion: A refined model is required to take into account specific characteristics of longitudinal data and other covariates such as soft tissue artefacts.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.18 no.4
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• pp.317-335
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• 2014

In this work, we investigate the global stability analysis of a viral infection model with antibody immune response. The incidence rate is given by a general function of the populations of the uninfected target cells, infected cells and free viruses. The model has been incorporated with two types of intracellular distributed time delays to describe the time required for viral contacting an uninfected cell and releasing new infectious viruses. We have established a set of conditions on the general incidence rate function and determined two threshold parameters $R_0$ (the basic infection reproduction number) and $R_1$ (the antibody immune response activation number) which are sufficient to determine the global dynamics of the model. The global asymptotic stability of the equilibria of the model has been proven by using Lyapunov theory and applying LaSalle's invariance principle.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.10 s.241
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• pp.1321-1328
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• 2005

Based upon the Floquet theory, the complex modal solution for general rotor systems with periodically time-varying parameters is newly derived. The complete modal response can be obtained from the orthonormality condition between the time-variant eigenvectors and the corresponding adjoint vectors. The harmonic solutions such as the response and directional special a patterns are then derived in terms of harmonic modes whose coefficients are obtained from the modal analysis. The stability analysis by the Floquet's transition matrix and the eigen-analysis is also performed.

• Journal of Applied Reliability
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• v.11 no.3
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• pp.267-279
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• 2011

LEDs have been used extensively in the mobile device, automobile, and general lighting because they are semi-permanent, long life, less power consumption, reliable and environmentally friendly. In this paper, the accelerated degradation test(ADT) for a general lighting 4W LED Lamp using external converter is considered. The conditions of ADT are high temperature and high humidity. We show that its life time is log-normally distributed with same parameters under both a normal condition and an accelerated condition, and also derive an accelerated factor.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.83-83
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• 2004

The analysis of relative pose(position and rotation) between stereo cameras is very important to determine the solution that provides three-dimensional information for an arbitrary moving target with respect to robot-end. In the space of free camera-model, the rotational parameters act on non-linear factors acquiring a kinematical solution. In this paper the general solution of active stereo that gives a three-dimensional pose of moving object is presented. The focus is to achieve a derivation of linear equation between a robot′s end and active stereo cameras. The equation is consistently derived from the vector of quaternion space. The calibration of cameras is also derived in this space. Computer simulation and the results of error-sensitivity demonstrate the successful operation of the solution. The suggested solution can also be applied to the more complex real time tracking and quite general and are applicable in various stereo fields.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.89-90
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• 2004

The analysis of relative pose(position and rotation) between stereo cameras is very important to determine the solution that provides three-dimensional information for an arbitrary moving target with respect to robot-end. In the space of free camera-model, the rotational parameters act on non-linear factors acquiring a kinematical solution. In this paper the general solution of active stereo that gives a three-dimensional pose of moving object is presented. The focus is to achieve a derivation of linear equation between a robot's end and active stereo cameras. The equation is consistently derived from the vector of quaternion space. The calibration of cameras is also derived in this space. Computer simulation and the results of error-sensitivity demonstrate the successful operation of the solution. The suggested solution can also be applied to the more complex real time tracking and quite general and are applicable in various stereo fields.

• Korean Journal of Medicinal Crop Science
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• v.13 no.5
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• pp.242-248
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• 2005

The present study was designed to elucidate the physiological changes with age by chronic administration of red ginseng. All rats were reared in the conventional system. Ginseng treated rats were continously supplied with ginseng water extracts together water from 6 weeks of age to the age 24 months. Rats did not show any discernible signs or the rejection symptoms by red ginseng water extracts. A long-term administration of red ginseng extracts did not cause any physiological changes in the gain of body and organs weight, food intake and general properties of urine. However, red ginseng caused to decrease the level of serum cholesterol, glucose and TBARS, and it attenuated effectively the age-dependent decline of LDH activity. Other biochemical parameters measured from blood and general properties of urine were not significantly changed. These results suggest that long-term administration of red ginseng to rat does not cause any clear physiological changes in appearance and urine, and it retards age-related deteriorations in some biochemical parameters such as LDL-cholesterol, glucose and LDH in serum.

• Journal of Environmental Impact Assessment
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• v.10 no.4
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• pp.319-326
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• 2001

This study is aimed at the development of a comprehensive web-based partial differential equation solver (WPDES) using multidimensional finite element method, which can be operated on the basis of world wide web. Overall issues of engineering and environmental information management and facility control could be implemented using this solver. This paper describes the development technique of the model, which is first part on development of partial differential equation solver. Conventional commercial general solver of computational fluid dynamics problems were investigated. All the relevant environmental models were analyzed to develop integrated environmental management system using WPDES. The governing equations and the parameters of investigated models were analyzed and integrated. Several numerical modules were invented for each partial differential term in partial differential equation of many related modeling problems. Each module was coded in the fashion of object oriented method, and was combined independently for the overall governing equation. WPDES has unique characteristic, which can analyze the problem through the suitable combination of modules without development of additional models for each environment problem with different governing equation, main variables, and parameters.

• The Journal of Korean Physical Therapy
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• v.32 no.3
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• pp.185-190
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• 2020

Purpose: Gait and cognitive impairment in stroke patients exacerbate fall risk and mobility difficulties during multi-task walking. Virtual reality can provide interesting and challenging training in a community setting. This study evaluated the effect of community-based virtual reality gait training (VRGT) using a 360-degree image on the gait ability of chronic stroke patients. Methods: Forty-five chronic stroke patients who were admitted to a rehabilitation hospital participated in this study. Patients meeting the selection criteria were randomly divided into a VRGT group (n=23) and a control group (n=22). Both these groups received general rehabilitation. The VRGT group was evaluated using a 360-degree image that was recorded for 50 minutes a day, 5 days per week for a total of 6 weeks after their training. The control group received general treadmill training for the same amount of time as that of the VRGT group. The improvement in the spatiotemporal parameters of gait was evaluated using a gait analyzer system before and after training. Results: The spatiotemporal gait parameters showed significant improvements in both groups compare with the baseline measurements (p<0.05), and the VRGT group showed more improvement than the control group (p<0.05). Conclusion: Community-based VRGT has been shown to improve the walking ability of chronic stroke patients and is expected to be used in rehabilitation of stroke patients in the future.