• International Journal of Reliability and Applications
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• v.15 no.1
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• pp.65-76
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• 2014

In this article, a new model based on Lomax distribution is introduced. This new model is both useful and practical in areas such as economic, reliability and life testing. Some statistical properties of this model are presented including moments, hazard rate, reversed hazard rate, mean residual life and mean inactivity time functions, among others. It is also shown that the distributions of the new model are ordered with respect to the strongest likelihood ratio ordering. The method of moment and maximum likelihood estimation are used to estimates the unknown parameters. Simulation is utilized to calculate the unknown shape parameter and to study its properties. Finally, to illustrate the concepts, the appropriateness of the new model for real data sets are included.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.50
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• pp.373-380
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• 1999

This paper summerizes the former 5 papers that studied computer programming for the estimation of the Weibull, Extreme value, Hazard, Normal and Log-normal parameters which have a close relation with the reliability of the various kinds of industrial products. Probability paper is very commonly used in estimating the parameters, however, it is very hard to neglect the errors in plotting the data, and especially in drawing the regression line. The main purpose of this paper is to reduce these errors and to help the engineers to use the parameters in improving the reliability of their prod- ucts. The following parts are included in the computer programming with the em- phases on significant digits and rounding of numerical values : $\bullet$ data input part for various cases $\bullet$ parameter estimation part $\bullet$ printing part for input data $\bullet$ printing part for the results $\bullet$ printing part for the graphic(probability paper). And the running results(monitor displays) of the program for a fictitious example of Weibull distribution is given for the interested ones.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.4
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• pp.368-378
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• 2002

As more companies are equipped with data aquisition systems for their products, huge amount of field warranty data has been accumulated. We focus on the case when the field data for a given product comprise with the number of sales and the number of the first failures for each period. The number of censored items and their ages are assumed to be given. This type of data are incomplete in the sense that the age of a failed item is unknown. We construct a model for this type of data and propose an algorithm for nonparametric maximum likelihood estimation of the product reliability. Unlike the nonhomogeneous Poisson process(NHPP) model, our method can handle the data with censored items as well as those with small population. A few examples are investigated to characterize our model, and a real field warranty data set is analyzed by the method.

• Journal of Integrative Natural Science
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• v.6 no.2
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• pp.111-117
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• 2013

We propose a mean value function for software failures in NHPP software reliability model. And we deal with the maximum likelihood estimation and the least squares estimation in the proposed mean value function. The explicit mean value function solution for the proposed model is presented by MLE and LSE in two data sets. The values of SSE and MSE is presented in two data sets by MLE and LSE. We compare the predicted number of faults with the actual two data sets using the proposed mean value function.

• Journal of Korea Society of Industrial Information Systems
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• v.8 no.4
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• pp.94-100
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• 2003

In this paper, we study the estimation of reliability function for a parallel system with k dependent exponential components. We assume that the failure of one of the k components changes the life distribution of the remaining components. Also, we compare with Cramer-Rna lower bound for variances of the minimum variance unbiased estimator, and the mean square errors of the maximum likelihood estimator of reliability system with the through the Monte Carlo simulation.

• Journal of Korean Society for Quality Management
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• v.22 no.3
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• pp.99-110
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• 1994

The strength-stress model has been widely used in a variety of areas including testing the reliability of the item or design procedures. This model was first introduced in 1950's and can be found on various applications in civil, aerospace engineering etc. This paper considers the strength-stress model in detail and proposes an estimator which deals with the reliability estimation problem based on censored observations in the strength variables.

• Journal of applied mathematics & informatics
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• v.41 no.6
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• pp.1275-1301
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• 2023

This paper introduced the Weibull Marshall-Olkin Power Lomax (WMOPL) distribution. The statistical aspects of the proposed model are presented, such as the quantiles function, moments, mean residual life and mean deviations, variance, skewness, kurtosis, and reliability measures like the residual life function, and stress-strength reliability. The parameters of the new model are estimated using six different methods, and simulation research is illustrated to compare the six estimation methods. In the end, two real data sets show that the Weibull Marshall-Olkin Power Lomax distribution is flexible and suitable for modeling data.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.1
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• pp.101-110
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• 2022

In this study, water content tests were performed on various fresh concretes subjected to different binder compostions to review the estimation errors and reliability of water content test methods. Micro-oven drying method, air-meter method, capacitance method and microwave penetration method were used to estimate water content of fresh concrete. Errors in water content estimation were analyzed by each test method. Regardless of the test method of water content, the estimation error was less than 5 %, and in the case of the test using mortar, the error in the estimation value was relatively large. In addition, based on the test results of water content of various concrete, the probability density function in which the estimation error for each test method becomes the population was analyzed. Water content test methods of fresh concrete which using concrete samples showed high estimate reliability of 97 % within the estimation error range of ± 10 kg/m³. On the other hand, the reliability of water content test method using mortar samples was lower.

• Journal of Korean Society for Quality Management
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• v.27 no.4
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• pp.241-255
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• 1999

This paper concerns Reliability Analysis System(RAS) developed by LG Electronics, Inc. for collecting, classifying, and analyzing field failure data. To develop this system, a database for the management of field failure data was built and several functions were included to analyze and assess the product reliability. Nonparametric estimation and cumulative hazard plotting techniques were applied to estimate the reliability for a specific period. This system serves not only engineers in charge of quality but also designers who wish to monitor the reliability of their own products.

• International Journal of Reliability and Applications
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• v.2 no.3
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• pp.189-197
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• 2001

The estimation of mean lifetimes in presence of interval censoring with mixed replacement procedure is examined when the distributions of lifetimes are exponential. It is assumed that, due to physical restrictions and/or economic constraints, the number of failures is investigated only at several inspection times during the lifetime test; thus there is interval censoring. The maximum likelihood estimator is found in an implicit form. The Cramor-Rao lower bound, which is the asymptotic variance of the estimator, is derived. The estimation of mean lifetimes for competing failures model has been expanded.