• Journal of Power Electronics
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• v.14 no.4
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• pp.632-640
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• 2014

For low-power high-frequency LED driver applications in small form factor mobile products, a high-efficiency boundary conduction mode tapped-inductor boost converter is proposed. In the proposed converter, the switch and the diode achieve soft-switching, the diode reverse-recovery is alleviated, and the switching frequency is very insensitive to output voltage variations. The circuit is quantitatively characterized, and the design guidelines are presented. Experimental results from an LED backlight driver prototype for a 14 inch notebook computer are also presented.

• Journal of Gifted/Talented Education
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• v.20 no.1
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• pp.1-30
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• 2010

The purpose of this study was to develop the inspection model of cognitive ability to identify visual artistic giftedness of the elementary school children with considering the relation between visual artistic giftedness and cognitive ability based on literature and preceding research. The research method applied literature research and quantitative research. Through literature review on the relation between art education and cognitive thinking and visual artistic of giftedness, it was suggested to prescribe the validity of cognitive ability as an element for identification of visual artistic giftedness identification, and then prescribed the elements of cognitive ability, and developed the inspection model of cognitive ability by measuring specific variables. Based on the results of literature research through the quantitative research, verified significance of developed inspection instrument on cognitive ability, validity and reliability of the inspection model of cognitive ability according to visual artistic giftedness identification of the elementary school children. As a result of reviewing related literature and preceding research, it could be referred that visual thinking ability, spatial perception power and critical thinking ability coincided with a characteristic of an art field can show excellent ability in various art activities and be valid criteria of visual artistic giftedness as cognitive ability of the visual artistic gifted with potential possibilities. In conclusion, as the elements of cognitive ability for the visual artistic giftedness identification of the elementary school children, visual thinking ability, spatial perception power and critical thinking ability were verified to be valid in terms of logical and experimental. Therefore, the result of the research will be able to provide a new approach in education program development of visual artistic giftedness of the elementary school children and a various developmental possibility in identification of visual artistic giftedness.

• Journal of Fashion Business
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• v.17 no.5
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• pp.1-13
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• 2013

The purpose of this study is to examine the power images in the style of a leader: through the focus on the portrait of Henry VIII. Study methods on the literature concerning viewpoints of power and image in the early modern age and the subjects of power are being used for theoretical backgrounds; and the visual data from National Portrait Gallery, British Library and the internet are used for exploratory studies. The results of this study are as follows. First, from the style of Henry VIII who represented the image of political power, the modern political phenomenon can be defined. Such phenomenon which displays images of political leaders from the study indicate an effective strategy. Second, the religious, a diplomatic representation for the style of Henry VIII powers, such as costume style and somatic visual images, represents the dignity and power by delivering visible internal attributes. Thus, the role model recognized by the society and the public's perception of leadership style affects the acknowledgement and belief by the people.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8C
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• pp.1193-1202
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• 2004

While the management of digital contents is getting more and more important, many researchers have studied about scene change detection algorithms to reduce similar scenes in the video contents and to efficiently summarize video data. The algorithms using histogram and pixel information are found out as being sensitive to light changes and motion. Therefore, visual rhythm gets used in recent work to solve this problem, which shows some characteristics of scenes and requires even less computational power. In this paper, a new scene detection algorithm using visual rhythm by direction is proposed. The proposed algorithm needs less computational power and is able to keep good performance even in the scenes with motion. Experimental results show the performance improvement of about 30% comparing with conventional methods with histogram. They also show that the proposed algorithm is able to keep the same performance even to music video contents with lots of motion.

• Korean Institute of Interior Design Journal
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• v.23 no.2
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• pp.166-173
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• 2014

This study analyzed visual-perceptual centrality as a measure to solve the confusion that might occur in visitor's movement in analyzing contemporary museums that have recently expand. Also, this study proposed a new methodology to understand the relationships of the occurrence and convergence of visual-perceptual power. The existing visibility graph analysis mostly ends up in identifying nodes corresponding to the physical environment of museums while the newly proposed visibility graph analysis is a methodology that can analyze the landmark on which the visual-perceptual power occurs and converges, by setting visible space elements as analysis variables, which showed a possibility to draw more reliable results in parallel to the existing analysis, and the results of this analysis are as follows. A public museum located in downtown has a limitation that it cannot but be multi-layered as a way to enlarge for the accommodation of a variety of programs on a limited site. Also, this study found that the problem of visitor orientation occurring in the multi-layer process was solved by a major space which was visual-perceptually void. Also, its types can be summarized into two types: One is setting parameter spaces (ramps, staircases, hallways) linked visual-perceptually to the major space and the other is solving the confusion of the visitor's movement by composing a simple exhibition space. In particular, it is judged that the type solving the confusion of the visitor's movement by composing a simple exhibition space also had a relationship with changes in the characteristics of the exhibited works by period. In addition, it was found that the entrance also appeared in two types: dependent type and independent type in the major space according to the characteristics of the major space.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.187-193
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• 2015

Purpose: This study was aimed to investigate effects of increased breath alcohol concentration (BrAC) which is the standard measurement of alcohol consumption in sobriety test under current laws on visual acuity and values of objective refraction. Methods: For twenty three males in 20s (average age $21.17{\pm}2.19$ years, body mass index (BMI) $22.09{\pm}2.16$) were selected. Distance and near visual test was performed at BrAC of 0%, 0.05% and 0.08%, and objective refraction with open-field auto-refractometer was also performed at different BrAC. Results: As breath alcohol concentration is increased, distance visual acuity was decreased, which was statistically significant, but near visual acuity was not changed. Also, values of objective refraction tended to be increased towards minus as breath alcohol concentration is increased. Conclusions: As breath alcohol concentration is increased, corrected visual acuity is decreased and refractive power is towards minus, it is necessary that visual acuity test and refraction measurement should be conducted under sober condition.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.71-73
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• 2018

일반적인 무선 전력 전송에서는 송신부와 수신부의 무선통신을 통하여 전력전달을 제어하나, TV와 같이 배터리가 없어 수신부의 통신모듈의 동작 대기가 어려운 전자 제품에는 적용하기 힘들다. 따라서 본 논문에서는 송신부와 수신부의 공진기를 LLC 트랜스포머 기반으로 설계하여 송/수신부간의 무선통신이 없는 근접 무선전력 전송 시스템을 제안하고자 한다. 제안하는 시스템에서는, 공진 주파수 근처의 설계된 주파수로 동작을 시켜, 수신기의 최소한의 저전압 보호 회로만으로도 약속된 기기간에 전력을 안정적으로 전달 할 수 있다.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.113-117
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• 2008

Purpose: This study is to survey that uncomfortable feeling of visual acuity in the first wearing glasses, the number of visiting in age, above vision ranging and refractive errors, astigmatism, and anisometropia. Methods: Automatic refraction and naked visual acuity test executed to receive prescription glasses that the man 509 and women's 499 people visited for the first time, among 3~15 years old who visited an ophthalmoiogical hospital, from January to December, 2003. Results: The first wearing glasses started 3 years old and the most cases was 8~9 years old when they were visited visual acuity 0.5 to 0.7 in most cases. Refractive errors appeared 8 years old and its most plentifully with 20.4%, 92.2% was myopia and 5.2% was hyperopia for the man. Also cases of women was 91.9% for myopia and 5.1% for the hyperopia. Spherical equivalent power was S-1.50${\pm}$1.10D and appeared 62.3% for the low myopia. Astigmatism was appeared 44.6% for the with the rule astigmatism and 75% was cylinder power lower than 1.00D. Cases of simple astigmatism need to glass when was cylinder power C-1.37${\pm}$1.01D, and C-0.50D appeared most distribution. More than 2.00D anisometropia appeared 2.3% for the whole subjective. Conclusions: Of the first wearing glasses visual acuity is 0.5~0.7, spherical equivalent power is S-1.50${\pm}$1.10D, cylinder power of simple astigmatism is C-1.37${\pm}$1.01D.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.83-85
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• 2018

저전력에 사용되는 Flyback 컨버터에서는 일반적으로 트랜스포머의 보조권선을 통하여 구동 IC에 필요로 하는 전력을 공급한다. 하지만, USB PD와 같이 5~20V의 넓은 출력전압을 가지는 경우 IC Vcc 정격 전압을 위하여 Linear regulator 사용이 필수적이나, 이는 소자발열 및 시스템 효율을 저하시킨다. 따라서, 본 논문에서는 출력전압 변동에 따라 변압기의 보조권선을 변환 시키는 회로를 제안하고자 한다.

• Journal of the Korean Society of Safety
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• v.24 no.2
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• pp.48-54
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• 2009

Structures to support against slop failures or resist earth pressure like masonry retaining walls or retaining walls have continued to advance and evolve to new eco-friendly, easy-to-construct, crib retaining walls with varied forms and construction methods, meeting the needs of the times. Researches until now, however, have focused on the analyses of site displacement or stability of the whole site including structures like retaining walls, and thus, researches on rational design or method for stability analysis are lacking. Therefore, this study was conducted on a number of stability analyses, such as the visual power line or stability on sliding, being presented for bin walls, which enable vegetation to grow and were developed and applied in varied forms, meeting the development demands for eco-friendly retaining wall structures. This study compared the results of stability analyses, determined their feasibility, and evaluated their stability according to the height and facade slope of retaining walls. According to the results of this study, traditional masonry retaining wall analysis showed rather conservative stability evaluation results in the stability evaluation of bin walls, and the method using the visual power line seems to be objective because it produced similar results to the stability evaluation method on sliding or turnover.