• Journal of Power Electronics
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• v.16 no.6
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• pp.2294-2305
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• 2016

The introduction of a high-voltage direct-current (HVDC) system based on a modular multilevel converter (MMC) for wind farm integration has stimulated studies on methods to control this type of converter. This research article focuses on the control of the AC voltage and circulating current for a wind-farm-side MMC (WFS-MMC). After theoretical analysis, emotional learning (EL) controllers are proposed for the controls. The EL controllers are derived from the learning mechanisms of the amygdala and orbitofrontal cortex which make the WFS-MMC insensitive to variance in system parameters, power change, and fault in the grid. The d-axis and q-axis currents are respectively considered for the d-axis and q-axis voltage controls to improve the performance of AC voltage control. The practicability of the proposed control is verified under various conditions with a point-to-point MMC-HVDC system. Simulation results show that the proposed method is superior to the traditional proportional-integral controller.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.2
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• pp.69-81
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• 2020

The objective of this study is to seek ways to maximize learning effects from e-learning by drawing improvement directions through investigating and analyzing an awareness of e-learning among e-learning attendees. The study was conducted among the attendees who are taking the e-learning program operated by K University and collected data from the students taking second semester in 2018 with the use of structured questionnaires. For data processing, SPSS Statistics 22.0 and AMOS were used, along with such analytical methods as frequency anslysis, descriptive statistical analysis, ANOVA (Analysis of Variance), t-analysis and cross tabulation. For significant data, it conducted an analysis by carrying out the Scheffe's test. According to the findings from this study, they showed a significant difference only in gender and curriculum desired to be opened in the question about e-learning participation motives per background factor. As for the learners' motives to study, it was confirmed that they tend to become more biased on time utilization and convenience of learning methods. The analysis of which factor of the three - learning factors, system factors and instructor's factors - has greatest effects on learning satisfaction indicated that learning factors influenced learning satisfaction the most in accordance with values for non-standard coefficient beta, followed by instructor factors which had a direct effect.

• Educational Technology International
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• v.13 no.1
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• pp.101-144
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• 2012

Students mostly precede their learning without any direct support of instructor in e-learning and mobile educational environment. Many useful strategies and tools to facilitate self-regulated learning behaviors in e-learning environment have been introduced, yet, the limit has been reached by only suggesting self-regulated strategies with visual information in the most researches. Accordingly, this research is intent to propose the sound design strategies that facilitate learner's self-regulated learning behaviors in mobile learning environment. To achieve the objective of the research, two research questions are presented. First, what are the sound design strategies that facilitate the self -regulated learning behaviors in mobile learning environment?. Second, what are the results of evaluating the developed sound design strategies in terms of facilitating self-regulated learning behaviors?. To solve these research questions, the literature reviews on characteristics of mobile learning, concepts and features of self-regulated learning and sound were done to establish the sound design strategies. Through formative research method targeting instructional designers, sound design strategies were modified and supplemented. The research to validate these was performed and to verify the effect of the derived sound design strategies, the usability test aimed at instructional designer and learners was conducted. The final sound design strategies through this research process were six general design strategies and the sixteen detailed strategies. This research is meaningful because this offers the basic research on sound information design which has been lacking and help upgrade the upper limit of instructional design which mainly focused on visual information in mobile learning environment that shows information in a small screen.

• Journal of Internet Computing and Services
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• v.13 no.2
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• pp.119-126
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• 2012

The purpose of this study is to test the motivations for e-Learning service usage of smart device users. To do this, empirical data were collected by conducting a field survey with 382 smart-device based e-learners, and structural equation model was used for the purpose of analyzing the data acquired by the survey. A structural equation model was designed and constructed by such factors like usefulness, enjoyment, word-of-mouse(WOM) effect, and social interaction on e-Learning usage intention. In addition, social interaction has an influence on WOM effect. The results of the analysis are summarized as follows; first, usefulness, enjoyment, and WOM have direct effects on e-Learning usage intention. Second, social interaction not only has direct influence on e-Learning usage intention but also has indirect influence carried by WOM effect. The findings have significant implications which the study inquires into the factors for e-Learning usage motivations of smart-device based e-learners.

• Journal of The Korean Association For Science Education
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• v.27 no.5
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• pp.412-420
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• 2007

In this study, we investigated the influences of the epistemological beliefs on the conceptual change processes in respects of cognitive conflict, situational interest, attention and state learning strategies. After administering epistemological belief questionnaire as a pretest, 218 seventh graders possessing misconceptions about density were selected from the results of a preconception test. The questionnaires of responses to a discrepant event and situational interest were administered. After learning with a CAI program, attention test, state learning strategy test and conception test were also administered as post-tests. Analysis of the results revealed that fixed ability, quick learning and certain knowledge, which are epistemological factors, were highly related, but only certain knowledge exerted a direct effect on conceptual understanding negatively. It also had positive effects on attention directly as well as via situational interest, and thus increased conceptual understanding, even if the effects were relatively smaller than the direct effect. However, epistemological beliefs had little influence on conceptual understanding through cognitive conflict and/or state learning strategies.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.5
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• pp.25-32
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• 1996

This paper will propose the direct adaptive learning control scheme based on adaptive control technique and intelligent control theory for a nonlinear system. Using the proposed learning control scheme, we will apply to on-line control an uncertain but for model perfect matching, it's structure condition is known. The effectiveness of the proposed control schem will be illustrated by simulations of a robot manipulator.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.697-702
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• 1994

This paper illustrates a new learning control for robot manipulators using Lyapunov direct method. It has been shown that under the proposed learning control robot manipulators are always guaranteed to be asymptotically stable with respect to the number of trials. The proposed control is also robust in the sense that the exact knowledge of the nonlinear dynamics is not required except for bounding functions on the magnitude.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.186-189
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• 1990

The automization of manufacturing lines may be accomplished by replacing the human operator with computer system. This paper describes an idea to fully automize the razor qrinding process. Now, in this system, to control the process, human operator must estimate the qrinded states and control the grinding machine continuously. We propose two methods to automize this process by using CMAC memory. One is about learning expert-rules without direct communication with operator. And the other is complete self-learning method based on CMAC's learning algorithm. These ideas may be applied for another manufacturing processes.

• Education of Primary School Mathematics
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• v.3 no.2
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• pp.109-113
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• 1999

To improve the elementary student's ability to classify the data and obtain the information from the data through graphics, it is necessary to use the teaching and learning material which encourage the student to study with interest and is adjacent to the student's environment. In this thesis. several materials to satisfy the condition is proposed together with some remarks to direct the teaching. These materials is recommended to use for the maturity learning and teaching in grade 6.

• Korean Journal of Child Studies
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• v.30 no.5
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• pp.23-39
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• 2009

This study examined influences of teacher's transformational leadership, and their trust and empathic understanding on children's learning motivation. Participants were 513 $5^{th}$ and $6^{th}$ graders from Seoul, Buchon and Inchon. Data were collected via questionnaires and analyzed by descriptive statistics, Pearson's correlation, and multiple regression analysis. Results showed that (1) Teacher's transformational leadership, trust and empathic understanding were positively related to children's learning motivation. (2) Teacher's transformational leadership was the strongest predictor for children's learning motivation. (3) Teacher's transformational leadership had a direct influence on children's learning motivation empathic understanding mediated between teacher's transformational leadership and children's learning motivation.