• 한국해양공학회지
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• 제30권1호
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• pp.18-24
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• 2016

Stabilizer fins are installed on each side of a ship to control its roll motion. The most common stabilizer fin is a rolling control system that uses the lift force on the fin surface. If the angle of attack of a stabilizer fin is zero or the speed is zero, it cannot control the roll motion. The Coanda effect is well known to generate lift force in marine field. The performance of stabilizer fin that applies the Coanda effect has been verified by model tests and numerical simulations. It was found that a stabilizer fin that applied the Coanda effect at Cj = 0.085 and a zero angle of attack exactly coincided with that of the original fin at α = 26°. In addition, the power needed to generate the Coanda effect was not high compared to the motor power of the original stabilizer fin.

• 제어로봇시스템학회논문지
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• 제20권1호
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• pp.12-17
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• 2014

In this paper, we propose a controller capable of reducing the effect of measurement errors under AC and DC noise. Typically, the control system measures data through a sensor. If sensor noise is included in a controller via the feedback channel, the signal is distorted and the entire system cannot work normally. Therefore, some appropriate action to counter the measurement error effect is essential in the controller design. Our controller is equipped with a gain-scaling factor and a compensator to reduce the effect of measurement error in the feedback signal. Also, we use a switching control strategy to enhance the performance of the controller regarding convergence speed. Our proposed controller can therefore effectively reduce the AC and DC noise of the sensor. We analyze the proposed controller by Laplace transform technique and our control method is verified via MATLAB simulation.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1701-1704
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• 2002

In this paper, we investigate the effect of power control step size on the performance of the SIC scheme in DS/CDMA systems. We investigate the average power control iteration and its standard deviation and evaluate the outage performance for several different values of power control step size. Because the SIC scheme requires fine control in the received signal power, the better outage performance is obtained fer the smaller power control step size. However, the smaller power control step size requires larger amount of power control iteration in order to make the power control converge to the steady state. Under the simulated environment, the proper power control step size is about 0.3-0.4dB from both convergence speed of power control algorithm and outage performance points of view.

• 아태비즈니스연구
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• 제14권4호
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• pp.255-273
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• 2023

Purpose - This study examines whether internal control has an effect on stock price informativeness about future earnings. High quality internal control provides continuous assurance for the quality of financial reports, and these future earnings-related information is accurately reflected in the current stock price. Design/methodology/approach - This study collected 12,862 data from 2006 to 2021 in China to make an empirical analysis using the future earnings response coefficient (FERC) and the multiple regression analysis were hired in order to analyze the data. Findings - We find that internal control strengthens the association between current returns and future earnings, indicating that more information about future earnings is reflected in current stock prices. This positive effect exists in both the main board market and the growth enterprise market of China's stock market, especially in the main board market after the implementation of the internal control policy. In addition, we find that the positive effect is weaker for firms that report internal control deficiencies or receives non unqualified internal control audit opinions. The results using earnings persistence yield similar findings, further supporting the results based on the FERC model. Research Implications or Originality - Our tests provide strong evidence that the quality of internal control affects FERC in China stock market.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.580-583
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• 2003

The general time optimal control law provides the optimal solution for a minimum time control problem. But in most real systems with disturbances and model uncertainties, the time optimal control law leads to chattering effect. This chattering effect can cause the system to be unstable. Therefore, we propose a robust optimal control algorithm for the nonlinear second order systems with model uncertainty. The proposed algorithm is combined with bang-bang control and sliding mode control. Thus the proposed algorithm has two state space regions to implement to control algorithm. In each region, the appropriate linear or nonlinear feedback control law is used satisfying the dynamic system equations. Simulation results show the superiority of the proposed controller in comparison with pure time optimal control(bang-bang control).

• 한국생활과학회지
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• 제23권6호
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• pp.1141-1154
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• 2014

The purpose of this study examined the moderating effect of maternal emotion-related socialization behaviors on the relations between preschooler's effortful control and prosocial behavior. In this study, subjects were 153 preschoolers and their mothers. The major results were as follows; there was a moderating effect of maternal emotion-related socialization behaviors on the relationship between preschooler's effortful control and prosocial behavior. Specifically, maternal negative emotion expression and response to the preschooler's positive emotion moderated the effect preschooler's effortful control on prosocial behavior. In conclusion, the impact of effortful control on preschooler's prosocial behavior were significant. Also, maternal emotion-related socialization behaviors(i.e., negative emotion expression and response to the child's positive emotion) affected on preschooler's prosocial behavior. The findings of the study will contribute to help maternal emotional interaction with their preschool aged children.

• 한국조명전기설비학회지:조명전기설비
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• 제9권6호
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• pp.78-82
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• 1995

It is needed to robust control for D.C. servo motor according to industrial automation. However, when a motor has an effect of disturbance and variable load, it is very difficult to guarantee the robustness of the system. as a compensation way of solving this problem, in this paper, a expert supervisory control method for motor control system is presented. Expert supervisory controller is designed by error and error change, and nth control input is decided by the addition of (n-1)th control input and inference amount of increase or decrease. Control input of expert supervisory control is transmitted to input, and the disturbance effect decrease remarkable by control input. The robustness of D.C. servo motor using expert supervisory control is demonstrated by the computer simulation.

• 동력기계공학회지
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• 제10권1호
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• pp.90-95
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• 2006

Pneumatic control systems have been mainly used as a high speed operating system. Therefore, state change of air in a control volume was assumed to be adiabatic change and, pneumatic control systems have been analyzed by using this assumption. Especially, when absolute value of pressure change in the control volume is small, there is a tendency to neglect effect of temperature change on pneumatic control system because temperature change owing to pressure change is small. In this study, an effect of temperature change of air on the decompression control process was analyzed by considering change of mass flow rate, and heat transfer characteristics between air in the chamber and the chamber wall. As a result, this study could confirm that a slight temperature change of the air in the pneumatic pressure control system can influence on the dynamic characteristics of pressure response, and pressure control performance.

• 대한한방부인과학회지
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• 제21권1호
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• pp.55-82
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• 2008

Purpose: In this study, we evaluated anti-inflammatory activity and anti-thrombosis effect of Manbunbang(MBB) prescribed to chronic PID patients. Methods: We studied inhibitory effect of platelet aggregation, suppression effect of GPIIb/IIIa activity and inhibitory effect of $TXB_2$ and $PGE_2$ biosynthesis which were caused by ADP, epinephrine, collagen and arachidonic acid in vitro. And suppression of pulmonary embolism, changes of related factors in dextran coagulation condition model and anti-oxidative effect of oxidative damage were studied in vivo. Results: MBB extract showed LD50 of $200\;{\mu}g/ml$ or higher in mouse lung fibroblast cells, and significantly decreased the GPT and GPT level in dextran coagulation condition model compared to the control. MBB extract showed dose-dependent inhibition effect on platelet coagulation induced by ADP, epinephrine, collagen, arachidonic acid. MBB extract showed dose-dependent inhibition effect on GPIIb/IIIa activities compared to the control. MBB extract significantly suppressed TXB2 and PGE2 biosynthesis compared to the control. MBB extract suppressed pulmonary embolism triggered by collagen and epinephrine by 37.5% compared to the control. MBB extract significantly suppressed the decrease of speed of bloodstream caused by blood coagulation in dextran coagulation condition model compared to the control. Concluson : The results strongly suggest the anti-inflammatory activity of Manbunbang through anti-thrombus. Various applications using Manbunbang on inflammatory diseases are anticipated. Anti-oxidative efficacy comparison data between the Manbunbang prescription and the drug compositions may be used as important clinical information, and further investigation of anti-oxidative activities of Chrysanthemum indicum and Rhemaniae Radix should be followed.

• 동의신경정신과학회지
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• 제15권1호
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• pp.101-119
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• 2004

Ginseng Radix Alba and Cyperi Rhizoma were investigated for their anti-depressant effects. For this purpose, forced-swimming test, tail suspension test, hot plate test, reserpine-induced hypothermia, aggressive behavior test were performed. In addition, the brain content of 5-hydroxyindoleacetic acid(a metabolite of serotonin), the monoamine oxidase activity, anticonvulsant effect, sleep enhancement effect were determined. The results are as follows: In the forced swimming test, Ginseng Radix diminished the duration of immobility by 45.5% compared to the control group, while Cyperi Rhizoma showed weaker effect (12.4% reduction) at 2g/kg. In the tail suspension test, the effect of Ginseng Radix(43.7% reduction) are also better than that of Cyperi Rhizoma(15.6% reduction) at 2g/kg. In the hot plate test, Ginseng Radix showed no difference as compared to control, while Cyperi Rhizoma increased the jump latency time by about 25% after administration for 10 days. In the reserpine-induced hypothermia test, both drugs slowly dropped the body temperature compared to the control group, especially the rate of hypothermia of Ginseng Radix was 24.0% at 1g/kg. In the aggressive behavior test, both drugs delayed the onset time, decreased the duration and frequency, of which effects were better in Cyperi Rhizoma. The content of 5-hydroxyindoleacetic acid in mice brain was slightly increased in Ginseng Radix, while Cyperi Rhizoma increased its level almost to the control group. Both drugs inhibited the monoamine oxidase activity in a dose-dependent manner, but the effect(51.2%) of Cyperi Rhizoma was more potent than the effect(11.8%) of Ginseng Radix. In the pentobarbital-induced sleep test, Cyperi Rhizoma exhibited no significant difference against the control group, while Ginseng Radix showed about two-fold enhancement at 2g/kg. The anticonvulsant effect of both drugs delayed the onset time, shortened the duration of convulsion and diminished the lethality, but Ginseng Radix were better than Cyperi Rhizoma.