• 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.

• 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.

• 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.

• 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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.576-581
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• 2008

Electricity Market in Korea can't provide locational price signal through energy price because energy market is CBP(Cost Based Pool) using uniform price. Generators don't want to locate in a densely populated load area(like the metropolitan area). Because they are paid more fixed cost in metropolitan area. This situation has loss and congestion occurred in power system. However energy market without price signal can't lead generator to the metropolitan. So, market participants should be provided price signal through the transmission price instead of energy price. This paper proposes transmission pricing method considering reliability cost in order to offer price signal. Also, it proposes the method to allocate the transmission cost to each transmission line user through a fair and a reasonable manner. The transmission price is decided by the reliability value of each line. If a transmission line of high reliability value is broke, users using that line will get a loss and a discomfort. So, it is fair that users using a transmission line of high reliability value pay more than the other users. Also, it is reasonable that a transmission line owner get paid more form users using that line.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.4
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• pp.183-187
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• 2002

The efficient and rational transmission tariff structure is one of the crucial factors in creation of fair and competitive electricity markets. Transmission charge can be largely categorized into the line usage charge, system reliability charge, access charge and others. Any transmission tariff should be able to reflect these cost components reasonably. This paper suggests an approach amenable to allocating the transmission reliability costs reasonably with reflection of line sensitivity and line outage rate.

• Journal of the Korea Safety Management & Science
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• v.7 no.4
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• pp.207-217
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• 2005

Line capacity calculation has been used to determine optimum efficiency and safe train service for train scheduling plan and investment priority order throughout detecting bottleneck section. Because of some problems of Yamagisi and UIC methods for line capacity calculation, developing of the method of line capacity caculation and evaluation for the Korea circumstance is important. This paper deals with the reliability improvement on the integrated system of TPS(Train Performance Simulator), PES(Parameter Evaluation Simulator), LCS(Line Capacity Simulator) and simulation and sensitivity analysis for line capacity.

• KIEE International Transactions on Power Engineering
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• v.5A no.1
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• pp.31-39
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• 2005

This paper illustrates a tie line constrained equivalent assisting generator (TEAG) model considering forced outage rates of transmission systems for reliability evaluation of interconnected power systems. Interconnections between power systems can provide improved levels of reliability. It is expected that the TEAG model developed in this paper will prove useful in the solution to problems related to the effect of transmission system uncertainties in the reliability evaluation of interconnected power systems. It is important that interconnection between power systems can provide the improved levels of reliability. Therefore, It is expected that the TEAG model developed in this study will provide some solution among many problems for interconnected power systems as an optimal tie line capacity and a connected point between assisting systems and assisted system. The characteristics and validity of this developed TEAG considering transmission systems are introduced by case study of three IEEE MRTS interconnected.

• International Journal of Reliability and Applications
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• v.2 no.3
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• pp.161-187
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• 2001

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 reliability, failure rate, product life, and durability are explained. From the customer's standpoint, the concept of product quality is classified in five factors, according to related technology: performance, reliability, conformance to specifications, customer perception, and fundamentals advantage. The correlation of the five factors for a first-class product is discussed, Since the market share of a company is determined as the competition result of its product value, defined as product quality and price, the market share increase is derived mathematically from the increment of product value. The market share increase, $\Delta$S, can be calculated from the present market share, S, and the oriented relative value increment of new product, R, to the current product in the same company for the same market target: $\Delta$S : $\Delta$(1-S). R/(1+S.R). Finally, the importance of separating warranty cost from the profit equation for the durables is explained.

• Journal of the Korean Society of Safety
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• v.30 no.4
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• pp.26-31
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• 2015

The purpose of this paper is to measure the induced voltage of the downscaled and simulated overhead ground wire of a 22.9kV-Y distribution line. This study performed a test of the downscaled and simulated distribution line according to whether it is grounded or not and the value of the ground resistance. In order to verify the reliability of the data measured by the test, the data was analyzed using the Minitab 17 program. It was found that the induced voltage of the downscaled and simulated distribution line is influenced by the value of the ground resistance. It was also found that the ground resistance obtained at a certain point is closely related to whether electric poles are grounded or not. The analysis results of the measured test data with a statistical method showed that the Anderson Darling (AD) was analyzed to be the smallest as 0.188 when the ground resistance of the electric poles had been maintained at $10{\Omega}$. In addition, the P value analyzed to be 0.894 which is in the proximity of the theoretical value of 1 and verified the reliability of the test data. It could be seen that the data measured by the downscaled simulation test forms a linear graph. It is thought that if a distribution line is installed in the same manner as the downscaled, simulated distribution line, the mean induced voltage will be reduced and reliability will be increased.