• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권8호
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• pp.2814-2832
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• 2014

As information society matures to an even higher level and as information technology becomes a necessity to our everyday lives, the needs to develop, support and satisfy personal and social needs without the limitation of time, space, and location have become a vital point to everyday lives. Smartphone users are increasing at a staggering rate but the research on mobile-Learning model and the implementation of m-Learning scenario are still behind the needs of the users. Therefore, this paper focuses on the design of 'repeatable and short-spanned m-Learning model' to meet the needs of the learners who are on the go and on the move with their smartphones. Smartphone users frequently reach out for their phones but compare to the frequencies, the actual span of time they spend per use are relatively and surprisingly short. One way to understand this phenomenon is that the users tend to immediately replace their smartphones with laptops or desktops whenever they are available. A leaning model was needed to reflect this short and frequent use, a use that is solely based on the smartphone environment. This proposed learning model first defines this particular setting and implements the model to real smartphone users over an 8 week period. To understand whether different learning backgrounds can influence this model, different schools with online and offline learning channels participated in the experiment. User survey was conducted after the experiment to get a better understanding of the smartphone users. Pretest and posttest were conducted before and after the experiment and the data were validated and analyzed using SPSS version 18.0 for PC. Preliminary descriptive statistics, multiple regression and cross validation was conducted for the analysis. The results showed that the proposed English Listening and Comprehension Mobile Digital Textbook (ELCMDT) had a positive effect on the learners in general and was more effective for learners who were already experienced with online learning.

• 방송공학회논문지
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• 제22권5호
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• pp.589-599
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• 2017

본 논문은 후각실험에 사용되는 향기에 대한 신뢰성을 검증하기 위한 연구로 MPEG-V(ISO/IEC 23005) 표준을 활용한 후각효과 재현 시스템을 소개한다. 구현된 시스템을 활용하여 실험 참여자들에게 두부장착교시장치(Head Mounted Display: HMD)를 착용시킨 상태에서 향기와 향기객체 이미지의 일대일 매칭, 향기와 다수의 향기객체 이미지 매칭, 그리고 발향장치와 피험자와의 거리별 선호도 분석을 실시하였다. 실험 결과 분석을 통해 후각도구로 커피, 코코아, 바나나, 복숭아 향기를 실험에 적합한 향기로 선정하였다. 매칭 정확도가 높았던 커피 향기의 경우 발향장치와 참여자 사이의 거리가 10~20cm인 경우가 30cm보다 이미지 매칭에 더 효과적이었다. 향후 본 연구를 통해서 선정된 향기를 사용하여, 가상현실 콘텐츠의 몰입감 및 현장감 향상을 위한 후각 연구를 진행할 것이다.

• 대한기계학회논문집B
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• 제28권3호
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• pp.265-270
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• 2004

Experiment study on a down scaled two-phase catalytic reactor is presented. As a preliminary step for the development of catalytic reactor, nano-particulate catalyst was prepared. Perovskite La$\_$0.8/Sr$\_$0.2/CoO$_3$is chosen and synthesized as a catalyst considering superior catalytic performance in reduction and oxidation process where oxygen is involved among the reagent. Reactor that has a scale of 2${\times}$10${\times}$25mm was made by machining of A1 block as a layered structure considering further extension to micro-machining. Hydrogen peroxide of 70wt% was adopted as reactant and was provided to the reactor loaded with 1.5 g of catalyst. Reactant flow rate was varied by precision pump with a range of 0.15cc/min to 17.2cc/min. Temperature distribution within reactor was recorded by 3 thermocouples and total amount of liquid product was measured. Temperature distribution and factors that affect temperature were observed and relation between temperature distribution and production rate was also analyzed. Relative time scale plays a significant role in the performance of the reactor. To obtain steady state operation, appropriate ratio of flow rate, catalyst mass and reactor geometry is required and furthermore to get more efficient production rate temperature distribution should be evenly distributed. The database obtained by the experiment will be used as a design parameter for micro reactor.

• 해양환경안전학회지
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• 제18권3호
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• pp.221-226
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• 2012

본 연구는 미리 지정된 항로를 따라 항해하기 위한 선박의 Track-keeping에 대한 기초 실험 연구 분석결과를 제시하였다. 항로상에 위치한 여러 가지 변침점을 설정하고, 해당 선박이 그 항로를 항해하도록 알고리즘을 구성, 모형선을 이용한 실험 결과를 보여주었다. 지정된 구역에서 GPS로 변침점을 설정하고, 그 포인트를 Data화하여, 미리 프로그램된 알고리즘에 입력하면 해당 선박이 자동으로 항로를 항해하도록 설계되었다. PD 제어를 이용하여 침로 유지 알고리즘을 구성하였고, 선박 자동 Track-keeping 결과는 모니터링 가능토록 하였고, 변수를 설정 변경하도록 설계되었다. 제시된 알고리즘은 실험을 통하여 그 알고리즘의 효용성을 확인할 수 있었으며, 실선의 항해 자동화 및 충돌회피, 자동접안 등의 다양한 분야에 응용될 수 있을 것으로 판단된다.

• 한국초등과학교육학회지:초등과학교육
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• 제34권2호
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• pp.210-223
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• 2015

The purpose of this study was to analyze the stresses of teachers for elementary science class. To do these, the Science Teacher Stress Inventory has been developed the Science Teacher Stress Inventory, which consisted of 45 stress factors with subcategories such as student characteristics, teacher characteristics, expertise of science education, school environment, and administrative procedures. 120 teachers for elementary science class have participated in this questionnaire survey. The results of this study are as follow: First, stress from teacher characteristics is perceived as having more stress factors than five stress factors (student characteristics, teacher characteristics, expertise of science education, school environment, and administrative procedures). but all of the five stress factors was under normal. The detail question of stress such as 'Having to guide educational guidance and course in life education', 'Having to cope with the demand of new curricula', 'Pace of the school day is too fast', 'No time to attend training of the experiment (preliminary experiment)', 'Not enough time to complete lesson preparation and marking', 'Having to cope with non-teaching delegated duties', 'Fear of getting injured as a result of lab accidents' are perceived as having a lot of stresses. Second, there were not statistically significant differences in their personal variables such as gender, the course of high school. but there were statistically significant differences in their personal variables such as whether elementary subject exclusive science teacher, career in education experience, teaching grade. Third, coping ways of stresses are active support for better science teaching conditions, training of the experiment for expertise of science education, developing a workbook for science class.

• Asian Journal of Atmospheric Environment
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• 제8권4호
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• pp.175-183
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• 2014

To visually and chemically verify the rainout of soot particles, a model experiment was carried out with the cylindrical chamber (0.2 m (D) and 4 m (H)) installing a cloud drop generator, a hydrotherometer, a particle counter, a drop collector, a diffusing drier, and an artificial soot particle distributer. The processes of the model experiment were as follows; generating artificial cloud droplets (major drop size : $12-14{\mu}m$) until supersaturation reach at 0.52%-nebulizing of soot particles (JIS Z 8901) with an average size of $0.5{\mu}m$-counting cloud condensation nuclei (CCN) particles and droplets by OPC and the fixation method (Ma et al., 2011; Carter and Hasegawa, 1975), respectively - collecting of individual cloud drops - observation of individual cloud drops by SEM - chemical identifying of residual particle in each individual droplet by SEM-EDX. After 10 minutes of the completion of soot particle inject, the number concentrations of PM of all sizes (> $0.3{\mu}m$) dramatically decreased. The time required to return to the initial conditions, i.e., the time needed to CCN activation for the fed soot particles was about 40 minutes for the PM sized from $0.3-2.0{\mu}m$. The EDX spectra of residual particles left at the center of individual droplet after evaporation suggest that the soot particles seeded into our experimental chamber obviously acted as CCN. The coexistence of soot and mineral particle in single droplet was probably due to the coalescence of droplets (i.e., two droplets embodying different particles (in here, soot and background mineral particles) were coalesced) or the particle capture by a droplet in our CCN chamber.

• 보존과학연구
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• 통권30호
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• pp.203-215
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• 2009

In the conservation treatment of wood remains, polymers, treatment methods, and treatment period can be varied, depending on the percentage of moisture content and species of trees. Thus, in order to apply the appropriate conservation treatment, a lot of information from the wood remains are required. Despite the information from the wood remains, testing a part of the wood remains is necessary to get information about the polymers. When the wooden coffin made of camphor trees was excavated, it was cracked in the section of radiation, and there were hairlines cracks. Therefore, without any conservation treatment, it is impossible to restore it. This experiment is for the conservation treatment of the wooden coffin excavated from Songhyun-dong tombs No 7, Changnyeong. For this experiment, I used camphor trees from Jejudo. The purpose of this experiment is to asses the possibility of preliminary testing materials before the conservation treatment on the wooden coffin. After the camphor trees from Jejudo are artificially aged by Fenton's reagent, they are As a result of oxidation by Fenton, the degree of oxidation is high in proportion to the amount of peroxide and iron sulfate. Among several samples, the sample 'na' made the most similar result to the wooden coffin from Songhyun-dong. If I use this condition to make the sample in polymer tests, it is very helpful to find the most suitable polymer for the conservation treatment of wooden coffin. After the same species of trees are oxidized by Fenton and they become the similar condition, we are able to find suitable methods of conservation treatment. The suitable methods reduce the demage of the remains and make us to get more information. Thus, we are able to carry out conservation treatment more exactly.

• 한국구조물진단유지관리공학회 논문집
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• 제22권1호
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• pp.115-122
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• 2018

"일라이트와 이산화티탄을 활용한 콘크리트 블록의 수질환경개선을 위한 실험연구"를 진행하기 위해 모르타르 예비실험, 수질정화특성, 방오실험, 어독성 실험 및 실 콘크리트 블록 제조 후 관련 KS에 준한 실험을 진행한 결과 다음과 같은 결론을 얻었다. KS에 준한 콘크리트 블록의 성능평가 결과 전 조건에서 시험기준치의 압축강도를 상회하는 것으로 측정되었으며, 다공질구조의 일라이트 치환에 따른 흡수율 증가가 문제점으로 예상되었으나, 이산화티탄과 사전 혼합하여 치환함으로써 일라이트의 대형 공극내 이산화티탄이 정착함에 따라 흡수율 또한 문제가 없는 것으로 관찰되었다.

• 한국수산과학회지
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• 제34권6호
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• pp.661-665
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• 2001

해상가두리의 안정성 및 기능성 향상을 위한 최적 계류시스템을 개발하기 위하여 천해역에 적합한 계류시스템을 검토하여 유연부 이 계류시스템을 선정하였다. 이를 위한 해석프로그램을 정립하고, 수리모형실험 결과와 비교하였다. 해석프로그램의 타당성을 확인 한 후, 적용할 만한 계류시스템을 구성하고 수치계산을 통하여 해상가두리를 위한 적정 계류시스템을 제시하였다. 해상가두리의 계류시스템은 유연부이 계류시스템이 권장되며, 계류배치는 탁월 외력환경과 일치하는 방향으로 하고, 수평계류삭인 나일론 로프는 해상가두리 길이의 0.5배 이상, 경사 와이어 로프는 수심의 2배 이상이 바람직한 것으로 나타났다. 또한, 중간부 이의 증설은 계류장력 및 표류변위를 감소시키는 효과를 가질 것으로 판단된다. 차후, 해상가두리의 동적응답 특성을 계류시스템 해석모델의 개발과 계류시스템의 설계가 요구된다.

• KIEAE Journal
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• 제16권4호
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• pp.63-69
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• 2016

Purpose: This preliminary study investigated a potential of the water wall systems that provide heat storage and natural lighting control simultaneously. Method: In order for transparency of the water wall to be controlled, the study first proposed two measures: to adjust transparency of the water wall; to control transparency of water wall surface. The performance of two measures then was verified and compared by experiments. In addition, a trade-off between heat collect and heat storage resulting from using additive for adjusting transparency was investigated. Result: The experiment showed that the two measures are similar in performance. The investigation of trade-off relation showed the additive should have the same heat storage as the water to prevent decrease in thermal performance of the water wall. As an economical measure to control transparency of the water wall, this study suggested a measure of secondary heat transfer systems using shading device that first absorbs solar radiation and then transfers heat to the water wall. The experiment show that performance of the proposed measure is similar to controlling transparency of water wall surface. In conclusion, it is expected that the performance of the water wall can be economically maximized by using the proposed mean in terms of heating, cooling and lighting energy saving.