• Proceedings of the Safety Management and Science Conference
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• 2007.04a
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• pp.335-346
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• 2007

This paper introduces reliability stress screening(RSS) for electronic hardware and components. This study also shows reliability centered maintenance(RCM), and reliability growth models. Moreover, this paper presents goodness-of-fit tests and estimation methods of power law model.

• Journal of Korea Society of Industrial Information Systems
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• v.3 no.1
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• pp.67-77
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• 1998

Reliability growth testing used to evaluate reliability in the automobile industry have not always been able to correctly address reliability concerns with increased confidence. The demand to confirm to all product performance requirements under various operating environments has added to the complexity of accurately assessin theproduct's reliability in the required development time. In addition, it is often desired to determine the relationship of a product's reliability to cost, development time, design, manufacturability and assembly. This paper presents the methods for reliability growth modeling to evaluate and interpret reliability concerns to support the reliability analysis of automobile assemblies and systems. This reliability growth modeling process is a mechanism to help "build in" reliability during early phases in the vehicle devleopment stage.

• IE interfaces
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• v.19 no.1
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• pp.19-25
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• 2006

In the development process, the objective of a reliability growth program is to track the increase in system reliability, and determine as early as possible whether or not the system reliability is growing at a sufficient rate to meet the required goal and allocate available resources accordingly. Implementation of this kind of program will provide very useful information on concept selection, product/process reliability, and cost effectiveness without too much time, money and engineering effort being spent on the development of failure suspect parts. The purpose of this research is to present a practical method for efficiently monitoring a reliability growth test process using AMSAA(Army Materiel Systems Analysis Activity) reliability growth model. The presented growth management is a viable method for identifying failure modes, incorporating design changes and monitoring reliability progress on an on-going basis during the early stages of a product development program.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.305-312
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• 2016

Purpose: The purpose of this study is to provide a sensitivity analysis of system reliability for recognizing effectiveness of changing of BD mode failures using reliability growth projection model based on NHPP. Methods: Crow extended reliability projection model (CERPM) is used to analyze the changing of two factors 1) the number of BD mode failures, 2) fix effectiveness factor (FEF) values. Results: The system reliability has increased in accordance with the number of BD mode failures and FEF values have increased. Conclusion: It is necessary to design failure modes and FEF values to supervise the reliability.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.5
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• pp.637-644
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• 2010

This paper presents a reliability-based shape optimization (RBSO) using the growth-strain method. An actual design involves uncertain conditions such as material property, operational load, Poisson's ratio and dimensional variation. The purpose of the RBSO is to consider the variations of probabilistic constraint and performances caused by uncertainties. In this study, the growth-strain method was applied to shape optimization of reliability analysis. Even though many papers for reliability-based shape optimization in mathematical programming method and ESO (Evolutionary Structural Optimization) were published, the paper for the reliability-based shape optimization using the growth-strain method has not been applied yet. Growth-strain method is applied to performance measure approach (PMA), which has probabilistic constraints that are formulated in terms of the reliability index, is adopted to evaluate the probabilistic constraints in the change of average mises stress. Numerical examples are presented to compare the DO with the RBSO. The results of design example show that the RBSO model is more reliable than deterministic optimization. It was verified that the reliability-based shape optimization using growth-strain method are very effective for general structure. The purpose of this study is to improve structure's safety considering probabilistic variable.

• Journal of Applied Reliability
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• v.14 no.4
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• pp.225-229
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• 2014

A one-shot device is defined as a product, system, weapon, or equipment that can be used only once. After use, the device is destroyed or must undergo extensive rebuild. Determining the reliability of a one-shot device poses a unique challenge to the manufacturers and users due to the destructive nature and costs of the testing. This paper presents a reliability growth prediction for a one-shot system. It is assumed that 1) test duration is discrete(i.e. trials or rounds); 2) trials are statistically independent; 3) the number of failures for a given system configuration is distributed according to a binomial distribution; and 4) the cumulative expected number of failures through any sequence of configurations is given by AMSAA model. When the system development is represented by three configurations and the number of trials and failures during configurations are given, the AMSAA model parameters and reliability at configuration 3 are estimated by using a reliability growth analysis software. Further, if the reliability growth predictions do not meet the target reliability, the sample size of an additional test is determined for achieving the target reliability.

• Journal of the Korean Society for Railway
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• v.8 no.6 s.31
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• pp.597-601
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• 2005

Korea Railroad Research Institute(KRRI) developed the Driverless Rubber Tired Korea-AGT(Model: K-AGT) from 1999 to 2004. We have finished the safety and performance tests of K-AGT. Data obtained from this testing can be used to evaluate the growth of reliability. The most widely used traditional growth tracking model is included as IEC International standard. With the tracking model all corrective actions are incorporated during test, called test-fix-test. In the test-fix-test strategy problem modes are found during testing and corrective actions for these problems are incorporated during testing. In this paper, we demonstrated reliability analysis using growth model of driverless rubber tired K-AGT system to prove reliability of development system. Therefore, we introduce the well-known NHPP model and analyze a reliability growth using ReliaSoft's RGA software.

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.2
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• pp.157-173
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• 1993

Reliability growth modeling can be a requirement when bidding on large military hardware systems. Under current reliability warranty legislature, the reliability growth model can be later translated into necessary reliability performance which must be demonstrated over an extended period of usage. In this paper the modeling situation is concerned with determining the number of spares needed to support a projected reliability growth both at the fightine and in a depot inventory. The model differs from existing models for logistics planning in that we allow for the phenomena of reliability growth. The model can also be used to determine central depot staffing requirements based upon a specified system utilization.

• IE interfaces
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• v.12 no.1
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• pp.158-165
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• 1999

One solution to the estimation of product reliability during the development phase is to measure reliability improvement over time and compare this improvement to previous product development progress. This paper presents the reliability growth theory and applies it to some subsystems of vehicles during their design, development and prototype testing. The data presented illustrates explicitly the prediction of the reliability growth in the product development cycle. The application of these techniques is a part of the product assurance function that plays an important role in product reliability improvement.

• Journal of Applied Reliability
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• v.14 no.2
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• pp.129-136
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• 2014

Reliability test is focusing to detect the unexpected reliability failure and solve them for the high quality of products. The test data should be used to assess and project the current level of interesting product reliability and so it is very important to have the accurately assessing methodology with test data. There are two type of trend for test data as constant and changing one during testing and this paper shows the difference in the assessing results of these two cases. There is less information how to define the existence of reliability growth rate changing and calculate the parameters of the reliability growth models to make an accurate assessment with such condition, so i established the process and mathematical model to calculate the parameters at such condition to make reliability growth curve with high Goodness of Fit. I validated the new method with the data made from Monte Carlo Simulation and case from Demko (1993). Even the assessed result with the new methodology may be different with the case by case because of very diversity in test condition and testing product quality, but the process and method founded in this research can be applied to any case using Duane and AMSAA model for their test data assessment. I also present the evaluation method to see the effectiveness with new one which is a conventional knowledge and not popular to use, so it is possible to compare the results with the newly presented and conventional method for better business decision.