• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.12
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• pp.1905-1910
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• 2013

This paper demonstrates the result of Safety Integrity Level (SIL) allocation for IL-type Train Control System(IL-TCS), by applying the semi-quantitative approach. IL-type TCS is defined in this paper as the set of Hardware and Software ATS equipment, Track-side ATP equipment, On-board ATP equipment, Track-side ATO equipment, On-board ATO equipment. SIL allocation is performed for these constituent subsystems of TCS. Based on three principles of the semi-quantitative method, the SIL allocation process is performed for the subsystems composing TCS.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.3
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• pp.157-165
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• 2022

As the number of the installed escalators in Korea continues to increase, the accident rate is also increasing. Therefore, it would be necessary to proactively secure safety. PESSRAE is a controller that implements safety functions as electric/electronic/programmable electronic devices to respond to risks that may occur in escalators. Safety Integrity Level (SIL) is assigned to the safety functions of PESSRAE and it must be verified that the quantitative target value according to the SIL level is satisfied. In this paper, the initial PESSRAE is analyzed using the FMEDA (Failure Mode, Effects and Diagnostic Analysis), which is a quantitative safety analysis method, and design improvement specifications are derived from the analysis in order to satisfy the quantitative target values. Based on the derived design specifications, the improved PESSRAE controller was manufactured. And the appropriateness of the design was verified experimentally in a testbed environment simulating the real environment.

• Journal of the Korean Institute of Gas
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• v.6 no.1 s.17
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• pp.66-73
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• 2002

In this study a new SIS evaluation method based on the reliability analysis has been developed. It evaluates the Safety Integrity Level (SIL) using the Fault Tree Analysis (FTA), and when the SIL falls short of the systems target level, through the reliability analysis and system retrofit, this method will satisfy the aimed SIL. A hazard evaluation was carried out on the 415V Diesel BUS to verify the SIL evaluation method based on the reliability analysis. The availability of the original 415V Diesel BUS was $99.40\%$, which comes under the category of SIL 2. After exchanging the diesel generator and the isolator switch using the developed evaluation method, the availability rose to $99.94\%$, SIL 3. By applying the method presented in this study, not only will it reduce the maintenance cost due to the prevention of accidents and reduction of loss, but also maximize the reliability of the system.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.9
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• pp.1001-1008
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• 2015

This paper introduces the architecture of the power supply in order to achieve the safety integrity target for power supply which is a part of safety related system. The integrity level for safety is set 4 and according to the IEC 62425 which is standard for railway application the architecture design is conducted and process for design is developed. The procedure for design consists with 6 steps. The architecture of power supply that is able to keep the safety integrity against of failure of power supply is derived through the analysis and it is suggested that the power supply adopted the result in this paper is suitable to apply in safety system. Also, the failure frequency that is a quantitative value for the power supply is proposed.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2023.11a
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• pp.221-221
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• 2023

1969년에 발간된 API521 1st edition에서는 Flare Load 저감용으로 적용되는 HIPS (High Integrity Protection System)는 모두 Pressure Safety Valve의 고장확률보다 낮은 SIL 3 (Safety Integrity Level)등급을 적용할 것을 요구하고 있다. Flare Stack 저감용 HIPS는 주로 압축기 출력압력상승, Reboiler Steam 과다주입, 전력공급중단냉각펌프고장 등에 의한 Flare 발생을 예방하기 위한 기능을 가진 SIF (Safety Instrumented Function)로 구성된다. 하지만 2007년도 발간된 API521 5th edition에서는 LOPA (Layer Of Protection Analysis) 분석을 통해 Target SIL을 도출하는 것으로 요구사항을 변경했다. 이에 따라 이번 연구에서는 Flare Load에 가장 큰 영향을 미치는 시나리오 중 대표적인 시나리오를 대상으로 HAZOP(Hazard and Operability Study)과 LOPA분석을 실시해서 Target SIL이 어떻게 도출되는지를 연구했다. Flare Stack에서 Flare를 발생시키는 대표적인 시나리오들에 대해 LOPA분석을 실시한 결과 압축기 출력압력상승은 SIL 2, Reboiler Steam 과다주입은 SIL 3, 전력공급중단은 SIL 0, 냉각펌프고장은 SIL 0로 모두가 SIL 3 가 나오지는 않았다. SIF 설계 시 Target SIL을 만족시키는 것도 중요하지만 운전 시 SIL 등급이 계속 유지되게 하지 위해 인적오류, 시스템적 고장, 하드웨어고장 등에 의해 SIF 기능불능화가 되는 것을 예방하기 위한 기능안전관리시스템 (FSMS)를 적용하는 것도 중요하다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.1
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• pp.43-47
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• 2017

A SIL(Safety Integrity Level) assignment method is used for preventing failure action. The goal of safety system for processing automation is to reduce the human fatal risk. Even if we have developed the processing automation according to developing technology, we are also realized on increasing the human fatal risk cause of unexpected accidents. This study is directed the solution of decision for safety level for safety system and the best architecture for safety system in process automation.

• IE interfaces
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• v.25 no.4
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• pp.376-381
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• 2012

As the number, complexity and interaction of electrical, electronic and programmable electronic (E/E/PE) systems increase, a growing emphasis has been placed on the concept of functional safety during product development. IEC 61508 provides guidelines and standardized procedures in the development of reliable and dependable E/E/PE systems to assure functional safety. Determining risk classes (i.e., safety integrity levels, SILs) associated to a specific E/E/PE item may be recognized as one of the most crucial activities in the product development per IEC 61508 since SILs are used to specify necessary safety requirements for achieving an acceptable residual risk. This article presents a case study on the assessment of SILs applying failure modes, effects and diagnostic analysis (FMEDA) from which failure rates may be derived for each important failure category by combining a standard FMEA with online diagnostic techniques.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.6
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• pp.447-460
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• 2012

In this study, the shutdown system of the fuel gas supply system is designed based on the Safety Integrity Level of IEC 61508 and IEC 61511. First of all, the individual risk($10^{-4}$/year) and the risk matrix which are the risk acceptance criteria are set up for the qualitative risk assessment such as the HAZOP study. The natural gas leakage at the gas supply pipe is identified as the highest risk among the hazards identified through the HAZOP study and as a safety instrumented function the shutdown function for leakage was defined. SIL 2 and PFD($2.5{\cdot}10^{-3}$) for the shutdown function are determined by the layer of protection analysis(LOPA). The shutdown system(SIS) carrying out the shutdown function(SIF) is verified and designed according to qualitative and quantitative requirements of IEC 61508 and IEC 61511. As a result of SIL verification and SIS conceptual design, the shutdown system is composed of two gas detectors voted 1oo2, one programmable logic solver, and two shutdown valve voted 1oo2.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1303-1305
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• 2003

It is very important to ensure system safety during the process of developing a system. Railway system is also devoting a great portion for the safety. Nowadays many countries leading railway industry have their own system assessment principles according to the situation of their train control systems. In this paper, several principles to derive Safety Integrity Level (SIL) are represented in the railway signalling system. The characteristics of those principles are also considered respectively.

• IE interfaces
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• v.25 no.4
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• pp.422-430
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• 2012

In this article, we introduced the estimation method by 'Safety Integrity Level'(SIL) for the criterion of safety assurance and performed a case study on a flame scanner. SIL requires probabilistic evaluation of each set of equipment used to reduce risk in a safety related system. FMEDA(Failure Modes, Effects and Diagnostic Analysis) method is widely used to evaluate the safety levels and provides information on the failure rates and failure mode distributions necessary to calculate a diagnostic coverage factor for a part or a component. Basically, two parameters resulting from FMEDA are used for SIL classification of the device : SFF(Safe Failure Fraction) and PFD(Probability of Failure on Demand). In this case study, it is concluded that the flame scanner is designed to fulfill the condition of SIL 3 in the aspect of SFF and PFD.