• Nuclear Engineering and Technology
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• v.32 no.6
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• pp.537-548
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• 2000

The requirement of ultra high reliability of the safety critical software can not be demonstrated by testing alone. The specification based on formal method is recommended for safety system software. But there exist various kinds of formal methods, and this variety of formal method is recognized as an obstacle to the wide use of formal method. In this paper six different formal method have been applied to the same part of the functional requirements that is calculation algorithm intensive. The specification results were compared against the criteria that is derived from the characteristics that good software requirements specifications should have and regulatory body recommends to have. The application experience shows that the critical characteristics should be defined first, then appropriate method has to be selected. In our case, the Software Cost Reduction method was recommended for internal condition or calculation algorithm checking, and statechart method is recommended for the external behavioral description.

• Korean Journal of Veterinary Research
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• v.61 no.3
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• pp.20.1-20.9
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• 2021

This study is to develop a new scoring system for rating Hazard analysis and critical control points prerequisite evaluation items for meat shops to provide a more objective and accurate evaluation of food safety compliance. The importance of each item was measured by looking at the hazard severity level and the rate of non-compliance associated with it. It was found that the new scoring system is more stringent and gives a clearer picture of compliance with the most critical safety standards, and therefore is expected to have a positive effect on the hygiene and safety of livestock products.

• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.19-29
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• 2021

This paper presents the validation of the MCS code for critical safety analysis with burnup credit for the spent fuel casks. The validation process in this work considers five critical benchmark problem sets, which consist of total 80 critical experiments having MOX fuels from the International Criticality Safety Benchmark Evaluation Project (ICSBEP). The similarity analysis with the use of sensitivity and uncertainty tool TSUNAMI in SCALE was used to determine the applicable benchmark experiments corresponding to each spent fuel cask model and then the Upper Safety Limits (USLs) except for the isotopic validation were evaluated following the guidance from NUREG/CR-6698. The validation process in this work was also performed with the MCNP6 for comparison with the results using MCS calculations. The results of this work showed the consistence between MCS and MCNP6 for the MOX fueled criticality benchmarks, thus proving the reliability of the MCS calculations.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.598-608
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• 2016

This study examined the relationships among patient safety competence, critical thinking disposition, problem-solving competence, and self-efficacy of clinical nurses to identify the factors influencing the patient safety competence. A convenience sample of 373 nurses working in 4 general hospitals in a Metropolitan area in Korea was selected. After obtaining IRB approval, data collection was done with a structured self-administered questionnaire from October 14th to November 4th, 2014. The data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient and multiple regression analysis using the SPSS WIN 21.0 program. The participants showed a moderate level of patient safety competence ($3.75{\pm}0.37$), of critical thinking disposition ($3.43{\pm}0.27$), of problem solving competence ($3.54{\pm}0.30$), and of self-efficacy ($3.58{\pm}0.47$). The patient safety competence of the participants showed a significant correlation with the critical thinking disposition (r=.493, p<.001), problem solving competence (r=.616, p<.001), and self-efficacy (r=.475, p<.001). The significant factors influencing the patient safety competence were problem solving competence (${\beta}=.403$, p<.001), self-efficacy (${\beta}=.156$, p=.005), critical thinking disposition (${\beta}=.130$, p=.018), and having the experience of reporting patient safety accidents (${\beta}=.137$, p=.002). The results suggest that educational programs to enhance the critical thinking disposition, problem-solving competence, and self-efficacy would develop the patient safety competence of clinical nurses. In addition, more effort should be placed into reinforcing the patient safety competence by activating the report of patient safety accidents.

• International Journal of Safety
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• v.3 no.1
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• pp.38-46
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• 2004

This paper introduces the software life-cycle V&V (verification and validation) tasks for the KNICS (Korea nuclear instrumentation and control system) project. The objectives of the V&V tasks are mainly to develop a programmable logic controller (PLC) for safety critical instrumentation and control (I&C) systems, and then to apply the PLC to developing the prototype of an engineered safety features-component control system (ESF-CCS) in nuclear power plants. As preparative works for the software V&V, various kinds of software plans and V&V task procedures have been developed according to the software life-cycle management. A number of software V&V tools have been adopted or developed to efficiently support the V&V tasks. The V&V techniques employed in this work include a checklist-based review and inspection, a requirement traceability analysis, formal verification, and life-cycle based software testing.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.178.1-178
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• 2001

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3241-3251
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• 2023

The potential for recriticality and sub-critical boron concentrations is analyzed during the relocation of the fuel rods in the assembly, which we call late phase of a severe accident, via coupling between MELCOR and whole-core Monte Carlo analyses by Serpent 2. The recriticality, initiated during the early phase, is found to maintain when the fuel assemblies containing intact fuel rods are submerged by the cooling water. It is also found that the effect of the negative reactivity insertion via remaining fission products in the fuel debris increases as the burnup increases. The sub-critical boron concentrations during the late phase are found to be 76~544 ppm lower than those during the early phase. Therefore, it can be concluded that the boron concentration that prevents recriticality not only during the early phase but also during the late phase is the sub-critical boron concentration during the early phase.

• Journal of Digital Convergence
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• v.16 no.12
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• pp.511-521
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• 2018

The purpose of this study was to investigate the effect of critical thinking, clinical decision making ability, patient safety knowledge and attitude ability to perform patient safety activities during clinical practice on nursing student's. Data were analyzed using t-tests and one-way ANOVA using the SPSS 21.0 program. As a result, the subjects' safety nursing activities was positively correlated critical thinking disposition(r=.278, p=.001), clinical decision making ability(r=.202, p=.014), patient safety attitude(r=.421, p<.001).The significant predictors of perform safety nursing activities were gender(${\beta}=.175$, p=.031), patient safety education(${\beta}=-2.266$, p=.025), critical thinking disposition(${\beta}=3.354$, p=.001), patient safety attitude(${\beta}=.368$, p<.001). These factors explained 31.5% of the variance(R2=.561, F=4.56 p<.001). It is necessary to establish a curriculum for critical thinking disposition, clinical decision making ability, and patient safety education in order to improve patient safety performance necessary for clinical practice education of nursing college students.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.138-145
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• 2019

With the application of digital technology to safety-critical infrastructures, cyber-attacks have emerged as one of the new dangerous threats. In safety-critical infrastructures such as a nuclear power plant (NPP), a cyber-attack could have serious consequences by initiating dangerous events or rendering important safety systems unavailable. Since a cyber-attack is conducted intentionally, numerous possible cases should be considered for developing a cyber security system, such as the attack paths, methods, and potential target systems. Therefore, prior to developing a risk-informed cyber security strategy, the importance of cyber-attacks and significant critical digital assets (CDAs) should be analyzed. In this work, an importance analysis method for cyber-attacks on an NPP was proposed using the probabilistic safety assessment (PSA) method. To develop an importance analysis framework for cyber-attacks, possible cyber-attacks were identified with failure modes, and a PSA model for cyber-attacks was developed. For case studies, the quantitative evaluations of cyber-attack scenarios were performed using the proposed method. By using quantitative importance of cyber-attacks and identifying significant CDAs that must be defended against cyber-attacks, it is possible to develop an efficient and reliable defense strategy against cyber-attacks on NPPs.

• Journal of Advanced Navigation Technology
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• v.21 no.1
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• pp.50-57
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• 2017

Recently, safety-critical aviation system development programs promoted domestically have been terminated in the middle stage or they have not been put to practical use at the final stage. The program failure may be caused by various factors, but this study focused on imperfect test and evaluation(T&E) procedures. In general, T&E process of a safety-critical system must be distributed throughout the entire life-cycle of the system, have a continuity in phases, and can be implemented in a variety of ways depending on the maturity of the system development and acquisition strategy. This paper aims to present a new strategy by analyzing the domestic and overseas T&E processes to reduce the risk of domestic safety-critical CNS/ATM system development program and increase the success rate of program. First, we discuss the verification and validation techniques for safety-critical systems, analyze the T&E procedures of advanced institutes and the domestic situation, and then compare the domestic and overseas T&E processes to complement the imperfect testing procedure.