• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.283-290
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• 1999

Recently, the ${\mu}$-processor based-controlled systems instead of conventional relays circuitry are widely used to industrial applications, and also those technology is available to railway signalings which are safety-critical systems. However, the safety and reliability of software for those systems are harder to demonstrate than in traditional relays circuitry because the faults or errors can not be analyzed and predicted to those systems. So, the safety problems are crucial more and more in ${\mu}$-processor based-controlled system. In this paper, the Grafcet language, the graphical and mathematical form, is used to obtain the high-level safety and reliability of software control logic. The general description for Grafcet notation are provided. And some partial of interlocking logic are formally modeled and simulated by Grafcet language and graphical windows.

• Journal of Radiation Protection and Research
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• 제49권1호
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• pp.40-49
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• 2024

Background: This study aimed to prioritize policy measures to improve radiation safety management in medical institutions using the analytic hierarchy process. Materials and Methods: It adopted three policy options-engineering, education, and enforcement-to categorize safety management measures, the so-called Harvey's 3Es. Then, the radiation safety management measures obtained from the current system and other studies were organized into action plan categories. Using the derived model, this study surveyed 33 stakeholders of radiation safety management in medical institutions and analyzed the importance of each measure. Results and Discussion: As a result, these stakeholders generally identified enforcement as the most important factor for improving the safety management system. The study also found that radiation safety officers and medical physicists perceived different measures as important, indicating clear differences in opinions among stakeholders, especially in improving quality assurance in radiation therapy. Hence, the process of coordination and consensus is likely to be critical in improving the radiation safety management system. Conclusion: Stakeholders in the medical field consider enforcement as the most critical factor in improving their safety management systems. Specifically, the most crucial among the six specific action plans was the "reinforcement of the organization and workforce for safety management," with a relative importance of 25.7%.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(2)
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• pp.631-636
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• 1996

This paper presents a Reliability Centered Maintenance (RCM) framework for implementation on safety system of nuclear power plant (NPP). RCM is a systematic methodology to optimize the surveillance and maintenance tasks for critical components which provides efficiently and effectively reliability of system and safety of plant. Maintenance of the safety systems is essential for its safe and reliable operation. Reliability Centered Maintenance at NPP is the program which assure that plant system remains within original design criteria and that is not adversely affected during the plant life time. Aim of this paper is to provide the RCM framework to implement it on safety systems. RCM framework is described in four major steps.

• 시스템엔지니어링학술지
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• 제17권2호
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• pp.114-121
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• 2021

Today, it is a time when self-help efforts are being made to increase the demand for international certification by domestic and foreign railway orderers and develop excellent railway systems for railway system and railway construction projects. Since 2011, cases of obtaining international certification related to the domestic railway system/products have been collected and analyzed through literature and Internet data and based on the analysis results, evaluation results on the acquisition of international certification in Korea are presented. Through these results, the government, research institutes, and industries will be practical reference materials for international certification-related work.

• 시스템엔지니어링학술지
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• 제12권2호
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• pp.81-90
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• 2016

The system performance of Engineered Safety Features is of utmost importance in a nuclear power plant. The human performance is identified as most critical to assurance of the optimal operability of safety systems during an emergency. The aim of this study is to determine how the performance of safety system could be evaluated using Augmented Reality technology. The paper presents a description of how a systems engineered approach could be used to develop the necessary operating conditions needed to conduct this measurement. Augmented Virtual Reality (AVR) interface technology is achieving ease of availability and widespread use in many applications today as illustrated by the launch of several AR and VR devices aimed at media consumption. As such, environments that incorporate such AVR hardware have become invaluable tools in designing human interface systems because of the high fidelity and intuitive response to natural human interaction that can be achieved [2]. The outcome of the measurement undertaken is to determine whether 1.) Operator(s) performance can be enhanced by introducing an improved cognitive method of monitoring plant information during an Emergency Operating Procedures (EOP) and 2.) In correlation, inform the performance of the diverse safety systems on the basis of human factors.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1995년도 춘계학술대회논문집
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• pp.111-114
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• 1995

As modern industrial technologies progress, critical incidents (both conventional and new) occur as well. Although majority of these safety incidents are human-related, or human factors problems, industrial systems and/or occupational safety operations are often designed without seriously considering important roles of human factors in industrial safety. The purpose of this paper is to show how a human factors approach can contribute to industrial safety. The paper introduces a systems safety concept with some useful analysis techniques for proactively preventing human-related safety problems. A behavior-based safety analysis approach to modify hyman behavior is suggested to reduce unsafe behavior and promote safe behavior. Finally, a sound human factors/ergonomics program is recommended for management to establish a hazard-free work environment. Some current and future research issues are discussed.

• International journal of advanced smart convergence
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• 제11권3호
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• pp.56-63
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• 2022

Cyber-physical systems (CPSs) can solve real problems by utilizing closely connected resources in the cyber world. Most problems arise because the physical world is uncertain and unpredictable. To address this uncertainty, information pouring from numerous devices must be collected in real-time, and each interconnected device must share the information. At this time, CPS must meet timing-related techniques and strict timing constraints that can deliver accurate information within predefined deadlines in order to interact closely beyond simply connecting the cyber and physical worlds. Timing errors in safety-critical systems, such as automobiles, aviation, and medical systems, can lead to catastrophic disasters. In this paper, we classify timing problems into two types: real-time delay and synchronization problems. The results of this study can be used in the entire process of CPS system design, implementation, operation, verification, and maintenance. As a result, it can contribute to securing the safety and reliability of CPS.

• Nuclear Engineering and Technology
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• 제52권7호
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• pp.1462-1470
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• 2020

Reliability in safety-critical systems and equipment is of vital importance, so the probabilistic safety assessment (PSA) has been widely used for many years in the nuclear industry to address reliability in a quantitative manner. As many nuclear power plants (NPPs) become digitalized, evaluating the reliability of safety-critical software has become an emerging issue. Due to a lack of available methods, in many conventional PSA models only hardware reliability is addressed with the assumption that software reliability is perfect or very high compared to hardware reliability. This study focused on developing a new method of safety-critical software reliability quantification, derived from hardware-software integrated environment testing. Since the complexity of hardware and software interaction makes the possible number of test cases for exhaustive testing well beyond a practically achievable range, an importance-oriented testing method that assures the most efficient test coverage was developed. Application to the test of an actual NPP reactor protection system demonstrated the applicability of the developed method and provided insight into complex software-based system reliability.

• International Journal of Computer Science & Network Security
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• 제23권12호
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• pp.1-12
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• 2023

Ensuring the security of Supervisory Control and Data Acquisition (SCADA) and Industrial Control Systems (ICS) is paramount to safeguarding the reliability and safety of critical infrastructure. This paper addresses the significant threat posed by reconnaissance attacks on SCADA/ICS networks and presents an innovative methodology for enhancing their protection. The proposed approach strategically employs imbalance dataset handling techniques, ensemble methods, and feature engineering to enhance the resilience of SCADA/ICS systems. Experimentation and analysis demonstrate the compelling efficacy of our strategy, as evidenced by excellent model performance characterized by good precision, recall, and a commendably low false negative (FN). The practical utility of our approach is underscored through the evaluation of real-world SCADA/ICS datasets, showcasing superior performance compared to existing methods in a comparative analysis. Moreover, the integration of feature augmentation is revealed to significantly enhance detection capabilities. This research contributes to advancing the security posture of SCADA/ICS environments, addressing a critical imperative in the face of evolving cyber threats.

• Journal of Electrical Engineering and Technology
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• 제1권4호
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• pp.513-519
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• 2006

As a very important part in development of the protocol, verifications for developed protocol specification are complementary techniques that are used to increase the level of confidence in the system functions by their specifications. Using the informal method for specifying the protocol, some ambiguity may be contained therein. This indwelling ambiguity in control systems can cause the occurrence of accidents, especially in the case of safety-critical systems. To clear the vagueness contained in the designed protocol, we use the LTS (Labeled Transition System) model to design the protocol for railway signaling. And then, we verify the safety and the liveness properties formally through the model checking method. The modal ${\mu}$-calculus, which is an expressive method of temporal logic, has been applied to the model checking method. We verify the safety and liveness properties of Korean standard protocol for railway signaling systems. To perform automatic verification of the safety and liveness properties of the designed protocol, a communication verification tool is implemented. The developed tools are implemented by C++ language under Windows XP. It is expected to increase the safety and reliability of communication protocol for signaling systems by using the developed communication verification tool.