• Journal of Applied Reliability
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• v.16 no.4
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• pp.272-279
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• 2016

Purpose: In order to fulfill the RAMS (Reliability Availability Maintainability and Safety) requirements in Korean railway systems, specific target metrics should be measured and met the requirements when ordering a new system. This paper presents a procedure to predict and demonstrate the availability, maintainability and safety of subway elevators, escalators and PSD (platform screen doors) systems. Methods: The system manufacturer predicts availability and maintainability with lab and field tested data. After installation, availability and maintainability are demonstrated based on the actual operational data. The data was collected from the FRACAS (Failure Report and Corrective Action System). Results: Methods and process of assessing and analyzing the availability, maintainability and safety are presented for elevating services and PSD systems. The data obtained through the actual operation of the equipment is analyzed and maintained to predict the RAMS based on the component and system level failure data acquired. Conclusion: This study presented an application using IEC 62278 and operational data which can be used in the design and development stage to achieve the RAMS target value of the subway elevators, escalators and PSD systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.9B
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• pp.818-825
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• 2004

High availability means Service-technology that can provide any solution when occur a problem in relation to hardware, software, network etc. We are in the times that the network computing service are essential to our daily life. So the importance of the high availability is being higher and higher in this social change such as the arrival of information anger times, e-commerce the extension of multi-media service etc. In this thesis, I analyzed about High-availability Linux Server for Multimedia Tourism Information System, and I proposed an alternative plan which related with its result.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.155-158
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• 1998

The KOMPSAT system incorporates multiple missions designed to provide various applications in the field of Korean peninsula observation covering land, sea and coastal zones. The missions are Korea cartography (1:25,000 scale maps of the Korean peninsula), biological oceanography and science instrument accommodation. The operational availability of KOMPSAT TTC system should be predicted more accurately because its failure has a significant influence on satellite command and tracking and on satellite data collection. In this paper, system availability structure of KOMPSAT TTC system are made and availability of KOMPSAT TTC system is analyzed aspect to the system operation in accordance with logistic condition.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.2
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• pp.87-93
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• 2009

In this paper, we propose and evaluate the availability of single sensor node using a hierarchial modeling approach. We divides a sensor node into a software and hardware and analyze failures of each component. We construct Markov chains to represent the components of a sensor node, and then we construct a hierarchical model which use fault tree in upper level and Markov chains in lower level. We evaluate the availability and down of single sensor node.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.184-185
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• 2021

On this paper, the availability of quantum technologies are studied and various attack methods to damage the availability of quantum technologies are studied.

• Korean Journal of Childcare and Education
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• v.6 no.1
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• pp.23-45
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• 2010

The purposes of this study were to explore the level of emotional availability of working mothers and their 24~48month-olds (67 dyads: 33 boys and 34 girls) in child care centers and to examine the relationship between the mother-child emotional availability and the related variables of working mothers and their children. Emotional Availability Scales (EA, 3rd edition) developed by Biringen, Z., Robinson, J., & and Emde, R.N. (1998) was used. Mother's work-family conflict, maternal parenting stress, and maternal depression, temperament of child, personal background were measured. The results of this study were as follows: The level of mother-child emotional availability was above in the middle level. There were significant differences in the mother-child emotional availability by maternal educational level and family income level, and significant negative correlation between maternal parenting stress and mother-child emotional availability. There was significant difference in the mother-child emotional availability by the starting point of child care experience. Mother-child emotional availability were significantly explained by family income level, maternal parenting stress, and the starting point of child care experience.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1717-1722
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• 2016

Availability, one of the important metrics used to assess the performance of network system, is defined as the probability that a system is operational at a given point in time under a given set of environmental conditions. To improve the availability of the network service, the redundancy models and the rejuvenation schemes are the effective schemes to be typically used. In this paper, we analyse the effect of 2N redundancy model and/or rejuvenation scheme on the availability of network service. The 2N redundancy model consists of one active and one standby component and the performance of time-based rejuvenation scheme mainly depends on its rejuvenation period. We design stochastic reward net model for the 2N redundancy model with time-based rejuvenation scheme and analyse the service availability of the model using stochastic Petri net package. We provide some numerical examples of the service availability, which shows that the system with rejuvenation has higher availability than the system without rejuvenation.

• Proceedings of the Korea Contents Association Conference
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• 2010.05a
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• pp.390-392
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• 2010

Mobile grid system supports the integration mobile devices as grid resources. Availability of mobile resources changes dynamically in mobile grid system. Stochastic reward nets (SRN) is an extension of stochastic Petri nets and provides compact modeling facilities for system analysis. We build the SRN model to represent availability of mobile resources with disconnected operation service.

• International Journal of Reliability and Applications
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• v.5 no.2
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• pp.75-80
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• 2004

Relationships between inventory policy and operational availability of military equipment maintained under a logistics support system are analyzed. A continuous review inventory model with a stochastic demand typically used in a military logistics support is considered and some numerical studies are provided.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.180-186
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• 1992

A system is considered which is required to perform several tasks which arrive randomly during the fixed mission duration.