• Journal of the Korean Society of Physical Medicine
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• v.18 no.2
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• pp.93-101
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• 2023

PURPOSE: The Western Ontario and McMaster Universities Arthritis (WOMAC) index has been used to measure the outcome of total knee replacement (TKR), but studies on its reliability and validity are limited. The present study examined the reliability and validity of this index for patients with knee osteoarthritis who underwent TKR. METHODS: Seventy-one inpatients and outpatients who underwent bilateral TKR for knee osteoarthritis were included in this study. The pain assessment scale and WOMAC index were used to evaluate the participants every two weeks to examine the test-retest reliability, internal consistency, and construct validity. RESULTS: The test-retest reliability scores for pain, stiffness, and physical function were .75-.92, .85-.90, and .75-.95, respectively. The corresponding intraclass correlation coefficients were .75-.88, .76-.88, and .71-.95, respectively. The internal consistency score in the first and second examinations was .92. Furthermore, the construct validity scores for pain, stiffness, and physical function were .83, .41, and .58, respectively. CONCLUSION: The application of the WOMAC index in patients who underwent TKR showed high test-retest reliability and internal consistency with the use of the WOMAC index and good validity with the use of the pain assessment scale.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.6
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• pp.445-452
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• 2015

Software reliability in the software development process is an important issue. Software process improvement helps in finishing with reliable software product. Infinite failure NHPP software reliability models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, proposes the reliability model with log and power intensity function (log linear, log power and exponential power), which made out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on mean square error (MSE) and coefficient of determination($R^2$), for the sake of efficient model, was employed. Analysis of failure, using real data set for the sake of proposing log and power intensity function, was employed. This analysis of failure data compared with log and power intensity function. In order to insurance for the reliability of data, Laplace trend test was employed. In this study, the log type model is also efficient in terms of reliability because it (the coefficient of determination is 70% or more) in the field of the conventional model can be used as an alternative could be confirmed. From this paper, software developers have to consider the growth model by prior knowledge of the software to identify failure modes which can be able to help.

• Korean Journal of Child Studies
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• v.31 no.3
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• pp.235-254
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• 2010

The purpose of this study was to examine the feasibility and validity of the Application of Cognitive Function Scale as developed by Lidz and Jepsen (1997). Data were collected from 4 to 5-years-old children. The analysis for item adequacy indicated that the passing rate increases according to age. Futhermore the analysis for test adequacy indicated that internal consistency reliability was .85 in the pre-test and .80 of post-test in terms of the cognitive function scale, and .90 of pre-test and .93 in the post-test in relation to the behavior observation scale. In conclusion, our analysis of the ACFS shows sufficiently high scores in terms of both validity and reliability, so as to indicate that this test is an appropriate way to measure the cognitive function and non-intellective function of young Korean children.

• Structural Engineering and Mechanics
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• v.38 no.5
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• pp.651-674
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• 2011

This paper presents a novel method for predicting the failure probability of structural or mechanical systems subjected to random loads and material properties involving multiple design points. The method involves Multicut High Dimensional Model Representation (Multicut-HDMR) technique in conjunction with moving least squares to approximate the original implicit limit state/performance function with an explicit function. Depending on the order chosen sometimes truncated Cut-HDMR expansion is unable to approximate the original implicit limit state/performance function when multiple design points exist on the limit state/performance function or when the problem domain is large. Multicut-HDMR addresses this problem by using multiple reference points to improve accuracy of the approximate limit state/performance function. Numerical examples show the accuracy and efficiency of the proposed approach in estimating the failure probability.

• Journal of Applied Reliability
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• v.1 no.1
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• pp.35-46
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• 2001

Replacement policy of a degradation system is investigated by incorporating the loss function. Loss function is defined by the deviation of the value of quality characteristic from its target value, which determines the loss cost. Cost function is comprised of the inspection cost, replacement cost and loss cost. Two cost minimization problems are formulated : 1)determination of an optimal inspection period given the state for the replacement and 2)determination of an optimal state for replacement under fixed inspection period. Simulation analysis is performed to observe the variation of total cost with respect to the variation of the parameters of loss function and inspection cost, respectively As a result, parameters of loss function are seen to be the most sensitive to the total cost. On the contrary, inspection cost is observed to be insensitive. This study can be applied to the replacement policy of a degradation system which has to produce the quality critical product.

• Journal of the Korean Data and Information Science Society
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• v.25 no.3
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• pp.623-632
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• 2014

We shall consider the estimation for the parameter and the right tail probability in a general exponential distribution. We also shall consider the estimation of the reliability P(X < Y ) and the skewness trends of the density function of the ratio X=(X+Y) for two independent general exponential variables each having different shape parameters and known scale parameter. We then shall consider the estimation of the failure rate average and the hazard function for a general exponential variable having the density function with the unknown shape and known scale parameters, and for a bivariate density induced by the general exponential density.

• Korean Journal of Mathematics
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• v.5 no.1
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• pp.55-60
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• 1997

A continuum structure function(CSF) is a non-decreasing mapping from the unit hypercube to the unit interval. The reliability importance of component $i$ in a CSF at system level ${\alpha}$, $R_i({\alpha})$) say, is zero if and only if component $i$ is almost irrelevant to the system at level ${\alpha}$. A condition to check whether a component is almost irrelevant to the system is presented. It is shown that $R^{(m)}_i({\alpha}){\rightarrow}R_i({\alpha})$ uniformly as $m{\rightarrow}{\infty}$ where each $R^{(m)}_i({\alpha})$ is readily calculated.

• Journal of Industrial Technology
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• v.29 no.A
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• pp.101-110
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• 2009

Due to frequent occurrence of a localized torrential downpour caused by global warming and change of outflow tendency caused by rapid urbanization and industrialization, risk analysis must be carried out in levee design with uncertainty. In this study, reliability analysis was introduced to quantitatively evaluate the overtopping risk of levee by the uncertainty. First of all, breaking function was established as a function of flood stage and height of levee. All variables of breaking function were considered as random variables following any distribution functions, and the risk was defined as the possibility that the flood stage is formed higher than height of levee. The risk evaluation model was developed with AFDA (Approximate Full Distribution Approach). The flood stage computed by 2-D numerical model FESWMS-2DH was used as input data for the model of levee risk evaluation. Risk for levee submergence were quantitatively presented for levee of Wol-Song-Cheon.

• Journal of the Korean Data and Information Science Society
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• v.18 no.3
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• pp.783-792
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• 2007

We consider estimation of reliability P(Y

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.70-72
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• 2000

The basic function of a modern electric power system is to provide electric power to its customers at the lowest possible cost with acceptable reliability levels. The two aspects of economics and reliability often conflict and present power system managers, planners and operators with a wide range of challenging problems. Utilities may also be willing to provide higher reliability of power supply at no increased customer cost. Decision-making is a difficult task. In this paper, we present a method to calculate the optimal values of reliability indices for sectionalizing distribution line.