• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.287-292
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• 1998

As business looks towards the $21^{\st}$ century, a long-term strategy that focuses on global sourcing will be the vital factor in whether companies win or lose. At the same time, with electronic components, it is important to ensure stable quality and reliability, together with other important parameters. In order to achieve this, creating an effective mechanism of failure analysis and database management for electronic components is essential. The authors introduce the actual mechanism employed by NEC and explain the ideas and insight they have obtained from their experience.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1024-1029
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• 2010

The conventional factor of safety as used in geotechnical engineering does not reflect the degree of uncertainty of the relevant parameters. Then in the geotechnical engineering, there have been efforts to reflect the uncertainties of the geotechnical properties through probabilistic analysis. In this study, a practical method for calculation the second moment reliability index using the optimization tool of a spreadsheet software is introduced. And this methodology was proposed by Low, B. K.(1996). The method is based on the perspective of an ellipsoid that just touches the failure surface in the original space of the variables. The method is applied to vertical drains(PVD) and compared with th result of Monte Carlo Simulation method.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.6
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• pp.290-295
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• 2002

The present assignment in installing the number of switches for distribution line was made on the basis of a normal feeder capacity 7,000kVA in KEPCO(Korea Electric Power Corporation), Korea. But the normal capacity is revised to 10000kVA in 1998. Even increasing limit of the operating capacity of the distribution lines enables us to give some benefit for the operation flexibility and investment cost of the distribution system. It is disadvantageous in the viewpoint of supply reliability. In distribution systems, switches are equipped to improve the reliability of distribution systems by minimizing the outage section due to fault and maintenance. Utility generally improves the reliability by minimizing the length of outage section, which is caused by fault and maintenance, through switch equipment on distribution system. In order to cope with the changes such as operation capacity, it is necessary to study whether the present criteria is reasonable or not, also to confirm whether the present criteria of installing switches in line is improved or not. In this study, we proposes the number of switch per feeder on the basis of present operation capacity in distribution system.

• Journal of the Korean GEO-environmental Society
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• v.21 no.5
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• pp.13-21
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• 2020

In this study, the reliability of the lateral spring constant (k1) applied during design of pile foundation for bridge abutment was evaluated. To do this, the reliability of the factors related to the prediction of the lateral displacement of the abutment pile foundation, which was designed based on the displacement method proposed by Chang (1937), was analyzed. The data used for analysis were the design statements of ◯◯ bridge and ◯◯ IC2 bridge. Then, it was derived by comparing with the numerical analysis (p-y analysis) based on the basic data.

• Journal of Korean Society for Quality Management
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• v.48 no.4
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• pp.597-608
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• 2020

Purpose: The purpose of this paper is to present a probability distribution of the burst pressure of API 5L X65 pipes for the reliability assessment of corroded gas pipelines. Methods: Corrosion is a major cause of weakening the residual strength of the pipe. The mean residual strength on the corrosion defect can be obtained using the burst pressure code. However, in order to obtain the pipe reliability, a probability distribution of the burst pressure should be provided. This study is concerned with estimating the burst pressure distribution using Monte Carlo simulation. A response surface method is employed to represent the distribution parameter as a model of the corrosion defect size. Results: The experimental results suggest that the normal or Weibull distribution should be suitable as the probability distribution of the burst pressure. In particular, it was shown that the probability distribution parameters can be well predicted by using the depth and length of the corrosion defect. Conclusion: Given a corrosion defect on the pipe, its corresponding burst pressure distribution can be provided at instant. Subsequently, a reliability assessment of the pipe is conducted as well.

• 한국가스학회:학술대회논문집
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• 2005.05a
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• pp.197-197
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• 2005

• Proceedings of the Korea Water Resources Association Conference
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• 1991.07a
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• pp.49-60
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• 1991

• Culinary science and hospitality research
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• v.17 no.4
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• pp.104-120
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• 2011

This study is to make an empirical analysis of star marketing used as die means of sales promotion for Christmas cakes regardless of high advertising cos1s, by understanding the influence of attributes of celebrity advertising models for advertisements of bakery companies over die Christmas season on advertising attitude, corporation reputation and reliability which are recognized by consumers. The verification results were judged as important core elements for successful management in bakery industry. Since bakery brands are losing their differentiations in both functional and physical aspects, the study aimed to offer strategic suggestions to bakery industry. The result of study modelling were GFI=0.911, AGFI=0.887, NFI=0.935, CFI=0.979, RMR=.126 at the level of $x^2$=313.294(df-=218, p<0.001). First, model credibility and model attractiveness of advertising models bad a positive(+) influence on advertising attitude. Second, advertising attitude bad a positive(+) influence on corporation reputation and reliability. Third, corporate reputation also bad a positive(+) influence on corporate reliability.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.907-914
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• 2011

It has used for Rolling Stock Maintenance a number of maintenance system applied RCM in Railway(Korea Railroad Corporation, Seoul Metro, Korail Airport Railroad Corporation, etc) so far. Some institutions has been using develop Computational System including reliability process. A majority of the system has computerized maintenance work, but it is shown that developed focus on administrator and developer not user. SMRT(Seoul Metropolitan Rapid Transit Corporation) has developed computational system for maintenance in the '90s and saved many data about Maintenance Historical Data. However, this system reached the limits application of this data. Maintenance of computer systems is managed directly by the field staff and to introduce Reliability-centered maintenance SMRT was continually reviewed system development trends and supplement the existing system. To successfully operate RCM program should be gained full support in the whole company and field communicate, secure a reliable data from field and the most important take a patience. Our corporation will operate and develop successful RCM thorough review of these problems in the future.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.115-121
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• 2017

This paper is to introduce the main modeling assumptions and data structures associated with right-censored data to describe the successful methodological ideas for analyzing such a field-failure-data when components operating in different environments. The Kaplan - Meier method is the most popular method used for survival analysis. Together with the log-rank test, it may provide us with an opportunity to estimate survival probabilities and to compare survival between groups. An important advantage of the Kaplan - Meier curve is that the method can take into account some types of censored data, particularly right-censoring. The above non-parametric method was used to verify the equality of parts life used in different environments. After that, we performed the life distribution analysis using the parametric method. We simulated data from three distributions: exponential, normal, and Weibull. This allowed us to compare the results of the estimates to the known true values and to quantify the reliability indices. Here we used the Akaike information criterion to find a suitable life time distribution. If the Akaike information criterion is the smallest, the best model of failure data is presented. In this paper, no-nparametrics and parametrics methods are analyzed using R program which is a popular statistical program.