• 한국데이터정보과학회:학술대회논문집
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• 2002.06a
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• pp.17-22
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• 2002

Availability is an important characteristic of a repairable component. Iyer(1992) obtained the 'limiting efficiency'(not the `steady state availability') of the age-dependent minimal repair model which was first considered by Block et al.(1985). However the existence of the steady state availability of the model has not been reported. In this note, the existence of the steady state availability of the model is shown and a brief remark on the importance of the property is given.

• Communications for Statistical Applications and Methods
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• v.10 no.1
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• pp.191-202
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• 2003

Availability is an important measure of performance of a repairable component. In this paper, the explicit expression for the availability of a repairable component, which is subject to the policy II(Age Replacement Policy) of Barlow and Hunter (1960), is obtained and the existence of the steady state availability is shown. The steady state availabilities of the model are also obtained for the cases when the mean of the minimal repair time is increasing at a geometric rate or linearly increasing, In order to show the importance and the utility of the obtained result, we also consider an illustrative example of the repairable coherent system whose components are repairable, and the obtained results are applied to derive the steady state availability of the whole system. In this situation, we can see that the condition of the existence of the steady state availability for each component is essential. Some remarks on the optimal replacement policy that maximizes the steady state availability are also given.

• Journal of the Korean Institute of Navigation
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• v.17 no.1
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• pp.91-98
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• 1993

This paper presents a class of Bayes estimation of component steady-state availability . Throughout this paper, we will denote the mean time between failure and the mean time between repair by MTBF and MTBR respectively. In section 2 , we investigated Bayes estimation of the steady-state availability for noninformative prior density function and in section 3, we compute Bayes estimation for conjugate prior density function.

• Journal of Applied Reliability
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• v.14 no.1
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• pp.1-9
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• 2014

One important measure of performance for a repairable system is steady-state availability. In this paper, a method to estimate and establish confidence interval for the steady-state availability under Weibull lifetime and lognormal repair time distributions is proposed. Also, bias and mean squared error of a point estimator for an availability are investigated. In addition, a procedure to derive the sample size and critical value for availability demonstration test is presented and illustrated with a numerical example.

• International Journal of Reliability and Applications
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• v.2 no.2
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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.

• International Journal of Reliability and Applications
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• v.3 no.3
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• pp.147-154
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• 2002

In this paper, we consider the warm standby redundant system(WSRS) which is consisted 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. For the performance evaluation of a redundant system with the function of switchover processing which is assumed to cause the increase of the failure rate of the system, some reliability indices, such as availability, average availability, reliability and steady state availability, are considered.

• Journal of the Korean Society of Systems Engineering
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• v.14 no.1
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• pp.36-43
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• 2018

The availability of the weapon system can be analyzed through state modeling and simulation using the Markov process. In this paper, show how to analyze the availability of the weapon system and can use the Markov process to analyze the system's steady state as well as the RAM at a transient state in time. As a result of the availability analysis of tracked vehicles, the inherent availability was 2.6% and the operational availability was 1.2% The validity criterion was defined as the case where the difference was within 3%, and thus it was judged to be valid. We have identified the faulty items through graphs of the number of visits per state among the results obtained through the MPS and can use them to provide design alternatives.

• Proceedings of the Safety Management and Science Conference
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• 2007.04a
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• pp.309-322
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• 2007

This paper shows application guide of dependability data from the field, life cycle costing, and maintainability. Moreover, this study introduces mathematical expressions and predictions for reliability, availability and maintainability. This paper also shows compliance test procedures for steady-state availability, and application of Markov techniques.

• Proceedings of the Korean Reliability Society Conference
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• 2000.04a
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• pp.193-200
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• 2000

In this paper, we consider confidence limits for steady state availability of a redundant structure with the function of switchover processing. The system considered in this paper consists of three units which are an active unit, a standby unit and a switchover device. A control module does not affect the performance of the system while the active unit is operating but causes the system failure if the active unit fails at the failure of the control module. The effect of failure of control module is included in our reliability model of the simple redundant structure. The availability of the system is obtained by using the state space method. An example is given to illustrate our results.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.295-304
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• 2016

Purpose: This paper presents an application of Markov Process to reliability and availability analysis. In order to do that of analysis, we set up a specific case of Tablet PC and it's usage scenario. The case has it some spares and maintenance and repair processes. Methods: Different configurations of the tablet PC and as well as their functions are defined. The system configuration and calculated failure rates of components are modeled from Windchill Quality Solution. Two models, without a spare and with spare, are created and compared using Markov Process. The Matlab numerical analysis is used to simulate and show the change of state with time. Availability of the system is computed by determining the time the system stays in different states. Results: The mission availability and steady-state condition availability in accordance with the mission are compared and the availability of the system with spares have improved availability than without spares. Simulated data shows that downtime of the system increased which results in greater availability through the consideration of spares. Conclusion: There's many techniques and methods to do reliability and availability analysis and mostly are time-independent assumptions. But Markov Process, even though its steady-state and ergodic properties, can do time analysis any given time periods.