• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.111-118
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• 2006

Recently, the reliability evaluation and analysis are applied far many industrial products which are required to guarantee in quality and efficiency. The purpose of this paper is to present some of reliability evaluation methodologies that are applicable to machine tools. Especially ATC (Automatic Tool Changer), which is a core component of line center, was chosen as the target of the reliability evaluation and analysis. The scope of research is reliability prediction, reliability test and evaluates their results. The results of reliability evaluation have shown the failure rates, MTBF (Mean Time Between Failure), reliability for those components of ATC and real tests reliability through the constructed reliability test-bed. It is expected that proposed methodologies would increase reliability for a high-speed line center.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.1
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• pp.9-16
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• 2003

In this paper, we propose a reliability evaluation method considering the momentary interruptions of power distribution systems. The results of research are concentrated on two parts. One is the analytic and probabilistic reliability evaluation of power distribution system considering the momentary interruptions and the other is the reliability cost evaluation that unifies the cost of sustained and momentary interruptions. This proposed reliability cost evaluation methodology is also divided into the analytic and probabilistic approach and the time sequential Monte Carlo method is used for the probabilistic method. The proposed methods are tested using the modified RBTS (Roy Billinton Test System) form and historical reliability data of KEPCO (Korea Electric Power Corporation) system. Through the case studies, it is verified that the proposed reliability evaluation and its cost/worth assessment methodologies can be applied to the actual reliability studies.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.12
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• pp.705-712
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• 2003

In this paper, we propose new unified methodologies of reliability and its cost evaluation in power distribution systems. The unified method means that the proposed reliability approaches consider both conventional evaluation factor, i.e. sustained interruptions and additional ones, i.e. momentary interruptions and voltage sags. Because the three voltage quality phenomena generally originate from the outages on distribution systems, the basic and additional reliability indices are summarized considering the fault clearing mechanism. The proposed unified method is divided into the reliability evaluation for calculating the reliability indices and reliability cost evaluation for assessing the damage of customer. The analytic and probabilistic methodologies are presented for each unified reliability and its cost evaluation. The time sequential Monte Carlo technique is used for the probabilistic method. The proposed DVL(Demand Varying Load) model is added to the reliability cost evaluation substituting the average load model. The proposed methods are tested using the modified RBTS(Roy Billinton Test System) form and historical reliability data of KEPCO(Korea Electric Power Corporation) system. The daily load profile of the each customer type in domestic are gathered for the DVL model. Through the case studies, it is verified that the proposed methods can be effectively applied to the distribution systems for more detail reliability assessment than conventional approaches.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1914-1917
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• 2005

Recently, the reliability evaluation and analysis are applied for many industrial products, and many products are required to guarantee in quality and in efficiency. The purpose of this paper is to present some of reliability evaluation methodologies that are applicable to machine tools. Especially ATC(Automatic Too Changer), which is core component of line center, was chosen as the target of the reliability evaluation and analysis. The scope of research is reliability prediction, reliability test and evaluates their results. The results of this research has shown the failure rate, MTBF(Mean Time Between Failure), reliability for those components and real tests reliability through constructed reliability test-bed. It is expected that proposed methodologies will increase reliability for high speed line center.

• Journal of Applied Reliability
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• v.5 no.3
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• pp.315-319
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• 2005

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.147-148
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• 2001

The construction of reliability evaluation according to their fields was promoted under the supervision of Agency for Technology and Standards for establishing the relevant institution & infrastructure that can fundamentally solve the reliability problems, the biggest obstruction when the developed electric components & materials come into the market. This paper describes the criterion of reliability evaluation and the evaluation facilities for the purpose of heightening the reliability of composite insulator estimated as the new material among the electric components & materials. We will understand the criterion of reliability evaluation with two parts as the performance evaluation based on various kinds of standards (especially IEC) and as the long-term reliability evaluation utilizing the accelerated aging & flashover test methods. Therefore we aim for constructing the criterion of reliability evaluation as the foundation for evaluation so as to support the industrial group based on KERI facilities.

• International Journal of Knowledge Content Development & Technology
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• v.9 no.2
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• pp.65-89
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• 2019

This study has the aim of developing an evaluation index that can help evaluate the reliability of the information resources of institutions retaining humanities assets for the purposes of laying out the foundation for providing one-stop portal service for humanities assets. To this end, the evaluation index was derived through the analysis of previous research, case studies, and interviews with experts, the derived evaluation index was then applied to the humanities assets retaining institutions to verify the utility. The institutional information resources' reliability evaluation index consisted of the two dimensions of the institutions' own reliability evaluation index. The institution provided a service and system evaluation index. The institutions' own reliability evaluation index consisted of 25 points for institutional authority, 25 points for data collection and construction, 30 points for data provision, and 20 points for appropriateness of data, for a total of 100 points, respectively. The institution provided service and system evaluation indexes consisting of 25 points for information quality, 15 points for appropriateness (decency), 15 points for accessibility, 20 points for tangibility, 15 points for form, and 10 points for cooperation, for the total of 100 points, respectively. The derived evaluation index was used to evaluate the utility of 6 institutions representing humanities assets through application. Consequently, the reliability of the information resources retained by the Research Information Service System (RISS) of the Korea Education & Research Information Service (KERIS) turned out to be the highest.

• Proceedings of the Korean Reliability Society Conference
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• 2001.06a
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• pp.105-111
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• 2001

In this study, for improvement of pneumatic valve reliability, we grasped the falling-off problem in efficiency of domestic valve and performed detailed analysis the relating International standards, and we also decided sampling method and reliability evaluation items to be evaluated valves. And, in addition, we describe the developed evaluation standard to increase the competition power and to improve the reliability of domestic pneumatic valve manufacturers through deciding of test conditions and thesis of evaluation procedures to each evaluation items.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.3
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• pp.50-53
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• 2007

Improving the reliability or long-term dependability of a system requires a different approach from the previous emphasis on short-term concerns. The purpose of this paper is to present a reliability evaluation method for an oil cooler intended for high-precision machining centers. The oil cooler system in question is a cooling device that minimizes the deformation caused from the heat generated by driving devices. This system is used for machine tools and semiconductor equipment. We predicted the reliability of the system based on the failure rate database and conducted the reliability test using a test-bed to evaluate the life of the oil cooler. The results provided an indication of the reliability of the system in terms of the failure rate and the MTBF of the oil cooler system and its components, as well as a distribution of the failure mode. These results will help increase the reliability of oil cooler systems. The evaluation method can also be used to determine the reliability of other machinery products.

• Structural Engineering and Mechanics
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• v.63 no.6
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• pp.789-797
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• 2017

Recently, some integrated structural identification/damage detection and reliability evaluation of structures with uncertainties have been proposed. However, these techniques are applicable for off-line synthesis of structural identification and reliability evaluation. In this paper, based on the recursive formulation of the extended Kalman filter, an on-line integration of structural identification/damage detection and reliability evaluation of stochastic building structures is investigated. Structural limit state is expanded by the Taylor series in terms of uncertain variables to obtain the probability density function (PDF). Both structural component reliability with only one limit state function and system reliability with multi-limit state functions are studied. Then, it is extended to adopt the recent extended Kalman filter with unknown input (EKF-UI) proposed by the authors for on-line integration of structural identification/damage detection and structural reliability evaluation of stochastic building structures subject to unknown excitations. Numerical examples are used to demonstrate the proposed method. The evaluated results of structural component reliability and structural system reliability are compared with those by the Monte Carlo simulation to validate the performances of the proposed method.