• Title/Summary/Keyword: Accelerators

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The Status and Prospects of Accelerators in Radiation Industries (방사선 산업용 가속기의 현황과 전망)

  • Chai, Jong-Seo
    • Journal of Radiation Industry
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    • v.6 no.1
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    • pp.101-110
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    • 2012
  • This paper is described the review of several selected accelerators and the use of accelerators in various purposes. The electrostatic accelerators and RF accelerators have been developed before the second world war for the purpose of basic research of physics mainly. RF driven accelerators have been achieved higher energy and applied in medical and industrial use after 1980's. Accelerators have improved incorporating new technologies : axial and horizontal injection, stripping extraction, superconducting RF, computer control, superconducting magnet etc.. Also recent key technologies as BT and NT make the expansion of applications of the accelerators.

Particle Acceleration by High Power (> TW) Femtosecond Lasers in Plasmas (고출력 펨토초 레이저와 플라즈마를 이용한 입자가속)

  • Suk, H.;Hafz, N.;Kim, C.B.;Kim, G.H.;Kim, J.U.;V. Kulagin;Lee, H.J.;Kim, J.C.;Ko, I.S.;Hahn, S.J.;Pae, G.H.
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.07a
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    • pp.62-62
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    • 2003
  • Charged particles can be accelerated to relativistic high energies by high power (> terawatt) laser beams. We have a research project on laser and plasma-based advanced accelerators in Center for Advanced Accelerators at Korea Electrotechnology Research Institute (KERI), in which the 2 TW (1.4 J/700 fs) Ti:sapphire/Nd:glass hybrid laser system and a He plasma will be used for particle acceleration experiments. In this presentation, we introduce the ongoing research activities and the planned experiments at KERI.

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A Study on the Investment Effect of Public Accelerator (공공 액셀러레이터 투자 효과에 관한 연구)

  • Hong, JungOh;Kim, Moon-Kyum
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.3
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    • pp.19-31
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    • 2022
  • Currently, the role of public accelerators in the domestic accelerator market is gradually expanding. Accordingly, in order to establish relevant policies properly, it is necessary to check the effect and validity of public accelerators' investment. However, there is no quantitative research conducted on domestic accelerators, using their financial data, as domestic accelerators have a short history and quantitative data on them are not disclosed. Therefore, this study conducted an empirical analysis with financial data of the startups that received equity investments from public accelerators to confirm the effect of public accelerators'investment in startups. A regression analysis was conducted with financial data from 112 startups that acquired investments from public accelerators in the period of 2016~2020. And the findings are as follows: First, it was found that the initial investment of public accelerators had an effect on the growth and profitability of startups. Specifically, it was confirmed that the initial investment of public accelerators had a positive (+) effect on sales growth rates and total asset growth rates, which are growth indicators. Second, it was found that the joint investment of public accelerators had a significant positive (+) effect on profit margin, an indicator of profitability, rather than on growth. Therefore, it is deemed that it will be a great force for growth if investment in the early-stage startups that showed significant investment results in this study is continuously expanded in combination with support projects, which are a strength of public accelerators. Since this study has confirmed the investment effect of public accelerators, it is deemed necessary to actively promote policies that direct public accelerators' projects toward improving the performance of startups through joint investment with the private sector and supplementing private accelerators' deficiencies.

Simulation of Amplification Characteristics of Ultrashort Laser Pulse Amplification using Raman Backscattering (라만 후방향 산란을 이용한 레이저 펄스 증폭에서 나타나는 증폭 특성의 시뮬레이션)

  • Kim, Jincheol;Lee, Hae-June;Kim, Guang-Hoon;Kim, Changbum;Kim, Jong-Uk;Hyyong Suk
    • Proceedings of the Optical Society of Korea Conference
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    • 2002.07a
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    • pp.230-231
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    • 2002
  • Recently, analysis of transient Raman backscattering in a plasma reported(2.3) that it is possible to reach 10$\^$17/ W/cm$^2$ for 1 micrometer wavelength laser pulse with a counter-propagating pump pulse. The basic mechanism is like this : whorl the two counter-propagating waves in a plasma satisfy the condition of Raman backscattering, w$\_$0/ : w$\_$1/ + w$\_$p/, energy is transferred from the long pulse to the short pulse via three wave interaction(4). (omitted)

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A Study on Properties of High Blaine Slag Cement for Shotcrete (숏크리트용 고분말도 슬래그 시멘트의 특성)

  • Kim, Jae-Young;Yum, Soo-Kyung;Yoo, Dong-Woo;Choi, Hyun-Kuk
    • Journal of the Korean Ceramic Society
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    • v.47 no.5
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    • pp.357-364
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    • 2010
  • This study was performed to get basic information about properties of high blaine slag cement(HSC) to use shotcrete(or sprayed concrete and mortar). Particle size distribution, setting time and compressive strength test, analysis like as SEM, DSC thermal analysis, XRD was carried out to investigate principle properties of HSC. Setting time of HSC was delayed slightly, but influence of accelerators was more bigger than ordinary portland cement(OPC). Compressive strength of HSC at 28 days was more higher than OPC regardless of using accelerators. Results of analysis showed early period hydration products of HSC is more small and located widely, because of the interface of between cement particle and water is increased as specific surface of cement increase. From the SEM observation and analysis of DSC and XRD results, aluminates accelerators bring on some hydration products like as calcium aluminium hydrates, alkali free accelerators increases ettringite and monosulfates. Aluminates accelerators has a advantage of setting time and early strength, alkali free accelerators increases strength after 7 days.

Automated optimization for memory-efficient high-performance deep neural network accelerators

  • Kim, HyunMi;Lyuh, Chun-Gi;Kwon, Youngsu
    • ETRI Journal
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    • v.42 no.4
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    • pp.505-517
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    • 2020
  • The increasing size and complexity of deep neural networks (DNNs) necessitate the development of efficient high-performance accelerators. An efficient memory structure and operating scheme provide an intuitive solution for high-performance accelerators along with dataflow control. Furthermore, the processing of various neural networks (NNs) requires a flexible memory architecture, programmable control scheme, and automated optimizations. We first propose an efficient architecture with flexibility while operating at a high frequency despite the large memory and PE-array sizes. We then improve the efficiency and usability of our architecture by automating the optimization algorithm. The experimental results show that the architecture increases the data reuse; a diagonal write path improves the performance by 1.44× on average across a wide range of NNs. The automated optimizations significantly enhance the performance from 3.8× to 14.79× and further provide usability. Therefore, automating the optimization as well as designing an efficient architecture is critical to realizing high-performance DNN accelerators.