• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.4
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• pp.43-54
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• 2004

A visualization study was carried out to investigate the effects of phase difference qualitatively by examining wake pattern on the phase difference of a dragonfly type wing model. The model was built with scaled-up, flapping wings composed of a paired wing with fore- and hind-wings in tandem that mimick the wing form of a dragonfly. The present study was conducted by using the smoke-wire technique and an electronic device below the tandem wings was mounted to find the exact wing position angles. Uncertainties in wing position angle are about $\pm$$1.0^{\cire}$ and instantaneous wing positional angle varies from $-16.5^{\cire}$ to $+22.8^{\cire}$. The tests were made at phase differences between the fore-wing and hind-wing at $0^{\cire}$, $90^{\cire}$, $180^{\cire}$ and $270^{\cire}$. The results show that Karman vortex structures were produced at phase differences of $90^{\cire}$, $180^{\cire}$ and $270^{\cire}$, but Karman vortex structures were not observed at the phase difference of $0^{\cire}$.

• Journal of the Korea Society of Computer and Information
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• v.15 no.8
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• pp.163-171
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• 2010

This research has studied developing the persona model based on alan cooper's user oriented design which is newly in the limelight in the field of product design process. As developing the persona model, In-depth interview and FGI(focus group interview) has been conducted for extracting car navigation user group's motivation and using attribute. Based on research, three different car navigation user group were divided-low using & understanding the function group, medium using & well understanding the function group, heavy using & well understanding the function group. This research yielded the foundation for setting the persona model and this persona gives the key factor for producing the user oriented user Interface design after all.

• Journal of the Korean Society for Computer Game
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• v.31 no.4
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• pp.1-8
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• 2018

The present study investigated the validity of a serious game named 'Draw Ttoring' developed for accessment of children's attention and tried to provide the basic information about it. To this goal, we tested it to 284 elementary school students in measuring various behavior data(reaction time, total playing time, correct rate, discrepancy between type of TMT). Futhermore, the behavior data was compared with academic achievement to see the external validity. In results, 'Draw Ttoring' showed various behavior data and correlation with academic achievement. In Type A of TMT, total time and reaction time had a correlation with academic achievement, while, in Type B of TMT, total time and correct rate did. Mental flexibility calculated by the discrepancy between Type A and Type B showed also the positive correlation with academic achievement. These results showed that the serious game named 'Draw Ttoring' can provide more various information about children attention and these can't be observed by traditional paper pencil test. Finally, serious game can provide an good alternative method to access children's cognition.

• Progress in Medical Physics
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• v.15 no.4
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• pp.228-236
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• 2004

Retinal ganglion cells transmit visual scene as an action potential to visual cortex through optic nerve. Conventional recording method using single intra- or extra-cellular electrode enables us to understand the response of specific neuron on specific time. Therefore, it is not possible to determine how the nerve impulses in the population of retinal ganglion cells collectively encode the visual stimulus with conventional recording. This requires recording the simultaneous electrical signals of many neurons. Recent advances in multi-electrode recording have brought us closer to understanding how visual information is encoded by population of retinal ganglion cells. We examined how ganglion cells act together to encode a visual scene with multi-electrode array (MEA). With light stimulation (on duration: 2 sec, off duration: 5 sec) generated on a color monitor driven by custom-made software, we isolated three functional types of ganglion cell activities; ON (35.0$\pm$4.4%), OFF (31.4$\pm$1.9%), and ON/OFF cells (34.6$\pm$5.3%) (Total number of retinal pieces = 8). We observed that nearby neurons often fire action potential near synchrony (< 1 ms). And this narrow correlation is seen among cells within a cluster which is made of 6～8 cells. As there are many more synchronized firing patterns than ganglion cells, such a distributed code might allow the retina to compress a large number of distinct visual messages into a small number of ganglion cells.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.404-414
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• 2020

This study aims to explore latent classes in terms of changing patterns in achievement motivation among the samples from elementary school to middle school students in multicultural families and to investigate factors to predict latent groups and their relationship with academic achievement. 1254 pairs of mother and child from the 1st to 6th years of Multicultural Adolescents Panel Study (MAPS) was utilized for the Latent Class Growth Analysis (LCGA), One-way ANOVA, Multinomial Logistic Regression. The results showed that there were four distinct subgroups within the samples in terms of achievement goal orientations (i.e. very-high changing group, average changing group, low stable group, very-low stable group) at all six time points, and students who reported high achievement motivation were likely to have higher academic achievement. Four groups were extracted based on parent's efficacy, students' self-esteem, and teacher's support. Suggestions and practical implications for understanding the types of subgroups for the achievement motivation of multicultural families were discussed.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.41-42
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• 2016

본 논문에서는 급증하는 사회적 문제인 자살에 대해 가상현실 체험을 통해 예방할 수 있는 콘텐츠 설계를 제안한다. 엔터테인먼트 형태의 콘텐츠로 뇌파 측정을 하여 자살증후군을 가진 대상자를 선별하고 이에 따른 자살동기 유형별 적합한 자살예방콘텐츠를 설계하는 것이다. 콘텐츠 설계는 자살예방을 위한 검증된 프로그램을 적용하고 사용자의 자연스러운 몰입을 유도하도록 VR 기기를 활용한다. 콘텐츠 사용을 통하여 수집된 데이터 분석으로 오프라인 전문가의 심층적인 치료 및 교육이 가능하도록 연계한다. 본 논문에서 설계된 콘텐츠를 이용하여 자살에 대한 경각심을 주거나 예방을 할 수 있을 것으로 기대한다.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2002.05a
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• pp.9-14
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• 2002

인터넷에 기반한 학습 콘텐츠가 보편화됨에 따라 이에 대한 사용자들의 요구도 다양화되고 있다. 이중 컴퓨터에 기반한 평가(CBT: Computer Based Test) 시스템은 학술적으로나 경제적으로 최근 그 방법론이 평가 및 개발 분야에 있어 다양하게 진행되고 있다. 그러나 현재 개발된 대부분의 CBT 시스템 환경은 관계형 데이터베이스에 기반하여 개발되었기 때문에 다양한 형태의 문제를 구현하기 어려울 뿐만 아니라, 관리 측면에서도 높은 비용을 요구한다. 본 연구는 이러한 문제점이 문항 정보는 동적인데 비해, 기존 전산 정보 환경은 정적인 것에서 비롯되었다 보고, 이에 대한 구조적 해결책을 제시하기 위해 최근 그 사용이 급증하고 있는 XML(eXtensible Markup Language)을 이용하였다. 컴퓨터 환경 관점과 문항 저작 관점 모두를 충족시키기 위해 XML의 요소(element) 정의는 컴퓨터 친화적(computer friendly) 요소와 콘텐츠 친화적(computer friendly) 요소로 분류하고, 각 요소별로 중복되지 않는 정보 유형을 추출하였다. 본 연구결과를 활용할 경우 기존 관계형 데이터베이스에 비해 동적인 정보를 손쉽게 구현할 수 있을 뿐만 아니라, 다른 XML 문서와 동기화 작업을 거칠 경우 문항 세트를 손쉽게 확장할 수 있어 경제적이고 관리가 용이하여 관련 분야 연구를 촉진할 것이다.

• Journal of the Korea Society of Computer and Information
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• v.17 no.4
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• pp.163-172
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• 2012

Modern society, various great strength crimes are producing. After all crimes happen, it is most important that prevent crime beforehand than that cope. So, many research studied to prevent various crime. However, existing method of studies are to analyze and prevent by society and psychological factors. Therefore we wishes to achieve research to forecast crime by time using Markov chain method. We embody modelling for crime occurrence estimate by crime type time using crime occurrence number of item data that is collected about 5 great strength offender strength, murder, rape, moderation, violence. And examined propriety of crime occurrence estimate modelling by time that propose in treatise that compare crime occurrence type crime occurrence estimate price and actuality occurrence value. Our proposed crime occurrence estimate techniques studied to apply maximum value by critcal value about great strength crime such as strength, murder, rape etc. actually, and heighten crime occurrence estimate probability by using way to apply mean value about remainder crime in this paper. So, we wish to more study about wide crime case and as the crime occurrence estimate rate and actuality value by time are different in crime type hereafter applied examples investigating.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.1
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• pp.1-6
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• 2022

Recently, IoT sensors are often used to produce stream data locally and they are provided for edge computing applications. Mass-produced data are stored in the mobile device's database for real-time processing and then synchronized with the server when needed. Many mobile databases are developed to support those applications. They are CloudScape, DB2 Everyplace, ASA, PointBase Mobile, etc, and the most widely used database is SQLite3 on Linux. In this paper, we focused on the performance required for synchronization with the server. The search performance required to retrieve SQLite3 was compared and analyzed according to the type of each Linux file system in which the database is stored. Thus, performance differences were checked for each file system according to various search query types, and criteria for applying the more appropriate Linux file system according to the index use environment and table scan environment were prepared and presented.

• (The) Research of the performance art and culture
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• no.39
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• pp.701-748
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• 2019

Gwanak-yeongsanhoesang, called as Samhyeon-yeongsanhoesang or Pyojeongmanbangjigok, is played by the musical instrumental organization, Samhyeonyukgak or by a large scale wind ensemble added Sogeum and Ajaeng. This study aims to analyze the structure and form of Piri melody which plays major melody of Sangnyeongsan in Gwanak-yeongsanhoesang, and to examine the relationship between Piri melody and Daegeum yeoneum grasping the structure and function of yeoneum. In Sangnyeongsan of Gwanak-yeongsanhoesang, the criterion for grouping the phrases of Piri melody is yeoneum. Especially, Daegeum yeoneum carries out the function of finishing the phrase of Piri playing the major melody by ornamenting or extending it, and presenting the motives or motive elements of the next phrase while Piri rests. The types of a, b, g, and i in the various shapes of the minimum melodic fragment of Piri are important motive elements that constitute a phrase of Piri melody. Especially, main motive a-type (仲→無) contrasts with b type (林→潢) which forms a strong tension by transposing 2 degrees upward. In addition, a-type gradually descends towards the end of music by changing to g-type (仲→林) or to i-type (太→林) which is 3 degrees below, which is related to the gradual descent cadence of Korean traditional music. A phrase of Piri melody of Sangnyeongsan in Gwanak-yeongsanhoesang consists of a combination of the types a, b, g, i, and cadence (x-type), and each phrase is structured in the repeating tension-relaxation. Looking at the structure of Piri phrases by similar types, each phrase has a logical variation structure through the methods such as omission and addition of notes, and crossing of melodies. The shape of the minimum melodic fragment of Daegeum yeoneum can be divided into a back-yeoneum of a~b types and a front-yeoneum of x1~x3. The x-types ornament Jungnyeo (仲), the cadence tone of Piri melody or are simply used as the extending back-yeoneum, and types a and b have the function of a front-yeoneum that prepares the beginning of the next phrase of Piri melody. The combination types of the minimum melodic fragment of Daegeum yeoneum appear mostly as the shape of back-yeoneum + front-yeoneum. In addition, the front-yeoneum of the type a and b appears independently without back-yeoneum, and the x3 type has a shape of the back-yeoneum without the front-yeoneum. Looking at the structure of Daegeum yeoneum by similar types, it can be seen that Daegeum yeoneum is also composed of a variation structure of omission and addition of notes like Piri melody.