• 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.

• 한국산업융합학회 논문집
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• 제24권6_2호
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• pp.827-839
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• 2021

Due to climate change and population growth, water scarcity is getting worse all over the world. Among various methods for desalination of seawater, the Multi-Effect Adsorptive Desalination method, which combines the existing Multi-Effect Desalination method and the Adsorptive Desalination method and can produce high-concentration-high-concentration freshwater, is emerging. Because the Multi-Effect Adsorptive Desalination method combines the two different methods, the system becomes complicated and the possibility of failure increases. Therefore, in this study, availability analysis was performed on the Multi-Effect Adsorptive Desalination process. A total of four types of reliability block diagrams were presented, and availability analysis was conducted based on them. The first form of a reliability block diagram is configured in series without any redundancy. The availability of the reliability block diagram composed of the serial system was found to be lower than the required availability. In order to increase availability, the redundancy to pumps and boiler are added to system. As a result of availability analysis, it was confirmed that designing desalination systems with redundancy to pump meets the 93% availability, which is typically required availability for various plants.

• 한국신뢰성학회지:신뢰성응용연구
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• 제10권2호
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• pp.149-160
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• 2010

This paper presents a study of an availability evaluation for I&C(Instrumentation and Control) System which it applied for nuclear power plant. The system availability assessment have been implemented to the reactor protection system by the adoption of Markov process. Results are satisfied to the requirement of EPRI and APR1400. Based on the research of I&C system assessment, it will contribute to improve the availability of system and impact the design concept with new design optimization.

• 산업경영시스템학회지
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• 제21권48호
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• pp.113-122
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• 1998

In this paper we consider the CSP requirements determination problem of new equipment(machine) system. For the newly procured equipment systems, mathematical analyses are made for the system which is constructed with the consumable parts to derive the associated CSP requirement determination model in mathematical expression. Based on these analyses, a mathematical model is derived for making an optimal CSP requirement determination subject to tile constraint of satisfying any given operational availability limitation. We assume that the failure of a part follows a Poisson process. Firstly, the operational availability concept in CSP is defined and the relation between the general system availability and the operational availability is established. Secondly, the problem is formulated as the cost minimization problem that should satisfy the operational availability limitation, and then, using the generalized Lagrange multipliers method, the optimal solution procedure is derived.

• 산업경영시스템학회지
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• 제23권59호
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• pp.53-67
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• 2000

In this paper we consider the CSP requirements determination problem of new equipment(machine) system. For the newly procured equipment systems, mathematical analyses are made for the system which is constructed with the consumable parts and the repairable parts to derive the associated CSP requirement determination model in mathematical expression. Based on these analyses, a mathematical model Is derived for making an optimal CSP requirement determination subject to the constraint of satisfying any given operational availability limitation. We assume that the failure of a part follows a Poisson process and the repair time has an exponential distribution. Firstly, the operational availability concept in CSP is defined and the relation between the general system availability and the operational availability is established. Secondly, the problem is formulated as the cost minimization problem that should satisfy the operational availability limitation, and then, using the generalized Lagrange multipliers method, the optimal solution procedure Is derived.

• 한국신뢰성학회지:신뢰성응용연구
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• 제8권4호
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• pp.193-204
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• 2008

In this paper, we proposed availability evaluation of network in mobile communication network that have hand off structure. Radio mobile communication network is essential hand off action to keep communication that is no discontinuance by transfer of terminal. Part by state and hand off state ago hand off by transfer of terminal and communication network is estimated performance according to the hand off rate and hand off completion rate of system. we applied MS, SM, MM communication structure in radio CORBA for network availability evaluate. System availability in mobile communication network that can repair that propose in this study uses the hand off rate and hand off completion rate of system by transfer of terminal and availability of whole system did evaluate.

• International Journal of Reliability and Applications
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• 제2권2호
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• pp.107-115
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• 2001

This paper considers some reliability indices, such as availability, average availability, reliability and steady state availability, of a redundant system with the function of switchover processing. We also derive the confidence limits for steady state availability of such system. The system, which is considered in this paper, consists of an active unit, a standby unit and a switchover device. In addition, the switchover processing is controlled by a control module. The effect of failure of the control module is taken into account to develop our reliability model for the redundant structure. Numerical examples are presented to illustrate our results.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2010년도 춘계 종합학술대회 논문집
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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.

• 한국국방경영분석학회지
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• 제16권2호
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• pp.83-95
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• 1990

This paper addresses the problem of determining the optimal number of spares for a system consisting of multi-item parts. In commercial sector, the cost minimization is mainly considered as an objective functions in most inventory models. However, in the military inventory systems, it is more stressed on maximizing the system availability than minimizing the system cost because the field commander always wants the system to be in perfect working condition to prepare against an emergence case. In this point of view, this paper develops an inventory model which decides the optimal number of spares by minimizing units short and simultaneously achieving a certain level of system availability. Solution algorithms are derived using the generalized Lagrange multiplier approach and marginal analysis approach. Sample data and output results are provided and sensitivity analysis is performed as the level of system availability changes in order to decide the optimal number of spares and availability in terms of economic sense.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.88-88
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• 2000

As more and more critical commercial applications move on the Internet, providing highly available servers becomes increasingly important. One of the advantages of a clustered system is that it has hardware and software redundancy. High availability can be provided by detecting node or daemon failure and reconfiguring the system appropriately so that the workload can be taken over bi the remaining nodes in the cluster. This paper presents how to provide the guaranteeing high availability of clustering web server. The load balancer becomes a single failure point of the whole system. In order to prevent the failure of the load balancer, we setup a backup server using heartbeat, fake, mon, and checkpointing fault-tolerance method. For high availability of file servers in the cluster, we setup coda file system. Coda is a advanced network fault-tolerance distributed file system.