• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.2
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• pp.73-79
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• 2001

Experiment were carried out to investigate the heat transfer characteristics of an aluminum foam block as a porous heat sink on a heat source by a vertical air jet impingement that can be applied for electronics cooling. The performance of the aluminum foam heat sink was evaluated by the convective heat transfer coefficient on the heat source. At a fixed porosity, pore density ($\beta$) of the foam and Reynolds number Re were varied in the range of $\beta$a=10, 20, 40 PPI(Pore Per Inch) and $850\leqRe\leq25000$. A nozzle diameter and the nozzle-to-plate spacing were also varied. It was found that the convective heat transfer was enhanced by the aluminum foam heat sink with lower pore density due to relatively intensified flow through the foam block. The aluminum foam block with much reduced weight shows slightly better performance with larger Nusselt number, compared with the convectional heat sink.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.8
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• pp.667-673
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• 2003

Recent trends in the electronic equipment indicate that the power consumption and heat generation in a chip increase as the components are miniaturized and the computing speed becomes faster. Suitable heat dissipation is required to ensure the guaranteed performance and reliable operation of the electronic devices. The aim of the present study is to investigate the forced-convective thermal-hydraulic characteristics of a pin-fin heat exchanger as a candidate for cooling system of the electronic devices. The influence of the structure of the pin-fin assembly on heat transfer is investigated by porous medium model. The results are compared with the experimental data or correlations of several researchers for the heat transfer coefficients for the channel flow with pin-fin arrays. Finally, the effects of design parameters such as the pin-fin diameter and the spacing are examined.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.156-157
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• 2018

본 논문에서 제안하는 기술은 무인기 획득 영상에 dense optical flow 기술을 적용하여, 이미지 내에서 급격히 움직이는 사물을 추출하는 기술이다. 제안 기술을 활용하여 사람, 사물 장소에 해당하는 시간에 따른 데이터인 다중로그 데이터로 융합 분석하여 낙석, 산사태, 비탈면 붕괴등을 감지 할 수 있게 되어 보행자의 안전을 보장 하고자 한다. 본 논문에서는 해당 기술을 구현하기 위한 무인기 및 탑재 장비와 데이터 처리를 위한 서버들간의 인터페이스 및 분석 알고리즘을 소개한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.173-174
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• 2018

배경제거는 영상에서 움직이는 객체를 분리할 때 유용한 방법이며, 대표적인 예인 Mixture of Gaussian (MOG) 알고리즘은 픽셀 당 3-5 가우스 모델을 혼합해 배경과 움직이는 객체를 구분한다. 소형 표적을 추적하기 위해서는 화소 혹은 작은 블록 단위로 시/공간적 밝기 변화량을 이용하는 옵티컬 플로우 기법이 적절하다. 본 논문에서는 소형 표적의 강인한 객체 추적을 위해 MOG2와 옵티컬 플로우의 결합 방법을 소개한다. 제안된 방법은 MOG2를 사용하여 전경 영역을 획득하고 전경 영역에만 옵티컬 플로우를 적용한다. 실험 결과는 제안 방법이 잡음과 배경의 미세 변화가 있더라도 무인 비행체를 잘 추적할 수 있음을 보여준다.

• Asia Marketing Journal
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• v.22 no.4
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• pp.151-170
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• 2021

This case study research analyzes the cross-artistic project Connect, BTS and its relationship to transmedia branding, meaning-making and spatiality. After an overview of the argument and a section on methodology, the reader will find the analysis of the case study. Thanks to the use of a qualitative approach, this examination of Connect, BTS unveils the ways in which this initiative becomes a location that allows a reconceptualization of space that fosters plurality, exchange, and subjectivity. Connect, BTS unites seemingly incompatible fields under one project, favoring the co-creation of meanings among different artists, BTS, ARMY (the group's fans), business partners and viewers. This process has been investigated through content analysis, exploring Connect, BTS's transmedia strategies from branding to storytelling, to evaluate their efficacy in regard to brand identity, brand experience, and brand trust. The paper will also explore the variety of layers and spatial dimensions contained in Connect, BTS, which flow from art to the music industry, material and digital space, various market sectors and media. In light of this, Connect, BTS embraces a galaxy of separate semantic units into an extended liminal continuum that does not discount difference.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.927-931
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• 2021

In this work, an attempt is made to improve the electrochemical corrosion resistance of Zircaloy-4 by helium ions implantation. For this purpose, the Zircaloy-4 was implanted with 300 keV helium ions of fluences 1 × 10¹³, 1 × 10¹⁵, and 1 × 10¹⁶ ions-cm^-2 by using Pelletron Accelerator. Electrochemical tests of pristine and ion-implanted samples were performed in NaCl solution and their potentiodynamic polarization curves were obtained. The results showed enhancement of the corrosion resistance of Zircaloy-4 after helium ions implantation. The corrosion rate and current density of the material were significantly reduced by the helium implantation. The decrease in corrosion parameters was attributed to helium ions diffusion inside Zircaloy-4 that reduced the electrons flow from the samples.

• Journal of information and communication convergence engineering
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• v.20 no.4
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• pp.273-279
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• 2022

Owing to the need to establish a cooperative-intelligent transport system (C-ITS) environment in the transportation sector locally and abroad, various research and development efforts such as high-tech road infrastructure, connection technology between road components, and traffic information systems are currently underway. However, the current central control center-oriented information collection and provision service structure and the insufficient road infrastructure limit the realization of the C-ITS, which requires a diversity of traffic information, real-time data, advanced traffic safety management, and transportation convenience services. In this study, a network construction method based on the existing received signal strength indicator (RSSI) selected as a comparison target, and the experimental target and the proposed intelligent edge network compared and analyzed. The result of the analysis showed that the data transmission rate in the intelligent edge network was 97.48%, the data transmission time was 215 ms, and the recovery time of network failure was 49,983 ms.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.322-324
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• 2021

최근 고주사율 디스플레이 시장 확대와 실감콘텐츠에 대한 요구에 따라, 높은 프레임율의 동영상 콘텐츠에 대한 관심이 증가하고 있다. 본 논문은 이용자의 비디오를 초슬로우 비디오로 변환해주는 웹 기반 서비스 시스템을 제안한다. 이는 사용자가 웹을 통해 비디오를 업로드하면, 딥러닝 기반의 비디오 프레임 보간 알고리즘을 이용하여 초고프레임율의 동영상으로 변환하며. 변환된 초저속 비디오를 웹을 통해 보여주거나 파일 포맷으로 제공한다. 제안 시스템은 복잡한 연산을 요구하는 딥러닝 네트워크 모듈과 사용자와의 상호작용을 위한 웹 페이지 모듈로 구성되었다. 프레임 보간을 위해서, State-of-the-art 기술인 딥러닝 기반의 Real-Time Intermediate Flow Estimation for Video Frame Interpolation 방법이 활용되었으며, 웹페이지는 HTML, CSS, Javascript, Flask를 사용하여 구축되었고, Flask를 활용하여 두 모듈이 연동되었다. 제안 웹 기반 시스템을 통해, 사용자는 딥러닝 네트워크 구동에 필요한 별도의 지식 없이 통신 자원만으로 고실감의 경험과 편의성을 제공받을 수 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.214-216
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• 2022

비디오 프레임 보간 기술은 시간 해상도를 증가시키는 기술로 최근 Convolutional Neural Network(이하 CNN) 기반의 다양한 연구가 진행되고 있다. 하지만 일부 시각에서는 CNN 기반의 연구가 동일한 커널을 모든 화소에 적용하는 것과 객체의 움직임을 예측하기 위해 장기간의 데이터를 활용하는 것에 한계점이 있다고 주장한다. 이에 따라 장기간의 데이터 활용에 특화된 트랜스포머 기반의 비디오 프레임 보간 기술이 제안되었다. 본 논문에서는 트랜스포머 기반의 기존 연구에서 합성 네트워크의 성능을 향상시키기 위해 광학 흐름 안내 기반의 새로운 학습 방법을 제안한다 실험 결과를 통해 평균 PSNR 0.09dB와 SSIM 0.0031 성능 향상을 확인한다.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.261-265
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• 2014

As the need for miniaturization in water purification filter increases, the development of filter media for single filtration with multiple function was strongly required. In this study, the molded activated carbon composed of single unit was manufactured by extrusion-sintering process, and then the flow rate, density and porosity were investigated using the molded activated carbon manufactured at various extrusion temperature. We confirmed that it was possible to manufacture the single unit-molded activated carbon when the extrusion temperature was $140{\sim}230^{\circ}C$ more than $133^{\circ}C$ being of polymer binder melting point, and the optimal extrusion temperature for the molded activated carbon with maximum flow rate was $170^{\circ}C$ since the molded activated carbon had low density and high through porosity. Also we confirmed that the flow rate through the molded activated carbon was strongly dependent upon through pore porosity compared to total porosity for the molded activated carbon.