• Journal of the Korean Institute of Gas
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• v.2 no.3
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• pp.12-17
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• 1998

Fault tree construction for hazard assessment requires so much time and labor, so it is very difficult to be applied to the large scale chemical plant. For the synthesis of fault tree in chemical processes, this study represents the cause-effect relations between process variables by using the Signed Directed Graph(SDG), and has synthesized Fault Tree(FT) by searching the causes of fault events using the general operator and loop operators defined corresponding to path characteristics on the SDG.

• Nuclear Engineering and Technology
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• v.39 no.1
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• pp.51-62
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• 2007

To efficiently design safety-critical systems such as nuclear power plants, with the requirement of high reliability, methodologies allowing for rigorous interactions between the synthesis and analysis processes have been proposed. This paper attempts to develop a reliability-centered design framework through an interactive process between Axiomatic Design (AD) and Fault Tree Analysis (FTA). Integrating AD and FTA into a single framework appears to be a viable solution, as they compliment each other with their unique advantages. AD provides a systematic synthesis tool while FTA is commonly used as a safety analysis tool. These methodologies build a design process that is less subjective, and they enable designers to develop insights that lead to solutions with improved reliability. Due to the nature of the two methodologies, the information involved in each process is complementary: a success tree versus a fault tree. Thus, at each step a system using AD is synthesized, and its reliability is then quantified using the FT derived from the AD synthesis process. The converted FT provides an opportunity to examine the completeness of the outcome from the synthesis process. This study presents an example of the design of a Containment Heat Removal System (CHRS). A case study illustrates the process of designing the CHRS with an interactive design framework focusing on the conversion of the AD process to FTA.

• Journal of the Korean Institute of Gas
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• v.5 no.2 s.14
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• pp.1-8
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• 2001

Fault tree construction for hazard assessment requires so much time and labor, so it is very difficult to be applied to the large scale chemical plant. In this study, for the synthesis of fault tree in chemical processes, the object-oriented knowledge framework is proposed to represent the deviations of process variables in the equipment and cause-consequence relationship with equipment faults. The cause of fault is searched by using the object-oriented modeling of equipments and the connectivity among equipments, and then a fault tree is synthesized. we have discussed the performance of the methodology on nitric acid cooling process to evaluate its effectiveness.

• Journal of KIISE:Software and Applications
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• v.32 no.12
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• pp.1178-1191
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• 2005

In this paper, we propose a synthesis method of software fault tree from software requirements specification written in NuSCR formal specification language. The software fault tree, proposed in this paper, reflects requirements on both structure and behavior and it is an integrated form. The software fault tree can be used for analyzing safety in the view of structure and behavior. We propose templates for each components in NuSCR specification language and a synthesis method of software fault tree using the templates. The research was applied into the main trip logic of the reactor protection system of ARP1400, the Korean next generation nuclear reactor system, developed by KNICS. And we evaluate feasibility of our approach through this case study.

• 한국가스학회:학술대회논문집
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• 1998.09a
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• pp.41-46
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• 1998

• Nuclear Engineering and Technology
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• v.40 no.5
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• pp.365-374
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• 2008

Dependability-critical systems, such as digital instrumentation and control systems in nuclear power plants, necessitate engineering techniques and tools to provide assurances of their safety and reliability. Determining system reliability at the architectural design phase is important since it may guide design decisions and provide crucial information for trade-off analysis and estimating system cost. Despite this, reliability and system engineering remain separate disciplines and engineering processes by which the dependability analysis results may not represent the designed system. In this article we provide an overview and application of our approach to build architecture-based, dynamic system models for dependability-critical systems and then automatically generate dynamic fault trees (DFT) for comprehensive, tool-supported reliability analysis. Specifically, we use the Architectural Analysis and Design Language (AADL) to model the structural, behavioral and failure aspects of the system in a composite architecture model. From the AADL model, we seek to derive the DFT(s) and use Galileo's automated reliability analyses to estimate system reliability. This approach alleviates the dependability engineering - systems engineering knowledge expertise gap, integrates the dependability and system engineering design and development processes and enables a more formal, automated and consistent DFT construction. We illustrate this work using an example based on a dynamic digital feed-water control system for a nuclear reactor.