• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4722-4730
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• 2022

This paper introduces a new point depletion-based source term calculation code named BESNA (Bateman Equation Solver for Nuclear Applications), which is aimed to estimate nuclide inventories and source terms from spent nuclear fuels. The BESNA code employs a new modified CE/CM (Constant Extrapolation - Constant Midpoint) predictor-corrector scheme in depletion calculations for improving computational efficiency. In this modified CE/CM scheme, the decay components leading to the large norm of the depletion matrix are excluded in the corrector, and hence the corrector calculation involves only the reaction components, which can be efficiently solved with the Talyor Expansion Method (TEM). The numerical test shows that the new scheme substantially reduces computing time without loss of accuracy in comparison with the conventional scheme using CRAM (Chebyshev Rational Approximation Method), especially when the substep calculations are applied. The depletion calculation and source term estimation capability of BESNA are verified and validated through several problems, where results from BESNA are compared with those calculated by other codes as well as measured data. The analysis results show the computational efficiency of the new modified scheme and the reliability of BESNA in both isotopic predictions and source term estimations.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1398-1406
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• 2024

The control rod worth is a key safety parameter required to be measured in commercial pressurized water reactors (PWRs). Conventionally, the control rod worth is measured after reaching the critical state, which occupies the considerable time in the zero-power physics test. In this study, an efficient control-rod worth measurement technique has been proposed based on the improved neutron-source multiplication method, which can be implemented with the source-range detector count rates in the subcritical states. Moreover, the noise reduction technique has been adopted to smooth the large fluctuation existing in the original signals. In order to verify the engineering performance of the proposed measurement technique, the measured source-range detector count rates during the rod withdrawal process before reaching critical state in a CNP1000 reactor have been employed. It demonstrated that almost all estimated results of control rod worth satisfy the engineering acceptance criteria, except one control rod with the relative difference over 10 %, which indicates the capability of the proposed method in estimating control rod worth.

• 한국소음진동공학회논문집
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• 제22권8호
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• pp.777-783
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• 2012

진동 인텐시티는 진동시스템에서 진동원의 위치를 찾는데 사용되어 왔다. 벡터 표현법 사용에 의해 파워흐름의 원인과 진동에너지 전달경로가 밝혀질 수 있다. 그러나, 판과 같은 구조물의 넓은 면적으로 인해 벡터 가시화를 사용하여 명확한 전달경로를 알아낼 수 없었다. 실험적으로 큰 면적의 물체에서는 측정점의 수가 늘어나게 된다. 이것은 측정에 많은 시간이 요구된다. 이번 연구에서는 FEM과 실험에 의한 모든 면에서 파워흐름 전달경로를 분명하게 가리키기 위해 유선 표현법이 사용되었다. 진동 인텐시티 전달경로를 분명하게 향상시키기 위해 실험과 FEM으로부터의 유선 표현을 비교하였다. 또한 FEM과 실험의 개선된 전달경로 가시화를 기존의 벡터표현과 비교하였다. 이 유선 가시화는 큰 표면을 갖는 판과 같은 구조물에 대해 진동원과 상세한 에너지 전달경로를 확인하는데 유용하다. 그 뿐만 아니라, 이 가시화 방법은 실험과 FEM 해석에 대해 많은 측정점을 필요로 하지 않는다.

• 아태비즈니스연구
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• 제11권3호
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• pp.169-184
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• 2020

Purpose - This research is intended to analyze the current status and problems of tax benefits in the R&D sector and suggest ways to improve tax credit for research and manpower development expenses when various countries fiercely develop efforts to enhance national competitiveness through increased investment in R&D Design/methodology/approach - This study will examine the current status of the tax support system for domestic and foreign R&D, and suggest improvement measures to expand research and development activities in the future. Findings - First, a plan may be considered to abolish and perpetuate the sunset deadline for tax credit for research and manpower development expenses as in the case of the United States and Japan. This perpetuation can be a proactive measure to actively support long-term R & D investment in companies facing economic decisions under uncertainty. Second, it should be revised to raise the tax credit rate of large corporations, which are shrinking every year, compared to SMEs, so that both large corporations and SMEs can improve their international competitiveness and secure excellent technologies through R & D. Finally, the target technologies for each new growth engine and source technology should be expanded to various fields, including national cybersecurity enhancement technology, aviation engine technology, carbon emission and global cooling technologies, which are areas of interest in major overseas R&D countries, to help active R&D and investment in these areas. Research implications or Originality - This study can find a contribution in comparing and analyzing the national R&D tax support system and presenting improvement measures at a time when the benefits of tax credit for research and manpower development expenses of large companies are decreasing due to frequent tax law revisions and the government's factors of increasing tax revenues. In addition, recent research and development items and research technologies of foreign countries were analyzed by Nature's top 10 major science and technology issues, and advanced technologies that should be applied to target technology areas by new growth engine and source technology were specifically investigated and presented.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.2-4
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• 2010

Due to rapid progress in the performance of high-end computers, numerical prediction of fluid flow and flow-induced sound is expected to become a vital tool for aero- and hydro- dynamic design of various flow-related products. This presentation focuses on the applications of large-scale numerical simulations to complex engineering problems with a particular emphasis placed on the low-speed flows. Flow field computations are based on a large eddy simulation that directly computes all active eddies in the flow and models only those eddies responsible for energy dissipations. The sound generated from low-speed turbulent flows are computed either by direct numerical simulation or by decoupled methods, according to whether or not the feedback effects of the generated sound onto the source flow field can be neglected. Several numerical examples are presented in order to elucidate the present status of such computational methods and discussion on the future prospects will also be given.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권2호
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• pp.620-636
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• 2015

Survivability is a necessary property of network system in disturbed environment. Recovery ability is a key actor of survivability. This paper concludes network survivability into a novel composite metric, i.e. Network Recovery Degree (NRD). In order to measure this metric in quantity, a concept of Source-Destination Pair (SD Pair), is created to abstract end-to-end activity based on end nodes in network, and the quality of SD Pair is also used to describe network performance, such as connectivity, quality of service, link degree, and so on. After that, a Survivability Test method in large scale Network based on SD pairs, called STNSD, is provided. How to select SD Pairs effectively in large scale network is also provided. We set up simulation environment to validate the test method in a severe destroy scenario and evaluate the method scalability in different large scale network scenarios. Experiment and analysis shows that the metric NRD correctly reflects the effort of different survivability strategy, and the proposed test method STNSD has good scalability and can be used to test and evaluate quantitative survivability in large scale network.

• 시큐리티연구
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• 제34호
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• pp.259-278
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• 2013

21세기 정보통신기술의 발달과 급격한 인터넷의 확산으로 비밀 출처정보에서만 수집이 가능했던 정보(Information)가 인터넷을 통해 쉽게 검색이 가능하게 되었다. 공개정보(Open Source)가 폭발적으로 증가하면서 정보수집활동에 큰 변화가 일어나고 있으며, 이러한 변화는 국가정보기관에서의 정보수집활동에도 영향을 미치고 있다. 공개출처정보(Open Source Intelligence: OSINT)는 이렇게 넘쳐나는 정보를 효과적으로 처리하고 분석하기위해 등장하였다. OSINT는 주로 9.11테러 이후에 빠르게 적용되었으며, 국가정보기관에서는 이와 관련된 연구와 기술개발에도 적극 참여하고 있다. 이렇게 서구국가에서는 OSINT의 중요성을 인지하고 공개정보(Open Source)를 분석하는 일이 최우선 순위로 떠오르고 있다. 하지만 국내에서는 공개정보(Open Source)의 중요성에 대한 인식이 미흡한 실정이다. 본 연구에서는 OSINT를 소개하고 중요성을 제고하는 것을 목적으로 하였다. 감당하기 힘들 정도로 늘어나는 많은 양의 공개정보(Open Source)를 효과적으로 이용하기 위하여 OSINT의 운용사례와 방법을 소개하고 중요성을 논의하였다. 이는 국가안보를 위협하는 테러뿐만 아니라 각종 범죄를 효과적으로 대응하기위한 방안이기도 하다.

• 한국대기환경학회지
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• 제20권3호
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• pp.317-330
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• 2004

The Purpose of this study was to develop the P $M_{2.5}$ source Profiles, which are mass abundances (fraction of total mass) of a chemical species in P $M_{2.5}$ source emissions. The source categories studied were soil, road dust, gasoline and diesel vehicles, industrial source, municipal incinerator, coal-fired power plant, biomass burning, and marine. The chemicals analyzed were ions. elements. and carbons. From this study, soil source had the crustal components such as Si, hi, and Fe. In the case of road dust. Si, OC, Ca, Fe had large abundances. The abundant species were S $O_4$$^{2-}$, C $l^{[-10]}$ , N $H_4$$^{+}$, and EC in the gasoline vehicle and EC, OC, C $l^{[-10]}$ , and S $O_4$$^{2-}$ in the diesel vehicle. The main components were S $O_4$$^{2-}$, S N $H_4$$^{+}$, and EC in the industrial source using bunker C oil as fuel, C $l^{[-10]}$ , N $H_4$$^{+}$, Fe, and OC in the municipal incinerator source, and Si, Al, S $O_4$$^{2-}$, and OC in the coal -fired power plant source. In the case of biomass burning, OC, EC, and C $l^{[-10]}$ were mainly emitted. The main components in marine were C $l^{[-10]}$ , N $a^{+}$, and S $O_4$$^{2-}$.EX> 2-/.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1134-1136
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• 2002

This paper proposes a FSK(Frequency Shift Keying) transmitter which has a inverter for power amplification instead of linear amplifier. As it can generate large signal using resonant circuit under the low voltage source even if the impedance of antenna is large as like a loop antenna of TWC(Train to Way-side Communication) system. In this paper, the proposed fully digital controlled transmitter including FSK modulation is presented and its control schemes are discussed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.133-136
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• 2000

A new Op-Amp output buffer is presented for driving large-size LCD panels. The proposed Op-Amp is designed by combining a common source and a common drain amplifier to have a high slew rate and to minimize the quiescent current. The proposed circuits are simulated in a high-voltage 0.6${\mu}{\textrm}{m}$ CMOS process, dissipates only 20${\mu}{\textrm}{m}$ static current, and have 83dB open-loop DC gain and 60$^{\circ}$phase margin.