• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.225-226
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• 2014

본 논문에서는 최악의 상황에서도 계통 연계형 태양광 발전 시스템에서의 단독운전 현상을 신속히 검출하여 시스템을 정지시킬 수 있게 하기 위해 Positive-feedback을 가지는 주파수 변동 기법에 대한 설계와 시뮬레이션을 바탕으로 단독운전 검출 성능 보장과 출력 전력의 품질 보장을 위한 제어기 설계 방법에 대하여 제시하고, 이를 시뮬레이션을 통해 타당성을 검증한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.2
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• pp.105-110
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• 2019

This study proposed a reactive power variation (RPV) method equipped with positive feedback (PF) for detecting the islanding operation of distributed generation systems. The proposed RPV consists of the constant reactive power component and a certain reactive power term and uses the frequency deviation between the rated and the measured frequencies. The constant reactive power is injected from distributed generation system and power factor is to 0.9975 in grid-connected operation. PF is activated from generation of the frequency deviation and the injected reactive power is continuously increased due to PF when islanding occurs. Consequently, the increasing reactive power causes the point of common coupling frequency to deviate from the maximum/minimum threshold level. Performance of the proposed RPV is verified in a 1.7 kW T-type inverter, and the detection times are 53 and 150 ms.

• English Language & Literature Teaching
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• v.9 no.2
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• pp.151-171
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• 2003

This paper critically reviewed the role of negative feedback in second language acquisition with a focus on recasts based on the findings of recent research investigating the effects of recasts on second language acquisition. First, recasts as negative feedbacks or negative evidence were reviewed in terms of Pinker's four criteria: the evidence of existence, availability, use, and necessity of recasts in second language acquisition. Second, the issue of the nature of recasts, whether they have benefits in SLA as a negative or positive evidence, was discussed with reference to Leeman(2003)'s research findings. Then, in relation to availability and use of recasts, the issue of the extent that they are noticed by learners was reviewed based on the findings from Philp(2003)'s study. Finally, the limitations of these two studies and the research orientation of future study were mentioned.

• Educational Technology International
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• v.12 no.2
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• pp.71-94
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• 2011

How can an automated essay scoring (AES) program, which provides feedback for essays, be a formative tool for improving ESL writing? In spite of the increasing demands for English writing proficiency, English writing instruction has not been effective for teaching and learning because of a lack of timely and accurate feedback. In this context, AES as a possible solution has been gaining the attention of educators and scholars in ESL/EFL writing education because it can provide consistent and prompt feedback for student writers. This experimental study examined the impact of different types of feedback for a college ESL writing program using the Criterion AES system. The results reveal the positive impact of AES in a college-level ESL course and differences between the teacher's feedback and the AES feedback. The findings suggest that AES can be effectively integrated into ESL writing instruction as a formative assessment tool.

• ETRI Journal
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• v.38 no.2
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• pp.235-243
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• 2016

A low-noise readout integrated circuit (ROIC) for a microelectromechanical systems (MEMS) microphone is presented in this paper. A positive feedback signal amplification technique is applied at the front-end of the ROIC to minimize the effect of the output buffer noise. A feedback scheme in the source follower prevents degradation of the noise performance caused by both the noise of the input reference current and the noise of the power supply. A voltage booster adopts noise filters to cut out the noise of the sensor bias voltage. The prototype ROIC achieves an input referred noise (A-weighted) of -114.2 dBV over an audio bandwidth of 20 Hz to 20 kHz with a $136{\mu}A$ current consumption. The chip is occupied with an active area of $0.35mm^2$ and a chip area of $0.54mm^2$.

• Journal of the Korea Safety Management & Science
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• v.24 no.3
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• pp.61-74
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• 2022

In a rapidly changing environment, it is essential for companies to develop their capabilities for sustainable growth. To this end, informal learning at work plays an important role for small and medium-sized enterprises that are having difficulties in human resource development. If the GRIT of workers and the spiritual leadership of leaders are maintained at an appropriate level, the effect of informal learning will increase. This study derived the following results through a survey of workers participating in the Work-learning Dual System in Korea. First, experience and feedback among informal learning activities have a significant positive effect on competency development. Second, the higher the level of the GRIT of workers, the greater the magnitude of the positive effect of experience and feedback on competency development, showing a positive moderating effect. Third, in the case of workers with high GRIT, capacity development is strengthened as experience or feedback increases, and the higher the level of spiritual leadership, the greater the scope of reinforcement. On the other hand, it can be seen that in the case of workers with low GRIT, competency development weakens as experience or feedback increases, and the higher the level of spiritual leadership, the greater the extent of the weakening.

• Clinical and Experimental Reproductive Medicine
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• v.7 no.1_2
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• pp.3-10
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• 1980

Pituitary gonadotropes, as target cells, exhibit cyclic changes in terms of LH and FSH release in synchrony with the estradiol levels. The ultimate release is determined by the relative size of the two pools of gonadotropins, which is regulated by the two controllers: LH-RH and estradiol. LH-RH appears to serve as a primary drive on the gonadotrope, stimulating gonadotropin synthesis, storage, and release. Estradiol amplifies the action of LH-RH and induces the development of a self-priming effect of LH-RH except that it impedes LH-RH mediated gonadotropin release. Negative and positive feedback action of estradiol is revealed to operate by different mechanisms. The pituitary capacity increases severalfold from early to late follicular phase, which is considered to be prerequisite for the development of mid-cycle surge. CNS-hypothalamic dopamine, norepinephrine, and prostaglandins, as well as LH-RH, are involved in the negative and positive feedback effects of estradiol. The possible mechanisms in the triggering of LH-RH release for the initiation of midcycle LH-RH surge are considered.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.9-15
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• 2021

The current study examined the cyber learners' perceptions of the educational usefulness of Grammarly, an online grammar checker, after it was used to provide feedback to cyber university students in a situation where the instructor could not provide sufficient feedback on their written work in English. The survey results, revealed that the majority of learners had positive attitudes to the usefulness of Grammarly. In particular, the feedback immediately available whenever needed was regarded as helpful in improving English sentences, and most learners were highly satisfied with the amount of the feedback provided by Grammarly. It was also found that Grammarly had positive effects in terms of the affective domains, helping learners to improve their interest and confidence in English writing. In particular, Grammarly was found to be effective in reducing writing anxiety in English, one of the main factors negatively affecting writing performance in English. However, along with these positive results, limitations such as inaccurate feedback and inadequate explanation of errors were also found. Therefore, when Grammarly is used for English education, it is necessary to conduct multifaceted research to develop effective teaching methods that can minimize the problems that may arise from these limitations.

• PNF and Movement
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• v.9 no.1
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• pp.11-19
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• 2011

The purpose of this study was to investigate whether it makes difference to use of the Augmented Feedback Type(Verbal Feedback, VTR Feedback and Verbal & VTR Feedback) to hemiplegic adults on learning of motor skill. For the purpose 15 hemiplegic adults who are received rehabilitation program at H hospital in Hong-Sung, Choong-Nam Province. Subjects were classified into three groups by random assignment; the Verbal Feedback group, the VTR Feedback group and Verbal & VTR Feedback group. Each groups received 5 subjects from hemiplegic adults. Subjects were tested by Timed Up and Go test for 9 weeks. And to find out the improvement measured by Pre-Test, Acquisition Test and Retention Test. To find out the improvement of each group's measures took average and standard deviation. To probate the significance of difference between the improvement conducted the one-way ANOVA and to probate the significance of difference of Acquisition Test and Retention test conducted paired t-test. The results of this study were as follows; First, All of Augmented Feedback Types had a positive effect on hemiplegic adults to learning of motor skill. Second, The Verbal Feedback group and the VTR Feedback group had no significantly difference at Acquisition Test, But They had the most improvement at Retention Test. Third, In hemiplegic adults, the Verbal & VTR Feedback group had the highest Retention Effect.

• Korean System Dynamics Review
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• v.15 no.4
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• pp.101-127
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• 2014

This study aims to understand how and why each stage of capitalism grows and changes into the new direction in the moment of crisis, based on the systems thinking approach through the causal loop feedback structure. To achieve the research purpose, it classifies the evolution process of the capitalistic economic system into 4 types: Capitalism 1.0(Classical Laissez-Faire Capitalism), 2.0(Revised Capitalism), 3.0(Neo-liberalism), and 4.0(New Capitalism for the Future). This study focuses particularly on by which feedback structure the growth, crisis, and new transition of capitalism could be explained. The main research results are as follows. The intended positive feedback structure caused the growth at each early stage of capitalism. After that time, as a result of the uncontrolled growth, the negative feedback structure controlling its growth operated on the one hand, while the positive feedback structure amplifying the crisis did on the other hand. The study suggests the Resilient Capitalism as the new evolutional direction of Capitalism 4.0. It can contribute to strengthening its resilience by which all the economic players can recover promptly and flexibly from the crises such as the failure of competition and unemployment.