• Proceedings of the Safety Management and Science Conference
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• 2010.11a
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• pp.651-668
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• 2010

철도 시스템은 차량, 전력, 신호, 선로구축물시스템이 유기적으로 결합된 복합시스템으로 사고 발생 시 원인규명이 어렵고 인명에 치명적인 결과를 초래하게 되며 사소한 고장이라도 열차지연에 미치는 파급효과는 지대하여 시스템의 신뢰성확보가 매우 중요하다[26]. 실제로 세계 각국의 철도산업은 시스템의 신뢰성 향상을 위해 신뢰성 기법에 기반을 둔 다양한 이론을 통해 신뢰성 향상과 안전성 향상에 최선을 다하고 있다. 본 연구에서는 철도 신뢰성관리와 관련된 국내 연구동향과 철도 운영기관 및 기업에서 적용하고 있는 신뢰성 적용 현황을 분석한다. 그리고 국외 연구 동향과 주요 적용 현황을 정리한다. 또한 철도 신뢰성과 관련된 국내외 규격을 조사하고 이들 규격의 내용을 분석한 후 국내 적용방향을 제시한다.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.6
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• pp.537-542
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• 2002

We propose new metrics for understandability and modifiability of class inheritance structures based on the object-oriented metrics suggested by Chidamber and Kemerer. The metrics are evaluated using the results of Gursaran s experiments which validated the empirical relation of DIT(Depth of Inheritance Tree) and NOC(Number of Children) metrics of Chidamber and Kemerer.

• Journal of Korean Society for Quality Management
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• v.39 no.3
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• pp.353-364
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• 2011

RAM(Reliability, Availability and Maintainability) is one of the important indicators to show the performance of weapon systems. For analyzing RAM characteristics, RAM simulation is useful and powerful as mathematical techniques. However, it is necessary to build the simulation model to express about the operation environment of weapon systems, and obtain detail input data for reliability and maintainability about the system to get accurate results by RAM simulation. In this paper, we propose a procedure to analyze RAM of the searching system consisting in weapon systems by RAM simulation and we estimate searching system availability by a commercial simulation program, AvSim.

• IE interfaces
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• v.18 no.4
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• pp.477-484
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• 2005

This paper is concerned with the life-cycle cost(LCC) of the urban transit system which was developed by KRRI and is now under test in Gyeongsan, Korea. Its reliability, availability and maintainability(RAM) were analyzed. LCC is the core part of analyzing the total cost of acquisition and ownership of a system. LCC analysis of a system is the most effective when it is applied in the it's early design phase. In this paper, we present IEC 60300-3-3(Life Cycle Costing) in detail and propose how to apply LCC in assessing the urban transit system according to RAM process. This case study demonstrates that reliability management system is very effective in reducing the operating cost of subway corporations in Korea.

• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.4
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• pp.141-156
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• 1999

Recently expanded and enhanced software system inevitably demands serious managerial considerations on its maintenance cost. This study proposes a systematic and thorough assessment model for software development methods to the end of maintainability, incorporation ISO 9126 quality standards-based criteria. The Analytic Network Process (ANP) is employed in our model to find the effect of any dependency among the items of the criteria and the alternative methods. This study then applies the model empirically in order to evaluate the efficacies of the Structured Method and the Objected-Oriented Method. At first, this study performs the test on the existence and direction of any dependency under the three types of assumptions, and then determines the relative dominance of the two methods.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.7
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• pp.59-70
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• 2012

This paper provides a model which is used for SOA based system's quality evaluation. This model make evaluation with "Reliability, Usability, Efficiency, Usability and Maintainability", these five aspects which were reference from ISO/IEC 9126. A systems based on SOA was tested by this model in these five aspects. As the results of the evaluation this system satisfied 61.45% users including Service Requester and Service Registry.

• Journal of the Korean Society of Systems Engineering
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• v.11 no.1
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• pp.49-54
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• 2015

The RAMS Process is the Internationally required activity to secure Reliability, Availability, Maintainability, and Safety of system which will be acquired as customer requirements. The importance are situations that have been growing gradually. Specially, When developing railway system, the needs of customer about RAMS Process has been being proposed in a variety of railroad business. Through this paper, It introduces the international standards described the RAMS Process and also presents the requirements that should have to comply with it. Furthermore, the necessary activities to get certificate of a Railway system are suggested and not only the various acquisition cases of certificate but also lessons learned by cases in the field of railway signalling system are presented.

• Journal of the Korean Society of Systems Engineering
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• v.10 no.2
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• pp.43-50
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• 2014

The Centralized Traffic Control(CTC) System of Urban Railway is an element(subsystem) of the Urban Railway system to aim safety operation and efficient management of rolling stock in accordance with a train scheduling program in train operation ways. That's why the CTC System must be developed considering systematic and safety-guaranteed methods such as RAMS(Reliability, Availability, Maintainability, and Safety) refereed to IEC standards. The CTC System is consists of rolling stock, signaling, power supply, communication, and mechanical equipment and preforms control and remote monitoring functions. The technical activities considering safety process are very important at such an early stage of development in a railway project. This paper introduces RAMS activities and an independent safety assessment by $3^{rd}$ Party focused on a safety applied to a development of the CTC system of Urban Railway and proposes the experiences as well practices.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.6
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• pp.102-116
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• 2008

In the development stage of weapon system, it is important to analyze RAM(Reliability, Availability and Maintainability) characteristics. RAM simulation is one of the advanced techniques for analyzing RAM to overpass the limit of mathematical techniques. However, it is necessary to obtain correct input data for reliability and maintainability about target and support system to get highly accurate results through RAM simulation. In this study, we propose the technical method to improve the results by defining input data of simulation more correctly based on analyzing effects of RAM characteristics by major factors.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.3
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• pp.127-134
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• 2009

RAM(Reliability, Availability, Maintainability) is important performance factor to keep combat readiness and optimize operational and maintenance cost of weapon systems. This paper discusses the method to establish RAM for combat readiness by using field failure data from similarity equipments. Operational availability is estimated from a binomial distribution function of user's operational conditions such as combat readiness preservation probability, operational rate, operational availability and total number of equipment. Reliability and maintainability is estimated from field failure data from similarity equipment to accomplish operational availability. The effectiveness of established RAM is verified through analysis of combat readiness preservation probability and mission reliability. A case study of weapon system illustrates the process of the proposed method.