• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.8
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• pp.1449-1455
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• 2010

The excitation control system of an emergency diesel generator is classified as a kind of safety-related system. Compared with other control systems in a power plant, this system is required to be more reliable and have better performance. In this paper, the digital multi-redundant excitation system for a diesel generator was proposed. The signal processing system of the proposed system makes high speed signal processing and arithmetic in excitation control possible. The improved soft start algorithm and multiple PI parameters adaptation considering the diesel generator characteristics were implemented in the proposed system. The developed system was applied to a nuclear power plant successfully.

• International Journal of Control, Automation, and Systems
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• v.3 no.spc2
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• pp.288-295
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• 2005

In this paper a new adaptive, decentralized excitation control scheme proposed to enhance the transient stability of multimachine power systems is extensively analyzed with respect to its robustness and disturbance attenuation. As shown in the paper, both robustness and disturbance attenuation can be effectively improved by suitably selecting the design parameters of the proposed controller. Particularly, some simple rules for the selection of the control gains and the adaptation parameters are extracted which, as it is proven, may be essential for the system performance. Simulation tests on a two generator infinite bus power system absolutely confirm the theoretical results.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.10
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• pp.13-21
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• 1998

In this paper, we analyze the main-carrier cancellation characteristics of the nulling loop control circuit which is used for the main-carrier cancellation circuit of the feedforward linear power amplifier. A new nulling loop error control method is proposed to improve the linear power amplifier characteristics. With this analysis, the main carrier cancellation ratio can be estimated and the required specifications of the main and auxiliary amplifiers can be optimized for the economic and power efficiency.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.3
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• pp.326-333
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• 2015

This paper reports an adaptive positive feedback bias control technique for operational transconductance amplifiers to adjust the bias current based on the output current monitored by a current replica circuit. This technique enables operational transconductance amplifiers to quickly adapt their power consumption to various analog workloads when they are configured with negative feedback. To prove the concept, a test voltage follower is fabricated in $0.5-{\mu}m$ CMOS technology. Measurement result shows that the power consumption of the test voltage follower is approximately linearly proportional to the load capacitance, the signal frequency, and the signal amplitude for sinusoidal inputs as well as square pulses.

• Journal of Industrial Convergence
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• v.21 no.11
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• pp.117-124
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• 2023

This study is a descriptive research study to determine the relationship between nursing students' emotional intelligence, communication competence, interpersonal competence, and adaptation to college life, and to identify factors that adaptation to college life. The subjects of the study were 173 nursing students attending a university in G City, and data collection was conducted from September 10 to October 10, 2022 Descriptive statistics, t-test, ANOVA, Pearson correlation coefficient, and multiple regression analysis were performed on the collected data using SPSS 25.0 program. The results showed a significant positive correlation between emotional intelligence(r=.760, p<.001), communication competence(r=.600, p<.001), and interpersonal competence(r=.451, p<.001). Factors that have a significant impact on adaptation to college life include emotional intelligence(𝛽=.543, p<.001), communication competence(𝛽=.433, p=.001), and interpersonal competence(𝛽=.283, p<.031). The total explanatory power of these variables on adaptation to college life was 59.9%, and emotional intelligence was confirmed to be the main influencing factor.

• The Journal of the Convergence on Culture Technology
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• v.10 no.5
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• pp.557-567
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• 2024

This study was a descriptived research study to determine the impact of empathy, communication competence, and personality on college adaptation among nursing students attending a university in City Y. The research method was a self-administered survey targeting 200 nursing students at a university in Y City, and data were collected from April 29, 2024 to May 27, 2024. The research statistical method used was the SPSS/WIN 25.0 statistical program, and was analyzed using t-test, one-way analysis of variance, Pearson correlation, and multiple regression analysis. In the correlation between each variable, college adaptation is related to empathy(r=.522, p<.001), communication competence(r=.557, p<.001), and personality(r=.561, p<.001). And as a result of regression analysis, as a factor affecting the subjects' college adaptation, second-year students(β=-.148, p=.013) had a higher level of college adaptation than first-year students(β=-.297, p<.001). Additionally, the level of college adaptation was high in the order of empathy(β=.295, p<.001), personality(β=.230, p<.001), and communication competence(β=.157, p=.050), and the explanatory power was 47.6%(Adj R2=.476, p<.001). Therefore, in order for nursing students to adapt to college, various psychological and emotional supports must be provided at the school and department level, and various customized programs that can improve empathy, communication competence, and personality should be developed and applied by considering the characteristics of nursing students by grade.

• Journal of Platform Technology
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• v.6 no.3
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• pp.38-46
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• 2018

Smart Grid is an intelligent power grid for efficiently producing and consuming electricity through bi-directional communication between power producers and consumers. As renewable energy develops, the share of renewable energy in the smart grid is increasing. Renewable energy has a problem that it differs from existing power generation methods that can predict and control power generation because the power generation changes in real time. Applying a self-adaptative framework to the Smart Grid will enable efficient operation of the Smart Grid by adapting to the amount of renewable energy power generated in real time. In this paper, we assume that smart villages equipped with photovoltaic power generation facilities are installed, and apply the self-adaptative framework, AiTES, to show that smart grid can be efficiently operated through self adaptation framework.

• Journal of Communications and Networks
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• v.15 no.5
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• pp.476-485
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• 2013

In this paper, the effective capacity of a multiple-input multiple-output (MIMO) system in two different cases with receive antenna selection (RAS) and transmit antenna selection (TAS) schemes is investigated. A closed-form solution for the maximum constant arrival rate of this network with statistical delay quality of service (QoS) constraint is extracted in the quasi-static fading channel. This study is conducted in two different cases.When channel state information (CSI) is not available at the MIMO transmitter, implementation of TAS is difficult. Therefore, RAS scheme is employed and one antenna with the maximum instantaneous signal to noise ratio is chosen at the receiver. On the other hand, when CSI is available at the transmitter, TAS scheme is executed. In this case, one antenna is selected at the transmitter. Moreover, an optimal power-control policy is applied to the selected antenna and the effective capacity of the MIMO system is derived. Finally, this optimal power adaptation and the effective capacity are investigated in two asymptotic cases with the loose and strict QoS requirements. In particular, we show that in the TAS scheme with the loose QoS restriction, the effective capacity converges to the ergodic capacity. Then, an exact closed-form solution is obtained for the ergodic capacity of the channel here.

• Journal of Power Electronics
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• v.14 no.1
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• pp.125-134
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• 2014

This paper presents a robust and speed-sensorless stator flux estimation for induction motor direct torque control. The proposed observer is based on sliding mode approach. Stator electrical equations are used in the rotor orientation reference frame to eliminate the observer dependence on rotor speed. Lyapunov's concept for systems stability is adopted to confine the observer gain. Furthermore, the sensitivity of the observer to parameter mismatch is recovered with an adaptation technique. The nonlinearities of the pulse width modulation voltage source inverter are estimated and compensated to enhance stability at low speeds. Therefore, a new method based on the model reference adaptive system is proposed. Simulation and experimental results are shown to verify the feasibility and effectiveness of the proposed algorithms.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.179.1-179.1
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• 2010

This paper has represented about the wind power industry of the west-south seashore with leading industry development for Honam Economic Region. These projects have composed of wind power industry of the west-south seashore, offshore wind turbine(2MW, 3MW) and onshore wind turbine(3kW, 5kW, 10kW), 11 projects, during 3 years- with honam leading industry development for economic region. The contents of these project are 3 favorable products and 3 business support projects. The favorable products are the MW offshore wind system with Outer-rotor type PMSG, the 3MWoffshore wind system with adaptation type of west-south sea, the hybrid generator system with wind turbine technology basis.