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실시간 비디오 스트리밍 서비스를 위한 선별적 비디오 암호화 방법의 전송지연 저감 연구
윤요한,고경민 한국정보통신학회 2021 한국정보통신학회논문지 Vol.25 No.4
Real-time video streaming scheme for multimedia content delivery and remote conference services is one of technologies that are significantly sensitive to data transmission delay. Recently, because of COVID-19, real-time video streaming contents for the services are significantly increased such as personal broadcasting and remote school class. In order to support the services, there is a growing emphasis on low transmission delay and secure content delivery, respectively. Therefore, our research proposed a packet aggregation algorithm to reduce the transmission delay of selectively encrypted video transmission for real-time video streaming services. Through the application of the proposed algorithm, the selectively encrypted video framework can control the amount of MPEG-2 TS packets for low latency transmission with a consideration of packet priorities. Evaluation results on testbed show that the application of the proposed algorithm to the video framework can reduce approximately 11% of the transmission delay for high and low resolution video. 실시간 비디오 스트리밍은 컨텐츠 전달 및 원격회의 등에 사용되는 기술로, 전송지연에 민감한 기술 중 하나이다. 최근 코로나바이러스 감염증(COVID-19)으로 인해 개인방송/원격회의와 같은 개인이 제작 및 이용하는 컨텐츠들이 증가하면서, 실시간 비디오 스트리밍 시 전송지연 저감과 더불어 스트리밍 되는 컨텐츠에 대한 보호의 필요성이 강조되고 있다. 따라서, 본 연구에서는 실시간 비디오 스트리밍에 선별적 비디오 암호화 방법을 적용할 경우 발생하는 전송지연을 저감하기 위한 패킷 응집 관련 알고리즘을 제안하였다. 제안 방법은 선별적 비디오 암호화 프레임워크에서 패킷 단위로 재배치된 비디오 데이터 전송 시 한 번에 전송되는 크기의 조절이 가능하도록 개선하였으며, 실제 테스트베드를 통한 실험결과는 제안 방법 적용 시 기존대비 전송지연을 약 11% 저감할 수 있음을 보여주었다.
윤요나,이용삼,chunhweykim,김영기,임홍서,한원용,정장해 한국우주과학회 2012 Journal of Astronomy and Space Sciences Vol.29 No.4
Astronomical Observations at Chungbuk National University Observatory (CBNUO) with an 1 m telescope have begun since April 2008, and Near-Earth Space Survey observations also have been started since November 2010, with a 0.6 m wide field telescope developed by Korea Astronomy and Space Science Institute. To improve observational efficiency, we developed a weather monitoring system enabling automatic monitoring for the weather conditions and checking the status of the observational circumstances, such as dome status. We hope this weather monitoring system can be helpful to more than 100 Korean domestic observatories, including public outreach facilities. In this paper, we present the statistic analysis of the weather conditions collected at CBNUO for 3 years (2009- 2011) and comparisons were made for clear nights between using only humidity data and both humidity and cloud data.
태양전파 교란 실시간 모니터링 시스템 구축 I. 전파망원경 구동시스템
윤요나,김용기,이충욱,차상목 한국우주과학회 2004 Journal of Astronomy and Space Sciences Vol.21 No.2
As the first step of the real time monitoring system of the solar radio disturbance, we constructed the control system of the solar radio telescope. An 1.8m antenna built by Korean Astronomy Observatory has been used, and the observed radio flux is transformed to the digital signal by the powermeter. We have also developed a computer program CBNUART in order to control the telescope system and the powermeter. As the sun rises, the telescope begins to observe the sun, and ends the observation automatically at sunset. The CBNUART enables the telescope automatically to go to the position of the sunrise for the beginning the observation and come back to the setposition after the ending the observation at the sunset. An active tracking routine is adopted in order to improve the tracking accuracy of the control system, and we used an optical telescope equipped in front of the antenna for control test. The tracking test shows that our control system can track with the accuracy of arc seconds, and the 50 minute pointing test shows that the pointing accuracy of right ascension and declination are 1.12 and 0.08 arc minutes respectively.
윤요한 한국축산식품학회 2010 한국축산식품학회지 Vol.30 No.6
This study evaluated the antimicrobial effects of meat processing-related organic acids on Burkholderia thailandensis (Burkholderia pseudomallei surrogate) with different water activities. B. thailandensis KACC12027 (4 log CFU/mL) was inoculated in microwell plates containing tryptic soy broth pH-adjusted to 4, 5, 6, and 7 with ascorbic acid, citric acid, and lactic acid and with water activities adjusted to 0.94, 0.96, 0.98, and 1.0 with NaCl, followed by incubation at 35℃ for 30h. The optical density (OD) of the samples was measured at 0, 3, 6, 12, 24, and 30 h at 595 nm to estimate the growth of B. thailandensis. Growth of B. thailandensis was observed only at water activity of 1.0. In general, more bacterial growth (p<0.05) was observed at pH 6 than at pH 7, and the antimicrobial effects of the organic acids on B. thailandensis were in the following order: Ascorbic acid > lactic acid > citric acid after incubation at 35℃ for 30 h. These results indicate that organic acids in meat processing-related formulations should be useful in decreasing the risk related to an emerging high risk agent (B. pseudomallei).