• 한국게임학회 논문지
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• 제22권1호
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• pp.87-98
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• 2022

4차 산업혁명 관련 기술의 발전과 비대면 서비스 수요 증가로 VR 게임이 주목받고 있다. 본 연구는 VR 게임의 리뷰 데이터를 온라인 게임 플랫폼 스팀(STEAM)에서 수집하고 텍스트 마이닝과 워드 클라우드 분석을 적용해 시대별 트렌드를 분석했다. 연구 결과, 프레즌스와 FPS는 시기와 상관 없이 VR 게임의 특징으로 나타났고, 2016~2017년은 체험과 지각된 비용, 2018~2019년은 FPS와 리듬게임의 수요 증가, 2020~2021년은 스토리와 몰입감이 주요 트렌드로 나타났다. 본 연구는 VR 게임 사용자들이 관심을 보이는 키워드를 시기별로 파악해 VR게임 저변 확대에 기여하고자 한다.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.959-960
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• 2005

• Nuclear Engineering and Technology
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• 제45권4호
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• pp.439-458
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• 2013

REX-10 is a fully-passive small modular reactor in which the coolant flow is driven by natural circulation, the RCS is pressurized by a steam-gas pressurizer, and the decay heat is removed by the PRHRS. To confirm design decisions and analyze the transient responses of an integral PWR such as REX-10, a thermal-hydraulic system code named TAPINS (Thermal-hydraulic Analysis Program for INtegral reactor System) is developed in this study. Based on a one-dimensional four-equation drift-flux model, TAPINS incorporates mathematical models for the core, the helical-coil steam generator, and the steam-gas pressurizer. The system of difference equations derived from the semi-implicit finite-difference scheme is numerically solved by the Newton Block Gauss Seidel (NBGS) method. TAPINS is characterized by applicability to transients with non-equilibrium effects, better prediction of the transient behavior of a pressurizer containing non-condensable gas, and code assessment by using the experimental data from the autonomous integral effect tests in the RTF (REX-10 Test Facility). Details on the hydrodynamic models as well as a part of validation results that reveal the features of TAPINS are presented in this paper.

• 제어로봇시스템학회논문지
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• 제22권5호
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• pp.367-373
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• 2016

In this paper, range measurement performance of LRF (Laser Range Finder) module and image contrast of color CCD camera are evaluated under the aerosol (high temperature steam) environments, which are simulated severe accident conditions of the LWR (Light-Water-Reactor) nuclear power plant. Data of LRF and color CCD camera are key informations, which are needed in the implementation of SLAM (Simultaneous Localization and Mapping) function for emergency response robot system to cope with urgently accidents of the nuclear power plant.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.172-174
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• 1995

About a half of Electric power is generated by nuclear power plants in korea. So, the stable operation of nuclear power plant is very important for suppling the essential national electric power. A S/G(Steam Generator) level control is the most difficult system in PWR(Pressurized Water Reactor) nuclear power plant. Because of the non-linear and the non-nominal response of S/G level control, it Is very difficult to control the level by automatic mode or manual mode. The goal of this study is to establish and verify a advanced control algorithm by analyzing, modelling, stability calculation, controller parameter calculation, simulation for S/G level control system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2495-2497
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• 2000

Level control in the steam generator of a nuclear power plant is important process. But, the low power operation of nuclear power plant causes nonlinear characteristics and non minimum phase characteristics (swell and shrink), change of delay. So, we can't lead good results with conventional PID controller. Particularly, the design of controller with constraints is necessary. This paper introduces MPC(Model Predictive Control) with constraints and designs a good performance MPC controller in spite of the input constraints and nonlinear characteristics, non-minimum phase characteristics

• 한국기계가공학회지
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• 제10권6호
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• pp.134-139
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• 2011

This study was conducted on the characteristics of fluid flow and heat transfer in the ribbed tube used for a steam power plant. It was assumed that the air is incompressible and therefore, its density is not variable according to temperature. In addition, the gravity was ignored. A commercial code of computational fluid dynamics was used and standard k-$\epsilon$ model was used together with the energy equation included to calculate heat transfer. As Reynolds No. was low at the velocity distribution in the axial direction, the air reached hydro-dynamically fully developed region shortly but high Reynolds No. yielded late full hydro-dynamic development. The velocity distribution and non-dimensional temperature distribution were all physically reasonable and thus had a good agreement with the experimental result.

• Journal of the Korean Wood Science and Technology
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• 제22권2호
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• pp.30-36
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• 1994

Steam explosion process is one of the most efficient, pretreatment method for the utilization of lignocellulosic biomass. The carbxymethyl-cellulose(CMC) was prepared with steam exploded wood(EXW), pine(Pinus densiflora) and oak(Quercus mongolica), by standard method using isopropyl alcohol and monochloroacetic acid. The range of water solubility of carboxymethylated pine exploded wood was 45.2~66.8 % and those of oak was 60.7~84.7 %. The degree of substitution(D.S) of carboxymethylated pine exploded wood was 0.11~0.33 and oak exploded wood was 0.48~0.76. The color of carboxymethylated pine and oak exploded wood was brown-black. When carboxymethylated EXW was purified by sulfuric acid, the yield of carboxymethylated wood was lower than non-treated one. However, the color was still brown-black although after delignification. In carboxymethylated EXM prepared after delignification, the water solubility and degree of substitution(D.S) of pine were 81.4~95.9 % and 0.71~0.79, and those of oak were 76.2~89.5 % and 0.79~1.05. The values were higher than non-treated. The degree of substitution of purified carboxymethylated wood prepared with delignified EXM, pine and oak were 0.50~0.71 and 0.70~0.88. The color of carboxymethylated wood was white. In carboxymethylated wood preparde after delignification of EXM, swelling ratio and water retention value of pine were 95.9~96.5 and 580.0~751.2, those of oak were 76.2~89.5 and 124.3~307.6.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.1992-1996
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• 2007

This study focuses on the hydrogen embrittlement of iron tube for fuel line of PEMFC (Proton Exchange Membrane Fuel Cell). PEMFC is operated by feed of hydrogen as a reactant and steam for proton conductivity of membrane. However, the environment with hydrogen and steam occur the hydrogen-induced degradation in BOP system. When iron tube was exposed to hydrogen and steam condition for 24 hours, the oxide layer on the surface was decreased by reduction. When the ambient temperature was 90$^{\circ}C$ micro cracks were found on the surface than any other temperature. The mechanical strength of iron tube was 3% lower than that of non-experiment tube. Maximum tensile stress was decreased 8%.

• Journal of Magnetics
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• 제16권2호
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• pp.88-91
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• 2011

Steam generator tubes (SGTs) in nuclear power plants (NPPs) are a boundary between the primary side generating heat by nuclear fission and the secondary side generating electric power by a turbine. The water inside the SGT is high temperature and high pressure. Therefore, defects and magnetic phases (MPs) are partly produced in non-magnetic SGT by high stresses and temperatures. This causes trouble regarding the safety of SGTs but it is difficult to detect the MP using the conventional eddy current technique (ECT). In particular, a circumferential defect (CD) and circumferential magnetic phase (CMP) cannot detected by ECT. Consequently, a new method is needed to detect CDs and CMPs in SGT. A new U-type yoke with two types of coils was designed and the reactance signal by the CMPs and CDs in the SGT material was simulated.