• Proceedings of the Safety Management and Science Conference
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• 2006.04a
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• pp.237-249
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• 2006

Critical incident can be happened at any time, any places without any pre-notification. For minimizing the loss of the life safety, financial and so on caused by the risk, most of company needs a system what can activate the critical incident management plan to prevent, plan for and respond to events that become critical incident. But a lot of company still don't have such a detailed system in our country and almost company has no effective training way for to boot. This paper shows the way to activate the risk management system to work efficiently the plan. The training way, proposed by this paper, is a incident command simulator based on virtual reality and scenario generation software.

• Journal of the Korea Safety Management & Science
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• v.8 no.4
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• pp.25-37
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• 2006

Critical incident can be happened at any time, any places without any pre-notification. For minimizing the loss of the life safety, financial and so on caused by the risk, most of company needs a system what can activate the critical incident management plan to prevent, plan for and respond to events that become critical incident. But a lot of company still don't have such a detailed system in our country and almost company has no effective training way for to boot. This paper shows the way to activate the risk management system to work efficiently the plan. The training way, proposed by this paper, is a incident command simulator based on virtual reality and scenario generation software.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.05a
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• pp.226-226
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• 2004

• Proceedings of the KSR Conference
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• 1999.05a
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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 Institute of Control, Robotics and Systems
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• v.12 no.11
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• pp.1130-1137
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• 2006

Relaxed Static Stability(RSS) concept has been applied to improve aerodynamic performance of modern version supersonic jet fighter aircraft. Therefore, the flight control systems are necessary to stabilizes the unstable aircraft and provides adequate handling qualities. The initial production flight control system are verified by flight test and it's always an elements of danger because of flight-critical nature of control law function and design error due to model base design method. These critical issues impact to flight safety, and it could be lead to a loss of aircraft and pilot's life. Therefore, development of an easily modifiable RFCS(Research Flight Control System) capable of reverting to a PFCS(Primary Flight Control System) of reliable control law must be developed to guarantee the flight safety. This paper addresses the concept of SSWM(Software Switching Mechanism) using the fader logic such as TFS(Transient Free Switch) based on T-50 flight control law. The result of the analysis based on non-real time simulation in-house software using SSWM reveals that the flight control system are switching between two computers without any problem.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.153-158
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• 1997

This paper describes a formal safety analysis technique which is demonstrated by performing empirical formal safety analysis with the case study of beamline hutch door Interlock system that is developed by using PLC(Programmable Logic Controller) systems at the Pohang Accelerator Laboratory. In order to perform formal safety analysis, we have built the Z formal specifications representation from user requirement written in ambiguous natural language and target PLC ladder logic, respectively. We have also studied the effective method to express typical PLC timer component by using specific Z formal notation which is supported by temporal history. We present a formal proof technique specifying and verifying that the hazardous states are not introduced into ladder logic in the PLC-based safety critical system.

• KIISE Transactions on Computing Practices
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• v.23 no.6
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• pp.335-342
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• 2017

In the verification and validation procedures regarding the safety-critical software of nuclear power plants for the attainment of the requisite license from the regulatory body, it is difficult to judge the safety and dependability of the development, implementation, and validation activities through a simple reading and review of the documentation. Therefore, these activities, especially safety assurance activities, require systematic evaluation techniques to determine that software faults are acceptable level. In this study, a safety case methodology is applied in an assessment of the level and depth of the results of the development and validation of a manufacturer in its targeting of the bistable processor of a digital reactor protection system, and the evaluation results are analyzed. This study confirms the possibility of an effective supplementation of the existing safety demonstration method through the application of the employed safety case methodology.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1467-1473
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• 2004

It requires different safety programs from those of the typical train control systems to develop AGT systems applying train control system based on communication technology. Especially Advanced LRT system involves the processes that have the various safety functions being conducted by softwares and also have characteristics that should have special interest in validation of interface specification. The core items for the safety engineering for LRT control systems are hardware & software engineering, safety-critical system safety engineering, application software validation & verification technologies. In this paper the trends of the technologies for the mentioned core-items are described.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3885-3892
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• 2010

Safety-Critical systems, such as Plant Protection Systems in nuclear power plant, plays a key role that the facilities can be operated without undue risk to the health and safety of public and environment, and those systems shall be designed, fabricated, installed, and tested to quality standards commensurate with the importance of the functions to be performed. Computer-based Instrumentation and Control Systems to perform the safety-critical function have Real Time Operating Systems to control and monitoring the sub-system and executing the application software. The safety-critical Real Time Operating Systems shall be designed, analyzed, tested and evaluated to have capability to maintain a high integrity and quality. However, local nuclear power plants have applied the real time operating systems on safety critical systems through Commercial Grade Item Dedication method, and this is the reason of lack of detailed methodology on assessing the safety of real time operating systems, expecially to the new developed one. This paper presents the methodology and experiences of safety evaluation on safety-critical Real Time Operating Systems based upon design requirements. This paper may useful to develop and evaluate the safety-critical Real Time Operating Systems in other industry to ensure the safety of public and environment.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.1
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• pp.1-8
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• 2015

Safety critical systems require exhaustive verification of safety properties, because even a single corner-case fault can cause a critical safety failure. However, existing verification approaches are too costly in terms of time and computational resource required, making it hard to be applied in practice. In this paper, we implemented a tool for minimizing the size of the verification target w.r.t. verification properties to check, based on program slicing technique[1]. The efficacy of program slicing using our tool is demonstrated in a case study with a verification target Trampoline[3], which is an open source automotive operating system compliant with OSEK/VDX[2]. Experiments have shown enhanced performance in verification, with a 71% reduction in the size of the code.