• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1491-1498
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• 2003

Droplet evaporation can be used to transfer large amounts of energy since heat is transferred across a thin liquid film. Spreading the drop over a larger area can enhance this heat transfer. One method of accomplishing this is to dissolve gas into the liquid. When the drop strikes the surface, a gas bubble nucleates and can grow and merge within the liquid, resulting in an increase in the droplet diameter. In this study, time and space resolved heat transfer characteristics for a single droplet striking a heated surface were experimentally investigated. The local wall heat flux and temperature measurements were provided by a novel experimental technique in which 96 individually controlled heaters were used to map the heat transfer coefficient contour on the surface. A high-speed digital video camera was used to simultaneously record images of the drop from below. The measurements to date indicate that significantly smaller droplet evaporation times can be achieved. The splat diameter was observed to increase with time just after the initial transient dies out due to the growth of the bubble, in contrast to a monotonically decreasing splat diameter for the case of no bubbles. Bursting of the bubble corresponded to a sudden decrease in droplet heat transfer.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.474-479
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• 2006

교수학습 사이트는 교과 교육 지원이라는 특성상 그 서비스 개선에 있어서 사용자 중심적 디자인이 특히 요구된다. 기존 웹사이트 개선 연구는 단순히 웹사이트와 사용자 간의 인터랙션에서 발생하는 문제점에 초점을 맞추어 왔는데 사용자의 근본적인 니즈를 발견하고 만족시키기 위해서는 웹사이트 사용 정황의 이해라는 보다 확대된 개념에서의 접근이 필요하다. 따라서 본 연구에서는 웹사이트의 문제점 발견 및 사용자의 근본적 니즈 파악을 위하여 오프라인과 온라인 환경에 걸친 사용자 경험 관찰 프로세스를 기획하고 교수학습 사이트 서비스 개선을 위해 이를 적용하였다. 사이트 비지팅(Site Visiting), 비디오 에쓰노그라피(Video Ethnography), 사용자 다이어리 및 셀프카메라(User diary and Self camera), 그리고 인터뷰 기법이 현장 조사에서 이용되었으며 원격 사용성 평가 소프트웨어를 활용한 사용성 평가 및 카드소팅 테스트가 온라인 환경에서 진행되었다. 관찰 후 분석을 통해 교수학습 사이트의 새로운 컨텐츠 및 서비스 방향을 도출할 수 있었으며 웹사이트 사용자 경험 관찰 방법론 정립에의 가능성을 제시하였다.

• Korean Journal of Human Ecology
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• v.18 no.6
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• pp.1221-1235
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• 2009

The purpose of this study is to examine the infant-teacher interaction and its possible effects. The subjects of this study were 24 child-care teachers from Jungup City, Korea. Among them, 12 teachers participated m the program as an experimental group. The program processed 8 sessions in total, a session a week and 90 minutes for each session. The data was collected by questionnaires of infant-teacher interactions and videotapes of their linguistic and behavioral interactions between infants and teachers. The collected data was analyzed by t-tests, wilcoxon signed-rank tests, and video content analysis. As a result, the teachers in the experimental group showed more significant enhancement than teachers in the comparison group in relation to the post-test of positive linguistic interactions between infant and teacher and teacher' positive reaction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10C
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• pp.948-955
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• 2006

In this paper, we propose motion estimation and compensation using Low-Band-Shift(LBS) with Integer Lifting Shift property. To overcome shift-variant property on wavelet coefficients, the LBS was previously proposed. This method which is applied to reference frame in video coding technique has superior performance in terms of rate-distortion characteristic. However, this method needs more memory and computational complexity. For the enhancement of those disadvantages, we propose motion estimation using Low-Band-Shift with Integer Lifting. The Integer Lifting implementation gives us good efficiency of calculation and storage.

• Journal of Biomedical Engineering Research
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• v.19 no.3
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• pp.285-290
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• 1998

There are various reports on the fracture of mechanical heart valves implanted in human or animal, and they are pointed out that problems are induced by an erosion of disk surface, due to a cavitation effect. We have been investigating this mechanism using accelerated fatigue tester, and it was found that erosion was enhanced by a compliance effect in the test circuit. In this study, effects of compliance value and location on erosion were discussed, while disk closing velocity was measured by a high speed video camera. It was clarified that faster closing velocity was resulting in a enhancement of erosion on the disk surface.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.26-27
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• 2015

본 논문은 ATSC2.0 기반 8-VSB/MH 융합형 3DTV (A/104 Part 5 Service Compatible 3DTV using Main and Mobile Hybrid Delivery) 방식 수신모듈개발에 대한 내용을 기술한다. ATSC A/104 Part 5 SC-MMH 3DTV 방식은 2014. 8 월 미국의 지상파 DTV 표준화 논의단체인 ATSC 에서는 고정 HD 서비스를 위한 8-VSB 채널과, In-band 모바일 TV 서비스를 위한 ATSC M/H 채널을 이용하여, 주파수 효율을 극대화한 새로운 방식의 고정/이동 TV 융합형 3DTV 방식을 ATSC 3DTV Standard 로 채택되었으며, 2015 년말까지 좌/우영상의 화질차이 극복을 위한 화질개선안(Video Enhancement Information) 역시 ATSC 국제표준채택이 유력하다. 본 논문에서는 이와 같은 8-VSB/MH 융합형 수신기 개발에 필수적으로 필요한 8-VSB/MH 융합형 수신모듈 구현에 대한 내용을 기술한다.

• Convergence Security Journal
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• v.12 no.2
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• pp.13-21
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• 2012

The purpose of this study is to profile actual conditions of personal information protection systems operated in overseas countries and examine major considerations of personal information that security service providers must know in the capacity of privacy information processor, so that it may contribute to preventing potential occurrence of any legal disputes in advance. Particularly, this study further seeks to describe fundamental idea and principle of said Personal Information Protection Act; enhancement of various safety measures (e.g. collection/use of privacy data, processing of sensitive information/personal ID information, and encryption of privacy information); restrictions on installation/operation of video data processing devices; and penal regulations as a means of countermeasure against leakage of personal information, while proposing possible solutions to cope with these matters. Using cases among foreign countries for this study.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.9-17
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• 2019

In this article, we present a performance enhancement scheme for mobile applications by adopting persistent memory. The proposed scheme supports the deadline guarantee of real-time applications like a video player, and also provides reasonable performances for non-real-time applications. To do so, we analyze the program execution path of mobile software platforms and find two sources of unpredictable time delays that make the deadline-guarantee of real-time applications difficult. The first is the irregular activation of garbage collection in flash storage and the second is the blocking and time-slice based scheduling used in mobile platforms. We resolve these two issues by adopting high performance persistent memory as the storage of real-time applications. By maintaining real-time applications and their data in persistent memory, I/O latency can become predictable because persistent memory does not need garbage collection. Also, we present a new scheduler that exclusively allocates a processor core to a real-time application. Although processor cycles can be wasted while a real-time application performs I/O, we depict that the processor utilization is not degraded significantly due to the acceleration of I/O by adopting persistent memory. Simulation experiments show that the proposed scheme improves the deadline misses of real-time applications by 90% in comparison with the legacy I/O scheme used in mobile systems.

• Convergence Security Journal
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• v.22 no.4
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• pp.141-146
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• 2022

The iris, a biometric information, is safe, unique, and reliable, such as fingerprints, and is personal information that can significantly lower the misrecognition rate than other biometric authentication. However, due to the nature of biometric authentication, it is impossible to replace it if it is stolen. There is a case in which an actual iris photo is taken and 3d printed so that the eyes work as if they were in front of the camera. As such, there is a possibility of iris leakage through high-definition images and photos. In this paper, we propose to improve iris masking performance by supplementing iris region masking research based on existing blurring techniques. Based on the results derived in this study, it is expected that it can be used for the security of video conference programs and electronic devices.

• International conference on construction engineering and project management
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• 2017.10a
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• pp.225-234
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• 2017

Mixed-reality technologies have proven to be valuable in many architecture, engineering and construction / facilities management (AEC/FM) applications. However, its potential of being adapted to facilitate hazard identification and risk communication in construction workplaces has yet to be fully explored. This paper makes an attempt to evaluate the feasibility of applying mixed-reality to enhancing safety risk communication in construction workplaces. Experiments have been designed in which Microsoft HoloLens^® together with a developed application will be used to intervene in the practice of jobsite risk communication. A cross-sectional survey will then be followed to examine the effectiveness and acceptability of this technology through analysis on data collected from participants in the construction industry. The preliminary results show that this emerging HoloLens^® technology, compared to the traditional communication methods (i.e., phone calls, walking up people and talk, and video conferencing), facilitates accurate, prompt safety communication on construction sites. Such findings signify the potential of applying mixed-reality to safety performance enhancement in the construction industry.