• Nuclear Engineering and Technology
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• v.44 no.6
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• pp.561-586
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• 2012

This paper describes a summary of final prediction results by system-scale safety analysis codes during the OECD/NEA/CSNI ISP-50 exercise, targeting a 50% Direct Vessel Injection (DVI) line break integral effect test performed with the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS). This ISP-50 exercise has been performed in two consecutive phases: "blind" and "open" phases. Quantitative comparisons were performed using the Fast Fourier Transform Based Method (FFTBM) to compare the overall accuracy of the collected calculations. Great user effects resulting from the combination of the possible reasons were found in the blind phase, confirming that user effect is still one of the major issues in connection with the system thermal-hydraulic code application. Open calculations showed better prediction accuracy than the blind calculations in terms of average amplitude (AA) value. A total of nineteen organizations from eleven countries participated in this ISP-50 program and eight leading thermal-hydraulic system analysis codes were used: APROS, ATHLET, CATHARE, KORSAR, MARS-KS, RELAP5/MOD3.3, TECH-M-97, and TRACE.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.53-59
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• 2010

A fatigue damage caused by cyclic load is considered as one of the important failure mechanisms that threaten the integrity of structures and components in a nuclear power plant. In ASME code section III NB, the fatigue analysis procedure and standard S-N curves for the class 1 components are described and these criteria should be met at the design step of components. As the current ASME S-N curves are based on the very conservative assumptions such as a local stress concentration effect, immoderate transient frequencies and a constant Young's modulus, however, they can not precisely address the fatigue behavior of components. In order to find out the technical solution for these problems, a number of researches and discussion have been carried out continuously at home and abroad over the decades. In this study, detailed fatigue analyses for DVI nozzle with various mesh density of finite elements were performed to evaluate effect of stress concentration factors on the fatigue analysis procedure and the excessive conservatism of stress concentration factors are confirmed through the analysis results.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.457-467
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• 2022

Drought has strong local characteristics, an objective definition or standard that can define the progress or severity of drought is needed and to date, many drought-related studies are being conducted around the world. In this study, Standardized Precipitation Index (SPI), which is a representative meteorological drought index, was calculated, and the drought risk index (DRI) that can consider actual drought was applied to the target area, Uiryeong-gun, by applying the drought vulnerability index (DVI) and the drought hazard index (DHI). A method for practical drought evaluation that can establish a water supply system is presented in this study.

• Electronics and Telecommunications Trends
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• v.23 no.3
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• pp.29-39
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• 2008

본 고에서는 밀리미터파(57-66GHz) 대역의 새로운 주파수 자원을 개척하여 국내 기업이 세계 시장을 장악하고 있는 LCD, PDP 및 차대세 DVD 플레이어 등에 적용될 Wireless HD-SDI/DVI와 외장 하드 디스크, 메모리 등 외부 기억 장치와의 자원 공유에 사용될 Multi-Gbps급 Wireless LAN, Wireless PAN, Wireless SAN 등에 적용될 무선 전송 기술 동향이다. 57-66GHz 주파수 대역에 대한 국제 표준화로 Ecma International TC48을 중심으로 활발히 일어나고 있는 표준 기술과 표준화 동향을 살펴본다.

• Defense and Technology
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• no.9 s.283
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• pp.66-73
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• 2002

대부분의 현대 항공기 조종실은 유사한 형태인 HUD, 2개 이상의 MFD, UFC, HOTAS 등으로 구성된다. 앞에서 언급한 바와 같이 최근에는 전투기에도 HMD와 DVI(Direct Voice Input)를 적용하고 있다. 미래의 조종실은 빠르게 발전하고 있는 평면 시현 기술로 인해 HDD는 2010년대에는 15 X 20인치 크기까지 지원이 가능할 것으로 예상되며 HUD가 없어지고 높은 해상도가 넓은 시계영역을 가진 HMD가 없어지고 높은 해상도와 넓은 시계영역을 가진 HMD로 다중 운용(Joing Service Operability) 및 다중 임무 수행이 가능한 조종실이 될 것이며 2025년대에는 레이저 운용에 적합한 조종실로 변화되어 캐노피가 없는 조종실(Windowless Codkpit) 또는 불투명 HMD를 사용한 설계개념으로 발전할 것이다.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.141-149
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• 2021

In this study, an laboratory experiment was performed for prediction technology of water content in the ground using hyperspectral information. And the spectral reflectance with a specific wavelength band was obtained according to the fine and water content. Through it, the spectral information was normalized with the spectral index of the existing literature, and the relationship with the fine and water contents and the reliability of the prediction technology were analyzed. As a result of analysis, the spectral reflectance is decreased when the water and fine contents are increased under the high water contents. In addition, the reliability of prediction technology of water content was evaluated by examining 7 different spectral index calculation methods. Among them, DVI showed relatively high prediction reliability and was superior to other calculation methods in terms of sensitivity.

• Nuclear Engineering and Technology
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• v.41 no.8
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• pp.995-1004
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• 2009

The Advanced Power Reactor 1400 (APR1400) is an evolutionary advanced light water reactor (ALWR) based on the Optimized Power Reactor 1000 (OPR1000), which is in operation in Korea. The APR1400 incorporates a variety of engineering improvements and operational experience to enhance safety, economics, and reliability. The advanced design features and improvements of the APR1400 design include a pilot operated safety relief valve (POSRV), a four-train safety injection system with direct vessel injection (DVI), a fluidic device (FD) in the safety injection tank, an in-containment refueling water storage tank (IRWST), an external reactor vessel cooling system, and an integrated head assembly (IHA). Development of the APR1400 started in 1992 and continued for ten years. The APR1400 design received design certification from the Korean nuclear regulatory body in May of2002. Currently, two construction projects for the APR1400 are in progress in Korea.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2198-2202
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• 2005

In this paper we have presented a condition monitoring method of check valve using neural network. The acoustic emission sensor was used to acquire the condition signals of check valve in direct vessel injection (DVI) test loop. The acquired sensor signal pass through a signal conditioning which are consisted of steps; rejection of background noise, amplification, analogue to digital conversion, extract of feature points. The extracted feature points which represent the condition of check valve was utilized input values of fault diagnosis algorithms using pre-learned neural network. The fault diagnosis algorithm proceeds fault detection, fault isolation and fault identification within limited ranges. The developed algorithm enables timely diagnosis of failure of check valve’s degradation and service aging so that maintenance and replacement could be preformed prior to loss of the safety function. The overall process has been experimented and the results are given to show its effectiveness.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.228-233
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• 2000

The Korean Next Generation Reactor(KNGR) is a Pressurized Water Reactor adopting direct vessel injection(DVI) to optimize the performance of emergency core cooling system(ECCS). In a certain accident, however, pressurized thermal shock(PTS) of the vessel due to the sudden contact with the injected cold water is expected. In this paper, an accident of Main Steam Line Break(MSLB) has been numerically investigated with direct vessel injections and an increased volume flow rate in some cold legs. Using FLUENT code, temperature distributions of the fluid in the downcomer and of reactor vessel including the core region have been calculated, together with the distribution of convective heat transfer coefficient(CHTC) at the cladding surface of the reactor vessel. The result shows that some parts of the core region of the reactor vessel have higher temperature gradient expressing higher thermal stress.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.39-43
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• 2003

학회는 학술지식정보자원의 최신정보에 대한 접근 점이지만, 대규모 학회를 제외하고는 정보 수집과 서비스 면에서 재래식 방법을 벗어나지 못하고 있다. 더구나, 최근에는 각 학회 자체 업무 중 발생하는 회원관리, 논문투고, 심사와 같은 제반업무와, 발간되는 학술정보에 대한 정보화를 수행하고자 하는 학회의 열의가 급격히 증가하고 있는 추세이나, 학회의 재정상 적극적으로 이행하지 못하고 있는 실정이다. 이에 KISTI는 한국과학기술정보연구원은 국가차원의 학회 정보화 사업의 일환으로 학회정보 유통체제 전 과정을 온라인화하고 쉽게 관리할 수 있도록 한 $\boxDr$KISTI-ACOMS(KISTI-Article Contribution Management System: KISTI-학회논문투고관리시스템) $\boxDr$KISTI-ACOMS(KISTI-Article Contribution Management System)$\boxUl$ 을 개발하여 2001년부터 학회에 무상으로 보급하여 왔다. 최근에는 학회의 KISTI-ACOMS를 이용하고자 하는 요청이 더욱 확대되고 있어, KISTI는 많은 학회 특성을 의견수렴하여, KISTI-ACOMS의 표준화를 목표로 보완해 나가고 있다.