• 한국정보통신학회논문지
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• 제3권2호
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• pp.447-453
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• 1999

In MHD power generation system, enthalpy of the working gas is convened to electric power directly through expansion in generator channel. It means that electric power can be generated without a moving mechanical linkage such as turbine blades. The principle of MHD generation is based on Faraday'law of induction that eletromotive force(u$\times$B) is generated when the working gas of velocity u flows a channel in which magnetic field of strength(B) exists. In this paper, helium gas seeded with cesium is used as working gas. There are two types of generator in MHD generation; linear type faraday and disk type hall generator. Rogowski coils having the bandwidth of the 100(Hz) ~ 20(kHz) were used for measuring current flowing MHD disk channel. Optimum load resistor value of the MHD generator studied was 2.5[$\Omega$]. Disk type hall generator's generation performance is the main target of this paper, which superiors to linear type Faraday generator in many points. Isentropic efficiency and enthalpy extraction rate of disk type shock tube driven hall generator is discussed here.

• 동력기계공학회지
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• 제20권6호
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• pp.34-39
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• 2016

This paper is the numerical study on the correlation of leakage by the variation of inlet pressure and clearance in hydrostatic bearing. The main goal of this study is to apply to the design of hydro system the results that the pocket pressure and the leakage rate according to the inlet pressure and the clearance between piston and cylinder tube. Because the hydrostatic bearing in hydraulic cylinder has the narrow rectangular channel between piston and cylinder tube, so to verify the numerical scheme, it has been compared with the experimental results of Brackbill and Kandlikar. The pressure data of numerical results inside narrow rectangular channel correlate was showed a good agreement with experimental results, thereby the numerical scheme was applied to the real model that is a hydraulic cylinder with the hydrostatic bearing. In conclusion, the pressure differences between inlet and pocket were shown within 3%. Leakage rates were showed rapidly increased pattern between about 4.5 and 6.7 times because the section area to calculate the leakage rates were proportioned to a square of diameter. The correlation equation was calculated among the inlet pressure, the clearance and the leakage rate by using the linear regression.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2004년도 Proceedings of 2004 Korea-Japan Joint Seminar on Particle Image Velocimetry
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• pp.125-134
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• 2004

The improvement of artificial respiration method has brought about the decrease in mortality of pulmonary diseases patients. Various respiratory curative methods, inclusive of HFOV (High Frequency Oscillatory Ventilation), have been developed for more effectual and less harmful management of acute respiratory failure. However, the mechanism of gas transfer and diffusion in a bronchiole has not yet been clarified in detail. As a first approach to the problem, we measured oscillatory flows in a Y-shaped micro-channels as bronchiole model by micro Particle Image Velocimetry(micro PIV). In order to establish the fundamental technique of PIV measurements on oscillatory air flow in a micro-channel, we used about 500-nm-diameter incense smoke particles, a diode laser, a high speed camera including an objective lens, and a HFOV, which is effective technique for medical care of pulmonary disease patients, especially, infants. The bronchiole model size is that parent tube is $500\{mu}m$ width and $500\{mu}m$ depth, and daughter tubes are $450\{mu}m$ width and $500\{mu}m$ depth. From this study made on the phenomenon of fluid in micro size bronchus branch of a lung, we succeeded to get time series velocity distribution in a micro scale bronchial mode. The experimental results of velocity distribution changing with time obtained by micro PIV can give fundamental knowledge on oscillatory airflow in micro-channel.

• International Journal of Computer Science & Network Security
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• 제22권11호
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• pp.137-140
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• 2022

The article deals with increasing the effectiveness of educational content on the YouTube channel with the help of built-in analytics tools. Particular attention is paid to the creation of quality video, taking into account the reaction of end users of video materials. Ways to increase the video audience are considered. Techniques for improving video content apply to individual videos, as well as playlists and channels in general. In this case YouTube is both an independent educational platform and an auxiliary platform in a set of various educational solutions.

• 한국콘텐츠학회논문지
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• 제21권12호
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• pp.66-75
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• 2021

우리나라에서 교통 전문 방송사는 서울시에서 운영하는 TBS와 도로교통공단에서 운영하는 TBN 두 군데이다. 본 연구는 두 군데 교통방송 유튜브 플랫폼 활용 현황과 공급되는 콘텐츠의 성격, 활용과정에서 나타난 문제점 및 개선방안을 살펴보는 것을 목적으로 한다. 먼저 유튜브 플랫폼 활용을 보면, TBS의 경우 2021년 3월 전담조직인 '스트리트31팀' 결성하여 총 10명으로 팀을 구성하였으며, TBN은 유튜브 전담조직은 따로 없이 4명의 TF팀 구성하여 운영하고 있다. TBS가 13개 유튜브 채널 중 구독자 110만 명을 보유한 '시민의 방송'을 비롯해 TBS FM(31만 명), TBS eFM(13만 명), 팩트iN스타(32만 명) 등이 주력 채널로 운영하고 있고, <골방 라이브>와 <짤짤이쇼> 등 오리지널 콘텐츠까지 제작하고 있다. 이에 비해 TBN은 메인인 'TBN 통' 구독자가 만 5천 명에 불과하고 12개 지역 네트워크의 유튜브 채널도 부산과 경인을 제외하고 천명도 안 되는 구독자를 보유하고 있다. 오리지널 콘텐츠는 <카린이/ 알려줄car>가 유일하지만 교훈적인 내용으로 별다른 주목을 받지 못하고 있다. 두 방송사 모두 직업의 안정성 때문에 구성원들의 관심 부족과 뉴미디어 콘텐츠 제작에 대해 소극적이다. 따라서 이들 두 방송사에 대한 유튜브 플랫폼 발전을 위해서는 내부의 조직변화 및 구성원들의 인식변화가 필요하고 라이브방송 활성화와 스타 크리에이터의 발굴이 요구되며, 스마트 미디어 환경에 걸맞은 콘텐츠 유통전략을 수립해야 한다.

• Nuclear Engineering and Technology
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• 제37권6호
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• pp.565-574
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• 2005

The CANFLEX Mk-V bundle is designed to improve upon the critical heat flux (CHF) characteristics of the CANFLEX Mk-IV bundle. The main difference between these two bundles is an increase in bearing pad height of about 0.3 mm in the CANFLEX Mk-IV bundle. This change in bearing pad height leads to an increase in gap flow at the bottom of the bundle, primarily eliminating the localized narrow-gap effect that limits the CHF of the CANFLEX Mk-IV bundle. The objective of this paper is to examine the effects of bearing pad height and pressure tube creep on the sheath-temperature distribution, dryout power, and dryout location, as observed ken full-scale bundle tests, between CANFLEX Mk-IV and Mk-V bundles In uncrept and crept channels. A comparison of surface-temperature differences between the top and bottom elements of the bundles showed that increasing the bearing pad height has led to a more homogeneous enthalpy distribution in subchannels of the bundle. Initial dryout locations of the CANFLEX Mk-V bundle were mainly observed at the mid-spacer plane of either the $10^{th}$ (about $80\%$) or $11^{th}$ ($20\%$) bundle in the 12-bundle string, as compared to the mid-spacer and downstream-button planes for the CANFLEX Mk-IV bundle. Dryout power and boiling-length-average (BLA) CHF values exhibit consistent trends and little scatter with varying flow conditions for both types of CANFLEX bundles in uncrept and crept channels. An increase in pressure tube creep has led to a reduction in dryout power (about $20\%$ far the $3.3\%$ crept channel and $27\%$ for the $5.1\%$ crept channel as compared to dryout powers for the uncrept channel). Increasing the bearing pad height of the CANFLEX bundle has led to an increase in the dryout power. Overall, the dryout power of the CANFLEX Mk-V bundle is 7 to $10\%$ higher than that of the CANFLEX Mk-IV bundle at the inlet temperature range of interest (i.e., between 243 and $290^{\circ}C$).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.1882-1887
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• 2007

In the present experimental study, the effect of interfacial tensions on pressure drop of air-water two-phase flow in round mini-channels was investigated. A glass (highly wettable) tube and a Teflon (poorly wettable) tube, both in 350 mm length but 1.8 mm and 1.59 mm in inner diameters each, were used for the tests. All the experiments were performed only in the plug flow regime, confirmed by visualization. In the glass tube, the gas plugs were surrounded by the liquid film along the inner periphery. On the other hand, the inner wall remained dry at the gas portion in the Teflon tube. The pressure drop of the plug flow in the Teflon tube without the liquid film) appeared much larger than in the glass tube (with the liquid film) due to dissipation of energy by movement of the wetting lines. In this paper, various correlations on the two-phase pressure drop of plug flows were compared and a modified correlation was proposed, taking account of the surface wettability.

• 한국융합학회논문지
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• 제2권3호
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• pp.45-50
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• 2011

컴퓨터를 비롯한 고집적 회로를 갖는 시스템의 작동 열 배출이나 열전소자를 이용한 냉난방시스템의 열 이동에는 고성능 열전달 통로가 필요하다. 이와 같은 고효율 열전달 시스템에 효과적으로 대처할 수 있도록 개발된 것이 나노튜브이다. 본 연구의 목적은 방열소자(이하 나노튜브라 한다.) 제조를 위한 공정과 제조시스템을 개발하는데 있다. 지금까지 국내에 보급되고 있는 나노튜브는 대부분 수입에 의존하고 있기 때문에 본 연구는 기술적인 측면에서 방열소자 개발에 기여할 뿐만 아니라 경제적으로는 큰 수입대체효과를 가져 올 것으로 기대된다. 본 연구는 나노튜브의 제조공정과 제조시스템 개발에 대한 전 과정을 보인다.

• 한국엔터테인먼트산업학회논문지
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• 제14권6호
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• pp.91-107
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• 2020

본 연구는 유튜브 커버음악 채널의 성공 요인에 대하여 정량적 연구를 하고자 하는 데 목적을 가지고 있다. 그 과정에서 기존의 정성적 연구 결과를 바탕으로 커버음악 채널의 특성을 측정하는 측정도구를 구성하고 검정하는 것이 두 번째 목적이다. 이를 위해 최근 사례연구에서 제시한 커버음악 채널의 성공 요인을 후기기술수용모형과 융합하였다. 커버음악 채널의 콘텐츠, 영상, 크리에이터, 상호작용성, 홍보라는 5가지 특성을 중심으로 척도화하여 신뢰성과 타당성 검증을 거치면서 정량화 가능성을 탐색하고 이 결과물과 후기기술수용모형에서 제시하는 중요 변인들과의 인과관계를 검증하였다. 본 연구 결과 첫째, 콘텐츠 특성은 이용자들의 정서적 즐거움에 영향을 주지 않는 것으로 밝혀졌다. 또한, 기존 사례에서 제시된 채널 특성 요인 5가지 중에서 크리에이터 특성이 정서적 즐거움에 가장 큰 영향을 미치는 요인으로 확인되었다. 둘째, 요인분석 과정에서 유튜브 커버음악 채널 특성 중 콘텐츠 특성과 영상 특성이 한 요인으로 적재되어 통합되었다. 셋째, 만족과 지속사용의도 또한 한 요인으로 통합되었다. 이러한 연구 결과를 바탕으로 커버음악 채널 운영자들은 크리에이터의 매력을 돋보이게 하는 영상콘텐츠 제작이 필요하다. 아울러 이용자들과의 상호작용과 홍보에 노력해야 한다는 것을 제시한다.

• 디지털산업정보학회논문지
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• 제20권1호
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• pp.133-147
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• 2024

In this study, we examine the components and characteristics of channel brands, the renewal process of channel brands, and the competitiveness of SBS Subusu News and MBC 14F, online channels of Korea's leading terrestrial broadcasting company. We conducted in-depth interviews with staffs YouTube news channels such as Subusu News and 14F. First, examining the brand components and characteristics of SBS's Subusu News and MBC's 14F vertical channel, Subs News maintained its direction through the renewal of the logo type, graphic characterization, emoticon production, and campaign design production. 14F focused on brand renewal of the logo type and modification of thumbnail design to reveal the identity of the channel brand. Subusu News and 14F have achieved success through a spin-off approach that considers content relevance, expanding their brand extension. As a result of analyzing the competitiveness of the channel brand, Subusu News maintained its identity as a combination of B-class sensibility and journalism, while 14F positioned itself as a channel that delivers useful information content.