• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.4
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• pp.402-409
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• 1999

Variable structure control law is well known to be a robust control algorithm and evolution strategy is used as an effective search algorithm in optimization problems. In this paper, we propose a variable structure controller with time-varying switching surface. We calculate the maximum value of seitching surface gradient that is of the 3rd order polynomial form. Evolution strategy is used to optimize the parameters of the switching surface gradient. Finally, the proposed method is applied to position tracking control for BLDC motor. Experimental results show that the proposed method is more useful than the conventional variable structure controller.

• The Journal of Korea Robotics Society
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• v.14 no.3
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• pp.186-190
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• 2019

When problems occurred in the unstable and/or extreme terrain environment, formal field-driving robots were unable to provide any other options such as the transformation of the wheel and body structure, and so on. For such reason, this paper proposed a novel type of integrated wheel mechanism that can be operated as a conventional driving wheel mode and hybrid wheel-leg mode in order to be negotiated in an unstable terrain environment. The mechanical effect of the proposed variable wheel mechanism was analyzed considering the geometric constraint and power requirement of the actuator for the transformation. In addition, we designed and manufactured the prototype of field-driving robot, which reliably control the variable wheel shape. Finally, the effectiveness of the variable wheel mechanism was verified by preliminary experimental approach.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.5
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• pp.417-424
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• 2022

This study proposes a current-balancing technique for an interleaved buck converter using a variable inductor and a snubber capacitor. The proposed scheme balances the inductor current by using the variable inductor and enables zero voltage switching under all load ranges. With the variable inductor, the ripple of inductor current changes according to load variation. In addition, a 1.6 kW prototype is built to verify the validity of the proposed scheme, and the experimental results are successfully obtained.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.209-225
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• 1999

Detailed description of the crystal growth methods permitting one to obtain complicated shape crystals from the melt is given. The variable shaping technique provides the growth of crystals with a discrete altering cross-section configuration during crystallization. The dynamic local shaping technique enables one to grow items with a continuous alteration of the side surface profile by a preset program.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.4
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• pp.417-423
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• 1999

Detailed description of the crystal growth methods permitting one to obtain complicated shape crystals from the melt is given. The variable shaping technique provides the growth of crystals with a discrete altering cross-section configuration during crystallization. The dynamic local shaping technique enables one to grow items with a continuous alteration of the side surface profile by a preset program.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.301-301
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• 2000

It is well known, for many years, that deep drawability ,can be improved by applying variable blank holding force. To apply variable blank holding force during cup during, we set up pressure controlling system on experimental hydraulic press, and the pressure control system is often called NC(Numerically Controlled} cushion system. Using the NC cushion system we carry out pressure control experiment and the proposed structure shows good performance. And we compare drawability of square steel cups with NC cushion and that with conventional cushion. The results show drawability is greatly improved when the pressure control curve is designed in a S-shaped curve. This paper includes design details of the NC cushion system and experimental analysis of drawability with experimental NC cushion system.

• Journal of the Korean Institute of Landscape Architecture
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• v.25 no.2
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• pp.94-103
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• 1997

The purpose of this study is to find out the effects of brick paved under-surface soil physical properties which are changed by fixed trampling. Thus, a sandy loam which is known as a profitable soil for plants is used an experimental soil to study the changes of the soil physical properties. It is related to sand bed's thickness & particle size which are settled by experimental variable factors. According to the variation of sand bed's particle size, bulk density and soil hardness at natural dryed soilcondition result in 0.075~2.00mm>2.00~5.00mm>2.00~8.00mm>5.00~8.00mm, and water content at natural dryed soil condition are observed being insensible change rate from the point that sand thickness is 30~40mm and more sand bed's thickness constructed by the variation of sand bed's thickness.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.6
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• pp.114-120
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• 1997

To assess the validity of the previously computed finite element analysis results, the photoelastic experiment was carried out to determine stress intensity factors for crack originating from thin section of integrally stiffened plates having discontinuous thickness interface. The stress intensity factors were deter- mined by using linear slope method of photoelastic data. Results are presented as variable thickness geometry factor. $F_{IV}$ , for various crack lengths and thickness ratios. The experimental values of F/ sub IV/are compared with 3-D finite element analysis results. The correlation between experimental values and analysis results is resonably good.

• Journal of the Korean Society of Costume
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• v.22
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• pp.333-344
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• 1994

In this study an experiment was made using the function of computer simulation os to whether the phenomenon of optical illusion takes place also in clothing on the human body three-dimensional space through the case study of the Gestalt illusion of planar con-traction and expension by amodal completion in perceptual organization. One woman of latter 30s was selected as the experimental subject. She was made to wear the experimental clothing and then the frontal picture was projected of in the experimental clothing which was scanned into the com-puter. For the sake of the contractive experiment 5 stages were divided by 5-15cm the thick-nes of the black vertical line in the center of the upper garmet as the variable and for the sake of the expansive experiment the skirt length was set as the variable. It length measured 50-90cm which was divided by 10cm into 5 stages and simulated using the CAD. The basic design and the experimental de-sign were made one pair and the pictures totalled 20 pictures such as ten pictures save the human body for the estimation of the up-per garmet alone and ten pictures for the ob-servation of the effect on the human body. The extimating panel consisting of 20 panellers estimated contraction/expansion in the estimation of the upper garmet and the tall effect/the slim effect in the estimation of optical illusion as the estimating factors on the 9-point scale. All the date from experiment were analyzed by ANOVA(analysis of variance) and DUNCAN'S multiple range. As a result the experimental designs all showed a significant optical illusion in comparision with the basic design.

• Journal of the Korea Society of Computer and Information
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• v.21 no.8
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• pp.85-94
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• 2016

The purpose of this research is to clarify the effect that group art therapy with ceramics affects aggression and impulse for juvenile delinquent. The experimental domain of this study was implemented with 24 juvenile delinquent suspended from protective dispositions for them who were in long-term juvenile sheltered housing about for 12 years. These subjects were selected from among juvenile delinquent between 14 to 20 years age who were entrusted from court to the Juvenile Protection Education Institute located in G area. 12 people were randomly assigned each experimental domain and control domain; experimental group was implemented group art therapy with ceramics whereas there was anything to control group. The program was designed once a week and 90minutes each 12 sessions. The result of this study show that control group at variable related aggression was not significantly changed at posttest. In case of experimental group, here was significantly changed as a whole, also sub factor such as physical aggression showed considerable change so that the first hypothesis was supported In addition, experimental group showed the considerable change at sub factor of motor impulsiveness so that the second hypothesis was supported whereas control group at impulse variable was not significantly changed during pretest and posttest. This study results conclude that the juvenile delinquent participating group art therapy with ceramics represents the effect on reduction of aggression and motor impulsiveness. We expect this result will be used as further base line data for juvenile delinquent.