• Title/Summary/Keyword: 탈의

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Management of Test Facility for Tests of Liquid Rocket Engine on Off-Design Condition (액체로켓엔진 탈설계 조건 시험을 위한 시험설비 운용)

  • Yu, Byungil;Kim, Hongjip;Han, Yeongmin
    • Journal of Aerospace System Engineering
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    • v.14 no.5
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    • pp.91-99
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    • 2020
  • A liquid rocket engine goes through many tests to prove its performance before liftoff. It means the tests for setting ignition and start-up conditions or a test on design condition, which verifies the design performance. However, the development process requires verification of performance under off-design conditions through tests involving different operating conditions, which affects the duration of engine development. The off-design performance test is performed by altering the conditions of the propellant supplied to the engine in conjunction with the engine performance test that varies the opening of the control valves in the engine. This paper is based on the results of the engine tests performed at the KSLV-II engine test facilities in the Naro Space Center and describes the operations of the test facility for off-design condition test that changes the inlet conditions of the turbo-pump due to changes in the pressure and temperature of the propellant supplied to the test engines.

Design and Implementation of the Evaluation Framework for Decentralized Multimedia Streaming Services

  • Park, Sangsoo
    • Journal of the Korea Society of Computer and Information
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    • v.25 no.9
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    • pp.91-100
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    • 2020
  • This paper presents an evaluation framework for prototyping multimedia streaming services including audio and video in a distributed and/or decentralized storage that can evaluate service quality and performance under various network conditions. The evaluation framework focuses on important indicators which measure and improve service quality by applying decentralized storage to multimedia streaming services that can mimic the scalability of the existing server-client software architecture and the issue of a single point of failure. The integrated framework not only measures performance indicators for evaluating the quality and performance of multimedia streaming on open source based multimedia content streaming services, but also adjusts network quality using network virtualization technology for comprehensive evaluations. The experimental results show that the integrated framework has low overhead in building and operating a decentralized storage with multimedia streaming services on a single host computer which validates the scalability of the developed framework.