• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.764-775
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• 2020

Periodic safety reviews (PSRs) are conducted on operating nuclear power plants (NPPs) and have been mandated also for research reactors in Korea, in response to the Fukushima accident. One safety review tool, the probabilistic safety assessment (PSA), aims to identify weaknesses in the design and operation of the research reactor, and to evaluate and compare possible safety improvements. However, the PSA for research reactors is difficult due to scarce data availability. An important element in the analysis of research reactors is the reactor protection system (RPS), with its functionality and importance. In this view, we consider that of the AGN-201K, a zero-power reactor without forced decay heat removal systems, to demonstrate a risk-informed safety improvement study. By incorporating risk- and safety-significance importance measures, and sensitivity and uncertainty analyses, the proposed method identifies critical components in the RPS reliability model, systematically proposes potential safety improvements and ranks them to assist in the decision-making process.

• Journal of Korean society of Dental Hygiene
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• v.16 no.1
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• pp.85-92
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• 2016

Objectives: The purpose of this study was to investigate comparison of the effectiveness on knowledge improvement before and after the oral health education focusing on foreign students. Methods: A self-reported questionnaire was filled out by 40 foreign students in Sun Moon University from June 2 to September 30, 2014. The experimental group had an online oral health education and the control group had an off line education. The questionnaire consisted of oral health(10 items), toothbrushing(10 items), dental caries(10 items), periodontal disease(5 items), tooth sensitivity(5 items), oral cancer(6 items), and smoking(5 items). The data were analyzed by SPSS Win 18.0 program. Results: Knowledge scores of online education increased to average 1.257 points, and that of offline education was average of 2.56 points. There were statistically significant results for toothbrushing, dental caries, periodontal disease, tooth sensitivity, oral cancer and TMD except for smoking in offline education group. Conclusions: This study suggests that the offline oral health education is more effective than online oral health education.

• Advances in environmental research
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• v.1 no.2
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• pp.125-142
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• 2012

Clean development mechanism (CDM) validity study was conducted to suggest better and more adaptable CDM scenario on water treatment plant (WTP). Potential four scenarios for CDM project; improvement of intake pumping efficiency, hydro power plant construction, solar panel construction and system optimization of mechanical mixing process were evaluated on S-WTP in Korea. Net present value (NPV) of each scenario was estimated based on sensitivity analysis with the variable factors to investigate the CDM validity percentile. Hydro power plant construction was the best option for CDM business with 97.76% validity and $1,127,069 mean profit by 9,813 $tonsCO_2e$/yr reduction. CDM validity on improvement of intake pumping efficiency was 90.2% with $124,305 mean profit by huge amount of $CO_2$ mitigation (10,347 $tonsCO_2e$/yr). System optimization of mechanical mixing process reduced 15% of energy consumption (3,184 $tonsCO_2e$/yr) and its CDM validity and mean profit was 77.25% and $23,942, respectively. Solar panel construction could make the effect of 14,094 $tonsCO_2$ mitigation annually and its CDM validity and mean profit was 64.68% and $228,487, respectively.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.2
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• pp.82-87
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• 2017

This paper presents performance improvement of CO gas sensor signal conditioner for early fire warning system. The warning system is based on the CO sensor and its advanced signal conditioning modules network that employ electochemical gas sensor. The electochemical has advantage of having a linear output and operating with a low consumption and fast response. This electrochemical gas sensor contains a gas membrane and three electrodes(working, counter, reference electrode) in contact with an electrolyte. To use a three-electrode sensor, a voltage has to be applied between the working and the reference electrode according to the specification of the sensor. In this paper, we designed these requirements that should be considered in temperature compensation algorithm and electrode measurement of CO sensor modules by using advanced signal conditioning method included 3-electrode. Simulation and experimental results show that signal conditioner of CO sensor module using 3-electrode have a advantage linearity, sensitivity and stability, fast response etc..

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3265-3267
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• 1999

Capacitance-type alcohol gas sensors using porous silicon (PS) layer as sensitive film were fabricated to measure low alcohol gas concentration. Though sensors using porous silicon layer have show high sensitivity by large internal surface area, there is still much room for improvement to measure low breath alcohol concentration especially at room temperature. In this work, to discuss the response properties against exposure to organic vapor for breath alcohol measurements on the basis of experimental results. we measured the variation of the capacitance for the range of 0 to 0.5% alcohol concentration, and observed the improvement of sensitivity by illumination of UV light. In addition, the effect of CO2 and N2 gases involved commonly in exhaling breath was estimated, and the same procedure against methanol vapor was executed to compare qualitatively with the capacitance characteristics by alcohol vapor.

• Journal of Engineering Education Research
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• v.16 no.6
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• pp.58-64
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• 2013

We compared the cognitions of students, faculty, and business leaders in engineering related to woman employment and successful career. For this research, we developed questionnaires for 240 students of Korea National University of Transportation and Korea National University of Education, and 8 faculty who taught the students in the improvement program of engineering education environment for gender sensitivity, and 28 business leaders of company located in Chungbuk. As results, there were lots of difference among the cognitions of students, faculty, and the leaders related to woman employment and successful career. Especially, leaders gave considerable thought to upright character and affective capacity when they select employees. Therefore, we need to concentrate efforts to bring up talent women whom companies prefer by strengthening the strength and make up for the weakness as women in the improvement program of engineering education environment for gender sensitivity.

• Journal of Korean Academy of Nursing Administration
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• v.17 no.4
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• pp.484-492
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• 2011

Purpose: The aims of study were; (1) to evaluate the validity and sensitivity of a fall-risk assessment tool, and (2) to establish continuous quality improvement (CQI) methods to monitor the effective use of the risk assessment tool. Methods: A retrospective case-control cohort design was used. Analysis was conducted for 90 admissions as cases and 3,716 as controls during the 2006 and 2007 calendar years was conducted. Fallers were identified from the hospital’s Accident Reporting System, and non-fallers were selected by randomized selection. Accuracy estimates, sensitivity analysis and logistic regression were used. Results: At the lower cutoff score of one, sensitivity, specificity, and positive and negative predictive values were 82.2%, 19.3%, 0.03%, and 96.9%, respectively. The area under the ROC was 0.60 implying poor prediction. Logistic regression analysis showed that five out of nine constitutional items; age, history of falls, gait problems, and confusion were significantly associated with falls. Based on these results, we suggested a tailored falls CQI process with specific indexes. Conclusion: The fall-risk assessment tool was found to need considerable reviews for its validity and usage problems in practice. It is also necessary to develop protocols for use and identify strategies that reflect changes in patient conditions during hospital stay.

• Journal of Radiation Protection and Research
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• v.29 no.4
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• pp.257-261
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• 2004

A coded-aperture gamma camera was developed to increase the sensitivity of a pin hole camera made with a pixellated CsI(Tl) scintillator and a position-sensitive photomultiplier tube. The modified round-hole uniformly redundant array of pixel size $13{\times}11$ was chosen as a coded mask considering the detector spatial resolution. The performance of the coded-aperture camera was compared with the pin hole camera using various forms of Tc-99m source to see the improvement of signal-to-noise ratio or the improvement of the sensitivity. The image quality is much improved despite of a slight degradation of the spatial resolution. Though the camera and the test were made for low energy case, but the concept of the coded-aperture gamma camera could be effectively used for the radioactive environmental monitoring and other applications.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.244-244
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• 2017

Recently, A study is actively underway to apply to various industries, which are one of the major changes in the key drivers of the industry 4.0.. The data generated by the ship include various indicators such as the fuel volume, engine power, ground speed, speed, speed, main engine rpm, DFOC, SFOC, and FOC. This paper analyzes the sensitivity of the Gathering data and analyzes the impact energy efficiency of the vessel operation by analyzing the influence among each parameter, using the mathematical models, you create an surrogate model using the math model, comparative analysis of actual measurement data and predictive results were analyzed. Through the use of big data analysis technology, it is possible to identify the sensitivity between the energy efficiency related variables of the ship, The possibility of utilization of fuel efficiency indicators using of the surrogate model is identified.

• Journal of the Korean Society for Heat Treatment
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• v.24 no.2
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• pp.87-91
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• 2011

Single layer Sn doped $In_2O_3$ (ITO) films and ITO 50 nm / Au 10 nm / ITO 40 nm (IAI) multilayer films were prepared with electron beam assisted magnetron sputtering on glass substrates. The effects of the Au interlayer, post-deposition atmosphere annealing and intense electron irradiation on the methanol gas sensitivity were investigated at room temperature. As deposited ITO films did not show any diffraction peaks in the XRD pattern, while the IAI films showed the diffraction peak for $In_2O_3$ (400). In this study, the gas sensitivity of ITO and IAI films increased proportionally with the methanol vapor concentration and an intense electron beam irradiated IAI film shows the higher sensitivity than the others film. From the XRD pattern, it is supposed that increased crystallization promotes the gas sensitivity. This approach is promising in gaining improvement in the performance of IAI gas sensors used for the detection of methanol vapor at room temperature.