• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.3
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• pp.365-372
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• 2013

In this study, a statistical method for evaluating the fatigue life of a vehicle muffler was used to obtain reliable fatigue data using a limited number of specimens. Cyclic bending tests were conducted using specimens manufactured to be exactly the same as the mufflers installed in cars that are currently in use. To estimate the fatigue life by comparing the data obtained during the fatigue tests, the most suitable probability density function for the normal, lognormal, and Weibull distributions was selected. A goodness-of-fit test was performed on the probability distributions, and then a Weibull distribution using the least square method was selected. By using the selected Weibull distribution, the probability-moment-life curves (P-M-N curve) reflecting the fatigue characteristics were suggested as the data for the reliable design of a muffler.

• The Korean Journal of Applied Statistics
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• v.30 no.5
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• pp.647-663
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• 2017

Weibull distribution is a popular distribution for modeling lifetimes because it reflects the characteristics of failure adequately and it models either increasing or decreasing failure rates simply. It is a standard method of the lifetimes test to wait until all samples failed; however, censoring can occur due to some realistic limitations. In this paper, we propose a generalized likelihood ratio (GLR) chart to monitor changes in the scale parameter for type I right-censored Weibull lifetime data. We also compare the performance of the proposed GLR chart with two CUSUM charts proposed earlier using average run length (ARL). Simulation results show that the Weibull GLR chart is effective to detect a wide range of shift sizes when the shape parameter and sample size are large and the censoring rate is not too high.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.4
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• pp.120-126
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• 1999

;The consicErations for reminder life of transmission line is gradually higher. It is requisite for investigation of ACSR's life to test tensile load of ACSR as a fundamental data. It is vary important to analysis correlations between results of tensile load testing and elasped years. Estimation of ACSR's life can be obtained by statistics processing using mechanical experirrental results. It is a general method to use regression analysis as a statistics processing technique. In this paper, we did experiment on tensile strength of ACSR by using a new and old ACSR as sample experirrental materials. The limit of life estimation is decided by basic line using twenty percentage reduction of rate tensile strength. This basic line is like to results of Canada Ontario Hydro-research. There are $95[\textrm{mm}^2]$, $97[\textrm{mm}^2]$, $120[\textrm{mm}^2]$, $240[\textrm{mm}^2]$ ACSRs which are experimented on this study. 1be life estimation of these ACSR is presented by table 1 to be obtained through the linear regression and nonlinear regression analysis. SPSS and statistics toolbox of matlab is used for analysis.lysis.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.283-288
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• 2005

Application of semiconductor sensors has widely spreaded into various industries because those have several merits like easy miniaturization and batch production comparison with previous mechanical sensors. But external conditions such as thermal and repetitive load have a bad effect on sensors's lifetime. Especially, this paper was focused on fatigue life of a interconnect made by various materials. Firstly we implemented the stress analysis for interconnect under thermal load and wording pressure. And the fatigue lifetime of each material was induced by Manson & Coffin Equation using the plastic stress-strain curve obtained by the plastic-elastic Finite Element Analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.5899-5905
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• 2014

Faults in electric power system can be a critical problem for vehicles. The system durability is determined mainly by the durability of their components and operating conditions. Monitoring the conditions of the electric power system may be necessary because it is very difficult to predict precisely when it will fail. Therefore, the aim of this study was to develop a diagnosis system for an electric power system of a vehicle. The alternator voltage, excitation voltage, lamp voltage, battery voltage, and engine rpm from a crank angle sensor are monitored continuously and the system fault can be then detected in real time. NI USB- 9201 DAQ and LabVIEW SW have been used to measure the voltages and analyze the data. Compared to conventional measurements for only each component, an integrated and portable measurement method was developed. In addition to the monitoring the electric power system in real time, the saved data from the measurement also provides valuable information to improve the durability of the components.

• Korea journal of population studies
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• v.19 no.1
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• pp.123-137
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• 1996

The goal of this study was to measure the level of health quantitatively by combining mortality and morbidity level of the Korean people. The 1989 Life Table was used for the mortality data. For the morbidity data, the 15-day morbidity survey (10, 940) the hospitalized patient survey (1, 770), chronic morbidity survey (7, 241) of the 1989 National Health Sunvey conducted by Korean Institute of Health and Social Affairs were utilized. The life table analysis technique of Sullivan was adopted. The morbidity period and disability period required for this method were estimated by measuring disability period rate and disability rate. The disability free life expectancy was estimated by excluding disability life expectancy from life expectancy. In case of males, the disability-free life expectancy at birth was 60.48 years. In case of females, the disability-free life expectancy at birth was 63.80 years. The percent of disability-free life expectancy to life expectancy was 90.63% at birth in case of males and 85.20% in case of females. The portion of females was lower than that of males in all age brackets. Therefore, the percent of time spent without disability condition to life expectancy was higher for females than males. Estimating disability-free life expectancy by region, it was 61.52 years at birth in urban area and 59.34 years in rural area in case of males. In case of females, it was estimated to be 64.60 years in urban area and 63.08 years in rural area. The life expectancy of Koreans was 66.73 years for males and 74.88 years for females, 8.15 years higher than males while disability-free life expectancy was 60.48 years for males, 63.80 years for females, only 3.32 years higher than males.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.10a
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• pp.384-390
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• 2003

현재 우리나라에서 공용중인 강철도교의 50% 이상이 공용기간 50년 이상 경과된 교량으로 구성되어 있지만 실교량에서 각 부재별 실측자료의 축적이 미흡한 실정이어서 유지관리시 구조물의 특성을 충분하게 반영하는 정량적인 평가가 체계적으로 이루어지고 있지 않은 실정이다.(중략)

• Journal of Korean Society for Quality Management
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• v.25 no.4
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• pp.206-212
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• 1997

This paper considers the problem of estimating parameters and reliability of shared parallel system with two identical components using type II censored system life data. Likelihood functions are derived and maximum likelihood estimates of parameters and reliability are discussed numerically.

• 전기의세계
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• v.42 no.7
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• pp.45-55
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• 1993

다른 차단기보다 성능이 우수하고 수명이 길며 보수점검이 용이하고 소형 경량화가 가능한 VCB의 이론을 차단원리, 구조와 기능, 소호원리, 개폐서지현상등으로 나누어 원리를 설명하였다. 또 VCB가 각 분야의 전력설비에의 차단기로서 적합함을 기술적으로 검토하였으며, 장래에 대한 전망과 우리나라의 기술수준을 밝히므로서, VCB 생산업체에서는 기술제고 노력을 촉구하였으며, 산업계에서 새로 건설하거나 기존 설비를 개조할때 VCB 채용을 위한 참고자료로 쓰이도록 노력하였다.

• KCID journal
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• v.13 no.1
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• pp.91-100
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• 2006