• Korean Journal of Optics and Photonics
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• v.22 no.1
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• pp.23-29
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• 2011

Bistable chiral splay nematic liquid crystal display (BCSN LCD) is a memory type liquid crystal display using splay and $-\pi$ twist states as two stable states. When the cell thickness to pitch (d/p) ratio is 0.25, splay and $-\pi$ twist states have permanent memory time. However, when the transition from $-\pi$ twist state to splay state is caused by a fringe field, pixel regions show that the splay state is not perfect, but rather includes a contribution from the $-\pi$ twist state. In this paper, we propose a reflective BCSN LCD using $-\pi$ twist state in which the two stable states do not coexist. The fabricated reflective BCSN LC cell shows a high contrast ratio of over 30:1 and response times of 950 ms and 450 ms in vertical and fringe field switching, respectively. The proposed cell also shows wide viewing angle characteristics of $180^{\circ}$ in left- and right directions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11A
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• pp.1827-1840
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• 2001

In digital data transmission/storage systems, the compensation for channel distortion is conducted normally using a training sequence that is known a priori to both the sender and receiver. The use of the training sequences results in inefficient utilization of channel bandwidth. Sometimes, it is also impossible to send training sequences such as in the burst-mode communication. As such, a great deal of attention has been given to the approach requiring no training sequences, which has been called the blind equalization technique. On the other hand, to utilize the limited bandwidth effectively, the concept of partial response (PR) signaling has widely been adopted in both the high-speed transmission and high-density recording/playback systems such as digital microwave, digital subscriber loops, hard disk drives, digital VCRs and digital versatile recordable disks and so on. This paper is concerned with blind adaptive equalization of partial response channels whose transfer function zeros are located on the unit circle, thereby causing some problems in performance. Specifically we study how the problems of blind channel equalization associated with the PR channels can be improved. In doing so, we first discuss the existing methods and then propose new structures for blind PR channel equalization. Our structures have been extensively tested by computer simulation and found out to be encouraging in performance. The results seem very promising as well in terms of the implementation complexity compared to the previous approach reported in literature.

• Journal of vocational education research
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• v.35 no.6
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• pp.21-38
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• 2016

The purpose of this study is to analyze an experience of field practice perceived by vocational teachers. Data for analysis were collected from 689 vocational teachers who participated in the training at the Center for in-service teacher education in the School of Agriculture and Life Sciences, Seoul National University and at the Center for in-service teacher education of Chungnam National University. After screening, 685 responses were used in the analysis. As a result, it turned out that only 112 vocational teachers(16.5%) participated in the field practice for more than 4 weeks when they were in pre-service education. However, vocational teachers seemed to perceive that experience of field practice was generally required in pre-service education(average 4.07). In-depth questionnaire was conducted on 143 respondents who replied that they participated in field practice program for more than 4 weeks and those who participated in the program for less than 4 weeks but completed the paperwork. Most of vocational teachers who participated in field practice were placed in small and medium sized enterprises, stayed at home or relatives' home and commuted by the bus or subway. In this research, 34.8% of the vocational teachers who participated in field practice received financial compensation and 80.3% of the teachers got credit recognition. The perception of satisfaction on field practice program was found to be moderate(average 3.51).

• Journal of The Korean Association For Science Education
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• v.43 no.3
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• pp.307-319
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• 2023

This study aims to explain the key concepts and principles of text-based generative artificial intelligence (AI) that has been receiving increasing interest and utilization, focusing on its application in science education. It also highlights the potential and limitations of utilizing generative AI in science education, providing insights for its implementation and research aspects. Recent advancements in generative AI, predominantly based on transformer models consisting of encoders and decoders, have shown remarkable progress through optimization of reinforcement learning and reward models using human feedback, as well as understanding context. Particularly, it can perform various functions such as writing, summarizing, keyword extraction, evaluation, and feedback based on the ability to understand various user questions and intents. It also offers practical utility in diagnosing learners and structuring educational content based on provided examples by educators. However, it is necessary to examine the concerns regarding the limitations of generative AI, including the potential for conveying inaccurate facts or knowledge, bias resulting from overconfidence, and uncertainties regarding its impact on user attitudes or emotions. Moreover, the responses provided by generative AI are probabilistic based on response data from many individuals, which raises concerns about limiting insightful and innovative thinking that may offer different perspectives or ideas. In light of these considerations, this study provides practical suggestions for the positive utilization of AI in science education.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.55-62
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• 2012

This study is a survey of regulatees' perception on main contents and enforcement effect of the Act, the retailers at food stores within Green Food Zone, for the effective enforcement of "The Special Act on the Safety Management of Children's Dietary Life" legislated in 2008. Percentage, frequency analysis, and T-test are derived from the survey carried out to the 175 retailers at food stores within Green Food Zone, across the country except Jejudo, for the two months March and April of 2011. The survey results are as follows. Over 80% of the respondents are aware of comprehensive policy for child food safety and the enforcement of 'the Special Act' and considering the rate of satisfaction on food safety information provided by government, over 90% of the respondents, virtually most of them, are satisfied. The rate of awareness of Green Food Zone is about 80% and that of outstanding business for children is about 50%, showing little perception of it. The comparison of the survey result of 2011 with that of 2010, which have the same questions to the retailers within Green Food Zone, still indicates a need for enhancement of understanding on absolute standard, though it showed fairly better improvement in general. Several proposals are given in this study based on the survey results, which will contribute to the children food safety and health improvement in the end.

• Journal of the Korean Society for information Management
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• v.31 no.1
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• pp.251-275
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• 2014

This study conducted qualitative research to investigate the librarians' organizational commitment and relations between the commitment and their goal recognition in the university library context with several open-ended, deep interviews with university librarians in order to understand the relations from diverse perspectives. As a result, many participants showed low level of organizational commitment because of their hygiene factors, such as payment, incentives, relations with colleagues, and job conditions as well as motivators including characteristics of the work, sense of accomplishment, responsibility, promotion, and self-improvement. The two factors are considered to have direct impacts on their organizational commitment. Also, the research revealed that positive goal perception was related to motivators and, at the same time, hygiene factors. Accordingly, we concluded that librarians' perception of goals are closely related to both hygiene factors and motivators. We also identify that a need of a statistical study with a questionnaire survey to confirm the relations between the organizational commitment and goal perception for developing managerial measures for the organizational commitment, and further;for better library performance.

• Journal of Digital Convergence
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• v.16 no.8
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• pp.373-380
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• 2018

The purpose of this study was to know the effects of teaching behavior type of expression activity class on flow and competence in elementary school. The subject for this research consisted of elementary students located in Busan were selected as a population. The sampling method was convenience sampling out of non-probability sampling method. A total of 300 questionnaires were distributed and 280 copies were collected back. Out of those returned questionnaires, insincerely replied or double-replied questionnaires were excluded and finally 216 questionnaires were analyzed for this study. Collected data were put to frequency analysis, exploratory factor analysis reliability analysis, correlation analysis, and multiple regression analysis using the SPSS Win Ver. 22.0 program. The results of these analyses are as follows. First, the commanding type, the autocratic type, the democratic type and the reward type which are the subordinate variables of the teaching behavior type, were all found to have significant effects on the flow. Second, the democratic type and the reward type which are the subordinate variables of the teaching behavior type, were found to have significant effects on the competence. But, the commanding type and the autocratic type which are the subordinate variables of the teaching behavior type, were not found to have significant effects on the competence. Third, the flow were found to have significant effects on the competence.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.2 s.314
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• pp.63-73
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• 2007

This paper proposes an illuminant-adaptive reproduction method using light adaptation and flare conditions for a mobile display. Displayed images in daylight are perceived as quite dark due to the light adaptation of the human visual system, as the luminance of a mobile display is considerably lower than that of an outdoor environment. In addition, flare phenomena decrease the color gamut of a mobile display and de-saturating the chroma. Therefore, this paper presents an enhancement method composed of lightness enhancement and chroma compensation. First, the ambient light intensity is measured using a lux-sensor, then the flare is calculated based on the reflection ratio of the display device and the ambient light intensity. To improve the perceived image, the image's luminance is transformed by linearization of the response to the input luminance according to the ambient light intensity. Next, the displayed image is compensated according to the physically reduced chroma, resulting from flare phenomena. This study presents a color reproduction method based on an inverse cone response curve and flare condition. Consequently, the proposed algorithm improves the quality of the perceived image adaptive to an outdoor environment.

• Korean Security Journal
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• no.50
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• pp.265-283
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• 2017

The purpose of this study is to examine the effects of job stress on Organizational commitment and turnover intent with targets of Employees of Security Industry. A total of 156 answered questionnaires were used as final data. The following conclusions were obtained by conducting correlation analysis and multiple regression analysis using SPSS 18.0 statistical program. First, it is found that Organizational commitment effects some sub-factors of job stress such as inappropriate compensation, insufficient job control and job requirements. Second, it is found that turnover intent affects some sub-factors of job stress such as inappropriate compensation, insufficient job control and job requirements. Third, it is found that turnover intent affects Organizational commitment. Based on the result of the research, job stress seems to affect organizational commitment and people's decisions to change jobs. The two variables job stress and organizational commitment act as key factors in deciding whether to change jobs, while organizational commitment plays as an important parameter. In other words, there should be principles to do work along with channels through which workers communicate with each other. To this end, there need to be programs educating people to work together as well as systematic assistance and support to encourage people to develop their expertise.

• Journal of The Korean Association For Science Education
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• v.22 no.4
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• pp.892-905
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• 2002

There are an increasing emphasis on affective domain, for example interest or belief, in science education. But decreasing interest on learning science and tendency to avoid science-related job are serious problems of secondary science education, especially in case of vocational high school students. However there are few researches for vocational high school students. In this study, preference for science is assumed to be a multidimensional property that reveals ones' behavioral volition and valuation as well as emotional response upon learning science. To investigate vocational high school students' preference for science and its causal factors, a Likert style questionnaire was developed through factor analysis. Students' preference for science was analyzed by 3 categories, and its causal factors are investigated by path analysis using structural equation model.