• 대한안전경영과학회지
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• 제8권5호
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• pp.253-264
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• 2006

This paper is to derive three reliability and eight maintainability measures after organizing total time. I propose inherent availability,.achieved availability and operational availability with the new and useful reliability and maintainability measures above. Especially, inherent availability measure extends the repairable system reliability models.

• 대한안전경영과학회지
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• 제10권4호
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• pp.159-163
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• 2008

This paper proposes various measures of reliability, maintainability and availability in information technology service management(ISTM). Global ITSM standards such as ITIL(IT Infrastructure Library) and ISO/IEC 20000 are introduced. Especially availability management of De-facto and De-juire standards is concerned with users and customers of IT service. The study presents seven reliability measures, six maintainability measures and two availability measures. These results can be effectively used with a appropriate IT availability management tools such as CFIA(Component Failure Impact Analysis) and SOA(Service Outage Analysis), etc.

• 융합보안논문지
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• 제20권2호
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• pp.53-58
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• 2020

지식정보사회에서 기업의 비즈니스 연속성을 담보하기 위한 가용성의 중요성이 대두되면서, 가용성 보장전략으로 지속적인 서비스 인프라를 구축하는 고가용성(HA, High Availability) 구현 방안을 제시하고 있다. 하지만, 정보자산에 대한 중요도 평가의 신뢰도가 확보되지 않는다면 실제 자산의 가치와 연계되어 보안성을 유지하기 어렵기 때문에 자산가치 매트릭스를 통해 평가된 자산 중요도를 바탕으로 가용성 기준인 서비스 유지 평가항목과 매핑하여 관리할 수 있는 가용성 평가 방안이 필요하다. 이에 본 연구에서는 정보 자산에 대한 가용성 평가 방안을 제시한다.

• International Journal of Advanced Culture Technology
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• 제8권3호
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• pp.292-299
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• 2020

This paper presents an evaluation criteria of an information system availability for guaranteeing availability (service target level) from the perspective of the SLA contract and its technical point of view. In order to verify the effectiveness for information system failure and availability guarantee measures, three cases were examined. In summary, the failure time was reduced by 32% ~ 62% after applying the availability guarantee measure, verifying the excellence in the evaluation of an information system availability.

• 대한안전경영과학회지
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• 제14권2호
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• pp.147-158
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• 2012

This paper aims to develop a new chain metrics for obtaining lean Overall Equipment Effectiveness(OEE) and present implementation strategy which considers the properties for Total Productive Maintenance(TPM) to reduce machine losses, Performance Analysis and Control(PAC) to reduce labor losses, Lean Production System(LPS) to reduce floor wastes, and Theory of Constraints(TOC) to minimize the problem of Capacity Constrained Resource(CCR). The study reviews the related literatures and reformulates the structure of machine losses, labor losses and field wastes. The research also develops the integrated productivity metrics according to time, units, reliability and maintainability. It is found that the study develops the actual productivity measure in terms of efficiency, effectiveness and standard productivity. In addition to that, it outlines and develops by using the integrated LPS and TPM, lean OEE measures such as Time Based Productivity(TBP), Unit Based Productivity(UBP), and Reliability & Maintainability Based Availability(RMBA). Implication examples are proposed to make it easier and available for practioners to understand the implementation strategies about TPM OEE, lean OEE and TOC OEE. Futhermore related to other studies, the research contributes to create a new chain productivity measures to clear the interrelationship concepts of productivity, efficiency and effectiveness. Moreover the paper develops the enhanced OEE measures by integration of TPM, PAC, LPS and TOC with the perspective of schedule, throughput, reliability, maintainability and availability.

• ETRI Journal
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• 제5권1호
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• pp.10-16
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• 1983

복잡한 시스템의 신뢰도를 해석하기 위해서는 가용도 (Availability) 및 각종 고장간격 등의parameter를 계산하여야 한다. 따라서 이들 parameter를 정의하고 이의 적용성에 대하여 언급하였으며, Markov process를 적용하여 각종 고장간격을 계산하는 기법을 유도하였다. 본 Markov process에 의한 신뢰도 해석기법은 제반 시스템의 상태확률을 계산하여 각종parameter를 구하게 되므로 다양한 시스템의 상태를 해석할 수 있으며, 시스템의 신뢰도 예측은 물론 정비계획을 수행하는 데에도 광범위하게 응용할 수 있다.

• 한국산업정보학회논문지
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• 제12권1호
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• pp.80-86
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• 2007

The concept of the coverage has been played an important role in the area of reliability evaluation of a system. The widely used measures of reliability include the m time between failures, the availability and so on. In this paper, we propose an estimator of the coverage probability in a redundant system with a control unit and investigate some moments of the proposed estimator. And assuming exponential distribution of all units, we conduct a simulation study for calculating the estimates of the coverage probability and its confidence bounds. An example of evaluating the availability of an optical transportation system is illustrated.

• 스마트미디어저널
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• 제6권3호
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• pp.95-102
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• 2017

A large volume of research has been devoted to the development of security tools for protecting the Smart Grid systems, however the most of them have not taken the Availability, Integrity, Confidentiality (AIC) security triad model, not like CIA triad model in traditional Information Technology (IT) systems, into account the security measures for the electricity control systems. Thus, this study would propose a novel security framework, an abnormal behavior detection system, to maximize the availability of the control systems by considering a unique set of characteristics of the systems.

• 대한안전경영과학회지
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• 제14권1호
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• pp.225-233
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• 2012

The research discusses interrelationship of structural and reliability importance measures which used in the probabilistic safety assessment. The most frequently used component importance measures, such as Birnbaum's Importance (BI), Risk Reduction (RR), Risk Reduction Worth (RRW), RA (Risk Achievement), Risk Achievement Worth (RAW), Fussel Vesely (FV) and Critically Importance (CI) can be derived from two structure importance measures that are developed based on the size and the number of Minimal Path Set (MPS) and Minimal Cut Set (MCS). In order to show an effectiveness of importance measures which is developed in this paper, the three representative functional structures, such as series-parallel, k out of n and bridge are used to compare with Birnbaum's Importance measure. In addition, the study presents the implementation examples of Total Productive Maintenance (TPM) metrics and alternating renewal process models with exponential distribution to calculate the availability and unavailability of component facility for improving system performances. System state structure functions in terms of component states can be converted into the system availability (unavailability) functions by substituting the component reliabilities (unavailabilities) for the component states. The applicable examples are presented in order to help the understanding of practitioners.

• 한국시뮬레이션학회논문지
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• 제21권2호
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• pp.103-112
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• 2012

전통적인 시스템 차원에서의 신뢰도 분석 모형에서 탈피하여 사용자가 인지하는 서비스 가용도에 대한 필요성이 대두되고 있다. 본 논문에서는 우선 서비스 가용도 모형에 대해 살펴보고 이의 근간을 이루는 UBG에 대하여 논하였다. 그리고 사용자 모델, 시스템 모델 및 서비스 모델을 복합적으로 고려하여 서비스 가용도를 산출하는 시뮬레이션 모델을 제안하였다. 아울러 예제를 통하여 사용자 모델의 UBG와 시스템 모델을 작성하고 이를 토대로 서비스 모델을 정의하는 일련의 과정을 보여 주었다. 그리고 시스템 모델과 UBG의 여러 파라메타들이 서비스 가용도에 미치는 영향에 대해 살펴보았다.