• Journal of Korea Society of Industrial Information Systems
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• v.5 no.4
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• pp.39-46
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• 2000

New products often have in-service reliability problem despite an intensive development program. Therefore reliability data must be collected and analyzed, and improvements designed and implemented. A type of reliability incentive contract which has recently attracted a lot of attention is reliability improvement warranty(RIW). It has been employed by military, airlines, telecommunication systems, and public utilities. An RIW contract requires that the supplies carries out all repairs, modify the equipment to improve its reliability, and provides all spates needed, for a fixed period, for once-off fee. This paper presents the reliability growth analysis and management methods for in-service MC68 microprocessor, which is the main component of the base station controller in PCS(Personal Communication Service) telecommunication system. The methods will provide guidelines to monitor reliability program in planning RIW contract.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.2
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• pp.241-248
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• 2019

In this paper, we aim to check the reliability growth of multiple launch rocket components by the life evaluation. We apply the Crow-AMSAA model to the sets of test data obtained from the development phase. The result of the data analysis shows that the reliability of some components needs to be improved. In order to improve their reliability, we analyze the failure mechanism and change their designs. The verification of the reliability growth for those components is done by analyzing the data sets obtained by the accelerated life tests. As a result, we show that the MTBF of those components is increased and also their reliabilities improved.

• Journal of Applied Reliability
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• v.16 no.2
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• pp.162-170
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• 2016

Purpose: The purpose of this study was to analyze the failure modes of an auto transfer switch (ATS), determine the most common failure mechanisms, and iterate the design to improve reliability. Methods: We carried out failure mode and effect analysis (FMEA) to determine the failure modes and mechanisms. We identified the parts or modules that required improvement via two-stage quality function deployment based on FMEA, and improvements to reliability were monitored using the Gomperz growth model. Results: The main failure modes of the ATS were damage to, and deformation of, the stator / movable element due to repetitive movements. Five iterations of design modification were carried out, and the mean time to failure (MTTF) increased to 14,539 cycles, corresponding to 85% of the target MTTF. The Gompertz growth model indicates that the 10th iteration of design modification is expected to achieve the target MTTF. Conclusion: We improved the reliability of mechanical parts via failure mode analysis, and characterized the iterative improvements in the MTTF using the Gompertz growth model.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.2
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• pp.33-39
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• 2002

Accelerated life testing of a car is used to get information quickly on its life distribution. Test cars are no under severe conditions and fail sooner than under usual conditions. A model is fitted to the accelerated failure times and then extrapolated to estimate the life distribution under usual conditions. This paper presents an accelerated test md the reliability growth theory, and applies it to some subsystems of cars during their prototype and pilot testing. The data presented illustrates explicitly the prediction of the reliability growth in the product development cycle. The application of these techniques is a part of the product assurance function that plays an important role in product reliability improvement.

• Proceedings of the Safety Management and Science Conference
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• 2011.04a
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• pp.663-674
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• 2011

Continuing and Developing the growth, the company should focus on 'time to market of high quality production' and 'cost down'. Due to the complexity of the production, reliability is being one of the important factor. In this study, in particular, focus on parts reliability test improvement about printer product and proceeded. Need test improvement for time to market that is developed, and reduce expense with test period that is required at Reliability Test time of new parts and should high quality level of product. Finally huge Failure Cost (F-COST) occurs because quality level of product drops if parts that accomplish product does not ensure reliability and this is associated by malfunction in marketplace.

• Journal of the Korea Safety Management & Science
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• v.12 no.3
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• pp.153-162
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• 2010

Continuing and Developing the growth, the company should focus on 'time to market of high quality production' and 'cost down'. Due to the complexity of the production, reliability is being one of the important factor. In this study, in particular, focus on parts reliability test improvement about printer product and proceeded. Need test improvement for time to market that is developed, and reduce expense with test period that is required at Reliability Test time of new parts and should high quality level of product. Finally huge Failure Cost (F-COST) occurs because quality level of product drops if parts that accomplish product does not ensure reliability and this is associated by malfunction in marketplace.

• Proceedings of the Korean Society for Quality Management Conference
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• 2009.10a
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• pp.227-229
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• 2009

Recent discussions in the active growth strategy based on getting a green environment, changes in the management of companies involved in environmental management is the analysis of various risk factors and the green growth at the same time the company's growth strategy is required. Thus, the corporate position on the green growth strategy based on risk management to analyze and respond to face reality, and respond to the scene of the applied methodology is required. In this study, contact the section of Environment to assess potential business risks that the EMEA Environment Mode Effects Analysis methodology through research and development company's in, contact the section of Environment to effectively analyze risk management by addressing the degree of risk assessment as a future-oriented and objective can manage is to provide technical management model.

• Journal of Korean Society for Quality Management
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• v.26 no.3
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• pp.71-81
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• 1998

In reliability analysis, the time difference between the expected next failure time and the current failure time or the Mean Time Between Failure(MTBF) is of significant interest. Until recently, in reliability growth studies, the reciprocal of the intensity function at current failure time has been used as being equal to MTBE($t_n$)at the n-th failure time $t_n$. That is MTBF($t_n$)=l/$\lambda (t_n)$. However, such a relationship is only true for Homogeneous Poisson Process(HPP). Tsokos(1995) obtained the upper bound and lower bound for the MTBF($t_n$) and proposed an estimator for the MTBF($t_n$) as the mean of the two bounds. In this paper, we provide the estimator for the MTBF($t_n$) which does not depend on the value of the shape parameter. The result of the Monte Carlo simulation shows that the proposed estimator has better efficiency than Tsokos's estimator.

• Journal of Korean Society for Quality Management
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• v.39 no.2
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• pp.170-178
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• 2011

In general, a software fault detection phenonenon is described by a software reliability model based on a nonhomogeneous Poisson process(NHPP). In this paper, we propose a software reliability growth model considering the differences of the software environments in both the testing phase and the operational phase. Also, we consider the problem of determining the optimal release time and the optimal warranty period that minimize the total expected software cost which takes account of periodic software maintenance(e.g. patch, update, etc). Finally, we analyze the sensitivity of the optimal release time and warranty period based on the fault data observed in the actual testing process.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.1
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• pp.29-38
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• 1998

We summarize, in this paper, that we have learned from the slftwar reliability analysis of a large switching software composed of functional blocks which form slotware units. To determine the time of management activity related to sopftware reliability growth, we review the process of detection and correction of software failures. Also we apply the two softwre reliability frowth model, Goel-Okumoto and S-shaped model, to estimate the global software reliability growth to a set of failure found during period of the system test. The analysis methods and results can be applied to other large software development projects.