• The Korean Journal of Community Living Science
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• v.26 no.1
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• pp.5-18
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• 2015

This descriptive study investigates the need for, satisfaction with, and availability of local healthcare services for elderly individuals. The subjects included 210 individuals aged 65 years over, and data were analyzed using SPSS. The subjects reported the limited availability of local healthcare services but a high level of satisfaction with and a strong need for these services. The subjects used these services mainly for their vaccination and perceived cost-effectiveness as the most important factor motivating their decision to use these services and a lack of publicity as the most important factor discouraging their use. Spouses, jobs, and health conditions showed significant differences in the level of satisfaction and availability, and diseases showed significant differences only in the need. These results suggest that local healthcare centers should provide services that many elderly patients can use through outreach services, connections to local communities, and active publicity instead of expanding service types.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.157-164
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• 2012

When designing a multifunctional system consisting of many components performing many functions or missions, it is important to determine the reliability, availability, and maintainability (RAM) of the system and components, and we consider system availability to be the optimization criterion. For given intervals of mean time between failure (MTBF) and mean time to repair (MTTR) of the components, we want to determine the values of MTBF and MTTR for all components that satisfy the target availability. A heuristic method is proposed for finding near-optimal solutions through simulation. We also study numerical examples to check effects of model parameters on the optimal solutions.

• International Journal of Reliability and Applications
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• v.11 no.2
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• pp.89-106
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• 2010

This paper deals with the reliability and availability characteristics of three different series system configurations with warm standby components and a repairable service station. The failure time of the primary and warm standby are assumed to be exponentially distributed with parameters ${\lambda}$ and ${\alpha}$ respectively. The repair time distribution of each server is also exponentially distributed with parameter ${\mu}$. The breakdown time and the repair time of the service station are also assumed exponentially distributed with parameters ${\gamma}$ and ${\beta}$ respectively. We derive the reliability dependent on time, availability dependent on time, the mean time to failure, $MTTF_i$, and the steady-state availability $A_i$(${\infty}$) for three configurations and perform comparisons. Comparisons are made for specific values of distribution parameters and of the cost of the components. The three configurations are ranked based on: $MTTF_i$, $A_i$(${\infty}$), and $C_i/B_i$ where $B_i$ is either $MTTF_i$ or $A_i$(${\infty}$).

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.264-270
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• 1998

This research broadens the prime concern of nuclear power plant operations from safe performance to both economic and safe performance. First emergency diesel generator is identified as one of main contributors for the lost plant availability through the review of plants forced outage records. The framework of an integrated architecture for performing modern on-line condition for operational availability improvement is configured in this work. For the development of the comprehensive sensor networks for complex target systems, an integrated methodology incorporating a structural hierarchy, a functional hierarchy, and a fault-system matrix is formulated. The second part of our research is development of intelligent diagnosis and maintenance advisory system, which employs Bayesian Belief networks (BBNs) as a high level reasoning tool incorporating inherent uncertainty use in probabilistic inference. Our prototype diagnosis algorithms are represented explicitly through topological symbols and links between them in a causal direction. As new evidence from sensor network development is entered into the model especially, our advisory of system provides operational advice concerning both availability and safety, so that the operator is able to determine the likely modes, diagnose the system state, locate root causes, and take the most advantageous action. Thereby, this advice improves operational availability

• The Journal of the Korea Contents Association
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• v.12 no.11
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• pp.174-182
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• 2012

The purpose of the study is to establish a successful the national tax service electronic document system and suggest an application method by investigating relationships among perceived availability, perceived usefulness and system acceptance suggested by Technology Acceptance Model(TAM). As a result, perceived availability and perceived usefulness were playing roles as mediums on the process of accepting an tax electronic document system, and information quality of the electronic document system turned out to influence on perceived availability and perceived usefulness. And perceived availability turned out to influence on perceived usefulness. This suggests that the more tax officials feel comfortable in using an tax electronic document system, the more useful they perceive it is.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.4
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• pp.358-363
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• 2012

The simulation investigation on the availability of LNG plant with scenario of failure events and failure rate has been carried out. This study focuses on the availability, productivity, criticality induced by failure rate of major equipment. The methodologies for simulation such as the equipment classification of LNG plant and failure type and event schematic are established. The availability and mean time to repair have second order function profile in the all cases except general equipment, but these profiles have different inclination. The production and criticality of the specified LNG plant, simulated by Monte-Carlo algorithm, is located in the range of P = 86~92% and PL = 6~13%.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.3
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• pp.547-560
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• 2014

Smart Grid, which maximize the efficiency of energic utilization by applying Information and Communication Technology to Power Grid, requires high availability. Attacks, such as DDoS, which cause suspension of service and lead to social disruptions have recently been increasing so that systematic management over availability becomes more important. In this paper, we presents a new evaluation criteria of Korean Smart Grid by comparing availability assessment items of international standards specified in management system and then overcome the limitations of availability evaluation of existing information security management system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2634-2639
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• 2014

The idea of redundancy is used in order to improve the availability of networks and systems and there are various methods for implementing redundancy. To perform the availability analysis various stochastic models have been used. In this paper, 2N redundancy with one active service unit and one standby service unit is considered. To evaluate the expected availability, we model 2N redundancy using Stochastic Reward Nets. This model can be solved using the SPNP package.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.2
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• pp.238-240
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• 2016

Recently, the improvement in the data communication networks in terms of availability and reliability is emerging as a critical issue. In this context, the high availability and reliability of routers that control data flow and routing path between networks on the data communication network are being recognized as critical problems. Many methods for providing high availability to minimize the loss cost caused by the failure of a router are being studied. This paper proposed a BGP session takeover method using the Docker to support the high availability of the BGP session and to improve the takeover performance.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.547-550
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• 2008

Recently, changes in the environment of user-centric internet service such as blog, UCC and IPTV and ubiquitous computing based on web service are needed to high availability system platform. High availability system is to provide safe service continuously even if system failure occurs in clustering system at the network. And it is necessary to synchronize data for reliable service in high availability system. In this paper, I implement DRBD(Disk Replicated Block Device) which is synchronization technique for data of local disks in high availability system.