• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.64-69
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• 2012

The concept of SIL is applied in the most of all standards relating to functional system safety. However there are problems for the people to apply SIL to their plants. as these standards don't include sufficient informations. In this regards, this paper will suggest the direction of SIL application and concept based on IEC 61508 and IEC 61511. A Safety Integrity Level(SIL) is the discrete level(one out of possible fours), corresponding to a range of the probability of an E/E/PE (Electric/Electrical/Programmable Electrical) safety-related system satisfactorily performing the specific safety functions under all the stated conditions within a stated period of time. SIL can be divided into the target SIL(or required SIL) and the result SIL. The target SIL is determined by the risk analysis at the analysis phase of safety lifecycle and the result SIL is calculated during SIL verification at the realization phase of safety lifecycle. The target SIL is determined by the risk analysis like LOPA(Layer Of Protection Analysis), Risk Graph, Risk Matrix and the result SIL is calculated by HFT(Hardware Fault Tolerance), SFF(Safe Failure Fraction) and PFDavg(average Probability of dangerous Failure on Demand). SIL is applied to various areas such as process safety, machinery(road vehicles, railway application, rotating equipment, etc), nuclear sector which functional safety is applied. The functional safety is the part of the overall safety relating to the EUC and the EUC control system that depends on the correct functioning of the E/E/PE safety-related systems and other risk reduction measures. SIL is applied only to the functional safety of SIS(Safety Instrumented System) in safety. EUC is the abbreviation of Equipment Under Control and is the equipment, machinery, apparatus or plant used for manufacturing, process, transportation, medical or other activities.

• Journal of the Korea Safety Management & Science
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• v.16 no.1
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• pp.79-88
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• 2014

The rapid growth of complexity and scale can be witnessed in the design and development of modern systems. As such, the severity of damages in the occasional accidents has attracted great deal of attention lately. Although a variety of methods have so far been studied to overcome or reduce the disastrous results of hazards, the issues seem still persistent and even complicated due to the situation mentioned above. The concept of functional safety has been regarded as one approach to handling the matters by shifting up to the functions level from the consideration of each physical component itself. The outcomes of those efforts would be the international standards on functional safety such as IEC 61508 and its relatives including IEC 62278, EN 50128, ISO26262, and so on. In this paper, a method of how hazards can be analyzed to be coped with those standards has been studied. In the method proposed, the systems modeling language (SysML) is playing a key role to model and analyze the hazards from the viewpoint of functional safety. The approach taken has been applied in the analysis of the hazards in railroad systems. In spite of focusing on the individual components hazards, the method based on functional safety has analyzed them collectively with the added effect of identifying the cause originated from the interface between the functions.

• 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 Korea Safety Management & Science
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• v.16 no.1
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• pp.69-77
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• 2014

The environment and requirements of modern war fields have been affected and thus changed by a variety of issues. To this end, the development of safety-critical weapon systems frequently need to meet those changes even in the operational phase. The necessity of the changes may be due to the preparation for mass-production or the request originated from the user military forces. To meet such a need can be even tougher in the development of safety-critical weapon systems since the integration of the requirements for both systems design and systems safety would make it troublesome. To handel the matter in this paper, utilization of architecture DB is proposed. Specifically, the situation in demand has first been analyzed and then a problem-solving process to accommodate the design changes has been constructed. In doing so, the concept of the aforementioned integration is particularly focused on the functional architecture, which could be a core concept of our approach to solving the problem. The result of a case study demonstrating the method studied using a computer-aided systems engineering tool is also presented.

• Journal of the Korea Safety Management & Science
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• v.10 no.4
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• pp.73-81
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• 2008

The current electrical safety plan developed for the national electricity system has been playing an important role in handling a variety of electrical accidents. However, it can be more effective to prevent or reduce those accidents if a preventive electrical safety plan is available. In this paper, an approach to developing the safety plan is described. We first discuss the contents that should be included in the plan. Noting that an effective plan requires the system level consideration of all the factors affecting the safety issues, an operation concept document (OCD) is considered. The OCD can allow us to understand the behavior of the safety system based on the operation environment, the system functions, the performance requirements, all at the system level of the safety system. Thus, the OCD can be useful in developing the safety plan. A detailed description then follows on how the OCD is developed for the electrical safety system under study. Finally, we discuss how the developed OCD can be used in deriving the preventive electrical safety plan.

• Journal of Auto-vehicle Safety Association
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• v.16 no.3
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• pp.7-17
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• 2024

Ensuring an automated fallback strategy in response to malfunctions during the execution of the Dynamic Driving Task (DDT) is imperative for Level 4 autonomous driving systems. While Triple Modular Redundancy (TMR) represents a prominent Fail-Operational structure, its practical application to multiple systems is constrained by the substantial increase in costs. In this paper, we propose a pragmatic Fail-Operational safety concept utilizing on-board camera sensors and the Vehicle-to-Infrastructure (V2I) communication module, known as the On-Board Unit (OBU), to provide traffic signal information within the vehicle. The viability of the designed safety concept is validated through error injection simulations. This approach addresses the practical limitations associated with applying Fail-Operational functionality to numerous systems due to the considerable cost escalation. Leveraging camera sensors and V2I communication modules presents a practical and cost-effective solution for maintaining operational safety in Level 4 autonomous driving systems, particularly when responding to malfunctions in the DDT.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.333-338
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• 2007

The concept of "Allowable Load Set (ALS)" introduced by the author allows an easy understanding of load and strength characteristics of a structure in relation to its integrity under uncertainties. Two criteria of safety are introduced: A relative safety index denotes the distance to the boundary of the ALS and a normalized safety index is a distance in terms of functional value. They have been utilized in several examples, including multi-body mechanical systems such as a biomechanical system. Both formulations amount to robust designs in the sense that designs most insensitive to uncertainties are obtained in the context of newly defined safety indices, without using any input probability information.

• Journal of the Korean Society of Safety
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• v.26 no.1
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• pp.65-70
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• 2011

Resilience has been suggested as a new paradigm of disaster management which reduces losses against disasters under the uncertain circumstances. The purpose of this study is to define the concept and to set up the objectives of urban resilience for disaster management. The common concept and components of resilience were analyzed by examining recent studies on resilience. The resilience was defined as "a capacity of physical and social urban elements adapting and recovering against disaster for better condition" and the five objectives of resilience - Robustness, Redundancy, Resourcefulness, Rapidity, and Regional Competency - were derived from the review of literatures. The major disasters and accidents were analyzed focused on those objectives. The concept and objectives of urban resilience could be used as a guidance for disaster prevention planning and disaster management processes.

• Safety and Health at Work
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• v.12 no.1
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• pp.10-19
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• 2021

Background: Traditional safety concept, which is called Safety-I, and its relevant methods and models have much contributed toward enhancing the safety of industrial systems. However, they have proved insufficient to be applied to complex socio-technical systems. As an alternative, Safety-II and resilience engineering have emerged and gained much attention for the last two decades. However, it seems that safety professionals have still difficulty understanding their fundamental concepts and methods. Accordingly, it is necessary to offer an introductory guide to them that helps safety professionals grasp them correctly in consideration of their current practices. Methods: This article firstly explains the limitations of Safety-I and how Safety-II can resolve them from the four points of view. Next, the core concepts of resilience engineering and Functional Resonance Analysis Method are described. Results: Workers' performance adjustment and performance variability due to it should be the basis for understanding human-related accidents in socio-technical systems. It should be acknowledged that successful and failed work performance have the same causes. However, they are not well considered in the traditional safety concept; in contrast, Safety-II and resilience engineering have conceptual bases and practical approaches to reflect them systematically. Conclusion: It is necessary to move from a find-and-fix and reactive approach to a proactive approach to safety management. Safety-II and resilience engineering give a set of useful concepts and methods for proactive safety management. However, if necessary, Safety-I methods need to be properly used for situations where they can still be useful as well.

• Journal of Korean Society for Quality Management
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• v.41 no.2
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• pp.185-196
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• 2013

Purpose: This paper is focused on introducing the Automotive Functional Safety International Standard-ISO 26262 and proposing effective countermeasures of ISO 26262. Methods: We studied collected data about ISO 26262 and analyzed the relationship between ISO 26262 and Quality 5 Star of Hyundai Kia Motors for the integrated product development process. Results: Results showed the product development process for the integration plan between ISO 26262 and Quality 5 Star. In addition, we added an entry about the functional safety in the evaluation item of Quality 5 Star System. Conclusion: In order to introduce ISO 26262 effectively, we proposed ISO 26262 requirements and functional safety concept to be added to Quality 5 Star.