• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.65-69
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• 2004

The small form factor optical data storage devices are developing rapidly nowadays. Since it is designed for portable and compatibility with flash memory, its components such as disk, head, focusing actuator, and spindle motor should be assembled within 5 m thickness. The thickness of focusing actuator is within 2 mm and the total working range is $+/-100{\mu}m$, with the resolution of less than $1{\mu}m$. Since the thickness is limited tightly, it is hard to place the yoke that closes the magnetic circuit and hard to make strong flux density without yoke. Therefore, Halbach array is adopted to increase the magnetic flux of one side without yoke. The proposed Halbach array type focusing actuator has the advantage of thin actuation structure with sacrificing less flux density than conventional magnetic array. The optical head unit is moved on the swing arm type tracking actuator. Focusing coil is attached to swing arm, and Halbach magnet array is positioned at the bottom of deck along the tracking line, and focusing actuator exerts force by the Fleming's left hand rule. The working range and resolution of focusing actuator are analyzed with FEM and experiment.

• Journal of Biomedical Engineering Research
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• v.22 no.4
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• pp.321-330
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• 2001

In this paper, we propose a new synthetic aperture focusing scheme for improving the lateral resolution which is one of the most important factors determining the quality of ultrasound imaging. The proposed scheme enables full round-trip dynamic focusing with approximately limited property. This properties are obtained through transmitting plane waves of which the traveling angle varies with the receive subaperture position, as opposed to stepping the spherical wave source across an array in other synthetic aperture focusing schemes, and employing dynamic focusing in receive. In this paper, the properties of the proposed scheme is analyzed in which a hypothetical infinite line source is used to transmit the plane waves and verified through computer simulation results. Also, we show that the proposed scheme is realizable with an array transducer with a finite aperture size. In summary, it is shown through comparison between the field contours of the proposed scheme and the conventional scheme that the proposed scheme can improve greatly the lateral resolution of ultrasound imaging.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.04a
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• pp.380-384
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• 2000

Effectiveness of information conveyance in reading is affected by several factors such as line length, letter size, line spacing arrangement as well as typeface itself. This study examined relative importance of these factors by asking people to read the texts that was constituted with non-square form letter and rank the preference of texts through conjoint analysis. In the case of reading time, justification was the most important factor, followed by leading, line spacing, letter width, line length, font size, font type in their order of importance. And in the case of preference decision, letter width was the most important factor, followed by font size, justification, line spacing, leading, line length, font type. The result will be useful in understanding how to consider human preference in the hangul typography.

• Research in Mathematical Education
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• v.26 no.4
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• pp.271-289
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• 2023

This research investigates the development of elementary students' concepts of line segments, straight lines, and rays, employing metaphor analysis as a research methodology. By analyzing metaphorical expressions, the research aims to explore how elementary students form these geometric concepts line segments, straight lines, and lays and evolve their understanding of them across different grades. Surveys were conducted with elementary school students in grades three to six, focusing on metaphorical expressions and corresponding their reasons associated with line segments, straight lines, and rays. The data were analyzed through coding and categorization to identify the types in students' metaphorical expressions. The analysis of metaphorical expressions identified five types: straightness, infinity or direction, connections of another geometric concepts, shape and symbols, and terminology.

• Journal of Korea Society of Digital Industry and Information Management
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• v.17 no.4
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• pp.197-207
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• 2021

The threat of COVID-19 pandemic put many universities in Korea to develop and implement various types of non-face-to-face on-line classes, such as on-line real time class and on-line recorded video class. Online education has been recognized as one of the effective educational methods because of its ubiquitous and flexible educational environments. Even though COVID-19 led to many problems such as faculty's burden and stress during the early stage of COVID-19, both students and faculties have gradually become familiar with on-line environment. As students have got accustomed to the online environment, on-line recorded lectures are shown to be more preferred rather than on-line real time class. Researches regarding the learner's satisfaction of on-line classes during the COVID-19 indicate that systematic and good quality contents and interaction by instructor are important factors. This study, therefore, investigate the learner's satisfaction of online classes in Liberal Arts course using recorded video contents in terms of contents and interaction. The results of empirical analysis reveal that systematic and good quality contents are likely to predict learner's satisfaction and interaction plays a great role in providing those contents. These findings provide insights that preparing systematic contents and interaction are key to enhancing learner's satisfaction of on-line classes in Liberal Arts course.

• Journal of Information Technology Services
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• v.13 no.1
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• pp.103-124
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• 2014

Prior studies on knowledge sharing have concentrated primarily on either organizational or individual characteristics. However, by focusing on the interaction between members in On-line communities of practice (CoPs), we seek to identify and analyze factors that affect knowledge sharing by members in CoPs. Therefore, we examine if the independent variables such as interactivity, followership, and trust have positive impacts on the dependent variables such as commitment to CoPs and intention to share knowledge. In addition, this study also investigates the relationship between commitment to CoP and intention to share knowledge. The empirical results show that interactivity has a positive impact on commitment, but an insignificant impact on intention to share knowledge. Besides, trust between members is significantly associated with intention to share knowledge, whereas it does not have a significant effect on commitment. Moreover, followership is significantly related to both commitment and intention to share knowledge. These empirical findings show that the relationship between members in CoPs play a significant, positive role in intention to share knowledge. In conclusion, this research contributes to shedding a light into both interactions between members in and commitment to CoPs that are critical to facilitate knowledge sharing.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.5
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• pp.28-38
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• 2005

The De-militarized Zone(DMZ) on the Korean Peninsula is ecologically conserved and naturally developed as access to the area has been controlled in the past five decades. As a result, biodiversity and wetlands are developed very well, but they have not been sufficiently surveyed due to land mines and security reasons. Focusing on the Kyongui Line area in Paju DMZ, this study aims at examining the status of forested wetlands in detail through an on-site survey and understanding the features of forested wetlands in DMZ. The forested wetlands of Paju Kyongui Line area are inhabited by naturally grown Salix koreensis Andress. and Acer ginnale Maxim. and affected by Sacheon Basin region extensively. As the topography of this region is created of inundated area and gentle ground, it is easily affected by hydrology and irrigation and has ideal conditions as forested wetlands. In addition, forest wetlands in this area were used as agricultural land in the past but now transformed into palustrine forested wetlands after being deserted for long time. However, as construction of roads and railways increasingly blocks water paths, the coverage of Robinia pseudoacacia L. and Amorpha fruticosa L. is on the rise, which indicates that forestedwetlands are gradually becoming inland over time.

• Korean Journal of Human Ecology
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• v.11 no.1
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• pp.45-58
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• 2002

The purpose of this study was to offer a more functional slacks by analyzing its crotch length. The result of the study were as follows : Regarding the feeling of wearing and appearance, the P2 b style which measures the crotch length starting from the waist line passing around the iliac spine was the most highly evaluated. This suggested that the functionality of dance movement was more influenced by the position of the waist line not by the crotch length measurement. Since the front and rear center lines of the crotch could not be flown if the waist line of slacks was positioned high, both the crotch and abdominal part might be clogged or tightened when dancers made large dance movements or bended their upper bodies forward. In conclusion, slacks for more functional dance movement should be manufactured focusing on the location of the waist line rather than on the crotch length.

• The Research Journal of the Costume Culture
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• v.12 no.1
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• pp.104-120
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• 2004

Animation character market in Korea has been dominated by licensed characters (e.g., Walt Disney′s) of which market share is 80%. While market share for Korean characters such as "Mashimaro" and "Little Dinosaur Dooly" is increasing, the application of such characters to fashion products is still limited. For the development of the Korean character market, application of original animation characters should be applied to various fashion products. The main purpose of this study was to design toddler apparel line using "Little Dinosaur Dooly," one of the most popular domestic animation characters. The design focus is the green color of Dooly because the color is the distinctive concept of the brand. Results of the study indicated that developing toddler apparel line with a Korean animation character was a meaningful attempt, as imported licensed characters were dominant in domestic fashion market. The key differentiating factor was the use of green color. In addition, use of various supporting characters, namely Dooly′s friends, demonstrated potential line extension forming animation character groups similar to Warner Brothers′"Looney Tunes."

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.25-28
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• 2005

For Korean game development technology, recently acknowledged as world-class, being aware of the importance of characters in the games, this paper will intend to contribute to the improvement of game character development quality by analysis of Korean on-line game transition focusing on the expressive quality of characters.