• Communications of the Korean Institute of Information Scientists and Engineers
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• v.31 no.5
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• pp.46-55
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• 2013

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.88-90
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• 2001

원자력 발전소 내장형 시스템은 안정성과 신뢰성이 절대적으로 요구되는 Safety-critical 시스템이다. 이러한 시스템의 설계는 모호성이 없는 정형명세 언어로 설계함으로 설계자와 구현자 사이의 모호성 없는 의사전달을 달성할 수 있다. 이러한 특히 원자력 발전소 내장형 시스템의 설계에 있어서 설계자는 그가 설계한 설계를 시험(Validation)하고 검증(Verification)하는 기법을 필요로 하게 된다. 특히 시스템이 복잡해질수록 설계도 내의 오류를 발견하지 못할 가능성이 커진다. 본 논문에서는 시스템이 가질 수 있는 모든 상태를 만들어내어 검사하는 형태의 검증 기법인 정형기법을 통하여 Safety-critical 한 내장형 시스템의 설계를 검증함으로 보다 완벽한 시스템을 설계하는 기법을 제안한다.

• Journal of the Korea Safety Management & Science
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• v.19 no.4
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• pp.291-299
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• 2017

Recently, many business and government organizations have benefitted by executing projects using TOC-CCPM(Theory of Constraints-Critical Chain Project Management). In parallel, Earned Value Management(EVM) metrics have also become popular. Many organizations like US government requires that all large projects measure and report project progress status using EVM. Thus, project management in business fields such as plant construction, IT development, ship building need to integrate TOC-CCPM and EVM in oder to keep and reduce the delivery date of projects for improvement of customer satisfaction and enlargement of business opportunity. This paper proposes the scheme and case of developing the Synchro-EVM system which TOC-CCPM and EVM are connected.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.69-83
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• 2009

According to the accident statistics of 2006, it can be recognized that drivers' characteristics and driving behaviors are the most causational factors on the traffic accidents. At present, many recording tools such as digital speedometer or black box are distributed in the market to meet social requests of decreasing traffic accidents and increasing safe driving behaviors. However, it is also true that the system preventing any possible vehicle accidents in advance has not been developed. In this study, we developed critical value for deciding dangerous driving behaviors. The developed critical value could be used to contribute to safety driving management systematization and safety driving behaviors.

• Journal of the Korean Society for Railway
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• v.8 no.2
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• pp.170-175
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• 2005

This study presents a prediction of a failure rate in a safety required system that consists of a embedded control system, requiring a satisfaction of a quantitative safety requirement. International Standards are employed to achieve a regular procedures in the whole life cycle of a system, for the purpose of a prediction and a evaluation of a fault that might be able to be happened in a system. This International Standards uses SIL (Safety Integrity Level) to evaluate a safety level of a system. SIL is divided into 4 levels, from level 1 to level 4, and each level has functional failure rate and dangerous failure rate of a system. In this paper we describe the conventional method to predict the dangerous failure rate and propose a method using hazard analysis to predict the dangerous failure rate. The conventional method and the technique using hazard analysis to predict the dangerous failure rate are made a comparison through the control modules of the interlocking system in KTX. The proposed method verify better effectiveness for the prediction of the dangerous failure rate than that of the conventional method.

• Journal of the Korean Society for Railway
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• v.11 no.1
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• pp.101-106
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• 2008

Recently, Architecture Frameworks are used to develop Information Management System (IMS). This paper describes an operational architecture development method for railway system safety assessment. using DoDAF (Department of Defense Architecture framework). The need of IMS is increasing to perform safety assessment task effectively and efficiently as safety-critical system like railway System. It is necessary that operational architecture based IMS requirements generated fir safety assessment. ARP(Aerospace Recommended Practice)4761 are referred to develop safety assessment operational architecture applicable to railway system. Firstly, schema and template was developed to perform the operational architecture development process using a commercial CASysE(Computer-Aided Systems engineering) tool, CORE. Not only the operational architecture allows building flexible IMS, but also helps business process solving.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3694-3703
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• 2021

Instrumentation and Control systems (I&C) play a significant role in nuclear power plants (NPP) and other safety critical systems (SCS). We have conducted a rigorous study and discussions with experienced practitioners worldwide the strategy for the development of I&C systems to investigate the several aspects related to their dependability. We discussed with experienced practitioners that work on nuclear domain with the intention of knowing their approach, they use day-to-day for the development of such systems. The aim of this research is to obtain to provide guidance to those building I&C systems of NPP and have implications on state engineering licensure boards, in the determination of legal liability, and in risk assessment for policymakers, corporate governors, and insurance executives.

• Nuclear Engineering and Technology
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• v.45 no.2
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• pp.237-248
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• 2013

Thermal stratification has continuously caused several piping failures in nuclear power plants since the early 1980s. However, this critical thermal effect was not considered when the old nuclear power plants were designed. Therefore, it is urgent to evaluate this unexpected thermal effect on the structural integrity of piping systems. In this paper, the thermal effects of stratified flow in two different safety injection piping systems were investigated by using a coupled CFD-FE method. Since stratified flow is generally generated by turbulent penetration and/or valve leakage, thermal stress analyses as well as CFD analyses were carried out considering these two primary causes. Numerical results show that the most critical factor governing thermal stratification is valve leakage and that temperature distribution significantly changes according to the leakage path. In particular, in-leakage has a high possibility of causing considerable structural problems in RCS piping.

• 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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• 2002.10a
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• pp.117.2-117
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• 2002