• Journal of Korean Society for Quality Management
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• v.24 no.3
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• pp.19-30
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• 1996

We treat problems of estimating reliability R(t) = P[Y(t) ＞ X(t)] in the time dependent strength-stress model in which a unit of stress X(t) is subjected to environmental strength Y(t) at time t. In this paper we introduce a special model of R(t) with fixed strength and unaccumulated stress case, and propose a Mann-Whitney-Wilcoxon type estimator of R(t).

• Journal of Korean Society for Quality Management
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• v.9 no.1
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• pp.3-11
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• 1981

A stress-strength model is formulated for s of k systems consisting of identical components. We consider minimum variance unbiased (MVU) estimation of system reliability for data consisting of a random sample from the stress distribution and one from the strength distribution when the two distirubtions are Weibull with unknown scale parameters and same known shape parameter. The asymptotic distribution of MVU estimate of system reliability in the model is obtained by using the standard asymptotic properties of the maximum likelihood estimate of system reliability and establishing their equivalence. Uniformly most accurate unbiased confidence intervals are also obtained for system reliability. Empirical comparison of the two estimates for small samples is studies by Monte Carlo simulation.

• Journal of Korean Society for Quality Management
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• v.10 no.1
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• pp.2-6
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• 1982

Suppose a system with m components is subjected to a random stress. We consider the estimation of reliability when data consist of random samples from the stress distribution and the strength distributions. All the distributions are assumed to be independent exponential with unknown scale parameters. An explicit form of system reliability and the minimun variance unbiased estimator are obtained. The asymptotic distribution is also obtained by expanding the minimum variance unbiased estimator about the maximum likelihood estimator and establishing their equivalance. The performance of the two estimators is compared by Monte Carlo Simulation.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2007.03a
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• pp.351-357
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• 2007

We have compared a special character(pressure of explosion, gas volume, energy of explosion, temperature of explosion, strength) of different three emulsion explosives which is different velocity by Nitrodyn program that is calculated explosion reaction. We have analyzed the character of the vibration from a vibration data which is a result from test blasting in different velocity of detonation for three emulsion explosives of the same size(17mm) in the same rock. As a result, the vibration is decreased when the velocity of detonation is decreased within 40m from origin of explosion but it is familiar character over 40m, so there isn't much affect the velocity of detonation in decreased vibration over 40m.

• Journal of architectural history
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• v.31 no.5
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• pp.57-64
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• 2022

Architectural Monuments have to overcome the challenge of time due to physical properties. The fundamental issue must be grounded in an understanding of history and art to overcome this challenge and make themsustainable. Many efforts to preserve the monuments through the 19^th century and at the beginning of the 20^th century to record them in scientific form were successful. To be aware of the meaning of the art and not to be 'barbare' anymore was behind the promotion of these activities. Above all, the 19th-century French architect Viollet-le-Duc contrasted the concept of barbarism with the concept of art and tried to redefine architecture as art. The ritual to escape 'barbare' played an important role in the end. This consciousness was also at work in the propaganda for the preservation of medieval architectural monuments in France, led by intellectuals such as Rodin. Also, the concept of 'barbare' served as an important yardstick whenever the cause of their loss was questioned while important monuments were destroyed in the First World War. From the viewpoint of Germany, Dehio was the pioneer of the preservation movement and documentation of monuments. The principle he advocated was preservation, not restoration. The historian Pevsner, who moved to England, also surveyed monuments in various parts of England and left them in the same format as Dehio. These facts show that architecture as art plays a fundamental role in the history of human life.