• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(1)
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• pp.149-154
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• 1998

A subcritical reactor driven by a linear proton accelerator has been considered as a nuclear waste incinerator at Korea Atomic Energy Research Institute(KAERI). Since the multiplication factor of a subcritical reactor is less than unity, to compensate exponentially decreasing fission neutrons from spallation reactions are essentially required for operating the reactor in its steady state. furthermore, the profile of accelerator beam currents is very important in controlling a subcritical reactor, because the reactor power varies in accordance of the profile of external neutrons. We have developed a code system to find numerical solutions of reactor kinetics equations, which are the simplest dynamic model for controlling reactors. In a due course of our previous numerical study of point kinetics equations for critical reactors, however, we learned that the same code system can be used in studying dynamic behavior of the subcritical reactor. Our major motivation of this paper is to investigate responses of subcritical reactors for small changes in thermal hydraulic parameters. Building a thermal hydraulic model for the subcritical reactor dynamics, we performed numerical simulations for dynamic responses of the reactor based on point kinetics equations with a source term. Linearizing a set of coupled differential equations for reactor responses, we focus our research interest on dynamic responses of the reactor to variations of the thermal hydraulic parameters in transient phases.

• Kyungpook Mathematical Journal
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• 제62권1호
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• pp.1-28
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• 2022

In this paper, we define the G-Brauer algebras $D^G_f(x)$, where G is a cyclic group, called cyclic G-Brauer algebras, as the linear span of r-signed 1-factors and the generalized m, k signed partial 1-factors is to analyse the multiplication of basis elements in the quotient $^{\rightarrow}_{I_f}^G(x,2k)$. Also, we define certain symmetric matrices $^{\rightarrow}_T_{m,k}^{[\lambda]}(x)$ whose entries are indexed by generalized m, k signed partial 1-factor. We analyse the irreducible representations of $D^G_f(x)$ by determining the quotient $^{\rightarrow}_{I_f}^G(x,2k)$ of $D^G_f(x)$ by its radical. We also find the eigenvalues and eigenspaces of $^{\rightarrow}_T_{m,k}^{[\lambda]}(x)$ for some values of m and k using the representation theory of the generalised symmetric group. The matrices $T_{m,k}^{[\lambda]}(x)$ whose entries are indexed by generalised m, k signed partial 1-factors, which helps in determining the non semisimplicity of these cyclic G-Brauer algebras $D^G_f(x)$, where G = ℤ_r.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.1097-1104
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• 2023

A preliminary criticality analysis for novel pyrochemical apparatuses for the reprocessing of mixed uranium-plutonium nitride spent nuclear fuel from the BREST-OD-300 reactor was performed. High-temperature processing apparatuses, "metallization" electrolyzer, refinery remelting apparatus, refining electrolyzer, and "soft" chlorination apparatus are considered in this work. Computational models of apparatuses for two neutron radiation transport codes (MCU-FR and MCNP) were developed and calculations for criticality were completed using the Monte Carlo method. The criticality analysis was performed for different loads of fissile material into the apparatuses including overloading conditions. Various emergency situations were considered, in particular, those associated with water ingress into the chamber of the refinery remelting apparatus. It was revealed that for all the considered computational models nuclear safety rules are satisfied.

• 정보처리학회논문지A
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• 제12A권4호
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• pp.305-312
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• 2005

본 논문은 알고리즘 레벨에서 FPGA를 이용하여 에너지 효율이 높은 기법을 제안한다. 제안한 기법을 기반으로 FPGA와 행렬곱셈용 신호처리응용을 위한 고효율 설계 기술을 제안한다. 또한 이러한 신호처리응용 수행시 지연시간과 에너지 효율 측면에서의 FPGA 성능을 분석한다. Xilinx Virtex-II를 대상으로 Virtex-II Pro와 Texas Instrument TMS320C6415에 내장되는 Power PC 코어에서 구동되는 Xilinx library와 기존 알고리즘을 본 논문 기법과의 성능 비교를 수행한다. 성능 비교는 high-level에서 에너지와 지연 시간에 대한 유도 공식을 통한 추정치와 low-level 시뮬레이션을 통해 평가하였다. FFT에 대해 본 논문에서 제안한 기법은 Xilinx library와 DSP에 비해 각각 $60\%,\;56\%$ 적은 에너지를 소모한다는 결과를 얻었다. 또한 임베디드 프로세서와 비교해 EAT지수에서 10배의 개선을 보여준다. 위와 같은 결과는 FPGA가 DSP나 임베디드 프로세서에 비해 월등한 성능을 보여준다는 견해에 결정적인 단서가 된다 또한, 이는 FPGA가 앞의 두 종류의 디바이스에 비해 더 적은 전력을 소모하면서 동시에 더 나은 성능을 보인다는 사실을 보여준다.

• 디지털융복합연구
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• 제10권6호
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• pp.275-281
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• 2012

본 연구는 태스크 온톨로지를 이용한 자동차부품 추천시스템 개발 방법을 제안하였다. 제안한 지능형 추천 시스템은 자동차 부품 조립과정을 학습하도록 하였으며, 자동차부품 추천을 위하여 부품들을 온톨로지 방법으로 구축하였다. is-a Relationship 기반 hierarchical Taxonomy를 이용하여 자동차 엔진을 구성하고 있는 각각의 부품들 사이의 관계를 설정하였다. 각각의 부품은 자동차 전문가의 지식에 의해 각기 다른 가중치 값을 가지고 있게 된다. 가중치는 자동차 추천시스템의 사용자들이 직접 사용하면서 선택한 횟수와 가중치의 곱 연산을 이용한 결과 값을 시스템 내에서 기록하여 순서를 작성하고 결과적으로 우선순위(priority)가 높은 순서부터 사용자에게 출력함으로써 어느 부품의 어느 요소가 중요한지 쉽게 파악할 수 있도록 하였다. 자동차부품 지능형 추천시스템은 사용자가 쉽게 접근하기 어려운 자동차 부품관련 부분을 생성된 데이터를 바탕으로 임의의 부품을 선택했을 때 해당 부품과 밀접한 관계를 가진 부품을 표현하여 특별히 전문적인 지식 없이도 손쉽게 자동차 부품의 조립 및 쓰임새와 중요성을 알 수 있게 해주는 시스템이다.

• Nuclear Engineering and Technology
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• 제52권9호
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• pp.1881-1895
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• 2020

The theoretical aspects behind the reactor depletion capability of the Monte Carlo code MCS developed at the Ulsan National Institute of Science and Technology (UNIST) and practical results of this depletion feature for a Material-Testing Reactor (MTR) with plate-type fuel are described in this paper. A verification of MCS results is first performed against MCNP6 to confirm the suitability of MCS for the criticality and depletion analysis of the MTR. Then, the dependence of the effective neutron multiplication factor to the number of axial and radial depletion cells adopted in the fuel plates is performed with MCS in order to determine the minimum spatial segmentation of the fuel plates. Monte Carlo depletion results with 37,800 depletion cells are provided by MCS within acceptable calculation time and memory usage. The results show that at least 7 axial meshes per fuel plate are required to reach the same precision as the reference calculation whereas no significant differences are observed when modeling 1 or 10 radial meshes per fuel plate. This study demonstrates that MCS can address the need for Monte Carlo codes capable of providing reference solutions to complex reactor depletion problems with refined meshes for fuel management and research reactor applications.

• 전기학회논문지P
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• 제55권3호
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• pp.141-145
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• 2006

The line current problem(2-dimensional space : point source) is not easy to analyze the magnetic field using the standard finite element method(FEM), such as overhead trolley line or transmission line. To supplement such a defect this paper is proposed the coupling scheme of analytical solution and FEM. In analysis of the magnetic field using the standard FEM. If the current region is a relatively small compared to the whole region. Therefore the current region must be finely divided using a large number of elements. And the large number of elements increase the number of unknown variables and the use of computer memories. In this paper, an analytical solution is suggested to supplement this weak points. When source is line current and the part of interest is far from line current, the analytical solution can be coupling with FEM at the boundary. Analytical solution can be described by the multiplication of two functions. One is power function of radius, the other is a trigonometric function of angle in the cylindrical coordinate system. There are integral constants of two types which can be established by fourier series expansion. Also fourier series is represented as the factor to apply the continuity of the magnetic vector potential and magnetic field intensity with tangential component at the boundary. To verify the proposed algorithm, we chose simplified model existing magnetic material in FE region. The results are compared with standard FE solution. And it is good agreed by increasing harmonic order.

• 한국습지학회지
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• 제14권3호
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• pp.317-328
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• 2012

본 연구의 목적은 범용토양유실예측공식을 활용하여 모형의 적정성을 분석하고, 그 자료를 축적하는데 있다. 봉동 수위관측소의 유역면적은 $342.27km^2$이며, 유역에서의 유사유출량을 모의하고 이를 실측치와의 비교 분석하였다. 또한 토양침식량 산정에 있어 가장 큰 영향을 미치는 강우침식인자를 산정하기 위해 연도별 강우사상을 활용하였고, 연평균토양침식량 산정을 위해 공간적인 분포를 나타낼 수 있는 격자기반의 토양침식도를 생성하여 산정하였다. 토양침식도($30m{\times}30m$)는 강우침식인자(R), 지형인자(LS), 토양침식인자(K), 식생피복인자(C), 침식조절인자(P)를 ArcView Map Calculator에서 각각의 인자들을 곱하여 생성하였다. 그 결과 대부분의 유역에서 토양침식이 이루어지지 않음을 확인할 수 있었다.

• 한국실내디자인학회논문집
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• 제24권6호
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• pp.229-239
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• 2015

The 21st century is a multiplication age and social and cultural phenomena have become diverse and peoples' desires and individuality have become important. Accordingly, the sensibility that reflects human taste is also required in the exhibition space. The exhibitions in this age induce the direct cognition of senses or take interactive forms that contact diverse media and react. The purpose of this research is to define the concept of haptic presentation method in which the audience perceive in the exhibition space by themselves and the visual elements spread into other senses and perceive complexly, and to present the directional nature. To conduct this research, first, this researcher recognized that haptic sensory experiential research by analyzing the roles and transition history of exhibition space is needed for the present age Second, based on philosophical theories, four haptic sensory expression characteristics (medium nature, experiential nature, attractiveness, sensitiveness) were derived by substituting Giles Deleuze's four haptic spatial characteristics (grasping short distance, dispersed gaze, cognition of bodily movement, formation of synesthesia through complex senses) and six formative factors of exhibition space (space, form, size, light, quality of materials, and color). And the effective exhibition presentation methods were analyzed through six cases of experiential exhibition spaces. Accordingly, what matters in the experiential exhibition space is to produce the four characteristics: medium nature, experientiality, attractiveness, and sensitiveness in equilibrium. It is necessary for the designers to reflect it appropriately in producing so that the audience can think and experience by themselves. Accordingly, in this thesis, it could be seen that to produce the haptic production characteristics in the experiential exhibition space in equilibrium is the important factor in the experiential exhibition space. In conclusion, experiences in the exhibition space should be approached with the transcendental haptic presentation method by which even the space of actually unexperienced cognition can be expanded and experienced through the metastasis and tension of various senses. Also, researches on such senses should be developed continuously, and this researcher expects that this will become a stimulant to present a new directivity.

• Safety and Health at Work
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• 제6권3호
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• pp.200-205
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• 2015

Background: Construction activity has made considerable breakthroughs in the past two decades on the back of increases in development activities, government policies, and public demand. At the same time, occupational health and safety issues have become a major concern to construction organizations. The unsatisfactory safety performance of the construction industry has always been highlighted since the safety management system is neglected area and not implemented systematically in Indian construction organizations. Due to a lack of enforcement of the applicable legislation, most of the construction organizations are forced to opt for the implementation of Occupational Health Safety Assessment Series (OHSAS) 18001 to improve safety performance. Methods: In order to better understand factors influencing the implementation of OHSAS 18001, an interpretive structural modeling approach has been applied and the factors have been classified using matrice d'impacts croises-multiplication $appliqu{\acute{e}}$ a un classement (MICMAC) analysis. The study proposes the underlying theoretical framework to identify factors and to help management of Indian construction organizations to understand the interaction among factors influencing in implementation of OHSAS 18001. Results: Safety culture, continual improvement, morale of employees, and safety training have been identified as dependent variables. Safety performance, sustainable construction, and conducive working environment have been identified as linkage variables. Management commitment and safety policy have been identified as the driver variables. Conclusion: Management commitment has the maximum driving power and the most influential factor is safety policy, which states clearly the commitment of top management towards occupational safety and health.