• The Journal of the Acoustical Society of Korea
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• v.39 no.5
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• pp.424-434
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• 2020

This paper describes an algorithm that calculates Absolute Sound Level (ASL) for contents platform. ASL is a single volume representing individual sound sources and is a concept designed to integrate and utilize the sound level units in digital sound source and physical domain from a speaker in practical areas. For this concept to be used in content platforms and others, it is necessary to automatically derive the ASL without having to go through a hearing of mastering engineers. The key parameters of which a person recognizes the representative sound level of an individual single sound source are the areas of "frequency, maximum energy, energy variation coefficient, and perceived energy distribution," and the ASL was calculated through the normalizing of the weights.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.4
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• pp.68-78
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• 2008

For a smooth transition between consecutive paths, conventional robot controllers usually generate a transition trajectory by blending consecutive paths in a time coordinate. However, this has two inherent drawbacks: the shape of a transition path cannot be designed coherently and the speed during transition is uncontrollable. To overcome these problems, this paper provides a path-level, rather than trajectory-level, smooth transition method with the curvature bound between non-smoothly connected paths. The experiment results show that the resultant transition trajectory is more smoothly connected than the conventional methods and the curvature is closely limited to the desired bound within the guaranteed level ($0.02{\sim}1$).

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.297-298
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• 2007

Repetitive systems stand for a kind of systems that perform a simple task on a fixed pattern repetitively and are widely spread in industrial fields. Hence, those systems have been of much interests by many researchers, especially in the field of iterative learning control (ILC). In this paper, we propose a finite-horizon tracking control scheme for linear time-varying repetitive systems with uncertain initial conditions. The scheme is derived both analytically and numerically for state-feedback systems and only numerically for output-feedback systems. Then, it is extended to stable systems with input constraints. All numerical schemes are developed in the forms of linear matrix inequalities. A distinguished feature of the proposed scheme from the existing iterative learning control is that the scheme guarantees the tracking performance exactly even under uncertain initial conditions. The simulation results demonstrate the good performance of the proposed scheme.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.155-156
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• 2007

This paper presents the vision-based camber and optimal cutting line detection algorithm for hot-rolling process. It is important to measure the camber of head and tail part of strips because many problems are caused by the camber in the hot-rolling process. The hot-rolling process has time constraints. The camber detection algorithm of head and tail parts requires fast and less complex for satisfying time constraints. The proposed algorithm consists of two parts: measurement of the camber in the head and tail part of strips and decision part of the optimal cutting line of hot-rolled strip. First, we obtain the camber value of the strip from the difference between the real center line and the center line of head, tail part. Second, the head and tail part of strips isn't suitable for strips connections. Therefore, the cutting process is needed in the hot-rolling process. The optimal cutting line is determined by the head and tail images obtained from cameras. The algorithm is applied into the vision system with two area cameras, Matrox image processing board and host PC for verification.

• Communications of Mathematical Education
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• v.26 no.1
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• pp.1-13
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• 2012

Ki-Won Chang(1903-1966) is considered as the first mathematician who made a contribution to the study of the history of Korean mathematics. In this paper, we introduce contributions of Ki-Won Chang, his discovery of old Korean literatures on mathematics, and his academic contribution on the history of Korean mathematics. Then we analyze and compare his conclusions on old Korean mathematics with recent works of others. This work shows some interesting discovery.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.4
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• pp.750-756
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• 1997

The purpose of the study was to investigate a transmittance rate of UVB (Ultraviolet B) through summer fabrics and a protection rate of summer fabric from UVB. The subjects were randomly selected 159 fabrics from Korean common summer fabrics. The protection rates of 159 fabrics from UVB were measured by UVB lamp and UVB sensor, and 14 fabrics among these fabrics were selected for an assay of MTT(3-(4, 5-dimethylthiazol-2-yl) -2, 5 -diphenyltetrazolium). The protection rate of fabrics from cell toxicity of UVB was measured by investigating the difference of the amount of cell toxic substance on between fabrics covered with and without HeLa cell The average protection rate of 159 fabrics from UVB was 95.08%. As result findings, three negative correlations were found between: 1) the transmittance rate of UVB and the amount of MTT on fabrics (y=0.0373+0.O0518 x, r=-0.9323, p<0.001); 2) the air permeability of fabrics and the amount of MTT (r: -0.79, p< 0.01); 3) the air permeability of fabrics and the protection rate of fabrics from UVB (r=0.89, p<0.01). However, there was no effect of thickness of fabrics on the protection rate from UVB and the amount of MTT.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.4
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• pp.411-416
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• 2010

Interest in application of ultraviolet light technology for primary disinfection of potable water in drinking water treatment plants has increased significantly in recent years. The efficacy of disinfection processes in water purification systems is governed by several key factors, including reactor hydraulics, disinfectant chemistry, and microbial inactivation kinetics. The objective of this work was to develop a computational fluid dynamics(CFD) model to predict velocity fields, mass transport, chlorine decay, and microbial inactivation in a continuous flow reactor. In this paper, It describe the how to design optimal UV disinfection device for ground water, BWT and rainwater. Spring shape instrument silver coated located in inner side of disinfection chamber. It make lead the active flowing movement target water and maximize disinfection performance. To search the optimal design method, it was performed computer simulation with 3D-CFD discrete ordinates model and manufactured prototype. Using proposed design method, performed simulation and proved satisfied performance.

• PNF and Movement
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• v.12 no.3
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• pp.173-179
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• 2014

Purpose: The purpose of this study is to analyze the effect of arm leg flexion patterns of proprioceptive neuromuscular facilitation on the muscle activation of the contralateral lower extremity. Methods: In this study, Electromyogram MP150(Biopac system, USA) was applied to 20 healthy male subjects. Unilateral arm flexion- abduction- external rotation pattern and Unilateral leg flexion- adduction- external rotation with knee flexion pattern were applied within mid range of the supine position for measurement. The muscle activation of vastus lateralis, biceps femoris, tibialis anterior and gastrocnemius(medialis) muscle of the contralateral lower extremity were compared and analyzed during the applications. Results: The results of this study were summarized as follows: There was a statistically significant difference in the muscle activation of vastus lateralis and biceps femoris between the arm and leg patterns(P<0.05). There was a statistically significant difference in the muscle activation of gastrocnemius and tibialis anterior between the arm and leg patterns(P<0.05). Conclusion: contralateral vastus lateralis, biceps femoris, gastrocnemius and tibialis anterior muscles show the higher muscle activation in the leg pattern than one in the arm pattern.

• PNF and Movement
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• v.12 no.1
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• pp.7-12
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• 2014

Purpose: The purpose of this study is to analyze the effect of the arm extension pattern of proprioceptive exercise program on the muscle activity of the opposite lower extremity. Methods: In this study, electromyogram MP150(Biopac system, USA) was applied to 20 healthy male subjects. Arm extension-adduction-internal rotation pattern was applied within initial, mid and end range in sling position and supine position for measurement. And the effect on the activity of rectus femoris and tibialis anterior muscle of the opposite lower extremity was compared and analyzed. Results: The results of this study were summarized as follows: First, there was a statistically significant difference of the activity of the tibialis anterior muscle within the Initial range in sling position and supine position(P<0.05). Second, there was a statistically significant difference of the activity of the tibialis anterior muscle within the end range in sling position and supine position(P<0.05). Conclusion: Rectus femoris and tibialis anterior muscles shows the higher activity in the supine position than in the sling position. Therefore, the supine position is more appropriate than the sling position to make irradiation on lower extremity muscle with the extension pattern.

• Toxicological Research
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• v.31 no.4
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• pp.363-369
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• 2015

We evaluated the antioxidant activity and anti-wrinkle effects of Aceriphyllum rossii leaf ethanol extract (ARLEE) in vitro using human dermal fibroblasts. The total polyphenol and flavonoid contents of ARLEE were 578.6 and 206.3 mg/g, respectively. At a concentration of $250{\mu}g/mL$, the electron-donating ability of ARLEE was 87.1%. In comparison with the vehicle, ARLEE treatment at $100{\mu}g/mL$ significantly increased type I procollagen synthesis (p < 0.01) by 50.7%. In vitro ARLEE treatment (10 mg/mL) inhibited collagenase and elastase activity by 97.1% and 99.2%, respectively. Compared with the control, ascorbic acid treatment at $100{\mu}g/mL$ significantly decreased matrix metalloproteinase (MMP)-1 protein expression (p < 0.01) by 37.0%. ARLEE treatment at $50{\mu}g/mL$ significantly decreased MMP-1 protein expression (p < 0.01) by 46.1%. Ascorbic acid and ARLEE treatments at $100{\mu}g/mL$ significantly decreased MMP-1 mRNA expression (p < 0.01) by 26.1% and 36.1%, respectively. From these results, we conclude that ARLEE has excellent antioxidant activity and even better anti-wrinkle effects than ascorbic acid in human dermal fibroblasts. These results suggest that ARLEE could be used in functional cosmetics for the prevention or alleviation of skin wrinkles induced by ultraviolet rays.