• Structural Engineering and Mechanics
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• 제87권6호
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• pp.601-614
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• 2023

In this study, the uniaxial ratcheting effect of Z2CND18.12N austenitic stainless steel at room and elevated temperatures is firstly simulated based on the Ahmadzadeh-Varvani hardening rule (A-V model), which is embedded into the finite element software ABAQUS by writing the user material subroutine UMAT. The results show that the predicted results of A-V model are lower than the experimental data, and the A-V model is difficult to control ratcheting strain rate. In order to improve the predictive ability of the A-V model, the parameter γ2 of the A-V model is modified using the isotropic hardening criterion, and the extended A-V model is proposed. Comparing the predicted results of the above two models with the experimental data, it is shown that the prediction results of the extended A-V model are in good agreement with the experimental data.

• Journal of Korean Biological Nursing Science
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• 제21권1호
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• pp.46-53
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• 2019

Purpose: This study was conducted to identify the effects of organizational culture for the infection control and self-efficacy on compliance with standard precautions of emergency room nurses. Methods: This cross-sectional descriptive study was conducted from 1st July to 3rd August, 2017. The participants were 200 nurses working in emergency rooms. The data was collected using structured self-report questionnaires. Results: The average scores for the organizational culture for infection control, self-efficacy and compliance with standard precautions were 5.54, 3.65, and 4.31, respectively. The organizational culture for infection control (r = .59, p< .001) and self-efficacy (r= .28, p< .001) were found to have a positive, meaningful correlation with compliance with the standard precautions. Multiple regression analysis showed that compliance with standard precautions was significantly affected by the organizational culture for infection control (${\beta}=0.55$, p< .001) and self-efficacy (${\beta}=0.13$, p= .033). Conclusion: The results for this study indicate that the organizational culture for infection control and self-efficacy were highly influential factors affecting compliance with standard precautions of emergency room nurses. Therefore, in order to improve the nurses' use of the standard precautions, it was necessary to develop and evaluate a program that considers the environmental factors and self-efficacy.

• 대한인간공학회지
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• 제36권5호
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• pp.373-383
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• 2017

Objective: The aim of this study is to introduce an operator console design review system suitable for designing and evaluating consoles based on human factor guidelines for a digitalized main control room in an advanced nuclear power plant which has a requirement for anthropometric data usage. Background: The system interface of the main control room in a nuclear power plant has been getting digitalized and consists of various consoles with many information displays. Console operators often face human-computer interactive problems due to inappropriate console design stemming from the perceptual constraints of anthropometric data usage. Method: Computational models with a process of visual perception and variables of anthropometric data are used for designing and evaluating operator consoles suitable for human system interface guidelines, which are used in an advanced nuclear power plant. Results: From the computational model and simulation application, console dimensions and a designing test module, which would be used for designing suitable consoles with safety concerns in a nuclear power plant, have been introduced. Conclusion: This case study may influence employing a suitable design concept with various anthropometric data in many areas with safety concerns and may show a feasible solution to designing and evaluating the safety console dimensions. Application: The results of this study may be used for designing a control room with the human factors requiring a safe working environment.

• 대한간호학회지
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• 제41권1호
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• pp.36-46
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• 2011

practice in operating room nursing and to examine the learning effects. Methods: Based on content and need analysis, 9 learning modules were developed for nursing care in operating rooms and with operating equipment. To verify the effects of the program, a quasi- experimental pretest-posttest control group design was employed. The participants in this study were 74 third-year nursing students (34 in the experimental and 40 in the control group) from a junior college in G-city, Korea, who were engaged in a one week clinical practicum in an operating unit. Frequencies, $X^2$-test and t-test with the SPSS program 17.0 were used to analyze the data. Results: Knowledge was significantly higher in the experimental group compared to the control group (p=.018). However, there was no significant difference between the two groups in self-directed learning. The experimental group had significantly higher motivation toward learning, which was examined posttest only (p=.027). Conclusion: These results indicate that the implementation of an e-Learning program needs to be continued as an effective educational tool, but more research on the best way to implement e-Learning in students' practicum is needed.

• 한국생산제조학회지
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• 제21권3호
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• pp.516-524
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• 2012

Selective Laser Sintering(SLS) system consists of various element technologies. Main components of the system include a position control system, a speed control system of the roller, and nitrogen atmosphere furtherance for the powdered sintering. Other systems which make the core of the SLS system are build room and the feed room for powder epitaxial, a temperature control system, and a scan path generator for the laser. The powder material for laser sintering is necessary to produce prototypes in Solid Freeform Fabrication(SFF) based on SLS process. This powder material is sintered in powder room using $CO_2$ laser after spreading evenly using roller to reproduce mold via SFF. This study addresses an SFF system by using the SLS process which applies single laser system to enable manufacturing of 3D shape. And to evaluate applicability of the single laser system, experiments were conducted with optimal fabricating process.

• 컴퓨터교육학회논문지
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• 제3권1호
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• pp.109-115
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• 2000

이 논문에서는 SNMP를 이용하여 윈도우 환경에서 동작하는 실습실의 PC를 관리하기 위해 MIB을 정의하고 이를 모니터링 및 제어하는 관리 시스템을 설계하였다. 제안된 시스템은 PC의 상태를 제어하는 제어 시스템과 실시간 모니터링 및 프로세스 제어를 담당하는 모니터링 시스템으로 구성된다. 제어 시스템의 경우 PC의 구성 정보 갱신 및 설정과 장애 발생시 이를 백업/복구를 담당한다. 모니터링 시스템은 초중고 생의 PC를 모니터링하고 실시간으로 실행중인 프로세스를 제어 및 새로운 작업을 실행시키는 기능을 갖고 있다. 이 시스템은 교사가 초중고의 PC 실습실에서 교육중 발생할 수 있는 학생들의 프로그램 사용을 통제하고 모니터링함으로써 교육의 효과를 높일 수 있다.

• 한국안전학회지
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• 제29권3호
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• pp.129-135
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• 2014

The number of abnormal operation procedures (AOPs) for mitigating a plant abnormal status amounts to about one hundreds for the most of 1000MWe optimized power plant (OPR1000) and it is expected that the number of AOPs would be increased to cope with an abnormal status occurred newly. However, it is not well organized for operators to select a proper AOP from alarms occurred in main control room (MCR) during a plant abnormal status. It may be a burden to operators since the selection of AOP to respond an abnormal status is authorized by operators. When multiple alarms occur in MCR, it would take more time to respond them than a single alarm. To reduce the efforts, various MCR operation support systems have been developed. The purpose of this study was to develop a multi-alarm pattern card to select an appropriate AOP effectively when multiple alarms occurs in a single upper layout (UL) of MCR. It can be applied for an operation support tool as well as an education tool.

• 대한안전경영과학회지
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• 제16권2호
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• pp.167-174
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• 2014

Heating and air conditioning system is changing rapidly from the traditional HVAC central supply system to the individual supply system with electrical heat pump system (EHP) in Korean school buildings. The individual supply system has advantages to turn on and off individually and to adjust the thermal comfort separately, but energy is wasted in the unoccupied classroom when the last leaving occupant does not turn off the controller. If the controller is to be off automatically while the classroom is not in use, energy consumption would decrease dramatically. This project aims to cease the unnecessary EHP supply in vacant classroom by inputting the class schedule from the central control room to reduce the energy-spending. Experimental measurements were carried out between the controlled classroom that is turned off when not in use and the uncontrolled room that is turned on continually. Occupant's comfort and energy consumption were measured and compared between the controlled case and the uncontrolled case. The energy consumption of controlled classroom case is 30-60% less than that of the uncontrolled classroom case. This result shows that controlling the cooling supply for the unoccupied classroom using the class schedule can decrease the energy consumption remarkably. This supply control system can be used to conserve energy in school structures like universities.

• 한국안전학회지
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• 제29권4호
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• pp.199-207
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• 2014

In this paper, to systematically assess the abandonment risk of main control room (MCR) fire, fire simulations with Fire Dynamics Simulator were performed and abandonment probabilities were estimated for the MCR bench-board fire of domestic reference nuclear power plant. The fire simulation scenarios performed in this study included propagating and non-propagating fires of the MCR bench-board, and the availability and unavailability of heating, ventilation, and air conditioning system (HVACS). The following results were obtained. First, temperature was the major abandonment impact factor for the MCR bench-board fire if the HVACS was available and optical density was that if the HVACS was unavailable. Second, the fire scenario contributing the MCR bench-board fire abandonment risk was identified to be only the propagating fire. Third, it was confirmed that the abandonment probability of the MCR bench-board fire for domestic reference nuclear power plant could be reduced by using the fire modeling.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.466-473
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• 2021

Fire protection is one of important issues to ensure safety and reduce risks of nuclear power plants (NPPs). While robust programs to shut down commercial reactors in any fires have been successfully maintained, the concept and associated regulatory requirements are constantly changing or strengthening by lessons learned from operating experiences and information all over the world. As part of this context, it is necessary not only to establish specific fire hazard assessment methods reflecting the characteristics of research reactors and educational reactors but also to make decisions based on advancement encompassing numerical analyses and experiments. The objectives of this study are to address fire simulation in the control room of an educational reactor and to discuss integrity of digital console in charge of main operation as well as analysis results through comparison. Three electrical fire scenarios were postulated and twenty-four thermal analyses were carried out taking into account two turbulence models, two cable materials and two ventilation conditions. Twelve supplementary thermal analyses and six subsequent structural analyses were also conducted for further examination on the temperature and heat flux of cable and von Mises stress of digital console, respectively. As consequences, effects of each parameter were quantified in detail and future applicability was briefly discussed. On the whole, higher profiles were obtained when Deardorff turbulence model was employed or polyvinyl chloride material and larger ventilation condition were considered. All the maximum values considered in this study met the allowable criteria so that safety action seems available by sustained integrity of the cable linked to digital console within operators' reaction time of 300 s.