• Journal of the Korean Society for Railway
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• v.8 no.5
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• pp.470-476
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• 2005

RCM developed by American air industry in early 1960, its process is most realistic for some physical assets and it permits the system to maintain given function status through decision of demand about optimum maintenance. Therefore, many industries have selected RCM technique and have carried out RCM in order to solve many problems concerning maintenance management as improvement of reliability and availability of facilities, removal of hazard element about break down and retrenchment of maintenance cost. Through the execution of RCM, we can solve actual problems. And finally we will be able to develop more and more maintenance activities with RCM notion. In this study, we will consider the application of KTX-RCM which is set up with basic theory of RCM and constructed to improve vehicle safety, availability and regularity of KTX, linking with CMMS(Computerized Maintenance Management System).

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.162-168
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• 2009

FMEA(Failure Mode and Effect Analysis) is a failure analysis method for the system to identify the potential failure modes, and their effects and causes to reduce or mitigate the critical effects of the system. FMEA for railway was introduced with reliability of railway system, and this was used for identifying and analysing the possible hazards qualitatively to meet the requirements in early stage of business. In general, the overall failure data of system could be managed from design stage by FMEA, and also the countermeasures to prevent many predicted failures could be established by identification of failure modes and assement of failure effects by FMEA. Using these advantages of FMEA, the effectiveness of reliability improvement could be expected if FMEA is applied continuously in operation stage. It is essential that railway vehicles are maintained with high level of safety and reliability not to happen any failures in operation. This paper is proposed the proper FMEA for maintenance of railway vehicles compared with existing FMEA.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.334-340
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• 2017

Reliability is considered a particularly important design factor for systems that have critical results once a failure occurs in a system, such as trains, airplanes, and passenger ships. The reliability of the system can be improved in several ways, but in a system that requires considerable reliability, the redundancy of parts is efficient in improving the system reliability. In the case of duplicating parts to improve reliability, the kind of parts and the number of duplicating parts should be determined under the system reliability, part costs, and resources. This study examined the redundancy allocation of multi-level systems with serial structures. This paper describes the definition of a multi-system and how to optimize the kind of parts and number of duplications to maximize the system reliability. To optimize the redundancy, the cuckoo search algorithm was applied. The search procedure, the solution representation and the development of the neighborhood solution were proposed to optimize the redundancy allocation of a multi-level system. The results of numerical experiments were compared with the genetic algorithm and cuckoo search algorithm.

• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.199-203
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• 1999

A framework for assessing seismic safety is suggested in this paper. The concepts of requirement and achievement are used in this framework. The quantified correlation between requirement and achievement derived from two competing variables results in the unconditional frequency of exceeding a damage level. This framework can be applied to any other external safety assessment of nuclear power plants.

• Journal of Digital Contents Society
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• v.16 no.1
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• pp.79-83
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• 2015

This paper suggested a cyber collaboration platform based on web for food safety service. We implemented the cyber collaboration platform for food safety service so that the users participated in collaborative work may refer shared media objects as the same view to others. In this paper, we discussed a model for increasing reliability of food safety data through N screen server and client model. This paper explained a performance analysis of a system with function comparison running on multimedia collaboration work based on web and N screen techniques.

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.463-478
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• 2019

The most important non-functional requirements for dependability of any Embedded Real-Time Safety Systems are safety, availability and reliability requirements. System architecture plays the primary role in achieving these requirements. Compliance with these non-functional requirements should be ensured early in the development cycle with appropriate considerations during architectural design. In this paper, we present an application of system architecture modeling for quantitative assessment of system dependability. We use probabilistic model checker (PRISM), for dependability analysis of the DTMC model derived from system architecture model. In general, the model checking techniques do not scale well for analyzing large systems, because of prohibitively large state space. It limits the use of model checking techniques in analyzing the systems of practical interest. We propose abstraction based compositional analysis methodology to circumvent this limitation. The effectiveness of the proposed methodology has been demonstrated using the case study involving the dependability analysis of safety system of a large Pressurized Water Reactor (PWR).

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.37-47
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• 2013

Due to the evolution of war fields to the net-centric one, weapon systems have become very complex in terms of both mission capability and implementation scales. In particular, the net-centric war field is characterized by a set of interconnected and independently operable weapon systems. As such, the individual weapon systems are required to meet the interoperability and thus, assuring it has been becoming more crucial even in the early stage of development. Furthermore, the ever-growing complexity of the weapon systems has attracted a great deal of attention on the safety issues in the operation and development of weapon systems. The objective of the study is on how to assure the interoperability for safety-critical weapon systems while maintaining system complexity. To do so, the approach taken in the paper is to consider the interoperability from the early stage of the development. Specifically, the required functions to satisfy the interoperability are developed first. The functions are then analyzed in order to link the safety requirements to the reliability evaluation, which results in the study of quantifying the effects of the safety requirements on the system as a whole. As a result, we have developed a methodology and procedure on how to assure interoperability while applying the safety requirements in the weapon systems development.

• Proceedings of the Safety Management and Science Conference
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• 2010.11a
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• pp.35-39
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• 2010

The research classifies three types of asymptotic tail distributions such as long(heavy, thick) tailed distribution, medium tailed distribution and short(light, thin) tailed distribution. The extreme value distributions(EVD) classified in this paper can be used in SPC(Statistical Process Control) control chart and reliability engineering.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.336-338
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• 2006

Motorized retractors enhance the safety of passengers by removing the slack of webbing and by holding upright driving position. Reliability of a driving mechanism that includes one-way clutch between the driving motor and webbing is directly linked to the safety of passenger. In this research, conditions for locking one-way clutch and also conditions for sustaining locking are theoretically investigated. the operation of a motorized retractor under realistic conditions is simulated in order to validate the proposed retractor design.

• Proceedings of the Safety Management and Science Conference
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• 2000.11a
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• pp.39-52
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• 2000

This paper is concerned with the method of estimating lifetime distribution for field data in warranty period and for a situation where some additional field data can be gathered after the warranty period. Implementing the proposed methods in this paper will result in obtaining the more precise product life time estimation and product improvement.