• 대한조선학회논문집
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• 제48권2호
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• pp.113-120
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• 2011

Fins are widely used for roll stabilization of passenger ferries and high performance naval ships, among others. The Coanda effect is noticeable when a jet stream is applied tangentially to a curved wing surface since the jet can augment the lift by increasing the circulation. The Coanda effect has been found useful in various fields of aerodynamics and speculated to have practical applicability in marine hydrodynamics where various control surfaces are used to control motions of ships and the other offshore structures. In the present study, numerical computations have been performed to find proper jet momentum coefficients $C_j$ and trailing edge shapes suitable for the application of the Coanda effect to a stabilizer fin. The results show that the lift coefficient of the modified Coanda fin at the zero angle of attack ${\alpha}$ identically coincides with that of the original fin at ${\alpha}\;=\;25^{\circ}$ when Coanda jet is supplied at the rate of $C_j$ = 0.1. It is also shown that a fixed type fin stabilizer utilizing the Coanda effect can be implemented without changing the fin angle to actively control the motions of ships and the other offshore structures.

• Smart Structures and Systems
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• 제24권1호
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• pp.1-14
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• 2019

Transmission tower-line system is one of most critical lifeline systems to cities. However, it is found that the transmission tower-line system is prone to be damaged by earthquakes in past decades. To mitigate seismic demands, this study introduces a tuned-mass damper (TMD) using superelastic shape memory alloy (SMA) spring for the system. In addition, considering the dynamic characteristics of both tower-line system and SMA are affected by temperature change. Particular attention is paid on the effect of temperature variation on seismic behavior. In doing so, the SMA-TMD is installed into the system, and its properties are optimized through parametric analyses. The considered temperature range is from -40 to $40^{\circ}C$. The seismic control effect of using SMA-TMD is investigated under the considered temperatures. Interested seismic performance indices include peak displacement and peak acceleration at the tower top and the height-wise deformation. Parametric analyses on seismic intensity and frequency ratio were carried out as well. This study indicates that the nonlinear behavior of SMA-TMD is critical to the control effect, and proper tuning before application is advisable. Seismic demand mitigation is always achieved in this wide temperature range, and the control effect is increased at high temperatures.

• 한국치위생학회지
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• 제1권1호
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• pp.133-142
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• 2001

The authors have studied the 8 weeks clinical examination On 32 patients of age 20s for experimental group and 34 patients of the same ages for control group, in order to find out the effect of plaque removal effect and gingival effect by use of the dentifrice contained with the Artemisiae Capillaris extract(dimethylesculetin) and NaCl. The obtained results are as followings: 1. Plaque removal effect is better at the experimental group than at the control group on 2 and 8 weeks(p<0.05). 2. There are not significantly differences on the calculus index and stain index between the experimental group and control group, during the 8 weeks experiment(p>0.05). 3. At the 8 weeks experiment, it revealed the less average scores on the PMA index for experimental group, than that of the control group(p<0.05).

• 치위생과학회지
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• 제12권2호
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• pp.181-188
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• 2012

치위생과 학생의 통제소재와 자기효능감이 스트레스에 미치는 영향을 규명하여 학생들의 학교생활지고와 학습지도에 필요한 기초자료를 제공하고자 2011년 3월 10일부터 3월 20일까지 경기도에 소재한 A여대의 치위생과 학생들을 대상으로 연구를 시행하여 다음과 같은 결론을 얻었다. 1. 통제소재는 평균 8.77로 학생들이 사용하는 통제소재는 내적통제에 가깝다고 할 수 있다. 또한 전체 자기효능감의 평균은 3.23, 일반적 자기효능감은 3.23, 사회적 자기효능감은 3.20으로 평균이상의 자기효능감을 가지고 있었다. 스트레스에서는 전체스트레스평균은 2.32, 교우문제스트레스는 2.05, 경제문제스트레스는 2.33, 진로문제스트레스는 2.29, 부모가족문제스트레스는 2.24, 학업문제스트레스는 2.95로 나타났다. 2. 스트레스는 통제소재와 전체 자기효능감과 부적상관을 보이는 것으로 나타났고 통제소재와 전체 자기효능감은 정적 상관이 있는 것으로 나타났다 (p<.001). 3. 통제소재와 자기효능감이 스트레스에 미치는 영향을 확인한 결과 자기효능감은 전반적인 스트레스에 부적으로 유의한 영향을 끼쳤지만(p<.001) 통제소재는 통계적으로 유의한 결과를 끼치지 않았다. 하위요인에서 자기효능감은 교우문제, 경제문제, 진로문제, 부모가족문제 스트레스에 부적으로 유의한 영향을 미쳤으나(p<.05, p<.001) 통제소재는 통계적으로 유의한 결과를 끼치지 않았으며 학업문제스트레스에는 자기효능감, 통제소재 모두 유의한 영향이 없었다. 4. 통제소재와 스트레스에서 자기효능감의 매개효과를 살펴보면 통제소재가 전체 자기효능감을 거쳐 스트레스로 가는 간접효과가 통계적으로 유의한 것으로 나타났다(p<.001). 결론적으로 자기효능감을 비롯한 치위생과 학생들의 스트레스를 완화시키는 요인들에 관한 관심과 방법의 모색이 필요하다.

• Human Ecology Research
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• 제58권3호
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• pp.299-313
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• 2020

This study investigated the relationship among fathers' parenting involvement, mothers' parenting competence, and young children's self-control. Participants consisted of 325 mothers and young children (169 boys and 153 girls) from the Seoul area who completed questionnaires on fathers' parenting involvement, mothers' parenting competence, and young children's self-control. Data were statistically analyzed using basic descriptive statistics, Pearson's correlation, and multiple regression analysis. Baron and Kenny's method was examined. Subsequently, the Sobel test was performed to check the mediating model's significance and was adapted to SPSS version 21.0 for Windows. The major findings were as follows. First, fathers' parenting involvement was positively correlated with young children's self-control and mothers' parenting competence. Second, mothers' parenting competence was positively correlated with young children's self-control. The mothers' parenting competence indicated a tendency to play a perfectly/partially play a mediating role between fathers' parenting involvement and young children's self-control; consequently, a fathers' parenting involvement had a direct effect as well as an indirect effect through the mothers' parenting competence on young children's self-control. The results indicated that a mothers' parenting competence plays a crucial role in the relationship between a fathers' parenting involvement and the young children's self-control.

• 로봇학회논문지
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• 제15권1호
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• pp.77-89
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• 2020

This paper proposes a simple and intuitive model-free torque-tracking control for rotary electro-hydraulic actuators. The undesirable natural-velocity-feedback effect is discussed by introducing mechanical impedance into the electro-hydraulic actuation system. The proposed model-free torque control comprises inner- and outer-loop control to achieve two control objectives. Inner-loop control reduces the mechanical impedance passively and optimally. To improve the tracking accuracy, a certain form of proportional-integral-derivative control is applied to the outer loop. The robustness of the proposed closed-loop system against external disturbances is demonstrated by transforming the two-loop control structure into a disturbance observer form. The proposed method is validated on a single joint electro-hydraulic actuator.

• 한국멀티미디어학회논문지
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• 제25권8호
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• pp.1097-1108
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• 2022

This paper aimed to design and implement an EMS for real-time power generation control based on wake effect optimization of wind farm, and then to test it in commercial operating wind farm. For real-time control, we proposed the wake band-based optimization and setting the wake effect distance limit, and when the wake effect distance limit was set to 7D in the actual wind farm layout, the calculation time was improved by about 93.94%. In addition, we designed and implemented the script-based EMS for flexible operation logic management in preparation for unexpected issues during testing, and it was installed and tested on a wind farm in commercial operation. However, three issues arose during the testing process. These are the communication interface problem of meteorological tower, the problem of an abnormal wake effect, and the problem of wind turbine yaw control. These issues were solved by modifying the operation logic using EMS's script editor, and the test was successfully completed in the wind farm in commercial operation.

• 한국콘텐츠학회논문지
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• 제16권7호
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• pp.100-111
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• 2016

본 연구는 노인의 스트레스와 성공적 노화에 있어 낙관성과 가족지지의 매개된 조절효과 검증을 위해 경남지역에 거주하는 65세 이상의 일반노인 584명을 대상을 분석하였다. 분석은 Preacher와 Hayes가 제안한 SPSS Macro방법을 사용하여 경로모형을 통해 연구모형을 검증하였다. 연구모형 검증은 3단계로 실시하였으며, 1단계는 예측변수와 준거변수 관계에서 조절변수가 조절효과를 가지는가를 분석하였고, 2단계는 예측변수와 매개변수의 관계를 확인 후, 3단계에서는 매개된 조절효과를 확인하였다. 분석한 결과를 요약하면 다음과 같다. 첫째, 스트레스와 성공적 노화, 낙관성의 매개효과를 검증한 결과 부분매개모형을 지지하는 것으로 확인되었다. 둘째, 스트레스, 낙관성과 성공적 노화의 가족지지 조절효과를 검증한 결과 조절효과가 모두 있는 것으로 확인되었다. 셋째, 스트레스, 낙관성과 성공적 노화, 가족지지의 매개된 조절효과를 검증한 결과 매개된 조절효과가 있는 것으로 나타났다. 이러한 연구결과를 바탕으로 실천적 함의와 향후 과제를 제시하고, 노년기 성공적 노화를 위한 가족지지 향상방안을 제시하였다.

• Journal of Information Processing Systems
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• 제18권4호
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• pp.510-523
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• 2022

Considering the problems of poor control effect, weak disturbance rejection ability and adaptive ability of two-wheeled self-balanced robot (TWSBR) systems on undulating roads, this paper proposes a fuzzy neural network active disturbance rejection controller (FNNADRC), that is based on fuzzy neural network (FNN) for online correction of active disturbance rejection controller (ADRC)'s nonlinear control rate. Firstly, the dynamic model of the TWSBR is established and decoupled, the extended state observer (ESO) is used to compensate dynamically and linearize the upright and displacement subsystems. Then, the nonlinear PD control rate and FNN are designed, and the FNN is used to modify the control parameters of the nonlinear PD control rate in real time. Finally, the proposed control strategy is simulated and compared with the traditional ADRC and fuzzy active disturbance rejection controller (FADRC). The simulation results show that the control effect of the proposed control strategy is slightly better than ADRC and FADRC.

• 아시안잔디학회지
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• 제13권3호
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• pp.131-138
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• 1999

A synergistic effect of biocontrol agent and chemicals on control of the large patch on turfgrass caused by Rhizoctonia solani AG2-2 was evaluated. Chemicals; mepronil, toclofos-methyl and iprodione inhibited 90∼100% mycelial growth of R. solani AG1 and AG2-2 in vitro. While on the other, the chemicals inhibited only 0∼5%, 18∼46% and 30∼67% of mycelial growth of the antagonists, respectively. In field application, toclofos-methyl was the best to suppress the disease in single application, however, the combination of mepronil and T. viride 41D showed highest disease control effect among combinations of antagonists and chemicals. Effect of the combination of mepronil and T. viride 41D was similar to that of toclofos-methyl and T. viride 41D stage of disease development, but became higher in six week late. Results indicated that the combined application of selected antagonistic agent and chemical increased control efficasy of turgrass large patch.