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

• Proceedings of the Korean Reliability Society Conference
• /
• 2005.06a
• /
• pp.147-155
• /
• 2005

When a failure or fault is detected, the product is adjusted or design change and is returned to its original condition before the failure or fault. Continuous improvement of the FMEA system is to determine an optimum product reliability that minimizes the total cost per unit time associated with inspection, repair, and the nondetection cost.

• International Journal of Reliability and Applications
• /
• v.2 no.2
• /
• pp.117-130
• /
• 2001

Consider the problem of estimating the system reliability using noninformative priors when both stress and strength follow generalized gamma distributions. We first treat the orthogonal reparametrization and then, using this reparametrization, derive Jeffreys'prior, reference prior, and matching priors. We next provide the suffcient condition for propriety of posterior distributions under those noninformative priors. Finally, we provide and compare estimated values of the system reliability based on the simulated values of the parameter of interest in some special cases.

• Journal of the Korea Safety Management & Science
• /
• v.8 no.5
• /
• pp.253-264
• /
• 2006

This paper is to derive three reliability and eight maintainability measures after organizing total time. I propose inherent availability,.achieved availability and operational availability with the new and useful reliability and maintainability measures above. Especially, inherent availability measure extends the repairable system reliability models.

• Structural Engineering and Mechanics
• /
• v.63 no.6
• /
• pp.789-797
• /
• 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.

• International Journal of Reliability and Applications
• /
• v.11 no.1
• /
• pp.55-67
• /
• 2010

There has been a recent upsurge in demand for the improvement of car reliability in the Northern American which is the primary market of South Korea automobile industry. It has been required that the warranty for transmission control unit for passenger cars directly related to passenger safety or security should be extended for 10 years and 160,000 km. In this paper, the test method for reliability and evaluation criteria is presented to evaluate the reliability on the automatic transmission controller. Reliability certification test can be roughly divided into two types: a quality test and life assessment test and a quality test can be subdivided into a basic performance test and environmental resistance test. There are 3 types of tests on the performance test for automatic transmission controller and environmental resistance test is composed of 14 items. Life test is performed with only the product passed this quality test. In this study, operation limit test at the high-temperatures, accelerated life test under specific temperature and accelerated life test for 2 or 3 stress levels are shown as a way for life test.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.206-210
• /
• 2007

IEC 62278 presents a process to implement a consistent approach to the management of reliability for railway applications. A reliability program has to be established at the outset of a project in order to manage reliability activities effectively through the life cycle. The first step of the reliability program is to evaluate reliability requirements and targets based on the system specifications. The system specifications are derived from the customer's needs. The way in which the system requirements reflect the customer's needs is strongly dependent on the characteristics of the product. In general the customer of commercial trains presents the system requirements from their needs. However, the relation between the customer and supplier is equivocal for a project to development a prototype train, and the reliability program should be different from that of an usual commercial project. This paper deals with a process to manage reliability activities for the development of a protype train based on the experiences obtained from the development of the Korea High-Speed Train: Hanvit-350.

• Journal of Information Technology Applications and Management
• /
• v.10 no.4
• /
• pp.185-194
• /
• 2003

One method to improve S/W quality before releasing after development is to enhance the its reliability, whose direct methodology is to detect and revise the fault through testing. Once the S/W is released because it meets the target reliability, We operational reliability arises. it is obvious the operational reliability different depending on the condition whether it is universal(package) S/W or dedicated S/W. We propose the methodology to calculate operational software reliability of universal and dedicated S/Ws in this paper.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.24 no.1
• /
• pp.110-114
• /
• 1987

It is known that digital circuits may produce correct output signals even when some faults are present in them. A reliability measure, known as signal reliability, is the probability that the circuit output is correct. In this paper, the reliability measure is analyzed first and a new procedure for evaluation of the signal reliability is presented. This procedure simplifies signal reliability calculations and can easily be mechanized.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.37 no.9
• /
• pp.1169-1174
• /
• 2013

Most products are indeed governed by multiple failure modes. However, there are few cases in which reliability analysis applies to only one failure mode at a time. Furthermore, reliability data do not include information about failure modes, or the reliability analysis is performed using a representative failure mode. The Weibull shape parameter for failure modes is more important than one for products in the reliability qualification test. This paper presents reliability analysis methods for a mechanical component with multiple failure modes. These methods include the competing failure modes (CFM) method and the mixed Weibull method. Pneumatic cylinder test data with three failure modes are presented to estimate the shape parameter for each separate failure mode. In addition, reliability measures (B10 life, characteristic life) of the pneumatic cylinder considering three failure modes were compared with those assuming a single failure mode.