• Journal of Korean Academy of Nursing
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• v.45 no.2
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• pp.251-261
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• 2015

Purpose: The purpose of this study was to develop an integrated internet addiction prevention program and test its effects on the self-regulation and internet addiction of elementary students who are at risk for internet addiction. Methods: A quasi-experimental study with a non-equivalent control group pretest-posttest design was used. Participants were assigned to the experimental group (n=28) or control group (n=28). Contents of the program developed in this study included provision of information about internet addiction, interventions for empowerment and methods of behavioral modification. A pre-test and two post-tests were done to identify the effects of the program and their continuity. Effects were testified using Repeated measures ANOVA, simple effect analysis, and Time Contrast. Results: The self-regulation of the experimental group after the program was significantly higher than the control group. The score for internet addiction self-diagnosis and the internet use time in the experimental group were significantly lower than the control group. Conclusion: The effects of the integrated internet addiction prevention program for preventing internet addiction in elementary students at risk for internet addiction were validated.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.5
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• pp.345-351
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• 2018

A distributed control method is proposed to improve the power sharing performance of bidirectional distributed generators and the voltage regulation performance of a DC bus in a DC microgrid. Voltage sensitivity analysis based on power flow analysis is conducted to analyze the structural characteristics of a DC microgrid. A distributed control method using a voltage sensitivity matrix is proposed on the basis of this analysis. The proposed method uses information received through the communication system and performs the droop gain variation method and voltage shift method without additional PI controllers. This approach achieves improved power sharing and voltage regulation performance without output transient states. The proposed method is implemented through a laboratory-scaled experimental system consisting of two bidirectional distributed generators, namely, a load and a non-dispatchable distributed generator in a four-bus ring-type model. The experimental results show improved power sharing accuracy and voltage regulation performance.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.391-394
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• 1996

The effects of time-sampling on nonlinear output regulation problem is investigated. Output regulatedness is preserved under time sampling as in linear systems, however output regulatability is not robust with respect to time-sampling, and thus one needs to seek an approximate nonlinear sampled-data output regulator.

• Solar Energy
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• v.20 no.1
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• pp.1-9
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• 2000

Wind turbine system converts wind energy into electric energy. Since the velocity of wind is random in nature, control of the angular velocity of the blade is necessary in order to generate high quality electric power. The control of a blade can be divided into a stall regulation and a pitch control types. The stall regulation type which is based on the characteristics of an aerodynamic stall of the blades is simple and cheap, but it suffers from fluctuation of the resulting power. Or the contrary, pitch control type is based on the fact that the torque of the blade can be changed by varying the pitch angle of the blade. It is mechanically and mathematically complicated, but the control performance is better than that of the stall regulation type. This paper suggests a method of denying a mathematical modeling of the wind turbine system, and develops a speed control algorithm by pitch control. The validity of the algorithm is demonstrated with the results produced through sets of simulation.

• Korean Journal of Childcare and Education
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• v.12 no.3
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• pp.61-78
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• 2016

The current study examined the relations among teachers' beliefs, behavioral self-regulation and school readiness of preschoolers. The study sample included 229 preschoolers aged 3 to 5 attending child care centers located in Seoul and Gyeonggi area of Korea. Using Structural Equation Modeling, the paths from teachers' beliefs to children's school readiness via the mediation of their behavioral self-regulation were examined. Children's self-regulation was directly assessed using Head-to-Toe Tasks. The results showed that teachers' stronger beliefs in and responsibility for children's self-regulation and interpersonal skills significantly predicted greater behavioral self-regulation among children, which in turn, significantly influenced greater social skills and work-related skills. The contribution of teachers' beliefs and behavioral regulation to social skills and work-related skills was positive and stronger for boys.

• Journal of Power Electronics
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• v.17 no.6
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• pp.1469-1479
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• 2017

Primary-side regulation (PSR) scheme is widely applied in low power applications, such as cell phone chargers, network adapters, and LED drivers. However, the efficiency and standby power requirements have been improved to a high standard due to the new trends of DOE (Department Of Energy) Level VI and COC (Code Of Conduct specifications) V5. The major drawbacks of PSR include poor regulation due to inaccurate feedback and difficulty in acquiring acceptable regulation. A novel adaptive blanking strategy for constant current and constant voltage regulation is proposed in this paper. An accurate model for the sample blanking time related to transformer leakage inductance and the metal-oxide-semiconductor field-effect transistor (MOSFET) parasitic capacitance is established. The proposed strategy can achieve accurate detection for ultra-low standby power. In addition, numerous control factors are analyzed in detail to eliminate the influence of leakage inductance on the loop stability. A dedicated controller integrated circuit (IC) with a power MOSFET is fabricated to verify the effectiveness of the proposed control strategy. Experimental results demonstrated that the prototype based on the proposed IC has excellent performance.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.2031-2042
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• 2017

In this paper, a novel traffic flow control method based-on ramp metering and speed regulation using an adaptive sliding mode control (ASMC) method along with a deadzoned parameter adaptation law is proposed at a stochastic macroscopic level traffic environment, where the influence of the density and speed disturbances is accounted for in the traffic dynamic equations. The goal of this paper is to design a local traffic flow controller using both ramp metering and speed regulation based on ASMC, in order to achieve the desired density and speed for the maintenance of the maximum mainline throughput against disturbances in practice. The proposed method is advantageous in that it can improve the traffic flow performance compared to the traditional methods using only ramp metering, even in the presence of ramp storage limitation and disturbances. Moreover, a prior knowledge of disturbance magnitude is not required in the process of designing the controller unlike the conventional sliding mode controller. A stability analysis is presented to show that the traffic system under the proposed traffic flow control method is guaranteed to be uniformly bounded and its ultimate bound can be adjusted to be sufficiently small in terms of deadzone. The validity of the proposed method is demonstrated under different traffic situations (i.e., different initial traffic status), in the sense that the proposed control method is capable of stabilizing traffic flow better than the previously well-known Asservissement Lineaire d'Entree Autoroutiere (ALINEA) strategy and also feedback linearization control (FLC) method.

• Korean Journal of Adult Nursing
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• v.19 no.3
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• pp.339-352
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• 2007

Purpose: The purpose of this study was to investigate the effect of weight control program on body composition(body mass index and waist-hip ratio), blood pressure, serum lipids(total cholesterol, triglyceride, high density lipoprotein and low density lipoprotein) and self-regulation behavior in obese college women. Methods: Forty seven obese subjects were divided into experimental(22) and control(25) groups. The weight control program lasting 12 weeks consisted of a traffic-light diet, jumping-rope exercises, and behavior modification methods with e-mail counseling. The data were collected from 29 March to 17 September of 2004. The variables were assessed before and after intervention for 12 weeks in two groups. Then, those were repeated after a 12 week suspension of intervention in the experimental group. The data were analysed by the SPSS computer program. Results: BMI, HDL, LDL and self-regulation behavior levels showed significant differences between the experimental and control groups. While there were no significant differences in waist-hip ratio, blood pressure, total cholesterol and triglyceride. Conclusion: The weight control program had a positive effect on obese college women, and can be used to control obesity.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.2125-2133
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• 2018

To achieve high performance speed regulation, a robust adaptive speed controller is proposed for the permanent magnet synchronous motor (PMSM) subject to parameter uncertainties and input saturations in this paper. A nonlinear adaptive control is introduced to compensate the PMSM speed tracking errors due to uncertainties, disturbances and control input saturation constraints. By combining the adaptive control and the nonlinear robust control based on the interconnection and damping assignment (IDA) strategy, a new robust adaptive control is designed for speed regulation of PMSM. Stability and robustness of the closed-loop control system involved with the constrained control inputs rather than unconstrained control inputs are validated. Simulations for PMSM control in the presence of uncertainties and saturations nonlinearities show that the proposed approach is effective to regulate speed, and the average tracking error using the proposed approach is at least 32% smaller than the compared methods.

• The Korean Journal of Elementary Counseling
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• v.6 no.1
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• pp.247-268
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• 2007

This thesis aims to examine the influences of self-regulatory group counseling on self-regulation and school life satisfaction of the higher grade students in Elementary school. To achieve this aim, the following research questions were posed: First, What kind of influence does the self-regulatory group counseling have on the self- regulation of the higher grade students in Elementary school. Second, What kind of influence does the self-regulatory group counseling have on school life satisfaction scale of the higher grade students in Elementary school. In order to verify these research questions, the self-regulation test and school life satisfaction scale were conducted to both the experimental group and control group in pre-test, next, self-regulatory group counseling was practiced to the experimental group. And finally, a post-test was given to both the experimental group and control group. For this study, 200 students from 6th-grader of S Elementary school located in Incheon were given the self-regulation test and chosen 50 students who received low marks. Then, 50 students were researched into the school life satisfaction scale and chosen 16 students who got average-below score again. It was two matching groups through consideration of their score of the school life satisfaction scale, 8 students were arranged to the experimental group and the rest to the control group. The Self-Regulatory Group Counseling program developed by Eun Hyuck-gi(1999). The program was based on the following three programs: "The development. of the Cognitive-Behavioral Counseling therapy and their reports" by Kim HyeSuk(1996), Group counseling" by Brigman and Early(1991) and the study on the improving program in human relation" by Park KyeongAe(1998). The Self-Regulatory Group Counseling program activity was conducted during 6 weeks. Each session was 60 minutes and it continued for 8 sessions. The data collected to find out a difference in self-regulation and the degree of school life satisfaction between the experimental and control groups were processed by means of SPSSWIN program, and the post-test between both the groups were comparatively analyzed through t-test, a mean difference test. The following conclusions were drawn from the results of this study. First, the self-regulatory group counseling program has obvious effect of improving the self-regulation of the higher grade students in Elementary school. Second, the self-regulatory group counseling program has obvious effect of improving the school life satisfaction of the higher grade students in Elementary school. Particularly, this study shows statistical significance in cognitive facts of the self-regulation and the degrees of satisfaction with general school life, teacher, friend and facilities. Since the self-regulatory group counseling program has positive effects on self-regulation and satisfaction with their school life, It is required to utilize the structured self-regulatory group counseling program in school more widely to help students.