• 제목/요약/키워드: far-field environment

검색결과 194건 처리시간 0.023초

Development of Reference Scenarios Based on FEPs and Interaction Matrix for the Near-surface LILW Repository

  • Lee, Dong-Won;Kim, Chang-Lak;Park, Joo-Wan
    • Nuclear Engineering and Technology
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    • 제33권5호
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    • pp.539-546
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    • 2001
  • Systematic procedure of developing radionuclide release scenarios was established based on FEP list and Interaction Matrix for near-surface LILW repository. FEPs were screened by experts'review in terms of domestic situation and combined into scenarios on the basis of Interaction Matrix analysis. Under the assumption of design scenario, The system domain was divided into three sections: Near-field, Far-field and Biosphere. Sub-scenarios for each section were developed, and then scenarios for entire system were built up with sub-scenarios of each section. Finally, sixteen design scenarios for near-surface repository were evaluated A reference scenario and other noteworthy scenarios were selected through experts'scenario screening.

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축소 모델을 이용한 수동 루프 송전선 자기장 저감율 분석 (Analysis of ELF Magnetic Field Reduction Ratio on Passive Loop Using Scale Down Model of Transmission Line)

  • 조연규;명성호;이재복;장석훈
    • 한국전자파학회논문지
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    • 제17권12호
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    • pp.1231-1239
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    • 2006
  • 본 연구는 수동 루프 축소 시험 장치를 이용하여 수동 루프 유형별 자기장 저감 효과를 분석하였다. 본 연구에서는 수직 2회선 선로 및 수평 선로를 대상으로 실험을 통하여 향후 실증 시험 선로에 적용할 수동 루프의 자기장 저감 효과를 검토하였다. 그 결과 수동 루프 채용으로 선로 리액턴스 보상이 없어도 50 % 이상의 송전 선로의 자기장 저감 효과를 얻을 수 있음을 확인함으로써 실증 선로 수동 루프 적용 방안을 확보하였다. 대부분 우리나라 송전 선로에 채용되는 수직 2회선 선로에서는 수평 루프보다는 수직 루프가 자기장 저감율에 보다 효과적이었으며 차폐 영역에서도 근거리뿐만 아니라 원거리까지도 효과가 좋음을 알 수 있었다. 또한, 수동 루프를 3 턴으로 설치하는 경우가 1 턴에 비해 2배정도 자기장 저감 효과가 있음을 확인하였다.

다중경로환경에서 바닥고정형 선배열센서를 이용한 근거리표적의 위치추정기법 (Near-field Target Localization Using Bottom-mounted Linear Sensor Array in Multipath Environment)

  • 이수형;류창수;이균경
    • 한국음향학회지
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    • 제19권7호
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    • pp.7-14
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    • 2000
  • 본 논문에서는 바닥고정형 선배열센서를 이용하여 다중경로 신호를 이용한 근거리표적의 위치추정 알고리즘을 제안하였다. 다중경로를 통하여 근거리 표적의 신호가 센서에 도달하는 경우 각 신호의 원추각이 다르므로 신호들의 원추각과 시간차를 추정해서 3차원 표적의 위치를 추정할 수 있다. 원거리표적으로 가정하고 추정한 원추각과 신호들의 시간차에 대한 관계식을 유도하였으며 이들을 연립하여 표적의 위치를 추정하였다. 그러나 표적이 위치한 기하학적인 위치에 따라 신호들의 원추각이 거의 같아지는 지점이 존재한다. 이 경우 부가적인 1차원 탐색으로 표적의 위치를 추정하였다.

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An Exploratory Study on the Usage of Internet Technologies and Tools in Educational Working Environment of Developing Countries: A Case of Pokhara University in Nepal

  • Shrestha, Deepanjal;Jeong, Seung Ryul
    • 인터넷정보학회논문지
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    • 제16권4호
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    • pp.101-110
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    • 2015
  • $21^{st}$ century has seen a tremendous advancement in the field of Information and Communication Technology. The commercial utilization of Internet tools and technologies has brought change in the traditional working environment. The functioning in an electronic environment is far more complicated than working in traditional environment and this brings many challenges, threats and potential problems. In this paper we analyze the challenges, threats and potential problems in the working environment of Pokhara University due to application of Internet tools and technology. We have chosen four basic areas on the basis of use that include web resources, electronic mails, social sites and P2P technologies. The main focus is to analyze the impact on work place productivity, social interaction, use and abuse of technology and legal issues associated with them. We, finally summarize the findings and offer solutions and recommendations from the observed data based on direct survey conducted in Pokhara University, Nepal.

수중반사파 환경에서의 근접음장 홀로그래피 적용에 대한 오차 고찰 (Error Investigation in use of Near-field Acoustic Holography in the Underwater Environment of Reflected Wave)

  • 이종주;강명환;한승진;정현주;배수룡;정우진
    • 한국소음진동공학회논문집
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    • 제24권12호
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    • pp.969-976
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    • 2014
  • Nowadays, it is required for naval ships to estimate 3D underwater radiated noise pattern in all direction at peak frequencies of hull vibration for the reduction of being detected and doing the effective operation. For this purpose, the numerical method has to be developed to calculate 3D underwater radiated noise pattern with experimental data. It is very difficult to obtain the experimental data for the real ship. Alternative to get the experimental results is to use NAH(near-field acoustic holography) in acoustic tank with experimental model. Application of NAH in acoustic tank for the experimental model needs some investigation of reflection wave from the wall of the acoustic tank and unmeasured zone of the experimental model due to the supporting structure for it. In this study, the effect of reflection wave in the acoustic tank and unmeasured area of the experimental model when using the NAH was investigated with experiment and numerical model. From these, it is known for the error due to reflection wave can be reduced when the distance between the measurement plane and source is being shorten. Also, unmeasured area of the experimental model gives rise to some error in the estimation of the far-field acoustic pressure.

International Exchanges for Aspiring Students in Engineering Field

  • Sato, Takashi;Sakamoto, Shuichi;Shimizu, Tadaaki;Ikeda, Hideki;Oka, Tetsuo
    • 공학교육연구
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    • 제15권4호
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    • pp.3-7
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    • 2012
  • In 1996, the Faculty of Engineering, Niigata University, Japan entered an era of open student-exchange with Otto-von-Guericke-University Magdeburg, Germany. Thus far, more than 50 of our students have devoted anywhere from three months, to an entire year of their courses, to collaborative efforts with fellow students, (-and some cases, the local citizenry) -in their native environment experiencing unfamiliar education systems and cultures.

Hidden Monsters in the Submillimeter

  • Wang, Wei-Hao
    • 천문학회보
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    • 제37권2호
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    • pp.232.2-232.2
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    • 2012
  • Submillimeter Galaxies (SMGs) are high-redshift galaxies undergone extremely intense starbursts. Their UV radiation is heavily extinguished by dust and is re-radiated in the far-IR and submillimeter. They are thought to be progenitors of present-day giant elliptical galaxies and can be tracers of the highest density environment at high redshift. However, because of the low angular resolution of existing single-dish submillimeter telescopes, the progress in understanding the SMG population has been remarkably slow. In this talk, I will outline the outstanding issues in this field, and introduce our Submillimeter Array interferometric studies of SMGs. I will also discuss possible new research that will be enabled by next-generation instruments such as ALMA and LMT.

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Proton Irradiation Effects on GaN-based devices

  • Keum, Dongmin;Kim, Hyungtak;Cha, Ho-Young
    • Journal of Semiconductor Engineering
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    • 제2권1호
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    • pp.119-124
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    • 2021
  • Along with the needs for feasibility in the field of space applications, interests in radiation-hardened electronics is growing rapidly. Gallium nitride (GaN)-based devices have been widely researched so far owing to superb radiation resistance. Among them, research on the most abundant protons in low earth orbit (LEO) is essential. In this paper, proton irradiation effects on parameter changes, degradation mechanism, and correlation with reliability of GaN-based devices are summarized.

On the New Design of a 4-Port TEM Waveguide with a Higher Cutoff Frequency and Wider Test Volume

  • Jeon, Sangbong;Yun, Jaehoon;Park, Seungkeun
    • ETRI Journal
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    • 제34권4호
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    • pp.621-624
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    • 2012
  • A new miniaturized 4-port waveguide generating a transverse electromagnetic wave is proposed. The waveguide presents enhanced performance of higher field uniformity in extended test volume up to an increased test frequency limit compared to that of the conventional 2-port waveguide. The advantageous features of the proposed waveguide have been obtained through a new design scheme based on effective miniaturization maintaining good impedance matching. Consequently, we can provide a more accurate electromagnetic compatibility test method, covering larger devices operating in higher frequencies, which is a marked improvement upon the conventional approaches.

Maemi Dual Field Telescope System (MDFTS) : New survey facility of Kyung Hee Astronomical Observatory

  • Ahn, Hojae;Kim, Na Yeon;Kim, Dohoon;Pak, Soojong;Im, Myungshin
    • 천문학회보
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    • 제44권2호
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    • pp.79.2-79.2
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    • 2019
  • We introduce Maemi Dual Field Telescope System (MDFTS) which is newly installed at Kyung Hee Astronomical Observatory (KHAO). MDFTS consists of two telescope tubes (40cm and 10cm), whose observing fields are aligned with different field of view, 15' x 11' and 83' x 63' respectively. We present the specification of instruments (telescope, mount, camera, and filter system) and the observation environment of KHAO. We expect that MDFTS can be used for transient survey e.g. Intensive Monitoring Survey of Nearby Galaxies (IMSNG). Based on observations conducted so far, the limiting magnitude of 40cm telescope in B-band is B_lim ~ 16 mag at 5-σ detection with 150 seconds total integration time under dark and clear observing condition. Also the integrated observing software for MDFTS, KAOS40 is now under developing.

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