• 한국초전도ㆍ저온공학회논문지
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• 제24권1호
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• pp.13-17
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• 2022

The mechanical properties of REBCO coated conductor (CC) tapes under uniaxial tension are mainly determined by the thick layer Components like the substrate and the stabilizer. Depending on the applications of the CC tapes, it is also needed to externally reinforce thin metallic foils to one side or both sides of the CC tapes. This study investigated the effect of additional stabilizer layers or lamination on the electrical resistivity and electromechanical properties in RCE-DR processed GdBCO CC tapes with different structures. The strain/stress tolerance of I_c in differently processed 12 mm-wide REBCO CC tapes under uniaxial tension at 77 K and self-field could be determined by the loading-unloading scheme. As a result, Sn-Cu stabilized CC tape showed a significant decrease in mechanical properties due to its soft but thick stabilizing layer. However, similar electromechanical properties have been observed on both Sn-Cu and Sn-stabilized CC tapes, the I_c degradation behavior was independent of whether the CC tape has an external reinforcement or different stabilizing layers.

• 한국지능시스템학회논문지
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• 제8권2호
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• pp.50-59
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• 1998

This paper presents stabilization and adaptive control of flexible single link robot manipulator system by self-recurrent neural networks that is one of the neural networks and is effective in nonlinear control. The architecture of neural networks is a modified model of self-recurrent structure which has a hidden layer. The self-recurrent neural networks can be used to approximate any continuous function to any desired degree of accuracy and the weights are updated by feedback-error learning algorithm. When a flexible manipulator is rotated by a motor through the fixed end, transverse vibration may occur. The motor toroque should be controlled in such a way that the motor rotates by a specified angle, while simultaneously stabilizing vibration of the flexible manipuators so that it is arresed as soon as possible at the end of rotation. Accurate vibration control of lightweight manipulator during the large changes in configuration common to robotic tasks requires dynamic models that describe both the rigid body motions, as well as the flexural vibrations. Therefore, a dynamic models for a flexible single link robot manipulator is derived, and then a comparative analysis was made with linear controller through an simulation and experiment. The results are proesented to illustrate thd advantages and imporved performance of the proposed adaptive control ove the conventional linear controller.

• 전자공학회논문지B
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• 제29B권8호
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• pp.1-6
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• 1992

This paper proposed a neural computer architecture for the learning of script character pattern recognition categories. Oriented filter with complex cells preprocess about the input script character, abstracts contour from the character. This contour normalized and inputed to the ART. Top-down attentional and matching mechanisms are critical in self-stabilizing of the code learning process. The architecture embodies a parallel search scheme that updates itself adaptively as the learning process unfolds. After learning ART self-stabilizes, recognition time does not grow as a function of code complexity. Vigilance level shows the similarity between learned patterns and new input patterns. This character recognition system is designed to adaptable. The simulation of this system showed satisfied result in the recognition of the hand written characters.

• 천문학회지
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• 제37권4호
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• pp.243-248
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• 2004

Disk galaxies abound with intermediate-scale structures such as OB star complexes, giant clouds, and dust spurs in a close geometrical association with spiral arms. Various mechanisms have been proposed as candidates for their origin, but a comprehensive theory should encompass fundamental physical agents such as self-gravity, magnetic fields, galactic differential rotation, and spiral arms, all of which are known to exist in disk galaxies. Recent numerical simulations incorporating all these physical processes show that magneto-Jeans instability (MJI), in which magnetic tension resists the stabilizing Coriolis force of galaxy rotation, is much more powerful than swing-amplification or the Parker instability in forming self-gravitating intermediate-scale structures. The MJI occurring in shearing and expanding flows off spiral arms rapidly forms structures elongated along the direction perpendicular to the arms, remarkably similar to dust spurs seen in HST images of spiral galaxies. In highly nonlinear stages, these spurs fragment to form bound clumps, possibly evolving into bright arm and interarm H II regions, suggesting that all these intermediate-scale structures in spiral galaxies probably share a common dynamical origin.

• 미생물학회지
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• 제35권4호
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• pp.253-257
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• 1999

Cadaverine, putrescine, spermidine과 spermine이 spectinomycin에 의한 T4 파지 thymidylate synthase 유전자(td) intron의 splicing 억제에 미치는 영향을 조사하였다. Polyamine이 존재하지 않는 상태에서 7mM spectinomycin은 splicing rate를 약 40% 감소시켰다. 사용한 농도 범위(0.1~5mM)에서 cadaverine은 splicing rate를 감소시켰으나, putrescine은 0.5mM 농도에서 약 13% 정도의 splicing rate를 증가시켰다. Spermidine은 0.5mM 농도에서 약 11% 정도의 splicing rate를 증가시켰으며, sperimine은 0.01mM 농도에서 약 16% 정도의 splicing rate을 증가시켰다. 시험한 polyamine 중에서 특히 sperimine은 가장 낮은 농도에서 spectinomycin에 의한 억제반응을 극복하는 최고의 활성효과를 나타냈다. 이와 같은 억제 회복 효과는 polyamine에 의한 td intron 리보자임의 구조적 안정성에 기인하는 것으로 추정된다.

• Child Health Nursing Research
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• 제7권3호
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• pp.383-396
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• 2001

This study was designed to investigate the effects of the progressive muscle relaxation on behavioral states and emotional reactions of adolescent athletes. The participants were 167 adolescent male soccer players aged between 12 and 18 who were junior or high school students in Seoul. Ninety-three of them were assigned to the experimental group, while seventy-four to the control group. The experimental group was treated by 10 sessions (20 min./session) of Jacobson's progressive muscle relaxation for two weeks, while the control group was not treated. The self and observer reported behavioral states, general stress by visual analogue scale, physical symptoms of stress, athletic stress, state anxiety, depression, self-esteem were measured before and after two weeks of the progressive muscle relaxation. The results were as follows ; 1. The self and observer reported behavioral states were significantly decreased in the experimental group compared with the control group. 2. The general stress and the gastrointestinal symptoms of stress were significantly decreased in the experimental group compared with the control group. No significant difference on athletic stress was found between the two groups. The depression and the state anxiety were significantly decreased in the experimental group compared with the control group. The self-esteem was significantly increased in the experimental group compared with the control group. 3. The influential factors on behavioral state of adolescent male athlete were depression and state anxiety. The accelerating factor on behavioral state change after the progressive muscle relaxation was state anxiety. These results are suggested that the progressive muscle relaxation could be effective in stabilizing behavioral state, decreasing general stress, gastrointestinal symptoms of stress, depression, state anxiety, in increasing self-esteem of adolescent male athletes. And the behavioral state change after the progressive muscle relaxation was influenced by state anxiety.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제2권8호
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• pp.507-516
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• 2013

모바일 디바이스는 크기가 작기 때문에 PC에 비해 컴퓨팅 자원이 부족하여, 높은 복잡도를 가진 애플리케이션을 설치 및 운영하기 어렵다. 그러나, 모바일 디바이스는 풍부한 네트워크 연결 능력이 있어 외부 자원을 사용하기가 용이하므로, 모바일 클라우드 컴퓨팅 (Mobile Cloud Computing, MCC) 연구가 활발히 진행되고 있다. MCC에서는 주로 기능 컴포넌트를 다른 노드로 오프로딩 (Offloading) 시킴으로써, 모바일 노드의 자원 문제를 해결하는 접근법을 적용한다. 그러나, 현재 진행되고 있는 MCC에 대한 연구는 사전에 결정된 노드로 오프로딩하는 연구만 위주로 진행되고 있으며, 모바일 디바이스가 구독하는 서비스 문제를 해결할 수 없는 한계점이 있다. 본 논문에서는 자율 안정화할 수 있는 MCC를 구현하기 위한 실용적인 프로세스와 품질 안정화 기법을 제안한다. 먼저, 효과적으로 품질을 관리하기 위한 MCC 메타모델을 제시하고, 이를 기반으로 8개의 활동으로 구성된 품질 관리 프로세스를 제안하며, 핵심 활동에 대한 상세 기법을 정의한다. 그리고, 실용적 수준으로 연구가 많이 진행되지 않은 오프로딩 기법을 MCC 메타모델에 제시된 여러 요소들과 상호작용하여 QoS 문제를 효과적으로 해결할 수 있도록 설계한다. 마지막으로 실험을 통해 품질 자율 관리 프로세스의 적절성을 증명한다. MCC의 품질 자율 안정 관리 프로세스와 품질 향상 기법들을 채택함으로써, 클라우드 서비스를 구독하는 모바일 애플리케이션의 품질을 관리하는데 여러 기술적 이슈를 효과적으로 해결할 수 있다. 그리고, MCC에 속한 여러 애플리케이션과 서비스들은 관리자의 개입없이 자율적으로 일정 수준의 품질을 유지할 수 있게 된다.

• 전자공학회논문지B
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• 제33B권2호
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• pp.168-177
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• 1996

In this paper, we propose an on-line recognition system of chinese characters using an adaptive resonance theory-1(ART-1) neural network. Strokes, primitive components of chinese characters are usually warped into a cursive form and classifying them is very difficult. To deal with such cursive strokes, we use an ART-1 neural network that has the following advantages: (1) it automatically assembles similar patterns together to form classes in a self-organized manner: (2) it directly accesses the recognition codes corresponding to binary input patterns after self-stabilizing; (3) it doesn't tends to get trapped in local minima, or globally incorrect solutions. A database for character recognition also dynamically constructed with generalized character lists, and a new character can be included simply by adding a new sequence to the list. Character recognition is achieved by traversing the chinese datbase with a sequence of recognized strokes and positional relations between the strokes. To verify the performance of the system. We tested it for 1800 daily-used basic chinese second per character. This results suggest that the proposed system is pertinent to be put into practical use.

• The Journal of Asian Finance, Economics and Business
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• 제7권9호
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• pp.329-340
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• 2020

This study investigates the effect of capital structure on the financial performance of pharmaceutical enterprises which are listing on Vietnam's stock market. The study builds the regression using ROE as dependent variable and four independent variables, including self-financing, financial leverage, long-term asset and debt to assets ratios. In addition, we use other variables as controlling ones, such as firm size, fixed asset rate and growth. We collect data for the period from 2015 to 2019 of all 30 pharmaceutical enterprises which are currently listing on Vietnam's stock market. The least square regression (OLS) is used to test the effect of capital structure to the firms' financial performance. The analysis results show that the financial leverage ratio (LR), long-term asset ratio (LAR) and debt-to-assets ratio (DR) have positive relationship with firm performance, meanwhile the self-financing (E/C) affects negatively to the return on equity (ROE). Upon the findings we suggest that the Vietnamese government should focus on stabilizing macro environment to create favorable environment for enterprises. And the pharmaceutical enterprises should build more reasonable capital structure with higher debt proportion than equity, diversifying loan mobilization channels such as issuing long-term bonds. Additionally, the firms should expand the scale appropriately to maintain development and ability to pay debts.

• 한국재료학회지
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• 제31권1호
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• pp.8-15
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• 2021

Transparent, photocatalytic, and self-cleaning TiO2 thin film is developed by TiO2 sol-gel coating on glass and polycarbonate (PC) substrates. Acetyl acetone (AcAc) suppresses the precipitation of TiO2 by forming a yellowish (complex) transparent sol-gel. XPS analysis confirms the presence of Ti2p and O1s in the thin films on glass and PC substrates. The TiO2-sol is prepared by stabilizing titanium (IV) isopropoxide (TTIP) with diethylamine and methyl alcohol. The addition of AcAcsilane coupling solution to the TiO2-sol instantaneously turns to yellowish color owing to the complexing of titanium with AcAc. The AcAc solution substantially improves the photocatalytic property of the TiO2 coating layer in MB solutions. The coated TiO2 film exhibits super hydrophilicity without and with light irradiation. The TiO2 thin film stabilized by adding 8.7 wt% AcAc shows the highest photo-degradation for methylene blue (MB) solution under UV light irradiation. Also, the optimum photocatalytic activity is obtained for the 8.7 wt% AcAc-stabilized TiO2 coating layer calcined at 450 ℃. The thin-films on glass exhibit fast self-cleaning from oleic acid contamination within 45 min of UV-light irradiation. The appropriate curing time at 140 ℃ improves the anti-fogging and thermal stability of the TiO2 film coated on PC substrate. The watermark-free PC substrate is particularly beneficial to combat fogging problems of transparent substrates.