• Corrosion Science and Technology
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• v.4 no.5
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• pp.201-206
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• 2005

Starting with the meaning of the word quality, diverse concepts connoted by the term are examined. Instead of a bathtub curve, the desirable shape of a failure rate covering the entire life of a good product, which might be called hockey-stick line, is introduced. From the hockey-stick line and the definition of reliability, two measurements are extracted. The terms r-reliability (failure rate) and durability (product life) are explained. The conceptual analysis of failure mechanics explains that reliability technology pertains to design area. The desirable shape of hazard rate curve of electronic items, hockey-stick line, clarifies that Mean-Time-to-failure (MTTF) as the inverse of failure rate can be regarded a nominal life. And Bx life, different from MTTF, is explained. Reliability relationships between components and set products are explained. Reshaped definitions of r-reliability and durability are recommended. The procedure to improve reliability and the reasons for failing to identify failure mode are clarified in order to search right solutions. And generalized Life-Stress failure model is recommended for the calculation of acceleration factor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1485-1486
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.789-790
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.1059-1060
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• 2010

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2527-2538
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• 2011

The Reliability started for MILitary purposes during World War II in 1942, getting more important for maintenance, safety, etc in modern society. As technologies develop, also international standards for measuring the reliability is advancing. RAMS activities for maintenance, safety verification is material to national railroad. And for this, it needs quick response for the changes of standards. Even now standards are upgrading for developing electronic technologies. Therefore analysis of failure rate's trend about such standards is judged necessary. So We submit a this paper for comparative analysis of changing process standards according to development of electronic technologies and reliability. At first, we compared actual usage ratio of standards for understanding the current state of usage. Based of these state of usage, discuss the major standard. And then, introduced reliability standards's trend, calculation method of failure rate and difference of failure rate calculation standard according to march of time. In this paper, used standards are MIL-HDBK-217F, Telcodia, etc.

• Journal of IKEEE
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• v.18 no.3
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• pp.313-319
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• 2014

The objectives of power system operations are to preserve system stability and reliability as well as to supply proper electric power. For an activation of these objectives, voltage and reactive power should be considered. There are a number of types about reactive power sources, and an insertion of shunt capacitor banks are one of the method to support bus voltage adjacent. This paper includes the design procedure to determine the hybrid type capacitor bank configurations on power system to improve stability and reliability. This procedure includes the capacitor bank capacity calculation, reactor type selection, and reactor capacity calculation. The total capacity calculation of capacitor bank is based on the reactive power margin which is calculated through system studies such as, contingency analysis and Q-V analysis. In the second step, the reactor type and its capacity can be determined through the harmonic analysis. This paper shows that the harmonics are decreased by the proposed hybrid type capacitor bank, especially 5th and 7th harmonics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.475-480
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• 1997

It is common to assum identical allowable safety factors in static strength, defined by mean stress and in fatigue, defined by stress amplitude. Under the load with asymmetrical cycles the safety factor is not the same. In this paper, with the consideration of unequal allowable safety factors a general method for estimating fatigue reliability of a machine element under a combined state of stress is derived based on the theory proposed by Prof. Kececioglu and normal distribution. The calculation of fatigue reliability for limited life is discussed with example.

• Journal of Korean Society for Quality Management
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• v.25 no.4
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• pp.71-78
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• 1997

In this paper, we consider a hierarchical Bayes estimation of the parameter, the reliability and failure rate functions based on type-II censored samples from a Burr type-？ failure time model. The Gibbs sampler a, pp.oach brings considerable conceptual and computational simplicity to the calculation of the posterior marginals and reliability. A numerical study is provided.

• Journal of Electrical Engineering and information Science
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• v.2 no.6
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• pp.123-130
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• 1997

This paper presents a generalized expansion method for calculating reliability index in power generation systems. This generalized expansion with a gamma distribution is a very useful tool for the approximation of capacity outage probability distribution of generation system. The well-known Gram-Charlier expansion and Legendre series are also studied in this paper to be compared with this generalized expansion using a sample system IEEE-RTS(Reliability Test System). The results show that the generalized expansion with a composite of gamma distributions is more accurate and stable than Gram-Charlier expansion and Legendre series as addition of the terms to be expanded.

• Journal of the Ergonomics Society of Korea
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• v.1 no.2
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• pp.11-15
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• 1982

There is the possibility that human error during testing and maintenance brings about the failure of the system, the reliability of which depends on mechanical failure and human error. This paper deals with the calculation of the reliability of the redundant system with the dependent hunman error through Karnaugh Map. Two cases are considered. One is the reli- ability of the system neglecting the test interval of each component and the other is that considering the test interval of each component.