• Title/Summary/Keyword: Lab scale

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Analysis of Scaling Factor applied to Lab-Scale Model for Estimating Dynamic Characteristics of Real Structures (실구조물의 동특성 파악을 위한 축소모형에 적용되는 상사비 분석)

  • Park, Gun;Yoon, Hyungchul;Kim, Sung Bo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.1
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    • pp.59-66
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    • 2021
  • The earthquakes are the natural disasters that can cause the most serious damage to civil structures. Therefore, various studies are being conducted to secure the safety of structures against earthquakes. Most studies on the safety or mechanism of civil structures during earthquakes are being conducted based on lab scale test, because real structure tests are impossible when considering the scale of civil structures. The scaling factor proposed by Iai is mainly cited, but when applying the scaling factor proposed by Iai, there are many difficulties in selecting the structural members necessary for the production of the lab scale model. This is because when applying the scaling factor proposed by Iai, the scaling factor must be applied to the elastic modulus, which is the material property of the structure. Therefore, a new method based on Iai's 's similarity law for determining scale factor is applied in this study where the material property of real structure is same as that of lab-scale model. Through the results of this study, it is considered that the characteristics of the structure calculated through the lab scale model test can more accurately reflect the characteristics of the real structure.

Optimization of Multi-time Scale Loss Function Suitable for DNN-based Audio Coder (심층신경망 기반 오디오 부호화기를 위한 Multi-time Scale 손실함수의 최적화)

  • Shin, Seung-Min;Byun, Joon;Park, Young-Cheol;Beack, Seung-kwon;Sung, Jong-mo
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2022.06a
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    • pp.1315-1317
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    • 2022
  • 최근, 심층신경망 기반 오디오 부호화기가 활발히 연구되고 있다. 심층신경망 기반 오디오 부호화기는 기존의 전통적인 오디오 부호화기보다 구조적으로 간단하지만, 네트워크의 복잡도를 증가시키지 않고 인지적 성능향상을 기대하는 것은 어렵다. 이 문제를 해결하기 위하여 인간의 청각적 특성을 활용한 심리음향모델 기반 손실함수를 사용한 기법들이 소개되었다. 심리음향 모델 기반 손실함수를 사용한 오디오 부호화기는 양자화 잡음을 잘 제어하였지만, 여전히 지각적인 향상이 필요하다. 본 논문에서는 심층신경망 기반 오디오 부호화기를 위한 Multi-time Scale 손실함수의 지역 손실함수 윈도우 크기의 최적화 제안한다. Multi-time Scale 손실함수의 지역 손실함수 계산을 위한 윈도우 크기를 조절하며, 이를 통하여 오디오 부호화에 적합한 윈도우 사이즈를 결정한다. 실험을 통해 얻은 최적의 Multi-time Scale 손실함수를 사용하여 네트워크를 훈련하였고, 주관적 평가를 통해 기존의 심리음향모델 기반 손실함수보다 좋은 음성 품질을 보여주는 것을 확인하였다.

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Study on the Combustion of the Hybrid Rocket (하이브리드 로켓의 연소현상 연구)

  • ;S. Krishnan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.10a
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    • pp.126-130
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    • 2003
  • Hybrid rocket had many advantage with compared to solid and liquid rockets. In this study, lab-scale hybrid motor was designed and manufactured. And the methods of regression rate improvement were considered. Thrust was calculated with pressure of the combustion chamber and the regression rate was measured in low flow rate of oxidizer. Several problems and solutions of operating hybrid rocket was presented.

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Vibration Response Analysis of Gravity-type Caisson Breakwater (중력식 케이슨 방파제의 진동응답 분석)

  • Lee, So-Young;Huynh, Thanh-Canh;Kim, Jeong-Tae;Han, Sang-Hun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.91-96
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    • 2013
  • In this paper, vibration response of gravity-type caisson breakwater is analyzed to suggest the direction for structural health monitoring (SHM) on harbor caisson structure. To achieve the objective, the following approaches are implemented. Firstly, vibration analysis methods are selected to examine the dynamic characteristics of the lab-scale caisson in the frequency and the modal domain. Secondly, vibration tests on the lab-scale caisson breakwater which is installed in 2-D wave tank were performed under several water level conditions. Thirdly, vibration response of the lab-scale caisson were analyzed in the frequency and modal domain. Finally, the direction of SHM for gravity-type caisson breakwater was suggested.

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A multi-modal neural network using Chebyschev polynomials

  • Ikuo Yoshihara;Tomoyuki Nakagawa;Moritoshi Yasunaga;Abe, Ken-ichi
    • 제어로봇시스템학회:학술대회논문집
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    • 1998.10a
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    • pp.250-253
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    • 1998
  • This paper presents a multi-modal neural network composed of a preprocessing module and a multi-layer neural network module in order to enhance the nonlinear characteristics of neural network. The former module is based on spectral method using Chebyschev polynomials and transforms input data into spectra. The latter module identifies the system using the spectra generated by the preprocessing module. The omnibus numerical experiments show that the method is applicable to many a nonlinear dynamic system in the real world, and that preprocessing using Chebyschev polynomials reduces the number of neurons required for the multi-layer neural network.

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Reviews on the Operation of Lab-scale Waste Landfill Simulation Reactor (실험실 규모 폐기물 모의매립조 운전에 관한 고찰)

  • Yoon, Seok-Pyo
    • Journal of the Korea Organic Resources Recycling Association
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    • v.27 no.1
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    • pp.23-32
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    • 2019
  • In this study, a comprehensive review of the results of the research on the lab-scale waste lysimeter or landfill simulation reactor, which has been conducted in Korea and abroad for the last 20 years, were investigated for the type of operation parameters, the purpose of the research, and the size of the device. From the results, the contents and limitations of lab-scale lysimeter research were discussed, and this can be used as a reference for further research.

Pretest analysis of a prestressed concrete containment 1:3.2 scale model under thermal-pressure coupling conditions

  • Qingyu Yang;Jiachuan Yan;Feng Fan
    • Nuclear Engineering and Technology
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    • v.55 no.6
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    • pp.2069-2087
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    • 2023
  • In nuclear power plant (NPP) accidents, the containment is subject to high temperatures and high internal pressures, which may further trigger serious chain accidents such as core meltdown and hydrogen explosion, resulting in a significantly higher accident level. Therefore, studying the mechanical performance of a containment under high temperature and high internal pressure is relevant to the safety of NPPs. Based on similarity principles, the 1:3.2 scale model of a prestressed concrete containment vessel (PCCV) of a NPP was designed. The loading method, which considers the thermal-pressure coupling conditions, was used. The mechanical response of the PCCV was investigated with a simultaneous increase in internal pressure and temperature, and the failure mechanism of the PCCV under thermal-pressure coupling conditions was revealed.